JP2008024851A - Biodegradable composition, and molded article and use of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new biodegradable composition excellent in hydrolyzable property, and a molded article and use of the same. <P>SOLUTION: This biodegradable composition is characterized by containing (A) a block or graft copolymer having a constituting unit derived from a polyamino acid as (a-1) a hydrophilic segment, and a constituting unit derived from a degradable polymer as (a-2) a hydrophobic segment, and it is preferable to use the biodegradable composition further containing (B) a degradable resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a biodegradable resin composition, a molded body using the composition, and an application.

  Polyhydroxycarboxylic acids represented by polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), etc. are used as biodegradable plastics that are decomposed by moisture, enzymes, etc. in the natural environment or in vivo. Has been.

  For example, by using ring-opening copolymerization of glycolide (GLD), which is a cyclic dimer of glycolic acid, and lactide (LTD), which is a cyclic dimer of lactic acid, it is useful as a base material for sustained-release preparations. A method for obtaining a low molecular weight, polydisperse lactic acid-glycolic acid copolymer (PLGA) is known (for example, see Patent Document 1).

  In recent years, with the deterioration of the global environment, there has been an increasing interest in recycling resins and additives that are safe for living organisms and have little impact on the global environment. In addition, with the diversification of consumer needs, the need for biodegradable plastics such as polyhydroxycarboxylic acid has been advanced. For example, a phthalate ester plasticizer, which is one of resin plasticizers, is regarded as a safety problem as an endocrine disrupting substance (environmental hormone). In view of this, research has been conducted on proposals for restricting the use of phthalate ester plasticizers and resin additives to replace safer resin additives.

  Further, for example, PLA is used for applications such as disposable containers and packaging materials because it has good workability and excellent mechanical strength of molded products. However, since the degradation rate under conditions other than compost (for example, in seawater, soil, etc.) is relatively slow, there is a drawback that it is difficult to use for applications where it is desired to decompose and disappear within a few months.

  Therefore, in order to improve the hydrolysis rate of PLA, for example, a method of mixing a hydrophilic additive such as polyethylene glycol is also conceivable. However, since PLA has low hydrophilicity, it is hardly compatible with hydrophilic substances such as polyethylene glycol. Therefore, the additive is not practical because it is raised (bleeded out) at the time of molding or after molding, the mechanical strength of the molded product is lowered, or the appearance such as transparency is impaired.

  As far as the present inventors know, for example, an additive is added to an aliphatic polyester such as PLA, and the degradability is effectively prevented without significantly deteriorating the properties (mechanical strength, appearance, etc.) of the aliphatic polyester. No way has yet been found to promote it.

In addition, it is known that aliphatic polyesters such as PLA, in particular in the case of high molecular weight polymers, cause a significant decrease in molecular weight due to heating during molding. However, an effective method for suppressing thermal degradation of aliphatic polyester is not yet known.
JP 62-64824 A

  The objective of this invention is providing the novel biodegradable composition excellent in a hydrolyzability, the molded object using this composition, and a use.

  As a result of intensive studies to achieve the above object, the present inventors have found that a biodegradable composition containing a copolymer having a hydrophilic segment and a hydrophobic segment and a molded article using the composition are short-term. In the meantime, it was not only decomposed in the environment, but also found to be excellent in mechanical strength, flexibility, waterproofness and touch.

That is, the present invention provides the following [1] to [27].
[1]
A block or graft copolymer (A) having a structural unit derived from a polyamino acid as a hydrophilic segment (a-1) and a structural unit derived from a degradable polymer as a hydrophobic segment (a-2) A biodegradable composition comprising

[2]
The biodegradable composition according to [1], further comprising a degradable resin (B).
[3]
A biodegradable molded article using the biodegradable composition according to [1] or [2].

[4]
A hot melt adhesive using the biodegradable composition according to [1] or [2].
[5]
An aqueous paper coating composition using the biodegradable composition according to [1] or [2].

[6]
An easily peelable pressure-sensitive adhesive material using the biodegradable composition according to [1] or [2].
[7]
A thermal transfer medium using the biodegradable composition according to [1] or [2].

[8]
[3] A biodegradable molded article, wherein the biodegradable molded article is a fiber.
[9]
[3] A biodegradable molded article, wherein the biodegradable molded article is a non-woven fabric.

[10]
The biodegradable molded article according to [3], wherein the biodegradable molded article is a film.
[11]
[3] The biodegradable molded product according to the above, wherein the biodegradable molded product is a sanitary packaging material.

[12]
[3] A biodegradable molded product according to the above, wherein the biodegradable molded product is a food packaging material.
[13]
[3] A biodegradable molded product according to claim 3, wherein the biodegradable molded product is a protective film.

[14]
[3] The biodegradable molded product according to [3], wherein the biodegradable molded product is a porous film.
[15]
[3] A biodegradable molded article according to claim 3, wherein the biodegradable molded article is an agricultural and horticultural material.

[16]
[3] The biodegradable molded article according to the above, wherein the biodegradable molded article is a pet waste disposal agent.

[17]
[3] A biodegradable molded article, wherein the biodegradable molded article is a sustained-release drug.
[18]
[3] The biodegradable molded product according to [3], which is a casing of an electronic device.

[19]
[3] A biodegradable molded product according to the above, wherein the biodegradable molded product is a processing aid.
[20]
[3] A biodegradable molded product according to claim 3, wherein the biodegradable molded product is a civil engineering and building material.

[21]
[3] A biodegradable molded product according to claim 3, wherein the biodegradable molded product is a cleaning article.
[22]
[3] The biodegradable molded article according to the above, wherein the biodegradable molded article is a wet sheet.

[23]
[3] A biodegradable molded article according to the above-mentioned item, wherein the biodegradable molded article is a leisure article.
[24]
[3] A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a toy.

[25]
[3] A biodegradable molded article, wherein the biodegradable molded article is a teaching material.
[26]
[3] The biodegradable molded article according to the above, wherein the biodegradable molded article is an acid absorbent.

[27]
[3] The biodegradable molded product according to the above, wherein the biodegradable molded product is an alkali absorbent.

According to the present invention, a biodegradable composition with improved degradability can be obtained.
The biodegradable composition provided by the present invention and a molded body using the composition have excellent degradability, and are excellent in mechanical strength, flexibility, waterproofness, and touch. Can be used.

Next, the present invention will be specifically described.
[Biodegradable composition]
The biodegradable composition of the present invention has a structural unit derived from a polyamino acid as a hydrophilic segment (a-1) and a structural unit derived from a degradable polymer as a hydrophobic segment (a-2) Or it is a resin composition containing a graft copolymer (A), and it is preferable that the decomposable resin (B) is further included.

  In the present invention, the “hydrophobic segment” is a segment derived from a degradable polymer that is hardly soluble or insoluble in water, and is more hydrophobic than the other hydrophilic segment. The “hydrophilic segment” is a segment derived from a polymer that is soluble in water or hardly soluble but more hydrophilic than the hydrophobic segment.

In the copolymer (A) of the present invention, the hydrophilic segment (a-1) is not particularly limited as long as it contains a structural unit derived from a polyamino acid in the segment. The hydrophobic segment (a-2) is not particularly limited as long as it contains a structural unit derived from a degradable polymer in the segment.

The preferred form of the hydrophilic segment (a-1) of the copolymer (A) is a structural unit derived from aspartic acid, and the preferred form of the hydrophobic segment (a-2) is the following dibasic It consists of structural units derived from acids and dihydric alcohols, hydroxycarboxylic acids, lactides, lactones, or carbonates.

Hereinafter, a specific example will be described.
1. Dibasic acids and dihydric alcohols Specific examples of the aliphatic dihydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-butanediol, 1, Examples include 4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, polytetramethylene glycol, and 1,4-cyclohexanediol.

  Specific examples of the aliphatic dibasic acid include succinic acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid and the like.

2. Hydroxycarboxylic acids For example, α-hydroxymonocarboxylic acids (eg, glycolic acid, lactic acid, 2-hydroxybutyric acid, 2-hydroxyvaleric acid, 2-hydroxycaproic acid, 2-hydroxycapric acid)
, Hydroxydicarboxylic acids (for example, malic acid), hydroxytricarboxylic acids (for example, citric acid), and the like.

3. Lactides, such as glycolide, lactide, p-dioxanone, 1,4-benzylmalolactonate, malite benzyl ester, 3-[(benzyloxycarbonyl) methyl] -1,4-dioxane-2,5-dione, tetra And methyl glycolide.

4). Lactones For example, β-propiolactone, β-butyrolactone, α, α-bischloromethylpropolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, 3-n-propyl-δ-valerolactone, 6,6-dimethyl-δ-valerolactone, 3,3,6-trimethyl-1,4-dioxane-dione, 3,3,6-trimethyl-1,4-dioxane-dione, ε-caprolactone, dioxepanone, 4 -Methyl-7-isopropyl-ε-caprolactone, N-benzyloxycarbonyl-L-serine-β-lactone and the like.

5. Carbonates For example, ethylene carbonate, tetramethylene carbonate trimethylene carbonate, neopentylene carbonate, ethylene oxolate, propylene oxolate and the like.

A preferred form of the hydrophobic segment (a-2) of the copolymer (A) is a structural unit derived from hydroxycarboxylic acids, lactides or lactones. Specific examples include the above-mentioned compounds, and in particular, α-hydroxycarboxylic acid, glycolide, lactide, p-dioxanone, β-propiolactone, β-butyrolactone, δ-valerolactone, and ε-caprolactone. It is preferably a derived structural unit. Among these, a structural unit derived from glycolic acid, lactic acid, glycolide, lactide, or ε-caprolactone is more preferable.

A preferred form of the copolymer (A) includes a structural unit derived from aspartic acid as the hydrophilic segment (a-1) and a dibasic acid and dihydric alcohol as the hydrophobic segment (a-2) in the structure. , A structural unit derived from hydroxycarboxylic acids, lactides, lactones or carbonates (hereinafter referred to as “structural unit derived from hydrophobic segment (a-2)”).
) And coexist. This copolymer contains 1 mol% or more of structural units derived from aspartic acid in the hydrophilic segment (a-1) and 1 mol% or more of structural units derived from the hydrophobic segment (a-2). It is preferable. The hydrophilic segment (a- in the copolymer (A)
The composition ratio of the aspartic acid-derived unit 1) and the hydrophobic segment (a-2) -derived unit 1) is not particularly limited, but is preferably 1/1 to 1/50. In the copolymer (A), components other than the aspartic acid of the hydrophilic segment (a-1) and the hydrophobic segment (a-2) may be present by copolymerization. However, the amount needs to be a level that does not significantly impair the properties of the copolymer (A). Considering this point, the amount is about 20 mol% or less. Aspartic acid is dehydrated and condensed to produce a polymer having a succinimide unit, and the constituent unit derived from aspartic acid is meant to include a succinimide unit. The aspartic acid unit contained in the structure of the copolymer (A) can be a mixture of an α-amide type monomer unit and a β-amide type monomer unit, and the ratio of both is not particularly limited. .

  The copolymer (A) is usually obtained by a copolymerization reaction of aspartic acid and hydroxycarboxylic acids, lactides or lactones, and the production method is not particularly limited. Generally, it can be obtained by mixing aspartic acid and hydroxycarboxylic acids in a desired ratio and polymerizing under heating.

In order to constitute a structural unit derived from the hydrophobic segment (a-2) in the copolymer (A), α-hydroxycarboxylic acid, glycolide, lactide, p-dioxanone, 2-hydroxybutyric acid, 2- At least one selected from the group consisting of hydroxyvaleric acid, 2-hydroxycaproic acid, β-propiolactone, β-butyrolactone, δ-valerolactone, and ε-caprolactone is used. More preferably, glycolic acid, lactic acid, glycolide, lactide, p-dioxanone, 2-hydroxybutyric acid, 2-hydroxyvaleric acid, 2-hydroxycaproic acid, β-propiolactone, β-butyrolactone, δ-valerolactone and ε -Use at least one selected from the group consisting of caprolactone. Particularly preferably, at least one selected from the group consisting of glycolic acid, lactic acid, glycolide, lactide and ε-caprolactone is used. Most preferably, lactic acid is used.

  About the molecular weight of a copolymer (A), it is preferable that a weight average molecular weight is about 1000 or more and 100,000 or less from the point which can mix favorably with degradable resin (B) and to enlarge a decomposition promotion effect. More preferably, it is 2,000 or more and 50,000 or less, and further preferably 3,000 or more and 20,000 or less.

The decomposable resin (B) used in the present invention is not particularly limited as long as it is a resin having decomposability, but more specifically, the following resins are listed as representatives.
1. Aliphatic polyesters (1) Dibasic acid-dihydric alcohol copolymers Specific examples of the aliphatic dihydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, and polypropylene glycol. 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, polytetramethylene glycol, 1 , 4-cyclohexanediol and the like.

  Specific examples of the aliphatic dibasic acid include succinic acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid and the like.

  Examples thereof include homopolymers or copolymers synthesized from any one or more of the above dibasic acids and dihydric alcohols, copolymers with other arbitrary monomers, or mixtures thereof.

(2) Polyhydroxycarboxylic acids α-hydroxymonocarboxylic acids (eg glycolic acid, lactic acid, 2-hydroxybutyric acid, 2-hydroxyvaleric acid, 2-hydroxycaproic acid, 2-hydroxycapric acid), hydroxydicarboxylic acids (eg , Malic acid), homopolymers or copolymers synthesized from one or more hydroxycarboxylic acids such as hydroxytricarboxylic acids (e.g. citric acid), copolymers with any other monomers, or mixtures thereof.

(3) Polylactides Glycolide, lactide, benzyl malolactonate, malite benzyl ester, 3-
Homopolymers or copolymers synthesized from one or more lactides such as [(benzyloxycarbonyl) methyl] -1,4-dioxane-2,5-dione, copolymers with any other monomer, or mixtures thereof Etc.

(4) Polylactones Homopolymers or copolymers synthesized from one or more lactones such as β-propiolactone, δ-valerolactone, ε-caprolactone, N-benzyloxycarbonyl-L-serine-β-lactone, Examples thereof include copolymers with other arbitrary monomers, and mixtures thereof. In particular, these are glycolides, which are cyclic dimers of α-hydroxy acids,
It can be copolymerized with lactide and the like.

2. Polyanhydrides Examples include poly [1,3-bis (p-carboxyphenoxy) methane] and poly (terephthalic acid-sebacic anhydride).

3. Degradable polycarbonates Examples include poly (oxycarbonyloxyethylene) and spiro orthopolycarbonate.

4). Polyorthoesters Examples include poly {3,9-bis (ethylidene-2,4,8,10-tetraoxaspiro [5,5] undecane-1,6-hexanediol)}.

5. Poly-α-cyanoacrylates Examples include polybutyl α-cyanoacrylate.
6). Polyphosphazenes Examples include polydiaminophosphazenes.

7). Other degradable resins Microbial production synthetic resins typified by polyhydroxyesters, etc., resins that have been given degradability by blending starch, modified starch, skin powder, refined cellulose, etc. with the various resins mentioned above It is done.

  Of the various resins listed above, the aliphatic polyesters are preferred from the viewpoint that the copolymer (A) and the decomposable resin (B) are not separated and mixed more uniformly, and particularly dibasic acid-divalent. Alcohol copolymers, polyhydroxycarboxylic acids, polylactides, and polylactones are preferred.

  In the present invention, polyhydroxycarboxylic acid means a polymer or copolymer of hydroxycarboxylic acid having both a hydroxyl group and a carboxyl group. As the hydroxycarboxylic acid, for example, lactic acid, glycolic acid, hydroxycaproic acid, hydroxybutanoic acid, hydroxypropionic acid and the like are preferable. In polyhydroxycarboxylic acid, components (copolymerization units) other than hydroxycarboxylic acid may be present. However, the proportion of the constituent units derived from at least hydroxycarboxylic acid in the polyhydroxycarboxylic acid is preferably 20 mol% or more, and more preferably 50 mol% or more.

The most preferably used polyhydroxycarboxylic acid is polylactic acid, lactic acid-glycolic acid copolymer, polycaprolactone.
In the present invention, the molecular weight of the degradable resin (B) is not particularly limited. However, considering the strength, the weight average molecular weight of the decomposable resin (B) is preferably from 1,000 to 1,000,000, more preferably from 3,000 to 500,000.

  The biodegradable composition of the present invention contains the above-mentioned copolymer (A) and preferably contains a decomposable resin (B). The composition also contains various additives depending on the purpose, such as plasticizers, fillers, antioxidants, ultraviolet absorbers, heat stabilizers, flame retardants, mold release agents, inorganic additives, crystal nucleating agents, electric resistance agents. An inhibitor, a pigment, and an antiblocking agent may be contained as an additional component.

  As the plasticizer, those having decomposability and excellent compatibility with the decomposable resin (B) are preferably used. Examples include monovalent or polyvalent fatty acid ester plasticizers, monovalent or polyvalent aliphatic alcohol ester plasticizers, polyalkylene glycol plasticizers, aliphatic polyester plasticizers, and the like. Specifically, phthalic acid derivatives such as di-n-octyl phthalate, di-2-ethylhexyl phthalate and dibenzyl phthalate, isophthalic acid derivatives such as diisooctyl phthalate, adipine such as di-n-butyl adipate and dioctyl adipate Acid derivatives, maleic acid derivatives such as di-n-butyl malate, citric acid derivatives such as tri-n-butyl citrate, itaconic acid derivatives such as monobutyl itaconate, oleic acid derivatives such as butyl oleate, glycerin monoricinoleate, etc. Phosphate plasticizers such as ricinoleic acid derivatives, tricresyl phosphate, trixylenyl phosphate, triethyl acetyl citrate, tributyl acetyl citrate, lactic acid, linear lactic acid oligomer, cyclic lactic acid oligomer or lactide It can be illustrated. In particular, at least one selected from citric acid ester, glycerin ester, phthalic acid ester, adipic acid ester, sebacic acid ester, azelaic acid ester and triethylene glycol ester having two or more carboxylic acid ester groups in the molecule An ester compound is preferred. These plasticizers may be used singly or in combination of two or more.

The biodegradable composition of the present invention preferably further contains a decomposable resin (B) in addition to the copolymer (A), and the decomposable resin (B) 0 with respect to 100 parts by weight of the copolymer (A). .03-1000
00 parts by weight is preferred.
For example, it can be obtained by mixing a copolymer (A) having a weight average molecular weight of 1000 or more and 100,000 or less into a degradable resin (B) having a weight average molecular weight of 3000 or more and 500,000 or less. When the composition ratio of the copolymer (A) is large, the composition has a high decomposition rate. When the composition ratio of the copolymer (A) is too small with respect to the resin (B), it may be difficult to expect the effect of promoting the decomposition rate.

  When a composition that does not significantly impair the properties of the degradable resin (B) is desired, preferably, the weight composition ratio of the copolymer (A) to the degradable resin (B) is 1/99 to 33 / Set to about 67. More preferably, it is 2 / 98-20 / 80, More preferably, it is 3 / 97-10 / 90.

  In the present invention, the method of mixing the decomposable resin (B) with the copolymer (A) is not particularly limited. Preferably, both are melted by heating or dissolved in a solvent and mixed with stirring. For example, copolymer (A), degradable resin (B), and other additives such as plasticizers, inorganic fillers, dispersants, and stabilizers, if necessary, using a Henschel mixer, super mixer, tumbler mixer, etc. Are mixed and then continuously kneaded using a single-screw or twin-screw extruder. Here, in order to further improve the dispersibility of the copolymer (A), the filler and the like into the degradable resin (B), a twin screw extruder is preferred.

  The biodegradable composition of the present invention may be used as a hot melt adhesive, an aqueous paper coating composition, an easily peelable adhesive, a thermal transfer medium, and a molded body. Even when the biodegradable composition of the present invention diffuses into the natural world, it is preferable because of the biodegradability of the composition because of its low environmental impact.

  The hot melt adhesive using the biodegradable composition of the present invention can be used in various applications such as sanitary materials, packaging, heat insulating materials, and woodworking. Moreover, since the product using the hot melt adhesive of the present invention has hydrolyzability and biodegradability, the adhesive part can be removed by washing with water after use as a product. Can dissociate.

  The aqueous paper coating composition using the biodegradable composition of the present invention can be applied to a substrate such as paper, metal, plastic, etc., thereby improving printability and protecting the base. Further, when the base of paper or the like coated with the aqueous paper coating composition of the present invention is collected and reused, the aqueous paper coating composition can be removed by washing with water or warm water. Therefore, it is possible to easily collect the base such as paper.

  The easily peelable adhesive material using the biodegradable composition of the present invention preferably contains a peelability adjusting agent as an additional component. As the peelability adjusting agent, components having an action as a slip agent, an antistatic agent and a water repellent agent can be used. The easily peelable pressure-sensitive adhesive material of the present invention can be used as a sanitary material protective sheet, and can be easily peeled off because it contains a peelability adjusting agent upon peeling. In addition, when a complicated shape is protected, the easily peelable adhesive material may remain on a member intended to protect hygiene materials or the like, but the easily peelable adhesive material of the present invention can be easily removed by washing. This is preferable because the protective surface is not damaged.

  The thermal transfer medium using the biodegradable composition of the present invention contains a dye and / or pigment as an additional component, and preferably further contains a plasticizer. Since the thermal transfer medium of the present invention has hydrolyzability, the transferred image can be easily deleted after being transferred to a film or the like.

[Biodegradable molded product]
The biodegradable molded article of the present invention comprises the aforementioned biodegradable composition.
The biodegradable molded product of the present invention may be a fiber. The biodegradable fiber of the present invention having both hydrolyzability and biodegradability may be used as a non-woven fabric or medical clothing obtained by further processing the fiber.

  As a method for obtaining the biodegradable fiber, a known spinning method may be applied, and single spinning or composite spinning may be used. Particularly, examples of the composite spinning include core-sheath type and parallel type composite spinning. As a specific spinning method, a melt spinning method in which the biodegradable composition is melt-spun using an extruder; the biodegradable composition is dissolved in a solvent to form a solution; Examples thereof include a wet spinning method in which the solution is discharged into a poor solvent; a dry spinning method in which the solution is discharged into a dry gas from a nozzle. In the melt spinning method, a known extruder such as a single screw extruder or a twin screw extruder can be used.

  The biodegradable molded product of the present invention may be a nonwoven fabric. There is no restriction | limiting in particular as a method of obtaining the nonwoven fabric of this invention, For example, it manufactures by a well-known method, for example, a dry method, a spun bond method, a melt blow method, a wet method. That is, it is obtained by spinning the composition containing the biodegradable polymer of the present invention or the biodegradable polymer and an additive, forming a web, and bonding the web by a conventionally known method.

  A known spinning method is applied to the spinning method of the raw fiber. Single spinning or composite spinning may be used. Particularly, the form of composite spinning includes core-sheath type or parallel type composite spinning. Examples of the spinning method include a melt spinning method in which melt spinning is performed using an extruder, and a wet spinning method in which the biodegradable composition is dissolved in a solvent to form a solution, and then the solution is discharged from a nozzle into a poor solvent. , Dry spinning or the like in which the solution is discharged from a nozzle into a dry gas is applied. In the melt spinning method, a known extruder such as a single screw extruder or a twin screw extruder can be used.

  The diameter of the die (nozzle) of the extruder is appropriately determined according to the relationship between the required fiber diameter (yarn diameter) and the discharge speed and take-off speed of the extruder, but preferably 0.1 to 3.0 mm. Degree. In any spinning method, it is not always necessary to stretch the fiber after spinning, but when stretching is performed, the fiber is stretched 1.1 to 10 times, preferably 2 to 8 times. A preferable yarn diameter of the fiber is 0.5 to 40 denier. Moreover, the single fiber or the composite fiber constituting the nonwoven fabric of the present invention may be either a long fiber or a short fiber, and can be appropriately selected depending on the purpose of use.

  From the obtained fiber, a fiber lump called a web is formed. A known method can be used as a method for producing the web, and is not particularly limited. For example, a card type using a flat card machine, a roller card machine, a garnet machine, etc., and a melt blow type can be mentioned. Further, when the resin is spun, a spunbond type in which high-speed air is blown when fibers come out from the nozzle of the spinning machine and collected on a perforated conveyor perpendicular to the airflow to form a web may be used.

A known method can be used to obtain the nonwoven fabric of the present invention from the web thus obtained. For example, a needle punch method for entanglement with a needle, a stitch bond method for entanglement with a yarn, a thermal bond method for adhesion by heat, a chemical bond method using an adhesive, and a resin bond method may be mentioned. Nonwoven basis weight of the present invention is preferably 1 to 50 g / m ^2, more preferably from 5 to 20 g / m ^2.
Further, the biodegradable molded product of the present invention may be a draining bag, medical clothing, experimental clothing, or sheet obtained by further processing the nonwoven fabric.

The biodegradable molded product of the present invention may be a film. There is no restriction | limiting in particular as a method of obtaining the film which consists of a biodegradable composition of this invention, It shape | molds in a film form or a sheet form with a well-known shaping | molding method. Examples of the method include forming a film or a sheet by a T-die molding method, an inflation molding method, a calendar molding method, a hot press molding method, or the like. Further, these films and sheets may be stretched in at least one direction. The stretching method is not particularly limited, and examples thereof include a roll stretching method, a tenter method, and an inflation method.

  The method for obtaining a film having a shape suitable for the application from the biodegradable composition of the present invention is not particularly limited and can be produced by a known method. For example, a method of performing extrusion molding or injection molding on a mold, etc. Is mentioned.

  The thickness of the film of the present invention is preferably thinly formed in order to enhance its hydrolyzability and biodegradability, but can be freely adjusted to satisfy the strength and flexibility. The preferred thickness of the film is 5 to 300 μm, and more preferably 10 to 100 μm. Further, the value of the tensile elastic modulus is not particularly limited, but is usually preferably 1200 MPa or less, and more preferably 600 MPa or less.

The biodegradable molded article of the present invention may be a packaging film, a packaging bag, a compost bag, a shopping bag, a garbage bag, a shrink film, or the like obtained by further processing the film.
It is particularly preferable to use as a garbage bag for garbage. The garbage bag of the present invention is preferable because it hardly hydrolyzes with the water content that throws away the garbage into the garbage bag, and it is possible to recycle the garbage together with the garbage by collecting it after hydrolysis.

  Currently, from the viewpoint of environmental protection, the recycling of raw garbage (for example, biogas, recycling as liquid fertilizer) is being considered, but usually each household collects raw garbage in a separate container from other garbage, It is transferred to a large container installed at a collection location used by several to several tens of households for collection and resource recovery. However, when moving to a large container, the odor of raw garbage becomes a problem. ing. When a garbage bag made using the film of the present invention is used, it has hydrolyzability and biodegradability, so that it is possible to simultaneously collect and recycle the garbage bag. For this reason, since it can collect | recover without feeling odor etc., the improvement of a collection rate is anticipated.

  The packaging film is preferably used for sanitary goods and other sanitary goods. When the packaging film of the present invention is used as a packaging material for sanitary goods, it is preferable that the sanitary goods can be taken out as they are after being taken out.

  A packaging film may be used as a packaging material for food. When it is used as a food packaging film, it is adjusted so that hydrolysis and biodegradation occur by the action of a large amount of water and microorganisms at the stage of disposal without hydrolysis or biodegradation during the period of preservation of food. Can be used.

  The biodegradable molded article of the present invention may be a protective film. The protective film of the present invention is attached to or attached to the shield part of a helmet or the lens part of sports goggles used for skiing, etc., and is peeled off when water, mud, oil, etc. adheres and obstructs the field of view. It is used for the purpose of securing the field of view. Since the protective film of the present invention has hydrolyzability and biodegradability, it is preferable because it is hydrolyzed in soil and water even if it is scattered in the natural environment.

The biodegradable molded article of the present invention may be a porous film having air permeability. A porous film can be obtained by forming the biodegradable composition described above into a film using an extrusion method or the like, preferably using a T-die method, and then stretching. In order to obtain a porous film, a filler (inorganic filler and / or organic filler) is usually contained as an additional component. Inorganic fillers include calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, aluminum hydroxide, zinc oxide, magnesium hydroxide, calcium oxide, magnesium oxide , Titanium oxide, alumina, mica, zeolite, silicate clay and the like. Among these, calcium carbonate, magnesium oxide, barium sulfate, talc, clay, silica, diatomaceous earth, titanium, and zeolite are preferable. Examples of the organic filler include cellulose powder such as wood powder and pulp powder. These fillers may be used alone or in combination of two or more.

  The average particle size of the filler is preferably 30 μm or less, more preferably 10 μm or less, and particularly preferably in the range of 0.7 to 5 μm. If the particle size is too large, the fineness of the pores of the film will deteriorate, and if it is too small, the dispersibility in the resin will deteriorate. In addition, after making a planar unstretched sheet, the film becomes porous and becomes air permeable by uniaxially stretching in the longitudinal direction or biaxially stretching in the longitudinal and lateral directions.

  The biodegradable molded product of the present invention may be an agricultural or horticultural material. Examples of agricultural and horticultural materials include multi-films, seedling pots, agricultural and horticultural tapes, fruit cultivation bags, piles, fumigation sheets, and greenhouse films. For example, when used as a seedling pot, it has sufficient strength at the stage of growing seedlings and distribution stage by adjusting its hydrolyzability and biodegradability, and it can be decomposed after being embedded in soil. It is possible to eliminate the trouble of removing the seedling pot after raising the seedling and before burying the soil.

  The biodegradable molded product of the present invention may be a pet waste disposal material. Examples of the pet filth treatment agent include non-woven fabrics, films and sheets used in pet filth collection bags and pet sheets. For example, when used as a pet waste collection bag, it does not hydrolyze with the amount of water that the waste has, but after being put into the toilet after putting the pet waste in the hydrolyzable and biodegradable nature of the pet waste collection bag This is preferable.

  The biodegradable molded article of the present invention may be a sustained-release drug, specifically, a sustained-release drug, agricultural chemical, veterinary drug, or fertilizer. When the biodegradable molded product of the present invention is used as a sustained-release drug in medicines or veterinary drugs, it is generally gradually degraded by water in the body, and accordingly, a stable amount of a medicinal component is released for a long time. be able to. In addition, when the biodegradable molded article of the present invention is used for agricultural chemicals, fertilizers, etc., it is possible to release the drug at an arbitrary time by decomposing the water-disintegrating molded article at an arbitrary time with moisture in the ground. Is possible.

  The biodegradable molded article of the present invention may be a casing of an electric device. Specifically, it can be used as a housing of a personal computer or a home appliance. Since normal electric equipment is not used outdoors, there is no risk of hydrolysis by a large amount of water, and therefore it can be used as a casing. Further, after use, it is hydrolyzed and biodegradable, so that it can be easily treated and can be easily separated from other materials (metal, semiconductor, etc.).

  The biodegradable molded product of the present invention may be a processing aid, specifically a core during resin molding. When the biodegradable molded article of the present invention is used as a core at the time of resin molding, the biodegradable molded article has hydrolyzability, so that the core can be easily washed by washing with water after molding. Since it can be removed, resin molded bodies having various shapes can be easily produced.

  The biodegradable molded article of the present invention may be a civil engineering and building material. As a civil engineering construction material, it can be suitably used as a vegetation net, a vegetation bag, a vegetation pot, a three-dimensional net, a civil engineering fiber, a pile, and a heat insulating material.

When the biodegradable molded article of the present invention is used as a vegetation net, it can be used as a vegetation net by forming the biodegradable composition into a fiber and braiding it. The vegetation net may be used as a vegetation bag by knitting it into a bag shape. By using the vegetation net and / or vegetation bag of the present invention, the slope is protected by the vegetation net and / or the vegetation bag until the plant is sufficiently rooted during the protection of the slope and the greening work, and thereafter the vegetation is protected. Nets and / or vegetation bags hydrolyze and biodegrade.

  When the biodegradable molded article of the present invention is used as a vegetation pot, it can be used as a normal flower pot while the seedling grows, and in transplanting, utilizing hydrolysis and biodegradability. The vegetation pot can be buried in the soil. As a result, it is useful from the viewpoint of environmental conservation because it saves the trouble of collecting the vegetation pot and does not incinerate. In addition, the transplant yield rate can be improved without damaging the roots of seedlings and the like during transplantation. In this case, it is especially effective for reforestation of bushes and cedars in the mountains, and transplanting of seedlings that tend to damage the roots, and after the vegetation pot is buried in the soil, it biodegrades as soon as possible. Does not hinder root growth such as seedlings.

  The biodegradable molded article of the present invention may be a cleaning article. As a cleaning article, it can be suitably used as a wet wiper or a brush. Since the cleaning article of the present invention has hydrolysis and biodegradability, it is preferable because it is hydrolyzed in soil and water even if it is scattered in the natural environment.

  The biodegradable molded product of the present invention may be a wet sheet. Specifically, it can be used as a wet sheet (also referred to as wet wipes) for wiping off dirt used for wiping the human body and wiping equipment such as toilets. Since the biodegradable molded article of the present invention can be a wet sheet containing various chemicals and is hydrolyzable with a large amount of water, it can be poured into a toilet after use. It can be suitably used as a wet sheet for wiping off.

  The biodegradable molded article of the present invention may be leisure goods, toys or educational materials. Specifically, it can be used as a leisure sheet, leisure carpet, leisure tableware, fishing tackle, and work material. For example, when the biodegradable molded article of the present invention is a leisure sheet, a leisure carpet or a tableware for leisure, discarding it once is not preferable from the viewpoint of environmental protection. Used above. Leisure goods may spread into the environment against the user's will due to, for example, a gust of wind during use, but because it has biodegradability, there is little impact on the environment even if it diffuses into the environment Therefore, it is preferable. In addition, when used as fishing gear, it can be suitably used by weakening hydrolyzability, and even if it is diffused into the environment, it has biodegradability and hydrolyzability. Therefore, it is preferable because the load on the environment is small.

  The biodegradable molded article of the present invention may be an acid absorbent. The acid absorbent is obtained by molding a biodegradable composition in which a salt showing alkalinity in water is mixed. By loading the acid absorbent into a drain pipe or the like, the acid can be absorbed and neutralized, so that it can be used for wastewater treatment. The biodegradable molded article of the present invention is preferable because it has a biodegradability even when it is diffused to the natural world and has a low environmental impact. As the salt exhibiting alkalinity in water, calcium carbonate, sodium carbonate, calcium acetate, sodium acetate and the like are preferable. These salts may be used alone or in combination of two or more. When the total biodegradable composition is 100 parts by weight, the ratio of the salt to be mixed is preferably 0.1 to 30 parts by weight, and more preferably 0.5 to 20 parts by weight. As a method for obtaining a biodegradable composition in which a salt exhibiting alkalinity in water is mixed, a known method such as a melt-kneading method can be used.

The biodegradable molded article of the present invention may be an alkali absorbent. The alkaline absorbent is obtained by molding a biodegradable composition in which a salt that exhibits acidity in water is mixed. By loading the alkali absorbent into a drain pipe or the like, the alkali can be absorbed and neutralized, so that it can be used for wastewater treatment. The biodegradable molded article of the present invention is preferable because it has a biodegradability even when it is diffused to the natural world and has a low environmental impact. As the salt showing acidity in water, ammonium chloride, ammonium sulfate and the like are preferable. These salts may be used alone or in combination of two or more. When the total biodegradable composition is 100 parts by weight, the ratio of the salt to be mixed is preferably 0.1 to 30 parts by weight, and more preferably 0.5 to 20 parts by weight. As a method for obtaining a biodegradable composition in which a salt that exhibits acidity in water is mixed, a known method such as a melt-kneading method can be used.

[Example]
Hereinafter, the present invention will be described in more detail with reference to examples. The evaluation method used in this example is as follows.

[1] Polymer weight average molecular weight (Mw)
The weight average molecular weight (hereinafter referred to as “Mw”) of the polymer was determined by gel permeation chromatography (hereinafter referred to as “GPC”). Polystyrene was used as a standard substance.

[2] Tensile strength and tensile modulus of the film Tensile strength at break and tensile modulus were measured by pulling a film test piece punched into a dumbbell mold at a tensile rate of 50 mm / min and measuring the stress. Asked.

[Preparation Example 1]
A glass reactor equipped with a stirrer and a deaeration port was charged with 13.3 g (0.1 mol) of L-aspartic acid and 50 g of 90% L-lactic acid aqueous solution (0.5 mol of lactic acid) under a nitrogen stream. , 18
The reaction was performed at 0 ° C. for 25 hours. The product was taken out and cooled and solidified, and the resulting solid was pulverized to obtain a powdery polymer. Mw by chloroform GPC was 9000.

[Preparation Example 2]
The reaction was carried out for 10 hours in the same manner as in Preparation Example 1 except that 20 g (0.2 mol) of 90% L-lactic acid aqueous solution was used. Mw by DMF GPC was 9000.

[Preparation Example 3]
The reaction was carried out for 12 hours in the same manner as in Preparation Example 1, except that 10 g (0.1 mol) of 90% L-lactic acid aqueous solution was used. Mw by DMF GPC was 11000.

[Preparation Example 4]
A glass reactor equipped with a stirrer and a deaeration port was charged with 13.3 g (0.1 mol) of L-aspartic acid and 36.0 g (0.25 mol) of L-lactide. The reaction system was heated to 180 ° C., and after 1 and a half hours from the start of heating, the pressure of the reaction system was gradually reduced to 1 mmHg after 2 hours. After further heating for 2 hours, the reaction was conducted at 160 ° C. for 15 hours. The product was taken out and cooled and solidified, and the resulting solid was pulverized to obtain a powdery polymer. Mw by chloroform GPC was 8600.

[Preparation Example 5]
In a glass reactor equipped with a stirrer and a deaeration port, 31.9 g of L-aspartic acid (0.24
Mol), 70.9 g (0.6 mol) of succinic acid, 54.1 g of 1,4-butanediol (0.
6 mol) and 24 g (0.24 mol) of 90% L-lactic acid aqueous solution. 2 under nitrogen flow
After heating to 00 ° C. and continuing the reaction for 15 hours, the product was taken out and cooled and solidified. The obtained solid was pulverized to obtain a powdery polymer.

10 g of the aspartic acid-lactic acid copolymer obtained in Preparation Example 1 was added to 90 g of polybutylene succinate adipate (PBSA) having a weight average molecular weight Mw of 155,000 by chloroform-based GPC, and a small kneader was used. Blended at 180 ° C. for 5 minutes. The obtained PBSA composition was hot pressed at 180 ° C. to prepare a film.

Mw of the obtained PBSA composition was 106,000. The film had a tensile strength of 20 MPa and a tensile modulus of 322 MPa, and a flexible and high strength film was obtained.
This PBSA composition film was immersed in distilled water and kept at 35 ° C. in a thermostatic bath. The film was taken out every predetermined period and dried, and Mw (chloroform GPC) was measured. The Mw of the films after 1 week, 2 weeks, 3 weeks, and 4 weeks after immersion were 73,000, 65,000, 51,000, and 44,000, respectively. It broke. By using PBS and an aspartic acid-lactic acid copolymer composition, hydrolysis was effectively promoted.

A hot press film was obtained in the same manner as in Example 1 except that 90 g of polybutylene succinate adipate (PBSA) and 10 g of the aspartic acid-lactic acid copolymer obtained in Preparation Example 2 were used.

Mw of the obtained PBSA composition was 105,000. The film had a tensile strength of 22 MPa and a tensile modulus of 385 MPa, and a flexible and high strength film was obtained.
This PBSA composition film was immersed in distilled water in the same manner as in Example 1, and Mw (chloroform GPC) was measured.

After 1 week of immersion, 2 weeks, 3 weeks, and 4 weeks, the Mw of the film was 83,000, 70000, 50,000, 48,000, respectively. It broke. By using PBSA and an aspartic acid-lactic acid copolymer composition, hydrolysis was effectively promoted.

A hot press film was obtained in the same manner as in Example 1 except that 90 g of polybutylene succinate adipate (PBSA) and 10 g of the aspartic acid-lactic acid copolymer obtained in Preparation Example 3 were used.

Mw of the obtained PBSA composition was 106,000. The film had a tensile strength of 21 MPa and a tensile modulus of 443 MPa, and a flexible and high-strength film was obtained.
This PBSA composition film was immersed in distilled water in the same manner as in Example 1, and Mw (chloroform GPC) and tensile strength at break were measured.

The Mw of the films after 1 week, 2 weeks, 3 weeks, and 4 weeks after immersion were 90000, 84,000, 80,000, and 77,000, respectively. The breaking strength was 12 MPa. By using PBSA and an aspartic acid-lactic acid copolymer composition, hydrolysis was effectively promoted.

A hot press film was obtained in the same manner as in Example 1 except that 95 g of polybutylene succinate adipate (PBSA) and 5 g of the aspartic acid-lactic acid copolymer obtained in Preparation Example 1 were used.

Mw of the obtained PBSA composition was 13 million. The film had a tensile strength of 22 MPa and a tensile modulus of 360 MPa, and a flexible and high strength film was obtained.
This PBS composition film was immersed in distilled water in the same manner as in Example 1, and Mw (chloroform GPC) was measured.

  The Mw of the film after one week of immersion and two weeks later were 103,000 and 87,000, respectively, and hydrolysis was effectively promoted.

A hot press film was obtained in the same manner as in Example 1 except that 90 g of polybutylene succinate adipate (PBSA) and 10 g of the aspartic acid-lactic acid copolymer obtained in Preparation Example 4 were used.

Mw of the obtained PBSA composition was 111,000. The film had a tensile strength of 20 MPa and a tensile modulus of 367 MPa, and a flexible and high strength film was obtained.
This PBSA composition film was immersed in distilled water in the same manner as in Example 1, and Mw (chloroform GPC) was measured.

  The Mw of the film after one week of immersion and two weeks later was 82,000 and 67,000, respectively, and hydrolysis was effectively promoted.

A hot press film was obtained in the same manner as in Example 1 except that 95 g of polybutylene succinate adipate (PBSA) and 5 g of the aspartic acid-lactic acid copolymer obtained in Preparation Example 4 were used.

Mw of the obtained PBSA composition was 13 million. The film had a tensile strength of 23 MPa and a tensile modulus of 363 MPa, and a flexible and high-strength film was obtained.
This PBSA composition film was immersed in distilled water in the same manner as in Example 1, and Mw (chloroform GPC) was measured.

  The Mw of the film after one week of immersion and two weeks later was 105,000 and 85,000, respectively, and hydrolysis was effectively promoted.

  20 g of the aspartic acid-lactic acid-butylene succinate copolymer obtained in Preparation Example 5 was added to 80 g of polybutylene succinate adipate (PBSA) having a weight average molecular weight Mw of 150,000 by chloroform-based GPC. Blended at 180 ° C. for 5 minutes using a kneader. The obtained PBSA composition was hot pressed at 180 ° C. to prepare a film.

Mw of the obtained PBSA composition was 99,000. The film had a tensile strength of 21 MPa and a tensile modulus of 392 MPa, and a flexible and high-strength film was obtained.
This PBSA composition film was immersed in distilled water in the same manner as in Example 1, and the tensile strength and Mw (chloroform GPC) were measured.

  The Mw of the films after 1 week, 2 weeks, 3 weeks, and 4 weeks after immersion were 90000, 84,000, 77,000, and 68,000, respectively. The breaking strength was 14 MPa. By using PBSA and an aspartic acid-lactic acid-butylene succinate copolymer composition, hydrolysis was effectively promoted.

[Comparative Example 1]
A polybutylene succinate adipate (PBSA) having a weight average molecular weight Mw of 155,000 by chloroform-based GPC was obtained using a small kneader in the same manner as in Example 1 except that no aspartic acid-lactic acid copolymer was added. After melt-stirring at 180 ° C. for 5 minutes, a film was prepared by hot pressing at 180 ° C.

The Mw of the PBSA film was 1490,000. The film had a tensile strength of 25 MPa and a tensile modulus of 416 MPa, and a flexible and high strength film was obtained.
This PBSA composition film was immersed in distilled water in the same manner as in Example 1, and the tensile strength and Mw (chloroform GPC) were measured.

  The Mw of the film after 1 week, 2 weeks, 3 weeks, and 4 weeks after immersion was 145,000, 138,000, 138,000, and 136,000, respectively, and the decrease in molecular weight was slow. One month later, the tensile strength at break was 23 MPa, and the strength hardly decreased.

Poly L-lactic acid (PLA) having a weight average molecular weight Mw of 1290,000 by chloroform GPC
) To 95 g, 5 g of the aspartic acid-lactic acid copolymer obtained in Preparation Example 4 was added, and blended at 200 ° C. for 5 minutes using a small kneader. The obtained PLA composition was hot-pressed at 190 ° C. to prepare a film.

The obtained PLA composition film was colorless and transparent, and Mw was 108,000. The tensile strength of the film was 61 MPa, and the tensile modulus was 1.1 GPa, which was almost the same as the appearance and mechanical properties of the PLA film to which no aspartic acid-lactic acid copolymer was added.

  This PLA composition film was immersed in a phosphate buffer having a pH of 7.3 and kept at 37 ° C. in a thermostatic bath. The film was taken out and dried every predetermined period, and the tensile strength and Mw (chloroform GPC) were measured.

  The film gradually became white and opaque as the immersion time passed. The tensile strengths of the film after 1 month, 2 months, 3.5 months, and 5 months were 48 MPa, 40 MPa, 26 MPa, and 0 MPa, respectively (the film was fragile and could not be measured). Moreover, Mw of the film after 1 month, 2 months, 3.5 months, and 5 months was 87,000, 75,000, 51,000, and 45,000, respectively.

By making polylactic acid into a composition blended with aspartic acid-lactic acid copolymer,
The hydrolysis rate was effectively accelerated.
[Comparative Example 2]
A film was prepared by hot pressing PLA in the same manner as in Example 8 except that the aspartic acid-lactic acid copolymer was not added.

The PLA film was colorless and transparent, and the Mw was 98,000. The film had a tensile strength of 58 MPa and a tensile modulus of 1.1 GPa.
This PLA film was immersed in a phosphate buffer solution having a pH of 7.3 in the same manner as in Example 8 and maintained at 37 ° C. in a thermostatic bath. The film was taken out and dried every predetermined period, and the tensile strength and Mw (chloroform GPC) were measured.

  The tensile strengths of the films after 1 month, 2 months, 3.5 months, and 5 months were 62 MPa, 58 MPa, 57 MPa, and 55 MPa, respectively. The film remained colorless and transparent, and the appearance was hardly changed.

  After 1 month, 2 months, 3.5 months, and 5 months, the Mw of the film was 92,000, 90,000, 87,000, and 80000, respectively, and the decrease in molecular weight was slow. It was a thing.

  A sheet having a thickness of 0.5 mm was prepared from the composition obtained in Example 1 and rolled into a cylindrical shape to produce a cylindrical tampon applicator having a diameter of 10 mm and a length of 50 mm.

  From the above examples, the biodegradable composition used in the present invention has hydrolyzability and biodegradability, and the biodegradable composition is a hot melt adhesive, an aqueous paper coating composition, Peelable adhesive material, thermal transfer medium, fiber, non-woven fabric, film, sanitary ware packaging material, food packaging material, protective film, porous film, agricultural and horticultural material, pet waste disposal material, sustained-release drug, electrical equipment casing , Processing aids, civil engineering and building materials, cleaning articles, wet sheets, leisure goods, toys, educational materials, acid absorbents, and alkaline absorbents.

Claims (27)

A block or graft copolymer (A) having a structural unit derived from a polyamino acid as a hydrophilic segment (a-1) and a structural unit derived from a degradable polymer as a hydrophobic segment (a-2) A biodegradable composition comprising   The biodegradable composition according to claim 1, further comprising a degradable resin (B).   A biodegradable molded article using the biodegradable composition according to claim 1.   A hot melt adhesive using the biodegradable composition according to claim 1.   An aqueous paper coating composition using the biodegradable composition according to claim 1.   An easily peelable pressure-sensitive adhesive material using the biodegradable composition according to claim 1.   A thermal transfer medium using the biodegradable composition according to claim 1.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a fiber.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a non-woven fabric.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a film.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a packaging material for sanitary goods.   A biodegradable molded article according to claim 3, which is a food packaging material.   A biodegradable molded article according to claim 3, which is a protective film.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a porous film.   A biodegradable molded article according to claim 3, which is an agricultural and horticultural material.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a pet waste disposal agent.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a sustained-release drug.   A biodegradable molded article according to claim 3, which is a casing of an electronic device.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a processing aid.   A biodegradable molded article according to claim 3, which is a civil engineering and building material.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a cleaning article.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a wet sheet.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a leisure article.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a toy.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is a teaching material.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is an acid absorbent.   A biodegradable molded article according to claim 3, wherein the biodegradable molded article is an alkali absorbent.