Games using tangible projectile – Golf – Ball
Reexamination Certificate
2001-04-13
2003-11-11
Sewell, Paul T. (Department: 3711)
Games using tangible projectile
Golf
Ball
C473S351000
Reexamination Certificate
active
06645088
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a reaction injection molding process and compositions for forming golf equipment or components thereof, particularly for forming layers of golf balls in one embodiment. The reaction injection molding process of the invention involves providing at least two reactable components that have a fast reaction time and injecting them with sufficient speed after they are mixed so that they are polymerized, solidified, or gelled in a mold cavity.
BACKGROUND OF THE INVENTION
It is well known to even the average golfer that the equipment used in playing the game is subject to a great deal of friction, impact, and other stresses during a typical round of golf. Both the performance and the useful life of such equipment would benefit from the use of materials having increased durability. For instance, many types of golf clubs, such as putters, drivers, and wedges, contain polymer inserts in the face of the club. Since the club face directly strikes a golf ball thousands of times over the life of the club, improved durability is of great importance. Additionally, club components, such as shafts, grips, and hosels, undergo significant stress during a golf swing and contact with a golf ball and, therefore, could stand to benefit from more durable materials.
Of course, golf balls are repeatedly struck against very hard objects as well, including golf clubs, and it is very desirable to maintain their performance properties over as long a period of time as possible. Golfers of all skill levels seek out a variety of properties in their golf balls for a variety of golfing situations, although resilience, durability, and longevity are always important. The type of materials used in forming the different golf ball layers can greatly affect these properties, as well as the “click,” “feel,” spin, initial velocity, “playability,” and other properties.
Golf equipment is typically formulated from a variety of different materials. Most conventional materials, however, do not entirely address the problems associated with stress, durability, and repeated impact. Therefore, it is clear that improved materials, having material properties that address these preferred physical requirements, are necessary.
In addition, the manner in which golf equipment, or components thereof, is fabricated can affect certain properties of the materials, for example, such as durability. The types of chemistries present in the golf equipment materials can also sometimes indicate or dictate the preferred method of fabrication used to form them.
Particularly with respect to polyurethane-containing materials, commercially available golf equipment or components, especially for golf balls, can be currently made by casting or injection molding processes. The nature of current casting processes is such that materials that require a relatively long time (in comparison to other fabrication methods) to sufficiently solidify, i.e., react thoroughly. As a result, materials or compounds with particular chemistries that react or solidify relatively quickly are generally restricted from use in commercial casting processes, particularly in the golf art.
By using an alternative fabrication technique, reaction injection molding, as opposed to traditional injection molding, thermosetting materials and/or materials with relatively quick reaction or solidification times can be processed into certain articles. Reaction injection molding processes, due to the nature of the chemistries of the materials used, tend to result in decreased fabrication times, and can facilitate a decrease in the cost of fabricating such articles. The technique of reaction injection molding (RIM) using a variety of materials has been demonstrated in various publications.
For example, U.S. Pat. No. 4,762,322 discloses golf clubs with heads that can be made from a hollow metal shell or a low density, high strength material, such as a reaction injection molded polyurethane, formed around weighted inserts.
With respect to manufacture of golf balls, RIM has been disclosed, for example, in International Publication No. WO 00/57962, which claims golf balls, and processes for making such balls, comprising a reaction injection molded material, such as polyurethanes/polyureas.
In addition, U.S. Pat. No. 6,083,119 discloses a multi-layer golf ball with an inner and outer cover layer, at least one of which can contain a reaction injection molded polyurethane material.
U.S. Pat. Nos. 4,695,055 and 4,878,674 also disclose illuminated, translucent golf balls having a permanent diametric hole into which a chemiluminescent light stick is added, so that the golf balls may be visible in the dark. These golf balls can be fabricated by a method such as reaction injection molding.
Additionally, conventional non-reactive injection molding can be used to form relatively thin layers of material in golf equipment, or components thereof, generally in golf balls. Examples of thin components or layers made by conventional non-reactive injection molding have also been demonstrated in various publications.
SUMMARY OF THE INVENTION
One aspect of the invention relates to a method for forming golf equipment, or a portion thereof, preferably for forming one or more layers of a golf ball, including: providing a first reactable component including an isocyanate-reactive component, preferably including a polyisocyanate or including a prepolymer or quasi-prepolymer containing the reaction product of a polyol, polyamine, or epoxy-containing compound with at least one polyisocyanate, and a second reactable component including at least one of a polyol, polyamine, or epoxy-containing compound; combining the reactable components together to form a reactive mixture; and injecting the reactive mixture into a cavity or mold having a desired shape within a time sufficient to avoid substantial gelation or solidification. Advantageously, the polymerization, solidification, or gelation times of the reactive mixture of the present invention should typically be within about 60 seconds, preferably within about 45 seconds, more preferably from about 0.25 seconds to 30 seconds, most preferably from about 0.5 seconds to 15 seconds, after combining, either at ambient or elevated temperatures. In various other embodiments, the polymerization, solidification, or gelation times of the reactive mixture of the present invention are from about 1 second to 10 seconds or from about 1 second to 5 seconds after combining.
In a preferred embodiment, each of the at least two reactable components have a viscosity not more than about 20,000 cPs, preferably not more than about 15,000 cPs, more preferably from about 25 cPs to 10,000 cPs, most preferably from about 25 cPs to 5,000 cPs, all at ambient or elevated temperatures. In another preferred embodiment, all the reactable components, or mixtures thereof each contained separately, that form the reactive mixture have viscosities similar to those of the first and second reactable components at ambient or elevated temperatures. In yet another preferred embodiment, each reactable component has a viscosity not more than about 5,000 cPs, preferably not more than about 1,000 cPs, at a temperature of about 150° F. In one embodiment, the mixture is injected into the mold or cavity at an injection pressure of not more than about 2,500 psi. In another embodiment, the viscosity index of any two of the reactable components is from about 1000 to 1, preferably from about 800 to 20, at ambient temperature or at a temperature at which the reactable components are combined.
In one preferred embodiment, the isocyanate-containing compound or the polyisocyanate includes a diisocyanate having the generic structure:
O═C═N—R—N═C═O
where R is a cyclic, aromatic, or linear branched or unbranched hydrocarbon chain each having a moiety containing from about 1 to 20 carbon atoms. When multiple aromatic or cyclic groups are present, linear and/or branched hydrocarbons containing from about 1 to 10 carbon atoms can be present as spacers between the aromatic or
Harris Kevin M.
Kuntimaddi Manjari
Rajagopalan Murali
Wu Shenshen
Acushnet Company
Hunter, Jr. Alvin A.
Swidler Berlin Shereff & Friedman, LLP
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