JP2001259083A - Method for verifying concentricity of multiple-layered golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for determining the concentricity of a multipiece golf ball without damaging a golf ball. SOLUTION: The method for checking the concentricity of a golf ball having a boundary layer or cover doped with barium or bismuth is disclosed. This method makes the concentricity of the golf ball sure by determining the thickness of the cover in various positions by utilizing an X-ray image apparatus. The boundary layer is an ionomer blend into which the barium or bismuth of an amount of 5 to 15% of the ionomer material is doped and the cover consists of a thermosetting polyurethane material. The cover is otherwise doped with the barium or bismuth and the boundary layer is undoped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a golf ball,
The present invention relates to a golf ball cover and a boundary layer material, and more particularly, to a method of confirming concentricity of a golf ball using an X-ray image of barium doped in the boundary layer.

[0002]

2. Description of the Related Art Conventionally, golf balls have been manufactured by molding a cover around a core. The core is wound or solid. The wound core usually consists of an elastic thread wound around a solid or liquid center. Unlike a wound core, a solid core does not have a layer of wound elastic yarn. Solid cores usually have a single piece center or a solid center covered by one or more mantle or boundary layer materials.

[0003] The cover is manufactured by injection molding, compression molding or casting onto a core. Generally, injection molding requires a mold having at least a pair of mold cavities, for example, a first mold cavity and a second mold cavity, and is adapted to form a spherical recess. In addition, the mold has one or more mold cavity pairs.

In a typical injection molding process, each mold cavity has a retractable locating pin that holds the core at the spherical center of the mold cavity pair.

[0005] Once the core is positioned in the first mold cavity, a corresponding second mold cavity mates with the first mold cavity to close the mold. The cover material is then poured into the closed mold. While the cover material is fluid, the locating pins are retracted and the material fills the holes created by the pins. When the material is at least partially cured, the covered core is removed from the core.

[0006] Like injection molding, compression molding typically requires many pairs of mold cavities, each pair having first and second mold cavities that fit to form a spherical recess. In one typical compression molding process, the cover material is preformed on the half shells by injecting each pair of compression mold cavities. The core is placed between the cover material half shell and the mold and closed. Thereafter, the combination of core and cover is subjected to heat and pressure to join the cover half-shells to form the entire cover.

[0007] Similar to the process referenced above, the casting process also utilizes pairs of mold cavities. In the casting process, a cover material is introduced into each pair of first mold cavities.
Thereafter, the core is held in place (eg, by an overhanging vacuum or suction device) and brought into contact with the cover such that the core is located at the spherical center of the mold cavity pair. Once the cover material has hardened to at least a partial drop (eg, if the core is substantially immobile), the core is released, the cover material is introduced into each pair of second mold cavities, and the molds are mated. close. Heat and pressure are then applied to the closed mold to cure the cover material, thus forming a cover on the core. In injection molding, compression molding, and casting, there is usually a negative dimple pattern in the molding cavity, causing the dimple pattern to form on the cover during the molding process.

Materials previously used as golf ball covers include balata (natural and synthetic), gutta percha, ionomer resins (eg, Surlyn® from DuPont) and polyurethane. Balata is a benchmark cover material for sound (ie, the sound generated when a ball is hit with a golf club) and feel (ie, the sensation imparted to a golfer when hitting the ball).
Natural balata is derived from the briam gum tree, while synthetic balata is derived from petroleum compounds. Compared to other cover materials, balata is expensive and golf balls covered with balata tend to be less durable (ie, less ablation and shear resistant). Gutta percha is derived from a Malaysian sapodilla tree. A golf ball covered with Gutta Percha feels more tactile and rougher than a golf ball covered with balata. Compared to balata, ionomer resins are usually less expensive and have better durability. However, golf balls having ionomer resins generally have poor sound and feel, especially as compared to balata covers. Polyurethane-covered golf balls have greater durability and a better feel than ionomer covers, but polyurethanes are relatively expensive and require skilled skills to manufacture golf balls.

Whatever the material used, the essential requirement in manufacturing a golf ball is to accurately balance the golf ball so that the golf ball will not fly during flight after being hit with a golf club. This is to avoid hooking or slicing. In addition, golf balls that are not correctly balanced will be out of alignment during putting. The need to accurately balance a golf ball is further complicated by the tuples golf ball, and is particularly complex with golf balls that have a high cost of casting. Many thermoset layers are centered during insertion of the core into the hollow thermoset mixture, so that the core moves during the casting process. Detection of an off-center golf ball is difficult and sometimes damages the golf ball itself.

[0010] Barite fillers and other barium-containing components have been utilized in golf balls in the past. U.S. Pat. No. 2,259,060 to Brown; U.S. Pat. No. 3,883,145 to Cox et al .; U.S. Pat.
All documents 609,532 describe the use of barium sulfate and barite in the core as fillers for weight purposes to improve balance. Yamada et al., US Pat. No. 4,679,794, Sullivan US Pat. No. 4,884,814, and Yamada US Pat. No. 5,274,041 all from 1 to 10 parts by weight. The use of barium sulfate as the pigment used in golf ball covers is described with varying amounts of resin.
No. 5,704,854 to Higuchi et al. Discloses the use of barium sulfate as a weight adjusting filler.

[0011] However, the prior art does not disclose the use of barium sulfate to determine the concentricity of a golf ball.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for determining the concentricity of a multi-piece golf ball without damaging the golf ball. I do.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a golf ball having a doped boundary layer of an X-ray instrument for measuring the concentricity of the boundary layer and the cover with respect to the core. Achieved.

[0014] One embodiment of the present invention relates to a method for confirming concentricity of a golf ball cover. The method includes forming a boundary layer on the core. The boundary layer is made of a polymer material doped with barium or bismuth. A cover is then formed over the doped boundary layer, resulting in a golf ball with the cover.
Next, the golf ball with the cover is placed in the X-ray imaging apparatus. Finally, the covered golf ball is illuminated in an X-ray imaging machine to form an image of the doped boundary layer for the cover and the core, and to calculate the cover thickness.

The present invention also eliminates a golf ball with a cover having an unacceptable cover thickness. further,
The method includes measuring the thickness of the cover at two or more locations to calculate concentricity. Further, the method includes detecting an outer circumference of the doped boundary layer, detecting an outer circumference of the cover, and measuring a thickness of the cover.

Another embodiment of the present invention relates to a method for confirming concentricity of a multi-piece golf ball.
The method includes forming a boundary layer on a solid core of a polybutadiene material. The boundary layer includes the ionomer blend material doped with barium in an amount of 5 to 15 percent of the ionomer blend material. Also,
The method includes forming a thermoset polyurethane cover over the doped boundary layer, resulting in a covered golf ball. Next, the golf ball with the cover is placed in the X-ray imaging apparatus. Finally, the golf ball with the cover was irradiated in an X-ray imaging apparatus, and an image of the boundary layer doped with the cover and the core was taken to determine the cover thickness.

Having briefly described the invention, the above and other objects, features and advantages thereof will become apparent to those skilled in the art from the following detailed description of the invention, when taken in conjunction with the accompanying drawings.

[0018]

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel method for determining the concentricity of a golf ball cover and a boundary layer with respect to a core without damaging the golf ball. The present invention relates to X
Observe multi-piece golf balls using line imaging equipment and have enhanced images due to doping of certain boundary layers with barium, bismuth, or mixtures thereof.

The golf ball of the present invention generally has a solid core, one or more boundaries or mantle layers, and a cover. In a preferred embodiment, the golf ball of the present invention has a solid core, a boundary layer (preferably a thermoplastic material), and a polyurethane cover. All embodiments of the present invention have a cover made by casting polyurethane over the core / boundary layer combination.

As shown in FIG. 1, the golf ball 10 of the first embodiment has a cover 14 on an inner core 12 and a boundary layer 13. The boundary layer 13 is a single layer or a multilayer as shown. In this embodiment, the inner core 12 is preferably formed of a single-layer solid core by compression molding, the boundary layer 13 is preferably manufactured by injection molding on the core, and the cover 14 is Core 1
Preferably, it is cast on 2 (more preferably pre-heated).

The solid core 12 of the golf ball 10 generally includes a base rubber, a crosslinking agent, a free radical initiator,
It has a blend of one or more fillers and a treatment acid. Suitable base rubbers have at least about 90%, preferably 9%,
Polybutadiene having a cis-1,4 content of 8% or more. Such materials are well-known to those skilled in the art.

Alternatively, core 12 may be a hollow shell or a liquid-filled core. Further, the core 12 has a multilayer having a changed hardness. The core 12 has a diameter in the range of 1.40 inches to 1.55 inches, and the additional H has a diameter ranging from 1.48 inches to 1.52 inches. The diameter of the core 12 is measured before being placed on the boundary layer 13. Measuring the diameter of the core 12 before placing it on the boundary layer 13 is performed by using the boundary layer 13 and the cover 14.
To ensure the accuracy of subsequent measurements.

As mentioned above, the present invention provides at least one boundary layer 13 which is preferably made of thermoplastic (eg, thermoplastic or thermoplastic elastomer) or thermoplastic (eg, containing metal, non-metal or both). It is preferable to have However, golf ball 10 has a number of boundary layers 13 disposed between core 12 and cover 14. Preferably, the boundary layer 13
Consists of at least one thermoplastic material containing organic chain molecules and metal ions. Metal ions are, for example, sodium, zinc, magnesium, lithium, potassium, cesium, any polar metal ion that serves as a reversible crosslinking site and provides a high level of elasticity and impact resistance. Suitable commercially available thermoplastic materials are ionomers based on ethylene copolymers and containing carboxyl groups with metal ions as described above. The acid levels of such suitable ionomers are neutralized to control elasticity, impact resistance and other properties. In addition, certain other fillers of the ionomer carrier can be utilized to modify (eg, increase) the specific gravity of the thermoplastic blend to control the moment of inertia and other properties. Typical commercially available thermoplastic materials used for the boundary layer 13 of the golf ball 10 of the present invention are, for example, the following materials and / or blends of the following materials: HYTREL® and / or Or HYLENE® (a product of DuPont, Wilmington, Del.), PEBEX® (a product of Elphatochem, Philadelphia, Pa.), Surlyn® (Dupont products),
ESCOR (registered trademark) or Iotek (IOTEK)
(Registered trademark)) (a product of Exxon Chemical Company, Houston, Texas).

The Shore D hardness of the boundary layer 13 should be about 65 or less. The boundary layer 13 has a Shore D of about 50 to 65
It is preferable to have a hardness of In a preferred embodiment, the boundary layer 13 has a Shore D hardness in the range of about 52-65. One reason a boundary layer having a Shore D hardness of 65 or less is preferred is because it can improve the feel of the resulting golf ball. Also, the boundary layer 13 preferably comprises a blend of Surlyn® (ionomer. Table 1 shows the physical data of the suitable boundary layer 13 produced and introduced in a specific embodiment of the golf ball 10 of the present invention. As shown in Table 1 below, the boundary layer 13 having a low Shore D hardness tends to have a low flexural modulus.

[0025]

[Table 1] Surlyn® 8150, 9150 and 6320
Are, respectively, an ionomer resin composed of sodium-neutralized ethylene / methacrylic acid, an ionomer resin composed of zinc-neutralized ethylene /, the obtained acrylic acid, and ethylene, methacrylic acid and n-part partially neutralized with magnesium. An ionomer resin consisting of a terpolymer of vaginal acrylate, all of which are commercially available from DuPont, Wilmington, Del.

As shown in Table 1, all boundary layers 13 of the example have a baryt containing a predetermined amount of barium.
e) having a predetermined amount. The belite mixture is 5 to 10 percent of the ionomer resin, preferably 8% of the ionomer resin.
To 9% by weight. One suitable belite mixture is 38534X1 (trademark), consisting of 80% belite and 20% ionomer, commercially available from Amelychem Inc., of Cuyahoga Falls, Ohio. The specific gravity of each boundary layer in Table 1 was 1.007. Table 1
Was determined according to ASTM D790. The Shore D hardness listed in Table 1 is ASTM D22
40.

The boundary layer 13 is formed by a conventional injection molding machine.
Preferably, it is injection molded on the core 12. Core 12
Is centered using a retractable pin in the injection molding cavity. The cavities are filled with thermoplastic material, and then the pins are retracted and the voids left by the pins are filled with thermoplastic material. This makes it possible to position the center of the core with considerable certainty during the formation of the boundary layer 13.

In a preferred embodiment, the cover 14 of the golf ball 10 of the present invention is preferably a castable thermoset polyurethane elastomer. The preferred polyurethane utilized herein consists of a prepolymer based on PPDI reacted with a curing agent. PPD
I-based prepolymers are formed from PPDI and polyols such as ester polyols, polyether polyols or blends thereof. A preferred polyol is polycaprolactone. The curing agent may be a diol (eg, 1,4-butadiene, trimethylpropanol), a mixture of diols (eg, 1,4-butadiene diol and ethylene glycol, or other suitable glycol), hydroquinone, a mixture of hydroquinones. , A mixture of a triol and its triols, a diamine, a mixture of its diamines, an oligomeric diamine,
There are triamines, many or all blends of the above materials. Specifically, the cover 14 of the golf ball 10 of the present invention includes a prepolymer based on PPDI,
More preferably, it consists of a polyurethane derived from a mixture cured with a mixture of diols, such as a blend of 1,4-butadiene diol and glycol.

Although the golf ball cover 14 of the present invention is preferably manufactured by a casting process, the cover material may be provided on the boundary layer 13 and the core 12 as a thermoplastic polyurethane for injection molding of the cover 14. The resulting product is modified using conventional methods to apply the desired thermoplastic material to the cover layer 1 on the boundary layer 13 and core 12.
4 for injection molding.

The cover 14 of the present invention has a thickness between about 0.02 and 0.09 inches, preferably between 0.02 and 0.065 inches, and more preferably between 0.02 and 0.04 inches. It has a thickness of inches.

The diameter of the core 12 of the present invention and the thickness of the boundary layer 13 and the cover 14 depend on the desired diameter of the golf ball 10. The inner core 12 preferably has a diameter in the range of about 1.35 to 1.70 inches, and the boundary layer 13 preferably has a wall thickness in the range of about 0.02 to 0.09 inches. The desired diameter of the golf ball 10 is about 1.6
If 8 inches, the core 12 preferably has a diameter in the range of about 1.40 to 1.65 inches, and the boundary layer 13 has a wall thickness in the range of about 0.02 to 0.075 inches. More preferably, the core 12 has a diameter in the range of about 1.45 to 1.60 inches, and the boundary layer 13 has a wall thickness in the range of about 0.02 to 0.067 inches. More preferred. If the desired diameter of golf ball 10 is about 1.8 inches, core 12 preferably has a diameter in the range of about 1.55 to 1.72 inches, and boundary layer 13 has a diameter of about 0.02 to 0.09 inches. Preferably, the wall thickness is in the range of inches, more preferably, the core 12 has a diameter in the range of about 1.6 to 1.72 inches, and the boundary layer 13 is in the range of about 0.02 to 0.3 inches.
More preferably, it has a wall thickness in the range of 06 inches.

In the production of the golf ball of the present invention, the boundary layer 13 is preferably injection molded around the inner core 12 by a conventional method. As a result, a golf ball precursor comprising the combination of the inner core 12 and the boundary layer 13 is formed. The body product is completed. The combination of inner core 12 and boundary layer 13 preferably has an overall diameter in the range of about 1.46 to 1.76 inches, depending on the desired diameter of golf ball 10 as well. If the desired diameter of golf ball 10 is about 1.68 inches, the combination of core 12 and boundary layer 13 will be about 1.55 inches.
Preferably, it has an overall diameter in the range of about 1.6 to 1.64 inches, and more preferably in the range of about 1.6 to 1.64 inches. If the desired diameter of golf ball 10 is about 1.8 inches, the combination of core 12 and boundary layer 13 more preferably has an overall diameter in the range of about 1.64 to 1.67 inches, and More preferably, it is in the range of 1.72 to 1.76 inches.

In a preferred manufacturing process, the polyurethane cover material is introduced into the first cavity of the mold cavity at T0. After about 30 to 90 (ie, T0 + 30 to 90 seconds, ie, T1), the golf ball precursor product (core 12 and boundary layer 13) is placed in the first mold so that it is the spherical center of the mold cavity pair. It was held in contact with the cover material of the cavity (for example by a suction device). The cover material is at least partially cured (typically up to about 10 to 30 seconds, ie,
About T1 + 10 to 30 seconds, ie, T2), then release the golf ball precursor product. At the same time, about 3 before T2
Preferably, in a time of 0 to 90 seconds, the cover material is introduced into the second cavity of the mold cavity pair, after which the mold is closed (so that the first mold cavity is compatible with the second mold cavity);
The cover material is cured by heating and pressing at about 140 to 220 ° F. for about 2 to 10 minutes at a pressure of about 1/3 to 2 tons per mold cavity, forming the cover 14 on the golf ball precursor product. The ball with the cover is then demolded, cooled and post-cured.

After removal from the mold, each golf ball 10 is moved to the X-ray imaging device 20, as shown in FIG. The barrier layer 13 doped with barium or bismuth improves the strength of the image of the golf ball 10 on the screen, and the boundary layer 13 is distinguished from the cover 14. Therefore, the inner periphery 22 and the outer periphery 24 of the boundary layer 13 are detected,
The thickness of the boundary layer 13 is determined. Further, the outer periphery 26 of the cover 14 is detected, and this measurement is performed on the outer periphery 24
Of the cover 14 to give the thickness of the cover 14. The measurements are performed at various points, indicated by the line 50 of the golf ball, and the boundary layer 13 and cover 14
It is confirmed whether or not it is within the concentricity design parameters around 2. In the preferred embodiment, measurements are taken at eight intervals, with 100 or more measurements taken at each interval. The information is edited by the processing system of the X-ray imaging apparatus 20, and the golf balls are grouped according to whether they are within an allowable range. As long as the golf ball 10 is not within the designed concentricity range, the golf ball 10 is rejected and discarded from the X-ray machine 20 via the reject chute for material recovery. As long as the golf ball 10 is perfect from a concentric point of view,
It is transported to the golf ball finishing process.

For example, the cover 14 is measured at various points to determine whether the thickness at each point is substantially equal. One suitable acceptable thickness variation is 0.0
03 inches. That is, the thickness of the cover 14 is 30
No change of 0.003 inches or more at any of the points 33 to 33. Thus, the thickness of point 30 is 0.025 inches, the thickness of point 31 is 0.024 inches, the thickness of point 32 is 0.023 inches, and the thickness of point 33 is 0.025 inches.
If so, the cover 14 is within acceptable concentric design parameters. Alternatively, point 30
Is 0.025 inch, the thickness at point 31 is 0.024 inch, the thickness at point 32 is 0.023, and the thickness at point 33 is 0.028. If so, the cover 14 would not be within the acceptable design parameters for concentricity. The latter example shows that if the core 12 is not exactly centered, the golf ball 10 will lose balance and exhibit unacceptable behavior for its purpose. Without departing from the scope and spirit of the invention,
It is understood by those skilled in the art that the concentricity design parameter is set so that the variation value is around 0.003.

Alternatively, the cover 14 contains a barium or bismuth material to be used to determine concentricity. In this embodiment, the boundary layer 13 is made of a thermosetting material such as polyurethane, and the cover 14 is made of an ionomer material. Such golf balls are described in co-pending U.S. Patent Application Serial No. 09 / 361,695, filed July 27, 1999, entitled "Multi-Layer Golf Ball," which is incorporated herein by reference. Golf Bal
l) ". Thus, the same method is used to distinguish the undoped boundary layer 13 from the barium or bismuth doped cover 14.

While the embodiments of the invention have been illustrated and described, various modifications can be made without departing from the scope of the invention, and all such modifications and their equivalents are included herein. You. For example, the size and thickness ranges are:
It also applies to balls having a finish diameter of about 1.68 inches, consistent with the current rules of the United States Golf Boundary. However, balls of various sizes are considered to be within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view of a golf ball of the present invention having a cutout indicating a core, a boundary layer, and a cover.

FIG. 2 illustrates an X-ray image of the golf ball of the present invention observed by an X-ray imaging apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Golf ball 12 Inner core 13 Boundary layer 14 Cover 20 X-ray imaging device 22 Inner periphery of boundary layer 24 Outer periphery of boundary layer 26 Outer periphery of cover

 ──────────────────────────────────────────────────続 き Continuing the front page (72) Inventor Pijash Kay Dewansy 2285 Lazarford Road, Carlsbad, California 92008-8815, USA

Claims (20)

[Claims] 1. A method for determining concentricity of a golf ball cover, comprising: forming a boundary layer on a core containing a barium or bismuth-doped polymer material; forming a golf ball with a cover. Forming a cover on the doped boundary layer; placing the golf ball with the cover on an X-ray imaging device; forming an image of the doped boundary layer with respect to the cover and core. Irradiating a covered golf ball in the X-ray imaging apparatus to determine the thickness of the cover. 2. The method of claim 1, further comprising the step of removing golf balls with the cover having an unacceptable cover thickness. 3. The method of claim 1, further comprising measuring the thickness of the cover at two or more locations to determine concentricity. 4. The method of claim 1, further comprising: detecting an outer periphery of the doped boundary layer; detecting an outer periphery of the cover; and measuring a thickness of the cover. Confirmation method described in. 5. A method for detecting an inner periphery of the doped boundary layer to fix the position of the core, and detecting an outer periphery of the doped boundary layer to fix the position of the cover. The method of claim 1, further comprising: determining the concentricity of the cover and the doped boundary layer with respect to the core. 6. The method of claim 1, wherein the boundary layer is a blend of barium-doped ionomer in an amount of at least 5 percent of the ionomer blend material. 7. The method of claim 1, wherein the boundary layer is a blend of barium-doped ionomer in an amount of 5 to 15 percent of the ionomer blend material. 8. The method according to claim 1, wherein the cover is made of a thermosetting material. 9. The method according to claim 8, wherein said cover is made of a polyurethane thermosetting material. 10. The method of claim 1, wherein said cover has a thickness in a range of 0.020 inches to 0.05 inches. 11. The core according to claim 1, wherein the core is 1.40 inches to 1.5 inches.
The method of claim 1, wherein the golf ball has a diameter in the range of 5 inches and the overall diameter of the finished golf ball is approximately 1.68 inches. 12. The method of claim 2, wherein the thickness of the cover has a variation of 0.003 inches or less. 13. The method of claim 1, wherein said core is solid and comprises a polybutadiene material. 14. A method for confirming concentricity of a multi-piece golf ball, comprising: a solid core comprising a polybutadiene material, wherein the ionomer blend material is doped with barium in an amount of 5 to 15 percent of the ionomer blend material. Forming a boundary layer; forming a thermosetting polyurethane cover on the doped boundary layer so as to produce a golf ball with a cover; and mounting the golf ball with the cover on an X-ray imaging apparatus. Forming an image of the doped boundary layer with respect to the cover and the core, and determining a thickness of the cover.
Irradiating a golf ball with a cover in the X-ray imaging apparatus. 15. The method according to claim 14, further comprising the step of measuring the thickness of the cover at two or more positions to determine concentricity. 16. Detecting the outer perimeter of the doped boundary layer; detecting the outer perimeter of the cover;
The method according to claim 14, further comprising: measuring a thickness of the cover. 17. A method for detecting an inner periphery of the doped boundary layer to fix the position of the core, and detecting an outer periphery of the doped boundary layer to fix the position of the cover. Determining the concentricity of the cover and the doped boundary layer with respect to the core;
The confirmation method according to claim 14, further comprising: 18. The method of claim 14, wherein the thickness of the cover has a variation of 0.003 inches or less. 19. The core according to claim 1, wherein the core is between 1.40 inches and 1.5 inches.
15. The method of claim 14, wherein the golf ball has a diameter in the range of 5 inches and the overall diameter of the finished golf ball is approximately 1.68 inches. 20. A method of confirming concentricity of a multi-piece golf ball, comprising the steps of: forming a boundary layer on a solid core; Forming a cover comprising a material doped with 15100 separation amounts of barium or bismuth; placing the golf ball with the cover on an x-ray imaging device; and doping the golf ball with the cover with respect to the boundary layer and the core. Forming an image on the cover, and irradiating a golf ball with a cover in the X-ray imaging apparatus so as to determine the thickness of the cover and concentricity of the golf ball.