JPH0631000B2 - Eraser with abrasive - Google Patents

Description

TECHNICAL FIELD The present invention relates to an eraser containing an abrasive, and in particular, an image formed on a paper surface by an electrostatic copying method, a handwriting with an oil-based ballpoint pen using a highly viscous ink, and the like. The present invention relates to an eraser containing an abrasive, which is suitable for erasing a handwritten image in which the ink does not penetrate the fibers of the paper.

(Prior art and its problems) Generally, the surface of paper has unevenness due to the overlapping of paper fibers, and toner or ink such as an image by electrostatic copying or handwriting with an oil-based ballpoint pen is the paper fiber itself. Although it did not penetrate into the paper, it could not be completely erased with an ordinary pencil eraser because it entered into the concave part of the paper surface and was fixed.

Therefore, conventionally, in order to erase these images and handwriting, a method of mainly scraping off the portion to be erased with a blade of a cutter knife and a method of erasing the portion with an eraser containing an abrasive material called a sand eraser have been adopted. However, according to these methods, it is troublesome, and the fibers on the surface of the paper are peeled off to damage the surface of the paper, resulting in a poor appearance, and other problems such as making rewriting impossible. Was caused.

In order to solve these problems, the present inventors focused their attention on the abrasive in the eraser containing the abrasive, and after conducting various studies on this, used an abrasive having a relatively large average particle diameter. In this case, since the load applied to each abrasive material itself is sufficient, it is good in terms of erasability, but on the contrary, there is a problem in terms of stain resistance on the paper surface. When the material is used, the erasability is inferior because the load applied to each abrasive itself becomes insufficient,
On the other hand, we have come to the conclusion of one of the magnitude relationships in the abrasives that there is no problem in terms of stain resistance on the paper surface.

(Means for Solving Problems) The present invention has been made on the basis of the above findings. An abrasive powder having an average particle diameter smaller than that of the resin powder is fixedly arranged on the surface of the resin powder as a core. By using an abrasive having an apparently large average particle size and incorporating the abrasive in a known eraser, the abrasive has only the advantages when the abrasive is relatively large and when it is relatively small. It has succeeded in obtaining an eraser containing an abrasive material.

That is, the gist of the present invention is an eraser containing an abrasive material, which comprises an abrasive material in which abrasive powder having an average particle size smaller than that of the core is fixedly arranged on the surface of the core made of resin powder. Is.

Generally, when an abrasive having a large particle diameter is used, the force applied to the paper surface per abrasive is large and deep, and therefore, the erasing power is large and the time until erasing is short, but on the other hand, It has the disadvantage of damaging and soiling the fibers of the paper. In addition, when using an abrasive with a small particle size, since the portion to be polished at one time is small, the amount of polishing is small and it is difficult to damage the paper surface, but it needs to be rubbed many times, It has the disadvantage of taking a long time. In the present invention, in particular, as the abrasive, one in which abrasive powder having an average particle diameter smaller than that of the nucleus is fixedly arranged on the surface of the core made of resin powder is used, and since the apparent particle diameter of the abrasive is large, The force applied to the paper surface of each material is large and deep. However, the abrasive of the present invention does not act to peel off the paper fiber because the hard part having abrasive power has a small particle size. Therefore, it is possible to completely scrape off the toner and ink that have entered the recesses on the surface of the paper by applying sufficient load to the abrasive.
Along with this, the polishing powder, which is a hard part having a polishing effect, is a relatively small part when viewed from the whole abrasive,
It is possible to prevent damage to the paper surface during erasing and rubbing as much as possible, and there is no possibility of rewriting on the area.

Hereinafter, the present invention will be described in detail.

The resin powder, which is the core of the abrasive of the present invention, has the purpose of shaving off the toner and ink that have entered into the fine recesses on the paper surface, so the average particle size is 50 to 150 μm.
m, preferably 70 to 130 μm. Basically, any material may be used as long as it is softer than the polishing powder described later, and synthetic resin such as nylon, polyethylene, acrylic, polyvinyl chloride or copolymers thereof, or natural resin such as starch or gum arabic. Etc.

The average particle size of the abrasive powder fixedly arranged on the surface of the resin powder, which is the core, specifically, the driven powder, is preferably about 1/20 to 1/5 of that of the resin powder. The reason is that if the polishing powder is too small, the polishing effect will be weakened and it will be difficult to erase the handwriting, images, etc. If the polishing powder is too large, it will be difficult to fix it to the resin powder, or the number will be significantly reduced. This makes it difficult to obtain the desired polishing effect. Examples of the material of the polishing powder include materials conventionally known as polishing materials, and specifically include glass powder, carborundum, silica sand and the like.

The weight ratio of the resin powder as the core in the polishing material in the present invention to the polishing powder is slightly different depending on the particle size ratio of the one used and the specific gravity of each, but generally the ratio of the polishing powder to the resin powder is 0.5 to 2.0. Set to.

In addition, the usage ratio of this abrasive to the entire eraser is
20-35% by weight, more preferably 25-30% by weight
However, it is appropriate in consideration of the moldability and erasability of the eraser.

The method for producing the eraser of the present invention will be described below.

First, the above-mentioned resin powder and polishing powder are mixed in a mixing and crushing machine such as an automatic mortar or ball mill to implant and fix the polishing powder on the surface of the resin powder as a core to obtain an abrasive. Next, a conventionally known eraser base material, particularly preferably a paste-like material obtained by adding a plasticizer, a stabilizer and the like to polyvinyl chloride or a copolymer of polyvinyl chloride and polyvinyl acetate, Add an abrasive and stir evenly
Then, if this is heat-molded, a desired eraser can be easily obtained.

In the present invention, it is needless to say that a filler, a fragrance, or the like can be further added if necessary.

(Example) Hereinafter, the present invention will be described in more detail based on examples.

Example <Production Method of Abrasive Material> 55 parts by weight of natural shirasu powder having an average particle size of about 10 μm (hereinafter simply referred to as “part”) and an average particle size of about 100 to 150 μm
55 parts of resin powder as a core consisting of polyvinyl chloride-vinyl acetate copolymer (Denka Vinyl SM-160, manufactured by Denki Kagaku Kogyo Co., Ltd.) was mixed in an automatic mortar for 90 minutes, and the surface of the resin powder was mixed with natural shirasu. Abrasive A110 in which powder is fixedly arranged
I got a part.

<Eraser manufacturing method> • Polyvinyl chloride 150 parts (Geon 121, manufactured by Nippon Zeon Co., Ltd.) • Dioctyl phthalate (plasticizer) 135 parts • Epoxidized soybean oil (stabilizer) 4 parts • Abrasive A 110 parts These components The mixture is uniformly stirred and mixed to form a paste-like product 399
A part was obtained and press molding was performed at 110 ° C. for 20 minutes to obtain an eraser.

Comparative Example An eraser was obtained in the same manner as in Example except that natural shirasu having an average particle size of 100 μm was used as an abrasive.

(Effects of the Invention) Using the eraser obtained in the above Examples and Comparative Examples, the image erased on the ordinary plain paper by the electrostatic copying method and the handwriting by a commercially available oil-based ballpoint pen were erased. Although the image and the handwriting were both erased, the paper surface was severely scratched and the appearance was remarkably deteriorated. On the other hand, the eraser of the embodiment could completely erase the image handwriting without damaging the paper surface. It was a thing. Thus, the eraser according to the present invention has an excellent effect.

Claims (1)

[Claims] 1. An eraser containing an abrasive comprising an eraser and an abrasive material in which abrasive powder having an average particle size smaller than that of the nucleus is fixedly arranged on the surface of the core made of resin powder.