초록 ▼

A method for forming a surfboard is provided. The method comprises adding a polyethylene mixture into a mold having one or more ventilation holes located therein. The polyethylene mixture comprises a blend of a polyethylene material and a foaming agent. The polyethylene material is in a form compris

A method for forming a surfboard is provided. The method comprises adding a polyethylene mixture into a mold having one or more ventilation holes located therein. The polyethylene mixture comprises a blend of a polyethylene material and a foaming agent. The polyethylene material is in a form comprising at least one of a powder form, a pellet form and mixtures thereof. In addition, the method comprises heating the polyethylene mixture in the mold while rotating the mold for a pre-determined period of time and at a predetermined temperature. Further, the method also comprises cooling the mold for a predetermined amount of time, and wherein either a main body of a surfboard or an entire surfboard is then formed.

대표청구항 ▼

What is claimed is: 1. A method of forming a surfboard using a two-shot rotational molding process comprising: adding a first polyethylene material into a mold, said mold having one or more ventilation holes located therein; heating the first polyethylene material in the mold while rotating the mol

What is claimed is: 1. A method of forming a surfboard using a two-shot rotational molding process comprising: adding a first polyethylene material into a mold, said mold having one or more ventilation holes located therein; heating the first polyethylene material in the mold while rotating the mold for a pre-determined period of time and at a predetermined temperature to form a skin, said first polyethylene material being in a form comprising at least a powder form, wherein the first polyethylene material forms the skin as substantially solid without any substantial air voids; adding a polyethylene mixture into the mold, wherein the polyethylene mixture comprises a blend of a second polyethylene material and a foaming agent, said second polyethylene material being in a form comprising at least a pellet form and/or a micropellet form, wherein the second polyethylene material is the same as the first polyethylene material; and heating the polyethylene mixture inside the mold while rotating the mold for a pre-determined period of time and at a predetermined temperature to form a foam core; and cooling said mold for a predetermined amount of time wherein either a main body of a surfboard or an entire surfboard is then formed, and wherein the foam core transitions from the skin as a single unit with the skin and made of the same polyethylene material. 2. The method of claim 1, wherein said mold containing said first polyethylene material is rotated about multiple axes while being heated. 3. The method of claim 2, wherein the mold containing said first polyethylene material is heated to a temperature in a range of about 525° F. to about 625° F. on the exterior of the mold to produce a temperature of in a range of about 380° F. to about 450° F. on the inside of the mold, and wherein the mold containing the first polyethylene material is heated and rotated for a period of at least about 20 minutes. 4. The method of claim 1, wherein said mold containing said polyethylene mixture is rotated about multiple axes while being heated. 5. The method of claim 4, wherein the mold containing said combination of said first polyethylene material and said polyethylene mixture is heated to a temperature in a range of about 525° F. to about 625° F. on the exterior of the mold to produce a temperature in a range of about 380° F. to about 450° F. on the inside of the mold, and wherein the mold containing the combination of said first polyethylene material and said polyethylene mixture is heated and rotated for a period of at least about 20 minutes and then cooled while stationary for at least about 20 minutes. 6. The method of claim 1, wherein said first and second polyethylene materials are each an ultra-violet (UV) resistant polyethylene material, said first and second UV resistant polyethylene material include a coloring agent for providing color. 7. The method of claim 1, wherein said mold comprises a general surfboard shape forming an interior cavity, said mold is comprised of a heat conductive material. 8. The method of claim 1, wherein said mold is heated while being rotated using a rotary molding machine having a heating apparatus. 9. The method of claim 1, wherein after said cooling of said mold for said predetermined amount of time then said entire surfboard is formed within said mold, said entire surfboard comprising a main body with one or more fins formed integrally with a portion of the main body of the surfboard. 10. The method of claim 1, further comprising removing said main body from said mold after said main body is formed by said cooling of said mold for said predetermined amount of time, and then removably attaching one or more fins to a portion of the main body to form said entire surfboard outside of said mold. 11. The method of claim 1 further comprising locating at least one surfboard strengthening stringer in the mold, wherein heating the polyethylene mixture forms the foam core at least partially around the stringer. 12. The method of claim 1 wherein the skin and the inner core are integrally formed as a one-piece member made of the same material as two sections with the inner core having air voids and the skin being substantially solid. 13. The method of claim 1 further comprising connecting at least one surfboard strengthening stringer to the surfboard after cooling. 14. A method of forming a surfboard using a two-shot rotational molding process comprising: adding a first polyethylene material into a mold, said mold having one or more ventilation holes located therein; heating the first polyethylene material in the mold while rotating the mold for a pre-determined period of time and at a predetermined temperature to form a skin, said first polyethylene material being in a form comprising at least a powder form, wherein the first polyethylene material forms the skin as a solid outer section of the surfboard; adding a polyethylene mixture into the mold, wherein the polyethylene mixture comprises a blend of a second polyethylene material and a foaming agent, wherein the second polyethylene material is the same as the first polyethylene material, said second polyethylene material being in a form comprising at least a pellet form or a micropellet form; heating the polyethylene mixture inside the mold while rotating the mold for a pre-determined period of time and at a predetermined temperature to form a foam core; cooling said mold for a predetermined amount of time wherein a main body of a surfboard is formed, wherein the foam core transitions from the skin as a single unit with the skin and made of the same polyethylene material; and attaching one or more fine directly to the outer section of the main body to form an entire surfboard after said main body has been formed within said mold by said cooling of said mold for said predetermined amount of time.