AU2015222680A1

AU2015222680A1 - Flexible composite material and method of producing same

Info

Publication number: AU2015222680A1
Application number: AU2015222680A
Authority: AU
Inventors: Michael Vainer
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-02-27
Filing date: 2015-02-26
Publication date: 2016-09-15
Also published as: WO2015127496A3; WO2015127496A2; AU2015101952A4

Abstract

A rubber-plastic composite material is provided formed of rubber powders comprising poly-isoprene and/or butadiene and/or styrene and/or ethylene propylene diene monomer and/or chloroprene, or a combination thereof, mixed with polyolefin comprising polypropylene or polyethylene, or a combination thereof. The composite material provides the characteristics of flexibility, damping and insulation properties together with the characteristics of chemical resistance and polymer crystallinity. Carbon allotropes are also mixed into the material as required to additionally provide the characteristics of electrically conductive microstructures.

Description

FLEXIBLE COMPOSITE MATERIAL AND METHOD OF PRODUCING SAME

Field of the Invention

The present invention relates generally to the formation of new flexible composite materials composed of rubber powders and polyolefins, together with carbon allotropes as required.

More particularly, the present invention relates to a formation of flexible polymeric composite materials consisting of activated rubber powders, preferably consisting of poly-isoprene and/or butadiene and/or styrene and/or ethylene propylene diene monomer and/or chloroprene, combined together with a polyolefin, preferably polypropylene and/or polyethylene. Formation of the flexible polymeric composite materials is through application of blending/mixing technique on the said rubber powders and polyolefins to combine them into one mixture mass with dispersion of the said ingredients within. This said mixture mass lends itself to extrusion and/or moulding as required.

Additionally, the characteristics of the surface interplay properties created in the present invention during the process of combining the embodiment of the said rubber powders that have an activated surface area together with the polyolefin ingredients creates an optimal environment for simultaneous combination of the said activated surface area rubber powders and polyolefin ingredients with carbon allotropes, preferably carbon nanotubes and/or crystalline allotropes of carbon, thus leading to the formation of new flexible electrically conductive composite materials composed of rubber powders, polyolefins, and electrically conductive microstructures.

Background of the Invention

The discussion throughout this specification comes about due to the realisation of the inventor and/or the identification of certain related art problems by the inventor. Moreover, any discussion of material such as documents, devices, acts or knowledge in this specification is included to explain the context of the invention in terms of the inventor's knowledge and experience and, accordingly, any such discussion should not be taken as an admission that any of the material forms part of the prior art base or the common general knowledge in the relevant art in Australia, or elsewhere.

The main objective of the present invention is to provide a new flexible rubber-polyolefin composite material which combines the characteristics of flexibility, damping and insulation properties derived from the rubber powder ingredients together with the characteristics of chemical resistance and polymer crystallinity derived from the polyolefin ingredients, combined with the properties of electrically conductive microstructures as required. A further objective of the present invention is to alleviate at least one disadvantage associated with the related prior art.

Summary of the Invention

Rubber powders ingredients:

In one embodiment, the rubber powders ingredients are of size 0.6mm or smaller.

In another embodiment, the rubber powders ingredients exhibit an activated surface area.

In a preferred embodiment, the rubber powders ingredients are of size 0.6mm or smaller, and exhibit an activated surface area.

Where used herein the term ‘rubber powders’ is intended to be interpreted broadly, to refer to powders of materials including poly-isoprene and/or butadiene and/or styrene and/or ethylene propylene diene monomer and/or chloroprene or any combination thereof.

Where used herein the term ‘activated’ is intended to be interpreted broadly, to refer to rubber powders having a surface area that has undergone carbonization, has been exposed to oxidizing atmospheres, has been chemically treated with an acid, a strong base, or a salt, or has attained reactive carboxylic acid groups on the said surface area.

Polyolefin ingredients:

In one embodiment, the polyolefin ingredients are in pellet form of size 0.6mm or smaller.

In another embodiment, the polyolefin ingredients are of linear medium density.

In another embodiment, the polyolefin ingredients are polyethylene with a Melt Flow Index of no greater than 3.0 g /10min (ASTM D 1238 test method).

In a preferred embodiment, the polyolefin ingredients are a pellet form of 0.6mm or smaller sized linear medium density polyethylene having a Melt Flow Index of no greater than 3.0 g /10min (ASTM D 1238 test method).

Where used herein the term ‘polyolefin’ is intended to be interpreted broadly, to refer to a type of polyethylene and/or a type of polypropylene or any combination thereof.

Carbon allotropes ingredients:

Carbon allotropes are utilised within the present invention to create an electrically conductive flexible composite materials as required.

In one embodiment, the carbon allotropes ingredients are carbon nanotubes, such as for example, single walled carbon nanotubes, double walled carbon nanotubes and multi-walled carbon nanotubes.

In another embodiment, the carbon allotropes ingredients are crystalline allotropes of carbon, such as for example diamond or graphite or graphene.

In a preferred embodiment, the carbon allotropes ingredients are multi-walled carbon nanotubes.

Where used herein the term ‘electrically conductive’ is intended to be interpreted broadly, to refer to a material that permits the flow of electric charges in one or more directions, and can be associated with the presence and/or flow of electric charge ranging between static electricity and current electricity.

Blendinq/Mixing methodology:

In one embodiment, the rubber powders and polyolefin ingredients, together with carbon allotrope ingredients as required, are combined via utilisation of known injection moulding devices.

In another embodiment, the rubber powders and polyolefin ingredients, together with carbon allotrope ingredients as required, are combined via utilisation of known extrusion moulding devices.

In another embodiment, the rubber powders and polyolefin ingredients, together with carbon allotrope ingredients as required, are combined via utilisation of known high shear mixing devices.

In a preferred embodiment, the rubber powders and polyolefin ingredients, together with carbon allotrope ingredients as required, are combined via utilisation of known dynamic cavity mixing devices.

Where used herein the terms ‘blending’ and ‘mixing’ are interchangeable.

While it will be convenient to describe the present invention with reference to unused virgin manufactured rubber powder and polyolefin ingredients, the invention is specifically not limited to utilising that ingredient type and therefore ingredients derived from reclaimed end-of-useful-life rubber and polyolefin can also be similarly utilised.

Where used herein the term ‘end-of-useful-life’ ingredients is intended to be interpreted broadly, to refer to ingredients from material that is no longer required for its originally intended use or that is created as excess, over-run or a by-product of an industrial process.

Prior Art

Current known prior art flexible composite materials are: polytetrafluoroethylene laminate fabrics; silicone laminate fabrics; silicone rubber blocks; fibre reinforced rubber; and graphene-polyurethane composites.

The closest prior art flexible composite materials to the present invention include the following: • WO 96/04133, which provides a different material that incorporates fluoro-plastics as barrier components; • WO 98/31541, which provides a different material with fibre-reinforced elasticity properties; • US 20060420, which provides a different material with lubrication and oil-and-fat absorption properties; • US 20140918, which provides a different material with heat transfer properties for use in removing heat from electronic devices.

Current known prior art flexible electrically conductive composite materials are: nanocomposite membrane based on bacterial cellulose and polyaniline; interconnected graphene networks grown by chemical vapour deposition; infiltration of multi-walled carbon nanotube forests with polyurethane binder; and nanoparticle doped polydimethylsiloxane.

The closest prior art flexible electrically conductive composite materials to the present invention include the following: • WO 2013155453, which involves polymerizing aniline in the presence of oxidized carbon nanotubes followed by solution casting and flash welding; • US 20140299359, which involves providing a wet composition on a substrate and applying metallic nanowires followed by converting the wet composition into a coating; • WO2014062133, which utilises polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, photographic paper, insulated thermal tape, or a combination thereof; • WO 2012138803, which involves forming an aqueous suspension comprising carbon nanotubes and a surfactant; • US 201212313543, which involves a conductive electro-spun fibre portion; • WO2014186138, which utilises tetrafluoropropene.

However, no prior art provides the novel features of the new flexible composite material of the present invention, which enables the useful characteristics of flexibility, damping and insulation properties derived from the specifically utilised rubber powder ingredients to be combined together via bonding due to the activated surface area of the said rubber powder ingredients with the useful characteristics of chemical resistance and polymer crystallinity derived from the specifically utilised polyolefin ingredients, whilst also enabling electrical conductivity characteristics into the composite material to be derived from electrically conductive microstructures of carbon allotropes allowed to bond with the bonds of the activated surface area of the rubber powder ingredients and polyolefin ingredients within the composite material as required.

Importantly, no prior art also enables the use of end-of-useful-life ingredients to be similarly utilised within the present invention due to the specifically chosen materials of the present invention as well as the bonding mechanism and fabrication processes of the present invention for forming the flexible composite material mass. The present invention thereby enables utilisation of end-of-useful-life ingredients for the rubber powder ingredients, such as for example tyre crumb, and polyolefin ingredients such as for example high density polyethylene from plastic milk bottles, in order to similarly provide a flexible composite material of the present invention with the described useful material characteristics for industry of flexibility, damping and insulation combined with chemical resistance and polymer crystallinity, as well as electrical conductivity when required, at a significant reduction in material cost due to the utilisation of end-of-useful-life ingredients. A further advantage of the resultant flexible composite material of the present invention is its suitability for utilisation as a filament spool geometry as a substrate for cost effective additive manufacturing (3D printing) utilising, for example, Fused Deposition Modelling, for manufacture of, for example, flexible rubberised coils such as for example automobile engine mount main springs, and industrial tooling parts such as for example fly-wheels, with improved elastomeric properties, as well as incorporating electrical conductivity properties as required.

The present invention therefore provides a new flexible composite engineering material for advantageous wide-ranging industrial use together with a method of fabrication which can similarly utilise end-of-useful-life ingredients, and that is also simpler and less expensive than those of the prior art.

Description of the Drawings

Figure 1 is a photographic illustration of an extruded and pelletized master-batch flexible rubber-polyolefin composite material form of the mixture mass form of present invention.

Figure 2 is a photographic illustration of a compression moulded flexible rubber-polyolefin-carbon nanotubes composite material form of the mixture mass form of present invention, including depiction of a tensile test bar thus formed.

Figure 3 is a Scanning Electron Microscopy illustration of a cross-section of a compression moulded flexible rubber-polyolefin composite material form of the mixture mass form of the present invention, demonstrating the bonding interaction between the activated surface area of the rubber powders ingredients and linear medium density polyethylene.

Figure 4 is a Scanning Electron Microscopy illustration of a cross-section of a compression moulded flexible rubber-polyolefin-carbon nanotubes composite material form of the mixture mass form of the present invention, demonstrating the bonding interaction between the functionalised activated surface area of the rubber powders ingredients and the linear medium density polyethylene as well as the multi-walled carbon nanotubes.

Figure 5a is a photographic illustration of an extruded flexible rubber-polyolefin composite material filament form of the mixture mass form of the present invention.

Figure 5b is a photographic illustration of an extruded flexible rubber-polyolefin composite material filament form of the mixture mass form of the present invention having been wound onto a spool for utilisation in Fused Deposition Modeling (FDM) additive manufacturing.

Figure 6 is a photographic illustration of a fly-wheel manufactured by FDM additive manufacturing utilising the extruded flexible rubber-polyolefin composite material filament form of the mixture mass form of the present invention.

Figure 7 is a photographic illustration of a high-resistance low-conductance meter demonstrating the low resistance in Ohms of a compression moulded flexible rubber-polyolefin-carbon nanotubes composite material form of the mixture mass form of the present invention.

Description of the Preferred Embodiments

Further scope of applicability of embodiments of the present invention will become apparent from the detailed description given hereinafter. Flowever, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure herein will become apparent to those skilled in the art from this detailed description.

One embodiment of the present invention, where electrical conductivity is not required, is a rubber-polyolefin composite material comprised of rubber powders of size 0.6mm or smaller exhibiting an activated surface area together with pellets of 0.6mm or smaller sized linear medium density polyethylene having a Melt Flow Index of no greater than 3.0 g /10min (ASTM D 1238 test method),

Another embodiment of the present invention, where electrical conductivity is required, is a rubber-polyolefin-carbon nanotubes composite material comprised of rubber powders of size 0.6mm or smaller exhibiting an activated surface area together with pellets of 0.6mm or smaller sized linear medium density polyethylene having a Melt Flow Index of no greater than 3.0 g /10min (ASTM D 1238 test method) and also multi-walled carbon nanotubes in a neat or master batch form.

The said materials are combined together, preferably with the utilisation of a compatibility agent as is common in industry, such as for example a maleic anhydride grafted polypropylene (PP-g-MAFI) compatibility agent or a polyethylene grafted maleic anhydride (PE-g-MAH) compatibility agent, via a blending and/or mixing device, this being preferably a dynamic parallel twin-screw compounding device, into a malleable rubber-polyolefin composite material mass, or rubber-polyolefin-carbon nanotubes composite material mass, to be utilised by industry.

The resultant the flexible rubber-polyolefin composite material mass, or rubber-polyolefin-carbon nanotubes composite material mass for electrical conductivity when required, enables industrial uses requiring the material properties of flexibility, damping and insulation combined with chemical resistance and polymer crystallinity, as well as electrical conductivity when required, in for example a pelletized form as illustrated in Figure 1 for utilisation as a master-batch in industrial moulding and/or extrusion processes.

The rubber-polyolefin mass composite material, or rubber-polyolefin-carbon nanotubes mass composite material as required for electrical conductivity, of the present invention can be utilised directly in moulding applications by industry as illustrated in Figure 2 for uses such as moulding of flexible rubber-plastic composites material products such as for example insulation materials (thermal, acoustic and vibration damping), railway pads, computer motherboards, or radio-frequency identification tags when utilising rubber-polyolefin mass composite material, or such as for example capacitors, electrodes, or conductive plates when utilising rubber-polyolefin-carbon nanotubes mass composite material.

For further industry applications, the rubber-polyolefin mass composite material, or rubber-polyolefin-carbon nanotubes mass composite material as required for electrical conductivity, of the present invention can be utilised directly in extrusion applications by industry as illustrated in Figure 5a for uses such as extrusion of flexible rubber-plastic composites material filament products, such as for example flexible rubberised coils to be utilised for example as automobile engine mount main springs when utilising rubber-polyolefin mass composite material, or for example electrically conductive coil for flexible electronics or electromagnetic motors when utilising rubber-polyolefin-carbon nanotubes mass composite material.

Additionally, the rubber-polyolefin mass composite material of the present invention can also be utilised in the additive manufacturing (3D printing) industry for production of filament spool for utilisation in FDM additive manufacturing by industry as illustrated in Figure 5b for additive manufacturing of flexible rubber-plastic composites material products, such as for example, industrial tooling, such as for example industrial grippers or fly-wheels such as illustrated in Figure 6, whereby similarly, the rubber-polyolefin-carbon nanotubes mass composite material of the present invention can also be utilised in the 3D printing industry for production of filament spool for utilisation in FDM for additive manufacturing of flexible electrically conductive rubber-plastic composites material products, such as for example electronic circuits.

Claims

Claims defining the invention are as follows:

1. A rubber-plastic composite material comprising initially dispersed rubber powders combined with polyolefin being blended and/or mixed into a mixture mass form and thereafter extruded and/or moulded, wherein the rubber powders comprise poly-isoprene and/or butadiene and/or styrene and/or ethylene propylene diene monomer and/or chloroprene, or a combination thereof, and wherein the polyolefin comprises polypropylene or polyethylene, or a combination thereof.
2. The rubber-plastic composite material of claim 1, wherein the initially dispersed rubber powders exhibit an activated surface area, and the polyolefin is a linear medium density polyethylene having a Melt Flow Index of no greater than 3.0 g /10min (ASTM D 1238 test method).
3. The rubber-plastic composite material of claim 1 or claim 2, further including carbon allotrope ingredients comprising crystalline allotropes of carbon, such as diamond and/or graphite or and/or graphene, or single walled carbon nanotubes and/or double walled carbon nanotubes and/or multi-walled carbon nanotubes in neat or master-batch form, or a combination thereof.
4. The rubber-plastic composite material of any one of claims 1 through 3, wherein the initially dispersed rubber powders are of mean size of 600 microns or smaller, and/or wherein the polyolefin is in a pelletized form of mean size of 600 microns or smaller.
5. The rubber-plastic composite material of any one of claims 1 through 4, wherein the initially dispersed rubber powders are end-of-useful-life, and/or wherein the polyolefin is end-of-useful-life.
6. The rubber-plastic composite material of any one of claims 1 through 5, further comprising at least one compatibility agent selected from the group consisting of maleic anhydride (MAH), such as for example maleic anhydride grafted polypropylene (PP-g-MAH) or polyethylene grafted maleic anhydride (PE-g-MAH).
7. The rubber-plastic composite material of any one of claims 1 through 6, wherein the rubber-plastic composite material comprises from about 1 to about 70 weight percent of the initially dispersed rubber powders.
8. An article comprising of any one of claims 1 through 6 in which from about 1 to about 70 weight percent are initially dispersed rubber powders, and are combined with polyolefin; wherein the initially dispersed rubber powders comprise activated poly-isoprene and/or butadiene and/or styrene and/or ethylene propylene diene monomer and/or chloroprene, or a combination thereof, and wherein the polyolefin comprises polypropylene or polyethylene, or a combination thereof, the said article being manufactured by either traditional manufacturing and/or additive manufacturing (3D printing) means such as for example Fused Deposition Modeling (FDM).
9. The article of claim 8, wherein the article comprises an insulation material (thermal, acoustic and vibration damping), railway pads, computer motherboards, radio-frequency identification tags, or industrial tooling such as industrial grippers or fly-wheels, or flexible rubberised coils to be utilised for example as automobile engine mount main springs.
10. An article comprising of any one of claims 1 through 6 in which from about 1 to about 70 weight percent are initially dispersed rubber powders, and are combined with polyolefin and carbon allotrope; wherein the initially dispersed rubber powders comprise activated poly-isoprene and/or butadiene and/or styrene and/or ethylene propylene diene monomer and/or chloroprene, or a combination thereof, and wherein the polyolefin comprises polypropylene or polyethylene, or a combination thereof, and where the carbon allotrope comprises crystalline allotropes of carbon, such as diamond and/or graphite or and/or graphene, or single walled carbon nanotubes and/or double walled carbon nanotubes and/or multi-walled carbon nanotubes in a neat or master-batch form, or a combination thereof, the said article being manufactured by either traditional manufacturing and/or additive manufacturing (3D printing) means such as for example Fused Deposition Modeling (FDM).
11. The article of claim 10, wherein the article comprises a capacitor, an electrode, a conductive plate, or electrically conductive coil for flexible electronics or electromagnetic motors, or electronic circuits.
12. A method of preparing a rubber-plastic composite material curable mass comprising: • mixing from about 1 to about 70 percent by weight the initially dispersed rubber powders of the present invention in combination with the polyolefin of the present invention, and optionally a compatibility agent of the present invention, by utilising high shear mixers and/or dynamic cavity mixers and/or extruders and/or moulders and/or other such mixing devices as known in industry, to form a first mixture mass; and • extruding the first mixture in a single-screw or twin-screw extruder to form an extruded flexible rubber-plastic composite material, the said material being optionally pelletized; or • moulding the first mixture via compression moulding or injection moulding to form a moulded flexible rubber-plastic composite material.
13. The method of claim 12 further comprising: • mixing from about 1 to about 70 percent by weight the initially dispersed rubber powders of the present invention in combination with the polyolefin of the present invention and the carbon allotrope of the present invention, and optionally a compatibility agent of the present invention, to initially form the first mixture mass.
14. The method of claim 12 through 13, wherein at least some rubber powders of the present invention exhibit an activated surface area, at least some of the polyolefin of the present invention are a linear medium density polyethylene having a Melt Flow Index of no greater than 3.0 g /10min (ASTM D 1238 test method), and any of the carbon allotropes if added are at least to some proportion multi-walled carbon nanotubes.
15. The method of claim 12 through 14, wherein the first mixture mass comprises no more than 5% by weight of any maleic anhydride compatibility agent.