JPH0873613A - Biodegradable protein molded product - Google Patents

Abstract

PURPOSE: To obtain the subject molded product comprising a protein. a decomposition retarder and a water resistance-imparting agent, excellent in the controllability of its flexibility, rigidity, color tone, water resistance etc., and biodegradability, useful as a plastic alternative. CONSTITUTION: This molded product is obtained by incorporating a blend of (A) a protein such as gluten, albumen or gelatin, and (B) a plasticizer such as isostearyl alcohol, polyethylene glycol or sorbitol with (C) a decomposition retarder such as a 8-12C or 12-22C fatty acid triglyceride or an acetylated glycerin fatty acid ester and (D) a water resistance-imparting agent such as a polyhydric alcohol fatty acid ester, a silicone-based water repellent, a fluorine- based water repellent or wax.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable molded article which has excellent strength and is decomposed by microorganisms in soil.

[0002]

2. Description of the Related Art Conventionally, synthetic resins have been widely used as materials for molded articles because they are easy to process, inexpensive, and durable. After being used, such a plastic molded body is incinerated or buried in the soil and discarded, but it has various problems. Plastic incineration produces high calories when incinerated, damages the furnace, produces harmful gases, or remains as it is when buried in the soil, which adversely affects the environment.

Conventionally, various biodegradable protein moldings have been tried in order to solve the problem of such plastic waste treatment, but a substance having a boiling point lower than the molding processing temperature such as water is added. In the foamed molded product obtained by the above process, the thin stretched film is easily broken, and the fragments may impair the commercial value. In addition, studies have been conducted to use a polyol (glycerin or the like) as a plasticizer in order to improve the drawbacks (Japanese Patent Laid-Open Nos. 5-17591 and 5-171049), which gives flexibility. However, the biodegradable plastics made of protein found in the above proposals are almost completely decomposed in soil within a month, so when applied to soil, It will be necessary to slow down the rate of degradability.

The present invention provides a biodegradable protein molded article and a molding material thereof which have appropriate plasticity and can improve the water resistance and can slowly control the rate of biodegradability in soil as required. This is an issue.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention.

That is, by using a plasticizer containing one or more hydroxyl groups in the molecule for producing plasticity, and further adding a glycerin fatty acid ester as a decomposition retarder, biodegradation in soil can be achieved. The required time was degraded within 1 month in the case of the product to which the degradation retarder was not added, while it was extended to 2 to 3 months, and the rate of biodegradability could be controlled slowly.

Further, as a water resistance-imparting agent, a polyhydric alcohol fatty acid ester, a silicone water repellent, a fluorine water repellent,
It has been found that the water resistance is improved by adding one kind of waxes or a combination of two or more kinds. It has been also found that when both the water resistance-imparting agent and the decomposition retarder are blended at the same time, both effects are synergistically improved.

Examples of the protein used in the present invention include gluten, egg white, casein, gelatin and the like. Further, as the plasticizer, monohydric alcohols (octyl alcohol, isostearyl alcohol), polyhydric alcohols (glycerin, polyglycerin, ethylene glycol,
Polyethylene glycol, propylene glycol, pentaerythritol, polypentaerythritol, etc.) and sugars (sorbitol, erythritol, etc.) and the like.

As the decomposition retarder, glycerin fatty acid ester such as medium chain (C8-C12) fatty acid triglyceride, acetylated glycerin fatty acid ester, long chain (C
12-C22) fatty acid triglyceride, medium chain fatty acid (C8
To C12) monoglyceride and the like.

As the water resistance-imparting agent, polyhydric alcohol (glycerin, polyglycerin, ethylene glycol, polyethylene glycol, propylene glycol,
Erythritol, pentaerythritol, polypentaerythritol, etc.) fatty acid esters, silicone water repellents, fluorine water repellents and waxes (polyethylene wax, castor wax, beeswax, paraffin wax,
Microwax, rice wax, etc.).

[0011]

Since the molded product of the present invention exhibits biodegradability, it can solve the problem of processing plastic waste when used as a substitute for plastic. In addition, the flexibility, rigidity and color tone of the molded product can be controlled by changing the ratio, amount, type, combination and processing conditions of the plasticizer / filler, and the possibility as a plastic substitute is expanded. Further, by using the water resistance-imparting agent and / or the decomposition retarder, it becomes possible to increase the water resistance and control the biodegradability rate.

[0012]

EXAMPLES The present invention will be described in more detail by way of examples.

[Biodegradability test] Each compound shown in Table 1 was kneaded with a roll at 30 ° C. for 5 minutes to form a sheet.
It is pressed with a press machine at 150 ° C for 3 minutes to obtain a molded sheet having a thickness of 1 mm. Next, punch the sheet with No. 2 dumbbell,
The punched out biodegradable molded product was buried in soil and the state of decomposition was investigated every week. The results are shown in Table 2.

[0014]

[Table 1]

[0015]

[Table 2]

[Water resistance test] A water resistance was examined by making a molded sheet in the same manner as in the biodegradability test and measuring the contact angle with water. The results are shown in Table 3.

[0017]

[Table 3]

Claims (4)

[Claims] 1. A biodegradable molded article comprising a protein, a plasticizer, and a decomposition retarder and / or a water resistance imparting agent. 2. The biodegradable molded article according to claim 1, wherein the plasticizer has one or more hydroxyl groups in the molecule. . 3. The biodegradable molded article according to claim 1, wherein the decomposition retardant is glycerin fatty acid ester. 4. The water resistance-imparting agent is one selected from polyhydric alcohol fatty acid esters, silicone water repellents, fluorine water repellents, and waxes, or a combination of two or more thereof. The biodegradable molded article according to any one of 1 to 3.