Dual color blow molding process
An example extrusion blow molding (EBM) method includes extruding first and second colors of plastic to form a parison that includes an inner layer of the first color of plastic, and an outer layer of the second color of plastic. The parison is placed in a mold, the mold is closed, and the parison is inflated to create a blow molded structure. A portion of an interior of the blow molded structure is formed of the first color of plastic, and a portion of an exterior of the blow molded structure is formed of a blend of the first color of plastic and the second color of plastic.
1. A method, comprising:
extruding plastic of a first color and plastic of a second color to form a parison comprising melted plastic, wherein the parison includes an inner layer comprising the plastic of the first color, and the parison also includes an outer layer comprising the plastic of the second color, and wherein during and/or after the extruding, the plastic of the first color blends together with the plastic of the second color so that a portion of the parison comprises a blend of the plastic of the first color and the plastic of the second color;
placing the parison in a mold; and
inflating the parison to create a portion of a watercraft.
2. The method as recited in claim 1 , wherein a portion of the outer layer of the parison comprises the blend.
3. The method as recited in claim 1 , wherein one of the plastic of the first color and the plastic of the second color includes regrind.
4. The method as recited in claim 1 , wherein the plastic of the first color and the plastic of the second color are not blended with each other until after exiting a diverter.
5. The method as recited in claim 1 , wherein a portion of an exterior of the portion of the watercraft includes one or more randomly distributed irregularities in one or more of color, color gradient, tone, color depth, and color distribution.
6. The method as recited in in claim 5 , wherein one or more of the irregularities is produced by one or more of: pulsations imposed by an accumulator head as the plastic of the first color and the plastic of the second color exit the accumulator head to form the parison; creep, in the parison, of the plastic of the first color and the plastic of the second color, once the parison has been formed; a temperature differential in the parison; and, differential stretching of one of the inner layer and the outer layer relative to the other of the inner layer and the outer layer.
7. The method as recited in claim 1 , wherein a portion of an interior of the portion of the watercraft is defined by the inner layer of the parison, and a portion of an exterior of the portion of the watercraft is defined by the outer layer of the parison.
8. The method as recited in claim 1 , wherein a feed rate of the plastic of the first color to an extrusion die is different from a feed rate of the plastic of the second color to the extrusion die.
9. The method as recited in claim 1 , wherein a feed rate of the plastic of the first color to an extrusion die is the same as a feed rate of the plastic of the second color to the extrusion die.
10. The method as recited in claim 1 , wherein the extruding is performed by an extrusion machine that includes an accumulator head and a double heart diverter.
11. The method as recited in claim 1 , wherein the portion of the watercraft is created without the use of a preform or an overmold.
12. The method as recited in claim 1 , wherein a portion of the blend is created during the extruding.
13. The method as recited in claim 1 , wherein the portion of the watercraft is created without the use of injection molding, stretch blow molding, rotomolding, or twin sheet molding.
14. The method as recited in claim 1 , wherein the portion of the watercraft comprises a portion of a kayak, or a portion of a paddleboard.
15. The method as recited in claim 1 , wherein the portion of the watercraft comprises a hull.
16. A method, comprising:
extruding a plastic of a first color and a plastic of a second color to form a parison comprising melted plastic, wherein during and/or after the extruding, the plastic of the first color blends together with the plastic of the second color so that a portion of the parison comprises a blend of the plastic of the first color and the plastic of the second color;
placing the parison in a mold; and
inflating the parison to create a portion of a watercraft.
17. The method as recited in claim 16 , wherein a portion of an exterior of the portion of the watercraft comprises the blend.
18. The method as recited in claim 16 , wherein one of the plastic of the first color and the plastic of the second color includes regrind.
19. The method as recited in claim 16 , wherein the plastic of the first color and the plastic of the second color are not blended with each other until after exiting a diverter.
20. The method as recited in claim 16 , wherein a portion of an exterior of the portion of the watercraft includes one or more randomly distributed irregularities in one or more of color, color gradient, tone, color depth, and color distribution.
21. The method as recited in claim 16 , wherein a feed rate of the plastic of the first color to an extrusion die is different from a feed rate of the plastic of the second color to the extrusion die.
22. The method as recited in claim 16 , wherein a feed rate of the plastic of the first color to an extrusion die is the same as a feed rate of the plastic of the second color to the extrusion die.
23. The method as recited in claim 16 , wherein the extruding is performed by an extrusion machine that includes an accumulator head and a double heart diverter.
24. The method as recited in claim 16 , wherein the plastic of the first color and the plastic of the second color are the same physically and chemically identical polymer.
25. The method as recited in claim 16 , wherein the portion of the watercraft is created without the use of a preform or an overmold.
26. The method as recited in claim 16 , wherein a portion of the blend is created during the extruding.
27. The method as recited in claim 16 , wherein the portion of the watercraft is created without the use of injection molding, stretch blow molding, rotomolding, or twin sheet molding.
28. The method as recited in claim 16 , wherein the blend is formed by bleed through of one of the plastic of the first color and the plastic of the second color into the other of the plastic of the first color and the plastic of the second color.
29. The method as recited in claim 16 , wherein the portion of the watercraft comprises a portion of a kayak, or a portion of a paddleboard.
30. The method as recited in claim 16 , wherein the portion of the watercraft comprises a hull.
31. The method as recited in claim 16 , wherein the portion of the watercraft comprises a kayak having a unitary, one piece, construction.
32. The method as recited in claim 16 , wherein the portion of the watercraft comprises a paddleboard having a unitary, one piece, construction.
33. The method as recited in claim 16 , wherein the extruding is performed in such a way that an interior of the portion of the watercraft is the first color, and an exterior of the portion of the watercraft is a combination of the first color and the second color.
34. The method as recited in claim 1 , wherein the portion of the watercraft comprises a kayak having a unified, single piece, construction.
35. The method as recited in claim 1 , wherein the portion of the watercraft comprises a paddleboard having a unified, single piece, construction.
36. The method as recited in claim 1 , wherein the extruding is performed in such a way that an interior of the portion of the watercraft is the first color, and an exterior of the portion of the watercraft is a combination of the first color and the second color.