JP2000043492A - Rubber based eraser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber based eraser at a low cost, which can surely erase the writing traces of a pencil or a mechanical pencil or the like without fouling a paper face at the time of erasing, and in addition, is excellent in heat-resistance, and is effective in the environmental preservation by being formed using used rubber products (waste rubber) which have been discarded. SOLUTION: This rubber based eraser is formed by containing natural rubber, synthetic rubber emulsion based rubbers or polypropylene, a simple substance of polyethylene based plastics, or a composite raw material of them, a filler, an erasure improving agent, and also, a softener, a coloring agent, a vulcanization accelerating assistant, a vulcanization accelerator, a vulcanizing agent and material components of them by required compounding amounts (wt.%) in a reclaimed rubber which does not contain carbon black, or used rubber powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber-based eraser (generally referred to as an eraser) mainly composed of rubber for erasing handwriting of a pencil, a mechanical pencil or the like, and particularly to an environmental treatment problem. Used rubber products (waste rubber) that are disposed of as waste at the time of use
And a rubber-based eraser using

[0002]

2. Description of the Related Art Polyvinyl chloride (PVC) is blended with a plasticizer and an inorganic filler and the like is gelled by heating.
A system eraser is already known (Japanese Patent Publication No. 49-2924).
No. 9). As an eraser using a used rubber product, for example, a thermoplastic elastomer (TP
E), there is known a TPE-based eraser obtained by mixing used tire powder (waste tire powder) as a filler and eraser improving agent (refer to JP-A-5-345499).

[0003]

However, since the above-mentioned conventional TPE-based eraser uses tire powder of used tires of automobiles and the like, it is necessary to erase the handwriting of a pencil or a mechanical pencil from the paper. Sometimes, when the eraser is rubbed against the paper surface, carbon black contained in a large amount in the tire powder is transferred to the paper surface, and the paper surface may be stained black. In other words, the cause of soiling the paper surface is the presence of carbon black contained in the TPE-based eraser, and when the eraser is rubbed against the paper surface, the carbon black may remain as black streaks on the paper surface. Was desired.

[0004] Further, the conventional TPE-based eraser uses a thermoplastic elastomer which is inferior in heat property, and thus has a problem in maintaining performance at high temperatures. Specifically, the thermoplastic elastomer is softened by the softening of the polymer in a high-temperature atmosphere of, for example, 60 ° C. to 80 ° C., and the amount of erased dust generated when handwriting is erased increases. In other words, the conventional eraser using a thermoplastic elastomer has an abnormally large amount of eraser dust generated at the time of erasing and is intensely consumed, so that its life is short and uneconomical.

The present invention has been made in view of such circumstances as described above, and an object of the present invention is to provide a method for erasing handwriting such as a pencil or a mechanical pencil without soiling the paper surface. An object of the present invention is to provide a low-cost rubber-based eraser which is made of waste rubber products (waste rubber) which is excellent in heat resistance and is excellent in environmental protection.

[0006]

SUMMARY OF THE INVENTION In order to achieve the object, the present invention is directed to a recycled rubber, a natural rubber, a synthetic rubber emulsion rubber or a polypropylene or a polyethylene plastic which does not contain carbon black. A major feature is that it contains at least a composite material, a filler, and a eraser. Specifically, used rubber products that do not contain carbon black are processed and regenerated by a well-known method for producing regenerated rubber. Natural rubber, synthetic rubber emulsion rubber or polypropylene, polyethylene plastics alone or These composite materials, fillers, erasers, softeners, coloring agents, vulcanization accelerators, vulcanization accelerators, vulcanizing agents These raw materials are contained in the required amounts (% by weight). That is what you do.

Further, the present invention is directed to a used rubber powder containing no carbon black, a natural rubber, a synthetic rubber emulsion rubber or a polypropylene or polyethylene plastic alone or a composite material thereof, a filler, and an improved eraser. There is a great feature in that the composition contains at least an agent.
Specifically, used rubber products that do not contain carbon black are processed and pulverized to a predetermined particle size by a well-known rubber powder manufacturing method, into natural rubber, synthetic rubber emulsion rubbers or polypropylene, polyethylene. -Based plastics or their composite materials, fillers, erasers, softeners, coloring agents, vulcanization accelerators, vulcanization accelerators, vulcanizing agents. (% By weight).

In the present invention, examples of used rubber products which do not contain a carbon rack used as recycled rubber and used rubber powder include white rubber such as rubber bands and rubber gloves. The particle diameter of the used rubber powder is 1 mm. Or less, preferably 0.5 mm or less, particularly preferably 0.3 mm or less. Examples of the synthetic rubber emulsion rubbers include styrene-butadiene rubber. Further, as a simple substance of polypropylene plastics, atactic polypropylene and the like can be mentioned, and as a simple substance of polyethylene plastics, low molecular polyethylene and the like can be mentioned. Also, as the filler, heavy calcium carbonate,
Inorganic powders such as recycled glass powders are mentioned. The average particle diameter of the inorganic powders is in the range of 1 to 120 μm. As the eraser, white compounds such as compounds obtained by adding sulfur chloride to used vegetable oil are used. Sub is mentioned. In particular, a white sub using a compound obtained by adding sulfur chloride to regenerated rapeseed oil (hereinafter simply referred to as white sub) is desirable. Examples of the softener include process oil. Examples of the coloring agent include titanium oxide. In addition, examples of the vulcanization accelerator include magnesium oxide. Also, as a vulcanization accelerator,
Tetramethylthiuram disulfide (hereinafter abbreviated as TMTD) and the like. The vulcanizing agent includes precipitated sulfur and the like.

According to the rubber-based eraser according to the above-described technical means of the present invention, when erasing a handwriting such as a pencil or a mechanical pencil from the paper surface, the paper surface becomes dirty even if the eraser is rubbed against the paper surface. There is no. That is, since carbon black, which causes soiling of the paper surface, is not included in the eraser, there is no possibility that the paper surface will be soiled. In addition, since it is excellent in heat resistance, there is no possibility that a problem occurs in maintaining performance at high temperatures. That is, the amount of erase dust generated at the time of erasing can be suppressed to the same state as at normal temperature.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to specific examples. The rubber-based eraser of the present invention according to claims 1 and 3 is a simple substance of a recycled rubber, a natural rubber, a synthetic rubber emulsion-based rubber or a polypropylene, a polyethylene-based plastic, or a composite thereof, which does not contain carbon black as an essential component. At least a material, filler, and eraser are included. Specifically, used rubber products that do not contain carbon black, such as rubber bands and rubber gloves, are processed and reclaimed by a well-known method for producing reclaimed rubber. Natural rubber, styrene-butadiene rubber, heavy calcium carbonate, Glass powder, white sub,
Process oil, titanium oxide, magnesium oxide, TM
TD and settled sulfur are required to be contained in a required amount (% by weight). In addition, heavy calcium carbonate and recycled glass powder used as a filler have an average particle diameter of 1 to 120.
A range of μm is desirable.

Example 1 Recycled rubber 11% by weight Natural rubber 3% by weight Styrene-butadiene rubber 3% by weight Heavy calcium carbonate, recycled glass powder 22% by weight White sub 52% by weight Process oil 0.5% by weight Titanium oxide 0.5% by weight Oxidation Magnesium 7% by weight TMTD 0.5% by weight Precipitated sulfur 0.5% by weight Well-stirred and kneaded each of the above ingredients using a well-known method for producing an eraser, for example, a Banbury mixer or the like. To obtain an appropriately shaped rubber eraser.

The rubber-based eraser of the present invention according to claims 2 and 3 is a rubber-based eraser which does not contain carbon black as an essential component, a natural rubber, a rubber-based synthetic rubber emulsion, or a polypropylene-based or polyethylene-based plastic. Or at least a composite material, a filler, and a character eraser. Specifically, used rubber products that do not contain carbon black are processed and pulverized to a predetermined particle size by a known rubber powder manufacturing method into used rubber powder, natural rubber, styrene-butadiene rubber,
Heavy calcium carbonate, recycled glass powder, white sub, process oil, titanium oxide, magnesium oxide, TMTD,
Precipitated sulfur is to contain these in a required blending amount (% by weight). Further, the particle diameter of the used rubber powder not containing carbon black used in the present invention is 1 mm or less, preferably 0.5 mm or less, particularly preferably 0.3 mm or less.
It is as follows.

Example 2 Used rubber powder 6% by weight Natural rubber 11% by weight Styrene / butadiene rubber 3% by weight Heavy calcium carbonate, recycled glass powder 19% by weight White sub 52% by weight Process oil 0.5% by weight Titanium oxide 0.5% by weight % Magnesium oxide 7% by weight TMTD 0.5% by weight Precipitated sulfur 0.5% by weight

Next, a function retention test for the rubber-based eraser of the present invention and the conventional TPE-based eraser obtained in each of the above-described Examples 1 and 2 was performed under the following test conditions. Table 1 shows the results. Here, ○ shown in the table indicates that the amount of erased dust is not different from that at normal temperature, Δ indicates that the amount of erased dust is about twice that at normal temperature, and × indicates the amount of erased dust. It shows that the generation amount is about three times that at normal temperature. Test conditions Pencil used: HB of pencil specified in JIS S 6006 Test paper: Paper A specified in JIS P 3201 Room temperature: 23 ° C Heater: Key-type heat aging tester

[0015]

[Table 1]

As is clear from Table 1, the rubber-based eraser of the present invention shows that the amount of erased scrap at 60.degree. C. and 80.degree. It turns out that it does not change. On the other hand, in the case of the conventional TPE-based eraser, the amount of erased dust at 60 ° C. is about twice that at normal temperature, and at 80 ° C., the amount of erased dust is about three times that at normal temperature. Accordingly, it can be seen that the rubber-based eraser of the present invention is superior in maintaining performance at high temperatures as compared with the conventional TPE-based eraser.

[0017]

Since the rubber-based eraser of the present invention is constituted as described above, the following effects are obtained. . When erasing handwriting such as a pencil or a mechanical pencil from the paper surface, the paper surface is not stained even if an eraser is rubbed against the paper surface. That is, since carbon black, which is a factor that stains the paper surface, is not included in the eraser, there is no risk of soiling the paper surface. In addition, there is no fear that a problem occurs in maintaining the performance at a high temperature. That is, the amount of erase dust generated at the time of erasing can be suppressed to the same state as at normal temperature.

[0018] As a used filler, the used recycled glass powder that serves as an abrasive when rubbed against the paper surface is used, so it is possible to reduce costs, as well as handwriting such as pencils and mechanical pencils from the paper surface. When erasing characters to be erased, an excellent erasing effect can be obtained with a light force without strongly rubbing the paper. That is,
An excellent erasing effect (erasing performance) can be obtained in which handwriting such as a pencil or a mechanical pencil penetrating into the fibers of the paper surface, that is, graphite, is erased from the paper surface by contacting it with the eraser.

Therefore, according to the present invention, since a reclaimed rubber or a used rubber powder containing no carbon black is used, when erasing a handwriting such as a pencil or a mechanical pencil, a carbon fiber such as a conventional TPE-based eraser is used. There is no danger that the black will transfer to the paper surface and stain the paper surface, and the handwriting can be erased reliably and neatly. Moreover, 60
To provide a rubber-based eraser that is effective for environmental protection, which is expected to have many effects such as longer life than conventional TPE-based erasers because of its excellent heat resistance against a high temperature atmosphere of ℃ to 80 ° C. Can be.

Claims (3)

[Claims] A recycled rubber containing no carbon black;
A rubber-based eraser comprising at least a natural rubber, a synthetic rubber emulsion-based rubber or a polypropylene or polyethylene-based plastic alone or a composite material thereof, a filler, and a eraser. 2. At least at least one of a used rubber powder containing no carbon black, a natural rubber, a synthetic rubber emulsion rubber or a polypropylene or polyethylene plastic alone or a composite material thereof, a filler, and a eraser. A rubber-based eraser characterized by containing. 3. The rubber-based eraser according to claim 1, wherein at least recycled glass powder is contained as a filler.