Static structures (e.g. – buildings) – Processes – Barrier construction
Reexamination Certificate
1999-01-08
2001-07-03
Kent, Christopher T. (Department: 3635)
Static structures (e.g., buildings)
Processes
Barrier construction
C052S784100, C052S784150, C052S784160, C052SDIG009, C264S068000, C264S343000, C264S911000, C264S914000
Reexamination Certificate
active
06253527
ABSTRACT:
FIELD OF THE INVENTION
This invention relates particularly to products of the type which presently are formed with wood, or use wood, plywood or other board or the like as the supporting substructure or base.
BACKGROUND OF THE INVENTION
There are at present a large number of products which are formed with wood or use wood, plywood or the like as a structural component, substructure, or base to provide the requisite physical properties such as tensile and structural strength, rigidity and shape to which surface attachments, covers, or coatings can be screwed, nailed, glued or otherwise fastened, applied or attached.
Typical examples include insulated steel doors which use a perimeter frame of wood to which steel sheeting is applied on opposite sides thereof and the frame then filled with foamed insulation.
Other examples include wood door and window frame profiles whose exposed surfaces may be painted, covered or clad, for instance, with plastic or aluminium, or wood clad door panels used in folding or swing doors for garages or for truck or other vehicle doors and the like.
With such present products, the physical properties of the available components or substructures are relatively limited being determined by the selection of the wood, plywood or other board which is produced by conventional manufacturing processes.
Moreover, substantial wastage of wood by splintering, warping or by virtue of imperfections occurs in the manufacturing processes, and often the final product is subject to water absorption, warping, delamination and rotting.
Further, if other than conventional regular shapes of such materials, such as square or rectangular, are required for their end use, such shapes must be fabricated by sawing, cutting and/or assembling individual pieces and securing them together with nails, screws or other fastening means.
Composite materials which can be molded or processed into products have been proposed. For example, U.S. Pat. No. 5,075,057, issued Dec. 24th, 1991, discloses producing a product in which scrap plastic material containing some themoplastic material is shredded, milled and homogenized into a free flowing powder which is then warmed by subjecting same to heat to a temperature below the softening temperature of the plastic. This heated free flowing powder is then dry blended with filler material which preferably is heated or pretreated, eg. with chemicals. The dry blend is then compression molded at elevated temperatures and pressures.
U.S. Pat. No. 4,003,866, issued Jan. 18th, 1997, discloses a construction material comprising a plastic component containing a thermoplastic resin and a filler component. These components are mixed together under the application of heat. To improve the adhesion between the plastic material and the filler material, such as wood wastes, the particles of filler material before being mixed with the plastic are precoated under the application of heat tumbling with the polyethythlene or polypropylene wax having a molecular weight of from 1,000 to 10,000, a thermofluid high molecular weight polymer, or a silicate coating material.
Such prior art materials involving the various mixing, heating and coating steps are relatively expensive to produce and an adequate intimacy of bond between the plastic and filler is difficult to achieve.
SUMMARY OF THE INVENTION
The present invention is directed to providing very low cost and very durable products of composite material having superior qualities.
According to the invention such composite products are prepared by first subjecting a mixture of thermoplastic particles and particles of waste or filler material to a high intensity mixing operation to frictionally heat the particles to bring the thermoplastic particles to a molten state to wet and adhere to and coat or substantially coat or encapsulate the hot waste or filler particles bonding them together. The hot mixture is then subjected to a compression molding operation to compress the coated waste or filler particles together to force the molten thermoplastic material into the interstices and irregularities of the waste or filter particles to ensure their encapsulation while effecting a high strength bonding between the particles. On cooling and hardening of the thermoplastic material, there is created a dense. compacted composite product of the desired shape having a very high internal bonding.
The particles of thermoplastic material and waste or filler material used to produce the composite products of the invention may vary in size from a powder to particles of a size of about 1 centimeter. These particles may be prepared as necessary by shredding grinding or the like.
The high intensity mixing of the selected mixture of thermoplastic and waste or filler particulate material can be effectively carried out by introducing the mixture into a high intensity batch mixer in which rotating blades rotating at high tip speeds of the order of some 20 meters per second within a cylindrical chamber propel the particles into collision with each other and the mixer wall. This bombardment action not only effects intimate mixing of the particles but raises their temperature through a thermo-kinetic effect or internal frictional healing. As mixing continues, the thermoplastic particles first soften and then reach a molten state where they melt and wet and stick to the hot solid or unmelted particles so that the hot solid particles are coated and bonded together by the molten thermoplastic material.
The hot coated bonded waste or filler particles are then subject to a compacting pressure in a compression molding step wherein the molten thermoplastic material is forced into the fibers, pores, crevices, or irregularities of the waste or filler particles depending on their nature to lock these particles in the thermoplastic material ensuring their complete encapsulation and strengthening or enhancing the bonding between such entrapped or locked in particles.
The result of the compression molding step is the production of a product formed of densely compacted particulate material encapsulated and held together in an extremely strong bond by the thermoplastic material.
By preparing composite molded products as aforesaid, useful composite products, components or substructures can be produced using as little as 10% by weight of thermoplastic material, the rest being waste, recycled, or filler particulate material.
Further, according to the invention, such composite components or substructures may be incorporated into a composite product in which the component or substructure carries or is used to support a covering or cladding covering at least a portion of the surface thereof.
Because the thermoplastic material's function is to encapsulate and bind together the waste or filler particles, the invention enables the effective use of waste or recycled thermoplastic materials, such as reground low, medium, and high density polyethylene, polypropylene, polyethylene terephthalate (PET), nylon, PVC, ABS, and other ground up thermoplastic material as sources of thermoplastic material.
Particulate material which can be advantageously used as fillers are fibrous materials such as wood particles, i.e. sawdust, ground up wood pieces. ground cloth, paper, glass fibers, and reground thermosetting materials.
Still other examples of particulate material that are useful as fillers are waste materials such as fly ash, kiln dust, ground peanut shells, rice husks or corn husks. It will also be understood that many other particulate materials such as particles of rubber, metal, sand, concrete or the like may also be used.
Thus, it will be appreciated that the invention enables the production of highly useful products while at the same time achieving important environmental benefits by using up waste material which would otherwise have to be disposed of at an appropriate site.
It will be understood that various mixtures of particulate material can be used as desired or required. For instance, the inclusion of the fibrous particulate material provides good control of the expans
Kent Christopher T.
Royal Ecoproducts Limited
LandOfFree
Process of making products from recycled material containing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process of making products from recycled material containing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process of making products from recycled material containing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2443752