US-12623393-B2 - Wood plank and method of manufacturing the same

Abstract

A method of injecting a colorant into an extruded material and an artificial wood plank formed from said method. The method includes steps of extruding the material from an extruder to at least one die, shaping the material into a board via the at least one die, injecting the colorant into the material with at least one color injector in a pre-defined pattern, and forming a bubble in the material to impart a simulated woodgrain appearance into the material downstream of the at least one die.

Inventors

• Daniel Mark SCHLABACH

Assignees

• Green Fox Plastics, LLC

Dates

Publication Date

20260512

Application Date

20240111

Claims (18)

1. 1 . A method of injecting a colorant into an extruded material, comprising: extruding the material from an extruder to at least one die; shaping the material into a board via the at least one die; injecting the colorant into the material with at least one color injector in a pre-defined pattern, injecting the colorant into the material via the at least one color injector while the material passes through at least one of an injection block or a feed throat, the at least one color injector includes a first color injector and a second color injector, the first color injector being used to deliver a first colorant at a first injection depth relative to at least one of the injection block or the feed throat, the second color injector being used to deliver a second colorant at a second injection depth relative to at least one of the injection block or the feed throat, the first colorant being a different material than the second colorant, the first injection depth being different than the second injection depth; and forming a bubble in the material to impart a simulated woodgrain appearance into the material downstream of the at least one die.
2. 2 . The method of claim 1 , further comprising: delivering the colorant to the at least one color injector via a continuous feed; and transferring the colorant from the at least one color injector into the material via a nozzle of the at least one color injector.
3. 3 . The method of claim 2 , wherein the step of injecting the colorant into the material further comprises: directing the material through the injection block downstream of the at least one die; and injecting the colorant into the material via the at least one color injector while the material passes through the injection block.
4. 4 . The method of claim 3 , further comprising: adjusting the at least one color injector to a chosen injection depth relative to the injection block; wherein the colorant is injected into the material at the chosen injection depth.
5. 5 . The method of claim 4 , further comprising: adjusting at least another color injector to another chosen injection depth relative to the injection block; wherein the colorant is injected into the material at the another chosen injection depth that is different than the chosen injection depth of the colorant.
6. 6 . The method of claim 3 , wherein the step of shaping the material into the board further comprises: shaping the material into the board via the at least one die and the injector block.
7. 7 . The method of claim 3 , further comprising: directing the material into an extrusion gap defined between the injection block and a calibrator; forming the bubble of the material in the extrusion gap; and directing the material into the calibrator downstream of the injection block and the extrusion gap.
8. 8 . The method of claim 2 , wherein the step of extruding the material from the extruder to the at least one die further comprises: directing the material from an exit of the extruder to the at least one die via the feed throat operably connected therebetween.
9. 9 . The method of claim 8 , wherein the step of injecting the colorant into the material further comprises: injecting the colorant into the material via the at least one color injector while the material passes through the feed throat.
10. 10 . The method of claim 9 , further comprising: adjusting the at least one color injector to a chosen injection depth relative to the feed throat; wherein the colorant is injected into the material at the chosen injection depth.
11. 11 . The method of claim 10 , further comprising: adjusting at least another color injector to another chosen injection depth relative to the feed throat; wherein the colorant is injected into the material at the another chosen injection depth that is different than the chosen injection depth of the colorant.
12. 12 . The method of claim 8 , further comprising: directing the material into an extrusion gap defined between the at least one die and a calibrator; forming the bubble of the material in the extrusion gap; and directing the material into the calibrator downstream of the at least one die and the extrusion gap.
13. 13 . The method of claim 1 , wherein the step of injecting the colorant into the material further comprises: injecting the first colorant into the material via the first color injector while the material passes through the feed throat; and injecting the second colorant into the material via the second color injector while the material passes through the injection block.
14. 14 . The method of claim 1 , further comprising: adjusting the first color injector to the first injection depth relative to the feed throat, wherein the first colorant is injected into the material at the first injection depth; and adjusting the second color injector to the second injection depth relative to the injection block.
15. 15 . The method of claim 1 , wherein the colorant is injected into the material in such a manner as to yield an accurate woodgrain coloration in an extruded plastic lumber product.
16. 16 . The method of claim 3 , further comprising adjusting a chosen injection depth of the at least one color injector relative to the injection block.
17. 17 . The method of claim 7 , wherein the bubble formed in the extrusion gap is configured to create at least one of patterns or designs in the material to thereby impart the simulated woodgrain appearance.
18. 18 . The method of claim 7 , wherein the extrusion gap is in a range of one-half inch to one inch wide.

Description

REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application Ser. No. 63/479,467, filed on Jan. 11, 2023; the disclosure of which is incorporated herein by reference. TECHNICAL FIELD The present disclosure relates generally to the field of extrusion molding, more particularly, in one example, methods and apparatus for extrusion molding of plastic lumber products. BACKGROUND ART Extrusion manufacturing, particularly plastic extrusion, is a high volume manufacturing process which can be used to create objects having a fixed cross sectional profile. Extrusion may be utilized with any material but is commonly utilized with polymers, plastics, and other composite materials to produce various goods. One plastics extrusion product that is increasing in popularity is that of plastic or composite lumber products, which may then be utilized in place of wood as a building material for any application including decking, flooring, paneling, furniture making, or any other application where wood may normally be utilized. Large scale extrusion processes, particularly those used to create plastic or composite lumber products, can use raw plastic stock, including recycled plastic material, to create a continuous or semi-continuous extrusion that may be formed to take the shape of a board, or other similar profile products. Commonly, these processes utilize raw plastic in the form of small beads called nurdles, which may be fed from a hopper into the extruder where the nurdles may be melted and driven through a die utilizing a screw or other similar device to push to molten plastic material into the die to form the shape of the end product. The die may have any shape or size and may include various profile and/or aesthetic components to impart a specific shape and/or profile to the end product. Where extrusion is utilized to create plastic lumber, the die may include features such as rounded corners or texture imparting components designed to give a more natural or wood-like feel to the end product. Alternatively, as desired, a texture, such as woodgrain texture, may be embossed or otherwise pressed into the extrusion product as the plastic cools. While this may provide an aesthetically pleasing look and feel, consumers tend to desire a more realistic looking product, including products having the appearance of woodgrain and woodgrain textures that are more natural and better approximate the look and feel of real wood, while providing the durability and uniform consistency of plastic or composite lumber products. Current processes to address the introduction of simulated woodgrain appearance into extruded plastic lumber include a process known as streaking, wherein colorants and/or colored pellets are introduced as concentrates at the beginning of the extrusion process. This may result in a homogenous mixture of the main polymer with the colorants producing streaks of concentrated color where the color concentrates are added. This produces a longitudinal streak effect that is typically limited to the surface of the board; however, this can impart an artificial look and is not typically uniform and does not reproduce the look and feel of a real woodgrain product as accurately as desired. Other solutions may include complex layering and mixing of coextruded colored layers that, while providing an aesthetically pleasing appearance, increase the cost and difficulty of the manufacturing process. Additionally, embossing textures and patterns into the extruded product, as mentioned above, can create a textured look and feel but does not address the coloration and/or woodgrain appearance that is currently considered desirable. SUMMARY OF THE INVENTION The present disclosure addresses these and other issues by providing a color injection system that may inject streaks of color concentrate into the extrusion process at non-random and controlled intervals and at various depths to create a more visually appealing and accurate simulation of woodgrain coloration into an extruded plastic lumber product while minimizing the need for coextruded layers and/or extrusion mixing in the manufacturing process. In another aspect, an exemplary embodiment of the present disclosure may provide an extrusion color injection system comprising: an extruder; at least one die operable to shape material exiting the extruder; and at least one color injector operable to inject a colorant into the material exiting the extruder in a pre-defined pattern and amount to impart a simulated woodgrain appearance into the material. In yet another aspect, an exemplary embodiment of the present disclosure may provide a method of injecting a colorant into an extruded material comprising: extruding material from an extruder to at least one die; shaping the material into a board via the at least one die; and injecting a colorant into the material with at least one color injector in a pre-defined pattern and amount to impart a simulated