US20080172981A1

US20080172981A1 - Non-organic composite lumber

Info

Publication number: US20080172981A1
Application number: US11/625,462
Authority: US
Inventors: Donald Iverson
Original assignee: Crawford Industries LLC
Current assignee: Crawford Industries LLC
Priority date: 2007-01-22
Filing date: 2007-01-22
Publication date: 2008-07-24
Also published as: CA2582817A1; MX2007003721A

Abstract

A non-organic composite lumber including primarily plastic and minerals for use as decking among many applications.

Description

BACKGROUND

The present invention relates to composite lumber manufactured from non-organic materials.
Composite lumber made from both natural and synthetic materials is known in the art. When natural organics such as wood fillers and the like are utilized, this composite lumber material is susceptible to color fading, rotting and molding. When such composite lumber material absorbs moisture, it has the potential to behave like wood leading to serious problems like cracking, fading, rotting, warping and loss of strength. Most synthetic composite lumber materials fade dramatically over the first few years and some start to lose their original color within sixty days due to their organic materials.

SUMMARY

In one embodiment, the invention includes a composite lumber material comprising at least one plastic in an amount by weight less than 90% and at least one mineral in an amount by weight greater than 10%. In another embodiment, the invention includes a composite lumber material comprising at least one plastic in an amount by weight in the range of 50-60% and at least one mineral in an amount by weight in the range of 40-50%. In another embodiment, the invention includes a composite lumber material comprising HDPE in an amount by weight in the range of 50-60% and at least one mineral in an amount by weight in the range of 40-50%, said mineral including at least one of talc, calcium carbonate and wollastonite. In another embodiment, the invention includes a composite lumber material comprising HDPE in an amount by weight in the range of 50-60%, at least one mineral in an amount by weight in the range of 40-50%, a coupling agent, a blowing agent and a pigment.
Other aspects of the invention will become apparent by consideration of the accompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a piece of composite lumber of the present invention.

FIG. 2 is an end view of the composite lumber.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
Turning to FIGS. 1 and 2, the composite lumber 10 of the present invention is shown. The composite lumber is shown in the form it exits the manufacturing process. However, it should be noted that other forms can be utilized and the manufactured product can be cut into various shapes as need for any given application.
The composite lumber includes no organic components. By weight, the composite lumber is primarily comprised of at least one plastic and at least one mineral. Other components can include a blowing agent, a coupling agent and pigments. It should be noted that other components and additives can be added as desired.
Preferably, the plastic component is a polymeric compound such as a high density polyethylene (HDPE) and, by weight, makes up less than 90% of the composite lumber, and more preferably makes up in the range of 50-60% by weight of the composite lumber. The source of the plastic can either be virgin or recycled as are available from many commercial sources. It should be noted that other types of plastic or more than one plastic can also be utilized.
Preferably, the mineral component makes up more than 10% by weight of the composite lumber, and more preferably makes up in the range of 40-50% by weight of the composite lumber. For example, at least one of the following minerals can be utilized in the instant invention: talc, calcium carbonate and wollastonite. All three of these minerals can be used and in the following ranges: 0-5% wollastonite, 0-35% calcium carbonate and the remainder talc. The mineral component of the composite lumber enhances the manufacturing process due to increased flowability and addition to the strength of the composite lumber. It should be noted that minerals other than the three examples set forth above can also be utilized in the present invention. The minerals are available from many commercial sources.
A blowing agent such as nitrogen is preferably added to lighten the composite lumber. For example, the end weight of the composite lumber is less than or equal to about 2.4 lb/ft for a 5¼ inch board. Preferably, the blowing agent makes up 0-3% by weight of the composite lumber. The blowing agent is available from many commercial sources.
A coupling agent is preferably added to the composite lumber. An example of such a coupling agent is Epolene G-2608 polymer available from the Eastman Chemical Company. The coupling agent aids in thoroughly mixing the components prior to manufacture of a finished product. Preferably, the coupling agent makes up 0-3% by weight of the composite lumber. The coupling agent is available from many commercial sources.
The composite lumber can include pigments as are well know in the art and available from many commercial sources. The amount of pigment added can vary as is desired for a given finished product.
The composite lumber can be manufactured using many traditional processes such as extrusion and blow molding. Preferably, the composite lumber is extruded as is known in the art. Prior to extrusion, the plastic and mineral components are mixed and pelletized. The resulting pellets are dried to remove moisture to approximately 0.02% moisture. The pellets are then mixed with the blowing agent, the coupling agent and the pigment and then fed to the extruder. The dimensions of the composite lumber exiting the extruder can be changed as desired. Further, any pattern 12 can be included on the surface of the composite lumber as is shown in FIG. 1. The pattern can be incorporated such as through the use of a die during the manufacturing process.
The composite lumber is entirely non-organic. As such, it cannot absorb moisture and is 100% moisture proof. As such, its color retention is superior to organic based composite lumber materials. The composite lumber of the present invention will not rot, absorb moisture, mold nor become termite infested.
As an example, one formulation of the composite lumber includes the following components:
55% plastic (HDPE)
40% minerals (of which 100% is talc)
3% additives (of which 2.0% is a coupling agent and 1.0% is a bonding agent)
2% pigment.
This formulation of a composite lumber of the present invention meets or exceeds all ICC test requirements. Technical data on this specific formulation is as follows.

TABLE 1

	TEST		TEST
PROPERTIES	METHOD	UNIT	RESULT

Modulus of Elasticity 72° F.	ASTM D6109	PSI	245,419
Modulus of Elasticity −20° F.	ASTM D6109	PSI	584,860
Compression Strength 72° F.	ASTM D6108	PSI	3,000
Compression Strength −30° F.	ASTM D6108	PSI	4,000
Modulus of Rupture	ASTM D6109	PSI	3,327
Specific Gravity	ASTM D6111-97		1.13
Flexural Strength	ASTM D790	PSI	3,500.00
Falling Dart Impact Strength	ASTM D5420	Lbs	350.00
72° F.
Falling Dart Impact Strength	ASTM D5420	Lbs	550.00
−30° F.
Nail Retention	ASTM D6117	Lbs	350.00
Screw Retention	ASTM D6117	Lbs	600.00
Tensile Strength	ASTM D638	PSI	2,100.00
Coefficient of Linear Thermo	ASTM D6341		3.5 × 10−5
Expansion & Contraction
Shear Test Strength	ASTM D6435	PSI	1,200.00
Water Absorption	ASTM D1037		0.05%
Flame Spread Index	ASTM E84		Class 2(B)
Smoke Index	ASTM		750

The uses of the composite lumber of the present invention are numerous and include, for example, as decking, patios, piers, docks, fencing, stair cases, spindles, railings, trailers, picnic tables, pool decks and many other applications in which a traditional wood product can be used.
Various features and advantages of the invention are set forth in the following claims.

Claims

1. A composite lumber material comprising:

at least one plastic in an amount by weight less than 90%; and

at least one mineral in an amount by weight in the range of 40-50%,

with the proviso that the composite lumber material does not include organic components.

2. The composite lumber of claim 1 where the plastic includes HDPE.

3. The composite lumber of claim 1 wherein the plastic is in an amount in the range of 50-60% by weight.

4. The composite lumber of claim 1 wherein the mineral includes at least one of talc, calcium carbonate and wollastonite.

5. The composite lumber of claim 1 wherein the mineral includes talc.

6. (canceled)

7. The composite lumber of claim 1 and further including a blowing agent.

8. The composite lumber of claim 1 and further including a coupling agent.

9. (canceled)

10. The composite lumber of claim 1 wherein the plastic is selected from at least one of virgin and recycled.

11. The composite lumber of claim 1 and further including a pigment.

12. A composite lumber material comprising:

at least one plastic in an amount by weight in the range of 50-60%; and

at least one mineral in an amount by weight in the range of 40-50%,

13. The composite lumber of claim 12 wherein the mineral includes at least one of talc, calcium carbonate and wollastonite.

14. The composite lumber of claim 12 wherein the mineral includes talc.

15. The composite lumber of claim 12 and further including a blowing agent and a coupling agent.

16. (canceled)

17. A composite lumber material comprising:

HDPE in an amount by weight in the range of 50-60%; and

at least one mineral in an amount by weight in the range of 40-50%, said mineral including at least one of talc, calcium carbonate and wollastonite,

18. The composite lumber of claim 17 and further including a blowing agent.

19. The composite lumber of claim 17 and further including a coupling agent.

20. (canceled)

21. The composite lumber of claim 17 wherein the plastic is selected from at least one of virgin and recycled.

22. The composite lumber of claim 17 and further including a pigment.

23. A composite lumber material comprising:

HDPE in an amount by weight in the range of 50-60%;

at least one mineral in an amount by weight in the range of 40-50%;

a coupling agent;

a blowing agent; and

a pigments,