JPS6118466B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial field to which the invention is applied The present invention relates to a wooden sphere similar to a wooden sphere carved from wood. Accordingly, the present invention is in the field of industry that manufactures, sells and uses wooden spheres such as gateballs and displays them for sale and use.

BACKGROUND OF THE INVENTION Wooden spheres are widely used for games such as Ken balls and balls for gateball games. However, wooden spheres carved from natural wood have a large amount of wear and tear, and various substitute spheres have been developed.

For example, the balls used in gateball games, which have recently become popular, were originally made of wood carved from wood, but they often cracked or chipped from the wood grain due to hits from sticks or collisions between balls. The drawback was that it became unusable. For this reason, balls made of plastic, which are less likely to break, have become mainstream.

However, plastic balls generally have low surface hardness and have the disadvantage of being easily soiled. Furthermore, when hitting with a stake, there was a fundamental drawback in that the sound, feel, and maneuverability of the hit were quite different from those of a wooden ball.

As a way to overcome the drawbacks of plastic balls, a ball made of wood flour as a base material and a thermosetting resin as a binder was devised. However, such a ball had a specific gravity of more than 1.2 and was not very similar to a wooden sphere. Another drawback was that in order to manufacture large balls such as gate balls with a diameter of 75 mm, the thermosetting resin had to be sufficiently cured to the center, which required a long processing time.

An example of a prior art technique that is very close to the present invention is that described in Japanese Patent Application Laid-open No. 54970/1983. The gist of this prior art is as follows: 1. It is obtained by compression molding a molding material containing a thermosetting resin, cloth strips or thread waste, and a porous filler, and has a specific gravity of 0.95 to 1.10. A gate ball made of thermosetting resin.

2 The thermosetting resin solution is made up of 10 to 40% of the total resin component.
% by weight, add porous filler and cloth strips or thread waste, dry and condense in a high-speed stirring mixer to obtain a molding material, and then mold it. A unique method for manufacturing thermosetting resin gate balls.

It is.

Problems with the Prior Art In this prior art, a suitable amount of cloth strips or yarn waste is used, but according to the inventor's opinion, the specific gravity of this type of fibrous material varies greatly depending on the degree of compression, so the weight percentage Uniquely and easily,
When looking at a large number of products where it is difficult to determine the contamination rate,
This is a problem because the specific gravity of the ball fluctuates greatly. In addition, the volume is large relative to its specific gravity, making it difficult to mix it so that it is evenly distributed throughout the ball.

Furthermore, in the above-mentioned prior art, as the porous filler to be mixed, Shirasu balloon, 4
-40 meshes of wood flour, 4-30 meshes of cork powder, and 18-20 meshes of powder of thermosetting foam resin, such as foamed phenolic resin, are distributed either alone or in combination.

However, according to the inventor's opinion, the Shirasu balloon is not only quite expensive, but also has the disadvantage that it is far from a wood-like feeling because it is an inorganic substance. Also, 4 to 40
When using the same weight of Metsushi wood flour, finer grain size is better because it has a larger volume, but this grain size range is too coarse and it takes away from the true wood texture, and the surface is polished to a glossy finish. I'm jealous that I can't get a face. The same can be said for cork powder of 4 to 30 mesh. And the price is also extremely high.

Also, what about 18 to 20 mesh powder of thermosetting foamed resin such as foamed phenolic resin, which has the disadvantage that the light weight of the cut angle destroys the cellular structure and reduces the voids. There is.

Means of the present invention for solving the problems of the prior art In the present invention, in order to eliminate the drawbacks of the prior art described above, a wooden sphere having the following configuration is proposed.

That is, 50 to 10 parts by weight of thermoplastic resin, 60 to
It contains 50 to 90 parts by weight of wood flour having a particle size of 100 mesh and a blowing agent of 1 to 10% by weight of the total amount of both, and has a large amount of artificially generated air bubbles, and has a specific gravity. A wooden sphere is proposed, which is characterized in that the is between 0.9 and 1.0. Of course, there is no problem in adding a small amount of pigment as appropriate according to a conventional method.

Therefore, most of the porous fillers in the prior art described above do not use this material, but only wood flour that passes through a particularly fine mesh is used and is obtained by intimately mixing with resin and other mixed materials. Achieving beautification of the surface structure of objects.

Effects of the invention The core points of the new technology of the present invention are:
In products that produce wooden spheres by mixing and heating a thermosetting resin and wood flour, an appropriate amount of foaming agent is added to artificially generate and contain a large amount of air bubbles, and the pressure of the generated gas causes the inside to blow. The molded product is pressed onto the inner surface of the mold by the pressure generated from the mold, thereby obtaining a beautiful product surface and a wooden sphere whose composition becomes harder from the inside toward the outer layer.

In addition, there is no need to use expensive and non-wood porous fillers such as whitebait balloons, cork powder, and thermosetting foam resin powder such as foamed phenolic resin, and even wood powder can be used with 4 to 40 mesh. Since we use fine powder of 60 to 100 mesh instead of coarse particles like those used in the above, it is homogeneous as a whole, and is compatible with other wooden hammers, resulting in a product that is extremely similar to wood.

EXAMPLES Below, a few numerical method examples are given to provide a better understanding of the invention, but before doing so, a general overview of the invention is desired.

In the present invention, the thermosetting resin as a binder added in 50 to 10 parts by weight may be any resin that can be cured by heating, and general resins such as phenol resins, urea resins, and unsaturated polyester resins can be used. For example, as phenolic resins, not only resol resins that cure by heat alone, but also novolac resins can be used by adding the curing agent hexamethylenetetramine, and even compounded and molded as molding materials.
Even kneaded or ground products can be used. If the amount of binder added is less than 10 parts by weight, it will be difficult to obtain a molded product.
If it weighs more than 50 parts, the product will be too hard and it will be difficult to produce a sound similar to that of a wooden hammer.

The amount of blowing agent added is 1 to 10% by weight of the total amount of wood flour and thermosetting resin, preferably 3 to 7%, but 1%.
This is because if the specific gravity is less than 10%, the specific gravity will be high, and if it is less than 10%, the manufacturing cost will increase and the effect will be small.

Further, the wood flour used in the present invention has a particle size of 60
~100 mesh (here mesh is the grain size name in the wood flour market) Among these, slightly coarser grains are preferable, and if the particle size is smaller than 100 mesh, a large amount of thermosetting resin is required and the woody feel becomes It fades. On the other hand, if you use wood flour coarser than 60 mesh, the mixing and dispersion will be uneven and the density will likely be uneven. Also, if there is too much wood flour, there will be insufficient thermosetting resin as a binder and the material will not have sufficient strength, while if there is too little wood flour, it will have a strong plastic feel and will not have the feel of wood.

In addition, as the above-mentioned foaming agent, one must be used that decomposes at a temperature below the molding temperature of the thermosetting resin used as a binder, but azobisisobutynitrile, benzenesulfonylhydrazide, etc. It is preferable that the temperature is 100 to 200°C.

For molding, wood flour, thermosetting resin, and foaming agent are thoroughly mixed, the required weight is measured based on the volume of the sphere to be molded and the desired specific gravity, and preforming is performed at room temperature. When the preform is preheated and charged into a heated mold, and the mold is closed and heated, the preform will soften and flow from the part in contact with the mold, decompose the blowing agent, and thermoset resin. As the hardening progresses, woody spheres with uniformly dispersed air bubbles are formed.

As described above, in the present invention, the specific gravity of the entire sphere is 0.9~
Since the main constituent material is wood flour with a particle size of 1.0 and 60 to 100 mesh, it has properties very similar to wooden spheres, but also has the disadvantages of wooden spheres, such as being easy to break from the wood grain. do not have. The molding process is very efficient as it hardens uniformly up to the center in a short time.

Production Example 1 140 g of 60 mesh wood flour, 60 g of urea resin, and 10 g of blowing agent were mixed, preformed into a size of 33φ x 200, placed in a 75 mm diameter mold that had been preheated to 180° C., and charged and heat molded.

The average specific gravity of the obtained ball is 0.9, the specific gravity of the parting part (where resin flows out at the joint of the mold and increases the specific gravity) is 0.92, and the other specific gravity is 0.89, making it a gateball ball with almost uniform specific gravity. If a burr is obtained, of course it will be removed.

Manufacturing Example 2 100 mesh wood flour 150 g, phenolic resin 60 g, and blowing agent 6.3 g were mixed, preformed into a size of 35φ x 170, preheated, and then molded in the same manner as in Example 1 at a mold temperature of 175°C.

The obtained ball had an average specific gravity of 0.95, a specific gravity of the parting part of 0.96, and a specific gravity of the other parts of 0.95, so that a ball with a substantially uniform specific gravity was obtained. If burrs appear, of course they must be removed.

Claims (1)

[Claims] 1 Contains 50 to 10 parts by weight of a thermosetting resin, 50 to 90 parts by weight of wood flour having a particle size of 60 to 100 mesh, and a blowing agent of 1 to 10% by weight of the total amount of both, and A wooden sphere characterized by having a large amount of naturally generated air bubbles and having a specific gravity of 0.9 to 1.0.