JP2013060511A - Cleaning liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning liquid controlling rust development on the surface of a mold after cleaning.SOLUTION: This cleaning liquid includes dimethyl sulfoxide and a three kinds mixture of monoester, diester and triester of fatty acid glyceryl. The mixing ratio of monoester, diester and triester of fatty acid glyceryl, is preferably (monoester):(diester):(triester)=(30-70):(20-60):(1-30), more preferably (monoester):(diester):(triester)=(40-60):(30-50):(2-20).

Description

  The present invention relates to a cleaning liquid, and more particularly to a mold cleaning liquid.

  There is a casting method as one of methods for processing metal into various shapes. The casting method is a technique in which molten metal is poured into a mold and then cured and taken out. There are various casting methods. For example, a cured product of resin and foundry sand is used as a mold.

  In a casting method using a cured product of resin and foundry sand as a mold, a mixture of resin and foundry sand is first poured into a mold and cured by amines or heat to form a mold. Next, the mold is removed from the mold, and the metal melted at a high temperature is poured into the mold. After the metal is cured, the metal is taken out from the mold.

  When molding of the mold is repeated, the cured product of resin and sand gradually adheres to the mold surface. Since some molds require extremely high accuracy, repeated use of the mold will hinder the quality of the mold, and therefore, it is necessary to frequently remove the fixed matter.

  For removing the fixed matter, a method using a physical method such as a hammer, brush, air blast, a method of removing by dissolving or swelling using an appropriate solvent, or a method combining these two methods is used. . In a mold having a complicated structure, it is difficult to remove the sticking matter only by the automatic cleaning method. Therefore, there are cases where it is necessary to remove the fixed matter by hand, and the frequency with which a person comes into contact with the cleaning liquid at the time of manual work increases. Therefore, the composition is preferably less harmful. In the cleaning field, use of solvents that may be harmful is refraining from use, and there is a tendency to shift to less harmful cleaning solvents.

  Dimethyl sulfoxide (hereinafter sometimes referred to as DMSO) is a solvent that simultaneously satisfies detergency and low toxicity, and its application as an alternative to a cleaning solution that uses a highly harmful solvent is expanding. However, rust occurs depending on the material of the cleaning surface compared to other cleaning solvents. If even a small amount of rust remains, the mold will be defective, and in order to remove the rust, a separate process must be provided. As a result, productivity is lowered, which becomes a serious problem. For example, Patent Document 1 proposes a mold cleaning solution containing DMSO and an anionic surfactant or a fluorosurfactant, but has a low rust prevention effect.

JP 59-153542 A

  It is an object of the present invention to provide a cleaning liquid that suppresses rusting on the mold surface after cleaning. In particular, the present invention is to provide a cleaning liquid mainly composed of DMSO, which is most suitable for a mold that removes resin and sand fixed to a mold from which a mold has been removed.

  In order to achieve the above object, the cleaning liquid of the present invention has the following composition. In other words, the fatty acid glyceryl is a cleaning solution containing a mixture of three kinds of monoester, diester, and triester and dimethyl sulfoxide.

  The cleaning liquid containing DMSO of the present invention has a surface on the mold surface, compared with a cleaning liquid mainly composed of DMSO, by adding a mixture of three kinds of fatty acid glyceryl, monoester, diester and triester. After removing the adhering foundry sand and resin, rusting on the mold surface can be suppressed.

  In particular, the cleaning liquid of the present invention can effectively clean the surface of a mold used at the time of producing a mold used when a metal is processed by a casting method. Furthermore, the cleaning liquid of the present invention removes the molding sand and resin adhering to the mold surface and removes rust on the mold surface when the mold made of a cured resin and molding sand is released from the mold. Can be suppressed.

FIG. 1 is a schematic view of a test piece in which rust (black portion in the figure) has occurred. FIG. 2 is a top view of FIG. Rust generation rate was calculated by dividing by squares (20 × 20)

  The present invention is a mold cleaning liquid in which a mixture of three kinds of monoester, diester, and triester of fatty acid glyceryl is added to DMSO.

  There is no restriction | limiting in particular in the manufacturing method of DMSO used by this invention. For example, DMSO is obtained by oxidation of dimethyl sulfide.

  Monoesters and diesters of fatty acid glyceryl have general formulas depending on the site of dehydration reaction,

(In the formula, R ₁ is a fatty chain site of fatty acid glyceryl.)

(Wherein R ₁ and R ₂ are fatty chain sites of fatty acid glyceryl and may be the same or different), but any combination of structures may be used.

  The fatty acid glyceryl diester and triester may have the same or different fatty chain sites in the molecule.

  The carbon number of the carbon chain in the fatty chain portion of the fatty acid glyceryl is preferably 12-20. If the number of carbon atoms is less than 12, the rust prevention effect may be reduced. When there are more than 20 carbon atoms, it may be difficult to dissolve in DMSO. Specific examples of the fatty chain site include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid and the like. These fatty chains may be a simple substance, or monoesters, diesters, and triesters may be composed of esters of different types of fatty chains. Moreover, the carbon chain of the fatty acid moiety of the fatty acid glyceryl may be linear or branched.

  The fatty acid glyceryl used in the present invention is more preferably glyceryl monooleate, glyceryl dioleate, or glyceryl trioleate.

  There is no particular limitation on the method for producing a mixture of monoester, diester and triester of fatty acid glyceryl used in the present invention. For example, a mixture of monoester, diester and triester of fatty acid glyceryl can be obtained by esterification by dehydration reaction of fatty acid and glycerin under acidic conditions.

  The mixing ratio of monoester, diester and triester of fatty acid glyceryl is preferably monoester: diester: triester = 30 to 70:20 to 60: 1 to 30, more preferably monoester: diester: tri Esters = 40 to 60:30 to 50: 2 to 20. From the examination of the rust prevention effect, if any one of the mixing ratios of the three components is 0, the rust prevention effect is lowered.

  The content of the mixture of three kinds of fatty acid glyceryl monoester, diester, and triester in the cleaning liquid is preferably 0.1 to 5.0% by weight, more preferably 0.5 to 3.0% by weight. is there. If the content of the mixture of three kinds of fatty acid glyceryl monoester, diester, and triester is less than 0.1% by weight, the rust preventive power may be weakened. When the amount is more than 5.0% by weight, the cleaning power is lowered and the cleaning liquid may be separated.

    The cleaning liquid of the present invention preferably has the general formula

(In the formula, R represents an aralkyl group having 7 to 13 carbon atoms which may have a substituent).

    The amine is preferably of the general formula:

(Wherein R ₁ is any _one of hydrogen, hydroxyl group, tert-butyl group, methyl group and methoxy group, and R ₂ is any one of hydrogen, methyl group and methoxy group).

  Examples of amines include benzylamine, 2,4-dimethoxybenzylamine, 4-tert-butylbenzylamine, 2,3-dimethylbenzylamine, 2-methoxybenzylamine, 4-methoxybenzylamine, 4-hydroxybenzylamine and the like. Of these, benzylamine is preferred from the viewpoint of improving the detergency of the cleaning liquid, being less harmful and easily industrially available.

  The content of the amine in the cleaning solution is preferably 5 to 50% by weight, more preferably 10 to 20% by weight. If the added amount of amine is less than 5% by weight, the detergency may decrease. If it is more than 30% by weight, harmfulness and odor may be a problem.

  There is no restriction | limiting in particular in the manufacturing method of the amine used by this invention. It can be obtained by a method of reacting ammonia or amine with an alkyl halide or the like, or a method of reducing a nitro group, oxime, amide or the like.

  The content of DMSO (melting point: 18.4 ° C.) in the cleaning liquid is preferably 60 to 95% by weight in order to maintain cleaning power and maintain workability without solidifying the cleaning liquid in winter. More preferably, it is 70 to 80% by weight.

  In addition, the cleaning liquid containing DMSO of the present invention can be blended with other components, for example, water or an organic solvent, if necessary, for example, to lower the freezing point.

  Examples of the organic solvent include alcohols such as methanol, ethanol, isopropyl alcohol, 1-butanol, cyclohexanol, heptanol, N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide and the like. Amides, lactams such as N-methyl-2-pyrrolidone and N-ethyl-pyrrolidone, imidazolidinones such as 1,3-dimethyl-2-imidazolidinone and 1,3-diethyl-2-imidazolidinone , Lactones such as γ-butyrolactone, δ-valerolactone, glycols such as ethylene glycol, diethylene glycol, ethylene glycol monomethyl ether, ethers such as 1,3-dioxane, 1,4-dioxane, nitriles such as acetonitrile Etc. From the need of maintaining the detergency of the cleaning liquid by the addition, low toxicity, and low odor, alcohols are preferable, ethanol and isopropyl alcohol are more preferable, and ethanol is more preferable. The content of ethanol in the cleaning solution is preferably 10 to 30% by weight, more preferably 15 to 20% by weight. If the amount of ethanol added is less than 10% by weight, it will solidify in winter and workability will decrease. When the addition amount is more than 30% by weight, the cleaning power is lowered.

  There is no restriction | limiting in particular in the manufacturing method of ethanol used for this invention. It is obtained by a method of decomposing saccharides such as glucose using yeast or a hydration reaction of ethylene.

  Although there is no restriction | limiting in particular as a casting_mold | template manufacturing method used as the object of washing | cleaning by this invention, the shell mold method (The method which mixes furan resin and quartz sand, and hardens | cures with a mold by heat | fever and obtains a casting_mold | template) And a method of obtaining a mold by mixing a phenol resin, an isocyanate resin, and silica sand, and spraying and curing amines on a mold.

  The cleaning liquid of the present invention can be preferably used as a mold cleaning liquid, and can be used for removing a resin or foundry sand fixed to the surface of a mold used for forming a mold of a machine part or the like.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Test method Polish the test piece (material: cast iron FC-25, diameter 50mm, thickness 20mm) with sandpaper (manufactured by Sankyo Rikagaku Co., Ltd .: 100->180->320->600->1000-> 1500) did. 0.3 mL of the various cleaning solutions shown in Tables 1 to 3 were applied to the test piece, and left for 4 days in a constant temperature and humidity chamber with a relative humidity of 35 ° C. and a relative humidity of 60%. The cells were prepared, and the number of cells was counted visually. The rust occurrence rate was calculated according to the following formula.
Rust generation rate (%) = (Number of cells with rust) / (Number of cells on the cast iron surface) × 100
FIG. 1 is a schematic view of a test piece in which rust (black portion in the figure) has occurred, and FIG. 2 is a top view of FIG. The rust generation rate was calculated according to the above formula, divided by squares (20 × 20).

Examples 1-7, Comparative Examples 1-21
The composition of the cleaning liquid and the test results are shown in Tables 1-3.

  In Examples 1 to 7 in which a mixture of three kinds of monoester, diester, and triester of glyceryl oleate was added, rusting could be completely suppressed. However, Comparative Examples 1-15 added with other surfactants could not completely suppress rusting. Setting the rust occurrence rate to 0% is difficult.

  Table 3 is a comparison of the rust prevention ability of the cleaning liquids to which the glyceryl oleate mixture was added. With one or two glyceryl oleates, rusting could not be completely suppressed.

Claims (5)

A cleaning solution comprising a mixture of three kinds of monoester, diester, and triester of fatty acid glyceryl and dimethyl sulfoxide. The cleaning liquid according to claim 1, wherein the fatty acid glyceryl is glyceryl monooleate, glyceryl dioleate, or glyceryl trioleate. General formula

The washing | cleaning liquid of Claim 1 or 2 containing the amine represented by (In formula, R represents the C7-C13 aralkyl group which may have a substitution machine.). General formula

A benzylamine derivative represented by the formula: wherein R ₁ is hydrogen, hydroxyl group, tert-butyl group, methyl group, or methoxy group, and R ₂ is hydrogen, methyl group, or methoxy group. 3. The cleaning liquid according to 3. The cleaning liquid according to claim 1, wherein the mold is cleaned.

Images