PURGE AGENT AND METHOD FOR PURGE A MOLDING MACHINE USING THE SAME

Abstract

A purging agent of the present invention comprises a resin composition containing a hydrophilic resin (A), water (B), and a basic compound (C); the mass ratio (A) / (B) of the hydrophilic resin (A) to water (B) is 66 / 34 to 90 / 10, and the content of the basic compound (C) is 0.25 to 7 parts by mass relative to the 100 parts by mass of the hydrophilic resin (A).

Description

PURGE AGENT AND METHOD FOR PURGE A MOLDING MACHINE USING THE SAME TECHNICAL FIELD The present invention relates to a purging agent and a method for purging a molding machine using the same, and more particularly to a purging agent with improved handling and improved safety and a method for purging a molding machine using the same. BACKGROUND OF THE INVENTION Resins with high gas barrier properties, including ethylene-vinyl alcohol copolymers (also referred to as EVOHs hereafter), are widely used in products such as films and food packaging containers. When a resin is melt-extruded into a molding machine to produce a product, resin adhesion can occur in flow passages of the molding machine (for example, the resin may adhere to the screw). If this adhered resin is left undisturbed for an extended period, it undergoes deterioration such as scaling, gelling, and decomposition. This results in products with defects such as blotches, lumps, and gels, or require a significant amount of time and material loss to remove these defects. Several purging agents have been proposed to date. For example, Patent Document 1 describes a purging agent containing a hydrophobic thermoplastic resin such as a polyolefin resin, a hydrophilic thermoplastic resin such as a saponified ethylene-vinyl acetate copolymer product, and water. Patent Document 2 describes a purging agent obtained by mixing a saponified ethylene-vinyl ester copolymer product or similar with water at a predetermined ratio. Patent Document 3 describes a purging agent containing a polyolefin resin such as low-density polyethylene (LDPE), a strongly basic compound such as an alkali metal or alkaline earth metal hydroxide, and a salt to generate free water. Documents of the related technique Patent Documents Patent Document 1: JP H10-16023A / 07 Lnn / 77n7 / E / YIAI Patent Document 2: JP2008-279623A Patent Document 3: JP2012-533647A BRIEF DESCRIPTION OF THE INVENTION Problem that will be solved by means of the invention However, the purging agents described in Patent Documents 1 and 2 are not considered capable of sufficiently removing a resin that adheres to a screw and similar component of a molding machine (this resin is also referred to as the resin to be purged hereafter). Consequently, there is still a need to improve the purging capacity. On the other hand, the purging agent described in Patent Document 3 exhibits improved purging capacity due to the strongly basic compound as one of its components. However, the purging capacity is still not satisfactory. The present invention aims to solve the problems described above, and it is an objective of the present invention to provide a purging agent that allows efficient discharge of a resin to be purged present in a molding machine and a method for purging a molding machine using the purging agent. Means to solve the problem According to the present invention, the above objective is achieved by providing: [1] a resin composition comprising: a hydrophilic resin (A); water (B); and a basic compound (C), wherein the mass ratio (A) / (B) of the hydrophilic resin (A) to water (B) is 66 / 34 to 90 / 10, and the content of the basic compound (C) is 0.25 to 7 parts by mass with respect to the 100 parts by mass of the hydrophilic resin (A); [2] the resin composition according to [1], further comprises another thermoplastic resin (D); [3] the resin composition according to [2], wherein the content of the thermoplastic resin (D) is 1 to 10000 parts by mass with respect to the 100 parts by mass of the hydrophilic resin (A); [4] the resin composition according to any of [1] to [3], wherein the hydrophilic resin (A) and water (B) are contained in the form of a water-containing hydrophilic resin obtained by mixing them; / 07 Lnn / zznz / E / YiAi [5] the resin composition according to any of [1] to [4], wherein the basic compound (C) is at least one selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, alkali metal hydroxides, ammonia, and primary to tertiary amines; [6] the resin composition according to any of [1] to [3], wherein water (B) and basic compound (C) are contained in the form of an alkaline aqueous solution obtained by mixing them together; [7] the resin composition according to [7], wherein the alkaline aqueous solution has a pH of 8 to 14; [8] the resin composition according to [6] or [7], wherein the basic compound (C) is at least one selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, ammonia, and primary to tertiary amines; [9] the resin composition according to any of [1] to [8], wherein the hydrophilic resin (A) is an ethylene-vinyl alcohol copolymer;

[10] the resin composition according to [9], wherein the ethylene vinyl alcohol copolymer has an ethylene unit content of 15 to 60% molar;

[11] a purging agent comprising the resin composition according to any of [1] to

[10] ;

[12] a purging agent comprising: a hydrophilic resin (A); and a basic compound (C), wherein the content of the basic compound (C) is 0.25 to 7 parts by mass with respect to the 100 parts by mass of the hydrophilic resin (A);

[13] the purging agent according to

[12] , further comprising another thermoplastic resin (D);

[14] the purging agent according to

[13] , wherein the content of the thermoplastic resin (D) is 1 to 10000 parts by mass relative to the 100 parts by mass of the hydrophilic resin (A);

[15] The purging agent according to any of

[12] to

[14] , wherein the basic compound (C) is at least one selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, alkali metal hydroxides, ammonia, and primary to tertiary amines;

[16] the purging agent according to any of

[12] to

[15] , wherein the hydrophilic resin (A) is an ethylene-vinyl alcohol copolymer; 7Q7 Lnn / Zznz / E / YIAI

[17] the purging agent according to

[16] , wherein the ethylene vinyl alcohol copolymer has an ethylene unit content of 15 to 60% molar;

[18] a method for purging a molding machine in which a resin to be purged is present, the method comprising the step of: supplying a resin composition containing a hydrophilic resin (A), water (B), and a basic compound (C) to the molding machine and discharging the resin composition together with the resin to be purged, wherein the mass ratio (A) / (B) of the hydrophilic resin (A) to water (B) is 90 / 10 to 66 / 34, and the content of the basic compound (C) is 0.25 to 7 parts by mass relative to the 100 parts by mass of the hydrophilic resin (A);

[19] the method according to

[18] , wherein the hydrophilic resin (A), water (B), and basic compound (C) are supplied to the molding machine in the form of the purging agent according to

[11] ;

[20] the method according to

[18] , wherein the hydrophilic resin (A) and the basic compound (C) are supplied to the molding machine in the form of the purging agent according to any of

[12] to

[17] ;

[21] the method in accordance with any of

[18] to

[20] , wherein the temperature of a melting region of the molding machine is 105°C to 230°C;

[22] the purging agent according to any of

[18] to

[21] , wherein the hydrophilic resin (A) is an ethylene-vinyl alcohol copolymer;

[23] the purging agent according to

[22] , wherein the ethylene vinyl alcohol copolymer has an ethylene unit content of 15 to 60% molar;

[24] A method for purging a molding machine in which a resin to be purged is present, the method comprising the step of: supply an alkaline aqueous solution containing water (B) and a basic compound (C) to the molding machine and discharge the alkaline aqueous solution along with the resin to be purged;

[25] the method according to

[24] , further comprising the step of supplying a hydrophilic resin (A) and another thermoplastic resin (D) to the molding machine;

[26] the purging method according to

[24] or

[25] , wherein the alkaline aqueous solution has a pH of 8 to 14. Effects of the Invention According to the present invention, a resin to be purged from a molding machine can be efficiently discharged from the molding machine. This can 7Q7 Lnn / Zznz / E / YIAI reduces defects in products obtained using the molding machine and can also reduce the time required and material loss to eliminate these defects. DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION (Resin composition) The resin composition of the present invention is a resin composition that can be used as a purging agent, for example, the purging described below of a molding machine in which a resin to be purged is present. The resin composition of the present invention contains a hydrophilic resin (A), water (B), and a basic compound (C). (Hydrophilic resin (A)) The hydrophilic resin (A) encompasses resins that have an affinity for water, and examples of hydrophilic resin (A) include resins having a water contact angle of 0° to 90°. Preferably, such hydrophilic resin (A) is, for example, at least one selected from the group comprising EVOHs, polyvinyl alcohols, polyamides, polyacrylates, polyethylene glycols, and polyacrylamides. In particular, EVOHs are more preferable from the standpoint of thermal stability and extrusion stability. When using the hydrophilic resin (A), an alkaline aqueous solution containing water (B) and the base compound (C) can be stably retained in the hydrophilic resin (A) when the purging agent composed of the resin composition of the present invention is stored at room temperature, thus ensuring user safety.Furthermore, when purging is performed, the alkaline aqueous solution is released as a result of the melting of the hydrophilic resin (A), so a sticky resin that is to be purged on a screw can be broken down and effectively removed. (EVOH) An EVOH, for example, is a copolymer obtained through the saponification of an ethylene-vinyl ester copolymer. Preparation and saponification of the ethylene-vinyl ester copolymer can be achieved using known methods. Examples of the vinyl ester used in these methods include fatty acid vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl pivalate, and vinyl versatate. In the present invention, the ethylene unit content of EVOH is, for example, preferably 15 mol% or more preferably 22 mol% or more, and even more preferably 24 mol% or more. Also, the ethylene unit content of EVOH is, by 7Q7 Lnn / Zznz / E / YIAI For example, preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. When the ethylene unit content is less than 15 mol%, it can be difficult to extrude the resulting resin composition when the melting region of a molding machine is set to a temperature of 105°C to 230°C. When the ethylene unit content is 60 mol% or less, the viscosity of the molten resin tends to be low, thus making it difficult to remove the resin that is to be purged. The ethylene unit content of EVOH can be measured, for example, by a nuclear magnetic resonance (NMR) method. In the present invention, the degree of saponification of EVOH (i.e., the degree of saponification of the vinyl ester component of EVOH) is, for example, preferably 99 mol% or more, more preferably 98 mol% or more, and even more preferably 95 mol% or more. When the degree of saponification is 99 mol% or more, the consumption of the basic compound (C) during the saponification reaction can be prevented, for example. Alternatively, the degree of saponification of EVOH is, for example, preferably 100% or less and can be 99.99% or less. The degree of saponification of EVOH can be calculated from the peak area of ​​the hydrogen atoms contained in the vinyl ester structure and the peak area of ​​the hydrogen atoms contained in the vinyl alcohol structure, as measured by 1H-NMR spectroscopy. EVOH may have one or more units derived from monomer(s) other than ethylene and vinyl ester and their saponified product, provided that the objective of the present invention is not compromised. When EVOH has the other monomer unit(s), the upper limit of the monomer unit content relative to all the structural units of EVOH is, for example, preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and most preferably 5 mol% or less. When EVOH has the unit(s) derived from the other monomer(s), its content is, for example, preferably 0.05 mol% or greater, and more preferably 0.1 mol% or greater. Examples of the other monomer include: alkenes such as propylene, butylene, pentene, and hexene; alkenes containing ester groups such as 3-acyloxy-l-propene, 3-acyloxy-l-butene, 4-acyloxy-l-butene, 3,4-diacyloxy-l-butene, 3-acyloxy-4-methyl-l-butene, 4-acyloxy-l-butene, 3,4diacyloxy-l-butene, 3-acyloxy-4-methyl-l-butene, 4-acyloxy-2-methyl-l-butene, 4-acyloxy-3-methyl-l-butene, 3,4-diacyloxy-2-methyl-l-butene, 4-acyloxy-l-pentene, 5-acyloxy-l-pentene, 4,5-diacyloxy-l-pentene, 4-acyloxy-l-hexene, 5-acyloxy-l-hexene, 6-acyloxy-l-hexene, 5,6-diacyloxy-l-hexene, l,3-diacetoxy-2-methylenepropane, and their saponified products; unsaturated acids such as acrylic acids, methacrylic acids, crotonic acid and itaconic acid, as well as mono- or dialkyl anhydrides, salts and esters thereof; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; yaz Lnn / zznz / E / YiAi olefinsulfonic acids such as vinylsulfonic acid, allyl sulfonic acid and metalyl sulfonic acid, as well as their salts; vinylsilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylα(βmethoxy-ethoxy)silane, and γ-methacryloxypropylmethoxysilane; alkylvinyl ethers; vinyl ketones; N-vinylpyrrolidone; vinyl chloride; and vinylidene chloride. EVOH can be modified through urethane, acetalization, cyanoethylation, oxyalkylation, or similar processes. Modified EVOH used as a purging agent exhibits improved compatibility with a resin being purged, such as urethane, acetal, or acrylonitrile resin, thus enabling more efficient purging. Two or more types of EVOH can be used in combination, differing from each other in ethylene unit content, degree of saponification, copolymer components, or the presence or absence of modification. EVOH can be obtained by a known method such as bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization. The method used in one instance is bulk polymerization or solution polymerization, which allows polymerization to proceed in the absence of a solvent or in a solution such as an alcohol. The solvent used in a solution polymerization method is not limited to specific solvents and is, for example, an alcohol, preferably a lower alcohol such as methanol, ethanol, or propanol. The amount of solvent to be used in a polymerization reaction solution can be selected considering the average polymerization viscosity of the intended EVOH and the solvent's chain transfer properties. The mass ratio of solvent to all monomers in the reaction solution (solvent / monomers) is, for example, 0.01 to 10 and preferably 0.05 to 3. Examples of a catalyst to be used in the polymerization described above include: azo initiators such as 2,2-azobisisobutyronitrile, 2,2-azobis-(2,4-dimethylvalveronitrile), 2,2-azobis-(4-methoxy-2,4-dimethylvalveronitrile), and 2,2-azobis-(2-cyclopropylpropionitrile); and organic peroxide initiators such as isobutyryl peroxide, cumyl peroxyneodecanoate, diisopropyl peroxycarbonate, di-n-propyl peroxydicarbonate, t-butyl peroxyneodecanoate, lauroyl peroxide, benzoyl peroxide, and t-butyl hydroperoxide. The polymerization temperature is preferably 20°C to 90°C and more preferably 40°C to 70°C. The polymerization time is preferably 2 to 15 hours and more preferably 3 to 11 hours. The polymerization rate is preferably 10% to 90% and more preferably 30% to 80% with respect to the amount of vinyl ester loaded. The resin content in the solution after polymerization is preferably 5% to 85% and more preferably 20% to 70%. yaz Lnn / zznz / E / YiAi In the polymerization described above, after allowing the polymerization to proceed for a predetermined time or after achieving a predetermined polymerization rate, a polymerization inhibitor is added, if necessary, and the unreacted ethylene gas is separated by distillation and the unreacted vinyl ester is removed to obtain EVOH. Subsequently, an alkaline catalyst is added to the copolymer solution to saponify the copolymer. Saponification can be carried out, for example, either by a continuous or batch method. Examples of alkaline catalysts that can be added include sodium hydroxide, potassium hydroxide, and alkali metal alcoholates. EVOH, after undergoing the saponification reaction, contains the alkaline catalyst, byproduct salts such as sodium acetate and potassium acetate, and other impurities. Therefore, it is preferable to remove these by neutralization or washing, if necessary. When EVOH is washed with water (e.g., ion-exchange water) substantially free of predetermined ions (e.g., metal ions and chloride ions) after the saponification reaction, some of the byproduct salts, such as sodium acetate and potassium acetate, may remain instead of being completely removed. EVOH may contain a thermoplastic resin other than EVOH, a metal salt other than the basic compound (C), an acid, a boron compound, a plasticizer, a filler, an antiblocking agent, a lubricant, a stabilizer, a surfactant, a coloring material, a UV absorber, an anti-static agent, a desiccant, a crosslinking agent, a reinforcing material such as various types of fiber, and other components. From the standpoint of improving thermal stability, the metal salt other than the base compound (C) is preferably an alkali metal salt, and more preferably an alkali ferrous metal salt. When EVOH contains a metal salt, the lower limit of the metal salt content is, for example, 1 ppm or more, more preferably 5 ppm or more, even more preferably 10 ppm or more, and most preferably 20 ppm or more, in terms of metal atoms contained in the metal salt relative to EVOH. When EVOH contains a metal salt, the upper limit of the metal salt content is, for example, 10,000 ppm or less, more preferably 5,000 ppm or less, even more preferably 1,000 ppm or less, and most preferably 500 ppm or less, in terms of metal atoms contained in the metal salt relative to EVOH. When the metal salt content is within the range described above, the thermal stability of EVOH during purging is improved.The acid described above is preferably a carboxylic acid compound, a phosphoric acid compound, or similar, from the standpoint of its ability to improve thermal stability during EVOH melt molding. When EVOH contains a carboxylic acid compound, the carboxylic acid content (i.e., the carboxylic acid content in the resin composition containing the EVOH) is preferably 1 ppm or more, more preferably 10 ppm or more, and even more preferably 50 ppm or more. Alternatively, the carboxylic acid compound content is preferably 10,000 ppm or less, more preferably 1,000 ppm or less, and even more preferably 500 ppm or less.When EVOH contains a phosphoric acid compound, the phosphoric acid content (i.e., the content of the phosphoric acid compound in terms of a phosphate group in the resin composition containing the EVOH) is preferably 1 ppm or more, more preferably 10 ppm or more, and even more preferably 30 ppm or more. Alternatively, the phosphoric acid compound content is preferably 10,000 ppm or less, more preferably 1,000 ppm or less, and even more preferably 300 ppm or less. When the content of the carboxylic acid compound or the phosphoric acid compound is within the range described above, the EVOH exhibits improved thermal stability during purging. When EVOH contains the boron compound described above, the boron compound content (i.e., the boron compound content in terms of boron in the resin composition containing the EVOH) is preferably 1 ppm or more, more preferably 10 ppm or more, and even more preferably 50 ppm or more. Alternatively, the boron compound content is preferably 2000 ppm or less, more preferably 1000 ppm or less, and even more preferably 500 ppm or less. When the boron compound content is within the range described above, EVOH tends to exhibit improved thermal stability during purging. The method for incorporating the carboxylic acid compound, phosphoric acid compound, or boron compound described above into the EVOH-containing resin composition is not limited to any particular method. For example, the compound can be added and kneaded into the EVOH-containing composition during pelleting. Other examples of the method include: adding the compound in dry powder form; adding the compound as a paste impregnated with a predetermined solvent; adding the compound as a suspension in a predetermined liquid; adding the compound as a solution obtained by dissolving the compound in a predetermined solvent; and immersing the compound in a predetermined solution.Of these methods, a method for adding the compound in the form of a solution obtained by dissolving the compound in a predetermined solvent and a method for immersing the compound in a predetermined solution are preferred from the standpoint of their ability to uniformly disperse the compound in the EVOH. The predetermined solvent is not limited to any particular solvents and is preferably water from the standpoint of the solubility of the compound to be added, ease of handling, safety of the working environment, and similar factors. (Polyvinyl alcohol) Polyvinyl alcohol is a resin obtained through the saponification of a polymer composed of vinyl ester monomers. Examples of vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, 2,2,4,4-tetramethylvinyl valerate, vinyl benzoate, vinyl pivalate, and vinyl versatate. Of these, vinyl acetate, vinyl propionate, vinyl pivalate, and vinyl versatate are preferably used either alone or in a mixture. The degree of saponification of polyvinyl alcohol is not limited to particular values, and is preferably 80% molar or more, more preferably 90% molar or more, and even more preferably 95% molar or more. (Polyamide) A polyamide is a polymer with amide bonds in its main chain. Examples of polyamide include polycaproamide (nylon 6), pol¡-ω-am¡noheptanoic acid (nylon 7), polyω-aminononanoic acid (nylon 9), polyundecamide (nylon 11), polylauryl lactam (nylon 12), polyethylenediamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyoctamethylen adipamide (nylon 86), polydecamethylen adipamide (nylon 106), a caprolactam / lauryl lactam copolymer (nylon 6 / 12), a caprolactam / ω-aminononanoic acid copolymer (nylon 6 / 9), un caprolactam / hexamethylenediamine adipate copolymer (nylon 6 / 66), lauryl lactam / hexamethylenediamine adipate copolymer (nylon 12 / 66), ethylethylenediamine adipate / hexamethylenediamine adipate copolymer (nylon 26 / 66)a copolymer of caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate (nylon 6 / 66 / 610), a copolymer of ethylenediammonium adipate / hexamethylenediammonium adipate / hexamethylenediammonium sebacate (nylon 26 / 66 / 610), polyhexamethylene isophthalamide (nylon 61), polyhexamethylene terephthalamide (nylon 6T) cyclohexylamide, polynonamethylene cyclohexylamide and modified polyamides obtained by modifying these Polyamides with an aromatic amine such as methylenebenzylamine or metaxylenediamine. Other examples of polyamide include meta-xylylenediammonium adipate. A polyamide is obtained by melt polymerization, interfacial polymerization, solution polymerization, bulk polymerization, solid-state polymerization, or a combination thereof. (Polyacrylate) A polyacrylate can be prepared by polymerizing acrylate monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, pentyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, α-chloroethyl acrylate, cyclohexyl acrylate, phenyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, methoxypropyl acrylate or ethoxypropyl acrylate, and then by hydrolyzing the resulting polymerization product. A polyacrylate can also be obtained by polymerizing acrylonitrile and hydrolyzing the resulting polymerization product. Examples of salts used as components of polyacrylate include alkali metal salts such as sodium, potassium, and lithium; alkali metal salts such as calcium, magnesium, and barium; and ammonium salts such as quaternary ammonium and quaternary alkylammonium compounds. Sodium salts, being the most commonly used, are preferred. (Polyethylene Glycol) A polyethylene glycol is produced through polymerization by addition of ethylene oxide with a compound having two or more active hydrogens, such as ethylene glycol or diethylene glycol. For the addition of ethylene oxide, an alkali metal compound can be used as a catalyst. Examples of alkali metal compounds include alkali metal hydroxides (e.g., lithium, sodium, and potassium) and alkali metal alcoholates (e.g., sodium methylate and potassium methylate). Of these, sodium hydroxide and potassium hydroxide are preferred from a reactivity standpoint. One type of alkali metal compound can be used, or two or more types can be used in combination. (Polyacrylamide) As polyacrylamide, a homopolymer of an acrylamide or a copolymer of an acrylamide with one or more of the other copolymerizable monomers, each with amide linkages, is used. The method for producing polyacrylamide is not limited to particular methods, and polyacrylamide is produced by a method such as: (i) polymerizing an acrylamide in methanol using 2,2'-azobisisobutyronitrile as an initiator; (ii) irradiating an acrylamide with light in ethanol; (iii) causing the redox polymerization of an acrylamide in an aqueous solution; or (iv) irradiating a solid-state acrylamide with gamma rays. Examples of other monomer(s) that can be copolymerized with an acrylamide include acrylic acid, methacrylic acid, styrenesulfonic acid, ethylenesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, dimethylaminoethyl methacrylate ester, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, diallyldimethylammonium chloride, and salts 7Q7 Lnn / Zznz / E / YIAI quaternary compounds thereof, and Cl to C24 alkyl esters of acrylic acids such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate. (Water (B)) Water (B) dissolves the basic compound (C) described below to prepare an aqueous solution having a desired pH and also diffuses the EVOH described above widely through a molding machine, thereby promoting the discharge of a purging resin present in the molding machine. Examples of water (B) as one of the components of the resin composition of the present invention include pure water, ion-exchange water, distilled water, and tap water, as well as combinations thereof. Ion-exchange water is preferred in order to avoid unintentional contamination with salts. In the resin composition of the present invention, the mass ratio (A) / (B) of the hydrophilic resin (A) to water (B) is 66 / 34 to 90 / 10, preferably 70 / 30 to 90 / 10, more preferably 75 / 25 to 90 / 10, and even more preferably 80 / 20 to 88 / 12. When the mass ratio of the hydrophilic resin (A) to water (B) is within the range described above, the uneven distribution of water on the surface of the purging agent composed of the resin composition of the present invention can be eliminated. This is preferred in terms of safety because it can prevent the purging agent from adhering to a hopper when introducing the purging agent and can also prevent the aqueous solution containing the base compound (C) from dispersing from the purging agent. The hydrophilic resin (A) in the resin composition of the present invention has a high affinity for water and binds to water to an appropriate extent through hydrogen bonds.Therefore, the resin composition can release the required liquid component for purging from the molding machine during purging, and furthermore, the resin composition can maintain sufficient viscosity to discharge the resin being purged from the molding machine. Additionally, excess liquid component is not retained in the molding machine during purging, thus reducing defective feeds. In the resin composition according to a first embodiment of the present invention, water (B) is one of the essential components for enabling the resin composition to perform a purging function for a resin being purged. In contrast, in the resin composition according to a second embodiment of the present invention, which will be described below, water (B) may be one of the optional components. That is, although water (B) needs to be contained as a constituent component of the resin composition passing through a molding machine when purging a resin, the purging agent, before being supplied to the molding machine, need not necessarily contain water (B). 7Q7 ίηη / ZZΖηZ / E / YILI advanced. For example, when the purging agent is supplied to a molding machine, water (B) can be supplied to the molding machine separately from the purging agent and mixed with the purging agent components in the molding machine to form the resin composition of the present invention. In the resin composition of the present invention, water (B) and hydrophilic resin (A) can be contained in the form of a water-containing hydrophilic resin obtained by mixing them together. The method for preparing hydrophilic resin containing water is not limited to specific methods, and examples of the method include: spraying water (B) onto the hydrophilic resin (A); immersing the hydrophilic resin (A) in water (B); bringing the hydrophilic resin (A) into contact with water vapor, which is a form of water (B); and extruding the hydrophilic resin (A) together with the water (B). More specific examples of the method include: autoclaving the hydrophilic resin (A) in the presence of water (B); and introducing the hydrophilic resin (A) into an extruder and then subjecting the hydrophilic resin (A) to moisture extrusion while adding water (B) at some point during the extrusion process. (Basic compound (O) The basic compound (C) forms an aqueous solution when mixed with the water described above (B), and plays a role in promoting the discharge of a resin to be purged present in a molding machine by making the conditions inside the molding machine alkaline (preferably strongly alkaline). Examples of the basic compound (C) include alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, alkali metal hydroxides, ammonia, and primary to tertiary amines, as well as their combinations. When water (B) and hydrophilic resin (A) together form a hydrophilic resin containing water, examples of the basic compound (C) include alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, alkali metal hydroxides, ammonia, and primary to tertiary amines, as well as combinations thereof. On the other hand, when water (B) and basic compound (C) together form an alkaline aqueous solution, examples of the basic compound (C) include alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, ammonia, and primary to tertiary amines, as well as combinations thereof. Examples of alkali metal carbonates include sodium carbonate, potassium carbonate, and lithium carbonate, as well as combinations thereof. Examples of alkali metal bicarbonates include sodium bicarbonate and potassium bicarbonate, as well as combinations thereof. Examples of alkali metal phosphates include trisodium phosphate and hydrogen phosphate. 7Q7 Lnn / Zznz / E / YIAI disodium, monosodium dihydrogen phosphate, tripotassium phosphate, dipotassium hydrogen phosphate, monopotassium dihydrogen phosphate, trilithium phosphate, dilithium hydrogen phosphate, and monolithium dihydrogen phosphate, as well as combinations thereof. Examples of alkali metal acetates include sodium acetate, potassium acetate, and lithium acetate, as well as combinations thereof. Examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, and lithium hydroxide, as well as combinations thereof. Sodium carbonate and potassium carbonate are preferred due to their sufficient purging capacity and ability to ensure the safety of operators using the purging agent. The content of the basic compound (C) is 0.25 parts by mass or more, preferably 0.3 parts by mass or more, and more preferably 0.4 parts by mass or more, relative to 100 parts by mass of the hydrophilic resin (A). Alternatively, the content of the basic compound (C) is 7 parts by mass or less, preferably 6 parts by mass or less, and more preferably 4 parts by mass or less, relative to 100 parts by mass of the hydrophilic resin (A). When the content of the basic compound (C) is less than 0.25 parts by mass, an aqueous solution composed of the basic compound (C) and water (B) has a near-neutral pH, thus reducing the efficiency of discharging a resin that is to be purged from the molding machine. When the content of the basic compound (C) is greater than 7 parts by mass, the alkaline aqueous solution becomes saturated, so salt precipitation is likely to occur during storage of the purge resin. When water (B) and the basic compound (C) together form an alkaline aqueous solution, the pH of the alkaline aqueous solution and / or the resin composition of the present invention is preferably 8 to 14 and more preferably 10 to 13. When the pH is less than 8, the resulting resin composition tends to exhibit a decrease in the discharge efficiency of a resin to be purged in a molding machine. (Thermoplastic resin (DD) The resin composition of the present invention may further contain a thermoplastic resin (D), in addition to the hydrophilic resin described above (A), water (B), and the base compound (C). The thermoplastic resin (D) is a thermoplastic resin that is different from the hydrophilic resin (A), and is added to the resin composition of the present invention in order to, for example, improve the compatibility of the resin composition of the present invention with a purging resin present in a molding machine and improve operator safety. Examples of thermoplastic resin (D) include EVOH resins, vinyl alcohol resins (such as PVA resins) other than EVOH resins, PA resins, polyolefin resins (linear low-density polyethylenes, low-density polyethylenes, medium-density polyethylenes, high-density polyethylenes, ethylene-vinyl acetate copolymers, ionomers, ethylene-propylene copolymers, ethylene-acrylic ester copolymers, polypropylenes, propylene-aolefin copolymers (an α-olefin having 4 to 20 carbon atoms), polybutenes, polypentenes, and the like), modified polyolefin resins obtained by grafting polyolefin resins with an unsaturated carboxylic acid, polyester resins, polyvinyl chloride resins, resins of thermoplastic polyurethane, polyvinylidene chloride, acrylic resins, polystyrene resins, vinyl ester resins, polyester elastomers, polyurethane elastomers,chlorinated polyethylenes, chlorinated polypropylenes, and aromatic or aliphatic polyketides, as well as combinations thereof. The content of the thermoplastic resin (D) is preferably 1 part by mass or more, more preferably 50 parts by mass or more, and even more preferably 100 parts by mass or more, relative to 100 parts by mass of the hydrophilic resin (A). The content of the thermoplastic resin (D) is preferably 10,000 parts by mass or less relative to 100 parts by mass of the hydrophilic resin (A). When the content of the thermoplastic resin (D) is within the range described above, the compatibility of the resin composition of the present invention with a resin to be purged from a molding machine is improved, thereby further enhancing the efficiency of the purging process and improving operator safety. A suitable scale for the upper limit of the thermoplastic resin (D) content may vary depending on the viscosity of the thermoplastic resin (D) to be used. When the thermoplastic resin (D) has a low viscosity (MFR at 190°C equal to or greater than 1 g / 10 minutes), the upper limit is preferably 990 parts by mass or less, more preferably 800 parts by mass or less, and even more preferably 600 parts by mass or less, with respect to 100 parts by mass of the hydrophilic resin (A). On the other hand, when the thermoplastic resin (D) has high viscosity (MFR at 190°C is less than 1 g / 10 minutes), the upper limit is preferably 10,000 parts by mass or less, more preferably 5,000 parts by mass or less, even more preferably 2,000 parts by mass or less, and particularly preferably 1,500 parts by mass or less, with respect to 100 parts by mass of the hydrophilic resin (A). When the upper limit is within the range described above, the effect of the present invention can be achieved more effectively. However, the range described above may vary depending on the molding machine to be used. (Other additives) The resin composition of the present invention may further contain one or more additives, provided that the effects of the present invention are not affected. Examples of other additives include abrasives, fillers, heat stabilizers, and processing aids. 7Q7 Lnn / Zznz / E / YIAI antiblocking agents, antistatic agents, coupling agents, antioxidants, lubricants, foaming agents, surfactants, and plasticizers, as well as combinations thereof. In particular, an abrasive is used to remove a resin from the molding machine by means of physical polishing, and examples include compounds of inorganic compounds such as alumina, zirconium, silica, titanium dioxide, and calcium carbonate. In the resin composition of the present invention, the content of the additive(s) is not limited to particular values ​​and those skilled in the art may set them accordingly within a range in which the purging efficiency achieved by the combination of the hydrophilic resin (A), water (B) and the basic compound (C) described above is not affected. (Purge agent) The purging agent according to the first embodiment of the present invention comprises the resin composition described above, primarily a resin composition containing a hydrophilic resin (A), water (B), and a base compound (C), and where necessary, any of the optional components such as a thermoplastic resin (D) that is different from the hydrophilic resin (A), and other additives. In this specification, the purging agent comprised of the resin composition described above is referred to as a first purging agent. The purging agent according to the second embodiment of the present invention comprises the resin composition described above, excluding water (B), primarily a resin composition containing a hydrophilic resin (A) and a base compound (C), and, when necessary, any of the optional components such as a thermoplastic resin (D) other than the hydrophilic resin (A), and other additives. In this specification, the purging agent comprising the resin composition described above, excluding water (B), is referred to as a second purging agent. The types and contents of the hydrophilic resin (A), the base compound (C), the thermoplastic resin (D) that is different from the hydrophilic resin (A), and the other additives in the second purging agent of the present invention can be selected similarly to the types and contents of the contents in the first purging agent. Also, the ethylene unit content and the degree of saponification of the hydrophilic resin (A) in the second purging agent of the present invention can be established similarly to that of the hydrophilic resin (A) contained in the first purging agent. The first purging agent of the present invention is excellent in terms of safety because an operator does not have to adjust the contents of the purging agent components when introducing the purging agent into a molding machine. On the other hand, the second purging agent of the present invention does not contain water (B) in advance, and thus the mass and volume of the purging agent as a whole can be made smaller than those of the first purging agent. This can improve the efficiency of transporting and storing the purging agent. In the present invention, the first purging agent can be used by introducing it as is into a molding machine in which there is a resin to be purged, for example, through a hopper. On the other hand, the second purging agent of the present invention can be used by adding a predetermined amount of water (B) to it before use to prepare a resin composition of the present invention, and then introducing the composition thus obtained into a molding machine in which a resin to be purged is present, for example, through a hopper. Alternatively, the second purging agent of the present invention can also be used by introducing the purging agent in a state that does not contain water (B) into a molding machine in which a resin to be purged is present, for example, through a hopper, then adding water (B) to the purging agent from a separately provided part of the molding machine (for example, an orifice provided to pass through a cylinder) and kneading them in the cylinder, thereby preparing the resin composition of the present invention. The molding machines to which the first and second purging agents of the present invention are applicable refer to various types of commonly used molding machines and passages through which resins flow in molding machines. The molding machines used in the present invention are not limited to particular types of molding machine, and examples include extruders (including single-screw and twin-screw extruders, for example), injection molding machines, single-layer film molding machines, single-layer blow molding machines, sheet co-extrusion molding machines, film co-extrusion molding machines, multi-layer blow molding machines, and co-injection molding machines, as well as piping, feed blocks, dies, and the like of each molding machine. (Method for purging the molding machine where the resin to be purged is present) In the purging method of the present invention, for example, a resin composition containing the above-described hydrophilic resin (A), water (B), and the base compound (C), and where necessary, the thermoplastic resin (D) that is different from the hydrophilic resin (A) and / or one or more additives as optional component(s), is supplied to a molding machine, and the resin composition is discharged together with a resin to be purged. In this specification, the purging method performed using the resin composition as described above is referred to as a first purging method. In the first purging method of the present invention, the resin composition can be supplied to a molding machine, for example, by separately supplying the hydrophilic resin (A), water (B), and base compound (C), and, when necessary, the thermoplastic resin (D), which is different from the hydrophilic resin (A), and / or one or more additives as an optional component(s), to the molding machine through a hopper and / or another part (for example, an orifice provided for passing through a cylinder) of the molding machine. Preferably, the resin composition is supplied to the molding machine in the form of the first purging agent or the second purging agent described above of the present invention. The following description relates to an embodiment in which a molding machine is an extruder. When the resin composition is supplied to an extruder in the form of the first purging agent of the present invention, the first purging agent of the present invention is introduced into the extruder as is, for example, through an extruder hopper, and the first purging agent is then supplied to a cylinder by rotating a screw provided in the cylinder. When the resin composition is supplied to an extruder in the form of the second purging agent of the present invention, a predetermined amount of water (B) is added to the second purging agent before use. The resulting composition is then fed into the extruder, for example, through an extruder hopper, and the second purging agent is supplied to a barrel by rotating a screw provided in the barrel. In this case, to prevent corrosion of metal parts such as the hopper, the base compound (C) as a component of the second purging agent is preferably selected from the options mentioned above, excluding alkali metal hydroxides. Alternatively, the second purging agent of the present invention is supplied by introducing the second purging agent in a state of not containing water (B) into an extruder, for example, through an extruder hopper, by adding water (B) to the purging agent from a separately provided part in the molding machine (for example, an orifice provided to pass through a cylinder), and by kneading them together by turning a screw in the cylinder. When the resin composition is fed into the molding machine, the purge temperature (i.e., the temperature of the molding machine's melting region) can be adjusted accordingly, depending on the specifications of the molding machine being used and the viscosity of the thermoplastic resin (D). However, a suitable purge temperature range can vary, particularly depending on the viscosity of the thermoplastic resin (D). When the thermoplastic resin (D) has a low viscosity (MFR at 190°C is equal to or greater than 1 g / 10 minutes), the temperature is preferably set between 105°C and 170°C, and more preferably between 110°C and 160°C. When the temperature is below 105 °C, / 07 Lnn / 77n7 / E / YIAI the resin composition in the molding machine may not melt sufficiently, so it may be difficult to efficiently discharge the resin to be purged.When the temperature is above 170°C, the viscosity of the resin may decrease, and this can result in a decrease in purging efficiency. On the other hand, when the thermoplastic resin (D) has a high viscosity (MFR at 190°C is less than 1 g / 10 minutes), the temperature is preferably set to 150°C to 230°C, more preferably 170°C to 210°C, and even more preferably 180°C to 200°C. When the temperature is below 150°C, the resin composition in the molding machine has a high viscosity, which can make efficient discharge of the resin to be purged difficult. When the temperature is above 230°C, the resin viscosity may decrease, and this can result in a significant decrease in purging efficiency. The quantity of resin composition supplied to the molding machine is, for example, preferably not less than 1 and not more than 1000 times, and more preferably not less than 2 and not more than 100 times, the volume of residual resin to be purged from the molding machine (for example, this volume is obtained by subtracting the screw capacity from the barrel capacity when the molding machine is an extruder). When the quantity of resin composition supplied is less than 1 time the volume of residual resin to be purged from the molding machine, there is a risk that the resin to be purged will remain in the molding machine.When the amount of resin composition supplied is more than 1000 times the volume of residual resin to be purged in the molding machine, an excess amount of resin composition is supplied despite the fact that the purging effect is already sufficiently shown in the molding machine, and this can result in a decrease in the utilization efficiency of the purging agent. Alternatively, instead of the first purging method described above, another purging method of the present invention can be carried out such that an alkaline aqueous solution containing water (B) and the base compound (C) is supplied to a molding machine, and the alkaline aqueous solution is discharged together with a resin to be purged. In this specification, the purging method carried out using the alkaline aqueous solution as described above is referred to as a second purging method. The water (B) used in the second purging method of the present invention is the same as that used in the resin composition of the present invention. Examples of the basic compound (C) used in the second purging method of the present invention include alkali metals such as lithium, sodium, and potassium. Examples of a salt that can be used as the basic compound (C) include carbonates, bicarbonates, and phosphates. Examples of the basic compound (C) include sodium carbonate, potassium carbonate, 7Q7 Lnn / Zznz / E / YIAI lithium carbonate, sodium bicarbonate, potassium bicarbonate, trisodium phosphate, disodium biphosphate, monosodium dihydrogen phosphate, tripotassium phosphate, dipotassium biphosphate, monopotassium dihydrogen phosphate, trilithium phosphate, dilithium biphosphate, monolithium dihydrogen phosphate, sodium acetate, potassium acetate, lithium acetate, and combinations thereof. From the standpoint of ensuring operator safety, sodium carbonate and potassium carbonate are preferred. The pH of the alkaline aqueous solution supplied to the molding machine is preferably 8 to 14 and more preferably 10 to 13. When the pH is less than 8, the resulting alkaline aqueous solution tends to exhibit a decrease in the discharge efficiency of a resin to be purged in a molding machine. In the second purging method of the present invention, the alkaline aqueous solution can be supplied to a molding machine, for example, by premixing water (B) and the basic compound (C) to prepare an alkaline aqueous solution and supplying the resulting alkaline aqueous solution to the molding machine through a hopper and / or another part (for example, an orifice provided to pass through a cylinder) of the molding machine. However, an alkaline aqueous solution containing a hydroxide such as the basic compound (C) can cause undesirable corrosion when it adheres to metal parts such as the hopper.Therefore, it is preferable to introduce the alkaline aqueous solution into the cylinder through a tube made of a chemical-resistant material (e.g., silicone rubber, Teflon®, or similar) that utilizes the fluidity of the alkaline aqueous solution, thus reducing the possibility of the solution coming into contact with metal parts, excluding the interior of the molding machine. Alternatively, the alkaline aqueous solution can be supplied separately by introducing water (B) and the base compound (C) through the hopper and / or another part (e.g., the orifice provided for passage through the cylinder) of the molding machine and preparing the alkaline aqueous solution inside the molding machine. It is also preferable to supply the hydrophilic resin (A) and the different thermoplastic resin (D) together with the alkaline aqueous solution. When supplying the alkaline aqueous solution to the molding machine, the temperature inside the molding machine (i.e., the temperature of the molding machine's melting region) is preferably set between 105°C and 230°C, and more preferably between 110°C and 210°C. When the temperature is below 105°C, efficient purging of the resin may be difficult. When the temperature is above 230°C, some of the liquid component may vaporize, so the alkaline aqueous solution may not act efficiently on the resin being purged. When the alkaline aqueous solution is supplied according to the second purging method of the present invention, the molding machine can be washed thereafter using 7Q7 Lnn / Zznz / E / YIAI an appropriate amount of water (e.g., pure water, ion exchange water, distilled water, tap water, or a combination thereof) in order to prevent corrosion from occurring in the molding machine. The present invention allows for the purging of various types of resins. The resin to be purged, for example, is a thermoplastic resin or a mixture containing thermoplastic resin. Examples of thermoplastic resin as the resin to be purged include EVOH, vinyl alcohol resins (such as PVA resins) other than EVOH resins, PA resins, polyolefin resins (linear low-density polyethylenes, low-density polyethylenes, medium-density polyethylenes, high-density polyethylenes, ethylene-vinyl acetate copolymers, ionomers, ethylene-propylene copolymers, ethylene-acrylic ester copolymers, polypropylenes, propylene-α-olefin copolymers (α-olefin having 4 to 20 carbon atoms), polybutenes, polypentenes, and the like), modified polyolefin resins obtained by grafting polyolefin resins with an unsaturated carboxylic acid, polyester resins,polyvinyl chloride resins, thermoplastic polyurethane resins, polyvinylidene chloride, acrylic resins, polystyrene resins, vinyl ester resins, polyester elastomers, polyurethane elastomers, chlorinated polyethylenes, chlorinated polypropylenes, and aromatic or aliphatic polyketones, as well as combinations thereof. The resin to be purged, for which the present invention is particularly desirable, is a collected waste. The waste as used herein may be: (1) an out-of-specification product or a cut produced during the manufacturing process of a multi-layer structure; or (2) packaging material collected after use in the market. Each layer of the multi-layer structure may be formed from any of the resins named above as examples of the resin to be purged. Specifically, for example, there are often cases where waste generated during the production of a multi-layer structure is collected and melt-molded in an extruder for recycling as at least one layer of a newly produced multi-layer structure. In such a recycling operation, the resin composition used to form the multi-layer structure can be severely degraded by the thermal history during melting and kneading in the extruder. Furthermore, if the resin composition used to form the multi-layer structure contains a resin that is reactive during melting and kneading, the resin composition can be severely degraded.The purging agent of the present invention can also be used effectively for resin to be purged in a state where it adheres more firmly to a flow passage as a result of such severe deterioration. 7Q7 Lnn / Zznz / E / YIAI EXAMPLES The present invention will be described in detail with reference to the examples. However, it should be noted that the present invention is not limited to these examples in any way. The components used in the examples and comparative examples were the following. (Hydrophilic resin (A)) • A1: EVOH (EVAL F101B manufactured by Kuraray Co., Ltd., ethylene unit content: 32 mol%, saponification grade: 99 mol% or more) • A2: EVOH (EVAL L171B manufactured by Kuraray Co., Ltd., ethylene unit content: 27 mol%, saponification grade: 99 mol% or more) • A3: EVOH (EVAL E105B manufactured by Kuraray Co., Ltd., ethylene unit content: 44 mol%, saponification grade: 99 mol% or more) • A4: Polyvinyl alcohol (POVAL 29-99 manufactured by Kuraray Co., Ltd., saponification grade: 99 mol% or more) • A5: Polyamide (UBE NYLON 1024Bmanufactured by Ube Industries, Ltd.) (nylon 6) • A6: EVOH (EVAL G176B manufactured by Kuraray Co., Ltd., the content of ethylene units: 48 mol%, the degree of saponification: 99 mol% or more) (Thermoplastic resin (D) yaz Lnn / zznz / E / YiAi • di: Low-density polyethylene (LC-600A manufactured by Japan Polyethylene Corporation, MFR: 7 g / 10 minutes) • d2: Low-density polyethylene (UJ790 manufactured by Japan Polyethylene Corporation, MFR: 50 g / 10 minutes) • d3: High-density polyethylene (HB111R manufactured by Japan Polyethylene Corporation) Corporation, MFR: 0.03 g / 10 minutes) EXAMPLE OF FORMULATION 1 Production of the Resin Composition (The) 100 parts by mass of EVOH (Al) were autoclaved at 135°C for 1 hour, and an aqueous EVOH resin containing 32 parts by mass of ion-exchange water was immersed in an 11% by mass aqueous sodium carbonate solution containing 260 parts by mass of ion-exchange water and 1.1 parts by mass of sodium carbonate at room temperature for 3 hours. The excess aqueous sodium carbonate solution was then removed using a centrifuge. As a result, an aqueous EVOH resin containing 100 parts by mass of EVOH (Al), 32 parts by mass of ion-exchange water, and 3.2 parts by mass of sodium carbonate was obtained. 264 parts by mass of low-density polyethylene (di) were mixed with the resulting aqueous EVOH resin by dry mixing. This yielded the resin composition (El).The pH of the resin composition obtained in this way (El) was measured using a pH meter (HI-98125 manufactured by Hannah Instruments Japan). The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 2 Production of Resin Composition (E2) A resin composition (E2) was obtained in the same way as in Formulation Example 1, except that EVOH (A2) was used instead of EVOH (Al). The results obtained are shown in Table 1: EXAMPLE OF FORMULATION 3 Production of Resin Composition (E3) A resin composition (E3) was obtained in the same way as in Formulation Example 1, except that EVOH (A3) was used instead of EVOH (Al). The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 4 Production of the Resin Composition (E41 100 parts by mass of polyvinyl alcohol (A4) were immersed in a 10% by mass aqueous sodium carbonate solution containing 180 parts by mass of ion exchange water and 18 parts by mass of sodium carbonate at 60°C for 8 hours. The excess aqueous sodium carbonate solution was then removed using a centrifuge. As a result, an aqueous polyvinyl alcohol resin containing 100 parts by mass of polyvinyl alcohol (A4), 32 parts by mass of ion exchange water, and 3.2 parts by mass of sodium carbonate was obtained. 264 parts by mass of low-density polyethylene (LDPE) were mixed with the resulting aqueous polyvinyl alcohol resin by dry mixing. This yielded resin composition (E4). The pH of the resin composition thus obtained (E4) was measured using a pH meter (HI-9812-5 manufactured by Hannah Instruments Japan).The results obtained are shown in Table 1. / 07 Lnn / 77n7 / E / YIAI EXAMPLE OF FORMULATION 5 Production of Resin Composition (E5) 100 parts by mass of polyamide (A5) were autoclaved at 135°C for 3 hours to obtain an aqueous polyamide resin containing 30 parts by mass of ion-exchange water. The polyamide resin thus obtained was immersed in an 11% by mass aqueous sodium carbonate solution containing 235 parts by mass of ion-exchange water and 25 parts by mass of sodium carbonate at room temperature for 3 hours. The excess aqueous sodium carbonate solution was then removed using a centrifuge. As a result, an aqueous polyamide resin containing 100 parts by mass of polyamide (A5), 32 parts by mass of ion-exchange water, and 3.2 parts by mass of sodium carbonate was obtained. 264 parts by mass of low-density polyethylene (LDPE) were blended with the aqueous polyamide resin obtained by dry blending.Thus, the resin composition (E5) was obtained. The pH of the resin composition obtained in this way (E5) was measured using a pH meter (HI-9812-5 manufactured by Hannah Instruments Japan). The results obtained are shown in Table 1. EXAMPLES OF FORMULATION 6 TO 9 Production of Resin Compositions (E6) to (E9) The resin compositions (E6) to (E9) were obtained in the same way as in Formulation Example 1, except that the mixed quantities of ion exchange water, sodium carbonate and low density polyethylene (di) were established as shown in Table 1. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 10 Production of Resin Composition (E1O) A resin composition (E10) was obtained in the same way as in Formulation Example 1, except that 2.5 parts by mass of trisodium phosphate were used instead of sodium carbonate. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 11 Production of Resin Composition (Eli) / 07 ίΠη / 77η7 / Ε / ΥΙΛΙ A resin composition (Eli) was obtained in the same way as in Formulation Example 1, except that 1.3 parts by mass of sodium hydroxide were used instead of sodium carbonate. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 12 Production of Resin Composition (E12) A resin composition (E12) was obtained in the same way as in Formulation Example 1, except that 3.2 parts by mass of potassium carbonate were used instead of sodium carbonate. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 13 Production of Resin Composition (E13) An aqueous EVOH resin containing 100 parts by mass of EVOH (Al) and 32 parts by mass of ion exchange water was immersed in an 11% ammonia solution containing 260 parts by mass of ion exchange water and 32 parts by mass of ammonia at room temperature for 3 hours under sealed conditions. The excess aqueous ammonia solution was then removed using a centrifuge. As a result, an aqueous EVOH resin containing 100 parts by mass of EVOH (Al), 32 parts by mass of ion exchange water, and 3.2 parts by mass of ammonia was obtained. 264 parts by mass of low-density polyethylene (LDPE) were mixed with the resulting aqueous EVOH resin by dry mixing. This yielded the resin composition (E13). EXAMPLE OF FORMULATION 14 Production of the Resin Composition (E14Ί A resin composition (E14) was obtained in the same manner as in Formulation Example 1, except that the mixed quantities of ion exchange water and sodium carbonate were set as shown in Table 1 and that low-density polyethylene (LDPE) was not used. The results obtained are shown in Table 1. / 07 Lnn / zznz / E / YiAi EXAMPLE OF FORMULATION 15 Production of Resin Composition (E15) A resin composition (E15) was obtained in the same manner as in Formulation Example 1, except that: the mixed quantities of ion exchange water and sodium carbonate were established as shown in Table 1; 244.4 parts by mass of low-density polyethylene (di) were used; and an additional 12.2 parts by mass of low-density polyethylene (d2) were used. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 16 Production of Resin Composition (E16) A resin composition (E16) was obtained in the same way as in Formulation Example 1, except that 3.2 parts by mass of sodium acetate were used instead of sodium carbonate. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 17 Production of Resin Composition (E17) A resin composition (E17) was obtained by mixing 3.3 parts by mass of a 9% by mass aqueous sodium carbonate solution (pH = 12.0) and 95 parts by mass of low-density polyethylene (di) without using EVOH (Al). The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 18 Production of Resin Composition (E18) A resin composition (E18) was obtained by mixing 5.5 parts by mass of 9% ammonia water (pH = 11.0) and 94 parts by mass of low-density polyethylene (di) without using EVOH (Al). The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 19 Production of Resin Composition (Cl) A resin composition (Cl) was obtained in the same way as in Formulation Example 1, except that 0.9 parts by mass of ion exchange water and 0.2 parts by mass of sodium carbonate were used. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 20 Production of Resin Composition (C2) A resin composition (C2) was obtained in the same way as in Formulation Example 1, except that 60 parts by mass of ion exchange water and 12 parts by mass of sodium carbonate were used. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 21 Production of the Resin Composition (C3J A resin composition (C3) was obtained in the same way as in Formulation Example 1, except that 268 parts by mass of low-density polyethylene (di) were used and sodium carbonate was not used. The results obtained are shown in Table 1. EXAMPLE OF FORMULATION 22 Production of the Resin Composition (E19Ί A resin composition (E19) was obtained in the same way as in Formulation Example 12, except that 1188 parts by mass of high-density polyethylene (d3) were used. The results obtained are shown in Table 1. / 07 ίηη / 77η7 / E / YΙΛΙ TABLE 1 pH of the Resin Composition 12.0 12.0 12.0 12.0 12.0 12.0 12.0 10.5 12.4 12.9 13.3 Thermoplastic Resin (D) Contained (Partes en Masa) s ΓΜ LO (N nlO OI LD OI 'T LO OJ OI O ó o en LO OI nLO OJ nLO rxi ^r lO OI Basic Compound (C) Contained (Parts in Masa) oí en OI en OI en 01 en OI en OJ r\jo i_n en o LO LO eN en 1—1 O Q_ mou tu 2 ó u tu Z moy tu ó y re Z Na2CO3 ó y tu ó y tu Z Na2CO3 Na2CO3 Ó o_ tu I o ra EVOH(A) / Agua (B) oj LO OJ LO s lo oj LO Ol LO co 1—1 oT 00 en rn LO OJ LO Ol LO oj LO oj LO Water (B) Contenido (Partes en Masa) ΓΜ en OI en e\i en eN en OJ m OI OJ rxi O o LO eN en eN en OI en OI en Hydrophilic Resin (A) Contained (Parts in Masa) ooi—I oo iI ooi—loo τ—1 ooi—loo 1—1 ooi—looi—loo 1—1 oo 1—1 ooi—l Ethylene Container (% molar) ΓΜ en OJ 1 1 OI en OI en oj en OI en exi en e\i en O Q_ < OI < en < < LO < < < < < < < Resin Composition LU or LU en LU «^z LU s—z LO LU «^zo LU s—z LLJ 00 LU s—z 5? LLJ,θ' LU 1—I LU Formulation Example 1 Formulation Example 2 Formulation Example 3 Formulation Example 4 Formulation Example 5 Formulation Example 6 Formulation Example 7 Formulation Example 8 Formulation Example 9 Formulation Example 10 Formulation Example ll, / 07 ίηη / ζζηζ / Ε / γίΛΐ Φ O o O exi O o C0 Φ rxj i—1 i—1 exj 1—1 rxj 1—1 στ exj 1—1 i—l exj 1—1 nj i—l LO rxj i—l rxi ϕ 12. Φ Φ Φ 00 LD LO 1 LD LD LD Φ exj 244.4 (N exj exi rxj 1----1 OJ rxi στ exi en Ln exj exi 00 en en 1—I en oo O Ó O υ X yoy X ouo £ z 2 (ü oo u φ Γ\| rxi exi 1—I exj oo in rxi χο ld in Φ LD στ in LD LD 00 oo LO (Ν CXJ oq LD CX1 στ o rxj in en en en ϓ 1—1 en o o LD Ι in m 1—1 oi—loi—looo 1—1 oi—lo 1—1 oi—l (Ν CXl exi e\i CX1 exj cxi en exi m en en en m Al Al Al Al 1 1 Al Al Al ex? en φ' un ld CO s exj m σ' LU_ LU LU? LU_ LU LU LU? e\l in LO LD pX, CO στ o 1—1 rxi Φ Φ 1-1 Φ 1-1 Φ 1-1 Φ Φ Φ 1-1 Φ 1-1 03 <13 <13 Ό CZ Ό C T3 C Ό Ό C C Ό Ό oS °-§ °-§ ° ·§ o-8 °-§ o-§ °;8 o-8 θ·8 ° ·§ CL 03 CL 03 Cl 03 CL 03 cl ru Q- Π3 Q- 03 CL 03 CL 03 Q- 03 CL 3 ED 3 t 03 E EE EE E 3 .3⁄4 YES, E .3⁄4 E .3⁄4 YESS4E E Ϊ, E Ϊ, E wo ω o ω o ω owoo ω o 113 owoo ω o LL LL. / 07 ίηη / ζζηζ / Ε / γίΛΐ EXAMPLE 1 Purging the resin to be purged EVOH (Al) was passed through a twin-screw extruder (2D25W manufactured by Toyo Seiki Kogyo Co., Ltd.; L / D = 25) for 10 minutes as the resin to be purged, leaving it in the extruder. The resin was then allowed to settle for 30 minutes by suspending the rotation of one screw. Subsequently, high-density polyethylene (HI-ZEX 7000F manufactured by Prime Polymer Co., Ltd.) was passed through the extruder for 5 minutes, and one die was removed. A cylinder was then heated to 290°C for 3 hours while air was flowed into the cylinder at a screw speed of 10 rpm, causing oxidation and deterioration of the resin to be purged. Subsequently, the resin composition (El) was fed from a hopper to the extruder for 40 minutes at a purge temperature of 110°C, a screw rotation speed of 100 rpm, and an extrusion output of 3.2 kg / hour. Then, low-density polyethylene (LC-600A, manufactured by Japan Polyethylene Corporation) was passed through the extruder for 3 minutes, followed by another 10 minutes while a cylinder was heated to 220°C. Finally, high-density polyethylene (HI-ZEX 7000F, manufactured by Prime Polymer Co., Ltd.) was passed through the extruder for 5 minutes. Amount of adhesion to the screw In each example and comparative example, the die was disassembled after the purging described above to remove the biaxial screw, and the resin adhering to the screw was collected with a copper spatula. The weight of the collected resin to be purged was measured. The results obtained are shown in Table 2. Residual properties in the hopper In each example and comparative example, the presence or absence of the resin composition that had adhered to and remained in the hopper at the time the resin composition was introduced into the hopper was visually checked and evaluated according to the following evaluation criteria. The results obtained are shown in Table 2. A: The resin composition introduced did not adhere to the hopper. B: A small amount of the introduced resin composition adhered to the hopper. 7Q7 Lnn / Zznz / E / YIAI C: A large amount of the resin introduced adhered to the hopper. Feeding capacity In each example and comparative example, the same purging operation was performed, except that a single-screw extruder (D2020 manufactured by Toyo Seiki Kogyo Co., Ltd.; L / D = 20) was used instead of the twin-screw extruder. During this operation, the feeding of the resin composition from the hopper to the extruder was visually inspected and evaluated according to the following assessment criteria. The results are shown in Table 2. A: The resin composition was automatically fed from the hopper. B: The resin composition could be fed from the hopper by using a push rod intermittently. C: The resin composition could not be fed from the hopper unless a push rod was used continuously. EXAMPLES 1 TO 19 AND 22 Purging the resin that is to be purged A residual resin to be purged from the extruder was purged in the same manner as in Example 1, except that the resin compositions (El) to (E19) shown in Table 2 were used, and the purge temperatures shown in Table 2 were employed. The results obtained are shown in Table 2. EXAMPLE 20 Purging the resin that is to be purged by means of the second purging method The purging was performed in the same manner as in Example 1, except that the residual resin to be purged in the extruder was purged instead of using the resin composition (El) by introducing 100 parts by mass of EVOH (A6) and 264 parts by mass of low-density polyethylene (di) from the extruder hopper and adding 20 parts by mass of a 10% by mass aqueous sodium carbonate solution (pH = 12.0) from a feed section of the extruder to prepare a purging agent in the extruder. The results obtained are shown in Table 2. 7Q7 Lnn / Zznz / E / YIAI EXAMPLE 21 Purging the resin to be purged using the second purging method The purging was performed in the same manner as in Example 1, except that the residual resin to be purged from the extruder was purged instead of using the resin composition (El). This was done by introducing an EVOH resin containing water, consisting of 100 parts by mass of EVOH (Al), 25 parts by mass of ion exchange water, and 264 parts by mass of low-density polyethylene (di), from the extruder hopper, and by adding 20 parts by mass of a 15% by mass aqueous sodium carbonate solution (pH = 12.0) to prepare a purging agent in the extruder. The results obtained are shown in Table 2. 7Q7 Lnn / Zznz / E / YIAI COMPARATIVE EXAMPLES 1 TO 7 Purging the Resin to be Purged A residual resin to be purged from the extruder was purged in the same manner as in Example 1, except that the resin compositions (Cl) to (C3) and (El) shown in Table 2 were used, and the purge temperatures shown in Table 2 were employed. The results obtained are shown in Table 2. TABLE 2 Resin Composition Purge Temperature (°C) Screw Adhesion Quantity (g) Residual Properties in Hopper Feed Capacity Example 1 (E1) 110 0.5 AA Example 2 (E2) 110 0.5 AA Example 3 (E3) 110 0.5 AA Example 4 (E4) 110 0.7 AA Example 5 (E5) 150 1.0 AA Example 6 (E6) 110 0.5 AA Example 7 (E7) 110 0.6 BB Example 8 (E8) 110 1.4 AA Example 9 (E9) 110 0.5 AA Example 10 (E10) 110 0 AA Example 11 (E11) 110 0.1 AA Example 12 (E12) 110 0.5 AA Example 13 (E13) 110 0.9 AA Example 14 (E14) 110 0.6 AA Example 15 (E15) 110 0.5 AA Example 16 (E16) 110 1.6 AA Example 17 (E17) 110 0.6 CB Example 18 (E18) 110 0.8 CB Example 19 (E1) 165 1.1 AA Example 20 - 110 0.5 AA Example 21 - 110 0.5 AA Example 22 (E19) 190 0.5 AA Comparative Example 1 (C1) 110 3.2 AA Comparative Example 2 (C1) 220 4.2 AC Comparative Example 3 (C2) 110 0.6 CC Comparative Example 4 (C3) 110 3.6 AA Comparative Example 5 (E1) 90 Extrusion Failure A - Comparative Example 6 (E1) 180 4.2 AB Comparative Example 7 (E1) 220 4.6 AC 7Q7 Lnn / Zznz / E / YIAI As shown in Table 2, the resin compositions (E1) to (E19) obtained in the Formulation Examples 1 to 18 were all able to efficiently discharge the resin to be purged from the molding machine extruder. In particular, when the five resin compositions (E1) to (E7) and (E9) to (E15) were used, the amount of bonding resin to be purged from the screw could be reduced to a low value of less than 1 g. This demonstrates that these resin compositions were excellent in terms of residue properties in the hopper and feed capacity. The present invention can reduce defects in products obtained using a molding machine and can also reduce the significant amount of time and material waste required to eliminate these defects. Consequently, the present invention is useful in the field of resin molding, for example.

Claims

1. A resin composition, characterized in that it comprises: a hydrophilic resin (A); water (B); and a basic compound (C), wherein the mass ratio (A) / (B) of the hydrophilic resin (A) to water (B) is 66 / 34 to 90 / 10, and the content of the basic compound (C) is 0.25 to 7 parts by mass with respect to the 100 parts by mass of the hydrophilic resin (A).

2. The resin composition according to claim 1, further characterized in that it additionally comprises another thermoplastic resin (D).

3. The resin composition according to claim 2, further characterized in that the content of the thermoplastic resin (D) is 1 to 10000 parts by mass with respect to the 100 parts by mass of the hydrophilic resin (A).

4. The resin composition according to any of claims 1 to 3, further characterized in that the hydrophilic resin (A) and water (B) are contained in the form of a water-containing hydrophilic resin obtained by mixing them. 5 - The resin composition according to any one of claims 1 to 4, further characterized in that the basic compound (C) is at least one selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, alkali metal hydroxides, ammonia, and primary to tertiary amines. 6 - The resin composition according to any of claims 1 to 3, further characterized in that the water (B) and the basic compound (C) are contained in the form of an alkaline aqueous solution obtained by mixing them together. 7 - The resin composition according to claim 6, further characterized in that the alkaline aqueous solution has a pH of 8 to 14.

8. The resin composition according to claim 6 or 7, further characterized in that the basic compound (C) is at least one selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, ammonia, and primary to tertiary amines.

9. The resin composition according to any of claims 1 to 8, further characterized in that the hydrophilic resin (A) is an ethylene vinyl alcohol copolymer.

10. The resin composition according to claim 9, further characterized in that the ethylene-vinyl alcohol copolymer has an ethylene unit content of 7Q7 Lnn / Zznz / E / YIAI 15 to 60% molar; 11.- A purging agent comprising the resin composition according to any of claims 1 to 10. 12.- A purging agent, characterized in that it comprises: a hydrophilic resin (A); and a basic compound (C), wherein the content of the basic compound (C) is 0.25 to 7 parts by mass with respect to the 100 parts by mass of the hydrophilic resin (A).

13. The purging agent according to claim 12, further characterized in that it additionally comprises another thermoplastic resin (D).

14. The purging agent according to claim 13, further characterized in that the content of the thermoplastic resin (D) is 1 to 10000 parts by mass with respect to the 100 parts by mass of the hydrophilic resin (A).

15. The purging agent according to any of claims 12 to 14, further characterized in that the basic compound (C) is at least one selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, alkali metal phosphates, alkali metal acetates, alkali metal hydroxides, ammonia, and primary to tertiary amines. 16.- The purging agent according to any of claims 12 to 15, further characterized in that the hydrophilic resin (A) is an ethylene-vinyl alcohol copolymer. 17.- The purging agent according to claim 16, further characterized in that the ethylene-vinyl alcohol copolymer has an ethylene unit content of 15 to 60% molar.

18. A method for purging a molding machine in which a resin to be purged is present, the method characterized in that it comprises the step of: supplying a resin composition containing a hydrophilic resin (A), water (B), and a basic compound (C) to the molding machine and discharging the resin composition together with the resin to be purged, wherein the mass ratio (A) / (B) of the hydrophilic resin (A) to water (B) is 90 / 10 to 66 / 34, and the content of the basic compound (C) is 0.25 to 7 parts by mass with respect to the 100 parts by mass of the hydrophilic resin (A).

19. The method according to claim 18, further characterized in that the hydrophilic resin (A), water (B), and basic compound (C) are supplied to the molding machine in the form of the purging agent according to claim 11.

20. The method according to claim 18, further characterized in that the hydrophilic resin (A) and the basic compound (C) are supplied to the molding machine in the form of the purging agent according to any of claims 12 to 17.

21. The method in accordance with any of claims 18 to 20, yaz Lnn / zznz / E / YiAi 36 further characterized in that the temperature of a melting region of the molding machine is 105°C to 230°C.

22. The purging agent according to any of claims 18 to 21, further characterized in that the hydrophilic resin (A) is an ethylene-vinyl alcohol copolymer. 5 23. The purging agent according to claim 22, further characterized in that the ethylene-vinyl alcohol copolymer has an ethylene unit content of 15 to 60% molar. 24.- A method for purging a molding machine in which a resin to be purged is present, the method characterized in that it comprises the step of: supplying an alkaline aqueous solution containing water (B) and a basic compound (C) to the molding machine and discharging the alkaline aqueous solution together with the resin to be purged.

25. The method according to claim 24, further characterized in that it additionally comprises the step of supplying a hydrophilic resin (A) and a thermoplastic resin (D) to the molding machine.

26. The purging method according to claim 24 or 25, further characterized in that the alkaline aqueous solution has a pH of 8 to 14.