U.S. patent application number 15/259434 was filed with the patent office on 2017-01-05 for sportsboard structures.
This patent application is currently assigned to NOVA Chemicals Inc.. The applicant listed for this patent is INT Softboards Technology, LLC, NOVA Chemicals Inc.. Invention is credited to Paul E. Arch, Christopher Griffin, Louis G. Hayward.
Application Number | 20170001694 15/259434 |
Document ID | / |
Family ID | 39788987 |
Filed Date | 2017-01-05 |
United States Patent
Application |
20170001694 |
Kind Code |
A1 |
Hayward; Louis G. ; et
al. |
January 5, 2017 |
SPORTSBOARD STRUCTURES
Abstract
A sports board that includes an elongate, water impervious,
thermoplastic foam core having an upper surface and an under
surface; an upper layer covering at least a portion of the upper
surface; and an under layer covering at least a portion of the
under surface. The foam core is made of a foamed material having a
water absorption (measured according to ASTM C-272) of less than 2
volume percent.
Inventors: |
Hayward; Louis G.;
(Carlsbad, CA) ; Griffin; Christopher;
(Pittsburgh, PA) ; Arch; Paul E.; (Coraopolis,
PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NOVA Chemicals Inc.
INT Softboards Technology, LLC |
Moon Township
Carlsbad |
PA
CA |
US
US |
|
|
Assignee: |
NOVA Chemicals Inc.
Moon Township
PA
INT Softboards Technology, LLC
Carlsbad
CA
|
Family ID: |
39788987 |
Appl. No.: |
15/259434 |
Filed: |
September 8, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13761488 |
Feb 7, 2013 |
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15259434 |
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12053849 |
Mar 24, 2008 |
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13761488 |
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60920073 |
Mar 26, 2007 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A63C 5/122 20130101;
B63B 34/54 20200201; B63B 32/00 20200201; B63B 32/20 20200201; A63C
5/003 20130101; A63C 5/031 20130101; A63C 5/03 20130101; B63B 32/57
20200201; A63C 5/126 20130101 |
International
Class: |
B63B 35/79 20060101
B63B035/79 |
Claims
1. A surfboard comprising: (a) an elongate, water resistant,
thermoplastic foam core having an upper surface and an under
surface, a nose end, a tail end, and a stringer encased in the foam
core extending from the nose end to the tail end; (b) an upper
layer covering at least a portion of the upper surface; and (c) an
under layer covering at least a portion of the under surface;
wherein the foam core is made of a foam material 50 to 100 percent
based on the weight of the foam material of expanded and fused
interpolymer resin particles containing from about 20% to about 80%
by weight of a polyolefin and from about 80% to about 20% by
weight; wherein the density of the foam core is from about 0.02
g/cc to about 0.64 g/cc and the density of the foam core is higher
at the nose end and tail end as compared with the rest of the foam
core; wherein the foam core comprises a skin, consisting of the
foam material, formed on the upper surface and under surface;
wherein the foam core has a water absorption (measured according to
ASTM C-272) of less than 2 volume percent wherein the upper layer
and under layer comprise a cloth comprising a fiber selected from
the group consisting of carbon fibers, graphite fibers, aramid
fibers, metal fibers, glass fibers, silicon carbide fibers,
polyester fibers, composite fibers, and fiberglass; and wherein the
cloth is encased in a laminating resin, which forms a bond to the
thermoplastic foam core.
2-4. (canceled)
5. The surfboard according to claim 1, wherein a sealant is applied
to at least a portion of the outer surface or under surface of the
foam core.
6. The surfboard according to claim 5, wherein the sealant
comprises a material selected from the group consisting of
ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol
copolymers, ethylene-acrylic acid copolymers, styrene-butadiene
polymers, styrene-isoprene polymers; styrene-butadiene-styrene
block polymers; styrene-isoprene-styrene block polymers; and
hydrogenated resins thereof.
7. The surfboard according to claim 1, wherein the foam core has a
flexural strength at 5% strain, measured according to ASTM C-203,
of at least 60 psi at a molded density of about 2.25
lb/ft.sup.3.
8. The surfboard according to claim 1, wherein the foam core has a
tensile strength (measured according to ASTM D-3575-T) of at least
75 psi at a molded density of about 2.25 lb/ft.sup.3.
9-10. (canceled)
11. The surfboard according to claim 1, wherein the laminating
resin comprises a resin selected from the group consisting of
unsaturated polyester resins, saturated polyester resins, epoxy
resins, phenol-formaldehyde resins, melamine-formaldehyde resins,
urea-formaldehyde resins, unsaturated polyesteramide resins, vinyl
ester resins, polyimide resins, poly amide-imide resins,
unsaturated (meth)acrylic resins, acrylic-urethane resins, and
combinations thereof.
12. The surfboard according to claim 1, wherein the upper layer
covering and/or under layer covering comprise one or more
polyolefins.
13-25. (canceled)
26. The surfboard according to claim 1, wherein the stringer is an
axial or a parabolic stringer.
27. The surfboard according to claim 1, comprising one or more fins
secured to and extending from the under surface of the
surfboard.
28. The surfboard according to claim 1, wherein the surfboard can
be deflected 0.75 inches (1.9 cm) without demonstrating a
deflection in the stress-strain curve.
29. The surfboard according to claim 1, wherein the surfboard does
not fail when deflected 0.87 inches (2.2 cm).
30. A sports board comprising (a) an elongate, water resistant,
thermoplastic foam core having an upper surface, an under surface,
a nose end and a tail end; (b) an upper layer covering at least a
portion of the upper surface; and (c) an under layer covering at
least a portion of the under surface; wherein the foam core is made
of a foam material comprising 50 to 100 percent based on the weight
of the foam material of expanded and fused interpolymer resin
particles containing from about 20% to about 80% by weight of a
polyolefin and from about 80% to about 20% by weight; wherein the
density of the foam core is from about 0.02 g/cc to about 0.64 g/cc
and the density of the foam core is higher at the nose end and tail
end as compared with the rest of the foam core; wherein the foam
core comprises a skin, consisting of the foam material, formed on
the upper surface and under surface; wherein the foam core has a
water absorption of less than 2 volume percent measured according
to ASTM C-272; wherein the upper layer and under layer comprise a
cloth comprising a fiber selected from the group consisting of
carbon fibers, graphite fibers, aramid fibers, metal fibers, glass
fibers, silicon carbide fibers, polyester fibers, composite fibers,
and fiberglass; and wherein the cloth is encased in a laminating
resin, which forms a bond to the thermoplastic foam core.
31. The sports board according to claim 30, wherein the sports
board is selected from the group consisting of a surfboard, a body
board, a sailboard, a wave board, a tow board, a water ski, a snow
board, a sled, a toboggan, and a snow ski.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of priority of U.S.
Provisional Application Ser. No. 60/920,073 filed Mar. 26, 2007
entitled "Sportsboard Structures," which is herein incorporated by
reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention is directed to novel sports boards
that can be used for various sporting activities.
[0004] 2. Description of the Prior Art
[0005] Boards and modified boards have been used for various sports
and/or athletic activities such as for example surfing, riding
waves, sail boarding, being towed by a boat, water skiing, snow
boarding, sledding, snow skiing, and skate boarding.
[0006] Surfboards are flat or slightly curved narrow floating
bodies which are suitable for use for one or more individuals to
move along with or ride a swell or wave of water as it approaches
land, a shoreline or a beach.
[0007] Sailboards can be similar to surfboards, but can be fitted
with a sail, which catches available wind currents to propel the
board, thus not relying solely on available water currents and/or
waves to provide the impetus for forward motion.
[0008] Often, in order to stabilize the direction, surfboards and
sailboards require a fin, i.e., a plate of triangular design, and
whose plane is arranged essentially parallel to the plane of the
direction of travel.
[0009] Surfboards and sailboards are generally made of wood, or a
plastic material, for example, epoxy resin,
acrylonitrile-butadiene-styrene (ABS) resin or similar materials,
which form the actual rump or body and surround a core made of
foamed material, such as polystyrene or polyurethane. Since, for
various reasons, the boards have to be designed to be as light as
possible, the actual plastic skin is not very thick.
[0010] U.S. Pat. No. 5,928,045 discloses a sports board having a
foam core, and a deck layer, a bottom layer and an outer rail,
which cover the foam core.
[0011] U.S. Pat. No. 3,337,886 discloses a surfboard having a core
of foam material and an outer skin or shell.
[0012] GB 961,612 discloses surfboards composed of an expanded
polystyrene plate with a plastic cover. The polystyrene material
used for this surfboard is "water repellent". The expanded
polystyrene plate is covered with plastic. Although this
combination provides a surfboard with water repellent
characteristics and an external surface to support the users, the
combination is not impact resistant.
[0013] EP 224 023 discloses a surfboard having a compound structure
where the foaming core is covered with a synthetic resin and a
thermoplastic material with a silver braid tissue sandwiched
in-between. The silver braid tissue provides a more rigid foam
structure.
[0014] FR 2 787 088 discloses a sandwich-type structure for a
surfboard. This surfboard includes a soft foam core such as
polystyrene and polyurethane between fiberglass and carbon. The
structure is mounted with an adhesive substance such as epoxy resin
and laminated polymers.
[0015] U.S. Pat. No. 5,275,860 discloses surf boards and body
boards where the board includes a core foam which is a closed pore
or closed cell foam to which is directly bonded an upper and lower
skin. To achieve a substantially high integrity bond, an
intermediate layer is composed of a mixture of the polymeric
material of the foam and the different polymeric material of the
skins. The foam is a polypropylene expanded bead foam while the
skins are high density polyethylene.
[0016] U.S. Pat. No. 5,944,570 discloses a surfboard which has a
prestressed center stringer with a foam core element located on
each side of the stringer to form a center core element.
[0017] U.S. Pat. No. 4,798,549 discloses a surfboard that includes
an elongated stringer with upper and lower surfaces curved
generally to the longitudinal profile of the surfboard, a passage
formed into and extending along the length of the stringer, outlet
ports spaced along the stringer, a fin box formed in the stringer
at the rear end thereof. The passage, ports, and fin box are
constructed and arranged for the introduction of at least one of
foam and steam therethrough for introduction into a space adjacent
to said stringer.
[0018] U.S. Pat. No. 4,850,913 discloses a sports board for
surfing, snow sledding, and other sports that has a shaped
polyethylene foam core to which a polyethylene film/polyethylene
foam sheet laminate is heat laminated over substantially all the
surfaces of the core.
[0019] U.S. Pat. No. 4,887,986 discloses surfboards and sail boards
that include an inflexible floating body having a stern and a prow;
two flexible side portions attached to the inflexible floating
body, one on either side thereof; and a mast foot located on the
inflexible floating body, where the flexible side portions are
incorporated into the flexible floating body from the stern to
about the range of the mast foot and the inflexible floating body
tapers between the flexible side portions in the direction of the
stern to become a narrow bridge that is narrower than each of the
flexible side portions.
[0020] U.S. Pat. No. 6,712,657 discloses body boards and surfboards
having a spine member longitudinally mounted between the two halves
of the board. Reinforcement members are mounted longitudinally and
transversally along the board blanks.
[0021] U.S. Patent Application Publication 2006/0270288 discloses a
process of wrapping a foam core surfboard shape with 1/4'' slick
foam skins via heat transfer. The heat transferred "foam stacked
rail configurations" allow "pinstripes" to outline the outer edges
of the board.
[0022] A body board is used by a rider to maneuver on ocean waves.
The rider typically holds one or both side rails of the body board
while the rider's hips, chest, knee, and/or foot are positioned on
the top deck of the body board. The combination of ocean surf, the
rider's weight, and the rider's directing the body board with the
hands, elbows, torso, knee and/or foot places enormous flex and
torsion stress on the body board. The flex and torsion stress tend
to distort the body board, and generally this is an undesirable
result because successful completion of maneuvers requires the body
board's responding adequately to the rider's steering. Force
applied to the body board that only distorts the board does not
help the rider in redirecting the board. Thus, a high degree of
stiffness of the body board is desirable.
[0023] On the other hand, simply making the body board to be very
rigid is not a practicable solution because of weight concerns and
because flex in the body board may be desirable along certain
sections of the board. For example, it may be desirable for the
board to be more flexible at a transverse line about a quarter of
the way aft of the nose and lead corners. Such flexibility allows
the rider to pull up the nose, distorting it above the plane of the
main deck of the body board to keep the nose and lead corners from
dropping under the water's surface in a dynamic situation where the
nose is being forced downwardly. However, in the forward quarter of
the board, it is generally considered desirable for the board to be
very stiff along a transverse line so that the rider's steering
inputs on one side of the board will effectively be transmitted to
the opposite side of the board and redirect the opposite side.
Notwithstanding these generalizations, variations in individual
riders' styles and preferences for body board performance
characteristics, as well as wide variations in surf conditions,
complicate the task of providing appropriate stiffening to a body
board.
[0024] In general, body boards can include a variable flexure
characteristic, e.g., needed flexure in the nose area for what is
known as "power turns" and strength in the mid and tail sections,
which may be required for speed. The nose section can be configured
to permit corner flexing or flexing along the entire nose section.
In general, the bottom skin is smooth, tough and scratch resistant
for speed over the water. The deck skin or upper surface of the
board is textured to provide relative slip resistance.
[0025] In addition to the above, there is a characteristic of a
body board known as "rocker". This generally refers to the bending
up from the centerline of the body board. There is overall rocker,
nose rocker and tail rocker. Rocker usually affects the ability of
the board to plane above the uneven surface of the water. There is
no "perfect" rocker but there is general agreement on what
constitutes a good rocker. Typically a good rocker involves a
gentle curve upward from about 1/3 back from the nose with a
resulting rise from the bottom of the board to about 11/2 inches at
the nose. The other 2/3 of the board should be flat or have a very
small amount of rise from about 1/3 back from the nose.
[0026] Body boards are typically constructed of a buoyant foam core
to which are attached an upper skin, a lower skin, and side rails.
The added skins and rails provide durable outer surfaces, and the
lower skin typically has a slick outer surface to speed the board
on the water.
[0027] U.S. Patent Application Publication 2003/0008575 discloses a
body board that includes a foam core with buoyancy to support a
rider in water. A substantially solid and rigid, generally planar
stiffening element is coupled to the core, for example by embedding
therein, and the element provides a resistance to flexing in
response to the rider's applying a bending force to the core. The
stiffening element can include a beam oriented in a direction
generally perpendicular to the longitudinal axis of the core, a
beam oriented in a direction generally parallel to the longitudinal
axis, and/or a beam oriented in a direction oblique to the
longitudinal axis. The resistance to flexing provided by the
stiffening element may increase in a continuously varying amount
over at least a portion of the foam core. The element may provide
the resistance along a first selected vector and a second selected
vector, wherein the second selected vector is not parallel to the
first.
[0028] A sled board is a sliding device that includes an elongate
member configured to slide on any sufficiently downward sloping,
slippery surface, such as snow, ice, grass, metal, or water on a
water slide with one or more riders in a sitting, kneeling, or
prone position.
[0029] U.S. Patent Application Publications 2003/0205872 and
2005/0035564 disclose a soft foam sled board prepared from a shaped
polyethylene foam core, and at least the bottom surface of the core
is covered by a slick, polyethylene film/polyethylene foam sheet
laminate which provides little frictional resistance between the
sled board and sliding surface.
[0030] A snow board is a sliding device that includes an elongate
member configured to slide on a snow-covered downward sloping
surface with one or more riders in a standing position.
[0031] U.S. Pat. No. 5,865,446 discloses a snow board that includes
a first section having an upper surface, a lower surface, an outer
end and an inner end, the outer end being upwardly curved to
facilitate movement of the first section over a surface in a first
direction; a second section having an upper surface, a lower
surface, an outer end and an inner end, the outer end being
upwardly curved to facilitate movement of the second section over
the surface in a second direction; a flexible connector for
connecting the inner end of the first section to the inner end of
the second section, the flexible connector being capable of
twisting and being flexible in both a horizontal and vertical
direction; a first binding for securing one of the user's feet to
the upper surface of the first section, the first binding being
fixedly secured to the first section: and a second binding for
securing the other foot of the user to the upper surface of the
second section, the second binding being fixedly secured to the
second section; whereby the user is able to facilitate the movement
of the snow board in either the first or the second direction. The
first and second sections of the snow board can each have a mid
section positioned between the inner and outer ends and the
mid-sections can be constructed from foam core or solid polymer
resins.
[0032] A skateboard is a narrow elongated wheeled platform adapted
for a rider to be transported in a standing position.
[0033] U.S. Pat. No. 5,716,562 discloses a method for making an
injection molded, foamed, composite material skateboard. The
skateboard body is formed of a composite material including a
foamed structural plastic mass including plural, elongate strands
of carbon fiber material distributed within the confines of the
mass. The skateboard body is formed by injection molding using a
thermoplastic such as nylon, polypropylene and polyethylene.
[0034] Sports boards that are lightweight are advantageous, as in
most cases, it is desirable that the rider not have to carry any
more weight than necessary. Additionally, in water applications,
the weight of the board can adversely affect the buoyancy of the
board.
[0035] Unfortunately, foam core boards utilizing polyurethane,
expanded polystyrene, and/or expanded polypropylene tend to take on
moisture when exposed to water making them heavier and less
desirable.
[0036] Additionally, in many applications for sports boards, it is
desirable for the board to have good flexibility, the ability of a
board to "spring" back to its original shape when deformed.
Flexibility can provide, for example, acceleration when surfing and
improved turning radius and acceleration when snowboarding.
[0037] Though flexibility is a desirable attribute, it has proved
elusive to build into a sports board, and typically requires time
consuming and expensive construction methods.
[0038] Thus, there is a need in the art for sports boards that are
light in weight, that do not take on water and that can provide
good flexibility characteristics in an economical fashion.
SUMMARY OF THE INVENTION
[0039] The present invention provides a sports board that includes
an elongate, water impervious, thermoplastic foam core having an
upper surface and an under surface; an upper layer covering at
least a portion of the upper surface; and an under layer covering
at least a portion of the under surface. The foam core is made of a
foamed material having a water absorption (measured according to
ASTM C-272) of less than 2 volume percent volume percent.
[0040] The present invention also provides a surfboard that
includes an elongate, water impervious, foam core comprising an
interpenetrating network of one or more polyolefins and one or more
polymers of vinyl aromatic monomers having and upper surface and an
under surface; an upper layer covering at least a portion of the
upper surface; and an under layer covering at least a portion of
the under surface. The foam core is made of a foamed material
having a water absorption (measured according to ASTM C-272) of
less than 2 volume percent volume percent.
[0041] A surfboard blank that includes an elongate, water
resistant, first portion comprising an expandable polymer matrix
having an inner edge, a lead end and a tail end; an elongate, water
resistant, second portion comprising an expandable polymer matrix
having an inner edge, a lead end and a tail end; and a stringer
disposed along and between the inner edges of the first portion and
the second portion and secured thereto. The expandable polymer
matrix contains one or more resins selected from interpolymers of a
polyolefin and in situ polymerized vinyl aromatic monomers, rubber
modified polystyrene, polyolefins, polystyrene modified rubber,
polyphenylene oxide, and combinations and blends thereof.
DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 shows a top plan view of a surfboard according to
embodiments of invention;
[0043] FIG. 2 shows a bottom plan view of a surfboard according to
embodiments of the invention;
[0044] FIG. 3 shows a side elevation view of a surfboard according
to embodiments of the invention;
[0045] FIG. 4 shows a cross sectional view of a surfboard according
to embodiments of the invention;
[0046] FIG. 5 shows a cross sectional view of a surfboard according
to embodiments of the invention;
[0047] FIG. 6 shows a top plan view of a surfboard according to
embodiments of the invention;
[0048] FIG. 7 shows a bottom plan view of a surfboard according to
embodiments of the invention;
[0049] FIG. 8 shows a side elevation view of a surfboard according
to embodiments of the invention;
[0050] FIG. 9 shows a cross sectional view of a surfboard according
to embodiments of the invention;
[0051] FIG. 10 shows a cross sectional view of a surfboard
according to embodiments of the invention;
[0052] FIG. 11 is a top plan view of a body board according to
embodiments of the invention;
[0053] FIG. 12 is a side elevation view of a body board according
to embodiments of the invention;
[0054] FIG. 13 is a cross-sectional view of a body board according
to embodiments of the invention;
[0055] FIG. 14 is a cross-sectional view of a body board according
to embodiments of the invention;
[0056] FIG. 15 is a top plan view of a water ski according to
embodiments of the invention;
[0057] FIG. 16 is a side elevation view of a water ski according to
embodiments of the invention;
[0058] FIG. 17 is a cross-sectional view of a water ski according
to embodiments of the invention;
[0059] FIG. 18 is a cross-sectional view of a water ski according
to embodiments of the invention;
[0060] FIG. 19 is a top plan view of a snowboard according to
embodiments of the invention;
[0061] FIG. 20 is a side elevation view of a snowboard according to
embodiments of the invention;
[0062] FIG. 21 is a cross-sectional view of a snowboard according
to embodiments of the invention;
[0063] FIG. 22 is a cross-sectional view of a snowboard according
to embodiments of the invention;
[0064] FIG. 23 is a top plan view of a snow ski according to
embodiments of the invention;
[0065] FIG. 24 is a side elevation view of a snow ski according to
embodiments of the invention;
[0066] FIG. 25 is a cross-sectional view of a snow ski according to
embodiments of the invention;
[0067] FIG. 26 is a cross-sectional view of a snow ski according to
embodiments of the invention;
[0068] FIG. 27 is a top plan view of a sled according to
embodiments of the invention;
[0069] FIG. 28 is a bottom plan view of a sled according to
embodiments of the invention;
[0070] FIG. 29 is a side elevation view of a sled according to
embodiments of the invention;
[0071] FIG. 30 is a cross-sectional view of a sled according to
embodiments of the invention;
[0072] FIG. 31 is a top plan view of a surfboard blank according to
embodiments of the invention;
[0073] FIG. 32 is a side elevation view of the surfboard blank of
FIG. 31;
[0074] FIG. 33 is a top plan view of a surfboard blank according to
embodiments of the invention;
[0075] FIG. 34 is a side elevation view of the surfboard blank of
FIG. 33;
[0076] FIG. 35 is a top plan view of a surfboard blank according to
embodiments of the invention; and
[0077] FIG. 36 is a side elevation view of the surfboard blank of
FIG. 35.
DETAILED DESCRIPTION OF THE INVENTION
[0078] For the purpose of the description hereinafter, the terms
"upper", "lower", "inner", "outer", "right", "left", "vertical",
"horizontal", "top", "bottom", and derivatives thereof, shall
relate to the invention as oriented in the drawing Figures.
However, it is to be understood that the invention may assume
alternate variations and step sequences except where expressly
specified to the contrary. It is also to be understood that the
specific devices and processes, illustrated in the attached
drawings and described in the following specification, is an
exemplary embodiment of the present invention. Hence, specific
dimensions and other physical characteristics related to the
embodiment disclosed herein are not to be considered as limiting
the invention. In describing the embodiments of the present
invention, reference will be made herein to the drawings in which
like numerals refer to like features of the invention.
[0079] Other than in the operating examples or where otherwise
indicated, all numbers or expressions referring to quantities of
ingredients, reaction conditions, etc. used in the specification
and claims are to be understood as modified in all instances by the
term "about". Accordingly, unless indicated to the contrary, the
numerical parameters set forth in the following specification and
attached claims are approximations that can vary depending upon the
desired properties, which the present invention desires to obtain.
At the very least, and not as an attempt to limit the application
of the doctrine of equivalents to the scope of the claims, each
numerical parameter should at least be construed in light of the
number of reported significant digits and by applying ordinary
rounding techniques.
[0080] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations,
the numerical values set forth in the specific examples are
reported as precisely as possible. Any numerical values, however,
inherently contain certain errors necessarily resulting from the
standard deviation found in their respective testing
measurements.
[0081] Also, it should be understood that any numerical range
recited herein is intended to include all sub-ranges subsumed
therein. For example, a range of "1 to 10" is intended to include
all sub-ranges between and including the recited minimum value of 1
and the recited maximum value of 10; that is, having a minimum
value equal to or greater than 1 and a maximum value of equal to or
less than 10. Because the disclosed numerical ranges are
continuous, they include every value between the minimum and
maximum values. Unless expressly indicated otherwise, the various
numerical ranges specified in this application are
approximations.
[0082] As used herein the term "surfboard" refers to an elongate
member configured to float, which is suitable for one or more
riders to use in a standing position to surf.
[0083] As used herein, the term "sailboard" refers to an elongate
member configured to float, which is or can be fitted with a sail
and is suitable for one or more riders to use in a standing
position to windsurf and the like.
[0084] As used herein the term "body board" refers to an elongate
member configured to float, which is used by a rider to maneuver on
ocean waves in a sitting, kneeling or prone position.
[0085] As used herein the term "wave board" refers to a small
roughly rectangular member configured to float, which is used by a
rider to maneuver on ocean waves in a prone position.
[0086] As used herein the term "sled board" refers to a sliding
device that includes an elongate member configured to slide on any
sufficiently downward sloping slippery surface, such as snow, ice,
grass, metal, or water on a water slide with one or more riders in
a sitting, kneeling, or prone position.
[0087] As used herein the term "snow board" refers to a sliding
device that includes an elongate member configured to slide on a
snow-covered downward sloping surface with one or more riders in a
standing position.
[0088] As used herein the term "skateboard" refers to a narrow
elongated wheeled platform adapted for one or more riders to be
transported in a standing position.
[0089] As used herein the term "snow ski" refers to a narrow,
generally rectangular sliding device used in pairs to slide on a
snow-covered downward sloping surface with a rider in a standing
position with one foot secured to each device.
[0090] As used herein the term "water ski" refers to a narrow
generally rectangular sliding device that can optionally be used in
pairs, to glide along the surface of water while being pulled by a
motorized water craft with a rider in a standing position with feet
secured to one or two of such devices.
[0091] As used herein the term "go-kart" refers to a rectangular
wheeled platform adapted for one or more riders to be transported
in a sitting, kneeling, or prone position.
[0092] As used herein, the term "expandable polymer matrix" refers
to a polymeric material in particulate or bead form that is
impregnated with a blowing agent such that when the particulates
and/or beads are exposed to heat, evaporation of the blowing agent
(as described below) effects the formation of a cellular structure
and/or an expanding cellular structure in the particulates and/or
beads causing the bead to expand and when the expanded beads are
placed in a mold and further exposed to heat, the beads can further
expand and the outer surfaces of the particulates and/or beads can
fuse together to form a continuous mass of polymeric material
conforming to the shape of the mold.
[0093] As used herein, the terms "expanded plastics", "prepuff",
"expanded resin beads" and "prefoam" refer to foamed thermoplastic
particles that have been impregnated with a blowing agent, at least
some of which has been subsequently removed (as a non-limiting
example heated and expanded followed by evaporation and diffusion
out of the bead) in a way that increases the volume of the
particles and accordingly decreases their bulk density.
[0094] As used herein, the term "thermoplastic" refers to materials
that are capable of softening, fusing, and/or modifying their shape
when heated and of hardening again when cooled.
[0095] As used herein, the term "polymer" is meant to encompass,
without limitation, homopolymers, copolymers and graft
copolymers.
[0096] As used herein, the term "polyolefin" refers to a polymer
prepared from at least one olefinic monomer, such as alpha
unsaturated C.sub.2-C.sub.32 linear or branched alkenes,
non-limiting examples of which include ethylene, propylene,
1-butene, 1-hexene and 1-octene.
[0097] As used herein, the term "polyethylene" refers to and
includes not only a homopolymer of ethylene, but also an ethylene
copolymer containing units of at least 50 mole %, in some cases at
least 70 mole %, and in other cases at least 80 mole % of an
ethylene unit and a corresponding proportion of units from a
monomer copolymerizable with ethylene, and blends containing at
least 50% by weight, in some cases at least 60% by weight, and in
other cases at least 75% by weight of an ethylene homopolymer or
copolymer with another polymer.
[0098] Non-limiting examples of monomers that can be copolymerized
with ethylene include vinyl acetate, vinyl chloride, propylene,
1-butene, 1-hexene, 1-octene, and (meth)acrylic acid and its
esters.
[0099] Polymers that can be blended with ethylene homopolymers or
copolymers include any polymer compatible with ethylene
homopolymers or copolymers. Non-limiting examples of polymers that
can be blended with ethylene homopolymers or copolymers include
polypropylene, polybutadiene, polyisoprene, polychloroprene,
chlorinated polyethylene, polyvinyl chloride, styrene/butadiene
copolymers, vinyl acetate/ethylene copolymers, styrenic polymers,
acrylonitrile/butadiene copolymers, styrene/butadiene/acrylonitrile
copolymers, and vinyl chloride/vinyl acetate copolymer.
[0100] As used herein, the term "styrenic polymers" refers to
homopolymers of styrenic monomers and copolymers of styrenic
monomers and another copolymerizable monomer, where the styrenic
monomers make up at least 50 mole percent of the monomeric units in
the copolymer. Non-limiting examples of styrenic monomers include
styrene, p-methyl styrene, .alpha.-methyl styrene, tertiary butyl
styrene, dimethyl styrene, dibromostyrene, nuclear brominated or
chlorinated derivatives thereof and combinations thereof.
Non-limiting examples of suitable copolymerizable monomers include
1,3-butadiene, C.sub.1-C.sub.32 linear, cyclic or branched alkyl
(meth)acrylates (specific non-limiting examples include butyl
(meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate, and
2-ethylhexyl (meth)acrylate), butyl acrylate, acrylonitrile, vinyl
acetate, alpha-methylethylene, divinyl benzene, maleic anhydride,
maleic acid, fumaric acid, C.sub.1-C.sub.12 linear, branched or
cyclic mono- and di-alkyl esters of maleic acid, C.sub.1-C.sub.12
linear, branched or cyclic mono- and di-alkyl esters of fumaric
acid, itaconic acid, C.sub.1-C.sub.12 linear, branched or cyclic
mono- and di-alkyl esters of itaconic acid, itaconic anhydride and
combinations thereof.
[0101] As used herein, the terms "(meth)acrylic" and
"(meth)acrylate" are meant to include both acrylic and methacrylic
acid derivatives, such as the corresponding alkyl esters often
referred to as acrylates and (meth)acrylates, which the term
"(meth)acrylate" is meant to encompass.
[0102] As used herein, the term "molding" refers to the shaping of
a pliable material to assume a new desired shape. Molding can
involve the use of specific molding tools such as male and female
molding tools, sculptured platens, and the like. It can also
include the use of specifically shaped core members including
compressible core members that are used to impart a desired shape
to at least a portion of a thermoplastic material.
[0103] As used herein, the term "rubber" refers to natural or
synthetic polymeric substances which have the ability to undergo
deformation under the influence of a force and regain their
original shape once the force is removed.
[0104] As used herein, the term "rubber modified polystyrene"
refers to styrenic polymers where the styrenic polymer constitutes
a continuous phase and the rubber constitutes a dispersed phase in
the resin.
[0105] As used herein, the term "polystyrene modified rubber"
refers to resins where the rubber constitutes a continuous phase
and the styrenic polymer constitutes a dispersed phase in the resin
as described in copending U.S. Patent Publication No. 2006-0276558
A1, the relevant portions of which are herein incorporated by
reference.
[0106] The present invention provides a sports board that includes
an elongate, water resistant or impervious, thermoplastic foam core
having and upper surface and an under surface; an upper layer
covering at least a portion of the upper surface; and an under
layer covering at least a portion of the under surface.
[0107] The thermoplastic foam core contains a foamed expandable
polymer matrix that is at least resistant or impervious to water.
The expandable polymer matrix contains one or more thermoplastic
resins. Suitable thermoplastic resins include, but are not limited
to an interpolymers of a polyolefin and in situ polymerized vinyl
aromatic monomers, rubber modified polystyrene, polystyrene
modified rubber, polyphenylene oxide, blends of polyolefins and at
least one other polymer, and combinations and blends thereof.
[0108] The thermoplastic resins can be in the form of beads,
pellets, granules, or other particles convenient for use in
expansion and molding operations.
[0109] In an embodiment of the invention, the thermoplastic resins
indicated above can be blended with and can include one or more
polymers selected from homopolymers of vinyl aromatic monomers;
copolymers of at least one vinyl aromatic monomer with one or more
of divinylbenzene, conjugated dienes, alkyl methacrylates, alkyl
acrylates, acrylonitrile, and/or maleic anhydride; polyolefins;
polycarbonates; polyesters; polyamides; natural rubbers; synthetic
rubbers; and combinations thereof.
[0110] In an particular embodiment of the invention, the
thermoplastic resins indicated above is a blend of one or more
polyolefins and one or more polymers selected from homopolymers of
vinyl aromatic monomers; copolymers of at least one vinyl aromatic
monomer with one or more of divinylbenzene, conjugated dienes,
alkyl methacrylates, alkyl acrylates, acrylonitrile, and/or maleic
anhydride; polycarbonates; polyesters; polyamides; natural rubbers;
synthetic rubbers; and combinations thereof.
[0111] In a particular aspects of this embodiment of the invention,
the expandable thermoplastics can include thermoplastic
homopolymers or copolymers selected from homopolymers derived from
vinyl aromatic monomers including styrene, isopropylstyrene,
alpha-methylstyrene, nuclear methylstyrenes, chlorostyrene,
tert-butylstyrene, and the like, as well as copolymers prepared by
the copolymerization of at least one vinyl aromatic monomer as
described above with one or more other monomers, non-limiting
examples being divinylbenzene, conjugated dienes (non-limiting
examples being butadiene, isoprene, 1,3- and 2,4-hexadiene), alkyl
methacrylates, alkyl acrylates, acrylonitrile, and maleic
anhydride, wherein the vinyl aromatic monomer is present in at
least 50% by weight of the copolymer. In an embodiment of the
invention, styrenic polymers are used, particularly polystyrene.
However, other suitable polymers can be included, such as
polyolefins (e.g., polyethylene, polypropylene), polycarbonates,
polyphenylene oxides, and mixtures thereof. In embodiments of the
invention, mixtures of the above-mentioned polymers can be
used.
[0112] As indicated above, the expandable polymer matrix can
include an interpolymer of a polyolefin and in situ polymerized
vinyl aromatic monomers and optionally other expandable
polymers.
[0113] In embodiments of the invention, the interpolymer of a
polyolefin and in situ polymerized vinyl aromatic monomers can be
one or more of those described in U.S. Pat. Nos. 3,959,189;
4,168,353; 4,303,756, 4,303,757 and 6,908,949, the relevant
portions of which are herein incorporated by reference. A
non-limiting example of such interpolymers that can be used in the
present invention include those available under the trade name
ARCEL.RTM., available from NOVA Chemicals Inc., Pittsburgh, Pa. and
PIOCELAN.RTM., available from Sekisui Plastics Co., Ltd., Tokyo,
Japan.
[0114] In embodiments of the invention, the interpolymer of a
polyolefin and in situ polymerized vinyl aromatic monomers is a
particle or resin bead, which is subsequently processed to form the
foam core of a sports board according to the present invention. The
interpolymer particles used in the invention include a polyolefin
and an in situ polymerized vinyl aromatic resin that form an
interpenetrating network of polyolefin and vinyl aromatic resin
particles. The interpolymer particles are impregnated with a
blowing agent and optionally, a plasticizer.
[0115] Such interpolymer particles can be obtained by processes
that include suspending polyolefin particles and vinyl aromatic
monomer or monomer mixtures in an aqueous suspension and
polymerizing the monomer or monomer mixtures inside the polyolefin
particles. Non-limiting examples of such processes are disclosed in
U.S. Pat. Nos. 3,959,189, 4,168,353 and 6,908,949.
[0116] In an embodiment of the invention, the polyolefin can
include one or more polyethylene resins selected from low-,
medium-, and high-density polyethylene; an ethylene vinyl acetate
copolymer; an ethylene/propylene copolymer; a blend of polyethylene
and polypropylene; a blend of polyethylene and an ethylene/vinyl
acetate copolymer; and a blend of polyethylene and an
ethylene/propylene copolymer. Ethylene-butyl acrylate copolymer and
ethylene-methyl methacrylate copolymer can also be used.
[0117] As indicated above, the thermoplastic resin of the polymer
matrix can include a polystyrene modified rubber where the rubber
constitutes a continuous phase and the styrenic polymer constitutes
a dispersed phase in the resin as described in copending U.S.
Patent Publication No. 2006-0276558, the relevant portions of which
are herein incorporated by reference.
[0118] In some embodiments of the invention, the expandable polymer
matrix can include mixtures and combinations of the above-described
thermoplastic resins. In other embodiments, the above-described
thermoplastic resins or combinations of thermoplastic resins can be
used in mixtures and combinations with other polymers. The mixtures
and combinations can be used to provide particular properties to
the expandable polymer matrix and/or foam core, such as water
impermeability, flexural strength, elastic modulus, toughness,
and/or tear strength.
[0119] In particular embodiments of the invention, the expandable
polymer matrix can contain 100% interpolymers of a polyolefin and
in situ polymerized vinyl aromatic monomers, but can also contain
up to 99%, in some cases up to 95%, in other cases up to 90%, in
some instances up to 80% and in other instances up to 75% based on
the weight of the expandable polymer matrix of interpolymers of a
polyolefin and in situ polymerized vinyl aromatic monomers. Also,
the expandable polymer matrix can contain at least 25%, in some
cases at least 30%, in other cases at least 40% and in some
instances at least 50% based on the weight of the expandable
polymer matrix of interpolymers of a polyolefin and in situ
polymerized vinyl aromatic monomers. The amount of interpolymers of
a polyolefin and in situ polymerized vinyl aromatic monomers in the
expandable polymer matrix can be any value or range between any of
the values recited above.
[0120] When other expandable polymers are included in the
expandable polymer matrix with the interpolymers, the other
expandable polymers can be present at a level of at least 1%, in
some cases at least 5%, in other cases at least 10%, in some
instances at least 20% and in other instances at least 25% based on
the weight of the expandable polymer matrix. Also, the other
expandable polymers can be present in the expandable polymer matrix
at a level of up to 75%, in some cases up to 70%, in other cases up
to 60% and in some instances up to 50% based on the weight of the
expandable polymer matrix. The other expandable polymers can be
included in the expandable polymer matrix at any level or range
between any of the values recited above.
[0121] In other particular embodiments of the invention, the
expandable polymer matrix can contain 100% polystyrene modified
rubber, but can also contain up to 99%, in some cases up to 95%, in
other cases up to 90%, in some instances up to 80% and in other
instances up to 75% based on the weight of the expandable polymer
matrix of polystyrene modified rubber. Also, the expandable polymer
matrix can contain at least 25%, in some cases at least 30%, in
other cases at least 40% and in some instances at least 50% based
on the weight of the expandable polymer matrix of polystyrene
modified rubber. The amount of polystyrene modified rubber in the
expandable polymer matrix can be any value or range between any of
the values recited above.
[0122] When other expandable polymers are included in the
expandable polymer matrix with the polystyrene modified rubber, the
other expandable polymers can be present at a level of at least 1%,
in some cases at least 5%, in other cases at least 10%, in some
instances at least 20% and in other instances at least 25% based on
the weight of the expandable polymer matrix. Also, the other
expandable polymers can be present in the expandable polymer matrix
at a level of up to 75%, in some cases up to 70%, in other cases up
to 60% and in some instances up to 50% based on the weight of the
expandable polymer matrix. The other expandable polymers can be
included in the expandable polymer matrix at any level or range
between any of the values recited above.
[0123] In the present invention, the thermoplastic resins can be
particles polymerized in a suspension process, which are
essentially spherical resin beads useful for making expandable
thermoplastic particles. However, polymers derived from solution
and bulk polymerization techniques that are extruded and cut into
particle sized resin bead sections can also be used.
[0124] In an embodiment of the invention, thermoplastic resin beads
(unexpanded) containing any of resins, polymers and/or polymer
compositions described herein can have a particle size of at least
0.2, in some situations at least 0.33, in some cases at least 0.35,
in other cases at least 0.4, in some instances at least 0.45 and in
other instances at least 0.5 mm. Also, the resin beads can have a
particle size of up to 3, in some instances up to 2, in other
instances up to 2.5, in some cases up to 2.25, in other cases up to
2, in some situations up to 1.5 and in other situations up to 1 mm.
The resin beads used in this embodiment can be any value or can
range between any of the values recited above.
[0125] The expanded impregnated thermoplastic resin beads can be
expanded plastics, prepuff, and/or expanded resin beads as used in
the present invention.
[0126] The expandable thermoplastic particles or resin beads can
optionally be impregnated using any conventional method with a
suitable blowing agent. As a non-limiting example, the impregnation
can be achieved by adding the blowing agent to the aqueous
suspension during the polymerization of the polymer, or
alternatively by re-suspending the polymer particles in an aqueous
medium and then incorporating the blowing agent as taught in U.S.
Pat. No. 2,983,692. Any gaseous material or material which will
produce gases on heating can be used as the blowing agent.
Conventional blowing agents include aliphatic hydrocarbons
containing 4 to 6 carbon atoms in the molecule, such as butanes,
pentanes, hexanes, and the halogenated hydrocarbons, e.g., CFC's
and HCFC's, which boil at a temperature below the softening point
of the polymer chosen. Mixtures of these aliphatic hydrocarbon
blowing agents can also be used.
[0127] Alternatively, water can be blended with these aliphatic
hydrocarbons blowing agents or water can be used as the sole
blowing agent as taught in U.S. Pat. Nos. 6,127,439; 6,160,027; and
6,242,540 in these patents, water-retaining agents are used. The
weight percentage of water for use as the blowing agent can range
from 1 to 20%. The texts of U.S. Pat. Nos. 6,127,439, 6,160,027 and
6,242,540 are incorporated herein by reference.
[0128] The impregnated thermoplastic resin beads are optionally
expanded to a bulk density of at least 0.5 lb/ft.sup.3 (0.008
g/cc), in some cases, at least 1.25 lb/ft.sup.3 (0.02 g/cc), in
other cases at least 1.5 lb/ft.sup.3 (0.024 g/cc), in some
situations, at least 1.75 lb/ft.sup.3 (0.028 g/cc), in some
circumstances, at least 2 lb/ft.sup.3 (0.032 g/cc) in other
circumstances at least 3 lb/ft.sup.3 (0.048 g/cc), and in
particular circumstances at least 3.25 lb/ft.sup.3 (0.052 g/cc) or
3.5 lb/ft.sup.3 (0.056 g/cc) thus forming pre-expanded
thermoplastic beads or particles. When non-expanded resin beads are
used, higher bulk density beads can be used. As such, the bulk
density can be as high as 40 lb/ft.sup.3 (0.64 g/cc) and when only
slightly expanded up to 30 lb/ft.sup.3 (0.48 g/cc), in some cases
up to 20 lb/ft.sup.3 (0.32 g/cc), in other cases, up to 10
lb/ft.sup.3 (0.16 g/cc) and in some instances up to 7.5 lb/ft.sup.3
(0.12 g/cc). The bulk density of the thermoplastic particles can be
any value or range between any of the values recited above.
[0129] The expansion step is conventionally carried out by heating
the impregnated beads via any conventional heating medium, such as
steam, hot air, hot water, or radiant heat. One generally accepted
method for accomplishing the pre-expansion of impregnated
thermoplastic particles is taught in U.S. Pat. No. 3,023,175.
[0130] The impregnated resin beads can be foamed cellular polymer
particles as taught in U.S. Patent Publication No. 2002-0117769,
the teachings of which are incorporated herein by reference. The
foamed cellular particles can be any of the resins and/or polymers
described above that can be expanded and contain a volatile blowing
agent at a level of less than 14 wt %, in some situations less than
6 wt. %, in some cases ranging from about 2 wt. % to about 5 wt. %,
and in other cases ranging from about 2.5 wt. % to about 3.5 wt. %
based on the weight of the polymer.
[0131] When interpolymer resins are included in the expandable
polymer matrix, the amount of polyolefin in the interpolymer resin
of the invention can be at least 20%, in some cases at least 25%,
and in other cases at least 30% and can be up to 80%, in some cases
up to 70%, in other cases up to 60% and in some instances up to
55%, by weight based on the Weight of the interpolymer resin
particles. The amount of polyolefin in the interpolymer resin can
be any value or range between any of the values recited above.
[0132] The amount of polymerized vinyl aromatic resin in the
interpolymer resin of the invention can be at least 20%, in some
cases at least 30%, in other cases at least 40% and in some
instances at least 45% and can be up to 80%, in some cases up to
75% and in other cases up to 70%, by weight based on the weight of
the interpolymer resin particles. The amount of polymerized vinyl
aromatic resin in the interpolymer resin can be any value or range
between any of the values recited above.
[0133] The vinyl aromatic resin in the interpolymer resin can be
made up of polymerized vinyl aromatic monomers or the resin can be
a copolymer containing monomeric units from vinyl aromatic monomers
and copolymerizable comonomers. Non-limiting examples of vinyl
aromatic monomers that can be used in the invention include
styrene, alpha-methylstyrene, ethylstyrene, chlorostyrene,
bromostyrene, vinyltoluene, vinylbenzene, and isopropylxylene.
These monomers may be used either alone or in admixture.
[0134] Non-limiting examples of copolymerizable comonomers include
1,3-butadiene, C.sub.1-C.sub.32 linear, cyclic or branched alkyl
(meth)acrylates (specific non-limiting examples include butyl
(meth)acrylate, ethyl (meth)acrylate and 2-ethylhexyl
(meth)acrylate), acrylonitrile, vinyl acetate,
alpha-methylethylene, divinyl benzene, maleic anhydride, itaconic
anhydride, dimethyl maleate and diethyl maleate.
[0135] Non-limiting examples of vinyl aromatic copolymers that can
be used in the interpolymer resin of invention include those
disclosed in U.S. Pat. No. 4,049,594. Specific non-limiting
examples of suitable vinyl aromatic copolymers include copolymers
containing repeat units from polymerizing styrene and repeat units
from polymerizing one or monomers selected from 1,3-butadiene,
C.sub.1-C.sub.32 linear, cyclic or branched alkyl (meth)acrylates
(specific non-limiting examples including butyl (meth)acrylate,
ethyl (meth)acrylate and 2-ethylhexyl (meth)acrylate),
acrylonitrile, vinyl acetate, alpha-methylethylene, divinyl
benzene, maleic anhydride, itaconic anhydride, dimethyl maleate and
diethyl maleate.
[0136] In particular embodiments of the invention, the vinyl
aromatic resin in the interpolymer resin includes polystyrene or
styrene-butyl acrylate copolymers.
[0137] In embodiments of the invention, the interpolymer resin
particles are formed as follows: The polyolefin particles are
dispersed in an aqueous medium prepared by adding 0.01 to 5%, in
some cases 2 to 3%, by weight based on the weight of the water of a
suspending agent such as water soluble high molecular weight
materials, e.g., polyvinyl alcohol or methyl cellulose or slightly
water soluble inorganic materials, e.g., calcium phosphate or
magnesium pyrophosphate and soap, such as sodium dodecyl benzene
sulfonate, and the vinyl aromatic monomers are added to the
suspension and polymerized inside the polyolefin particles.
[0138] Any conventionally known and commonly used suspending agents
for polymerization of vinyl aromatic monomers can be employed.
These agents are well known in the art and can be freely selected
by one skilled in the art. Initially, the water is in an amount
generally from 0.7 to 5, preferably 3 to 5 times that of the
starting polyolefin particles employed in the aqueous suspension,
on a weight basis, and gradually the ratio of the polymer particles
to the water may reach around 1:1.
[0139] The polymerization of the vinyl aromatic monomers, which are
absorbed in the polyolefin particles, is carried out using
initiators.
[0140] The initiators suitable for suspension polymerization of the
vinyl aromatic monomers are generally used in an amount of about
0.05 to 2 percent by weight, in some cases 0.1 to 1 percent by
weight, based on the weight of the vinyl aromatic monomer.
Non-limiting examples of suitable initiators include organic
peroxides such as benzoyl peroxide, lauroyl peroxide, t-butyl
perbenzoate and t-butyl perpivalate and azo compounds such as
azobiisobutylonitrile and azobidimethylvaleronitrile.
[0141] These initiators can be used alone or two or more initiators
can be used in combination. In many cases, the initiators are
dissolved in the vinyl aromatic monomers, which are to be absorbed
in the polyolefin particles. In other cases, the initiator can be
dissolved in a solvent, such as toluene, benzene, and
1,2-dichloropropane.
[0142] When the in situ polymerization of the vinyl aromatic
monomers is completed, the polymerized vinyl aromatic resin is
uniformly dispersed inside the polyolefin particles.
[0143] In many cases, the polyolefin particles are cross-linked.
The cross-linking can be accomplished simultaneously with the
polymerization of the vinyl aromatic monomer in the polyolefin
particles, and before impregnation of the blowing agent and/or
plasticizer. For this purpose, cross-linking agents are used. Such
cross-linking agents include, but are not limited to
di-t-butyl-peroxide, t-butyl-cumylperoxide, dicumyl-peroxide,
.alpha.,.alpha.-bis-(t-butylperoxy)-p-diisopropylbenzene,
2,5-dimethyl-2,5-di-(t-butylperoxy)-hexyne-3,2,5-dimethyl-2,5-di-(benzoyl-
peroxy)-hexane and t-butyl-peroxyisopropyl-carbonate. These
cross-linking agents are absorbed in the polyolefin particles
together with the vinyl aromatic monomers by dissolving the
cross-linking agent in an amount of about 0.1 to 2 weight % and in
some cases 0.5 to 1 weight %, based on the weight of the polyolefin
particles suspended in water. Further details of the cross-linking
agents and the manner for absorbing the cross-linking agents into
the polyolefin particles are provided in U.S. Pat. No.
3,959,189.
[0144] The interpolymer particles are acidified, dewatered,
screened, and subsequently charged to a second reactor where the
particles are impregnated with the blowing agent and/or
plasticizer.
[0145] The impregnation step can be carried out by suspending the
interpolymer particles in an aqueous medium, adding the blowing
agent and/or plasticizer to the resulting suspension, and stirring
at a temperature of, preferably, about 40.degree. C. degrees to
80.degree. C. The blowing agent and/or plasticizer can be blended
together and then added to the interpolymer particles or can be
added to the interpolymer particles separately.
[0146] Alternatively, the blowing agent and/or plasticizer can be
added to the first reactor during or after the polymerization
process.
[0147] The above processes describe a wet process for impregnation
of the interpolymer particles. Alternatively, the interpolymer
particles can be impregnated via an anhydrous process similar to
that taught in Column 4, lines 20-36 of U.S. Pat. No.
4,429,059.
[0148] When polystyrene modified rubber resins are included in the
expandable polymer matrix, these resins can be made by forming a
dispersion of organic droplets by pressure atomizing an organic
liquid mixture below the free surface of an aqueous phase, which
can be stationary or flowing, or by applying mechanical agitation.
The organic mixture typically contains an organic solution that
includes one or more elastomeric polymers and/or one or more
polyolefins dissolved in a monomer solution containing one or more
styrenic monomers. The dispersed organic droplets typically have an
average diameter of from about 0.001 mm to about 10 mm. The
monomers are typically polymerized, using initiators as described
above, in the dispersed organic droplets in a low shear flow
pattern to form unexpanded polymer beads. In many cases, the
organic mixture has a density of .+-.20% of the density of the
aqueous phase and the dispersed organic droplets make up from 0.01
to 60 volume percent of the total volume of the organic and aqueous
liquids.
[0149] In some embodiments, the low shear flow pattern is a
controlled low turbulence flow pattern created, without mechanical
agitation, by continuously or periodically injecting at gauge
pressure up to 15 bar into selected parts of the reactor one or
more streams of a gas inert to the reactor contents and immiscible
with the reactor contents. The gas can be injected into the aqueous
phase at a gauge pressure less than 3 bar and can form one or more
streams of bubbles having diameters substantially larger than the
average size of the atomized organic droplets.
[0150] In some embodiments, the low shear flow pattern is provided
by mechanical agitation.
[0151] Typically, the unexpanded polystyrene modified rubber resin
beads have a continuous phase and a dispersed phase and the
continuous phase includes the elastomeric polymers and/or
polyolefins in a crosslinked web morphology. The continuous phase
can also include elastomeric polymers and/or polyolefins in a
morphology that includes threads having a large aspect ratio, which
are optionally at least partially crosslinked and/or connected via
locally formed branches and/or an interconnected mesh
structure.
[0152] In many embodiments, the organic mixture contains from about
5 to about 50 wt. %, based on the weight of the organic mixture, of
one or more elastomeric polymers and/or one or more polyolefins and
from about 95 to about 50 wt. % of a monomer solution that includes
one or more styrenic monomers, where the elastomeric polymers
and/or one or more polyolefins are soluble in the monomer
solution.
[0153] In embodiments of the invention, the elastomeric polymers
can be selected from homopolymers of butadiene or isoprene, and
random, block, AB diblock, or ABA triblock copolymers of a
conjugated diene with an aryl monomer and/or (meth)acrylonitrile
and random, alternating or block copolymers of ethylene and vinyl
acetate.
[0154] In some embodiments of the invention, the elastomeric
polymers include one or more block copolymers selected from diblock
and triblock copolymers of styrene-butadiene,
styrene-butadiene-styrene, styrene-isoprene,
styrene-isoprene-styrene, ethylene-vinyl acetate, partially
hydrogenated styrene-isoprene-styrene and combinations thereof. In
other embodiments of the invention, the elastomeric polymers
include one or more copolymers containing repeat units from the
polymerization of one or more conjugated diene and at least one
unsaturated nitrile selected from acrylonitrile and
methacrylonitrile.
[0155] In an embodiment of the invention, the blowing agent can be
dosed to the expandable polymer matrix in an extruder to produce
resin pellets or beads. The extruder acts to mix the blowing agent
into the expandable polymer matrix prior to extruding a strand of
the mixture. The strand can be cut into bead or pellet lengths
using an appropriate device, a non-limiting example being an
underwater face cutter.
[0156] The particles and/or beads of the expandable polymer matrix
according to the invention can also contain other additives known
in the art, non-limiting examples including nucleating agents,
anti-static additives; flame retardants; colorants or dyes; filler
materials and combinations thereof. Other additives can also
include chain transfer agents, non-limiting examples including
C.sub.2-15 alkyl mercaptans, such as n-dodecyl mercaptan, t-dodecyl
mercaptan, t-butyl mercaptan and n-butyl mercaptan, and other
agents such as pentaphenyl ethane and the dimer of alpha-methyl
styrene. Other additives can further include nucleating agents,
non-limiting examples including polyolefin waxes, i.e.,
polyethylene waxes.
[0157] The resulting expandable polymer matrix is used as a raw
material in producing foam cores and/or blanks in the present
sports boards. The blowing agent and/or plasticizers are introduced
into the expandable polymer matrix resin particles to form foamable
or expandable particles or resin beads, which in turn, are used to
mold foam cores.
[0158] The blowing agent should have a boiling point lower than the
softening point of the polyolefin and should be gaseous or liquid
at room temperature (about 20 to 30.degree. C.) and normal pressure
(about atmospheric).
[0159] Blowing agents are well known in the art and generally have
boiling points ranging from -42.degree. C. to 80.degree. C., more
generally, from -10.degree. C. to 36.degree. C. Suitable
hydrocarbon blowing agents include, but are not limited to
aliphatic hydrocarbons such as n-propane, n-butane, iso-butane,
n-pentane, iso-pentane, n-hexane, and neopentane, cycloaliphatic
hydrocarbons such as cyclobutane and cyclopentane, and halogenated
hydrocarbons such as methyl chloride, ethyl chloride, methylene
chloride, trichlorofluoromethane, dichlorofluoromethane,
dichlorodifluormethane, chlorodifluoromethane and
dichlorotetrafluoroethane, etc. These blowing agents can be used
alone or as mixtures. If n-butane, ethyl chloride, and
dichlorotetrafluoroethane, which are gaseous at room temperature
and normal pressure, are used as a mixture, it is possible to
achieve foaming to a low bulk density. Specific types of volatile
blowing agents are taught in U.S. Pat. No. 3,959,180. In particular
embodiments of the invention, the blowing agent is selected from
n-pentane, iso-pentane, neopentane, cylcopentane, and mixtures
thereof.
[0160] The amount of the blowing agent ranges from about 1.5% to
about 20% by weight, in some cases, about 1.5% to 15% by weight,
and, in other cases, from 5% to 15% by weight, based on the weight
of the expandable polymer matrix.
[0161] A plasticizer can be used in combination with the blowing
agent and as stated herein above and acts as a blowing aid in the
invention.
[0162] Suitable plasticizers include, but are not limited to
benzene, toluene, limonene, linear, branched or cyclic C.sub.5 to
C.sub.20 alkanes, white oil, linear, branched or cyclic C.sub.1 to
C.sub.20 dialkylphthalates, styrene, oligomers of styrene,
oligomers of (meth)acrylates having a glass transition temperature
less than polystyrene, and combinations thereof.
[0163] In a particular embodiment of the invention, the plasticizer
includes limonene, a mono-terpene hydrocarbon existing widely in
the plant world. The known types are d-limonene, l-limonene, and
dl-limonene. D-limonene is contained in the skin of citrus fruits
and is used in food additives as a fragrant agent; its boiling
point is about 176.degree. C.; and its flammability is low.
D-limonene is a colorless liquid, has a pleasant orange-like aroma,
is approved as a food additive, and is widely used as a raw
material of perfume. Limonene is not a hazardous air pollutant.
[0164] The amount of plasticizer can range from about 0.1 to 5
parts and in some cases from about 0.1 to about 1 part, by weight
per 100 parts by weight of the expandable polymer matrix.
[0165] In many embodiments of the invention, the pre-expanded beads
or particles containing the expandable polymer matrix are molded
into a foam core shape of desired dimensions by adding pre-expanded
particles or beads after four to 48 hours of ageing to completely
fill a mold of the desired shape and dimensions and molding in a
steam molding press. When steam is applied uniformly to the
pre-expanded particles or beads, good fusion between beads is
accomplished. When heat is also applied from the mold and/or mold
press, a skin can be formed on the outer surface of the molded foam
core.
[0166] The skin that is formed during molding provides a surface
that readily accepts paint as well as laminating resins.
[0167] In prior art methods, the pre-expanded beads or particles
are molded into a generally rectangular shape mold. The foam core
is then prepared by cutting the general foam core shape into the
block molded foam and then shaping the desired curvature to provide
the foam core. This method is typically used in the prior art and
results in any skin of the molded part being removed and the fused
cell structure of the foam core being severely disrupted. This
method results in significantly higher water absorption in the foam
core as well as incompatibility with paint and laminating resins.
The latter typically results in a non-uniform or wavy surface in
the sports board, which is aesthetically undesirable and makes the
sports board less aerodynamic.
[0168] In embodiments of the invention, these problems have been
overcome by directly molding the foam core into its desired shape
as described above to form a skin and/or by applying a sealant to
the damaged surface created by cutting in the foam core shape.
[0169] Any sealant coating can be used that provides water
repellant properties to the surface of the foam core and provides a
surface that accepts laminating resins with little to no wrinkling
or other surface deformation. Suitable sealants are formulations
that include, but are not limited to, ethylene-vinyl acetate
copolymers, ethylene-vinyl alcohol copolymers, ethylene-acrylic
acid copolymers, styrene-butadiene polymers, styrene-isoprene
polymers; styrene-butadiene-styrene block polymers;
styrene-isoprene-styrene block polymers; and hydrogenated resins
thereof and combinations thereof.
[0170] Other materials that can be used as or as part of the
sealant, in some instances, include joint compound, gypsum paste,
polyurethanes, styrenic block copolymers, polypropylene, and
polyethylene.
[0171] In some embodiments, the sealant can be multilayered,
including layers that contain any of the materials indicated above.
Having one or more layers and the composition of those layers is
determined based on the composition of the foam core and the
composition of the upper layer covering and under layer covering.
As a non-limiting example, sealant can include three components, a
thermoplastic polyolefin; a thermoplastic styrenic polymer; and a
styrenic block copolymer.
[0172] In some instances, the sealant includes film structures
containing from 35 to 65 weight % of thermoplastic olefin, in some
cases, from 55 to 60 weight %; from 10 to 30 weight % thermoplastic
styrenic polymer, in some cases, from 15 to 20 weight %, with the
balance being a styrenic block copolymer.
[0173] In particular instances, the sealant can include from 20 to
60 weight % polypropylene, in some cases, 40 to 50 weight %; from
20 to 60 weight % polystyrene, in some cases, from 40 to 50 weight
%, with the balance being a styrenic block copolymer.
[0174] The styrenic block copolymer used in the sealant can be a
copolymer of at least one vinyl aromatic monomer and at least one
other olefin, diolefin and/or diene monomer. In particular
embodiments, the styrene block copolymers can contain blocks of
styrene and blocks of butadiene with from about 35 to 55 weight %
bound styrene and a number average molecular weight (determined
using gel permeation chromatography with polystyrene standards) of
from about 50,000 to about 100,000. Non-limiting example of
suitable styrenic block copolymers are those available under the
trademark KRATON.RTM. from KRATON Polymers U.S. L.L.C. of Houston,
Tex.
[0175] In some embodiments, the sealant includes multilayer
structures that contain at least three layers, a thermoplastic
polyolefin layer (TPO); a thermoplastic vinyl aromatic layer (TVA);
and a tie layer (TL) which is located between the TLO layer and the
TVA layer. This can be described as a TPO/TL/TVA structure. In some
specific embodiments, the sealant can include film structures
containing five layers, with the TVA layer being the core layer, as
a non-limiting example, a five layer structure can be described as
TPO/TL/TVA/TL/TPO.
[0176] When the sealant includes multilayer films, in many cases,
the sealant contains about 5 to 25 weight % of tie layer material
(based on the total weight of the multilayer structure). The tie
layers can be used in amounts of from 5 to 10 weight % when
preparing sheet structures, though it is possible to prepare useful
structures, which contain less than 1% tie layer material. The
amount of material used in the other layers can be widely varied to
suit different end use. As a non-limiting example, a multilayer
film containing similar amounts of polyolefin and thermoplastic
styrenic polymer (e.g., from 10 to 20 weight % "tie layer" and
40-50 weight % in each of the TPO and TVA layers.
[0177] It is also within the scope of the invention to pre-mix the
tie layer material with a part of the material used for one of the
outer layers. This method can be used when only a very small weight
% of the overall structure is contained in either the TPO layer of
the TVA layer.
[0178] In embodiments of the invention, the foam cores described
herein have a measured water absorption (measured according to ASTM
C-272) of less than 2, in some cases, less than 1, and, in other
cases, less than 0.5 volume percent determined on a sample molded
to a density of from 1.5 to 2.5 lb/ft.sup.3 (0.024 to 0.04
g/cc).
[0179] In other embodiments of the invention, the foam cores
described herein are made from materials that have a flexural
strength at 5% strain (measured according to ASTM C-203) of at
least 20 psi, in some cases, at least 25 psi and, in other cases,
at least 30 psi at a molded density of about 1.5 lb/ft3 (0.024
g/cc); at least 30 psi, in some cases, at least 35 psi and, in
other cases, at least 40 psi at a molded density of about 1.75
lb/ft3 (0.028 g/cc); at least 40 psi, in some cases, at least 45
psi and, in other cases, at least 50 psi at a molded density of
about 2 lb/ft3 (0.032 g/cc); and at least 60 psi, in some cases, at
least 65 psi and, in other cases, at least 70 psi at a molded
density of about 2.25 lb/ft3 (0.036 g/cc).
[0180] In additional embodiments of the invention, the foam cores
described herein are made from materials that have a tensile
strength (measured according to ASTM D-3575-T) of at least 25 psi,
in some cases, at least 30 psi and, in other cases, at least 35 psi
at a molded density of about 1.5 lb/ft.sup.3 (0.024 g/cc); at least
40 psi, in some cases, at least 45 psi and, in other cases, at
least 50 psi at a molded density of about 1.75 lb/ft.sup.3 (0.028
g/cc); at least 55 psi, in some cases, at least 60 psi and, in
other cases, at least 65 psi at a molded density of about 2
lb/ft.sup.3 (0.032 g/cc); and at least 75 psi, in some cases, at
least 80 psi and, in other cases, at least 85 psi at a molded
density of about 2.25 lb/ft.sup.3 (0.036 g/cc).
[0181] In additional embodiments of the invention, the foam cores
described herein are made from materials that have a foam tear
strength (measured according to ASTM D-3575-G) of at least 5 lb/in,
in some cases, at least 5.5 lb/in and, in other cases, at least 6
lb/in at a molded density of about 1.2 lb/ft.sup.3 (0.019 g/cc); at
least 9 lb/in, in some cases, at least 10 lb/in and, in other
cases, at least 11 lb/in at a molded density of about 1.5
lb/ft.sup.3 (0.024 g/cc); at least 12 lb/in, in some cases, at
least 13 lb/in and, in other cases, at least 14 lb/in at a molded
density of about 1.75 lb/ft.sup.3 (0.028 g/cc); at least 15 lb/in,
in some cases, at least 17 lb/in and, in other cases, at least 18
lb/in at a molded density of about 2 lb/ft.sup.3 (0.032 g/cc); and
at least 19 lb/in, in some cases, at least 20 lb/in and, in other
cases, at least 22 lb/in at a molded density of about 2.25
lb/ft.sup.3 (0.036 g/cc).
[0182] Advantageously, the foam cores described herein have
improved water repellant properties compared to expanded
polystyrene foam cores in the prior art in that they absorb much
less moisture and, therefore, do not take on undesirable weight
when exposed to water.
[0183] Additionally, the foam cores described herein have higher
tensile strength compared to expanded polyethylene or expanded
polypropylene foam cores of the same density so the present foam
cores are less likely to break during use.
[0184] Once the foam core has been made, an upper layer covering at
least a portion of the upper surface of the foam core and an under
layer covering at least a portion of the under surface of the foam
core are applied.
[0185] In embodiments of the invention, upper layer covering and
under layer covering include fibrous mats or fibrous fabric. The
mats or fabric can be conventional and contain fibers such as glass
fibers, aramide fibers, polyamide fibers, carbon fibers, silicon
carbide fibers, composite fibers, metal fibers, fiberglass, and
combinations thereof as well as fabric containing the
above-mentioned fibers, and fabric containing combinations of the
above-mentioned fibers.
[0186] When the prefabricated foam core has had one or more fibrous
layers applied as the upper layer covering and/or under layer
covering, a laminating resin is poured onto the fibrous mats at the
upper and/or under surfaces of the foam core. The laminating resin
can then be allowed to cure and harden, securing the fibrous
layer(s) of the upper layer covering and/or under layer covering to
the foam core.
[0187] In embodiments of the invention, after the laminating resin
has been applied, the thus treated foam core or blank is inserted
in a lower mold segment of a mold press in which the fibrous
layer(s) with laminating resin is held by vacuum, and the mold
press is closed. The pressure of the press causes the laminating
resin to be completely distributed in the space between the foam
core and the fibrous layer(s) and cures to form a closed
fiber-reinforced shell, which comes into intimate connection with
the foam core. The curing step can take place at a molding tool
temperature of at least about 80.degree. C. and for at least about
5 minutes.
[0188] After curing, the projecting film edges of the laminated
foam core can be trimmed. Thereafter, the cut faces can optionally
be sealed.
[0189] The laminating resin used to saturate the fibrous layer(s)
is typically a resin system-catalyst component system that includes
a resin system, a cure catalyst, and optionally filler
materials.
[0190] In embodiments of the invention, the laminating resin can be
a polyurethane formulation that includes a polyalcohol component
and an isocyanate component; an epoxy formulation that includes an
epoxy containing component and a reactive component such as a
polyalcohol component; a curable polyester formulation that
includes an unsaturated polyester resin component and a peroxide
component, non-limiting examples of suitable peroxides include
methyl ethyl ketone peroxide, hydrogen peroxide, benzoyl peroxide,
lauroyl peroxide, t-butyl perbenzoate, t-butyl perpivalate
di-t-butyl-peroxide, t-butyl-cumylperoxide, dicumyl-peroxide,
.alpha.,.alpha.-bis-(t-butylperoxy)-p-diisopropylbenzene,
2,5-dimethyl-2,5-di-(t-butylperoxy)-hexane-3,2,5-dimethyl-2,5-di-(benzoyl-
peroxy)-hexane and t-butyl-peroxyisopropyl-carbonate; a mixture of
dimethyl phthalate and an ester plasticizer and methyl ethyl ketone
peroxide second component; acrylic unsaturated polyester resins as
disclosed in U.S. Pat. No. 5,395,866; epoxide-vinyl ester resins as
disclosed in U.S. Pat. No. 4,595,734; and combinations thereof. The
relevant portions of U.S. Pat. Nos. 5,395,866 and 4,595,734 are
herein incorporated by reference.
[0191] In embodiments of the invention, the laminating resin system
includes a curable unsaturated polyester resin and optionally a
co-curable unsaturated monomer.
[0192] Curable unsaturated polyester resins are known in the art,
and are generally prepared in a non-limiting sense, by
esterification or transesterification of one or more unsaturated
dicarboxylic acids or reactive derivatives thereof with one or more
aliphatic or cycloaliphatic diols. Saturated dicarboxylic acids,
aromatic dicarboxylic acids, or their reactive derivatives can be
used in conjunction with the unsaturated dicarboxylic acid(s) to
lower the crosslink density. Curable polyester resins are available
commercially, and examples of such are disclosed in, as
non-limiting examples, U.S. Pat. Nos. 3,969,560; 4,172,059;
4,491,642; 4,626,570, and 6,226,958 which are herein incorporated
by reference.
[0193] The curable unsaturated polyester resins can be a high
reactivity polyester resin. Non-limiting examples of suitable high
reactivity polyester resins include, but are not limited to, high
reactivity orthophthalic polyester resins, high reactivity
isophthalic polyester resins, and high reactivity
dicyclopentadiene-modified (DCPD) polyester resins. A particular
non-limiting example of a curable unsaturated high reactivity
polyester resin is a dicyclopentadiene-modified propylene
glycol-maleate polyester resin.
[0194] Co-curable unsaturated monomers are also well known in the
art, and include, as non-limiting examples, the various
alkylacrylates and alkylmethacrylates as well as vinyltoluene
.alpha.-methylstyrene, p-methylstyrene, and styrene. By the term
"co-curing," it is meant that the monomer contains reactive
unsaturation capable of reacting with itself and/or the unsaturated
sites of the curable polyesters under the curing conditions.
Additional co-curable monomers are identified in the
above-referenced patents. A non-limiting example of a co-curable
monomer is styrene.
[0195] Non-limiting examples of suitable laminating resins include
the SILMAR.RTM. and CoREZYN.RTM. products available from
Interplastic Corporation, Saint Paul, Minn., the HI-POINT resins
available from Crompton Corporation, Middlebury, Conn. and the
polyester resins, a non-limiting example being Polyester Resin
30P-105, available from Dura Technologies, Inc., Bloomington,
Calif.
[0196] Suitable fibrous layer fabric that can be used in the
invention includes, but is not limited to, the above-described
fibers in the following forms: plain weave, 14 mils thick cloth;
plain weave, 11 mils thick cloth; plain weave, 10 mils thick cloth;
plain weave, 8 mils thick cloth; plain weave, 5.5 mils thick cloth;
four harness satin weave, 3.5 mils thick cloth; 2/2 twill weave,
9.3 mils thick cloth; modified plain weave, 7.7 mils thick cloth;
eight harness satin weave, 8 mils thick cloth; eight harness satin
weave, 9 mils thick cloth; and layers of combinations of such
fabrics.
[0197] The sports boards utilizing the foam cores or blanks and
methods of construction according to the invention provide boards
that have a rapid "flex memory", the ability of a board to very
quickly "spring" back to its original shape when deformed. Flex
memory can provide, for example, improved acceleration when surfing
and improved turning radius and acceleration when snowboarding.
Thus, flex memory is a desirable attribute that has proved elusive
in prior art sports boards.
[0198] Sports boards constructed according to the invention can be
evaluated using an Emerson 8510 compression tester, (Emerson
Apparatus Company, Inc., Portland, Me.), designed in accordance
with the requirements of ASTM D642 and TAPPI T804 equipment
specifications. In these evaluations, a programmable platen is set
at a rate of 0.5 inches (1.27 cm) per minute using a fixture of the
type used in test protocols for alpine skis, a three point bending
test as described in ASTM Standard 780-93a.
[0199] In this evaluation, the sports board is supported near each
end by a 1.5'' diameter free floating steel rod so as to not apply
any friction to the base of the board as it is being deflected from
the top using a laminated structure that includes a rubber
compliant fixture (19 inches long.times.1.5 inches wide) that
follows the contour of the sports board deck so as to apply an
equal amount of force across its width.
[0200] The amount of deflection that the sports boards according to
the invention can withstand without breaking is greater than what
is observed when compared to prior art sports boards.
[0201] Additionally, where prior art sports boards fail
catastrophically are no longer capable of supporting a load, the
sports boards constructed according the invention are able to
continue to support a load even after failure. In other words,
where prior art sports boards break, sports boards constructed
according the invention bend and are tough enough to maintain some
structural integrity.
[0202] An embodiment of the sports boards according to the
invention is a surfboard as shown in FIGS. 1-4. Surfboard 10 has
foam core elements 12 and 14 as described above separated by
stringer 16 where foam core elements 12 and 14 are located on each
side of stringer 16. Stringer 16 can be made of wood,
carbon/graphite reinforced material, composite material, metal
and/or combinations of such materials.
[0203] During manufacture, stringer 16 can be bowed in a gentle
curve downward for its entire length to form a rocker shape from
nose 18 to tail 20. Stringer 16 can be first formed with an upward
curve from the approximate center to ends and relatively thicker
structure in nose 18 half of stringer 16 relative to tail 20. Tail
20 half of stringer 16 is approximately straight at this step of
the manufacture. Stringer 16 can then be further bowed downward
under pressure in a stringer bending form to produce a gentle curve
downward for approximately one half of its length from tail 20 to
complete the overall rocker shape. Tail 20 end being relatively
thinner bends in the bending form as compared to nose 18 end.
[0204] Thus a tail 20 with a top 22 concave and bottom 23 convex
curved shape longitudinally is created. In addition, stringer 16 is
thereby in a stress or spring condition with energy and tends to
return to the original straight shape. Therefore, any force tending
to bend tail 20 end upward must act against this spring force, thus
providing a strong resistance to bending in an upward direction and
a strong force to return to the original shape. Unique in the
present invention is the added spring force supplied by the foam
core acting to restore the surfboard to its original shape.
[0205] Upper layer covering 24 and under layer covering 26, as
described more fully above are bonded to cover foam core elements
12 and 14 and stringer 16 to form outer layer 28 of surfboard 10.
Outer layer 28 includes two components, a laminating resin with
optionally added fillers and a fabric as described above.
[0206] Wood framed, metal or fiber reinforced epoxy framed fins 30
can be attached on bottom 23 near the tail 20.
[0207] The use of the present foam core elements 12 and 14 provides
a flexible reinforced construction relative to nose 18 and tail 20
in that portion of surfboard 10. This, in combination with stringer
16, provides for flexure in the midsection of surfboard 10 which is
torsional about stringer 16. Further, the density of foam core
elements 12 and 14 can be higher at the nose 18 and tail 20 ends,
and lower in the areas between to further provide flexure in the
midsection of surfboard 10. Stated differently, the more foam core
elements 12 and 14 allow nose 18 and tail 20 portions to tend to
twist about stringer 16 when under pressure, or force of bending
when used in surfing, in the water while nose 18 and tail 20
portions will tend to remain rigid, the greater the resulting
spring back force will be. Optionally, in order to construct
differences in flexure in surfboard 10, upper layer covering 24 and
under layer covering 26 can be varied in stiffness by varying their
respective thickness and/or composition. As a non-limiting example,
nose 18 area can be relatively rigid, tail 20 area can be
relatively rigid and the area in between can be relatively
flexible.
[0208] This design provides for additional surfing or planning
speed due to the spring and torsional action or rapid flex memory
of tail 20 in the water. This feature provides for stability and
ease of turning due to the relative flexibility and shape between
the flexible area and the relatively rigid nose 18 and tail 20 ends
of surfboard 10.
[0209] The embodiments shown in FIG. 4 utilize foam core elements
12 and 14 molded directly into their final shape, or molded nearly
into the final shape and cut in half. As described above, directly
molding the foam core to its final shape allows for a skin to form
on the core elements that is not damaged by the laminating resin.
FIG. 5 shows an embodiment of the invention where the foam core
elements have been molded and then cut to their final shape. In
this embodiment, the outer surfaces of foam core elements 12 and 14
and optionally stringer 16 are coated with sealant coating 32 prior
to upper layer covering 24 and under layer covering 26 being
affixed to foam core elements 12 and 14 and stringer 16.
[0210] An embodiment of the sports boards, according to the
invention, is a surfboard as shown in FIGS. 6-9. Surfboard 110 has
a foam core 112 as described above and a parabolic stringer 116
attached to the outer circumference of foam core 112. Parabolic
stringer 116 can be made of wood, carbon/graphite reinforced
material, composite material or metal.
[0211] In embodiments of the invention, parabolic stringer 116 can
be made in two elements that are constructed such that the ends of
each element accept and/or attach to each other. As a non-limiting
example, at nose 118 and tail 120, the ends of each element of
parabolic stringer 116 can be attached to each other.
[0212] During manufacture, parabolic stringer 116, or its
individual elements, can be bowed in a gentle curve downward for
its entire length to form a rocker shape from nose 118 to tail 120.
Parabolic stringer 116 can be first formed with an upward curve
from the approximate center to ends and relatively thicker
structure in nose 118 half of parabolic stringer 116 relative to
tail 120. Tail 120, half of parabolic stringer 116, or its elements
is approximately straight at this step of the manufacture.
Parabolic stringer 116, or its elements, can then be further bowed
downward under pressure in a stringer bending form to produce a
gentle curve downward for approximately one half of its length from
tail 120, to complete the overall rocker shape. Tail 120 end being
relatively thinner, bends in the bending form as compared to nose
118 end.
[0213] Thus a tail 120 with a top 122 concave and bottom 123 convex
curved shape longitudinally is created. In addition, parabolic
stringer 116 is thereby in a stress or spring condition with energy
and tends to return to the original straight shape. Therefore, any
force tending to bend tail 120 end upward must act against this
spring force, thus providing a strong resistance to bending in an
upward direction and a strong force to return to the original
shape. Unique in the present invention is the added spring force
supplied by foam core 112 acting to restore the surfboard to its
original shape.
[0214] Upper layer covering 124 and under layer covering 126, as
described more fully above, are bonded to cover foam 112 and
parabolic stringer 116 to form outer layer 128 of surfboard 110.
Outer layer 128 includes two components, a laminating resin with
optionally added fillers and a fabric as described above.
[0215] Wood framed, metal or fiber reinforced epoxy framed fins 130
can be attached on bottom 123 near the tail 120.
[0216] In embodiments of the invention, the cross section of
parabolic stringer 116 or its elements can have an inner surface
114 that is concave as shown in FIG. 9 or roughly perpendicular to
top 122 and bottom 123 or straight as shown in FIG. 10.
[0217] The use of the present foam core 112 provides a flexible
reinforced construction relative to nose 118 and tail 120 in that
portion of surfboard 110. This, in combination with parabolic
stringer 116, provides for flexure in the midsection of surfboard
110, which is torsional about parabolic stringer 116. Further, the
density of foam core 112 can be higher at the nose 118 and tail 120
ends and lower in the areas between, to further provide flexure in
the midsection of surfboard 110. Stated differently the more foam
core 112 allows nose 118 and tail 120 portions to tend to twist in
relation to parabolic stringer 116, when under pressure or force of
bending, when used in surfing in the water while nose 118 and tail
120 portions will tend to remain rigid, the greater the resulting
spring back force will be. Optionally, in order to construct
differences in flexure in surfboard 110, upper layer covering 124
and under layer covering 126 can be varied in stiffness by varying
their respective thickness and/or composition. As a non-limiting
example, nose 118 area can be relatively rigid, tail 120 area can
be relatively rigid and the area in between can be relatively
flexible.
[0218] This design provides for additional surfing or planning
speed due to the spring and torsional action or rapid flex memory
of tail 120 in the water. This feature provides for stability and
ease of turning due to the relative flexibility and shape between
the flexible area and the relatively rigid nose 118 and tail 120
ends of surfboard 110. The present foam core and design allow
surfers using surfboards according to the invention to traverse
even the most gnarly waves.
[0219] The embodiments shown in FIG. 9 utilize foam core 112 molded
directly into its final shape, or molded nearly into the final
shape and parabolic stringer 116 either attached thereto or placed
in a mold while foam core 112 is being molded. As described above,
directly molding foam core 112 to its final shape allows for a skin
to form on the foam core that is not damaged by the laminating
resin. FIG. 10 shows an embodiment of the invention where the foam
core has been molded and then cut to its final shape. In this
embodiment, the outer surfaces of foam core 112 and optionally
stringer 116 are coated with sealant coating 132 prior to upper
layer covering 124 and under layer covering 126 being affixed to
foam core 112 and stringer 116.
[0220] In embodiments of the present invention, the above-described
surfboards include an elongate, water resistant or impervious, foam
core containing an interpenetrating network of one or more
polyolefins and one or more polymers of vinyl aromatic monomers
having an upper surface and an under surface; an upper layer
covering at least a portion of the upper surface; and an under
layer covering at least a portion of the under surface, where the
foam core is made of a foam material that has a water absorption
(measured according to ASTM C-272) of less than 2 volume percent at
a density of from 1.5 to 2.5 lb/ft.sup.3.
[0221] The surfboards according to the invention can be provided in
any suitable length, such as big gun (9-foot or longer), longboard
(8-10 feet long) or short board (less than 8 feet) lengths. When
surfs up, the present surfboards provide a rider with the ability
to takeoff and shoot the curl of the most mondo, cruncher or
pounder wave in a quasimoto or other position and walk the board or
perform shred, ripping, cut back, cut out, pull out and/or re-entry
moves with ease. Most importantly, when using the present
surfboards, a dude or dudette can catch a wave, get locked in and
tubed, while screaming "banzai," "cowabunga" or other appropriate
expletives while enjoying a totally excellent gnarlatious ride.
[0222] FIG. 11 shows body board 210 configured to support a rider
in water, has a generally elongate shape defining a longitudinal
axis A, a nose end 212, and a tail end 214. An elongate foam core
216, as described above, provides the main bulk of body board 210,
and foam core 216 is surrounded by an upper layer 218 and an under
layer 220, as well as side layers 222 and 226 all bonded to core
216 as described above.
[0223] Upper layer 218, under layer 220 and side layers 222 and
226, as described more fully above, are bonded to cover foam core
216 and to form outer layer 228 of body board 210. Outer layer 228
includes two components, a laminating resin with optionally added
fillers and a fabric as described above.
[0224] The use of the present foam core 216 provides a flexible
reinforced construction relative to nose 212 and tail 214 in that
portion of body board 210. This in combination with upper layer
218, under layer 220 and side layers 222 and 226 provides for
flexure in the midsection of body board 210 which is torsional
about longitudinal axis A. Further, the density of foam core 216
can be higher at the nose 212 and tail 214 ends and lower in the
areas between to further provide flexure in the midsection of body
board 210. Stated differently the more foam core 216 allows nose
212 and tail 214 portions to tend to twist in relation to
longitudinal axis A, when under pressure, or force of bending when
used in riding waves in the water while nose 212 and tail 214
portions will tend to remain rigid, the greater the resulting
spring back force will be. Optionally, in order to construct
differences in flexure in body board 210, upper layer 218, under
layer 220 and side layers 222 and 226 can be varied in stiffness by
varying their respective thickness and/or composition. As a
non-limiting example, nose 212 area can be relatively rigid, tail
214 area can be relatively rigid and side layers 222 and 226 can be
relatively flexible.
[0225] This design provides for additional planning speed due to
the spring and torsional action or rapid flex memory of tail 214 in
the water. This feature provides for stability and ease of turning.
The present foam core and design allow surfers using surfboards
according to the invention to traverse even the most gnarly
waves.
[0226] The embodiments shown in FIG. 13 utilizes foam core 216
molded directly into its final shape, or molded nearly into the
final shape. As described above, directly molding foam core 216 to
its final shape allows for a skin to form on the foam core that is
not damaged by the laminating resin. FIG. 14 shows an embodiment of
the invention where the foam core has been molded and then cut to
its final shape. In this embodiment, the outer surfaces of foam
core 216 is coated with sealant coating 230 prior to upper layer
218, under layer 220 and side layers 222 and 226 being affixed to
foam core 216.
[0227] Body boards according to the present invention are not
distorted by flex and torsion stress and readily allow for
successful completion of maneuvers by responding to the rider's
steering. External forces do not tend to distort the present body
board, making it easier for a rider to redirect the board. Thus,
adequate and properly placed stiffness is provided in the present
body board. Further, sufficient flex is also provided in the
present body board, allowing the rider to pull up the nose,
distorting it above the plane of the main deck of the body board to
keep the nose and lead corners from dropping under the water's
surface in a dynamic situation where the nose is being forced
downwardly. Thus, flexibility for "power turns" and strength in the
mid and tail sections for speed can readily be provided in the
present body board.
[0228] FIG. 15 shows water ski 310 configured to support a rider in
a standing position while being towed by a motorized watercraft on
water, has a generally elongate shape defining a longitudinal axis
A, a nose end 312, and a tail end 314. An elongate foam core 316,
as described above, provides the main bulk of water ski 310, and
foam core 316 is surrounded by an upper layer 318 and an under
layer 320, as well as side layers 322 and 326 all bonded to core
316 as described above.
[0229] Upper layer 318, under layer 320 and side layers 322 and
326, as described more fully above, are bonded to cover foam core
316 and to form outer layer 328 of water ski 310. Outer layer 328
includes two components, a laminating resin with optionally added
fillers and a fabric as described above.
[0230] Front foot insert 332 and back foot insert 334 can be
attached to top 321 approximately midway between nose end 312 and
tail end 314, or adjusted as desired. When two water skis 310 are
used by a rider, each ski has front foot insert 332 and back foot
insert 334 and the skier can insert a foot into each and ski
conventionally. When slalom skiing is desired, second foot holder
336 can be attached to top 321 between back foot insert 334 and
tail 314. Front foot insert 332, back foot insert 334, and second
foot holder 336 can be constructed of a generally elastomeric
material and attached to top 321 as is known in the art.
[0231] Wood framed or fiber reinforced epoxy framed fins 333 can be
attached on bottom 323 near the tail 120.
[0232] The use of the present foam core 316 provides a flexible
reinforced construction relative to nose 312 and tail 314 in that
portion of water ski 310. This in combination with upper layer 318,
under layer 320 and side layers 322 and 326 provides for flexure in
the midsection of water ski 310 which is torsional about
longitudinal axis A. Further, the density of foam core 316 can be
higher at the nose 312 and tail 314 ends and lower in the areas
between to further provide flexure in the midsection of water ski
310. Stated differently, the more foam core 316 allows nose 312 and
tail 314 portions to tend to twist in relation to longitudinal axis
A when under pressure or force of bending when used in water skiing
while nose 312 and tail 314 portions will tend to remain rigid, the
greater the resulting spring back force will be. Optionally, in
order to construct differences in flexure in water ski 310, upper
layer 318, under layer 320 and side layers 322 and 326 can be
varied in stiffness by varying their respective thickness and/or
composition. As a non-limiting example, nose 312 area can be
relatively rigid, tail 314 area can be relatively rigid and side
layers 322 and 326 can be relatively flexible.
[0233] This design provides for additional planning speed due to
the spring and torsional action or rapid flex memory of tail 314 in
the water. This feature provides for stability and ease of
turning.
[0234] The embodiments shown in FIG. 17 utilizes foam core 316
molded directly into its final shape, or molded nearly into the
final shape. As described above, directly molding foam core 316 to
its final shape allows for a skin to form on the foam core that is
not damaged by the laminating resin. FIG. 18 shows an embodiment of
the invention where the foam core has been molded and then cut to
its final shape. In this embodiment, the outer surfaces of foam
core 316 are coated with sealant coating 330 prior to upper layer
318, under layer 320 and side layers 322 and 326 being affixed to
foam core 316.
[0235] FIGS. 19 and 20 show snowboard assembly 410 that includes
snowboard 412 to which a pair of bindings 414 are mounted to top
side 416 snowboard 412. Bindings 414 can be conventionally mounted
to a center portion snowboard 412.
[0236] FIG. 21 is a cross-section through snowboard 412 of FIGS. 19
and 20. Snowboard 412 includes foam core 418 completely surrounded
by a skin 420 that includes upper layer 422, under layer 424 and
side layers 426 and 428. Skin 420 as described more fully above is
bonded to cover foam core 418 and includes two components, a
laminating resin with optionally added fillers and a fabric as
described above.
[0237] The density of foam core 418 can vary along the length of
snowboard 412. As an example, the density of foam core 412 can be
lower at tip portion 430 and tail portion 432 compared to mid
portion 436.
[0238] The presently constructed snowboard assembly 410 has a mass
moment of inertia, also called swing weight, that is reduced while
maintaining a desired shear strength and compressive strength of
the snowboard. The reduced swing weight permits snowboarders to
more easily perform many maneuvers, especially turns.
[0239] In embodiments of the invention, the shear strength and
crush (compression) strength of foam core 418 between top surface
416 and bottom surface 417 is sufficiently high to provide the
desired swing weight.
[0240] In embodiments of the invention, the density of foam core
418 is no more than about 33% of the density of foam core 418 at
mid portion 436.
[0241] The use of the present foam core 418 provides a flexible
reinforced construction relative to tip portion 430 and tail
portion 432 in that portion of snowboard 412. This, in combination
with upper layer 422, under layer 424 and side layers 426 and 428
can provide for flexure in the midsection of snowboard 412 which
can be torsional about longitudinal axis A. As a non-limiting
example, the more foam core 418 allows tip portion 430 and tail
portion 432 to twist in relation to longitudinal axis A when under
pressure or force of bending when used in snowboarding while tip
portion 430 and tail portion 432 will tend to remain rigid, the
greater the resulting spring back force will be. Optionally, in
order to construct differences in flexure in snowboard 412, upper
layer 422, under layer 424 and side layers 426 and 428 can be
varied in stiffness by varying their respective thickness and/or
composition.
[0242] This design provides for stability and ease of turning.
[0243] The embodiments shown in FIG. 21 utilizes foam core 418
molded directly into its final shape, or molded nearly into the
final shape. As described above, directly molding foam core 418 to
its final shape allows for a skin to form on the foam core that is
not damaged by the laminating resin. FIG. 22 shows an embodiment of
the invention where foam core 418 has been molded and then cut to
its final shape. In this embodiment, the outer surfaces of foam
core 418 is coated with sealant coating 440 prior to upper layer
422, under layer 424 and side layers 426 and 428 being affixed to
foam core 418.
[0244] FIGS. 23 and 24 show snow ski 500 according to the
invention, having a front portion 510, an intermediate portion 508
and a rear portion 512. The ski is provided with a binding that
includes a first portion 514 which is intended to co-act with the
toe piece of a ski-boot and a second portion 516 which is intended
to co-act with the heel of the boot.
[0245] FIG. 25 is a cross-section through snow ski 500 of FIGS. 23
and 24. Snow ski 500 includes foam core 520 completely surrounded
by a skin 522 that includes upper layer 523, under layer 524 and
side layers 526 and 528. Skin 522, as described more fully above,
is bonded to cover foam core 520 and includes two components, a
laminating resin with optionally added fillers and a fabric as
described above.
[0246] The density of foam core 520 can vary along the length of
snow ski 500. As an example, the density of foam core 520 can be
lower at front portion 510 and rear portion 512 compared to
intermediate portion 508.
[0247] The use of the present foam core 520 provides a flexible
reinforced construction relative to front portion 510 and rear
portion 512 in that portion of snow ski 500. This in combination
with upper layer 523, under layer 524 and side layers 526 and 528
can provide for flexure in intermediate portion of snow ski 500. As
a non-limiting example, the more foam core 520 allows front portion
510 and rear portion 512 to deflect when under pressure or force of
bending when used in snow ski 500 while front portion 510 and rear
portion 512 will tend to remain rigid, the greater the resulting
spring back force will be. Optionally, in order to construct
differences in flexure in snow ski 500, upper layer 523, under
layer 524 and side layers 526 and 528 can be varied in stiffness by
varying their respective thickness and/or composition.
[0248] This design provides for stability and ease of turning.
[0249] The embodiments shown in FIG. 25 utilizes foam core 520
molded directly into its final shape, or molded nearly into the
final shape. As described above, directly molding foam core 520 to
its final shape allows for a skin to form on the foam core that is
not damaged by the laminating resin. FIG. 26 shows an embodiment of
the invention where foam core 520 has been molded and then cut to
its final shape. In this embodiment, the outer surfaces of foam
core 520 is coated with sealant coating 540 prior to upper layer
523, under layer 524 and side layers 526 and 528 being affixed to
foam core 520.
[0250] FIGS. 27-30 generally depict a sliding device, or sled
according to the present invention. Sled 600 typically includes
elongate member 602, configured to slide on any sufficiently
slippery surface, such as snow, ice, grass, metal, or water on a
water slide. Often, the surface is covered with snow or ice, and
has a downward slope.
[0251] As illustrated in FIGS. 27-29, elongate member 602 includes
a substantially flat, or planar, body portion 604, and a leading
end portion 606. In use, a rider sits or kneels on body portion
604. Body portion 604 can include one or more handgrip(s) 608,
posterior to leading end portion 606 and anterior to trailing edge
610. Leading end portion 606 has an inward end that is positioned
to connect to or continuous with forward end of body portion 604.
Leading end portion 606 typically extends outward from body portion
604 with an upturned shape, so as to avoid digging into the sliding
surface when sled 600 moves forward.
[0252] Trailing edge 610 can be straight, can have a convex curve,
or can have two or more convex curves, known in the art as bat
tails.
[0253] FIG. 30 is a cross-section through sled 600 at elongate
member 602. Sled 600 includes foam core 620 completely surrounded
by a skin 622 that includes upper layer 623, under layer 624 and
side layers 626 and 628. Skin 622 as described more fully above is
bonded to cover foam core 620 and includes two components, a
laminating resin with optionally added fillers and a fabric as
described above.
[0254] The density of foam core 620 can vary along the length of
sled 600. As an example, the density of foam core 620 can be lower
at leading end portion 606 compared to body portion 604.
[0255] The use of the present foam core 620 provides a flexible
reinforced construction relative to leading end portion 606 and
body portion 604 in that portion of sled 600. This, in combination
with upper layer 623, under layer 624 and side layers 626 and 628
can provide for flexure in sled 600. As a non-limiting example, the
more foam core 620 allows leading end portion 606 to deflect when
under pressure or force of bending when used in sled 600 while body
portion 604 remains rigid, the greater the resulting spring back
force will be. Optionally, in order to construct differences in
flexure in sled 600, upper layer 623, under layer 624 and side
layers 626 and 628 can be varied in stiffness by varying their
respective thickness and/or composition.
[0256] This design provides for stability and ease of turning.
[0257] In FIG. 25 foam core 620 can be molded directly into its
final shape, or molded nearly into the final shape. As described
above, directly molding foam core 620 to its final shape allows for
a skin to form on the foam core that is not damaged by the
laminating resin. In an embodiment of the invention, foam core 620
can be molded and then cut to its final shape. In this embodiment,
the outer surfaces of foam core 620 are coated with sealant coating
640 prior to upper layer 623, under layer 624 and side layers 626
and 628 being affixed to foam core 620.
[0258] One or more hand grip(s) or handles 608 can be affixed to
sled 600 for a rider to grab onto during use. Often, sled 600 has a
pair of handles 608 on opposite sides of sled 600.
[0259] As described above, a blank or foam core element that
includes the above described foamed and molded expandable polymer
matrix is a key component in the sports boards of the present
invention. In various embodiments of the invention, the blank or
foam core element can particularly be used to make surfboards.
[0260] FIGS. 31 and 32 show particular, non-limiting blank or foam
core element embodiments for surfboards according to the invention.
Blank 700 includes lead end 702, tail end 704, rocker portion 706,
and stringer 708 extending from lead end 702 to tail end 704.
[0261] Lead end 702 is generally straight, perpendicular to and
centered about stringer 708. Depending on the intended use and
performance characteristics desired, lead end 702 can have a width
710 of from at least about 2, in some cases at least about 2.5, and
in other cases at least about 3 inches and can be up to about 6, in
some cases up to about 5 and in other cases up to about 4 inches.
Width 710 can be any value or range between any of the values
recited above.
[0262] Tail end 704 is generally straight, perpendicular to and
centered about stringer 708. Depending on the intended use and
performance characteristics desired, tail end 704 can have a width
712 of from at least about 3, in some cases at least about 4, and
in other cases at least about 5 inches and can be up to about 12,
in some cases up to about 10 and in other cases up to about 9
inches. Width 712 can be any value or range between any of the
values recited above.
[0263] Depending on the intended use and performance
characteristics desired, blank 700 can have a length 714 measured
from lead end 710 to tail end 712 of from at least about 4, in some
cases at least about 5, and in other cases at least about 6 feet
and can be up to 10, in some cases up to about 9 and in other cases
up to about 8 feet. Length 714 can be any value or range between
any of the values recited above.
[0264] Rocker portion 706 of blank 700 generally curves upwards
from a bottom surface of blank 700. Rocker portion 706 makes up the
portion of blank 700 near lead end 702 and can be characterized in
terms of what portion of length 714 curves upwardly to form rocker
portion 706. The size of rocker portion 708 will vary depending on
the intended use and performance characteristics desired in
surfboards made from blank 700. Typically, rocker portion 706, can
include at least the lead 10% of length 714, in some cases at least
the lead 15% of length 714, and in other cases at least the lead
20% of length 714 and can be up to the lead 50% of length 714, in
some cases up to the lead 40% of length 714, and in other cases up
to the lead 30% of length 714. Rocker portion 706 of blank 700 can
be any value or range between any of the values recited above.
[0265] Rocker portion 706 of blank 700 can be characterized by the
amount the upward curve departs from the bottom surface of blank
700 (deflection 718). Deflection 718 represents the vertical
distance from the plane of the bottom surface of blank 700 to lead
end 702. The length of deflection 718 in rocker portion 708 will
vary depending on the intended use and performance characteristics
desired in surfboards made from blank 700. Deflection 718 can be at
least about 3 inches, in some cases at least about 4 inches and in
other cases at least about 4.5 inches and can be up to about 10
inches, in some cases at least about 8 inches, and in other cases
at least about 6 inches. The length of deflection 718 can be any
value or range between any of the values recited above.
[0266] Stringer 708 extends from tail end 704 to lead end 702 of
blank 700 and is positioned between first portion 720 and second
portion 722 of blank 700. Stringer 708 generally corresponds to the
shape and curvature of blank 700, and in particular to rocker
portion 706.
[0267] In many aspects of this embodiment, first portion 720 and
second portion 722 are approximately equivalent in size, shape,
weight and dimension. As indicated above, stringer 708 can be made
of wood, carbon/graphite reinforced material, composite material,
metal and/or combinations of such materials. Stringer 708 can be
incorporated into blank 700 by cutting a molded plank of the
expanded polymer matrix into two parts, first portion 720 and
second portion 722, and subsequently using an appropriate adhesive
to attache first portion 720 and second portion 722 to opposing
sides of stringer 708. Alternatively, expansion holes can be placed
through stringer 718 and then be placed in a mold for molding blank
700 as described above. During the molding/bead expansion process,
the expandable polymer matrix prepuff expands and fuses, in
particular, expanding through the expansion holes to provide a one
piece blank of first portion 720, stringer 708 and second portion
722.
[0268] The width and composition of stringer 708 are selected to
provide desirable combinations of stiffness, response and
flexibility. As such, the width of stringer 708, measured as the
distance between first portion 720 and second portion 722, can be
at least about 0.1 inches, in some cases at least about 0.2 inches
and in other cases at least about 0.25 inches and can be up to
about 2 inches, in some cases up to about 1.5 inches and in other
cases up to about 1 inch. The width of stringer 708 can be any
value or range between any of the values recited above.
[0269] FIGS. 33 and 34 show additional particular, non-limiting
blank or foam core element embodiments for surfboards according to
the invention. Blank 750 includes lead end 752, tail end 754,
rocker portion 756, and stringer 758 extending from lead end 752 to
tail end 754.
[0270] Lead end 752 is generally straight, perpendicular to and
centered about stringer 758 and curves into the sides of blank 750.
Depending on the intended use and performance characteristics
desired, lead end 752 can have a width 760 of from at least about
1, in some cases at least about 1.5, and in other cases at least
about 2 inches and can be up to about 5, in some cases up to about
4.5 and in other cases up to about 4 inches. Width 760 can be any
value or range between any of the values recited above.
[0271] Tail end 754 is generally straight, perpendicular to and
centered about stringer 758 and curves into the sides of blank 750.
Depending on the intended use and performance characteristics
desired, tail end 754 can have a width 762 of from at least about
4, in some cases at least about 5, and in other cases at least
about 6 inches and can be up to about 14, in some cases up to about
12 and in other cases up to about 11 inches. Width 762 can be any
value or range between any of the values recited above.
[0272] Depending on the intended use and performance
characteristics desired, blank 750 can have a length 764 measured
from lead end 752 to tail end 754 of from at least about 4, in some
cases at least about 5, and in other cases at least about 6 feet
and can be up to 10, in some cases up to about 9 and in other cases
up to about 8 feet. Length 764 can be any value or range between
any of the values recited above.
[0273] Rocker portion 756 of blank 750 generally curves upwards
from a bottom surface of blank 750. Rocker portion 756 makes up the
portion of blank 750 near lead end 752 and can be characterized in
terms of what portion of length 764 curves upwardly to form rocker
portion 756. The size of rocker portion 758 will vary depending on
the intended use and performance characteristics desired in
surfboards made from blank 750. Typically, rocker portion 756, can
include at least the lead 10% of length 764, in some cases at least
the lead 12.5% of length 764, and in other cases at least the lead
15% of length 764 and can be up to the lead 40% of length 764, in
some cases up to the lead 30% of length 764, and in other cases up
to the lead 25% of length 764. Rocker portion 756 of blank 750 can
be any value or range between any of the values recited above.
[0274] Rocker portion 756 of blank 750 can be characterized by the
amount the upward curve departs from the bottom surface of blank
750 (deflection 768). Deflection 768 represents the vertical
distance from the plane of the bottom surface of blank 750 to lead
end 752. The length of deflection 768 in rocker portion 758 will
vary depending on the intended use and performance characteristics
desired in surfboards made from blank 750. Deflection 768 can be at
least about 2 inches, in some cases at least about 2.5 inches and
in other cases at least about 3 inches and can be up to about 8
inches, in some cases at least about 7 inches, and in other cases
at least about 6 inches. The length of deflection 768 can be any
value or range between any of the values recited above.
[0275] Stringer 758 extends from tail end 754 to lead end 752 of
blank 750 and is positioned between first portion 770 and second
portion 772 of blank 750. Stringer 758 generally corresponds to the
shape and curvature of blank 750, and in particular to rocker
portion 756.
[0276] In many aspects of this embodiment, first portion 770 and
second portion 772 are approximately equivalent in size, shape,
weight and dimension.
[0277] Stringer 758 can be made of materials as described above, be
dimensionally similar to and incorporated into blank 750 using the
methods described in relation to blank 700.
[0278] FIGS. 35 and 36 show further particular, non-limiting blank
or foam core element embodiments for surfboards according to the
invention. Blank 800 includes lead end 802, tail end 804, rocker
portion 806, and stringer 808 extending from lead end 802 to tail
end 804.
[0279] Lead end 802 is generally straight, perpendicular to and
centered about stringer 808 and curves into the sides of blank 800.
Depending on the intended use and performance characteristics
desired, lead end 802 can have a width 810 of from at least about
3, in some cases at least about 4, and in other cases at least
about 5 inches and can be up to about 10, in some cases up to about
9 and in other cases up to about 8 inches. Width 810 can be any
value or range between any of the values recited above.
[0280] Tail end 804 is generally straight, perpendicular to and
centered about stringer 808 and curves into the sides of blank 800.
Depending on the intended use and performance characteristics
desired, tail end 804 can have a width 812 of from at least about
4, in some cases at least about 6, and in other cases at least
about 8 inches and can be up to about 20, in some cases up to about
18 and in other cases up to about 16 inches. Width 812 can be any
value or range between any of the values recited above.
[0281] Depending on the intended use and performance
characteristics desired, blank 800 can have a length 814 measured
from lead end 802 to tail end 804 of from at least about 4, in some
cases at least about 5, and in other cases at least about 6 feet
and can be up to 10, in some cases up to about 9 and in other cases
up to about 8 feet. Length 814 can be any value or range between
any of the values recited above.
[0282] Rocker portion 806 of blank 800 generally curves upwards
from a bottom surface of blank 800. Rocker portion 806 makes up the
portion of blank 800 near lead end 802 and can be characterized in
terms of what portion of length 814 curves upwardly to form rocker
portion 806. The size of rocker portion 808 will vary depending on
the intended use and performance characteristics desired in
surfboards made from blank 800. Typically, rocker portion 806, can
include at least the lead 10% of length 814, in some cases at least
the lead 12.5% of length 814, and in other cases at least the lead
15% of length 814 and can be up to the lead 40% of length 814, in
some cases up to the lead 30% of length 814, and in other cases up
to the lead 25% of length 814. Rocker portion 806 of blank 800 can
be any value or range between any of the values recited above.
[0283] Rocker portion 806 of blank 800 can be characterized by the
amount the upward curve departs from the bottom surface of blank
800 (deflection 818). Deflection 818 represents the vertical
distance from the plane of the bottom surface of blank 800 to lead
end 802. The length of deflection 818 in rocker portion 808 will
vary depending on the intended use and performance characteristics
desired in surfboards made from blank 800. Deflection 818 can be at
least about 2 inches, in some cases at least about 2.5 inches and
in other cases at least about 3 inches and can be up to about 9
inches, in some cases at least about 8 inches, and in other cases
at least about 7 inches. The length of deflection 818 can be any
value or range between any of the values recited above.
[0284] Stringer 808 extends from tail end 804 to lead end 802 of
blank 800 and is positioned between first portion 820 and second
portion 822 of blank 800. Stringer 808 generally corresponds to the
shape and curvature of blank 800, and in particular to rocker
portion 806.
[0285] In many aspects of this embodiment, first portion 820 and
second portion 822 are approximately equivalent in size, shape,
weight and dimension.
[0286] Stringer 808 can be made of materials as described above, be
dimensionally similar to and incorporated into blank 800 using the
methods described in relation to blank 700.
[0287] In embodiments of the invention, surfboards made according
to the invention using the cores or blanks described in FIGS. 31-36
can be deflected using the Emerson 8510 compression tester
apparatus as described 0.75 inches (1.9 cm), in some cases 0.79
inches (2 cm) and in particular instances 0.83 inches (2.1 cm)
without demonstrating a deflection in the stress-strain curve.
Additionally, the present surfboards do not fail when deflected
0.87 inches (2.2 cm), in some cases 0.91 inches (2.3 cm) and in
particular instances 0.94 inches (2.4 cm). After such deflections,
the present surfboards are able to return to their original shape.
The particular properties of a particular board will depend on the
composition of the blank or core and laminating resin used to glass
the surfboard.
[0288] Further, even after failure of the present surfboards using
the Emerson 8510 compression tester apparatus as described above,
the present surfboards are able to support a load of at least 100
pounds (45.4 kg), in some cases at least 150 pounds (68 kg) and in
other cases at least 200 pounds (91 kg). The particular properties
of a particular board will depend on the composition of the blank
or core and laminating resin used to glass the surfboard.
[0289] Because the sports boards of the present invention are made
from the above-described expanded polymer matrix, they are
generally lighter in weight than conventional sports boards, but
can be handled in the same way because of the physical
characteristics of the foam core and sports boards as described
above. As such, the present sports boards are ideally suited for
use in various sporting activities.
[0290] Various embodiments and structures have been described
herein, which are not meant to be limiting to one application.
Various designs and structures of one type of sports board can be
incorporated into other types of sports boards to obtain desired
characteristics as those skilled in the art will readily
appreciate.
[0291] The present invention will further be described by reference
to the following examples. The following examples are merely
illustrative of the invention and are not intended to be
limiting.
Example 1
[0292] This example demonstrates the superior flexibility of
surfboards made according to the invention.
[0293] Test Apparatus
[0294] Testing was conducted on an Emerson 8510 compression tester,
(Emerson Apparatus Company, Inc., Portland, Me.), designed in
accordance with the requirements of ASTM D642 and TAPPI T804
equipment specifications. The programmable platen was set at a rate
of 0.5 inches (1.27 cm) per minute. The fixture used was a modified
design of the general test protocol for alpine skis, a three point
bending test to ASTM Standard 780-93a.
[0295] Each surfboard was placed on the fixture, which was
installed under the Emerson apparatus aligned to the same center
point. The base of each surfboard was supported by a 1.5'' diameter
free floating steel rod so as to not apply any friction to the base
of the board as it was being deflected from the top. The spacing
between the bottom rails is 28 inches and the selection of the
spacing was determined through findings of the major compression
points from the tail and lead end typically found while
surfing.
[0296] The upper force fixture placed a downward force on the
center of the surfboard as measured 38 inches form the lead end of
the surfboard. The laminated structure included a rubber compliant
fixture (19 inches long.times.1.5 inches wide) that followed the
contour of the surfboard deck so as to apply an equal amount of
force across the width of the surfboard.
[0297] Sample Description
[0298] The sample surfboards were similar to those shown in FIGS.
31 and 32, approximately 70 inches (178 cm) long. The blanks for
each sample were molded, and cut in half lengthwise and a wooden
stringer attached to each half with an adhesive. The blanks were
glassed using a polyester laminate. All ingredients and
construction were identical except for the foam material for the
blanks, which were as follows: [0299] Sample 1: 2.5 lb/ft.sup.3 (40
kg/m.sup.3) density polyurethane [0300] Sample 2: 2.5 lb/ft.sup.3
(40 kg/m.sup.3) density expanded ARCEL.RTM. 730 resin (NOVA
Chemicals Inc., Pittsburgh, Pa.)
[0301] Each surfboard was placed on the test apparatus and the
platen was lowered until a break in the stress-strain curve
indicated a failure. Sample 1 indicated a failure at 0.71 inches
(1.8 cm) of deflection and sample 2 at 0.79 inches (2.0 cm) of
deflection.
[0302] The performance of the foam crushing after the structural
failure of each surfboard was evident in the formation of a
downward trend in the stress-strain curve. The compressive set
observed in samples 1 was much lower than that of sample 2, the
foam in which appeared to store a degree of latent energy during
compression.
[0303] The data demonstrate the superior flexibility of the
surfboard made according to the invention.
Example 2
[0304] This example demonstrates the superior flexibility of
surfboards made according to the invention. The test apparatus
described in Example 1 was also used in this Example.
[0305] Sample Description
[0306] The sample surfboards were similar to those shown in FIGS.
31 and 32, approximately 70 inches (178 cm) long. The blanks for
each sample were molded, and cut in half lengthwise and a wooden
stringer attached to each half with an adhesive. The blanks were
glassed using an epoxy laminate. All ingredients and construction
were identical except for the foam material for the blanks, which
were as follows: [0307] Sample 3: 2.5 lb/ft.sup.3 (40 kg/m.sup.3)
density expanded polystyrene [0308] Sample 4: 2.5 lb/ft.sup.3 (40
kg/m.sup.3) density expanded ARCEL.RTM. 730 resin
[0309] Each surfboard was placed on the test apparatus and the
platen was lowered until a break in the stress-strain curve
indicated a failure. Sample 3 indicated a failure at 0.71 inches
(1.8 cm) and sample 4 at 0.85 inches (2.2 cm) of deflection.
[0310] The performance of the foam crushing after the structural
failure of each surfboard was evident in the formation of a
downward trend in the stress-strain curve. The compressive set
observed in samples 3 was much lower than that of sample 4, the
foam in which appeared to store a degree of latent energy during
compression.
[0311] The data demonstrate the superior flexibility of the
surfboard made according to the invention.
Example 3
[0312] This example demonstrates the effect of laminate on the
flexibility of surfboards made according to the invention. The test
apparatus described in Example 1 was also used in this Example.
[0313] The sample surfboards were similar to those shown in FIGS.
31 and 32, approximately 70 inches (178 cm) long. The blanks for
each sample were molded, and cut in half lengthwise and a wooden
stringer attached to each half with an adhesive. The foam used for
the blanks was 2.5 lb/ft.sup.3 (40 kg/m.sup.3) density expanded
ARCEL.RTM. 730 resin. All ingredients and construction were
identical except for the laminate resin used to glass the blanks,
which were as follows: [0314] Sample 5: blank glassed using an
epoxy laminate [0315] Sample 6: blank glassed using a polyester
laminate
[0316] Each surfboard was placed on the test apparatus and the
platen was lowered at a rate of 0.5 inches (1.27 cm) per minute to
a deflection of 1 inch (2.54 cm). The deflection and load where a
break in the stress-strain curve was noted as a deflection point.
The deflection point for sample 5 was 0.85 inches (2.2 cm) at a
load of 886 lb. (402 kg) and for sample 6 was 0.79 inches (2.0 cm)
at a load of 728 lb. (330 kg).
[0317] The test above was repeated on the same boards, except the
platen was lowered at a rate of 0.5 inches (1.27 cm) per minute to
a deflection of 1.5 inches (3.8 cm). The deflection and load where
a break in the stress-strain curve was again noted as a deflection
point. The deflection point for sample 5 was 0.99 inches (2.5 cm)
at a load of 687 lb. (312 kg) and for sample 6 was 0.95 inches (2.4
cm) at a load of 525 lb. (238 kg). Although both surfboards
exhibited a deflection point, complete failure was not observed and
the foam blank of each surfboard continued to support a load at the
1.5 inches (3.8 cm) deflection, 510 lb. (231 kg) for sample 5 and
490 lb. (222 kg) for sample 6.
[0318] A comparable test with the polyurethane surfboard of sample
1 demonstrated complete failure and no load support at 1.2 inches
(3 cm) deflection. A comparable test with the expanded polystyrene
surfboard of sample 3 demonstrated complete failure and no load
support at 1.35 inches (3.4 cm) deflection.
[0319] A 2 inch (5 cm) diameter plug with a rounded top was
engineered and fastened to a rigid base to support the plug. This
fixture was attached with clamps to the upper moving platen of the
Emerson compression tester. The face plate of the test fixture was
driven downward at a rate of 0.5 inches (1.27 cm) per minute. The
base of each surfboard was affixed to a solid steel table placed
under the moving platen.
[0320] The outer skin of the sample 4 (epoxy laminate) provided a
more durable shell demonstrating a peak load at 430 pounds (190 kg)
with a peak deflection at 0.0456 inches (0.12 cm). Sample 5
demonstrated a peak load of 245 pounds (111 kg) at a crack
deflection of 0.315 inches (0.8 cm).
[0321] The data demonstrate the toughness and durability properties
of surfboards made according to the present invention and also
highlight the improved safety features of such a board, as a safe
degree of integrity is maintained even under conditions where prior
art surfboards fail catastrophically.
[0322] The present invention has been described with reference to
specific details of particular embodiments thereof. It is not
intended that such details be regarded as limitations upon the
scope of the invention except insofar as and to the extent that
they are included in the accompanying claims.
* * * * *