JPH11226859A - Resin chip for grinding metal lump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the wear and breakage of resin chip during grinding, prevent it from becoming dirty, wash off dirt of a metal lump sufficiently, and improve its luster markedly by forming it by resin containing metal soap. SOLUTION: This resin contains metal soap. Consequently, dirt of a metal lump can be washed off sufficiently, its luster can be improved markedly, and the wear and breakage of resin chip can be reduced. The metal soap used here indicates metal salts other than alkali metal such as fatty acid, resin acid, naphthenic acid, etc., and includes metal salts, for example, such as magnesium, calcium, manganese, aluminum, cobalt, zinc, nickel, etc.. Polyamide resin is preferable as the resin used here because it excels in the resistance against wear, has high toughness, and is hardly broken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin chip for polishing suitably used for improving the lubrication and luster of a metal lump, particularly a pachinko ball, and to a method for polishing a metal lump using the same. .

[0002]

2. Description of the Related Art Conventionally, a metal lump such as a pachinko ball becomes dirty or rusted with hand grit or sweat when used, and loses its luster. It was a big problem with pachinko balls.

[0003] In order to solve such a problem, conventionally, metal lump is made of polyethylene, polypropylene, polyester,
A method of polishing with a mixture of resin chips such as polyamide has been adopted.However, the resin chips are worn or damaged and cannot be used for a long time, and the luster of metal blocks is not sufficiently improved. there were. Furthermore, there is a problem that the resin chips used are easily stained and must be washed frequently.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has as its object that it is hard to be worn or damaged during polishing, and it is hard to get dirty. It is an object of the present invention to provide a metal lump polishing resin chip capable of remarkably improving the performance.

[0005]

According to the study of the present inventors, the object of the present invention is to provide a metal lump polishing resin chip characterized by comprising a resin containing a metal soap and a resin chip for polishing a metal lump. It has been found that this can be achieved by the metal lump polishing method used.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The resin used in the present invention may be any resin such as polyamide resin, polyester resin, polycarbonate resin, polyolefin resin, poly (meth) acrylate resin, polyurethane resin and polyimide resin. Resins may be mentioned, and these resins may be used in combination of two or more kinds. Among these, polyamide resins are preferred from the viewpoint of excellent wear resistance, high toughness, and difficulty in breaking, and examples thereof include nylon 6, nylon 66, nylon 4-10, nylon 4, and the like, and mixtures and copolymers thereof. can do. In particular, nylon 6 or nylon 66 is widely used and easily available, and nylon 6 is excellent in that it is flexible and has excellent polishing properties for metal lump.

[0007] The higher the degree of polymerization of the resin, the less damage during polishing is preferable. For example, in the case of nylon 6,
The intrinsic viscosity measured at 35 ° C. in m-cresol solvent is 1.
A range of 0 to 2.0, particularly a range of 1.3 to 1.8 is suitable.

In the present invention, it is essential that the above-mentioned resin contains a metal soap. By doing so, it is possible to sufficiently remove dirt from the metal lump and remarkably improve the gloss. Wear and breakage of the resin chip can be reduced. The metal soap used herein refers to metal salts other than alkali metal salts such as fatty acids, resin acids, and naphthenic acids, and examples thereof include metal salts such as magnesium, calcium, manganese, aluminum, cobalt, zinc, and nickel. it can. Of these, alkaline earth metal salts of higher fatty acids having 16 to 22 carbon atoms, such as magnesium and calcium, are preferable, and calcium stearate or magnesium stearate is particularly preferable.

If the content of the metal soap in the resin is too small, the degree of improvement in the gloss of the surface of the metal lump by polishing becomes small, so that the metal content in the resin is 10 p.
pm or more, particularly in the range of 50 to 500 ppm is suitable.

The shape of the chip made of the resin containing the metal soap does not need to be particularly limited, and may be appropriately selected and set according to the metal lump to be polished. For example, when the metal lump is a pachinko ball, And a particle having a diameter of 1.0 to 10 mm, particularly 1.5 to 4.0 mm is preferred.

When the metal lump is polished using the metal lump polishing resin chip of the present invention described above, it is not necessary that all the resin chips contain metal soap. The metal-soap-containing chip and the non-metal-soap chip may be mixed so that the metal content based on the weight of the resin chip to be obtained is about 50 to 500 ppm. That is, a high-concentration chip containing several percent to several tens of percent of metal soap may be mixed with a few percent of resin chip containing no metal soap and used, for example, nylon 6 containing 10% of calcium stearate. The chips may be mixed at 1% with nylon 6 chips that do not contain metal soap.

[0012]

The present invention will be described in more detail with reference to the following examples. In addition, each evaluation item in an Example followed the following method.

<Gloss of Pachinko Ball> The polished pachinko ball was evaluated according to the following criteria by sensory evaluation by five panelists. Good: State of gloss and gloss close to that of a new article Poor: State of insufficient gloss and gloss and dull appearance

<Resistance to wear of resin> Resin chip 10 kg
And 5 kg of pachinko balls were placed in a rotary tumbler, stirred at a rotation speed of 30 rpm, and evaluated based on the following criteria from the loss of resin chip abrasion after 48 hours. Good: Loss on wear ≦ 1.0% Poor: Loss on wear> 1.0%

<Resin Dirt> 15 kg of resin chips are put into the passage reservoir of the pachinko balls sent from the pachinko machine, and the resin chips and the pachinko balls are mixed and conveyed by an air flow to polish the pachinko balls. And the pachinko balls were separated, and when the separated resin chips were circulated through the passage reservoir and reused, stains on the surface of the resin chips after three days were visually determined by five panelists. Good: State of luster and luster close to that of a new article Poor: State in which the resin surface is darkened by metal powder or dirt

<Washing cycle> When polished under the same conditions as above,
The number of days in which the resin chip became dirty and darkened and required washing was expressed.

[Examples 1 to 7, Comparative Examples 1 and 2] As shown in Table 1, a resin and a metal soap were melt-mixed and extruded from a discharge hole to prepare a resin chip having an average particle diameter of 2.0 mm.
The amount of metal soap added indicates the weight of metal ions in the resin in ppm. Nylon 6 has an intrinsic viscosity of 1.
34 were used. Table 1 shows the evaluation results of the obtained resin chips.

[0018]

[Table 1]

[0019]

The metal-polishing resin chip containing the metal soap according to the present invention, when used for polishing a pachinko ball, for example, can easily remove dirt from the pachinko ball and significantly improve the luster and gloss of the ball. It will be as good as new. Also,
Since the resin chip itself is hardly soiled, the washing cycle of the resin chip can be significantly lengthened. Further, when a polyamide resin, particularly nylon 6 or nylon 66, is used as the resin, it is possible to further improve the wear durability and the washing cycle particularly.

Claims (6)

[Claims] 1. A resin chip for polishing a metal lump, comprising a resin containing a metal soap. 2. The resin chip for metal lump polishing according to claim 1, wherein the metal soap is magnesium stearate or calcium stearate. 3. The resin chip for metal lump polishing according to claim 1, wherein the resin is a polyamide resin. 4. The metal lump polishing resin chip according to claim 3, wherein the polyamide resin is nylon 6 or nylon 66. 5. A resin chip for polishing a pachinko ball, comprising the resin chip according to any one of claims 1 to 4. 6. A method for polishing a metal lump, wherein the surface of the metal lump is polished by using the resin chip according to claim 1.