JP3110550B2 - Deodorizing method in cold box molding and deodorant used for it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing method in cold box molding and a deodorizing agent used therefor.

[0002]

2. Description of the Related Art At the time of casting, a casting sand mold such as a core is sometimes used, and a so-called cold box method is sometimes used to mold this kind of sand mold. In this method, a molding die in which an upper mold and a lower mold are brought into contact with each other is filled with molding sand coated with a binder resin, and a curing agent (curing gas) for curing the binder resin is formed. The casting sand mold is molded by being introduced into the mold and hardening the above-mentioned molding sand, and there is an actual benefit that the sand mold is completed in a short time at room temperature, so that the casting operation is shortened.

By the way, triethylamine is generally used as a curing gas used in this type of cold box method. However, since triethylamine emits a bad smell, it is required to remove as much as possible. ing.

[0004] In order to respond to such a demand, for example, Japanese Patent Application Laid-Open No. 61-9945 discloses that a curing gas introduced into a molding die is guided to a neutralization tank, and the hardening gas is stored in the neutralization tank with a phosphoric acid solution. An arrangement for summing and deodorizing is shown. According to this,
Since the used curing gas is neutralized in the neutralization tank without being released to the atmosphere, it is expected to have a certain effect in preventing the generation of off-flavor.

[0005]

However, the prior art described in the above publication still has the following problems to be solved.

That is, after the sand mold is formed, the mold is opened and the sand mold is taken out. In this case, the hardening gas remaining in the sand mold after the molding is completely removed by simply sucking. The hardening gas that cannot be removed and is left inside the sand mold after the mold is opened is gradually dissipated, so that the surroundings have an unpleasant odor.

The present invention relates to a cold box molding method in which molding sand and a binder resin are filled in a molding die, and a curing agent for curing the binder resin is introduced into the molding die. It is intended to improve the deodorizing effect of the curing agent.

[0008]

That is, in the deodorization method in the cold box molding according to the invention of claim 1 of the present application (hereinafter referred to as the first invention), the molding sand is filled with molding sand and a binder resin. In addition, in the cold box molding so as to introduce a curing agent for curing the binder resin in the molding die, after introducing the curing agent into the molding die filled with molding sand, The method is characterized in that ethanol having an affinity is brought into contact with molding sand after molding, and a neutralizing agent is brought into contact with the above-mentioned curing agent.

The deodorizing method in the cold box molding according to the invention of claim 2 of the present application (hereinafter referred to as the second invention) is a method according to the first invention, wherein a curing agent is added to a molding die filled with molding sand. After the introduction, ethanol is introduced into the mold, and the mold is scavenged and brought into contact with a neutralizing agent.

The invention of claim 3 of the present application (hereinafter referred to as “third invention”)
The deodorization method in the cold box molding according to the invention is characterized in that, in the configuration of the first invention, after a curing agent is introduced into a molding die filled with molding sand, a mixture of a neutralizing agent and ethanol is added to the molding die. It is characterized by being introduced.

Further, in the deodorization method in the cold box molding according to the invention of claim 4 of the present application (hereinafter referred to as a fourth invention), the molding sand is filled with molding sand and a binder resin, and the molding die is In the cold box molding was to introduce a curing agent for curing the binder resin in the,
Pre-mixed with the casting sand and a neutralizing agent to neutralize the hardener,
After filling the mixture into a mold, a curing agent is introduced into the mold, and then ethanol having an affinity for the curing agent is introduced into the mold.

On the other hand, the invention of claim 5 of the present application (hereinafter referred to as the fifth invention)
The deodorizing agent used in the deodorizing method in the cold box molding according to the invention is a neutralizing agent for neutralizing a curing agent for curing the binder resin, and ethanol having an affinity for both the neutralizing agent and the curing agent. And characterized in that:

[0013]

According to the above arrangement, in any of the first to third aspects of the present invention, ethanol having a high affinity for the hardener is brought into contact with the molding sand after being brought into contact with the hardener. Also, the curing agent remaining in the sand mold after molding is dissolved in ethanol and deodorized in a short time.
Since the curing agent dissolved in ethanol is deodorized by the neutralization reaction with the neutralizing agent, the deodorizing effect is improved as compared with the related art.

In particular, according to the deodorizing method according to the second invention, ethanol is introduced into the mold before removing the sand mold from the mold, so that the ethanol easily comes into contact with the curing agent and the deodorizing effect is obtained. Will be further improved.

Further, according to the deodorizing method of the third invention, a mixture of ethanol and a neutralizing agent is introduced into the mold before removing the sand mold from the mold. Since the curing agent is neutralized and deodorized, the deodorizing effect is further improved.

Further, according to the deodorizing method according to the fourth invention,
By adding the neutralizing agent to the foundry sand in advance, the neutralizing agent will also be present inside the sand mold after molding,
The reaction rate of the neutralization reaction is improved. In addition, since the neutralization reaction proceeds in a state where the curing agent is dissolved in ethanol, the reaction rate is further improved.

On the other hand, according to the fifth invention, a deodorizing agent is constituted by a neutralizing agent for neutralizing a curing agent for curing the binder resin, and ethanol which is compatible with both the neutralizing agent and the curing agent. As a result, the curing agent is reliably removed in a state dissolved in ethanol, and a high deodorizing effect is obtained because the neutralization reaction with the neutralizing agent is performed in a state dissolved in ethanol. Also.

[0018]

Embodiments of the present invention will be described below.

FIG. 1 shows a sand mold manufacturing system in which the method of the present invention is carried out. A lid 2 and a bottom 3 provided in a molding apparatus 1 are formed by an upper mold 4a and a lower mold 4b. Type 4
Is detachably attached to the upper mold 4a.
A gas supply pipe 6 is interposed between the lid 2 supporting the first tank and the first tank 5 filled with triethylamine gas as a curing agent. A first valve 7 for controlling a gas flow rate is provided at an intermediate portion of the gas supply pipe 6, and the first valve 7 is supplied with pressurized air generated by a first pressure pump 8 through a first air supply pipe. 9. A part of the pressurized air is introduced into the bottom of the first tank 5 through a branch pipe 10 branched from the first air supply pipe 9. Therefore, the triethylamine gas filled in the first tank 5 is supplied under pressure to the mold 4 via the gas supply pipe 6.

The lid 2 has nozzles 11a, which open toward the blow ports 4c, 4c formed in the upper mold 4a.
A multipoint atomizing injector 11 having 11a is built in, and one end of a deodorant supply pipe 12 is connected to the multipoint atomizing injector 11. The other end of the deodorant supply pipe 12 extends downward through an upper wall of the second tank 14 in which ethanol 13 constituting the deodorant is stored.

On the other hand, the multipoint atomizing injector 11
A second air supply pipe 16 is interposed between the second pressurizing pump 15 and the second pressurizing pump 15 to pressurize the pressurized air generated by the second pressurizing pump 15. A part of the pressurized air is introduced into the upper portion of the second tank 14 via a branch pipe 17 branched from the second air supply pipe 16. The branch pipe 17 is provided with a second valve 18 for controlling the flow rate of the pressurized air supplied to the second tank 14. Therefore, by opening the second valve 18 and introducing the pressurized air into the second tank 14, the ethanol 13 stored in the second tank 14 passes through the deodorant supply pipe 12 to the multipoint atomizing injector 11. It is fed into the molding die 4 in a state of being atomized by pressurized air which is fed under pressure and further sent through the second air feed pipe 16. Further, by closing the second valve 18 and stopping the introduction of the pressurized air, the molding is performed by the pressurized air supplied to the multipoint atomizing injector 11 through the second air supply pipe 16. The inside of the mold 4 will be scavenged.

One end of an exhaust pipe 19 is connected to the bottom body 3 supporting the lower mold 4b, and the other end of the exhaust pipe 19 penetrates a filter 20 to store phosphoric acid water 21. And extends to the bottom of the neutralization tank 22.

Note that local exhaust devices 23 and 24 are disposed above the neutralization tank 22 and the mold 4.

In such a system configuration, in the first embodiment of the present invention, a sand mold is manufactured through the processing steps shown in the flowchart of FIG. That is, first, in step S1, a coated sand 25 coated with a binder resin made of, for example, a urethane-based resin is filled in the molding die 4, but in this embodiment, as shown in FIG. Blow holes 26a, 26a formed in the bottom surface of sand tank 26 in which coated sand 25 is stored, and upper mold 4
The coated sand 25 is set so that the blow ports 4c, 4c formed on the side a face each other, and compressed air is supplied to the sand tank 26, whereby the coated sand 25 is injected under pressure into the cavity 4d formed in the mold 4. It has become.

Then, as shown in FIG. 1, the mold 4 filled with the coated sand 25 is set between the lid 2 and the bottom 3 of the molding apparatus 1, and then the step S2 of the above flow chart is executed. Then, triethylamine gas is injected into the mold 4 under pressure. That is, by operating the first pressurizing pump 8 to supply pressurized air to the bottom of the first tank 5 and the first valve 7, the triethylamine gas filled in the first tank 5 is turned into a solid arrow. As shown in the figure, the binder resin coated on the coated sand 25 is cured by being injected into the molding die 4 from the upper die 4a through the gas supply pipe 6 and the lid 2 of the molding device 1, and also molded. Exhaust gas containing unreacted triethylamine discharged to the bottom 3 through the mold 4 is guided to the neutralization tank 22 through the exhaust pipe 19.

Next, step S in the above flow chart
Steps S3 to S5 are executed, the ethanol 13 is atomized and injected into the mold 4, and then the mold 4 is scavenged in a state where the injection of the ethanol 13 is stopped, and triethylamine contained in the exhaust gas is removed from the neutralization tank. It will be neutralized at 22.

That is, by operating the second pressurizing pump 15 with the second valve 18 opened, pressurized air is supplied to the second tank 14 and the multipoint atomizing injector 11 respectively. As shown by the dashed line in the figure, the ethanol 13 flows into the mold 4 via the multipoint atomizing injector 11 in an atomized state. Then, by closing the second valve 18, the supply of the ethanol 13 is stopped,
Multipoint atomizing injector 1 via second air supply pipe 16
Scavenging of the mold 4 is performed by the pressurized air discharged from 1, and exhaust gas containing ethanol remaining in the mold 4 flows into the neutralization tank 22 via the exhaust pipe 19. In this case, the triethylamine left inside the sand mold 26 is dissolved in the ethanol 13 and is removed in a short time.

Then, by removing the mold 4,
As shown in FIG. 4, the upper mold 4a and the lower mold 4b are separated and the sand mold 26 is taken out.

Next, a second embodiment of the present invention will be described.
In this embodiment, a fumaric acid ethanol solution 27 in which fumaric acid constituting a deodorant is dissolved in ethanol together with ethanol is stored in the second tank 14 in FIG. The fumaric acid ethanol solution 27
For example, 1 gr for 100 cc of ethanol
A saturated solution in which fumaric acid is dissolved is used.

In this case, the sand mold is manufactured through the processing steps shown in the flowchart of FIG.

That is, also in this case, after the coated sand 25 previously coated with the binder resin is injected into the molding die 4, triethylamine gas is injected into the molding die 4 (steps T1 and T2). Then, the fumaric acid ethanol solution 27 is atomized and injected into the mold 4, and after a lapse of a predetermined time, the fumaric acid ethanol solution 2
7 with the injection stopped (step T
3, T4).

In this case, before removing the sand mold 26 from the mold 4, the ethanol solution 27 of fumaric acid is added to the mold 4.
Therefore, the triethylamine dissolved in the ethanol solution 27 of fumaric acid causes an acid-base neutralization reaction with fumaric acid to deodorize.
In this case, as a neutralizing agent, a dibasic acid such as malonic acid or maleic acid may be used in addition to fumaric acid.

Then, the exhaust gas scavenged from the molding die 4 is guided to the neutralization tank 22 to be further neutralized.

In this case, as shown in FIG. 6, a gas detecting tube 28 (No.
When the odor was measured by approaching 180), triethylamine was not detected at all, and the effectiveness of using ethanol and fumaric acid as deodorants was confirmed.

Incidentally, the fumaric acid ethanol solution 27 may be directly sprayed on the sand mold 26 after the mold is opened. In this case, since the spraying operation is performed in the open space, it is necessary to spray a large amount of the fumaric acid ethanol solution 27, but there is an advantage that the system configuration is simplified.

Next, a third embodiment of the present invention will be described with reference to the flowchart of FIG.

In the third embodiment, first, fumaric acid is previously mixed into the coated sand 25 in step U1. That is, as shown in FIG. 8, a predetermined amount of fumaric acid powder 30 is mixed and uniformly mixed while stirring the coated sand 25 placed in the stirring vessel 29. And
After injecting this fumaric acid mixed coated sand 25 ^′ into the mold 4, it is set in the molding apparatus 1 shown in FIG. 1 and triethylamine is injected and cured (steps U 2, U 2).
3). Then, after the ethanol 13 stored in the second tank 14 is atomized and injected into the mold 4, the supply of the ethanol 13 is stopped and the mold 4 is scavenged (Steps U3 and U4).

According to this method, by adding the fumaric acid powder 30 to the coated sand 25 in advance, fumaric acid is also present inside the sand mold 26 after molding, and the neutralization reaction is performed. Speed will be improved. In addition, since the neutralization reaction proceeds in a state in which triethylamine is dissolved in ethanol 13, triethylamine is deodorized in a very short time.

Next, the results of an experiment performed to determine the amount of fumaric acid added to the amount of amine used will be described. As shown in FIG. ), No addition, the amount of fumaric acid was 0.1 gr, 0.5 gr, 1.0 g
Three test pieces 31 each having r, 1.5 gr, and 2.0 gr were produced. After spraying ethanol on each test piece 31 and removing the ethanol by suction, each test piece 3
The gas detection tube 28 was arranged at a position 10 cm above the sample No. 1 and the odor was measured. At the same time, sensory evaluation was conducted by five panelists. In addition, as for the sensory evaluation, as shown in Table 1 below, individual differences among panelists were absorbed by averaging odor intensities based on indexes quantified in six steps.

[0040]

[Table 1] The results of the experiment are shown in Table 2 below.

[0041]

[Table 2] In conclusion, it was found that the addition amount was required to be two to three times the weight of the amine used. Therefore, in consideration of other uncertain factors, it is actually desirable to further increase the amount of fumaric acid.

[0042]

As described above, in any of the first to third inventions, ethanol having a high affinity for the hardener is brought into contact with the molding sand after being brought into contact with the hardener. The hardener remaining in the sand mold after molding is also dissolved in ethanol and deodorized in a short time.
Since the curing agent dissolved in ethanol is deodorized by the neutralization reaction with the neutralizing agent, the deodorizing effect is improved as compared with the related art.

In particular, according to the deodorizing method according to the second invention, since the ethanol is introduced into the mold before removing the sand mold from the mold, the ethanol easily comes into contact with the curing agent and the deodorizing effect is obtained. Will be further improved.

According to the deodorization method of the third invention, a mixture of ethanol and a neutralizing agent is introduced into the mold before removing the sand mold from the mold. Since the curing agent is neutralized and deodorized, the deodorizing effect is further improved.

Further, according to the deodorizing method according to the fourth invention,
By adding the neutralizing agent to the foundry sand in advance, the neutralizing agent will also be present inside the sand mold after molding,
The reaction rate of the neutralization reaction is improved. In addition, since the neutralization reaction proceeds in a state where the curing agent is dissolved in ethanol, the reaction rate is further improved.

On the other hand, according to the fifth invention, a deodorizing agent is constituted by a neutralizing agent for neutralizing a curing agent for curing the binder resin, and ethanol which is compatible with both the neutralizing agent and the curing agent. As a result, the curing agent is reliably removed in a state dissolved in ethanol, and a high deodorizing effect is obtained because the neutralization reaction with the neutralizing agent is performed in a state dissolved in ethanol. Also.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a sand mold manufacturing system.

FIG. 2 is a flowchart showing a sand mold manufacturing process in the first embodiment.

FIG. 3 is a schematic view showing an operation of injecting coated sand into a molding die.

FIG. 4 is a schematic view showing a state after the mold is opened.

FIG. 5 is a flowchart showing a sand mold manufacturing process in a second embodiment.

FIG. 6 is a schematic diagram showing a measurement state of odor of a sand mold after molding.

FIG. 7 is a flowchart showing a sand mold manufacturing process in a third embodiment.

FIG. 8 is a schematic view showing a process of mixing fumaric acid powder into a coated sand.

FIG. 9 is a schematic diagram showing an odor measurement method performed for determining fumaric acid with respect to the amount of amine used.

[Explanation of symbols]

Reference Signs List 4 Mold 13 Ethanol 21 Phosphoric acid water 25 Coated sand 25 ^' Fumaric acid mixed coated sand 27 Fumaric acid ethanol solution 30 Fumaric acid powder

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshitaka Takahashi 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) B22C 5/00 -25/00 B01D 53 / 34,53 / 72,53 / 81

Claims (5)

(57) [Claims] 1. A deodorizing method in a cold box molding method in which molding sand and a binder resin are filled in a mold and a curing agent for curing the binder resin is introduced into the mold. Then, after introducing the hardening agent into the molding die filled with the molding sand, the ethanol having affinity for the hardening agent is brought into contact with the molding sand after molding, and the neutralizing agent is brought into contact with the hardening agent. A deodorizing method in cold box molding. 2. After introducing a curing agent into a mold filled with molding sand, ethanol is introduced into the mold,
2. The deodorizing method according to claim 1, wherein the mold is scavenged and brought into contact with a neutralizing agent. 3. The cold box according to claim 1, wherein a hardening agent is introduced into a mold filled with molding sand, and then a mixture of a neutralizing agent and ethanol is introduced into the mold. Deodorizing method in molding. 4. A deodorizing method in a cold box molding method in which molding sand and a binder resin are filled in a mold and a curing agent for curing the binder resin is introduced into the mold. A casting sand and a neutralizing agent for neutralizing the hardener are preliminarily mixed, and the mixture is filled in a mold, and then the hardener is introduced into the mold. A deodorizing method in cold box molding, comprising introducing ethanol having affinity into a mold. 5. A deodorization method for use in a deodorization method in cold box molding, in which molding sand and an adhesive resin are filled in a molding die and a curing agent for curing the adhesive resin is introduced into the molding die. Cold box molding, wherein the deodorizing agent comprises a neutralizing agent for neutralizing the curing agent, and ethanol having an affinity for both the neutralizing agent and the curing agent. Deodorant used in the deodorization method in Japan.