JPH07102114A - Biodegradable composition - Google Patents

Abstract

PURPOSE:To obtain a composition, containing a cellulose ester, starches and a plasticizer at a specific ratio, readily processable into fibers, resins, films, etc., excellent in biodegradability after disposal thereof and safe for the environment. CONSTITUTION:This biodegradable composition contains a cellulose ester, starches and 30-70wt.% plasticizer at (99:1) to (20:80) weight ratio of the cellulose ester to the starches. An additive selected from talc, calcium carbonate, magnesium carbonate, clay, silica, alumina, glass powder, kaolin, mica, wood, cellulose, polyvinyl alcohol, chitin, chitosan, collagen, fibroin and keratin may be blended with the biodegradable composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellulose ester composition which can be easily molded into fibers, resins and films and has excellent biodegradability.

[0002]

2. Description of the Related Art In recent years, synthetic fibers, synthetic resins, and films have been widely used for various purposes because they are inexpensive and have excellent durability and mechanical strength.

However, when these molded products are discarded in the natural world, they remain undecomposed and remain as they are, causing environmental pollution, and thus they are attracting attention as a serious social problem.

In order to solve the above problems, it is necessary that the molded product be biodegraded by microorganisms existing in soil or water, and the development of a composition capable of adjusting the biodegradation rate has been advanced. ing.

For example, Japanese Unexamined Patent Publication (Kokai) No. 4-142344 discloses a synthetic resin material prepared by mixing a cellulose ester with a plasticizer and a polyester. The synthetic resin material is disclosed in page 5, lower right column, page 5 of the publication. As described in line 6 of the same line, it takes a long period of time from 1 year to 5 years until a molded article with a thickness of 1 mm collapses and no small part can be found. From the viewpoint of prevention, it is hard to say that it has sufficient biodegradability.

On the other hand, JP-A-5-32822, JP-A-4-353537, or JP-A-4-2488.
Japanese Patent No. 51 discloses a biodegradable biocomposition obtained by blending an ethylene-vinyl alcohol copolymer or an aliphatic polyester with starch.

[0007] However, the composition has a defect that the moldability and the physical properties are inferior because of poor compatibility of the starch with the ethylene-vinyl alcohol copolymer or the aliphatic polyester which is the compounding object. .

That is, hitherto, no formulation of a resin composition excellent in biodegradability in a short period of time has been proposed without deteriorating moldability and physical properties.

[0009]

The object of the present invention is to solve the above-mentioned problems of the prior art and to enable easy molding into fibers, resins, films, etc., and to exhibit excellent biodegradability. To provide a composition.

[0010]

Means for Solving the Problems As a result of intensive investigations by the present inventors to achieve the above object, when a novel compounding composition of cellulose ester and starch excellent in compatibility with the cellulose ester is adopted, It was determined that the desired biodegradable resin composition can be obtained.

Thus, according to the present invention, there is provided a biodegradable composition containing cellulose ester, starch and a plasticizer, wherein the content of the plasticizer in the biodegradable composition is 30 to 30.
There is provided a biodegradable composition, which is 70% by weight and a weight ratio of cellulose ester and starch is 99: 1 to 20:80.

The constituent features of the present invention will be described in detail below. The cellulose ester used in the present invention is one in which a part or all of the hydroxyl groups of cellulose are substituted with ester groups, and examples thereof include cellulose diacetate, cellulose triacetate, and cellulose acetate butyrate.

These cellulose esters may be used alone or in combination of two or more kinds.

As the starches to be added to the above cellulose ester, corn, wheat, potato,
In addition to raw starch obtained from rice, tapioca, sweet potato, etc.,
Examples include physically modified starch such as α-starch, enzyme-modified starch such as dextrin and amylose, chemically modified starch such as oxidized starch, or ester derivative such as esterified starch, etherified starch and cross-linked starch. To be done.

In the present invention, it is essential that the cellulose ester and the starch are blended in a weight ratio of 99: 1 to 20:80.

When the weight ratio of the cellulose ester exceeds 99, the biodegradation rate becomes too slow to be put to practical use. On the other hand, when the weight ratio is less than 20, not only the moldability is deteriorated but also the biodegradation is caused. The speed becomes too fast and the composition becomes unstable.

The blending ratio of cellulose ester and starch may be appropriately set within the above range depending on the desired biodegradation rate, and the biodegradation rate becomes slower as the blending amount of cellulose ester increases.

The plasticizer used in the present invention may be any biodegradable one, and the following are exemplified.

(1) Organic acid esters Aromatic esters such as phthalic acid esters, natural fats and oils, monoglycerides, diglycerides, fatty acid esters, cyclic esters such as caprolactone, oligomers such as adipic acid-ethylene glycol oligomers and the like. (2) Sugar ester sorbitol butyrate, mannitol acetate propionate, etc. (3) Organic acids Saturated fatty acids such as lactic acid, citric acid, caproic acid, tartaric acid,
Unsaturated fatty acids such as fumaric acid and oleic acid, and aromatic acids such as phthalic acid. (4) Others In addition to glycols such as ethylene glycol, propylene glycol, tetramethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, glycerin, diglycerin, triethyleneimine, triethanolamine, sulfolane, dimethoxyethyl adipate, ethyl cellosolve. , Methyl cellosolve, triethylene glycol acetate, caprolactam, etc.

Here, the amount of the plasticizer used should be 30 to 70% by weight based on the total weight of the composition containing the cellulose ester, the starch and the plasticizer.

When the amount of the plasticizer exceeds 70% by weight, the resulting composition becomes unstable, while when it is less than 30% by weight, the compatibility between the cellulose ester and starch is deteriorated and the moldability is deteriorated. The plasticizers may be used alone or in combination of two or more.

In the composition of the present invention, in addition to the above components, talc, calcium carbonate, magnesium carbonate, clay, silica, alumina, glass powder, kaolin, mica, wood,
At least one additive selected from the group consisting of cellulose, polyvinyl alcohol, chitin, chitosan, collagen, fibroin, and keratin may be blended.

By adding the above-mentioned additives, various properties including mechanical properties such as strength can be improved. However, if the amount of the additive is too large, the moldability decreases, so it is preferable to limit the content to 50% by weight at most.

In addition to the above, the composition of the present invention may contain a stabilizer, a modifier and the like within a range that does not impair the object of the present invention.

Since the composition of the present invention thus obtained has good moldability, it can be molded into an arbitrary shape such as a resin molded product, a film or a fiber, and the molded product thus obtained. Shows excellent biodegradability.

[0026]

In the present invention, by adopting a novel compounding composition of cellulose ester and starch, the moldability of the composition is improved and the excellent biodegradability is exhibited.

That is, since the compatibility between the compound and the compound is improved by compounding the compound having the same structure as the basic skeleton of the compound, the influence of the plasticizer should be minimized. The properties inherent to each component are synergistically exhibited.

In the composition of the present invention, the cellulose ester mainly controls the moldability and the starch mainly controls the biodegradability. By combining these two, good moldability and excellent biodegradability are obtained. A composition having properties is obtained.

The present invention will be described in more detail below with reference to examples. The physical properties shown in the examples are measured by the following methods.

(1) Formability Using a melt spinning machine equipped with a circular single-hole spinning spinneret having a hole diameter of 0.75 mmφ, the pelletized composition was subjected to a spinneret temperature of 220 ° C.
When a monofilament having a diameter of 0.4 mm was obtained by discharging at 1., the spinnability was judged in the following 4 stages and used as a measure of formability. A: Spinning is possible without any problems B: Spinning is possible although a slight coloration is observed C: Spinning frequently occurs and spinning is difficult D: Composition is significantly decomposed and spinning is impossible

(2) Biodegradability A monofilament with a diameter of 0.4 mm was embedded in the soil collected at the Osaka Research Center, Teijin Ltd., 3-4-1 Mihara, Ibaraki City, Osaka Prefecture, and the temperature was raised to 30 ° C. It was kept for 3 months under sufficient humidity, and the degree of decomposition was evaluated according to the following 4 grades. a: Almost decomposed and filament shape cannot be confirmed b: Shape can be confirmed but severely damaged c: Part of filament is damaged d: Almost no decomposition

[0032]

Example 1 Cellulose diacetate flakes, potato starch and the plasticizers shown in Table 1 were mixed in a predetermined amount, and then,
Kneading and extrusion were performed using a screw type extruder to obtain pellets.

The pellets thus obtained are treated with a hole diameter of 0.75 mmφ.
Using a melt spinning machine equipped with a circular single-hole spinning spinneret, the spinneret was discharged at a spinneret temperature of 220 ° C. to obtain a monofilament having a diameter of 0.4 mm.

The moldability in obtaining the monofilament and the biodegradability of the obtained monofilament are shown together in Table 1.

[0035]

[Table 1]

[0036]

Example 2 Example 1 was repeated except that the type of plasticizer was changed as shown in Table 2.

Table 2 shows the moldability in obtaining the monofilament and the biodegradability of the obtained monofilament.

[0038]

[Table 2]

[0039]

Example 3 The procedure of Example 1 was repeated except that the additives shown in Table 3 were added.

Table 3 shows the moldability in obtaining the monofilament and the biodegradability of the obtained monofilament.

[0041]

[Table 3]

[0042]

Industrial Applicability According to the present invention, there is provided a cellulose ester composition which can be easily molded into fibers, resins, films and the like and has excellent biodegradability.

Claims (2)

[Claims] 1. A biodegradable composition comprising cellulose ester, starch and a plasticizer, wherein the content of the plasticizer in the biodegradable composition is 30 to 70% by weight, and the cellulose ester and the starch. Weight ratio of 99: 1 to 2
A biodegradable composition, which is 0:80. 2. The biodegradable composition comprises talc, calcium carbonate, magnesium carbonate, clay, silica, alumina,
The biodegradable composition according to claim 1, which is a composition containing at least one additive selected from the group consisting of glass powder, kaolin, mica, wood, cellulose, polyvinyl alcohol, chitin, chitosan, collagen, fibroin and keratin. Composition.