U.S. patent application number 10/135993 was filed with the patent office on 2002-12-12 for synthetic construction matting.
Invention is credited to Holden, Ernest E. JR., Parker, Robert S., Phillips, Mark L..
Application Number | 20020188074 10/135993 |
Document ID | / |
Family ID | 24520810 |
Filed Date | 2002-12-12 |
United States Patent
Application |
20020188074 |
Kind Code |
A1 |
Parker, Robert S. ; et
al. |
December 12, 2002 |
Synthetic construction matting
Abstract
A method of producing extruded synthetic lumber for use in
construction matting comprising the steps of first, providing a
blend of ground synthetic particles, the blend selected from the
group comprising primarily ground high density polyethylene
particles and ground polyethylene terephthalate particles in an
amount not more than 99.0 percent by weight and a composition of
ground styrene-butadiene rubber comprised primarily of tire
buffings in an amount from 1.0 percent to about 3.5 percent by
weight. The blend is mixed, heated and extruded into dimensional
lumber and then cooled. The resulting lumber has a low retained
memory and reduced electrosstatic potential.
Inventors: |
Parker, Robert S.;
(Lafayette, LA) ; Holden, Ernest E. JR.;
(Lafayette, LA) ; Phillips, Mark L.; (Lafayette,
LA) |
Correspondence
Address: |
William W. Stagg
Attorney-at-Law
Durio, McGoffin & Stagg
P.O. Box 51308
Lafayette
LA
70505
US
|
Family ID: |
24520810 |
Appl. No.: |
10/135993 |
Filed: |
April 29, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10135993 |
Apr 29, 2002 |
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09628909 |
Jul 31, 2000 |
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6380309 |
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Current U.S.
Class: |
525/166 |
Current CPC
Class: |
E01C 9/086 20130101;
B29C 48/07 20190201 |
Class at
Publication: |
525/166 |
International
Class: |
C08L 067/02 |
Claims
1. A method of producing a synthetic structural material for use in
constructing mats for temporary roads and access areas, which
comprises the step of producing an extruded synthetic structural
member comprising primarily: (i) synthetic material selected from
the group consisting of high density polyethylene and polyethylene
terephthalate in an amount not more than 99.0 percent by weight;
and (ii) a composition of styrene-butadiene rubber comprised
primarily of tire buffings in the range from 1.0 percent to about
3.5 percent by weight.
2. A method of producing a synthetic structural material for use in
constructing mats for temporary roads and access areas as recited
in claim 1 wherein, said high density polyethylene, said
polyethylene terephthalate and said composition of
styrene-butadiene rubber comprised primarily of tire buffings, when
combined, have a water content of less than 0.5 percent by
weight.
3. A method of producing a synthetic structural material for use in
constructing mats for temporary roads and access areas as recited
in claim 2 wherein, said range of said composition of
styrene-butadiene rubber comprised primarily of tire buffings is
from about 2.0 percent to about 3.5 percent by weight.
4. A method of producing a synthetic structural material for use in
constructing mats for temporary roads and access areas, which
comprises the step of producing an extruded synthetic structural
member comprising: (i) ground high density polyethylene in an
amount greater than 90.0 percent by weight; and (ii) a composition
of ground styrene-butadiene rubber comprised primarily of tire
buffings in an amount from about 1.0 percent to about 3.5 percent
by weight.
5. The method of producing a synthetic structural material for use
in constructing mats for temporary roads and access areas as
recited in claim 4 wherein, said high density polyethylene and said
composition of styrene-butadiene rubber comprised primarily of tire
buffings, when combined, have a water content of less than 0.5
percent by weight.
6. The method of producing a synthetic structural material for use
in constructing mats for temporary roads and access areas which
comprises the step of producing an extruded synthetic structural
member comprising: (i) ground high density polyethylene in an
amount not more than 75.0 percent by weight; (ii) a composition of
ground styrene-butadiene rubber comprised primarily of tire
buffings in the range from about 2.0 percent to about 3.5 percent
by weight; and (iii) ground polyethylene terephthalate in an amount
not more than 40.0 percent by weight.
7. A method of producing extruded synthetic lumber comprising the
steps of: (i) first, providing a blend of ground synthetic
particles, said blend comprising primarily ground synthetic
particles selected from the group consisting of ground high density
polyethylene particles and ground polyethylene terephthalate
particles in an amount not more than 99.0 percent by weight of said
blend and a composition of ground styrene-butadiene rubber
comprised primarily of tire buffings in an amount from 1.0 percent
to about 3.5 percent by weight of said blend; (ii) next, mixing
said blend; (iii) then, heating said blend; and (iv) extruding said
blend into dimensional lumber; and (v) then cooling said extruded
dimensional lumber.
8. The method of producing extruded synthetic lumber as recited in
claim 7 wherein, said range of said ground styrene-butadiene rubber
comprised primarily of tire buffings is from 2.0 percent to 3.5
percent by weight.
9. The method as recited in claim 8 wherein said particles of said
blend of ground synthetic particles are sized to pass a 2.5 cm
sieve.
10. The method of producing extruded synthetic lumber as recited in
claim 9 wherein, said blend of ground synthetic particles has a
water content of less than 0.5 percent by weight.
11. A method of producing synthetic mats for temporary roads and
access areas, which comprises the step of producing an extruded
synthetic structural member from a blend of ground synthetic
material, said blend of ground synthetic material comprising: (i) a
composition consisting primarily of ground high density
polyethylene in an amount greater than 90.0 percent by weight; (ii)
a composition consisting primarily of ground styrene-butadiene
rubber comprised primarily of tire buffings in an amount from 1.0
percent to 3.5 percent by weight; and (iii) a composition
consisting primarily of ground polyethylene terephthalate as a
filler.
12. The method as recited in claim 11 wherein, in said blend of
ground synthetic material, said composition of ground high density
polyethylene and said composition of ground polyethylene
terephthalate, together, is no more than 99.0 percent by weight of
said blend and said composition consisting primarily of ground
styrene-butadiene rubber comprised primarily of tire buffings is in
the range from about 1.0 percent to about 3.5 percent by weight of
said blend.
13. The method as recited in claim 12 wherein said step of
producing said extruded synthetic structural member from said blend
of ground synthetic material includes the steps of: (i) mixing said
blend; (ii) then, heating said blend; (iv) then, extruding said
blend into dimensional lumber; and (v) then cooling said extruded
dimensional lumber.
14. The method as recited in claim 13 wherein blend of ground
synthetic material is sized to pass a 2.5 cm sieve.
15. The method as recited in claim 14 wherein said blend of ground
synthetic material has a water content of less than 0.5 percent by
weight.
Description
[0001] This is a continuation of U.S. patent application Ser. No.
09/628,909 filed Jul. 31, 2000.
FIELD OF INVENTION:
[0002] The present invention relates to materials used in
fabricating temporary access mats and matting systems and, more
particularly, presents a unique formulation of synethetic materials
for use in matting for temporary roads and work surface areas.
BACKGROUND OF THE INVENTION
[0003] Wooden mats have traditionally been utilized in the oil and
gas and construction industries to form temporary roads and access
areas at drill site locations and other construction sites. Such
wooden mats provide a temporary foundation for construction
vehicles and for construction equipment such as cranes and
draglines. The temporary roads and access areas are formed by
laying individual wooden mats in a desired pattern. This pattern of
individual mats provides access over and around work areas with
poor soil conditions that would otherwise be inaccessible to heavy
trucks and construction equipment. When the drilling or
construction is completed these mats can be removed for utilization
elsewhere.
[0004] Wooden mats are also used in many marine applications. Such
applications, include the use of wooden mats or matting to cover
the decks of ships, barges and other marine vessels. Wooden matting
is also used in the construction of docks, harbors and walkways
around such marine structures.
[0005] The use of wooden mats present certain disadvantages. The
mats are typically made of layers of wood timbers spiked or bolted
together. The timbers forming the mats are subject of splitting,
warping, breakage and disposal in compliance with state and federal
regulations. Mats having split, broken or warped surfaces can
produce imperfections in the matted surfaces that impede the access
of the heavy equipment or cause damage to the equipment. The wooden
mats used to form the matted surfaces are also expensive, require
substantial maintenance, and increase the demand on forests that
produce timber and timber products. Wooden mats are also heavy and
can be difficult to move, place and store.
[0006] Applicants' herein propose formulas for blending a
combination of synthetic structural materials to produce structural
members for use in the construction of mats and matting systems.
U.S. Pat. No. 5,653,551 to Seaux suggests a mat system having
individual mats comprised of composite materials. Seaux proposes a
combination of virgin resins, plastics, re-claimed polyolefins and
vulcanized rubber in further combination with strengthening agents
such as fiberglass, steel, graphite, nylon or combinations of the
materials. However, the Seaux patent makes no suggestion as to a
preferred proportion or combination of such composite materials to
be used in forming the mat.
[0007] There are many problems associated with the use of structual
members comprising synthetic materials in the formation of
construction matting. Construction matting is subjected to heavy
vehicle loads and, more often than not, is used in areas where poor
soil conditions are prevelent. Such mats must be sufficiently rigid
to distribute the vehicle loading over the matted area and yet be
elastic enough to retain the shape of the matting.
[0008] The loads encountered at a typical construction site often
produce pronounced deflections in mats constructed of structural
members composed of synthetic materials. Such mats, as a product of
such loads and deflection, often retain too much "memory" which
results in the creation of a permanent deformation in the matting.
This retained memory or deformation reduces the mats ability to
distribute the traffic loads to the soil surface and such retained
deformation may require frequent replacement of the mats.
[0009] The use of synthetic materials in structural materials for
matting may also enhance the electrostatic properties of the
matting and thus increase the incidence of sparking with a
resulting increased risk of explosion. Mats constructed from
structural members made with certain synthetic materials may also
present problems due to separation of component parts of the mat
when conventional fasteners such as screws, spikes or bolts are
used to secure the mat components together. The Seaux patent does
not present a formulation of synthetic materials to address these
problems.
[0010] Others have suggested the use of synthentic materials,
particularly waste plastics and elastomers, for making construction
materials. Examples of such are described in U.S. Pat. No.
5,030,662 to Banerjie and U.S. Pat. No. 5,759,680 to Brooks. Both
the Banerjie and Brooks patents primarily feature the use of
various polyethylenes as the bulk of the matrix forming structural
member. The Banerjie patent teaches the use of polyolefins in
conjunction with compatibilizers, impact modifiers and reinforcing
agents in the matrix forming the structural member. The Brooks
patent teaches the use of polyolefins in conjunction with
cellulosic fibers in the matrix of the structural member. Neither
patent presents a formulation of synthetic materials to address the
aforementioned problems presented when such synthetic materials are
used to produce structural members for use in construction
matting.
[0011] Scrap rubber has also been suggested for use as a component
in the formulation of synthetic building materials. In U.S. Pat.
No. 5,439,735 to Jamison rubber is suggested as a component
material for particle board products, because of its resistance to
decay, water, rot, insects, and its thermal and acoustic
properties.
[0012] In U.S. Pat. No. 4,244,841 to Frankland a method of using
grindings of scrap tire rubber is proposed for producing structures
such as paving stones, floor coverings, resilient bumpers for
highway guardrails, and railroad tie pads. In U.S. Pat. No.
4,851,500 to Lalwani teaches a process for blending scrap as a
component of the material used in making roofing, walkway pads, and
tiles. U.S. Pat. No. 5,886,078 to Sullivan et al. discloses the use
of polymeric composites comprising thermoplastic polyolefins, a
rubbery polymeric component such as styrene-butadine rubber in
amounts greater than 4.0 percent by weight and reinforcing filler
as a replacement for wood for use as railroad ties.
[0013] None of the aforementioned disclose the unique combination
of rubber and synthetic components having the structural and
physical properties of flexibility, the resiliencey and reduced
retained load memory and the low electrostatic characteristics that
were found by applicants to be suitable for temporary matting to be
used in the oil and gas and in the construction industries.
SUMMARY OF INVENTION
[0014] The present invention presents a unique formulation for
synthetic structural material blended and extruded primarily from
high density polyethylene (HDPE), polyethylene terephthalate (PET),
and styrene.about.butadiene rubber (SBR). The unique formulations
presented herein, when appropriately specified and blended, offer
structure building materials that are long lived, flexible, without
retaining load "memory" and that are resistant to ultraviolet
light, ozone, weather, insect and microbial degradation and
electrostatic buildup. A further desired characteristic of the
structural materials blended and extruded as described and claimed
herein is that such materials have a low electrostatic potential.
This reduces the incidence of sparks associated with electrostatic
potential and as a result reduces the chance of associated
explosion and fire.
[0015] The formulations described and claimed herein also impart
qualities to the structural members so produced that facilitate
their use as construction material as they accommodate the use of
traditional tools and traditional fasteners such as spikes, nails,
screws and bolts. In addition, the formulations described and
claimed result in producing structural materials having excellent
compressive, shear and tensile strength, and high moduli of
elasticity and rupture as determined by ASTM standard test
methods.
[0016] While the precise amounts of each of the components above
may vary according to the desired properties of the ultimate
matrix, and while particle sizes and particle preparation may
affect the characteristics of the final product material, it is
thought that the formulations instructed herein, within the general
range, and percentages of materials described, will achieve the
specific listed and desired material characteristics for use as
construction matting.
[0017] The primary components of Applicants' formulations, high
density polyethylene (HDPE), polyethylene terephthalate (PET), and
styrene.about.butadiene rubber (SBR), can be obtained from virgin
materials manufacturers and/or distributors. In addition to
component availability through new material suppliers, these
components are widely available through recovered materials
markets. The reutilization of these polymers is widely recognized
to be of paramount importance to conserve energy, landfill space,
and other resources given that such materials represent a
considerable percentage of the overall waste stream and volumes are
generally increasing every year. Although many modern composite
materials that specify SBR prefer to utilize "devulcanized" feed
stocks owing to their much improved cross-linking/bonding
abilities, for most of the applications addressed herein, simple,
physical preparations and detail to particle size results in
products achieving the desired characteristics.
[0018] Ground or granulated rubber from vehicle tires known as
"tire buffings" and particulary tire buffings made from truck tire
treads provide an adequate and desirable source of SBR for use in
Applicants' formulations. In addition to SBR, tire buffings may
include natural rubber, cis-polybutadiene rubber and
cis-polyisoprene rubbers. Tire buffings also typically include
accelerators such as zinc oxide, lead monoxide, magnesium oxide,
stearic acid, oleic acid and pine tar; antioxidants including
paraminophenol, phenyl-alphanaphthylamine, phenylbetanaphthylamine;
carbon disulfide as an anti-ozone additive; sulfur as a
vulcanization agent for the natural rubber components; and carbon
black as a reinforing material that imparts high tensile strength
to the rubber combination to increase its resistance to abrasion
and cutting and reduce electrostatic potential. When tire buffings
are used as source of the SBR composition set forth in Applicants'
formulations, the tire buffings serve to impede the build up of
static electricity in structural members produced with the
formulations and the incidence of sparks associated with the
structural members so produced.
DESCRIPTION OF PREFERRED EMBODIMENTS
FORMULA I
[0019] It is thought that structural members extruded to a desired
size from the formulations consisting primarily of the following
component materials, in the following proportions, ground to a
desired particle size and blended together by weight in the absence
of water (i.e., <0.5% by weight) would be suitable for use in
construction matting and would have the desired characteristics of
reduced electrostatic potential and reduced load memory:
1 COMPONENT RANGE OF PREFERRED PERCENTAGE FORMULA I HDPE At least
90.0 percent by weight An SBR composition In the range of 1.0-3.5
percent by weight comprised primarily of tire buffings FORMULA II
PET At least 90.0 percent by weight An SBR composition In the range
of 1.0-3.5 percent by weight comprised primarily of tire
buffings
[0020] PET and HDPE may be used as a filler in Formula I or Formula
II, respectively. The components in Formula I and Formula II should
be mixed in the specified range of percentages, then heated and
extruded into dimensional lumber and then cooled in a water bath.
While a precise grinding or gradation of component particles
comprising the blend of Formula I and Formula II is not thought to
be required, the particle size so blended would be thought to pass
a 2.5 cm sieve.
[0021] It is thought that the materials as listed and described in
Formula I and Formula II when blended as described would produced a
synthetic lumber building material with the structural
characteristics shown in Table I when tested as indicated:
2TABLE I PROPERTY TEST METHOD RANGE OF VALUES Modulus of Elasticity
ASTM D790 140,000 psi-183,000 psi Tensile Strength ASTM D198 1,453
psi-1,587 psi
FORMULA III
[0022] As an alternative embodiment, it is thought that structural
members extruded to a desired size from a formulation consisting
primarily of the following component materials, in the following
proportions, ground to a desired particle size and blended together
by weight in the absence of water (i.e., <0.5% by weight), would
be suitable for use in construction matting and have the desired
characteristics of reduced electrostatic potential and reduced load
memory:
3 COMPONENT RANGE OF PREFERRED PERCENTAGE HDPE in an amount not
more than 75.0 percent by weight An SBR in the range of 1.0-3.5
percent by weight composition comprised primarily of tire buffings
PET in an amount not more than 40.0 percent by weight
[0023] It is thought that the components in Formula III when mixed
and blended in the specified range of percentages and then heated
and extruded into dimensional lumber and then cooled in a water
bath would also produce a synthetic lumber with a desired
electrostatic potential and with the a desired structural
flexibility and load memory.
[0024] One of significant characteristic of the synthetic lumber
boards extruded from the blends in accordance with the above
formulas is that it is thought that the electrostatic potential of
the synthetic lumber will be lowered by increasing the amount of
tire buffings. However, the desire to achieve the characteristic of
a lower electrostatic potential for the synthetic lumber must be
balanced with the resulting increase in flexibility and,
consequently, the increase in the retained "memory" from a
deflection or deformation of the synthetic lumber under loading
imparted when the amount of tire buffings utilized in the blend is
increased.
[0025] It is thought that synthetic structural members produced
from the materials specified and blended as described herein would
produce construction matting that, when exposed to the environment,
would long out live construction matting produced with popular
alternatives such as matting made from wood or from "single
component" recovered plastics. In addition, and as a consequence of
the lowered electrostatic potential of the formulations, matting
made from the composite materials outlined herein could be safely
utilized in environments where electrostatic arching must be
avoided (i.e., hazardous materials storage areas, oil and gas
locations and other potentially explosive/flammable areas).
[0026] It is thought that the formulations for synthetic structural
material and method of the present invention and many of its
attendant advantages will be understood from the foregoing
descriptions. It is also thought that various changes or
modifications may be made to the methods and formulations presented
without departing from the spirit and scope of the present
invention.
* * * * *