U.S. patent application number 10/554886 was filed with the patent office on 2007-02-01 for packaging for bitumen.
Invention is credited to Jean-Luc Albert Vital Marchal.
Application Number | 20070027235 10/554886 |
Document ID | / |
Family ID | 33414919 |
Filed Date | 2007-02-01 |
United States Patent
Application |
20070027235 |
Kind Code |
A1 |
Marchal; Jean-Luc Albert
Vital |
February 1, 2007 |
Packaging for bitumen
Abstract
A consumable bitumen packaging compound including at least one
packaging material/s, such as polymers, plastics and extenders and
the like, used in combination with the bituminous material and a
metal, either pure in powder form or in the form of salt or oxide,
that is physically and/or chemically combined with the polymer
material, so that the density of the packaging material is adjusted
to prevent the material from floating to the surface of the molten
material after melting. The components of the packaging are
preferably selected such that they are compatible with the bitumen.
After transport and storage, the packaging material can therefore
be directly incorporated into the bitumen product for final use,
such that the formation of a polymer skin accumulating at the
surface of the molten material is largely avoided.
Inventors: |
Marchal; Jean-Luc Albert Vital;
(Singapore, SG) |
Correspondence
Address: |
Law Offices of Albert Wai Kit Chan
World Plaza Suite 604
141 07 20th Avenue
Whitestone
NY
11357
US
|
Family ID: |
33414919 |
Appl. No.: |
10/554886 |
Filed: |
April 30, 2003 |
PCT Filed: |
April 30, 2003 |
PCT NO: |
PCT/SG03/00101 |
371 Date: |
August 14, 2006 |
Current U.S.
Class: |
524/59 ;
524/431 |
Current CPC
Class: |
C08L 29/04 20130101;
C08L 33/06 20130101; C08L 23/0853 20130101; C08L 23/02 20130101;
C08L 31/06 20130101; Y10T 428/1397 20150115; C08L 31/04 20130101;
C08L 35/06 20130101; Y10T 428/1352 20150115; C08L 23/02 20130101;
C08L 53/02 20130101; C08L 35/06 20130101; C08L 29/04 20130101; Y10T
428/1386 20150115; C08L 33/06 20130101; C08L 23/0853 20130101; C08L
95/00 20130101; C08L 95/00 20130101; C08L 53/02 20130101; C08L
95/00 20130101; C08L 95/00 20130101; C08L 95/00 20130101; C08L
95/00 20130101; C08L 95/00 20130101; C08L 95/00 20130101; C08K 3/10
20130101; C08L 95/00 20130101; C08L 31/06 20130101; C08L 31/04
20130101 |
Class at
Publication: |
524/059 ;
524/431 |
International
Class: |
C08L 95/00 20060101
C08L095/00 |
Claims
1. A consumable container for use in transport and/or
melt-processing operations, or a film suitable for use in
packaging, said container or film composed of a composition
comprising: i) 60.1% to 99.9% by weight of a moldable material
composed of a plastic or polymer material wherein 0.1% to 39.9% of
said 60.1% to 99.9% is bituminous material; and ii) 0.1% to 39.9%
by weight of a dense metallic material.
2. A container or film according to claim 1, wherein the plastic or
polymer material is selected from polyethylene, polypropylene,
polystyrene, styrene-butadiene-styrene, styrene-butadiene,
styrene-indene-styrene, copolymers of acrylates and methacrylates,
ethylene-vinyl-acetate, atactic polypropylene, mineral or natural
or synthetic fibers, and mixtures thereof.
3. A container or film according to claim 1 or 2, wherein the
plastic or polymer material is an ethylene-vinyl-acetate
copolymer.
4. A container or film according to claim 1, 2 or 3, wherein the
bituminous material is selected from bitumen, oxidized bitumen,
semi-blown bitumen, natural occurring bitumen, refinery heavy
residues, heavy fuel-oil, extracts, petroleum-tar, coal-tar,
aromatic extracts, synthetic resins, natural resins and mixtures
thereof.
5. A container or film according to any one of the preceding claims
wherein the metallic material is a source of metal ions derived
from at least one metal or the salts and oxides thereof and/or a
metal complex.
6. A container or film according to any one of the preceding
claims, wherein the metallic material is in a powder, pellet or
granular form.
7. A container or film according to claim 5 or 6, wherein the
metallic material is or comprises iron, calcium, an iron oxide,
calcium carbonate, a silicate, zinc, zinc sulfate, or mixtures
thereof.
8. A composition comprising: i) 60.1% to 99.9% by weight of a
moldable material composed of a plastic or polymer material wherein
0.1% to 39.9% of said 60.1% to 99.9% is bituminous material; and
ii) 0.1% to 39.9% by weight of a dense metallic material selected
from iron oxide, zinc sulfate, crushed stone, and glass fibers, or
a dense metallic material comprising zinc.
9. A composition comprising: i) about 90% by weight of a moldable
material composed of about 83% of an ethylene-vinyl-acetate
copolymer and about 17% of bituminous material; and ii) about 10%
by weight of iron oxide.
10. A consumable container for use in transport and/or
melt-processing operations according to any one of claims 1-7.
11. A consumable container according to claim 10, further
comprising a bitumen product contained in said container, wherein
the specific gravity of the composition is equal to or greater than
the specific gravity of the bitumen product contained therein at
the melting temperature of the bitumen product.
12. A consumable container according to claims 10 or 11, wherein
the container is formed by blow-molding, casting, injection
molding, the use of a forming apparatus, or combinations
thereof.
13. A consumable container according to any one of claims 10-12, in
the form of a sealable bag, barrel, box, bowl, or cylinder of any
suitable shape or size.
14. A film suitable for use in packaging according to any one of
claims 1-7.
15. A composition according to claim 8 wherein said dense metallic
material is iron oxide.
16. A composition according to claim 8 or 15 wherein said moldable
material composed of a plastic or polymer material is an
ethylene-vinyl-acetate copolymer.
17. A composition comprising: i) 60.1% to 99.9% by weight of a
moldable material composed of an ethylene-vinyl-acetate copolymer
wherein 0.1% to 39.9% of said 60.1% to 99.9% is bituminous
material; and ii) 0.1% to 39.9% by weight of a dense metallic
material.
Description
TECHNICAL FIELD
[0001] The invention relates to a consumable product packaging
compound composed of at least one packaging material, such as
polymers, plastics and extenders and the like, used in combination
with bituminous material. The packaging compound comprises a dense
metallic material, either pure in powder form or in the form of
salt or oxide that is physically and/or chemically combined with
the packaging material, so that the density of said material is
adjusted to prevent the material from floating to the surface of a
mixture of bituminous product and packaging material upon melting
of the bituminous product or in the molten bituminous product after
melting. The components of the packaging material are preferably
selected such that they are compatible with a bituminous product to
be packaged. After transport and storage, the packaging material
can be directly incorporated into the bituminous product for final
use without formation of a film (or "skin") that accumulates at the
surface of the molten material during a melt process.
BACKGROUND ART
[0002] Bitumen products (also known as asphalts), tars or resins
are well known materials used in many road building, construction,
and other industrial applications. The characteristic that bitumen
products have in common is that they are solid or semi-solid at
ambient temperature and liquid at elevated temperatures. For
transportation from source to end-use location, these materials are
either carried in bulk or in containers. When carried in bulk, they
should be maintained at such a temperature that their viscosity is
low enough to allow for easy pumping and transfer thereof. When
carried in containers, such as drums or pails of any size and
shape, their temperature, after filling, drops to ambient and the
product becomes solid or semi-solid. The containers are generally
transported and stored at ambient temperature. Before use, the
containers and the material they contain have to be heated-up or
melted to allow for the pouring, pumping and transfer of the
product. After heating, the container usually cannot be reused and
must be disposed of.
[0003] Bitumen product containers have to be solid enough for
handling and transport, and have to be able to be heated up before
the product can be used. For this purpose, they are usually made of
metal, most commonly steel, and are in the form of drums. The main
advantage of steel drums, compared with other types of similar
packaging, is that they are relatively inexpensive. There are,
however, at least three problems associated with using drum
containers. The first is that the drum containers have to be
disposed of after use. As they contain bitumen product, it is
almost impossible to clean them up for re-use and they therefore
become waste. The second is that, owing to the relatively high
viscosity of bitumen products, it is practically impossible to
empty the drums totally. As a result, it is usually considered that
up to 2 to 3% of the product left adhering to the walls of the
container is lost. This increases the amount of wastage material
released into the environment. The third problem relates to
transport cost and efficiency. Due to the loss of usable amount of
bitumen products through its adherence to the container walls, this
results in the need for an overestimation in the actual and final
useable weight of bitumen products. Accordingly, to make up for the
shortfall of useable bitumen one has to increase the volume of
product ordered, which increases the total weight of product
required to be transported.
[0004] To solve the problem of wastage and freight burden, a number
of solutions have been proposed, and a number of them utilizing
soft bag packaging as the container. In these cases, the bitumen
product is packed, while hot, into soft bags. Upon cooling down,
the bitumen product becomes solid or semi-solid at ambient
temperature, as does the whole of the package. Bags can then be
handled, stored, transported to the end-use location with freight
burden kept to minimum. The use of a polypropylene film to package
roofing asphalt has also been described (see U.S. Pat. No.
5,452,800).
[0005] While the solution of using plastic bagging or film
addresses one of the problems associated with steel drum packaging,
it is in itself a source for other problems. The two main reasons
relate to the density and then to the compatibility of the
container material with the bitumen contained therein. As
mentioned, bitumen products are required to be molten before
transfer and use. The plastic in contact with the bitumen product
cannot be removed, as it is firmly adhered to the outside of the
product. In order to access the bitumen product, it therefore has
to be melted together with its packaging.
[0006] The plastic is usually designed to melt at the melting
temperature of the bitumen product. However, this does not
necessarily mean that the plastic is compatible with the bitumen
product. Plastic or polymer products, such as those used in the
packaging industry, like polyethylene, polypropylene, polystyrene,
etc., are not easily dispersed in bitumen products. Not only does
it take quite a lot of shearing energy to achieve dispersion, but
it also requires the materials to be chemically compatible with
each other. As a result of incomplete dispersion throughout the
bitumen product, and due to the lower density of the plastic or
polymer materials compared with that of bitumen, the plastic
materials like polyethylene, polypropylene, and polystyrene migrate
towards the surface of the melting or molten bitumen material. Over
time, a film, or skin, of the plastic material so formed thickens
and rapidly becomes a source for severe operational problems.
Interestingly, however, the formation of this film has been viewed
as a beneficial outcome in that it is able to reduce the emission
of fumes from asphalt materials during the melting process (see
U.S. Pat. Nos. 5,733,616; 5,989,662; and 6,107,373, which, in
addition to describing the use of solid containers that melt with
asphalt, even describe the intentional addition of polymer material
to molten asphalt to form a skin to reduce fumes). See also WO
00/55280.
[0007] However, road-paving bitumens, having a significantly lower
softening point, are much softer than roofing bitumens. Road-paving
bitumens are therefore used and handled at significantly lower
temperatures in such a way that fumes generated during storage is
of much less concern that with roofing bitumens. In addition,
roofing bitumen is heated up on site and used in relatively small
quantities, whereas road-paving bitumen is used in much larger
quantities and stored in tanks of considerable size. A skin of
polymer materials generated by the packaging materials for
bitumens, as described above, would be undesirable in most cases of
road paving bitumen melting and storage. The high viscosity and low
density of such a polymer skin would make it very difficult to
remove or to consume. The skin would also arguably increase in
thickness at the surface of a tank or other container with each
load and over time, become too thick and therefore impossible to
remove. Additionally, road-paving bitumens, unlike roofing
bitumens, still flow at ambient temperature. This makes them more
difficult to package in suitable packaging material than roofing
bitumen.
[0008] In order to reduce the problem of polymer skin formation at
the surface of the molten bitumen material, several options have
been proposed like reduced packaging thickness or the use of double
layer packaging. In the case where the packaging material is kept
thin, such packaging becomes sensitive to puncturing and damage
during transport. This, in turn, results in leaks with all the
associated spillage problems. As a result, the main container
containing bags of bitumen products in thin bags can be badly
dirtied and a large part of the cargo can be spoiled with bags
being glued to each other. Also, and in the case of double layer
packaging, the outer layer has to first be peeled off and disposed
of before the melting process can take place. Peeling off the outer
layer can prove to be very difficult due to the thinness of the
inner layer, which frequently results in leakage of small amounts
of bitumen product into the space between the outer and inner
layers. This makes the peeling off of the outer layer impossible in
extreme cases. This results in more packaging (from the thicker
outer layer) accumulation at the surface of the molten bitumen,
causing associated operational problems, like product homogeneity,
pumping, pipe clogging, etc.
[0009] Modification of the characteristics of bitumen products by
the addition of polymers or plastic components is a well-known
field of technology and this has been described and discussed in
many publications, at international conferences, and in the
internal publications of several corporations. In the field of
bitumen technology, and as reported in publications from the ASTM
and the European Asphalt Pavement Association, it is today widely
accepted that polymers and plastic do not readily blend with
bitumen products, and that a mixing process using shearing energy
and compatibilization time is required before all the components
form an intimate blend.
[0010] Citation of the above documents is not intended as an
admission that any of the foregoing is pertinent prior art. All
statements as to the date or representation as to the contents of
these documents is based on the information available to the
applicant and does not constitute any admission as to the
correctness of the dates or contents of these documents.
Disclosure of the Invention
[0011] There is a definite need for bitumen product packaging that
is strong enough for ease of handling, transport and storage. Such
packaging should be economical enough to compete against other
types of packaging and should preferably incur little or no release
of wastage into the environment. It should ideally be compatible
with the material contained within it. More importantly, the
packaging material should have a higher density than that of the
contained material in order to prevent formation of a skin at the
surface of storage and/or heating tanks, thus facilitating
subsequent heating and melting processes.
[0012] The present invention provides a composition which may be
used as a packaging material for bitumen products. The composition
is composed of polymer material combined with a bituminous material
and a density increasing metallic charge. The polymer material is
preferably compatible with the bitumen product to be packaged. The
metallic charge is preferably at least one metal or the oxide or
salt thereof, in powder, salt, or oxide form.
[0013] With a higher density than that of the packaged material,
the packaging material sinks downwards as the packaged material
melts during a heating process. As the heating process progresses
until all material is molten, the packaging material slowly
releases its metallic charge as it melts and combines with the
packaged bitumen material. The time interval between reaching the
melting temperature and the final molten state of the packaging
allows the packaging material to swell and become incorporated
within the contained material. Optionally, the melting or molten
material may be mixed to increase the dispersion of the packaging
material. The quantity of non-incorporated packaging material
migrating to the surface is minimized, while the minimal amount of
packaging residue accumulates at the bottom of the vessel may be
flushed and further attempts at incorporating it into the packaged
material during recycling, pumping and transfer of the final
product can be made.
[0014] Therefore, and in a first aspect, the invention provides a
composition for forming containers or wrappings for bitumen
products, said composition comprising (i) 60.1% to 99.9% by weight
of a moldable material composed of a plastic or polymer material
wherein 0.1% to 39.9% of said 60.1% to 99.9% is bituminous
material; and (ii) 0.1% to 39.9% by weight of a dense metallic
material.
[0015] Bituminous material refers to matter composed of much
organic, and/or carbonaceous, substances that are mostly in the
form of tarry hydrocarbons. The material is usually soluble in
carbon disulfide, and includes bitumen products. A "bitumen
product" as used herein is employed to mean naturally occurring or
heat refined substances that are composed mainly of carbon and
hydrogen with little oxygen, nitrogen or sulfur. They are usually
dark brown or black mixtures of hydrocarbons such as asphalt, crude
petroleum, or tar. The term thus includes natural or synthetic
heavy petroleum or tar-derived products as well as road paving
bitumens, blown or oxidized bitumens, roofing bitumens,
polymer-modified bitumens, naturally occurring bitumens, refinery
bottom residues, de-asphalting rocks, petroleum-tars and coal-tars.
The term also encompasses raw or processed asphalt, including
asphalt bottoms from petroleum refineries, naturally occurring
bituminous materials, tars and pitches, or the air-blown or
chemically processed or treated forms of these same materials.
Non-limiting examples include air blown asphalt containing
catalysts such as ferric chloride, as well as conventional roofing
flux asphalts or paving-grade asphalts or specialty asphalts like
water-proofing asphalts and sealers. The invention may also be
practiced with blends of different kinds of asphalt or other
bitumen products. A bituminous material can be used in pure form or
in a chemically modified form.
[0016] The metallic material may be any source of metal ions
derived from at least one metal or the salts and oxides thereof.
Alternatively, it may be a metal complex composed of a metallic
material that has been combined with a plastic or polymer
material.
[0017] The composition optionally further comprises an extender
which maintains the relative amounts of the moldable material and
density increasing metallic material. Non-limiting examples of such
extenders include antioxidants, UV stabilizers, surfactants,
binders, colourants, and mixtures thereof.
[0018] In a particular embodiment of the invention, a composition
comprising (i) about 90% by weight of a moldable material composed
of about 83% of ethylene-vinyl-acetate copolymer a plastic or
polymer material and about 17% of bituminous material; and (ii)
about 10% by weight of iron oxide is provided.
[0019] Another aspect of the invention relates to the use of the
compositions of the invention as packaging materials. Preferably,
the density (or specific gravity) of the composition, and thus
packaging material, is greater than the density of the material
packaged therein. In one embodiment, the compositions of the
invention are used to produce consumable containers as packaging
material for use in transport and/or melt-processing operations,
particularly of bitumen products. Such containers may be in any
suitable shape or size, including, but not limited to a sealable
bag, barrel, box, bowl, or cylinder. The containers may be prepared
by any suitable process, including, but not limited to
blow-molding, casting, injection molding, the use of a forming
apparatus, or combinations thereof. The compositions of the
invention may also be used to make films of various thicknesses and
suitable for packaging.
[0020] Compared with previously used packaging material and
processes for packaging of bitumen products, the disclosed
invention provides the advantages including the following. In the
case of packaged bitumen products, the higher density of the
packaging material relative to the packaged bitumen products
reduces non-molten packaging material left floating in heating
vessels. This provides the benefit of avoiding subsequent
operational problems. Also, the presence of bituminous materials in
the packaging material can allow it to ultimately become
incorporated into the packaged bitumen products. Wastage and extra
freight burden on shipment due to the packaging material can be
reduced.
[0021] Moreover, the bituminous materials can be "pre-blended" in
preparing the compositions of the invention such that the resultant
packaging materials are "pre-compatibilized" for dispersion into a
bitumen product during a melting process. The "pre-blended" or
"pre-compatibilized" material allows for the design of thicker
walled containers and films, as well as reinforcement structures
within said containers, with virtually no risk of finding thicker,
non-dissolved or non-molten pieces of packaging material during a
heating and melting process. Thicker and stronger packaging
materials permits safer handling and longer storage time as well as
reduced risk of punctures and subsequent leakage.
[0022] Generally, the ability of the compositions of the invention
to be used in consumable packaging materials for bitumen products
reduces the need to dispose of used packaging materials, with any
residual amounts of bitumen products, into the environment.
[0023] In a further aspect of the invention, methods are provided
for the production of compositions as disclosed herein.
Modes of Carrytin out the Invention
[0024] The invention provides compositions of modified plastic or
polymer materials that contain a density increasing metallic
material to increase the specific gravity of the composition
relative to the plastic or polymer materials. The plastic or
polymer materials are blended with the density increasing metallic
material as described herein or via methods known in the field.
Preferably, the metallic materials increase the specific gravity of
the composition to be about 5%, about 10%, about 15%, about 20%,
about 25%, about 30%, or about 35% or more than the specific
gravity of a bitumen product of interest for packaging.
[0025] Generally, the plastic or polymer material used in the
practice of the invention is any that is compatible with the
material to be packaged and that is suitable for use as packaging
material formed from the compositions of the invention. The
compositions of the invention have the necessary physical
properties such that packaging materials formed therefrom have the
required toughness, impact resistance, temperature stability,
and/or flexibility.
[0026] Exemplary plastic or polymer materials for use in the
practice of the invention include, but are not limited to,
ethylene, propylene, ethylene-propylene copolymers, and butylene
copolymers. Alternatively, copolymers of acrylates and
methacrylates, such as butyl, propyl, ethyl, or methyl acrylate or
methacrylate copolymerized with ethylene, propylene, or butylene,
may also be used. Epoxy-functionalized copolymers such as a
terpolymer of ethylene, butyl acrylate and glycidyl methacrylate
may also be used to improve the impact-resistance and flexibility
of packaging materials made thereof. Natural or synthetic rubbers
may also be used; non-limiting examples include
styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR),
styrene-ethylene-butylene-styrene (SEBS), or terpolymer made from
ethylene-propylene diene monomer (EPDM). In one embodiment, the
material includes an ethylene-vinyl acetate copolymer with a vinyl
acetate content from about 5% to about 40% by weight, so that it is
soluble in asphalt or other bitumen products. Mixtures of the above
materials may also be used.
[0027] Particularly preferred plastic or polymer materials for use
in the invention are selected from polyethylene, polypropylene,
polystyrene, styrene-butadiene-styrene, styrene-butadiene,
styrene-indene-styrene, copolymers of acrylates and methacrylates,
ethylene-vinyl-acetate, atactic polypropylene, mineral or natural
or synthetic fibers, and mixtures thereof. Ethylene-vinyl-acetate
is especially preferred in the practice of the invention. In some
embodiments of the invention, the material is a random copolymer of
ethylene and unsaturated monocarboxylic acid that is neutralized
with a metal ion, but the invention may be practiced without the
use of plastic and polymer materials other than this neutralized
copolymer.
[0028] The density increasing metallic material of the compositions
is preferably a source of metal ions derived from at least one
metal or the salts and oxides thereof. The material is preferably
in the form of a powder, pellet or granule that can be blended with
the plastic or polymer material used. The metallic material
preferably comprises iron, calcium, zinc or silicon, although many
other density increasing metals may be used. Preferred metallic
materials include iron oxide, calcium carbonate, a silicate, zinc
sulfate, or mixtures thereof. Especially preferred is the use of
iron oxide. Other materials, such as crushed stone or glass fibers
may also be used. Particularly preferred in the practice of the
invention is any metallic material suitable to be present in a
bitumen product to be packaged. Also preferred are metallic
materials with high specific gravity, such as at least 2.7 (calcium
carbonate) or at least 5.0 (iron oxide).
[0029] The bituminous material present in the compositions may be a
bitumen product as described herein. It may also be a semi
air-blown bitumen or oxidized bitumen, such as bitumen used for
roofing and waterproofing applications. It may be advantageous to
maximize the amount of bituminous material in the compositions of
the invention where they are of a lower cost than the plastic or
polymer materials. Similarly, the amount of metallic material may
be minimized to only that necessary to produce a composition having
a slightly higher specific gravity than a bitumen product to be
packaged.
[0030] The compositions of the invention may be formed into a
variety of packaging materials, including containers of various
shapes and sizes. Examples of possible containers include those
described in U.S. Pat. Nos. 5,733,616; 5,989,662, and 6,107,373.
Other possible containers are those described in published
applications WO 98/39221, WO 99/30973, and WO 00/55280.
[0031] The compositions may also be formed into sealable bags or
films like that described in U.S. Pat. No. 5,452,800 for use in
packaging. The thickness of such bags or films may be readily
determined by the skilled person depending on the application to
which the bags or films are to be used. Thicknesses of at least
about 0.1 to 5 mm are within the scope of the invention.
[0032] The compositions, when used as a packaging material, should
have a softening point high enough to tolerate the temperatures of
a molten bitumen product. Preferably the material has a ring and
ball softening point higher than about 70.degree. C., more
preferably higher than about 90.degree. C., and even more
preferably higher than about 110.degree. C. The ring and ball
softening point may be measured by ASTM D36.
[0033] A container of the invention may be formed by any convenient
process. Without limiting the invention, the sidewalls of the
container can be bonded to the base. In preferred embodiments, the
container is formed as an integral or unitary structure by
injection molding, blow molding, rotation molding, or other molding
processes. As known to the skilled person, a molding process
usually involves the use of a heat-softened composition to be
molded. The heat-softened composition is injected, blown, or
otherwise formed via a mold into a desired shape and size. After
cooling and solidification, the composition takes the shape of the
mold cavity.
[0034] The containers of the invention can also be adapted to have
handholds, breakaway sections, recesses, and ribs to increase its
strength. The ribs may be internal or external to the container and
may also serve to provide stability of shape to the container. The
container should have sufficient strength to support molten bitumen
product without tearing or significant yielding.
[0035] As noted herein, the packaging materials of the invention
are consumable such that they would be incorporated into the
packaged bitumen product upon its heating or melting.
Advantageously, the packaging materials of the invention have a
higher specific gravity than the packaged bitumen product such that
the materials do not "float" to the surface of the product upon
heating. The materials are not "buoyant" in a melted or molten
bitumen product. This facilitates the dissolution and dispersion of
the packaging materials into the heated bitumen product.
[0036] The packaging materials are preferably used to contain
bitumen products as described herein. Non-limiting examples of such
products include asphalt, asphalt bottoms from petroleum
refineries, naturally occurring bituminous materials, tars and
pitches. They can also be a conventional roofing flux asphalt, a
paving-grade asphalt, water-proofing bitumen, battery compounds,
and sealers. These products may be air-blown or otherwise
chemically processed or treated. For example, the asphalt can be
air blown with catalysts such as ferric chloride and the like.
[0037] In one embodiment of the invention, the packaging materials
and asphalt contained therein has a solubility in trichloroethylene
of at least 99% such that it meets most international standards for
bitumen. The amount of metallic material in the packaging material
would thus be no more than 1% of the total weight of packaging
materials and asphalt.
[0038] The compositions and packaging materials of the invention
may be "pre-blended" with bituminous material to improve their
dissolution in bitumen products upon heating or melting.
"Pre-blending" refers to the incorporation of bituminous material
into the compositions and packaging materials before the latter are
to be dispersed into the packaged bitumen products.
[0039] The compositions of the invention are readily prepared by
combining a plastic or polymer material with bituminous and
metallic materials as described herein and/or by standard methods
in the field. The combination is preferably heated, and mixed or
blended, to form a homogenous composition comprising all three
materials. This blended material may be used directly to form
packaging materials of the invention or cooled for later use to
prepare packaging materials.
[0040] The compositions and packaging materials of the invention
preferably do not significantly alter the characteristics of a
bitumen product packaged therewith after the compositions and
packaging materials are dispersed into the product. As non-limiting
examples, bitumen products containing the dispersed composition or
packaging material differ from the same bitumen product without the
dispersed material by not more than about 3 to about 5% in
penetration (by 0.1 mm increments) at 25.degree. C. as determined
by ASTM D5; by not more than about 3 to about 20% in softening
point temperature as determined by ASTM D36; by not more than about
3 to about 10% in viscosity (by cSt) as determined by ASTM D445; by
not more than about 3 to about 10% in ductility (by cm) as
determined by ASTM D13; and by not more than 1% in
trichloroethylene solubility (by %) as determined by ASTM
D2042.
[0041] In accordance with a particularly preferred embodiment of
the invention, the composition of the packaging material is first
designed to be compatible with the contained bitumen product and in
a form suitable for its final intended use. The density of the
packaging material is adjusted by means of increasing or decreasing
the amount of metallic material added, such the density is higher
than that of the material to be packaged. The amount of metallic
material may be added in relatively small amounts in comparison to
the amount of packaging material. As there is provision in most
paving bitumen for a maximum allowable limit of 1% by weight of
insoluble matter, the amount of metallic charge should remain below
this limit in the final molten bitumen. The packaging material
would normally not xceed 5% by weight of the total packaged
product, most preferably about 3%. Therefore, there is sufficient
flexibility to adjust the content of metallic charge to ensure that
it does not exceed 1% of the total weight of the packaged
material.
[0042] The components of the packaging material are proportioned
and blended together at the suitable temperature to allow for
efficient mixing of all components. After mixing and
homogenization, the packaging mixture is then processed through
package forming devices, such as a blowing or film blowing machine,
an injection molding machine, a casting device or a forming machine
to produce containers of the desired form and shape. The size and
shape of the containers may take into account logistics constraints
and economical considerations. The molten bitumen product is
subsequently packaged in the produced containers using any suitable
filling device and allowed to cool therein.
[0043] In a preferred practice of the invention, the polymer or
plastic component of the packaging composition is made of bitumen
compatible polymer such as ethylene-vinyl-acetate or
styrene-butadiene-styrene which has been pre-blended with
bituminous material or derivatives thereof, such that it is
compatible with the bitumen product to be packaged. The bituminous
material can be bitumen of the same or of a different penetration
grade than the bitumen product to be packaged. The grade of paving
bitumens is generally determined by the penetration test, such as
the ASTM D-5 method. The grade is given as the depth in tenths of
millimeters of penetration of a needle at 25.degree. C., during 5
seconds and with a load of 100 grams. Typical paving grades are:
5/15-20/30-40/50-50/70-60/70-60/80-80/100-180/220-300/400. The
grade of oxidized bitumen is generally determined by the ring and
ball softening point test, such as the ASTM D36. Typical oxidized
grades are: 75/30-85/25-100/40-125/30.
[0044] Non-limiting examples of bituminous material are oxidized
bitumen, semi-blown bitumen, naturally occurring bitumen, refinery
heavy residues, heavy fuel-oil, extracts, petroleum-tar, coal-tar,
aromatic extracts, synthetic or natural resins, and mixtures
thereof.
Definitions of Terms Used herein
[0045] As used herein, the terms "comprise", "comprises",
"comprised" or "comprising" are to be interpreted as specifying the
presence of the stated features, integers, steps or components
referred to, but not to preclude the presence or addition of one or
more other feature, integer, step, component or group thereof.
Stated differently, and as used herein, the term "comprising" and
its cognates are used in their inclusive sense; that is, equivalent
to the term "including" and its corresponding cognates.
[0046] As understood generally, "density" is used herein to refer
to the measure of the mass of a unit volume of a substance. It is
thus "volumetric density" as opposed to "linear density" or "area
density".
[0047] "Specific gravity" as used herein refers to "relative
density" or a measure of how the density of one substance compares
with another. The "other" substance is most often pure water, with
a density of 1 kg per liter. "Specific gravity" has no units
because it is a ratio of two densities.
[0048] Unless defined otherwise all technical and scientific terms
used herein have the same meaning as commonly understood to one of
ordinary skill in the art to which this invention belongs.
[0049] The following examples are put forth so as to provide those
of ordinary skill in the art with a complete disclosure and
description of how to make and use the present invention, and are
not intended to limit the scope of what is regarded as the
invention nor are they intended to represent that the experiments
below are all and only experiments performed. Efforts have been
made to ensure accuracy with respect to numbers used (e.g. amounts,
temperature, etc.) but some experimental errors and deviations
should be accounted for. Unless indicated otherwise, parts are
parts by weight, molecular weight is weight average molecular
weight, temperature is in degrees Celsius, and pressure is at or
near atmospheric.
EXAMPLE 1
Preparation of Packaging Material for a Bitumen Product
[0050] A packaging material for bitumen product was prepared as
follows.
[0051] The packaging material was composed of 90 wt % of a mixture
composed of 8.3 parts of ethylene-vinyl-acetate copolymer, having a
melt-flow index of 8 (g/10 min) and 1.7 parts of bitumen having a
penetration of 60/70 1/10mm at 25.degree. C., and 10 wt % of
industrial grade iron oxide in fine powder form. After thorough
blending at 200.degree. C. of the components for about 1 hour, the
packaging material was manually formed into cylindrical containers
in molds of approximately 3 liters capacity. Thickness of the
containers were designed such as the total quantity of packaging
material was approximately 2.5 wt % of the total gross weight of
the final packaged material.
[0052] The specific gravity at 25.degree. C. of the components was:
TABLE-US-00001 Standard bitumen 60/70 penetration grade 1.03
Ethylene-vinyl-acetate, 8 MI 0.94 Iron oxide, approx. 5.0
Theoretical specific gravity of packaging material at 25.degree. C.
1.36 Measured specific gravity by hydrostatic balance at 25.degree.
C. 1.08
[0053] Without being bound by theory, the difference observed
between theoretical density and measured density is believed to be
due to (micro) air bubbles trapped into the packaging material
during preparation. While this air was not removed in this simple
process at laboratory scale, they may be readily removed or reduced
by use of industrial processes, including molding or injection
processes, under high pressure.
[0054] The specific gravity of the packaging material was therefore
higher than that of bitumen product. As such, the material is not
buoyant in comparison to the bitumen product.
[0055] A standard bitumen of penetration grade 60/70 1/10mm at
25.degree. C., heated up to about 90.degree. C., was poured into 5
of the containers. The containers were sealed and left to cool down
to ambient temperature for 24 hours. The five containers were
subsequently placed into a heating vessel of approximately 50 liter
capacity where the temperature was raised to about 140.degree. C.
by means of electrical coils. The observation of this experiment
was that the packaging material melted together with its content of
bitumen. After about three hours time, the whole of the bitumen and
its packaging was melted and there was hardly detectable packaging
material floating at the surface of the heating vessel. Based on
the above, there was only about 0.25 wt % of iron oxide added to
final molten bitumen. The whole of the molten material was
subsequently gently stirred for two minutes to ensure homogeneity.
Upon homogenization, a sample of the mixture was taken and tested
against a sample of the same neat bitumen having undergone the same
heat treatment but without packaging material. The results are
shown in Table 1. TABLE-US-00002 TABLE 1 Test results on bitumen
specimens Neat Packaged Test Method Unit Typical Bitumen Bitumen
Penetration at 25.degree. C. ASTM D5 0.1 mm 60 to 70 60 61
Softening point ASTM D36 .degree. C. 44 to 57 48.6 51.0 Viscosity
at 135.degree. C. ASTM D445 cSt nil 429.8 451.2 Ductility at
25.degree. C. ASTM D13 cm >100 >100 >100 Flash point, COC
ASTM D92 .degree. C. >232 344 342 Solubility in trichoroethylene
ASTM D2042 % >99 99.91 99.67 Thin Film Oven Test ASTM D1754 Mass
loss % <1.0 0.05 0.03 Retained penetration % >55 65.5
64.3
[0056] The results of Table 1 indicate that there is no adverse
effect of the packaging material on the packaged bitumen, which
maintains its characteristics well within the specifications of
most applications. The solubility in trichloroethylene is also well
maintained within usual specifications. The decrease in solubility
reflects the amount of iron oxide added to the packaging material
and this does not impair the overall characteristics of the sample
tested. The increase in softening point, arguably due to the
addition of the polymer contained in the packaging material, can
actually be considered as an improvement, as it is indicative of a
befter performance of bitumen at elevated temperature.
EXAMPLE 2
Calcium Carbonate as the Metallic Material
[0057] A second packaging material composition for bitumen product
was prepared with the following and had the following
characteristics (where "sp. gr." refers to specific gravity):
TABLE-US-00003 Ethylene vinyl acetate copolymer, MI of 35 g/10 min,
72% sp. gr of 0.94 Bitumen grade 60/70, sp. gr. of 1.03 15% Calcium
carbonate, industrial grade, sp. gr. of 2.70 13% Theoretical
specific gravity: 1.18 Measured specific gravity by hydrostatic
balance: 1.06
[0058] The ethylene vinyl acetate, bitumen, and calcium carbonate
components were thoroughly mixed together at a temperature of
approximately 200.degree. C. for three hours to enable for the
highest possible dispersion of the ingredients into each other. The
resulting material was processed through the same experiment as
described above and was used to package bitumen of penetration
60/70. The conclusion of the test was similar to that of Example 1.
There was no significant amount of packaging material floating at
the surface of the melting vessel upon the full melting process of
the packaged bitumen.
[0059] All references cited herein, including patents, patent
applications, and publications, are hereby incorporated by
reference in their entireties, whether previously specifically
incorporated or not.
[0060] Having now fully described this invention, it will be
appreciated by those skilled in the art that the same can be
performed within a wide range of equivalent parameters,
concentrations, and conditions without departing from the spirit
and scope of the invention and without undue experimentation. The
invention also includes all of the steps, features, compositions
and compounds referred to or indicated in this specification
(unless specifically excluded) individually, collectively, and any
and all combinations of any two or more of said steps or
features.
[0061] While this invention has been described in connection with
specific embodiments thereof, it will be understood that it is
capable of further modifications. This application is intended to
cover any variations, uses, or adaptations of the invention
following, in general, the principles of the invention and
including such departures from the present disclosure as come
within known or customary practice within the art to which the
invention pertains and as may be applied to the essential features
hereinbefore set forth.
* * * * *