JPH0113863B2 - - Google Patents

Description

[Detailed description of the invention]

It is well known that the game of golf is played using a set of clubs of different lengths, with the longest club being called the "wood" and the relatively short one being called the "iron." . It is also well known that a golf club consists of a single shaft with a wrapping at one end forming a "grip", the wrapping being made of leather, rubber, etc. A so-called "head" is attached to the other end of the shaft.
During the swing, this head becomes the hitting surface element of the golf ball. The shaft may be made of metal (eg, steel), graphite, fiberglass, etc. As mentioned above, the heads of the longer clubs in a club set are generally made of wood, while the heads of the shorter clubs are made of iron. The present invention relates to a club head, known as a "wood", having a traditional shape as shown at 1 and 3 in FIGS. 1 and 2, respectively. To clarify the meaning of the term, the term "wood" is used here, unless otherwise specified, whether it is made of wood (e.g. persimmon wood), aluminum, plastic or any other material. Even though
We shall generally refer to a "club head" shaped as shown in FIGS. 1 and 2 above. In this context, the present invention relates to golf club heads made entirely or primarily of polyurethane wood, or in other words, urethane polymers. As is clear from FIGS. 1 and 2, a standard wood is provided with a ball hitting surface 5 called a "face" which has a flat leading end (see FIG. 2).
The face of FIG. 1 is provided with a number of parallel, horizontal grooves 7. As shown in FIG.
1 (referred to as the "toe") and a right (rear) part 13 (referred to as the "heel"). The bottom of the wood (only the leading edge is marked 15 in Figure 2)
) is called the “sole” and extends from the main body (block) of the wood 3 in Fig. 2 to the shaft 17.
The elongated section 19 extending up to (only the cutout is shown) is called the "net". The center of this net is hollow, and the shaft 17 is fitted into it. Said central part 9 of the wood face 5 shown in FIG. shows a plate called the "insert" (delineated by line 21) fitted into a recess (not shown) in the center of the face of the face, which insert is fixed to the face by screws 23. There is. Of course, it is imperative that the front surface of the insert, the toe 11 surface, and the heel 13 surface provide an overall uniform and smooth club face. This minimizes the deflection of the golf ball when it hits a portion other than the sweet spot. The purpose of providing the insert is to improve durability and increase flight distance. Inserts have been made from a variety of materials, including certain metals, ivory, polymers (eg, phenolic resins), and the like. Before and since Harry Vardon (1870-1937), one of the most timeless golfers,
Utsudo have traditionally been made of solid wood blocks, but recent technology has changed the structure of these blocks by stacking thin wooden sheets and rigidly laminating them with a thin film of adhesive resin. came out. The laminate thus obtained is shaped into a wood. Although this modification was very successful, other materials used to make wood have not been as successful for various reasons. Wood has been made of, for example, aluminum, plastic (acrylonitrile-butadiene-styrene (ABS)), or other metals or polymers. When using such woods, the distance in question, which the manufacturer emphasizes, increases. However, players complain that the impact feels poor and that control and accuracy are lost. For example, players report that even when making a perfect shot, there is a so-called "shot" feeling at the moment of impact, and the contact (contact between the club face and the golf ball) feels short. Players also suffer from vibrations and a resulting reduction in distance if the ball does not hit the sweet spot of the wood at the moment of impact, i.e. if the ball hits the toe or heel of the wood. Ta. Players believe that the above differences in control and accuracy between traditional woods and commercial woods with the drawbacks mentioned above are such that the majority of players prefer long irons (1st or 2nd) and short irons (6th or 6th irons). He often explains that it is similar to the difference in the feeling of impact that he experiences between himself and others (No. 9). Modern irons range from No. 1 to No. 9, with No. 1 iron being the longest and No. 9 iron being the shortest. As is well known, compared to short irons, long irons not only have longer shafts, but also have lighter, thinner heads, narrower widths, and smaller lofts. A long iron with a low loft has a shorter contact time with the ball than a short iron with a higher loft. The shorter the contact time, the greater the vibration.
Conversely, as the contact time increases, the vibration decreases. In addition to the above-described type of insert shown in FIG. 1, the traditional wood and modern laminated wood generally include a metal sole plate for durability. The leading edge of this plate is indicated at 25 in FIG.
Additionally, various impregnations and coatings are used to protect wood. However, even with these modifications to traditional wood blocks and laminated wood, the wood is easily damaged. For example, wood faces and other surfaces are easily scratched and nicked, and wood necks are prone to cracking. As shown in Figure 1,
Sleeve 27 usually made of plastic
It is customary to cover the meeting area of the club's neck 19 (shown in Figure 2) and shaft 17 to provide a smooth appearance.
This sleeve is also prone to cracking. Even with careful craftsmanship and quality control, it is difficult to ensure the reproducibility of a given club head design, such as uniform lofts and lies, uniform club faces, etc. In this field of technology, it has been necessary to overcome numerous complex steps (sometimes over 100) to create a satisfactory golf club. Nevertheless, severe drawbacks must be overcome, including changes in club head weight due to absorption of large amounts of moisture. Weight changes and the aforementioned bruising and damage are particularly problematic in the case of fairways, which are used without tees and often come into contact with wet grass, roots, or even stones. Generally, the first edge of the airway is the driver (also called the first edge).
Even if the sole plate 25 (FIG. 1) protects the bottom of the sole plate 25,
much more susceptible to damage. Additionally, such elements, such as the insert in the sweet spot of the wood face, especially if it is screwed in, make a difference in energy recovery when the golf ball does not strike the sweet spot directly. This is why experienced golfers feel nostalgic about the early insert-less wood aces. Based on the above, the optimal conditions for golf balls for experienced players are, among other things: (i) good energy recovery, high initial velocity and flight distance of the golf ball, and minimum shock and vibration; ) increasing control and accuracy as monitored by the feel of impact; and (iii)
I think it's durability. It is clear that current clubs do not satisfy at least one of these characteristics. The purpose of the present invention is to
In terms of manufacturing wood, it is important to achieve all of these properties, including its reproducibility. As will be seen below, the invention surprisingly achieves the above objectives without the need for particularly hard materials at impact. A search of related technology in the records of the United States Patent and Trademark Office revealed the following United States patents.

[Table] The first three of these patents are related, but the Jepson et al. patent seems to be the most related. This patent discloses a general golf club of the above type with a polyurethane insert ("striking plate") with enhanced physicochemical properties (see claim 1 of the patent).
reference). As will become clear below, the golf club of the present invention differs materially from that of Jepson et al. For example, the disclosure of this patent is directed primarily to polyurethane inserts. Two remaining patents: Dusbiber and DiSalvo
The et al. patents relate, among other things, to golf balls made from diisocyanate monomers. Rozmus' patent concerns a specially weighted golf club to help achieve accuracy. This weight is placed inside the club head.
It is arranged on each side thereof and fixed there, as it were, by means of epoxy resin and ceramic material, for example. The Senne patent is also irrelevant. It is simply made of wood, preferably a wood core with a face and a recess in its central part for the insertion of an insert, the core being surrounded by a polymer shell except for the toe and heel parts. completely covered. A metal plate is mounted on top of the core's polymer-coated sole. What is really interesting in confirming the above point is the following passage (Senne patent, column 2, lines 13-24). "Solid clubs molded from synthetic resins have been manufactured industrially, but these are not satisfactory according to the preferred standards of golf club performance. These plastics are, for example, nylon, acrylonitrile-butadiene-styrene - Copolymers, polycarbonates.The density of these plastics is greater than that of wood (more than 100%), so
It was necessary to create an air hole in the center of the solid plastic head. The biggest drawbacks of this structure are that it does not produce a good sound at the moment of impact, and that its mechanical properties, especially in terms of flight distance, are not as good as regular wood clubs. The present invention relates to a golf club wood (i.e., the head, as described above), which is made of a polymeric material and exhibits superior performance. More specifically, the present invention provides the second
The type of wood shown in the figure relates to a wood made of a particular polyurethane which, as will become clear below, has physical properties surprisingly suitable for the game of golf. In fact, the aforementioned drawbacks inherent in traditional wood or non-traditional wood have been virtually eliminated. Furthermore, it has been found that the performance of the wood molded from the cured polyurethane product of the present invention is completely unexpectedly superior to that of general wood. According to the present invention, the golf club is formed by molding hard impact-resistant polyurethane,
The polyurethane comprises (i) diisocyanates derived from aromatic diisocyanates, isomer mixtures of aromatic diisocyanates, cycloaliphatic diisocyanates, and mixtures of aromatic and cycloaliphatic diisocyanates, (ii) polyalkylene ether glycols, and optionally is made from a prepolymer obtained by reacting (iii) glycol with a molecular weight of about 350 or less according to the concentration ratio of (i) and (ii) above. Next, this prepolymer is cured to make it hard and
A hardened impact resistant polyurethane product is formed. For example, as will be apparent from the detailed description below, component (iii) is present in this prepolymer and
When all components are present at certain concentrations, the resulting prepolymer is cured by mixing with an arylene primary diamine curing agent. Component (iii) can also be a curing agent, especially if the concentrations of components (i) and (ii) are adjusted to form a prepolymer and component (iii) is omitted. The polyurethane cured product targeted here has a shore D hardness (ASTM D224) of about 50 to about 80, an elongation at break % of about 150 to about 350 (ASTM D412), and a notched Izod impact strength (ft.lb./in. .) 4 or higher (ASTM D256), Resilience% 40 or higher, generally about 40 to about 65, preferably about 43 to about 60 (ISO recommended
D.4662). Resilience% is US,
Well-known methods adopted by Vanderbilt Laboratory
Measured with a Lu¨pke impact resimeter. Other properties of the polymers of the invention are yield or recession (mm) and recovery or cancellation properties (%). These numbers are approximately 12.7mm in height,
Take a sample of the desired polymer in the form of a small cylinder with a diameter of 29 mm, and apply a pressure of 11 Kg/mm ² to the sample using a steel rod with a diameter of about 1.5 so that the semicircular end is in contact with the cylinder. It is obtained by Connect a micrometer dial to this steel rod and set the dial to zero when the hemispherical end is applied to the sample without pressure. In Table B below,
Results obtained using exemplary polymers are shown. The numbers in the first row of Table B indicate the distance the rod moved downward for each sample, i.e. the deformation, yielding, or indentation after applying rod pressure for 30 seconds; The numbers in the second row indicate the yield release (recovery) rate (%) 60 seconds after the rod pressure was removed. According to the present invention, it is desired that the yield be greater than or equal to about 0.55 mm, generally from about 0.57 to about 3.0, preferably from about 0.60 to 2.98. The recovery rate is generally about 50 to about 95, preferably about 54 to about 92. Yet another property of the elastomeric polyurethane of the present invention is determined by vibration testing. This measures the feel of impact, or the so-called shock felt when the club face hits the ball. Length 110mm, free length 100
mm, 10 mm diameter cylinders are made from the desired hardened polymer and a small 0.5 gram Endevco accelerometer is attached to the end of each cylinder. This end is then bent by 5 mm and released to allow it to vibrate freely. Table C below shows these results with amortization rates defined by logarithmic decay rates applied to the accelerometer signal recordings represented by the vibration curves of each sample. See description of Table C. The amortization rate of the elastomeric polymer used in the manufacture of Utsudo ranges from about 4.5 to about 12, preferably from about 5.0 to about 11.5
is normal. Next, the reactants for elastic polyurethane synthesis of the present invention will be explained. Typical diisocyanate components are toluene-2,4-diisocyanate (TDl), toluene-2,6-diisocyanate,
4,4'-methylene bis(phenyl isocyanate) (MDl), 4,4'-methylene-bis(cyclohexyl isocyanate), TDl and toluene-2,
An isomer mixture of 6-diisocyanate (for example, 80% of the former and 20% of the latter). Polyalkylene ether used in the present invention
Examples of glycols include polytetramethylene ether glycol (PTMEG) and polypropylene ether glycol. for example
PTMEG generally has a molecular weight of about 400 to about 3000, preferably about 600 to about 1500, and is made by polymerization of tetrahydrofuran (THF). Also,
Copolymers obtained by copolymerizing THF with about 5% to about 40%, preferably about 30%, ethylene oxide are also useful. Mixtures of these glycols may also be used. Generally, these polyalkylene ether glycols have molecular weights in the same range as the PTMEG described above. Typical glycol components having a molecular weight of less than about 350, preferably from about 62 to about 200, include 1,3-butanediol, 1,4-butanediol, ethylene glycol, diethylene glycol, trimethylene glycol, 1,2-hexylene glycol. , 1, 2-
Such as cyclohexanediol. As described above, the prepolymer is prepared by thoroughly mixing (i) a diisocyanate, (ii) a polyalkylene ether glycol, and (iii) a low molecular weight glycol component, under anhydrous conditions, at a temperature of about 25 to about 100°C, and a 0.5% ~8
It is obtained by reacting for 4 hours, preferably at a temperature of about 800°C. The molar ratio of (iii) to (ii) is approximately 0.25
~3.0, the molar ratio of (i) to (ii) + (iii) is about 1.5-2.0. It is also optional to carry out the mixing step in two or more stages. The prepolymer thus obtained is in a liquid state, and when it is then cured, a solid polyurethane cured product is obtained. Typical curing agents for these prepolymers include arylene primary diamines, such as 4,4'-methylenebis(2-chloroaniline), 4,4'-methylenebis(2-carbomethoxyaniline), 4,
4'-diaminodiphenyl disulfide, 4,4'-
diaminodiphenylsulfone, mixtures thereof, and the like. It is clear that an arylene amine is one in which each of the two primary amino groups is directly bonded to another arylene group. Also, methylene dianilylene can be prepared in water or its solvent.
Complexes obtained by intimate mixing with NaCl can also be used as hardeners. Generally, this complex has a methylenedianiline component of about 3
It is obtained by mixing 1 mole of salt component with 1 mole of common salt component. Curing of the three-component prepolymer is best accomplished by mixing the liquid prepolymer with a curing agent at a temperature of about 25°C to about 135°C, preferably about 100°C. Generally, a curing time of 3 hours is preferred, but periods from about 1 to about 24 hours are also effective, depending on the temperature used.
Higher temperatures accelerate curing. with a stoichiometrically sufficient amount of curing agent present;
~50~ of free isocyanate groups in the prepolymer
It is necessary to react with approximately 110%. The following examples are illustrative and do not limit the scope of the invention. Example 1 1 mole of polytetramethylene ether glycol (PTMEG) having a molecular weight of 1000, 1 mole of 1,3-butanediol (BDO), and 4 moles of toluene-2,4-diisocyanate (TDl) were prepared under substantially anhydrous conditions. Mix at 80℃ for 4 hours to create a stable liquid prepolymer. The obtained prepolymer (100
100°C) and 30 parts of 4,4′methylenebis(2-chloroaniline) (120°C),
A common mold (100
Preheat to ℃). The Wilson×31 is an extremely high quality golf club model manufactured by the Wilson Sporting Goods Company in the United States. Next, heat this mold in an oven at 100℃ for 3 hours,
Cool the mold and remove the molded club head. This is, of course, in the shape of the Wilson x 31 mentioned above. The weight of the molded article is adjusted to the weight of the driver including the insert shown in FIG. 1, 205 g, by sanding at position 29 in FIG. 2 to match the weight of the commercially available wood. The exact same shaft used in commercially available screwdrivers is attached to this molded head, and the total weight of the commercially available screwdriver is 370.
g, match the swing weight of 20.6. Example 2 Example 1 is repeated except that the molar ratios of the prepolymer composition are as follows and 23 parts of 4,4'-methylenebis(2-chloroaniline) are used. PTMEG 1.0 mol BDO (1,3-butanediol) 0.33 mol TDl 2.67 mol Example 3 12 parts of 4,4'-methylenebis(cyclohexyl isocyanate) was mixed with 88 parts of prepolymer and then cured. , repeat Example 1. Generally, for 95 to 70 parts of prepolymer,
5 to 30 parts (by weight) of cycloaliphatic diisocyanate are used. The prepolymer is made similarly to Example 1 above. The resulting cycloalkylisocyanate-treated prepolymer is reacted with an approximately chemical equivalent of 4,4'-methylenebis(2-chloroaniline) curing agent, i.e., the free isocyanate groups in the prepolymer so treated. Cure with sufficient amount of curing agent. Example 4 One mole of PTMEG having a molecular weight of 650 is reacted with 5 moles of 4,4'-methylene bis(phenylisocyanate) for 3.5 hours at 110 DEG C. under substantially anhydrous conditions.
Next, the obtained liquid prepolymer is cured with 1,4-butanediol (BDO) at 95°C for 5 hours. At this time, BDO is thoroughly mixed with the prepolymer, and BDO accounts for approximately 95% of the chemical equivalent of BDO based on the free isocyanate groups in the prepolymer.
present in sufficient quantities to give Generally, prepolymers are made using 3 to 6 moles of diisocyanate per mole of glycol and cured with low molecular weight glycols present at a concentration of 95% to 100% relative to the isocyanate groups. Curing temperature is 90~
The temperature is 120℃. Of course, to make the wood of Example 1, curing takes place in a mold. Shore D
Hardness is 70. Example 5 Example 4 is repeated except that bis(beta-hydroxy ether) of hydroquinone is used as the curing agent. The properties of the hard, impact-resistant cured polyurethane obtained in the above examples are shown in the following table. The measurement method was as described above.

[Table] was also not destroyed.

【table】

[Table] δ
α＝

Claims (1)

[Scope of Claims] 1. A polyurethane cured golf club head having a single body that is solidly molded and includes the entire front hitting surface, the cured polyurethane being a cured prepolymer. , the prepolymer comprises component (i), a diisocyanate selected from aromatic diisocyanates, isomer mixtures of aromatic diisocyanates, cycloaliphatic diisocyanates, and mixtures of aromatic diisocyanates and cycloaliphatic diisocyanates, and component (ii) and a low molecular weight glycol having a molecular weight of 350 or less as component (iii), the curing agent is an arylene primary diamine, and the molar ratio of components (iii) to (ii) is 0.25 to 3.0, and the molar ratio of component (i) to component (ii) + component (iii) is 1.5 to 2.0, and the stoichiometric concentration of the curing agent is such that the free isocyanate in the prepolymer is Base 50-110
%, and the cured polyurethane has a Shore D hardness in the range of 50 to 80, a % elongation at break of 150 to 350%,
Notched isot impact strength of 4 (ft. lb./in.) or higher, % resilience of 40% or higher, indentation properties of 0.55 mm or higher, % recovery of 50-95%, and 4.5-12%
A molded polyurethane cured golf club head, characterized in that it exhibits amortization characteristics of %. 2 Indentation characteristics in the range of 0.57-3.0mm, 54-92%
The golf club head of claim 1 having a recovery percentage of 5.0 to 11.5% and a depreciation percentage of 5.0 to 11.5%. 3. The polyurethane cured product is a cured prepolymer, and the prepolymer contains a reaction product of 3 to 6 moles of 4,4'-methylenebis(phenylisocyanate) and 1 mole of polyalkylene ether glycol, The curing agent is selected from low molecular weight glycols with a molecular weight of 350 or less, and the curing agent is 95% to 95% of the free isocyanate groups in the prepolymer.
A golf club head according to claim 1, wherein the golf club head is present at a stoichiometric concentration of 100%. 4. The golf club head of claim 2 having an indentation characteristic in the range of 0.60 to 2.98. 5 component (ii) has a molecular weight in the range of 400 to 3000,
A golf club head according to claim 1, wherein component (iii) has a molecular weight in the range of 62-200. 6 Component (i) is toluene-2,4-diisocyanate (TDI), component (ii) is polytetramethylene ether glycol (PTMEG), and the component
2. A golf club head according to claim 1, wherein (iii) is 1,3-butanediol and the curing agent is 4,4'-methylenebis(2-chloroaniline). 7 In addition to components (i) to (iii), 5 to 30 parts by weight of an alicyclic diisocyanate is present in the prepolymer based on 95 to 70 parts by weight of components (i) to (iii). A golf club head according to claim 1. 8. The golf club head of claim 7, wherein the additional component is 4,4'-methylenebis(cyclohexyl isocyanate).