JP7056036B2 - Plant protection materials and resin compositions for plant protection materials - Google Patents

Description

The present invention relates to a plant protection material and a resin composition for a plant protection material. More specifically, the present invention relates to a plant protective material comprising a resin composition containing an aliphatic polyester resin, an aromatic aliphatic copolymerized polyester resin, and the like, and a resin composition for that purpose.

In general, the damage caused by wild birds and beasts of forest plants is often caused mainly by deer, bears, rabbits, etc., especially when the plants are young trees and seedlings, rabbits, deer, cows, giraffes, etc. There has been a problem of tree withering and growth inhibition due to feeding damage of plant buds, leaves, bark, etc. by herbivorous animals.

As a method for protecting plants from such feeding damage of wild birds and beasts, for example, Patent Document 1 describes a net or sheet-shaped plant protection material that is wrapped around a tree trunk to prevent feeding damage by animals, and is an aliphatic material. A plant obtained by blending 5 to 100 parts by weight of talc with 100 parts by weight of a polyester resin composition consisting of 100 parts by weight of polyester resin and 1 to 200 parts by weight of polycaprolactone, and molding the polyester resin composition into a net shape. Protective materials are disclosed.

Further, in Patent Document 2, at least a band portion formed of a biodegradable resin into a sheet shape and can be wound around a predetermined position on a tree trunk, and at least a band portion formed of a biodegradable resin, the band portion is described above. Described is a bird / beast damage prevention device provided with a fixing portion capable of fixing the band portion in a tubular shape when wound at a predetermined position on the trunk. In Patent Document 3, a non-rigid, non-rigid, deformable and reconstructable vertical band having an L-shaped cross-sectional shape is provided at the four corners of a square-shaped net cylinder made of a synthetic resin net. The provided net cylinder for preventing animal damage is described.

Japanese Unexamined Patent Publication No. 11-346575 Japanese Patent Application Laid-Open No. 2002-330691 Japanese Unexamined Patent Publication No. 2004-187677

Patent Documents 1 to 3 describe that a biodegradable resin is used as a constituent material of a plant protection material and an animal damage prevention device. It attaches to trees such as young trees to protect them from feeding damage by wild birds and beasts, and protects those plants after the young trees have grown or after they can be attached to trees instead of young trees to protect them from feeding damage. When materials and animal damage prevention equipment are no longer needed, biodegradable resin is decomposed and returned to the soil (it is also decomposed in the soil), so there is no need for manual removal and labor. It depends.

However, in the plant protection materials and animal damage prevention devices made of biodegradable resins described in Patent Documents 1 to 3, biodegradation proceeds due to moisture in the air and the like, and young trees and seedlings grow. There was a problem that the plants could not be protected and decomposed for a sufficient period of time. In addition, during the period in which these protective materials and equipment are stored in a warehouse until they are attached to plants, biodegradation occurs due to moisture, and the shape and physical properties required for protective materials and equipment cannot be maintained (the shape collapses). There was also the problem that it could not be used by attaching it to plants.

Further, a protective material that is processed into a sheet shape or a net shape and used by wrapping it around a tree needs to be a material that can be easily processed into a shape suitable for the usage pattern. In addition, in order to wind it, it is necessary to stretch it as a sheet, and it is also necessary to have appropriate breaking strength so that the sheet will not be cut at the time of attachment and it will not be bitten by animals during use. ..

However, conventional plant protection materials have not been provided that have appropriate biodegradability and are excellent in physical properties such as molding processability, elasticity, and strength in a well-balanced manner.

INDUSTRIAL APPLICABILITY The present invention is a machine that sufficiently protects a plant for a desired period for protecting the plant, has biodegradability that can be decomposed thereafter, can stably maintain its shape and physical properties during storage, and has breaking strength and the like. It is an object of the present invention to provide a plant protective material having excellent strength, elasticity, and moldability, and a resin composition for a plant protective material.

As a result of diligent research to solve the above problems, the present inventor has added the carbodiimide compound (D) to an aliphatic polyester resin (A) containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, and an aliphatic diol. Plant protection comprising a resin composition blended into an aromatic aliphatic copolymerized polyester resin (B) containing a unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit, and a polyester resin (C) containing an aliphatic oxycarboxylic acid unit. It was found that the material can solve the above problem.

That is, the gist of the present invention is the following [1] to [5].

[1] Aliphatic polyester resin (A) containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, an aromatic aliphatic copolymerized polyester resin containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit. A plant protective material comprising (B), a polyester resin (C) containing an aliphatic oxycarboxylic acid unit, and a resin composition containing a carbodiimide compound (D).

[2] The plant protection material according to [1], wherein the carbodiimide compound (D) is a polycarbodiimide compound.

[3] The plant protection material according to [2], wherein the polycarbodiimide compound is an aliphatic polycarbodiimide compound.

[4] 0.1 to 2 of the carbodiimide compound (D) is added to 100 parts by mass of the total of the aliphatic polyester resin (A), the aromatic aliphatic copolymerized polyester resin (B) and the polyester resin (C). The plant protective material according to any one of [1] to [3], which comprises a part by mass.

[5] The plant protective material according to any one of [1] to [4], which is in the form of a net, a cylinder, or a sheet.

[6] The plant protection material according to any one of [1] to [5], which is used by wrapping around a plant.

[7] Aliphatic polyester resin (A) containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, an aromatic aliphatic copolymerized polyester resin containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit. (B), a polyester resin (C) containing an aliphatic oxycarboxylic acid unit, and a resin composition for a plant protective material containing a carbodiimide compound (D).

In the resin composition for a plant protective material according to the present invention, hydrolysis of an aliphatic polyester resin (A), an aromatic aliphatic copolymerized polyester resin (B), and a polyester resin (C), which are biodegradable resins, is carried out. It can be delayed by the carbodiimide compound (D). Therefore, by blending this carbodiimide compound (D), biodegradation is prevented during storage of the plant protection material to maintain stable shape and physical properties, and even after being applied to plants as a plant protection material, The timing of biodegradation can be controlled so that biodegradation is prevented during the desired period for plant protection and then biodegraded when the plant protection material is no longer needed. Further, by blending an aliphatic polyester resin (A), an aromatic aliphatic copolymerized polyester resin (B), a polyester resin (C), and a carbodiimide compound (D), the elasticity and strength required as a plant protection material can be obtained. It is possible to develop physical properties and molding processability in a well-balanced manner.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist thereof.
In the present specification, "% by mass" and "parts by mass" and "% by weight" and "parts by weight" are synonymous with each other.

Further, in the present specification, the "aliphatic diol" means an "aliphatic diol" in a broad sense including "aliphatic diol (chain diol)" and "alicyclic diol (cyclic diol)". Further, "aliphatic dicarboxylic acid" also means "aliphatic dicarboxylic acid" in a broad sense including "aliphatic dicarboxylic acid" and "alicyclic dicarboxylic acid". The same applies to "aliphatic oxycarboxylic acid".

The plant protection material of the present invention includes an aliphatic polyester resin (A) (hereinafter, may be referred to as "component (A)") and a fat, wherein the plant protection material contains an aliphatic diol unit and an aliphatic dicarboxylic acid unit. Aromatic aliphatic copolymerized polyester resin (B) containing a group diol unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit (hereinafter, may be referred to as "component (B)"), an aliphatic oxycarboxylic acid. A polyester resin (C) containing a unit (hereinafter, may be referred to as "aliphatic oxycarboxylic acid-based polyester resin (C)" or "component (C)"), and a carbodiimide compound (D) (hereinafter, "component"). It is characterized by comprising the resin composition for a plant protective material of the present invention containing (D) ”.

A feature of the plant protective material of the present invention is to use a molded product obtained by molding a resin composition containing the above components (A) to (D). Details of the components (A) to (D) will be described later.

The mechanism of biodegradation of the components (A) to (C), which are biodegradable resins typified by polybutylene succinate (PBS), includes hydrolysis, and the presence of water in the soil or air. The terminal carboxyl group of the polymer promotes its decomposition. In the present invention, the component (D) is blended with the components (A) to (C) which are biodegradable resins. The component (D) is a component that makes it difficult for the biodegradable resin to be hydrolyzed, and the mechanism is that the component (D) partially protects the terminal carboxyl group of the resin such as the component (A). By preventing contact between the carboxyl group and water and preventing hydrolysis. As a result, the time until biodegradation and the decrease in molecular weight due to biodegradation are delayed, and as a result, the molecular weights of the resins of the components (A) to (C) are maintained, and the shape and physical properties can be maintained. become able to.
However, if too much component (D) is added, biodegradation will not proceed easily. Therefore, it is necessary to control the blending amount of component (D) according to the desired time of biodegradation and the degree to which biodegradation should be delayed. .. Further, when the component (D) is added, the fluidity (MFR) of the resin composition is also lowered, so that the stability of the bubble and the neck-in are improved and the molding becomes easier. The pressure becomes high and it becomes difficult to mold. From this viewpoint as well, a suitable blending ratio of the component (D) is set.
Generally, the biodegradability required for a resin composition for a plant protection material is, for example, if a young tree can grow without being damaged by feeding and can be protected until it becomes an adult tree, then it is biodegraded and in the soil. Decomposition is desired, and an appropriate amount of the component (D) is designed from the balance between the rate of biodegradation and moldability.

Examples of the shape of the plant protective material of the present invention include a net shape, a tubular shape, and a sheet shape. Here, the sheet includes a mesh-like sheet with holes (mesh sheet). Moreover, the plant protection material of the present invention may be in the form of a grid.
The plant protection material of the present invention is usually used by wrapping it around a plant, but it may also be used by being attached around the plant so as to surround the plant. It may also be used by covering plants.

The net is made by combining fibers vertically and horizontally and fixing them. The warp and weft may be fixed by weaving, or by bonding or fusing the warp and weft. The suitable thickness, width, and height of the net are the same as those of the sheets described below. The thickness of the fibers or fiber bundles that make up the net depends on the plant to which the plant protection material is applied, the type of wild birds and beasts that cause damage, the usage environment (wind strength, etc.), etc., but 100 to 10,000 denier is preferable. .. The net mesh is preferably 0.1 to 100 mm. The net may be wrapped directly around the trunk of the tree, or it may be fixed to a support around the tree and attached like a fence.

The tubular plant protection material has a thickness of usually 0.1 to 10 mm, preferably 0.3 to 5 mm, and the length and width are not particularly limited, and the width is wide according to the size of the plant to be applied. It is cut from a long object, or a certain standard is formed and a plurality of sheets are used to form an object having a desired width and length for use. The tubular plant protection material is not limited to a cylindrical shape, but may be processed into a square tubular shape with creases at four points and a square cross section, and a hole is made in the surface to ensure breathability. However, a fastener may be provided so that it can be fixed to the attachment rod at the time of installation. The tubular plant protection material is used, for example, by covering a young tree from above and fixing it with a splint.

The thickness of the sheet is usually 0.1 to 10 mm, preferably 0.3 to 5 mm, and the length and width are not particularly limited, and the sheet is cut from a wide or long object according to the size of the plant to be applied. Or, mold a certain standard and use a plurality of them to form a desired width and length for use. The surface of the sheet can be provided with irregularities in a grid pattern to provide a reinforcing effect. The usage of the sheet is the same as that of the net.

The mesh sheet is obtained by perforating the above sheet or forming it into a perforated sheet. Any shape of the hole such as a circle, a square, or a hexagonal shell can be used. The thickness, length, and width of the mesh sheet are the same as those of the above sheet, and the thickness of the vertical member and the horizontal member constituting the mesh is preferably 0.1 to 10 mm, and the opening is preferably 0.1 to 10 mm. .. The usage of the mesh sheet is the same as that of the sheet.

The grid corresponds to a fence or fence shape as a whole, and the vertical member and the horizontal member of the mesh sheet are rod-shaped or plate-shaped, and is used when strength is required. The thickness or maximum width of the member is preferably 1 to 100 mm, and the opening is preferably 10 to 500 mm. The vertical and horizontal members are fitted, glued or fused at intersections. The grid is manufactured by molding it into a desired shape in advance, molding the constituent unit members into each shape and using them in combination, or molding the vertical and horizontal members, then fitting the intersections, and adhering or fusing them. be able to. The grid can be used to cover the entire plant or to surround fruit trees and the like. The rod or cylindrical grid members pierce the ground around the plant in a fence shape to prevent the invasion of animals, and at the same time, serve as a support to prevent the plant from tilting or tipping over.

As a molding method for the plant protective material, various molding methods such as injection molding, extrusion molding, transfer molding, compression molding, and blow molding can be used. For example, as a method for forming the net, a diamond mesh net method for forming a mandarin orange net or a square mesh net method may be used, or a method of extruding warp and weft from a mold and fusing them may be used. The warp and weft may be knitted and then heat-fused. Further, the thread forming the net may be stretched. Examples of the sheet forming method include T-die extrusion, blowing, calendar forming and the like. In addition, as a method for forming a mesh sheet or a grid, a method such as a plastic basket, a colander, a golf club separator, a planting net or an injection molding applied to a fence can be used.

The plant to which the plant protection material of the present invention is applied is not particularly limited, and may be any tree, grass, field crop, or the like. Plant protection materials are used by wrapping around plant trunks, covering specific parts such as roots, buds, leaves, flowers, and fruits, covering plants in a dome shape, and surrounding plants in a fence shape. can do. In addition, among the plant protection materials, thinly molded ones can be used for controlling the temperature and light rays in the cultivation of plants.

Next, each component contained in the resin composition for a plant protection material of the present invention, which is a constituent material of the plant protection material of the present invention, will be described.

<Alphatic polyester resin (A)>
The aliphatic polyester resin (A) contains an aliphatic diol unit and an aliphatic dicarboxylic acid unit as essential components, and is preferably represented by the following formula (1), the aliphatic diol unit, and the following formula (2). The aliphatic dicarboxylic acid unit is an essential component. The aliphatic polyester resin (A) is distinguished from the aromatic aliphatic copolymerized polyester resin (B) described later by not containing an aromatic dicarboxylic acid unit.
-OR ¹ -O- (1)
-OC-R ² -CO- (2)
(In the above formulas (1) and (2), R ¹ is a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group, and R ² is a directly bonded divalent aliphatic hydrocarbon group. Or it represents a divalent alicyclic hydrocarbon group.)

The aliphatic diol component (a-1) giving the aliphatic diol unit of the formula (1) usually has 2 or more and 10 or less carbon atoms, and is, for example, ethylene glycol, 1,3-propanediol, 1,4. -Butandiol, 1,4-cyclohexanedimethanol and the like can be mentioned, among which ethylene glycol and 1,4-butanediol are preferable, and 1,4-butanediol is particularly preferable.

The aliphatic dicarboxylic acid component (a-2) giving the aliphatic carboxylic acid unit of the formula (2) usually has 2 or more and 10 or less carbon atoms, and is, for example, succinic acid, adipic acid, suberic acid, and sebacic acid. , Dodecanedioic acid and the like, of which succinic acid and adipic acid are preferable.

It should be noted that two or more types of the aliphatic diol component (a-1) and the aliphatic dicarboxylic acid component (a-2) can be used.

Further, two or more kinds of aliphatic polyester resins (A) having different constituent units can be blended and used. Specifically, (a-1) is 1,4-butanediol, (a-2) is an aliphatic polyester resin (A-1) in which succinic acid is used, and (a-1) is 1,4-. Examples thereof include a blend of butanediol, an aliphatic polyester resin (A-2) in which (a-2) is succinic acid and adipic acid.

The aliphatic polyester resin (A) used in the present invention may further contain an aliphatic oxycarboxylic acid unit.

Specific examples of the aliphatic oxycarboxylic acid component that gives the aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 3-hydroxy-n-valeric acid, ε-caprolactone, and 2-hydroxycapron. Examples thereof include acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, and mixtures thereof. Alternatively, these lower alkyl esters and intramolecular esters may be used. Further, when optical isomers are present in these, any of D-form, L-form, and racemic form may be used, and the form may be any of solid, liquid, and aqueous solution. Of these, lactic acid or glycolic acid is preferred. These aliphatic oxycarboxylic acid components can be used alone or as a mixture of two or more kinds.

When the aliphatic polyester resin (A) contains these aliphatic oxycarboxylic acid components, the lower limit of the content exceeds 0 mol% among all the components constituting the aliphatic polyester resin (A), which is preferable. Is 0.01 mol% or more, and the upper limit is usually 30 mol% or less, preferably 20 mol% or less, and more preferably 10 mol% or less.

Further, the aliphatic polyester resin (A) of the present invention is trifunctional or higher, an aliphatic and / or an aliphatic polyhydric alcohol, an aliphatic and / or an alicyclic polyvalent carboxylic acid or an anhydride thereof, or an aliphatic. A polyvalent oxycarboxylic acid may be contained as a copolymerization component, and by containing these trifunctional or higher components, the melt viscosity of the obtained aliphatic polyester resin (A) can be increased, which is preferable. In this case, specific examples of the trifunctional aliphatic or alicyclic polyhydric alcohol include trimethylolpropane, glycerin or an anhydride thereof, and specific examples of the tetrafunctional aliphatic or alicyclic polyhydric alcohol include trifunctional aliphatic or alicyclic polyhydric alcohol. Is pentaerythritol. Specific examples of the trifunctional aliphatic or alicyclic polyvalent carboxylic acid or its anhydride include propantricarboxylic acid or its anhydride, and the tetrafunctional aliphatic or alicyclic polyvalent carboxylic acid or its anhydride thereof. Specific examples of the product include cyclopentanetetracarboxylic acid or an anhydride thereof. The trifunctional aliphatic oxycarboxylic acid component includes (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) one carboxyl group and two hydroxyl groups. It is divided into a type having a group in the same molecule, and any type can be used. Specific examples thereof include type (i) malic acid. The tetrafunctional aliphatic oxycarboxylic acid component is (i) a type having 3 carboxyl groups and 1 hydroxyl group in the same molecule, and (ii) 2 carboxyl groups and 2 hydroxyl groups. It is divided into a type having the above in the same molecule and a type having (iii) three hydroxyl groups and one carboxyl group shared in the same molecule, and any type can be used. Specific examples include citric acid and tartaric acid. These trifunctional or higher components may be used alone or in combination of two or more.

When the aliphatic polyester resin (A) contains these trifunctional or higher components, the lower limit of the content exceeds 0 mol% among all the components constituting the aliphatic polyester resin (A), preferably. It is 0.01 mol% or more, and the upper limit is usually 5 mol% or less, preferably 2.5 mol% or less.

The aliphatic polyester resin (A) used in the present invention can be produced by a known method. For example, when the above-mentioned aliphatic dicarboxylic acid component (a-2) and aliphatic diol component (a-1), as well as an aliphatic oxycarboxylic acid unit or a trifunctional or higher component are introduced, those components are also included. A general method of melt polymerization such as an esterification reaction and / or an ester exchange reaction between a dicarboxylic acid component and a diol component and then a polycondensation reaction under reduced pressure, or a known solution using an organic solvent. Although it can be produced by a heat dehydration condensation method, a melt polymerization method performed without a solvent is preferable from the viewpoint of economy and simplification of the production process.

Further, the polycondensation reaction is preferably carried out in the presence of a polymerization catalyst. The timing of adding the polymerization catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be added at the time of charging the raw materials or at the start of reduced pressure.

Examples of the polymerization catalyst generally include compounds containing Group 1 to Group 14 metal elements excluding hydrogen and carbon in the periodic table. Specifically, at least one metal selected from the group consisting of titanium, zirconium, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, calcium, strontium, sodium and potassium. Examples thereof include compounds containing organic groups such as carboxylates, alkoxy salts, organic sulfonates or β-diketonate salts, and inorganic compounds such as metal oxides and halides described above, and mixtures thereof.

Among these, metal compounds containing titanium, zirconium, germanium, zinc, aluminum, magnesium and calcium, and mixtures thereof are preferable, and among them, titanium compounds and germanium compounds are particularly preferable. Further, the catalyst is preferably a liquid at the time of polymerization, or a compound that is soluble in an ester low polymer or polyester, because the polymerization rate increases when the catalyst is melted or dissolved at the time of polymerization.

When a metal compound is used as the polymerization catalyst, the amount of metal added to the produced polyester is usually 5 ppm or more, preferably 10 ppm or more, and the upper limit is usually 30,000 ppm or less, preferably 1000 ppm or less. It is more preferably 250 ppm or less, and particularly preferably 130 ppm or less. If the amount of catalyst used is too large, not only is it economically disadvantageous, but also the thermal stability of the polymer is low, whereas if it is too small, the polymerization activity is low, and the polymer is decomposed during polymer production. Is more likely to be triggered.

The reaction temperature of the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component has a lower limit of usually 150 ° C. or higher, preferably 180 ° C. or higher, and an upper limit of usually 260 ° C. or lower, preferably 250 ° C. or lower. The reaction atmosphere is usually under the atmosphere of an inert gas such as nitrogen or argon. The reaction pressure is usually normal pressure to 10 kPa, but normal pressure is preferable.

The lower limit of the reaction time is usually 1 hour or more, and the upper limit is usually 10 hours or less, preferably 4 hours or less.

In the polycondensation reaction after the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component, the lower limit is usually 0.01 × 10 ³ Pa or more, preferably 0.01 × 10 ³ Pa or more. Yes, the upper limit is usually 1.4 × 10 ³ Pa or less, preferably 0.4 × 10 ³ Pa or less. At this time, the lower limit of the reaction temperature is usually 150 ° C. or higher, preferably 180 ° C. or higher, and the upper limit is usually 260 ° C. or lower, preferably 250 ° C. or lower. The lower limit of the reaction time is usually 2 hours or more, and the upper limit is usually 15 hours or less, preferably 10 hours or less.

As a reactor for producing the aliphatic polyester resin (A), a known vertical or horizontal stirring tank type reactor can be used. For example, using the same or different reactors, esterification of melt polymerization and / or ester exchange and vacuum polycondensation are performed in two stages. As the reactor for vacuum polycondensation, a vacuum pump and a reactor are used. A method of using a stirring tank type reactor equipped with a decompression exhaust pipe to be connected can be mentioned. Further, a method of connecting a condenser between the vacuum pump and the decompression exhaust pipe connecting the reactor and recovering the volatile components and unreacted monomers generated during the polycondensation reaction in the condenser is preferably used. Be done.

In the present invention, the molar ratio of the diol component and the dicarboxylic acid component for obtaining the aliphatic polyester resin (A) having the desired degree of polymerization varies depending on the purpose and the type of raw material, but the dicarboxylic acid component 1 The lower limit of the amount of the diol component per mol is usually 0.8 mol or more, preferably 0.9 mol or more, and the upper limit is usually 1.5 mol or less, preferably 1.3 mol or less, particularly preferably 1.2 mol. It is less than a mole.

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

It should be noted that, in the middle of the manufacturing process of the above-mentioned aliphatic polyester resin (A), or in the manufactured aliphatic polyester resin (A), various additives such as heat stabilizers and oxidation are used as long as the characteristics are not impaired. An inhibitor, a crystal nucleating agent, a flame retardant, an antistatic agent, a mold release agent, an ultraviolet absorber and the like may be added. The same applies to the aromatic aliphatic copolymerized polyester resin (B), the aliphatic oxycarboxylic acid-based polyester resin (C) and the carbodiimide compound (D), which will be described later.

The aliphatic polyester resin (A) used in the present invention preferably has a glass transition temperature of 0 ° C. or lower. If the glass transition temperature exceeds 0 ° C., the flexibility decreases, which is not preferable. The glass transition temperature of the aliphatic polyester resin (A) is preferably −120 ° C. or higher and −5 ° C. or lower. The glass transition temperature can be obtained by recording the glass transition start temperature when the temperature is continuously raised at a rate of 10 ° C./min after observing the crystallization temperature using a differential scanning calorimeter.

The melt flow index (MFR) of the aliphatic polyester resin (A) used in the present invention has a lower limit of usually 0.1 g / 10 minutes or more and an upper limit of usually 100 g / 10 minutes when measured at 190 ° C. and 2.16 kg. It is 10 minutes or less, preferably 50 g / 10 minutes or less, more preferably 30 g / 10 minutes or less, and particularly preferably 10 g / 10 minutes or less.

When two or more kinds of the aliphatic polyester resin (A) are used, or when two or more kinds of the aromatic aliphatic copolymerized polyester resin (B) and the aliphatic oxycarboxylic acid-based polyester resin (C) described later are used. The MFR is calculated as an apparent MFR from the MFR of each resin and its ratio.
For example, as the aliphatic polyester resin (A), an aliphatic polyester resin (A-1) having an MFR of Ma-1 g / 10 minutes is x% by mass, and an aliphatic polyester resin having an MFR of Ma-2 g / 10 minutes is used. (A-2) When 100% by mass of y is mixed and used, the apparent MFR is log [MFR] =
(X / 100) x log [Ma-1] + (y / 100) x log [Ma-2]
It can be calculated by. The same applies to the aromatic aliphatic copolymerized polyester resin (B) and the aliphatic oxycarboxylic acid-based polyester resin (C).

In the present invention, the aliphatic polyester resin (A) is not limited to one kind, and as described above, two or more kinds of aliphatic polyester resins (A) having different types of constituents, component ratios, manufacturing methods, physical characteristics, etc. are blended. Can be used.

<Aromatic aliphatic copolymerized polyester resin (B)>
The aromatic aliphatic copolymerized polyester resin (B) contains an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit as essential components, and the content of the aromatic dicarboxylic acid unit is the aliphatic dicarboxylic acid unit. It is preferably 5 to 50 mol% with respect to the total of the aromatic dicarboxylic acid unit and the aromatic dicarboxylic acid unit. The aliphatic diol unit contained in the aromatic aliphatic copolymerized polyester resin (B) is represented by the following formula (3), the aliphatic dicarboxylic acid unit is represented by the following formula (4), and the aromatic dicarboxylic acid unit is represented by the following formula. It is preferably represented by the formula (5).
-OR ³ -O- (3)
-OC-R ⁴ -CO- (4)
-OC-R ⁵ -CO- (5)
(In the above formula (3), R ³ represents a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group, and in the formula (4), R ⁴ is a direct bond and a divalent aliphatic hydrocarbon. Represents a hydrogen group or a divalent alicyclic hydrocarbon group, and in formula ( ⁵ ), R5 represents a divalent aromatic hydrocarbon group).

The aliphatic diol component (b-3) giving the aliphatic diol unit of the formula (3) usually has 2 or more and 10 or less carbon atoms, and is, for example, ethylene glycol, 1,3-propanediol, 1,4. -Butandiol, 1,4-cyclohexanedimethanol and the like can be mentioned, among which ethylene glycol and 1,4-butanediol are preferable, and 1,4-butanediol is particularly preferable.

The aliphatic dicarboxylic acid component (b-4) giving the aliphatic dicarboxylic acid unit of the formula (4) usually has 2 or more and 10 or less carbon atoms, and is, for example, succinic acid, adipic acid, suberic acid, and sebacic acid. , Dodecanedioic acid and the like, of which succinic acid and adipic acid are preferable.

Examples of the aromatic dicarboxylic acid component (b-5) giving the aromatic dicarboxylic acid unit of the formula (5) include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like, and among them, terephthalic acid and isophthalic acid are preferable. Terephthalic acid is particularly preferred.

It should be noted that two or more types of the aliphatic diol component (b-3), the aliphatic dicarboxylic acid component (b-4), and the aromatic dicarboxylic acid component (b-5) can be used.

In the aromatic aliphatic copolymerized polyester resin (B) used in the present invention, it is necessary that an aliphatic chain is present between the aromatic rings in order to exhibit biodegradability. Therefore, the amount of the aromatic dicarboxylic acid unit in the aromatic aliphatic copolymerized polyester resin (B) has a lower limit with respect to the total of the aliphatic (and / or alicyclic dicarboxylic acid) unit and the aromatic dicarboxylic acid unit. It is preferably 5 mol% or more, more preferably 10 mol% or more, particularly preferably 15 mol% or more, and the upper limit is preferably 55 mol% or less, more preferably 48 mol% or less. If this amount is too small, the effect of improving the mechanical strength such as tear strength tends to be low when the composition is made with the aliphatic polyester resin (A). If it is too much, the biodegradability tends to be insufficient.

The aromatic aliphatic copolymerized polyester resin (B) used in the present invention may further contain an aliphatic oxycarboxylic acid unit.

Specific examples of the aliphatic oxycarboxylic acid component that gives the aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 3-hydroxy-n-valeric acid, ε-caprolactone, and 2-hydroxycapron. Examples thereof include acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, and mixtures thereof. Alternatively, these lower alkyl esters and intramolecular esters may be used. Further, when optical isomers are present in these, any of D-form, L-form, and racemic form may be used, and the form may be any of solid, liquid, and aqueous solution. Of these, lactic acid or glycolic acid is preferred. These aliphatic oxycarboxylic acid components can be used alone or as a mixture of two or more.

When the aromatic aliphatic copolymerized polyester resin (B) contains these aliphatic oxycarboxylic acid components, the content thereof is the lower limit among all the constituent components constituting the aromatic aliphatic copolymerized polyester resin (B). Is more than 0 mol%, preferably 0.01 mol% or more, and the upper limit is usually 30 mol% or less, preferably 20 mol% or less.

Further, a urethane bond, an amide bond, a carbonate bond, an ether bond and the like can be introduced into the aromatic aliphatic copolymerized polyester resin (B) as long as the biodegradability is not affected.

The aromatic aliphatic copolymerized polyester resin (B) can be produced by the same production method as the above-mentioned aliphatic polyester resin (A).

The melt flow index (MFR) of the aromatic aliphatic copolymerized polyester resin (B) used in the present invention has a lower limit of usually 0.1 g / 10 minutes or more when measured at 190 ° C. and 2.16 kg, and an upper limit of the melt flow index (MFR). Is usually 100 g / 10 minutes or less, preferably 50 g / 10 minutes or less, more preferably 30 g / 10 minutes or less, and particularly preferably 10 g / 10 minutes or less.

As for the aromatic aliphatic copolymerized polyester resin (B), one kind may be used alone, and two or more kinds of aromatic aliphatic copolymerized polyester resins having different types of constituents, component ratios, manufacturing methods, physical properties, etc. may be used. (B) can also be blended and used.

<Alphatic oxycarboxylic acid-based polyester resin (C)>
The aliphatic oxycarboxylic acid-based polyester resin (C) contains an aliphatic oxycarboxylic acid unit as an essential component, and the aliphatic oxycarboxylic acid unit is preferably represented by the following formula (6).
-OR ⁶ -CO- (6)
(In the above formula (6), R ⁶ represents a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group.)

Specific examples of the aliphatic oxycarboxylic acid component (c-6) giving the aliphatic oxycarboxylic acid unit of the formula (6) include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, and 3-hydroxy-n-kichi. Examples thereof include grass acid, ε-caprolactone, 2-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, or a mixture thereof. When optical isomers are present in these, either D-form or L-form may be used. Of these, lactic acid or glycolic acid is preferred. Two or more kinds of these aliphatic oxycarboxylic acid components (c-6) can be mixed and used. The aliphatic oxycarboxylic acid-based polyester resin (C) usually contains 50 mol% or more, preferably 70, of these aliphatic oxycarboxylic acid units in all the constituents constituting the aliphatic oxycarboxylic acid-based polyester resin (C). It contains ~ 100 mol%.

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

The method for producing the aliphatic oxycarboxylic acid-based polyester resin (C) used in the present invention is not particularly limited, and may be a direct polymerization method for oxycarboxylic acid, a ring-opening polymerization method for cyclic bodies, a microbial production method, or the like. It can be produced by a known method.

The aliphatic oxycarboxylic acid-based polyester resin (C) used in the present invention may be crystalline or amorphous, but the one having crystalline property suppresses the hydrolyzability of the obtained resin composition for plant protection materials. It is preferable. The crystallinity / amorphousness is determined by the melting peak when the sample once melted in the differential scanning calorimetry measurement is cooled and solidified at 10 ° C / min and then continuously heated at a rate of 10 ° C / min. It can be carried out depending on the presence or absence of.

The aliphatic oxycarboxylic acid-based polyester resin (C) used in the present invention preferably has a glass transition temperature of 0 ° C. or higher. The aliphatic oxycarboxylic acid-based polyester resin (C) having a glass transition temperature of less than 0 ° C. has a small effect of improving mechanical properties. The glass transition temperature of the aliphatic oxycarboxylic acid-based polyester resin (C) is preferably 50 ° C. or higher, and usually 90 ° C. or lower. The glass transition temperature of the aliphatic oxycarboxylic acid-based polyester resin (C) can be measured by the same method as described in the above section of the aliphatic polyester resin (A).

The lower limit of the melt flow index (MFR) of the aliphatic oxycarboxylic acid-based polyester resin (C) used in the present invention is usually 0.1 g / 10 minutes or more when measured at 190 ° C. and 2.16 kg, and the upper limit is set. Is usually 100 g / 10 minutes or less, preferably 50 g / 10 minutes or less, and more preferably 30 g / 10 minutes or less.

As for the aliphatic oxycarboxylic acid-based polyester resin (C), one kind may be used alone, and two or more kinds of aliphatic oxycarboxylic acid-based polyester resins having different types of constituents, component ratios, manufacturing methods, physical properties, etc. may be used. (C) can also be blended and used.

<Carbodiimide compound (D)>
The resin composition for a plant protective material of the present invention contains a carbodiimide compound (D) mainly for the purpose of suppressing hydrolysis of the components (A) to (C) due to moisture in the atmosphere or the like.

The carbodiimide compound (D) used is a compound having one or more carbodiimide groups in the molecule (including a polycarbodiimide compound), and such a carbodiimide compound may be, for example, an organic phosphorus compound or an organic metal compound as a catalyst. It can be synthesized by subjecting an isocyanate compound to a decarbonation condensation reaction in a solvent-free or inert solvent at a temperature of 70 ° C. or higher.

Among such carbodiimide compounds, examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, and di-β-naphthyl. Carbodiimide and the like can be exemplified. Among these, dicyclohexylcarbodiimide and diisopropylcarbodiimide are preferable because they are easily available industrially.

Examples of the polycarbodiimide compound include US Pat. No. 2,941956, JP-A-47-33279, J. Mol. Org. Chem. Vol. 28, p2069-2075 (1963), and Chemical Review 1981, Vol. 81, No. 4, p. Those manufactured by the method described in 619-621 and the like can be used.

Examples of the organic diisocyanate which is a raw material for producing the polycarbodiimide compound include aromatic diisocyanate, aliphatic diisocyanate, alicyclic diisocyanate and mixtures thereof, and specifically, 1,5-naphthalenediisocyanate, 4, 4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4- Mixture of tolylene diisocyanate and 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexanediisocyanate, tetramethylxyl Examples thereof include range isocyanate, 2,6-diisopropylphenylisocyanate, 1,3,5-triisopropylbenzene-2,4-diisocyanate and the like.

Examples of the carbodiimidization catalyst used for the decarbonation condensation reaction of the organic diisocyanate include an organic phosphorus compound and an organic metal compound represented by the general formula M (OR) n (where M is titanium, sodium, potassium, vanadium, tungsten, hafnium). , Zirconium, lead, manganese, nickel, calcium, barium and other metal atoms, R represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n can be a metal atom M. (Indicating valence) is preferable. Among them, phosphorene oxides are preferable for organophosphorus compounds, and titanium, hafnium, or zirconium alcosides are preferable for organometallic compounds because of their high activity.

Specific examples of phosphorene oxides include 3-methyl-1-phenyl-2-phosphoren-1-oxide, 3-methyl-1-ethyl-2-phosphoren-1-oxide, and 1,3-dimethyl-2. -Phosphoren-1-oxide, 1-phenyl-2-phosphoren-1-oxide, 1-ethyl-2-phosphoren-1-oxide, 1-methyl-2-phosphoren-1-oxide and their double bond isomers Can be exemplified. Of these, 3-methyl-1-phenyl-2-phosphoren-1-oxide, which is easily available industrially, is particularly preferable.

When synthesizing these polycarbodiimide compounds, an active hydrogen-containing compound capable of reacting with monoisocyanate or other terminal isocyanate groups can be used to control the degree of polymerization to a desired degree. Examples of the compound used for such a purpose include monoisocyanate compounds such as phenylisocyanate, tolylisocyanate, dimethylphenylisocyanate, cyclohexylisocyanate, butylisocyanate, and naphthylisocyanate, methanol, ethanol, phenol, cyclohexanol, and N-methylethanolamine. Hydroxyl group-containing compounds such as polyethylene glycol monomethyl ether and polypropylene glycol monomethyl ether, amino group-containing compounds such as diethylamine, dicyclohexylamine, β-naphthylamine and cyclohexylamine, carboxyl group-containing compounds such as succinic acid, benzoic acid and cyclohexanoic acid, and ethyl mercaptan. , Allyl mercaptan, mercapto group-containing compounds such as thiophenol, and various epoxy group-containing compounds can be exemplified.

In the present invention, it is particularly preferable to use a polycarbodiimide compound as the carbodiimide compound (D), and the degree of polymerization thereof has a lower limit of 2 or more, preferably 4 or more, and an upper limit of usually 40 or less, preferably 20 or less. .. If this degree of polymerization is too large, the dispersibility in the composition becomes insufficient, which may cause poor appearance in an inflation film, for example.

One of these carbodiimide compounds (D) may be used alone, or two or more thereof may be mixed and used.

A preferable specific compound of the carbodiimide compound (D) is an aliphatic polycarbodiimide compound, and examples of commercially available products thereof include a carbodilite series manufactured by Nisshinbo, HMV8CA and LA-1. As the aromatic polycarbodiimide compound, the Starbucksol series manufactured by Rheinchemy Co., Ltd. is preferably used.

<Content ratio of components (A) to (D)>
In the resin composition for plant protection materials of the present invention containing the components (A) to (D) as essential components, the content ratio of the component (A) is the upper limit in the total of 100 parts by mass of the components (A) to (C). Is preferably 85 parts by mass or less, more preferably 80 parts by mass or less, particularly preferably 75 parts by mass or less, and the lower limit is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more. Is. When the content ratio of the component (A) is not more than the above upper limit, desired physical properties can be obtained without biodegradation being too fast and without becoming too soft, while the content ratio of the component (A) is described above. When it is at least the lower limit, biodegradation does not become too slow, sufficient flexibility can be obtained, and it is suitable as a plant protection material.

The content ratio of the component (B) is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and particularly preferably 40 parts by mass or less in the total 100 parts by mass of the components (A) to (C). The lower limit is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more. When the content ratio of the component (B) is not more than the above upper limit, the desired physical properties can be obtained without the biodegradation becoming too slow or too soft, while the content ratio of the component (B) is more than the above lower limit. If it is, it is possible to obtain sufficient breaking strength, flexibility, and elongation, and it is suitable as a plant protection material without deterioration during use.

The content ratio of the component (C) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and particularly preferably 20 parts by mass or less, based on 100 parts by mass of the total of the components (A) to (C). The lower limit is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and particularly preferably 5 parts by mass or more. When the content ratio of the component (C) is not more than the above upper limit, biodegradation does not become too slow or too hard, it is easy to wrap it around a plant, and desired physical properties can be obtained, while the component (C) When the content ratio of is not more than the above lower limit, biodegradation does not occur too quickly and the vertical and horizontal elongation balance does not deteriorate, which is suitable as a plant protection material.

Further, in the resin composition for a plant protective material of the present invention, the content of the component (D) is preferably 2 parts by mass or less with respect to a total of 100 parts by mass of the components (A) to (C). It is preferably 1 part by mass or less, particularly preferably 0.8 part by mass or less, and the lower limit is preferably 0.1 part by mass or more, more preferably 0.2 part by mass or more, and particularly preferably 0.3 part by mass or more. be. When the content of the component (D) is not more than the above upper limit, cross-linking does not easily proceed, physical properties deteriorate, molding processability is impaired, and biodegradation does not become extremely slow. On the other hand, when the content of the component (D) is at least the above lower limit, the effect of the present invention such as the effect of delaying biodegradation due to the addition of the component (D) can be sufficiently obtained, which is preferable.

<Other ingredients>
As described above, the resin composition for a plant protection material of the present invention is contained in each of the components (A) to (D), or when these components are mixed to form a resin composition, the physical properties and processing are performed. Heat stabilizers, antioxidants, lubricants, blocking inhibitors, crystal nucleating agents, colorants, pigments, flame retardants, antistatic agents, mold release agents, UV absorbers, light stabilizers, etc. for the purpose of adjusting properties, etc. Various additives such as a modifier, a cross-linking agent, a plasticizer, and a filler may be blended. In particular, it is preferable to add an ultraviolet absorber, a light stabilizer, and an antioxidant in order to maintain physical properties in an outdoor use environment. In addition, biodegradable resins other than the components (A) to (C), such as polyamide, polyvinyl alcohol, cellulose ester, etc., starch, cellulose, paper, wood powder, and chitin, are used as long as the effects of the present invention are not impaired. -A fine powder of animal / plant substances such as cellulosic, coconut shell powder, walnut shell powder, or a mixture thereof can also be blended.

<Manufacturing method of resin composition for plant protection material>
The method for producing the resin composition for a plant protective material of the present invention is not particularly limited, but is a blended aliphatic polyester resin (A), an aromatic aliphatic copolymerized polyester resin (B), and an aliphatic oxycarboxylic acid-based polyester resin. Examples thereof include a method of melting and mixing the raw material chips of (C) with the same extruder, a method of melting each of them with different extruders, and then mixing them. It is also possible to directly supply each raw material chip to a molding machine to prepare a resin composition and at the same time obtain a molded product thereof.

The carbodiimide compound (D) may be added at the time of preparation of such a composition, or may be added to the aliphatic polyester resin (A), the aromatic aliphatic copolymerized polyester resin (B) and / or the aliphatic oxycarboxylic acid system. It may be kneaded into any one or two components of the polyester resin (C) and dry-blended with the remaining components at the time of molding. Alternatively, a master batch containing a high concentration of the carbodiimide compound (D) with the aliphatic polyester resin (A), the aromatic aliphatic copolymerized polyester resin (B) and / or the aliphatic oxycarboxylic acid-based polyester resin (C) is prepared. The aliphatic polyester resin (A), the aromatic aliphatic copolymerized polyester resin (B) and / or the aliphatic oxycarboxylic acid-based polyester resin (C) so that the carbodiimide compound (D) has a predetermined concentration at the time of molding. May be dry blended and diluted.

<MFR of resin composition for plant protection material>
The resin composition for a plant protective material of the present invention has a melt flow index (MFR) of 1 g, which is measured by the method described in the section of Examples below, in order to sufficiently obtain molding processability as a plant protective material. It is preferably / 10 minutes or more, particularly 1.2 g / 10 minutes or more, and preferably 1.5 g / 10 minutes or less, particularly 5 g / 10 minutes or less. When the MFR is at least the above lower limit, the molding processability is excellent, while when it is at least the above upper limit, the mechanical strength of the obtained plant protective material is excellent, which is preferable.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The following examples are shown for the purpose of explaining the present invention in detail, and the present invention is not limited to the following examples unless contrary to the gist thereof.

[Measurement and evaluation method]
In the following, various physical properties and characteristics were measured and evaluated by the following methods.

<MFR measurement>
The MFR value was measured at 190 ° C. and a load of 2.16 kg using a melt indexer based on JIS K7210 (1990).

<Tensile test>
Punch a dumbbell-shaped sample in MD and TD of inflation film, and measure elastic modulus (MPa), tensile yield strength (MPa), tensile breaking strength (MPa), and tensile elongation retention rate (%) according to JIS K7113. bottom.

<Thickness measurement>
The film thickness was measured at 5 points using a micrometer for the test pieces punched out for various tests using a micrometer, and the average value was taken as the thickness. The table shows the thickness of the test piece in the tensile test MD direction. The thickness described in the biodegradability test is the one immediately before the tensile test.

<Evaluation of moldability>
With an inflation molding machine having a 40 mm extruder and a round die with a diameter of 60 mm, the set thickness is 350 μm, the discharge rate is 8 kg / h, the air blow is constant, the moldability (bubble, frosted state), and the film mouth opening property. The surface appearance was examined and evaluated according to the following criteria.
<Evaluation criteria for moldability>
5: Low frost line, stable bubbles and good moldability 4: High frost line, but no problem with moldability 3: High frost line, slightly problem with moldability 2: Frost line Very high, very unstable bubbles and problematic formability 1: Motor load is high and cannot be extruded.

<Evaluation of shape stability>
The sheet was wrapped around the roadside trees in the Yokkaichi Plant of Mitsubishi Chemical Co., Ltd. in Yokkaichi, Mie Prefecture for 5 months, and the presence or absence of shape changes was confirmed. When it fell off with cracks, it was defined as "deformed", and when it did not fall off, or when it fell off but did not crack, it was defined as "no deformation".

<Hydrolytic test>
The film was punched into a dumbbell shape and stored in a constant temperature and humidity chamber at 40 ° C. and 90% RH for the period shown in Table 1, and then allowed to stand at 23 ° C. and 50% RH for 1 day or more, and then the above-mentioned tensile strength. Tensile yield strength (MPa), tensile breaking strength (MPa), and tensile elongation retention rate (%) were measured according to the test method.

<Biodegradability test>
Put soil with 20% water content (farm soil in Mie prefecture) in a polyethylene container, arrange samples with a dumbbell-shaped film on it, cover it with soil to a thickness of about 1 cm, and set it at 40 ° C. Stored in an incubator. After the time shown in Table 1, it is taken out, and the adhering soil is carefully brushed off, and then allowed to stand at 23 ° C. and 50% RH for 1 day or more. μm) (13 weeks only), tensile yield strength (MPa), tensile breaking strength (MPa), and tensile elongation retention rate (%) were measured.

<Evaluation of thermal properties>
The glass transition temperature and melting point were measured as follows.
Using a differential scanning calorimeter manufactured by SEIKO, product name: DSC6220, a 10 mg sample was heated and melted under a nitrogen flow rate of 50 mL / min, cooled to −100 ° C., and held for 5 minutes. Then, the temperature was raised to 200 ° C. at a rate of 10 ° C./min, held for 5 minutes, and then cooled at a rate of 10 ° C./min. At that time, the glass transition start temperature and the melting peak temperature at the time of temperature rise were defined as the glass transition temperature and the melting point, respectively.

[Materials used and their physical characteristics]
Details of the materials used in the following examples and comparative examples are as follows.
Aliphatic polyester resin (A): PBS (polybutylene succinate) (BioPBS FZ91 series manufactured by PTTMCC)
Melting point: 115 ° C
Glass transition temperature: -22 ° C
MFR (190 ° C., 2.16 kg): 5 g / 10 minutes Aromatic aliphatic copolymerized polyester resin (B): PBAT (poly (poly (butylene adipate-co-butylene terephthalate))) (ECOFLEX FBlend C1200 manufactured by BASF)
Ratio of terephthalic acid component in dicarboxylic acid component: 52 mol%
MFR (190 ° C, 2.16 kg): 2.9 g / 10 minutes Glass transition temperature: -40 ° C
Melting point: 110-125 ° C
Aliphatic oxycarboxylic acid-based polyester resin (C): PLA (crystalline polylactic acid) (INGEO 4032D manufactured by NatureWorks)
Glass transition temperature: 58 ° C
MFR (190 ° C., 2.16 kg): 3.2 g / 10 minutes Carbodiimide compound (D): CDI (aliphatic polycarbodiimide) (Carbodilite LA-1 manufactured by Nisshinbo)
Inorganic filler (E): talc (MG115 manufactured by Fuji Talc Industry Co., Ltd.)

[Examples 1 to 4, Comparative Examples 1 to 3]
<Example 1>
55.0 parts by mass of PBS as the aliphatic polyester resin (A), 30.0 parts by mass of PBAT as the aromatic aliphatic copolymerized polyester resin (B), and PLA as the aliphatic oxycarboxylic acid-based polyester resin (C). Using 15.0 parts by mass and 0.3 parts by mass of carbodilite LA-1 which is a carbodiimide compound (D), these are dry-blended and cylinderd with a twin-screw kneader (manufactured by Japan Steel Works, Ltd .; TEX30). The temperature was 200 ° C., the screw rotation speed was 200 rpm, the screw rotation direction was the same, and the resin composition was extruded into strands at a discharge rate of 20 kg / h, cooled with water, and then cut into pellets with a pelletizer to obtain a resin composition. The MFR of the obtained composition was measured and the results are shown in Table 1.

Next, a single-layer inflation film forming machine (manufactured by Misuzu Erie Co., Ltd., product name: MK-40, extruder cylinder diameter = 40 mm, round die diameter = 60 mm, die lip gap width = 1 mm, equipped with dual lip type air ring). An inflation film having a cylinder temperature, a die temperature of 190 ° C., a blow-up ratio of 2, a discharge rate of 10 kg / h, and a constant air blow was prepared, and the set film thickness was 350 μm. As moldability, extrudability, bubble stability, frost line height, mouth opening property of the obtained film, and appearance were comprehensively evaluated. As the quality of the obtained film, tensile elastic modulus (MPa), tensile yield strength (MPa), tensile breaking strength (MPa), and tensile elongation retention rate (%) were measured and shown in the column of origin in Table 1. .. Further, shape stability, hydrolyzability test, and biodegradability test were carried out, and the results are shown in Table 1.

<Example 2>
In Example 1, the same procedure as in Example 1 was carried out except that the blending amount of the carbodiimide compound (D) was changed to 0.5 parts by mass, and the evaluation was carried out in the same manner. The results are shown in Table 1.

<Example 3>
In Example 1, the same procedure as in Example 1 was carried out except that the blending amount of the carbodiimide compound (D) was changed to 0.8 parts by mass, and the evaluation was carried out in the same manner. The results are shown in Table 1.

<Example 4>
In Example 1, the same procedure as in Example 1 was carried out except that the blending amount of the carbodiimide compound (D) was changed to 1.0 part by mass, and the evaluation was carried out in the same manner. The results are shown in Table 1.

<Comparative Example 1>
In Example 1, the same procedure was carried out except that the carbodiimide compound (D) was not blended, and the evaluation was carried out in the same manner. The results are shown in Table 2.

<Comparative Example 2>
60.0 parts by mass of PBS is used as the aliphatic polyester resin (A), 30.0 parts by mass of PBAT is used as the aromatic aliphatic copolymerized polyester resin (B), and 10.0 parts by mass of talc is used as the inorganic filler (E). , These are dry-blended, and the cylinder temperature is 200 ° C., the screw rotation speed is 200 rpm, the screw rotation direction is the same, and the strand is discharged at a discharge rate of 20 kg / h in a twin-screw kneader (manufactured by Japan Steel Works, Ltd .; TEX30). It was extruded into a shape, cooled with water, and then cut into pellets with a pelletizer to obtain a resin composition. Other than that, molding and evaluation were performed in the same manner as in Example 1. The results are shown in Table 2.

<Comparative Example 3>
In Example 1, a resin composition was produced in the same manner except that the blending amount of the carbodiimide compound (D) was changed to 3 parts by mass, but the obtained resin composition had an MFR of 0.8 g / 10 minutes. The film was not able to be formed because it was very small and the load on the extruder motor was large.

The following can be seen from Tables 1 and 2.
In Examples 1 to 4, the moldability was improved by containing the carbodiimide compound (D) as compared with Comparative Examples 1 and 2. Further, from the results of the hydrolyzability test, it can be seen that the composition has excellent tensile properties until 13 weeks and is excellent in storage in a warehouse or the like. Furthermore, from the biodegradability test results and the evaluation results of shape stability, the initial physical properties are maintained up to 5 weeks, and when installed on trees, etc., they can withstand long-term installation, and the trees, etc. are damaged by birds and animals for the desired period. It turns out that it is possible to protect from.
Comparative Example 3 was a case where 3 parts by mass of the carbodiimide compound (D) was added, and the MFR of the resin composition was significantly lowered, and molding was not possible.

Claims (6)

Aliphatic polyester resin (A) containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, an aromatic aliphatic copolymerized polyester resin (B) containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit. , A plant protective material comprising a resin composition containing a polyester resin (C) containing an aliphatic oxycarboxylic acid unit and a carbodiimide compound (D) .
The melt flow index (MFR) of the resin composition is 1 g / 10 minutes or more and 5 g / 10 minutes or less.
The carbodiimide compound (D) is contained in an amount of 0.1 to 2 parts by mass based on 100 parts by mass of the total of the aliphatic polyester resin (A), the aromatic aliphatic copolymerized polyester resin (B) and the polyester resin (C). Plant protection material. The plant protection material according to claim 1, wherein the carbodiimide compound (D) is a polycarbodiimide compound. The plant protection material according to claim 2, wherein the polycarbodiimide compound is an aliphatic polycarbodiimide compound. The plant protection material according to any one of claims 1 to 3 , which is in the form of a net, a cylinder, or a sheet. The plant protection material according to any one of claims 1 to 4 , which is used by wrapping around a plant. Aliphatic polyester resin (A) containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, an aromatic aliphatic copolymerized polyester resin (B) containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit. , A resin composition for a plant protective material containing a polyester resin (C) containing an aliphatic oxycarboxylic acid unit, and a carbodiimide compound (D) .
The melt flow index (MFR) of the resin composition for plant protection material is 1 g / 10 minutes or more and 5 g / 10 minutes or less.
The carbodiimide compound (D) is contained in an amount of 0.1 to 2 parts by mass based on 100 parts by mass of the total of the aliphatic polyester resin (A), the aromatic aliphatic copolymerized polyester resin (B) and the polyester resin (C). Resin composition for plant protection materials.