JP3587431B2 - eraser - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a plastic eraser having excellent bending strength and good erasing properties.
[0002]
[Prior art]
Erasers for erasing handwriting of pencils and mechanical pencils include rubber-based ones consisting of natural rubber, synthetic rubber, and sub-plastics, and plastic resins such as vinyl chloride, polyvinyl chloride, and other plastic resins and plasticizers. There are plastic-based erasers, but plastic-based erasers have been widely used in the past because they are superior in moldability, erasability, stability and the like as compared with rubber-based ones.
[0003]
The reason that this type of eraser can erase the handwriting of a pencil or mechanical pencil is that when the handwriting is rubbed with the eraser, the abrasion powder of the core that forms the handwriting is removed from the paper surface by re-adhering to the eraser surface or the surface of the eraser debris. That is, the high flexibility of the plastic eraser is a major factor contributing to excellent erasability. Therefore, in order to obtain good erasability, it is necessary to form a plastic eraser flexibly.However, a plastic eraser having a high flexibility has a drawback that its bending strength is weak. Since it is easily chipped, it is difficult to apply it to a replacement eraser such as a mechanical pencil.
[0004]
[Problems to be solved by the invention]
Attempts have been made to increase the strength of the eraser without impairing the erasability of the eraser. For example, an eraser in which a reinforcing material such as fine fibers is blended with an eraser substrate (Japanese Patent Publication No. Sho 62-47720, Japanese Patent Laid-Open No. 5,131,795, Japanese Utility Model Application Laid-Open No. 5-80790, and the like, in which a polymerizable vinyl monomer is blended with a base material mainly composed of a resin and a plasticizer to form a polymer having a network structure inside (Japanese Patent Publication No. Hei 3- No. 57123), a plurality of types of erasers having different hardnesses are dispersed and integrated into particles (Japanese Patent Publication No. 8-5275), or an inorganic material, a binder, a piercing agent and the like are formed as raw materials. A self-wearing porous material impregnated with a plastic sol and gelled by heating (Japanese Patent Laid-Open No. 8-258493) is known.
[0005]
However, in each of the above-mentioned plastic erasers, since the soft eraser rich in erasability is distributed substantially evenly over the inside and the entire surface of the eraser, stress is concentrated when the eraser is formed into a thin rod shape. Cracks are likely to occur on the outer peripheral surface, and the cracks easily spread to the inside, so that it is difficult to achieve the intended purpose.
[0006]
In view of the above problems, an object of the present invention is to provide a plastic-based eraser having excellent bending strength and good erasability.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the present invention, a thin rod composed of a soft eraser excellent in erasability and a hard eraser excellent in strength both having a plastic resin and a plasticizer as main components. An eraser having a shape, wherein a hard eraser and a soft eraser each extend continuously over the entire length of the thin rod shape, and wherein the hard eraser has a cylindrical outer shell wall, and and connecting the inner peripheral surface of the shell wall forms a partition wall for partitioning the inside of the shell wall into a plurality of chambers, anti-shaped material of the soft surrounded by the outer shell wall and the partition wall It is characterized in that each room is filled and integrally formed.
[0008]
According to the above configuration, the soft erasure material excellent in erasing properties and the hard erasure material excellent in strength each extend continuously over the entire length of the thin rod shape. A soft eraser material having excellent eraseability can be directly adhered to the handwriting of a pencil or mechanical pencil and rubbed. On the other hand, the hard eraser material with strong strength extends continuously over the entire length of the thin rod shape and forms an outer shell wall that reinforces the outer peripheral surface of the thin rod shape over the entire circumference, so that the soft eraser material is used. A hard eraser material having excellent strength can be used to reinforce the eraser, particularly the outer peripheral portion, while ensuring excellent eraseability. Therefore, it is possible to provide a plastic eraser that is resistant to bending and bending and has excellent erasing properties.
[0009]
In addition, since the hard eraser material having excellent strength forms a partition connecting the cylindrical outer shell wall and the inner peripheral surface thereof over the entire length of the thin rod shape , the excellent eraser material having a soft eraser material extends over the entire length. Soft erasure material with excellent erasability can be protected and reinforced with a cylindrical outer shell wall made of hard erasure material while securing the character characteristics, especially on the outer periphery of a thin rod-shaped eraser. It is possible to obtain a structure in which cracks are not easily generated, and it is possible to obtain a tough outer shell and a thin rod-shaped eraser having a skeleton reinforcing structure.
[0010]
Preferably, the partition has a wall structure having a substantially cross-shaped cross section.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
【Example】
1 and 2 show an embodiment of the eraser according to the present invention. Referring to these figures, the eraser of this embodiment has a slender cylindrical shape as a whole, and both a hard eraser 1 and a soft eraser 2 mainly composed of a plastic resin and a plasticizer. Each extends continuously over the entire length. The hard eraser 1 forms a cylindrical outer shell wall 1a and a partition wall 1b having a substantially cross-shaped cross section connecting the inner peripheral surfaces of the cylindrical outer shell wall 1a over the entire length of the outer shell wall 1a. The soft eraser 2 is filled between the outer shell wall 1a and the partition 1b over the entire length of the eraser, and is formed integrally with the outer shell wall 1a and the partition 1b. The hard and soft eraser materials 1 and 2 in the eraser have almost the same cross-sectional shape at any point in the length direction.
[0013]
Hard and soft eraser materials 1 and 2 are made by mixing a plasticizer with a plastic resin, adding fillers, stabilizers, pigments, fragrances, etc. as needed, and uniformly stirring and mixing. By doing so, it is gelled and integrally molded. As the plastic resin base material, vinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, etc. used in general plastic erasers can be used. The plasticizer can be appropriately selected from, for example, dioctyl phthalate, dinonyl phthalate, dioctyl azelate, dioctyl adipate and the like. Commonly used calcium carbonate, magnesium carbonate, silicic acid powder, and the like can be used as the filler. The hardness of the erasing materials 1 and 2 and the ease with which erased chips are generated can be adjusted by appropriately adjusting the mixing ratio of these components. Further, the eraser in the form of a thin rod composed of the hard eraser 1 and the soft eraser 2 can be integrally molded while being simultaneously extruded by an extruder.
[0014]
In an eraser using a plastic resin as a base material, as shown by a solid line in FIG. 3, the erasability and the strength (hardness) of the erasure material are opposite to each other. However, according to the configuration of the present invention, for example, in FIG. 3, the soft eraser 1 having the characteristic of the point A and the hard eraser 2 having the characteristic of the point B are combined and integrated, thereby substantially An eraser having the characteristics (strength and erasability) of the upper point C can be obtained.
[0015]
As can be seen from FIG. 1, the soft eraser 2 is exposed on the end surface of the eraser in the form of a thin bar. When the eraser is rubbed over the handwriting of a pencil or a mechanical pencil, the soft eraser 2 is drawn on the handwriting. The soft erasing material can exert the excellent erasing ability of the soft erasing material as much as possible. Further, since the hard erasure material 1 also has an appropriate erasure property, the hard erasure material 1 does not hinder the erasure of handwriting.
[0016]
【The invention's effect】
As is clear from the above description, according to the present invention, while securing excellent erasure properties by a soft erasure material over the entire length, and securing erasure properties by a hard erasure material, It is possible to provide a thin rod-shaped eraser having a simple outer shell reinforcing structure or a skeleton reinforcing structure.
[Brief description of the drawings]
FIG. 1 is a perspective view of an eraser showing one embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a main part of the eraser shown in FIG.
FIG. 3 is an explanatory diagram showing the erasure and strength characteristics of the eraser shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hard eraser 1a Outer shell wall 1b Partition wall 1c Cross wall 1d Plate-like wall 2 Soft eraser

Claims (2)

Both are thin rod-shaped erasers composed of a soft eraser excellent in erasability and a hard eraser excellent in strength mainly composed of a plastic resin and a plasticizer. erasing shaped material softer extends continuously over the entire length of the thin rod-shaped respectively, and an outer shell wall vanishing shaped material is cylindrical rigid, and connects the inner peripheral surface of the shell wall the A partition partitioning the interior of the outer shell wall into a plurality of rooms is formed, and the soft eraser is filled in each room surrounded by the partition and the outer shell wall to be integrally formed. An eraser characterized in that: 2. The eraser according to claim 1, wherein the partition has a wall structure having a substantially cross-shaped cross section.

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