WO2021201186A1

WO2021201186A1 - Biodegradable resin composition and molded article

Info

Publication number: WO2021201186A1
Application number: PCT/JP2021/014071
Authority: WO
Inventors: 悠太池田; 加藤　聡; 野口　浩; 玲美宮町
Original assignee: 三菱ケミカル株式会社
Priority date: 2020-03-31
Filing date: 2021-03-31
Publication date: 2021-10-07
Also published as: JPWO2021201186A1

Abstract

A biodegradable resin composition containing a resin having a glass transition temperature not higher than 40°C and polysaccharides including an amino sugar, wherein the contained amount of the polysaccharides including the amino sugar is 0.01-30 wt%.　The present invention can provide a biodegradable resin composition that has a rapid biodegradation rate and a high biodegradation degree.

Description

Biodegradable resin composition and molded article

The present invention relates to a biodegradable resin composition and a molded product containing the biodegradable resin composition.

In modern society, plastic is light and has excellent electrical insulation, molding processability, durability, etc., so it is used in a wide range of personal applications such as packaging materials, home appliance materials, and building materials. Plastics used for these purposes include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate and the like. However, since these plastic molded products are not easily decomposed in a natural environment, they tend to remain in the ground even if they are buried after use. In addition, even if it is incinerated, it may generate harmful gas and damage the incinerator. In recent years, from the viewpoint of preventing environmental pollution, products that can be composted at home (home compostable products). ) Is required.

As a means for solving the above-mentioned problems, research has been conducted on biodegradable materials that are decomposed into carbon dioxide and water by microorganisms in compost. Typical examples of biodegradable materials include biodegradable resins such as polylactic acid (hereinafter, may be abbreviated as "PLA").

However, no studies have been conducted on resins that biodegrade in the ocean.

An object of the present invention is to provide a biodegradable resin composition having a high biodegradation rate and a high degree of biodegradation. Another object of the present invention is to provide a biodegradable resin composition having a high biodegradation rate and a high degree of biodegradation, particularly in the ocean.

The present inventors diligently examined in view of the above circumstances. Specifically, we focused on polysaccharides containing amino sugars, and thought that polysaccharides containing amino sugars would contribute to the promotion of decomposition. As a result, the present inventors have obtained a remarkable biodegradation-promoting effect by blending a specific amount of a polysaccharide containing an amino sugar with a resin having a glass transition temperature of a specific temperature or lower. We have found that the problem can be solved and completed the present invention. That is, the gist of the present invention is as follows.

[1] A biodegradable resin composition containing a resin having a glass transition temperature of 40 ° C. or lower and a polysaccharide containing an amino sugar, wherein the content of the polysaccharide containing an amino sugar is 0.01% by weight or more. A biodegradable resin composition of 30% by weight or less.
[2] The biodegradable resin composition according to the above [1], wherein the resin is a polyester resin.
[3] The biodegradability according to the above [2], wherein the polyester resin has at least one selected from the group consisting of 1,4-butanediol, 1,3-propanediol and ethylene glycol as a diol unit. Resin composition.
[4] The biodegradable resin composition according to the above [2] or [3], wherein the polyester resin has a dicarboxylic acid having 2 to 22 carbon atoms as a dicarboxylic acid unit.
[5] The biodegradable resin composition according to any one of the above [1] to [4], wherein the resin is a biodegradable resin.
[6] The biodegradable resin composition according to any one of the above [2] to [5], wherein the polyester resin has a tensile elastic modulus of 10 to 2500 MPa.
[7] The biodegradable resin composition according to any one of [1] to [6] above, wherein the polysaccharide is a polysaccharide containing glucosamines.
[8] The biodegradable resin composition according to the above [7], wherein the polysaccharide is chitin.
[9] A molded product containing the biodegradable resin composition according to any one of the above [1] to [8].
[10] A method for biodegrading a polyester resin, which comprises biodegrading a polyester resin having a glass transition temperature of 40 ° C. or lower in seawater in the presence of a polysaccharide containing an amino sugar. ..

According to the present invention, it is possible to provide a biodegradable resin composition having a high biodegradation rate and a high degree of biodegradation, and contributes greatly to solving environmental problems such as marine pollution problems.

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.

Hereinafter, the present invention will be described in detail, but the description of the constituent elements described below is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to these contents. It can be implemented with various modifications within the scope of the abstract.

One embodiment of the present invention is referred to as a biodegradable resin composition containing a resin and a polysaccharide containing an amino sugar (hereinafter, "biodegradable resin composition according to the present embodiment" or "resin composition of the present invention". I may say.). The resin composition of the present invention is preferably a biodegradable resin composition obtained by mixing or kneading a resin and a polysaccharide containing an amino sugar.
In the present specification, "biodegradable" means that the resin is decomposed into small molecules such as oligomers and monomers by the action of microorganisms, and then these are further decomposed into water, carbon dioxide and the like. Means. The resin composition of the present invention may be biodegraded in any environment as long as the resin is biodegraded. In particular, in seawater, the amount and types of microorganisms are small, and the resin is difficult to biodegrade. However, the resin composition of the present invention can exhibit its effect in such an environment where biodegradation is difficult. Therefore, it is preferable that the resin composition of the present invention has high biodegradability in seawater (ocean biodegradable resin composition).
Hereinafter, the constituent components, characteristics, production method and use of the biodegradable resin composition according to the present embodiment will be described.

[Polysaccharides containing amino sugars]
The biodegradable resin composition according to the present embodiment contains a polysaccharide containing an amino sugar (hereinafter, may be referred to as "polysaccharide according to the present invention" or simply "polysaccharide"). Here, the amino sugar means a saccharide having an amino group and a derivative such as an acylated product thereof.
Polysaccharides containing amino sugars are polysaccharides in which amino sugars or amino sugars and other monosaccharides or oligosaccharides are bound via glycosidic bonds. Polysaccharides in which amino sugars are bound to each other via glycosidic bonds are preferable. Polysaccharides containing amino sugars are useful as biodegradation accelerators because they can easily improve the biodegradation rate or the degree of biodegradation of resins as compared with polysaccharides containing no amino sugars such as cellulose and agarose.
Examples of polysaccharides containing amino sugars include chitin, glucosamine, chondroitin, hyaluronic acid, keratan sulfate, heparan sulfate, heparin, dermatan sulfate, and derivatives thereof. Of these, polysaccharides containing glucosamines such as glucosamine and N-acetylglucosamine are preferable, and chitin is more preferable, from the viewpoint of the biodegradability promoting effect.
The method for producing chitin is not particularly limited. For example, it may be made from crustaceans such as crabs or cartilage of squid, or it may be produced by culturing cells. Moreover, either α-chitin or β-chitin can be used. There are no restrictions on the shape of chitin, and it may be in the form of powder or nanofibers.
In the present invention, the resin composition containing chitin and polyhydroxybutyrate in a ratio of 3: 7 (weight ratio) is preferably excluded from the scope of the present invention. Further, the resin composition containing chitin and polyhydroxybutyrate is preferably excluded from the scope of the present invention. Furthermore, it is preferable that polyhydroxybutyrate is removed from the resin in the present invention.

The molecular weight of the polysaccharide containing the amino sugar is preferably small from the viewpoint of promoting the biodegradability and from the viewpoint of easy uniform dispersion in the resin. Therefore, specifically, the molecular weight of the polysaccharide containing an amino sugar is preferably 10,000,000 or less, more preferably 5,000,000 or less. On the other hand, it is usually 3,000 or more, preferably 10,000 or more. The molecular weight of the polysaccharide including amino sugar can be measured by gel permeation chromatography (GPC). When the polysaccharide containing an amino sugar is a polymer, the molecular weight is the weight average molecular weight. When a commercially available product is used as the polysaccharide containing an amino sugar, the molecular weight may be confirmed from the catalog value.
It is preferable that polysaccharides containing amino sugars do not easily inhibit the growth of microorganisms. Moreover, from the viewpoint of safety, it is preferable that it is not a dangerous substance, an insecticide, a pesticide such as a herbicide, or the like.

The biodegradable resin composition contains a polysaccharide containing an amino sugar in an amount of 0.01% by weight or more and 30% by weight or less. The amount of the polysaccharide containing amino sugar contained in the biodegradable resin composition may be appropriately adjusted according to the type of resin, the type of polysaccharide containing amino sugar, the use of the biodegradable resin composition, and the like. good. The content of the polysaccharide containing an amino sugar is preferably 0.05% by weight or more, more preferably 0.1% by weight or more, further preferably 1% by weight or more, and particularly preferably 5% by weight or more. On the other hand, the content is preferably 25% by weight or less, more preferably 20% by weight or less, and further preferably 15% by weight or less. By setting the content of polysaccharides including amino sugars in the biodegradable resin composition within the above range, it is easy to obtain a composition having both biodegradability and mechanical properties when processed into a molded product.

[resin]
The biodegradable resin composition according to the present embodiment contains a resin. The resin contained in the biodegradable resin composition according to the present embodiment is not particularly limited as long as the biodegradability is improved by using the resin composition with the above-mentioned aminosaccharide-containing polysaccharide. The resin contained in the biodegradable resin composition according to the embodiment is preferably a biodegradable resin. The degree of biodegradation of the resin and the biodegradable resin composition according to the present embodiment will be described later. As the resin contained in the biodegradable resin composition according to the present embodiment, one type may be used alone, or two or more types of resins may be used in any combination and ratio.

Polylactic acid and the like are known as biodegradable resins.

As the resin contained in the biodegradable resin composition according to the present embodiment, a polyester resin is preferable because the biodegradability can be easily improved by using a resin composition with a polysaccharide containing an amino sugar. A polyester resin having a carboxylic acid unit such as an acid unit or an oxycarboxylic acid unit is more preferable. Further, a polyester resin having a dicarboxylic acid unit and a diol unit and a polyester resin having an oxycarboxylic acid unit are particularly preferable, and a polyester resin having a dicarboxylic acid unit and a diol unit is most preferable. Specifically, the polyester resins are PBSSe (polybutylene succinate sebacate), PBSeT (polybutylene succinate terephthalate) and PHBH (poly (3-hydroxybutyrate-co-3-hydroxyhexanoate)), PCL. (Polycaprolactone) is particularly preferred.
The polyester resin may be an aliphatic polyester resin, an aromatic polyester resin, or an aliphatic-aromatic polyester resin. However, an aliphatic polyester resin or an aliphatic-aromatic polyester resin is preferable in terms of high flexibility. Here, in the present specification, the aromatics also include complex aromatics.

Even if only one type of resin is used, two or more types of resins having different types of constituent units, constituent unit ratios, manufacturing methods, physical characteristics, etc. can be blended and used.

The resin contained in the biodegradable resin composition according to the present embodiment will be described in detail below by taking a polyester resin as an example. In addition, each repeating unit in a polyester resin is also referred to as a compound unit for a 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 an "aromatic dicarboxylic acid". Also called "acid unit". Further, the "main constituent unit" in the polyester resin is usually a constituent unit in which the constituent unit is contained in an amount of 80% by weight or more in the polyester resin, and does not include a constituent unit other than the main constituent unit. There is also.
The polyester resin contained in the biodegradable resin composition according to the present embodiment includes (1) a polyester resin containing a diol unit and a dicarboxylic acid unit, and (2) a diol unit, a dicarboxylic acid unit and an oxycarboxylic acid unit. Polyester resins, (3) polyester resins containing an oxycarboxylic acid unit, and the like are preferable. Of these, (1) a polyester resin containing a diol unit and a dicarboxylic acid unit, (3) a polyester resin containing an oxycarboxylic acid unit, and the like are more preferable.
The polyester resin contained in the biodegradable resin composition according to the present embodiment is considered to be likely to promote biodegradation due to a decrease in the crystallinity of the polyester resin and an increase in the number of amorphous portions. It is preferable to have two or more types of structural units.

<Polyester resin containing diol unit and dicarboxylic acid unit>
The polyester resin containing a diol unit and a dicarboxylic acid unit will be described in detail.
The diol unit contained in the polyester resin may be aliphatic or aromatic, but from the viewpoint of biodegradability, the aliphatic is preferable, and the diol unit represented by the following general formula (1) is particularly preferable.
-OR ¹ -O- (1)
In the formula (1), R ¹ represents an aliphatic hydrocarbon group having 2 or more carbon atoms and 20 or less carbon atoms.

The carbon number of the aliphatic hydrocarbon group represented by R ¹ is usually 2 or more, preferably 4 or more, and usually 20 or less, preferably 16 or less, more preferably 12 from the viewpoint of moldability, mechanical strength, and the like. Below, it is more preferably 6 or less. A particularly preferable group as the aliphatic hydrocarbon group is an aliphatic hydrocarbon group having 4 carbon atoms.
As the aliphatic diol giving the aliphatic diol unit represented by the formula (1), for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like are preferable. 1,4-Butanediol, 1,3-propanediol and ethylene glycol are more preferable, and 1,4-butanediol is particularly preferable.
As the diol unit contained in the polyester resin, one type or two or more types of units may be used in any combination and ratio. When the polyester resin contains a plurality of types of diol units, the total diol units preferably contain 30 mol% or more of the aliphatic diol units, and more preferably 50 mol% or more. The upper limit is 100 mol%.

The diol unit contained in the polyester resin may contain an aromatic diol unit. Specific examples of the aromatic diol component that gives the aromatic diol unit include, for example, 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 the 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.

The dicarboxylic acid unit contained in the polyester resin may be aliphatic or aromatic. Further, the dicarboxylic acid unit contained in the polyester resin may contain one type or two or more types of units in any combination and ratio, and may contain an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit. good. However, from the viewpoint of biodegradability, the dicarboxylic acid unit preferably contains an aliphatic dicarboxylic acid unit. When the polyester resin contains a plurality of types of dicarboxylic acid units, the aliphatic dicarboxylic acid unit is preferably contained in an amount of 30 mol% or more, more preferably 50 mol% or more, based on all the dicarboxylic acid units. When the aliphatic dicarboxylic acid unit is contained, the upper limit of the aliphatic dicarboxylic acid unit contained in all the dicarboxylic acid units is 100 mol%. When the polyester resin contains an aromatic dicarboxylic acid unit, the aromatic dicarboxylic acid unit is preferably 70 mol% or less, more preferably 60 mol% or less, based on the total dicarboxylic acid unit. ..
The dicarboxylic acid unit contained in the polyester resin is preferably a dicarboxylic acid having 2 to 22 carbon atoms, and the dicarboxylic acid unit has 2 or more carbon atoms from the viewpoint of biodegradability, moldability, and mechanical strength. More preferably, it is more preferably 4 or more, and on the other hand, it is more preferably 16 or less, and further preferably 13 or less.
The dicarboxylic acid unit contained in the polyester resin is preferably oxalic acid or a dicarboxylic acid unit represented by the following general formula (2).
-OC-R ^2- CO- (2)
In the formula (2), R ² represents a single bond, an aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic group having 4 to 8 carbon atoms.

When R ² is an aliphatic hydrocarbon group, the number of carbon atoms of the aliphatic hydrocarbon group is usually 1 or more, preferably 2 or more, more preferably 4 or more, and on the other hand, usually 22 or less, preferably 22 or less. It is 16 or less, more preferably 12 or less, still more preferably 8 or less. When the polyester resin contains two or more kinds of aliphatic dicarboxylic acid units represented by the formula (2), the combination of the aliphatic hydrocarbon groups includes an aliphatic hydrocarbon group having 2 carbon atoms and an aliphatic hydrocarbon group having 4 or more carbon atoms and 10 or less carbon atoms. The combination with the aliphatic hydrocarbon group of is preferable.

The aliphatic dicarboxylic acid component giving the aliphatic dicarboxylic acid unit represented by the formula (2) is not particularly limited, but the carbon number thereof is preferably 2 or more, more preferably 4 or more, and on the other hand, 22 The following is preferable, and 10 or less is more preferable. That is, a derivative such as an aliphatic dicarboxylic acid having 2 or more and 22 or less carbon atoms or an alkyl ester thereof is preferable, and a derivative such as an aliphatic carboxylic acid having 4 or more and 10 or less carbon atoms or an alkyl ester thereof is more preferable.
Preferred aliphatic dicarboxylic acid units include, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid. Of these, adipic acid, succinic acid and sebacic acid are preferable, succinic acid and sebacic acid are more preferable, and succinic acid is particularly preferable.

In the polyester resin, the ratio of the above-mentioned preferable dicarboxylic acid unit to the total dicarboxylic acid unit is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 50 mol% or more. It is preferably 64 mol% or more, and most preferably 68 mol% or more. The upper limit is 100 mol%. By setting the preferable ratio of the dicarboxylic acid in the polyester resin to the above range, it becomes possible to obtain a biodegradable resin composition which is excellent in heat resistance and biodegradability as well as improved moldability.

The polyester resin preferably contains two or more types of aliphatic dicarboxylic acid units, and more preferably contains two or more types of the above-mentioned preferable aliphatic dicarboxylic acid units. In this case, the combination of the aliphatic dicarboxylic acid unit is preferably a combination of an aliphatic dicarboxylic acid unit having 4 carbon atoms and an aliphatic dicarboxylic acid unit having 6 or more and 12 or less carbon atoms, and an aliphatic dicarboxylic acid unit having 4 carbon atoms. Is more preferably combined with an aliphatic dicarboxylic acid unit having 6 or more and 10 or less carbon atoms. Specifically, the combination of the aliphatic dicarboxylic acid units preferably includes at least one unit of succinic acid unit, adipic acid unit, azelaic acid unit, and sebacic acid unit, and two or more of these. It is more preferable to combine the dicarboxylic acid units of.
As the dicarboxylic acid unit to be combined with the succinic acid unit, a pimeric acid unit, a suberic acid unit, an adipic acid unit, an adipic acid unit, a sebacic acid unit, an undecanedioic acid unit or a dodecanedioic acid unit is preferable, and an adipic acid unit or a sebacic acid unit is preferable. The combination with and is more preferable, and the combination with the sebacic acid unit is further preferable.
That is, specifically, the following polyester resins are preferable. As the polyester resin having a succinic acid unit, polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe), polybutylene succinate azelate (PBSAz) and the like are preferable. More preferred are polyester resins having two or more dicarboxylic acid units such as polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe) and polybutylene succinate azelate (PBSAz). As the polyester resin having a sebacic acid unit, polybutylene succinate sebacate (PBSSe), polybutylene sebacate terephthalate (PBSeT) and polybutylene sebacate furanoate (PBSeF) are preferable. As the polyester resin having an azelaic acid unit, polybutylene succinate azelate (PBSAz), polybutylene succinate terephthalate (PBAzT) and the like are preferable. As the polyester resin having an adipic acid unit, polybutylene succinate adipate (PBSA) and polybutylene adipate terephthalate (PBAT) are preferable.

The dicarboxylic acid unit to be combined with the succinic acid unit preferably contains 5 mol% or more, more preferably 10 mol% or more, and 15 mol% or more, based on the total dicarboxylic acid units. On the other hand, it is more preferably contained in an amount of 50 mol% or less, more preferably contained in an amount of 45 mol% or less, and further preferably contained in an amount of 40 mol% or less. By copolymerizing an aliphatic dicarboxylic acid unit other than the succinic acid unit within the above range, the crystallinity of the polyester resin can be lowered and the biodegradation rate can be increased.

The aromatic dicarboxylic acid component that gives the aromatic dicarboxylic acid unit represented by the formula (2) is not particularly limited, but the carbon number thereof is usually 4 or more and 8 or less, preferably 6 or less. Specific examples thereof include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 2,5-frangyl group and the like.

The aromatic dicarboxylic acid component that gives the aromatic dicarboxylic acid unit represented by the formula (2) is not particularly limited, but is usually the above-mentioned aromatic dicarboxylic acid having a preferable carbon number or a derivative thereof. Specific examples thereof include phthalic acid, isophthalic acid, terephthalic acid, 2,5-furandicarboxylic acid and its derivatives, and among them, terephthalic acid and 2,5-furandicarboxylic acid or derivatives thereof are preferable, and 2,5 -Flange carboxylic acid or a derivative thereof is more preferable.

Examples of the derivative of the aromatic dicarboxylic acid include lower alkyl esters of the aromatic dicarboxylic acid having 1 or more and 4 or less carbon atoms, acid anhydrides and the like. Specific examples of the derivative of the aromatic dicarboxylic acid include lower alkyl esters such as the above-mentioned methyl ester, ethyl ester, propyl ester and butyl ester of the aromatic dicarboxylic acid; cyclic acid anhydride of the aromatic dicarboxylic acid; and the like. .. Of these, dimethyl terephthalate is preferable.
As the polyester resin having a dicarboxylic acid unit, a polyester resin having a different amount of the dicarboxylic acid unit may be used. For example, a polyester resin containing only the above-mentioned preferable dicarboxylic acid unit as the dicarboxylic acid unit and a dicarboxylic acid unit other than these may be used. It is also possible to blend with the containing polyester resin to adjust the ratio of the preferable dicarboxylic acid unit in the polyester resin within the above range.
The polyester resin used in the present invention may further contain an oxycarboxylic acid unit described later.
The polyester resin is an aliphatic polyester resin containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit as a main constituent unit (hereinafter, may be referred to as "aliphatic polyester resin (A)"), an aliphatic polyester resin (A). ) Is a resin in which at least a part of the repeating unit is replaced with an aromatic compound unit. The repeating unit of the aliphatic-aromatic polyester resin (B) and the aliphatic polyester resin (A) is replaced with an aromatic compound unit. The aromatic polyester resin (polyallylate) (C), which is a resin, is preferable, and the aliphatic polyester resin is particularly preferable.

(Aliphatic polyester resin (A))
The aliphatic polyester resin (A), the aliphatic dicarboxylic acid unit an aliphatic diol units and R ² represented by the formula (1) is represented by the above formula is an aliphatic hydrocarbon group (2) described later and an aliphatic dicarboxylic acid unit an aliphatic diol units and R ² represented by the formula (1) is represented by the above formula is an aliphatic hydrocarbon group (2), aliphatic polyester resins containing An aliphatic polyester resin containing an aliphatic oxycarboxylic acid unit represented by the formula (3) is preferable.
Incidentally, the aliphatic diol unit represented by the formula (1), the aliphatic dicarboxylic acid unit wherein R ² is represented by formula (2) is an aliphatic hydrocarbon group is as previously described. Further, the aliphatic polyester resin preferable as the aliphatic polyester (A) is also as described above. The aliphatic oxycarboxylic acid unit represented by the formula (3) and the aliphatic polyester resin (A) are a trifunctional or higher aliphatic polyvalent alcohol and a trifunctional or higher functional aliphatic polyvalent carboxylic acid or an acid thereof. The case where the anhydride or the trifunctional or higher functional aliphatic polyvalent oxycarboxylic acid component is copolymerized will be described later.

As the aliphatic polyester resin (A), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe), and polybutylene succinate aze are used because of their high biodegradability. Polybutylene succinate-based resins such as rate (PBSAz) are particularly preferred, and polybutylene succinate sebacate is most preferred.

(Aliphatic-aromatic polyester resin (B))
The aliphatic-aromatic polyester resin (B) is a resin in which at least a part of the repeating units of the above-mentioned aliphatic polyester resin (A) is replaced with an aromatic compound unit. Aliphatic - aromatic polyester resin (B), an aromatic dicarboxylic acid aliphatic diol units and R ² represented by the above formula (1) is represented by the above formula is an aromatic group (2) Aliphatic-aromatic polyester resin containing a unit; an aliphatic diol unit represented by the formula (1), an aromatic dicarboxylic acid unit represented by the above formula (2) in which ^{R 2 is an aromatic group, and a formula.} An aliphatic-aromatic polyester resin containing an aliphatic oxycarboxylic acid unit represented by (3) is preferable.

Incidentally, the aliphatic diol unit represented by the formula (1), the aromatic dicarboxylic acid unit R ² is represented by formula (2) is an aromatic group are as described above. Further, regarding the aliphatic polyester preferable as the aliphatic-aromatic polyester (B), the aliphatic-aromatic polyester resin (B) is a trifunctional or higher functional aliphatic polyhydric alcohol and a trifunctional or higher functional aliphatic polyvalent carboxylic acid. This is as described above, including the case where an acid or an acid anhydride thereof or a trifunctional or higher functional aliphatic polyvalent oxycarboxylic acid component is copolymerized.

The aliphatic-aromatic polyester resin (B) may contain an aromatic diol unit. That is, the aliphatic-aromatic polyester resin (B) has an aromatic diol unit and an aliphatic dicarboxylic acid unit; an aromatic diol unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit; A diol unit and an aromatic dicarboxylic acid unit; a polyester resin having an aliphatic diol unit, an aromatic diol unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit may be used. Here, specific examples of the aromatic diol component are as described above.

The aliphatic-aromatic polyester resin (B) may contain an aromatic oxycarboxylic acid unit. Specific examples of the aromatic oxycarboxylic acid component that gives the aromatic oxycarboxylic acid unit are as described above.

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.
As the aromatic dicarboxylic acid unit, it is preferable to use a terephthalic acid unit or a 2,5-furandicarboxylic acid unit. Specifically, examples of the aliphatic-aromatic polyester resin (B) include polybutylene adipate terephthalate (PBAT), polybutylene succinate terephthalate (PBST), polybutylene succinate terephthalate (PBSeT), and polybutylene succinate terephthalate (PBSeT). Polybutylene terephthalate resin such as PBAzT), polybutylene adipate furanoate (PBAF), polybutylene succinate furanoate (PBSF), polybutylene succinate furanoate (PBSeF), polybutylene succinate sebacate furanoate (PBSSeF). ) Etc., a polyfuranite carboxylate-based resin is preferable.

As the aliphatic-aromatic polyester resin (B), a resin having succinic acid, adipic acid and sebacic acid as dicarboxylic acid units is preferable. Therefore, as the aliphatic-aromatic polyester resin (B), polybutylene succinate resins such as PBST, PBSF and PBSSeF; polybutylene adipate resins such as PBAT, PBAF and PBASEF and polybutylene such as PBSeT and PBSeF are used. Sebasinate-based resins; polybutylene succinate-based resins such as PBAzT (polybutylene succinate terephthalate) and PBAzF (polybutylene succinate furanoate) are preferable, and polybutylene succinate-aromatic dicarboxylic acids such as PBST, PBSF, and PBSSeF are preferable. Acidic resins are even more preferred.

(Aromatic polyester resin (C))
The aromatic polyester resin (polyarylate) (C) is a resin in which the repeating unit of the above-mentioned aliphatic polyester resin (A) is replaced with an aromatic compound unit.
The aromatic polyester resin (C) is represented by the above formula (2) in which the ^{aromatic diol unit and R 2} which may be contained in the above-mentioned aliphatic-aromatic polyester resin (B) are aromatic groups. Aromatic polyester resin containing an aromatic dicarboxylic acid unit; an aromatic diol unit that may be contained in the aliphatic-aromatic polyester resin (B), represented by the above formula (2) in which ^{R 2 is an aromatic group.} The aromatic dicarboxylic acid unit and the aromatic polyester resin containing the aromatic oxycarboxylic acid unit which may be contained in the aliphatic-aromatic polyester resin (B) are preferable.

The units and the like contained in the aromatic polyester resin (C) are as described above.

(Unit of 3 or more sensuality)
The polyester resin is obtained by copolymerizing a trifunctional or higher functional aliphatic polyvalent alcohol with 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. It may be a resin having an increased melt viscosity. When these copolymerization components are used, one type may be used alone, or two or more types may be used in any combination and ratio.

Specific examples of the trifunctional aliphatic polyhydric alcohol include trimethylolpropane and glycerin. Specific examples of the tetrafunctional aliphatic polyhydric alcohol include pentaerythritol and the like.
Specific examples of the trifunctional aliphatic polyvalent carboxylic acid or its acid anhydride include propanetricarboxylic acid or its acid anhydride. Specific examples of the tetrafunctional polyvalent carboxylic acid or its acid anhydride include cyclopentanetetracarboxylic acid or its acid anhydride.

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 roughly divided into types. Any type can be used, but from the viewpoint of moldability, mechanical strength, appearance of the molded product, etc., (i) a type having two carboxyl groups and one hydroxyl group such as malic acid in the same molecule is preferable. , Malic acid is more preferred.
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 hydroxyls. It is roughly classified into a type in which a group is shared in the same molecule and a type in which (iii) three hydroxyl groups and one carboxyl group are shared in the same molecule. Any type can be used, but those having a plurality of carboxyl groups are preferable, and citric acid and tartaric acid are more preferable. One of these may be used alone, or two or more thereof may be used in any combination and ratio.

When the polyester resin contains a structural unit derived from the above-mentioned trifunctional or higher functional component, the content thereof is preferably 0.01 mol% or more in all the structural units constituting the polyester resin, and on the other hand. 5 mol% or less is preferable, and 2.5 mol% or less is more preferable. The polyester resin does not have to contain the structural units derived from the above-mentioned trifunctional or higher functional components.

(Manufacturing method of polyester resin)
As a method for producing a polyester resin containing a diol unit and a dicarboxylic acid unit, a known method for producing a 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 the diol unit and the dicarboxylic acid component forming the dicarboxylic acid unit are reacted during the production of the polyester resin, the diol component and the dicarboxylic acid so that the produced polyester resin has the desired composition. Adjust the amount of acid component used. 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 mol% to 20 mol more than the dicarboxylic acid component. % Excessive use.

When a component such as an oxycarboxylic acid unit or a polyfunctional component unit is copolymerized with a polyester resin, the compound corresponding to each of the oxycarboxylic acid unit and the polyfunctional component unit so as to have the desired composition. (Monomer or oligomer) may be subjected to the reaction. At this time, there is no limitation on the timing and method of introducing these components into the reaction system, and it is arbitrary as long as the polyester resin can be produced.

For example, in the case of copolymerizing an oxycarboxylic acid with a polyester resin, the time for introducing the oxycarboxylic acid component is not particularly limited as long as it is before the polycondensation reaction between the diol component and the dicarboxylic acid component, and a catalyst is used in advance. Examples thereof include a method of mixing in a state of being dissolved in an oxycarboxylic acid solution, a method of introducing a catalyst into a reaction system at the time of charging a raw material, and a method of 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 or It is preferable to charge the oligomer at the same time in terms of simplification of the process.

Polyester resin is usually manufactured in the presence of a catalyst. As the catalyst, a catalyst that can be used in the production of known polyester resins 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. Among them, tetrapropyl titanate, tetrabutyl titanate and the like are preferable from the viewpoint of 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 weight or more, more preferably 0.001% by weight or more, and usually 3 with respect to the amount of the monomer used. By weight or less, preferably 1.5% by weight or less. By setting the amount of the catalyst within the above range, a sufficient catalytic effect can be obtained while suppressing the production cost, and the coloring or the decrease in hydrolysis resistance of the obtained polymer can be suppressed.

The introduction time of the catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be introduced at the time of raw material preparation 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 forming 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 aliphatic oxycarboxylic acid aqueous solution and introducing it is preferable in terms of increasing the polymerization rate.

Reaction conditions such as temperature, polymerization time, and pressure during the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component are arbitrary as long as the effects of the present invention are not significantly impaired. However, the reaction temperature of the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component is usually 150 ° C. or higher, preferably 180 ° C. or higher, and usually 260 ° C. or lower, preferably 250 ° C. or lower. The reaction atmosphere is usually an inert atmosphere such as nitrogen or argon. The reaction pressure is usually normal pressure to 10 kPa, but normal pressure is particularly preferable. The reaction time is usually 1 hour or more, usually 10 hours or less, preferably 6 hours or less, and more preferably 4 hours or less. By setting the reaction conditions within the above range, gelation due to excessive formation of unsaturated bonds can be suppressed, and the degree of polymerization can be controlled.

The pressure in the polycondensation reaction after the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component is usually 0.01 × 10 ³ Pa or more, preferably 0.03 × 10 ³ Pa or more. , Usually 1.4 × 10 ³ Pa or less, preferably 0.4 × 10 ³ Pa or less. The reaction temperature at this time is usually 150 ° C. or higher, preferably 180 ° C. or higher, and usually 260 ° C. or lower, preferably 250 ° C. or lower. The reaction time is usually 2 hours or more, usually 15 hours or less, preferably 10 hours or less. By setting the reaction conditions within the above range, gelation due to excessive formation of unsaturated bonds can be suppressed, and the degree of polymerization can be controlled.

When producing the polyester resin, 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 mol% or less, preferably 5 mol% or less, more preferably 3 mol% or less, as the ratio of carbonate bond or urethane bond to all the constituent units constituting the polyester resin. be. From the viewpoint of biodegradability of the biodegradable resin composition according to the present embodiment, the carbonate bond is preferably less than 1 mol% and 0.5 mol% or less with respect to all the constituent units constituting the polyester resin. More preferably, it is more preferably 0.1 mol% or less. The urethane bond is preferably 0.55 mol% or less, more preferably 0.3 mol% or less, further preferably 0.12 mol% or less, and 0.05 mol% or less. Is particularly preferable. When this amount is converted to% by weight with respect to the polyester resin composition, it is preferably 0.9% by weight or less, more preferably 0.5% by weight or less, further preferably 0.2% by weight or less, and 0.1% by weight or less. Is particularly preferable. In particular, by setting the urethane bond amount within the above range, smoke generation and odor caused by urethane bond decomposition are suppressed in the film forming process and the like, and film breakage due to foaming in the molten film is suppressed, so that molding is stable. Sex can be ensured. The amount of carbonate bond or urethane bond in the polyester resin can be calculated from the measurement results by NMR (nuclear magnetic resonance spectrum apparatus) such as ¹ H-NMR and ^{13 C-NMR.}

Specific examples of the carbonate compound as a chain extender include diphenyl carbonate, ditril carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, ethylene carbonate, and the like. Examples thereof include diamyl carbonate and dicyclohexyl carbonate. In addition, carbonate 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 using conventionally known techniques. The chain extender is usually added to the reaction system in a uniform molten state without solvent after the completion of polycondensation, and is reacted with the polyester obtained by polycondensation.

More specifically, a polyester resin having a substantially hydroxyl group as a terminal group, which is obtained by catalytically reacting a diol component and a dicarboxylic acid component, is reacted with a chain extender to increase the molecular weight of the polyester. Resin can be obtained. Prepolymers with a weight average molecular weight of 20,000 or more are not affected by the residual catalyst even under harsh conditions such as in a molten state due to the use of a small amount of chain extender, so that gel is not formed during the reaction. A high molecular weight polyester resin 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-mentioned diisocyanate compound as a chain extender, the weight average molecular weight of the prepolymer is preferably 20,000 or more, more preferably 40,000 or more. When the weight average molecular weight is high, the amount of the diisocyanate compound used for increasing the molecular weight can be small, so that the heat resistance is unlikely to decrease. In this way, 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 preferably 0.01 MPa or more, more preferably 0.05 MPa or more, and even more preferably 0.07 MPa or more. On the other hand, the pressure at the time of chain extension is preferably 1 MPa or less, more preferably 0.5 MPa or less, and even more preferably 0.3 MPa or less. The pressure at the time of chain extension is most preferably normal pressure.

The reaction temperature at the time of chain extension is preferably 100 ° C. or higher, more preferably 150 ° C. or higher, further preferably 190 ° C. or higher, and particularly preferably 200 ° C. or higher. On the other hand, the reaction temperature at the time of chain extension is preferably 250 ° C. or lower, more preferably 240 ° C. or lower, and even more preferably 230 ° C. or lower. By keeping the reaction temperature within the above range, the reaction solution is maintained at an appropriate viscosity, so that a uniform reaction is possible, the reaction solution can be sufficiently agitated without requiring high stirring power, and the reaction solution can be sufficiently agitated. It is possible to suppress the coexistence of gelation or decomposition of the polyester resin.

The time for carrying out the chain extension reaction is preferably 0.1 minutes or longer, more preferably 1 minute or longer, and even more preferably 5 minutes or longer. On the other hand, the time for carrying out the chain extension reaction is preferably 5 hours or less, more preferably 1 hour or less, further preferably 30 minutes or less, and particularly preferably 15 minutes or less. By setting the chain extension time within the above range, the chain can be extended to a desired molecular weight, and the coexistence of gelation or decomposition of the polyester resin can be suppressed.
<Resin containing oxycarboxylic acid unit>
The polyester resin containing the oxycarboxylic acid unit will be described in detail.
The oxycarboxylic acid unit contained in the polyester resin is preferably an aliphatic oxycarboxylic acid unit represented by the following general formula (3).
-OR ^3- CO- (3)
In formula (3), R ³ represents an aliphatic hydrocarbon group having 1 or more carbon atoms and 20 or less carbon atoms.

The ^{number of carbon atoms of the aliphatic hydrocarbon group represented by R 3} is preferably 1 or more, more preferably 2 or more, and particularly preferably 5 or more. On the other hand, it is preferably 16 or less, more preferably 12 or less, and further preferably 8 or less.

The aliphatic oxycarboxylic acid component that gives the aliphatic oxycarboxylic acid unit represented by the formula (3) is not particularly limited, and is, for example, glycolic acid, 3-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-. Hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, 3-hydroxypropionic acid, 4-hydroxybutyric acid, 5- Examples thereof include hydroxy acids such as hydroxyvaleric acid and 6-hydroxycaproic acid, or derivatives such as lower alkyl esters or intramolecular esters thereof. When optical isomers are present in these, either D-form or L-form may be used. Of these, glycolic acid and 3-hydroxybutyric acid are preferred.

When the polyester resin contains these aliphatic oxycarboxylic acid units, the content thereof is preferably 20 mol% or less, more preferably 20 mol% or less, based on all the constituent units constituting the polyester resin from the viewpoint of moldability. Is 10 mol% or less, more preferably 5 mol% or less. The polyester resin does not have to contain oxycarboxylic acid.

The oxycarboxylic acid unit contained in the polyester resin may contain an aromatic oxycarboxylic acid unit.
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 the aromatic oxycarboxylic acid compound. Further, it may be a compound (oligomer) having a structure in which a plurality of aromatic 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.

(Aliphatic oxycarboxylic acid resin (D))
As the resin contained in the biodegradable resin composition according to the present embodiment, an aliphatic oxycarboxylic acid resin is also preferably used. The aliphatic oxycarboxylic acid resin (D) contains an aliphatic oxycarboxylic acid unit as a main constituent unit. Examples of the aliphatic oxycarboxylic acid resin (D) include an aliphatic oxycarboxylic acid resin containing an aliphatic oxycarboxylic acid unit represented by the above formula (3).

The aliphatic oxycarboxylic acid unit and the component giving the unit in the aliphatic oxycarboxylic acid resin (D) are the same as the aliphatic oxycarboxylic acid unit and the aliphatic oxycarboxylic acid component in the above-mentioned aliphatic polyester resin (A). The same applies to the preferred embodiment defined in.

Specifically, as the aliphatic oxycarboxylic acid resin (D), polycaprolactone (PCL) and poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) are preferable, and polycaprolactone is more preferable. preferable.

Further, a urethane bond, an amide bond, a carbonate bond, an ether bond or the like may be introduced into the aliphatic oxycarboxylic acid resin (D) as long as it does not affect the biodegradability.

The method for producing the aliphatic oxycarboxylic acid resin (D) is not particularly limited, and it 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.

As the aliphatic oxycarboxylic acid resin (D), the polyhydroxyalkanoate (E) described below is preferable.
(Polyhydroxy alkanoate (E))
The polyhydroxyalkanoate (E) preferably used in this embodiment has a general formula: [-CHR-CH _2- CO-O-] (in the formula, R is an alkyl group having 1 to 15 carbon atoms. ) Is an aliphatic polyester containing a repeating unit, 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 (E) preferably contains 80 mol% or more of 3-hydroxybutyrate units as a constituent component, and more preferably 85 mol% or more. Further, the polyhydroxyalkanoate (E) is preferably produced by a microorganism. Specific examples of the polyhydroxy alkanoate (E) include poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin and poly (3-hydroxybutyrate-co-3-hydroxyvalerate-). Co-3-hydroxyhexanoate) Copolymerized 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 (E), a comonomer such as 3-hydroxybutyrate (hereinafter, may be referred to as 3HB) and 3-hydroxyhexanoate copolymerized (hereinafter, may be referred to as 3HH). The composition ratio of 3-hydroxybutyrate / comonomer is preferably 97/3 or more, that is, the molar ratio of the monomer in the copolymer resin is 97/3 or more from the viewpoint of molding processability, molded product quality, and the like. It is more preferably / 5 or more, and on the other hand, it is preferably 80/20 or less, and more preferably 85/15. By setting the monomer ratio within the above range, the difference between the molding processing temperature and the thermal decomposition temperature becomes large, so that the molding process becomes easy, the crystallization rate becomes an appropriate range, and productivity can be ensured. can.

The ratio of each monomer in the polyhydroxy alkanoate (E) can be measured by gas chromatography as follows.
20 mg of dried polyhydroxyalkanoate is placed in a sample container, 2 ml of sulfuric acid / methanol mixed solution (15/85 (weight ratio)) and 2 ml of chloroform are added thereto, the mixture is sealed, and heated at 100 ° C. for 140 minutes. Then, the polyhydroxyalkanoate is decomposed to obtain a methyl ester. 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 thoroughly, the ratio of each monomer in the copolymer resin can be determined by analyzing the monomer unit composition of the sample decomposition product in the supernatant by capillary gas chromatography. can.

Polyhydroxyalkanoate (E) is, for example, Alcaligenes europhos AC32 strain (international deposit based on the Budapest Treaty, international deposit authority: Independent Administrative Institution Industrial Technology General Institute Patent Organism Deposit Center (1-1-1, Higashi, Ibaraki-shi, Japan, Central 6), Hara Deposit date: Transferred on August 12, 1996, August 7, 1997, Deposit number FERM BP- It can be produced by microorganisms such as 6038 (transferred from the original deposit FERM P-15786)) (J. Bacteriol., 179, 4821 (1997)).

As the polyhydroxy alkanoate (E), a commercially available product can also be used. Commercially available products of polyhydroxyalkanoate (E) containing 3-hydroxybutyrate unit and 3-hydroxyhexanoate unit as main constituent units include "PHBH X331N", "PHBH X131A", and "PHBH X151A" manufactured by Kaneka Corporation. , "PHBH 151C" etc. can be used

In the present embodiment, the aliphatic oxycarboxylic acid resin (D) including the above-mentioned polyhydroxyalkanoate (E) is not limited to one type, but the type of the constituent unit, the constituent unit ratio, the production method, the physical properties, and the like are different. Two or more kinds of aliphatic oxycarboxylic acid resins (D) can be blended and used.

As described above, the polyester resin contained in the biodegradable resin composition according to the present embodiment includes a diol unit represented by the general formula (1) and a dicarboxylic acid unit represented by the general formula (2). Polyester resin containing the above; diol unit represented by the general formula (1), dicarboxylic acid unit represented by the general formula (2), and oxycarboxylic acid unit represented by the general formula (3). A polyester resin or the like containing an oxycarboxylic acid unit represented by the above general formula (3) is preferable.

As the polyester resin contained in the biodegradable resin composition according to the present embodiment, one type may be used alone or two or more types may be used in any combination and ratio as each structural unit. Further, the diol unit, the dicarboxylic acid unit and the aliphatic oxycarboxylic acid unit may be derived from a compound derived from petroleum or a compound derived from a plant material, but are derived from a plant material. It is desirable that it is derived from a compound because it can consider environmental problems.

If an optical isomer is present in the aromatic compound component that gives these aromatic compound units, any of the D-form, L-form, and 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. One type of aromatic compound component may be used alone, or two or more types may be used in any combination and ratio.

(Other resins)
The biodegradable resin composition according to the present embodiment may contain a resin other than the polyester resin.
The other resin is not particularly limited, and a known resin can be used. For example, polyurethane resin; polyimide resin; polyacrylic resin; acrylonitrile-butadiene-styrene resin; acrylonitrile-styrene resin; polycarbonate resin; LDPE, MDPE, HDPE, LLDPE, carboxyl-modified polyethylene and other polyethylene, polypropylene, polybutene, polypentene, ethylene- Polyolefin resins such as propylene copolymers and ethylene-butylene copolymers; polyvinyl acetate resin; polyvinyl chloride resin; polyvinylidene chloride resin; polystyrene resin; epoxy resin; melamine resin; nylon 6, nylon 11, nylon 66, nylon 12. Polyamide resin such as nylon 610 and nylon 6T can be mentioned. These resins may be of only one type or of two or more types.

When the biodegradable resin composition according to the present embodiment contains other resins, the above-mentioned preferable resin is preferably 5% by weight or more because the biodegradable resin composition is excellent in biodegradability. More preferably, it is 10% by weight or more. The resin contained in the biodegradable resin composition according to the present embodiment is preferably only the above-mentioned preferable resin. However, as described above, if the resin contained in the biodegradable resin composition according to the present embodiment is a resin composition with the above-mentioned polysaccharide containing amino sugar, the biodegradability is improved. The resin is not particularly limited, and a resin made of a resin other than the above-mentioned preferable resin may be used.

<Physical characteristics of resin>
The glass transition temperature (Tg) of the resin according to the present invention is 40 ° C. or lower. When biodegrading a resin, the glass transition temperature is lower than the temperature of the environment in which the resin is placed, such as in the ocean, so that the crystal structure of the resin loosens and the molecular main chain can rotate and vibrate, resulting in biodegradation. Is considered to be easy to proceed. Therefore, the glass transition temperature of the resin is preferably 30 ° C. or lower, more preferably 25 ° C. or lower, and particularly preferably 20 ° C. or lower. The glass transition temperature can be measured by the following method. Put 10 mg of each resin in an aluminum sample container and use it as a measurement sample. Then, using DSC, the temperature is raised from −100 ° C. to 160 ° C. at a rate of 10 ° C./min under a nitrogen atmosphere to obtain a DSC chart. In this chart, the glass transition temperature is obtained from the baseline shift existing on the lower temperature side than the peak showing the melting point. Specifically, the intersection of the contact point between the baseline on the low temperature side and the inflection point is defined as the glass transition temperature.

The reduced viscosity ηsp / c of the resin according to the present invention at 30 ° C. is preferably 0.5 dL / g or more and 4.0 dL / g or less. The reduced viscosity of the resin may be appropriately selected within this range according to the application, processing method, and the like. Specifically, the reducing viscosity of the resin at 30 ° C. is more preferably 0.8 dL / g or more, further preferably 1.0 dL / g or more, and 1.2 dL / g or more. It is particularly preferable, and on the other hand, it is more preferably 3.0 dL / g or less, further preferably 2.5 dL / g or less, and particularly preferably 2.3 dL / g or less.
By setting the reducing viscosity of the resin within the above range, it is possible to secure the mechanical properties when the molded product is processed, and the melt viscosity of the biodegradable resin composition during the molding process is determined by the extruder and injection. Productivity can be ensured by not imposing an excessive load on a molding machine such as a machine.

The reduced viscosity of the resin can usually be measured by the following method. First, the resin is dissolved in a solvent to prepare a resin solution having a concentration of c (g / dL). Next, using a capillary viscometer (Ubbelohde viscometer), the solvent passage time t0 and the resin solution passage time t were measured under the condition of a temperature of 30.0 ° C. ± 0.1 ° C., and based on the following equation (i). The relative viscosity ηrel is calculated. Then, the specific viscosity ηsp is obtained from the relative viscosity ηrel based on the following equation (ii).
ηrel = t / t0 ・・・ (i)
ηsp ＝ ηrel-1 ・・・ (ii)
The reduced viscosity ηsp / c can be obtained by dividing the obtained specific viscosity ηsp by the concentration c (g / dL). Generally, the higher this value, the larger the molecular weight.

The molecular weight of the resin is usually measured by gel permeation chromatography (GPC). From the viewpoint of moldability and mechanical strength, the resin contained in the biodegradable resin composition according to the present embodiment preferably has a weight average molecular weight (Mw) of monodisperse polystyrene as a standard substance in the following range. .. That is, the molecular weight of the resin is preferably 10,000 or more, more preferably 20,000 or more, further preferably 30,000 or more, and particularly preferably 50,000 or more. On the other hand, it is preferably 2,500,000 or less, more preferably 1,000,000 or less, further preferably 800,000 or less, and particularly preferably 600,000 or less. It is more preferably 500,000 or less, and most preferably 400,000 or less.

In particular, the weight average molecular weight (Mw) of the polyhydroxyalkanoate resin is preferably 200,000 or more, more preferably 250,000 or more, and even more preferably 300,000 or more. .. On the other hand, the weight average molecular weight (Mw) of the polyhydroxyalkanoate resin is preferably 2500,000 or less, more preferably 2,000,000 or less, and 1,000,000 or less. Is more preferable.

The melt flow rate (MFR) of the resin can be evaluated based on JIS K 7210 (1999) with a value measured at 190 ° C. and a load of 2.16 kg. The MFR of the resin contained in the biodegradable resin composition according to the present embodiment is preferably in the following range from the viewpoint of moldability and mechanical strength. That is, it is preferably 0.1 g / 10 minutes or more, and more preferably 1 g / 10 minutes or more. On the other hand, the MFR of the resin is preferably 100 g / 10 minutes or less, more preferably 80 g / 10 minutes or less, further preferably 50 g / 10 minutes or less, and 40 g / 10 minutes or less. Is particularly preferable, and 30 g / 10 minutes or less is most preferable. The MFR of the resin can be adjusted by the molecular weight and the like.

Good moldability can be ensured by setting the melting point of the resin within the following range. That is, the melting point of the resin is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, further preferably 75 ° C. or higher, particularly preferably 80 ° C. or higher, and on the other hand, preferably 270 ° C. or lower, more preferably 200 ° C. or lower. Preferably, 160 ° C. or lower is further preferable, 150 ° C. or lower is particularly preferable, 140 ° C. or lower is particularly preferable, and 130 ° C. or lower is most preferable. When the resin has a plurality of melting points, it is preferable that at least one melting point is within the above range.

In particular, the melting point of the polyhydroxyalkanoate resin is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, and on the other hand, 180 ° C. or lower, more preferably 170 ° C. or lower, and particularly less than 160 ° C. preferable.

The tensile elastic modulus of the resin is preferably 10 MPa or more, more preferably 100 MPa or more, still more preferably 180 MPa or more, because good molding processability and impact resistance can be ensured. On the other hand, it is preferably 2500 MPa or less, and more preferably 2000 MPa or less. The tensile elastic modulus can be measured by the following method.
A hot press sheet of each resin is prepared and punched into a No. 8 dumbbell mold to prepare a test piece. Specifically, a surface-released gold frame is placed on a 150 mm × 150 mm PTFE tape, 1.6 g of each resin is measured inside the gold frame, and a 150 mm × 150 mm PTFE is further placed on the metal frame. Place the tape. With each resin sandwiched between the PTFF tapes sandwiched between two iron plates (160 mm x 160 mm, thickness 3 mm), heat press using a hot press machine, and then cool using a cooling press machine. Press to obtain a hot press sheet of 70 mm × 70 mm × thickness 0.2 mm. The hot press temperature is 180 ° C., and the hot press time is preheating for 2 minutes and pressing for 2 minutes. The cooling press temperature is 20 ° C., and the cooling press time is 2 minutes. This hot press sheet is uniaxially elongated at a speed of 50 mm / min, and the initial gradient of the obtained stress-strain curve is obtained as the tensile elastic modulus.

The method for adjusting the melting point and tensile elastic modulus of the resin is not particularly limited. It can be adjusted according to the type of copolymerization component and its copolymerization ratio.
The acid value of the resin is preferably low from the viewpoint that hydrolysis is less likely to occur and storage stability is excellent. Therefore, specifically, it is preferably 250 eq / t or less, more preferably 150 eq / t or less, further preferably 100 eq / t or less, and particularly preferably 50 eq / t or less. The acid value can be measured by the following method.
0.4 g of the resin is precisely weighed, 25 mL of benzyl alcohol is added thereto, and the resin is dissolved by heating to 195 ° C. and stirring. When the resin has melted, the container containing the resin solution is cooled in an ice bath, and 2 mL of ethanol is added into the container. Titration is performed using a benzyl alcohol solution of 0.01 N sodium hydroxide (the titration amount is A (ml)).
Next, the same measurement is performed only with benzyl alcohol to obtain a blank value (B (ml)). The acid value is calculated from the following formula.
Terminal acid value (μeq / g) = (AB) × F × 10 / W
A (ml): Measurement titer B (ml): Blank titration F: 0.01N NaOH benzyl alcohol Your phase factor W (g): Sample weight

[Other ingredients]
The biodegradable resin composition according to the present embodiment is a filler (filler), a plasticizer, an antistatic agent, an antioxidant, a light stabilizer, an ultraviolet absorber, as long as the effects of the present invention are not significantly impaired. Dyes, pigments, antioxidants, crystal nucleating agents, anti-blocking agents, weathering agents, heat stabilizers, flame retardants, mold release agents, antifogging agents, surface wetting improvers, incineration aids, dispersion aids, various interfaces It may contain other components such as various additives such as activators, slip agents, freshness preservatives and antibacterial agents. When these components are contained, the components may contain only one type or two or more types.

When the biodegradable resin composition contains other components, the content thereof is 40% by weight or less based on the total amount of the biodegradable resin composition from the viewpoint of not impairing the characteristics of the biodegradable resin composition. It is preferably 20% by weight or less, more preferably 10% by weight or less, and particularly preferably 5% by weight or less. The lower limit of the content of other components is not particularly limited.

[Manufacturing method of biodegradable resin composition]
The method for producing the biodegradable resin composition according to the present embodiment is not particularly limited. The biodegradable resin composition according to the present embodiment can be obtained by kneading a resin, a polysaccharide containing an amino sugar, and if necessary, another resin and other components. The biodegradable resin composition is produced, for example, by blending each component at a predetermined ratio at the same time or in an arbitrary order, and using a machine such as a tumbler, a V-type blender, a Nauter mixer, a Banbury mixer, a kneading roll, or an extruder. It can be carried out by mixing or kneading, preferably by melt-kneading. Alternatively, it can also be produced by dissolving or dispersing a resin and a polysaccharide containing an amino sugar in a solvent and removing the solvent.

From the viewpoint of improving the degree of biodegradation and the biodegradation rate of the biodegradable resin composition, particularly the initial biodegradation rate, it is necessary that polysaccharides including amino sugars are uniformly dispersed in the biodegradable resin composition. preferable. Therefore, the biodegradable resin composition is preferably produced by kneading, and more preferably by melt kneading.

The kneader used for kneading 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.

When melt-kneading is performed, the melt-kneading temperature is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and on the other hand, preferably 220 ° C. or lower, more preferably 210 ° C. or lower. Within this temperature range, melt-kneading can be performed in a short time, deterioration of the color tone due to deterioration of the resin and carbonization of polysaccharides including amino sugars is unlikely to occur, and practical use such as impact resistance and moisture heat resistance. It tends to be a resin composition having better physical characteristics on the surface.
The melt-kneading time is not particularly limited as long as the polysaccharide containing amino sugar can be uniformly dispersed in the biodegradable resin, but similarly, deterioration of the resin is unlikely to occur, so that it is desirable to carry out the melt-kneading time in a short time. Specifically, the melt-kneading time is preferably 10 seconds or more, more preferably 30 seconds or more, and on the other hand, preferably 20 minutes or less, more preferably 15 minutes or less.

[Biodegradability of biodegradable resin composition]
The biodegradable resin composition according to the present embodiment has biodegradability. The resin composition of the present invention is particularly preferably biodegradable in seawater, where the resin is difficult to biodegrade (ocean biodegradable resin composition). The reason why the resin composition of the present invention exhibits biodegradability even in seawater is presumed as follows. Usually, in seawater, the amount and type of microorganisms are small. Therefore, it is difficult for molds and the like to grow in seawater, and it is presumed that the formation of a biofilm is important for biodegradation in seawater. Furthermore, in seawater, nitrogen, which is an essential element for life support, is scarce. Therefore, it is presumed that the presence of polysaccharides including amino sugars promotes cell proliferation and activation of microorganisms in seawater, promotes biofilm formation, and promotes biodegradability.
Further, in the resin, the molecular chain tends to move when the temperature becomes higher than the glass transition temperature. Therefore, it is presumed that a resin having a low glass transition temperature is easily biodegraded. In particular, when the glass transition temperature of the resin is 40 ° C. or lower, it is considered that the resin is more easily biodegraded by polysaccharides containing amino sugars in seawater.
In the present specification, the degree of biodegradation is calculated as the ratio of the biological oxygen demand (BOD) to the theoretical oxygen demand (ThOD).
For example, biodegradation in seawater was measured in accordance with ISO 14851: 1999 (Plastic-How to determine the ultimate aerobic biodegradability in aquatic culture solution-Method by measuring the amount of carbon dioxide generated); Regarding biodegradation in soil, it complies with ISO 17556: 2003 (Plastic-How to determine the aerobic ultimate biodegradability in soil by measuring oxygen consumption or carbon dioxide generated using a respiratory meter). Be measured.
The biodegradable resin composition according to the present embodiment has a degree of biodegradation at an arbitrary time point after the start of the biodegradability test, excluding the above-mentioned polysaccharides containing aminosaccharides from the biodegradable resin composition according to the present embodiment. It is preferable that the degree of biodegradation of the composition (hereinafter, may be referred to as “reference composition”) exceeds 1.0 times (hereinafter, the rate of increase in the degree of biodegradation with respect to the degree of biodegradation of the reference composition). Sometimes referred to as "biodegradation improvement"). Specifically, on the 28th day after the start of the biodegradability test conforming to the above standard, the degree of improvement in biodegradation of the biodegradable resin composition according to the present embodiment is more preferably 1.1 times or more. , 1.2 times or more, more preferably 2.0 times or more, and most preferably 2.5 times or more.
In the present specification, a high degree of biodegradation means that the degree of improvement in biodegradation of the biodegradable resin composition at an arbitrary time after the start of the biodegradability test is the above-mentioned preferable degree of improvement.

[Reducing viscosity of biodegradable resin composition]
The reduced viscosity ηsp / c of the resin composition according to the present embodiment at 30 ° C. is preferably 0.5 dL / g or more and 4.0 dL / g or less. The reduced viscosity of the resin composition may be appropriately selected within this range according to the application, processing method and the like. Specifically, the reducing viscosity of the resin composition at 30 ° C. is preferably 0.8 dL / g or more, more preferably 1.0 dL / g or more, and 1.2 dL / g or more. On the other hand, it is more preferably 3.0 dL / g or less, further preferably 2.5 dL / g or less, and particularly preferably 2.3 dL / g or less.
By setting the reducing viscosity of the resin composition within the above range, it is possible to secure the mechanical properties when the molded product is processed, and the melt viscosity during the molding process is a molding machine such as an extruder or an injection machine. It is possible to secure productivity by not applying an excessive load to the plastic.

[Biodegradation method of polyester resin]
As described above, since the biodegradation of the resin having a glass transition temperature of 40 ° C. or lower can be promoted by the polysaccharide containing aminosaccharide, the biodegradable resin composition according to the present embodiment can be used as a method for biodegrading the resin. Can be applied. Further, since the biodegradation of the polyester resin in seawater can be promoted in particular, the biodegradable resin composition according to the present embodiment can be applied to the biodegradation method of the polyester resin. That is, it can be applied to a method of biodegrading a polyester resin in seawater in the presence of a polysaccharide containing an amino sugar. Here, the polyester resin suitable for this method, polysaccharides containing amino sugars, and the like are as described above.

[Molded product]
The biodegradable resin composition according to the present embodiment 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, co-extrusion molding (film molding by inflation method or 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, vacuum molding, Pneumatic molding), plastic processing, powder molding (rotary molding), various non-woven molding (dry method, bonding method, entanglement method, spunbond method, etc.) and the like. Among them, injection molding, extrusion molding, compression molding or hot press molding is preferably applied, and injection molding or extrusion molding is more preferably applied. As a specific shape, it is preferably applied to a sheet, a film, and a container.

Further, the molded body formed by molding the biodegradable resin composition according to the present embodiment has a chemical function, an electrical function, a magnetic function, a mechanical function, a friction / wear / lubrication function, and an optical function. It is also possible to perform various secondary processes for the purpose of imparting thermal functions, surface functions such as biocompatibility, and the like. Examples of secondary processing include embossing, painting, bonding, 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.

[Use]
The biodegradable resin composition according to the present embodiment is used in a wide range of applications such as packaging materials for packaging various foods, chemicals, liquids such as miscellaneous goods, powders and solids, agricultural materials, and building materials. It is preferably used. Specific applications include injection molded products (eg, fresh food trays, fast food containers, coffee capsule containers, cutlery, outdoor leisure products, etc.), extruded molded products (eg, films, sheets, fishing threads, fishing nets, vegetation, etc.). Examples include nets, secondary processing sheets, water retention sheets, etc.), hollow molded bodies (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. The molded product is particularly suitable as a container for food such as a film for food packaging, a tray for fresh food, a container for fast food, and a lunch box.

Hereinafter, the contents of the present invention will be described in more detail with reference to Examples and Comparative Examples. 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 or 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.

<Synthesis of resin>
(Synthesis of PBSSe)
1,4-Butanediol (100.1 g), succinic acid (75.0 g), sebacic acid (32.1 g), trimethylolpropane (0.34 g) and titanium tetrabutoxide (0.50 g) under nitrogen. It was heated at 200 ° C. for 2 hours with stirring. Subsequently, the temperature was raised to 250 ° C. while reducing the pressure, and the polymer obtained by reacting for 5 hours and 15 minutes was extracted into water in the form of strands and cut to obtain pelletized PBSSe.
¹ The molar ratio of succinic acid-derived units / sebacic acid-derived units of PBSSe determined by 1 H-NMR (Nuclear Magnetic Resonance Spectrum Device) was 80/20. The reducing viscosity of PBSSe measured according to the following measuring method was 2.05 dL / g, the glass transition temperature was −50 ° C., the tensile elastic modulus was 280 MPa, and the acid value was 28 μeq / g.

(Synthesis of PBSeT)
1,4-Butanediol (83.8 g), sebacic acid (75.24 g), terephthalic acid (41.2 g), trimethylolpropane (0.27 g) and titanium tetrabutoxide (0.53 g) under nitrogen. It was heated at 220 ° C. for 2 hours with stirring. Subsequently, the temperature was raised to 240 ° C. while reducing the pressure, and the polymer obtained by reacting for 3 hours and 15 minutes was extracted into water in the form of strands and cut to obtain pellet-shaped PBSeT. The molar ratio of the sebacic acid-derived unit / terephthalic acid-derived unit of PBSeT determined by ^{1 H-NMR (Nuclear Magnetic Resonance Spectrum) was 60/40.} Further, when the reducing viscosity of PBSeT was measured according to the following measuring method, it was 1.41 dL / g, the glass transition temperature was −45 ° C., the tensile elastic modulus was 30 MPa, and the acid value was 28 μeq / g. ..

<Commercial resin>
(PCL)
PCL manufactured by Sigma-Aldrich. The reduction viscosity is 1.28 dL / g, the glass transition temperature is -60 ° C, and the tensile elastic modulus is 430 MPa.
(PHBH)
PHBH "151C" manufactured by Kaneka Corporation. The glass transition temperature is 0 ° C. (catalog value), and the tensile elastic modulus is 950 MPa.
(PLA)
PLA "4032D" manufactured by Nature Works. The glass transition temperature is 55-60 ° C. (catalog value), the reducing viscosity is 2.18 dL / g, and the tensile elastic modulus is 3450 MPa.

(Measurement method of glass transition temperature)
10 mg of each resin was placed in an aluminum sample container to prepare a measurement sample. Next, using "DSC6220" manufactured by Hitachi High-Tech Science Corporation, the temperature was raised from −100 ° C. to 160 ° C. at a rate of 10 ° C./min under a nitrogen atmosphere to obtain a DSC chart. In this chart, the glass transition temperature was obtained from the baseline shift existing on the lower temperature side than the peak showing the melting point. Specifically, the intersection of the contact point between the baseline on the low temperature side and the inflection point was defined as the glass transition temperature.

(Measuring method of reduced viscosity)
Each resin was dissolved in a 1: 1 (weight ratio) mixed solvent of phenol and tetrachloroethane so as to be 0.5 g / dL to prepare a resin solution. Next, using a Ubbelohde viscous tube, the passage time of the resin solution at 30 ° C. was measured, and the reduced viscosity was calculated based on the result.

(Measuring method of tensile elastic modulus)
A hot press sheet of each resin was prepared and punched into a No. 8 dumbbell mold to prepare a test piece. Specifically, a gold frame (SUS304, outer diameter) that has been surface-demolded on a 150 mm × 150 mm PTFE tape (Nachias Corporation Naflon tape (registered trademark) BTOMBO No. 9001, thickness 0.05 mm). (110 mm, inner diameter 70 mm, thickness 0.2 mm) was placed, 1.6 g of each resin was weighed inside the metal frame, and a 150 mm × 150 mm PTFE tape was further placed on it. Using a heat press machine (“IMC-180C type” manufactured by Imoto Seisakusho Co., Ltd.) with each resin sandwiched between the PTFF tapes sandwiched between two iron plates (160 mm × 160 mm, thickness 3 mm). The heat press was performed, and then the cooling press was performed using a cooling press machine (“IMC-181B type” manufactured by Imoto Seisakusho Co., Ltd.) to obtain a heat press sheet having a thickness of 70 mm × 70 mm × thickness 0.2 mm. The hot press temperature was 180 ° C., and the hot press time was preheating for 2 minutes and pressing for 2 minutes. The cooling press temperature was 20 ° C., and the cooling press time was 2 minutes. This hot press sheet was uniaxially elongated at a speed of 50 mm / min using "STB-1225L" manufactured by Orientec, and the initial gradient of the obtained stress-strain curve was determined as the tensile elastic modulus.

(Measuring method of acid value)
0.4 g of the resin was precisely weighed, 25 mL of benzyl alcohol was added thereto, and the resin was dissolved by heating to 195 ° C. and stirring. When the resin was dissolved, the container containing the resin solution was cooled in an ice bath, and 2 mL of ethanol was added into the container. Titration was performed using an automatic low device "GT100" manufactured by Mitsubishi Chemical Corporation using a benzyl alcohol solution of 0.01 N sodium hydroxide (the titration amount is A (ml)).
Next, the same measurement was carried out using only benzyl alcohol to obtain a blank value (B (ml)). The acid value was calculated from the following formula.
Terminal acid value (μeq / g) = (AB) × F × 10 / W
A (ml): Measurement titer B (ml): Blank titration F: 0.01N NaOH benzyl alcohol Your phase factor W (g): Sample weight

<Example 1>
PBSSe: Chitin (manufactured by Tokyo Chemical Industry Co., Ltd.) is blended at a weight ratio of 90:10, put into a small twin-screw kneader (“Xplore MC15 Micro Composer” manufactured by DSM), and melted at 150 ° C. for 3 minutes in a nitrogen atmosphere. Kneaded. The obtained kneaded product was pulverized, and particles having a particle size of 250 μm or less were classified to obtain a biodegradable resin composition having a chitin content of 10% by weight.

<Example 2>
In Example 1, heparin sodium (manufactured by Nacalai Tesque) was used instead of chitin to obtain a biodegradable resin composition having a heparin sodium content of 10% by weight and a particle size of 250 μm or less, as in Example 1. ..

<Example 3>
In Example 1, using sodium chondroitin sulfate (manufactured by Nacalai Tesque) instead of chitin, a biodegradable resin composition having a chondroitin sulfate C sodium content of 10% by weight and a particle size of 250 μm or less was used in the same manner as in Example 1. I got something.

<Example 4>
In Example 1, sodium hyaluronate (manufactured by Nacalai Tesque, Inc.) was used instead of chitin to prepare a biodegradable resin composition having a sodium hyaluronate content of 10% by weight and a particle size of 250 μm or less, as in Example 1. Obtained.

<Comparative example 1>
PBSSe was pulverized, and particles having a particle size of 250 μm or less were classified to obtain a sample.

<Comparative example 2>
In Example 1, cellulose (manufactured by Sigma-Aldrich) was used instead of chitin to obtain a biodegradable resin composition having a cellulose content of 10% by weight and a particle size of 250 μm or less, as in Example 1.

<Example 5>
PBSeT and chitin were each pulverized and classified into powders having a particle size of 250 μm or less. 27 mg of PBSeT powder and 3 mg of chitin powder were weighed and placed in a 510 mL brown bottle.

<Comparative example 3>
30 m of PBSeT powder was weighed and placed in a 510 mL brown bottle.

<Example 6>
The PCL was pulverized and classified into 250 μm or less into a powder. 27 mg of PCL powder and 3 mg of chitin powder were weighed and placed in a 510 mL brown bottle.

<Comparative example 4>
30 mg of PCL powder was weighed and placed in a 510 mL brown bottle.

<Example 7>
PHBH was pulverized and classified into 250 μm or less into a powder. 27 mg of PHBH powder and 3 mg of chitin powder were weighed and placed in a 510 mL brown bottle.

<Comparative example 5>
30 mg of PHBH powder was weighed and placed in a 510 mL brown bottle.

<Comparative Example 6>
The PLA was pulverized and classified into 250 μm or less into a powder. 27 mg of PLA powder and 3 mg of chitin powder were weighed and placed in a 510 mL brown bottle.

<Comparative Example 7>
A 30 mg powder sample of PLA was weighed and placed in a 510 mL brown bottle.

<Biodegradability test>
The degree of biodegradation of the samples obtained in Examples 1 to 7 and Comparative Examples 1 to 7 was measured as follows by a method based on ISO 14851.
To a 510 mL brown bottle containing 30 mg of the sample, 100 mL of a mixture of standard test culture solution and seawater prepared by a method conforming to ISO 14851 was added. A pressure sensor (WTW, OxiTop®-C type) was attached to the brown bottle, and the temperature was constant at 25 ° C. for a predetermined period (Examples 1 to 7 and Comparative Examples 1 to 5 were 28 days, Comparative Example. The test solution was stirred with a stirrer (for 42 days for 6 and 7), and the degree of biodegradation (%) was calculated based on the BOD measurement. The results are shown in Table 1.

* 1 Magnification of biodegradation of the sample of Comparative Example 1 with respect to 1.0 biodegradation * 2 Magnification of biodegradation of sample of Comparative Example 3 with respect to 1.0 biodegradation * 3 Biodegradation of sample of Comparative Example 4 Magnification of biodegradation degree with respect to degree 1.0 * 4 Magnification of biodegradation degree with respect to biodegradation degree 1.0 of sample of Comparative Example 5 * 5 Magnification of biodegradation degree with respect to biodegradation degree 1.0 of sample of Comparative Example 7

From Table 1, when 28 days have passed since the start of the biodegradability test, the biodegradable resin compositions (Examples 1 to 7) containing the resin and the polysaccharide containing aminosaccharides are the resin itself (Comparative Example 1, It was confirmed that the degree of biodegradation was more than twice that of 3 to 5).
On the other hand, the composition containing the resin and cellulose (Comparative Example 2) improved the degree of biodegradation only 1.04 times as much as that of the resin itself.
In addition, for resins with a glass transition point higher than 40 ° C, the degree of biodegradation may rather decrease by using polysaccharides containing amino sugars, even though the biodegradability test has been conducted for a long period of time. found.
From these results, it was confirmed that the degree of biodegradation of the resin having a glass transition temperature of 40 ° C. or lower was significantly improved by the polysaccharide containing amino sugar.

Claims

A biodegradable resin composition containing a resin having a glass transition temperature of 40 ° C. or lower and a polysaccharide containing an amino sugar, wherein the content of the polysaccharide containing an amino sugar is 0.01% by weight or more and 30% by weight. The following biodegradable resin composition.
The biodegradable resin composition according to claim 1, wherein the resin is a polyester resin.
The biodegradable resin composition according to claim 2, wherein the polyester resin has at least one selected from the group consisting of 1,4-butanediol, 1,3-propanediol and ethylene glycol as a diol unit.
The biodegradable resin composition according to claim 2 or 3, wherein the polyester resin has a dicarboxylic acid having 2 to 22 carbon atoms as a dicarboxylic acid unit.
The biodegradable resin composition according to any one of claims 1 to 4, wherein the resin is a biodegradable resin.
The biodegradable resin composition according to any one of claims 2 to 5, wherein the polyester resin has a tensile elastic modulus of 10 to 2500 MPa.
The biodegradable resin composition according to any one of claims 1 to 6, wherein the polysaccharide is a polysaccharide containing glucosamines.
The biodegradable resin composition according to claim 7, wherein the polysaccharide is chitin.
A molded product containing the biodegradable resin composition according to any one of claims 1 to 8.
A method for biodegrading a polyester resin, which comprises biodegrading a polyester resin having a glass transition temperature of 40 ° C. or lower in seawater in the presence of a polysaccharide containing an amino sugar.