JP3462924B2 - Degradable writing instrument - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a degradable writing instrument,
For details, by dumping it in the soil or water as waste,
The present invention relates to a lactic acid-based degradable writing instrument that is biodegraded into harmless carbon dioxide gas (CO ₂ ) and water (H ₂ O) by the action of microorganisms in a natural environment like a natural product such as paper or wood and is returned to nature. It is a thing.

[0002]

2. Description of the Related Art In recent years, biodegradable plastics, which have been talked about as one of the answers to the problem of disposal of waste plastics, are in the spotlight. When this biodegradable plastic is dumped in soil or water, it is biodegraded into harmless carbon dioxide gas and water by the action of microorganisms in the soil or water in the natural environment like natural products such as paper and wood. It is attracting worldwide attention as a natural, biodegradable material that is returned to nature.
Its practical application is desired.

[0003]

By the way, writing instruments such as ballpoint pens and felt-tip pens are plastic molded products, but these writing instruments molded using biodegradable plastic are not known. Therefore, when plastic ballpoint pens, felt-tip pens, etc. are no longer needed and are dumped naturally, they remain as debris semi-permanently without being decomposed, which is regarded as a problem in modern society where the need and awareness for environmental conservation are increasing. ing. Therefore, in the past, waste plastics often depended on incineration, and when incinerated, the amount of harmful odors and black smoke (poisonous gas) peculiar to plastics was large, which was a problem. .

The present invention has been made in view of such conventional circumstances, and has strength (material strength) against writing pressure and the like required for writing as a writing instrument, while it is natural when it is discarded as unnecessary. An object of the present invention is to provide a degradable writing instrument that is easily decomposed in an environment and is returned to nature. However, the present inventors have conducted various studies for the purpose of obtaining a writing instrument that can be decomposed in a natural environment like natural products such as paper and wood and has strength against writing pressure at the time of writing. As a result, the present invention has been completed by paying attention to polylactic acid as a biodegradable material capable of adjusting the hardness of material physical properties by controlling the increase or decrease of the molecular weight without impairing the degradability.

[0005]

[Means for Achieving the Object] The technical means taken by the present invention to achieve the above-mentioned object is equipped with a tip opening.
And a cap attached to the tip of the barrel.
A decomposable writing instrument comprising: the barrel, the tip opening
And the cap, with the molecular weight to form a controllable polylactic to 50,000 to 300,000, wherein the cap
The molecular weight of the polylactic acid forming the
That the molecular weight of the polylactic acid that forms the end opening is reduced
Characterize. Another technical means of the present invention is the above shaft.
While molding the cylinder and the above-mentioned tip opening into a rigid type,
It is characterized in that the cap is molded into a soft type.

[0006]

[Operation] Thus, according to the above-mentioned technical means of the present invention, soft to hard polylactic acid can be obtained by controlling the increase or decrease of the molecular weight within the range of 50,000 to 300,000. As a result, the strength required for a writing instrument, especially for writing pressure during writing, can be obtained. On the other hand, when it is no longer needed and is discarded, it is decomposed into harmless carbon dioxide gas and water by the action of microorganisms in the soil and water in the natural environment, and returned to nature just like natural products such as paper and wood. . Moreover, since it is a lactic acid type, it is highly safe.

[0007]

[Example] An example of the implementation of the present invention will be described below.
The polylactic acid used in the present invention is a biodegradable plastic having a composition in which lactic acid is a main material and a highly transparent thermoplastic resin is copolymerized by a chemical reaction,
Controlling the increase or decrease of the molecular weight requires degradability due to the action of microorganisms in soil or water in nature and requires strength as a material, and therefore the molecular weight of polylactic acid is suppressed within the range of 50,000 to 300,000 in the present invention. That is, what is required of the present invention is to have strength against writing pressure at the time of writing, and to maintain both effects of obtaining decomposability in a natural environment. Therefore, the molecular weight is 50,000 to 30. Keep within the range of 10,000.

Lactic acid is obtained by fermenting corn, potato, glucose and the like. As a fermentation method, for example, when corn or potato starch is used as a raw material, first, malt is used to saccharify the starch, and a half amount of C
aCO ₂ is added, and then pure lactic acid bacteria cultured in wort are added and fermented. Furthermore, lime milk is added and boiled until it exhibits weak alkalinity, and after cooling, recrystallized from a small amount of hot water,
Lactic acid can be obtained by adding 50% sulfuric acid to decompose and separating gypsum, and finally evaporating and concentrating the filtrate under reduced pressure. Then, using this lactic acid as a main material, it is possible to obtain polylactic acid which is copolymerized by reacting with a thermoplastic such as polyester and whose molecular weight can be controlled from 50,000 to 300,000.

Next, an example of the implementation of the writing instrument using this polylactic acid will be explained with reference to the drawings. In FIG.
Is a cap, 3 is a tip opening, 4 is a tail plug, 5 is a refill,
These have known shapes.

That is, the barrel 1 and the tip end port 3 are molded with polylactic acid having a molecular weight controlled in the range of 50,000 to 300,000 so that the physical properties of the material are hard type. As a result, the required strength for writing on the barrel 1 and the tip opening 3 is obtained, and the barrel 1 is kept in a linear shaft form without being deformed such as being bent by the writing pressure of the user. Be done. Similarly, the tip opening 3 firmly holds the tip 5-1 of the extra core 5 protruding so as not to rattle during writing pressure. And in the case of the cap 2, it is 50,000 to 30 so that it is a soft type that can obtain appropriate elasticity for the material
Mold with polylactic acid having a controlled molecular weight within the range of 10,000. That is, the molecular weight of polylactic acid is reduced from the molecular weight when the barrel 1 is molded in the opposite manner to the barrel 1. Thereby,
The cap 2 can be mounted in a state in which the cap 2 is in close contact with the tip of the barrel 1 to which the tip port 3 is mounted, and the mounting stability is achieved. Further, the tail plug 4 is molded with polylactic acid having a controlled molecular weight within the range of 50,000 to 300,000.

Of course, the ink tank 5-2 of the refill 5 may be formed of polylactic acid so as to be biodegradable. Also, if the chip 5-1 can be molded, polylactic acid may be used.

Therefore, according to the degradable writing instrument of the present invention,
The molecular weight is controlled to increase or decrease within the range of 50,000 to 300,000. That is, by controlling the copolymerization composition, for example, a polylactic acid capable of varying from a soft type such as polyethylene (PE) to a hard type such as polystyrene (PS) is used as the barrel 1, the cap 2, the tip end opening 3, and the tail plug 4. Since these are molded, the barrel 1 can be molded with a strength (material strength) that is not likely to bend due to a writing pressure or the like required for writing as a writing instrument. Then, the cap 2 can be molded in a state where it has an appropriate elasticity. On the other hand, when it is no longer needed and is dumped in the soil or water, the barrel 1, cap 2, tip end 3, tail plug 4, etc. are natural products such as paper and wood due to the action of microorganisms in the soil and water. Like in the natural environment, it is decomposed into harmless carbon dioxide and water and returned to nature.

[0013]

As described above, the degradable writing instrument of the present invention is formed from polylactic acid capable of varying from a soft type to a hard type by controlling the molecular weight in the range of 50,000 to 300,000. The following operational effects are achieved. While the strength required for writing as a writing instrument is more than sufficient, when it is no longer needed and is thrown away, microorganisms in the soil or water under the natural environment are treated like natural products such as paper and wood. Is decomposed into harmless carbon dioxide gas and water and returned to nature.

Therefore, according to the degradable writing instrument of the present invention,
Since it has the strength (material strength) with respect to the writing pressure at the time of writing required as a writing instrument, it can be put to practical use as a writing instrument. On the other hand, when it is no longer needed and is discarded, it is easily decomposed in the natural environment and returned to nature. Therefore, it is an epoch-making writing instrument that can be said to be one of the answers to the problem of waste disposal of waste plastic, which is regarded as a problem in modern society where the necessity and consciousness for environmental conservation are increasing. Moreover, since it is made of lactic acid, it is a safe and naturally degradable writing instrument. Besides,
You can attach the cap in close contact with the tip, and
The mounting stability of the can be achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of implementation of the degradable writing instrument of the present invention.

[Explanation of symbols]

1… Shaft cylinder 2… Cap 3 ... Tip opening 4 ... Tail plug 5 ... Extra core 5-1 ... Chip 5-2 ... Ink tank

Claims (2)

(57) [Claims] 1. A barrel having a tip opening attached thereto, and the barrel.
Decomposable brush having a cap attached to the tip of
In the writing instrument, the barrel, the tip end opening, and the cap have a molecular weight of 5
Forming a controllable polylactic acid until 10,000 to 300,000
Along with the molecular weight of the polylactic acid forming the cap,
And less than the molecular weight of the polylactic acid forming the tip mouth
Degradable writing instrument, characterized in that it has. 2. A hard type for the barrel and the tip opening.
Along with molding, the cap is molded into a soft type.
The degradable writing instrument according to claim 1, wherein