Microorganism-immobilizing carrier for water treatment, resin foam and raw material composition thereof

Abstract

Provided are: a support for immobilizing microorganisms for water treatment, the support being hydrophilic and water swellable, and also having excellent chemical resistance and abrasion resistance; a resin-foamed body used for the support; and a starting material composition thereof. A support for immobilizing microorganisms for water treatment according to the present invention is formed of a resin-foamed body that contains a carbodiimide group, the resin-foamed body being made with a resin-foamed body starting material composition that includes a carbodiimide group-containing compound. The volume expansion ratio, which is expressed by the ratio of the water-swelled volume to the absolute dry state volume, is 110-1000%.

Description

[Technical field]

[0001] The present invention relates to a microorganism-immobilized carrier for water treatment (hereinafter, also simply referred to as the carrier), as well as a resin foam and a raw material composition for the resin foam to be used therein. [Background technology]

[0002] In the treatment of organic wastewater such as sewage, human waste, and industrial wastewater, a method of treating the water by decomposing organic matter using microorganisms is adopted. One of such treatment methods using microorganisms is an immobilization method in which microorganisms are attached to carriers such as resins and ceramics. Carriers with immobilized microorganisms (microorganism immobilization carriers) are used in the form of fixed beds that are held at a predetermined position in a water treatment tank, or fluidized beds that are used in a state where they can be moved by aeration from the viewpoint of improving the water treatment capacity of microorganisms, etc.

[0003] For example, Patent Document 1 describes the use of a hydrophilic and water-swellable flexible polyurethane foam as the carrier. These flexible polyurethane foams allow microorganisms to easily penetrate into the carrier, and are therefore suitable materials for efficient water treatment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] China Utility Model No. 204454746 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned carrier is further required to have resistance to water treatment chemicals such as an aqueous solution of hypochlorous acid, that is, chemical resistance. In particular, carriers used as fluidized beds may be used in a state where they repeatedly collide with each other or with the inner walls of a water treatment tank, etc., so wear resistance is also one of the important properties required of the carrier.

[0006] However, while a carrier that has excellent hydrophilicity and water swelling properties and quickly settles in water when added to the water can improve the efficiency of water treatment, it generally has poor chemical resistance and abrasion resistance. In addition, a carrier that has excellent abrasion resistance does not necessarily have excellent chemical resistance.

[0007] The present invention has been made in order to solve such problems, and an object of the present invention is to provide a microorganism-immobilizing carrier for water treatment that combines not only hydrophilicity and water-swelling properties but also excellent chemical resistance and abrasion resistance, as well as a resin foam and a raw material composition thereof to be used therefor. [Means for solving the problem]

[0008] The present invention is based on the finding that a resin foam produced by blending a carbodiimide group-containing compound has excellent chemical resistance and abrasion resistance.

[0009] That is, the present invention provides the following [1] to

[24] . [1] A microorganism immobilization carrier for water treatment, formed of a resin foam containing carbodiimide groups. [2] The microorganism-immobilizing carrier for water treatment according to the above [1], wherein the resin foam is a flexible polyurethane foam. [3] The microorganism-immobilizing carrier for water treatment according to the above [1] or [2], which has a volume swelling ratio, expressed as the ratio of the volume when swollen with water to the volume in an absolutely dry state, of 110 to 1000%. [4] The swelling density when swollen in water is 20.0 to 70.0 kg / m 3 The microorganism-immobilizing carrier for water treatment according to any one of the above [1] to [3], [5] The microorganism-immobilizing carrier for water treatment according to any one of the above [1] to [4], which has an average number of pores when swollen with water of 9 to 40 pores / 25 mm.

[0010] [6] A resin foam for use as a microorganism immobilization carrier for water treatment, the resin foam containing carbodiimide groups and having a volume swelling ratio, expressed as the ratio of the volume when swollen with water to the volume in an absolutely dry state, of 110 to 1,000%. [7] The resin foam according to [6] above, wherein the resin foam is a flexible polyurethane foam. [8] The swelling density when swollen in water is 20.0 to 70.0 kg / m 3 The resin foam according to the above [6] or [7], [9] The resin foam according to any one of the above [6] to [8], which has an average number of pores when swollen in water of 9 to 40 pores / 25 mm.

[10] The resin foam according to any one of the items [6] to [9] above, wherein a test piece of the resin foam is subjected to the following (Test 1), then washed with water and dried at 110°C for 2 hours, and the mass remaining rate of the test piece is more than 75%. (Test 1) A cubic test piece with a side length of 10 mm when swollen in water is immersed in an aqueous sodium hypochlorite solution with an effective chlorine concentration of 0.2% by mass at 25°C for 2 hours.

[11] The resin foam according to any one of the items [6] to

[10] above, wherein a test piece of the resin foam is subjected to the following (Test 2), then washed with water and dried at 110°C for 2 hours, and the mass remaining rate of the test piece is more than 55%. (Test 2) Twenty cubic test pieces, each 10 mm on a side, were immersed in an aqueous solution of sodium hypochlorite with an effective chlorine concentration of 0.2% by mass for two hours. These were then washed with water and dried at 110°C for two hours. They were then placed in 200 mL of pure water in a cylindrical container (inner diameter 105 mm, height 100 mm) with waterproof sandpaper (#100) attached to the inner surface. A stirring blade (three-blade turbine blade, diameter 66 mm, height 14 mm, shaft diameter 8 mm) was placed at a position 10 mm away from the center of the bottom of the container, and the pieces were stirred at a rotation speed of 400 rpm at 25°C for 24 hours.

[0011]

[12] A resin foam raw material composition which is a part of a resin foam composition for producing a resin foam for use in a microorganism-immobilizing carrier for water treatment, the resin foam raw material composition comprising a carbodiimide group-containing compound.

[13] The resin foam raw material composition according to

[12] above, wherein the resin foam is a flexible polyurethane foam produced from a resin foam composition (1) containing a polyisocyanate compound (e1), a polyol compound (f1), and a blowing agent (f2), and the resin foam raw material composition is a part of the resin foam composition (1), and contains the polyol compound (f1), the blowing agent (f2), and a carbodiimide group-containing compound.

[14] The resin foam raw material composition according to

[12] above, wherein the resin foam is a flexible polyurethane foam produced from a resin foam composition (1) containing a polyisocyanate compound (e1), a polyol compound (f1) and a blowing agent (f2), and the resin foam raw material composition is a part of the resin foam composition (1), and contains the polyisocyanate compound (e1) and a carbodiimide group-containing compound.

[15] The resin foam raw material composition according to

[12] above, wherein the resin foam is a flexible polyurethane foam produced from a resin foam composition (2) comprising a polyisocyanate compound (a1), a urethane prepolymer (a2), a curing agent (b1), and a blowing agent (b2), and the resin foam raw material composition is a part of the resin foam composition (2), and comprises the curing agent (b1), the blowing agent (b2), and a carbodiimide group-containing compound.

[16] The resin foam is a flexible polyurethane foam produced from a resin foam composition (2) containing a polyisocyanate compound (a1), a urethane prepolymer (a2), a curing agent (b1), and a blowing agent (b2), and the resin foam raw material composition according to

[12] above is a part of the resin foam composition (2), and contains the polyisocyanate compound (a1), the urethane prepolymer (a2), and a carbodiimide group-containing compound.

[17] The resin foam raw material composition according to

[12] above, wherein the resin foam is a flexible polyurethane foam produced from a resin foam composition (3) comprising a carbodiimide group-containing compound (c1), a urethane prepolymer (c2), a curing agent (d1) and a blowing agent (d2), the resin foam being a part of the resin foam composition (3), comprising the carbodiimide group-containing compound (c1) and the urethane prepolymer (c2), and the carbodiimide group-containing compound (c1) comprises a carbodiimide-modified polyisocyanate compound.

[18] The resin foam raw material composition according to any one of the above

[15] to

[17] , wherein the urethane prepolymer (a2) or (c2) is a reaction product of a polyether polyol and a polyisocyanate compound (x) and is a polyether-based urethane prepolymer having two or more isocyanate groups in one molecule.

[19] The resin foam raw material composition according to

[18] above, wherein the polyether polyol is an ethylene oxide-propylene oxide copolymer.

[20] The resin foam raw material composition according to any one of the above

[15] to

[19] , wherein the curing agent (b1) or (d1) is water.

[21] The resin foam raw material composition according to any one of the above

[13] to

[20] , wherein the blowing agent (f2), (b2) or (d2) is water.

[0012]

[22] A method for producing a resin foam using the resin foam raw material composition according to the above

[13] or

[14] , comprising reacting the resin foam composition (1) containing a carbodiimide group-containing compound to obtain a flexible polyurethane foam.

[23] A method for producing a resin foam using the resin foam raw material composition according to

[15] or

[16] above, comprising reacting the resin foam composition (2) containing a carbodiimide group-containing compound to obtain a flexible polyurethane foam.

[24] A method for producing a resin foam using the resin foam raw material composition according to

[17] above, comprising reacting the resin foam composition (3) containing a carbodiimide group-containing compound to obtain a flexible polyurethane foam. Effect of the Invention

[0013] According to the present invention, there can be provided a microorganism-immobilizing carrier for water treatment which has excellent hydrophilicity and water swelling properties as well as excellent chemical resistance and abrasion resistance. The present invention also provides a resin foam suitable for a microorganism-immobilized carrier for water treatment, and a raw material composition suitable for obtaining the resin foam. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the microorganism-immobilized carrier for water treatment, and the resin foam and raw material composition thereof used therein will be described in detail.

[0015] [Microbial immobilization carrier for water treatment] The microorganism-immobilizing carrier for water treatment of the present invention is characterized in that it is formed of a resin foam containing a carbodiimide group. As conventional microorganism immobilization carriers for water treatment made of resin foams, those made of flexible polyurethane foams are known, but those using a carbodiimide group-containing compound as a raw material for producing resin foams such as flexible polyurethane foams are not known. By using a carbodiimide group-containing compound as a manufacturing raw material, a resin foam containing the carbodiimide groups possessed by the carbodiimide group-containing compound can be formed into a carrier having excellent hydrophilicity and water-swelling property, as well as improved chemical resistance and abrasion resistance.

[0016] The resin foam is a foam or a porous body molded in a state in which air bubbles are uniformly or non-uniformly dispersed in the resin. The type of resin is not particularly limited as long as it is applicable to the immobilization of microorganisms. Examples of the resin foam include soft polyurethane foam, hard polyurethane foam, polystyrene foam, polyethylene foam, polypropylene foam, polyvinyl alcohol foam, ethylene-vinyl acetate copolymer foam, polyethylene terephthalate foam, phenolic resin foam, silicone foam, polyvinyl chloride foam, urea resin foam, acrylic resin foam, polyimide foam, ethylene propylene diene rubber foam, etc. Among these, from the viewpoint of obtaining a carrier having hydrophilicity and water swelling properties, soft polyurethane foam, hard polyurethane foam, ethylene-vinyl acetate copolymer foam, polyethylene terephthalate foam, urea resin foam, acrylic resin foam, etc. are preferred, and soft polyurethane foam is more preferred.

[0017] From the viewpoint of improving hydrophilicity, the surface of the resin foam may be coated with, for example, a glycol compound such as polypropylene glycol, ethylene glycol, glycerin, or acetylene glycol, a surfactant, or the like.

[0018] The carbodiimide group present in the resin foam has a wave number of 2100 to 2200 cm in an infrared absorption (IR) spectrum. -1 Its presence or absence can be confirmed by observing an absorption peak within the range. The reason why the microorganism immobilization carrier for water treatment of the present invention exhibits excellent chemical resistance and abrasion resistance is not clear, but a carbodiimide group-containing compound having a carbodiimide group is known to improve the hydrolysis resistance of a resin, and it is believed that the presence of such a carbodiimide group contributes to the improvement of the chemical resistance and abrasion resistance.

[0019] The shape of the carrier is not particularly limited, and may be, for example, a cube, a rectangular column, a cylindrical column, or the like, a polyhedron, a chip shape, a sphere, or the like, taking into consideration the shape and size of the water treatment tank, water swelling properties, microbial immobilization ability, etc. From the viewpoints of production efficiency, cost, etc., a cube or a rectangular parallelepiped is preferable. The size of the carrier is not particularly limited, and can be appropriately set in consideration of the shape and size of the water treatment tank, water swelling property, microbial immobilization ability, handling property, production efficiency, etc. For example, in the case of a rectangular parallelepiped carrier, the length of each side is preferably about 3 to 200 mm, more preferably 5 to 100 mm, even more preferably 7 to 50 mm, and even more preferably 8 to 30 mm.

[0020] From the viewpoints of good hydrophilicity, chemical resistance, abrasion resistance, and the like, the carrier preferably has a volume swelling rate due to swelling in water of 110 to 1000%, more preferably 115 to 800%, even more preferably 120 to 500%, and still more preferably 120 to 300%.

[0021] The term "volume swelling ratio" as used herein refers to a value expressed as the ratio of the volume of the carrier (or resin foam) when swollen with water to the volume of the carrier (or resin foam) in an absolutely dry state. The "volume in an absolute dry state" includes the pores (cells) of the carrier (or resin foam), and is the volume calculated based on the external dimensions of the carrier (or resin foam) in an absolute dry state. For example, when the carrier (or resin foam) is a rectangular parallelepiped, the volume of the carrier is calculated as the product of the lengths of the length, width, and height of the rectangular parallelepiped. The term "absolutely dry state" refers to a state in which the carrier (or resin foam) is dried at a temperature equal to or lower than the heat resistance temperature of the resin (for example, 110°C when the resin foam is a soft polyurethane foam) and no loss in mass is observed. It is also called an absolutely dry state. The "volume when swollen with water" includes the pores of the carrier (or resin foam) and the water absorbed therein, and is the volume determined based on the external dimensions of the carrier (or resin foam) in a water-swollen state. The volume can be determined in the same manner as the volume in an absolute dry state described above. "When swollen in water" refers to the state in which the carrier is immersed in pure water at 25°C for 1 hour.

[0022] From the viewpoint of efficient water treatment, the carrier has a swelling density when swollen with water of 20.0 to 70.0 kg / m 3is preferable, and more preferably 25.0 to 60.0 kg / m 3 , and more preferably 27.0 to 55.0 kg / m 3 It is. The swelling density is 20.0 kg / m 3 If the density is more than 70.0 kg / m, the strength is sufficient, the deformation is difficult, and clogging of the screen of the water treatment tank and leakage due to passing through are suppressed. From the viewpoint of the water treatment effect commensurate with the manufacturing cost, the swelling density is 70.0 kg / m 3 It is preferable that: Here, the "swelling density" referred to in the present invention refers to a value obtained by dividing the mass of the carrier (or resin foam) in an absolute dry state by the volume when swollen in water. Specifically, the swelling density can be measured by the method described in the examples below.

[0023] The carrier preferably has an oven-dry density of 35.0 to 120.0 kg / m 3 , more preferably 40.0 to 100.0 kg / m 3 , and more preferably 45.0 to 80.0 kg / m 3 It is.

[0024] The cellular (cell) structure of the carrier is preferably an interconnected pore structure from the viewpoint of allowing the microorganisms, oxygen, and substrates serving as nutrient sources for the microorganisms to penetrate sufficiently inside in water, thereby facilitating immobilization of the microorganisms on the carrier. The cell structure preferably has an average pore number of 9 to 40 pores / 25 mm when swollen with water, more preferably 10 to 35 pores / 25 mm, and even more preferably 11 to 30 pores / 25 mm. Here, the "average number of pores when swollen in water" in the present invention refers to the average number of pores present on any three straight lines of 25 mm length in the carrier (or resin foam) when swollen in water.

[0025] Furthermore, from the viewpoint of allowing sufficient penetration of microorganisms, oxygen, and substrates that serve as nutrient sources for microorganisms in water and facilitating immobilization of microorganisms on the carrier, the cell structure of the carrier preferably has an average pore size of 0.20 to 2.00 mm when swollen in water, more preferably 0.40 to 1.90 mm, and even more preferably 0.50 to 1.80 mm.

[0026] Furthermore, from the viewpoint of maintaining a sufficient pore size and surface area, the resin skeleton portion constituting the cell structure of the carrier preferably has a width of the smallest part of the skeleton between adjacent pores of 0.02 to 0.50 mm, more preferably 0.03 to 0.40 mm, and even more preferably 0.05 to 0.30 mm. Furthermore, as a cell structure suitable for immobilizing a large number of microorganisms in water, it is preferable that the skeletal portion be a so-called wall structure in which the spaces between adjacent pores are partially membrane-like and partitioned by walls with a large surface area, rather than a so-called rib structure consisting of a thin rod-like skeleton.

[0027] [Resin foam] The resin foam of the present invention is a resin foam for use as a microorganism immobilization carrier for water treatment, and is characterized in that it contains carbodiimide groups and has a volume swelling ratio, expressed as the ratio of the volume when swollen with water to the volume in an absolutely dry state, of 110 to 1000%. The resin foam of the present invention is a resin foam containing carbodiimide groups and having a predetermined volume swelling ratio, similar to the resin foam described above in the section [Microorganism-immobilized carrier for water treatment]. Such a resin foam is excellent in hydrophilicity and water swelling, and can be suitably used to form a microorganism-immobilized carrier for water treatment having improved chemical resistance and abrasion resistance.

[0028] Specific materials such as the type of resin of the resin foam are the same as those explained in the section of [Microorganism-immobilizing carrier for water treatment] above, and soft polyurethane foam is more preferable.

[0029] From the viewpoint of good hydrophilicity, chemical resistance, abrasion resistance, and the like required of a carrier, the resin foam has a volumetric swelling rate due to swelling in water of 110 to 1000%, preferably 115 to 800%, more preferably 120 to 500%, and even more preferably 120 to 300%.

[0030] The swelling density and average pore number of the resin foam when swollen in water are preferably similar to those of the carrier described above in the section [Microorganism-immobilized carrier for water treatment]. That is, the resin foam has a swelling density when swollen with water of 20.0 to 70.0 kg / m 3 is preferable, and more preferably 25.0 to 60.0 kg / m 3 , and more preferably 27.0 to 55.0 kg / m 3 It is. The resin foam preferably has an average pore number of 9 to 40 pores / 25 mm when swollen with water, more preferably 10 to 35 pores / 25 mm, and further preferably 11 to 30 pores / 25 mm.

[0031] Other physical properties of the resin foam are preferably similar to those of the carrier described above in the section [Microorganism-immobilized carrier for water treatment], and the meanings of each term are similar to those described for the carrier.

[0032] The resin foam preferably has a mass residual rate of more than 75% when a test piece is subjected to the following (Test 1), washed with water, and dried at 110° C. for 2 hours. (Test 1) A cubic test piece with a side length of 10 mm when swollen in water is immersed in an aqueous sodium hypochlorite solution with an effective chlorine concentration of 0.2% by mass at 25°C for 2 hours.

[0033] (Test 1) is a test to evaluate the degree of wear of the resin foam (carrier) when a test piece of a typical carrier shape is immersed in a water treatment chemical using a sodium hypochlorite aqueous solution, which is a typical water treatment chemical. That is, the mass remaining rate is an evaluation index of chemical resistance. (Test 1) is specifically performed by the method of the chemical resistance evaluation test in the following examples. As a resin foam in which consumption when immersed in water treatment chemicals is suppressed, i.e., in which chemical resistance is improved, the mass remaining rate after the above-mentioned test is preferably more than 75%, more preferably 77% or more, and even more preferably 80% or more.

[0034] The resin foam preferably has a mass residual rate of more than 55% when a test piece is subjected to the following (Test 2), washed with water, and dried at 110° C. for 2 hours. (Test 2) Twenty cubic test pieces, each 10 mm on a side, were immersed in an aqueous solution of sodium hypochlorite with an effective chlorine concentration of 0.2% by mass for two hours. These were then washed with water and dried at 110°C for two hours. They were then placed in 200 mL of pure water in a cylindrical container (inner diameter 105 mm, height 100 mm) with waterproof sandpaper (#100) attached to the inner surface. A stirring blade (three-blade turbine blade, diameter 66 mm, height 14 mm, shaft diameter 8 mm) was placed at a position 10 mm away from the center of the bottom of the container, and the pieces were stirred at a rotation speed of 400 rpm at 25°C for 24 hours.

[0035] (Test 2) is a test for evaluating the degree of wear of the resin foam (carrier) due to collisions between the carriers or with the inner wall of the water treatment tank, assuming that the carrier is used as a fluidized bed in the water treatment tank. In other words, the mass remaining rate is an evaluation index for wear resistance. This test can be evaluated by using a test piece that has undergone (Test 1) above and determining the mass remaining rate of the test piece in flowing pure water in a container with a rough inner surface. (Test 2) is specifically performed by the method of the wear resistance evaluation test in the following examples. For a resin foam in which wear due to use of the carrier in a water treatment tank is suppressed, i.e., in which wear resistance is improved, the mass remaining rate after the above-mentioned test is preferably more than 55%, more preferably 57% or more, and even more preferably 59% or more.

[0036] [Raw material composition for resin foam] The resin foam raw material composition of the present invention is part of a resin foam composition for producing a resin foam for use as a microorganism immobilization carrier for water treatment, and is characterized by containing a carbodiimide group-containing compound. In the present invention, the term "resin foam composition" refers to all of the raw materials for the resin foam, and is foamed and cured to obtain a resin foam. The term "resin foam raw material composition" (hereinafter sometimes abbreviated as raw material composition) refers to a part of the resin foam composition. That is, the carbodiimide group-containing compound is blended in at least a part of the raw material composition of the resin foam composition.

[0037] <Carbodiimide group-containing compound> The carbodiimide group-containing compound is a compound containing a carbodiimide group (-N=C=N-) in the molecule. The carbodiimide group-containing compound is not particularly limited, and may be a monocarbodiimide compound containing one carbodiimide group, or a polycarbodiimide compound containing two or more carbodiimide groups. Of these, one type may be used alone, or two or more types may be used in combination. From the viewpoint of chemical resistance and abrasion resistance, a polycarbodiimide compound is preferred, and from the viewpoint of storage stability of the composition, an aliphatic polycarbodiimide compound is preferred. In addition, from the viewpoint of uniform dispersion of bubbles in a resin foam, the carbodiimide group-containing compound is preferably hydrophilic.

[0038] Examples of the carbodiimide group-containing compound include aromatic monocarbodiimides such as diphenylcarbodiimide, bis(methylphenyl)carbodiimide, bis(methoxyphenyl)carbodiimide, bis(nitrophenyl)carbodiimide, bis(dimethylphenyl)carbodiimide, bis(diisopropylphenyl)carbodiimide, and bis(di-t-butylphenyl)carbodiimide; and aliphatic monocarbodiimide compounds such as dicyclohexylcarbodiimide, diisopropylcarbodiimide, and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide.

[0039] In addition, as the carbodiimide group-containing compound, a compound in which a carbodiimide group is generated by subjecting the same or different polyisocyanate compounds to a decarboxylation condensation reaction by a known method, for example, using a carbodiimide catalyst such as an organic phosphorus compound or an organic metal compound, i.e., a carbodiimide-modified polyisocyanate compound, is also preferred. Examples of the polyisocyanate compound include toluene diisocyanate (TDI), xylylene diisocyanate, diphenylmethane diisocyanate (MDI), naphthylene diisocyanate, biphenylene diisocyanate, diphenyl ether diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

[0040] In addition, when the carbodiimide group-containing compound is a carbodiimide-modified polyisocyanate compound, the terminal isocyanate group may be a polycarbodiimide compound blocked by reacting with a terminal blocking compound having one group reactive with an isocyanate group. Examples of the end-capping compound include monoisocyanates such as phenyl isocyanate, tolyl isocyanate, isopropyl phenyl isocyanate, and cyclohexyl isocyanate; alcohols such as methanol, isopropyl alcohol, phenol, and polyethylene glycol monomethyl ether; amines such as butylamine, diethylamine, and cyclohexylamine; and carboxylic acids such as propionic acid and benzoic acid.

[0041] In addition, when the carbodiimide group-containing compound is synthesized by a decarboxylation condensation reaction of a polyisocyanate compound, it may be synthesized using a chain extender such as a glycol compound such as ethylene glycol, propanediol, or butanediol.

[0042] <Resin foam composition> The resin foam is preferably a flexible polyurethane foam produced from any one of the resin foam compositions (1) to (3). In order to obtain a resin foam for use as a microorganism-immobilized carrier for water treatment having excellent hydrophilicity and water swelling properties and improved chemical resistance and abrasion resistance, it is preferable that any one of the resin foam compositions (1) to (3) contains a carbodiimide group-containing compound. Therefore, the raw material composition is preferably any one of the raw material compositions of resin foam compositions (1) to (3). Specific examples of such raw material compositions include the following five embodiments: (1-1), (1-2), (2-1), (2-2) and (3-1).

[0043] (1-1) A part of the resin foam composition (1) in the case where the resin foam is a flexible polyurethane foam produced from the resin foam composition (1) containing a polyisocyanate compound (e1), a polyol compound (f1), and a blowing agent (f2), the part comprising the resin foam composition (1), the raw material composition containing the polyol compound (f1), the blowing agent (f2), and a carbodiimide group-containing compound. (1-2) A raw material composition which is a part of the resin foam composition (1), and which contains a polyisocyanate compound (e1) and a carbodiimide group-containing compound. (2-1) In the case where the resin foam is a flexible polyurethane foam produced from a resin foam composition (2) containing a polyisocyanate compound (a1), a urethane prepolymer (a2), a curing agent (b1), and a blowing agent (b2), a part of the resin foam composition (2), the part comprising the curing agent (b1), the blowing agent (b2), and a carbodiimide group-containing compound. (2-2) A raw material composition which is a part of the resin foam composition (2), and which contains a polyisocyanate compound (a1), a urethane prepolymer (a2), and a carbodiimide group-containing compound. (3-1) A raw material composition which is a part of the resin foam composition (3) in the case where the resin foam is a flexible polyurethane foam produced from the resin foam composition (3) containing a carbodiimide group-containing compound (c1), a urethane prepolymer (c2), a curing agent (d1) and a blowing agent (d2), and which contains a carbodiimide group-containing compound (c1) and a urethane prepolymer (c2), and the carbodiimide group-containing compound (c1) contains a carbodiimide-modified polyisocyanate compound.

[0044] Among the above-mentioned embodiments, in consideration of the reactivity of the carbodiimide group-containing compound in the raw material composition, the raw material composition of the embodiment (1-1), (2-1) or (3-1) is preferred. When the carbodiimide group-containing compound is a carbodiimide-modified polyisocyanate compound, the raw material composition of the embodiment (2-2) is also preferred.

[0045] <Resin foam composition (1)> The resin foam composition (1) usually constitutes a two-liquid type flexible polyurethane foam consisting of a liquid E containing a polyisocyanate compound (e1) and a liquid F containing a polyol compound (f1) and a blowing agent (f2). In the embodiment (1-1), a carbodiimide group-containing compound is blended into the liquid F, and in the embodiment (1-2), a carbodiimide group-containing compound is blended into the liquid E. In this way, the carbodiimide group-containing compound may be contained in either of the two liquids constituting the resin foam composition (1), or may be contained in both of them.

[0046] From the viewpoint of the effect of improving the chemical resistance and abrasion resistance of the resin foam by adding the carbodiimide group-containing compound, the amount of the carbodiimide group-containing compound added is preferably 0.005 to 25.0 parts by mass, more preferably 0.01 to 15.0 parts by mass, even more preferably 0.02 to 10.0 parts by mass, and still more preferably 0.04 to 8.0 parts by mass, relative to 100 parts by mass of the combined total of Liquid E and Liquid F (excluding the carbodiimide group-containing compound).

[0047] The polyisocyanate compound (e1) is a compound having two or more isocyanate groups in one molecule, and is not particularly limited. Specific examples of the polyisocyanate compound (e1) include the same as those exemplified for the polyisocyanate compound used in the synthesis of the above-mentioned carbodiimide-modified polyisocyanate compound. The polyisocyanate compound (e1) may be used alone or in combination of two or more kinds. The polyisocyanate compound (e1) does not have a carbodiimide group and is to be differentiated from the carbodiimide-modified polyisocyanate compound. The same applies to the polyisocyanate compound (a1) and the polyisocyanate compound (x) described below.

[0048] When the polyisocyanate compound (e1) is a compound having isomers, it may be only one of each isomer or a mixture of two or more isomers. For example, TDI has two isomers, toluene-2,4-diisocyanate (2,4-TDI) and toluene-2,6-diisocyanate (2,6-TDI), and either 2,4-TDI or 2,6-TDI may be used alone, or a mixture of the two may be used. When simply referring to TDI, it refers to the mixture, and the molar ratio of 2,4-TDI to 2,6-TDI is usually 80 / 20.

[0049] MDI has three isomers, 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), and 4,4'-diphenylmethane diisocyanate (4,4'-MDI), and any one of these may be used. Usually, among these isomers, monomeric MDI (also called pure MDI) containing 4,4'-MDI as the main component, or polymeric MDI (also called crude MDI) which is a mixture of monomeric MDI and polymethylene polyphenyl polyisocyanate, which is a polynuclear compound, is used. When simply referring to MDI, it is meant to include these.

[0050] The polyisocyanate compound (e1) is preferably blended in an amount such that the resin raw material composition (1) has an isocyanate index of 70-130, more preferably 80-120, and further preferably 85-115.

[0051] Examples of the polyol compound (f1) include polyether polyol, polyester polyol, dimer acid polyol, polydiene polyol, etc. Among these, one type may be used alone, or two or more types may be used in combination. Among these, polyether polyol is preferred from the viewpoint of hydrophilicity and chemical resistance of the resin foam.

[0052] In addition, from the viewpoint of promoting the reaction between the polyisocyanate compound (e1) and the polyol compound (f1), the E liquid may contain a known catalyst used in the synthesis of flexible polyurethane foams. Examples of the catalyst include amine catalysts such as triethylamine, triethylenediamine, diethanolamine, N-methylmorpholine, N-ethylmorpholine, and tetramethylguanidine; tin catalysts such as stannous octoate and dibutyltin dilaurate; and other metal catalysts such as phenylmercury propionate and lead octenate.

[0053] The blowing agent (f2) is used to form a flexible polyurethane foam. The blowing agent (f2) generates carbon dioxide gas by reacting with isocyanate groups during the polyurethane production reaction, and the blowing agent itself generates heat and vaporizes, thereby foaming the polyurethane. Examples of the blowing agent (f2) include water, hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), hydrochlorofluoroolefins (HCFOs), carbon dioxide, and hydrocarbons such as cyclopentane. These may be used alone or in combination of two or more. Among these, water is preferably used alone from the viewpoints of ease of handling, cost, environmental conservation, and the like.

[0054] If necessary, Liquid E and / or Liquid F may contain a solvent, as well as additives known in the production of flexible polyurethane foams, such as inorganic fillers, foam stabilizers, and colorants, within limits that do not impair the effects of the present invention. By using the inorganic filler, the specific gravity of the flexible polyurethane foam to be produced can be adjusted, and a microorganism-immobilized carrier for water treatment produced using the flexible polyurethane foam can be quickly settled in water when it is placed in water. Examples of the inorganic filler include barium sulfate, calcium carbonate, talc, silica, alumina, activated carbon, and zeolite. These may be used alone or in combination of two or more. Among these, barium sulfate is preferred from the viewpoint of specific gravity and the like. The foam stabilizer adjusts the state of the foam. Examples of the foam stabilizer include surfactants and silicone oils. Among these, one type may be used alone, or two or more types may be used in combination. Among these, nonionic surfactants are preferred because they have a hydroxyl group at the molecular end, can chemically bond with isocyanate, and cause little foaming.

[0055] The resin foam can be produced from the resin foam composition (1) by reacting the resin foam composition (1) containing a carbodiimide group-containing compound, which is obtained by mixing liquid E and liquid F. A known method for producing a two-liquid type flexible polyurethane foam can be applied to obtain a flexible polyurethane foam as the resin foam. The resin foam can be used as a microorganism-immobilizing carrier for water treatment by, for example, cutting a block (slab) of the resin foam into a desired size and shape.

[0056] <Resin foam composition (2)> The resin foam composition (2) usually constitutes a two-liquid type flexible polyurethane foam consisting of a liquid A containing a polyisocyanate compound (a1) and a urethane prepolymer (a2) and a liquid B containing a curing agent (b1) and a blowing agent (b2). In the embodiment (2-1) above, a carbodiimide group-containing compound is blended in the liquid B, and in the embodiment (2-2) above, a carbodiimide group-containing compound is blended in the liquid A. In this way, the carbodiimide group-containing compound may be contained in either of the two liquids constituting the resin foam composition (2), or may be contained in both of them.

[0057] From the viewpoint of the effect of improving the chemical resistance and abrasion resistance of the resin foam by adding the carbodiimide group-containing compound, the amount of the carbodiimide group-containing compound added is preferably 0.005 to 25.0 parts by mass, more preferably 0.01 to 15.0 parts by mass, even more preferably 0.02 to 10.0 parts by mass, and still more preferably 0.04 to 8.0 parts by mass, relative to 100 parts by mass in total of Liquid A and Liquid B (excluding the carbodiimide group-containing compound).

[0058] The polyisocyanate compound (a1) is not particularly limited, and specific examples include the same as those exemplified for the polyisocyanate compound (e1) constituting the above-mentioned resin foam composition (1). The polyisocyanate compound (a1) may be used alone or in combination of two or more. Among these, TDI and / or MDI are preferably used from the viewpoint of the chemical resistance and abrasion resistance of the produced resin foam. When MDI is used as the polyisocyanate compound (a1), for example, it may be pure MDI or crude MDI, and from the viewpoints of the chemical resistance and abrasion resistance of the resin foam, pure MDI is preferred.

[0059] The urethane prepolymer (a2) is a polymer obtained by reacting a polyol compound with a polyisocyanate compound (x) in an amount such that the molar equivalent ratio of isocyanate groups is in excess relative to the hydroxyl groups of the polyol compound, and has two or more isocyanate groups in one molecule. By using such a prepolymer as a raw material compound, the reaction for producing a flexible polyurethane foam proceeds easily, and a resin foam having excellent homogeneity and small variations in density and cell structure can be easily obtained.

[0060] The urethane prepolymer (a2) is preferably a polyether-based urethane prepolymer which is a reaction product between a polyether polyol and a polyisocyanate compound (x) and has two or more isocyanate groups in one molecule.

[0061] Both polyether polyols and polyester polyols can impart hydrophilicity, but polyether polyols have better hydrolysis resistance than polyester polyols. From the viewpoint of durability of the resin foam (flexible polyurethane foam) as a carrier, polyether polyols are preferred to polyester polyols.

[0062] Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. These are obtained by ring-opening polymerization of cyclic ether compounds, ethylene oxide (EO), propylene oxide (PO), and tetrahydrofuran, respectively. The polyether polyol may be used alone or in combination of two or more kinds. In addition, it may be a copolymer of the cyclic ether compound, and in terms of flexibility, hydrophilicity, and the like of the produced resin foam, EO-PO copolymer is particularly preferred. The monomer composition ratio of EO to PO in the EO-PO copolymer is preferably 70 / 30 to 20 / 80, more preferably 65 / 35 to 25 / 75, and further preferably 60 / 40 to 30 / 70, in terms of mass ratio.

[0063] From the viewpoint of ease of handling during production of the urethane prepolymer (a2), the polyether polyol preferably has a viscosity that is not too high, and a number average molecular weight of preferably 1,000 to 8,000, more preferably 2,000 to 7,000, and even more preferably 2,500 to 5,000.

[0064] The polyisocyanate compound (x) to be reacted with the polyether polyol is not particularly limited, and may be the same as the polyisocyanate compound (a1). The polyisocyanate compound (x) may be one type alone or two or more types may be used in combination. Among these, TDI and / or MDI are preferably used from the viewpoint of the chemical resistance and abrasion resistance of the resin foam to be produced. Furthermore, the polyisocyanate compound (x) used in the synthesis of the urethane prepolymer (a2) may be the same as or different from the polyisocyanate compound (a1).

[0065] The content of the polyisocyanate compound (a1) in Liquid A is set in consideration of the viscosity of Liquid A, the hydrophilicity of the flexible polyurethane foam, etc., but it is preferably 30 parts by mass or less, more preferably 1 to 25 parts by mass, and still more preferably 2 to 20 parts by mass with respect to 100 parts by mass of the urethane prepolymer (a2).

[0066] Liquid A may further contain an inorganic filler as required. By using the inorganic filler, the specific gravity of the produced resin foam can be adjusted, and when a carrier made using the resin foam is put into water, it can be quickly sedimented in the water. Examples of the inorganic filler include barium sulfate, calcium carbonate, talc, silica, alumina, activated carbon, zeolite, etc. The inorganic filler may be used alone or in combination of two or more. Among these, barium sulfate is preferred from the viewpoints of dispersibility in Liquid A and the specific gravity of the produced resin foam, etc.

[0067] From the viewpoint of uniform dispersibility in the produced resin foam, etc., the inorganic filler preferably has an average particle size of 0.1 to 100 μm, more preferably 0.5 to 70 μm, and still more preferably 1 to 50 μm. In addition, the "average particle size" referred to in this specification refers to the particle size (D 50 ) at the integrated value of 50% in the particle size distribution determined by the laser diffraction / scattering method. Specifically, it is the D 50 value measured using a laser diffraction / scattering type particle size distribution measuring device "MT3300" (manufactured by Microtrac Bell Corporation).

[0068] When Liquid A contains an inorganic filler, the content of the inorganic filler is appropriately adjusted according to the physical properties such as the specific gravity of the produced resin foam, etc., but it is preferably 30 parts by mass or less, more preferably 1 to 25 parts by mass, and still more preferably 2 to 20 parts by mass with respect to 100 parts by mass of the urethane prepolymer.

[0069] The curing agent (b1) has the effect of crosslinking and curing the polyisocyanate compound (a1) and the urethane prepolymer (a2), and is sometimes called a crosslinking agent. Examples of the curing agent (b1) include water; polyhydric alcohols such as glycerin, 1,4-butanediol, and diethylene glycol; and amine compounds such as ethanolamines and polyethylene polyamines. In addition, polyols obtained by ring-opening polymerization of the polyhydric alcohols with ethylene oxide, propylene oxide, and the like, and compounds obtained by adding a small amount of propylene oxide to the amine compounds are also included. These may be used alone or in combination of two or more. Among the curing agents (b1), water is preferred from the viewpoints of reactivity, ease of handling, cost, and the like. The content of the curing agent (b1) in the liquid B can be appropriately set in consideration of the flexibility, elasticity, strength, and the like of the resin foam.

[0070] The foaming agent (b2) may be the same as the foaming agent (f2) constituting the resin foam composition (1) described above. Among these, it is preferable to use water alone from the viewpoints of ease of handling, cost, environmental protection, etc. The content of the blowing agent (b2) in the liquid B can be appropriately set taking into consideration the foaming rate (foam generation rate) in the production of a resin foam, the mixing state of the liquids A and B, and the like.

[0071] As described above, water functions both as a curing agent and a foaming agent, and is suitable as a raw material compound for Liquid B. In this case, the content of water used as the curing agent (b1) and the foaming agent (b2) in Liquid B is preferably 20 to 90 parts by mass, more preferably 25 to 85 parts by mass, and even more preferably 30 to 80 parts by mass, relative to 100 parts by mass in total of the polyisocyanate compound (a1) and the urethane prepolymer (a2) in Liquid A, which are synthetic raw materials for polyurethane.

[0072] If necessary, solution A and / or solution B may contain a solvent, as well as additives known in the production of flexible polyurethane foams, such as a foam stabilizer, a colorant, a catalyst, etc., within the range that does not impair the effects of the present invention. As the foam stabilizer, the same foam stabilizer as that constituting the above-mentioned resin foam composition (1) can be used.

[0073] The resin foam can be produced from the resin foam composition (2) by reacting the resin foam composition (2) containing a carbodiimide group-containing compound obtained by mixing liquid A and liquid B, and a flexible polyurethane foam can be obtained as the resin foam. For example, the resin foam can be obtained by a method in which liquid A and liquid B are mixed using a mixing head and then subjected to cast foam molding. From the viewpoint of obtaining a homogeneous resin foam having a desired cell structure, the mixing ratio of liquid A to liquid B is preferably 51 / 49 to 79 / 21 by mass, more preferably 53 / 47 to 77 / 23, and further preferably 55 / 45 to 75 / 25. The resin foam can be used as a microorganism-immobilizing carrier for water treatment by, for example, cutting a block (slab) of the resin foam into a desired size and shape.

[0074] <Resin foam composition (3)> The resin foam composition (3) usually constitutes a two-liquid type flexible polyurethane foam consisting of a liquid C containing a carbodiimide group-containing compound (c1) and a urethane prepolymer (c2) and a liquid D containing a curing agent (d1) and a blowing agent (d2). In the embodiment (3-1) above, the carbodiimide group-containing compound (c1) in the liquid C contains a carbodiimide-modified polyisocyanate compound. The liquid C may contain a polyisocyanate compound in addition to the carbodiimide-modified polyisocyanate compound. The liquid C and / or the liquid D may contain a carbodiimide group-containing compound other than the carbodiimide-modified polyisocyanate compound. When a resin foam raw material composition containing a carbodiimide group-containing compound in such a form is used, a resin foam having excellent chemical resistance and abrasion resistance can also be produced.

[0075] From the viewpoint of the effect of improving the chemical resistance and abrasion resistance of the resin foam by adding the carbodiimide group-containing compound, the amount of the carbodiimide group-containing compound added is preferably 0.005 to 25.0 parts by mass, more preferably 0.01 to 15.0 parts by mass, even more preferably 0.02 to 10.0 parts by mass, and still more preferably 0.04 to 8.0 parts by mass, relative to 100 parts by mass combined of Liquid C and Liquid D (excluding the carbodiimide group-containing compound).

[0076] As described above in the section on <Carbodiimide group-containing compound>, examples of the carbodiimide-modified polyisocyanate compound include those synthesized by decarboxylation condensation reaction of a polyisocyanate compound, and these may be used alone or in combination of two or more. Among these, from the viewpoint of the chemical resistance and abrasion resistance of the produced resin foam, carbodiimide-modified TDI and / or carbodiimide-modified MDI are preferably used, and carbodiimide-modified MDI is more preferably used.

[0077] The content of the carbodiimide-modified polyisocyanate compound in Liquid C is set in consideration of the viscosity of Liquid C, the hydrophilicity of the flexible polyurethane foam, and the like, and is preferably 30 parts by mass or less, more preferably 1 to 25 parts by mass, and even more preferably 2 to 20 parts by mass, per 100 parts by mass of the urethane prepolymer (c2).

[0078] As the urethane prepolymer (c2), the same urethane prepolymer (a2) constituting the above-mentioned resin foam composition (2) can be used.

[0079] Explanations about the curing agent (d1), the foaming agent (d2), and other components (solvents and additives) that may be contained in Liquid C and / or Liquid D are omitted here because they are similar to those about the curing agent (b1), the foaming agent (b2), and other components that may be contained in Liquid A and / or Liquid B of the resin foam composition (2). In this case, Liquid C corresponds to Liquid A, and Liquid D corresponds to Liquid B.

[0080] The resin foam can be produced from the resin foam composition (3) by reacting the resin foam composition (3) containing a carbodiimide group-containing compound, which is a mixture of the liquids C and D, to obtain a flexible polyurethane foam as the resin foam. The mixture of the liquids C and D can be carried out in the same manner as the mixture of the liquids A and B of the resin foam composition (2). EXAMPLES

[0081] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

[0082] [Manufacturing of resin foam] As a representative example of a method for producing a resin foam, a method for producing the resin foam from the resin foam composition (2) or (3) was used.

[0083] In the following Examples and Comparative Examples, the raw materials used in the resin foam composition (2) are shown in detail below. ≪Liquid A≫ <Polyisocyanate compound (a1)> TDI: "Coronate (registered trademark) T-80", manufactured by Tosoh Corporation, 2,4-TDI / 2,6-TDI molar ratio: 80 / 20 Crude MDI (1): "Cosmonate (registered trademark) M-200", manufactured by Kumho Mitsui Chemicals, Inc. Crude MDI (2): "Millionate (registered trademark) MR-200", manufactured by Tosoh Corporation Pure MDI (4,4'-MDI): Millionate (registered trademark) MT, manufactured by Tosoh Corporation <Urethane prepolymer (a2)> TDI modified EO-PO copolymer (1): EO / PO mass ratio: 55 / 45, number average molecular weight of EO-PO copolymer: 2700 (theoretical value), NCO (isocyanate group) content: 4.5% by mass TDI modified EO-PO copolymer (2): EO / PO mass ratio: 37 / 63, number average molecular weight of EO-PO copolymer: 2700 (theoretical value), NCO (isocyanate group) content: 4.5% by mass <Inorganic filler> Barium sulfate; manufactured by Sakai Chemical Industry Co., Ltd., average particle size 20-30 μm, specific gravity 4.3 ≪Liquid B≫ <Hardening agent (b1)> ·water <Foaming agent (b2)> ·water <Foam stabilizer> Nonionic surfactant: "Newpol (registered trademark) PE-75" manufactured by Sanyo Chemical Industries, Ltd. <Carbodiimide group-containing compound> The amount of each ingredient is indicated as the amount of active ingredient (excluding water content). Polycarbodiimide compound (P1): "Carbodilite (registered trademark) V-06", manufactured by Nisshinbo Chemical Inc., moisture content 60% by mass Polycarbodiimide compound (P2): "Carbodilite (registered trademark) SV-02", manufactured by Nisshinbo Chemical Inc., moisture content 60% by mass Polycarbodiimide compound (P3): "Carbodilite (registered trademark) V-04", manufactured by Nisshinbo Chemical Inc., moisture content 60% by mass Polycarbodiimide compound (P4): "Carbodilite (registered trademark) V-04PF", manufactured by Nisshinbo Chemical Inc., moisture content 0% by mass <Catalyst> Amine catalyst: Niax® catalyst A-1, manufactured by Momentive Performance Materials

[0084] Example 1 Liquid A was prepared by mixing with stirring 53.3 kg of TDI as the polyisocyanate compound (a1), 400 kg of the TDI-modified EO-PO copolymer (1) as the urethane prepolymer (a2), and 50.0 kg of an inorganic filler. Furthermore, 350 kg of water as a curing agent (b1) and a foaming agent (b2), 7.0 kg of a foam stabilizer, and 2.2 kg of a polycarbodiimide compound (P1) as a carbodiimide group-containing compound (0.88 kg in terms of active ingredient: 0.1 part by mass per 100 parts by mass of the total of solutions A and B (excluding the carbodiimide group-containing compound)) were mixed with stirring to prepare solution B. The prepared liquid A and liquid B were pumped from their respective tanks to a mixing head in a mixing ratio of 60 / 40 (liquid A / liquid B). The mixed liquid of liquid A and liquid B was discharged from the mixing head and subjected to cast foaming to produce a resin foam (flexible polyurethane foam).

[0085] (Examples 2 to 6, 8 and 9, Comparative Example 1) A resin foam (flexible polyurethane foam) was produced in the same manner as in Example 1, except that the types and amounts of carbodiimide group-containing compounds shown in Table 1 below were used.

[0086] Example 7 Liquid A was prepared by mixing with stirring 53.3 kg of TDI as the polyisocyanate compound (a1), 400 kg of the TDI-modified EO-PO copolymer (2) as the urethane prepolymer (a2), and 50.0 kg of an inorganic filler. Furthermore, 350 kg of water as a curing agent (b1) and a foaming agent (b2), 15.5 kg of a foam stabilizer, and 24.5 kg of a polycarbodiimide compound (P2) as a carbodiimide group-containing compound (9.8 kg in terms of active ingredient: 1.0 part by mass per 100 parts by mass of the total of solutions A and B (excluding the carbodiimide group-containing compound)), and 5.0 kg of a catalyst were mixed and stirred to prepare solution B. The prepared liquid A and liquid B were pumped from their respective tanks to a mixing head in a mixing ratio of 60 / 40 (liquid A / liquid B). The mixed liquid of liquid A and liquid B was discharged from the mixing head and subjected to cast foaming to produce a resin foam (flexible polyurethane foam).

[0087] Example 10 53.3 kg of TDI as the polyisocyanate compound (a1), 400 kg of TDI-modified EO-PO copolymer (2) as the urethane prepolymer (a2), 50.0 kg of inorganic filler, and 8.4 kg of the polycarbodiimide compound (P4) as the carbodiimide group-containing compound were mixed with stirring to prepare liquid A. Furthermore, 350 kg of water, 14.9 kg of a foam stabilizer, and 4.7 kg of a catalyst were mixed with stirring to prepare a liquid B as a hardener (b1) and a foaming agent (b2). The prepared liquid A and liquid B were pumped from their respective tanks to a mixing head in a mixing ratio of 60 / 40 (liquid A / liquid B). The mixed liquid of liquid A and liquid B was discharged from the mixing head and subjected to cast foaming to produce a resin foam (flexible polyurethane foam).

[0088] Example 11 Liquid A was prepared by mixing with stirring 26.5 kg of TDI and 36.7 kg of crude MDI (1) as the polyisocyanate compound (a1), 400 kg of the TDI-modified EO-PO copolymer (1) as the urethane prepolymer (a2), and 50.0 kg of an inorganic filler. Furthermore, 350 kg of water as a curing agent (b1) and a foaming agent (b2), 7.0 kg of a foam stabilizer, and 22.8 kg of a polycarbodiimide compound (P2) as a carbodiimide group-containing compound (9.1 kg in terms of active ingredient: 1.0 part by mass per 100 parts by mass of the total of solutions A and B (excluding the carbodiimide group-containing compound)) were mixed with stirring to prepare solution B. The prepared liquid A and liquid B were pumped from their respective tanks to a mixing head in a mixing ratio of 60 / 40 (liquid A / liquid B). The mixed liquid of liquid A and liquid B was discharged from the mixing head and subjected to cast foaming to produce a resin foam (flexible polyurethane foam).

[0089] Example 12 A resin foam (flexible polyurethane foam) was produced in the same manner as in Example 11, except that 28.8 kg of TDI and 40.0 kg of pure MDI were used as the polyisocyanate compound (a1).

[0090] (Example 13) A resin foam (flexible polyurethane foam) was produced in the same manner as in Example 11, except that 86.7 kg of pure MDI as the polyisocyanate compound (a1) and 51.9 kg of inorganic filler were used.

[0091] Comparative Example 2 A resin foam (flexible polyurethane foam) was produced in the same manner as in Example 11, except that 28.8 kg of TDI and 40.0 kg of crude MDI (2) were used as the polyisocyanate compound (a1) and no carbodiimide group-containing compound was used.

[0092] In the following examples, the raw materials used in the resin foam composition (3) are shown in detail below. ≪Liquid C≫ <Polyisocyanate compounds> TDI: Same as that used in solution A Crude MDI (2): Same as that used in solution A <Carbodiimide group-containing compound (c1) (carbodiimide-modified polyisocyanate compound)> Carbodiimide-modified MDI: "Coronate (registered trademark) MX" manufactured by Tosoh Corporation, a carbodiimide-modified form of 4,4'-MDI <Urethane prepolymer (c2)> TDI modified EO-PO copolymer (1): Same as that used in solution A <Inorganic filler> Barium sulfate: Same as that used in solution A ≪Liquid D≫ <Hardening agent (d1)> ·water <Foaming agent (d2)> ·water <Foam stabilizer> Nonionic surfactant: Same as that used in solution B

[0093] Example 14 Liquid C was prepared by stirring and mixing 29.1 kg of TDI and 4.3 kg of crude MDI (2) as polyisocyanate compounds, 42.1 kg of carbodiimide-modified MDI as a carbodiimide group-containing compound (c1) (5.0 parts by mass per 100 parts by mass of the total of Liquids C and D (excluding the carbodiimide group-containing compound)), 400 kg of urethane prepolymer (c2), and 51.0 kg of inorganic filler. Furthermore, 350 kg of water as the hardener (d1) and the foaming agent (d2), and 7.0 kg of a foam stabilizer were mixed with stirring to prepare a D liquid. The prepared liquids C and D were pumped from their respective tanks to a mixing head in a mixing ratio of 60 / 40 (liquid C / liquid D). The mixture of liquids C and D was discharged from the mixing head and subjected to cast foaming to produce a resin foam (flexible polyurethane foam).

[0094] [Physical property evaluation] For each of the resin foams produced in the above Examples and Comparative Examples, test pieces were prepared as described below and evaluated for the following items. The evaluation results are summarized in Tables 1 and 2 below.

[0095] (Preparation of test specimens) The produced block of resin foam was sliced ​​horizontally from the center to obtain a sheet, which was then punched out to prepare a rectangular parallelepiped test piece (1) measuring 100 mm x 100 mm and 10 mm thick (when swollen with water). In addition, cubic test pieces (2) each having a side length of 10 mm (when swollen with water) were cut out from the sheet-like body, and 20 of these were dried in a dryer at 110°C for 2 hours and used for evaluation of chemical resistance and abrasion resistance.

[0096] <Absolutely dry density> The mass of the test piece (1) was measured using an electronic balance, and then it was dried in a dryer at 110° C. The state in which no further loss in mass was observed was regarded as being completely dry. The length of each side of the rectangular parallelepiped test piece (1) in the bone-dry state was measured with a caliper (resolution 0.05 mm). The volume calculated as the product of the lengths of each side was the bone-dry volume V. d It was considered that. The mass M of the test piece (1) in the absolute dry state obtained as above d Let V be the volume in the dry state. d The value divided by this was taken as the bone dry density.

[0097] <Swelling density> The test piece (1) was immersed in pure water at 25°C for 1 hour, and the length of each side of the rectangular parallelepiped test piece (1) was measured with a vernier caliper (resolution 0.05 mm) while it was laid flat and immersed in pure water. The volume calculated as the product of the lengths of each side was the volume V of the test piece (1) when swollen in water. w It was considered that. The bone dry mass M d The volume V of the water-swollen w The value obtained by dividing the density by the mass was determined as the swelling density.

[0098] <Volume swelling ratio> The volume V of the bone dry state d Volume V when swollen in water w The ratio was calculated as the volume swelling ratio. If the volume swelling ratio is 110% or more, it can be said that the material has good water swelling properties.

[0099] <Average number of pores> The central portion of the surface of the test piece (1) after the volume measurement when swollen in water was performed as described above was colored with red ink. A ruler was placed on the colored portion, and a photograph was taken so that the colored portion and the scale of the ruler were included. In the enlarged image of the photograph, the number of pores observed on any line parallel to the ruler within a range of 25 mm intervals of the scale at any point on the ruler was counted. The same measurement was performed at three arbitrary points, and the average of the number of pores measured three times was taken as the average number of pores per 25 mm when swollen in water. It was confirmed that the average number of pores when swollen with water was 9 to 40 pores / 25 mm for all of the resin foams of the Examples and Comparative Examples.

[0100] <Average pore diameter> After measuring the volume when swollen in water, an arbitrary location near the center of the surface of the test piece (1) was observed with a microscope. The long and short diameters of one pore in the observed image were measured, and the pore was considered to be a perfect circle with the average value of the long and short diameters as the diameter. In the same manner, the diameters of a total of 50 pores were determined when each pore was considered to be a perfect circle. The average value of these diameters was taken as the average pore diameter when swollen in water. It was confirmed that the resin foams of all the Examples and Comparative Examples had an average pore size of 0.20 to 2.00 mm when swollen with water. As a representative example, the resin foam produced in Example 1 was observed with an electron microscope to determine its cell structure, which was confirmed to have an interconnected pore structure and a wall structure.

[0101] <Chemical resistance> The total mass of the 20 test pieces (2) in an absolutely dry state was measured, and this was called the pre-test dry mass (M 1 ) was decided. Twenty test pieces (2) and 100 mL of an aqueous sodium hypochlorite solution with an effective chlorine concentration of 0.2% by mass were placed in a 250 mL plastic bottle, and the bottle was gently swirled to mix well, and the test piece (2) was immersed in the aqueous sodium hypochlorite solution. The plastic bottle was then capped and allowed to stand at room temperature (25°C) for 2 hours (Test 1). For each of the resin foams produced in the above Examples and Comparative Examples, the test piece (2) was compatible with the sodium hypochlorite aqueous solution and sank into the aqueous solution. The contents of the plastic bottle were emptied onto a wire mesh to take out the test piece (2). The test piece (2) was immersed in a plastic cup containing 2 L of tap water for 10 seconds, and then emptied onto the wire mesh again to take out the test piece (2), thereby washing it. After repeating this washing operation three times, the test piece (2) was transferred to a petri dish. After drying in a dryer at 110°C for 2 hours, the total mass of the test piece (2) was measured, and this was designated as the post-test dry mass (M 2 ) was decided. Dry mass before test (M 1 ) to the post-test dry mass (M 2 ) ratio (M 2 / M 1 ) was defined as the mass residual rate (1) in the chemical resistance evaluation test (Test 1). In the following Tables 1 and 2, the numerical values ​​of the mass residual rate (1) are shown as evaluation indexes of chemical resistance. If the mass residual rate (1) is more than 75%, it can be said that the wear of the carrier when immersed in a water treatment chemical is suppressed and the chemical resistance is good.

[0102] <Wear resistance> Twenty test pieces (2) after (Test 1) and 200 mL of pure water were placed in a cylindrical container (inner diameter 105 mm, height 100 mm) with waterproof sandpaper (#100) attached to the inner surface, and the test pieces (2) were lightly mixed together using a medicine spoon to immerse them in the pure water. An agitator blade ("General-purpose agitator blade turbine for SUS tip", manufactured by AS ONE Corporation; three-blade turbine blade, diameter 66 mm, height 14 mm) was attached to an agitator shaft with a diameter of 8 mm and positioned at a distance of 10 mm from the center of the bottom of the container. The mixture was stirred at room temperature (25°C) for 24 hours at a rotation speed of 400 rpm (Test 2). The contents of the container were poured onto a wire mesh to separate the water and the shavings from test (2), and the remaining test piece (2) was taken out. The test piece (2) was washed by immersing it in a polycup containing 2 L of tap water for 10 seconds, pouring it onto the wire mesh again, and taking out the test piece (2). This washing operation was repeated three times, and then the test piece (2) was transferred to a petri dish. After drying in a dryer at 110°C for 2 hours, the total mass of the test piece (2) was measured, and this was called the post-test dry mass (M 3 ) was decided. Dry mass before chemical resistance evaluation test (Test 1) (M 1 ) to the post-test dry mass (M 3 ) ratio (M 3 / M 1 ) was defined as the mass remaining rate (2) in the abrasion resistance evaluation test (Test 2). In the following Tables 1 and 2, the numerical values ​​of the mass remaining rate (2) are shown as an evaluation index of abrasion resistance. If the mass residual rate (2) exceeds 55%, it can be said that wear of the carrier caused by use in a water treatment tank is suppressed and the carrier has good wear resistance.

[0103] [Table 1]

[0104] [Table 2]

[0105] As can be seen from the results shown in Tables 1 and 2, it was confirmed that the chemical resistance and abrasion resistance can be improved by blending a carbodiimide group-containing compound in the raw material composition of a resin foam. When MDI was used as the polyisocyanate compound (Examples 11 to 14), and when carbodiimide-modified MDI was used as the carbodiimide group-containing compound (Example 14), resin foams (carriers) with particularly excellent chemical resistance and abrasion resistance were obtained. Note that, in IR spectrum measurement, the resin foams of Examples 1 to 14 showed a high IR spectrum at wave numbers of 2100 to 2200 cm. -1However, in the resin foams of Comparative Examples 1 and 2, no absorption peaks due to carbodiimide groups were detected. Therefore, it can be said that the resin foam according to the embodiment of the present invention can form a microorganism-immobilized carrier for water treatment that has excellent hydrophilicity and water swelling properties, as well as excellent chemical resistance and abrasion resistance.

Claims

1. The foam is made of a resin containing a carbodiimide group. The resin foam is obtained by foaming and curing a resin foam composition, The resin foam composition comprises a carbodiimide group-containing compound in an amount of 0.02 to 10.0 parts by mass per 100 parts by mass excluding the carbodiimide group-containing compound.

2. 2. The microorganism-immobilizing carrier for water treatment according to claim 1, wherein the resin foam is a flexible polyurethane foam.

3. 3. The microorganism-immobilizing carrier for water treatment according to claim 1, which has a volume swelling ratio, expressed as the ratio of the volume when swollen with water to the volume in an absolutely dry state, of 110 to 1000%.

4. The swelling density when swollen with water is 20.0 to 70.0 kg / m 3 The microorganism-immobilized carrier for water treatment according to any one of claims 1 to 3,

5. 5. The microorganism-immobilizing carrier for water treatment according to claim 1, wherein the average number of pores when swollen with water is 9 to 40 pores / 25 mm.

6. A resin foam for use as a microorganism immobilization carrier for water treatment, comprising: The resin foam is obtained by foaming and curing a resin foam composition, and contains a carbodiimide group, the resin foam composition contains a carbodiimide group-containing compound in an amount of 0.02 to 10.0 parts by mass per 100 parts by mass excluding the carbodiimide group-containing compound; A resin foam having a volume swelling ratio, expressed as the ratio of the volume when swollen with water to the volume in an absolutely dry state, of 110 to 1000%.

7. The resin foam according to claim 6 , wherein the resin foam is a flexible polyurethane foam.

8. The swelling density when swollen with water is 20.0 to 70.0 kg / m 3 The resin foam according to claim 6 or 7,

9. The resin foam according to any one of claims 6 to 8, wherein the average number of pores when swollen with water is 9 to 40 pores / 25 mm.

10. The resin foam according to any one of claims 6 to 9, wherein a test piece of the resin foam is subjected to the following (Test 1), washed with water, and dried at 110 ° C. for 2 hours, and the mass residual rate of the test piece is more than 75%. (Test 1) A cubic test piece having a side length of 10 mm when swollen in water was immersed in an aqueous sodium hypochlorite solution having an effective chlorine concentration of 0.2% by mass at 25° C. for 2 hours.

11. The resin foam according to any one of claims 6 to 10, wherein a test piece of the resin foam is subjected to the following (Test 2), washed with water, and dried at 110 ° C. for 2 hours, and the mass residual rate of the test piece is more than 55%. (Test 2) Twenty cubic test pieces, each 10 mm on a side, were immersed in an aqueous solution of sodium hypochlorite with an effective chlorine concentration of 0.2% by mass for 2 hours. The test pieces were then washed with water and dried at 110°C for 2 hours. The test pieces were then placed in 200 mL of pure water in a cylindrical container (inner diameter 105 mm, height 100 mm) with waterproof sandpaper (#100) attached to the inner surface. A stirring blade (three-blade turbine blade, diameter 66 mm, height 14 mm, shaft diameter 8 mm) was placed at a distance of 10 mm from the center of the bottom of the container, and the test pieces were stirred at a rotation speed of 400 rpm at 25°C for 24 hours.

12. A part of a resin foam composition for producing a resin foam for use as a microorganism-immobilized carrier for water treatment, The resin foam composition comprises a carbodiimide group-containing compound in an amount of 0.02 to 10.0 parts by mass per 100 parts by mass excluding the carbodiimide group-containing compound.

13. The resin foam is a flexible polyurethane foam produced from a resin foam composition (1) containing a polyisocyanate compound (e1), a polyol compound (f1), and a blowing agent (f2), The resin foam raw material composition according to claim 12, which is a part of the resin foam composition (1), and which contains the polyol compound (f1), the blowing agent (f2), and a carbodiimide group-containing compound.

14. The resin foam is a flexible polyurethane foam produced from a resin foam composition (1) containing a polyisocyanate compound (e1), a polyol compound (f1), and a blowing agent (f2), The resin foam raw material composition according to claim 12, which is a part of the resin foam composition (1), and contains the polyisocyanate compound (e1) and a carbodiimide group-containing compound.

15. The resin foam is a flexible polyurethane foam produced from a resin foam composition (2) containing a polyisocyanate compound (a1), a urethane prepolymer (a2), a curing agent (b1), and a foaming agent (b2), The resin foam raw material composition according to claim 12, which is a part of the resin foam composition (2), and contains the curing agent (b1), the blowing agent (b2), and a carbodiimide group-containing compound.

16. The resin foam is a flexible polyurethane foam produced from a resin foam composition (2) containing a polyisocyanate compound (a1), a urethane prepolymer (a2), a curing agent (b1), and a foaming agent (b2), The resin foam raw material composition according to claim 12, which is a part of the resin foam composition (2), and contains the polyisocyanate compound (a1), the urethane prepolymer (a2), and a carbodiimide group-containing compound.

17. The resin foam is a flexible polyurethane foam produced from a resin foam composition (3) containing a carbodiimide group-containing compound (c1), a urethane prepolymer (c2), a curing agent (d1), and a foaming agent (d2), A part of the resin foam composition (3), comprising the carbodiimide group-containing compound (c1) and the urethane prepolymer (c2), The resin foam raw material composition according to claim 12, wherein the carbodiimide group-containing compound (c1) includes a carbodiimide-modified polyisocyanate compound.

18. The resin foam raw material composition according to any one of claims 15 to 17, wherein the urethane prepolymer (a2) or (c2) is a reaction product of a polyether polyol and a polyisocyanate compound (x) and is a polyether-based urethane prepolymer having two or more isocyanate groups in one molecule.

19. The resin foam raw material composition according to claim 18, wherein the polyether polyol is an ethylene oxide-propylene oxide copolymer.

20. The resin foam raw material composition according to any one of claims 15 to 19, wherein the curing agent (b1) or (d1) is water.

21. The resin foam raw material composition according to any one of claims 13 to 20, wherein the blowing agent (f2), (b2) or (d2) is water.

22. A method for producing a resin foam using the resin foam raw material composition according to claim 13 or 14, comprising reacting the resin foam composition (1) containing a carbodiimide group-containing compound to obtain a flexible polyurethane foam.

23. A method for producing a resin foam using the resin foam raw material composition according to claim 15 or 16, comprising reacting the resin foam composition (2) containing a carbodiimide group-containing compound to obtain a flexible polyurethane foam.

24. A method for producing a resin foam using the resin foam raw material composition according to claim 17, comprising reacting the resin foam composition (3) containing a carbodiimide group-containing compound to obtain a flexible polyurethane foam.

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