JPH09175087A - Eraser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the resistance required for wearing off an eraser by containing spherical inorganic particles having the particle diameter within a given range. SOLUTION: Beads with filled inner sections and hollow balloons are used for spherical inorganic particles having the particle diameters of 5-200μm or less contained in an eraser. As an eraser components, platizol formed by mixing vinyl chloride resin of 100 pts.wt., a platicizer of 160 pts.wt., a stabilizer of 10 pts.wt., heavy calcium carbonate of 120 pts.wt. and glass beads GB731 are mixed and deformed to obtain a plastizol. The plastizol is filled in a container and thermoformed at 125 deg.C for 20 minutes by a hot press to manufacture the eraser. The resistance received at the time of erasing to the eraser containing spherical inorganic particles having the particle diameters of 5μm or more to 200μm or less is small, and hands are not tired at the time of erasing and paper surfaces are not damaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eraser for erasing handwriting such as pencils and mechanical pencils, and more specifically, it can be erased without applying force during erasing, so that the hand is not tired. Regarding eraser.

[0002]

2. Description of the Related Art Conventionally, an eraser is a vinyl chloride type using a vinyl chloride resin or a vinyl chloride copolymer as a base resin, a rubber type using a natural rubber or a synthetic rubber, and a vulcanization process. There is known one using a thermoplastic elastomer which is a rubber-like elastic body which is unnecessary. The eraser using vinyl chloride resin as the base resin is a mixture of vinyl chloride resin and a plasticizer, and if necessary, a filler and other additives, mixed paste-like plastisol is heated to add plasticizer to the vinyl chloride resin. Made by absorbing.
Eraser using natural rubber or synthetic rubber as base resin,
It is made by kneading natural rubber or synthetic rubber, sub and filler, and vulcanizing. An eraser using a thermoplastic elastomer as a base resin is produced by kneading a thermoplastic elastomer with a softening agent and a filler, and heat-molding the mixture in an unvulcanized state.

As the filler used for the eraser, inorganic powders such as heavy calcium carbonate, light calcium carbonate, silica, diatomaceous earth, magnesium oxide, talc, sericite and quartz powder are known. As the filler, those having a particle diameter of 5 μm or less are mainly used.

The above-mentioned eraser is used to erase the handwriting of a pencil or mechanical pencil. In order to erase the handwriting of a pencil or mechanical pencil with an eraser, the eraser needs to be worn due to scratching with paper. The reason is as follows. The handwriting with a pencil or mechanical pencil is the powder of the core of the pencil or mechanical pencil that has worn away due to scratching the paper and is attached to the paper surface. You can erase the handwriting by rubbing the handwriting of a pencil or mechanical pencil with an eraser because the wear powder of the core forming the handwriting is
This is because it is removed from the paper surface by reattaching to the eraser surface or the eraser scrap surface which is a worn eraser.

Unlike the above-mentioned eraser, the particle size is 10 μm
An eraser containing the above-mentioned inorganic powder having a large particle size is also known. It is a so-called abrasive eraser that erases the handwriting of an oil-based ballpoint pen and the image formed by the electrostatic copying method. The image formed by the handwriting of an oil-based ballpoint pen or the electrostatic copying method is different from the handwriting by the above-mentioned pencil or mechanical pencil, and has entered the concave and convex portions formed on the surface of the paper by the overlapping of the paper fibers. The coloring material is fixed to the paper fiber by a fixing agent such as resin. Therefore, the handwriting of the oil-based ballpoint pen and the image formed by the electrostatic copying method are not redeposited on the eraser surface. Therefore, in order to erase such handwriting, the eraser containing an abrasive is an inorganic powder having a large particle diameter of 10 μm or more, and is erased by cutting, peeling and removing the paper fiber to which the coloring material is fixed. . The large particle size inorganic particles having such an action are called an abrasive.

Various erasers containing an abrasive have been proposed. For example, an eraser (Japanese Patent Laid-Open No. 63-188099) containing an abrasive having an average particle size of 10 to 200 μm, the surface of which is subjected to a coupling treatment, or a particle size of 40
An eraser for erasing the handwriting of a ball-point pen containing an abrasive of ˜80 μm (JP-A-52-112429),
An eraser containing an abrasive having an average particle size of 30 to 170 μm (Japanese Patent Laid-Open No. 62-279997) is known.
Further, JP-A-3-53999 discloses that the particle diameter of the abrasive of the conventionally known eraser containing the abrasive is 30 to 200 μm.

An eraser containing a large type of inorganic particles other than the above-mentioned filler has also been proposed. It is a so-called solvent-containing eraser and is an eraser for erasing handwriting written in ink on a non-absorbing surface such as a film. In this solvent-containing eraser, a solvent that dissolves a dye that is a coloring material and a resin that is a fixing agent is present in the eraser, and the coloring material and the fixing agent are dissolved and erased by this solvent. Then, as one of the methods of incorporating a solvent into the eraser, there is a method of using inorganic particles having a large particle size. For example, inorganic hollow particles or inorganic hollow spherical particles are depressurized or pressurized in a solvent to impregnate the inorganic hollow particles with a solvent to form microcapsules, and an eraser containing the microcapsules (JP-A-54-54). No. 72121), and an eraser (Japanese Patent Laid-Open No. 3-108598) containing microcapsules obtained by destroying inorganic hollow particles and then dropping a solvent to impregnate the solvent to form microcapsules. ing.

[0008]

The problem is fatigue during use.
When erasing with an eraser, the force exerted on the hand holding the eraser is the sum of the force required for the eraser to wear and the frictional resistance between the eraser and the paper. Therefore, if the force required to wear the eraser is reduced, the force applied to the hand holding the eraser is reduced, and the eraser is less likely to be tired even when used. By the way, in the rubber industry,
The filler has different functions depending on its particle size,
It is known that it can be classified into the following four types. (1) Particle diameter 0.1 μm or less: Reinforcing agent that enhances physical strength. (2) Particle size 0.1 to 1 μm: Semi-reinforcing agent. (3) Particle size 1 to 5 μm: extender. (4) Particle diameter 5 μm or more: Deteriorating agent that weakens physical strength. From this fact, in order to make the eraser wear with a weak force when rubbing against the paper surface, the particle size of the filler is 5
It can be said that it is sufficient to use one having a size of μm or more.

However, the eraser containing the inorganic powder having a large particle diameter of 10 μm or more, like the eraser containing the abrasive, is erased by cutting and peeling the paper fiber on the paper surface to remove it. Even if there is a difference in degree, it will always damage the paper surface. For this reason, in an eraser for erasing the handwriting of a pencil or a mechanical pencil, when the inorganic particles having a particle diameter of 10 μm or more are contained, there is a problem that the paper surface is damaged.

Further, like the above-mentioned solvent-containing eraser,
Since the eraser containing the inorganic hollow particles containing the solvent needs to release the solvent at the time of erasing, the contained inorganic hollow particles are broken into small pieces during the erasing. For this reason,
The contained inorganic hollow particles do not act as a degrading agent. By the way, since these inorganic hollow particles are impregnated with a solvent by depressurization or pressurization, they have cracks or pores on the surface of the particles and are therefore considered to be easily broken.

That is, the problem to be solved by the present invention is:
It is an object of the present invention to provide an eraser that is easy to use and can be erased with a small force without damaging the paper surface at the time of erasing, and is easy to use.

[0012]

The present invention has a particle size of 5 to 20.
The gist is an eraser characterized by containing spherical inorganic particles of 0 μm.

The details will be described below. The eraser can be an eraser using a vinyl chloride resin, an eraser using a natural rubber or a synthetic rubber, and an eraser using a thermoplastic elastomer, but in particular, an eraser using a vinyl chloride resin, Great effect.

The base resin is a vinyl chloride resin using a vinyl chloride resin or a vinyl chloride copolymer, a rubber resin using a natural rubber or a synthetic rubber, and a rubber-like resin which does not require a vulcanization step. Examples thereof include thermoplastic elastomers that are elastic bodies. As a vinyl chloride resin, specifically, as a polyvinyl chloride, ZEON 121, 131 (above, manufactured by Nippon Zeon Co., Ltd.), VINICA P410, P44.
0, the same P510 (above, manufactured by Mitsubishi Kasei Vinyl Co., Ltd.), Luron TH-700, the same TH-1000, the same TH-1.
300 (above, manufactured by Tosoh Corporation) and the like, and as a vinyl chloride-vinyl acetate copolymer, Zeon 38J, 1
35J, 400X150 (above, ZEON Corporation)
Manufactured by Mitsubishi Kasei Vinyl Co., Ltd., Ryuron TC-806 (manufactured by Tosoh Corporation), and the like.

Specific examples of the thermoplastic elastomer include styrene-butadiene-styrene copolymers such as Tuffprene A, Tuffprene 125, 200 and 315.
Same 912, Sorprene T-406, same T-411, same T
-414, T-475, Asaprene T-420, T
-430, T-431, T-450 (all manufactured by Asahi Kasei Corporation), Califlex TR1101, and TR.
1102, TRKX138S, TR1118, T
R1116, same TR1184, same TR1186, same TR
1122, TR4113, TR4122, TR4
205, the same TR4260, the same TR4261, Kraton D1300 (above, Shell Chemical Co., Ltd. make) etc. are mentioned. As styrene-isoprene-styrene copolymer, Califlex TR1107, TR1111, TR
1112, TR1117 (above, Shell Chemical Co., Ltd.)
Manufactured). Styrene-ethylene butylene-
Tuftec H1052 and H1 as styrene copolymers
041, H1051 (all manufactured by Asahi Kasei Co., Ltd.),
Clayton G1650, G1652, G1657X
(Above, Shell Chemical Co., Ltd.), Lavalon SJ440
0, SJ5400, SJ6400, SJ740
0, SJ8400, SJ9400, SE540
0, SE6400, SS6400, SS740
0, SS9400, MJ4300, MJ630
No. 0, ME6301 (above, manufactured by Mitsubishi Petrochemical Co., Ltd.) and the like. Septone 2002, 2003 and 20 as styrene-ethylene propylene-styrene copolymers
23, 2043, 2063, 2005, 200
6, 2103, 2104, 2105, 4055
(Above, manufactured by Kuraray Co., Ltd.) and the like.

The vinyl chloride resin in the above base resin must be used in combination with a plasticizer. As the plasticizer, diethylhexyl phthalate, dinormaloctyl phthalate,
Polybasic acid ester plasticizers such as diisononyl phthalate, dibutyl phthalate, dioctyl adipate, dioctyl azelate, tricresyl phosphate, triethyl citrate, tributyl acetyl citrate, adipic acid, azelaic acid, sebacic acid, phthalic acid Polymers with dibasic acids and glycols such as, chlorinated paraffin, aliphatic hydrocarbons, polymers with epoxy fatty acid esters and glycerins and monobasic acids, acrylonitrile synthetic rubber, polymers such as polyethylene glycol esters Examples include plasticizers. The amount of plasticizer used depends on the type and combination with the base resin, but due to the hardness of the eraser,
It is desirable to use 80 to 200 parts by weight with respect to 100 parts by weight of the base resin.

The spherical inorganic particles used in the present invention are used as a deteriorating agent for reducing the abrasion strength of the eraser, and the particle size thereof needs to be 5 to 200 μm.
If the shape is not spherical, there is a problem that the paper surface is damaged when erased, and if the particle size is less than 5 μm, the action as a degrading agent is insufficient, and if the particle size exceeds 200 μm, the eraser There is a problem in that the physical strength becomes too weak, the amount of eraser waste increases, the eraser feels like it is collapsing, and the usability of the eraser deteriorates. Spherical inorganic particles are beads with the inside clogged,
There are hollow balloons. An example of a commercially available product will be given below. As the beads, Toshiba glass beads GB210 (average particle size: 17 μm) and GB7, which are made of glass, are used.
31M (average particle diameter 18 μm), GB731 (average particle diameter 30 μm), EGB731 (average particle diameter 18 μm)
m), the same GB301S (average particle size 45 μm) and Toshiba Blasting beads GB290 (particle size range 45-9).
0 μm), the same GB300 (particle size range 75 to 125 μm
m), the same GB320 (particle size range 106-180μ)
m), the same GB-J (particle size range 75 to 106 μm),
Medium and high refractive index glass beads used for retroreflective products HGB253 (particle size range 53 to 74 μm), H
GB275 (particle size range 74 to 105 μm), WGB2
20 (particle size range 5 to 44 μm), WGB243 (particle size range 53 to 63 μm), WGB276 (particle size range 8)
8 to 105 μm (above, manufactured by Toshiba Ballotini Co., Ltd.,
Examples include true specific gravity of 2.5 g / cc) and crystallized glass that is recrystallized by reheating glass beads. In addition, spherical copper powder, spherical bronze powder, and brass bronze powder can be used as metal products.

As the balloon, glass made of Scotchlite Glass Bubbles K1 (particles larger than 177 μm (residual ratio in a US 80 mesh sieve))
5 wt% or less, compressive strength 18 Kgf / cm2, specific gravity 0.125 g / cc, K25 (particles larger than 177 μm (residual rate in a US 80 mesh sieve) 5 wt% or less, compressive strength 53 Kgf / cm ² , Specific gravity 0.2
50 g / cc), K46 (particles larger than 149 μm (residual ratio in a US 100 mesh sieve)) 1% by weight
Below, pressure resistance 281 Kgf / cm ² , specific gravity 0.46
0 g / cc), the same S15 (particles larger than 105 μm (residual ratio in US 140 mesh sieve) 3% by weight)
Below, pressure resistance 21Kgf / cm2, specific gravity 0.150
g / cc), the same S60 (particles larger than 149 μm (residual ratio in a US 100 mesh sieve) 5% by weight
Below, pressure resistance 704Kgf / cm2, specific gravity 0.60
0 g / cc), the same B38 (particles larger than 177 μm (residual rate in a US 80 mesh sieve) 5 wt% or less, pressure resistance 282 Kgf / cm ² , specific gravity 0.380
g / cc) (above, manufactured by Sumitomo 3M Limited, average particle size is 70 μm), glass microballoon
IG101 (7% by weight of particles smaller than 44 μm, 175
Particles larger than μm 5% by weight, specific gravity 0.311 g / c
c), the same IG25 (21% by weight of particles smaller than 44 μm, 0% by weight of particles larger than 175 μm, specific gravity 0.23)
7 g / cc), same R (14% by weight of particles smaller than 44 μm, 8% by weight of particles larger than 175 μm, specific gravity 0.36)
1 g / cc), the same FT102 (5% by weight of particles smaller than 44 μm, 3% by weight of particles larger than 175 μm, specific gravity 0.250 g / cc), the same FTD202 (12% by weight of particles smaller than 44 μm, 0% by weight of particles larger than 175 μm) Specific gravity of 0.238 g / cc) (manufactured by Nippon Silica Industry Co., Ltd., all having an average particle diameter of 80 μm) and the like.

Microcells SL75 (particle size range 20-75 μm, average particle size 45)
μm), the same SL125 (particle size range 20 to 125 μm,
Average particle size 80 μm, SL150 (particle size range 20)
~ 150 μm, average particle size 100 μm), SL180
(Particle size range 20 to 180 μm, average particle size 115 μm
m) (above, manufactured by Onoda Cement Co., Ltd., all have a compressive strength of 700 Kgf / cm ² and a specific gravity of 0.68 to 0.70 g /
cc), glass microballoon FAA (particles smaller than 44 μm 2% by weight, particles larger than 175 μm 5% by weight, specific gravity 0.6 g / cc) (Nippon Silica Industry Co., Ltd.)
Manufactured, average particle size 80 μm) and the like.

Further, silica glass microballoon SI (9% by weight of particles smaller than 44 μm, 175 μm
Larger particles 0% by weight, specific gravity 0.254 g / cc)
(Manufactured by Nippon Silica Industry Co., Ltd., average particle size 80 μm),
Examples include aluminosilicate made of Philite 200/7 (particle size range of 5 to 150 μm, specific gravity of 0.7 g / cc) (manufactured by Nippon Philite Co., Ltd.).

Since the eraser is lighter in weight than the beaded one, the balloon-like one is more preferable because it feels lighter when the eraser is held and the resistance at the time of erasing is further emphasized. . However, since the hollow spherical inorganic particles have thin shell walls and are easily broken, the hollow inorganic particles must have strength so as not to be broken when the eraser is erased. The pressure resistance of the balloon is 13Kg so that it will not break when the eraser is erased.
f / cm ² or more, preferably 20 Kgf / cm ² or more. This was obtained from the results of a breaking test conducted on an eraser having the following composition. Eraser composition for destructive test Vinyl chloride resin (Zeon 121, manufactured by Nippon Zeon Co., Ltd.) 100 parts by weight Plasticizer (diisononyl phthalate) 160 parts by weight Stabilizer (epoxidized soybean oil) 1 part by weight Heavy calcium carbonate 35 parts by weight The above materials were mixed to form a paste, which was poured into a mold and subjected to hot press molding to obtain an eraser. A disk with a diameter of 3.0 mm is placed on this eraser surface at a constant speed (2 mm
The force at which the eraser is destroyed from the load applied to the disk when the surface of the eraser is destroyed when it is pushed in at a pressure of (/ min) was investigated. 1 if heating condition is 123 ℃, 20 minutes
Was 2.2 kgf / cm ^2, in the case of 130 ° C., 20 min was 19.1Kgf / cm ^2.

Since the true specific gravity of the spherical inorganic particles varies greatly depending on the material of the particles and whether they are beads or hollow, the amount of these spherical inorganic particles used is 5% by volume or more in the eraser. 50% by volume or less is desirable. If it is less than 5% by volume, the presence of spherical inorganic particles in the eraser is sparse and the number of particles that act during erasing may be small, so that the effect may not be obtained. If it is more than 50% by volume, the core of a pencil or mechanical pencil is worn out. The part of the eraser base material to which the powder is to be adhered becomes too small, and the erasability tends to decrease. The spherical inorganic particles may be used alone or in combination of two or more kinds,
You may use together with a conventionally well-known filler.

[0023]

The spherical inorganic particles having a particle size of 5 to 200 μm or less used in the present invention act as a deterioration agent that weakens the physical strength of the compounded product, so that the eraser wears with a smaller force. . Furthermore, since the spherical inorganic particles roll between the eraser and the paper and act as rollers, the frictional resistance between the paper and the eraser is also reduced. Therefore, the force required for the eraser to wear and the frictional resistance force are combined, and the resistance force that the hand holding the eraser receives at the time of erasing is also small. Therefore, the hand does not get tired when used. Further, since it has a spherical shape and has no projections for cutting or peeling the paper fiber, it does not damage the paper surface despite the large particle diameter.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to embodiments. Example 1 Vinyl chloride resin (Zeon 121, manufactured by Nippon Zeon Co., Ltd.) 100 parts by weight Plasticizer (diisononyl phthalate, hereinafter abbreviated as DINP) 160 parts by weight Stabilizer (epoxidized soybean oil) 10 parts by weight Heavy calcium carbonate (Filler: 55.5% or less of particles 5 μm or less 95.5% by weight, particles 5 μm or more 4.5% by weight, crushed shape) 120 parts by weight Toshiba Glass Beads GB731 316 parts by weight The above substances are mixed and defoamed to form plastisol. Then, this was filled in a container and heat-molded at 125 ° C. for 20 minutes with a heating press machine to obtain an eraser.

Example 2 Vinyl chloride resin (Zeon 121, described above) 100 parts by weight Plasticizer (DINP) 160 parts by weight Stabilizer (epoxidized soybean oil) 10 parts by weight Heavy calcium carbonate (described above) 120 parts by weight Glass Bubbles K25 10 parts by weight The above substance was treated in the same manner as in Example 1 to obtain an eraser.

Example 3 Vinyl chloride resin (Zeon 121, described above) 100 parts by weight Plasticizer (DINP) 160 parts by weight Stabilizer (epoxidized soybean oil) 10 parts by weight Heavy calcium carbonate (described above) 40 parts by weight High refractive index Glass beads WGB276 550 parts by weight The above substance was treated in the same manner as in Example 1 to obtain an eraser.

Example 4 Vinyl chloride resin (Zeon 121, described above) 100 parts by weight Plasticizer (DINP) 160 parts by weight Stabilizer (epoxidized soybean oil) 10 parts by weight Heavy calcium carbonate (described above) 120 parts by weight Glass Bubbles K25 5 parts by weight The above substance was treated in the same manner as in Example 1 to obtain an eraser.

Example 5 Vinyl chloride resin (Zeon 121, mentioned above) 100 parts by weight Plasticizer (DINP) 160 parts by weight Stabilizer (epoxidized soybean oil) 10 parts by weight Heavy calcium carbonate (described above) 40 parts by weight High refractive index Glass beads WGB276 700 parts by weight The above substances were treated in the same manner as in Example 1 to obtain an eraser.

Comparative Example 1 Vinyl chloride resin (Zeon 121, described above) 100 parts by weight Plasticizer (DINP) 160 parts by weight Stabilizer (epoxidized soybean oil) 10 parts by weight Heavy calcium carbonate (described above) 120 parts by weight An eraser was obtained in the same manner as in Example 1.

Comparative Example 2 Vinyl chloride resin (Zeon 121, described above) 100 parts by weight Plasticizer (DINP) 160 parts by weight Stabilizer (epoxidized soybean oil) 10 parts by weight Heavy calcium carbonate (described above) 120 parts by weight Advance-MSS P20N (spherical silica particles, beads, particle size 2.0 μm, specific gravity 2.0 g / cc, manufactured by Advance Co., Ltd.) 80 parts by weight The above substances were treated in the same manner as in Example 1 to obtain an eraser.

Comparative Example 3 Vinyl chloride resin (Zeon 121, mentioned above) 100 parts by weight Plasticizer (DINP) 160 parts by weight Stabilizer (epoxidized soybean oil) 10 parts by weight Heavy calcium carbonate (described above) 120 parts by weight Toshiba Blasting Beads GB-C (spherical glass particles, beads, particle size range 250 to 450 μm, specific gravity 2.5 g / cc, manufactured by Toshiba Ballotini Co., Ltd.) 100 parts by weight Obtained.

Various tests were conducted on the erasers obtained in Examples 1 to 5 and Comparative Examples 1 to 3. The results are shown in Table 1.

Measurement of resistance. The shape of the eraser is 5 mm, and the shape of the portion in contact with the paper is an arc with a radius of 6 mm. Apply this arc portion vertically to the paper surface and apply a vertical load of 100 g, 200 g, 3
00g and 400g were applied. Then, the paper was moved in the horizontal direction at a constant speed of 200 cm / min, and the horizontal force applied to the eraser at this time was measured. The value obtained by dividing this force (resistive force) by the vertical load was taken as the proportional coefficient.

Content of Spherical Inorganic Particles in Eraser The volume% of the spherical inorganic particles in the eraser was calculated from the specific gravity of the eraser containing no spherical inorganic particles and the specific gravity of the spherical inorganic particles. Since the specific gravity (ρ2) of the eraser containing no spherical inorganic particles depends on the compounding of the eraser, 1.32 g / cc was used in Examples 1, 2, 4 and Comparative Examples 2 and 3, and Examples 3, 5 Then, it was 1.19 g / cc. The calculation formula is as follows. V = Total volume of eraser V1 = Volume of spherical inorganic particles ρ1 = Specific gravity of spherical inorganic particles ρ2 = Specific gravity of eraser containing no spherical inorganic particles W1 = Part by weight of spherical inorganic particles W2 = Compound of other than spherical inorganic particles Weight part total Volume ratio of spherical inorganic particles (%) = V1 / V = (W1 / ρ
1) / (W1 / ρ1 + W2 / ρ2) × 100

Measurement of character erasure ratio It was measured by the method described in JIS S6050 "Plastic character eraser".

[0036]

[Table 1] In Comparative Example 3, the eraser collapsed and the measurement could not be performed in the resistance force measurement and the erasure rate measurement. Further, at the time of measuring the erasure rate, the paper surface after erasure was visually observed.
Also, in both Comparative Examples 1 and 2, the paper surface was not damaged.

[0037]

As described above in detail, the eraser containing spherical inorganic particles having a particle diameter of 5 μm or more and 200 μm or less has a small resistance to erasing and the hand is not tired during erasing.
Moreover, it does not damage the paper surface.

Claims (1)

[Claims] 1. An eraser containing spherical inorganic particles having a particle diameter of 5 to 200 μm.