JPH0353999A - Eraser composition - Google Patents

Abstract

PURPOSE:To obtain excellent erasing properties without damaging neither paper surface nor eraser shape by blending one kind of two kinds or more of ultrafine powder with a specific particle diameter or less as inorganic material powder with one kind or two kinds of silicon nitride whisker or/and silicon carbide whisker. CONSTITUTION:Inorganic powder material such as calcium carbonate and silicon dioxide being ultrafine powder with not more than 0.2mum particle diameter and silicon nitride whisker and silicon carbide whisker are blended with base material such as natural crude rubber, Factice and softening agent. The silicon nitride whisker is an aggregate of needle crystals forming fine particles of 0.1-1mum diameter and 10-200mum length and the silicon carbide whisker has a cubic crystal form of 0.05-1.50mum diameter and 20-200mum length causing silicon carbide to grow into a needle single crystal. When the silicon nitride whisker or silicon carbide whisker having needle crystal and cubic crystal forms and the ultrafine powder are blended into the eraser base material, an eraser eliminating fragility, reducing the damage of a paper surface at the time of erasure and having a soft feeling can be obtained in comparison with blending of carborundom, silica stone and glass powder having large particle diameters.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to writing lines with a yuzu ballpoint pen, printing with a typewriter, light printed materials, characters and figures of electronic copying machines such as PPC, word processors, and OA equipment such as personal computers. This invention relates to an eraser that can effectively erase printed characters and figures.

(Prior art) Ink typewriter erasers are used to erase writing lines with oil-based ballpoint pens, prints with typewriters, and characters and drawings with electronic copying machines. Carporundum, silica stone, A so-called "sand eraser" that is made by blending glass powder, natural shirasu, glass fiber, zirconia particles, etc., has been proposed. (Utility Model Publication No. 5182539), (Publication Special Publication No. 63-309500)
) In recent years, there has been a demand for higher grade and higher quality erasers due to the emergence of office automation equipment, etc., and erasers with various designs such as erasers that collect eraser scum and erasers for office automation have been provided.

(Problems to be Solved by the Invention) Conventional and commonly referred to as "sand letter erasers" are made by using one or more kinds of coarse particles with a particle diameter of usually 30 to 200 μm in the inorganic powdery substance contained in the abrasive. Since the particle size of zinc oxide, titanium oxide, and curk calcium carbonate used as fillers is 1 to 8 μm, it damages the paper surface when used, and in addition, the "sand eraser" itself is hard. Therefore, there were problems such as brittleness and a feeling of roughness during use.

(Means for Solving the Problems) The present invention solves the above-mentioned conventional problems, and enables writing lines and characters with an oil-based ballpoint pen, printing with a typewriter, and characters and drawings with an OA device with less damage to the paper surface and effectively. The object of the present invention is to provide an eraser that can be erased with a soft touch.

That is, the eraser of the present invention is made of natural raw rubber, Faticus (
It is made by blending a 4M-free powder material such as ultrafinely pulverized powder such as calcium carbonate or silicon dioxide with silicon nitride whiskers and silicon carbide whiskers into a base material such as white sub) or a softener.

As the ultrafinely ground rice powder in the present invention, calcium carbonate (for example, Homocal D; particle size 0.07 μm, manufactured by Hakuji Kogyo Co., Ltd.) is used.
Manufactured by MSK-C. particle size 0.03-0.04/tm manufactured by Ryumori Co., Ltd.), silicon dioxide (e.g. Aeji 1 Zil P)
25; particle size 0.03 μm (manufactured by Nippon Aerosil Co., Ltd.), etc. can be preferably used.

In addition, silicon nitride whiskers are aggregates of needle-like crystals with a diameter of 0.
．． 1~1μm length 10~. 200/tm powder, silicon carbide whiskers are made by elongating silicon carbide into needle-like single crystals, and have a cubic crystal shape with a diameter of 0.05 to 1,50 μm and a length of 20 to 200 μm. It is something. The silicon nitride whiskers or silicon carbide whiskers having such acicular crystal/cubic crystal shapes and the ultrafinely pulverized powder are erased. By blending it into the base material, compared to the case where carborundum, silica, or glass powder with coarse particle size is blended, it eliminates brittleness, reduces damage to the paper surface during erasing, and makes it soft to use. You can get a nice eraser. Furthermore, when manufactured by extrusion, the acicular crystals and cubic crystals become intertwined, providing a reinforcing effect to the eraser and increasing its shape stability.

Eraser base material, ultra-finely ground powder, gay nitride whiskers,
The blending ratio of silicon carbide whiskers is preferably 40 to 50% by weight, and the blending ratio of ultrafine powder to silicon nitride whiskers and silicon carbide whiskers is in the range of about 1:1 to 1:4, preferably 1:2 to 1:2. Can be used in a 1 to 3 range. If the ratio is less than 1:1, the erasing effect will be small. If the ratio exceeds 1 to 4, the erasing effect will be greater, but the soft feel during erasing will be lost and brittleness will appear.

The eraser of the present invention is manufactured by adding a predetermined proportion of the above-mentioned ultrafinely pulverized powder and additives such as silicon nitride whiskers, silicon carbide whiskers, other ingredients, and a vulcanization accelerator to raw rubber, fatics, and a softener. It can be easily produced by sufficiently kneading and then shaping it according to a conventional method.

(Function) Writing lines and letters with a ballpoint pen, printing with a typewriter, erasing of letters and figures with ○A ja HH are the same as those contained in liquid or solid ink or ribbon containing resin. The process involves removing dyes or pigments from between the fibers of paper. Deletion from between the fibers depends on the abrasive material, but if the abrasive force is excessive, the damage to the paper surface will be significant, and if the abrasive force is weak, the erasing power will be poor. In addition, the finer the particle size of the powder used as a filler, the softer it feels when used due to the reinforcing properties of the network chains spatially distributed within the rubber base material and the adhesive network chains distributed on the surface of the particle interface. From this point of view, if the size of the abrasive is in the form of needle-like crystals or cubic crystals with a diameter of 0.05 to 1.50 μm and a length of 200 μm, damage to the paper surface can be reduced. It is thought that the ultrafinely pulverized powder is densely packed between the acicular and cubic crystals, thereby interfering with the abrasive action, and further providing a soft feel due to the reinforcing properties of the network chains.

(Example) The present invention will be specifically explained with reference to the following Examples and Comparative Examples.

Example-1 RSS I'hl raw gold, 15 parts by weight Golden Factis [manufactured by Tenma Sub Kako ■] 30 parts by weight Machine oil (softening agent) 5 parts by weight Calcium carbonate Pomocal D [manufactured by Shiraishi Kogyo ■] 10 parts by weight Sulfur (vulcanizing agent) 1.3 parts by weight Di-0-1 lyl guanidine (vulcanization accelerator) 0.2 parts by weight Magnesium oxide (vulcanization accelerator) 5 parts by weight Ganitride whiskers [manufactured by Tateho Chemical Industry Co., Ltd.] ) 3 3. 5 parts by weight Of the above blend, first 1 part raw rubber was added using an open mill.
After masticating at 30° C. or higher, the mixture is sufficiently kneaded with other ingredients using a Hanhari mixer. Next, after dispensing, press vulcanization was carried out, and the eraser was then cut to obtain an eraser.

Example-2 RSS llhl raw rubber golden factis [Made by Tenma Sub Kako] Machine oil (softener) Calcium carbonate Homocal D [Made by Shiraishi Kogyo ■] Silicon dioxide Aerosil P25 [Made by Nippon Aerosil ■] Sulfur (vulcanizing agent) Di-0-tolylguanidine (vulcanization accelerator) Magnesium oxide (vulcanization accelerator) silicon nitride whiskers [Made by Tateho Chemical Industry ■] 5 parts by weight 30 parts by weight 5 parts by weight 7 parts by weight 3 parts by weight 1.3 parts by weight 0.2 parts by weight 5 parts by weight 33.5 parts by weight Treated in the same manner as in Example 1, I got it.

Eraser of the same shape Comparative example-1 RSS Aim 1 raw rubber golden factis [Made by Tenma Sub Kako] Machine oil (softener) Calcium carbonate Hoshical D [Made by Shiraishi Kogyo ■] Sulfur (vulcanizing agent) Di-1tolylguanidine (vulcanization accelerator) Magnesium oxide (vulcanization accelerator) Silica sand (particle size 40-160μm) 15 parts by weight 30 parts by weight 5 parts by weight 10 parts by weight 1.3 parts by weight 0.2 parts by weight 5 parts by weight 33.5 parts by weight Treated in the same manner as in Example 1, I got it.

Eraser of the same shape, Comparative Example-2 RSS 1 Raw Rubber Golden Factis [manufactured by Tenma Zubu Kako 01] ■ 5 parts by weight 30 parts by weight 9 Machine oil (softening agent) 5 parts by weight Calcium carbonate Homocal D [Shiraishi Kogyo ■ ] 10 parts by weight sulfur (
Vulcanizing agent) 1.3 parts by weight Di-1-tolylguanidine (vulcanization accelerator) 0.2 parts by weight heavy calcium carbonate (particle size 1-8 μm) 5 parts by weight gay sand (particle size 40-160 μm) 33 0.5 parts by weight The same procedure as in Example 1 was carried out to obtain erasers and rubbers of the same shape.

Table 1 shows the physical properties, erasing performance, etc. of the erasers obtained in Examples and Comparative Examples.

1 0 Judgment Criteria ◎ Good ○ Good △ Poor (Effects of the present invention) As detailed above, the eraser of the present invention can erase writing lines written with an oil-based ballpoint pen, typewriter prints, letters, drawings, etc. made with OA equipment in a soft manner. When used, it does not damage the paper surface, and even if strong force is applied during use to erase, the shape of the eraser is not damaged, and it has excellent erasing performance, making it suitable as an eraser for oil-based ballpoint pens and typewriters. It can be used for.

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Claims (1)

[Claims] One or more types of ultrafinely pulverized powder with a particle size of 0.2 μm or less and one or two types of silicon nitride whiskers and/or silicon carbide whiskers are blended into an eraser base material using natural raw rubber fatix as an inorganic powder. An eraser composition characterized by: