JPH11335475A - Production of biodegradable resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress lowering of biodegradability due to lipid and produce the subject molded product excellent in biodegradability and useful for disposable products in good productivity without purification of a raw material resin by molding a biodegradable resin containing an impurity lipid and then, washing the molded resin with a solvent. SOLUTION: A biodegradable resin composition containing a lipid (e.g. phospholipid) which is immiscible in a biodegradable resin [e.g. polyhydroxybutylate- based copolymer containing 70-95 mol.% recurring unit of the formula based on 3-(R)-hydroxybutylate] is molded and the resultant molded product is brought into contact with a solvent (e.g. a neutral organic solvent having >=20.3 MPa<1/2> or <=18.2 MPa<1/2> solubility parameter, specifically a 1-3C alcohol, etc.), to remove a lipid oozed on the surface of the molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biodegradable resin molded product which is decomposed by the action of microorganisms, and more particularly to a method for producing a molded product made of a polyhydroxybutyrate copolymer.

[0002]

2. Description of the Related Art In recent years, the demand for plastics that are light and strong and have excellent moldability has been increasingly demanded, and their production has been increasing to 14 million tons per year. Along with this, the amount of plastics to be discarded has also increased significantly, and the problem of plastic waste has been attracting attention as one of the serious social problems.

[0003] The main methods currently being used for treating plastic waste are landfill and incineration. However, in the landfill process, the bulky plastic material not only shortens the life of the landfill, but also hinders the stabilization of the landfill. On the other hand, in the case of incineration, the incinerator is easily damaged due to high combustion heat.

[0004] Biodegradable plastics have attracted attention as one of the measures against such plastic waste problems. Biodegradable plastics are materials that can be decomposed by microorganisms and have the property of decomposing into carbon dioxide and water by the action of microorganisms in an appropriate decomposition environment.

[0005] Among many types of biodegradable plastics, polyhydroxybutyrate resins (hereinafter abbreviated as P
HB) is a microbial-produced, high molecular weight aliphatic polyester that many types of microorganisms accumulate in their cells in the form of granules as energy storage materials.
Since PHB is a natural substance that is biosynthesized in the cells of microorganisms, the distribution of degrading microorganisms in all environments and excellent biodegradation at all levels of enzymes, microorganisms and fields Sex has been reported. Furthermore, in PHB, there is no polymerization initiator such as an organometallic compound used in the synthesis of a chemically synthesized plastic. Therefore, it is strongly desired that PHB be developed as an environmentally safe plastic material.

As described above, PHB is an excellent material in biodegradability as compared with many other biodegradable plastic materials. Because the polymer is a microbial-produced aliphatic polyester that the microorganisms accumulate in their cells in the form of granules as an energy storage material, the separation of PHB granules from within the microbial cells generally requires the use of enzymes. Have been implemented. in this case,
The separated granules generally contain proteins and trace amounts of lipids (hereinafter simply referred to as "impurity lipids"). Biochemistry (R. Griebel, Z. Smith,
and JM Merrick, Biochemistry, 7, 3676-
3681 (1968)}.

The present inventors have conducted various studies on the effects of the above-mentioned impurity lipids on various physical properties of PHB.
The effect was found to differ greatly depending on the type of PHB. That is, in the case of the PHB homopolymer and the PHB copolymer having a low content of the repeating unit other than 3- (R) -hydroxybutyrate, the impurity lipid has a function of accelerating the biodegradability. It has been clarified that the impurity lipid has a function of inhibiting the biodegradability of a PHB-based copolymer having a relatively high content of repeating units other than (R) -hydroxybutyrate.

Numerous types of the latter PHB-based copolymers have been synthesized for the purpose of improving molding processability and imparting flexibility to molded products.
In many cases, HB-based copolymers are more suitably used. Therefore, reduction of the biodegradability of these PHB-based copolymers is a serious problem, and it is desired to solve this problem.

The above-mentioned impurity lipids can be removed by dissolving the granules in a solvent and then purifying by adding a poor solvent to precipitate PHB. However, Y. Kawaguchi and Y. Doi, FEMS Microbiology
Letters, Vol. 70, 151-156 (1990)}, the recovery of PHB in such a purification is generally low, and there is a problem that the productivity is reduced by the purification.

[0010]

Therefore, the present invention relates to
PHB-based copolymer having a relatively high content of repeating units other than-(R) -hydroxybutyrate (hereinafter referred to as HP
Also called HB-based copolymer. ), A method of producing a molded article having high biodegradability without particularly performing polymer purification, which leads to a decrease in productivity, for a biodegradable resin whose biodegradability decreases due to the influence of impurities. Aim.

[0011]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that H containing impurity lipid
-It has been found that when the obtained molded body is washed with a solvent after molding the PHB-based copolymer, the biodegradability is improved. After further study, the above HP
It was confirmed that the low biodegradability of the HB-based copolymer had a large effect on the impurity lipid oozing on the surface of the molded product, and that the impurity lipid was removed from the surface of the molded product by the above washing. Thus, the present invention has been completed.

That is, the present invention provides a method for molding a biodegradable resin composition containing a lipid immiscible with the biodegradable resin.
A method for producing a biodegradable resin molded body, which comprises contacting the obtained molded body with a solvent to remove the lipid oozing out on the surface of the molded body.

In the above method, the biodegradable resin is, for example, a polyhydroxybutyrate copolymer having a repeating unit content of 70 to 95 mol% based on 3- (R) -hydroxybutyrate. In this case, the lipid that is immiscible with the biodegradable resin is, for example, a phospholipid (particularly, a diacyl ester type glycerophospholipid), and the content is, for example, 0.001% by weight or more. Also,
In this system, a solvent preferably used is one having 1 carbon atom.
The solubility parameter of which is 2 to 3 alcohols, etc.
0.3 MPa ^1/2 or more, or 18.2MPa ^1/2 or less of neutral organic solvent.

The biodegradable resin has a content of repeating units based on 3- (R) -hydroxybutyrate of 70 to 95.
In the case described above, which is a polyhydroxybutyrate-based copolymer in which the amount is mole%, the impurity lipid contained in the copolymer is discharged from the crystalline phase during the crystallization process during molding, and as a result, It is thought that the biodegradation was suppressed because the exuded impurity lipids oozed to the body surface and inhibited the contact between the copolymer surface and the degrading microorganisms and degrading enzymes. It is considered that the biodegradability was restored due to the removal.
Such a mechanism is not limited to the above-mentioned specific resin system, but is considered to be general.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The biodegradable resin composition used in the production method of the present invention is not completely miscible with the biodegradable resin and the biodegradable resin. (Poor) lipid-containing compositions.

Here, the biodegradable resin is not particularly limited as long as it is a resin having biodegradability. Examples of the biodegradable resin that can be used in the present invention include poly {3- (R) -hydroxybutyrate-co-3- (R) -hydroxyvalerate} and poly {3- (R) -hydroxybutyrate. −
co-3-hydroxypropionate}, poly {3-
Poly (hydroxybutyrate) copolymers such as (R) -hydroxybutyrate-co-3- (S) -hydroxybutyrate}; poly (3-hydroxypropionate), poly (4-hydroxybutyrate), Poly (ω-hydroxyalkanoate) such as poly (ε-caprolactone)
And polycondensation copolymers or cyclic acid anhydrides of diols with dibasic acids such as poly (ethylene succinate), poly (butylene succinate), poly (butylene adipate), poly (butylene succinate / adipate) Ring-opening copolymers with cyclic ethers; copolymers of trimethylene carbonate with cyclic lactones, cyclic acid anhydrides, or cyclic ethers; lactide and cyclic lactones, cyclic acid anhydrides, or cyclic ethers And the like.

Among these biodegradable resins, 3- (R)
A polyhydroxybutyrate-based copolymer in which the content of repeating units based on -hydroxybutyrate is 70 to 95 mol% (hereinafter, also referred to as the present PHB-based copolymer)
Is a polymer that is generally synthesized by a fermentation synthesis method using a microorganism and is accumulated as an energy storage substance in the cells of the microorganism, and is widely known to have excellent biodegradability. It has been confirmed that there is a lipid derived from a microbial cell substance that is immiscible with the PHB-based copolymer.

The present PHB-based copolymer refers to 3- (R) -hydroxybutyrate represented by the following formula 1 among all repeating units (hereinafter also referred to as monomer units) constituting the copolymer. Based monomer unit content of 70
It is a PHB-based copolymer having a content of about 95 mol%.

[0019]

Embedded image

In the formula, C ^* represents an asymmetric carbon atom, and the configuration of each substituent bonded to the asymmetric carbon atom is (R)-
Body. The monomer unit other than the monomer unit represented by the above formula 1 in the present PHB-based copolymer is not particularly limited, but is preferably a comonomer unit represented by the following formula 2.

[0021]

Embedded image

In the formula, R ¹ is a hydrogen atom or a linear or branched aliphatic alkyl group having 1 to 10 carbon atoms, and C ^* represents an asymmetric carbon atom. The configuration of each substituent to be bonded is (R)-and (S) -form, and when R ₁ has 1 carbon atom, the configuration is (S)-
R ₂ is a linear alkylene group having 0 to ₂ carbon atoms.コ Specific examples of the comonomer unit represented by the above formula 2 include (R)-and (S) -lactate, glycolate, 3-hydroxypropionate, 3- (S) -hydroxybutyrate, (R)-and (S) -hydroxyvalerate, 3- (R)-and (S) -hydroxyhexanoate, 3- (R)-and (S) -hydroxyoctanoate, 3- (R) Monomer units based on-and (S) -hydroxydecanoate, 3- (R)-and (S) -hydroxydodeanoate, 4-hydroxybutyrate, and the like. These comonomer units are
They may be present alone or as a mixture.

Among the above comonomer units, 3- (R)-wherein R ₁ is an ethyl group and the configuration is (R) -isomer.
A unit based on hydroxyvalerate is more preferably used in terms of improvement in biodegradability by the washing treatment of the present invention, easy availability, and the like.

The lipid which is the other component contained in the biodegradable resin composition used in the production method of the present invention is a lipid which is immiscible with the biodegradable resin used (hereinafter, also referred to as the present lipid). It is not particularly limited.

Examples of such lipids include, for example, undecanoic acid, tridecanoic acid, myristic acid, pentadecanoic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, saturated monohydroxy acids and the like having 4 to 34 carbon atoms. Fatty acids such as trioleyl glycerin, trilinoleyl glycerin, dipalmityl glycerin, monooleyl glycerin, etc .; acyl glycerols which are esters of glycerin with the above fatty acids; aliphatic alcohols such as cetyl alcohol; ergosterol etc. Sterols; hydrocarbons such as squalene; L-α-phosphatidylcholine, L
-Diacyl ester-type glycerophospholipids such as α-phosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol, phosphatidylglycerol phosphate, cardiolipin, phosphatidylinositol, phosphatidic acid; lyso-type glycerophospholipids such as semilysobisbisphosphatidic acid; ceramide phosphoethanol Sphingophospholipids such as amines; neutral glyceroglycolipids such as monoglycosyldiacylglycerin, diglycosyldiacylglycerin, triglycosyldiacylglycerin, and tetraglycosyldiacylglycerin; acidic glyceroglycolipids such as glycoglycerophospholipid. .

As described above, the above-mentioned lipid inhibits biodegradability when present on the surface of the molded biodegradable resin, but is sufficiently mixed with the biodegradable resin and does not exude after molding ( Those that do not bloom are not particularly problematic even if they are contained.

The above-mentioned lipids are generally used in the production of biodegradable resins such as fermentation synthesis, except for fatty acids, aliphatic alcohols or acylglycerins, which are partially added as a lubricant during molding. It is included as an impurity at the stage and is not actively added to the biodegradable resin. For this reason, the content of the present lipid in the biodegradable resin composition used in the production method of the present invention is a property determined by the production and purification conditions of the biodegradable resin to be used. The content of lipids contained in the biodegradable resin after a typical purification step is from 0.01 to
It is about 1.0% by weight. In addition, regarding fatty acids, aliphatic alcohols, or acylglycerins used as the lubricant, 0.1 to 3 depending on lack of lubrication.
In some cases, about weight% is positively added before molding.

Whether or not the above-mentioned lipid is miscible with the biodegradable resin cannot be specified unconditionally because it depends on the type of the biodegradable resin to be used, but it is easily confirmed by the following method. I can do it.

That is, after forming a biodegradable resin containing lipid as an impurity into a form having a large surface area such as a film,
After increasing the temperature to allow blooming and leaving the molded product to stand for a certain period of time, the surface of the molded product can be washed with a solvent and analyzed by analyzing the lipid component contained in the washing solution.

Among the above-mentioned various lipids, phospholipids such as diacyl ester type glycerophospholipids may exude (bloom) on the surface of the molded body without being mixed with the present PHB copolymer by such a method. Has been confirmed.

In the production method of the present invention, after molding the biodegradable resin composition, the molded body is brought into contact with a solvent to remove the lipid leached on the surface of the molded body from the biodegradable resin. Is removed without substantial dissolution.

At this time, the molding method of the biodegradable resin composition is not particularly limited, and a molding method generally known as a plastic processing and molding means can be used. Representative molding methods include, for example, a casting method of dissolving or dispersing the biodegradable resin composition in a solvent and then evaporating the solvent, and a melt molding method generally used for molding a thermoplastic resin. Examples of the method include an extrusion molding method, an injection molding method, a blow molding method, a calendar molding method, a spun bond method, a melt bond method, a roll stretching method, an inflation method, and a tenter method. The biodegradable resin composition,
A molded article having a desired shape is obtained according to the employed molding method and conditions. Specific forms of the molded body, for example, films, plates, injection molded products of various shapes such as bottles,
Extrusion molded products, blow molded products, foam molded products, fibers, non-woven fabrics and the like can be mentioned.

When performing the above-mentioned molding, the biodegradable resin composition may contain a heat stabilizer, an antioxidant, a release agent, an ultraviolet ray inhibitor, depending on the use and purpose of the obtained molded article.
Coloring agents, reinforcing agents, surfactants, lubricants, fillers, foaming agents,
Auxiliary components such as plasticizers can also be added.

In the production method of the present invention, the molded body obtained by the above-mentioned method is brought into contact with a solvent to remove lipids oozing out on the surface of the molded body. Is not particularly limited as long as it dissolves lipid and does not substantially dissolve biodegradable resin. Such a solvent may be appropriately determined depending on the biodegradable resin to be used and the type of the present lipid contained in the copolymer.

For example, when the biodegradable resin to be used is the present PHB-based copolymer and the present lipid is a phospholipid such as a diacyl ester type glycerophospholipid, the range of the solubility parameter (hereinafter, also referred to as SP) is used. Is 20.3MPa
^1/2 or more, or 18.2MPa ^½ or less of the organic solvent neutral are preferably used.

Here, the solubility parameter (SP) is
It is a value that can be experimentally obtained according to the following formula, and the value is based on Polymer Handbook, 3rd edition, edited by J. Brah for many solvents.
ndrup and EH Immergut, AWiley Interscience Publ
ication (1989)).

(SP) ² = (ΔE) / V = {(ΔH) -R
T} / V = d {(ΔH) −RT} / M where ΔE is evaporation energy (cal / mol), d is density (g / cc), and V is molar volume (cc / mol). ) And ΔH
Is the latent heat of evaporation (cal / mol), T is the absolute temperature (K), and R is the gas constant (cal / molK).が The above solubility parameter range is 20.3 MPa ^1/2
Specific examples of the above or a neutral organic solvent of 18.2 MPa ^1/2 or less include methanol (29.7), ethanol (26.0), and n-propyl alcohol (24.
4), isopropyl alcohol (23.5), n-butyl alcohol (23.3), ethylene glycol (2
9.9), alcohols such as diethylene glycol (24.8); ketones such as acetone (20.3); fragrances such as toluene (18.2), xylene (18.0), ethylbenzene (18.0) Aromatic solvents; heterocyclic compounds such as γ-butyrolactone (25.8); hexane (1
4.9), pentane (14.3), heptane (15.
1), octane (15.6), cyclohexane (16.
And chain and cyclic aliphatic hydrocarbons such as 8).
Among these organic solvents, cleaning efficiency, easy availability,
From the viewpoint of ease of desolvation after washing and safety, etc.
~ 3 alcohols are more preferably used. These organic solvents may contain 50% by weight or less of water.

[0038] The method of bringing the above molded body into contact with a solvent is not particularly limited as long as the present lipid oozing on the surface of the molded body can be removed. As such a method, for example, a method of dipping a molded body in a tank containing a solvent,
A method for washing a molded body by spraying a solvent in a shower shape, a method for immersing the molded body in a bath containing a solvent for a predetermined time, a gel containing a solvent, a woven fabric, or a nonwoven fabric containing the surface of the molded body. And a method of wiping using a sheet or the like. Among these washing methods, the above method or the above method is more preferably used from the viewpoint of operability.

The contact conditions in each of the above contacting methods are individually selected according to the shape of the molded article, the type of the biodegradable resin or the present lipid constituting the molded article, and the method to be adopted. Regarding the temperature of the solvent at the time of contact, the higher the temperature, the higher the efficiency of removing the present lipid.However, if the temperature is too high, it may adversely affect the shape and physical properties of the molded body. The temperature is preferably lower than the melting point, especially when the biodegradable resin is a crystalline resin. Usually, a range of 0 ° C to 100 ° C, more preferably 10 ° C to 50 ° C is preferably employed. Regarding the contact time, there is a slight difference depending on the contact method, but usually,
Sufficient effects can be obtained if it is performed for several seconds to several minutes.

When the molded body is brought into contact with the solvent as described above, lipids oozing out on the surface of the molded body are removed from the surface in a form dissolved in the solvent, and as a result, the biodegradable resin inherently contained in the biodegradable resin is obtained. Sex develops.

The biodegradability of the molded product obtained by the production method of the present invention can be evaluated by the following method. That is, a PHB-decomposing enzyme is allowed to act on a molded article formed from a PHB-based copolymer in an aqueous medium, and enzymatic degradation evaluation is performed to track the decrease in the weight of the molded article and the increase in the amount of solubilized organic matter in the aqueous medium. Method, Decomposed microorganisms are allowed to act on a molded article molded from a PHB-based copolymer in an aqueous medium containing nutrients of microorganisms, thereby reducing the weight of the molded article, absorbing oxygen, generating carbon dioxide, etc. Microbial degradability evaluation method to track the weight loss, etc., by embedding the molded body formed from the PHB-based copolymer in soil or in a water area such as a river, or in compost, and tracking the weight loss etc. Can be evaluated.

[0042]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 [Preparation of Film] Poly consisting of 84.3 mol% of a unit based on 3- (R) -hydroxybutyrate and 15.7 mol% of a unit based on 3- (R) -hydroxyvalerate. A hydroxybutyrate-based copolymer (number average molecular weight: 219000, molecular weight distribution: 2.03) was dissolved in chloroform, and this was precipitated in n-heptane to prepare a purified polyhydroxybutyrate-based copolymer. 2 g of this purified polyhydroxybutyrate-based copolymer was
The solution was dissolved in 1 l of chloroform, and 0.02 g of phosphatidylcholine was added to the solution and dissolved. This solution was poured into a flat petri dish, and the solvent was vaporized at room temperature to obtain a lipid-containing film. The film was dried under vacuum for 24 hours and then equilibrated at room temperature for 4 weeks. The thickness of the produced cast film was about 70 microns.

The prepared cast film was melted at 195 ° C. and then cooled to prepare a recrystallized film.
Microscopic observation of the surface of the recrystallized film confirmed that spots were formed on the surface of the film due to leaching of phosphatidylcholine.

[Washing with Solvent] Methanol (SP = 2)
The recrystallized film was immersed in a beaker containing 9.7 MPa ^1/2 ) for about 1 minute to wash and remove phosphatidylcholine exudation spots on the surface.

[Evaluation of enzyme degradation]
The sample was cut into a size of mx1 cm and used as a test sample. The test sample weighed 7.5 mg. Degradation enzymes are Alcaligenes f.
aecalis ) It was separated and purified from T1. Enzymatic degradation test
1 ml of phosphate buffer containing 1 mg of enzyme (pH 7.
4) The test was performed at 37 ° C. The rate of enzymatic degradation was evaluated using the amount of weight loss of the film after 5 hours as an index. As a result, a 2.6 mg weight loss was observed.

This weight loss value is almost the same as the weight loss value (2.7 mg) obtained when the same measurement was carried out using a purified polyhydroxybutyrate-based copolymer to which no phosphatidylcholine was added.

Comparative Example 1 A film was prepared and the enzymatic degradation was evaluated in exactly the same manner as in Example 1 except that the [washing with solvent] operation was not performed. As a result, a weight reduction of 1.0 mg was observed.

From the results of Example 1 and Comparative Example 1, it is clear that the enzymatic degradability is significantly improved by solvent washing of the melt-molded film.

Examples 2 to 3 Table 1 shows polyhydroxybutyrate-based copolymers comprising monomer units based on 3- (R) -hydroxybutyrate and monomer units based on 3- (R) -hydroxyvalerate. Except for using the indicated copolymer, a film was prepared, washed with a solvent, and evaluated for enzymatic degradation in the same manner as in Example 1. The measurement results are also shown in Table 1.

[0051]

[Table 1]

Comparative Examples 2-3 A film was prepared and the enzymatic degradability was evaluated in exactly the same manner as in Examples 2-3 except that the above-mentioned "washing with a solvent" was not performed. The measurement results are also shown in Table 1.

From the results shown in Table 1, it is clear that the enzymatic degradability is significantly improved by the solvent washing of the film molded product.

Examples 4 to 6 In the same manner as in Example 1 except that the solvents shown in Table 2 were used,
Film preparation, solvent cleaning, and enzymatic degradation evaluation were performed. The measurement results are also shown in Table 2. From the comparison with the result of Comparative Example 1, it is clear that the enzymatic degradability is significantly improved by the solvent washing of the film molded body.

[0055]

[Table 2]

Examples 7-9 PHB polymers produced by microorganisms were purified by reprecipitation with chloroform / n-heptane system as in Example 1,
Further, a recrystallized film was prepared, washed with a solvent, and evaluated for enzymatic degradability in the same manner as in Example 1 without newly adding a lipid component. The measurement results are also shown in Table 3.

[0057]

[Table 3]

As a result of microscopic observation of the surface of the recrystallized film prepared in each of the examples, spot formation was observed on the film surface due to the exudation of lipid components.

Comparative Examples 4 to 6 Film preparation and enzymatic degradation evaluation were performed in exactly the same manner as in Examples 7 to 9 except that the above-mentioned "washing with solvent" operation was not performed. The measurement results are also shown in Table 3.

From the results shown in Table 3, it is clear that the enzymatic degradability is significantly improved by the solvent washing of the film molded product.

[0061]

Industrial Applicability The present invention relates to a biodegradable plastic which is expected to be an effective measure against the problem of plastic waste, and in particular, polyhydroxybutyrate which is fermentatively synthesized from renewable resources and has excellent processability and flexibility. With respect to the system copolymer, a molded article having biodegradability inherent to the raw material polymer can be produced. In addition, in the production method of the present invention, since it is not necessary to use a purified raw material polymer, a loss at the time of purification of an expensive biodegradable resin can be reduced.

According to the present invention, disposable plastic products, which are regarded as a major cause of the plastic waste problem, such as shopping bags, disposable diapers, sanitary articles, agricultural films, packaging materials, cushioning materials, and composting garbage. It becomes easier to apply the biodegradable resin to compost bags and triangular corners used in compost systems.

Claims (6)

[Claims] After molding a biodegradable resin composition containing a lipid that is immiscible with a biodegradable resin, the resulting molded body is brought into contact with a solvent to remove the lipid oozing out on the surface of the molded body. A method for producing a biodegradable resin molded product, comprising: removing the molded product. 2. A biodegradable resin having a repeating unit content of 70 to 9 based on 3- (R) -hydroxybutyrate.
The method for producing a biodegradable resin molded article according to claim 1, wherein the polyhydroxybutyrate-based copolymer is 5 mol%. 3. The method for producing a biodegradable resin molded article according to claim 2, wherein the lipid that is immiscible with the biodegradable resin is a phospholipid. 4. The content of repeating units based on phospholipids and 3- (R) -hydroxybutyrate is 70 to 95.
After molding a biodegradable resin composition containing a mol% polyhydroxybutyrate-based copolymer, the resulting molded product is substantially dissolved in the polyhydroxybutyrate-based copolymer, but the phospholipid is not dissolved. 3. A method for producing a biodegradable resin molded body, comprising washing with a solvent capable of dissolving. 5. The method according to claim 1, wherein the solvent has a solubility parameter of 2
0.3 MPa ^1/2 or more, or 18.2MPa ^1/2 or less of the method for manufacturing the biodegradable resin molded body according to any one of claims 1 to 4, characterized in that a neutral organic solvent . 6. The method for producing a molded biodegradable resin according to claim 5, wherein the neutral organic solvent is an alcohol having 1 to 3 carbon atoms.