JP2021091846A - Degradation promoter for biodegradable resin, biodegradable resin composition and biodegradable resin molding - Google Patents

Abstract

To provide a biodegradation promoter suitable for a biodegradable resin that improves the biodegradation rate and degradation rate of a biodegradable resin such as an aliphatic polyester resin, an aliphatic-aromatic polyester resin, an aliphatic oxycarboxylic acid resin, in an arbitrarily controllable manner, and can maintain mechanical strength such as tensile breaking elongation and flexural modulus, and a biodegradable resin composition containing the biodegradation promoter.SOLUTION: A degradation promoter for biodegradable resin contains cellulose, hemicellulose and lignin. Relative to 100 mass% of the total of cellulose, hemicellulose and lignin, 10-30 mass% of lignin is contained, and the ratio of the cellulose content to the hemicellulose content is 0.5-4.0. A biodegradable resin composition contains the biodegradation promoter 2-250 pts.mass and a biodegradable resin 100 pts.mass .SELECTED DRAWING: None

Description

The present invention comprises a biodegradable accelerator capable of promoting biodegradation of a biodegradable resin, a biodegradable resin composition containing the same, and an extrusion molding or injection molding of the biodegradable resin composition. It relates to a biodegradable resin molded body.

In recent years, concerns about ecosystem and environmental pollution due to marine disposal of plastic products have become apparent. Various regulations are being enacted in various countries around the world from the viewpoint of preventing environmental pollution. For example, in Europe, regulations and legislation are being enacted that prohibit the use of disposable plastic shopping bags and cups and dishes in disposable plastic containers in the retail industry. In order to be exempt from the use prohibition measures of this law, products that can be composted even in ordinary households using biomass that exceeds the minimum required biomass content specified here (home compostable products) ) Is required. Recently, there has been a demand for marine biodegradable plastic products in which plastic products that have flowed out into the ocean decompose even in the sea.

Conventionally, as biodegradable plastics (resins), for example, polybutylene terephthalate / adipate (hereinafter abbreviated as PBAT), polylactic acid (hereinafter abbreviated as PLA), polybutylene succinate (hereinafter abbreviated as PBS). , Polybutylene succinate / adipate (hereinafter abbreviated as PBSA) and other aliphatic polyesters, polyhydroxyalkanol (hereinafter abbreviated as PHA) and the like are known. Further, PHA includes poly (3-hydroxybutyrate) (hereinafter abbreviated as PHB), poly (3-hydroxybutyrate / 3-hydroxyvalerate) (hereinafter abbreviated as PHBV), and poly (3-hydroxy). Butyrate / 3-hydroxyhexanoate) (hereinafter abbreviated as PHBH), poly (3-hydroxybutyrate / 4-hydroxybutyrate) and the like.

These resins differ not only in the biodegradation rate and decomposition rate of the resin alone, but also in the mechanical properties such as tensile elongation at break and flexural modulus. It is used by combining each resin or mixing it with other auxiliary materials and additives to improve physical properties such as mechanical strength.

Patent Document 1 also takes into consideration the final disposal treatment after the product has been used, and is a biodegradable resin that decomposes at the time of landfill and does not remain in the environment, and does not emit harmful substances such as dioxin at the time of incineration. As a molding material composed of a biomass material, an unsaturated carboxylic acid or an unsaturated carboxylic acid thereof with respect to 5 to 95% by weight of an aliphatic aromatic polyester (component A), cellulose, lignocellulose or a starch-based substance (component B) 95 to 5% by weight. A method for producing a composite resin composition having excellent molding processability and strength characteristics by heating and kneading a composition containing a derivative and an organic peroxide (C component) is disclosed. Further, Patent Document 2 describes a plant material containing cellulose in a high-molecular-weight aliphatic polyester, for example, a material consisting of the epidermis or skin layer of a plant, a seed coat material, a material for fruit skin, bagasse, milling waste, or , A resin composition and a molded product containing bagasse of sugarcane stalks and the like are disclosed.

Japanese Unexamined Patent Publication No. 2003-221423 Special Table 2004-503415

For home compostable plastic products and marine biodegradable plastic products, the biodegradation rate and decomposition rate are more severe than the conventional conditions generally considered to be biodegradable. (For example, in an environment where the temperature is low and there are few degrading bacteria), it is necessary to be faster than the biodegradable rate of conventional biodegradable resins such as PBAT, PBS, PBSA, PLA, and PHBH, and to decompose more in the same time. It is said that.

Although the mechanical strength of the resin compositions and molded products made of the resin compositions described in Patent Documents 1 and 2 described above is improved to some extent, the biodegradation rate and the decomposition rate are not paid attention to here, and the actual biodegradation rate is not paid attention to. It is unclear how much the decomposition rate was higher than that of conventional biodegradable resins. In addition, depending on the additives and auxiliary materials used, the decomposition rate deteriorated and the mechanical strength did not improve.

The present invention has been made in view of this background, and the biodegradability rate and decomposition rate of biodegradable resins such as aliphatic polyester resins, aliphatic-aromatic polyester resins, and aliphatic oxycarboxylic acid resins. A biodegradable resin suitable for biodegradable resins, which can increase and arbitrarily control, and can maintain mechanical strength such as tensile elongation at break and bending elasticity, and raw materials containing this biodegradable accelerator. It is an object of the present invention to provide a degradable resin composition and a molded product thereof.

As a result of diligent studies to solve the above problems, the present inventors have focused on three components, cellulose, hemicellulose and lignin, and these components contribute to the promotion of decomposition of the biodegradable resin. By adjusting these blending ratios, the biodegradable rate and decomposition rate of the biodegradable resin will be higher than the original biodegradable rate and decomposition rate of the biodegradable resin. The present invention has been made by finding that a molded product of the biodegradable resin composition can exhibit certain mechanical properties.
That is, the gist of the present invention lies in the following [1] to [8].

[1] A decomposition accelerator for a biodegradable resin containing cellulose, hemicellulose and lignin, which contains 10% by mass or more and 30% by mass or less of lignin with respect to 100% by mass of the total of cellulose, hemicellulose and lignin, and contains hemicellulose. A decomposition accelerator for biodegradable resins in which the ratio of the content of cellulose to the amount is 0.5 to 4.0.

[2] The decomposition accelerator for a biodegradable resin according to [1], which is a powder or granular material and has a particle size of 15 μm or less.

[3] A biodegradable resin composition containing 2 parts by mass or more and 250 parts by mass or less of the decomposition accelerator for biodegradable resin and 100 parts by mass of the biodegradable resin according to [1] or [2].

[4] The biodegradable resin is one or more selected from the group consisting of an aliphatic polyester resin (A), an aliphatic-aromatic polyester resin (B) and an aliphatic oxycarboxylic acid resin (C). The biodegradable resin composition according to [3].

[5] The biodegradable resin composition according to [4], wherein the aliphatic polyester resin (A) contains a repeating unit derived from an aliphatic diol and a repeating unit derived from an aliphatic dicarboxylic acid as main constituent units. Stuff.

[6] The aliphatic-aromatic polyester resin (B) has a repeating unit derived from an aliphatic diol, a repeating unit derived from an aliphatic dicarboxylic acid, and a repeating unit derived from an aromatic dicarboxylic acid as main constituent units. The biodegradable resin composition according to [4], which comprises.

[7] A biodegradable resin molded product which is an extrusion molded product or an injection molded product of the biodegradable resin composition according to any one of [3] to [6].

[8] The biodegradable resin molded product according to [7], wherein the extruded molded product or the injection molded product has a thin portion having a thickness of 50 μm or more and 4 mm or less.

According to the decomposition accelerator for biodegradable resins of the present invention, while maintaining mechanical strength such as tensile elongation at break and bending elasticity, aliphatic polyester resins, aliphatic-aromatic polyester resins, and aliphatic oxy The biodegradable rate and decomposition rate of a biodegradable resin such as a carboxylic acid-based resin can be made higher than the original biodegradable rate and decomposition rate of the biodegradable resin.
According to the biodegradable resin composition of the present invention containing such a decomposition accelerator for biodegradable resin of the present invention, a biodegradable resin molded body having excellent biodegradability and excellent mechanical properties is provided. To.

Embodiments of the present invention will be described in detail below.
The present invention is not limited to the following description, and can be arbitrarily modified and carried out without departing from the gist of the present invention. In addition, in this specification, when a numerical value or a physical property value is put before and after using "~", it is used as including the value before and after that.

[Decomposition accelerator for biodegradable resin]
The decomposition accelerator for biodegradable resins of the present invention (hereinafter, may be referred to as "biodegradation accelerator of the present invention") contains cellulose, hemicellulose and lignin as essential components, and is cellulose and hemicellulose. It is characterized in that lignin is contained in an amount of 10% by mass or more and 30% by mass or less based on 100% by mass of the total amount of lignin, and the ratio of the content of hemicellulose to the content of cellulose is 0.5 to 4.0.

The biodegradation accelerator of the present invention can be obtained by using a raw material containing the above three components as a raw material and adjusting the concentration and ratio thereof. As a raw material, leaves, bark, chips, etc. generated during sawing can also be used. Preferred woods are broad-leaved and / or deciduous trees, and specific examples thereof include zelkova, beech, oak, poplar, platanus orientalis, vertebrae, apples, chestnuts, and cherry blossoms. It is also possible to use the residue of squeezed seeds and fruits and the removed shells. Specific examples include pistachios, walnuts, chestnuts, peanuts, defatted rice bran and barley rice husks, abra palm, bagasse, cotton, soybeans, corn nuts and stems (corn cobs). Other examples include bamboo, switchgrass and hemp.

The biodegradation accelerator of the present invention is preferably used as a powder or granular material by pulverizing the above raw materials. At that time, it is preferable to set the particle size to a certain level. When two or more kinds of raw materials are used, the raw materials may be crushed separately or a mixture in which the raw materials are mixed in advance may be crushed. From the viewpoint that the ratio and ratio of the above-mentioned cellulose, hemicellulose and lignin can be easily controlled within the above range, it is preferable to pulverize each raw material in advance and mix them.

The raw material can be crushed using, for example, a crusher such as a stone mill, a cutter mill, a jet mill, or a crush mill.

The particle size after pulverization is usually 500 μm or less, preferably 500 μm or less, from the viewpoint that when used with a biodegradable resin, it is more easily mixed with the biodegradable resin and is more effective as a biodegradable accelerator. It is 300 μm or less, more preferably 100 μm or less. Further, in order to obtain good mechanical properties and appearance as well as a biodegradation promoting effect, the particle size is preferably 15 μm or less, particularly preferably 10 μm or less. This particle size refers to the average particle size measured by the method described in the section of Examples described later.
Further, when the biodegradable resin composition containing the biodegradable resin composition of the present invention described later is molded and used, it has a thin portion having a thickness (thinnest portion; the same applies hereinafter) of 4 mm or less, for example, 50 μm or more and 4 mm or less. In the case of a biodegradable resin molded product, the particle size of the biodegradable accelerator is preferably 15 μm or less, for example, 5 to 15 μm. Further, in the case of a biodegradable resin molded product having an ultrathin portion having a thickness of less than 50 μm, for example, 10 μm or more and less than 50 μm, the particle size of the biodegradable accelerator is preferably 10 μm or less, for example, 3 to 10 μm.

Here, various known methods such as a sieving method, a laser diffraction method, and a microscopic method can be used for measuring the particle size of the biodegradation accelerator. Further, the biodegradation accelerator can be adjusted to a desired particle size by selecting the biodegradation accelerator using a mesh sieve having a particle size of the particle size. Therefore, for example, by sorting using a mesh sieve having a mesh size of 15 μm, a biodegradation accelerator having a particle size of 15 μm or less can be obtained under the sieve. The biodegradation accelerator of the present invention can be obtained by sorting the powder obtained by pulverizing each raw material in this way and blending the powder having a predetermined particle size in a specific ratio as needed. The powder preferably used in this case is not particularly limited as long as it is the powder of the above-mentioned raw materials, but poplar powder, hemp sieve powder, peanut shell powder, pistachio shell powder, sunflower seed powder, defatted rice bran and the like are used. Can be mentioned.

When mixing the biodegradation accelerator of the present invention with a biodegradable resin, it is preferable to dry it in advance. The reason is that moisture in the atmosphere (air) in the storage atmosphere is adsorbed during storage, and it becomes difficult for the moisture to mix with the biodegradable resin.

The biodegradation accelerator of the present invention has a lignin content of 10% by mass or more and 30% by mass or less with respect to a total of 100% by mass of cellulose, hemicellulose and lignin. If the content of lignin is less than 10% by mass, the effect of improving biodegradability is not sufficient, and if the content of lignin is more than 30% by mass, the effect of improving biodegradability is not sufficient. Further, since the contents of cellulose and hemicellulose are relatively low and the effect of containing these may be impaired, the content of lignin with respect to 100% by mass of the total of cellulose, hemicellulose and lignin is preferably 13. It is by mass% or more and 28% by mass or less, and more preferably 15% by mass or more and 27% by mass or less.

Further, the biodegradation accelerator of the present invention has a ratio of the cellulose content to the hemicellulose content (hereinafter, may be referred to as “cellulose / hemicellulose ratio”) of 0.5 to 4.0. If the cellulose / hemicellulose ratio is less than 0.5, the biodegradability improving effect tends to decrease, and at the same time, the rigidity of the resin composition decreases, and even if it is larger than 4.0, the biodegradability improving effect tends to decrease. descend. The cellulose / hemicellulose ratio is preferably 0.8 or more and 3.5 or less, and particularly preferably 1.0 or more and 2.5 or less.

The total amount of cellulose, hemicellulose and lignin in the biodegradation accelerator of the present invention is 70% by mass or more, particularly 80% by mass or more, particularly preferably 90% by mass or more in 100% by mass of the biodegradation accelerator. It is preferable that it is contained as such.
When the biodegradable accelerator contains water, it is preferably dried to reduce the water content to 5% by mass or less. If the water content is larger than 5% by mass, the biodegradable resin may be hydrolyzed when mixed with the biodegradable resin, the molecular weight may be lowered, and the mechanical strength may not be sufficient. The water content can be measured by using a heating weight loss method, a Karl Fischer method, or the like.

For drying, for example, a batch type dryer such as a hot air dryer, a vacuum dryer, or an inert oven, or a continuous type dryer such as a vibrating fluidized bed dryer, an air flow dryer, or a cylindrical dryer can be used. The drying temperature is usually in the range of 40 ° C to 200 ° C. If the temperature is too low, the drying efficiency will decrease, and if the temperature is too high, problems such as poor appearance and odor due to discoloration may occur.

The contents of cellulose, hemicellulose and lignin in the biodegradation accelerator of the present invention can be measured and calculated by the methods described in Examples described later.
Further, in the case of a biodegradation accelerator using two or more kinds of raw materials, the content of cellulose, hemicellulose and lignin is the ratio of the contents of cellulose, hemicellulose and lignin of each raw material according to the blending ratio of the raw materials. Can be calculated as the sum of the products multiplied by.

[Biodegradable resin composition]
The biodegradable resin composition of the present invention contains 2 parts by mass or more and 250 parts by mass or less of the decomposition accelerator for biodegradable resin of the present invention and 100 parts by mass of the biodegradable resin. In the biodegradable resin composition of the present invention, when the content of the biodegradable accelerator of the present invention is less than 2 parts by mass with respect to 100 parts by mass of the biodegradable resin, the biodegradable resin composition of the present invention is contained. The effect of improving degradability cannot be sufficiently obtained. On the other hand, if the content of the biodegradation accelerator of the present invention exceeds 250 parts by mass, the mechanical properties of the obtained molded product are impaired.
The biodegradable resin composition of the present invention preferably contains 10 parts by mass or more and 100 parts by mass or less of the biodegradable accelerator of the present invention with respect to 100 parts by mass of the biodegradable resin, and contains 15 parts by mass or more and 80 parts by mass or less. Is more preferable.

The biodegradable resin contained in the biodegradable resin composition of the present invention may be any biodegradable resin, and is not particularly limited, but is an aliphatic polyester resin (A) or an aliphatic-aromatic resin. Examples thereof include polyester-based resin (B) and aliphatic oxycarboxylic acid-based resin (C).
Two or more of the aliphatic polyester resin (A), the aliphatic-aromatic polyester resin (B), and the aliphatic oxycarboxylic acid resin (C) may be mixed and used.

Each biodegradable resin will be described below.

The aliphatic polyester resin (A), the aliphatic-aromatic polyester resin (B), and the aliphatic oxycarboxylic acid resin (C) are polymers having a repeating unit, but each repeating unit. Is also referred to as a compound unit for the compound from which each repeating unit is derived. For example, a repeating unit derived from an aliphatic diol is an "aliphatic diol unit", a repeating unit derived from an aliphatic dicarboxylic acid is a "aliphatic dicarboxylic acid unit", and a repeating unit derived from an aromatic dicarboxylic acid is a "aromatic dicarboxylic acid". Also called "acid unit".
The "main constituent unit" in the aliphatic polyester resin (A), the aliphatic-aromatic polyester resin (B), and the aliphatic oxycarboxylic acid resin (C) is usually the constituent unit. It is a structural unit contained in the polyester resin in an amount of 80% by mass or more, and may not contain any structural unit other than the main structural unit.

<Alphatic polyester resin (A)>
As the aliphatic polyester resin (A) used in the present invention, an aliphatic polyester resin containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit as main constituent units is preferable.

In the aliphatic polyester resin (A) used in the present invention, the ratio of the succinic acid unit to the total dicarboxylic acid unit is preferably 5 mol% or more and 100 mol% or less. The aliphatic polyester resin (A) may be a mixture of aliphatic polyester resins having different amounts of succinic acid units, and does not contain, for example, an aliphatic dicarboxylic acid unit other than succinic acid (aliphatic dicarboxylic acid unit). The amount of succinic acid unit in the aliphatic polyester resin (A) by blending the aliphatic polyester resin (containing only the succinic acid unit as) and the aliphatic polyester resin containing an aliphatic dicarboxylic acid unit other than succinic acid. Can be adjusted and used within the above-mentioned preferable range.

More specifically, the aliphatic polyester resin (A) is a polyester resin containing an aliphatic diol unit represented by the following formula (1) and an aliphatic dicarboxylic acid unit represented by the following formula (2). Is.
-O-R ^1- O- (1)
-OC-R ^2- CO- (2)

In formula (1), R ¹ represents a divalent aliphatic hydrocarbon group. Further, in the above formula (2), R ² represents a divalent aliphatic hydrocarbon group. The aliphatic diol unit and the aliphatic dicarboxylic acid unit represented by the above formulas (1) and (2) may be derived from a compound derived from petroleum or a compound derived from a plant material. Although not, it is desirable that it is derived from a compound derived from a plant material.

When the aliphatic polyester resin (A) is a copolymer, even if the aliphatic polyester resin (A) contains two or more kinds of aliphatic diol units represented by the formula (1). Often, the aliphatic polyester resin (A) may contain two or more kinds of aliphatic dicarboxylic acid units represented by the formula (2).

As described above, the aliphatic dicarboxylic acid unit represented by the formula (2) preferably contains 5 mol% or more and 100 mol% or less of the succinic acid unit with respect to the total dicarboxylic acid unit. By setting the amount of the succinic acid constituent unit in the aliphatic polyester resin (A) within the above-mentioned predetermined range, it is possible to obtain a biodegradable resin composition having improved moldability and excellent heat resistance and decomposability. It becomes. For the same reason, the amount of succinic acid unit in the aliphatic polyester resin (A) is preferably 10 mol% or more, more preferably 50 mol% or more, still more preferably 64 mol% or more, based on the total dicarboxylic acid unit. , Particularly preferably 68 mol% or more.
Hereinafter, the ratio of the succinic acid unit to the total dicarboxylic acid unit in the aliphatic polyester resin (A) may be referred to as "succinic acid unit amount".

Further, the aliphatic dicarboxylic acid unit represented by the formula (2) contains 5 mol% or more and 50 mol% or less of one or more kinds of aliphatic dicarboxylic acid units in addition to succinic acid with respect to the total dicarboxylic acid units. Is more preferable. By copolymerizing an aliphatic dicarboxylic acid unit other than succinic acid within the above predetermined range, the crystallinity of the aliphatic polyester resin (A) can be lowered, and the biodegradation rate can be increased. For the same reason, the amount of the aliphatic dicarboxylic acid unit other than succinic acid in the aliphatic polyester resin (A) is preferably 10 mol% or more and 45 mol% or less, more preferably 45 mol% or less, based on the total dicarboxylic acid unit. It is 15 mol% or more and 40 mol% or less.

The aliphatic diol giving the diol unit represented by the formula (1) is not particularly limited, but from the viewpoint of moldability and mechanical strength, an aliphatic diol having 2 or more and 10 or less carbon atoms is preferable, and 4 or more carbon atoms are preferable. Aliphatic diols of 6 or less are particularly preferred. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like can be mentioned, and 1,4-butanediol is particularly preferable. It should be noted that two or more kinds of the above aliphatic diols can be used.

The aliphatic dicarboxylic acid component that gives the aliphatic dicarboxylic acid unit represented by the formula (2) is not particularly limited, but an aliphatic dicarboxylic acid having 2 or more and 40 or less carbon atoms and a derivative such as an alkyl ester thereof are preferable. Derivatives such as an aliphatic dicarboxylic acid having 4 or more and 10 or less carbon atoms and an alkyl ester thereof are particularly preferable. Derivatives of aliphatic dicarboxylic acids having 4 or more and 10 or less carbon atoms other than succinic acid and alkyl esters thereof include, for example, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid and the like and alkyl esters thereof. Examples thereof include adipic acid and sebacic acid, and adipic acid is particularly preferable. It should be noted that two or more kinds of the above aliphatic dicarboxylic acid components can be used, and in this case, a combination of succinic acid and adipic acid is preferable.

The aliphatic polyester resin (A) may have a repeating unit (aliphatic oxycarboxylic acid unit) derived from the aliphatic oxycarboxylic acid. Specific examples of the aliphatic oxycarboxylic acid component giving the aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, and 2-hydroxy. Examples thereof include -3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid and the like, or derivatives such as lower alkyl esters or intramolecular esters thereof. When optical isomers are present in these, any of D-form, L-form, and racemic form may be used, and the form may be any of solid, liquid, and aqueous solution. Of these, particularly preferred are lactic acid or glycolic acid or derivatives thereof. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more kinds.

When the aliphatic polyester resin (A) contains these aliphatic oxycarboxylic acid units, the content thereof is 100 mol% of all the constituent units constituting the aliphatic polyester resin (A) from the viewpoint of moldability. It is preferably 20 mol% or less, more preferably 10 mol% or less, further preferably 5 mol% or less, and most preferably 0 mol% (not included).

The aliphatic polyester resin (A) is a trifunctional or higher aliphatic polyhydric alcohol, a trifunctional or higher functional aliphatic polyvalent carboxylic acid or an acid anhydride thereof, or a trifunctional or higher functional aliphatic polyvalent oxycarboxylic acid component. The melt viscosity may be increased by copolymerizing the above.

Specific examples of the trifunctional aliphatic polyhydric alcohol include trimethylolpropane and glycerin, and specific examples of the tetrafunctional aliphatic polyhydric alcohol include pentaerythritol and the like. These can be used alone or in combination of two or more.
Specific examples of the trifunctional aliphatic polyvalent carboxylic acid or its acid anhydride include propanetricarboxylic acid or its acid anhydride, and specific examples of the tetrafunctional polyvalent carboxylic acid or its acid anhydride include. Cyclopentanetetracarboxylic acid or an acid anhydride thereof and the like can be mentioned. These can be used alone or in combination of two or more.

The trifunctional aliphatic oxycarboxylic acid has (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) having one carboxyl group and two hydroxyl groups. It is divided into types, and any type can be used, but from the viewpoint of moldability, mechanical strength, and appearance of the molded product, (i) two carboxyl groups such as malic acid and one hydroxyl group are contained in the same molecule. The type having is preferable, and more specifically, malic acid is preferably used. The tetrafunctional aliphatic oxycarboxylic acid component is (i) a type in which three carboxyl groups and one hydroxyl group are shared in the same molecule, and (ii) two carboxyl groups and two hydroxyl groups. It is divided into a type that shares a group in the same molecule and a type that shares three hydroxyl groups and one carboxyl group in the same molecule (iii). Any type can be used, but the carboxyl group can be used. Those having a plurality of them are preferable, and more specific examples thereof include citric acid and tartrate acid. These can be used alone or in combination of two or more.

When the aliphatic polyester resin (A) contains a structural unit derived from such a trifunctional or higher functional component, the content thereof is 100 mol% with all the structural units constituting the aliphatic polyester resin (A) as 100 mol%. The lower limit is usually 0 mol% or more, preferably 0.01 mol% or more, and the upper limit is usually 5 mol% or less, preferably 2.5 mol% or less.

As the method for producing the aliphatic polyester resin (A) according to the present invention, a known method for producing polyester can be adopted. Further, the polycondensation reaction at this time is not particularly limited as appropriate conditions that have been conventionally adopted can be set. Usually, a method of further increasing the degree of polymerization by performing a reduced pressure operation after advancing the esterification reaction is adopted.

When the diol component forming a diol unit and the dicarboxylic acid component forming a dicarboxylic acid unit are reacted during the production of the aliphatic polyester resin (A), the object of the produced aliphatic polyester resin (A) is The amount of the diol component and the dicarboxylic acid component used is set so as to have the composition of. Normally, the diol component and the dicarboxylic acid component react in substantially equal molar amounts, but since the diol component is distilled off during the esterification reaction, it is usually 1 to 20 mol% more than the dicarboxylic acid component. Used.

When the aliphatic polyester resin (A) contains a component (arbitrary component) other than essential components such as an aliphatic oxycarboxylic acid unit and a polyfunctional component unit, the aliphatic oxycarboxylic acid unit and the polyfunctional component unit are also included. The corresponding compounds (monomers and oligomers) are subjected to the reaction so as to obtain the desired composition. At this time, there is no limitation on the timing and method of introducing the above-mentioned arbitrary component into the reaction system, and it is arbitrary as long as the aliphatic polyester resin (A) suitable for the present invention can be produced.

For example, the timing and method for introducing the aliphatic oxycarboxylic acid into the reaction system are not particularly limited as long as it is before the polycondensation reaction between the diol component and the dicarboxylic acid component. Examples thereof include a method of mixing in a dissolved state, and (2) a method of introducing the catalyst into the reaction system at the time of charging the raw materials and mixing at the same time.

The compound forming the polyfunctional component unit may be introduced at the same time as other monomers or oligomers in the initial stage of polymerization, or may be charged after the transesterification reaction and before the start of reduced pressure, but other monomers. It is preferable to prepare at the same time as the oligomer or oligomer from the viewpoint of simplifying the process.

The aliphatic polyester resin (A) is usually produced in the presence of a catalyst. As the catalyst, a catalyst that can be used in the production of a known polyester-based resin can be arbitrarily selected as long as the effects of the present invention are not significantly impaired. For example, metal compounds such as germanium, titanium, zirconium, hafnium, antimony, tin, magnesium, calcium and zinc are suitable. Of these, germanium compounds and titanium compounds are preferable.

Examples of the germanium compound that can be used as a catalyst include an organic germanium compound such as tetraalkoxygermanium, an inorganic germanium compound such as germanium oxide and germanium chloride, and the like. Among them, germanium oxide, tetraethoxygermanium, tetrabutoxygermanium and the like are preferable, and germanium oxide is particularly preferable, from the viewpoint of price and availability.

Examples of the titanium compound that can be used as a catalyst include organic titanium compounds such as tetraalkoxytitanium such as tetrapropyl titanate, tetrabutyl titanate, and tetraphenyl titanate. Of these, tetrapropyl titanate and tetrabutyl titanate are preferable because of their price and availability.

Further, as long as the object of the present invention is not impaired, the combined use of other catalysts is not hindered. One type of catalyst may be used alone, or two or more types may be used in any combination and ratio.

The amount of the catalyst used is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.0005% by mass or more, more preferably 0.001% by mass or more, and usually 3 with respect to the amount of the monomer used. It is mass% or less, preferably 1.5 mass% or less. If it is below the lower limit of this range, the effect of the catalyst may not appear, and if it exceeds the upper limit, the manufacturing cost may increase, the obtained polymer may be significantly colored, or the hydrolysis resistance may be lowered.

The time for introducing the catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be introduced at the time of charging the raw materials or at the start of depressurization. When introducing an aliphatic oxycarboxylic acid unit, it is introduced at the same time as a monomer or oligomer that forms an aliphatic oxycarboxylic acid unit such as lactic acid or glycolic acid at the time of raw material preparation, or the catalyst is dissolved in an aqueous aliphatic oxycarboxylic acid solution. In particular, the method of dissolving the catalyst in an aqueous aliphatic oxycarboxylic acid solution and introducing it is preferable in terms of increasing the polymerization rate.

The reaction conditions such as temperature, polymerization time, and pressure when producing the aliphatic polyester resin (A) are arbitrary as long as the effects of the present invention are not significantly impaired, but the transesterification reaction between the dicarboxylic acid component and the diol component. The lower limit of the reaction temperature of the and / or transesterification reaction is usually 150 ° C. or higher, preferably 180 ° C. or higher, and the upper limit is usually 260 ° C. or lower, preferably 250 ° C. or lower. The reaction atmosphere is usually under an inert atmosphere such as nitrogen or argon. Further, the reaction pressure is usually 10 kPa at normal pressure, but normal pressure is particularly preferable. The lower limit of the reaction time is usually 1 hour or more, and the upper limit is usually 10 hours or less, preferably 6 hours or less, and more preferably 4 hours or less. If the reaction temperature is too high, overproduction of unsaturated bonds may occur, gelation due to unsaturated bonds may occur, and it may be difficult to control the polymerization.

Further, in the polycondensation reaction after the transesterification reaction and / or the transesterification reaction between the dicarboxylic acid component and the diol component, the lower limit of the pressure is usually 0.01 × 10 ³ Pa or more, preferably 0.03 × 10 ³ Pa or more. It is desirable that the upper limit is usually 1.4 × 10 ³ Pa or less, preferably 0.4 × 10 ^{3 Pa or less.} The reaction temperature at this time has a lower limit of usually 150 ° C. or higher, preferably 180 ° C. or higher, and an upper limit of usually 260 ° C. or lower, preferably 250 ° C. or lower. Further, the lower limit of the reaction time is usually 2 hours or more, and the upper limit is usually 15 hours or less, preferably 10 hours or less. If the reaction temperature is too high, overproduction of unsaturated bonds may cause gelation due to unsaturated bonds, making it difficult to control polymerization.

When producing the aliphatic polyester resin (A), a chain extender such as a carbonate compound or a diisocyanate compound can also be used. In this case, the amount of the chain extender is usually 10 as the ratio of carbonate bonds and urethane bonds in the aliphatic polyester resin (A) when all the constituent units constituting the aliphatic polyester resin are 100 mol%. It is mol% or less, preferably 5 mol% or less, and more preferably 3 mol% or less. However, the presence of urethane bonds or carbonate bonds in the aliphatic polyester resin (A) may inhibit biodegradability. Therefore, in the present invention, all the configurations constituting the aliphatic polyester resin (A) are formed. The carbonate bond is less than 1 mol%, preferably 0.5 mol% or less, more preferably 0.1 mol% or less, and the urethane bond is 0.55 mol% or less, preferably 0.3 mol% or less, based on the unit. Hereinafter, it is more preferably 0.12 mol% or less, still more preferably 0.05 mol% or less. When converted to 100 parts by mass of the aliphatic polyester resin (A), this amount is 0.9 parts by mass or less, preferably 0.5 parts by mass or less, more preferably 0.2 parts by mass or less, and further preferably 0. . 1 part by mass or less. In particular, if the urethane bond amount exceeds the above upper limit value, smoke or odor from the molten film from the die outlet may become a problem due to decomposition of the urethane bond in the film forming process or the like, and in the molten film. The film may break due to foaming and stable molding may not be possible.
The amount of carbonate bond and the amount of urethane bond in the aliphatic polyester resin (A) can be calculated and obtained from the NMR measurement results such as ¹ H-NMR and ^{13 C-NMR.}

Specific examples of the carbonate compound as the chain extender include diphenyl carbonate, ditril carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and ethylene carbonate. , Diamil carbonate, dicyclohexyl carbonate and the like. In addition, carbonate compounds composed of the same or different types of hydroxy compounds derived from hydroxy compounds such as phenols and alcohols can also be used.

Specific examples of the diisocyanate compound include 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, and xylylene diisocyanate. Xylylene diisocyanate hydride, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, 2,4,6-triisopropylphenyldiisocyanate, 4,4'-diphenylmethane diisocyanate, trizine diisocyanate, etc. Examples of known diisocyanates and the like.

Moreover, dioxazoline, silicic acid ester and the like may be used as other chain extenders.
Specific examples of the silicic acid ester include tetramethoxysilane, dimethoxydiphenylsilane, dimethoxydimethylsilane, and diphenyldihydroxysilane.

High molecular weight polyester resins using these chain extenders (coupling agents) can also be produced by using conventional techniques. After the completion of polycondensation, the chain extender is added to the reaction system in a uniform molten state without a solvent, and is reacted with the polyester obtained by polycondensation.

More specifically, a terminal group obtained by catalytically reacting a diol component and a dicarboxylic acid component has a substantially hydroxyl group and has a weight average molecular weight (Mw) of 20,000 or more, preferably 40,000. By reacting the above polyester with the chain extender, a polyester resin having a higher molecular weight can be obtained. Prepolymers with a weight average molecular weight of 20,000 or more are not affected by the remaining catalyst even under harsh conditions such as a molten state by using a small amount of chain extender, so that they are high without forming a gel during the reaction. A polyester resin having a molecular weight can be produced. Here, the weight average molecular weight (Mw) of the polyester resin is obtained as a conversion value using monodisperse polystyrene from a value measured by gel permeation chromatography (GPC) at a measurement temperature of 40 ° C. using chloroform as a solvent.

Therefore, for example, when the polyester resin is further increased in molecular weight by using the above diisocyanate compound as a chain extender, a prepolymer having a weight average molecular weight of 20,000 or more, preferably 40,000 or more is used. preferable. If the weight average molecular weight is less than 20,000, the amount of the diisocyanate compound used for increasing the molecular weight may increase and the heat resistance may decrease. Using such a prepolymer, a polyester resin having a urethane bond having a linear structure linked via a urethane bond derived from a diisocyanate compound is produced.

The pressure at the time of chain extension is usually 0.01 MPa or more and 1 MPa or less, preferably 0.05 MPa or more and 0.5 MPa or less, more preferably 0.07 MPa or more and 0.3 MPa or less, but normal pressure is most preferable.

The lower limit of the reaction temperature during chain extension is usually 100 ° C. or higher, preferably 150 ° C. or higher, more preferably 190 ° C. or higher, most preferably 200 ° C. or higher, and the upper limit is usually 250 ° C. or lower, preferably 240 ° C. or lower. More preferably, it is 230 ° C. or lower. If the reaction temperature is too low, the viscosity is high and uniform reaction is difficult, and high stirring power tends to be required. If the reaction temperature is too high, gelation and decomposition of the polyester resin tend to occur at the same time.

The lower limit of the chain extension time is usually 0.1 minutes or more, preferably 1 minute or more, more preferably 5 minutes or more, and the upper limit is usually 5 hours or less, preferably 1 hour or less, more preferably 30 minutes or less. Most preferably 15 minutes or less. If the chain extension time is too short, the effect of adding the chain extender tends not to be exhibited, and if it is too long, the polyester resin tends to gel or decompose.

The molecular weight of the aliphatic polyester resin (A) used in the present invention can be measured by gel permeation chromatography (GPC), and the weight average molecular weight (Mw) using monodisperse polystyrene as a standard substance can be determined. It is usually 10,000 or more and 1,000,000 or less, but is preferably 20,000 or more and 500,000 or less, more preferably 50,000 or more and 400,000 or less because it is advantageous in terms of moldability and mechanical strength. is there.

The melt flow rate (MFR) of the aliphatic polyester resin (A) is a value measured at 190 ° C. and a load of 2.16 kg based on JIS K7210 (1999), and is usually 0.1 g / 10 minutes or more and 100 g / 10. Although it is less than a minute, from the viewpoint of moldability and mechanical strength, it is preferably 50 g / 10 minutes or less, and particularly preferably 40 g / 10 minutes or less. The MFR of the aliphatic polyester resin (A) can be adjusted by the molecular weight.

The melting point of the aliphatic polyester resin (A) is preferably 70 ° C. or higher, more preferably 75 ° C. or higher, preferably 170 ° C. or lower, more preferably 150 ° C. or lower, and particularly preferably lower than 130 ° C. .. When there are a plurality of melting points, it is preferable that at least one melting point is within the above range.
The elastic modulus of the aliphatic polyester resin (A) is preferably 180 to 1000 MPa.
When the melting point is out of the above range, the moldability is inferior, and when the elastic modulus is less than 180 MPa, a problem is likely to occur in the moldability, while when the elastic modulus exceeds 1000 MPa, the impact resistance tends to be deteriorated.

The method for adjusting the melting point and elastic modulus of the aliphatic polyester resin (A) is not particularly limited, but for example, the type of copolymerization component of the aliphatic dicarboxylic acid component other than succinic acid can be selected, or each of them can be used together. It can be adjusted by adjusting the polymerization ratio or by combining them.

In the present invention, the aliphatic polyester resin (A) is not limited to one type, and two or more types of aliphatic polyester resins (A) having different types of constituent units, constituent unit ratios, manufacturing methods, physical characteristics, etc. are blended and used. be able to.

<Aliphatic-aromatic polyester resin (B)>
As the aliphatic-aromatic polyester resin (B), at least a part of the repeating unit of the above-mentioned aliphatic polyester resin (A) is replaced with an aromatic compound unit, preferably the above-mentioned aliphatic compound. A polyester containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit as main constituent units, in which a part of the aliphatic dicarboxylic acid unit of the polyester resin (A) is replaced with an aromatic dicarboxylic acid unit. A system resin is exemplified.

Examples of the aromatic compound unit include an aromatic diol unit having an aromatic hydrocarbon group which may have a substituent and an aromatic dicarboxylic acid having an aromatic hydrocarbon group which may have a substituent. Examples thereof include an aromatic dicarboxylic acid unit having an aromatic heterocyclic group which may have a substituent, an aromatic oxycarboxylic acid unit having an aromatic hydrocarbon group which may have a substituent, and the like. .. The aromatic hydrocarbon group and the aromatic heterocyclic group may be a single ring, or may be one in which a plurality of rings are bonded or condensed with each other. Specific examples of the aromatic hydrocarbon group include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, dinaphthylene group, diphenylene group and the like. Specific examples of the aromatic heterocyclic group include a 2,5-furandyl group.

Specific examples of the aromatic dicarboxylic acid component that gives an aromatic dicarboxylic acid unit include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and 2,5-furandicarboxylic acid. Of these, terephthalic acid is preferable.

The aromatic dicarboxylic acid component may be a derivative of an aromatic dicarboxylic acid compound. For example, the derivative of the aromatic dicarboxylic acid component exemplified above is preferable, and among them, a lower alkyl ester having 1 or more and 4 or less carbon atoms, an acid anhydride and the like can be mentioned. Specific examples of the derivative of the aromatic dicarboxylic acid compound include lower alkyl esters such as methyl ester, ethyl ester, propyl ester and butyl ester of the above-exemplified aromatic dicarboxylic acid component; and the above-exemplified aromatic dicarboxylic acid such as succinic anhydride. Cyclic acid anhydride as an acid component; and the like. Of these, dimethyl terephthalate is preferable.

Specific examples of the aromatic diol component that gives the aromatic diol unit include xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, and 2,2-bis (. Examples thereof include 4'-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, and bis (4-β-hydroxyethoxyphenyl) sulfonic acid. The aromatic diol component may be a derivative of an aromatic diol compound. Further, it may be a compound having a structure in which a plurality of aliphatic diol compounds and / or aromatic diol compounds are dehydrated and condensed with each other.

Specific examples of the aromatic oxycarboxylic acid component that gives the aromatic oxycarboxylic acid unit include p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid. The aromatic oxycarboxylic acid component may be a derivative of an aromatic oxycarboxylic acid compound. Further, it may be a compound (oligomer) having a structure in which a plurality of aliphatic oxycarboxylic acid compounds and / or aromatic oxycarboxylic acid compounds are dehydrated and condensed with each other. That is, an oligomer may be used as a raw material.

When an optical isomer is present in the aromatic compound component that gives these aromatic compound units, any of the D-form, the L-form, and the racemic form may be used. Further, the aromatic compound component is not limited to the above example as long as an aromatic compound unit can be given. Further, one type of aromatic compound component may be used alone, or two or more types may be used in any combination and in a ratio.

As the aliphatic-aromatic polyester resin (B), it is preferable to use an aromatic dicarboxylic acid component as a component that gives an aromatic compound unit, and the content of the aromatic dicarboxylic acid unit in this case is the aliphatic dicarboxylic acid. Based on the total amount of the unit and the aromatic dicarboxylic acid unit (100 mol%), it is preferably 10 mol% or more and 80 mol% or less. Further, it is preferable to use terephthalic acid or 2,5-furandicarboxylic acid as the aromatic dicarboxylic acid component, and in that case, the aliphatic-aromatic polyester resin (B) is polybutylene terephthalate adipate and / or polybutylene. It is preferably a terephthalate succinate resin. Further, as the aliphatic-aromatic polyester resin (B), a polybutylene-2,5-flange carboxylate resin is also preferable.

As the aliphatic-aromatic polyester resin (B), the above-mentioned aliphatic polyester resin (A) can be similarly produced by using at least an aromatic compound component as a raw material.

The molecular weight of the aliphatic-aromatic polyester resin (B) used in the present invention can be measured by gel permeation chromatography (GPC), and the weight average molecular weight (Mw) using monodisperse polystyrene as a standard material. ) Is usually 10,000 or more and 1,000,000 or less, but is preferably 30,000 or more and 800,000 or less, more preferably 50,000 or more and 600, because it is advantageous in terms of moldability and mechanical strength. It is 000 or less.

The melt flow rate (MFR) of the aliphatic-aromatic polyester resin (B) is a value measured at 190 ° C. and a load of 2.16 kg based on JIS K7210 (1999), and is usually 0.1 g / 10 minutes or more. Although it is 100 g / 10 minutes or less, it is preferably 50 g / 10 minutes or less, and particularly preferably 30 g / 10 minutes or less, from the viewpoint of moldability and mechanical strength. The MFR of the aliphatic-aromatic polyester resin (B) can be adjusted by the molecular weight.

The melting point of the aliphatic-aromatic polyester resin (B) is usually 60 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. or higher, preferably 150 ° C. or lower, more preferably 140 ° C. or higher. Below, it is particularly preferably 120 ° C. or less. When there are a plurality of melting points, it is preferable that at least one melting point is within the above range.
The elastic modulus of the aliphatic-aromatic polyester resin (B) is preferably 180 to 1000 MPa.
When the melting point is out of the above range, the moldability is inferior, and when the elastic modulus is less than 180 MPa, a problem is likely to occur in the moldability, while when the elastic modulus exceeds 1000 MPa, the impact resistance tends to be deteriorated.

The method for adjusting the melting point and elastic coefficient of the aliphatic-aromatic polyester resin (B) is not particularly limited, but for example, the type of copolymerization component of the aliphatic dicarboxylic acid component other than the aromatic dicarboxylic acid component can be selected. It can be adjusted by adjusting the copolymerization ratio of each or by combining them.

In the present invention, the aliphatic-aromatic polyester resin (B) is not limited to one type, and two or more kinds of aliphatic-aromatic polyester resins having different types of constituent units, ratios of constituent units, manufacturing methods, physical characteristics, etc. (B) can be blended and used.

<Alphatic oxycarboxylic acid resin (C)>
The aliphatic oxycarboxylic acid-based resin (C) used in the present invention contains an aliphatic oxycarboxylic acid unit as a main constituent unit, and the aliphatic oxycarboxylic acid unit is represented by the following formula (3). Is preferable.
-OR ^3- CO- (3)
(In the above formula (3), R ³ represents a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group.)

Specific examples of the aliphatic oxycarboxylic acid component giving the aliphatic oxycarboxylic acid unit of the formula (3) include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 2-hydroxy-3, Examples thereof include 3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, and mixtures thereof. When optical isomers are present in these, either D-form or L-form may be used. Of these, lactic acid or glycolic acid is preferred. Two or more kinds of these aliphatic oxycarboxylic acid components can be mixed and used.

As the aliphatic oxycarboxylic acid-based resin (C), polylactic acid (PLA) is particularly preferable.

Further, a urethane bond, an amide bond, a carbonate bond, an ether bond and the like can be introduced into the aliphatic oxycarboxylic acid resin (C) as long as the biodegradability is not affected.

The method for producing the aliphatic oxycarboxylic acid-based resin (C) is not particularly limited, and the aliphatic oxycarboxylic acid-based resin (C) can be produced by a known method such as a direct polymerization method of oxycarboxylic acid or a ring-opening polymerization method of a cyclic substance.

The molecular weight of the aliphatic oxycarboxylic acid resin (C) used in the present invention can be measured by gel permeation chromatography (GPC), and the weight average molecular weight (Mw) using monodisperse polystyrene as a standard substance. However, it is usually 10,000 or more and 1,000,000 or less, but is preferably 20,000 or more and 500,000 or less, more preferably 50,000 or more and 400,000 or less because it is advantageous in terms of moldability and mechanical strength. It is as follows.

The melt flow rate (MFR) of the aliphatic oxycarboxylic acid resin (C) is a value measured at 190 ° C. and a load of 2.16 kg based on JIS K7210 (1999), and is usually 0.1 g / 10 minutes or more and 100 g. It is / 10 minutes or less, but from the viewpoint of moldability and mechanical strength, it is preferably 50 g / 10 minutes or less, and particularly preferably 40 g / 10 minutes or less. The MFR of the aliphatic oxycarboxylic acid resin (C) can be adjusted by the molecular weight.

The melting point of the aliphatic oxycarboxylic acid resin (C) is preferably 70 ° C. or higher, more preferably 75 ° C. or higher, preferably 170 ° C. or lower, more preferably 150 ° C. or lower, and particularly preferably less than 130 ° C. Is. When there are a plurality of melting points, it is preferable that at least one melting point is within the above range.
The elastic modulus of the aliphatic oxycarboxylic acid resin (C) is preferably 180 to 1000 MPa.
When the melting point is out of the above range, the moldability is inferior, and when the elastic modulus is less than 180 MPa, a problem is likely to occur in the moldability, while when the elastic modulus exceeds 1000 MPa, the impact resistance tends to be deteriorated.

The method for adjusting the melting point and elastic modulus of the aliphatic oxycarboxylic acid-based resin (C) is not particularly limited, but for example, the type of copolymerization component other than the aliphatic oxycarboxylic acid can be selected, or each copolymerization can be performed. It can be adjusted by adjusting the ratio or combining them.

As the aliphatic oxycarboxylic acid-based resin (C), the polyhydroxyalkanoate (D) described below can also be preferably used.
The polyhydroxyalkanoate (hereinafter, may be referred to as PHA) (D) preferably used in the present invention has a general formula: [-CHR-CH _2- CO-O-] (in the formula, R is the number of carbon atoms). It is an aliphatic polyester containing a repeating unit represented by 1 to 15 alkyl groups), and is a copolymer containing a 3-hydroxybutyrate unit and a 3-hydroxyhexanoate unit as main constituent units.

From the viewpoint of moldability and thermal stability, the polyhydroxyalkanoate (D) used in the present invention preferably contains 80 mol% or more of 3-hydroxybutyrate units as a constituent component, and more preferably 85 mol% or more. preferable. Further, those produced by microorganisms are preferable. Specific examples of polyhydroxyalkanoate (D) include poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin and poly (3-hydroxybutyrate-co-3-hydroxyvalerate-). Co-3-hydroxyhexanoate) copolymer resin and the like can be mentioned.
In particular, a poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin, that is, PHBH is preferable from the viewpoint of molding processability and physical properties of the obtained molded product.

In polyhydroxyalkanoate (D), a comonomer such as 3-hydroxybutyrate (hereinafter, may be referred to as 3HB) and 3-hydroxyhexanoate copolymerized (hereinafter, may be referred to as 3HH). As for the composition ratio with, that is, the monomer ratio in the copolymer resin, 3-hydroxybutyrate / comonomer = 97/3 to 80/20 (mol% / mol%) from the viewpoint of molding processability and molded product quality. It is preferably 95/5 to 85/15 (mol% / mol%), and more preferably 95/5 to 85/15 (mol% / mol%). If the comonomer ratio is less than 3 mol%, it may be difficult to perform molding because the molding processing temperature and the thermal decomposition temperature are close to each other. If the comonomer ratio exceeds 20 mol%, the crystallization of polyhydroxyalkanoate (D) may be delayed and the productivity may be deteriorated.

The ratio of each monomer in the polyhydroxy alkanoate (D) can be measured by gas chromatography as follows.
To about 20 mg of dry PHA, 2 ml of a sulfuric acid / methanol mixed solution (15/85 (mass ratio)) and 2 ml of chloroform are added and sealed, and heated at 100 ° C. for 140 minutes to obtain a methyl ester of a PHA decomposition product. After cooling, 1.5 g of sodium hydrogen carbonate is added little by little to neutralize the mixture, and the mixture is left to stand until the generation of carbon dioxide gas stops. After adding 4 ml of diisopropyl ether and mixing well, the monomer unit composition of the PHA decomposition product in the supernatant is analyzed by capillary gas chromatography to determine the ratio of each monomer in the copolymer resin.

The weight average molecular weight of the polyhydroxyalkanoate (D) used in the present invention (hereinafter, may be referred to as Mw) can be measured by the above-mentioned gel permeation chromatography (GPC), and is monodisperse polystyrene. The weight average molecular weight (Mw) of the standard substance is usually 200,000 or more and 2,500,000 or less, but is preferably 250,000 or more and 2,000 or more because it is advantageous in terms of moldability and mechanical strength. It is 000 or less, more preferably 300,000 or more and 1,000,000 or less. If the weight average molecular weight is less than 200,000, the mechanical properties and the like may be inferior, and if it exceeds 2,500,000, molding may become difficult.

The melt flow rate (MFR) of polyhydroxyalkanoate (D) is a value measured at 190 ° C. and a load of 2.16 kg based on JIS K7210 (1999), and is preferably 1 g / 10 minutes or more and 100 g / 10 minutes or less. However, from the viewpoint of moldability and mechanical strength, it is more preferably 80 g / 10 minutes or less, and particularly preferably 50 g / 10 minutes or less. The MFR of polyhydroxy alkanoate (D) can be adjusted by molecular weight.

The melting point of the polyhydroxyalkanoate (D) is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, preferably 180 ° C. or lower, more preferably 170 ° C. or lower, and particularly preferably less than 160 ° C. When there are a plurality of melting points, it is preferable that at least one melting point is within the above range.

Polyhydroxyalkanoate (D) is, for example, the Alcaligenes europhos AC32 strain (International deposit based on the Budapest Treaty, International Depositary Authority: Patent of the Institute of Industrial Technology, Incorporated Administrative Agency) in which the PHA synthase gene derived from Aeromonas caviae was introduced into Alcaligenes europhos. Biological Deposit Center (1-1-1, Central 6th, East, Tsukuba City, Ibaraki Prefecture, Japan), Hara Deposit date: Transferred on August 12, 1996, August 7, 1997, Deposit number FERM BP-6038 (Hara) (Transferred from Deposited FERM P-15786))) (J. Bacteriol., 179, 4821 (1997)) and the like.

As the polyhydroxy alkanoate (D), a commercially available product can also be used, and as a commercially available product of the polyhydroxy alkanoate (D) containing a 3-hydroxybutyrate unit and a 3-hydroxyhexanoate unit as a main constituent unit, a commercially available product can be used. , "PHBH X331N", "PHBH X131A", "PHBH X151A", etc. manufactured by Kaneka Corporation can be used.

In the present invention, the aliphatic oxycarboxylic acid resin (C) including the polyhydroxyalkanoate (D) is not limited to one type, but two types having different types of constituent units, constituent unit ratios, production methods, physical properties, etc. The above aliphatic oxycarboxylic acid resin (C) can be blended and used.

<Other ingredients>
In addition to the biodegradable accelerator of the present invention, the biodegradable resin composition of the present invention includes fillers (fillers), plasticizers, antistatic agents, antioxidants, light stabilizers, ultraviolet absorbers, dyes, pigments. , Anti-hydrogenation agent, Crystal nucleating agent, Anti-blocking agent, Weather resistant agent, Heat stabilizer, Flame retardant, Mold release agent, Antifogging agent, Surface wetting improver, Incineration aid, Dispersion aid, Various surfactants, One or more of various additives such as a slip agent may be contained as "other components".
Further, the biodegradable resin composition of the present invention may also contain a freshness-preserving agent, an antibacterial agent and the like as a functional additive.

These other components can be arbitrarily blended as long as the effects of the present invention are not impaired, and one type may be used alone or two or more types may be used in combination.

Since the content of these other components in the biodegradable resin composition of the present invention usually does not impair the physical properties of the biodegradable resin composition of the present invention, the total amount of the other components is the raw material of the present invention. It is preferably 0.01% by mass or more and 40% by mass or less with respect to the total amount of the degradable resin composition.

<Manufacturing method of biodegradable resin composition>
The biodegradable resin composition of the present invention is produced by kneading the above-mentioned biodegradable resin and the biodegradable accelerator of the present invention in a kneader and dispersing the biodegradable resin in the biodegradable resin. Will be done. Further, along with the biodegradation accelerator and the biodegradable resin, other resins and other components used as needed may be mixed in the kneader.

In this mixing step, the biodegradable accelerator and the biodegradable resin and other resins and other components used as needed are mixed in a predetermined ratio at the same time or in an arbitrary order, in a tumbler, a V-type blender, and now. It is mixed by a mixer such as a tar mixer, a Banbury mixer, a kneading roll, an extruder, and preferably further melt-kneaded.

The kneader used in the mixing step may be a melt kneader. The extruder may be either a twin-screw extruder or a single-screw extruder, but a twin-screw extruder is more preferable.

The temperature during melt-kneading is preferably 140 to 220 ° C. Within this temperature range, the time required for the melting reaction can be shortened, deterioration of the color tone due to deterioration of the resin and carbonization of the biodegradation accelerator can be prevented, and impact resistance and moisture heat resistance can be prevented. It is possible to further improve the physical characteristics in terms of practical use such as. From the same viewpoint, the melt-kneading temperature is more preferably 150 to 210 ° C.

As for the melt-kneading time, it is necessary to avoid unnecessary lengthening from the viewpoint of more reliably avoiding resin deterioration and the like as described above, and it is preferably 20 seconds or more and 20 minutes or less, more preferably 30 seconds. It is more than 15 minutes and less. Therefore, it is preferable to set the conditions of the melt-kneading temperature and time so as to satisfy the melt-kneading condition.

[Molded product]
The biodegradable resin composition of the present invention can be molded by various molding methods applied to general-purpose plastics. Examples of the molding method include compression molding (compression molding, laminate molding, stampable molding), injection molding, extrusion molding and co-extrusion molding (film molding by inflation method and T-die method, laminate molding, pipe molding, electric wire / cable molding). , Deformed material molding), hot press molding, hollow molding (various blow molding), calendar molding, solid molding (uniaxial stretching molding, biaxial stretching molding, roll rolling molding, stretch orientation non-woven molding, thermal molding (vacuum molding, pressure emptying) Molding), plastic processing, powder molding (rotary molding), various non-woven molding (dry method, bonding method, entanglement method, spunbond method, etc.), etc. Among them, injection molding, extrusion molding, compression molding, or hot pressing. Molding, especially extrusion molding or injection molding, is preferably applied. As a specific shape, application to a sheet, a film, or a container is preferable.

Further, the biodegradable resin molded product of the present invention formed by molding the biodegradable resin composition of the present invention has a chemical function, an electrical function, a magnetic function, a mechanical function, and a friction / wear / lubrication function. It is also possible to perform various secondary processing for the purpose of imparting surface functions such as optical function, thermal function, and biocompatibility. Examples of secondary processing include embossing, painting, adhesion, printing, metallizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, etc.) Coating, etc.) and the like.

When the molded product obtained by molding the biodegradable resin composition of the present invention is a biodegradable resin molded product having a thin portion having a thickness of 50 μm or more and 4 mm or less in whole or a part thereof, that is, the whole. Is a film-like, sheet-like or plate-like product having a thickness of 50 μm or more and 4 mm or less, or a biodegradable resin molded product having such a film-like, sheet-like or plate-like thin-walled portion as a part thereof. In particular, the effect of developing mechanical strength by containing the biodegradability accelerator of the present invention is effectively exhibited, which is preferable. In this case, the particle size of the biodegradation accelerator of the present invention is preferably 15 μm or less, particularly preferably 10 μm or less as described above.

[Use]
The resin molded product of the present invention composed of the biodegradable resin composition of the present invention is a packaging material for packaging various foods, chemicals, miscellaneous goods and other liquids, powders and solids, agricultural materials, and construction. It is suitably used in a wide range of applications such as materials. Specific uses include injection molded products (eg, fresh food trays, fast food containers, coffee capsule containers, cutlery, outdoor leisure products, etc.), extruded products (eg, films, sheets, fishing threads, fishing nets, etc.). Examples include vegetation nets, secondary processing sheets, water retention sheets, etc.), hollow molded products (bottles, etc.), and the like. In addition, other agricultural films, coating materials, fertilizer coating materials, seedling raising pots, laminated films, boards, stretched sheets, monofilaments, non-woven fabrics, flat yarns, staples, crimped fibers, streaked tapes, split yarns, composite fibers, Blow bottle, shopping bag, trash bag, compost bag, cosmetic container, detergent container, bleaching agent container, rope, binding material, sanitary cover stock material, cold storage box, cushioning material film, multifilament, synthetic paper, surgery for medical use Examples thereof include threads, sutures, artificial bones, artificial skins, DDSs such as microcapsules, and wound covering materials.

In particular, the resin molded product of the present invention is suitable as a container for food such as a container for coffee capsules, a film for food packaging, a tray for fresh food, a container for fast food, and a lunch box. These usually have a thin portion of 50 μm or more and 4 mm or less, and the effect of the biodegradation accelerator of the present invention is effectively exhibited.

Hereinafter, the content of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded. The values of various production conditions and evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable ranges are the above-mentioned upper limit or lower limit values and the following. It may be in the range specified by the value of Examples or the combination of the values of Examples.

[Measurement and calculation of cellulose, lignin, and hemicellulose contents]
The contents of cellulose, lignin, and hemicellulose were determined by the following formulas from the values of heat-resistant α-amylase-treated neutral detergent fiber (aNDFom), acidic detergent fiber (ADFom), and acidic detergent lignin (ADL). ..
Cellulose (%) = ADFom (%) -ADL (%)
Lignin (%) = ADL (%)
Hemicellulose (%) = aNDFom (%) -ADFom (%)
aNDFom, ADFom, and ADL are common methods (for example, "Feed Analysis Method / Explanation 2009" published by Japan Scientific Feed Association, "Feed Analysis Standards" (http://www.famic.go.), National Agriculture and Forestry Consumption Safety Technology Center. jp / ffis / fed / bunseki / bunsekikijun.html), National Research and Development Corporation, National Agriculture and Food Research Organization "Recent Trends in Research on Nutrition Evaluation of Forage Crop" (http://www.naro.affrc.go) .Jp / nigs-neo / kenkyukai / files / jikiyusirioriyo2016_koen07.pdf) and the like).
The outline of the measurement method is as follows.

<< aNDFom >>
Sodium sulfite and a neutral detergent solution are added to a sample (mass W1) and boiled, and then heat-resistant α-amylase is added and boiled. The insoluble matter is filtered out with a glass filter or the like, washed, dried and weighed (W2). Next, this insoluble matter is heated and incinerated and weighed (W3). Obtain aNDFom (%) from the following formula.
aNDFom (%) = 100 × (W2-W3) / W1

<< ADFom and ADL >>
An acidic detergent solution is added to a sample (mass W4) and boiled, and then the insoluble matter is filtered through a glass filter or the like, washed, dried and weighed (W5). Next, after treating this insoluble matter with 72% sulfuric acid, the insoluble matter is washed, dried and weighed (W6). Finally, the insoluble material is heated to ash and weighed (W7). ADFom (%) and ADL (%) are calculated from the following formulas.
ADFom (%) = 100 × (W5-W7) / W4
ADL (%) = 100 × (W6-W7) / W4

Table 1 shows the contents of cellulose, lignin and hemicellulose and the cellulose / hemicellulose ratio obtained by the above method for each of the raw materials used in the following Examples and Comparative Examples.

[Manufacturing method of biodegradation accelerator (1)]
Each raw material was crushed by a crush miller (“IFM-C20G” manufactured by Iwatani Corporation), passed through a 50 mesh (opening 297 μm) sieve, and dried at 80 ° C. for 12 hours in a dryer. The moisture content of the poplar wood flour after drying in the dryer was 0.3%, the moisture content of the walnut shell flour was 0.8%, and the moisture content of the defatted rice bran was 2.0%.

[Manufacturing method of biodegradation accelerator (2)]
Commercially available dry degreased rice bran (“BFR-5” manufactured by Bosoh Oil & Fat Co., Ltd. (standard moisture content 5% or less)) is used with a jet mill crusher (“NJ-100” manufactured by Aisin Nano Technologies), and the air pressure is 1.4 MPa. The mixture was pulverized under the conditions of an input amount of 1 kg / h to 8 kg / h per hour. Depending on the pulverization conditions, a biodegradation accelerator (defatted rice bran) having an average particle size of 8 μm, 11 μm, and 14 μm, which will be described later, was obtained.

[Measuring method of particle size of biodegradation accelerator]
The particle size of the biodegradation accelerator was measured using a laser diffraction type particle size distribution measuring device (“SALD-2300” manufactured by Shimadzu Corporation), and the average particle size was determined by the following method. That is, the pattern of diffracted scattered light observed by irradiating the particles of the biodegradation accelerator dispersed in a dispersion medium such as water, alcohol, or air with laser light, and a large number of biodegradation accelerators having different diameters. By comparing the patterns of diffracted scattered light estimated by calculation when regarded as an aggregate of spherical particles, the distribution of the particle size and the number of particles so as to match them is calculated. With respect to the distribution of the particle size and the number of particles thus obtained, the number average particle size obtained by dividing the sum of the particle sizes (diameters) by the total number of particles was defined as the average particle size.

[Measuring method of water content of biodegradation accelerator]
The weighed biodegradation accelerator was placed in an aluminum dish, dried in a hot air dryer at 135 ° C. for 2 hours, allowed to cool, weighed, and the weight loss was divided by the original weight to calculate the moisture content. ..

[Biodegradable resin]
As the biodegradable resin, the following aliphatic polyester resin (A), aliphatic-aromatic polyester resin (B), aliphatic oxycarboxylic acid resin (C), and polyhydroxy alkanoate (D) are used. There was.
Aliphatic polyester resin (A-1): Polybutylene succinate adipate (PBSA) PTTMCC Biochem, Inc. Product name BioPBS ^TM FD92PB
Aliphatic polyester resin (A-2): Polybutylene succinate (PBS) "BioPBS ^TM FZ91PB" manufactured by PTTMCC Biochem.
Aliphatic-aromatic polyester resin (B): Polybutylene adipate terephthalate (PBAT) BASF's "ecoflex ^TM F Blend C1200"
Aliphatic oxycarboxylic acid resin (C): Polylactic acid (PLA) "Ingeo ^TM 4060D" manufactured by Nature Works.
Polyhydroxyalkanoate (D): Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH): "PHBH ^TM X131A" manufactured by Kaneka Corporation

[Examples 1 to 6, Comparative Examples 1 to 3]
The biodegradation accelerator obtained by the aliphatic polyester resin (A-1) and the production method (1) is blended in the ratio shown in Table 2 and is a small twin-screw kneader (DSM "Xplore Micro 15cc Twin Screw Compounder"). ”) Was used to melt and knead at 190 ° C. for 5 minutes in a nitrogen atmosphere.
The obtained resin composition is injection-molded at a mold temperature of 40 ° C. and a cylinder temperature of 190 ° C. using an 18-ton injection molding machine (SE18D manufactured by Sumitomo Heavy Industries, Ltd.) to obtain an ISO test piece for mechanical property test. It was.

[Examples 7 to 12, Comparative Examples 4 to 6]
The biodegradation accelerator obtained by the aliphatic polyester resin (A-1) and the production method (1) is blended in the ratio shown in Table 3, and a small twin-screw kneader (DSM "Xplore Micro 15cc Twin Screw Compound"" ”) Was used to melt and knead at 170 ° C. for 5 minutes in a nitrogen atmosphere.
The obtained resin composition was injection-molded at a mold temperature of 40 ° C. and a cylinder temperature of 170 ° C. using a small injection molding machine (“Xplore Micro 12cc Injection Molding Machine” manufactured by DSM), and ISO for mechanical property test. A test piece was obtained.

[Examples 13 to 18, Comparative Examples 7 to 10]
The biodegradable resin shown in Table 4 and the biodegradable accelerator shown in Table 4 obtained by the production method (1) are blended in the ratio shown in Table 4, and a small twin-screw kneader (“Xplore Micro 15cc” manufactured by DSM) is blended. Using a Twin Screw Composer), melt-kneading was carried out at 170 ° C. for 4 minutes in a nitrogen atmosphere.

[Examples 19 to 20, Comparative Example 11]
The aliphatic polyester resin (A-2) and the biodegradation accelerator (average particle size 11 μm) obtained by the production method (2) are blended in the ratio shown in Table 5, and a twin-screw kneading extruder (Japan Steel Works, Ltd.) Kneading was performed at a set temperature of 135 ° C., a screw rotation speed of 200 rpm, and a discharge rate of 20 kg / h using the Japan Steel Works "TEX30α"), and after passing the extruded strands through a water tank, they were cut with a strand cutter to obtain pellets. It was. The obtained pellets are dried at 60 ° C. for 5 hours with a hot air dryer, and then subjected to a mold temperature of 40 ° C. and a cylinder temperature of 140 ° C. using an 18-ton injection molding machine (“SE18D” manufactured by Sumitomo Heavy Industries, Ltd.). And injection molding was performed to obtain an ISO test piece for mechanical property test.

[Examples 21 to 22, Comparative Example 12]
The aliphatic polyester resin (A-2) and the biodegradation accelerator (average particle size 11 μm) obtained by the production method (2) are blended at the ratio shown in Table 6 and a twin-screw kneading extruder (Japan Steel Works, Ltd.). Kneading was performed at a set temperature of 135 ° C., a screw rotation speed of 200 rpm, and a discharge rate of 20 kg / h using the Japan Steel Works "TEX30α"), and after passing the extruded strands through a water tank, they were cut with a strand cutter to obtain pellets. It was. The obtained pellets were dried at 60 ° C. for 5 hours with a hot air dryer, and then molded using a single-layer T die sheet molding machine (“JU-1709” manufactured by GSI Creos Corporation) to form a sheet having a thickness of 0.8 mm. A molded product was obtained.

[Examples 23 to 24, Reference Example 1]
Table 7 shows the aliphatic polyester resin (A-1) and the biodegradation accelerators (average particle size 8 μm and 11 μm) or unmilled defatted rice bran (average particle size 123 μm) obtained by the production method (2). Blend at a ratio and knead using a twin-screw kneading extruder (“TEX30α” manufactured by Japan Steel Works, Ltd.) at a set temperature of 125 ° C., a screw rotation speed of 200 rpm, and a discharge rate of 20 kg / h to extrude the strands. After passing through a water tank, it was cut with a strand cutter to obtain pellets. The obtained pellets were dried at 60 ° C. for 5 hours with a hot air dryer and then molded with a single-layer inflation molding machine (“Engineering Plastic 30” manufactured by Engineering Plastic Industry Co., Ltd.) to obtain a film-shaped molded product having a thickness of 30 μm. It was.

[Examples 25 to 27, Comparative Example 13]
Table 8 shows the proportions of the aliphatic polyester resin (A-1) and the biodegradation accelerators (average particle size 8 μm and 14 μm) or unmilled defatted rice bran (average particle size 123 μm) obtained by the production method (2). Kneading at a set temperature of 125 ° C., screw rotation speed of 200 rpm, and discharge rate of 20 kg / h using a twin-screw kneading extruder (“TEX30α” manufactured by Japan Steel Works, Ltd.), and extruded strands in a water tank. After passing through, the pellets were obtained by cutting with a strand cutter.

The resin compositions and molded articles obtained in Examples 1 to 27, Comparative Examples 1 to 13 and Reference Example 1 were evaluated as follows, and the results are shown in Tables 2 to 8.

<Biodegradability test (Method A)>
The obtained resin composition was made into a film having a thickness of 100 μm by a hot press molding machine at 190 ° C., cut into a dumbbell shape conforming to ISO527-3, and a garden soil having a water content of 20% RH (manufactured by Iris Oyama Co., Ltd. It was buried in the soil of a polyethylene tapper container containing "cultivated soil for flowers and vegetables"), closed the lid, and allowed to stand in an inert oven at 28 ° C. for 1 week. The weight change before and after standing was measured, and the rate of change (ratio of mass loss to mass before standing) was calculated. The calculated rate of change was calculated as a ratio to the rate of change in the case of only the aliphatic polyester resin (A-1) of Comparative Example 1 tested at the same time, and used as the biodegradability improvement rate (method A).

<Biodegradability test (Method B)>
The obtained resin composition was made into a film having a thickness of 200 μm by a hot press molding machine at 180 ° C., cut into a dumbbell shape conforming to ISO527-3, and placed in a polyethylene tapper container with a water content of 20% RH. (Iris Oyama Co., Ltd. "Cultivated soil for flowers and vegetables") and compost (manufactured by Yawata Bussan Co., Ltd., planting source for biodegradation test) are buried in a mixture with a mass ratio of 1: 1 and the lid is closed 28. It was allowed to stand in an inert oven at ° C for 2 weeks. The weight change before and after standing was measured, and the rate of change (ratio of mass loss to mass before standing) was calculated. The calculated rate of change was calculated as a ratio to the rate of change in the case of only the aliphatic polyester resin (A-1) of Comparative Example 4 tested at the same time, and used as the biodegradability improvement rate (method B).

<Biodegradability test (C method)>
The obtained resin composition was made into a film having a thickness of 100 μm by a hot press molding machine at 180 ° C., cut into a rectangle of 30 mm × 20 mm, and placed in a polyethylene tapper container with a water content of 20% RH for gardening soil (Iris Oyama). It is buried in a mixture of "Flower and vegetable culture soil" manufactured by Yawata Co., Ltd.) and compost (manufactured by Yawata Bussan Co., Ltd., a planting source for biodegradation test) with a mass ratio of 1: 1. It was allowed to stand in the cabin for 3 weeks. The weight change before and after standing was measured, and the rate of change (ratio of mass loss to mass before standing) was calculated. Comparative Examples using only biodegradable resins in which the calculated rate of change was tested at the same time (Examples 13 to 15 are Comparative Example 7, Example 16 is Comparative Example 8, Example 17 is Comparative Example 9, and Example 18 is It was calculated as a ratio to the rate of change in Comparative Example 10) and used as the biodegradability improvement rate (method C).

<Biodegradability test (D method)>
The obtained resin composition was made into a film having a thickness of 100 μm by a hot press molding machine at 180 ° C., cut into a rectangle of 50 mm × 30 mm, and placed in a polyethylene tapper container with a water content of 20% RH for gardening soil (Iris Oyama). It is buried in a mixture of "Flower and vegetable culture soil" manufactured by Yawata Co., Ltd.) and compost (manufactured by Yawata Bussan Co., Ltd., a planting source for biodegradation test) with a mass ratio of 1: 1. It was allowed to stand in the cabin for 5 weeks. The weight change before and after standing was measured, and the weight change rate (ratio of mass loss to mass before standing (percentage)) was calculated.

<MFR>
The melt flow rate (MFR) of the obtained resin composition was measured at 190 ° C. and a load of 2.16 kg. The MFR is preferably in the range of 0.1 to 30 g / 10 min, although it depends on the molding method.

<Bending characteristics>
The flexural modulus and flexural strength of the ISO test piece for mechanical property test were measured in accordance with JIS K 7171 (2008). It is preferable that the flexural modulus is 0.4 GPa or more, which is larger. The bending strength is preferably 40 MPa or more, which is larger.

<Heat resistance>
Regarding the ISO test piece for mechanical property test, the deflection temperature under load (HDT) was measured by the B method flatwise (0.45 MPa) in accordance with JIS K 7191-2 (2007). The HDT is preferably 65 ° C. or higher, more preferably 68 ° C. or higher.

<Impact resistance>
The Charpy impact strength of the ISO test piece for mechanical property test was measured in accordance with JIS K 711-1 (2012). The Charpy impact strength is ^{preferably 3 kJ / m 2} or more, and the larger it is.

<Density of biodegradable resin composition>
Using an ISO test piece for mechanical property test, measurement was performed at 23 ° C. with an automatic hydrometer (D-H100 manufactured by Toyo Seiki Co., Ltd.).

<Density of biodegradation accelerator>
It was calculated from the density of the above biodegradable resin composition and the density of only the biodegradable resin containing no biodegradable resin accelerator of Comparative Example 1.

<Tensile characteristics>
For the sheet-shaped molded product, the tensile elastic modulus and the elongation at break were measured in accordance with JIS K7127 (1999). The larger these values are, the more preferable.

<Tear strength>
For the film-shaped molded product, the Elmendorf tear strength was measured according to ISO6383-2 (1983). The larger this value is, the more preferable it is.

<Puncture impact strength>
Using a punching impact tester manufactured by Toyo Seiki Co., Ltd., a film-shaped molded body with a width of 110 mm and a length of 1300 mm was used as a sample, and 12 holes with a diameter of 50 mm were punched out with a hemispherical arm with a tip of 25 mm in diameter and punctured. Char impact strength was measured. The larger this value is, the more preferable it is.

<Evaluation of appearance>
The appearance of the sheet-shaped molded product and the film-shaped molded product was evaluated. Those with a smooth surface and non-uniform parts that could not be seen with the naked eye were rated as "good", and those with a non-uniform appearance were rated as "poor".

From Tables 2 to 4, the biodegradability of the biodegradable resin is further improved while maintaining the mechanical properties by using the biodegradation accelerator of the present invention containing cellulose, hemicellulose and lignin in a predetermined ratio. You can see that you can.

From Tables 5 to 8, by using a biodegradation accelerator containing cellulose, hemicellulose and lignin in a predetermined ratio and having a particle size within a predetermined range, the biodegradation accelerator has good mechanical properties and appearance, and is excellent. It can be seen that a biodegradable resin molded product having biodegradability can be obtained.

Claims (8)

A decomposition accelerator for biodegradable resins containing cellulose, hemicellulose and lignin, which contains 10% by mass or more and 30% by mass or less of lignin with respect to a total of 100% by mass of cellulose, hemicellulose and lignin, and cellulose with respect to the content of hemicellulose. Decomposition accelerator for biodegradable resins having a content ratio of 0.5 to 4.0. The decomposition accelerator for a biodegradable resin according to claim 1, which is a powder or granular material and has a particle size of 15 μm or less. A biodegradable resin composition containing 2 parts by mass or more and 250 parts by mass or less of the decomposition accelerator for biodegradable resin according to claim 1 or 2 and 100 parts by mass of the biodegradable resin. Claimed that the biodegradable resin is at least one selected from the group consisting of an aliphatic polyester resin (A), an aliphatic-aromatic polyester resin (B) and an aliphatic oxycarboxylic acid resin (C). Item 3. The biodegradable resin composition according to Item 3. The biodegradable resin composition according to claim 4, wherein the aliphatic polyester resin (A) contains a repeating unit derived from an aliphatic diol and a repeating unit derived from an aliphatic dicarboxylic acid as a main constituent unit. Claimed that the aliphatic-aromatic polyester resin (B) contains a repeating unit derived from an aliphatic diol, a repeating unit derived from an aliphatic dicarboxylic acid, and a repeating unit derived from an aromatic dicarboxylic acid as main constituent units. Item 4. The biodegradable resin composition according to Item 4. A biodegradable resin molded product which is an extrusion molded product or an injection molded product of the biodegradable resin composition according to any one of claims 3 to 6. The biodegradable resin molded product according to claim 7, wherein the extruded molded product or the injection molded product has a thin portion having a thickness of 50 μm or more and 4 mm or less.