JPH0825888A - Erazer rubber composition - Google Patents

Abstract

PURPOSE:To make it possible to fully erase mark written with a ballpoint pen and only ink or the like through a small number of rubbing times by a method wherein deliquescent substance is added to erazer rubber composition. CONSTITUTION:Deliquescent substance, which is present on the surface of erazer rubber and contacts with the air, among the deliquescent substances such as calcium chloride anhydride, calcium chloride dihydrate or the like added to erazer rubber composition, deliquesces so as to moisten the surface of the erazer rubber with a certain amount of water. As a result, only by rubbing the surface of paper with the erazer rubber composition, the fibers in paper are swollen by the water and readily peeled off the surface of paper. In addition, no water runs out or is dried up. Since the deliquescent substance is mixed with the erazer rubber under dry state, no molding trouble due to the generation of steam at the molding of erazer rubber also develops.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an eraser composition capable of erasing not only handwriting with a pencil or a mechanical pencil but also handwriting with an oil-based ballpoint pen or handwriting fixed on the surface layer of paper such as an image by printing. Regarding

[0002]

2. Description of the Related Art A handwritten or printed image of an oil-based ballpoint pen written on paper cannot be erased with an ordinary pencil eraser. This is because even though the oil-based ballpoint pen ink and printing ink do not penetrate into the paper by capillarity due to their high viscosity, they are achieved even in the concave and convex parts of the surface layer of the paper formed by the overlapping of paper fibers. Furthermore, the coloring material is fixed to the paper fibers by the binder due to the evaporation of the solvent in the ink. Therefore, in order to erase the handwriting of the oil-based ballpoint pen and the image formed by printing (hereinafter referred to as handwriting), an eraser is mixed with an abrasive such as inorganic particles. That is, the erasing is performed by peeling the paper fibers on which the coloring material is fixed with an abrasive from the paper surface.

[0003]

In paper, paper fibers are intertwined with each other firmly. For this reason, even if you use an eraser containing an abrasive, it is necessary to rub the paper surface many times in order to remove the paper fibers and erase it. Compared to the number of rubbing required to do, it is high. That is, erasing the handwriting with an eraser containing an abrasive material takes longer than erasing the handwriting with a pencil or a mechanical pencil.

It is conceivable to use water to shorten the time for erasing the handwriting. This is a method that utilizes the property that paper fibers swell when they get wet with water, and the paper fibers are easily peeled off, and the paper fibers are peeled off even with a slight rubbing. However, if the method of wetting the paper with water and then rubbing it with an eraser is adopted, two steps, that is, a step of wetting with water and a step of rubbing with an eraser are required, and if too much water is added, the paper will be There is also the problem of easy tearing and wrinkling. Moreover, in order to always apply a certain amount of water, it is necessary to use an erasing aid, which is a brush or pen-shaped object other than the eraser and which is moistened with water.

In order to solve the above problem, a method of using an eraser whose surface is always wet can be used instead of the method of once wetting the paper surface with water and then rubbing it with an eraser. When such an eraser is used, the paper is wet by simply rubbing the surface of the paper with the eraser, the paper fibers are easily peeled off, and the erasing can be performed with a small number of rubbing. By the way, in order to make the surface of the eraser always wet, it is possible to adopt a method in which the eraser contains water. However, when the eraser is made to contain water, if the raw material before molding is made to contain water and then the eraser is molded, the molding temperature of the eraser is generally higher than 100 ° C, which is the boiling point of water, so a large amount of water vapor is generated during molding. As a result, molding becomes difficult, and water evaporates and disappears. Therefore, it is necessary to make the eraser after molding contain water. However, when water is contained in the eraser after molding, it must be permeated from the surface of the eraser into the eraser, and it is necessary to soak it in water for a long time or soak it in water to apply pressure, which is troublesome. It also causes deterioration of the eraser. Furthermore, since the volume inside the eraser is increased by the volume of the contained water, the eraser is deformed or cracked. Even when the eraser contains water in the form of gel, the water evaporates during long-term storage,
It will dry out and lose its effect.

[0006]

DISCLOSURE OF THE INVENTION The gist of the present invention is an eraser composition containing a deliquescent substance. The details will be described below. The deliquescent substance is used for keeping the surface of the eraser composition always wet with water, and refers to a substance in which the saturated aqueous solution has a vapor pressure lower than the vapor partial pressure in the atmosphere. In other words, it is a substance that has the property of capturing water vapor in the atmosphere and dissolving it in the water. Many deliquescent substances are known, both inorganic substances and organic substances, but considering that they are used in combination with an eraser composition, they have low toxicity and evaporate at the molding temperature of the eraser.
It must be one that does not sublime, decompose, or transform into a non-deliquescent substance.

Specific examples of these substances include potassium nitrite, calcium chloride anhydrous salt, calcium chloride monohydrate, calcium chloride dihydrate, calcium chloride hexahydrate, zinc bromide trihydrate, copper bromide ( II) Anhydrous salt, copper (II) bromide
Tetrahydrate, nickel (II) bromide trihydrate, magnesium bromide hexahydrate, potassium metasilicate, potassium metaborate,
Sodium iodide anhydrous salt, sodium iodide dihydrate, nickel (II) iodide anhydrous salt, nickel (II) iodide
Hexahydrate, sodium hydrogensulfate monohydrate, sodium sulfate anhydrous, ammonium citrate, potassium acetate, choline,
Betaine etc.

Among the above-mentioned deliquescent substances, calcium chloride anhydrous salt and calcium chloride dihydrate are preferable because they have low toxicity, are often used as a desiccant, and have strong deliquescent property. The above deliquescent substances may be used either individually or in combination of two or more. The amount of the deliquescent substance added was 0.
It is preferably 1% by weight or more and 20% by weight or less, and more preferably 0.5% by weight or more and 10% by weight or less. If the amount is less than 0.1% by weight, the amount of water when deliquescent is small and the effect of swelling the paper fibers may be small. If the amount is 20% by weight or more, the deliquescent substance on the surface of the eraser occupies the deliquescent substance after deliquescent. Since the space occupied by the liquid is occupied by the liquid, the eraser becomes too brittle and the force of rubbing the paper surface becomes weak, and the number of times of erasing may increase.

As the material of the eraser composition other than the deliquescent substance, those used in the rubber-based, polyvinyl chloride-based and thermoplastic elastomer-based erasers which have been conventionally used can be used. As the base material, natural rubber, synthetic rubber, and substituate are used in the rubber system, polyvinyl chloride and vinyl chloride-vinyl acetate copolymer are used in the polyvinyl chloride system, and styrene-based thermoplastic elastomer is used in the thermoplastic elastomer system. Olefin-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer and the like can be used. In addition to these, polyethylene, polypropylene, polyethylene vinyl acetate, polyethylene ethyl acrylate, chlorinated polyethylene, polyacrylate, polymethacrylate, etc. can be added as a resin for modifying physical properties. In addition, plasticizers, softeners, fillers, antioxidants, light resistance stabilizers, lubricants, colorants and the like can be used as common materials, which is the same as conventional erasers.

The abrasive may not be used in particular, but if used in combination, the number of times of rubbing with an eraser until erasing can be reduced. Abrasives that can be used can be the abrasives that have been conventionally compounded in the eraser, specifically, carborundum,
Examples include fused alumina, glass powder, silica sand, quartz powder, and shirasu. When using abrasives, the base material of the eraser is
A rubber-based or thermoplastic elastomer-based eraser is preferable because it has a strong holding force for the abrasive.
In particular, a thermoplastic elastomer type that is stable over time is desirable. When the thermoplastic elastomer contains an abrasive, in order to prevent the abrasive from being detached from the base material,
It is particularly useful to treat the surface of the abrasive with a coupling agent as disclosed in JP-A-3-1997.

[0011]

[Function] Among the deliquescent substances contained in the eraser composition, the deliquescent substance which is on the surface of the eraser and is in contact with the atmosphere is deliquescent and the surface of the eraser is always wet with constant water. Therefore, in the present eraser composition, the paper fibers are swollen with water only by rubbing the surface of the paper, and immediately peeled off from the surface of the paper. Moreover, it does not dry out of water. Since the deliquescent substance is blended in the eraser in a dry state, there is no possibility that water vapor is generated during the molding of the eraser and molding becomes difficult. Furthermore, by covering the eraser itself with a substance that does not allow water vapor to pass easily, the eraser will not get wet with water during storage and stain the surrounding objects. For example, wrap the eraser with a polyethylene film and heat weld it,
There is a method of covering the eraser by blending the wax-like substance in the eraser and forming a wax film by blooming of the wax-like substance on the surface of the eraser after molding. In this way, the part covered with a substance that is hard to pass water vapor will not get wet with water, and the film covering the eraser will not be rubbed by rubbing the paper surface, so the part that rubs the paper surface will always be wet. It becomes a state.

[0012]

EXAMPLES The present invention will be described below. Example 1 Sorprene T-475 25 parts by weight (styrene-based thermoplastic elastomer, manufactured by Asahi Chemical Industry Co., Ltd.) Mirastomer 6030N 25 parts by weight (olefin-based thermoplastic elastomer, manufactured by Mitsui Petrochemical Co., Ltd.) IRGANOX1010 0.2 parts by weight Parts (stabilizer, Germany, manufactured by CIBA-GEIGY) Chronos KA-10 6 parts by weight (titanium oxide, manufactured by Titanium Industry Co., Ltd.) KP Parmis KP-60F 84.3 parts by weight (shirasu, abrasives, Kyoritsu kiln) Raw material Co., Ltd.) Calcium chloride dihydrate (deliquescent substance) 7 parts by weight Sorprene T-47 with two rolls heated to 120 ° C.
5. Knead the Mirastomer 6030N well and add the rest of the mixture to this and knead. The kneaded product was placed in a mold and press-molded at 120 ° C. for 10 minutes to obtain a block-shaped eraser composition.

Example 2 Sorprene T-414 25 parts by weight (styrene-based thermoplastic elastomer, manufactured by Asahi Chemical Industry Co., Ltd.) Evaflex 210 25 parts by weight (ethylene vinyl acetate copolymer resin, manufactured by Mitsui DuPont Polychemical Co., Ltd.) ) IRGANOX 1010 (previously described) 0.2 parts by weight Crystallite granules 80-150 Mesh 50.2 parts by weight (quartz powder, abrasive, manufactured by Tatsumori Co., Ltd.) Potassium acetate (deliquescent substance) 10 parts by weight The above components were carried out. An eraser composition was obtained in the same manner as in Example 1.

Example 3 20 parts by weight of Kraton G1650 (styrene elastomer, manufactured by Shell Chemical Co., Ltd.) 20 parts by weight of UBE L519 (polyethylene, manufactured by Ube Industries, Ltd.) 10 parts by weight of Alcon P-125 (saturated alicyclic group) Hydrocarbon resin, manufactured by Arakawa Hayashi Chemical Co., Ltd.) IRGANOX1010 (previously described) 0.2 parts by weight WA # 320 61.2 parts by weight (fused alumina, abrasive, Fujimi Abrasives Co., Ltd.) Heavy carbonic acid Calcium 25 parts by weight Calcium chloride anhydrous salt (deliquescent substance) 25 parts by weight The above components were treated in the same manner as in Example 1 to obtain an eraser composition.

[0015]Example 4  In Example 1, KP Permis KP-6, which is an abrasive
Silane coupling as follows instead of 0F
Example 1 except that an abrasive whose surface was treated with an agent was used.
An eraser composition was obtained in the same manner as in. <Surface treatment of abrasives> KP Permis KP-60F 100 parts by weight Toray Silicone SH6026 0.5 parts by weight (silane coupling agent, Toray Silicone Co., Ltd., 40% methanol solution of active ingredient) Water 6 parts by weight Part After dissolving the silane coupling agent in water and hydrolysis,
Spray this on the stirring KP Permis KP-60F
And then dried.

Example 5 In Example 2, crystallite granules as an abrasive
An eraser composition was obtained in the same manner as in Example 2 except that an abrasive whose surface was treated with a silane coupling agent as described below was used instead of 80 to 150 Mesh. <Surface treatment of abrasives> Crystallite granules 80 to 150 Mesh 50 parts by weight Toray Silicone SH6075 0.2 parts by weight (silane coupling agent, manufactured by Toray Silicone Co., Ltd.) Water 200 parts by weight Silane coupling agent in water After dissolving and hydrolyzing,
Put crystallite granules in this and stir, then,
The abrasive was separated by suction filtration and dried.

Example 6 Example 3 was the same as Example 3 except that, instead of WA # 320 as the abrasive, an abrasive surface-treated with a titanate coupling agent was used as follows. An eraser composition was obtained in the same manner. <Surface treatment of abrasives> WA # 320 60 parts by weight Titacoat S231 1.5 parts by weight (titanate coupling agent, 80% IPA solution of active ingredient, manufactured by Nippon Soda Co., Ltd.) Isopropyl alcohol 5 parts by weight Titanate in isopropyl alcohol After the system coupling agent was dissolved, it was sprayed onto the stirring WA # 320 and then dried.

Comparative Example 1 An eraser composition was obtained in the same manner as in Example 1 except that the deliquescent substance calcium chloride dihydrate was removed.

Comparative Example 2 An eraser composition was obtained in the same manner as in Example 2, except that the deliquescent substance potassium acetate was removed.

Comparative Example 3 An eraser composition was obtained in the same manner as in Example 3 except that calcium chloride anhydrous salt which was a deliquescent substance was removed.

An erasability test was conducted using the eraser compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 3 above. The results are shown in Table 1.

Erasability test On black paper (JIS P3201), write letters with a black oil-based ballpoint pen (BK-70, manufactured by Pentel Co., Ltd.),
The handwriting was rubbed with an eraser composition, and the number of rubs before erasing was measured. The completion of erasing was visually determined.

[0023]

[Table 1]

[0024]

[Effect] The eraser composition according to the present invention can completely erase the handwriting of an oil-based ballpoint pen or the like with a small number of times of rubbing. Of course, erasing the handwriting of a pencil is also good. When the eraser obtained in the example was wrapped with low density polyethylene, the eraser surface did not get wet.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 31, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

In order to solve the above problem, a method of using an eraser whose surface is always wet can be used instead of the method of once wetting the paper surface with water and then rubbing it with an eraser. When such an eraser is used, the paper is wet by simply rubbing the surface of the paper with the eraser, the paper fibers are easily peeled off, and the erasing can be performed with a small number of rubbing. By the way, in order to make the surface of the eraser always wet, it is possible to adopt a method in which the eraser contains water. However, when the eraser is made to contain water, if the raw material before molding is made to contain water and then the eraser is molded, the molding temperature of the eraser is generally higher than 100 ° C, which is the boiling point of water, so a large amount of water vapor is generated during molding. As a result, molding becomes difficult, and water evaporates and disappears. Therefore, it is necessary to make the eraser after molding contain water. However, when water is included in the eraser after molding, it must be permeated from the surface of the eraser into the eraser, and it is necessary to soak it in water for a long time or soak it in water to apply pressure, which is troublesome. It also causes deterioration of the eraser. Furthermore, since the volume of the eraser increases by the volume of the contained water, the eraser is deformed or cracked. Even when the eraser contains water in the form of gel, the water evaporates during long-term storage,
It will dry out and lose its effect.

Claims (1)

[Claims] 1. An eraser composition containing a deliquescent substance.