JP2001031134A - Biodegradable film and biodegradable bag using the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat raw refuse and feces and urine together with a bag and to prevent bad odor from being generated by incorporating active carbon in a biodegradable film. SOLUTION: As a biodegradable plastic used for a biodegradable film, polylactic acid, polyhydroxyalkanoate, lactone resins, aliph. polyester resins such as polyesters obtd. from a low mol. wt. aliphatic dicarboxylic acid and a low mol. wt. aliphatic diol, modified starch, modified polyvinyl alcohol composite, etc., are used. In addition, this biodegradable plastic is melted and kneaded with active carbon prepd. by using kenaf as a raw material and the mixture is pelletized and a film is prepd. by using the obtained pellet and a biodegradable bag is produced by using the obtained biodegradable film. The compounding ratio of the biodegradable plastic and the active carbon is not restricted but the active carbon is restricted in a range of 2-70 wt.% to the biodegradable plastic, pref. 5-30 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a biodegradable film and a biodegradable bag using the same.

[0002]

2. Description of the Related Art In recent years, how to treat garbage from homes has become a major problem. As such a treatment method, techniques have been developed, such as decomposing garbage into water and carbon dioxide using microorganisms, or making compost from garbage by the action of microorganisms. In this case, the garbage is once put in a bag and then transferred to a container where microorganisms are present. However, since bags such as polyethylene cannot be decomposed by microorganisms, only garbage must be newly transferred to the container. This transfer is not only time-consuming, but also foul-smelling and unsanitary.

[0003] Also, for example, manure produced by animals in the zoo,
The method has been adopted in which manure is once collected in a container, then transported to a treatment plant, taken out of the container and processed. However, the work of removing manure from a container requires not only a great deal of labor, but also odor problems and hygiene problems, and has several problems to be solved.

[0004] In order to solve such a problem, there is a method in which a biodegradable bag is used as a bag to be used for these purposes, and the bag is treated as a whole. However, even with such a method, there still remains a problem of a bad smell emitted when the bag is decomposed and the contents in the bag are mixed into the soil or the like.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems at once, and is capable of treating garbage and manure together with bags and reducing biodegradability. It is intended to provide a film and a biodegradable bag.

[0006]

Means for Solving the Problems The biodegradable film of the present invention is characterized by containing a biodegradable plastic and activated carbon.

A biodegradable film characterized in that the activated carbon is made of kenaf.

Further, a biodegradable bag of the present invention comprises the above biodegradable film.

[0009]

Embodiments of the present invention will be described below.

The biodegradable plastics used in the biodegradable film of the present invention include polylactic acid, polyhydroxyalkanoate, lactone resin, and fatty acids such as polyester obtained from low molecular weight aliphatic dicarboxylic acid and low molecular weight aliphatic diol. Aromatic polyester resin, modified starch or modified polyvinyl alcohol complex etc. can be used,
Aliphatic polyesters are particularly preferably used from the viewpoints of film moldability, processed physical properties, and biodegradability.

Next, the raw materials of the activated carbon used in the present invention include wood, charcoal, coal, coconut shell, lignin, pulp waste liquor, molasses, kenaf, coffee bean husk, and the like. Activated and purified. In particular, activated carbon made from kenaf is suitably used from the viewpoint of the rate of removing the components causing the bad smell and the amount of adsorption.

Although the size of the activated carbon cannot be determined unconditionally depending on the thickness of the film, it is desirable that the particle size is in the range of 1 to 2000 μm, preferably 10 to 500 μm.

The mixing ratio of the above-mentioned biodegradable plastic and activated carbon is such that the ratio of activated carbon to biodegradable plastic is 2 to 2.
It is set in the range of 70% by weight, preferably 5 to 30% by weight. By setting the blending ratio of activated carbon to 2% by weight or more, a performance excellent in deodorizing effect at the time of biodegradation is exhibited.
When the content is not more than the weight%, a film excellent in mechanical properties such as strength and elongation can be obtained.

In the present invention, auxiliary components such as an antioxidant, a colorant, a release agent, an antistatic agent, an inorganic filler, a lubricant, an antiblocking agent, and a surfactant can be added.

Next, a specific method for producing the biodegradable film of the present invention will be described. First, activated carbon is melt-kneaded with a biodegradable plastic and pelletized. For this operation, a well-known kneading device such as a Banbury mixer, a Henschel mixer, a single-axis kneader, a multi-axis kneader, a mixing roll, or a kneader is suitably used.

Next, a film is formed using the obtained pellets. In forming the film, a known melt extrusion molding method can be used. The processing method preferably used is, for example, molding by a T-die method and an inflation method. Further, if a stretching step is added simultaneously with or after the film formation, the mechanical properties thereof can be further improved. As the stretching method, a known stretching method such as a roll stretching and a tenter method can be used.

Further, the biodegradable plastic is formed into a film by the above method without melting and kneading the activated carbon, and then the activated carbon is sprayed on the film surface and heat-fused to obtain a biodegradable film containing the activated carbon. You can also.

The thickness of the biodegradable film is appropriately set according to the strength required in accordance with the use to be used. However, the thickness of the biodegradable film is usually used for bags such as manure bags and sowing bags for soil greening. 100-2000 μm, compost bag,
10 for garbage bags, shopping bags and various packaging films
Generally, it is set between 500 μm.

Using the biodegradable film thus obtained, a biodegradable bag is manufactured. Here, as a method of manufacturing the biodegradable film of the present invention in a bag shape, two or three sides of the biodegradable film of the present invention are stacked and heat-sealed in two or three directions, or the film is formed in a tubular shape. In this case, it is common to form a bag by a known bag-making method such as heat-sealing the bottom portion.

When the biodegradable film of the present invention produced by the above method and the biodegradable bag using the same are filled with, for example, garbage or manure, the bag is left in a natural environment in the soil. The malodors decomposed and released by the ones in the bag are significantly reduced as compared to those made from biodegradable plastic alone. In addition, as for biodegradability, the decomposition rate can be increased as compared with the case where biodegradable plastic is used alone. This means that when the film is cracked by microorganisms and the decomposition of the polymer starts, the activated carbon mixed in is lost in the soil. Therefore, the film is disintegrated faster than that produced by using the biodegradable plastic alone, so that the biodegradability is improved. Further, if garbage or manure in the bag subsequently mixes into the soil, an odor is generated. At this time, the activated carbon scattered in the soil efficiently absorbs the odor.

Furthermore, even if activated carbon finally remains in the soil, it does not affect the environment.

[0022]

The biodegradable film and the biodegradable bag of the present invention contain a biodegradable plastic and activated carbon.
Garbage and manure can be processed together with the bag, and the odor is significantly reduced.

In particular, by using kenaf as a raw material as the activated carbon, a component causing a bad odor can be quickly absorbed, and its performance can be maintained for a long period of time.

In addition, the biodegradability can be increased as compared with the biodegradable plastic produced alone.

Furthermore, since activated carbon does not affect the environment even if it remains in the soil, it is useful from the viewpoint of protecting the global environment.

Claims (3)

[Claims] 1. A biodegradable film comprising a biodegradable plastic and activated carbon. 2. The biodegradable film according to claim 1, wherein said activated carbon is made of kenaf. 3. A biodegradable bag comprising the biodegradable film according to claim 1.