Micronized composite powder additive

Abstract

A solvent-free composite powder comprising at least one thermoplastic material and at least one submicron nanoparticle material.

Claims

1. A powder comprising: homogenous composite particles; said homogenous composite particles comprising at least one thermoplastic material and at least one submicron nanoparticle material; wherein said at least one thermoplastic material comprises from about 50 to 99 weight percent of said powder; wherein said at least one submicron nanoparticle material comprises from about 1 to 50 weight percent of said powder; wherein said powder is solvent-free.

2. The powder of claim 1, wherein said at least one thermoplastic material is a polymer, plastic, or wax, which can be melted and reformed.

3. The powder of claim 2, wherein said at least one submicron nanoparticle material is a nano-aluminum oxide, nano-titanium oxide, or a nano-graphene oxide.

4. The powder of claim 1, wherein said at least one submicron nanoparticle material has a mean particle size below 1,000 nm.

5. The powder of claim 1, wherein said homogenous composite powder has a maximum particle size below 1,000 microns.

6. The powder of claim 1, wherein said homogenous composite powder has a mean particle size ranging from 0.1 to 44 microns.

7. A composite powder comprising: at least one thermoplastic material; and at least one submicron nanoparticle material; wherein said at least one submicron nanoparticle material is dispersed in said at least one thermoplastic material homogenously.

8. The composite powder of claim 7, wherein said composite powder has a maximum particle size below 1,000 microns.

9. The composite powder of claim 7, wherein said composite powder have a mean particle size ranging from 0.1 to 44 microns.

10. The composite powder of claim 7, wherein said at least one submicron nanoparticle material has a mean particle size below 1,000 nm.

11. The composite powder of claim 7, wherein said at least one thermoplastic material is a polymer, plastic, or wax, which can be melted and reformed.

12. The composite powder of claim 11, wherein said at least one submicron nanoparticle material is a nano aluminum oxide.

13. The composite powder of claim 12, wherein said composite powder is used as a coating additive to improve surface durability.

14. The composite powder of claim 7, wherein said at least one submicron nanoparticle material is a nano titanium oxide.

15. The composite powder of claim 14, wherein said composite powder is used as an additive in personal care products to improve SPF protection.

16. The composite powder of claim 7, wherein said at least one submicron nanoparticle material is a graphene oxide.

17. The composite powder of claim 16, wherein said composite powder is used as an additive to improve corrosion resistance in a surface coating.

18. The composite powder of claim 16, wherein said composite powder is used as an additive to improve electrostatic dissipation in a surface coating.

19. A powder comprising: homogenous composite particles; said homogenous composite particles comprising at least one thermoplastic material and at least one submicron nanoparticle material; wherein said at least one thermoplastic material comprises from about 50 to 99 weight percent of said powder; wherein said at least one submicron nanoparticle material comprises from about 1 to 50 weight percent of said powder; wherein said powder is produced by dry mixing, melting, cooling, pelletizing, and compressing said composite particles.

20. The powder of claim 19, wherein said at least one thermoplastic material is a polymer, plastic, or wax, which can be melted and reformed.

21. The powder of claim 19, wherein said at least one submicron nanoparticle material is a nano-aluminum oxide, nano-titanium oxide, or a nano-graphene oxide.

22. The powder of claim 19, wherein said at least one submicron nanoparticle material has a mean particle size below 1,000 nm.

23. The powder of claim 19, wherein said homogenous composite powder has a maximum particle size below 1,000 microns.

24. The powder of claim 19, wherein said homogenous composite powder has a mean particle size ranging from 0.1 to 44 microns.

25. The powder of claim 1, wherein said at least one submicron nanoparticle material has a mean particle size below 500 nm.

26. The powder of claim 7, wherein said at least one submicron nanoparticle material has a mean particle size below 500 nm.

27. The powder of claim 19, wherein said at least one submicron nanoparticle material has a mean particle size below 500 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic flow diagram illustrating a method of producing the composite powder.

(2) FIG. 2 is a schematic flow diagram illustrating another method of producing the composite powder.

DETAILED DESCRIPTION

(3) The present teachings are described more fully hereinafter with reference to the accompanying drawings, in which the present embodiments are shown. The following description is presented for illustrative purposes only and the present teachings should not be limited to these embodiments.

(4) In compliance with the statute, the present teachings have been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the present teachings are not limited to the specific features shown and described, since the systems and methods herein disclosed comprise preferred forms of putting the present teachings into effect.

(5) For purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding. In other instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the descriptions with unnecessary detail.

(6) In this invention, thermoplastic material is broadly defined as any substance (such as, but not limited to, polymer, plastic, natural wax) that can be melted, liquefied, softened, or otherwise modified such that it can be homogenously combined with the submicron or nanoscale material, solidified, and micronized into a fine powder. Examples include, but are not limited to, polymers including polyethylene, polypropylene, polyamide, polyester, natural waxes such as carnauba wax, and synthetic waxes such as Fischer-Tropsch wax.

(7) In this invention, submicron nanoparticle material is defined as a particle with a mean particle size below 1,000 nm. Preferably, the submicron nanoparticle material is below 500 nm. Most preferably, the submicron nanoparticle material is below 100 nm.

(8) In this invention, the composite powder has a maximum particle size below 1,000 microns. Preferably, the composite powder has a mean particle size ranging from 0.1 to 44 microns. More preferably, the composite powder has a mean particle size of 5-20 microns with a maximum particle size of 44 microns. Most preferably, the composite powder has a mean particle size of 8 to 12 microns with a maximum particle size of 31 microns.

(9) In this invention, sufficient time is defined as a time long enough to homogenize the submicron nanoparticle material with the thermoplastic material matrix to form a molten composite.

(10) In this invention, sufficient temperature is defined as a temperature high enough to convert the dry mixture into the molten composite.

(11) In this multi-step process, the thermoplastic material is selected to serve as the matrix for the composite powder. This thermoplastic material can then be melted and combined with the submicron nanoparticle material using sufficient energy to wet, separate, and disperse the submicron nanoparticle materials homogenously throughout the thermoplastic material matrix. This thermoplastic composite can then be size reduced and supplied as an easy to disperse powder.

(12) In the first step the thermoplastic material component(s) are first combined with the submicron and/or nanoscale material by melt mixing, extrusion, or other processes familiar to those skilled in the art. In the second step, this thermoplastic composite material is size reduced using air micronization (irregular fine particles), mechanical milling (irregular coarse particles), spray melt congealing (spherical coarse and/or fine particles) or other processes familiar to those skilled in the art. In the case of spray melt congealing, the two steps can be combined. The result is a micronized thermoplastic composite powder that no longer contains free submicron or nanoscale material. This affords the ability to incorporate submicron and/or nanoscale materials into a wide range of products without the complexity, risks, and difficulties long associated with the use of these materials.

(13) Referring now to FIG. 1, the figure shows, by way of a non-limiting example, a schematic flow diagram illustrating a method of producing the composite powder 100. In the first step, the thermoplastic material is combined with the submicron nanoparticle material(s) in a ribbon blender to form a dry mixture 102. In the second step, the dry mixture is fed into the hopper of a twin screw extruder and processed under sufficient time, temperature and torque to form a molten composite 104. In the third step, the molten composite is discharged into a flaker to form a dry composite 106. In the last step, the dry composite is fed into a jet micronization mill and the size is reduced to desired particle size 108.

(14) Referring now to FIG. 2, the figure shows, by way of non-limiting example, a schematic flow diagram illustrating another method of producing the composite powder 200. In the first step, the thermoplastic material combined with the submicron nanoparticle material(s) in a jacketed and heated mixing vessel to form a dry mixture 202. In the second step, the dry mixture is heated and agitated under sufficient time, temperature and torque to form a molten composite 204. In the third step, the molten composite is discharged into a flaker to form a dry composite 206. In the last step, the dry composite is fed into a jet micronization mill and the size is reduced to desired particle size 208.

EXAMPLES OF COMPOSITE POWDERS

Example 1

(15) Aluminum Oxide/Polyethylene/PTFE Micronized Thermoplastic Material Nanocomposite

(16) Step 1:

(17) The following components are combined using extrusion melt mixing:

(18) 85% polyethylene wax (molecular weight approximately 2,000)

(19) 15% polytetrafluoroethylene (mean particle size 4.0 m)

(20) 5% fumed aluminum oxide (primary particle size between 7-40 nm).

(21) Step 2:

(22) The composite material from Step 1 is cooled, crushed, and micronized, using a jet mill, to a mean particle size (my) of 3.5-5.5 m and a maximum particle size (D100) of 15.56 m.

(23) This composite powder is useful to improve scratch and abrasion resistance when used as an additive in industrial paints, inks, and coatings.

Example 2

(24) Titanium Dioxide/Synthetic Wax Micronized Thermoplastic Composite

(25) Step 1:

(26) The following components are combined using extrusion melt mixing:

(27) 95% synthetic wax (molecular weight approximately 1,100)

(28) 5% 15 nm titanium dioxide

(29) Step 2:

(30) The composite material from Step 1 is cooled, crushed, and micronized, using a jet mill, to a mean particle size (mv) of 8.0-12.0 m and a maximum particle size (D100) of 31.11 m.

(31) This composite powder is useful as an SPF booster when formulated into skin creams and lotions.

Example 3

(32) Polypropylene/Graphene Oxide Micronized Thermoplastic Composite

(33) Step 1:

(34) The following components are combined using extrusion melt mixing:

(35) 50% polypropylene wax (molecular weight approximately 10,000)

(36) 50% graphene oxide (nominal particle size of 400 nm, 90% of particles below 800 nm in diameter)

(37) Step 2:

(38) The composite material from Step 1 is cooled, crushed, and micronized, using a jet mill, to a mean particle size (mv) of 10-12 m and a maximum particle size (D100) of 31.11 m.

(39) This composite powder is useful at improving corrosion resistance when used as an additive in coatings applied to steel and other metal surfaces.

(40) In all three examples the composite powder can be produced using various methods.

(41) In one method the thermoplastic solid material (in the form of flakes, pellets, etc.) are physically combined with the submicron nanoparticle material in a ribbon blender or other suitable dry blending machine. The dry mixture is fed into the hopper of a horizontal twin screw extruder, and processed under time, temperature, and torque conditions suitable to homogenously disperse the submicron particle in the molten thermoplastic. The molten composite is discharged into a flake, pellet, or prill. This dry composite material is fed into a jet micronization mill and size reduced to the desired particle size (mean and maximum size).

(42) In another method the thermoplastic solid material (in the form of flakes, pellets, etc.) are physically combined with the submicron nanoparticle materials in a jacketed and heated mixing vessel equipped with agitation. The dry mixture is gradually heated to melt the polyethylene, and is then agitated under sufficient time, temperature, and torque, to homogenously disperse the submicron particle in the molten thermoplastic. The molten composite is discharged onto a flaker belt or through and priller or pelletizer, to form a flake, pellet, or prill. This dry composite material is fed into a jet micronization mill and size reduced to the desired particle size (mean and maximum size).

(43) In this second method after the mixture is heated and agitated, the molted mixture is sprayed through a fine orifice into a cooling tower, where the molten composite exits the orifice, cools, and forms a spherical particle. The particles can be further size classified using screens or other techniques to refine the particle size distribution. The molten composite is sufficiently cooled when the molten composite becomes a hard and tack free solid such as a flake, prill, or pellet.

(44) While the present teachings have been described above in terms of specific embodiments, it is to be understood that they are not limited to these disclosed embodiments. Many modifications and other embodiments will come to mind to those skilled in the art to which this pertains, and which are intended to be and are covered by both this disclosure and the appended claims. It is intended that the scope of the present teachings should be determined by proper interpretation and construction of the appended claims and their legal equivalents, as understood by those of skill in the art relying upon the disclosure in this specification and the attached drawings.