Marine-biodegradation accelerator

1 . A marine biodegradation accelerator comprising a compound which contains one or more anion, including an anion having six or more carbon atoms and three or more oxygen atoms, and a metal cation having a valence of two or more, the anion and the metal cation being bonded together via an ionic bond,

wherein the compound has a contact angle of 30° or more when 30 seconds have elapsed after a water droplet is placed on particles made of the compound, wherein

the anion having six or more carbon atoms and three or more oxygen atoms comes from a water-soluble anionic polymer;

the accelerator is obtained by subjecting a crosslinked polymer comprised of the water-soluble anionic polymer and the metal cation having a valence of two or more to hydrophobization; and

the water-soluble anionic polymer has at least one anionic functional group selected from the group consisting of carboxyl, hydroxyl, sulfonic acid, sulfate and phosphate ester groups and also anionic functional groups having a structure in which a hydrogen atom on any of said groups is substituted with a monovalent metal.

2 . The marine biodegradation accelerator of claim 1 , wherein the accelerator has a water absorption per 100 g and an oil absorption per 100 g such that the water absorption is lower than the oil absorption.

3 . The marine biodegradation accelerator of claim 1 wherein, at 25° C., the accelerator is insoluble in water and soluble in a 3 wt % aqueous solution of sodium chloride.

4 . The marine biodegradation accelerator of claim 1 wherein, letting SD1 be the percent transmittance of 560 nm wavelength light by the accelerator 168 hours after being dispersed to a concentration of 0.1 wt % in a 3 wt % aqueous solution of sodium chloride and WD1 be the percent transmittance of 560 nm wavelength light by the accelerator at room temperature 24 hours after being dispersed in water to a concentration of 0.1 wt %, the ratio WD1/SD1 is not more than 0.9.

5 . The marine biodegradation accelerator of claim 1 , wherein the accelerator is in the form of particles.

6 . The marine biodegradation accelerator of claim 1 , wherein the metal cation is of at least one type selected from the group consisting of calcium, magnesium, aluminum, zinc, iron, copper and barium ions.

7 . The marine biodegradation accelerator of claim 1 , wherein hydrophobization is carried out using at least one hydrophobizing agent selected from the group consisting of monovalent carboxylic acid salts, monovalent amino acid derivative salts, monovalent sulfate ester salts, monovalent sulfonic acid salts, monovalent phosphate ester salts and monovalent lactic acid ester salts.

8 . A marine biodegradation accelerator, comprising a compound which contains one or more anion, including an anion having six or more carbon atoms and three or more oxygen atoms, and a metal cation having a valence of two or more, the anion and the metal cation being bonded together via an ionic bond, wherein the compound has a contact angle of 30° or more when seconds have elapsed after a water droplet is placed on particles made of the compound,

the anion having six or more carbon atoms and three or more oxygen atoms is a monovalent anion having six or more carbon atoms and three or more oxygen atoms or an anion having two monovalent anionic substituents which has six or more carbon atoms and three or more oxygen atoms,

wherein the monovalent anion having six or more carbon atoms and three or more oxygen atoms is a monovalent anion obtained by introducing one monovalent anionic substituent selected from a carboxylic acid anion, a sulfonic acid anion, a sulfuric acid anion, and a phosphoric acid anion into a monohydric alcohol having 6 to 30 carbon atoms, a monoamino compound having 6 to 30 carbon atoms, or a (poly)alkylene glycol ether having an HLB value of 16 or less, or is derived from an amino acid derivative salt having 6 to 30 carbon atoms or a sulfonic acid salt having 6 to 30 carbon atoms, and

the anion having two monovalent anionic substituents which has six or more carbon atoms and three or more oxygen atoms is an anion obtained by introducing two monovalent anionic substituent selected from a carboxylic acid anion, a sulfonic acid anion, a sulfuric acid anion, and a phosphoric acid anion into a dihydric alcohol having 6 to 30 carbon atoms, a (poly)alkylene glycol selected from (poly)propylene glycol, (poly)butylene glycol, (poly)tetramethylene ether glycol, (poly)hexamethylene ether glycol and (poly)octamethylene ether glycol, or a copolymer thereof, or is derived from a dicarboxylic acid salt having 6 to 30 carbon atoms or a disulfonic acid salt having 6 to 30 carbon atoms.

9 . A resin composition comprising the marine biodegradation accelerator of claim 1 and a resin.

10 . The resin composition of claim 9 , wherein the resin is a biodegradable resin.

11 . A molded or formed body obtained from the resin composition of claim 9 .

12 . A surface modifier comprising the marine biodegradation accelerator of claim 1 .

13 . The marine biodegradation accelerator of claim 1 wherein the water-soluble anionic polymer is at least one type of polysaccharide monovalent salt selected from among monovalent salts of alginic acid, monovalent salts of carboxymethylcellulose, monovalent salts of modified starches, monovalent salts of hyaluronic acid, monovalent salts of chondroitin sulfuric acid, monovalent salts of glucosaminoglycan derivatives, monovalent salts of cellulose derivatives, monovalent salts of starch derivatives, monovalent salts of chitosan derivatives and monovalent salts of chitin derivatives.

14 . The marine biodegradation accelerator of claim 1 wherein the water-soluble anionic polymer is at least one type of polysaccharide monovalent salt selected from among sodium alginate, potassium alginate, ammonium alginate, sodium carboxymethylcellulose, potassium carboxymethylcellulose, ammonium carboxymethylcellulose, starch sodium octenyl succinate, starch sodium glycolate, sodium hyaluronate and sodium chondroitin sulfate.

15 . The marine biodegradation accelerator of claim 8 wherein the monovalent anion having six or more carbon atoms and three or more oxygen atoms is a monovalent anion obtained by introducing one monovalent anionic substituent selected from a carboxylic acid anion and a sulfonic acid anion into a (poly)alkylene glycol ether having an HLB value of 16 or less, or is derived from an amino acid derivative salt having 6 to 30 carbon atoms or a sulfonic acid salt having 6 to 30 carbon atoms, and

the anion having two monovalent anionic substituents which has six or more carbon atoms and three or more oxygen atoms is an anion obtained by introducing two monovalent anionic substituent selected from a carboxylic acid anion and a sulfonic acid anion into (poly)propylene glycol or (poly)butylene glycol, or is derived from a dicarboxylic acid salt having 6 to 30 carbon atoms or a disulfonic acid salt having 6 to 30 carbon atoms.