Crosslinked resins and resin compositions

Abstract

To provide a cross-linked resin with excellent biodegradability and microbial adhesion properties. [Solution] A crosslinked resin which is a reaction product of a compound (A) having an active hydrogen group and being biodegradable and a compound (B) having an α,β-unsaturated carbonyl functional group and being biodegradable.

Description

Technical Field

[0001] The present disclosure relates to a crosslinked resin and a resin composition, and particularly to a crosslinked resin and a resin composition having biodegradability.

Background Art

[0002] Conventionally, various water retention materials made of inorganic substances or organic substances are known as agricultural soil water retention materials. In Patent Document 1, the applicant invented a liquid composition comprising (a) a hydrophilic photocurable resin having at least two ethylenically unsaturated bonds in one molecule, (b) a photopolymerization initiator, and (c) a water-soluble polymer polysaccharide capable of gelling upon contact with an alkali metal ion or a polyvalent metal ion. The composition is dropped into an aqueous medium containing an alkali metal ion or a polyvalent metal ion to gel the composition into granules, and then irradiated with active light to be cured. The granular soil water retention material thus obtained has a water retention capacity 1 to 50 times its own weight. This soil water retention material has a water retention capacity 1 to 50 times its own weight and can completely release water, so it can continuously supply water to plants and can discharge excess water during irrigation without leaving it in the soil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A resin composition as an agricultural soil water retention material that has biodegradability and excellent adhesiveness to microorganisms in the soil would be more useful.

[0005] One of the problems to be solved in the present disclosure is to provide a crosslinked resin and a resin composition having excellent biodegradability and microbial adhesiveness.

Means for Solving the Problems

[0006] This disclosure includes, for example, the following subjects:

[0007] Section 1. A crosslinked resin is a reaction product of a compound (A) having an active hydrogen group and being biodegradable, and a compound (B) having an α,β-unsaturated carbonyl functional group and being biodegradable. Section 2. The crosslinked resin according to claim 1, wherein the biodegradable compound (A) having an active hydrogen group comprises at least one compound selected from the group consisting of a biodegradable compound (A1) having an acetoacetoxy group and a biodegradable compound (A2) having an alkyloxymalonyloxy group. Section 3. The crosslinked resin according to claim 1 or 2, wherein the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group comprises a biodegradable compound (B1) having a (meth)acryloyl group. Section 4. A crosslinked resin according to any one of claims 1 to 3, wherein at least one of the compounds (A) having an active hydrogen group and being biodegradable, and (B) having an α,β-unsaturated carbonyl functional group and being biodegradable, is a water-dispersible compound or a compound having a solubility of 1 g or more in 100 g of water at 25°C. Section 5. A crosslinked resin according to any one of claims 1 to 4, wherein at least one of the compounds (A) having an active hydrogen group and being biodegradable, and (B) having an α,β-unsaturated carbonyl functional group and being biodegradable, comprises a compound having a polyoxyalkylene structure. Section 6. The crosslinked resin according to any one of claims 1 to 5, wherein the mass ratio of the biodegradable compound (A) having an active hydrogen group to the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group is in the range of (A) / (B) = 10 / 90 to 90 / 10. Section 7. A composition containing a biodegradable compound (A) having an active hydrogen group and a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group. Section 8. The composition according to item 7, further comprising a water-soluble polymeric polysaccharide (C) capable of gelling upon contact with alkali metal ions or polyvalent metal ions. Section 9. Furthermore, the composition according to item 7 or 8, further containing a microbial growth promoter (D). Section 10. A resin composition which is a reaction product of the composition described in any one of items 7 to 9. Section 11. A resin composition which is a reaction product of the composition described in item 8, and a resin composition containing a microbial growth promoter (D). Section 12. A resin composition according to claim 10 or 11, having at least one form selected from sheet, film, and particulate. Section 13. A resin composition according to any one of items 9 to 11, wherein the water content is 70% or more when immersed in deionized water at 23°C for 24 hours. Section 14. A method for producing a resin according to item 1, comprising the step of reacting a biodegradable compound (A) having an active hydrogen group with a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide crosslinked resins and resin compositions that exhibit excellent biodegradability and microbial adhesion. [Modes for carrying out the invention]

[0009] In this specification, the singular form includes both singular and plural forms unless otherwise explicitly stated herein or the context clearly contradicts it.

[0010] In this specification, "contains" is a concept that also includes "substantially consists only of" and "consists only of."

[0011] In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value of the numerical range at a certain step can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range at other steps. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples or the value that can be uniquely derived from the examples. Furthermore, in this specification, the numerical values connected by "~" mean a numerical range including the numerical values before and after "~" as the lower limit value and the upper limit value.

[0012] In this specification, "(meth)acrylate" means acrylate, methacrylate, or both, "(meth)acrylic acid" means acrylic acid, methacrylic acid, or both, and "(meth)acryloyl" means acryloyl, methacryloyl, or both.

[0013] Hereinafter, the embodiments included in the present disclosure will be further described. The embodiments described below show an example of a representative embodiment of the present disclosure, and the scope of the invention is not limited thereby.

[0014] 1. Crosslinked resin The crosslinked resin of the present disclosure is a reaction product of components including a compound (A) having an active hydrogen group and biodegradability and a compound (B) having an α,β-unsaturated carbonyl functional group and biodegradability.

[0015] The compound (A) having an active hydrogen group and biodegradability is not particularly limited as long as it contains one or more (preferably a plurality of) active hydrogen groups in one molecule and has biodegradability, and it may be a low molecular compound having a molecular weight of less than 400, an oligomer formed by polymerization of 2 to 7 monomers, or a high molecular compound having a molecular weight of 400 or more.

[0016] Examples of the active hydrogen group of the compound (A) having an active hydrogen group and biodegradability include at least one selected from the group consisting of an active methylene group, a primary and / or secondary amino group, a thiol group (mercapto group), and a hydroxyl group. Preferably, examples include at least one of an active methylene group and a primary and / or secondary amino group. The active methylene group refers to a methylene group (-CH2-) sandwiched between two electron-withdrawing groups. Examples of the active methylene group include an acetoacetoxy group, an alkyloxymalonyl oxy group, and a cyanoacetate group.

[0017] In terms of having biodegradability, the compound (A) having an active hydrogen group and biodegradability has a carbon-containing skeleton having biodegradability.

[0018] When the compound (A) having an active hydrogen group and biodegradability is a low-molecular compound, examples include ethyl acetoacetate, but the compound may include compounds not limited thereto.

[0019] When the compound (A) having an active hydrogen group and biodegradability is an oligomer, examples include polyethylene glycol (PEG) having an active hydrogen group, but the oligomer may include oligomers not limited thereto.

[0020] When the compound (A) having an active hydrogen group and biodegradability is a high-molecular compound, the compound (A) having an active hydrogen group and biodegradability includes at least one selected from the group consisting of polyvinyl alcohol (PVA), poly(oxyalkylene) glycol, polylactic acid (PLA), polyglycolic acid (PGA), polybutylene succinate (PBS), polyhydroxyalkanoic acid (PHA), polycaprolactone (PCL), and polyamide 4 (PA4) having an active hydrogen group, but may include biodegradable polymers not limited thereto. Examples of the poly(oxyalkylene) glycol include polyethylene glycol (PEG), polypropylene glycol (PPG), and polybutylene glycol. The compound (A) having an active hydrogen group and biodegradability can be used alone or in combination of two or more.

[0021] The molecular weight (number-average molecular weight in the case of a polymer) of the biodegradable compound (A) having an active hydrogen group is, for example, in the range of 400 to 20000, preferably in the range of 500 to 10000, and more preferably in the range of 500 to 5000, from the viewpoint of biodegradability and microbial adhesion.

[0022] Compound (A), which has an active hydrogen group and is biodegradable, can be produced by known methods or may be a commercially available product.

[0023] The biodegradable compound (B) having an α,β-unsaturated carbonyl functional group is not particularly limited as long as it contains one or more (preferably more) acceptor components (α,β-unsaturated carbonyl groups) per molecule and is biodegradable. Examples of the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group include at least one selected from the group consisting of (meth)acryloyloxy group-containing compounds, (meth)acrylamide group-containing compounds, maleic acid-based compounds, fumaric acid-based compounds, and itaconic acid-based compounds.

[0024] Compound (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, may be a low molecular weight compound with a molecular weight of less than 400 in which multiple identical monomers are not polymerized, or an oligomer formed by the polymerization of 2 to 7 monomers, or a high molecular weight compound with a molecular weight of 400 or more having constituent units of the same monomer formed by the polymerization of multiple identical monomers.

[0025] When compound (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, is a low-molecular-weight compound containing a (meth)acryloyloxy group, examples of compounds containing a (meth)acryloyloxy group include: ethylene glycol diacrylate, propylene glycol diacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, tetrapropylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, resolcinol diglycidyl ether diacrylate, 1,3-propanediol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, cyclohexanedimethanol diacrylate, ethoxylated neopentyl glycol diacrylate, propoxylated neopentyl glycol Examples include diacrylates such as diacrylate, ethoxylated cyclohexanedimethanol diacrylate, propoxylated cyclohexanedimethanol diacrylate, and polyester diacrylate; triacrylates such as trimethylolpropane triacrylate, glycerol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol triacrylate, and polyester triacrylate; and tetraacrylates such as di-trimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, ethoxylated dipentaerythritol tetraacrylate, and propoxylated dipentaerythritol tetraacrylate. These can be used individually or in combination of two or more.

[0026] When the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group is a polymer compound, examples of the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group include polymer compounds obtained by (1) reacting the carboxyl group of the biodegradable polymer with glycidyl (meth)acrylate, (2) reacting the hydroxyl group of the biodegradable polymer with isocyanate ethyl (meth)acrylate, or (3) transesterifying the hydroxyl group of the biodegradable polymer with methyl methacrylate, etc. Compound (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, can be used alone or in combination of two or more compounds.

[0027] The molecular weight (number-average molecular weight in the case of a polymer) of the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group is, for example, in the range of 400 to 50,000, preferably in the range of 500 to 20,000, and more preferably in the range of 500 to 10,000, from the viewpoint of biodegradability and microbial adhesion.

[0028] Compound (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, can be produced by known methods or may be a commercially available product.

[0029] In this specification, the molecular weight of a compound can be determined from its molecular formula if the formula is identifiable. If the molecular formula cannot be identified, the number-average molecular weight (polystyrene equivalent) measured by gel permeation chromatography (GPC) is used.

[0030] A crosslinked resin can be obtained by reacting a biodegradable compound (A) having an active hydrogen group with a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group.

[0031] The crosslinked resin of this disclosure, which is a crosslinked product of a compound (A) having an active hydrogen group and being biodegradable, and a compound (B) having an α,β-unsaturated carbonyl functional group and being biodegradable, exhibits excellent biodegradability and microbial adhesion.

[0032] In some preferred embodiments, the active hydrogen group-containing biodegradable compound (A) comprises at least one compound selected from the group consisting of an acetoacetoxy group-containing biodegradable compound (A1) and an alkyloxymalonyloxy group-containing biodegradable compound (A2). Resins produced using such specific compounds (A1) and / or (A2) as components exhibit excellent biodegradability, and resin compositions produced using such resins exhibit excellent biodegradability and microbial adhesion.

[0033] In some preferred embodiments, the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group includes a biodegradable compound (B1) having a (meth)acryloyl group. Resins produced using such specific compound (B1) as a component exhibit excellent biodegradability, and therefore resin compositions produced using such resins also exhibit excellent biodegradability.

[0034] In some preferred embodiments, at least one of the compounds (A), which has an active hydrogen group and is biodegradable, and (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, contains a water-dispersible compound or a compound whose solubility in 100 g of water at 25°C is 1 g or more. With this configuration, hydrophilicity is imparted to at least one of the compounds (A), which has an active hydrogen group and is biodegradable, and (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, resulting in excellent biodegradability and microbial adhesion. Examples of biodegradable compounds (A) that have an active hydrogen group and are water-dispersible or have a solubility of 1 g or more in 100 g of water at 25°C include, for example, polyvinyl alcohol (PVA) and poly(oxyalkylene) glycol, which have an active hydrogen group. Examples of biodegradable compounds (B) that have an α,β-unsaturated carbonyl functional group and are water-dispersible or have a solubility of 1 g or more in 100 g of water at 25°C include, when compound (B) is a low-molecular-weight compound containing a (meth)acryloyloxy group, examples of ethylene glycol diacrylate, propylene glycol diacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, tetrapropylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, 1,3-propanediol diacrylate, polyester diacrylate, and polyester triacrylate. When compound (B), which has α,β-unsaturated carbonyl functional groups and is biodegradable, is a polymer compound, examples include poly(oxyalkylene) glycols having α,β-unsaturated carbonyl functional groups.

[0035] In some preferred embodiments, at least one of the compounds (A), which has an active hydrogen group and is biodegradable, and (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, includes a compound having a polyoxyalkylene structure. This configuration provides excellent microbial adhesion.

[0036] In some preferred embodiments, the mass ratio of a biodegradable compound (A) having an active hydrogen group to a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group is in the range of (A) / (B) = 10 / 90 to 90 / 10. With this configuration, the strength of the crosslinked resin is maintained.

[0037] The crosslinked resins of the present disclosure described above can be used for the manufacture of resin compositions used as soil water retention materials, materials that promote the colonization of microorganisms in the soil, or by being sprayed or mixed into the soil, and in particular for the manufacture of sheets, films, or particles of hydrophilic resins for agricultural use.

[0038] 2. Compositions and resin compositions The compositions of this disclosure contain a biodegradable compound (A) having an active hydrogen group and a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group.

[0039] The details of each of the biodegradable compound (A) having an active hydrogen group and the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group are as described in section 1. Crosslinked Resins above.

[0040] The above composition may further contain a water-soluble polymeric polysaccharide (C) that has the ability to gel upon contact with alkali metal ions or polyvalent metal ions.

[0041] A water-soluble polymeric polysaccharide (C) capable of gelling upon contact with alkali metal ions or polyvalent metal ions is a polymeric polysaccharide that is water-soluble and capable of transforming into a water-insoluble or sparingly soluble gel when in contact with alkali metal ions or polyvalent metal ions in an aqueous medium. Generally, polymeric polysaccharides having a number-average molecular weight of approximately 3,000 to approximately 2,000,000, and exhibiting a solubility of at least approximately 10 g / L (25°C) in their water-soluble state before contact with alkali metal ions or polyvalent metal ions are preferred.

[0042] Specific examples of water-soluble polymeric polysaccharides (C) that have the ability to gel upon contact with alkali metal ions or polyvalent metal ions include alkali metal salts of alginic acid, pectin, and carrageenan.

[0043] Water-soluble polymeric polysaccharides (C) capable of gelling upon contact with alkali metal ions or polyvalent metal ions, when dissolved in an aqueous medium, can gel upon contact with at least one polyvalent metal ion from among alkaline earth metal ions such as magnesium ions, calcium ions, strontium ions, and barium ions; or other polyvalent metal ions such as aluminum ions, cerium ions, and nickel ions; in the case of alkali metal salts of alginic acid, gelling can occur upon contact with alkali metal ions such as potassium ions or sodium ions. The concentration of alkali metal ions or polyvalent metal ions at which gelling occurs varies depending on the type of water-soluble polymeric polysaccharide, but is generally in the range of 0.01 to 5 mol / L. These water-soluble polymeric polysaccharides (C) can be used individually or in combination of two or more types.

[0044] The above composition may further contain a microbial growth promoter (D). The microbial growth promoter (D) is a component that promotes the growth of microorganisms.

[0045] Examples of microbial growth promoters (D) include water-insoluble microbial growth promoters (D1) which are generally in the form of a solid such as a powder or lump and are poorly soluble in water, and water-soluble microbial growth promoters (D2) which are easily soluble in water. Water-insoluble microbial growth promoters (D1) are preferred.

[0046] A water-soluble microbial growth promoter (D1) that is "difficult to dissolve in water" refers to one in which 30g or more of 20°C water is required to dissolve 1g of solute.

[0047] As the water-soluble microbial growth promoter (D1), any conventionally known nutrient for microorganisms can be used without particular restriction. However, in terms of effectiveness in promoting microbial growth, it is preferable that it be at least one selected from the group consisting of polysaccharides and their derivatives. Specifically, examples include sugars such as amylose, amylopectin, starch, cellulose, hemicellulose, and chitin, and their derivatives. Each of these water-soluble microbial growth promoters (D1) can be used individually or in combination of two or more.

[0048] As a water-soluble microbial growth promoter (D1), foods containing sugars such as grains and vegetables, or processed products thereof, can be used. Specific examples include grains such as wheat, barley, rice, foxtail millet, proso millet, and corn; legumes such as soybeans, adzuki beans, and peanuts; vegetables such as potatoes and sweet potatoes; and processed products such as rice bran, wheat bran, okara (soy pulp), potato starch, cornstarch, and agar.

[0049] A "water-soluble" water-soluble microbial growth promoter (D2) refers to a substance that requires less than 30g of 20°C water to dissolve 1g of solute.

[0050] Examples of water-soluble microbial growth promoters (D2) include sugars such as glucose, fructose, maltose, sucrose, kestose, gum arabic, and guar gum. Water-soluble microbial growth promoters (D2) may be used in liquid or solid form, or dissolved in an aqueous solution. Water-soluble high molecular weight polysaccharides (C) are also included as aqueous sugars, but the material used as the microbial growth promoter (D) does not need to have gelling ability.

[0051] The water-soluble microbial growth promoter (D1) and the water-soluble microbial growth promoter (D2) may be uniformly dispersed or unevenly distributed within the hydrophilic resin particles for agricultural use.

[0052] The above composition may further contain water (G). The water may be, but is not limited to, deionized water, distilled water, or purified water.

[0053] The amounts of each component (A)-(D) and (G) in the composition and the resin composition which is a reaction product of the composition are not strictly limited and can be varied over a wide range depending on the type of each component.

[0054] In terms of the biodegradability and microbial adhesion properties of the resin composition, it is preferable that, based on a total amount of 100 parts by mass of a biodegradable compound (A) having an active hydrogen group and a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group, the components of a water-soluble polymer polysaccharide (C) capable of gelling upon contact with alkali metal ions or polyvalent metal ions and a microbial growth promoter (D) are within the following solid content ranges.

[0055] (C) Water-soluble polymeric polysaccharides capable of gelling upon contact with alkali metal ions or polyvalent metal ions: preferably 0 to 5 parts by mass, more preferably 0.03 to 2 parts by mass, (D) Water-soluble microbial growth promoter: preferably 0 to 100 parts by mass, more preferably 0.1 to 100 parts by mass, more preferably 1 to 50 parts by mass.

[0056] (G) Water: Preferably 10 to 1000 parts by mass, more preferably 50 to 500 parts by mass.

[0057] The compositions of this disclosure may contain one or more further additives. Examples of such additives include (E) nonionic surfactants.

[0058] (E) Examples of nonionic surfactants include surfactants such as polyoxyethylene alkyl ethers, polyoxyalkylene alkenyl ethers, sorbitan fatty acid esters, and glycerin fatty acid esters.

[0059] In this disclosure, a resin composition which is a reaction product of the composition described in any one of the above paragraphs is also provided.

[0060] A mixture containing a biodegradable compound (A) having an active hydrogen group, a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group, and a water-soluble polymeric polysaccharide (C) capable of gelling upon contact with alkali metal ions or polyvalent metal ions can be subjected to a crosslinking reaction.

[0061] Compound (A), which has an active hydrogen group and is biodegradable, and compound (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, are polymerized and crosslinked by a Michael addition reaction.

[0062] When the resin composition obtained by crosslinking the composition is made into particles, it is preferable that the composition contains calcium chloride. A water-soluble polymeric polysaccharide (C) that has the ability to gel upon contact with alkali metal ions or polyvalent metal ions ionically crosslinks with calcium ions, thereby promoting the crosslinking of the resin composition.

[0063] The microbial growth promoter (D) may be contained in a mixture containing components (A), (B), and (C), or it may be mixed with a crosslinked resin composition. If the microbial growth promoter (D) is a powder, it is preferable to contain it in a mixture containing components (A), (B), and (C). If the microbial growth promoter (D) is a liquid, it may be contained in a mixture containing components (A), (B), and (C), or it may be impregnated into a resin composition obtained by crosslinking the mixture.

[0064] Any of the above resin compositions may take any form, including, but are not limited to, at least one form selected from sheets, films, and particulates.

[0065] When the resin composition is in the form of particles, the average particle diameter is preferably in the range of 0.1 to 10 mm, and more preferably 2.0 to 6.0 mm, from the viewpoint of maintaining shape against water absorption and release. The average particle diameter can be calculated by measuring the diameter of hydrophilic resin particles with a ruler and taking the arithmetic mean of the diameters of a certain number (10 or more) of particles made from the resin composition.

[0066] In some preferred embodiments, the resin composition has a water content of 70% or more when immersed in deionized water at 23°C for 24 hours. Such a resin composition has excellent water retention properties.

[0067] In this specification, the moisture content is calculated using the following formula: [(Mass of resin composition after immersion) - (Mass of resin composition before immersion)] / (Mass of resin composition before immersion) * 100 (%) Because the resin composition of the present disclosure described above has excellent biodegradability and microbial adhesion properties, it can be used as a resin composition mixed into soil as a soil water retention material or as a material that promotes the settlement of microorganisms in the soil, and can be used particularly as a sheet, film, or particle of hydrophilic resin for agricultural use.

[0068] 3. Method for producing crosslinked resins and resin compositions The crosslinked resins and resin compositions of this disclosure can be obtained by various methods.

[0069] The method for producing a crosslinked resin includes a step of reacting a biodegradable compound (A) having an active hydrogen group with a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group.

[0070] The active hydrogen group of compound (A), which has an active hydrogen group and is biodegradable, acts as a donor component in the Michael addition reaction, and the α,β-unsaturated carbonyl functional group of compound (B), which has an α,β-unsaturated carbonyl functional group and is biodegradable, acts as an acceptor component in the Michael addition reaction. Therefore, a crosslinked resin is obtained by reacting component (A) and component (B). The crosslinked resin may contain a water-soluble polymeric polysaccharide (C) capable of gelling upon contact with an optionally selected alkali metal ion or polyvalent metal ion, an optionally selected microbial growth promoter (D), and / or optionally selected other additives.

[0071] The resin composition is obtained by curing a composition containing a crosslinked resin which is a reaction product of a compound (A) having active hydrogen groups and being biodegradable and a compound (B) having α,β-unsaturated carbonyl functional groups, a water-soluble polymeric polysaccharide (C) capable of gelling upon contact with an optional alkali metal ion or polyvalent metal ion, an optional microbial growth promoter (D), and an optional other additive.

[0072] In some preferred embodiments, the resin composition is a sheet-like or film-like resin composition, and the method for producing the resin composition includes polymerizing a composition containing a biodegradable compound (A) having active hydrogen groups, a biodegradable compound (B) having α,β-unsaturated carbonyl functional groups, a water-soluble polymeric polysaccharide (C) capable of gelling upon contact with an optional alkali metal ion or polyvalent metal ion, and an optional microbial growth promoter (D) to obtain a sheet-like or film-like resin composition.

[0073] In some preferred embodiments, the method for producing the resin composition includes polymerizing a composition containing a biodegradable compound (A) having an active hydrogen group, a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group, and a water-soluble polymeric polysaccharide (C) capable of gelling upon contact with an optional alkali metal ion or polyvalent metal ion to obtain a resin composition. An optional microbial growth promoter (D) may be included in the composition together with components (A) to (C), or may be attached to or included in the obtained resin composition.

[0074] In this specification, "film" refers to a thin film with a thickness of less than 250 μm. "Sheet" refers to a plate-like member with a thickness of 250 μm or more.

[0075] In some preferred embodiments, the resin composition is a particulate resin composition, and the method for producing the resin composition includes the steps of dropping a liquid composition containing a biodegradable compound (A) having an active hydrogen group, a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group, a water-soluble polymer polysaccharide (C) capable of gelling upon contact with alkali metal ions or polyvalent metal ions, and an optional microbial growth promoter (D) into an aqueous medium containing polyvalent metal ions to gel the liquid composition into granules, and polymerizing the obtained granular gel to cure the crosslinked resin in the granular gel.

[0076] The alkali metal ions or polyvalent metal ions in the aqueous medium may be at least one of the following: alkaline earth metal ions such as magnesium ions, calcium ions, strontium ions, and barium ions; or other polyvalent metal ions such as aluminum ions, cerium ions, and nickel ions.

[0077] All patent applications and document disclosures cited herein are incorporated herein by reference in their entirety.

[0078] The following examples are for illustrative purposes only and are not intended to limit the technical scope of the present invention in any way. Unless otherwise specified, reagents are obtained or prepared from commercially available sources or according to methods commonly used in the art or procedures described in prior art. [Examples]

[0079] Production of a biodegradable compound (A) having an active hydrogen group. Manufacturing Example 1 A four-necked flask equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and separator was purged with nitrogen. 2,000 parts of polyethylene glycol with a number average molecular weight of approximately 4,000, 200 parts of ethyl acetoacetate, and 0.6 parts of dioctyl tin dineodecanoate were charged into the flask. The mixture was heated to 120°C, and the reaction was carried out while distilling off the resulting ethanol. Subsequently, the unreacted ethyl acetoacetate was removed under reduced pressure to obtain a biodegradable compound (A1-1) with 100% solid content and containing acetoacetoxy groups.

[0080] Manufacturing Example 2 A four-necked flask equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and separator was purged with nitrogen. 2,000 parts of polypropylene glycol with a number average molecular weight of approximately 3,000, 240 parts of ethyl acetoacetate, and 0.6 parts of dioctyl tin dineodecanoate were charged into the flask. After heating to 120°C, the reaction was carried out while distilling off the resulting ethanol. Subsequently, the unreacted ethyl acetoacetate was removed under reduced pressure to obtain a biodegradable compound (A1-2) with 100% solid content and containing acetoacetoxy groups.

[0081] Manufacturing Example 3 A four-necked flask equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and separator was purged with nitrogen. 2,000 parts of polyethylene glycol with a number average molecular weight of approximately 400, 1,430 parts of ethyl acetoacetate, and 1 part of dioctyl tin dineodecanoate were charged into the flask. The mixture was heated to 120°C, and the reaction was carried out while distilling off the resulting ethanol. Subsequently, the unreacted ethyl acetoacetate was removed under reduced pressure to obtain a biodegradable compound (A1-3) with 100% solid content and containing acetoacetoxy groups.

[0082] Manufacturing Example 4 A four-necked flask equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and separator was purged with nitrogen. 2,000 parts of polyethylene glycol with a number average molecular weight of approximately 4,000, 200 parts of diethyl malonate, and 0.6 parts of dioctyl tin dineodecanoate were charged into the flask. After raising the temperature to 120°C, the reaction was carried out while distilling off the resulting ethanol to obtain a biodegradable compound (A1-4) with 100% solid content and containing alkyloxymalonyloxy groups.

[0083] Manufacturing Example 5 A four-necked flask equipped with a thermometer, thermostat, stirrer, reflux condenser, and nitrogen inlet tube was purged with nitrogen, and 900 parts by weight of deionized water and 100 parts of ethyl alcohol were charged and the temperature was raised to 75°C. 20 parts of a 5% aqueous solution of "V-50" (trade name, manufactured by Wako Pure Chemical Industries, Ltd., 2,2'-azobis(2-methylpropionamidine) dihydrochloride) were added, followed by the dropwise addition of 300 parts of 2-hydroxyethyl acrylate and 200 parts of 2-acetoacetoxyethyl acrylate over 3 hours. After 3 hours, 5 parts of a 5% aqueous solution of "V-50" (trade name, manufactured by Wako Pure Chemical Industries, Ltd., 2,2'-azobis(2-methylpropionamidine) dihydrochloride) were added dropwise over 10 minutes, and the mixture was stirred for a further 1 hour to obtain an acetoacetoxyethyl methacrylate copolymer acrylic resin with a solid content of 33%.

[0084] Production of a biodegradable compound (B) having α,β-unsaturated carbonyl functional groups Manufacturing Example 6 A four-necked flask equipped with a thermometer, thermostat, stirrer, reflux condenser, and air inlet was charged with 2,000 parts polyethylene glycol with a number-average molecular weight of approximately 400, 1,000 parts maleic anhydride, 1.5 parts 2,6-di-tert-butyl-4methylphenol, and 1.5 parts hydroquinone. The mixture was then heated to 100°C while blowing air into the liquid, and the reaction was allowed to proceed for 6 hours to obtain a biodegradable compound (B2-1) with 100% solid maleic acid groups.

[0085] Manufacturing example 7 A four-necked flask equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, air inlet tube, and dropping device was purged with nitrogen. 1,600 parts of polyethylene glycol with a number average molecular weight of approximately 4,000, 400 parts of polypropylene glycol with a number average molecular weight of approximately 3,000, and 222 parts of isophorone diisocyanate were charged into the flask. After raising the temperature to 80°C, 0.3 parts of dibutyltin laurate were added, and the mixture was reacted for 2 hours. While blowing air into the reaction mixture, a solution of 1 part hydroquinone dissolved in 116 parts 2-hydroxyethyl acrylate was added dropwise over 10 minutes, and the mixture was reacted at 80°C for 3 hours. After cooling to 40°C, 5,458 parts of deionized water were added to obtain an unsaturated group-containing resin with a solid content of 30%, having polymerizable unsaturated bonds at both ends of each molecule.

[0086] Production of resin particles in Examples 1-22 and Comparative Examples 1-7 Example 1 60 parts (60 parts solids) of the biodegradable compound (A1-1) having an acetoacetoxy group obtained in Production Example 1, 15 parts (15 parts solids) of the biodegradable compound (A1-2) having an acetoacetoxy group obtained in Production Example 2, 25 parts (25 parts solids) of "Light Acrylate 9EG-A" (trade name, manufactured by Kyoeisha Chemical Co., Ltd., polyethylene glycol having acryloyl groups at both ends), 3.3 parts (0.1 parts solids) of a 3% sodium alginate aqueous solution, 5 parts (5 parts solids) of "KC Floc® W-300Y" (trade name, manufactured by Nippon Paper Industries Ltd., average particle size approximately 28 μm, powdered cellulose), and 400 parts of deionized water were added to obtain a liquid composition with a solid content of 21%. The obtained liquid composition was dropped from the tip of a specific injection needle from a height of approximately 10 cm into a mixed solution of 1% aqueous calcium chloride solution and 0.1% aqueous calcium hydroxide solution to form granules, and then allowed to stand for 1 hour to obtain granular cross-linked resin particles with an average particle diameter of 3 mm.

[0087] Examples 2-11, 14-22 and Comparative Examples 1, 3, 5 Crosslinked resin particles for Examples 2-11, 14-22, and Comparative Examples 1, 3, and 5 were obtained in the same manner as in Example 1, except that the formulation composition in Example 1 was as shown in Table 1 below.

[0088] Example 12 60 parts (60 parts solids) of the biodegradable compound (A1-1) having an acetoacetoxy group obtained in Production Example 1, 15 parts (15 parts solids) of the biodegradable compound (A1-2) having an acetoacetoxy group obtained in Production Example 2, 25 parts (25 parts solids) of "Light Acrylate 9EG-A" (trade name, manufactured by Kyoeisha Chemical Co., Ltd., polyethylene glycol with acryloyl groups at both ends), 5 parts (5 parts solids) of "KC Floc® W-300Y" (trade name, manufactured by Nippon Paper Industries Ltd., average particle size approximately 28 μm, powdered cellulose), and 400 parts of deionized water were added to obtain a liquid composition with a solid content of 21%. 300 ppm of 1 mol / L sodium hydroxide aqueous solution was added to the obtained liquid composition and stirred for 5 minutes. After pouring it into a plastic case and letting it stand at room temperature for 1 hour, a sheet-like cross-linked resin sheet with a thickness of 2 mm was obtained.

[0089] Example 13 60 parts (60 parts solids) of the biodegradable compound (A1-1) having an acetoacetoxy group obtained in Production Example 1, 15 parts (15 parts solids) of the biodegradable compound (A1-2) having an acetoacetoxy group obtained in Production Example 2, 25 parts (25 parts solids) of "Light Acrylate 9EG-A" (trade name, manufactured by Kyoeisha Chemical Co., Ltd., polyethylene glycol with acryloyl groups at both ends), 5 parts (5 parts solids) of "KC Floc® W-300Y" (trade name, manufactured by Nippon Paper Industries Ltd., average particle size approximately 28 μm, powdered cellulose), and 400 parts of deionized water were added to obtain a liquid composition with a solid content of 21%. 300 ppm of 1 mol / L sodium hydroxide aqueous solution was added to the obtained liquid composition and stirred for 5 minutes. After coating with a 200 μm applicator, it was left to stand at room temperature for 1 hour to obtain a film-like crosslinked resin film with a thickness of 150 μm.

[0090] Comparative Example 2 500 parts (100 parts solids) of a 20% aqueous solution of "Gosenol Z-200" (trade name, manufactured by Mitsubishi Chemical Corporation, polyvinyl alcohol having an acetoacetyl group), 3.3 parts (0.1 parts solids) of a 3% sodium alginate aqueous solution, and 5 parts (5 parts solids) of "KC Floc® W-300Y" (trade name, manufactured by Nippon Paper Industries Ltd., average particle size approximately 28 μm, powdered cellulose) were added to obtain a liquid composition with a solid content of 21%. The obtained liquid composition was dropped from the tip of a specific injection needle from a liquid surface height of approximately 10 cm into a mixed solution of a 1% aqueous calcium chloride solution and a 0.1% aqueous calcium hydroxide solution to granulate it, and then irradiated with ultraviolet light using a high-pressure mercury lamp for 20 seconds to obtain granular cross-linked resin particles with an average particle size of 3 mm.

[0091] Comparative Example 4 100 parts (100 parts solids) of "Light Acrylate 9EG-A" (trade name, manufactured by Kyoeisha Chemical Co., Ltd., polyethylene glycol with acryloyl groups at both ends), 3.3 parts (0.1 parts solids) of 3% sodium alginate aqueous solution, 5 parts (5 parts solids) of "KC Floc® W-300Y" (trade name, manufactured by Nippon Paper Industries Ltd., average particle size approximately 28 μm, powdered cellulose), and 400 parts of deionized water were added to obtain a liquid composition with a solid content of 21%. Furthermore, 1 part of "Darocure 1173" (trade name, manufactured by Ciba Specialty Chemicals, photopolymerization initiator) was mixed in, and the obtained liquid composition was dropped into a 1% calcium chloride aqueous solution from the tip of a specific injection needle from a liquid surface height of approximately 10 cm to granulate it. Then, ultraviolet light was irradiated with a high-pressure mercury lamp for 20 seconds to obtain granular cross-linked resin particles with an average particle size of 3 mm.

[0092] Comparative Example 6 100 parts of Supersorb C (trade name, manufactured by Aquatrolls, acrylamide acrylate resin, dry powder) were added to 2,900 parts of deionized water and left to stand at room temperature for 4 hours to obtain acrylamide acrylate water-retaining gel.

[0093] The reagents used in the examples and comparative examples are as follows:

[0094] (Note 1) PEG2000 Diamine 2000 Polyethylene glycol diamine Average molecular weight approximately 2,000 Tokyo Chemical Industry Co., Ltd. (Note 2) Bremmer PP-800 Polypropylene Monomethacrylate NOF Corporation (Note 3) Light Acrylate 14EG-A PEG600 Diacrylate, Kyoeisha Chemical Co., Ltd.

[0095] Evaluation method 1. Biodegradable The biodegradability test was conducted according to the method specified in JIS K 6950, "Plastics - Determination of Aerobic Ultimate Biodegradability in Aqueous Culture Solution - Measurement of Oxygen Consumption using a Closed Respirator," and the biodegradability was evaluated according to the following criteria. A, B, and C are considered acceptable. The evaluation results are shown in Table 1.

[0096] A. Biodegradation rate after 28 days: 80% or more. B. Biodegradation rate after 28 days: 70% or more, less than 80%. C Biodegradation rate after 28 days: 60% or more, less than 70%. D. Biodegradation rate after 28 days: 20% or more, less than 60%. E. Biodegradation rate after 28 days: less than 20%.

[0097] 2. Microbial adhesion In the presence of a cross-linked resin, target microorganisms were cultured at a temperature suitable for their growth for a predetermined period to obtain microbially colonized particles. A microbial suspension was prepared by shaking 1 g of the cultured cross-linked resin composition in sterile distilled water. The number of viable bacteria in the suspension was counted by smearing, and the microbial adhesion was evaluated according to the following criteria. A, B, and C are considered acceptable. The evaluation results are shown in Table 1.

[0098] A 1 × 10⁶ CFU / g or more B: Greater than or equal to 1 × 10⁴ CFU / g, and less than 1 × 10⁶ CFU / g C is greater than or equal to 1 × 10² CFU / g and less than 1 × 10⁴ CFU / g. D: Greater than or equal to 1 × 10¹ CFU / g, and less than 1 × 10² CFU / g Less than 1×10¹ CFU / g

[0099] 3. Reswelling property After measuring the weight of the crosslinked resin swollen with water, it was placed in a hot air dryer at 80°C and dried for 1 hour. The weight of the dried crosslinked resin was recorded, and then it was immersed in deionized water at room temperature for 24 hours or more. After 24 hours or more had passed, the crosslinked resin that had reswollen with water was taken out and its weight was measured. Based on the measured weight, the water content before and after reswelling was calculated using the following formula, and the reswelling property was evaluated according to the following criteria. A, B, and C are considered qualified. The evaluation results are shown in Table 1.

[0100] 〇Water content before reswelling [(Mass of the resin composition swollen with water)−(Mass of the resin composition after drying)] / (Mass of the resin composition after drying)*100 (%) 〇Water content after reswelling [(Weight of the resin composition after reswelling)−(Weight of the resin composition after drying)] / (Mass of the resin composition after drying)*100 (%) The reswelling property was evaluated using the following formula and evaluation criteria.

[0101] Water content after reswelling / Water content before reswelling*100 (%) 〇Evaluation criteria A Reswelling property 90% or more, B Reswelling property less than 90%, 80% or more, C Reswelling property less than 80%, 70% or more, D Reswelling property less than 70%, 60% or more, E Reswelling property less than 60%

Table 1

Claims

1. A crosslinked resin is a reaction product of a compound (A) having active hydrogen groups and being biodegradable, and a compound (B) having α,β-unsaturated carbonyl functional groups and being biodegradable.

2. The crosslinked resin according to claim 1, wherein the biodegradable compound (A) having an active hydrogen group comprises at least one compound selected from the group consisting of a biodegradable compound (A1) having an acetoacetoxy group and a biodegradable compound (A2) having an alkyloxymalonyloxy group.

3. The crosslinked resin according to claim 1 or 2, wherein the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group comprises a biodegradable compound (B1) having a (meth)acryloyl group.

4. The crosslinked resin according to any one of claims 1 to 3, wherein at least one of the compounds (A) having an active hydrogen group and being biodegradable and (B) having an α,β-unsaturated carbonyl functional group is a water-dispersible compound or a compound having a solubility of 1 g or more in 100 g of water at 25°C.

5. The crosslinked resin according to any one of claims 1 to 4, wherein at least one of the compounds (A) having an active hydrogen group and being biodegradable, and (B) having an α,β-unsaturated carbonyl functional group and being biodegradable, comprises a compound having a polyoxyalkylene structure.

6. The crosslinked resin according to any one of claims 1 to 5, wherein the mass ratio of the biodegradable compound (A) having an active hydrogen group to the biodegradable compound (B) having an α,β-unsaturated carbonyl functional group is in the range of (A) / (B) = 10 / 90 to 90 / 10.

7. A composition containing a biodegradable compound (A) having an active hydrogen group and a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group.

8. The composition according to claim 7, further comprising a water-soluble polymeric polysaccharide (C) capable of gelling upon contact with alkali metal ions or polyvalent metal ions.

9. Furthermore, the composition according to claim 7 or 8, further containing a microbial growth promoter (D).

10. A resin composition which is a reaction product of the composition according to any one of claims 7 to 9.

11. A resin composition comprising a resin composition which is a reaction product of the composition described in claim 8, and a microbial growth promoter (D).

12. The resin composition according to claim 10 or 11, having at least one form selected from sheet-like, film-like, and particulate.

13. The resin composition according to any one of claims 9 to 11, wherein the water content is 70% or more when immersed in deionized water at 23°C for 24 hours.

14. A method for producing a resin according to claim 1, comprising the step of reacting a biodegradable compound (A) having an active hydrogen group with a biodegradable compound (B) having an α,β-unsaturated carbonyl functional group.

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