JP2017193738A - Rust preventive agent and manufacturing method of rust preventive agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rust preventive agent easy to handle and capable sufficiently removing rust generated in a metallic member and suppressing regeneration of rust at the metallic member after rust removal.SOLUTION: There is provided a rust preventive agent containing 5 to 40 wt.% of phosphoric acid, 0.5 to 20 wt.% of a chelator, 0.1 to 10 wt.% of a surfactant and 0.001 to 0.1 wt.% of an urea-based compound. The chelator contains 0.2 to 15 wt.% of phosphonic acid-based chelator and 0.2 to 15 wt.% of oxycarboxylic acid-based compound. There is provided a rust preventive agent having viscosity of 3 to 7000 mPa S and, preferably, further containing polyoxyethylene as a thickener.EFFECT: Rust generated in a metallic member (target for rust removal) can be reliably removed only by bringing the rust preventive agent into contact with the metallic member and regeneration of rust on the metallic member after rust removal can be suppressed over the long term.SELECTED DRAWING: None

Description

  The present invention relates to a rust remover and a method for producing such a rust remover, and more particularly to a rust remover for removing rust generated on a metal member constituting a ship and a method for producing the same.

  A rust remover mainly composed of hydrochloric acid is used as a rust remover for removing rust generated in railway vehicles and ships. In such a rust remover, hydrochloric acid may dissolve the oxide film (non-moving film) on the metal surface together with rust. In this case, the metal member after rust removal becomes easier to rust than before the rust removal. Moreover, since such a rust removal agent has hydrochloric acid which is a strong acid as a main component, you must pay sufficient attention to the handling.

  On the other hand, as a non-hydrochloric acid-based rust remover, a rust remover mainly composed of phosphoric acid is also known (for example, Patent Document 1). In this rust remover, the phosphoric acid concentration in the rust remover must be increased in order to obtain rust removability. When the concentration of phosphoric acid in the rust remover is increased, there is an adverse effect on the human body and there is a problem with safety, and the burden on the environment is increased. Further, even if the phosphoric acid concentration in the rust remover is increased, sufficient rust removal properties cannot be obtained. Furthermore, even with a rust remover containing phosphoric acid as a main component, there is a problem that the metal member after rusting is easily rusted. In particular, since the metal member of the ship exposed to seawater will generate rust in a relatively short time after rust removal, the burden on the person engaged in the rust removal work is large.

JP-A-6-330362

  An object of the present invention is to provide a rust remover that is easy to handle and can sufficiently remove rust generated on a metal member. Moreover, it is providing the rust removal agent which can suppress that rust generate | occur | produces again in the metal member after rust removal. Another object of the present invention is to provide a method for producing a rust remover that can easily produce such a rust remover.

Such an object is achieved by the present inventions (1) to (9) below.
(1) 5-40% by weight phosphoric acid;
0.5-20 wt% chelating agent;
0.1 to 10 wt% surfactant,
0.001 to 0.1% by weight of a urea compound,
A rust remover characterized by containing.

  (2) The said chelating agent is a derusting agent as described in said (1) containing 0.2-15 weight% of phosphonic acid type chelating agents, and 0.2-15 weight% of oxycarboxylic acid type compounds.

  (3) The rust removing agent according to (1) or (2), wherein the urea compound includes a thiourea derivative.

  (4) When the phosphoric acid content in the rust remover is X [wt%] and the urea compound content is Y [wt%], the X / Y value is 10 or more and 40000. The rust remover according to any one of (1) to (3) above.

  (5) The rust remover according to any one of (1) to (4), wherein the rust remover has a viscosity of 3 to 7000 mPa · s.

(6) The rust remover according to any one of (1) to (5), further including a predetermined amount of a thickener.
(7) The said thickener is a rust remover as described in said (6) containing polyoxyethylene.

(8) A method for producing a rust remover according to any one of (1) to (5) above,
Mixing an aqueous medium and the chelating agent to obtain a first mixture;
Mixing the first mixed solution and the phosphoric acid to obtain a second mixed solution;
Mixing the second mixed solution, the surfactant and the urea compound to obtain a rust remover;
A method for producing a rust remover, comprising:

(9) A method for producing a rust remover according to any one of (1) to (6) above,
Mixing an aqueous medium and the surfactant to obtain a first mixed liquid;
Mixing the first mixed liquid and the thickener to obtain a second mixed liquid;
Mixing the second mixed solution and the chelating agent to obtain a third mixed solution;
Mixing the third mixed solution with the phosphoric acid and the urea compound to obtain a rust remover;
A method for producing a rust remover, comprising:

  According to the present invention, it is possible to reliably remove rust generated on a metal member simply by contacting the metal member (object to be removed). Moreover, it can suppress over a long period that rust regenerates to the metal member after a rust removal. Further, the rust remover of the present invention is easy to handle and has a low environmental burden. Furthermore, the rust removal property of the present invention is less likely to deteriorate even when continuously used. Therefore, the burden on the person engaged in the rust removal work can be reduced.

FIG. 1 (a) is a photograph showing a state in which red rust is generated on a SUS304 test piece (test plate), and FIG. 1 (b) shows the rust removal of Example 1 in the test piece shown in FIG. 1 (a). It is a photograph which shows the state which was immersed in the agent for 10 minutes and was washed with water after that. FIG. 2A is a photograph showing a state in which red rust is generated on the SPCC test piece (JIS G3141), and FIG. 2B is a rust removal sample of Example 1 shown in FIG. It is a photograph which shows the state which was immersed in the 10 times water dilution liquid of the agent for 10 minutes, and was washed with water after that. FIG. 3A is a photograph of a state in which red rust is generated on the deck of the ship, and FIG. 3B is a photograph of the rust remover of Example 1 and Comparative Example 2 on the deck of FIG. It is the photograph which imaged the state after apply | coating a derusting agent, leaving it to stand for 10 minutes, and washing with water, FIG.3 (c) applies the derusting agent of Example 1 to the deck of Fig.3 (a). It is the photograph which image | photographed the state after leaving to stand for 1 hour and washing with water. FIG. 4A is a photograph showing a state in which red rust is generated in the ship fall prevention chain, and FIG. 4B is a rust remover of Example 1 in which the fall prevention chain of FIG. It is a photograph which shows the state after making it soak for 30 minutes and washing with water.

Hereinafter, the rust remover of the present invention and the method for producing the rust remover will be described in detail.
<Rust remover>
First, the rust remover of the present invention will be described. The rust remover of the present invention comprises 5 to 40% by weight phosphoric acid, 0.5 to 20% by weight chelating agent, 0.1 to 10% by weight surfactant, and 0.001 to 0.1%. % By weight of a urea compound. Such a rust remover can reliably remove rust generated on the metal member only by contacting (coating or dipping) with the metal member (rust removal object). Moreover, it can suppress over a long period that rust regenerates to the metal member after a rust removal. Moreover, since this phosphoric acid content rate in a rust remover is comparatively small, this rust remover is easy to handle. Furthermore, even when this rust remover is continuously used, its rust removal property is unlikely to deteriorate. Therefore, it is effective to be used for metal members (such as a fall prevention chain and a door knob) that are easily rusted.

(phosphoric acid)
Phosphoric acid acts as a main component for removing (dissolving) rust generated in the metal member. Phosphoric acid also removes rust and acts to form a film (metal phosphate) on the surface of the metal member that has been rusted. For example, when removing rust generated on a steel member, a coating of iron phosphate is formed on the surface of the steel member, and this coating acts to suppress the rust from being regenerated on the steel member. Although the content rate of phosphoric acid is 5 to 40 weight% with respect to the whole rust removal agent, 8 to 30 weight% is preferable, 10 to 25 weight% is more preferable, and 12 to 20 weight% is the most preferable. When the phosphoric acid content is in the above range, rust can be reliably removed regardless of the material of the metal member to be rusted. Moreover, a film can be reliably formed on the surface of the rust-removed metal member, and rust can be more reliably suppressed from regenerating on the metal member. Therefore, this rust remover is particularly effective for metal members of ships that are exposed to seawater and sea breeze.

(Chelating agent)
The chelating agent acts to promote the removal of rust generated on the metal member. More specifically, the chelating agent acts to coordinate with the metal ions in the rust by a chelating action and remove the metal ions in the rust. Therefore, the rust removal property of a rust removal agent improves by a synergistic effect with phosphoric acid. Moreover, the metal ion in rust is removed by a chelating agent, so that the solubility of phosphoric acid in rust is difficult to drop. Therefore, even when the rust remover of the present invention is continuously used, its rust removal property is unlikely to deteriorate.

  Such a chelating agent is not particularly limited, and examples thereof include phosphonic acid chelating agents, aminocarboxylic acid chelating agents, oxycarboxylic acid compounds, amino acid chelating agents, and the like. Two or more kinds can be used in combination.

  Phosphonic acid-based chelating agents include 1-hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, and salts thereof including. Among these, 1-hydroxyethylidene-1,1-diphosphonic acid has a structure in which two phosphonic acids are bonded symmetrically with respect to hydroxyethylidene. Such a compound is particularly preferable because it can chelate a metal ion in one molecule and can chelate a metal ion between phosphonic acid groups of different molecules and exhibits a high chelating action.

  The aminocarboxylic acid-based chelating agent includes ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), propylenediaminetetraacetic acid (PDTA), cyclohexyldiaminotetraacetic acid (CyDTA), and salts thereof.

  Oxycarboxylic acid compounds include citric acid, lactic acid, glycolic acid, glyceric acid, tartaric acid, malic acid, hydroacrylic acid, tartronic acid, glyoxylic acid, salicylic acid, 5-hydroxyisophthalic acid, protocatechuic acid, mandelic acid, gallic acid, And their salts, hydrates and the like. Among these, citric acid and a hydrate of citric acid are particularly preferable because they have a structure having three carboxylic acids in one molecule and express a high chelating action.

  The amino acid chelating agent includes, for example, glycine, serine, alanine, lysine, cystine, cysteine, ethionine, tyrosine, methionine, and salts thereof.

  The content of the chelating agent is 0.5 to 20% by weight, preferably 1 to 15% by weight, more preferably 2 to 10% by weight, and most preferably 3 to 8% by weight with respect to the entire derusting agent. . When the content of the chelating agent is within the above range, the chelating action on the metal ions in the rust can be sufficiently enhanced, and the rust removing property of the derusting agent is further improved.

  Moreover, when using in combination of 2 or more types among the chelating agents mentioned above, it is preferable to use together a phosphonic acid type chelating agent and an oxycarboxylic acid type compound. A phosphonic acid chelating agent has a chemical structure similar to that of phosphoric acid, and is therefore a compound having good compatibility with phosphoric acid. Moreover, since oxycarboxylic acid has a hydroxyl group and carboxylic acid in its structure, it is highly compatible with phosphoric acid and phosphonic acid-based chelating agents. Therefore, the phosphoric acid, the phosphonic acid chelating agent and the oxycarboxylic acid compound in the rust remover are mixed uniformly. For this reason, the rust metal ions dissolved by phosphoric acid are efficiently chelated by the phosphonic acid chelating agent and the oxycarboxylic acid compound, and the rust removability of the rust removing agent is further improved.

  Further, when the phosphonic acid chelating agent and the oxycarboxylic acid compound are used in combination as the chelating agent, the content of the phosphonic acid chelating agent is preferably 0.2 to 15% by weight based on the entire rust removing agent, 1 to 8% by weight is more preferred, and 2 to 5% by weight is most preferred. On the other hand, the content of the oxycarboxylic acid compound is preferably 0.2 to 15% by weight, more preferably 1 to 8% by weight, and most preferably 1.5 to 5% by weight with respect to the entire rust remover.

(Surfactant)
The surfactant acts to remove (clean) dirt (paint, oil, mud, dust, etc.) adhering to the surface of the metal member. For example, when oil stains adhere to the inside of the rust or the rust surface, these oil stains are removed by the action of the surfactant, so phosphoric acid directly contacts the rust and dissolves the rust. It becomes easy. It also acts to give a glossy feeling to the surface of the metal member after rust removal.

  The surfactant includes a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant. Among these, nonionic surfactants are particularly preferable because they have good handling properties and are nonionic, and thus do not inhibit the chelating action of metal ions by a chelating agent.

  Nonionic surfactants include polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyglycerin fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene polyoxypropylene glycol, sucrose fatty acid ester, alkyl glycoside, alkyl glyceryl glycoside And methyl glucoside fatty acid ester. Among these, polyoxyalkylene alkyl ether is preferable. Polyoxyalkylene alkyl ether is preferable because it has a particularly large detergency against dirt on the surface of the metal member.

  Examples of anionic surfactants include sodium deoxycholate, sodium taurocholate, sodium cholate hydrate, N-lauroyl sarcosine sodium salt, sodium dodecyl sulfate, lithium dodecyl sulfate, alkyl sulfonate, alkyl sulfate, polyoxy Examples include ethylene alkyl ether sulfate, alkylbenzene sulfonate, and higher fatty acid ester sulfonate.

  Examples of the cationic surfactant include distearyldimethylammonium chloride, benzalkonium chloride, hexadecyltrimethylammonium bromide, myristyltrimethylammonium bromide, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, cetyltrimethylammonium chloride and the like.

  Amphoteric surfactants include N-dodecyl-N, N-dimethyl-3-ammonio-1-propanesulfonic acid, 3- (N, N-dimethylpalmitylammonio) propanesulfonic acid, 3- (N, N -Dimethyloctylammonio) propanesulfonic acid inner salt, alkylbetaine activator, amidobetaine activator, sulfobetaine activator, aminopropionic acid activator, amino acid activator and the like.

  In addition, these surfactant can be used 1 type or in combination of 2 or more types. Specifically, a combination of a nonionic surfactant and a nonionic surfactant, a combination of an anionic surfactant and an amphoteric surfactant, a combination of a nonionic surfactant and a cationic surfactant, a nonionic surfactant and an amphoteric surfactant These combinations can be freely combined.

  Moreover, although the content rate of surfactant is 0.1 to 10 weight% with respect to the whole rust remover, 0.2 to 8 weight% is preferable, 0.5 to 5 weight% is more preferable, and 0 .8 to 2% by weight is most preferred. By setting the content of the surfactant within the above range, an appropriate amount of the surfactant is included in the rust remover, so that a greater detergency can be obtained. Moreover, by making the content rate of a surfactant into the said range, the washability of the metal member surface can be improved more, maintaining the high rust removal property by phosphoric acid and a chelating agent.

(Urea compound)
The urea compound acts to prevent corrosion of the metal member surface by phosphoric acid. More specifically, the urea compound adheres to the surface of the metal member from which rust has been removed, and the metal member is prevented from being dissolved by phosphoric acid. By derusting the metal member using the rust remover of the present invention, a phosphoric acid-derived film and a urea compound-derived film are formed on the surface of the metal member after rust removal. For example, after a coating derived from a urea compound is formed on the surface of a metal member after rust removal, a coating derived from phosphoric acid is formed, or conversely, after a coating derived from phosphoric acid is formed, a urea compound is formed. A coating of origin is formed. Further, a film derived from phosphoric acid may be formed in a part of the surface of the metal member surface, and a film derived from a urea-based compound may be formed in the other area. For this reason, the metal member surface after a rust removal is protected, and it can suppress over a long period that rust regenerates to the metal member after a rust removal.

  Such urea compounds include thiourea, urea, diethylthiourea, dibutylthiourea, sulfonylurea, allylurea, guanidine, acetylthiourea, phenylurea, allantoin, 3-ureidopropyltriethoxysilane, thiosemicarbazone, guanethidine. , And derivatives or condensates thereof. Among these, it is particularly preferable to include a thiourea derivative (thiourea derivative). By using this condensate, it is possible to prevent rust from being regenerated on the metal member after rust removal for a longer period of time.

Moreover, although the content rate of a urea-type compound is 0.001-0.1 weight% with respect to the whole rust remover, 0.003-0.08 weight% is preferable, 0.005-0.06 weight % Is more preferable, and 0.01 to 0.04% by weight is most preferable. When the content rate of the urea compound is within the above range, an appropriate amount of the urea compound is included in the derusting agent, so that corrosion of the metal member surface due to phosphoric acid can be more reliably suppressed. Moreover, it can suppress over a long period that rust regenerates to the metal member after rust removal.
The rust remover of the present invention may further contain an aqueous medium and a thickener.

(Aqueous medium)
An aqueous medium acts so that the rust removal property of the rust removal agent with respect to a metal member may be adjusted. Examples of the aqueous medium include water (distilled water, ion exchange water, tap water, etc.), various alcohols, and the like.

  The content of the aqueous medium in the rust remover can be arbitrarily adjusted according to the type of metal member to be rusted and the area to be rusted, but is preferably 50 to 90% by weight with respect to the entire rust remover. 60 to 85% by weight is more preferable, and 65 to 80% by weight is most preferable.

  For example, when the metal member (the object to be removed) is a stainless steel member, it is difficult to remove the generated rust, so the removal rate of the aqueous medium in the removal agent is relatively small. Is preferably used. Further, when the metal member is an iron member, the generated rust is easier to remove than the stainless steel member, and therefore a rust remover having a relatively large content of the aqueous medium in the rust remover can be used. .

  In addition, the rust remover of this invention has very high rust removal property by including phosphoric acid, a chelating agent, surfactant, and a urea-type compound by the content rate which was mentioned above. Therefore, even if the content rate of the aqueous medium in the rust remover is sufficiently increased, the rust removability of the rust remover can be sufficiently increased. Moreover, since this rust removal agent has high rust removal property, it can be diluted with a large amount of water and used. For example, when removing a metal member such as a ship having a large rust removal area, the cost of the rust remover to be used can be reduced by diluting the rust remover with a large amount of water.

(Thickener)
The thickener acts to adjust the viscosity of the derusting agent, and is used when it is desired to thicken the derusting agent with the object to be derusted. By including a predetermined amount of thickener, the rust remover can remain on the rust removal object even when removing rust on vertical members such as door knobs, walls, and ceilings. Rust removal can be performed.

  Examples of such thickeners include polyvinyl alcohol; polyoxyethylene such as polyethylene glycol; and cellulose-based thickeners such as methylcellulose, ethylcellulose, hydroxyethylcellulose, butylcellulose, hydroxypropylcellulose, carboxyethylcellulose, ethylhydroxyethylcellulose, and hydroxypropylmethylcellulose. Agents; gums such as carrageenan, gum arabic, and xanthan gum; polysaccharides; alginates such as agar; cellulose ethers such as hydroxyalkyl cellulose ether; acrylic acid copolymers;

  Of these thickeners, polyvinyl alcohol and polyoxyethylene are preferable, and polyvinyl alcohol is more preferable. Since polyvinyl alcohol has one hydroxyl group in its repeating unit, it intermolecularly bonds with a compound having a hydroxyl group in the molecular structure. Examples of the compound having a hydroxyl group in the molecular structure include the aforementioned compounds such as phosphoric acid, phosphonic acid-based chelating agents, and oxycarboxylic acid-based chelating agents. Therefore, by including polyvinyl alcohol in the rust remover, hydrogen bonding occurs between the polyvinyl alcohol and the compound, and the rust remover is easily thickened. Moreover, even if the addition amount of polyvinyl alcohol is small, hydrogen bonds are sufficiently formed between the polyvinyl alcohol and the compound, and a high thickening effect is obtained. Therefore, even when the viscosity of the rust remover is adjusted to be high, the content of polyvinyl alcohol in the rust remover can be lowered, so that the action of each component described above is not inhibited. That is, by using polyvinyl alcohol as a thickener, the viscosity of the rust remover can be freely adjusted while maintaining the rust removability of the rust remover. Moreover, since the hydrogen bond between polyvinyl alcohol and the said compound is stable, the thickening effect is maintained over a long period of time.

  The content of the thickener is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, and most preferably 0.5 to 3% by weight with respect to the entire rust remover. Since the content of the thickener is within the above range, the effect of phosphoric acid and the effect of the thickener can be expressed in a well-balanced manner, while maintaining the rust removal property of the rust remover. The viscosity of the derusting agent can be set appropriately.

  In addition, when preparing the rust removal agent which apply | coats to vertical members, such as a door knob, a wall, a ceiling, and removes rust, the content rate of a thickener is 0.1 to 10 weight% with respect to the whole rust removal agent. It is preferable that it is 0.5 to 5 weight%, and it is most preferable that it is 1-3 weight%.

  On the other hand, when preparing a rust remover that removes rust by immersing a removable member (such as a ship fall prevention chain) or applying it to a horizontal member such as a floor, the content of thickener is rust removal. The content is preferably 0.01 to 2% by weight, more preferably 0.05 to 1.5% by weight, and most preferably 0.05 to 1% by weight based on the whole agent. Moreover, such a rust removal agent does not need to contain a thickener naturally.

(Other ingredients)
The rust remover of the present invention may contain additives such as a pH adjuster as other components in addition to the above components.

  The rust remover containing the above components is X / Y, where the phosphoric acid content in the rust remover is X [wt%] and the urea compound content is Y [wt%]. The value is preferably 10 or more and 40000 or less, more preferably 30 or more and 10,000 or less, and most preferably 50 or more and 5000 or less. By including phosphoric acid and a urea compound in the rust remover so as to satisfy the above relationship, it is possible to achieve both high rust removal properties and excellent rust prevention properties.

  In addition, when the content of phosphoric acid in the rust remover is X [wt%] and the content of the chelating agent is Z [wt%], the value of X / Z is 1 or more and 20 or less. Preferably, it is 1.2 or more and 15 or less, more preferably 2 or more and 10 or less. When the content ratio of phosphoric acid and chelating agent satisfies the above relationship, the working effect of phosphoric acid and the working effect of the chelating agent can be expressed in a well-balanced manner. Can be improved. Moreover, it can be set as the rust removal agent which the rust removal property does not deteriorate easily even if it uses continuously.

  Moreover, although the viscosity at 20 degreeC of a rust removal agent is 3-7000 mPa * s, it is preferable that it is 3-5000 mPa * s, and it is more preferable that it is 5-3000 mPa * s. By adjusting the content of the thickener contained in the derusting agent, the viscosity of the derusting agent can be freely adjusted within the above range.

  The viscosity of the low-viscosity type rust remover used for removable members and horizontal members is preferably 3 to 100 mPa · s, more preferably 3 to 50 mPa · s, and 5 to 10 mPa · s. Most preferably it is. When the viscosity of the rust remover is within such a viscosity range, the wettability of the rust remover to the metal member becomes good. Such a rust remover can more effectively remove rust when used in a metal member having a complicated shape, a fall prevention chain formed by connecting metal members, and the like.

  On the other hand, the viscosity of the high viscosity type derusting agent used for the vertical member is preferably 1000 to 7000 mPa · s, more preferably 1500 to 5000 mPa · s, and 2000 to 3500 mPa · s. Most preferred. When the viscosity of the rust remover is within such a viscosity range, the rust remover can stay on the metal member (door knob, wall, etc.) of the object to be removed for a long time. Therefore, since the contact time between the above-described component and the metal member becomes long, rust removal can be reliably performed.

  The pH of the rust remover is preferably 0.2 to 4, and more preferably 0.2 to 3. When the pH of the rust remover is within the above range, the rust removability of the rust remover is further improved.

The rust remover of the present invention is a transparent to pale yellow liquid and has no flash point.
The rust remover as described above is used, for example, to remove rust generated on a fall prevention chain, a door knob, a wall, a pipe, or the like provided in a ship or the like.

<Derusting method>
Next, a rust removal method using the rust remover of the present invention will be described. Such a rust removing method includes a step of removing rust by bringing a rust remover containing a predetermined amount of each component described above into contact with a metal member (object to be removed) where rust has occurred, and a metal member after rust removal. Washing with water.

  As a method of bringing the rust remover into contact with the metal member, when using a low viscosity type rust remover, a method of immersing the metal member in a container poured with the rust remover (immersion method), rust removal Examples thereof include a method of applying an agent to a metal member (application method), a method of spraying a rust remover on a metal member by a spraying means (spraying method), and the like. In particular, a ship fall prevention chain or the like is a member that can be detached from a ship fixture, and is very long and has a large area to be rusted. Therefore, a large amount of rust must be removed. Such metal members are preferably derusted by the dipping method described above from the viewpoint of reducing the burden on the derusting operator.

  On the other hand, when a high viscosity type rust remover is used, the above-described coating method is used. In particular, since metal members such as ship door knobs, walls, and pipes cannot be removed from the ship, high-viscosity derusting agents are applied to the metal members and left for a predetermined time to effectively remove rust. It can be carried out.

  The contact time of the rust remover to the metal member can be appropriately adjusted depending on the material of the metal member to be rusted and the amount of rust generated, but is preferably about 1 to 30 minutes, more preferably about 3 to 20 minutes. 5 to 15 minutes is most preferable. The rust remover of the present invention can surely remove rust even in such a relatively short time.

  Moreover, the temperature of the rust removal agent at the time of rust removal is not particularly limited, but is preferably about 0 to 40 ° C, more preferably about 1 to 35 ° C, and most preferably about 5 to 28 ° C. In particular, the rust remover of the present invention has a high rust removal property even at a relatively low temperature (about 1 to 2 ° C.), so even if it is used in cold districts, it reliably removes rust on metal members. can do.

  After the metal member is derusted under the above conditions, the derusting agent adhering to the metal member is removed by washing with water. The metal member can be rusted by the above method.

<Production method of rust remover>
Next, the manufacturing method of the thickener mentioned above is demonstrated. In addition, in the manufacturing method of the rust removal agent demonstrated below, the manufacturing method of the rust removal agent containing water as an aqueous medium is demonstrated.

<< Method for Producing Rust Remover Containing No Thickener >>
First, the manufacturing method of the rust removal agent which does not contain a thickener is demonstrated. The manufacturing method of this rust removal agent mixes an aqueous medium (water) and a chelating agent to obtain a first mixed solution (first step), and a first mixed solution and phosphoric acid. A step of obtaining a second liquid mixture (second step), a step of mixing the second liquid mixture, a surfactant and a urea compound, and obtaining a derusting agent (third step); including. Hereinafter, each process will be described in detail.

(First step)
The first step is a step in which an aqueous medium and a chelating agent are mixed in a container to obtain a first mixed solution. The order in which the aqueous medium and the chelating agent are put in the container is not particularly limited, and either may be first or may be simultaneous. Moreover, also when a chelating agent is used in combination of 2 or more types, the order which puts each chelating agent in a container is not specifically limited, Which may be first and may be simultaneous. Mixing of the aqueous medium and the chelating agent is performed with stirring.

  Although the temperature to mix is not specifically limited, About 10-30 degreeC is preferable. The mixing time is not particularly limited as long as the aqueous medium and the chelating agent are completely mixed, but is preferably about 1 to 10 minutes.

(Second step)
The second step is a step of obtaining a second mixed solution by mixing phosphoric acid with the first mixed solution obtained in the first step. The mixing of phosphoric acid is performed while stirring the first mixed solution.

  Although the temperature to mix is not specifically limited, About 10-30 degreeC is preferable. The mixing time is not particularly limited as long as the first mixed solution and phosphoric acid are completely mixed, but is preferably about 1 to 10 minutes.

(Third step)
The third step is a step of obtaining a rust remover by mixing a surfactant and a urea compound with the second mixed liquid obtained in the second step. The order in which the surfactant and the urea-based compound are mixed in the second mixed solution is not particularly limited, and either may be the first or simultaneous. In addition, mixing with surfactant and a urea type compound, and a 2nd liquid mixture is performed, stirring.

  Although the temperature to mix is not specifically limited, About 10-30 degreeC is preferable. Further, the mixing time is not particularly limited as long as the surfactant and the urea compound are completely mixed in the second liquid mixture, but is preferably about 1 to 10 minutes.

In addition, the 1st process-3rd process mentioned above are performed, stirring each liquid mixture (a 1st liquid mixture, a 2nd liquid mixture). It is preferable that stirring of each liquid mixture is performed so that rotation speed may be set to 200-8000 rpm, and it is more preferable to be performed so that rotation speed may be set to 300-5000 rpm. Thereby, it can fully stir in a short time.
A rust remover is obtained through the above steps.

<< Method for Producing Rust Remover Containing Thickener >>
Next, the manufacturing method of the rust removal agent containing a thickener is demonstrated. Such a method for producing a rust remover includes a step (first step) of mixing an aqueous medium (water) and a surfactant to obtain a first mixed solution, a first mixed solution and a thickener. A step of obtaining a second liquid mixture (second step), a step of mixing the second liquid mixture and the chelating agent to obtain a third liquid mixture (third step), 3 and the process (4th process) which mixes phosphoric acid and a urea type compound, and obtains a rust removal agent. Hereinafter, each process will be described in detail.

(First step)
The first step is a step in which an aqueous medium and a surfactant are mixed in a container to obtain a first mixed solution. The order in which the aqueous medium and the surfactant are put in the container is not particularly limited, and either may be first or may be simultaneous. Mixing of the aqueous medium and the surfactant is performed with stirring.

  Although the temperature to mix is not specifically limited, About 10-30 degreeC is preferable. The mixing time is not particularly limited as long as the aqueous medium and the surfactant are completely mixed, but about 1 to 10 minutes is preferable.

(Second step)
The second step is a step of obtaining a second mixed solution by mixing a thickener with the first mixed solution obtained in the first step. Mixing of the thickener is performed while stirring the first mixed solution.

  Although the temperature to mix is not specifically limited, About 10-30 degreeC is preferable. The mixing time is not particularly limited as long as the first mixed solution and the thickener are completely mixed, but is preferably about 1 minute to 24 hours.

(Third step)
A 3rd process is a process of mixing a chelating agent with the 2nd liquid mixture obtained at the 2nd process, and obtaining a 3rd liquid mixture. The chelating agent is mixed while the second mixed solution is stirred. In addition, also when a chelating agent is used in combination of 2 or more types, the order which puts each chelating agent in a 2nd liquid mixture is not specifically limited, Which may be first and may be simultaneous.

  Although the temperature to mix is not specifically limited, About 10-30 degreeC is preferable. Further, the mixing time is not particularly limited as long as the second mixed solution and the chelating agent are completely mixed, but is preferably about 1 to 10 minutes.

(Fourth process)
A 4th process is a process of mixing phosphoric acid and a urea-type compound with the 3rd liquid mixture obtained at the 3rd process, and obtaining a rust removal agent. The order in which phosphoric acid and the urea-based compound are mixed in the third mixed solution is not particularly limited, and either may be first or may be simultaneous. In addition, mixing with phosphoric acid and a urea type compound, and a 3rd liquid mixture is performed, stirring.

  Although the temperature to mix is not specifically limited, About 10-30 degreeC is preferable. The mixing time is not particularly limited as long as phosphoric acid and the urea compound are completely mixed with the third mixed solution, but about 1 to 10 minutes are preferable.

In addition, the 1st process-the 4th process mentioned above are performed, stirring each liquid mixture (a 1st liquid mixture, a 2nd liquid mixture, a 3rd liquid mixture). It is preferable that stirring of each liquid mixture is performed so that rotation speed may be set to 200-8000 rpm, and it is more preferable to be performed so that rotation speed may be set to 300-5000 rpm. Thereby, it can fully stir in a short time.
A rust remover is obtained through the above steps.

  In the above description, the derusting agent containing an aqueous medium (water) as a constituent component has been described. However, a derusting agent not containing an aqueous medium can be obtained using the same method as described above. For example, in the case of producing a rust remover that does not contain a thickener, a chelating agent and phosphoric acid are mixed in a container instead of the first and second steps described above, and the first mixed solution. After the step of obtaining the above, the third step described above may be performed.

  As mentioned above, although the rust removal agent of this invention and the manufacturing method of a rust removal agent were demonstrated, this invention is not limited to this. For example, each component constituting the rust remover can be replaced with any component that can exhibit the same function. Moreover, arbitrary components may be added to the rust remover.

  Moreover, the rust remover of this invention is used in order to remove the rust of all kinds of metal members, such as a ship, aviation, a vehicle, a building, a wall, and a handrail. In particular, as will be described later, in a ship that is exposed to seawater, the metal member is exposed to seawater or sea breeze, and it is easy to rust, and it is difficult to remove the generated rust. The rust remover of the present invention can remove rust reliably even for such a metal member, and can suppress the re-generation of rust over a long period of time. Is suitable.

Next, specific examples of the present invention will be described.
1. Production of rust remover (Example 1)
First, 739 kg of water (tap water) was placed in a container. While stirring this, 25.1 kg of chelating agent, cherest PH-210 (phosphorous acid chelating agent manufactured by Kirest Co., Ltd.) and 25.1 kg of citric acid / monohydrate (manufactured by Fuso Chemical Co., Ltd.) In order, a first mixture was obtained. Next, while stirring the first mixed solution, 200.4 kg of 75% phosphoric acid (manufactured by Daiwa Kasei Co., Ltd.) was added to the first mixed solution to obtain a second mixed solution. Next, while stirring the second mixed solution, 10 kg of Neugen XL-80 (manufactured by NOF Corporation), a surfactant, and Metallex AI (Oka Chemical Industry Co., Ltd.) containing a urea compound (thiourea derivative) 2.5 kg of made) was added to the second mixture. Thereby, a rust remover (low viscosity type rust remover not containing a thickener) was obtained.

  In the rust remover, water is 73.75% by weight, quirest PH-210 is 2.5% by weight, citric acid monohydrate is 2.5% by weight, 75% phosphoric acid is 20% by weight ( Phosphoric acid component was 15% by weight), Neugen XL-80 was 1% by weight, Metallex AI was 0.25% by weight (thiourea derivative component was 0.02% by weight).

  The pH of the rust remover was 0.5 (23 ° C.), and the viscosity of the rust remover at 20 ° C. was 6 mPa · s. The pH was measured according to JIS K 0102, and the viscosity was measured using a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) according to the regulations of JOBS 2.3.9.5-71 or JIS Z8803.

(Example 2)
Rust remover (low viscosity type rust remover) in the same manner as in Example 1 except that 779.2 kg of water, 5 kg of cherest PH-210 and 5 kg of citric acid / monohydrate were used. Got. In the rust remover, water was 77.75% by weight, Kirest PH-210 was 0.5% by weight, and citric acid / monohydrate was 0.5% by weight.

(Example 3)
First, 718.9 kg of water (tap water) was put in a container. While stirring this, 10 kg of Neugen XL-80, which is a surfactant, was added to obtain a first mixed solution. Next, while stirring the first mixed solution, 20 kg of Alcox E-75 (polyoxyethylene manufactured by Meisei Chemical Industry Co., Ltd.) as a thickener is added to the first mixed solution, and the second mixed solution is added. Obtained. Next, while stirring the second mixed liquid, 25.1 kg of chelest PH-210, which is a chelating agent, and 25.1 kg of citric acid / monohydrate are added to the second mixed liquid in this order, A third mixture was obtained. Next, 200.4 kg of 75% phosphoric acid and 2.5 kg of metallex AI, which is a urea compound, were continuously added to the third mixture while stirring the third mixture. Thereby, a rust remover (high viscosity type rust remover including a thickener) was obtained.

  In the rust remover, water is 71.75% by weight, cherest PH-210 is 2.5% by weight, citric acid monohydrate is 2.5% by weight, 75% phosphoric acid is 20% by weight ( The phosphoric acid component was 15% by weight, Neugen XL-80 was 1% by weight, Metallex AI was 0.25% by weight, and Alcox E-75 was 2% by weight.

  The pH of the rust remover was 0.5 (23 ° C.), and the viscosity of the rust remover at 20 ° C. was 2800 mPa · s. The pH was measured according to JIS K 0102, and the viscosity was measured using a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) according to the regulations of JOBS 2.3.9.5-71 or JIS Z8803.

(Comparative Example 1)
A rust remover (low viscosity type rust remover) was obtained in the same manner as in Example 1 except that 899.4 kg of water and 40 kg of 75% phosphoric acid were used. In the rust remover, water was 89.9% by weight and 75% phosphoric acid was 4% by mass (the phosphoric acid component was 3% by mass).

(Comparative Example 2)
A commercially available rust remover (manufactured by Wythetech, trade name “Super Sabinon G”) containing an organic acid as a main component was prepared.

2. Evaluation 2.1 Rust removal evaluation I
About the rust remover obtained in each Example and the rust remover obtained in Comparative Example 1, the corrosion removability (rust removal property) in a short time was evaluated as follows.

  First, a test piece of SUS304 (width 70 mm, length 70 mm, thickness 0.4 mm) was prepared. The surface of one side of the test piece was sprayed with 2% saline at a predetermined time every day for 30 days, thereby causing red rust on the test piece (the test piece was corroded).

  Next, the test piece thus corroded was brought into contact with a rust remover to remove the rust. Specifically, for Examples 1 and 2 and Comparative Example 1, the rust remover was poured into a container on which the test piece can be placed, and then the test piece was placed in the container to corrode the test piece. It was immersed in a rust remover. In addition, the immersion to the rust removal agent of the test piece was performed for 10 minutes in the state which maintained the temperature of the test piece and the rust removal agent at 20-25 degreeC. On the other hand, about Example 3, in the state which maintained the temperature of a test piece and a rust removal agent at 20-25 degreeC, after applying a rust removal agent to the corrosion surface of a test piece, it was left to stand for 10 minutes.

Thereafter, the test piece was sufficiently washed with water. About the test piece after water washing, the removal rate of the red rust before and behind rust removal was confirmed visually, and it evaluated in accordance with the following references | standards. The results are shown in Table 1.
A: Red rust could be removed.
B: Although red rust was able to be removed, it was inadequate.
C: Red rust could not be removed.

  1A is a photograph showing a state in which red rust is generated on a SUS304 test piece (test plate). FIG. 1B is a photograph showing the test piece shown in FIG. It is a photograph which shows the state immersed in the rust removal agent for 10 minutes, and was washed with water after that.

  As is clear from Table 1, the rust remover of each example was able to remove 50% or more of the red rust of the SUS304 test piece that was difficult to remove in a short time (10 minutes) (FIG. 1 (a) and (See (b)). On the other hand, with the rust remover of Comparative Example 1, the red rust of the SUS304 test piece could not be removed in a short time.

2.2 Rust removal evaluation II
About the rust remover obtained in each Example and the rust remover obtained in Comparative Example 1, the corrosion removability (rust removal) when continuously used was evaluated as follows. In addition, this evaluation pays attention to the fact that the amount of the active ingredient in the rust remover decreases by continuously using the rust remover, and a 10 times water diluted solution obtained by diluting the rust remover with water 10 times. Used.

  First, an SPCC test piece (JIS G3141, width 70 mm, length 70 mm, thickness 0.4 mm) was prepared. The surface of one side of the test piece was sprayed with a 2% saline solution at a predetermined time every day for 5 days to generate red rust on the test piece (corrosion of the test piece). In addition, the rusting of the SPCC test piece was corroded until the corroded surface became E grade with the degree of rusting described in item 6.4 (6.4.4) of JIS K2246.

  Next, the test piece which was corroded in this way was brought into contact with a 10-fold water dilution of a derusting agent to remove the rust. Specifically, for Examples 1 and 2 and Comparative Example 1, a 10-fold water dilution was poured into a container in which a test piece can be placed, and then the test piece was placed in the container to cause corrosion. The piece was immersed in a 10-fold water dilution. In addition, immersion of the test piece in the 10 times water dilution liquid was performed for 10 minutes in the state which maintained the temperature of the test piece and the rust removal agent at 20-25 degreeC. On the other hand, in Example 3, the test piece and the 10-fold water dilution solution were maintained at 20 to 25 ° C., and then the 10-fold water dilution solution was applied to the corroded surface of the test piece and left for 10 minutes.

Thereafter, the test piece was sufficiently washed with water. About the test piece after water washing, the removal rate of the red rust before and behind rust removal was confirmed visually, and it evaluated in accordance with the following references | standards. The results are shown in Table 1.
A: Red rust could be removed.
B: Although red rust was able to be removed, it was inadequate.
C: Red rust could not be removed.

  2A is a photograph showing a state in which red rust is generated on the SPCC test piece (JIS G3141). FIG. 2B is a photograph showing the test piece shown in FIG. It is a photograph which shows the state which was immersed in the 10 times water dilution liquid of a rust removal agent for 10 minutes, and was washed with water after that.

  As is clear from Table 1, the 10-fold water dilution of the rust remover of each example can remove the red rust of the SPCC test piece almost completely (98% or more) in a short time (10 minutes). (See FIGS. 2A and 2B). Therefore, it was found that the rust remover of each example hardly deteriorates when it is continuously used. On the other hand, with the rust remover of Comparative Example 1, the red rust of the SPCC test piece could not be removed in a short time. Therefore, it was found that when the rust remover of the comparative example is continuously used, its rust removing property deteriorates and is not suitable for continuous use.

2.3 Rust prevention evaluation The SPCC test piece after performing the above 2.2 Rust removal evaluation II was stored indoors at room temperature (about 23 ° C.) for 30 days. About the SPCC test piece after 30-day progress, the generation | occurrence | production state of red rust was confirmed visually and evaluated according to the following references | standards. The results are shown in Table 1. The occurrence rate of red rust was evaluated by combining the red rust observed immediately after performing the rust removal property evaluation II in 2.2 and the red rust newly generated in this evaluation.
A: Generation of red rust is not recognized.
B: Generation of red rust is observed.

  As is clear from Table 1, in the SPCC test piece derusted by the derusting agent (10-fold water dilution) of each example, it was found that the occurrence of red rust was sufficiently suppressed after derusting ( Rust is less than 2% of the total area of the SPCC specimen). On the other hand, in the SPCC test piece derusted by the derusting agent of Comparative Example 1, there was no change from the state after performing the above 2.2 derusting evaluation II.

  Thus, in the rust remover obtained in each example, excellent results were obtained in both rust removal and rust prevention. From the above results, it was found that both the rust removing property and the rust preventing property can be achieved by satisfying the above-described predetermined component of the present invention and the content thereof as in the rust remover of Examples 1 to 3.

2.4 Rust removal evaluation III
Next, with respect to the rust remover obtained in Example 1 and the rust remover of Comparative Example 2, the rust-removability of the metal part of the actual ship deck was evaluated.

  FIG. 3 (a) is a photograph of a state in which red rust has occurred on the metal part of the ship deck, and FIG. 3 (b) shows the rust remover of Example 1 on the metal part of FIG. 3 (a). It is the photograph which image | photographed the state after apply | coating the derusting agent of the comparative example 2 and leaving it to stand for 10 minutes, and washing with water, FIG.3 (c) is the rust removal of Example 1 to the metal part of Fig.3 (a). It is the photograph which image | photographed the state after apply | coating an agent, leaving it to stand for 1 hour, and washing with water.

  First, the rust remover of Example 1 and the rust remover of Comparative Example 2 were applied to the metal portion of the deck where red rust was generated as shown in FIG.

  Then, the part by which each rust removal agent of the metal part was apply | coated was fully washed with water. The state of the metal part after washing with water is shown in FIG. In FIG. 3B, “Area A” indicates an area where the rust remover of Example 1 is applied, and “Area B” indicates an area where the rust remover of Comparative Example 2 is applied. .

  As shown in FIG. 3B, most red rust was removed in the region A in a short time (10 minutes). On the other hand, in the region B, most of the red rust remained, and the red rust could not be removed sufficiently in a short time.

  Furthermore, the state after apply | coating the rust remover of Example 1 with respect to the metal part of the deck of the state of Fig.3 (a), leaving it for 1 hour, and washing with water is shown in FIG.3 (c).

  As shown in FIG.3 (c), the red rust of the deck was able to be removed almost completely by using the rust remover of Example 1. FIG.

2.5 Rust removal evaluation IV and Rust prevention evaluation II
Next, it was evaluated whether or not the derusting agent obtained in Example 1 had derusting properties with respect to the fall-preventing chain used in actual ships.

  FIG. 4A is a photograph showing a state in which red rust is generated in the ship fall prevention chain, and FIG. 4B is a rust remover of Example 1 in which the fall prevention chain of FIG. It is a photograph which shows the state after being immersed in for 30 minutes and washed with water.

  First, as shown in FIG. 4A, a fall prevention chain with red rust was prepared. Next, the rust remover of Example 1 was poured into the container, and the fall prevention chain in which red rust was generated was placed in the container and immersed in the rust remover. In addition, this immersion was performed for 30 minutes in the state which maintained the temperature of the chain for fall prevention, and the rust removal agent at 20-25 degreeC.

  Thereafter, the test piece was sufficiently washed with water. FIG. 4B shows the state of the chain for preventing fall after washing with water. As shown in FIG. 4B, the red rust removal rate before and after the rust removal was 100% when visually confirmed. Therefore, it turned out that the rust removal agent of Example 1 has the excellent rust removal property with respect to the fall prevention chain used for the actual ship.

In addition, as for metal members, such as a ship fall prevention chain, seawater adheres and it dries, and sodium chloride has adhered to the surface. A part of sodium chloride becomes chloride ions (Cl ⁻ ions), and acts as a trigger (initiator) for removing rust of phosphoric acid and a chelating agent by attacking rust. Therefore, the derusting agent obtained in Example 1 expresses particularly excellent derusting properties with respect to metal members exposed to seawater.

  Moreover, when the fall prevention chain after removing the rust was attached to the ship and the occurrence of red rust was visually confirmed after one month, the incidence of red rust was less than 5%. Since metal parts such as a ship fall prevention chain are exposed to seawater and sea breeze, they are easy to rust, but the fall prevention chain after rust removal has sufficiently suppressed red rust over a long period of time. It was found that No. 1 rust remover had excellent rust prevention properties for the fall prevention chain.

  From the above, the rust remover of the present invention obtained in Example 1 is a metal member that is easily rusted and difficult to remove the generated rust, such as a fall prevention chain used in a hull, in a short time. It was found that it can be easily rusted. Especially in large ships, the fall prevention chain is very long, and the conventional rust remover was not able to remove the rust sufficiently, so the method of removing rust using an abrasive is actually used. I came. However, by using the rust remover of the present invention, the rust removal work time can be greatly shortened (about 1/10 when using an abrasive), and the burden on the operator can be reduced. Moreover, the low-viscosity type rust remover obtained in Example 1 can be efficiently used to rust the ship floor and the like in addition to the fall prevention chain.

  In addition, the high viscosity type rust remover obtained in Example 3 should be used efficiently without dripping on vertical surfaces (members facing the vertical surface) such as door knobs, wall surfaces, and ceilings of the hull. Can do.

Claims (9)

5-40 wt% phosphoric acid,
0.5-20 wt% chelating agent;
0.1 to 10 wt% surfactant,
0.001 to 0.1% by weight of a urea compound,
A rust remover characterized by containing.   2. The derusting agent according to claim 1, wherein the chelating agent comprises 0.2 to 15 wt% of a phosphonic acid chelating agent and 0.2 to 15 wt% of an oxycarboxylic acid compound.   The rust remover according to claim 1 or 2, wherein the urea compound includes a thiourea derivative.   When the phosphoric acid content in the rust remover is X [wt%] and the urea compound content is Y [wt%], the value of X / Y is 10 or more and 40000 or less. The rust remover according to any one of claims 1 to 3.   The derusting agent according to any one of claims 1 to 4, wherein the derusting agent has a viscosity of 3 to 7000 mPa · s.   The rust remover according to any one of claims 1 to 5, further comprising a predetermined amount of a thickener.   The rust remover according to claim 6, wherein the thickener includes polyoxyethylene. A method for producing a derusting agent according to any one of claims 1 to 5,
Mixing an aqueous medium and the chelating agent to obtain a first mixture;
Mixing the first mixed solution and the phosphoric acid to obtain a second mixed solution;
Mixing the second mixed solution, the surfactant and the urea compound to obtain a rust remover;
A method for producing a rust remover, comprising: A method for producing a derusting agent according to any one of claims 1 to 7,
Mixing an aqueous medium and the surfactant to obtain a first mixed liquid;
Mixing the first mixed liquid and the thickener to obtain a second mixed liquid;
Mixing the second mixed solution and the chelating agent to obtain a third mixed solution;
Mixing the third mixed solution with the phosphoric acid and the urea compound to obtain a rust remover;
A method for producing a rust remover, comprising:

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