Patent Application
20210185866
There are no related applications.
This invention was not made using federally sponsored research or development. The inventor retains all rights.
Not applicable.
This invention falls within the field of additives to polymer material to control its dielectric constant and preparing conductive additives for non-conductive material or to improve already conductive polymers. Placing a conductive pigment such as carbon black and graphene into an unsaturated polyester resin is already known to the art. (See e.g. Buhl et al. EP 0949633A1).
This invention provides a superior additive allowing a more precise control of the dielectric constant of a non-conductive polymer such as thermoplastics, unsaturated polyester, polyurethane or epoxy by the addition of planar graphite made into nanoparticles, or more particularly graphene. Saline in the form of an acrylate polymer is an additive that can create bonding with the polymer on one side of the molecule while the other side of the molecule can bond with a filler such as Aluminum Tri-Hydrate, Calcium carbonate, Aluminum Nitride etc. Carbon black can also be used together with the graphene and resin. Results achieved through the use of this additive include shielding of EMI, Elimination of ESD, increasing of conductivity, or the fine tuning of the dielectric constant within a needed range.
This invention provides a superior additive allowing a more precise control of the dielectric constant of a non-conductive polymer such as thermoplastics, unsaturated polyester, polyurethane or epoxy by the addition of planar graphite made into nanoparticles, or more particularly graphene. Carbon black, saline or acrylic can also be used together with the graphene and resin. Saline in the form of an acrylate polymer is an additive that can create bonding with the polymer on one side of the molecule while the other side of the molecule can bond with a filler such as Aluminum Tri-Hydrate, Calcium carbonate, Aluminum Nitride etc. Acrylate polymers are polymers of acrylate monomers which are in turn based on the structure of acrylic acid consisting of a vinyl group and a carboxylic acid ester terminus or a nitrile. A non-exclusive list of acrylate monomers that can be used to create acrylate polymers or co-polymers includes Methyl Methacrylate, Methacrylate, Methyl Acrylate, 2-Chloroethyl Vinyl Ether, 2-Ethylhexyl Acrylate, Hydroxyethyl Methacrylate, Butyl Acrylate, Butyl Methacrylate, and Trimethylolpropane Triacrylate. The additive can attach at one end to resin and at the other end attach to graphene or carbon black. Results achieved through the use of this additive include shielding of EMI, elimination of ESD, increasing of conductivity, or the fine tuning of the dielectric constant within a needed range.
The following is a non-exclusive list of substrates or polymers with which the invention can be produced: fiberglass, UPR resin, epoxy resin, polypropylene, polyurethane, PU/butadiene rubber, Nylon, PET. A different type of the saline additive would be used for each of these substrates to optimize the covalent bond formed with the polymer or acrylate type in order to form a three dimensional network that encapsulates all the graphene and improve conductivity. Such covalent bonds are close to the ionic bonds that are formed when a metal filler is used and they lead to the formation of a stable three dimensional structure comprised of the resin, graphene, carbon black, and polymer components that would not ordinarily bond in the absence of the saline.
Alternatively, the specific saline additive can be manipulated in order to improve the bonding. Different applications can be made in either thermoset or thermoplastic substrates and the additive can even sometimes strengthen the substrate material.
The mixture of graphene nanoparticles and resin can be used as a conductive additive for non-conductive materials such as fiber glass. These coated materials can in turn be assembled into laminar structures in various applications, with conductive and non-conductive layers both being present. The specific nature of the application can be changed by changing the dielectric constant of the laminate. Military and other applications are even possible by shielding of EMI. Anti-static applications such as anti-static coatings for storage tanks are possible because of the invention's elimination of ESD. Coatings produced with this invention can also give increased resistance to acidic conditions, etc.
In a preferred embodiment, the carbon black is ground to a size of 1 to 2 microns and then combined with the graphene. Damaged particles of graphene can lack electrons at certain places on the perimeter of the molecule and the carbon black can associate with the graphene in the three dimensional structure in order to supply or share electrons with the damaged graphene. Resistance can be reduced from 1023 ohms to 103 ohms. Less expensive graphene, which is mined rather than produced by the methane deposition process, often has such damage around the edges. The use of carbon black to supply missing electrons allows more effective use of such mined graphene.
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