JP2000095898A - Biodegradable material modifier, and biodegradable material composition using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject modifier consisting of an epoxidized polyisoprene and capable of giving inexpensive biodegradable material compositions improved in molding processability, extensibility and brittleness. SOLUTION: This modifier is such one as to consist of an epoxidized polyisoprene(pref. epoxidized cis-1,4-polyisoprene 5-75 mol% in epoxidation degree) which is obtained, preferably by epoxidation of the C=C double bonds of natural rubber or a polyisoprene containing >=90% of cis-1,4-bond which is produced by polymerization of isoprene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biodegradable material modifier comprising epoxidized polyisoprene, and a biodegradable material composition using the epoxidized cis polyisoprene as a biodegradable material modifier. About things.

[0002]

2. Description of the Related Art Environmental pollution due to plastic waste has become a problem due to global environmental problems. To avoid that,
Various biodegradable materials are being considered. Cellulose and starch conventionally known as biodegradable materials have a problem that they cannot be thermoformed because they are not thermoplastic, and partially acetylated cellulose and partially acetylated starch have been proposed as a method of improving this problem. . However, these have difficulty in moldability such as high molding temperature of 190 to 240 ° C. and high melt viscosity.
Another disadvantage is that the resin is hard and brittle. In the case of starch, there is a disadvantage that the moisture resistance strength is low.

[0003] In addition, aliphatic polyesters, which are biodegradable materials, also have a high molding temperature, have a problem of moldability, and have low elongation at break, and are hard and brittle, so their applications are limited. To improve these, various plasticizers such as phthalic acid esters have been blended. However, the blending of the plasticizer may cause bleeding on the surface of the molded product, causing undesirable phenomena such as giving the molded product a sticky feeling.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive modifier which can improve the moldability of a biodegradable material. Another object of the present invention is to provide a biodegradable material composition having improved moldability by blending a biodegradable material with a modifier. It is a further object of the present invention to provide a biodegradable material composition with improved elongation and brittleness of the biodegradable material.

[0005]

Means for Solving the Problems The present invention provides the following (1) to
An invention having the constitution (4), and the above object is achieved by these inventions. (1) A biodegradable material modifier comprising epoxidized polyisoprene. (2) A biodegradable material composition obtained by mixing a biodegradable material and an epoxidized polyisoprene. (3) A biodegradable material composition obtained by mixing a biodegradable material, an epoxidized polyisoprene, and a crosslinking agent. (4) An epoxidized polyisoprene composition containing a crosslinking agent. Hereinafter, the present invention will be described in detail, which will clarify other objects, advantages, and effects of the present invention.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The modifier incorporated in the biodegradable material of the present invention comprises epoxidized polyisoprene.
Among the epoxidized polyisoprenes, epoxidized trans-1,4-polyisoprene and epoxidized cis-1,4-polyisoprene are preferable, and epoxidized cis-1,4-polyisoprene is particularly preferable. Epoxidized cis-1,4
-When polyisoprene is used, the object of the present invention is more excellently achieved, and excellent effects are exhibited.

Among the epoxidized polyisoprenes, epoxidized cis-1,4-polyisoprene has 9 cis-1,4 bonds obtained by polymerizing natural rubber or isoprene.
Polyisoprene containing 0% or more, preferably 95% or more is used as a raw material, and carbon-carbon double bonds of natural rubber or polymerized polyisoprene are epoxidized. As the raw material natural rubber, a commercially available natural rubber latex containing a surfactant, ammonia or the like for stabilizing a natural rubber latex obtained from a natural rubber tree, or a natural rubber obtained by coagulating a natural rubber latex can be used. . Further, cis-1,4-polyisoprene obtained by solution polymerization or the like is converted into hydrogen peroxide and a phase transfer catalyst in an organic solvent,
Epoxidized cis-1,4-polyisoprene can also be obtained by oxidation with hydrogen peroxide and an organic acid or an organic peroxide. Also, after dissolving the polymerized polyisoprene in a solvent, redispersing and re-emulsifying, and further using a polyisoprene latex in which the solvent is replaced with water, the epoxidized cis-1,4-polyisoprene is oxidized by latex. Can also be obtained as The raw material cis-1,4-
As the polyisoprene, those having a weight average molecular weight of 5,000 to 3,000,000, particularly 20,000 to 3,000,000 in terms of polystyrene measured by gel permeation chromatography are used. Is preferred.

[0008] As described above, the above-mentioned raw materials are epoxidized using an oxidizing agent, whereby the epoxidized cis-1,4-epoxide is obtained.
Polyisoprene can be obtained, and can be obtained as a latex if desired. As the oxidation method such as the type and amount of the oxidizing agent and other oxidation conditions, a method known per se can be used. The degree of epoxidation is preferably from 5 to 75 mol%, more preferably from 15 to 50 mol%. Such epoxidized cis-1,4-polyisoprene is commercially available and can be obtained at low cost.
Here, the epoxidation degree is a value based on the amount of carbon-carbon double bonds contained in the raw material natural rubber or polymerized polyisoprene. As described above, epoxidized cis-1,4-polyisoprene has been described. Epoxidation from a polyisoprene other than cis-1,4-polyisoprene is possible in the same manner, and in this case, the molecular weight range described above is preferable. .

In the following description, an example in which epoxidized cis-1,4-polyisoprene is used as a modifier will be described. The biodegradable material composition of the present invention,
Epoxidized cis-1,4-biodegradable material and modifier
It is obtained by mixing with polyisoprene. The biodegradable material is not particularly limited, but is preferably a natural polymer or a synthetic polymer. Specifically, cellulose, partially acetylated cellulose, partially sulfonated cellulose, partially phosphorylated cellulose, partially cationized cellulose, partially alkylated cellulose, partially hydroxylated cellulose,
Partially carboxylated cellulose, starch, partially acetylated starch, partially sulfonated starch, partially phosphorylated starch, partially hydroxylated starch, partially carboxymethylated starch, partially alkylated starch, partially benzylated starch, partially cyanoethylated starch, partially cation Starch, chitin, partially cyanoesterified chitin, chitosan, polyamino acid, alginic acid, aliphatic polyester and the like.

As the above-mentioned cellulose, for example, commercially available pulp (cellulose fiber), waste paper, sugarcane scum (bagasse),
Wood flour, cottonseed cellulose, bacterial cellulose, trees,
Examples include, but are not limited to, pulverized plant and bamboo, paper obtained by adding inorganic fillers and various chemicals using cellulose as a raw material, and recovered paper obtained by collecting them. Particularly preferred is paper in which cellulose and an inorganic filler are dispersed. The mixture of the paper fiber containing 5 to 15% of water and the epoxidized cis-1,4-polyisoprene is better than the mixture of the cellulose alone and the epoxidized cis-1,4-polyisoprene. A stronger mixture can be obtained.

Examples of the above starch include corn starch, waxy corn starch, wheat starch, tapioca starch, potato starch and the like.

The modified cellulose or starch preferably has a degree of substitution of 2 or less from the viewpoint of biodegradability.
Here, the degree of substitution refers to the three hydroxyl groups of the glucose skeleton.
It is the number of substituted hydroxyl groups.

As the polyamino acid, homopolymers or copolymers of amino acids such as glutamic acid, aspartic acid and lysine can be used. Examples of the aliphatic polyester include microorganisms such as polylactic acid; 3-hydroxybutyrate, 3-hydroxyvalerate, 4-hydroxybutyrate, 3-hydroxyalkanoate, 3-hydroxycaprolate, and 3-hydroxyheptanoate. A homopolyester or copolyester obtained by polycondensation of a hydroxyl group-containing ester compound which can be produced by utilizing polyglycolic acid, polybutylene succinate, polybutylene succinate adipate,
Polycaprolactone, polypropiolactone, polyhydroxybutyrate, polybivalolactone, such as a homopolyester or copolyester obtained by polycondensation of a monomer produced by a synthetic reaction without using microorganisms such as polyglycolide. it can.

In the case of the aliphatic polyester, it is extremely compatible with the epoxidized cis-1,4-polyisoprene.
A small amount of mixing lowers the processing temperature and can give the molded product flexibility. Moreover, it maintains transparency and is, of course, biodegradable. Further, a mixture of cellulose fibers or crushed chips with epoxidized cis-1,4-polyisoprene, preferably epoxidized polyisoprene latex, and a crosslinking agent described below can be thermoformed, and after molding,
Further heat treatment shows high mechanical strength and does not impair biodegradability.

By mixing such a biodegradable material with an epoxidized cis-1,4-polyisoprene as a modifier, a functional group present in the biodegradable material reacts with an epoxy group to form a covalent bond. Or a weak bond is formed by the interaction between the functional group and the epoxy group, so that the processability of the biodegradable material, which was originally difficult to form by heating, is significantly improved by heating. . In addition, the properties such as elongation and brittleness of the biodegradable material are improved along with the improvement of the moldability. And the resulting composition is biodegradable.

The epoxidized cis-1,4-polyisoprene is used in an amount of 3 to 30 parts by weight based on 100 parts by weight of the biodegradable material for those exhibiting thermoplasticity such as aliphatic polyester, acetylated cellulose and acetylated starch. Parts, more preferably 5 to 20 parts by weight. In the case of non-thermoplastic materials such as cellulose, starch, chitin, chitosan, and polyamino acids or those whose molding temperature and pyrolysis temperature are close to each other and which are difficult to process as a thermoplastic polymer, epoxidized cis-1,4 -Polyisoprene is 10 to 20 parts by weight per 100 parts by weight of the biodegradable material.
0 parts by weight, more preferably 20 to 100 parts by weight are mixed.

When the biodegradable material has a functional group capable of forming a covalent bond by reacting with an epoxy group, a compound for accelerating the reaction can be preferably used. Also, even if the epoxy group and the functional group of the biodegradable material do not directly react to form a covalent bond, mixing the compound allows the functional group of the compound and the functional group of the biodegradable material to be mixed. Reacts with each other to form a covalent bond, and the functional group of the compound reacts with the epoxy group of the epoxidized cis-1,4-polyisoprene to form a covalent bond. And epoxidized cis-1,4-polyisoprene strongly bind to each other, and it is extremely preferable to mix such a compound. Further, although the reason is not clear, it is also preferable to mix a compound that causes the biodegradable material to strongly bind to the epoxidized cis-1,4-polyisoprene by mixing the compounds. Even when no covalent bond is formed, a mixture having higher compatibility and higher mechanical strength can be obtained by utilizing the compatibility between the biodegradable material and the epoxidized cis-1,4 polyisoprene.

In the present invention, a compound which functions so as to strengthen the bond between the biodegradable material and the epoxidized cis-1,4-polyisoprene by the mixing, regardless of the actual reaction caused by the mixing of the compounds. It is called a crosslinking agent and is preferably used.

The following can be mentioned as the above-mentioned crosslinking agent. Amine compounds: ethylenediamine, diethylenetriamine, triethylenepentamine, diethylaminopropylamine, hexamethylenediamine, polyaminoamide, mensendiamine, isophoronediamine,
Meta-xylenediamine, N-aminoethylpiperazine,
3,9 bis (3aminopropyl) -2,4,8,10-
Tetraoxaspiro (5,5) undecane, bis (4-
Amino-3-methylcyclohexyl) methane, bis (4
-Aminocyclohexyl) methane, diaminodiphenylmethane, diaminodiphenylsulfone, m-phenylenediamine, glutamic acid, aspartic acid, chitin chitosan and the like. Acid anhydride compounds: maleic anhydride, phthalic anhydride, succinic anhydride, trimellitic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, alkenyl succinic anhydride, hexahydrophthalic anhydride, methylhexa Hydrophthalic anhydride, adducts of linolenic acid and maleic anhydride, adducts of linoleic acid and maleic anhydride, adducts of eleostearic acid and maleic acid, polyazelaic anhydride, polydodecanoic anhydride, polyadipic anhydride, Polyazelaic anhydride, polysebacic anhydride, etc. Organometallic compounds: tetraisopropyl titanate, tetranor maltitanate,
Butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate, titanium acetyl acetate, titanium tetraacetyl acetate, polytitanium acetyl acetate, titanium octylene glycolate, titanium lactate, titanium triethanolamine, titanium ethyl acetoacetate, poly Hydroxytitanium stearate, aluminum acetyl acetate, aluminum organic acid chelate, sodium methoxide, sodium ethoxide and the like. Polymer crosslinking agent: carboxyl-modified low molecular weight polyisoprene, sulfonic acid-modified low molecular weight polyisoprene, hydroxyl group-modified low molecular weight polyisoprene, etc.

The amount of the cross-linking agent is appropriately selected depending on the type of the biodegradable material and the type of the cross-linking agent, but is usually 0.1 to 100 parts by weight of epoxidized cis-1,4-polyisoprene. 10 to 10 parts by weight, preferably 1 to 5 parts by weight can be used. Further, in addition to the crosslinking agent, water, peroxide, tertiary amine, phosphine, and the like can be added as an initiator, a reaction accelerator, or a curing accelerator.

The biodegradable material composition of the present invention is prepared by mixing various additives in addition to the biodegradable material, the epoxidized cis-1,4-polyisoprene as a modifier, and the crosslinking agent. Can be. Contains fillers such as silica, calcium carbonate, magnesium carbonate, kaolin, titanium oxide, carbon black, aluminum oxide, aluminum hydroxide, etc., lubricants such as higher aliphatic alcohols, aliphatic amides, metal soaps, fatty acid esters, etc. can do.

The mixing for obtaining the biodegradable material composition of the present invention is carried out by a conventionally known method, for example, after preliminarily mixing at a temperature near normal temperature with a mixer such as a Henschel mixer, a Bambury mixer, a kneader, It can be performed by kneading at a temperature of, for example, 80 to 160 ° C. using an extruder or the like. The biodegradable material composition of the present invention can be prepared by mixing a biodegradable material and an epoxidized cis-1,4-polyisoprene latex. Especially when the fibrous biodegradable material is, for example, cellulose or paper, a chip obtained by crushing or defibrating waste paper, for example, by a crusher or defibrator generally used for crushing or defibrating these. Alternatively, epoxidized cis-1,4-polyisoprene latex can be sprayed and sprayed on the fiber, and moisture can be evaporated and removed by residual crushing heat or defibration heat to mix. In this case, it is preferable that the various additives are previously mixed with the epoxidized cis-1,4-polyisoprene.

The biodegradable material composition of the present invention thus obtained comprises a biodegradable material and epoxidized cis-1,4-
It is produced by mixing polyisoprene, preferably further mixing a crosslinking agent, and further mixing various additives as desired. In addition, a composition in which a crosslinking agent is added to epoxidized cis-1,4-polyisoprene as a modifier is prepared in advance, and this composition is mixed with a biodegradable material and, if desired, various additives to form a raw material. Degradable material compositions can also be obtained. In the obtained biodegradable material composition of the present invention, the biodegradable material and the epoxidized cis-1,4-polyisoprene used as raw materials are (a) the third component such as a direct or cross-linking agent residue. (B) mixed in a compatibilized state, (c) mixed in an unreacted state, or in three states. Two or more of them exist in a mixed state.

The biodegradable material composition of the present invention is used to mold general thermoplastic resins such as a press, an extruder, an injection molding machine, a blow molding machine, a calender roll molding machine, a T-die molding machine and an inflation molding machine. In particular, a mixture of a thermoplastic biodegradable material and cis-1,4-isoprene can be produced using a T-die, an inflation molding machine, an extrusion molding machine, or an injection molding machine. A film, a sheet, a plate, a container, etc. utilizing biodegradability can be formed using a press or a press forming machine.

Further, among the biodegradable material compositions of the present invention,
The biodegradable material composition of cellulose and epoxidized cis-1,4-polyisoprene can be formed into a film, a plate, a container, and a honeycomb by using an extruder, a T-die molding machine, a dry fiber molding machine, a press machine, or the like. It can be a structure or the like. In this case, it is desirable to crosslink to further increase the strength, and the crosslinking method is desirably a method using heat, and a method using dielectric heating can be used in addition to a method using ordinary heat crosslinking. In addition, an inorganic filler or moisture can be added to increase the dielectric constant and mechanical strength. In addition, a foamed material whose foaming ratio is controlled by the amount of water added, the amount of dielectric heating energy, and the mold capacity can be obtained.

Further, from the biodegradable material composition of the present invention,
Biodegradable and cushioning material for packaging with high buffering effect, has a moisture control function, breathes, and is non-formalin building material or wallpaper, compost bag, heat insulating material, tatami floor, concrete formwork, furniture insulation board, It can produce wood substitutes such as flooring materials, bacterial carriers for wastewater treatment, and highly absorbent resins.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. The measurement of each physical property is performed by the following methods. (A) Yield strength, breaking strength, yield elongation, and breaking elongation: For a 1 mm-thick press-formed flat plate, JIS-
Measured at room temperature according to K7113. (B) Bending strength and bending modulus: 3 mm by press molding
The thickness of the flat plate was measured at room temperature according to JIS-K7203. (C) Izod impact strength: A 6 mm-thick press-formed flat plate was measured at room temperature according to JIS-K7110. The epoxidized cis-1,4-polyisoprene used was EPOXYPRENE 50 (trade name) manufactured by Kumpulan Guthrie Berhad unless otherwise specified.

Example 1 Polylactic acid as a biodegradable material used in this example is Lacty 9000 (trade name) manufactured by Shimadzu Corporation. After drying the polylactic acid at 80 ° C. for 4 hours, it was melted at 150 ° C. for 3 minutes using a mixing roll heated to a predetermined temperature, and the epoxidized cis-1,4-polyisoprene was added thereto. The mixture was kneaded for 20 minutes to prepare a biodegradable material composition in the form of a sheet. The obtained sheet is heated at 170 ° C.
Press molding for 4 minutes, for tensile test (1mm thickness),
For bending test (3mm thickness) and for Izod test (6
mm thick). The physical properties of these flat plates were measured. In addition, polylactic acid and epoxidation cis-1,
The mixing ratio of 4-polyisoprene was the weight ratio shown in Table 1, two types of compositions ((1) and (2)) were prepared, and the physical properties were measured for each. The results are shown in Table 1.

Comparative Example 1 In Example 1, the unmodified cis-1,4-polyisoprene was used in place of the epoxidized cis-1,4-polyisoprene. A biodegradable material composition was prepared in the form of a sheet in the same manner as in Example 1 except that the test was performed, a test plate was prepared, and the physical properties were measured. In addition, in this comparative example, as shown in Table 1, three types of compositions ((1) to (3)) were prepared. Table 1 shows the results
It was shown to.

[0030]

[Table 1]

Example 2 In this example, as an aliphatic polyester as a biodegradable material, Bionole 1020 (trade name) manufactured by Showa Polymer Co., Ltd.
Was used. After drying the aliphatic polyester at 80 ° C. for 4 hours, the mixture is melted at 130 ° C. for 3 minutes using a mixing roll heated to a predetermined temperature, and the epoxidized cis-1,4-polyisoprene has a weight ratio shown in Table 2. And then kneaded at 110 ° C. for 20 minutes to prepare two types of biodegradable material compositions ((1) and (2)) in sheet form.
Press molding at 150 ° C for 4 minutes from three types of sheets,
A test plate was prepared and physical properties were measured. The results are shown in Table 2.

Comparative Example 2 In Example 2, the epoxidized cis-1,4-polyisoprene was not used, or, instead, unmodified cis-1,4-polyisoprene was used. A biodegradable material composition was prepared in the form of a sheet in the same manner as in Example 1 except that the weight ratio was adjusted to a predetermined value. In addition, in this comparative example, as shown in Table 2, three types of compositions ((1) to (3)) were prepared. The results are shown in Table 2.

[0033]

[Table 2]

Example 3 In this example, Avicel TG101 (trade name) manufactured by Asahi Kasei Corporation was used as the cellulose powder as a biodegradable material. The above cellulose powder and titanium acetylacetonate (Orgatics TC-100 (trade name) manufactured by Matsumoto Pharmaceutical Co., Ltd.) as a crosslinking agent were diluted with 100 parts by weight of isopropanol to form a slurry. 70 ℃
, And vacuum dried at 60 ° C for 24 hours. Epoxidized-cis-1,4-polyisoprene and stearic acid are kneaded with a mixing roll, and the above-mentioned surface-treated cellulose powder and the cellulose powder not subjected to surface treatment are further kneaded.
Press molding at 100Kg for 30 minutes, 1m for tensile test
An m-thick sheet was prepared, and the yield point strength and the yield point elongation were measured. The results are shown in Table 3. In this embodiment,
Two types ((1) and (2)) of a composition using a crosslinking agent and a composition not using a crosslinking agent were prepared.
Is shown in

Comparative Example 3 In the preparation of the composition using the crosslinking agent of Example 3, unmodified cis-1,4-polyisoprene was used in place of the epoxidized cis-1,4-polyisoprene. Other than the above, a composition was prepared in the same manner, and a 1 m
An m-thick sheet was prepared, and the yield point strength and the yield point elongation were measured. The results are shown in Table 3.

[0036]

[Table 3]

Example 4 In this example, used newspaper crushed fiber was used as a biodegradable material. Used newspaper was previously broken by a commercially available shredder, and the cut paper was further defibrated by a defibrating machine (Turbo Kogyo Co., Ltd., Turbo Cutter C-350) to obtain a defibrated recycled fiber. Epoxidized cis-1,
35 parts by weight of 4-polyisoprene and 1 part by weight of stearic acid are kneaded with a mixing roll, and the above-mentioned used newspaper fiber is added to each of the amounts shown in Table 4, and water is added to the used newspaper paper in the amount shown in Table 4. It was kneaded. This is press-formed at 160 ° C. under a pressure of 100 kg for 30 minutes.
A sheet for a tensile test was prepared, and the yield point strength and the yield point elongation were measured. In this example, six types of compositions ((1) to (6)) were prepared, and the physical properties of each composition were measured. The results are shown in Table 4.

Comparative Example 4 The procedure of Example 4 was repeated, except that the unmodified cis-1,4-polyisoprene was used instead of the epoxidized cis-1,4-polyisoprene. A product was prepared and physical properties were measured. Table 4 shows the measurement results and the weight ratio of each component.

[0039]

[Table 4]

The results shown in Tables 1 to 4 clearly show that the composition of the present invention mixed with the epoxidized cis-1,4-polyisoprene has improved properties such as strength and elongation. In addition, each of the compositions of Examples 1 to 4 could be easily formed into a sheet.

Example 5 <Production of epoxidized cis-1,4-polyisoprene latex> In a reaction vessel equipped with a stirrer, 200 ml of natural rubber latex (solid content: 50% by weight), 5 g of formic acid,
After charging 71 g of 5% hydrogen peroxide and 180 g of water, the mixture was stirred at 60 ° C. for 24 hours to carry out an epoxidation reaction. The epoxidation ratio of the obtained epoxidized cis-1,4-polyisoprene latex was 48 mol%. <Mixing of used newspaper fiber, water, and epoxidized cis-1,4-polyisoprene latex> 100 g of used newspaper fiber of Example 4 was soaked in a hot air oven at 70 ° C., and epoxidized cis-1,4-synthesized in the above manner. 100 cc of polyisoprene latex (solid content: 34%) was spray-sprayed therein, and the dropped fiber was 100 × 100 ×
Placed in a 25 mm unsealed polyethylene container. The entire container was placed in a microwave heating device (1.5 kW, manufactured by Micro Electronics Co., Ltd.) and heated internally for 2 minutes. This was taken out of the polyethylene container, and its weight was measured. The result was 38 g and the density was 0.152 g / cm ³ . Further, a static compression test was performed, and a compression stress and a compression deformation rate were measured according to JIS Z 0234. The result is shown in FIG. Comparative Example 5 The procedure of Example 5 was repeated, except that the unmodified cis-1,4-polyisoprene was used instead of the epoxidized cis-1,4-polyisoprene.
g, a composition having a density of 0.144 g / cm ³ was obtained, and the physical properties were measured. The result is shown in FIG.

From the results shown in FIG. 1, the composition in which the epoxidized cis-1,4-polyisoprene as the modifier of the present invention is mixed has little deformation under compressive stress, and the improvement is clearly recognized.

Example 6 Composition (3) of Example 1, composition (3) of Example 2, composition (1) of Example 3, composition (5) of Example 4, and cellulose powder 50 g was frozen with liquid nitrogen, ground with a coffee mill, freeze-dried with liquid nitrogen, and ground with a vibration mill to prepare a powdery sample. These samples were added to an aged compost of city garbage, and air and water were supplied to a container at 58 ° C., and carbon dioxide generated after 45 days, 3 months, and 6 months was measured. In parallel with this, the carbon dioxide gas generated by the aged compost alone was measured. The amount of carbon dioxide generated from the aged compost alone was subtracted from the amount of carbon dioxide generated from each sample to obtain the amount of carbon dioxide generated due to the biodegradation of the sample alone. The number of carbons contained in each sample was measured by elemental analysis. From these results, 45 days, 60 days,
The biodegradation rate of each sample at 90 days was determined. Table 5 shows the results.

[0044]

[Table 5]

From the results in Table 5, it is clear that the biodegradable material composition of the present invention exhibits excellent biodegradability.

[0046]

According to the present invention, there is provided a modifier capable of improving the moldability of a low-cost epoxidized cis-1,4-polyisoprene biodegradable material. By mixing this modifier, a biodegradable material composition having improved moldability is provided. Moreover, this biodegradable material composition has improved elongation and brittleness of the biodegradable material. In addition, from the above biodegradable material composition having improved moldability and physical properties, a cushioning material for packaging, a wallpaper, a compost bag, a heat insulating material, a tatami floor, a concrete formwork, an insulation board for furniture, a floor material, a wastewater treatment. And a superabsorbent resin.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the compressive stress and the compressive deformation rate of the composition prepared in Example 5.

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Claims (4)

[Claims] 1. A biodegradable material modifier comprising an epoxidized polyisoprene. 2. A biodegradable material composition obtained by mixing a biodegradable material and an epoxidized polyisoprene. 3. A biodegradable material composition obtained by mixing a biodegradable material, an epoxidized polyisoprene, and a crosslinking agent. 4. An epoxidized cis-polyisoprene composition comprising a crosslinking agent.