Patent Application
20080038083
As used herein, approximating language may be applied to modify any quantitative representation that may vary, without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about” and “substantially,” may not be limited to the precise value specified, in some cases.
As used herein, “shank” refers to the metal rod portion of a fastener, excluding the formed “head” and including the pointed end or a tip.
As used herein, “head” refers to the expanded head or portion for some embodiments of fasteners, which can be flat (giving a bigger target for the hammer) or countersunk (flat on top and slightly tapered on the bottom); smooth-faced or slightly “checkered” on top; cupped or slightly rounded; or duplex (with two heads, one above the other, making them easy to remove in temporary tasks like form building).
As used herein “nails” in either singular or plural form will be used interchangeably, referring to a fastening member having a pointed end or a tip (drill point). Examples include, but are not limited, to simple nails having a metal rod or shank, which is pointed at one end and a formed head at the other end; spiral shank nails (also called screw thread, Screw-Down® or “drive” nails) with spiral thread, which causes them to turn when they are driven like wood screws; rink shank nails (or Anchor-Down® nails), having an annular (or ring) thread on the nails for better holding power; fluted shank nails with horizontal threads to cut the masonry to minimize cracking and provide excellent holding power; and multi-pointed fasteners, typically referred to as staples.
As used herein, “threaded fastener” in either singular or plural form will be used interchangeably, referring to a fastening member (can be male or female) having a plurality of threads on the shank surface adapted for engagement with a mating fastener assembly. Examples include, but are not limited to, threaded screws, threaded nuts, threaded nails, etc. The term “threaded fastener” can also be used to refer to threaded joints on bikes, toys, electronic components, etc. and to threaded joints in steel pipes used for oil well drilling, etc. that need to come into intimate contact with another part to form a tight seal portion.
As used herein, “fastener” in either singular or plural form will be used interchangeably, referring to a fastening member in the form of a nail or a threaded fastener (male or female).
As used herein, the term “contact surface” refers to the surface area of the fastener to be fastened or in contact with the assembly, for example, the threaded surface 4 of a fastener such as in
The term “an effective amount,” as used herein, means an amount of the anti-seizing composition sufficient, with less resistance, for the fastener to be secured tightly with another fastening member, driven or screwed into a hole in a work piece, e.g., a wood or concrete surface for receiving the fastener, or a female thread formation holding screw for receiving the threaded fastener such as a screw having a drill point.
The anti-seizing compositions of the invention can be in the form of a powder, a solid wand or stick, a gel, a grease, an oil, a wax, an adhesive, a lacquer or varnish, a spray paint/slurry distributed as an aerosol spray or a suspension, the suspension media being water, organic solvents, organic polymers, inorganic polymers, etc. In one embodiment, the composition is applied as a stick, a wand, or a lump, or a powder, forming a coating layer directly on the threaded fastener. The compositions comprise ingredients generally used in products of this type, a spray paint, etc., well known to those skilled in the art, provided that they do not interfere with the boron nitride as the anti-seizing key ingredient described herein.
Anti-Seizing Active Ingredient—Boron nitride: Boron nitrides (BN), which can be used in the anti-seizing composition of the invention, are commercially available from a number of sources, including but not limited to, BN materials from GE Advanced Materials, Sintec Keramik, Kawasaki Chemicals, and St. Gobain Ceramics.
The BN can be in one of the following forms, or mixtures thereof, including: amorphous boron nitride (referred to herein as a-BN), boron nitride of the hexagonal system, having a laminated structure of hexagonal-shaped meshed layers (referred to herein as h-BN), a turbostratic boron nitride, having randomly-layered hexagonal-shaped meshed layers (referred to herein as t-BN). In one embodiment, the BN is in the form of turbostratic form, hexagonal form, or mixtures thereof.
In one embodiment, the BN particles have an average particle size of less than 100 μm. In a second embodiment, less than 50 μm. In a third embodiment, in the range of 10 to 30 μm. In a fourth embodiment, having a primary average particle size of less than 20 μm. In a fifth embodiment, the boron nitride has a primary average particle size ranging from 0.5 to 100 μm. In a sixth embodiment, the boron nitride has a primary average particle size ranging from 2 to 60 μm.
In one embodiment, the BN is surface-treated (“coated”) to further impart lubricating characteristics to the ingredient. Examples of surface coating materials for the boron nitride powder include, but are not limited to, isohexadecane, liquid paraffin, non-ionic surfactants, dimethylpolysiloxane (or dimethicone), a mixture of completely methylated, linear siloxane polymers which have been terminally blocked with trimethylsiloxy units, a silazane compound possessing perfluoroalkyl groups, a zirconate coupling agent, a zirconium aluminate coupling agent, an aluminate coupling agent, and mixtures thereof.
Anti-seizing Composition. The BN anti-seizing composition is applied in various forms, including, but not limited to, a boron nitride containing paint, a boron nitride containing lacquer, a boron nitride containing grease, a boron nitride thermal spray, a boron nitride stick or wand, a boron nitride containing cream, a boron nitride containing oil, and neat boron nitride powder. In one embodiment as illustrated in
In another embodiment, the composition is only applied on the drill point 22 of the fastener, such as a screw or a fluted shank nail of
In embodiments such as a paint, a lacquer, a grease, a cream, etc., the boron nitride anti-seizing material is mixed with a binder or carrier material, e.g., a water-soluble binder, organic-soluble binder, aqueous emulsion, paraffin, a liquid silicone, oil, etc. There is no special limitation to the binder material usable in the anti-seizing composition, so long as it does not interfere with the anti-seizing ability of the BN agglomerate/powder and has the retaining properties and binding abilities necessary for the agglomerate/powder. Examples of the binder materials include, but are not limited to, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, etc. In one embodiment, the ratio of boron nitride as the anti-seizing ingredient to the binder is such that the mass ratio of the boron nitride to binder is in the range of 0.3 to 9.0. In a second embodiment, the ratio is in the range of 0.5 to 8.0. In a third embodiment, the ratio is from 1.0 to 7.0. The combination and percentages of the binders are not critical, but the amounts and combinations should not be so large as to interfere with anti-seizing ability of the boron nitride, as noted above.
In one embodiment, e.g., a form of a thermal spray, the anti-seizing composition further comprises additives such as matrix-forming metal alloy is selected from the group of Ni, Co, Cu, Fe, Al, and combinations and alloys thereof, in a ratio of 1:6 to 9:1, by weight of boron nitride to the metal alloys.
The total amount of boron nitride in the finished anti-seizing formulation may be varied within wide parameters, but should be in an amount sufficient for the composition to have a coating layer containing boron nitride on the shank or the threads of the fastener, allowing the fastener to be easily driven into a surface, or screwed into a mating component (a screw or a nut) or a holding platform (e.g., wood, cement, metal surface) with no seizing, stoppage, or little resistance. This is the anti-seizing amount. Generally, in one embodiment, the anti-seizing effective amount of boron nitride is in the range of 0.1 to 99.9 wt. %, based on the total weight of the anti-seizing formulation In another embodiment, from 1 to 95 wt. %. In a second embodiment, the amount ranges from 2 wt. % to 75 wt. %. In a third embodiment, from 5 wt. % to 50 wt. %. In a fourth embodiment, this amount is less than 15 wt. %. In a fifth embodiment, this amount ranges from 5 to 30 wt. %.
In addition to the boron nitride component as the principal anti-seizing ingredient and optionally at least one binder/carrier component, depending on the form of the application (grease, lacquer, etc.), the composition can also contain a variety of additives known in the art, including, but not limited to, agitants, dyes, colorants, preserving agents, other co-lubricants such as MoS2, graphite or PTFE, corrosion inhibitors, or etc.
In one embodiment for use with nails as fasteners, i.e., for driving nails such as smooth nails or fluted shank nails, the composition further comprises up to 50% of cubic boron nitride (cBN) for a composition which makes the nails easier to drive (anti-seizing effect from the hBN) but also with increased holding power and strength (from the cBN). In a second embodiment, the amount of cBN is in the range of 2 to 40 wt. % of the total “boron nitride” composition. In a third embodiment, the amount of cBN is between 5 to 30 wt. % of the total BN composition. In a fourth embodiment, in addition to or in place of cBN, the anti-seizing composition further comprises at least one ingredient of talc, glass fiber, and milled glass in an amount of 2 to 50 wt. % of the total anti-seizing composition. In a fifth embodiment, the composition comprises 5 to 10 wt. % of at least one ingredient of talc, glass fiber, and milled glass.
In one embodiment, the anti-seizing composition contains boron nitride particles. Examples include BN powder comprising agglomerates of hBN platelets, with an agglomerate size distribution of from about 10 to about 125 μm. In another embodiment, the anti-seizing powder composition consists essentially of hBN platelets having an aspect ratio of from about 10 to about 300. In a third embodiment, the anti-seizing powder composition consists essentially of hBN particles having an oxygen content from 0.2 to 2.5 wt %. In a fourth embodiment, the anti-seizing powder composition consists essentially of hBN particles having a graphitization index of less than 7.
In one embodiment, the anti-seizing composition is in the form of a boron nitride liquid, e.g., a BN paint with high lubricity as well as good adherence to the threaded surface of the fastener, leaving a dried composition containing boron nitride. In one embodiment, the boron nitride anti-seizing composition is in the form of a BN paint containing 50-100 parts by weight of BN; 25-75 parts by weight of acrylic such as vinyl acrylic; and 100-200 parts by weight of a volatile liquid, such as an alcohol.
In one embodiment, the anti-seizing compound is in the form of a BN lacquer, e.g., in a binder of a film-forming substance such as a nitro lacquer, a solution of nitrocellulose in amylacetate. In a second embodiment, the anti-seizing lacquer comprises an organosilane compound as a binder, e.g., a solgel material, are usually made by hydrolysis of silanes forming Si—OH groups, which are coupled towards Si—O—Si bonds upon curing. In a third embodiment, the anti-seizing lacquer composition comprises BN powder in an aqueous binding agent mixture comprising a water dilutable resin, such as a modified polyester, and a water miscible hydroxyurethane. In a fourth embodiment, the anti-seizing lacquer composition comprises boron nitride in a binder of dispersant methyl methacrylate polymers and a graft copolymer.
The BN anti-seizing composition can be applied in a liquid form directly to the shank or the threaded surface using a conventional liquid application technique such as washing, brushing, or spraying using an aerosol can, a sprayer, or the like. In yet another embodiment, a fastener such as a screw, a straight nail, or a fluted nail is dipped into a bath of boron nitride paint or lacquer for a sufficient amount of time for a coating containing BN to cover the threaded surface. The fastener is removed from the dipping bath, wherein the BN composition dries out forming an anti-seizing coating.
Anti-seizing compositions in a form similar to BN paints can be obtained commercially from a number of sources, including GE Advanced Materials of Strongsville, Ohio.
In one embodiment, the anti-seizing composition is in the form of a wand, a stick, or a block. In applications, the block is rubbed against the shank or the threaded surface of the fastener (or vice versa, for the threaded screwed to be rubbed against the block), leaving a residue coating consisting essentially of boron nitride.
In one embodiment, the solid block contains 5-99 wt. % boron nitride, optional lubricants including molybdenum disulfide of 0-50 wt. %, calcium carbonate of 5-50 wt. %, optional minerals including mica, sericite, and talc in 0 to 30 wt %.
In yet another embodiment, the anti-seizing composition employs BN as the primary solid component, for a block comprising 0-99.9 wt. % of h-BN, 0 to 99 wt. % of t-BN. In one embodiment, the block is formed using the following process: a mixture of high oxygen t-BN and optional carbon additive is first cold pressed via a known method such as uniaxial pressing, filter pressing, or isostatic pressing, then heated to a temperature of 1500-2300° C. for 1 to 40 hrs., forming a block of sintered BN, having a density ranging from 0.20 to 1.50 g/cm3.
In yet another embodiment, the anti-seizing block employs synthetic wax, paraffin, or an organophosphate such as triphenyl phosphate as a carrier. The BN anti-seizing component is added to the melted liquid carrier, then the mixture thus formed is poured into molds, where the mixture is allowed to cool and the carrier allowed to solidify. The molds can produce a bar or other desired shape. Optionally, the melted mixture can be poured into a mold and compressed at pressures between 250 to 1500 psig.
In another embodiment, the anti-seizing block employs synthetic or natural wax, paraffin, or an organophosphate such as triphenyl phosaphate as a carrier. The BN anti-seizing component is dry blended with the carrier component, using a v-blender, and the dry mixture is charged into a mold heated to 250° F. and pressed at a pressure of between 250 and 1500 psig, cooled to room temperature, and de-moulded to form a bar or other desired shape.
In one embodiment, the anti-seizing composition is in the form of a grease (or oil), which can be applied onto the shank or threaded surface of the fastener via dipping, brushing, etc.
In one embodiment, the anti-seizing composition is in the form of a grease, containing 1-30 wt. % of the boron nitride active ingredient in a carrier of a mineral or synthetic oil. The grease composition in one embodiment further comprises at least one of a mineral thickener, such as acetylene black, talc, clay or silica, or a lithium soap, aluminium soap, other metal complex soaps, or polyurea in an amount of 2 to 30 wt. %.
The anti-seizing lubricant comprising BN can be made by processes known in the art, i.e., with the mixture being blended at room temperature. In one embodiment and depending on the binder(s) used, the mixture can be further treated by curing at a temperature between 200° to 500° C. from about 5 minutes to 24 hours.
In one embodiment, particularly for applications on large sized threaded joints, such as pipe joints for oil well drilling and the like, the composition is in the form of a thermal spray.
In one example of an anti-seizing thermal spray, the spray comprises 50 wt. % BN in a matrix-forming metal alloy of NiCrAl. The thermal spray is applied onto the threaded surface of the fasteners using a combustion or plasma or electric arc to produce the heat for melting of the composition in powder form onto the threaded parts. The composition, besides its anti-seizing characteristics, further provides structural strength to threaded parts to at least an operating temperature of 815° C.
The invention is further illustrated by the following non-limiting examples:
A mixture comprising 29.4 wt. % h-BN powder with an oxygen content of 0.3 wt % (grade AC6004 from GE Advanced Materials), and 68.6 wt. % of t-BN with an oxygen content of 15 wt %, and 2 wt. % of carbon black (grade N991 from Cancarb) is homogenously blended together. The blend is pressed in a uniaxial press to form a billet. The billet is cut into a plurality of blocks. The blocks are then sintered for 10-30 hours at 1700-2300° C., forming low-density BN blocks with density ranging from 0.20 to 1.5 g/cm3, and with a fired O2 concentration of <1.0 wt %.
In this example, a threaded joint for a steel pipe as illustrated in
In a comparable example using a threaded pipe that is not coated with the anti-seizing composition of the invention, seizing occurs half-way through the threading.
In this example, a threaded screw 10 as illustrated in
In a comparable example with a similar screw without any BN anti-seizing coating, the electric screwdriver slips off the screw head 11 when seizing occurs, and the screw stops half-way without proceeding any further. In some cases, the uncoated screws twist and break in two pieces.
Screws are inserted in a fixture to prevent the head of the screw from being coated with BN. The threads of the screw are coated using a water-based BN paint in a paint sprayer. The paint contains 9.4% h-BN, 5.1% aluminum oxide, and 1.6% bentonite clay, with the remainder of the composition present as water. The fixture is turned so that an even coating is applied over the threaded surface. The coating is applied at a thickness of 1-2 mil. An electric screwdriver is then used to drive the screws into a wooden bench. The screws go in all the way without seizing and/or breaking.
Smooth nails are inserted in a fixture to prevent the heads of the nails from being coated with BN. The shanks of the nails are coated using a BN aerosol spray paint. In the dried form, the paint contains 58% h-BN and 42% organoclay binder. A hammer is used to manually drive the nails into a wooden bench. The nails go in all the way, at least 10% quicker than nails without BN coating, using the same force on the hammer.
In this example, the screw has an electrical potential applied to the screw, which is sufficiently different from the BN powder dispensing equipment, thus causing the BN powder to be attracted to the screw surface. The composition being dispensed also contains a binder at a level of 0.5-20 wt %. Optionally, the composition may be thermally treated to secure it onto the screw.
Fluted shank nails are dipped into a suspension of BN powder in a volatile solvent system containing a dissolved polymer. A stirred suspension BN powder is prepared at a loading of 40-50 wt % in a mixture of acetone/low molecular weight crystal polystyrene, at a ratio of 40:60 by weight. The nails are either dipped into this mixture or placed in a fixture and the mixture is flow coated over the fluted shank region.
A portion of BN powder is placed into a suitable container, such as a bag or box, and a plurality of spiral shank nails are added. The entire apparatus is then vigorously agitated such that the BN powder falls onto the spiral threaded area of the nails. An electric screwdriver is then used to drive the spiral shank nails into a wooden bench. The nails go in all the way without seizing and/or breaking.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims, if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
All citations referred herein are expressly incorporated herein by reference.
This application claims the benefits of U.S. 60/807,528 filed Jul. 17, 2006, which patent application is fully incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60807528 | Jul 2006 | US |
