Golf club head

1. A golf club head comprising:

a heel portion, a toe portion, a crown, a sole, and a face having a non-metallic striking surface for striking a golf ball;

the face having a center of the striking surface defining the origin of a coordinate system including an x-axis, extending tangent to the center of the striking surface and generally parallel to a flat ground surface when the golf club head is in an address position on the flat ground surface, a y-axis, extending substantially perpendicular to the x-axis and generally parallel to the flat ground surface when the golf club head is in the address position on the flat ground surface, and a z-axis, extending substantially perpendicular to the x-axis and to the y-axis, wherein a negative direction of the x-axis points toward the heel portion and a positive direction of the x-axis points toward the toe portion;

the face having a first off-center location on the face located in a heel direction away from the center of the striking surface at −40 mm along the x-axis and a second off-center location on the face located in a toe direction away from the center of the striking surface at 40 mm along the x-axis; and

wherein a characteristic time at 10 mm increment locations on the face along the x-axis between the first off-center location and the second off-center location deviates from the characteristic time at the center of the striking surface by no more than 20%; and

wherein the golf club head has:

a moment of inertia about a center-of-gravity (CG) x-axis, passing through a CG of the golf club head and parallel to the x-axis, is between about 300 kg·mm 2 and about 500 kg·mm 2 ;

a moment of inertia about a CG z-axis, passing through the CG of the golf club head and parallel to the z-axis, is between about 450 kg·mm 2 and about 650 kg·mm 2 ; and

a depth of at least 111.76 mm, a CG y-axis coordinate of 30-50 mm, and a CG z-axis coordinate of between about −10 mm and about 5 mm; and

a non-metal face plate that contacts the ball at impact, wherein the face plate defines the striking surface and comprises a lay-up of multiple, composite prepreg plies, wherein at least a portion of the plies comprises a plurality of elongated prepreg strips arranged in a criss-cross pattern defining an overlapping region at the center of the striking surface where the strips overlap each other, the lay-up having a first thickness at a location spaced from the overlapping region and a second thickness at the overlapping region, the second thickness being greater than the first thickness.

2. The golf club head of claim 1 , wherein a second off-center characteristic time at the second off-center location is at least 200 μs, and the non-metal face plate includes a polymer cover layer comprising a plurality of surface features to provide a mean roughness of 2.5-5 μm, wherein the polymer cover layer defines the striking surface.

3. The golf club head of claim 2 , wherein a first off-center characteristic time at the first off-center location is at least 200 μs, and the polymer cover layer has a cover layer thickness of 0.1-3.0 mm.

4. The golf club head of claim 3 , wherein the second off-center characteristic time is at least 210 μs, and the polymer cover layer is transparent.

5. The golf club head of claim 4 , wherein the first off-center characteristic time is at least 210 μs.

6. The golf club head of claim 5 , wherein the non-metal face plate includes a plurality of grooves formed in the polymer cover layer.

7. The golf club head of claim 6 , wherein at least a portion of the plurality of surface features have a peak to trough height of between 20 μm and 30 μm.

8. The golf club head of claim 6 , wherein adjacent surface features are separated by no more than 0.6 mm.

9. The golf club head of claim 6 , further comprising a weight port and a weight retained by the weight port, wherein the weight port is located at a back portion of the golf club head, the back portion being on an opposite side of the golf club head as the face.

10. The golf club head of claim 2 , wherein the non-metal face plate is adhesively attached to the golf club head.

11. The golf club head of claim 10 , wherein the non-metal face plate has an insert height dimension of between 50 mm and 127 mm.

12. The golf club head of claim 11 , wherein the non-metal face plate has an insert width dimension of between 100 mm and 127 mm.

13. The golf club head of claim 12 , wherein the golf club head has a height of 63.5-71 mm and a width of 119.38-127 mm.

14. The golf club head of claim 10 , wherein the non-metal face plate has an insert perimeter and the golf club head comprises a hinge region supporting the insert perimeter, and a portion of the hinge region is formed of aluminum alloy.

15. The golf club head of claim 14 , wherein a portion of the hinge region is formed of steel alloy.

16. The golf club head of claim 2 , wherein a first off-center characteristic time at the first off-center location is at least 200 μs.

17. The golf club head of claim 16 , wherein the second off-center characteristic time is at least 210 μs, and the prepreg strips form at least one cluster of prepreg strips.

18. The golf club head of claim 17 , wherein the first off-center characteristic time is at least 210 μs, and at least one cluster is located in between adjacent prepreg panels.

19. The golf club head of claim 17 , wherein the first off-center characteristic time is at least 210 μs.

20. The golf club head of claim 17 , wherein the first off-center characteristic time is at least 210 μs, and at least one of the plurality of prepreg strips extends continuously across the non-metal face plate.

21. The golf club head of claim 16 , wherein the second off-center characteristic time is at least 210 μs, and the non-metal face plate has a thickness at the center of the striking surface that is greater than a thickness at a peripheral edge of the striking surface, wherein the thickness at the center of the striking surface is between 4 mm and 9 mm and the thickness at the peripheral edge of the striking surface is between 3 mm and 6 mm.

22. The golf club head of claim 16 , wherein the second off-center characteristic time is at least 210 μs, and the polymer cover layer has a plurality of grooves, and at least a portion the polymer cover layer has a cover layer thickness of 0.1-3.0 mm.

23. The golf club head of claim 22 , wherein the polymer cover layer is transparent.

24. The golf club head of claim 23 , wherein at least a portion of the plurality of surface features have a peak to trough height of between 20 μm and 30 μm.

25. A golf club head comprising:

a heel portion, a toe portion, a crown, a sole, and a face having a non-metallic striking surface for striking a golf ball;

the face having:

a center of the striking surface defining the origin of a coordinate system including an x-axis, extending tangent to the center of the striking surface and generally parallel to a flat ground surface when the golf club head is in an address position on the flat ground surface, a y-axis, extending substantially perpendicular to the x-axis and generally parallel to the flat ground surface when the golf club head is in the address position on the flat ground surface, and a z-axis, extending substantially perpendicular to the x-axis and to the y-axis, wherein a negative direction of the x-axis points toward the heel portion and a positive direction of the x-axis points toward the toe portion;

a first off-center location on the face located in a heel direction away from the center of the striking surface at −40 mm along the x-axis and a second off-center location on the face located in a toe direction away from the center of the striking surface at 40 mm along the x-axis;

a plurality of surface features to provide a mean roughness of 2.5-5 μm;

a non-metallic substrate having a substrate front surface;

a transparent polymer cover layer in contact with the substrate front surface and a portion having a cover layer thickness of 0.1-3.0 mm; and

a plurality of grooves formed in the polymer cover layer;

wherein a characteristic time at 10 mm increment locations on the face along the x-axis between the first off-center location and the second off-center location deviates from the characteristic time at the center of the striking surface by no more than 20%; and

wherein the golf club head has:

a moment of inertia about a center-of-gravity (CG) x-axis, passing through a CG of the golf club head and parallel to the x-axis, is between about 300 kg·mm 2 and about 500 kg·mm 2 ;

a moment of inertia about a CG z-axis, passing through the CG of the golf club head and parallel to the z-axis, is between about 450 kg·mm 2 and about 650 kg·mm 2 ; and

a depth of at least 111.76 mm, a CG y-axis coordinate of 30-50 mm, and a CG z-axis coordinate of between about −10 mm and about 5 mm; and

a non-metal face plate that contacts the ball at impact, wherein the face plate defines the striking surface and comprises a lay-up of multiple, composite prepreg plies, wherein at least a portion of the plies comprises a plurality of elongated prepreg strips arranged in a criss-cross pattern defining an overlapping region at the center of the striking surface where the strips overlap each other, the lay-up having a first thickness at a location spaced from the overlapping region and a second thickness at the overlapping region, the second thickness being greater than the first thickness.

26. A golf club head comprising:

a heel portion, a toe portion, a crown, a sole, and a face having a non-metallic striking surface for striking a golf ball;

the face having:

a center of the striking surface defining the origin of a coordinate system including an x-axis, extending tangent to the center of the striking surface and generally parallel to a flat ground surface when the golf club head is in an address position on the flat ground surface, a y-axis, extending substantially perpendicular to the x-axis and generally parallel to the flat ground surface when the golf club head is in the address position on the flat ground surface, and a z-axis, extending substantially perpendicular to the x-axis and to the y-axis, wherein a negative direction of the x-axis points toward the heel portion and a positive direction of the x-axis points toward the toe portion;

a first off-center location on the face located in a heel direction away from the center of the striking surface at −40 mm along the x-axis and a second off-center location on the face located in a toe direction away from the center of the striking surface at 40 mm along the x-axis;

a plurality of composite prepreg plies includes a plurality of prepreg panels and at least one cluster comprising a plurality of prepreg strips; and

a mean roughness of 2.5-5 μm;

wherein a characteristic time at 10 mm increment locations on the face along the x-axis between the first off-center location and the second off-center location deviates from the characteristic time at the center of the striking surface by no more than 20%; and

wherein the golf club head has:

a moment of inertia about a center-of-gravity (CG) x-axis, passing through a CG of the golf club head and parallel to the x-axis, is between about 300 kg·mm 2 and about 500 kg·mm 2 ;

a moment of inertia about a CG z-axis, passing through the CG of the golf club head and parallel to the z-axis, is between about 450 kg·mm 2 and about 650 kg·mm 2 ; and

a depth of at least 111.76 mm, a CG y-axis coordinate of 30-50 mm, and a CG z-axis coordinate of between about −10 mm and about 5 mm; and

a non-metal face plate that contacts the ball at impact, wherein the face plate defines the striking surface and comprises a lay-up of multiple, composite prepreg plies, wherein at least a portion of the plies comprises a plurality of elongated prepreg strips arranged in a criss-cross pattern defining an overlapping region at the center of the striking surface where the strips overlap each other, the lay-up having a first thickness at a location spaced from the overlapping region and a second thickness at the overlapping region, the second thickness being greater than the first thickness, thereby adjusting the characteristic time at various locations along the x-axis.