JP2003320057A - Tennis ball, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and efficiently manufacture a tennis ball at a low cost without using a melton. <P>SOLUTION: An adhesive is applied on an outer surface of a core 2, fibers 3 are flocked by electrostatic filling to form a fiber layer 4, and the tennis ball 1 is manufactured thereby. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tennis ball and a method for manufacturing the same, and more particularly to a hard tennis ball having a fiber layer formed by flocking on the outer surface of a core, and a method for manufacturing this tennis ball.

[0002]

2. Description of the Related Art A tennis ball is constructed by forming a thick woven felt called a melton on the outer surface of a hollow spherical body called a core having rubber elasticity. Melton used to coat the core is, for example, wool and nylon, polyester, rayon, and other mixed yarns, cotton yarn is used for the back yarn, satin weave, and after pulling out a large amount of fluff, raising wool. The fiber structure is tightly entangled and densely hardened by the unique process of fibrillation, and the finished product is felt-like.

Melton has a large thickness of about 2.8 to 3.6 mm, which is completely different from general woven fabrics.
The manufacturing process is also special and complicated.

In order to manufacture a tennis ball using such a melton, first, the entire back surface of the melton is glued, dried, and then punched into a dumbbell shape for bonding to the core. Meltons punched into this dumbbell mold are once packed, coated with joint rubber on the edges, dried, and then peeled one by one, and attached to a core coated with glue in another step. After that, press vulcanization is performed to vulcanize and bond the melton, the core, and the joint, and finally, the product is obtained by brushing with steam and then drying.

The manufacturing process of this tennis ball is almost the same regardless of the kind of melton, that is, woven or non-woven.

[0006]

[Problems to be Solved by the Invention]
When punched into a dumbbell-shaped shape for sticking to the core, the remaining punched-out irregularly-shaped end pieces cannot be used and will be discarded. Since the melton is coated with the paste before punching, not only the melton but also the back paste is discarded, and there is much waste of the melton and the paste, which causes an increase in manufacturing cost. Moreover, many steps are required to attach the melton to the core, which also increases the cost of the tennis ball.

Further, it is difficult to change the design because it is manufactured by a limited number of melton makers.

The present invention has been made in view of the above conventional circumstances, and an object thereof is to provide a hard tennis ball which can be easily and efficiently manufactured at low cost without using a melton. To do.

[0009]

The tennis ball of the present invention is characterized in that a fiber layer by flocking is formed on the outer surface of the core.

The method for producing a tennis ball of the present invention is characterized by including a step of forming a fiber layer by flocking on the outer surface of the core or the half shell for producing the core.

By implanting fibers directly into the core, a tennis ball can be manufactured by a simple process without using an expensive melton.

The formation of the fiber layer by the flocking can be easily carried out. By adjusting the kind of the fibers to be flocked and the flocking density, etc., not only the performance of the tennis ball is improved, but also a new type which has never existed before It will also be possible to develop tennis balls.

In the present invention, the fiber layer is preferably formed by applying an adhesive to the outer surface of the core or half shell and then electrostatically implanting the fibers.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view of a surface portion showing an embodiment of a tennis ball of the present invention.

In this tennis ball 1, fibers (pile) 3 are planted on the surface of a rubber hollow spherical core 2 to form a fiber layer 4.
Is formed.

The method of flocking is not particularly limited, but there is a method of applying flocking by electrostatic flocking after applying an adhesive to the outer surface of the core 2.

The core 2 may be made of a rubber sphere generally used conventionally.

The fibers forming the fiber layer 4 include, but are not limited to, polyamide fibers, polyester fibers, polyolefin fibers, natural fibers such as cotton and wool, and the like. These fibers may be used alone or in combination of two or more.
When two or more kinds of fibers are used in combination, a pile obtained by mixing two or more kinds of fibers may be used, or two or more kinds of piles may be used in combination.

The length of the fibers is preferably 5 mm or more, but if the fibers are excessively long, it is necessary to adjust the appearance after hair transplantation. Therefore, it is preferably 20 mm or less, preferably 10 mm or less. .

The aspect ratio and fineness (denier) of the fiber are not particularly limited, and the thickness, weight and bounce characteristics of the fiber layer 4 are adjusted according to the product standard of the tennis ball depending on the type of fiber used and the flock density. It is sufficient that the amount of deformation and the like can be adjusted within a required range.

That is, for example, the weight of a standard ball of the tennis ball standard is 56.0 to 59.4 g, and the diameter is usually in the range of 6.54 to 6.86 cm. On the other hand, the core has a diameter of 42 to 48 g and a diameter of 5.7 to 6.2 cm.
Since it is molded to a certain extent, it is 3 to 8 mm thick and weighs 10 to 1
The length of fiber used, aspect ratio and fineness, and flocking at the time of flocking so that the fiber layer 4 of about 5 g is formed and the bounce characteristics, forward deformation amount and return deformation amount of the tennis ball standard are satisfied. It is preferable to adjust the density appropriately. The core weight is not limited to the above, and it can be adjusted to be optimum in balance with the fiber weight.

The color of the fiber is white or yellow if it is an official sphere, but there is no particular limitation if it is not an official sphere.

Generally, as the fiber, polyamide fiber,
It is preferable to use polyester fibers, polyolefin fibers, cotton, wool, etc., and it is preferable to use a pile having a length of 5 to 20 mm and to implant hair at a density of about 10 to 15 g / sphere. However, as long as it is a practice tennis ball that is not a standard tennis ball standard, it is not limited to the above range, and various types of tennis balls can be obtained with a wide degree of freedom in design.

The adhesive applied to the outer surface of the core is not particularly limited, and it is not a curable adhesive as long as it can follow the deformation of the rubber core after adhering the fibers.
Specifically, solvent-based or water-based adhesives such as acrylic, urethane, and rubber adhesives can be used. In the case of a solvent-based adhesive, it may be a one-component type or a two-component type.

Specifically, the fibers may be transplanted to the core as follows. First, an adhesive is applied to the outer surface of the core. The adhesive may be applied by any of a spray method, a dipping method, a brush coating method, and the subsequent method. When forming the joints on the tennis ball, the joints are masked in advance when the adhesive is applied. The application amount of the adhesive is not particularly limited, but in the usual case, it is preferably about 1 to 2 g / sphere.

It is preferable to buff the outer surface of the core before applying the adhesive.

After applying the adhesive to the outer surface of the core in this way, fibers are planted by electrostatic flocking or the like. This electrostatic flocking method is performed by a normal method, that is, an up method for flying fibers, a down method for dropping fibers, an up-down method in which these are combined, and the like.

After flocking in this way, after vulcanization as needed, brushing with steam is applied, and if necessary, appearance adjustments such as fiber cutting and permanent processing are performed to obtain the product. To do.

Further, when forming the joint, the joint rubber is put in the non-flocked portion of the joint, and then the joint rubber is vulcanized and adhered by press vulcanization or the like.

In the above description, the case of implanting hair on the core previously formed into a hollow spherical shape has been described, but the present invention is not limited to this, and the hair is implanted in the state of the half shell before forming the hollow spherical shape. Is also good.

That is, for the core, a rubber block (plug) is heated and pressed by a press machine to form a hemispherical half shell, and an adhesive is applied to the adhesive surface of the half shell to form two half shells. It is manufactured by pasting together, heating with a press, pressurizing and integrating, but in the present invention,
The hollow spherical core thus manufactured may be flocked, or the hemispherical half shell before bonding may be flocked. When flocking is performed on the half shell, an adhesive may be applied to the outer surface of the half shell in the same manner as described above, flocking may be performed, and then the pieces may be bonded and integrated, and then raised.

The tennis ball manufactured in this manner has a slightly different appearance from the conventional tennis ball coated with the melton because the surface fiber layer is formed by flocking, but the hit feeling is similar to that of the conventional tennis ball. , You can get the flight distance.

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following examples.

Example 1 A tennis ball was manufactured by implanting hair on a hollow spherical core.

After buffing the outer surface of a rubber core having a weight of 50 g and a diameter of 61 mm and masking the joint-corresponding part, about 1 g / sphere of a natural rubber latex adhesive was applied. Then a pile made of nylon fiber (length 5 mm)
About 7 g was electrostatically flocked. After the flocking, a thread-shaped unvulcanized joint rubber was fitted into the masking portion and press-vulcanized.
At the time of this vulcanization, the adhesive for flocking is also vulcanized. Then, the product was obtained by brushing with steam.

The tennis ball obtained had a fiber layer having a thickness of 4 mm and a weight of about 7 g formed on the outer surface of the core, and the total weight thereof was 58 g and the diameter was 6.5 cm.

This tennis ball was tried by five hitters and was compared and evaluated with a conventional product having the same weight and diameter (a tennis ball covered with a melton). It was possible to obtain a result equivalent to that, and it was possible to obtain an evaluation that the hit feeling was almost the same as that of the conventional product.

Example 2 A tennis ball was produced by implanting hair in a half shell before being laminated to form a core.

After buffing the outer surface of a half shell (weight: 23 g) for producing a hollow spherical core having a diameter of 60 mm, a natural rubber latex adhesive was applied at about 0.5 g / half shell. Then, about 3.5 g / half shell of a pile (length 5 mm) composed of polyamide fiber and acrylic fiber was electrostatically flocked. After flocking, a rubber-based adhesive was applied to the adhesive surface of the half shell, and then a chemical for applying an internal pressure was injected, and the two half shells were bonded together and vulcanized by a press machine to be integrated. At the time of this vulcanization, the adhesive for flocking is also vulcanized. Then, the product was obtained by brushing with steam.

The obtained tennis ball was a jointless one in which a fiber layer having a thickness of 4 mm and a weight of about 7 g was formed on the outer surface of the core, and the total weight was 58 g and the diameter was 6.5 c.
It was m.

This tennis ball was hit by five trial hitters in the same manner as in Example 1, and a comparative evaluation with a conventional product (tennis ball covered with melton) having the same weight and diameter was carried out. It was possible to obtain the same results as in the conventional product in terms of rebound and the like, and it was possible to obtain an evaluation that the hit feeling was almost the same as that of the conventional product.

[0043]

As described in detail above, according to the present invention, by forming a fiber layer on the outer surface of the core by flocking,
A hard tennis ball can be easily and efficiently manufactured without using an expensive melton.

Therefore, the tennis ball can be manufactured at a lower cost as compared with the case where the melton is used, and the problem of waste of the end portion caused by punching the melton is solved.

Moreover, the fiber layer can be easily formed by flocking, and the degree of freedom in developing the tennis ball can be increased.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a surface portion of a tennis ball according to an embodiment.

[Explanation of symbols]

1 tennis ball 2 cores 3 fibers 4 fiber layers

Claims (3)

[Claims] 1. A tennis ball having a fiber layer formed by flocking on the outer surface of a core. 2. A method for producing a tennis ball, comprising the step of forming a fiber layer by flocking on the outer surface of the core or a half shell for producing the core. 3. The method of manufacturing a tennis ball according to claim 2, wherein the fiber layer is formed by applying an adhesive to the outer surface of the core or the half shell and then electrostatically flocking the fiber layer.