Dual Core Golf Ball Having A Shallow "Positive Hardness Gradient" Thermoplastic Inner Core And A Steep "Positive Hardness Gradient" Thermoset Outer Core Layer

A golf ball comprising:

• an inner core layer comprising a thermoplastic highly-neutralized ionomer comprising a copolymer of ethylene and an α,β-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to neutralize the acid groups of the copolymer by 80% or greater, and having a geometric center hardness and a surface hardness to define a first hardness gradient having a first slope S1;
• an outer core layer disposed about the inner core, the outer core being formed from a homogenous thermoset composition and having an interior hardness and an outer surface hardness to define a second hardness gradient having a second slope S2;
• an inner cover layer disposed about outer core layer;
• and
• an outer cover layer disposed about the inner cover layer,
• wherein a ratio of S2 to S1 is about 10.0 or greater and wherein an angle, θ, is about 120° or greater, wherein θ is defined by the equation:
• θ
• =
• 180
• -
• (
• 180
• π
• 
• (
• tan
• -
• 1
• 
• (
• S
• 2
• )
• -
• tan
• -
• 1
• 
• (
• S
• 1
• )
• )
• )
• .