Golf club head comprising microscopic bubble material
A golf club head with at least one cavity including a weight that is co-molded with a fill material comprising a polymer and a plurality of microscopic bubbles, and methods of manufacturing such golf club heads, are disclosed herein. The plurality of microscopic bubbles constitutes at 5-70% of the volume of the fill material, and more preferably approximately 20-30% of the volume of the fill material. The polymer material preferably is a polyurethane having a Poisson's ratio of 0.40-0.50. The weight is preferably composed of a metal alloy with a density greater than 4 g/cc, such as steel or tungsten alloy.
1. A golf club head comprising:
a body comprising a striking face, sole portion, top portion, rear portion, and cavity;
a metal weight; and
a fill material comprising a first material and a plurality of microscopic bubbles composed of a second material,
wherein the second material is different from the first material,
wherein the metal weight is disposed within the cavity,
wherein the fill material at least partially envelops the metal weight and at least partially fills the cavity, and
wherein the plurality of microscopic bubbles constitutes 5% to 70% of a volume of the fill material.
2. The golf club head of claim 1 , wherein the first material is selected from the group consisting of polyurethane and silicone.
3. The golf club head of claim 1 , wherein the second material is selected from the group consisting of glass, ceramic, and plastic.
4. The golf club head of claim 3 , wherein each of the plurality of microscopic bubbles has a diameter of approximately 18-50 microns.
5. The golf club head of claim 1 , wherein the plurality of microscopic bubbles constitutes at least 20% of the volume of the fill material.
6. The golf club head of claim 5 , wherein the plurality of microscopic bubbles constitutes 25-30% of the volume of the fill material.
7. The golf club head of claim 1 , wherein the polymer material has a Poisson's ratio of 0.00-0.50.
8. The golf club head of claim 7 , wherein the polymer material has a Poisson's ratio of 0.40-0.50.
9. The golf club head of claim 1 , wherein the metal weight is composed of tungsten alloy.
10. The golf club head of claim 1 , wherein the fill material completely envelops the metal weight.
11. The golf club head of claim 1 , wherein a combination of the metal weight and the fill material completely fills the cavity.
12. The golf club head of claim 1 , wherein the golf club head is an iron-type golf club head.
13. A method comprising the steps of:
providing a golf club head comprising a body having a cavity;
providing a metal weight;
providing a fill material comprising a polymer material and a plurality of microscopic bubbles composed of a low-density material;
injection-molding the fill material onto the metal weight to create a co-molded weight; and
inserting the co-molded weight into the cavity.
14. The method of claim 13 , wherein the plurality of microscopic bubbles constitutes approximately 25-30% of the volume of the fill material.
15. The method of claim 13 , wherein the polymer material is selected from the group consisting of polyurethane and silicone, and wherein the low-density material is composed of a material selected from the group consisting of glass, ceramic, and plastic.
16. The method of claim 15 , wherein the golf club head is an iron-type golf club head comprising a body having a striking face, a sole portion, a top portion, and a rear portion, wherein the at least one cavity is disposed between the striking face and the rear portion, and wherein a combination of the metal weight and the fill material completely fills the at least one cavity.
17. A method comprising the steps of:
providing a golf club head comprising a body having a cavity;
providing a metal weight;
providing a fill material comprising a polymer material and a plurality of microscopic bubbles composed of a low-density material;
inserting the metal weight into the cavity; and
injection-molding the fill material into the cavity and around at least a portion of the metal weight.
18. The method of claim 17 , wherein the polymer material is selected from the group consisting of polyurethane and silicone, and wherein the low-density material is composed of a material selected from the group consisting of glass, ceramic, and plastic.
19. The method of claim 18 , wherein the plurality of microscopic bubbles constitutes 25-30% of the volume of the fill material, and wherein each of the plurality of microscopic bubbles has a diameter of approximately 18-50 microns.
20. The golf club head of claim 17 , wherein the metal weight is composed of a metal alloy having a density of greater than 4 g/cc.