JP5827814B2 - Deodorant composition and foundry sand - Google Patents

Description

  The present invention relates to a deodorizing composition effective for removing and reducing unpleasant odor generated from foundry sand and the like during casting production, and the foundry sand having less unpleasant odor.

More specifically, unpleasant problems caused by amines such as trimethylamine, dimethylamine and hexamethylenetetramine used as a binder and a curing agent for casting sand during casting, aldehydes such as formaldehyde, and phenols. Odors, especially deodorant compositions that can reduce or reduce unpleasant odors caused by basic gases such as ammonia and trimethylamine with low odor threshold, formaldehyde, phenols, etc., and prevent or improve the working environment, and generation of the unpleasant odors This is related to sand for casting with a low content.
The present invention also relates to a deodorizing composition that plays a role of deodorizing and neutralizing the gas mixed when exhausting gas generated in a factory and is effective as a countermeasure against odor.

  Conventionally, various production methods such as an RCS method, a CB method, an AP method, an MDI method, and a furan method are known as methods for producing a casting. If a typical RCS method is described as an example, in the production of castings, a binder such as a novolac-type phenol resin, a curing agent such as hexamethylenetetramine, a calcium stearate, etc. Foundry sand made by coating or adhering lubricant and other additives is widely used.

In the RCS method, a resin-coated type of casting sand in which a fire-resistant aggregate (silica sand) preheated to 120 to 170 ° C., a novolac type phenol resin, hexamethylenetetramine, and the like are mixed and the resin is coated on the sand. Sand (RCS) is used. When a mold is formed using this RCS, the shell mold method is heated to 250 to 350 ° C. and thermally cured in the mold. In the cold box method, a toxic triethylamine gas is added to the mold as a catalyst in order to instantaneously cure the mold near room temperature.
In these steps, unreacted phenol, hexamethylenetetramine, triethylamine (0.0054 ppm) in the resin, ammonia (0.59 ppm), trimethylamine (0. In order to exacerbate the working environment by irritating unpleasant odors caused by amines such as 0014ppm) and formaldehyde (1.9ppm), various preventive measures have been taken in addition to conventional installation of exhaust ducts, etc. It is taken.

For example, a method using a resol-type phenol resin that exhibits thermosetting properties even when using only a small amount of hexamethylenetetramine as a curing agent can provide a deodorizing effect to a certain extent, but the effect is still unsatisfactory. It is not enough and there is room for further improvement.
Further, deodorizing agent for RCS mainly composed of orange oil, turpentine oil and cedarwood oil disclosed in Patent Document 1 as a deodorizing agent capable of reducing odor by neutralizing odor and reducing odor. In addition, the fragrance-based deodorant containing α, β-unsaturated ketone and α, β-unsaturated aldehyde disclosed in Patent Document 2 and Patent Document 3 has a certain deodorizing effect. The principle is based on the masking effect of malodorous substances by fragrances and is not a fundamental solution.

  Further, triethylamine used as a catalyst in the casting molding process is discharged from the mold together with other basic gases after the action, but it is not environmentally preferable to release it into the atmosphere through an exhaust duct or the like, which is not preferable in the exhaust gas treatment device. It must be recovered and odorless before being released into the atmosphere. Examples of the exhaust gas treatment apparatus include a cleaning tower and a scrubber. It is common to absorb basic gas such as amine by filling water or acidic aqueous solution such as phosphoric acid aqueous solution and sulfuric acid aqueous solution, but the odor is weakened even if water absorbs basic gas, but completely It cannot be deodorized, and if an acidic aqueous solution such as phosphoric acid aqueous solution is used, the basic gas is absorbed by the neutralization reaction and an effective deodorizing effect is recognized to some extent. At present, disposal must be entrusted to a specialist.

JP-A-9-38748 JP 2002-210538 A JP 2004-51652 A

  The present invention has been made to prevent and improve the deterioration of the working environment and the surrounding environment due to unpleasant odors that occur in the casting manufacturing process and are contained in the exhaust gas. An object of the present invention is to provide an effective deodorant composition for removing and reducing basic gases such as ammonia and trimethylamine having a low odor threshold, and irritating odors such as formaldehyde and phenols. The second purpose is to use this deodorant composition having a small environmental load as a substitute for the phosphoric acid treatment by using it in a cleaning tower or a scrubber.

  The inventors of the present invention, as a result of earnestly examining from the viewpoint of deodorant and phosphoric acid substitution, particularly about the reduction and reduction of malodor caused by basic gases such as ammonia and trimethylamine, formaldehyde and phenols, etc. The present inventors have found that a deodorant composition containing alum is effective in solving the above problems, and have completed the present invention.

That is, this invention was made | formed based on this knowledge, and the deodorizing composition of this invention is aqueous | water-based containing 20-50 mass% of hydroxy acids and 0.1-10 mass% of alum as described in Claim 1. A deodorizing composition comprising a solution , wherein the hydroxy acid is one or two selected from malic acid and citric acid, and the alum is one or two selected from sodium alum, potassium alum, and ammonium alum It is the above .
Moreover, deodorant compositions of the second aspect, Oite deodorant composition of claim 1, wherein said deodorant composition is used for a removal reduction of unpleasant odors generated during casting the casting Features.
Also, foundry sand of the present invention, as claimed in claim 3, characterized by comprising moistened with deodorant composition according to claim 1 or 2.

According to the deodorant composition of the present invention, it depends on the production process (kneading process) of a mold material such as sand for casting and the mold material (the production method is RCS method, CB method, AP method, MDI method, furan method, etc.). The bad odor caused by amine, formaldehyde and the like generated in the molding of the mold can be greatly reduced.
Moreover, it can be made to react with unpleasant odor gas, such as amines and aldehydes discharged | emitted from a work site by using for exhaust gas processing apparatuses, such as a neutralization tank and a scrubber. Furthermore, the treatment liquid after reaction with amine gas or the like is low in toxicity, and the disposal thereof can be expected to adopt a method in accordance with the regulations set by the local government. From the above, it is possible to prevent or improve the deterioration of the working environment, and further contribute to the improvement of the surrounding environment such as air and drainage.
Furthermore, the deodorant composition of the present invention is not limited to application to casting materials as described above. For example, the deodorizing composition is diluted with water to an appropriate magnification to impregnate casting or spraying on casting-related materials, equipment, and work space. It can be applied to fields that require the same deodorizing effect, such as spraying at the factory or spraying at the factory outlet.

Next, an embodiment of the deodorant composition of the present invention will be described.
The deodorizing composition according to the present invention comprises an aqueous solution containing 20 to 50 % by mass of hydroxy acid and 0.1 to 10% by mass of alum.
Examples of the hydroxy acid include lactic acid, glycolic acid, malic acid, citric acid, tartaric acid, gluconic acid, serine, and threonine. These may be used alone or in combination of two or more.
Examples of alum include sodium alum, potassium alum, ammonium alum, iron alum, iron ammonium alum and the like. These may be used alone or in combination of two or more.
Further, these hydroxy acid and alum are dissolved in ion exchange water or the like and used as an aqueous solution.

The reason why the mixing ratio of the hydroxy acid and alum is the ratio is as follows.
This is because if the hydroxy acid is less than 10% by mass, a sufficient deodorizing effect cannot be obtained, and if it exceeds 70% by mass, the solubility in water used as a solvent is not sufficient. From the said viewpoint, it was set as 20-50 mass% .
Further, if the alum is less than 0.1% by mass, it is difficult to obtain a sufficient effect, and if it exceeds 10% by mass, the deodorizing effect is improved, but considering that it is a substance stipulated by the Labor Safety Law, the maximum is 10%. It is about%. From the said viewpoint, Preferably it is 0.5-2 mass%.
Moreover, you may add various antibacterial agents and antifungal agents as needed.

  The method for preparing the deodorant composition according to the present invention includes, for example, simultaneously adding a mixture of a hydroxy acid component and an alum component to clear water such as ion-exchanged water, and stirring until completely dissolved, or first The hydroxy acid component is added and completely dissolved, then the alum component is added and completely dissolved, and the finished deodorant composition remains unchanged.

  The deodorant composition of the present invention may be used as a casting deodorant in an aqueous solution, may be used as a substitute for a conventional phosphoric acid solution, or is contained in casting sand. Alternatively, it may be configured as foundry sand. Thus, when it comprises as sand for castings, since it is not necessary to prepare a deodorizer separately, it becomes convenient.

<Experimental example 1>
Next, the present invention will be described in more detail with reference to experimental examples of Reference Examples 1 to 4, Examples 1 to 4 and Comparative Examples 1 and 2, but the present invention is not limited to these examples.
In Experimental Example 1 and Experimental Example 2, the functions and effects of the deodorant compositions of Reference Examples, Examples and Comparative Examples prepared as described in detail below as deodorants and phosphoric acid substitutes are as follows. It was supposed to be confirmed.

(1) Odor sensory test (a) When manufacturing RCS, and (b) Blowing RCS into a mold controlled to 250 ° C., then molding the molded body for 60 seconds and opening the mold (shell mold (C) The odor when used in the cleaning tower was evaluated by sensory evaluation based on the following evaluation method and evaluation criteria.
(I) Evaluation method Under the conditions of a temperature of 20 ° C. and a relative humidity of 60%, odor panelists of 15 persons (including 5 women) performed sensory evaluation, and the superiority or inferiority was evaluated based on the average level of the obtained sensory evaluation levels. In addition, it means that a deodorizing effect is so high that this level is high.
(Ii) Evaluation criteria Level 4: An irritating odor is hardly felt.
Level 3: Irritating odor is slightly felt, but there is no practical problem.
Level 2: The pungent odor is somewhat strong.
Level 1: The pungent odor feels very strong.

(2) Odor concentration measurement (i) About RCS immediately after completion, the sample which added the deodorant composition and the sample which is not added were weighed, and amine odor concentration was measured using the detector tube. Further, after heating to 250 ° C. using this RCS, the concentration of the generated amine gas was also measured using a detector tube.
(Ii) When the deodorant composition was used for the washing tower, the treatment liquid after absorbing the basic gas for a certain period of time was weighed, and the amine odor concentration was measured using a detector tube.

(Reference Example 1)
It is composed of 5000 g of silica sand preheated to about 140 to 150 ° C. and 125 g of novolac type phenolic resin in a speed mixer, kneaded for 50 seconds, and preliminarily composed of 18.8 g of hexamethylenetetramine in 125 g of cooling water and the components shown in Table 1. Add the entire amount of curing agent aqueous solution prepared by mixing 15 g of deodorant I, cool by blowing until the formed soul-like material becomes granular, finally add 5 gr of calcium stearate, mix for 15 seconds and mix with RCS Got. Thereafter, as described above, an odor sensory test and an odor concentration measurement were performed. The results are shown in Table 9.

(Reference Examples 2 to 4)
Three types of RCS were obtained in the same manner as in Reference Example 1 except that the deodorant I of Reference Example 1 was changed to Deodorants II to IV having the component configurations shown in Tables 2 to 4, respectively. Thereafter, as described above, an odor sensory test and an odor concentration measurement were performed. The results are shown in Table 9.

(Examples 1-4)
Four types of RCS were obtained in the same manner as in Reference Example 1 except that Deodorant I of Reference Example 1 was changed to Deodorants V to VIII having the component configurations shown in Tables 5 to 8, respectively. Thereafter, as described above, an odor sensory test and an odor concentration measurement were performed. The results are shown in Table 9.

(Comparative Example 1)
In Reference Example 1, RCS was obtained in the same manner as Reference Example 1 except that the deodorant I shown in Table 1 was not used. Thereafter, as described above, an odor sensory test and an odor concentration measurement were performed. The results are shown in Table 9.

(Comparative Example 2)
In Reference Example 1, RCS was obtained in the same manner as Reference Example 1 except that the deodorant I shown in Table 1 was changed to a commercially available neutralized deodorant made of natural vegetable essential oil. Thereafter, as described above, an odor sensory test and an odor concentration measurement were performed. The results are shown in Table 9.

  As is apparent from Table 9, when the deodorant composition according to the present invention is used, the casting has an odor compared to Reference Examples 1 to 4 and Comparative Examples 1 and 2 both during kneading and when molding the mold. Both the sensory test and odor concentration measurement showed excellent results, confirming that the odor was reduced.

<Experimental example 2>
(Reference Examples 1 to 4 and Examples 1 to 4)
20 kg of the deodorizers I to VIII of Reference Examples 1 to 4 and Examples 1 to 4 shown in Tables 1 to 8 were prepared and set on a washing tower. An odor sensory test and an odor concentration measurement were performed after absorbing the amine gas discharged for a certain period of time. The results are shown in Table 10.

(Comparative Example 3)
A washing tower was set in the same manner as described above except that it was changed to water without using a deodorant. An odor sensory test and an odor concentration measurement were performed after absorbing the amine gas discharged for a certain period of time. The results are shown in Table 10.

(Comparative Example 4)
It replaced with the said deodorizer, and it set to the washing tower like the above except having changed the deodorizer into 75% -phosphoric acid aqueous solution. An odor sensory test and an odor concentration measurement were performed after absorbing the amine gas discharged for a certain period of time. The results are shown in Table 10.

  As is clear from Table 10, when the deodorant composition according to the present invention is used in the neutralization tank, compared with Reference Examples 1 to 4 and Comparative Examples 1 and 2, both in the odor sensory test and the odor concentration measurement. An excellent result was shown, and it was confirmed that the odor was reduced.

<Experimental example 3>
About the deodorizer V of the Example, and the neutralized deodorizer of the said commercial item, the deodorizing effect confirmation test in a short time was done using ion-exchange water as a control | contrast. The results are shown in Table 11.
The odor effect confirmation test was performed as follows.
Put a magnetic stirring bar in a 3 liter odor bag used for measurement. Triethylamine used as the target gas was filled with headspace odor and filled with air. The density at this time was defined as the initial density. After adding a deodorant and stirring on a magnetic stirrer for a predetermined time, the odor concentration was measured using a gas detector tube. For the deodorant evaluation, amine detector tube No. 180, no. 180L was used.

  As is clear from Table 11, it was confirmed that the deodorizing composition of the present invention showed a deodorizing effect in a short time compared to a commercially available neutralized deodorant.

<Experimental example 4>
The deodorant of Example V and 75% phosphoric acid were each diluted 50 times, and the concentration measurement over time was performed for amine gas absorption. The results are shown in Table 12 together with the deodorization rate.
The concentration measurement was performed as follows.
The measurement used a 3 liter airbag. Triethylamine used as the target gas was filled with headspace odor and filled with air. The density at this time was defined as the initial density. The deodorant was added and after a predetermined time, the odor concentration was measured using a gas detector tube. For the deodorant evaluation, amine detector tube No. 180, no. 180L was used.

  As can be seen from Table 12, it was confirmed that the deodorant composition of the present invention can neutralize amine gas in a shorter time than the conventional aqueous phosphoric acid solution.

  The deodorant composition of the present invention is useful industrially because it can provide a deodorant effective in reducing the removal of unpleasant odors and the like generated from foundry sand during casting production and the foundry sand with less unpleasant odor. is there.

Claims (3)

A deodorizing composition comprising an aqueous solution containing 20 to 50% by weight of hydroxy acid and 0.1 to 10% by weight of alum , wherein the hydroxy acid is one or two selected from malic acid and citric acid The deodorant composition, wherein the alum is one or more selected from sodium alum, potassium alum, and ammonium alum . 2. The deodorant composition according to claim 1, wherein the deodorant composition is used for removing reduction of odor generated during casting production. Foundry sand comprising the deodorant composition according to claim 1 or 2 .