JP7150109B2 - Plant cultivation medium, plant cultivation apparatus, and plant cultivation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a medium for plant cultivation, and a plant cultivation apparatus and a plant cultivation method using the medium.

Hydroponic culture does not use soil to cultivate crops, so there is no failure of continuous cropping, and it is not influenced by soil diseases and growth conditions, and it is easy to control the cultivation environment and nutrient water management. In addition, it is attracting attention as a cultivation method that can be automated and labor-saving, and has high cleanliness of the harvested product and fertilizer efficiency.

Since a solid medium for hydroponics is immersed in water, it is required to have a certain degree of water resistance, as well as water permeability, water retention, air permeability, strength, and the like. Conventionally, as a solid medium for hydroponics, rock wool, etc., which are made by converging fibrous natural stones (mainly basalt), are known.

In hydroponic cultivation, the roots tend to stick to the inside of the solid medium, so it may be necessary to replace the solid medium with a new solid medium, but when rock wool is used as the solid medium, recycling is difficult. There is Moreover, since rock wool is an inorganic substance, there is no effective disposal method for rock wool after use. Currently, there are methods for disposing of used rock wool, such as disposing of it as industrial waste and plowing it into rice fields little by little. . In addition, since rock wool retains too much water, it is difficult to grow root crops, for example, because they cannot grow. Therefore, it maintains physical properties such as water resistance, water permeability, water retention, air permeability, strength, etc. necessary as a medium for plant cultivation, and is physically and chemically stable, allowing crops to grow sufficiently. There is a demand for a medium with a low load on the

In Patent Document 1, the applicant proposes a plant cultivation medium containing ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as "EVOH") chips. According to the plant cultivation medium described in Patent Document 1, it is possible to sufficiently grow crops, it is excellent in recyclability, it can be used repeatedly, and it can be easily disposed of by incineration after use. Therefore, it is possible to provide a plant cultivation medium with a low environmental load.

On the other hand, in recent years, the demand for bioplastics using biomass-derived raw materials such as carbon-neutral biomass has been increasing with the aim of realizing a recycling-oriented society. However, it is known that biomass-derived synthetic resins are sometimes inferior in performance to fossil fuel-derived synthetic resins. For example, in Patent Document 2, it is said that conventional film materials such as biomass-derived polyolefins have insufficient qualities such as adhesion, workability, and durability. An invention of a resin film provided with a biomass-derived resin layer of a specific composition containing In addition, in Patent Document 3, it is said that a film obtained by replacing a petroleum-derived resin with a biomass-derived resin may have reduced impact resistance, etc. In order to improve such points, biomass-derived polyethylene and an invention of a laminated film having an intermediate layer containing polyethylene derived from fossil fuel and a propylene-based block copolymer resin.

WO2012/108374 WO2014/065380 WO2018/163835

As for the medium for cultivating plants, commercialization of the medium synthesized using biomass-derived raw materials is expected. However, as described above, biomass-derived synthetic resins may have inferior performance compared to fossil fuel-derived synthetic resins. When replaced, there is concern that the most important plant viability will decline. Therefore, there is a demand for the development of a biomass-derived resin that has excellent plant growth properties comparable to those derived from fossil fuels.

In addition, the resin-made plant cultivation medium is often molded into a chip shape by melt molding. Therefore, in order to efficiently produce a resin-made plant cultivation medium, it is necessary to stably and efficiently obtain a chip-shaped plant cultivation medium even if melt molding is continued for a long period of time. Long-run properties (long-term operation characteristics) of resin materials are important. When a resin material with insufficient long-run properties is used, deposits on the extruder die tend to occur during long-term melt molding. Further, when a resin material with insufficient long-run properties is used, when the molten resin material is extruded into strands, the strands (strand-shaped resin material) are likely to break, resulting in poor productivity. In addition, hereinafter, the breakage of the strand is also referred to as "strand breakage".

The present invention has been made based on the above circumstances, and its object is to develop a resin composition that uses biomass-derived raw materials and has sufficient long-run properties comparable to those derived from fossil fuels. It is an object of the present invention to provide a plant cultivating medium that is formed and has high plant growth, and a plant cultivating apparatus and a plant cultivating method using this plant cultivating medium.

The present inventors have found that in the saponified ethylene-vinyl ester copolymer, a plant cultivation medium formed from a material synthesized using a biomass-derived raw material as a monomer is obtained by using a fossil fuel-derived raw material as a monomer. It has been found that the plant growth medium is as high as a plant cultivation medium formed from a conventional synthetic material having the same structure. On the other hand, in terms of long-run performance, saponified ethylene-vinyl ester copolymers synthesized using biomass-derived raw materials as monomers are inferior to those synthesized using fossil fuel-derived raw materials as monomers. It was also found that there was a difference in gender. For this reason, the present inventors have found that if an ethylene-vinyl ester copolymer saponified product in which a biomass-derived raw material and a fossil fuel-derived raw material are used in combination, while reducing the environmental load, fossil fuel-derived The present inventors have found that a medium for cultivating plants having the same high plant growth properties as those obtained by using only the raw material of (1) can be produced, and also have sufficient long-run properties, leading to the completion of the present invention.

That is, the present invention
[1] A plant cultivation medium containing a molded body formed from a resin composition, wherein the resin composition contains one or more saponified ethylene-vinyl ester copolymers, and the one or A medium for cultivating plants, in which a part of ethylene and vinyl ester, which are raw materials of two or more ethylene-vinyl ester copolymer saponified products, is derived from biomass and the remainder is derived from fossil fuel;
[2] The one or more saponified ethylene-vinyl ester copolymers are the saponified ethylene-vinyl ester copolymer (A) in which at least part of the raw materials ethylene and vinyl ester is derived from biomass. , the ethylene-vinyl ester copolymer saponified product (B) derived from fossil fuel, and the plant cultivation medium of [1];
[3] The saponified ethylene-vinyl ester copolymer (A) and the saponified ethylene-vinyl ester copolymer (B) have a mass ratio (A/B) of 1/99 to 99/1. [2] plant cultivation medium;
[4] The saponified product of one or more ethylene-vinyl ester copolymers is an ethylene-vinyl ester copolymer in which part of the raw materials ethylene and vinyl ester is derived from biomass and the remainder is derived from fossil fuel. The plant cultivation medium of [1], comprising the combined saponified product (A');
[5] The plant cultivation medium of any one of [1] to [4], wherein the one or more saponified ethylene-vinyl ester copolymers have a biobased degree of 1% or more and 99% or less;
[6] The plant cultivation medium according to any one of [1] to [5], wherein the biobased degree of the resin composition is 1% or more and 99% or less;
[7] The medium for plant cultivation according to any one of [1] to [6], wherein the resin composition contains sulfur compounds exceeding 0 ppm and not more than 100 ppm in terms of sulfur atoms;
[8] The plant cultivation medium of [7], wherein the sulfur compound is dimethylsulfide or dimethylsulfoxide;
[9] The medium for cultivating plants according to any one of [1] to [8], wherein at least part of the ethylene in the raw material is derived from biomass;
[10] The plant cultivation medium according to any one of [1] to [9], wherein at least part of the vinyl ester among the raw materials is derived from biomass;
[11] The medium for plant cultivation according to any one of [1] to [10], wherein the molded article is a resin composition chip;
[12] The plant cultivation medium of [11], wherein the shape of the resin composition chips is columnar, flat, or flaky;
[13] A plant cultivation device comprising the plant cultivation medium according to any one of [1] to [12];
[14] A plant cultivation method comprising a step of cultivating using the plant cultivation medium of any one of [1] to [12];
This is achieved by providing

According to the present invention, a plant cultivation medium having high plant growth, which is formed from a resin composition having sufficient long-run properties comparable to those derived from fossil fuels while using biomass-derived raw materials, Also, a plant cultivation apparatus and a plant cultivation method using this plant cultivation medium can be provided.

It is a mimetic diagram showing a plant cultivation device concerning one embodiment of the present invention.

<Plant cultivation medium>
A plant cultivation medium of the present invention includes a molded body formed from a predetermined resin composition. That is, the plant cultivation medium of the present invention includes molded bodies such as pellets and chips obtained by molding the resin composition. First, the resin composition will be described in detail below.
[Resin composition]
The resin composition contains one or more ethylene-vinyl ester copolymer saponified products (ethylene-vinyl alcohol copolymer; hereinafter also referred to as "EVOH"), and the one or more EVOH. Part of the raw material (raw material monomer) of ethylene and vinyl ester is derived from biomass, and the remainder of the raw material (raw material monomer) of ethylene and vinyl ester is derived from fossil fuel. The resin composition has a low environmental load because biomass-derived raw materials are partially used. In addition, the resin composition uses EVOH selected as a resin having excellent plant growth properties, and the plant cultivation medium containing the molded body using EVOH uses a raw material whose EVOH is derived from biomass. Even in the case of being synthesized, high plant growth properties equivalent to those of EVOH having the same structure synthesized only from raw materials derived from fossil fuels can be exhibited. EVOH having the same structure means EVOH having the same degree of polymerization, the content ratio of each structural unit, the presence or absence of modification, the degree of saponification, and the like. Furthermore, in the resin composition, EVOH is used in combination with raw materials derived from fossil fuels, so long-run properties are sufficient. Although the reason why the present invention exhibits such an effect is not clear, when EVOH is synthesized using a biomass-derived raw material, although it does not affect plant growth, it does affect long-run performance. It is assumed that unavoidable impurities are generated or mixed.

Here, the long-run property in the present specification can be evaluated by the method described in Examples, and can be comprehensively evaluated by the degree of deposits on the die and the frequency of fiber breakage when the resin composition is continuously molded. In addition, plant growth means having the ability to grow plants, and can be evaluated, for example, by the number of enlarged roots in growing radishes, as in the medium evaluation described in the examples of the present invention.

It can be confirmed by measuring the biobased content that the ethylene and vinyl ester used as raw materials contain both biomass-derived and fossil fuel-derived sources. The biobased degree is an index representing the ratio of biomass-derived raw materials, and in the present specification, it is the biobased carbon content obtained by measuring the concentration of radioactive carbon ( ¹⁴ C) with an accelerator mass spectrometer (AMS). . The biobased content can be specifically measured according to the method described in ASTM D6866-18. That is, in general, when the biobased content of EVOH is more than 0% and less than 100%, it can be said that the ethylene and vinyl ester used as raw materials contain both biomass-derived and fossil fuel-derived ethylene.

As for the resin composition used in the present invention, it is also possible to trace the company's products using the concentration of radioactive carbon ( ¹⁴ C). Living organisms take in radioactive carbon ( ¹⁴ C) from the atmosphere during their activity and contain a certain amount of it, but when they stop their activity, they stop taking in new ¹⁴ C and the ratio of ¹⁴ C to total carbon decreases. In addition, it is known that a phenomenon called isotope selection occurs when plants fix carbon, and the ratio of ¹⁴ C to total carbon differs depending on the plant species. It is known that the ratio of ¹⁴ C to total carbon varies depending on the place of production and age, and raw materials with different ratios of ¹⁴ C to total carbon can be obtained depending on the biomass used as the raw material. Since very little ¹⁴ C remains in fossil fuel-derived feedstocks, it is possible to obtain EVOH with a specific ¹⁴ C to total carbon ratio, for example, by varying the ratio of biomass-derived to fossil fuel-derived feedstocks. By examining the ratio of ¹⁴ C to the total carbon, it becomes possible to trace the EVOH (resin composition) produced in-house.

EVOH is used in a wide variety of applications and it is the supplier's responsibility to provide high quality products to the market. Also, there is a need for a method of distinguishing one's own products from other companies' products for branding purposes. For example, EVOH, which is used in the gas barrier layer of commercially available packaging containers, is formed into packaging containers by thermoforming. can form Therefore, even if the packaging container is recovered, the EVOH used is extracted with a solvent, and an attempt is made to measure the molecular weight, it is often difficult to measure the molecular weight accurately. Therefore, it is not possible to determine whether or not the EVOH is the company's own EVOH only by analyzing the molded product. The same thing is also a concern for molded bodies other than thermoformed containers, such as molded bodies used for plant cultivation media.

EVOH is used in films, sheets, containers, etc. as packaging materials for foods, pharmaceuticals, industrial chemicals, agricultural chemicals, etc. through many distribution channels. It is also used for applications such as fuel tanks for vehicles such as automobiles, tire tube materials, agricultural films, geomembrane, and cushioning materials for shoes, taking advantage of its barrier properties, heat retention, and stain resistance. When these EVOH-used materials are further discarded, it is difficult to determine from which factory and from which production line the resin and the used packaging container were produced. In addition, it is difficult to investigate the quality of in-house products at the time of use or after use, and to track the environmental impact after disposal and the ability to decompose into the ground.

As one of the methods for tracking the company's own products, for example, a method of adding a tracer substance to EVOH is conceivable. However, the addition of tracers may increase costs and degrade EVOH performance. In such a background, it can be said that being able to track one's own products using the concentration of radioactive carbon ( ¹⁴ C) is a very useful effect.

(EVOH)
The forms of one or more types of EVOH contained in the resin composition include the following forms (I) and (II).
(I) Form containing EVOH (A) in which at least part of the ethylene and vinyl ester as raw materials is derived from biomass and EVOH (B) which is derived from fossil fuel (II) One of ethylene and vinyl ester as raw materials Form containing EVOH (A') partly derived from biomass and the remainder derived from fossil fuel

One or more of the EVOH may be one in which part of the ethylene units, vinyl alcohol units and vinyl ester units are derived from biomass and the remainder is derived from fossil fuels. That is, EVOH (A) may be EVOH in which at least a portion of ethylene units, vinyl alcohol units and vinyl ester units are derived from biomass. EVOH (B) may be an EVOH in which all of the ethylene units, vinyl alcohol units and vinyl ester units are derived from fossil fuels. EVOH (A′) may be an EVOH in which part of the ethylene units, vinyl alcohol units and vinyl ester units are derived from biomass, and the remainder is derived from fossil fuels.

(EVOH (A))
EVOH (A) is EVOH in which at least part of ethylene and vinyl ester as raw material monomers is derived from biomass. By including a biomass-derived raw material in EVOH (A), the bio-based degree of the resin composition can be increased and the environmental load can be reduced.

EVOH (A) is obtained by saponification of a copolymer of ethylene and vinyl ester, at least partly derived from biomass. The production and saponification of the ethylene-vinyl ester copolymer, which is the precursor of EVOH (A), should be carried out by a known method similar to the production and saponification of conventional fossil fuel-derived ethylene-vinyl ester copolymers. can be done. Examples of vinyl esters that can be used include carboxylic acid vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate. vinyl acetate is preferred.

Biomass-derived ethylene can be produced by a known method such as, for example, purifying bioethanol from a biomass raw material and subjecting it to a dehydration reaction. As biomass raw materials, waste materials, unused materials, resource crops, etc. can be used. , natural rubber, cotton, sugarcane, bean curd refuse, oils and fats (rapeseed oil, cottonseed oil, soybean oil, coconut oil, castor oil, etc.), carbohydrate crops (corn, potatoes, wheat, rice, chaff, rice bran, old rice, cassava, sago palm) etc.), bagasse, buckwheat, soybeans, essential oils (pine oil, orange oil, eucalyptus oil, etc.), pulp black liquor, vegetable oil residue and the like can be used.

The method for producing bioethanol is not particularly limited. For example, biomass raw materials are pretreated as necessary (pressurized hot water treatment, acid treatment, alkali treatment, saccharification treatment using saccharifying enzyme), and then yeast fermentation. After producing bioethanol, the bioethanol can be purified through a distillation process and a dehydration process. When saccharification treatment is performed during bioethanol production, sequential saccharification and fermentation in which saccharification and fermentation are performed in stages may be used, or parallel saccharification and fermentation in which saccharification and fermentation are performed simultaneously may be used. From a viewpoint, it is preferable to produce bioethanol by parallel saccharification and fermentation.

Commercially available biomass-derived ethylene may also be used, eg Braskem S.M. A. can be used.

Biomass-derived vinyl esters include vinyl esters produced using biomass-derived ethylene. Methods for producing vinyl esters derived from biomass include, for example, a method of reacting ethylene, acetic acid, and oxygen molecules using a palladium catalyst, which is a general industrial method. Also, the biomass-derived vinyl ester may be a vinyl ester produced using a biomass-derived carboxylic acid. If the degree of saponification of EVOH (A) is not 100 mol %, biomass-derived acyl groups will remain.

The lower limit of the ethylene unit content of EVOH (A) is preferably 20 mol%, more preferably 23 mol%, and even more preferably 25 mol%. When the ethylene unit content of EVOH (A) is 20 mol % or more, it tends to exhibit moderate water retention and tends to improve long-run properties. The upper limit of the ethylene unit content of EVOH (A) is preferably 60 mol%, more preferably 55 mol%, even more preferably 50 mol%. When the ethylene unit content of EVOH (A) is 60 mol % or less, water retention tends to increase, and plant growth tends to become better. The ethylene unit content of EVOH can be determined by a nuclear magnetic resonance (NMR) method.

The lower limit of the degree of saponification of EVOH (A) is preferably 90 mol%, more preferably 95 mol%, even more preferably 99 mol%. When the degree of saponification of EVOH (A) is 90 mol % or more, water retention tends to increase and plant growth tends to be better. Further, when the degree of saponification of EVOH (A) is 90 mol % or more, there is a tendency for the long-run property to become better. Moreover, the upper limit of the saponification degree of EVOH (A) may be 100 mol %, or may be 99.97 mol % or 99.94 mol %. The degree of saponification of EVOH can be calculated by performing ¹ H-NMR measurement and measuring the peak area of hydrogen atoms contained in the vinyl ester structure and the peak area of hydrogen atoms contained in the vinyl alcohol structure.

At least part of the ethylene and vinyl ester used as raw materials for EVOH (A) is derived from biomass, preferably at least part of the vinyl ester is derived from biomass, and all of the vinyl ester is derived from biomass. good too. At least part of the ethylene, which is the raw material of EVOH (A), is preferably derived from biomass, and all of the ethylene may be derived from biomass. In some cases, it is preferable that at least part of the vinyl ester and at least part of the ethylene, which are raw materials of EVOH (A), are derived from biomass, and all of the vinyl ester and ethylene may be derived from biomass.

The lower limit of the ratio of biomass-derived vinyl alcohol units in all vinyl alcohol units (saponified vinyl ester units) constituting EVOH (A) is preferably 1 mol%, more preferably 5 mol%, and further 10 mol%. Preferably, 25 mol% or 45 mol% is even more preferable, and it may be 70 mol%, 90 mol%, or 99 mol%, even if all vinyl alcohol units constituting EVOH (A) are derived from biomass. good. The upper limit of the ratio of vinyl alcohol units derived from fossil fuels in all vinyl alcohol units constituting EVOH (A) is preferably 99 mol%, more preferably 95 mol%, still more preferably 90 mol%, 75 mol% or 55 mol%. mol % is even more preferable, and may be 30 mol %, 10 mol %, or 1 mol %, and all vinyl alcohol units constituting EVOH (A) do not contain vinyl alcohol units derived from fossil fuels. good too. When the proportion of biomass-derived vinyl alcohol units in the total vinyl alcohol units constituting EVOH (A) increases, the degree of bio-basedness in the resin composition increases, tending to reduce the environmental load. On the other hand, from the viewpoint of providing a resin composition having an excellent balance of biobased content and long-run properties during melt molding, the proportion of biomass-derived vinyl alcohol units is preferably 5 mol% or more and 95 mol% or less, and 15 mol% or more. 85 mol % or less is more preferable, 25 mol % or more and 75 mol % or less is still more preferable, and 35 mol % or more and 65 mol % or less is particularly preferable.

The lower limit of the proportion of biomass-derived ethylene units in all ethylene units constituting EVOH (A) is preferably 1 mol%, more preferably 5 mol%, still more preferably 10 mol%, and 25 mol% or 45 mol%. Even more preferably, it may be 70 mol %, 90 mol % or 99 mol %, and all ethylene units constituting EVOH (A) may be derived from biomass. The upper limit of the ratio of fossil fuel-derived ethylene units in all ethylene units constituting EVOH (A) is preferably 99 mol%, more preferably 95 mol%, still more preferably 90 mol%, 75 mol% or 55 mol% is more preferable, and may be 30 mol %, 10 mol %, or 1 mol %, and all ethylene units constituting EVOH (A) may not contain ethylene units derived from fossil fuels. When the proportion of biomass-derived ethylene units in the total ethylene units constituting EVOH (A) increases, the degree of bio-basedness in the resin composition increases, tending to reduce the environmental load. On the other hand, from the viewpoint of providing a resin composition having an excellent balance of biobased content and long-run properties during melt molding, the ratio of biomass-derived ethylene units is preferably 5 mol% or more and 95 mol% or less, and 15 mol% or more and 85%. mol % or less is more preferable, 25 mol % or more and 75 mol % or less is even more preferable, and 35 mol % or more and 65 mol % or less is particularly preferable.

The lower limit of the biobased content of EVOH (A) is preferably 1%, more preferably 5%, even more preferably 20%, and particularly preferably 40%, from the viewpoint of reducing the environmental load of the resin composition of the present invention. Furthermore, the lower limit of the biobased content of EVOH (A) may be 60%, 80% or 95%. The upper limit of the biobased content of EVOH (A) may be 100%, but is preferably 99%, more preferably 95%, and 85%, 75% or 65% from the viewpoint of improving long-run properties. is more preferred in some cases.

EVOH (A) may have units derived from monomers other than ethylene, vinyl esters and saponified products thereof, as long as the object of the present invention is not impaired. When EVOH (A) has units derived from the other monomer, the upper limit of the content of units derived from the other monomer to all structural units of EVOH (A) is preferably 30 mol%, and 20 mol. % is more preferred, 10 mol % is more preferred, 5 mol % is even more preferred, and 1 mol % is even more preferred. Further, when EVOH (A) has units derived from the other monomers, the lower limit of the content may be 0.05 mol % or 0.10 mol %. The other monomers mentioned above are, for example, alkenes such as propylene, butylene, pentene, hexene; -1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2-methyl -1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy -Alkenes having an ester group such as 1-hexene, 5,6-diacyloxy-1-hexene, 1,3-diacetoxy-2-methylenepropane or saponified products thereof; unsaturated acids or their anhydrides, salts, or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; olefin sulfones such as vinylsulfonic acid, allylsulfonic acid and methallylsulfonic acid Acids or salts thereof; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, γ-methacryloxypropylmethoxysilane, etc. Vinylsilane compounds; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, Examples include vinylidene chloride.

EVOH (A) may be post-modified by techniques such as urethanization, acetalization, cyanoethylation, and oxyalkylenation.

When EVOH (A) has other modifying groups such as monomeric units, EVOH (A) may have a structure represented by the following formula (I).

[In formula (I), X represents a hydrogen atom, a methyl group, or a group represented by R ² —OH. R ¹ and R ² each independently represent a single bond, an alkylene group having 1 to 9 carbon atoms, or an alkyleneoxy group having 1 to 9 carbon atoms, and the alkylene group and the alkyleneoxy group are a hydroxyl group, an alkoxy group, or Halogen atoms may also be included. ]

X is preferably a hydrogen atom or a group represented by R ² --OH, more preferably a group represented by R ² --OH.

The alkylene group and alkyleneoxy group used as R ¹ and R ² may contain a hydroxyl group, an alkoxy group or a halogen atom. R ¹ and R ² are preferably C 1-5 alkylene or alkyleneoxy groups, more preferably C 1-3 alkylene or alkyleneoxy groups.

Specific examples of the structure (modifying group) represented by formula (I) include structural units (modifying groups) represented by the following formulas (II), (III), and (IV). be done.

[In formula (II), R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and the alkyl group may contain a hydroxyl group, an alkoxy group or a halogen atom. ]

[In formula (III), R ⁵ has the same definition as X in formula (I). R ⁶ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and the alkyl group may contain a hydroxyl group, an alkoxy group or a halogen atom. ]

[In formula (IV), R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, or a hydroxyl group. Moreover, some or all of the hydrogen atoms of the alkyl group and the cycloalkyl group may be substituted with a hydroxyl group, an alkoxy group, or a halogen atom. ]

In the present invention, R ¹ in formula (I) may be a single bond and X may be a hydroxymethyl group (R ³ and R ⁴ in formula (II) are hydrogen atoms). When EVOH (A) contains the modifying group, the lower limit of the content is preferably 0.1 mol%, more preferably 0.4 mol%, and even more preferably 1.0 mol%. On the other hand, the upper limit of the content of the modifying group is preferably 20 mol%, more preferably 10 mol%, still more preferably 8 mol%, and particularly preferably 5 mol%.

In the present invention, R ¹ in formula (I) may be a hydroxymethylene group and X may be a hydrogen atom (R ⁵ and R ⁶ in formula (III) may be hydrogen atoms). When EVOH (A) contains the modifying group, the lower limit of the content is preferably 0.1 mol%, more preferably 0.4 mol%, and even more preferably 1.0 mol%. On the other hand, the upper limit of the content of the modifying group is preferably 20 mol%, more preferably 10 mol%, still more preferably 8 mol%, and particularly preferably 5 mol%.

In the present invention, R ¹ in formula (I) may be a methylmethyleneoxy group and X may be a hydrogen atom. In addition, the methylmethyleneoxy group has an oxygen atom bonded to a carbon atom of the main chain. That is, in formula (IV), one of R ⁷ and R ⁸ may be a methyl group and the other may be a hydrogen atom. When EVOH (A) contains the modifying group, the lower limit of the content is preferably 0.1 mol%, more preferably 0.5 mol%, further preferably 1.0 mol%, and 2.0 mol%. is particularly preferred. On the other hand, the upper limit of the content of the modifying group is preferably 20 mol%, more preferably 15 mol%, and even more preferably 10 mol%, from the viewpoint of improving plant growth.

EVOH (A) may be used alone or in combination of two or more.

The lower limit of the melt flow rate (MFR) of EVOH (A) at 190° C. and a load of 2160 g, measured according to JIS K7210:1999, is preferably 0.1 g/10 minutes, more preferably 0.5 g/10 minutes. , 1.0 g/10 min. On the other hand, the upper limit of the MFR of EVOH (A) is preferably 30 g/10 minutes, more preferably 20 g/10 minutes, even more preferably 15 g/10 minutes. When the MFR of EVOH (A) at 190° C. and a load of 2160 g is within the above range, the melt moldability is enhanced, and as a result, the long run property tends to be enhanced.

The lower limit of the melting point of EVOH (A) is preferably 135°C, more preferably 150°C, even more preferably 155°C. The upper limit of the melting point of EVOH (A) is preferably 200°C, more preferably 190°C, and even more preferably 185°C. When the melting point of EVOH (A) is 200° C. or lower, the melt moldability is improved, and as a result, the long run property tends to be enhanced.

(EVOH (B))
EVOH (B) is EVOH derived from fossil fuels. Here, EVOH derived from fossil fuel means EVOH synthesized using raw materials derived from fossil fuel. That is, EVOH (B) is EVOH in which all of the raw material monomers ethylene, vinyl ester, and optionally other monomers are derived from fossil fuels. In other words, EVOH (B) is EVOH synthesized without using biomass-derived raw materials. By including EVOH (B) in the resin composition, sufficient long-run properties can be exhibited.

Specific and preferred aspects of EVOH (B) are the same as those of EVOH (A), except that the raw material is derived from fossil fuels, that is, its biobased content is 0%. That is, the specific and preferred ethylene unit content, degree of saponification, type and content derived from other monomers, MFR, melting point, etc. of EVOH (B) are the same as those of EVOH (A).

EVOH (B) may be used alone or in combination of two or more.

In the above form (I) in which EVOH (A) and EVOH (B) are used in combination, the lower limit of the mass ratio (A/B) between EVOH (A) and EVOH (B) is preferably 1/99. /95 is more preferred, 15/85 is even more preferred, and 40/60 is particularly preferred. By setting the mass ratio (A/B) to 1/99 or more, the bio-based degree of the resin composition can be increased and the environmental load can be reduced. From the viewpoint of further reducing the environmental load, the lower limit of the mass ratio (A/B) is preferably 60/40 in some cases, and 75/25 in other cases. Also, the upper limit of the mass ratio (A/B) is preferably 99/1, more preferably 95/5, more preferably 85/15 in some cases, and even more preferably 60/40 or 40/60 in some cases. By setting the mass ratio (A/B) to 99/1 or less, long-run properties can be enhanced.

The ethylene unit content, saponification degree, MFR, melting point, etc. of EVOH (A) and EVOH (B) may be the same or different. From the viewpoint of enhancing performance such as long-run properties, it is preferable that the ethylene unit content, saponification degree, MFR and melting point of EVOH (A) and EVOH (B) are the same or close to each other. The difference in ethylene unit content between EVOH (A) and EVOH (B) is preferably 6 mol % or less, more preferably 3 mol % or less, and even more preferably 0 mol %. The difference in saponification degree between EVOH (A) and EVOH (B) is preferably 2 mol % or less, more preferably 1 mol % or less, and even more preferably 0 mol %. The difference in MFR between EVOH (A) and EVOH (B) is preferably 2 g/10 minutes or less, more preferably 1 g/10 minutes or less, and even more preferably 0 g/10 minutes. The difference in melting point between EVOH (A) and EVOH (B) is preferably 7°C or less, more preferably 3°C or less, and even more preferably 0°C.

(EVOH (A'))
EVOH (A′) is an EVOH in which a part of the raw material monomers ethylene and vinyl ester is derived from biomass, and the rest of the raw material monomers ethylene and vinyl ester is derived from fossil fuels. When the raw material of EVOH (A′) contains a biomass-derived raw material, the degree of bio-basedness in the resin composition is increased, and the environmental load tends to be reduced. In addition, since the raw material of EVOH (A′) contains a raw material derived from fossil fuel, the long-run property of the resin composition can be improved.

EVOH (A') is obtained by saponification of a copolymer of ethylene and vinyl ester, partly derived from biomass and partly derived from fossil fuels. The production and saponification of the ethylene-vinyl ester copolymer, which is the precursor of EVOH (A'), can be carried out by a conventionally known method, except that some of the raw materials are derived from biomass.

Examples of biomass-derived ethylene and biomass-derived vinyl esters used in the synthesis of EVOH (A') are similar to those described above for use in the synthesis of EVOH (A).

Specific and suitable conditions for the ethylene unit content and degree of saponification of EVOH (A') are the same as those for EVOH (A) described above.

In the ethylene and vinyl ester used as raw materials for EVOH (A'), at least part of the ethylene is preferably biomass-derived, and all of the ethylene may be biomass-derived. It is also preferable that at least part of the vinyl ester, which is the raw material of EVOH (A'), is derived from biomass, and all of the vinyl ester may be derived from biomass.

The lower limit of the ratio of biomass-derived vinyl alcohol units in all vinyl alcohol units (saponified vinyl ester units) constituting EVOH (A′) is preferably 1 mol%, more preferably 5 mol%, and 10 mol%. More preferably, 25 mol% or 45 mol% is more preferable, and it may be 70 mol%, 90 mol%, or 99 mol%, and all vinyl alcohol units constituting EVOH (A') are derived from biomass. good too. The upper limit of the ratio of vinyl alcohol units derived from fossil fuels in all vinyl alcohol units constituting EVOH (A') is preferably 99 mol%, more preferably 95 mol%, still more preferably 90 mol%, 75 mol% or 55 mol% is more preferable, and it may be 30 mol%, 10 mol% or 1 mol%, and all vinyl alcohol units constituting EVOH (A') do not contain vinyl alcohol units derived from fossil fuels. may When the proportion of biomass-derived vinyl alcohol units in the total vinyl alcohol units constituting EVOH (A′) increases, the degree of bio-basedness in the resin composition increases, tending to reduce the environmental load. On the other hand, from the viewpoint of providing a resin composition having an excellent balance between bio-based content and long-run properties, the ratio of biomass-derived vinyl alcohol units is preferably 5 mol% or more and 95 mol% or less, and 15 mol% or more and 85 mol% or less. is more preferable, 25 mol % or more and 75 mol % or less is still more preferable, and 35 mol % or more and 65 mol % or less is particularly preferable.

The lower limit of the ratio of biomass-derived ethylene in all ethylene units constituting EVOH (A′) is preferably 1 mol%, more preferably 5 mol%, still more preferably 10 mol%, and 25 mol% or 45 mol%. More preferably, it may be 70 mol %, 90 mol % or 99 mol %, and all ethylene units constituting EVOH (A′) may be derived from biomass. The upper limit of the ratio of fossil fuel-derived ethylene units in all ethylene units constituting EVOH (A') is preferably 99 mol%, more preferably 95 mol%, further preferably 90 mol%, 75 mol% or 55 mol % is even more preferable, and may be 30 mol %, 10 mol %, or 1 mol %, and ethylene units derived from fossil fuels may not be contained in all ethylene units constituting EVOH (A'). . When the proportion of biomass-derived ethylene units in the total ethylene units constituting EVOH (A′) increases, the resin composition of the present invention has a higher degree of bio-based content, which tends to reduce the environmental load. On the other hand, from the viewpoint of providing a resin composition having an excellent balance between biobased content and long-run properties, the ratio of biomass-derived ethylene units is preferably 5 mol% or more and 95 mol% or less, and 15 mol% or more and 85 mol% or less. It is more preferably 25 mol % or more and 75 mol % or less, and particularly preferably 35 mol % or more and 65 mol % or less.

The lower limit of the biobased content of EVOH (A') is preferably 1%, more preferably 5%, even more preferably 20%, and particularly preferably 40%, from the viewpoint of reducing the environmental load of the resin composition. Further, in applications where, for example, particularly excellent long-run properties are not required, the lower limit of the biobased content of EVOH (A') may be 60% or 80%. On the other hand, the upper limit of the biobased content of EVOH (A') is preferably 99%, more preferably 95%, and even more preferably 85%, 75% or 65% from the viewpoint of good long-run properties.

EVOH (A') may have units derived from monomers other than ethylene, vinyl esters and saponified products thereof, and may be post-modified, as long as the object of the present invention is not hindered. . Specific examples of copolymerization components and post-modification are the same as those of EVOH (A) described above.

EVOH (A') may be used alone or in combination of two or more.

Preferred aspects of the melt flow rate (MFR) and melting point of EVOH (A′) at 190° C. and a load of 2160 g, measured according to JIS K7210:1999, are the same as those of EVOH (A) described above.

The lower limit of the proportion of one or more EVOH in all resins constituting the resin composition is preferably 80% by mass, more preferably 90% by mass, still more preferably 95% by mass, and particularly preferably 98% by mass. , 99% by mass, and the resin constituting the resin composition may be substantially only one or two or more EVOH, or may be one or two or more EVOH. The lower limit of the ratio of one or more EVOH in the resin composition is preferably 80% by mass, more preferably 90% by mass, even more preferably 95% by mass, particularly preferably 98% by mass, and 99% by mass. and the resin composition may consist essentially of one or more EVOH.

The lower limit of the total biobased content of one or more EVOH contained in the resin composition is preferably 1%, more preferably 5%, and even more preferably 20%, from the viewpoint of reducing the environmental load of the resin composition. 40% is particularly preferred. Moreover, in applications where, for example, particularly excellent long-run properties are not required, the lower limit of the biobased content of the entire EVOH may be 60% or 80%. On the other hand, the upper limit of the biobased content of the entire EVOH is preferably 99%, more preferably 95%, 85%, 75%, 65%, 55%, 45%, 35% or 25% may be even more preferred.

The specific and preferred ranges of the ethylene unit content, saponification degree, MFR and melting point of the one or more EVOHs contained in the resin composition are the same as those of the EVOH (A) described above.

It is more preferable that the resin composition contains more than 0 ppm and not more than 100 ppm of sulfur compounds in terms of sulfur atoms from the viewpoint of tracking in-house products. In addition, the inventors have found that sulfur compounds of 100 ppm or less in terms of sulfur atoms do not substantially affect the performance of the resin composition used in the medium for plant cultivation, and sulfur compounds are used as tracer substances. preferred. The upper limit of the sulfur compound content is more preferably 50 ppm, more preferably 5 ppm, even more preferably 3 ppm, and particularly preferably 0.3 ppm. The lower limit of the sulfur compound content may be 0.0001 ppm, 0.001 ppm, 0.01 ppm, 0.05 ppm, or 0.1 ppm. When biomass-derived raw materials are used, EVOH containing organic sulfur compounds contained in the biomass raw materials may be obtained. On the other hand, fossil fuel-derived EVOH is desulfurized during cracking of naphtha, so sulfur compounds are less than biomass-derived EVOH. Therefore, when such biomass-derived EVOH is used, it becomes easier to trace the biomass-derived EVOH by comparing the sulfur compound content. In particular, when the gas barrier resin composition contains an organic sulfur compound, especially dimethylsulfide or dimethylsulfoxide, as the sulfur compound, tracking becomes easier. In addition, from the perspective of tracking our own products, when manufacturing EVOH, the content of sulfur compounds in the biomass-derived ethylene and biomass-derived vinyl ester, which are raw materials, and the resulting EVOH, is below the detection limit. It may be preferable not to over-purify as follows.

(Other ingredients)
Preferably, the resin composition further contains a carboxylic acid. When the resin composition contains a carboxylic acid, it is possible to improve melt moldability and coloring resistance at high temperatures.

When the resin composition contains carboxylic acid, the lower limit of the content is preferably 30 ppm, more preferably 100 ppm, in terms of carboxylic acid radical. On the other hand, the upper limit of the carboxylic acid content is preferably 1000 ppm, more preferably 600 ppm. When the carboxylic acid content is 30 ppm or more, the coloration resistance at high temperatures tends to be good. On the other hand, when the carboxylic acid content is 1000 ppm or less, the melt moldability tends to be good. The content of carboxylic acid is calculated by titrating an extract obtained by extracting 10 g of the resin composition with 50 ml of pure water at 95° C. for 8 hours. Here, as the content of carboxylic acid in the resin composition, the content of carboxylate present in the extract is not considered. Also, the carboxylic acid may exist as a carboxylic acid ion.

Carboxylic acids include monovalent carboxylic acids and polyvalent carboxylic acids, which may consist of one or more. When both a monovalent carboxylic acid and a polyvalent carboxylic acid are included as the carboxylic acid, the melt moldability of the resin composition and the coloration resistance at high temperatures may be further improved. Also, the polyvalent carboxylic acid may have 3 or more carboxy groups. In this case, it may be possible to further improve the coloring resistance of the resin composition.

A monovalent carboxylic acid is a compound having one carboxy group in the molecule. The pKa of the monovalent carboxylic acid is preferably in the range of 3.5-5.5. Examples of such monovalent carboxylic acids include formic acid (pKa = 3.77), acetic acid (pKa = 4.76), propionic acid (pKa = 4.85), butyric acid (pKa = 4.82), and caproic acid. (pKa = 4.88), capric acid (pKa = 4.90), lactic acid (pKa = 3.86), acrylic acid (pKa = 4.25), methacrylic acid (pKa = 4.65), benzoic acid ( pKa=4.20) and 2-naphthoic acid (pKa=4.17). These carboxylic acids may have substituents such as hydroxyl groups, amino groups and halogen atoms as long as the pKa is in the range of 3.5 to 5.5. Among them, acetic acid is preferred because of its high safety and ease of handling.

A polyvalent carboxylic acid is a compound having two or more carboxy groups in the molecule. In this case, the pKa of at least one carboxyl group is preferably in the range of 3.5 to 5.5. Examples of such polyvalent carboxylic acids include oxalic acid (pKa2 = 4.27), succinic acid (pKa1 = 4.20), fumaric acid (pKa2 = 4.44), malic acid (pKa2 = 5.13), Glutaric acid (pKa1 = 4.30, pKa2 = 5.40), adipic acid (pKa1 = 4.43, pKa2 = 5.41), pimelic acid (pKa1 = 4.71), phthalic acid (pKa2 = 5.41 ), isophthalic acid (pKa2 = 4.46), terephthalic acid (pKa1 = 3.51, pKa2 = 4.82), citric acid (pKa2 = 4.75), tartaric acid (pKa2 = 4.40), glutamic acid (pKa2 = 4.07) and aspartic acid (pKa = 3.90).

The resin composition preferably further contains a phosphoric acid compound. When the resin composition contains a phosphoric acid compound, the lower limit of the content is preferably 1 ppm, more preferably 3 ppm in terms of phosphate radical. On the other hand, the upper limit of the content is preferably 200 ppm, more preferably 100 ppm in terms of phosphate radical. When the phosphoric acid compound is contained within this range, the thermal stability of the resin composition may be improved. In particular, it may be possible to suppress the generation of gel-like lumps and coloration during melt molding over a long period of time. As the phosphoric acid compound, for example, various acids such as phosphoric acid and phosphorous acid, salts thereof, and the like can be used. The phosphate may be in the form of primary phosphate, secondary phosphate, or tertiary phosphate. Cationic species of phosphate include alkali metals and alkaline earth metals. Specific examples of the phosphoric acid compound include sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate.

The resin composition preferably further contains a boron compound. When the resin composition contains a boron compound, the lower limit of its content is preferably 5 ppm, more preferably 100 ppm, in terms of boron atoms. On the other hand, the upper limit of the content is preferably 5000 ppm, more preferably 1000 ppm, in terms of boron atoms. When the boron compound is contained within this range, the thermal stability of the resin composition during melt molding can be improved, and the occurrence of gel-like lumps can be suppressed in some cases. In addition, the mechanical properties of the obtained molded article can be improved in some cases. These effects are presumed to be due to the occurrence of chelate interactions between EVOH and boron compounds. Boron compounds include, for example, boric acid, borate esters, borates, and borohydride. Specifically, boric acid includes, for example, orthoboric acid (H ₃ BO ₃ ), metaboric acid, and tetraboric acid, and boric acid esters include, for example, trimethyl borate and triethyl borate. Examples of salts include alkali metal salts, alkaline earth metal salts, and borax of the above boric acids.

The resin composition preferably further contains metal ions. By controlling the content ratio of the metal ion and the carboxylic acid described above, the melt moldability and color resistance of the resin composition can also be improved.

When the resin composition contains metal ions, the lower limit of the content is preferably 1 ppm, more preferably 100 ppm, and even more preferably 150 ppm. On the other hand, the upper limit of the metal ion content is preferably 1000 ppm, more preferably 400 ppm, and even more preferably 350 ppm. When the metal ion content is 1000 ppm or less, the color resistance tends to be good.

Metal ions include monovalent metal ions, divalent metal ions, and other transition metal ions, which may consist of one or more. Among them, monovalent metal ions and divalent metal ions are preferred.

The monovalent metal ion is preferably an alkali metal ion such as lithium, sodium, potassium, rubidium and cesium ions, and sodium or potassium ions are preferred from the viewpoint of industrial availability. Alkali metal salts that give alkali metal ions include, for example, aliphatic carboxylates, aromatic carboxylates, carbonates, hydrochlorides, nitrates, sulfates, phosphates and metal complexes. Among them, aliphatic carboxylates and phosphates are preferred because they are readily available, and specifically, sodium acetate, potassium acetate, sodium phosphate and potassium phosphate are preferred.

In some cases it may be preferred to include divalent metal ions as metal ions. If the metal ions contain divalent metal ions, for example, thermal deterioration of EVOH may be suppressed when the trim is recovered and reused, and the formation of gels and lumps in the resulting molded article may be suppressed. Examples of divalent metal ions include ions of beryllium, magnesium, calcium, strontium, barium and zinc, and ions of magnesium, calcium or zinc are preferred from the standpoint of industrial availability. Examples of divalent metal salts that give divalent metal ions include carboxylates, carbonates, hydrochlorides, nitrates, sulfates, phosphates and metal complexes, with carboxylates being preferred. The carboxylic acid constituting the carboxylate is preferably a carboxylic acid having 1 to 30 carbon atoms, and specific examples include acetic acid, stearic acid, lauric acid, montanic acid, behenic acid, octylic acid, sebacic acid, ricinoleic acid, Examples include myristic acid and palmitic acid, and among them, acetic acid and stearic acid are preferred.

The resin composition includes, for example, antiblocking agents, processing aids, resins other than EVOH, stabilizers, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, as long as the effects of the present invention are not impaired. Other components such as lubricants, coloring agents, fillers, surfactants, desiccants, oxygen absorbers, cross-linking agents, and reinforcing agents such as various fibers may be contained.

The antiblocking agent includes oxides, nitrides, oxynitrides, etc. of elements selected from silicon, aluminum, magnesium, zirconium, cerium, tungsten, molybdenum, etc. Among these, silicon oxide is preferable from the viewpoint of easy availability. . Blocking resistance can be improved because the resin composition contains an antiblocking agent.

Processing aids include fluorine-based processing aids such as Kynar (registered trademark) manufactured by Arkema and Dynamer (registered trademark) manufactured by 3M. When the resin composition contains a processing aid, it tends to prevent adhesion of eye mucus to the die lip.

Examples of resins other than EVOH include various polyolefins (polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymers, copolymers of ethylene and α-olefins having 4 or more carbon atoms. Copolymers of polyolefins and maleic anhydride, ethylene-vinyl ester copolymers, ethylene-acrylic acid ester copolymers, or modified polyolefins obtained by graft-modifying these with unsaturated carboxylic acids or derivatives thereof, etc.), various Polyamide (nylon 6, nylon 6.6, nylon 6/66 copolymer, nylon 11, nylon 12, poly-metaxylylene adipamide, etc.), various polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), poly Examples include vinyl chloride, polyvinylidene chloride, polystyrene, polyacrylonitrile, polyurethane, polycarbonate, polyacetal, polyacrylate and modified polyvinyl alcohol resins.

Stabilizers for improving melt stability include hydrotalcite compounds, hindered phenol-based and hindered amine-based heat stabilizers, metal salts of higher aliphatic carboxylic acids (e.g., calcium stearate, magnesium stearate, etc.), and the like. is mentioned. When the resin composition contains a stabilizer, its content is preferably 0.001 to 1% by mass.

Antioxidants include 2,5-di-t-butyl-hydroquinone, 2,6-di-t-butyl-p-cresol, 4,4′-thiobis-(6-t-butylphenol), 2,2 '-methylene-bis-(4-methyl-6-t-butylphenol), octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, 4,4'-thiobis- (6-t-butylphenol) and the like.

UV absorbers include ethylene-2-cyano-3′,3′-diphenyl acrylate, 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(2′-hydroxy-3′-t -Butyl-5′-methylphenyl)5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone and the like.

Examples of plasticizers include dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, and phosphate.

Antistatic agents include pentaerythrityl monostearate, sorbitan monopalmitate, sulfated polyolefins, polyethylene oxide, carbowax and the like.

Lubricants include ethylenebisstearamide, butyl stearate and the like.

Examples of coloring agents include carbon black, phthalocyanine, quinacridone, indoline, azo pigments, and red iron oxide.

Fillers include glass fiber, asbestos, ballastonite, calcium silicate and the like.

Examples of desiccants include phosphates (excluding the above phosphates), sodium borate, sodium sulfate, sodium chloride, sodium nitrate, sugar, silica gel, bentonite, molecular sieves, super absorbent resins, and the like.

The resin composition may contain impurities derived from biomass due to EVOH (A) or EVOH (A'). Although various impurities may be contained, at least metals such as iron and nickel tend to be contained in large amounts in many cases.

(Bio-based content of resin composition)
The lower limit of the biobased content of the resin composition is preferably 1%, more preferably 5%, even more preferably 20%, and particularly preferably 40%, from the viewpoint of reducing environmental load. Moreover, in applications where, for example, particularly excellent long-run properties are not required, the lower limit of the biobased content of the resin composition may be 60% or 80%. On the other hand, the upper limit of the biobased content of the resin composition is preferably 99%, more preferably 95%, 85%, 75%, 65%, 55%, 45%, 35%, or 25% may be even more preferred. The biobased content of the resin composition refers to a value measured in consideration of other resins and the like contained in optional components other than EVOH.

(Method for producing resin composition)
The method for producing the resin composition is not particularly limited. For example, in the case of a resin composition containing EVOH (A) and EVOH (B),
(1) A method of mixing (dry blending) pellets of EVOH (A), pellets of EVOH (B), and, if necessary, other components described above, and melt-kneading the mixed pellets;
(2) After immersing the EVOH (A) pellets and/or the EVOH (B) pellets in a solution containing the above-mentioned other components as necessary, the EVOH (A) pellets and the EVOH (B) a method of dry-blending the pellets and melt-kneading them;
(3) EVOH (A) pellets and EVOH (B) pellets are dry-blended, and when these are melt-kneaded, an aqueous solution containing the above-mentioned other components is added as necessary in the middle of the extruder. Method (4) A method of blending a molten resin of EVOH (A) and a molten resin of EVOH (B) in a molten state (other components may be included in EVOH (A) and/or EVOH (B) in advance, if necessary). It may be left alone or liquid-added in the extruder)
etc.

According to the above production methods (1) to (4), etc., the mixing ratio of EVOH (A) and EVOH (B) is adjusted according to the application, performance, etc. It is possible to produce a resin composition capable of molding a molded body for a plant cultivation medium having high plant growth while taking into account the balance between and. Among these, it is preferable to include (1) a step of dry-blending pellets of EVOH (A) and pellets of EVOH (B) and melt-kneading them. A ribbon blender, a high-speed mixer-co-kneader, a mixing roll, an extruder, an intensive mixer, or the like can be used for mixing the pellets with each other or mixing the pellets with other components.

Further, in the case of a resin composition containing EVOH (A'), EVOH (A') is synthesized by a known method, and the obtained EVOH (A') is subjected, if necessary, to other It can be produced by mixing the components.

[Molded product, method of use, etc.]
The form of the molded body contained in the plant cultivation medium of the present invention is not particularly limited as long as it is formed from the resin composition. The molded article is usually a melt-molded article of the resin composition. The molded article may be a chip (pellet) made of the resin composition, a non-woven fabric made of the resin composition, or the like. From the viewpoint of plant growth efficiency, the chip (resin composition chip) made of the above resin composition is preferable. In this case, for example, a large number of chips can be spread over a container or the like and used as a plant cultivation medium.

The chip (resin composition chip) has, for example, a substantially spherical or disk-like shape obtained by hot-cutting a melt of the resin composition, or a shape obtained by cutting a strand of the resin composition. The shape obtained may be a substantially cylindrical shape, or may be a flake shape or an irregular shape. The chips are preferably columnar, flat or flake-shaped.

Also, the size of the molded body such as the chip is not particularly limited. The maximum length can be measured using vernier calipers.

W1 is the weight of the molded body after it has been immersed in water at 23°C for 24 hours, and W0 is the weight after drying the molded body after the immersion (dried at 105°C for 24 hours). The water absorption defined by the following formula (1) is preferably 5% by mass or more, more preferably 10% by mass or more. When the water absorption rate is within the above range, a plant cultivation medium having excellent water retention can be obtained. Although there is no particular upper limit for the water absorption rate, it is preferably 300% by mass or less from the viewpoint of the strength of the molded article.
Water absorption (mass%) = 100 × (W1-W0) / W0 (1)

The medium for cultivating plants of the present invention may be composed only of a molded article made of the above resin composition, but the molded article made of the above resin composition may also include rock wool, sand, soil, ceramic balls, coconut shells, and bark. , peat moss, sphagnum moss, and other resin media. The content of the molded article in the plant cultivation medium of the present invention is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 95% by mass or more.

There are no particular restrictions on the mode of use of the medium for plant cultivation of the present invention, but it is preferably used as a medium for hydroponics using a culture solution. When the medium for plant cultivation of the present invention is used as a medium for hydroponic cultivation, the method of use is, for example, by placing the medium for plant cultivation of the present invention in a container such as a pot and adding a culture solution thereto. A method of sowing or transplanting seedlings can be exemplified later. Another example is a method of preparing a cultivation bed on which the plant cultivation medium of the present invention is spread and transplanting grown seedlings to cultivate various crops.

There are no particular restrictions on the types of plants that can be cultivated using the plant cultivation medium of the present invention. It is preferably used for growing vegetables such as tomatoes, eggplants and peppers. In particular, there is also the advantage that it can be suitably used for root crops that are difficult to cultivate with rock wool.

<Plant cultivation device>
The present invention also provides a plant cultivating apparatus comprising the plant cultivating medium of the present invention described above. The plant cultivation apparatus of the present invention is not particularly limited as long as it uses the above-described plant cultivation medium of the present invention. may have a configuration of

FIG. 1 is a diagram schematically showing a plant cultivation device 1 as a preferred example of the present invention. A plant cultivating apparatus 1 of the example shown in FIG. Water containing nutrients (nutrient solution) 6 is stored up to a height (depth) to the extent that it does not spill out. A shelf 8 is provided on the bottom wall 7 of the planter 2 so that its mounting surface 8a is arranged above the surface of the water 6, and the water absorbent sheet 9 is placed on the shelf 8 so that the planter can be seen from above. It is provided so as to cover most of the bottom wall 7 of 2. The water absorbent sheet 9 is a sheet-like article made of a material such as cellulose fiber, nylon fiber, vinylon fiber, polyester fiber, polyolefin fiber, rayon fiber, aramid fiber, glass fiber, etc. and is provided so that its end 9b is immersed in the water 6 in the planter 2, and is configured to send the water 6 absorbed from the end 9b to the central portion 9a. .

In the example shown in FIG. 1, a root-proof and water-permeable sheet 10 is placed on the water-absorbing sheet 9 so that the edge 10a of the sheet 10 is caught on the upper end 4a of the side wall 4 of the planter 2 . The root permeable sheet 10 is preferably provided when root vegetables are grown in the plant cultivation apparatus 1, and does not necessarily have to be provided when the plants 11 to be grown are not root vegetables. When such a root permeable sheet 10 is provided, the water 6 in the planter 2 is sent to the root permeable sheet 10 via the water absorbing sheet 9 .

The root permeable sheet 10 is made of fibrous woven fabric, nonwoven fabric, mat-like material, or various polyolefins (polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl alcohol copolymer, ethylene- Vinyl ester copolymers, ethylene-acrylic acid ester copolymers, or modified polyolefins modified with unsaturated carboxylic acids, graft-modified with their derivatives, or modified with maleic anhydride, etc.), various nylons (nylon-6 , nylon-66, nylon-6/66 copolymer, etc.), polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyacrylonitrile, polyurethane, polyacetal and modified polyvinyl alcohol. , which is permeable, flexible, and impervious to roots. When a sheet made of the above resin is used as the root-proof and water-permeable sheet 10, it preferably has numerous micropores with a uniform distribution. In this case, the maximum diameter of the micropores is preferably 20 μm or less. By setting the maximum diameter of the micropores to 20 μm or less, the roots of the plant penetrate the root-proof water-permeable sheet 10 and enter the water-absorbing sheet 9, making it difficult for them to cling to the water-absorbing sheet 9. grow better. In addition, by setting the maximum diameter of the micropores to, for example, 5 μm or more, water is easily exuded from the water-absorbing sheet, and the growth of plants is improved. Since such a root permeable sheet 10 has a fine mesh, it has a property that it is difficult for water to pass therethrough and water is easily retained.

In the example shown in FIG. 1, the above-described plant cultivation medium 12 of the present invention is placed on a root-proof and water-permeable sheet 10, and a plant 11 is grown therein. FIG. 4 shows an example in which a plurality of cylindrical pellets (resin composition chips) 13 formed from the resin composition are used as the plant cultivation medium 12 of the present invention.

<Plant Cultivation Method>
The present invention also provides a method for cultivating plants using the medium for cultivating plants of the present invention described above. That is, the plant cultivation method of the present invention is a plant cultivation method comprising a step of cultivating using the plant cultivation medium of the present invention. In the plant cultivation method of the present invention, when the above-described plant cultivation medium of the present invention is used as a medium for hydroponics, for example, the plant cultivation medium of the present invention is placed in a container such as a pot, and the culture solution is added to the container. A method of sowing or transplanting seedlings after addition can be exemplified. Another example is a method of preparing a cultivation bed on which the plant cultivation medium of the present invention is spread and transplanting grown seedlings to cultivate various crops.

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

[Evaluation method]
(1) Ethylene Unit Content and Saponification Degree of EVOH For the EVOH pellets obtained by synthesis and the resin composition pellets obtained in Examples and Comparative Examples, tetramethylsilane was used as an internal standard and tetrafluoro was used as an additive. Dissolved in dimethyl sulfoxide (DMSO)-d ⁶ containing acetic acid (TFA), measured at 80 ° C. using 500 MHz 1H-NMR ("JMTC-400/54/SS" manufactured by JEOL Ltd.), ethylene unit Content and degree of saponification were measured.
Each peak in the spectrum of the above measurements is assigned as follows.
0.6-1.9 ppm: methylene proton (4H) of ethylene unit, methylene proton (2H) of vinyl alcohol unit, methylene proton (2H) of vinyl acetate unit
1.9-2.0 ppm: methyl proton (3H) of vinyl acetate unit
3.1-4.2 ppm: vinyl alcohol unit methine proton (1H)

(2) Quantitative determination of carboxylic acid 20 g of the synthesized EVOH pellets or the resin composition pellets obtained in Examples and Comparative Examples and 100 mL of ion-exchanged water were put into a 200 mL Erlenmeyer flask with a common stopper, and the cooling condenser was placed. and extracted with stirring at 95° C. for 6 hours. The resulting extract was subjected to neutralization titration with N/50 NaOH using phenolphthalein as an indicator to quantify the content of carboxylic acid in terms of carboxylic acid group. In addition, in the embodiment containing a phosphorus compound, the amount of carboxylic acid was calculated in consideration of the content of the phosphorus compound measured by the evaluation method described later.

(3) Quantification of Metal Ions, Phosphate Compounds, and Boron Compounds 0.5 g of the synthesized EVOH pellets or the resin composition pellets obtained in Examples and Comparative Examples were placed in a Teflon (registered trademark) pressure vessel. , 5 mL of concentrated nitric acid was added thereto and decomposed at room temperature for 30 minutes. After 30 minutes, the lid was closed, and decomposition was performed by heating at 150° C. for 10 minutes and then at 180° C. for 5 minutes using a wet decomposition apparatus (“MWS-2” manufactured by Actac Co.), and then cooled to room temperature. This treatment liquid was transferred to a 50 mL volumetric flask (manufactured by TPX) and diluted with pure water. This solution is subjected to elemental analysis using an ICP emission spectrometer ("OPTIMA4300DV" by PerkinElmer), and the amount of metal ions in terms of metal atoms and the amount of phosphorus compounds in terms of phosphorus atoms contained in the EVOH pellets or resin composition pellets. And the boron atom equivalent amount of the boron compound was determined.

(4) Degree of bio-based The EVOH pellets obtained by synthesis and the resin composition pellets obtained in Examples and Comparative Examples were subjected to radioactive carbon analysis using an accelerator mass spectrometer (AMS) according to the method described in ASTM D6866-18. The concentration of ( ¹⁴ C) was measured and the biobased content was calculated based on the principle of radiocarbon dating.

(5) Long-run evaluation When producing resin composition pellets in Examples and Comparative Examples, melt extrusion with a twin-screw extruder was continuously operated for a long time to evaluate long-term operation stability (long-run). .

(5-1) Die deposit adhesion amount The strand die and the resulting pellets are visually observed every 30 minutes after the start of melt extrusion of the resin composition pellets according to the following evaluation criteria, deposits adhering to the strand die Die deposit removal was performed according to the amount of . Long-run property was evaluated by implementing this continuously for 24 hours. If the strand was cut before being cut by the pelletizer (hereinafter sometimes referred to as "strand breakage"), the surface of the strand die was quickly cleaned, and the operation was restarted.
(Determination Criteria for Die Deposit Amount)
Good (A): The amount of die deposits is slight, and if the die deposits are removed at an interval of 1 hour or longer, no fiber breakage and adhesion of the die deposits to the pellets occur.
Fairly good (B): Die deposits are present, and if the die deposits are not removed at intervals of 30 minutes, fiber breakage or adherence of die deposits to pellets will occur.
Poor (C): Significant amount of die deposits, removal of die deposits at 30 minute intervals still causes breaks or degraded deposits on the pellets.

(5-2) Frequency of yarn breakage The frequency of yarn breakage was observed according to the following evaluation criteria.
(Criteria for paper breakage frequency)
Good (A): The number of yarn breaks is 0 to 2 Fairly good (B): The number of yarn breaks is 3 to 10 Bad (C): The number of yarn breaks is 11 or more

(6) Culture medium evaluation On April 17, 2019, 15 holes were bored in the obtained plant culture medium at intervals of 7 cm in width and 8 cm in length, and 3 seeds of radish 'Tanshin' were directly sown per hole. Thinning was performed on April 27, 2019, and watering was performed about 3 to 6 times a day, depending on the weather and growth conditions. Fertilizers for hydroponics "Otsuka House No. 1", "Otsuka House No. 2" and "Otsuka House No. 5" were mixed and dissolved in a nutrient solution (N: 98.7 ppm, P: 19.4 ppm, K: 125.7 ppm, Ca: 63.0 ppm, Mg: 13.4 ppm, Mn: 0.709 ppm, B: 0.487 ppm, Fe: 2.025 ppm, Cu: 0.018 ppm, Zn: 0.048 ppm, Mo: 0.019 ppm). , The harvest survey was conducted on June 25, 2019. In the harvest survey, the number of radishes with 1 g or more of enlarged roots was counted in 15 wells where the roots were grown.

[Preparation of Vinyl Acetate Synthesis Catalyst]
23 g (water absorption 19.7 g) of silica spherical carrier HSV-I (sphere diameter 5 mm, specific surface area 160 m / g, water absorption 0.75 g / g) manufactured by Shanghai Haiyuan Chemical Technology Co., Ltd., 56% by mass of sodium tetrachloropalladate After being impregnated with an aqueous solution corresponding to the water absorption amount of the carrier containing 1.5 g of an aqueous solution and 1.5 g of a 17 mass% tetrachloroauric acid tetrahydrate aqueous solution, it is immersed in 40 mL of an aqueous solution containing 2.5 g of sodium metasilicate nonahydrate. and allowed to stand for 20 hours. Subsequently, 3.3 mL of a 52% by mass hydrazine hydrate aqueous solution was added, left at rest for 4 hours at room temperature, washed with water until chloride ions disappeared, and dried at 110° C. for 4 hours. The resulting palladium/gold/carrier composition was immersed in 60 mL of a 1.7% by mass acetic acid aqueous solution and allowed to stand overnight. Then, it was washed with water overnight and dried at 110° C. for 4 hours. After that, it was impregnated with an aqueous solution of 2 g of potassium acetate corresponding to the amount of water absorbed by the carrier, and dried at 110° C. for 4 hours to obtain a vinyl acetate synthesis catalyst.

[Synthesis of Vinyl Acetate]
<Synthesis example of VAM1>
3 mL of the above vinyl acetate synthesis catalyst was diluted with 75 mL of glass beads and filled into a SUS316L reaction tube (inner diameter: 22 mm, length: 480 mm). A gas mixed at a ratio of 3/6.1/5.6/26.3/14.7 (mol %) was flowed at a flow rate of 20 NL/hour to carry out a reaction to synthesize vinyl acetate (VAM1). For ethylene, biomass-derived ethylene (manufactured by Braskem SA, sugar cane-derived bioethylene) was used, and a gas cylinder filled with this ethylene (ethylene purity 96.44%, internal volume 29.502 L, internal pressure 1.8234 MPa )It was used. As the acetic acid, biomass-derived acetic acid (manufactured by Godavari Biorefineries Ltd., sugar cane-derived bioacetic acid) was used, which was vaporized at 220° C. and then introduced into the reaction system as steam.

<Synthesis of VAM2 to VAM4>
As shown in Table 1, vinyl acetates VAM2 to VAM4 were synthesized in the same manner as VAM1, except that the raw materials ethylene and acetic acid were changed to those derived from biomass and/or fossil fuels.

In addition, the following raw materials were used as the raw materials used for synthesizing vinyl acetate.
- Biomass-derived ethylene: Braskem S.; A. Bioethylene derived from sugarcane, ethylene derived from fossil fuel: Air Liquide Industrial Gas Co., Ltd., ethylene derived from fossil fuel, acetic acid derived from biomass: Godavari Biorefineries Ltd. Bio acetic acid derived from sugarcane, acetic acid derived from fossil fuels: FUJIFILM Wako Pure Chemical Industries, Ltd., acetic acid derived from fossil fuels

[Synthesis of EVOH]
<Preparation of EVOH (A1) pellet>
(Polymerization of ethylene-vinyl acetate copolymer)
A 250 L pressure reactor equipped with a jacket, a stirrer, a nitrogen inlet, an ethylene inlet, and an initiator addition port was charged with 105 kg of VAM1 and 32.3 kg of methanol (hereinafter sometimes referred to as MeOH) at 65°C. After the temperature was raised to , the inside of the reaction vessel was replaced with nitrogen by bubbling nitrogen for 30 minutes. Then, ethylene was introduced under pressure so that the reactor pressure (ethylene pressure) was 3.67 MPa. As the ethylene, biomass-derived ethylene (manufactured by Braskem SA, sugarcane-derived bioethylene) was used. After adjusting the temperature in the reactor to 65° C., 16.8 g of 2,2′-azobis(2,4-dimethylvaleronitrile) (“V-65” from Wako Pure Chemical Industries, Ltd.) was added as an initiator to methanol. added as a solution to initiate polymerization. The ethylene pressure was maintained at 3.67 MPa and the polymerization temperature at 65° C. during the polymerization. After 3 hours, when the conversion of VAc reached 45%, the mixture was cooled to terminate the polymerization. After the reactor was opened to deethyleneize, nitrogen gas was bubbled through to completely deethylenize. After removing unreacted VAc under reduced pressure, MeOH was added to the ethylene-vinyl acetate copolymer to obtain a 20 mass % MeOH solution.

(saponification and washing)
250 kg of the obtained 20 mass % MeOH solution of the ethylene-vinyl acetate copolymer jacket was placed in a 500 L reaction vessel equipped with a stirrer, nitrogen inlet, reflux condenser and solution addition port, and nitrogen was blown into the solution for 60 minutes. C. and 4 kg of sodium hydroxide was added as a 2N MeOH solution. After the addition of sodium hydroxide was completed, the system was stirred for 2 hours while maintaining the temperature of the system at 60°C to advance the saponification reaction. After 2 hours had passed, 4 kg of sodium hydroxide was again added in the same manner, and heating and stirring were continued for 2 hours. After that, 14 kg of acetic acid was added to stop the saponification reaction, and 50 kg of ion-exchanged water was added. While heating and stirring, MeOH and water were distilled out of the reaction vessel to concentrate the reaction solution. After 3 hours, 50 kg of ion-exchanged water was added to precipitate EVOH. The precipitated EVOH was collected by decantation and pulverized with a mixer. The obtained EVOH powder was put into a 1 g/L acetic acid aqueous solution (bath ratio: 20: ratio of 10 kg of powder to 200 L of ion-exchanged water) and washed with stirring for 2 hours. This was deliquored, further put into a 1 g/L acetic acid aqueous solution (bath ratio: 20), and washed with stirring for 2 hours. The deliquored product was put into ion-exchanged water (bath ratio: 20), stirred and washed for 2 hours, and the deliquoring operation was repeated three times for purification. By drying this at 60° C. for 16 hours, 25 kg of crude dried EVOH was obtained.

(Production of EVOH hydrous pellets)
25 kg of the crude dried EVOH thus obtained was placed in a 100 L stirring vessel equipped with a jacket, a stirrer and a reflux condenser. This solution is extruded through a glass tube with a diameter of 3 mm into a mixed solution of water/MeOH=90/10 at a weight ratio cooled to 5° C. to precipitate in the form of strands, and the strands are cut into pellets with a strand cutter. to obtain hydrous pellets of EVOH. The water-containing EVOH pellets were put into an acetic acid aqueous solution having a concentration of 1 g/L (bath ratio: 20) and washed with stirring for 2 hours. This was deliquored, further put into a 1 g/L acetic acid aqueous solution (bath ratio: 20), and washed with stirring for 2 hours. After dewatering, the aqueous acetic acid solution was renewed and the same operation was performed. After washing with an acetic acid aqueous solution and then deliquoring, the product is put into ion-exchanged water (bath ratio: 20), stirred and washed for 2 hours, and deliquoring is repeated three times for purification. A hydrous pellet of EVOH was obtained from which the residue and the MeOH used in strand precipitation were removed. The moisture content of the obtained EVOH hydrous pellets was measured with a halogen moisture meter "HR73" manufactured by Mettler Co., Ltd., and found to be 110% by mass.

(Production of EVOH (A1) pellets)
The resulting water-containing EVOH pellets were put into an aqueous solution (bath ratio: 20) containing sodium acetate, acetic acid, phosphoric acid and boric acid, and immersed for 4 hours with periodic stirring. The concentration of each component was adjusted so that the content of each component in the obtained EVOH (A1) pellets was as shown in Table 2. EVOH (A1) pellets containing sodium acetate, acetic acid, phosphoric acid and boric acid were obtained by deliquoring after immersion and drying in air at 80°C for 3 hours and in air at 130°C for 7.5 hours. rice field.

<Production of pellets of EVOH (A2) to EVOH (A9) and EVOH (B1) to EVOH (B4)>
EVOH (A2) pellets were prepared in the same manner as for EVOH (A1) pellets, except that the types of ethylene and vinyl acetate as raw materials (raw material monomers) and the contents of phosphoric acid compounds and boron compounds were changed as shown in Table 2. ~ EVOH (A9) pellets and EVOH (B1) ~ EVOH (B4) pellets were produced. Ethylene manufactured by Air Liquide Industrial Gas Co., Ltd. was used as ethylene derived from fossil fuel.

For each of EVOH (A1) pellets to EVOH (A9) pellets and EVOH (B1) to EVOH (B4) pellets, the ethylene unit content and saponification degree are determined according to the methods described in the above evaluation methods (1) to (4). , quantification of carboxylic acid, metal ions, phosphoric acid compounds and boron compounds, and biobased content were measured. Table 2 shows the results.

Pellets (A1) to (A9) and pellets (B1) to (B4) were measured for sulfur compounds according to the method described below. Table 2 shows the results (sulfur atom-equivalent content and type of sulfur compounds).
<Measurement of sulfur compound content>
Sulfur compounds were quantified using a trace nitrogen sulfur analyzer (TS-2100H model) manufactured by Mitsubishi Analyticc under the following measurement conditions.
Heater temperature: Inlet 900°C, Outlet 900°C
Gas flow rate: Ar, O ₂ each 300 ml/min
[Analysis system NSX-2100]
Measurement mode: TS
Parameter: SD-210
Measurement time (timer): 540 seconds (9 minutes)
PMT sensitivity: high concentration Identification of sulfur compounds was performed using gas chromatography (GC) and gas chromatography mass spectrometry (GC/MS). As a GC detector, an FPD (Flame Photometric Detector), which shows high sensitivity to trace amounts of sulfur compounds and phosphorus compounds, is used, and the mass components observed at the retention time when sulfur compounds are detected are analyzed. By doing so, identification was carried out.

[Example]
<Example 1>
After dry blending EVOH (A1) pellets and EVOH (B1) pellets at a mass ratio (A1/B1) of 10/90, a 30 mmφ twin screw extruder ("TEX-30SS-30CRW-2V" manufactured by Japan Steel Works, Ltd.) Using a strand die under the following conditions, the strand-shaped molten resin extruded from the strand die is cooled in a water tank, then cut with a pelletizer to form a cylindrical shape with an average diameter of 2.8 mm. A resin composition pellet of Example 1 having a length of 3.2 mm was obtained.
(Twin screw extruder conditions)
Extrusion temperature: 220°C
Screw rotation speed: 300 rpm
Extruded resin amount: 25 kg/hour Strand die: 3 mmφ, 6 holes

For the obtained resin composition pellets of Example 1, according to the methods described in the above evaluation methods (1) to (5), ethylene unit content and degree of saponification, quantification of carboxylic acid, metal ions, phosphoric acid compound and Quantitative determination of boron compounds, biobased content, and long-run properties were measured or evaluated. Table 3 shows the results.

Using a planter (upper width 28.5 cm x upper height 46.5 cm x depth 26 cm, capacity 28 L) with a drainage port 1 cm from the bottom, a water-absorbent sheet "Germ Guard" cut larger than the shelf mounting surface ( (manufactured by Toyobo Specialties Trading Co., Ltd.) was placed on the shelf, and the remainder was folded back to the bottom and placed in the planter. Furthermore, after laying a root permeable sheet (manufactured by Toyobo Specialties Trading Co., Ltd.) on the inside of the planter, the resin composition pellets of Example 1 were filled to a depth of 20 cm to obtain a plant cultivation medium. The obtained medium for plant cultivation was evaluated according to the evaluation method (6) described above. Table 3 shows the results.

<Examples 2 to 20, Comparative Examples 1 to 5>
Resin composition pellets of Examples 2 to 20 and Comparative Examples 1 to 5 were prepared in the same manner as in Example 1, except that the type and mass ratio (proportion) of EVOH used were changed as shown in Table 3. made and evaluated. Table 3 shows the results.

As shown in Table 3, the plant cultivation medium using each resin composition of Examples 1 to 20 partially uses biomass-derived raw materials, but is only derived from fossil fuels (Comparative Example 2). It had a plant growth performance comparable to that of In addition, each of the resin compositions of Examples 1 to 20 had a long-run evaluation of A or B (amount of adhesion to the die, frequency of fiber breakage) when resin composition pellets were continuously produced, and had sufficient long-run properties. It had.

In addition, from the results of Examples and Comparative Examples, in the resin composition pellets using EVOH, the growth of plants does not depend on the biobased degree, whereas the long-run property tends to increase as the biobased degree becomes lower. It was confirmed that there is a peculiar property. For example, the resin composition pellets of Examples 1, 2, 5 to 13, and 15 to 22 having a biobased degree of 65% or less had an evaluation of A for the fiber breakage frequency, and had high long-run properties. .

(Evaluation of traceability)
The sulfur compound content of the resin composition pellets obtained in Example 1 was measured and identified by the same method as that used to measure the EVOH (A) and EVOH (B) pellets. The content was 0.1 ppm in terms of sulfur atom, and the sulfur compound was dimethyl sulfide. Using the resin composition pellets of Example 1, traceability (traceability) was evaluated. Specifically, the resin composition pellet after culture medium evaluation was taken out and used as a sample for traceability. The biobased content of the removed resin composition pellets was measured according to the evaluation method (4) described above, and was 10%. Also, the sulfur compound content of the resin composition pellets taken out was measured and identified in the same manner as described above. The sulfur compound contained in the resin composition pellet was 0.1 ppm in terms of sulfur atom, and the sulfur compound was dimethyl sulfide.

REFERENCE SIGNS LIST 1 plant cultivation device 2 planter 3 opening 4 side wall 4a upper end of side wall 5 drainage port 6 water 7 bottom wall 8 shelf 8a mounting surface of shelf 9 water absorbing sheet 9a central portion of water absorbing sheet 9b edge of water absorbing sheet 10 root permeable sheet 10a Edge of root-proof and water-permeable sheet 11 Plant 12 Plant cultivation medium 13 Pellets (resin composition chips)

Claims (12)

A plant cultivation medium containing a molded body formed from a resin composition,
The resin composition contains one or more saponified ethylene-vinyl ester copolymers,
Part of the ethylene and vinyl ester, which are raw materials of the one or more ethylene-vinyl ester copolymer saponified products, is derived from biomass, and the remainder is derived from fossil fuel,
The resin composition contains a sulfur compound of 0.01 ppm or more and 100 ppm or less in terms of sulfur atoms ,
A medium for cultivating plants , wherein the one or more ethylene-vinyl ester copolymer saponified products have a biobased degree of 1% or more and 85% or less . The above one or more ethylene-vinyl ester copolymer saponified products are
It contains a saponified ethylene-vinyl ester copolymer (A) in which at least part of the raw materials ethylene and vinyl ester is derived from biomass, and a saponified ethylene-vinyl ester copolymer (B) derived from fossil fuel. , The medium for growing plants according to claim 1. Claim 2, wherein the saponified ethylene-vinyl ester copolymer (A) and the saponified ethylene-vinyl ester copolymer (B) have a mass ratio (A/B) of 1/99 to 99/1. The medium for growing plants according to . The above one or more ethylene-vinyl ester copolymer saponified products are
2. The medium for plant cultivation according to claim 1, comprising an ethylene-vinyl ester copolymer saponified product (A') in which part of the ethylene and vinyl ester as raw materials is derived from biomass and the remainder is derived from fossil fuel. 5. The medium for cultivating plants according to any one of claims 1 to 4 , wherein said resin composition has a biobased degree of 1% or more and 85 % or less. The plant cultivation medium according to any one of claims 1 to 5 , wherein the sulfur compound is dimethylsulfide or dimethylsulfoxide. The medium for cultivating plants according to any one of claims 1 to 6 , wherein at least part of the ethylene in the raw material is derived from biomass. The medium for cultivating plants according to any one of claims 1 to 7 , wherein at least part of the vinyl ester in the raw material is derived from biomass. The plant cultivation medium according to any one of claims 1 to 8 , wherein the molded body is a resin composition chip. The plant cultivation medium according to claim 9 , wherein the shape of the resin composition chips is columnar, flat, or flaky. A plant cultivation apparatus comprising the plant cultivation medium according to any one of claims 1 to 10 . A plant cultivation method comprising a step of cultivating using the plant cultivation medium according to any one of claims 1 to 10 .

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