JPH10265584A - Production of molded product using algae as raw material and its molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely nullify the occurrence of a hazardous substance as chlorine and residue of hazardous substance as heavy metals even when calcination is forced to be done and reduce the production cost for molding. SOLUTION: A polyethylene is selected as a thermoplastic resin and an alga (preferably chlorella) fixed carbon dioxide is selected as a raw material for molding product. The polyethylene resin is crushed to fine particle powder of <=1 mm particle sizes in a low temperature atmosphere, while the alga is used in the form of fine particle powder and they are homogeneously mixed and molded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention particularly relates to the effective use of microalgae, which can be easily industrially mass-cultured, and is effective in reducing and recycling carbon dioxide in the atmosphere.

[0002]

2. Description of the Related Art In recent years, fossil fuels have been consumed in large quantities due to the development of urbanization and industrialization, and the emission of carbon dioxide has been increasing year by year. As a result, the concentration of carbon dioxide in the atmosphere has been increasing due to global warming. Is thought to be one of the causes of Since global warming directly affects the living environment of living organisms, it is urgently necessary to reduce the concentration of carbon dioxide in the atmosphere.

As a method for reducing the concentration of carbon dioxide in the atmosphere, a plant is subjected to a photosynthetic reaction to fix carbon dioxide, and this is mixed with a thermoplastic resin to form a molded body and to recycle it. There is a way to plan. In this case, non-woody plant wastes such as agricultural wastes, forestry wastes or surplus cultures are used as plants, and specifically, straws such as sugarcane meal, straw, rice straw, and jute or other skins. Fibers, leaf fibers such as hemp, or surplus cultures such as chlorella are employed.

[0004]

However, the following problems remain when recycling these resources. 1) The plant is 5 to 70% by weight based on the thermoplastic resin.
Although it is preferable to mix to a certain extent, if the mixing ratio is increased, the tensile strength of the molded article is reduced, and the use of the product is limited. 2) Polyvinyl chloride (PVC) as thermoplastic resin
However, as a deterioration inhibitor (stabilizer), for example, tribasic lead sulfate (TC), dibasic lead stearate (DBL), cadmium, barium, lead fatty acid salt, barium, zinc Fatty acids are used, and additives such as reinforcing fillers, lubricants, plasticizers, etc. are used as necessary, such as the addition of paraffin as a browning inhibitor for products. During the incineration of (cut off materials) etc., harmful substances such as additives, deterioration inhibitors (stabilizers), heavy metals, etc. remain during the generation and burning of chlorine gas, and the treatment is newly performed. Need to be considered.

[0005] The present invention has been made in view of such problems, and achieves the following objects. Prevent the generation of harmful substances such as chlorine even when incineration is required. Eliminate harmful substances such as heavy metals. To reduce production costs when forming molded articles.

[0006]

Means for Solving the Problems A technique of mixing a thermoplastic resin with algae to produce a molded article, selecting a polyethylene resin as the thermoplastic resin, and selecting algae having carbon dioxide fixed as a raw material of the molded article. Adopted. As the polyethylene resin, a polyethylene resin powder whose particle diameter is adjusted to a fine powder of 1 mm or less by pulverization in a low-temperature atmosphere is used. Algae, while drying the carbon dioxide fixed by a photosynthesis reaction, pulverized this dried algae to prepare a fine powdered algal body with a particle size of several μm is used, algal body, Microalgae such as chlorella are selected. Specifically, the polyethylene resin powder and the finely powdered algal body are homogeneously mixed. A homogeneously mixed mixture is filled in a mold and heated and compressed to produce a heat-compressed molded body. As other means, a step of mixing the polyethylene resin in a molten state and algae, a step of pelletizing a mixture of the polyethylene resin and the algae, and a step of filling the pellets in a mold, heating and compressing the molded body, A technique having a molding step is adopted.
A technique is added to take out the molded product from the mold and stabilize the product by applying pressure again and cooling while the molded product is in a plastic state.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

The first embodiment of the method for producing a molded article using algae as a raw material and the molded article according to the present invention are described below.
This will be described with reference to FIG. FIG. 1 shows a manufacturing process of a molded body when chlorella is selected as algae.

[S1: Polyethylene resin] A high-density polyethylene resin (HDPE) is used as the molded article. This polyethylene resin is usually provided in the form of a pellet.

[S2: Lowering the temperature of the resin] The polyethylene resin is supplied to the following steps in a state of being cooled to a temperature of about -20 ° C. Although it is desirable to lower the temperature for efficient pulverization, the pulverization can be performed even if this step is omitted. However, if the temperature is not lowered, it becomes slightly difficult to handle due to adhesion to the surroundings.

[S3: Pulverization of polyethylene resin] The polyethylene resin at room temperature or the polyethylene resin cooled to a lower temperature is appropriately pulverized by a pulverizer or the like and then sieved to have a particle diameter of 1 mm. Only the following fine powders are sorted out. The reason for pulverizing at a low temperature is to reduce the viscosity of the resin to make it easier to pulverize and to prevent the granulation phenomenon of the pulverized particles generated at the time of pulverization. As a technique for pulverizing polyethylene resin, Japanese Patent Application Laid-Open No.
No. 261458, "Method and Apparatus for Producing Fine Particles for Toner" and the like have been proposed. That is, as in this technical example, the raw material powder may be pulverized in the presence of dry ice particles, and the heat generated during the pulverization may be removed by utilizing the vaporization of the dry ice particles.

[S4: Fixation of carbon dioxide] Chlorella of microalgae in a state in which carbon dioxide is fixed by a photosynthesis reaction is applied as a raw material of a molded article.

[S5: Drying of Algae] Chlorella is cultivated in large quantities in a growth vessel or the like, and then dried and weighed to a certain amount to be provided as a block-shaped or pellet-shaped solid.

[S6: Pulverization of Algae] Chlorella in the form of blocks or pellets is pulverized by a pulverizer or the like.

[S7: Finely powdered algal body]
It is prepared into a fine powdery algal body having a particle size of several μm, is stored in a fine powdery algal body supply container or the like, and is supplied to the following steps.

[S8: Mixing (powder / powder)] The fine powder of the polyethylene resin of S3 and the fine algal bodies of S7 are homogeneously mixed at a desired ratio. That is, a powdery mixture is produced. During this mixing, the polyethylene resin and the chlorella are mixed with each other in a fine powder of 1 mm or less, so that the homogenous mixing property is enhanced.

[S9: Heat compression molding] A mixture having a desired ratio is weighed, filled in a mold and heated. The molding temperature at this time is approximately 1 according to the appropriate molding temperature of polyethylene resin.
Set to 60 ° C.

[S10: Removal] During molding, while the molded body is in a semi-solid state, the molded body (semi-molded body) in the middle of molding is removed from the mold.

[S11: Repressurization (Cooling)] The semi-molded product taken out of the mold is loaded into the mold again, repressurized, and cooled as it is to further stabilize the quality of the product.

[S12: Removal] The formed body is removed from the mold and subjected to finishing if necessary to obtain a finished product.

Hereinafter, a second embodiment of a method for producing a molded article using algae as a raw material and a molded article according to the present invention will be described with reference to FIG. FIG. 2 also shows the production of a molded article using chlorella as a raw material as an algae, but as described below, a step of pelletizing a mixture of a polyethylene resin and chlorella is added in the middle.

[S21: Melting of polyethylene resin] A polyethylene resin is used as the molding material. The polyethylene resin is provided in the form of pellets. Here, the polyethylene resin is heated and melted to bring the polyethylene resin into a molten state.

[S22: Microalgae] Chlorella dried and processed into pellets or powders is used.

[S23: Mixing] The polyethylene resin in a molten state and dry chlorella are mixed and kneaded at a high temperature.
Make a homogeneous mixture.

[S24: Cooling] The mixture prepared in S23 is cooled, and a mixture having plasticity is supplied to the next step.

[S25: Pelletizing] A mixture of polyethylene resin and chlorella is pelletized. This pelletization enhances the handleability and homogenous mixing of the polyethylene resin and chlorella.

[S26: Weighing] The amount of pellets necessary for forming the molded body is weighed.

[S27: Heat Compression Molding] The pellets are filled in a molding die, dissolved and molded at a temperature of about 160 ° C.

[S28: Take-out] According to S10, the half-molded body is taken out of the mold.

[S29: Re-pressurization (cooling)] According to S11, the semi-molded body is again loaded in the mold, re-pressurized and cooled, and the quality of the product is stabilized.

[S30: Take-out] The formed product is taken out of the mold and subjected to finishing if necessary to obtain a finished product.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the production of a molded article using algae as a raw material will be described below with reference to FIGS.

FIG. 3 shows the result of measuring the relationship between the molding pressure and the tensile strength of a molded article made of polyethylene resin. The specifications of the molded body are as follows. Material: High density polyethylene resin (HDPE) Molding temperature: 160 ° C Molding time: 2 minutes

As is apparent from FIG.
When changed in the range of 7 MPa, the tensile strength is 24 to
25 MPa, and no remarkable value difference is observed. This means that when the molding pressure is in the range of 1 to 7 MPa, the influence of the molding pressure on the tensile strength of the molded body is extremely small.

FIG. 4 shows the result of measuring the relationship between the molding temperature and the tensile strength of the high-density polyethylene molded body. Moldings used (Sample 1, Sample 2)
Is as follows. [Sample 1 (marked with ○)] Shape of polyethylene resin: pellets Molding pressure: 2.2 MPa Molding time: 2 minutes [Sample 2 (marked with △)] Shape of polyethylene resin: strip Molding pressure: 2.2 MPa Molding time: 2 Minute

As is clear from FIG.
When changed in the range of 0 to 190 ° C., the tensile strength is 2
5 to 26 MPa, and no remarkable value difference is observed. This means that when the molding temperature is in the range of 150 to 190 ° C,
This means that the influence of the molding temperature on the tensile strength of the compact is extremely small.

FIG. 5 shows the result of measurement of the relationship between the content of chlorella and the tensile strength in a molded article of a high-density polyethylene resin and chlorella. The specifications of the molded body are as follows. Raw material: Chlorella (particle size: several μm) Thermoplastic resin: High-density polyethylene resin (particle size: 1 m)
m) Molding temperature: 160 ° C Molding time: 2 minutes Molding pressure: 2.2 MPa

As apparent from FIG. 5, when the chlorella mixture ratio was changed in the range of 0 to 60%, the tensile strength was 2%.
A gradual decrease from 5 MPa to 10 MPa is observed. At this time, no brown change of chlorella due to the heat compression molding was observed.

As described above, the high-density polyethylene resin has a molding pressure of 1 to 7 MPa and a molding temperature of 150 to 190 ° C.
In the range described above, there is almost no effect on the tensile strength. Therefore, the mixing ratio of chlorella may be set according to the tensile strength (desired strength) of the molded article. That is, since a relatively wide range of resin molding conditions can be set, the product can be sufficiently applied to various uses.

[0040]

According to the method for producing a molded article using algae as a raw material and the molded article according to the present invention, the following effects can be obtained. (1) By using polyethylene resin that does not contain chlorine as compared with the case of using vinyl chloride, even if it becomes necessary to incinerate products or scrap materials, generation of harmful substances such as chlorine gas Can be prevented. (2) By lowering the molding temperature to prevent brown (deterioration) of chlorella, a molded article can be formed without using a browning inhibitor (paraffin or the like). (3) Use of additives such as anti-browning agents and stabilizers compared to vinyl chloride by lowering the molding temperature to prevent chlorella degradation and by re-pressing the molded body to stabilize the product. Can be omitted. (4) By mixing a polyethylene resin having a carbohydrate composition and a plant body (carbohydrate) to form a molded body, it is possible to incinerate without leaving harmful substances such as heavy metals in the burning. (5) By directly filling the powdery mixture into a mold and compressing it by heating, it is possible to omit heat mixing and repelletization that require a large amount of thermal energy. (6) By finely pulverizing the thermoplastic resin and the raw material to produce a powdery mixture, the mixture can be uniformly mixed without heating. (7) By mixing the polyethylene resin powder and the fine powdery algal body, the working time at the time of homogeneous mixing can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart of a method for producing a molded article using algae as a raw material according to the present invention, and the steps of an embodiment of the molded article in the first embodiment.

FIG. 2 is a flowchart of a method for producing a molded article using algae as a raw material according to the present invention and a process of implementing the molded article in a second embodiment.

FIG. 3 is a relationship curve diagram between a molding pressure and a tensile strength of a polyethylene resin molded article.

FIG. 4 is a graph showing the relationship between the molding temperature and the tensile strength of a polyethylene resin molded article.

FIG. 5 is a graph showing the relationship between the mixing ratio and the tensile strength when chlorella is mixed.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08L 23/06 C08L 23/06 C12N 1/12 ZAB C12N 1/12 ZABC // B29K 23:00 105: 16 (72) Inventor Masatada Yamashita 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo Foundation of the Institute for Global Environmental Technology (72) Inventor Toshi Otsuki 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo Global Environmental Industry Within the Research Institute of Technology (72) Inventor Takahiro Hirotsu 2217-14 Hayashi-cho, Takamatsu-shi, Kagawa Prefecture Within the Institute of Industrial Technology, Shikoku Institute of Industrial Technology (72) Inventor Hiroshi Kamiya, 2217-14 Hayashi-cho, Takamatsu-shi, Kagawa Prefecture Institute of Industrial Science Shikoku Industrial Technology In-house (72) Inventor Ryoichi Kitagawa 2217-14 Hayashi-cho, Takamatsu-shi, Kagawa Pref.

Claims (9)

[Claims] 1. A method for molding a molded article obtained by mixing algae with a thermoplastic resin, wherein a polyethylene resin is selected as the thermoplastic resin, and carbon dioxide-fixed algae is selected as a raw material of the molded article. A method for producing a molded product using algae as a raw material. 2. The method according to claim 1, wherein the polyethylene resin is pulverized in a low-temperature atmosphere at room temperature or lower to form a fine powder. 3. The method according to claim 2, wherein the polyethylene resin is processed into a fine powder having a particle size of 1 mm or less. 4. The method for producing a molded product using algae as a raw material according to claim 1, wherein the algae to which carbon dioxide is fixed are crushed and processed into fine powdery algal bodies. 5. The method for producing a molded article using algae as a raw material according to claim 1, wherein a chlorella in which carbon dioxide is fixed is selected as the algal body. 6. A step of mixing a polyethylene resin powder and a fine powdery algal body, a step of filling the mixture into a mold, and heating and compressing to produce a molded article; 6. The method for producing a molded product using algae as a raw material according to claim 1, further comprising a step of taking out of the algae and cooling again by pressurizing. 7. A method for molding a molded article obtained by mixing algae with a thermoplastic resin, comprising the steps of: mixing a polyethylene resin and an algae in a molten state; and pelletizing a mixture of the polyethylene resin and the algae. 7. The method for producing a molded article according to claim 1, further comprising the steps of: filling the pellet into a mold, heating and compressing the molded article to form a molded article. 8. An algae characterized by being formed by uniformly mixing a polyethylene resin powder and a finely powdered algal body that has been subjected to a fine powder treatment by fixing carbon dioxide gas by a photosynthetic reaction. Molded body. 9. An algae formed by uniformly mixing a polyethylene resin powder and a microalga such as chlorella in the form of a fine powder, which has been subjected to a fine powder treatment by fixing carbon dioxide by a photosynthetic reaction. The molded article according to claim 7, wherein the molded article is a raw material.