JP2006206901A - Modifier for biodegradable resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable resin composition which, while maintaining its molecular weight even when mixed and kneaded with a modifier under heating, is excellent in softness, pressure-sensitive adhesiveness, and adhesiveness and has improved compatibility with other materials to be compounded. <P>SOLUTION: The biodegradable resin composition, so excellent in softness, compatibility with other materials, pressure-sensitive adhesiveness, and adhesiveness as not to be obtainable by a conventional technique, is obtained by compounding a urethane compound which is obtained by reacting the component A (an alkylene oxide adduct of a compound having a hydroxy group) with the component B (a compound having an isocyanate group). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention provides a biodegradable resin modifier capable of imparting flexibility to a molded product or the like while maintaining the molecular weight of the biodegradable resin and improving compatibility with other materials to be blended. In particular, the present invention relates to a modifier for polylactic acid resin, which is a plant-derived renewable resource.

  Plastics such as polypropylene, polyethylene, and polyvinyl chloride, which are made from petroleum and other fossil resources, are transformed into food packaging films, electrical appliances, industrial materials, etc., and are indispensable for our lives. . However, it is well known that such plastics are almost non-biodegradable and remain semi-permanent in nature after they are no longer needed, which has a major impact on the ecosystem and leads to environmental destruction in various ways. Is the fact of

Under such circumstances, biodegradable resins are attracting attention. Among them, plants that are biodegradable and are trying to convert from plastics derived from fossil resources are made from plants. That is, it is a plant-derived biodegradable resin.
Of particular interest in recent years is the polylactic acid-based resin whose production volume is dramatically increasing. The social background in which polylactic acid-based resins are attracting attention is that there is a need to conserve limited fossil resources and a material recycling social system that aims to recycle waste resin processed products. Can be mentioned. While various plastics that use fossil resources as raw materials are greatly out of circulation, polylactic acid resins synthesized from sugars obtained from plants such as corn or potato or lactic acid obtained by fermenting them are recycled. This is because it is expected to be able to construct a material circulation type system that has become an important proposition.

  The raw material of polylactic acid resin is synthesized from sugars obtained from cereals such as corn or potato, which are renewable resources, or synthesized from lactic acid obtained by fermenting them. After being easily hydrolyzed and decomposed by microorganisms, it finally becomes water and carbon dioxide.

Biodegradable resins such as polylactic acid have high rigidity and lack suitability as films, packaging materials, and molded article materials that require flexibility and workability. Therefore, it is generally necessary to soften the resin, and as a method therefor, (1) a blend of soft polymers, (2) copolymerization, (3) addition of a plasticizer, etc. can be considered. However, in the method (1), the resin to be blended is limited to a biodegradable resin having flexibility. Examples of such a resin include polycaprolactone, polybutylene succinate, and polyethylene succinate. Although already disclosed in Patent Document 1 and Patent Document 2, this method limits the softening degree of the biodegradable resin to the softening property of the resin used.

The method (2) is disclosed in Patent Document 3 and Patent Document 4, but must be changed from the biodegradable resin manufacturing process, and the resin physical properties are different from those in the case of manufacturing from a homopolymer. In addition, it is inevitable that the cost is disadvantageous.

Further, the method (3) is also disclosed in Patent Document 5, Patent Document 6, and Patent Document 7, all of which have merits and demerits in bleedability and flexibility, and are problematic in actual use.

JP-A-8-245866 JP-A-9-111107 JP 2002-193343 A WO99 / 45067 JP 2002-80703 A JP 2002-88173 A JP 2002-348451 A

The object of the present invention is to have excellent flexibility, adhesiveness, adhesion, and blend while maintaining the molecular weight even when the modifier is heated and kneaded under such circumstances. The object is to provide a biodegradable resin composition having improved compatibility with other materials.

As a result of diligent research to solve the above problems, the present inventors have blended a specific urethane compound into a biodegradable resin, while maintaining the molecular weight, flexibility, compatibility with other materials, adhesiveness The present inventors have found that an excellent biodegradable resin composition that cannot be obtained by the prior art in terms of property and adhesion can be obtained.

That is, the present invention relates to a biodegradable resin modifier comprising a urethane compound obtained by reacting an alkylene oxide adduct (component A) of a compound having a hydroxyl group with a compound having an isocyanate group (component B). .

By blending the urethane compound according to the present invention with a biodegradable resin, particularly polylactic acid, the resin has excellent flexibility and adhesiveness while maintaining the molecular weight without significant deterioration of physical properties or aging due to bleeding. It is possible to impart resin properties such as adhesion, adhesion, and compatibility with other materials, and processability.

The present invention is described in detail below.
Examples of the compound having a hydroxyl group in the present invention include various alcohols such as aliphatic saturated alcohols, aliphatic unsaturated alcohols, alicyclic alcohols, aromatic alcohols, heteroalicyclic alcohols, oils and fats derived from natural products having hydroxyl groups, and rosin. Examples thereof include aliphatic chain hydrocarbons having a hydroxyl group such as alcohols and alicyclic hydrocarbons, and also include polyhydric alcohols such as dihydric alcohols and trihydric alcohols, various secondary alcohols and tertiary alcohols. .

Specifically, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, amyl alcohol, decyl alcohol, lauryl alcohol, cetyl alcohol, ceryl alcohol, allyl alcohol, propavgyl alcohol, cyclopentanol, cyclohexanol, Monohydric alcohols such as benzyl alcohol, cinnamon alcohol, furfuryl alcohol, oleyl alcohol, cetyl alcohol, stearyl alcohol, ethyl lactate, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, butanediol, Neopentyl glycol, hexanediol, cyclohexanedimethanol, diethylene glycol, pentane Lumpur, do not may be mentioned include compounds having a hydroxyl group is limited to a molecule such as a reaction product of a polyhydric alcohol, more polyhydric alcohol and a fatty acid such as trimethylolpropane.

Addition of alkylene oxide to a compound having a hydroxyl group can be easily performed by using a catalyst as necessary at a reaction temperature of about 60 ° C. to 250 ° C. under pressure, but is particularly limited to this method. It is not a thing. The alkylene oxide is preferably added in an amount of 1 mol to 300 mol, more preferably 1 to 80 mol, per molecule of the compound having a hydroxyl group in the present invention. Specific examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and the like, and one or more of these can be added in combination. As the proportion of ethylene oxide increases, the compatibility with the resin increases, but the water resistance decreases. On the other hand, if the amount of propylene oxide or butylene oxide is large, the hydrophobicity increases, but the compatibility with the resin decreases. Therefore, the type of alkylene oxide to be used is appropriately selected according to the required performance. Moreover, when adding 2 or more types of alkylene oxides, the form may be either a block form or a random form, and it can select according to the products applied including an addition order, a use ratio, etc.

On the other hand, a reaction product of a polyhydric alcohol and a fatty acid can also be obtained by an esterification reaction by a known method. Here, as the polyhydric alcohol, those described above can be used, and the fatty acid is not particularly limited in carbon number, and may be either saturated or unsaturated, but generally octane. Fatty acids such as acid, nonanoic acid, decanoic acid, lauric acid, tridecanoic acid, stearic acid, isostearic acid, behenic acid, oleic acid, and rosin acid are preferred. These may be used in combination of a plurality of types for the purpose of improving the compatibility with other combined materials as required.

Examples of the compound having an isocyanate group include isocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, dodecane methylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate and the like. Examples thereof include urethane prepolymers that are derivatives of polyols having isocyanate groups.

The polyol used for the synthesis of the urethane prepolymer is a compound obtained by adding a catalyst to an active hydrogen-containing compound and adding an alkylene oxide such as ethylene oxide, propylene oxide or butylene oxide as necessary, specifically polyoxyethylene. In addition to glycol, polyoxypropylene glycol, polyoxyethylene propylene glycol, etc., ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, butanediol, neopentyl glycol, hexanediol, cyclohexanedimethanol, Polyethylene alcohols such as diethylene glycol, pentanediol, trimethylolpropane, ethylene oxide, propylene oxide, butylene Polyether polyols such as one or two or more adducts such as oxides, polyols such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethylene glycol, neopentyl glycol, glycerin or trimethylol propane, succinic acid, glutar Examples thereof include polyvalent saturated or unsaturated carboxylic acids such as acid, adipic acid, maleic acid, fumaric acid and phthalic acid, condensation products thereof with these acid anhydrides, and polyester polyols such as polycaprolactone polyol. These are mixed and used as necessary. These polyester polyols are further exemplified by adducts such as ethylene oxide and propylene oxide, and these polyol compounds are used alone or in combination.

By further reacting the polyol with an isocyanate, a compound having an isocyanate group at the terminal can be obtained. Prepolymers having polyfunctional isocyanate groups can also be synthesized and used. In addition, the alkylene oxide adduct (component A) of a compound having a hydroxyl group according to the present invention can also be used as a prepolymer raw material.

The urethane compound according to the present invention can be obtained by reacting the A component and the B component. In this reaction, it is desirable to adjust the water content in component A to 0.1% by weight or less, preferably 0.05% by weight or less, and CPR to 5 or less, preferably 1 or less. In general, the urethanization reaction is carried out in the range of 60 to 140 ° C. for about 2 to 10 hours. If the reaction proceeds slowly, a small amount of dibutyltin laurate or the like is added as a catalyst to promote the reaction. From the viewpoint of preventing gelation, it is preferable that the remaining isocyanate residue (NCO%) is 5% or less. NCO% can be measured based on JIS K1556. Any solvent may be used in this reaction.

Even if an isocyanate group remains, the stability can be improved by protecting the isocyanate group with a blocking agent. Known compounds can be used as the blocking agent. For example, oxime compounds (such as MEK oxime and MIBK oxime), lactams (such as ε-caprolactam), phenols (such as phenol and m-cresol), alcohols (such as methanol and ethanol), hydroxyl-containing ethers (methyl cellosolve, Butyl cellosolve), hydroxyl group-containing esters (ethyl lactate, amyl lactate, etc.), mercaptans (butyl mercaptan, hexyl mercaptan, etc.), acid amides (acetanilide, acrylic amide, etc.), imidazoles (imidazole, 2-ethylimidazole, etc.), Acid imides (succinimide, phthalimide, etc.) and a mixture of two or more of these may be mentioned. Of these, oxime compounds are preferred, and MEK oxime is particularly preferred. The amount of the blocking agent added is preferably 1.00 to 1.50 equivalents, particularly preferably 1.05 to 1.20 equivalents, relative to the remaining isocyanate groups. The reaction temperature when adding the blocking agent is usually 50 to 100 ° C. In the reaction, a known urethane polymerization catalyst can be added to promote the reaction.

Although the compounding quantity with respect to the biodegradable resin of the modifier for biodegradable resins which consists of a urethane compound which concerns on this invention is not specifically limited, biodegradable resin 100 weight in terms of the modification effect and mechanical properties It is preferable to mix | blend 1-80 weight part with respect to a part, and it is more preferable to mix | blend 3-55 weight part.

生分解性樹脂は水分により加水分解するため、改質剤を予め乾燥させることが望ましい。好ましくは本発明のウレタン化合物の水分量が１.０重量％以下である。 Although it can be said that the biodegradable resin composition desirably has a molecular weight retention of 80% or more after heating and kneading the additive in terms of maintaining mechanical strength, the urethane compound according to the present invention is also in this respect. Satisfied. The molecular weight retention in the present invention can be calculated by the following formula.

Since the biodegradable resin is hydrolyzed by moisture, it is desirable to dry the modifier in advance. The water content of the urethane compound of the present invention is preferably 1.0% by weight or less.

The modifier of the present invention can be used alone for a biodegradable resin, but as long as it does not impair the object of the present invention, known plasticizers, compatibilizers, and modified resins other than the present invention are necessary. An agent, a surfactant or the like may be used alone or in combination of two or more.

Hereinafter, the biodegradable resin according to the present invention will be described.
The biodegradable resin used in the present invention is, for example, at least one or two selected from hydroxycarboxylic acids, aliphatic polyhydric alcohols, aromatic polyhydric alcohols, aliphatic polycarboxylic acids, and aromatic polycarboxylic acids. It is an aliphatic polyester or aromatic polyester composed of the above, and includes a biodegradable polyester resin having biodegradability. For example, polylactic acid resin, polyethylene succinate resin, polyethylene succinate adipate resin, polybutylene succinate resin, polybutylene succinate adipate resin, polybutylene succinate carbonate resin, polyethylene carbonate resin described later, Examples thereof include polyethylene terephthalate adipate resin, polybutylene succinate terephthalate resin, polybutylene adipate terephthalate resin, polycaprolactone resin, and polyglycolic acid resin. These resins can take either form of homopolymers or copolymers (random, block, comb-shaped, etc.).

In particular, polylactic acid-based resins described later, among them, polylactic acid, polycaprolactone, polybutylene succinate, polybutylene succinate adipate, polybutylene terephthalate adipate, and polyethylene terephthalate adipate are already commercially available and are preferable because they are inexpensive and readily available. . The monomer units constituting these may be chemically modified or may be a copolymer of different monomers. Also, one or more of hydroxycarboxylic acids such as glycolic acid and 3-hydroxybutyric acid, polyvalent carboxylic acids such as succinic acid and adipic acid, polysaccharides such as cellulose acetate and ethylcellulose, and polyhydric alcohols such as ethylene glycol and diethylene glycol The copolymer of 2 or more types and the mixture of the monomer which comprises the said resin may be sufficient. Furthermore, for example, starch-based resins, chitosan-based resins, polyvinyl alcohol-based resins, and petroleum-based resins may be blended as long as the object of the present invention is not impaired.

  The molecular weight of the biodegradable resin used in the present invention is preferably a weight average molecular weight (Mw) of 6 to 1,000,000, more preferably 80 to 500,000, and most preferably 100,000 to 300,000. In general, when the weight average molecular weight (Mw) is less than 60,000, the mechanical properties of the molded product obtained by molding the resin composition is insufficient, or conversely when the molecular weight exceeds 1 million, The melt viscosity at the time of molding may become extremely high, making it difficult to handle or making it uneconomical in production.

Similarly, the molecular weight distribution (Mw / Mn) is not particularly limited as long as it can be substantially molded and exhibits sufficient mechanical properties. Is more preferable, and 2 to 5 is most preferable.

In the present invention, the polylactic acid-based resin means a polymer composition mainly composed of a polymer containing lactic acid units of 50% by weight or more, preferably 75% by weight or more. As the class, L-lactic acid, D-lactic acid, DL-lactic acid or a mixture thereof or lactide which is a cyclic dimer of lactic acid can be used. The polyethylene succinate-based resin means a polymer composition mainly composed of a polymer containing 50% by weight or more, preferably 75% by weight or more of ethylene succinate units. The same applies to the other biodegradable resins.

[Composition ratio of lactic acid units in polylactic acid resin]
As a structure of the lactic acid unit in the polylactic acid-based resin, there are L-lactic acid, D-lactic acid, and a mixture thereof, which can be appropriately selected depending on the application. When polylactic acid is used as the polylactic acid-based resin, it is preferable that D-lactic acid: L-lactic acid = 1: 99 to 30:70 when L-lactic acid is the main component. It is also possible to blend two or more types of polylactic acid having different constituent ratios of D-lactic acid and L-lactic acid. On the contrary, when D-lactic acid is the main component, L-lactic acid: D-lactic acid = 1: 99 to 30:70 is preferable, and two or more kinds of poly-polyethylenes having different constituent ratios of D-lactic acid and L-lactic acid are used. It is also possible to blend lactic acid.

As long as the object of the present invention is not impaired, the other component is an aliphatic hydroxycarboxylic acid having 2 to 10 carbon atoms other than lactic acid, an aliphatic dicarboxylic acid, an aliphatic diol or the like, or an aromatic such as terephthalic acid. It may contain a compound. Homopolymers, copolymers and mixtures thereof based on these may also be included. Moreover, you may mix other resin in the range which does not impair the physical property of this invention remarkably.

A known method is used as a method for producing the biodegradable resin used in the present invention.
For example, in the case of the polylactic acid resin preferably used in the present invention, a known method such as a method of directly dehydrating condensation polymerization of lactic acid or a method of ring-opening polymerization of lactide which is a cyclic dimer of lactic acid is used. However, the present invention is not limited to this. A publicly known method can be used as a method for producing the polylactic acid resin. For example,
(1) A method of direct dehydration polycondensation using lactic acid or a mixture of lactic acid and aliphatic hydroxycarboxylic acid as a raw material (for example, a production method shown in US Pat. No. 5,310,865)
(2) Ring-opening polymerization method in which a cyclic dimer (lactide) of lactic acid is melt-polymerized (for example, a production method disclosed in US Pat. No. 2,758,987)
(3) A ring-opening polymerization method in which a cyclic dimer of lactic acid and an aliphatic hydroxycarboxylic acid such as lactide or glycolide and ε-caprolactone is melt-polymerized in the presence of a catalyst (for example, US Pat. No. 4,057,537) Disclosed manufacturing method)
(4) A method of directly dehydrating polycondensation of a mixture of lactic acid, an aliphatic dihydric alcohol and an aliphatic dibasic acid (for example, a production method disclosed in US Pat. No. 5,428,126)
(5) A method of condensing a polymer of polylactic acid, an aliphatic dihydric alcohol and an aliphatic dibasic acid in the presence of an organic solvent (for example, a production method disclosed in European Patent Publication No. 071880 A2)
(6) In producing a polyester polymer by carrying out a dehydration polycondensation reaction in the presence of a catalyst with lactic acid, there can be mentioned a method of solid-phase polymerization in at least a part of the process. Is not particularly limited. Also, a small amount of trimethylolpropane, aliphatic polyhydric alcohol such as glycerin, aliphatic polybasic acid such as butanetetracarboxylic acid, polyhydric alcohol such as polysaccharides may be co-polymerized. Alternatively, the molecular weight may be increased by using a binder (polymer chain extender) such as a diisocyanate compound.

The biodegradable resin of the present invention includes various additives such as antioxidants, lubricants, colorants, ultraviolet absorbers, light stabilizers, pigments, inorganic fillers, modifiers and the like within a range not to impair the purpose of the present invention. A filler can be added as an additional component.

In the biodegradable resin of the present invention, a resin made from a fossil resource such as polypropylene, polyethylene or polyvinyl chloride can be mixed as an additional component within a range not impairing the object of the present invention.

When the biodegradable resin is heat-processed, it is preferably dried to suppress hydrolysis due to moisture. For example, it is preferable to perform drying for 10 hours at 80 ° C. in a nitrogen atmosphere.

Blending of the isocyanate derivative according to the present invention and an additive used in combination as necessary is performed by a uniaxial or multiaxial extruder having kneading ability. There is also a method using a master batch. The shapes obtained by using these apparatuses are usually pellets, rods, powders, etc., but are not particularly limited to these methods and shapes, and publicly known kneading techniques can be applied. .

Using the biodegradable resin composition according to the present invention as a raw material, films, sheets, molded articles, and resin emulsions excellent in the above-mentioned various performances can be produced. Known and publicly known molding methods can be applied to resin molding, film formation, sheet formation, yarn formation, and the like. It is also emulsified and applied to adhesives and coatings by blending into emulsions and diluting in solvents. The application is not particularly limited to this, and it can be suitably used as a wide range of materials such as agricultural and household goods, civil engineering and building materials, electrical appliances, packaging materials, and marine products.

The following examples illustrate the invention. However, the present invention is not limited in any way by these examples.

(Synthesis example)
[Synthesis of Compound 1]
After adding 100 parts by weight of methyl alcohol EO 10 mol adduct (component A) and 0.02 parts by weight of dibutyltin laurate to a dry 2 L flask, 30 parts by weight of isophorone diisocyanate (component B) is added over 1 hour. . The temperature is raised to 70 ° C. to 80 ° C. using the heat of reaction, and the temperature is kept. After completion of addition of component B and aging for 3 hours, a sample was taken, NCO% was measured according to JIS K1556, and it was confirmed that the unreacted isocyanate was 0.05% or less. A compound (referred to as compound 1) was obtained.

[Synthesis of Compounds 2 to 10]
Urethane compounds (Compounds 2 to 10) were obtained in the same manner as Compound 1, except that the components shown in Table 1 were used as the A component and the B component.

The properties of the urethane compounds (compounds 1 to 8) according to the present invention are as follows.

[Compounds used in comparative examples]
Ratio-1. Glycerin ester ratio-2. Methyl alcohol EO 15 mol adduct ratio-3. Dibutyl phthalate

A biodegradable resin, the urethane compound according to the present invention (compounds 1 to 10) and a comparative compound (ratio-1 to ratio-3) are blended according to the formulation shown in Table 3, and a sheet is prepared by the method described later. And used for evaluation.

生分解性樹脂
ａ．三井化学（株）製ポリ乳酸ＬＡＣＥＡ Ｈ−２８０
ｂ． 同 ＬＡＣＥＡ Ｈ−１００
ｃ．昭和高分子（株）製ポリブチレンサクシネート系ビオノーレ３００１

Biodegradable resin a. Polylactic acid LACEEA H-280 manufactured by Mitsui Chemicals, Inc.
b. LACEA H-100
c. Polybutylene succinate bionore 3001 manufactured by Showa Polymer Co., Ltd.

[Create sheet]
A sheet was prepared using a plast mill and press machine manufactured by Toyo Seiki Co., Ltd.
Kneading conditions: 180 ° C., 10 minutes Pressing conditions: 200 ° C., 15 MPa, 5 minutes The test was carried out by the following method.

[transparency]
The sheet was visually observed, and transparent was indicated by ◯, translucent was indicated by Δ, and opacity was indicated by ×.
The compatibility was also observed with transparency.

[Bleed status]
The sheet was observed after 2 weeks, x with bleeding, Δ with slight feeling, and ○ with no bleeding.

[Adhesion]
One side of the sheet was heat-sealed with aluminum foil at 120 ° C., and the peelability of the aluminum surface was observed. The case where there was adhesion was indicated by ◯, and the case where there was no adhesion was indicated by ×.

[Sheet properties]
The breaking strength and elongation of a 2 mm sheet were measured with a tensile tester. The unit is MPa for strength and% for elongation. Flexibility was evaluated based on the feeling of bending the sheet. “Good” indicates “Good”, “No flexibility” or “No strength” indicates “Poor”, and “Slight flexibility” indicates “Good”.
The physical properties of polylactic acid itself are as shown below.
Polylactic acid (a): strength about 40 MPa, elongation 0%, flexibility ×
Polylactic acid (b): strength about 55 MPa, elongation 0%, flexibility x

[Molecular weight retention]
The chromatographic column TSKgel SUPER HZM-M (manufactured by Tosoh Corporation) is attached to the chromatography SCL-10Avp (manufactured by Shimadzu Corporation), the eluent chloroform, the flow rate 0.6 ml / min, the column temperature 40 ° C., the sample concentration 0.05 wt%, the sample injection Measurement was performed under the conditions of an amount of 50 μL and a detector RI, and the weight average molecular weight of a sheet prepared in terms of polystyrene was calculated. The weight average molecular weights of the standard polystyrene used are 1090000, 706000, 355000, 190000, 96400, 37900, 19600, 10200, 5570, 2630, 870, 500. The molecular weight retention was evaluated according to the following criteria.
90% or more ... Excellent 80% or more ... Good Less than 80% ... Bad

Table 4 summarizes the evaluation results of the samples obtained in Examples 1 to 10 and Comparative Examples 1 to 3.

By blending the biodegradable resin, especially the poly (lactic acid) with the urethane compound according to the present invention, resin properties such as flexibility, adhesion, and compatibility are well balanced without significant deterioration in physical properties or aging due to bleeding. It is possible to impart sex. By widely applying these technologies, it is possible to reduce the burden on the environment and contribute to the realization of a resource recycling society.

Claims (6)

A biodegradable resin modifier comprising a urethane compound obtained by reacting an alkylene oxide adduct (component A) of a compound having a hydroxyl group with a compound having an isocyanate group (component B). A biodegradable resin composition comprising 1 to 80 parts by weight of the modifier according to claim 1 in 100 parts by weight of a biodegradable resin. The resin composition according to claim 2, wherein the biodegradable resin is a biodegradable polyester resin. The resin composition according to claim 2, wherein the biodegradable resin is a polylactic acid resin. The resin composition according to any one of claims 2 to 4, having a molecular weight retention of 80% or more. A film, a sheet, a molded product, and a resin emulsion produced using the resin composition according to any one of claims 2 to 5 as a raw material.