US20090140202A1

US20090140202A1 - Antirust agent

Info

Publication number: US20090140202A1
Application number: US11/719,097
Authority: US
Inventors: Kenichi Takahashi
Original assignee: Mitsubishi Gas Chemical Co Inc; Ryoko Chemical Co Ltd
Current assignee: Mitsubishi Gas Chemical Co Inc; Ryoko Chemical Co Ltd
Priority date: 2004-11-17
Filing date: 2005-11-15
Publication date: 2009-06-04
Also published as: CN101052747B; TW200624603A; WO2006054546A1; KR20070084290A; CN101052747A

Abstract

The present invention provides a corrosion inhibitor for preventing rusting of metallic members during long-term storage thereof while maintaining cleanness of surfaces of the metallic members, as well as a corrosion inhibiting method.

The invention provides a corrosion inhibitor containing a hydroxylamine compound represented by formula (1):

(wherein each of R¹, R², and R³represents a hydrogen atom, a C1 to C6 alkyl group, or a C2 to C4 alkenyl group, and each of these groups may have a substituent), or a hydrazine compound represented by formula (2):

(wherein each of R¹, R², R³, and R⁴represents a hydrogen atom, a C1 to C6 alkyl group, or a C2 to C4 alkenyl group, and each of these groups may have a substituent) and a water-absorbable resin; the corrosion inhibitor wrapped in a gas-permeable material; and a method of inhibiting corrosion characterized by including maintaining a metallic member in a gas barrier container in the presence of the wrapped corrosion inhibitor.

Description

TECHNICAL FIELD

The present invention relates to a corrosion inhibitor which exhibits an excellent corrosion inhibitory effect on a metallic material during storage thereof, and to a method of inhibiting corrosion.

BACKGROUND ART

Hitherto, there have been employed methods for preventing rust of metallic members caused by condensation of water vapor during storage thereof; e.g., an approach in which a metallic member is wrapped with a desiccant in a sealable material, an approach in which an object is wrapped in wrapping paper impregnated with a volatile corrosion inhibitor, and an approach in which an object is wrapped in a wrapping resin (film) containing a volatile corrosion inhibitor (see Patent Document 1). In an alternative approach, a storage container for metallic members is purged with inert gas. When the approach using a desiccant is employed, rusting cannot be prevented even under completely dry conditions, and further rusting is caused by oxygen and water which have permeated the wrapping material with elapse of time.
The conventional approach in which an object is wrapped in wrapping paper impregnated with a volatile corrosion inhibitor such as dicyclohexylammonium nitrite cannot be applied to storage of precision parts or similar parts, since a long period of time is required for fully attaining corrosion inhibitory effect through vaporization of the corrosion inhibitor, and the corrosion inhibitor component is deposited on a surface of a metallic member, thereby considerably deteriorating cleanness of the surface of the metallic member. The approach in which an object is wrapped in a wrapping resin (film) containing a volatile corrosion inhibitor attains unsatisfactory corrosion inhibitory effect during wrapping of the object, since the volatile corrosion inhibitor is lost through vaporization during production of the wrapping resin, and the volatile corrosion inhibitor which has been incorporated into the resin is difficult to vaporize.
The approach in which a storage container is purged with an inert gas such as nitrogen or argon encounters difficulty in complete removal of oxygen contained in the storage container. Even when the container is completely purged with inert gas, oxygen and water present outside the container material permeate the container with elapse of time, thereby causing rust. Thus, as mentioned above, when conventional approaches are employed, rusting of metallic members during storage thereof for a long period of time cannot be prevented simultaneously with maintaining surfaces of the metallic members clean. This raises a keen demand for solving the drawbacks.

[Patent Document 1]

Japanese Patent Application Laid-Open (kokai) No. 2003-213462

DISCLOSURE OF THE INVENTION

The present invention provides a corrosion inhibitor for preventing rusting of metallic members during long-term storage thereof while maintaining cleanness of surfaces of the metallic members, as well as a corrosion inhibiting method.
The present inventor has found that, when a metallic member is hermetically maintained in a gas barrier container where a corrosion inhibitor package product containing a hydroxylamine or hydrazine compound serving as an essential component and a water-absorbable resin retaining the compound is present, rusting of the metallic member can be prevented with maintaining cleanness of a surface of the metallic member. The present invention has been accomplished on the basis of this finding.
Accordingly, the present invention is directed to the following.
1. A corrosion inhibitor comprising a hydroxylamine compound represented by formula (1):
(wherein each of R¹, R², and R³represents a hydrogen atom, a C1 to C6 alkyl group, or a C2 to C4 alkenyl group, and each of these groups may have a substituent), or a hydrazine compound represented by formula (2):
(wherein each of R¹, R², R³, and R⁴represents a hydrogen atom, a C1 to C6 alkyl group, or a C2 to C4 alkenyl group, and each of each of these groups may have a substituent) and a water-absorbable resin.
2. A package product comprising the corrosion inhibitor as recited in 1 above and a gas-permeable material which wraps the corrosion inhibitor.
3. A method of inhibiting corrosion, comprising maintaining a metallic member in a gas barrier container in the presence of the package product as recited in 2 above.
The metal corrosion inhibitor of the present invention exhibits an excellent inhibitory effect on rusting of a metallic material caused by condensation of water vapor during storage thereof, and is able to maintain cleanness of surfaces of metallic members. Therefore, when the corrosion inhibitor is employed, a washing step (including rust removal and or cleaning metal surfaces), which would otherwise be required in metal processing (plating, painting, etc.) after storage of the metallic members, can be eliminated, whereby processing time and cost for chemical liquids can be reduced.

BEST MODES FOR CARRYING OUT THE INVENTION

The metal corrosion inhibitor of the present invention is generally applied to iron. However, the corrosion inhibitor is also applicable to other metal species such as copper, nickel, chromium, cobalt, lead, zinc, aluminum, titanium, tin, gold, silver and alloys thereof. These metallic species may be ground/cut products, die-cast molds, sintered products, etc. The corrosion inhibitor may be applied to metallized products made of a material such as resin, glass, or ceramic material, whose surfaces are metallized through adhesion, pressing, plating, vapor deposition, ion-plating, or similar means.
Specific examples of preferred hydroxylamine compounds represented by formula (1) include hydroxylamine, O-methylhydroxylamine, O-ethylhydroxylamine, N-methylhydroxylamine, N,N-dimethylhydroxylamine, N,O-dimethylhydroxylamine, N-ethylhydroxylamine, N,N-diethylhydroxylamine, N,O-diethylhydroxylamine, O,N,N-trimethylhydroxylamine, N-(2-methoxyethyl)hydroxylamine, N-allylhydroxylamine, N,O-diallylhydroxylamine, and O-cyclohexyl-N,N-dimethylhydroxylamine. Of these, hydroxylamine and N,N-diethylhydroxylamine are most preferred.
Specific examples of hydrazine compounds represented by formula (2) include hydrazine, methylhydrazine, ethylhydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, 1,1-diethylhydrazine, 1,2-diethylhydrazine, isopropylhydrazine, 1,2-diisopropylhydrazine, cyclohexylhydrazine, and allylhydrazine. Of these, hydrazine, methylhydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, ethylhydrazine, 1,1-diethylhydrazine, and 1,2-diethylhydrazine are most preferred.
The corrosion inhibitor of the present invention preferably has a hydroxylamine compound concentration or a hydrazine compound concentration of 0.001 to 50 wt. %, more preferably 0.05 to 30 wt. %, particularly preferably 0.5 to 30 wt. %. When the concentration is less than 0.001 wt. %, the corrosion inhibitory effect is unsatisfactory, whereas when the concentration is in excess of 50 wt. %, the effect does not improve any further, therefore inappropriate for economical reasons.
In the present invention, when an immediate corrosion inhibitory effect is demanded, the composition containing the aforementioned hydroxylamine compound or hydrazine compound and an additional acetylene alcohol is preferably absorbed in water-absorbable resin. Examples of preferred acetylene alcohols include C3 to C10 acetylene alcohols such as 1-propyn-3-ol, 1-butyn-3-ol, 1-butyn-4-ol, 2-butyn-1-ol, 3-methyl-1-butyn-3-ol, 3-methyl-1-butyn-4-ol, 1-pentyn-3-ol, 3-methyl-1-pentyn-3-ol, 1-hexyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, 1-heptyn-3-ol, 1-octyn-3-ol, 1-nonyn-3-ol, 1-decyn-3-ol, 2-butyn-1,4-diol, 3-hexyn-2,5-diol, 3,5-dimethyl-3-hexyn-2,5-diol, and 4-ethyl-1-octyn-3-ol. Of these, 3-methyl-1-pentyn-3-ol (methylpentynol), 3-methyl-1-butyn-3-ol (methylbutynol), 3,5-dimethyl-1-hexyn-3-ol (dimethylhexynol), 1-ethynylcyclohexanol, etc. are most preferred. The corrosion inhibitor of the present invention preferably has an acetylene alcohol concentration of 0.001 to 50 wt. %, more preferably 0.01 to 10 wt. %, particularly preferably 0.1 to 10 wt. %. When the acetylene alcohol concentration is less than 0.001 wt. %, the corrosion inhibitory effect is unsatisfactory, whereas when the concentration is in excess of 50 wt. %, the effect does not improve any further, therefore inappropriate for economical reasons.
The water-absorbable resin of the present invention is formed of a swellable polymer which has a crystalline or cross-linked structure, which allows rapid absorption of water when in contact with water. Examples of such polymers include polyvinyl alcohol, poly(meth)acrylate salts, poly(meth)acrylamide, polysulfonate salts, polyethylene oxide, carboxymethyl cellulose, acrylate salt-acrylate ester copolymers, vinyl acetate-acrylate ester copolymers, and starch-acrylic acid graft copolymer hydrolyzates. Preferably, the water-absorbable resin is a hardened resin obtained through reaction essentially between a hydrophilic epoxy resin (a) having two or more epoxy groups in a molecule thereof and an amine compound (b) having two or more primary or secondary amine groups in a molecule thereof.
No particular limitation is imposed on the species of the aforementioned epoxy resin (a), so long as the epoxy resin is a hydrophilic compound having two or more epoxy groups in a molecule thereof. Specific examples include polyether-type epoxy resins obtained through reaction between epichlorohydrin and a glycol such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, or polypropylene glycol; and polyhydric alcohol-type epoxy resins obtained through reaction between epichlorohydrin and a polyhydric alcohol such as glycerin, polyglycerol, trimethylolpropane, or sorbitol. Of these, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, and a mixture thereof are most preferred. The epoxy resin preferably has an epoxy equivalent of 130 to 1,500 g/eq, more preferably 200 to 1,000 g/eq.
No particular limitation is imposed on the species of the aforementioned amine compound (b), so long as the amine compound has two or more primary or secondary amino groups in a molecule thereof. Specific examples include aliphatic primary amines such as ethylenediamine, polyethylenediamine, polyether-diamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and xylylenediamine; alicyclic primary amines such as bis(aminomethyl)cyclohexane, and isophoronediamine; aromatic primary amines such as m-phenylenediamine and diaminodiphenylmethane; aliphatic secondary amines such as ethylene oxide adducts of an amine such as ethylenediamine, polyethylenediamine, polyether-diamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or xylylenediamine; alicyclic secondary amines such as ethylene oxide adducts of an amine such as bis(aminomethyl)cyclohexane or isophoronediamine; piperazine; and dicyan diamide. Of these, polyethylenediamine, polyether-diamine, xylylenediamine, bis(aminomethyl)cyclohexane, and isophoronediamine are most preferred.
The aforementioned water-absorbable resin preferably has a ratio of epoxy resin (a) to amine compound (b) of 1:0.3 to 1:3, as represented by an equivalent ratio (epoxy equivalent:active hydrogen equivalent) of epoxy group amount of epoxy resin (a):amount of hydrogen atoms directly bonded to amine nitrogen atoms of amine compound (b), more preferably 1:0.6 to 1:2.5, particularly preferably 1:0.7 to 1:2.2.
When the aforementioned epoxy resin (a) and amine compound (b) are treated at 0 to 150° C. for 1 to 48 hours, preferably at 40 to 120° C. for 2 to 10 hours, a hardened water-absorbable resin can be produced.
In the above hardening process, a generally known hardening accelerator may be added in order to control hardening rate. Examples of such hardening accelerators include tertiary amines, imidazoles, and derivatives thereof.
No particular limitation is imposed on the method for retaining an essential member of the present invention; i.e., hydroxylamine compound or hydrazine compound, in water-absorbable resin. For example, the water-absorbable resin is pulverized to an appropriate particle size, and the pulverized resin is immersed in an aqueous solution of hydroxylamine compound or hydrazine compound at 5 to 100° C. for 0.5 to 72 hours, whereby the compound can be retained in the water-absorbable resin.
The corrosion inhibitor of the present invention, formed of a water-absorbable resin in which an essential component; i.e., the hydroxylamine or hydrazine compound, has been retained, is employed as a package product containing the essential component wrapped in a wrapping material having gas permeability, which has an oxygen permeability of 1,000 mL/m²·day·atm or higher at 25° C. and 60% RH. No particular limitation is imposed on the type of gas-permeable wrapping material and the structure of the package product. In one exemplary procedure, a water-absorbable resin which retains an essential component; i.e., a hydroxylamine or hydrazine compound, is charged into a gas-permeable wrapping material of laminated structure having a substrate made of paper, nonwoven fabric, perforated plastic film or sheet, etc., and the periphery of the wrapping material is sealed by heat, to thereby produce a package product containing the essential component wrapped in the wrapping material.
The corrosion inhibitor in the form of the above package product is hermetically placed in a gas-barrier container with a metallic object to be stored. The gas-barrier container employed is a bag, a casing, a can, or a like container, which is made of a gas-barrier plastic or metallic material. For example, the gas-barrier container may be a casing made of a resin such as polyethylene, polypropylene, nylon, polyester, vinyl chloride, or polystyrene, or a bag made of a laminate film or sheet material formed of polyethylene, polypropylene, nylon, polyester, or a similar polymer.
In the case where the gas-barrier material is plastic film or sheet, a coating such as aluminum, silicon oxide, or selenium oxide may be vapor-deposited on a surface of the film or sheet employed, in order to ensure gas-barrier performance. Other than the aforementioned materials, metallic cans made of iron, aluminum, stainless steel, etc. may be employed. The gas-barrier container preferably has an oxygen permeability of 50 mL/m²·day·atm or less at 25° C. and 60% RH, and a steam permeability of 5 g/m²day or less at 40° C. and 90% RH, more preferably an oxygen permeability of 10 mL/m²·day·atm or less at 25° C. and 60% RH, and a steam permeability of 1 g/m²·day or less at 40° C. and 90% RH.

EXAMPLES

The present invention will next be described in detail by way of The Examples and Comparative Examples, which should not be construed as limiting the invention thereto.

Example 1

Polyethylene glycol diglycidyl ether (Denacol EX-841, product of Nagase Chemicals Ltd., epoxy equivalent: 370 g/eq) (82 parts) and glycerol polyglycidyl ether (Denacol EX-313, product of Nagase Chemicals Ltd., epoxy equivalent: 141 g/eq) (2 parts) (epoxy equivalent:active hydrogen equivalent=1:2.0), which had been heated to 60° C. in advance, were placed in a 500-mL beaker. To the mixture, benzyldimethylamine (0.1 parts) serving as a hardening accelerator was added, and the mixture was stirred. To the mixture, m-xylenediamine (active hydrogen equivalent: 34 g/eq) (16 parts) was added, and the mixture was stirred. The solution mixture was poured into an aluminum mold and heated in a drier at 80° C. for one hour and further at 120° C. for one hour, to thereby produce a hardened resin product. The hardened resin product was pulverized by means of a mortar, and the pulverized product (3 g) was immersed in a 5 wt. % aqueous hydroxylamine solution (100 mL) at 25° C. for 24 hours. Subsequently, the thus-water-absorbed hydroxylamine-containing hardened resin product (percent water absorption: 300 wt. %, hydroxylamine content: 5 wt. %) was charged into a gas-permeable wrapping material (inside dimensions: 80 mm×50 mm, oxygen permeability 1,000 mL/m²·day·atm) of laminate structure formed of paper/polyethylene film, and the periphery of the wrapping material was sealed by heat such that the resin was held by the polyethylene film, to thereby produce a corrosion inhibitor package product. The corrosion inhibitor package product was subjected to the volatile corrosion inhibitor test (JIS-Z-1519). After completion of the test, the rust status of the test pieces was visually observed, and the status was evaluated on the basis of the following three ratings. The results are shown in Table 1.
A: No rusting
B: Rust observed on <50% surface of a test piece
C: Rust observed on ≧50% surface of a test piece

Example 2

The procedure of Example 1 was repeated, except that a 5 wt. % hydrazine was used instead of a 5 wt. % hydroxylamine. The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 3

The procedure of Example 1 was repeated, except that a 5 wt. % N,N-diethylhydroxylamine was used instead of a 5 wt. % hydroxylamine. The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 4

The procedure of Example 1 was repeated, except that a 5 wt. % methylhydrazine was used instead of a 5 wt. % hydroxylamine. The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 5

The procedure of Example 1 was repeated, except that a 5 wt. % ethylhydrazine was used instead of a 5 wt. % hydroxylamine. The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 6

The procedure of Example 1 was repeated, except that a 5 wt. % 1,1-dimethylhydrazine was used instead of a 5 wt. % hydroxylamine. The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 7

The procedure of Example 1 was repeated, except that a 5 wt. % 1,2-dimethylhydrazine was used instead of a 5 wt. % hydroxylamine. The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 8

The procedure of Example 1 was repeated, except that polyethylene glycol diglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd., epoxy equivalent: 551 g/eq) (91.5 parts) and m-xylenediamine (8.5 parts) (epoxy equivalent active hydrogen equivalent=1:1.76) were added instead of polyethylene glycol diglycidyl ether (Denacol EX-841) (82 parts), glycerol polyglycidyl ether (2 parts), and m-xylenediamine (16 parts). The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 9

The procedure of Example 1 was repeated, except that polyethylene glycol diglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd.) (86 parts), polypropylene glycol diglycidyl ether (Denacol EX-920, product of Nagase Chemicals Ltd., epoxy equivalent: 176 g/eq) (8 parts), benzyldimethylamine (1 part), and isophoronediamine (active hydrogen equivalent: 43 g/eq) (6 parts) (epoxy equivalent active hydrogen equivalent=1:1.77) were added instead of polyethylene glycol diglycidyl ether (Denacol EX-841) (82 parts), glycerol polyglycidyl ether (2 parts), benzyldimethylamine (0.1 parts), and m-xylenediamine (16 parts). The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 10

The procedure of Example 1 was repeated, except that polyethylene glycol diglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd.) (86.6 parts), benzyldimethylamine (1 part), and 1,3-bis(aminomethyl)cyclohexane (active hydrogen equivalent: 36 g/eq) (11.4 parts) (epoxy equivalent:active hydrogen equivalent=1:2.02) were added instead of polyethylene glycol diglycidyl ether (Denacol EX-841) (82 parts), glycerol polyglycidyl ether (2 parts), benzyldimethylamine (0.1 parts), and m-xylenediamine (16 parts). The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 11

The procedure of Example 1 was repeated, except that polyethylene glycol diglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd.) (88.3 parts) and triethylenetetramine (active hydrogen equivalent: 37 g/eq) (11.7 parts) (epoxy equivalent:active hydrogen equivalent=1:2.02) were added instead of polyethylene glycol diglycidyl ether (Denacol EX-841) (82 parts), glycerol polyglycidyl ether (2 parts), and m-xylenediamine (16 parts). The results of the volatile corrosion inhibitor test are shown in Table 1.

Comparative Example 1

The procedure of Example 1 was repeated, except that pure water was used instead of an aqueous hydroxylamine. The results of the volatile corrosion inhibitor test are shown in Table 1.

Comparative Example 2

The procedure of Example 1 was repeated, except that silica gel (5 g) was used instead of a water-absorbable resin. The results of the volatile corrosion inhibitor test are shown in Table 1.

Comparative Example 3

The procedure of Example 1 was repeated, except that activated carbon (5 g) was used instead of a water-absorbable resin. The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 12

Polyethylene glycol diglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd., epoxy equivalent: 551 g/eq) (88.3 parts) was placed in a 500-mL beaker, and ion-exchange water (100 parts) was added, followed by stirring the mixture at 60° C. To the mixture, triethylenetetramine (active hydrogen equivalent: 37 g/eq) (11.7 parts) (epoxy equivalent:active hydrogen equivalent 1:1.97) was added, and the mixture was further stirred. The resultant mixture was heated in a drier at 80° C. for two hours, to thereby produce a hardened resin product. The hardened resin product was pulverized by means of a mortar, and the pulverized product (5 g) was immersed in an aqueous solution (100 mL) of 1 wt. % 1,1-diethylhydrazine and 0.1 wt. % methylpentynol at 25° C. for five hours. From the thus-immersed hardened resin product, and in a manner similar to that of Example 1, a corrosion inhibitor package product was produced. The product was subjected to the volatile corrosion inhibitor test. The results are shown in Table 1.

Example 13

The procedure of Example 12 was repeated, except that 0.1 wt. % methylbutynol was used instead of 0.1 wt. % methylpentynol. The results of the volatile corrosion inhibitor test are shown in Table 1.

Example 14

Polyethylene glycol diglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd., epoxy equivalent: 551 g/eq) (60 parts) was placed in a 500-mL beaker, and benzyldimethylamine (0.2 parts) and ion-exchange water (100 parts) were added, followed by stirring the mixture. To the mixture, polyether-diamine (active hydrogen equivalent: 500 g/eq) (40 parts) (epoxy equivalent:active hydrogen equivalent=1:0.73) was added, and the mixture was further stirred. The resultant mixture was heated in a drier at 80° C. for two hours and at 90° C. for three hours, to thereby produce a hardened resin product. The hardened resin product was pulverized by means of a mortar, and the pulverized product (5 g) was immersed in an aqueous solution (100 mL) of 1 wt. % 1,2-diethylhydrazine and 0.1 wt. % dimethylhexynol at 25° C. for five hours. From the thus-immersed hardened resin product, and in a manner similar to that of Example 1, a corrosion inhibitor package product was produced. The product was subjected to the volatile corrosion inhibitor test. The results are shown in Table 1.

Example 15

The procedure of Example 14 was repeated, except that wt. % 1-ethynylcyclohexanol was used instead of 0.1 wt. % dimethylhexynol. The results of the volatile corrosion inhibitor test are shown in Table 1.

	TABLE 1

	Rust status

	Example 1	A
	Example 2	A
	Example 3	A
	Example 4	A
	Example 5	A
	Example 6	A
	Example 7	A
	Example 8	A
	Example 9	A
	Example 10	A
	Example 11	A
	Example 12	A
	Example 13	A
	Example 14	A
	Example 15	A
	Comp. Ex. 1	C
	Comp. Ex. 2	B
	Comp. Ex. 3	C

Claims

1. A corrosion inhibitor comprising a hydroxylamine compound represented by formula (1):

(wherein each of R¹, R², R³, and R⁴represents a hydrogen atom, a C1 to C6 alkyl group, or a C2 to C4 alkenyl group, and each of these groups may have a substituent) and a water-absorbable resin.

2. The corrosion inhibitor as described in claim 1, wherein the compound represented by formula (1) is hydroxylamine or N,N-diethylhydroxylamine.

3. The corrosion inhibitor as described in claim 1, wherein the compound represented by formula (2) is at least one species selected from among hydrazine, methylhydrazine, ethylhydrazine, 1,1- or 1,2-dimethylhydrazine, and 1,1- or 1,2-diethylhydrazine.

4. The corrosion inhibitor as described in claim 1, which further contains a C3 to C10 acetylene alcohol.

5. The corrosion inhibitor as described in claim 4, wherein the acetylene alcohol is at least one species selected from among 3-methyl-1-pentyn-3-ol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and 1-ethynylcyclohexanol.

6. The corrosion inhibitor as described in claim 1, wherein the water-absorbable resin is a hardened resin obtained through reaction between a hydrophilic epoxy resin (a) having two or more epoxy groups in a molecule thereof and an amine compound (b) having two or more primary or secondary amine groups in a molecule thereof.

7. The corrosion inhibitor as described in claim 6, wherein the epoxy resin (a) is at least one species selected from the group consisting of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether, and polyglycerol polyglycidyl ether.

8. The corrosion inhibitor as described in claim 6, wherein the amine compound (b) is at least one species selected from the group consisting of polyethylenediamine, polyether-diamine, xylylenediamine, bis(aminomethyl)cyclohexane, and isophoronediamine.

9. A package product comprising a corrosion inhibitor as recited in claim 1 and a gas-permeable material which wraps the corrosion inhibitor.

10. A method of inhibiting corrosion, comprising maintaining a metallic member in a gas barrier container in the presence of the corrosion inhibitor as described in claim 1.

11. The corrosion inhibitor as described in claim 2, wherein the compound represented by formula (2) is at least one species selected from among hydrazine, methylhydrazine, ethylhydrazine, 1,1- or 1,2-dimethylhydrazine, and 1,1- or 1,2-diethylhydrazine.

12. The corrosion inhibitor as described in claim 11, which further contains a C3 to C10 acetylene alcohol.

13. The corrosion inhibitor as described in claim 12, wherein the acetylene alcohol is at least one species selected from among 3-methyl-1-pentyn-3-ol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and 1-ethynylcyclohexanol.

14. The corrosion inhibitor as described in claim 7, wherein the amine compound (b) is at least one species selected from the group consisting of polyethylenediamine, polyether-diamine, xylylenediamine, bis(aminomethyl)cyclohexane, and isophoronediamine.

15. A package product comprising a corrosion inhibitor as recited in claim 11 and a gas-permeable material which wraps the corrosion inhibitor.

16. A package product comprising a corrosion inhibitor as recited in claim 4 and a gas-permeable material which wraps the corrosion inhibitor.

17. A method of inhibiting corrosion, comprising maintaining a metallic member in a gas barrier container in the presence of the corrosion inhibitor as described in claim 11.

18. A method of inhibiting corrosion, comprising maintaining a metallic member in a gas barrier container in the presence of the corrosion inhibitor as described in claim 4.