JP6907259B2 - Release agent composition for die casting and its manufacturing method - Google Patents

Description

The present application relates to a die casting mold release agent composition used for producing a die casting molded product containing an aluminum alloy, a magnesium alloy, etc. and a method for producing the same. Regarding the method.

Usually, when a die-cast molded product containing an aluminum alloy, a magnesium alloy, or the like is produced, a mold release agent for die casting is applied to a mold in order to impart mold releasability. At this time, if the release agent is not properly adhered to the mold, problems such as seizure occur, which adversely affects the quality of the die-cast molded product. Therefore, it is an important issue to know the adhesion state of the release agent sprayed on the mold.

Regarding this, Patent Document 1 discloses a die casting mold release agent characterized by containing a photopigment as a color former, and further, when the mold release agent is sprayed on a heated mold and irradiated with black light. It is described that the adhesion state of the release agent is visually confirmed from the light emission.
Patent Document 2 discloses a lubricating film forming agent containing an aqueous fluorescent dye in a coating type aqueous lubricating film forming agent for metal plastic working, which contains an aqueous base component and optionally a lubricating component. ing.

Japanese Unexamined Patent Publication No. 2006-68751 Japanese Unexamined Patent Publication No. 2007-277468

As described in the first embodiment, the mold release agent for die casting of Patent Document 1 can barely confirm the light emission when the mold release agent containing the color former is used in a mold at 250 ° C. There is a risk that the color former may be thermally decomposed and the fluorescent activity may be deactivated.
Since the water-based fluorescent coating material of Patent Document 2 is "water-based", its solubility in a silicone compound is very low. Therefore, when the mold release agent is attached to the mold, there is a possibility that the adhesion state of the silicone compound and the adhesion state of the fluorescent paint do not correlate.

Therefore, as a result of diligent studies to solve the above problems, the inventors have found a fluorescent agent that is appropriately soluble in a silicone compound and has high heat resistance to high temperatures, and completed the present invention.

That is, the present application provides one of the means for solving the above problems.
A mold release agent for die casting, which comprises a silicone compound and a fluorescent agent that emits light when irradiated with ultraviolet rays of 365 nm, the fluorescent agent has a condensed ring structure of a 6/6 member ring, and the molecular weight of the fluorescent agent is 300 or more and 600 or less. The composition is disclosed.

Here, the "6/6-membered ring-condensed structure" means a condensed ring structure (ortho-condensation structure) in which two 6-membered ring structures share two atoms and one bond, and "6 / "Having a condensed ring structure of a 6-membered ring" means having a condensed ring structure of a 6/6 membered ring in the molecular structure. That is, the fluorescent agent of the present disclosure includes not only compounds containing a 6/6-membered fused ring structure such as a naphthalene skeleton, a coumarin skeleton, and a quinoline skeleton, but also a 6/6/6-membered fused ring such as a phenanthrene skeleton. It also includes compounds containing structures and the like.

In the composition, it is preferable that the condensed ring structure of the 6/6 member ring of the fluorescent agent is a naphthalene skeleton or a coumarin skeleton.

The content of the fluorescent agent is preferably 0.1% by mass or more and 3.0% by mass or less based on the total of the silicone compound and the fluorescent agent. The content of the silicone compound is preferably 5% by mass or more and 50% by mass or less based on the entire composition.

When the composition is oily, it is preferable to further contain a hydrocarbon solvent. On the other hand, when the composition is aqueous, it is preferable to further contain a surfactant and water. When it is aqueous, it is preferable that the composition is emulsified.

Further, the present application provides one of the means for solving the above problems.
It comprises a step of dissolving a fluorescent agent that emits light by irradiation with ultraviolet rays of 365 nm into a silicone compound, the fluorescent compound has a condensed ring structure of a 6/6 member ring, and the molecular weight of the fluorescent compound is 300 or more and 600 or less. , A method for producing a mold release agent composition for die casting.

Since the fluorescent agent used in the die casting mold release composition of the present disclosure has heat resistance to high temperatures (250 ° C. or higher), the fluorescent activity is not deactivated even when the mold temperature is 250 ° C. or higher.
Further, since the fluorescent agent used in the die-casting mold release agent composition of the present disclosure is appropriately dissolved in the silicone compound, the fluorescent agent is easily dispersed uniformly in the mold release agent. Therefore, when the mold release agent is sprayed on the mold, the adhesion state of the release agent (silicone compound) in the mold and the adhesion state of the fluorescent agent are likely to correlate with each other. The adhesion state of the release agent (silicone compound) can be easily confirmed from the light emission.
Therefore, according to the die-casting mold release agent composition of the present disclosure, it is possible to easily confirm the adhered state of the mold release agent (silicone compound) in a high-temperature mold, which has been difficult in the past.

It is a figure explaining the structure of the coumarin-based fluorescent agent used in an Example. It is a figure explaining the structure of the naphthalene fluorescent agent used in an Example. It is a figure explaining the structure of other fluorescent agents used in an Example. It is a figure explaining the result of the concentration test. It is a figure explaining the result of the oil property test.

The mold release agent composition for die casting of the present disclosure contains a silicone compound and a fluorescent agent that emits light when irradiated with ultraviolet rays of 365 nm. The fluorescent agent has a condensed ring structure of a 6/6 member ring, and the molecular weight of the fluorescent agent is 300 or more and 600. It is characterized by the following.

<Silicone compound>
As the silicone compound, known silicone compounds such as silicone oil and silicone wax can be used.
Specific examples include dimethyl silicone, cyclic silicone, methylphenyl silicone, methylhydrogen silicone, and organomodified silicone compounds. The organopolysiloxane is partially or wholly modified with an alkyl group, an aralkyl group, an amino group, a carboxylalkyl group or an alkylcarboxylic acid group, a hydroxyalkyl group, an aminoalkyl group, a polyether group, or the like. And so on. These silicone compounds may be used alone or in combination of two or more.

The content of the silicone compound is more preferably 5% by mass or more and 50% by mass or less based on the entire composition. When the content of the silicone compound is in the above range, it is possible to impart appropriate releasability to the composition and prevent seizure.

<Fluorescent agent>
It is important that the fluorescent agent that can be used in the compositions of the present disclosure emits light when irradiated with ultraviolet rays at 365 nm. This makes it possible to easily confirm the adhered state of the release agent (silicone compound) from the light emission of the fluorescent agent.
The fluorescent agent of the present disclosure may be composed of a single fluorescent compound or may be composed of a plurality of fluorescent compounds. Therefore, in the following, the term "fluorescent agent" refers to a fluorescent compound when the fluorescent agent is composed of a single fluorescent compound, and refers to all of these fluorescent compounds when the fluorescent agent is composed of a plurality of fluorescent compounds.

The fluorescent agent preferably has a structure having a condensed ring structure of a 6/6 member ring. As a result, the heat resistance of the fluorescent agent can be improved, and the silicone compound can be provided with appropriate solubility.
Here, the "6/6-membered ring-condensed structure" means a condensed ring structure (ortho-condensation structure) in which two 6-membered ring structures share two atoms and one bond, and "6 / "Having a condensed ring structure of a 6-membered ring" means having a condensed ring structure of a 6/6-membered ring in the molecular structure. That is, the fluorescent agent of the present disclosure includes not only compounds containing a 6/6-membered fused ring structure such as a naphthalene skeleton, a coumarin skeleton, and a quinoline skeleton, but also a 6/6/6-membered fused ring such as a phenanthrene skeleton. It also includes compounds containing structures and the like.

However, from the viewpoint of improving the solubility in the silicone compound, it is more preferable that the fluorescent agent contains a naphthalene skeleton or a coumarin skeleton. More preferably, the naphthalene skeleton has the following structure (1), and the coumarin skeleton has the following structure (2) or (3).

R ¹ independently represents a linear or branched alkyl group having 1 to 8 carbon atoms. l, m, and n represent integers of 0 or more, and it is preferable that l + m + n ≧ 2 from the viewpoint of improving the solubility in the silicone compound. X independently represents O, S, and NR ² , and R ² is hydrogen or a linear or branched alkyl group having 1 to 4 carbon atoms.

R ³ represents hydrogen, a linear or branched alkyl group having 1 to 4 carbon atoms, a benzimidazole group, a benzoxazole group, or a benzothiazole group, and is preferably a benzothiazole group. R ⁴ represents hydrogen, straight-chain or branched alkyl group having 1 to 4 carbon atoms, benzimidazole group, benzoxazole group, or a benzothiazole group. At ^{least one of R 3} and R ⁴ is preferably a benzimidazole group, a benzoxazole group, or a benzothiazole group. This improves the heat resistance of the fluorescent agent.
Y represents an ^NR _{5 2} or OR ^{5, R 5} is a straight-chain or branched alkyl group having 1 to 8 carbon hydrogen or carbon. When R ⁵ is an alkyl group, the terminal of the alkyl group may be bonded to the 6-position or 8-position of the coumarin skeleton to form a ring structure. Having Y causes even stronger fluorescence to be emitted.

R ⁴ and Y are as described above. Z represents an alkylene group such as a methylene group, an ethylene group, a methylmethylene group, or a dimethylmethylene group, a carbonyl group, or a sulfonyl group, and is preferably a carbonyl group or a sulfonyl group. Regarding the binding position of Z, it is preferable that Y is bonded to the three positions of the two coumarin skeletons.

When comparing only the skeletal structures of the naphthalene skeleton and the coumarin skeleton, the naphthalene skeleton is preferable. Fluorescent agents with a coumarin skeleton easily develop color even under visible light, so if a mold release agent is applied to an unintended place or spilled on the floor or clothes during use, it will become a stain that is difficult to clean and the working environment will deteriorate. There is a risk of

The molecular weight of the fluorescent agent is preferably 300 or more and 600 or less. If the molecular weight of the fluorescent agent is less than 300, the heat resistance of the fluorescent agent is lowered, and when the mold release agent is sprayed on a high-temperature mold, the fluorescent agent may be thermally decomposed and the fluorescent activity may be lost. On the other hand, when the molecular weight of the fluorescent agent exceeds 600, the solubility in the silicone compound decreases. Therefore, the amount of light emitted from the fluorescent agent due to ultraviolet irradiation also decreases, and there is a risk that it will be difficult to visually confirm the light emission of the fluorescent agent.
However, when the fluorescent agent has a naphthalene skeleton, the molecular weight of the fluorescent agent is more preferably 400 or more and 520 or less, and particularly preferably 450 or more and 520 or less. When the fluorescent agent has a coumarin skeleton, the molecular weight of the fluorescent agent is more preferably 300 or more and 420 or less, and particularly preferably 350 or more and 420 or less. This improves the solubility in silicone compounds.
When the fluorescent agent is composed of a plurality of fluorescent compounds, the weighted average molecular weight calculated from the mixing ratio of these compounds is used as the molecular weight of the fluorescent agent.

The lower limit of the content of the fluorescent agent is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and 0.25% by mass based on the total of the silicone compound and the fluorescent agent. It is more preferable, and 0.5% by mass or more is particularly preferable. When the lower limit of the content of the fluorescent agent based on the total of the silicone compound and the fluorescent agent is 0.1% by mass or more, it becomes easy to confirm the light emission of the fluorescent agent. When it is 0.2% by mass or more, the light emission can be clearly confirmed, and when it is 0.5% by mass or more, the light emission can be confirmed more clearly.
On the other hand, the upper limit of the content of the fluorescent agent is preferably 3.0% by mass or less based on the total of the silicone compound and the fluorescent agent. If the content of the fluorescent agent based on the total of the silicone compound and the fluorescent agent exceeds 3.0% by mass, the emission of the fluorescent agent is saturated, which is economically disadvantageous. Further, when the composition is used in an aqueous solution, the composition becomes difficult to emulsify.

When the content of the fluorescent agent is based on the entire composition, the lower limit is preferably 0.025% by mass or more, more preferably 0.05% by mass or more, and 0.0625% by mass or more. Is more preferable, and 0.125% by mass or more is particularly preferable. When the lower limit of the content of the fluorescent agent based on the entire composition is 0.025% by mass or more, it becomes easy to confirm the light emission of the fluorescent agent. When it is 0.05% by mass or more, the light emission can be clearly confirmed, and when it is 0.125% by mass or more, the light emission can be confirmed more clearly.
On the other hand, the upper limit of the content of the fluorescent agent is preferably 3.0% by mass or less based on the entire composition.

<Release composition for die casting>
The mold release agent composition for die casting of the present disclosure may contain the above silicone compound and the above fluorescent agent. That is, the mold release agent composition for die casting may be used in an oily state or in an aqueous form.

When the die casting mold release agent of the present disclosure is used in an oily manner, it is preferable to further contain a hydrocarbon solvent.

The hydrocarbon solvent is not particularly limited, but it is preferable to use paraffins having a flash point of 70 ° C. or higher for ease of handling.
The content of the hydrocarbon solvent is not particularly limited, but the lower limit is preferably 70% by mass or more and the upper limit is preferably 95% by mass or less based on the entire composition. If the content of the hydrocarbon solvent is less than 70% by mass, the release component such as the silicone compound becomes too thick, which causes uneven adhesion. On the other hand, if the content of the hydrocarbon solvent exceeds 95% by mass, seizure may occur due to insufficient adhesion of the release component to the mold.

On the other hand, when the die casting mold release agent of the present disclosure is used in an aqueous solution, it is preferable to further contain a surfactant and water. Moreover, it is preferable that the composition is emulsified. By being emulsified, the fluorescent agent is stabilized in the micelle, and when the mold release agent is sprayed on the mold, the luminescence of the fluorescent agent is less likely to change with time (precipitation of luminescence), resulting in unevenness and variation in luminescence. Is reduced.

The type of surfactant is not particularly limited as long as the silicone compound can be emulsified stably. For example, any of anionic, cationic, amphoteric, or nonionic surfactants can be used. Among these, nonionic surfactants are preferable. Specifically, polyoxyalkylene glycol, polyoxyalkylene alkyl ether and the like are preferable.
These surfactants may be used alone or in combination of two or more.

From the viewpoint of stable emulsification of the silicone compound, the content of the surfactant preferably has a lower limit of 0.1% by mass or more, preferably 1% by mass or more, and an upper limit of 1% by mass or more based on the entire composition. It is preferably 10% by mass or less.

As the water, any of pure water, ion-exchanged water, tap water and the like can be used.

(Other additives)
As other additives, mineral oils, fats and oils, synthetic ester oils, oily agents, synthetic waxes and the like may be blended for the purpose of supplementing the lubricity of the die casting release agent composition. Moreover, various additives other than the above may be contained. Examples thereof include antifoaming agents, foaming agents, drying accelerators, corrosion inhibitors, preservatives, rust inhibitors, thickeners, antioxidants and the like.

<How to use the mold release agent composition for die casting>
The mold release agent composition for die casting of the present disclosure can be applied not only in a general amount but also in a so-called small amount application.
In recent years, the amount of mold release agent applied has been reduced for the purpose of improving productivity by shortening the cycle time and reducing the environmental load by reducing waste liquid. On the other hand, there are increasing cases where the mold release agent is used under the condition that the mold reaches a high temperature of 250 ° C. or higher, and if the amount of the mold release agent applied is reduced, the cooling effect may not be sufficiently obtained.
The mold release agent composition for die casting of the present disclosure can be applied in a small amount under such a high temperature condition. For example, in a step of applying a mold release agent to a mold via a spray nozzle, application to the mold is performed. the amount of 0.0005ml / cm ² or more, even if below 0.01 ml / cm ^2, can impart sufficient cooling performance and releasability, and also adhesion state of the release agent can be confirmed easily ..

<Manufacturing method of mold release agent composition for die casting>
As a method for producing a mold release agent composition for die casting, it is preferable to include a step of dissolving the fluorescent agent in the silicone compound.
By dissolving the fluorescent agent in the silicone compound, the fluorescent agent can be uniformly dispersed in the release agent (in the silicone compound).

Further, when producing an aqueous mold release agent composition for die casting, it is preferable to include a step of emulsifying the solution obtained by the above-mentioned dissolution step. As a result, the fluorescent agent is stabilized in the micelle, and when the mold release agent is sprayed on the mold, the luminescence of the fluorescent agent is less likely to change with time (precipitation of luminescence), and unevenness and variation in luminescence are reduced.
As the emulsifying step, a known method used for producing an aqueous mold release agent for die casting can be adopted.

Hereinafter, examples will be described, but the mold release agent for die casting of the present disclosure is not limited to this.

1 to 3 show the fluorescent agents used in the examples. The naphthalene-based fluorescent agent C is a mixture of three compounds having different numbers of substitutions of the t-butyl group (t-Bu). Specifically, the number of substitutions of t-Bu of the naphthalene-based fluorescent agent C shown in FIG. 2 is l + m + n = 2 (molecular weight: 474.6), and the number of substitutions of t-Bu is l + m + n = 3. 3 Substituents (Molecular Weight: 530.1) and 4 Substitutes (Molecular Weight: 586.8) having t-Bu substitution numbers of l + m + n = 4. The mixed ratio of these is disubstituted: tri-substituted: 4-substituted = 42.3: 45.0: 12.7, and the weighted average molecular weight of the naphthalene-based fluorescent agent C calculated from this mixed ratio is It is 514.
The viscosity of the silicone compound used in the examples was measured with a rotational viscometer according to JPI-5S-26-99.

<Heat resistance test>
The heat resistance of the fluorescent agent and the heat resistance of the release agent using the fluorescent agent were examined.

(Measurement of thermal decomposition start temperature)
In order to examine the heat resistance of the fluorescent agent itself, the thermal decomposition start temperature of the fluorescent agent was measured. The results are shown in Table 1.
The measurement conditions are as follows.
[Measurement condition]
-Device: TG-DTA (STA7200 manufactured by Hitachi High-Tech Science Corporation)
・ Sample amount: 3.0 mg
-Measurement temperature range: Room temperature to 350 ° C
・ Temperature rise rate: 20 ° C / min
・ Atmosphere: Air
-Air flow rate: 300 ml / min

(Light emission test)
The following tests were conducted to investigate the heat resistance of the release agent containing the fluorescent agent. That is, a mold release agent containing a fluorescent agent was sprayed on each of the steel sheets heated to 250 ° C. and 300 ° C., and the sprayed portion was irradiated with ultraviolet rays, and the light emission of the mold release agent was visually confirmed. Those for which light emission could not be confirmed were evaluated as "x", those for which light emission was barely confirmed were evaluated as "Δ", and those for which light emission could be clearly confirmed were evaluated as "○". The results are shown in Table 1 and the test conditions are shown in Table 2.
The release agent used in the test was prepared as follows. First, the fluorescent agent is dissolved in an organomodified silicone compound (C12 alkyl group (dodecyl group): C9 aralkyl group (2-methylphenethyl group) = 4: 1, viscosity at 25 ° C. of 1500 mPa · s), and the content of the fluorescent agent. A solution was obtained in which was 0.3% by mass (the example shown by * in Table 1 was tested at 0.1% by mass because the solubility of the fluorescent agent was low). Then, the above solution was emulsified with a surfactant (polyoxyethylene polyoxypropylene isodecyl ether (EO isodecyl ether)) and water. At this time, the contents of the fluorescent agent and the silicone compound were set to 25% by mass based on the entire release agent. The content of the surfactant was 1.5% by mass based on the entire release agent.

(result)
It was found that the fluorescent agents of Comparative Examples 1 to 3 having no 6/6 membered ring condensed ring structure had low heat resistance (pyrolysis start temperature) regardless of the molecular weight. The fluorescent agent of Comparative Example 4 had a condensed ring structure of a 6/6 member ring, but had a small molecular weight and low heat resistance. Therefore, it is probable that the release agents of Comparative Examples 1 to 4 could not be confirmed to emit light because their fluorescent activity was deactivated when they were sprayed on the high temperature mold.
On the other hand, the fluorescent agents of Examples 1 to 7 have a condensed ring structure of 6/6 membered rings and have a relatively large molecular weight, so that they have high heat resistance and are fluorescently active even when sprayed on a high-temperature mold. Was held. The result of Examples 3 and 4 at a mold temperature of 300 ° C. is “Δ”, but this does not mean that the fluorescent activity of the fluorescent agent is inactivated, and the higher the mold temperature is, the higher the mold temperature is. It is considered that this is because the amount of the release agent adhered is reduced, so that the amount of the release agent adhered to the mold release agents of Examples 3 and 4 is also small, and it is difficult to confirm the emission of the fluorescent agent. Therefore, it is considered that light emission can be confirmed by increasing the amount of the release agent to be applied in Examples 3 and 4.

<Solubility test>
The solubility of the fluorescent agent in the silicone compound was examined using organomodified silicone compounds having different viscosities. Table 3 shows the results of solubility in an organomodified silicone compound (C12 alkyl group (dodecyl group): C9 aralkyl group (2-methylphenethyl group) = 4: 1, viscosity at 25 ° C. of 900 mPa · s). The results of solubility in an organomodified silicone compound (C12 alkyl group (dodecyl group): C9 aralkyl group (2-methylphenethyl group) = 4: 1, viscosity at 25 ° C. of 1500 mPa · s) were shown. “◯” in Tables 3 and 4 indicates that the fluorescent agent was dissolved in the silicone compound and uniformly dispersed, and “x” indicates that the fluorescent agent was not dissolved in the silicone compound.
Further, in Tables 3 and 4, those in which the fluorescent agent dissolves in 0.1% by mass or more with respect to the silicone compound are “Δ”, those in which 0.25% by mass or more are dissolved are “◯”, and those in which 0.5% by mass or more are dissolved are “○”. Solubility was evaluated with those that dissolve as "⊚".

(result)
It was found that all of the fluorescent agents tested were reasonably soluble in the silicone compounds. Further, it was found that among them, the coumarin-based fluorescent agents A to C and the naphthalene-based fluorescent agents B and C were particularly highly soluble in the silicone compound.

Summarizing the results so far, from the results in Tables 1, 3 and 4, the coumarin-based fluorescent agents B to E and the naphthalene-based fluorescent agents A to C have high heat resistance and are appropriately dissolved in the silicone compound. I found out that Further, among them, it was found that the coumarin-based fluorescent agents B and C and the naphthalene-based fluorescent agents B and C were particularly excellent in heat resistance and solubility in silicone compounds.
Therefore, according to the mold release agents of Examples 1 to 7, it is considered that the adhered state of the mold release agent in the high temperature mold can be easily confirmed. Further, among them, the release agents of Examples 1, 2, 6 and 7 are considered to be particularly excellent.

<Concentration test>
Next, the change in light emission due to the change in the content of the fluorescent agent with respect to the silicone compound was examined. The test method is as follows. After spraying the mold release agent on the high temperature steel sheet, the mold was irradiated with ultraviolet rays, and the light emission of the mold release agent was visually confirmed. Those that could barely confirm the light emission were evaluated as "Δ", those that could clearly confirm the light emission were evaluated as "○", and those that could confirm the light emission more clearly were evaluated as "◎". The results are shown in Tables 5 and 4, and the test conditions are shown in Table 6.
The release agent used in the test was prepared as follows. First, the naphthalene-based fluorescent agent B was dissolved in an organomodified silicone compound (C12 alkyl group (dodecyl group): C9 aralkyl group (2-methylphenethyl group) = 4: 1, viscosity 1500 mPa · s at 25 ° C.). The content of the fluorescent agent in the obtained solution is shown in Table 5. Then, the above solution was emulsified with a surfactant (polyoxyethylene polyoxypropylene isodecyl ether (EO isodecyl ether)) and water. At this time, the contents of the fluorescent agent and the silicone compound were set to 25% by mass based on the entire release agent. The content of the surfactant was 0.1% by mass based on the entire release agent.

(result)
The release agents of Examples 8 and 9 were barely luminescent, which is considered to be due to the small amount of adhesion as in the results of Examples 3 and 4 at 300 ° C. On the other hand, with the release agent of Example 10 in which the content of the fluorescent agent was 0.25% by mass, luminescence was clearly confirmed. In Examples 11 and 12 in which the content of the fluorescent agent was even larger, the light emission could be confirmed more clearly.

<Oil test>
The studies so far have been made when a fluorescent agent is used as an aqueous mold release agent. Therefore, here, a case where a fluorescent agent is contained in an oil-based release agent is examined.
The test method is as follows. After spraying the mold release agent on the high temperature steel sheet, the mold was irradiated with ultraviolet rays, and the light emission of the mold release agent was visually confirmed. Those for which light emission could not be visually confirmed were evaluated as "x", and those for which light emission could be clearly confirmed were evaluated as "○". The results are shown in Tables 7 and 5, and the test conditions are shown in Table 8.
The release agent used in the test was prepared as follows. First, the fluorescent agent is dissolved in an organomodified silicone compound (C12 alkyl group (dodecyl group): C9 aralkyl group (2-methylphenethyl group) = 4: 1, viscosity at 25 ° C. of 1500 mPa · s), and the content of the fluorescent agent. A solution was obtained in which was 0.2% by mass. Then, the above solution was diluted with a hydrocarbon solvent (paraffins). At this time, the content of the fluorescent agent and the silicone compound was set to 15% by mass based on the entire release agent.

(result)
Similar to the results in Table 1, no luminescence could be confirmed in Comparative Example 5 using a fluorescent agent having no 6/6 membered ring condensed ring structure. On the other hand, in Example 13 using a fluorescent agent having a condensed ring structure of a 6/6 member ring and a large molecular weight, luminescence could be clearly confirmed.
Therefore, it was found that the fluorescent agent of the present disclosure can also be used as an oil-based mold release agent.

Claims (7)

Contains a silicone compound and a fluorescent agent that emits light when irradiated with UV light at 365 nm.
The fluorescent agent has a coumarin skeleton of the structure shown below SL (3), the molecular weight of the fluorescent agent is 300 or more 600 or less,
Release agent composition for die casting.

R ⁴ represents hydrogen, straight-chain or branched alkyl group having 1 to 4 carbon atoms, benzimidazole group, benzoxazole group, or a benzothiazole group. Y represents an ^NR _{5 2} or OR ^{5, R 5} represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms. Z represents a methylene group, an ethylene group, a methylmethylene group, a dimethylmethylene group, a carbonyl group, or a sulfonyl group. The mold release agent composition for die casting according to claim 1, wherein the content of the fluorescent agent is 0.1% by mass or more and 3.0% by mass or less based on the total of the silicone compound and the fluorescent agent. The mold release agent composition for die casting according to claim 1 or 2, wherein the content of the silicone compound is 5% by mass or more and 50% by mass or less based on the entire composition. The mold release agent composition for die casting according to any one of claims 1 to 3, further comprising a hydrocarbon solvent. The mold release agent composition for die casting according to any one of claims 1 to 3, further comprising a surfactant and water. The mold release agent composition for die casting according to claim 5, which is emulsified. A step of dissolving a fluorescent agent that emits light by irradiation with ultraviolet rays of 365 nm in a silicone compound is provided.
The fluorescent agent has a coumarin skeleton of the structure shown below SL (3), the molecular weight of the fluorescent agent is 300 or more 600 or less,
A method for producing a mold release agent composition for die casting.

R ⁴ represents hydrogen, straight-chain or branched alkyl group having 1 to 4 carbon atoms, benzimidazole group, benzoxazole group, or a benzothiazole group. Y represents an ^NR _{5 2} or OR ^{5, R 5} represents hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms. Z represents a methylene group, an ethylene group, a methylmethylene group, a dimethylmethylene group, a carbonyl group, or a sulfonyl group.

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