An injection molding device for producing a multicomponent injection molded product includes at least one first and at least one second outer mold plate arranged in a movable manner between an open position and a closed position. A central part arranged between the first and the second outer mold plate includes a first part which in the open position is arranged rotatable about an axis of rotation and to which first inner mold plates are attached which include first cavity segments. A second part arranged non-rotatable includes on one side in the direction of the first outer mold plate second cavity segments and on an opposite side in the direction of the second outer mold plate third cavity segments. Second inner mold plates clamp related intermediate products and in the open position are arranged displaceable in a radial direction with respect to the axis of rotation and rotatable around the second part to transport the intermediate products from the second cavity segments to the third cavity segments around the second part of the central part.

A multilayer core molding method includes an upstream process of molding using an upstream process molding apparatus, which includes a first upstream process mold including a first upstream process mold cavity surface, and a second upstream process mold including a second upstream process mold cavity surface. The upstream process includes an inner core arrangement step and a covering step to obtain an intermediate molded body, which includes the inner core, and the unvulcanized or semi-vulcanized first outer core material covering only part of a surface of the inner core and integrated with the inner core.

A multilayer core molding method for molding a multilayer core of a golf ball includes an upstream process; and a downstream process, wherein the intermediate molded body includes: an inner core; and an unvulcanized or semi-vulcanized first outer core material, and the downstream process molding apparatus includes: a first downstream process mold including a substantially hemispherical first downstream process mold cavity surface; a second downstream process mold including a substantially hemispherical second downstream process mold cavity surface; and an intermediate plate including a substantially hemispherical intermediate plate cavity surface, and a substantially hemispherical intermediate plate projecting surface, and wherein the downstream process includes: a second outer core arrangement step; an intermediate molded body arrangement; and a preparatory molding step.

A golf ball of one aspect of the present invention includes a spherical core, one or more cover members to cover the core, and a coating layer to coat a cover member configuring an outermost layer of the one or more cover members. A plurality of dimples is formed in the cover member. Shore-D hardness of the cover member is equal to or larger than 50. A 10% modulus of the coating layer is equal to or smaller than 160 kgf/cm.sup.2. Roughness is produced on a surface of the coating layer after applying a coating material over the cover member of the outermost layer A maximum height Rz of the coating layer is equal to or larger than 3 μm.

In a golf ball having a core and a cover, the core is formed of a rubber composition, has center and surface portions which are unfoamed regions and has an intermediate portion containing a foamed region. The core is produced by charging the rubber composition, which contains a blowing agent, into a first curing mold and curing under given conditions, then removing the molded rubber material in a semi-cured state from the first mold, transferring the semi-cured material to a second curing mold and curing under given conditions. The foamed region of the core deforms by a certain degree at the time of impact, decreasing the radius of gyration of the ball and enabling a lower spin rate to be achieved. The decrease in resilience due to expansion of the molded material can be held to a minimum.

A method and apparatus for forming a core for a dual core golf ball is disclosed herein. A headblock is pressed against a mold tool wherein a hemispherical protrusion of the headblock compresses a slug within a first hemispherical cavity to form a first half shell outer core component. An inner core sphere is placed within the first half shell outer core component. An upper section of the mold tool is assembled onto a lower section of the mold tool to place a second half shell outer core component within an upper hemispherical cavity over the inner core sphere within the first hemispherical cavity to form a dual core component for a golf ball.

A golf ball of one aspect of the present invention includes a spherical core, one or more cover members to cover the core, and a coating layer to coat a cover member configuring an outermost layer of the one or more cover members. A plurality of dimples is formed in the cover member of the outermost layer. Roughness is produced on a surface of the coating layer after applying a coat over the cover member of the outermost layer. An average value Fa (mm) of maximum depths of the plurality of dimples and arithmetic average roughness Ra (μm) on the surface of the coating layer, satisfy a relational expression:
−1.5×Fa+0.8≦Ra≦−1.5×Fa+1.8.

The present invention is directed to a method of forming plurality of golf balls comprising steps of: providing plurality of inner cores; forming sheet of uncured rubber; forming plurality of preps in the sheet of uncured rubber such that each prep contains a concave top surface and is detachably connected to coupling material; loading the preps and coupling material into a core mold; loading plurality of inner cores into mold such that the inner cores are aligned with the concave surface of each prep; molding the preps about the inner cores to form outer core layers; and forming covers about outer core layers.

Dual core golf ball constructions achieving consistent and repeatable concentricity by incorporating/using an assembly of dual core components comprising a solid spherical inner core component and three outer core components that are collectively compression molded about the solid spherical inner core component to create an outer core layer thereabout. The three outer core components include a first half-shell, a second half-shell; and a ring-shaped securing plate such that the solid spherical inner core component is immovably centered within the outer core layer. Each of the first half-shell, the ring-shaped securing plate, and the second half-shell is comprised of the same rubber composition(s) and possess strong cohesive and adhesive bonds at parting lines between the three molded assembly parts and collectively create an outer core layer having one or more uniform property profile, such as a hardness gradient throughout, without interruption at parting lines between the three outer core components.

Golf ball methods and molds for quickly and efficiently eliminating air/gas from within a mold during golf ball manufacture and the improved golf balls resulting therefrom.