WO2025100445A1 - Coating agent composition for casting, method for producing cast article, and method for suppressing sand quenching - Google Patents

Abstract

This coating agent composition for casting is used for application to a surface of a mold manufactured using a refractory aggregate and an inorganic binder, wherein: the coating agent composition for casting contains a water-soluble base (A) having a boiling point of 200°C or higher, and water; and the inorganic particle content is 2 mass% or less with respect to the total amount of the coating agent composition for casting.

Description

Casting wash composition, casting manufacturing method, and method for inhibiting sand adhesion

The present invention relates to a casting wash composition, a method for producing castings, and a method for inhibiting sand adhesion.

In recent years, molding processes using inorganic binders instead of organic binders as mold binders have been attracting attention. When inorganic binders are used, the odors generated during molding and the tar, gas, and odors generated during pouring, which are generated by organic binders, are suppressed, but it is known that "sand adhesion", in which sand adheres to the surface of the casting, can occur depending on the shape and material of the casting.
Possible causes of "sand burn-in" include the infiltration of molten metal into the tiny gaps between the sand particles in the mold and the reaction between the inorganic binder and the molten metal.

Therefore, before pouring molten metal into the mold (also called a core), a mold wash is applied to the surface of the mold to protect the mold.
As such a mold wash, for example, a paste or suspension base material containing inorganic aggregate such as silica, talc, etc. and dispersing the same is known. However, conventional mold washes have problems such as the dispersed inorganic aggregate settling after a certain period of storage, making it necessary to redisperse the mold wash when it is used, and causing unevenness when spraying the mold wash.

For example, Patent Document 1 (JP 2018-118302 A) describes an aqueous mold wash for inorganic cores that contains an organic thickener in addition to refractory aggregate and water as a solvent, and has a viscosity of 500 to 2000 mPa·s, from the viewpoint of suppressing clogging of the spray nozzle and stably spraying. It also discloses that the content of the organic thickener is 0.1 to 1 part by mass per 100 parts by mass of refractory aggregate, and that the content of the water solvent is 100 to 500 parts by mass per 100 parts by mass of refractory aggregate.

JP 2018-118302 A

However, the inventors have found that the mold wash described in Patent Document 1 still does not have sufficient storage stability.

The inventors therefore conducted extensive research to improve storage stability while suppressing sand burn-in adhesion, and discovered that by using a water-soluble base (A) with a boiling point of 200°C or higher, sand burn-in adhesion can be suppressed without the need for inorganic aggregate. They also discovered that not requiring inorganic aggregate can dramatically improve storage stability, leading to the completion of the present invention.

According to the present invention,
A casting wash composition for use in applying to a surface of a mold made using a refractory aggregate and an inorganic binder, comprising:
The present invention provides a casting mold wash composition comprising a water-soluble base (A) having a boiling point of 200° C. or higher and water, and a content of inorganic particles in the casting mold wash composition is 2 mass % or less based on the total amount of the casting mold wash composition.

Further, according to the present invention,
A method for manufacturing a casting using a mold manufactured using a refractory aggregate and an inorganic binder, comprising the steps of:
applying a casting wash composition to a surface of the mold;
pouring a metal material into the mold having the casting wash composition applied to its surface to obtain a casting;
having
The casting mold wash composition contains a water-soluble base (A) having a boiling point of 200°C or more and water, and the content of inorganic particles is 2 mass% or less based on the total amount of the casting mold wash composition.

According to the present invention, there is also provided a method for inhibiting sand adhesion to a casting obtained by using a mold produced by using a refractory aggregate and an inorganic binder, comprising the steps of:
applying a casting wash composition to a surface of the mold;
pouring a metal material into the mold having the casting wash composition applied to its surface to obtain a casting;
having
The casting mold wash composition contains a water-soluble base (A) having a boiling point of 200° C. or more and water, and the content of inorganic particles is 2 mass% or less based on the total amount of the casting mold wash composition.

The present invention provides a casting wash composition that suppresses sand adhesion to castings while providing good storage stability.

FIG. 2 is a cross-sectional view showing a schematic configuration of a casting test mold of the embodiment.

The following describes the embodiments of the present invention. In this specification, unless otherwise specified, "a-b" indicating a numerical range represents a range from a to b, and includes both ends of the range. In addition, the configurations and elements described in each embodiment can be combined as appropriate as long as the effect of the invention is not impaired.

<Casting Mold Wash Composition>
The casting mold wash composition of this embodiment is used for application to the surface of a mold manufactured using a refractory aggregate and an inorganic binder, and contains water and a water-soluble base (A) having a boiling point of 200°C or higher, and the content of inorganic particles is 2 mass% or less based on the total amount of the casting mold wash composition.

This makes it possible to suppress sand adhesion to a casting obtained from a mold to which the casting wash composition is applied, while improving the storage stability of the casting wash composition. Although the details of this mechanism are not clear, it is speculated as follows.
The casting wash composition of this embodiment is applied to the surface of the mold, and can suppress the intrusion of molten metal into the small gaps between the sand particles of the mold. In addition, the water-soluble base (A) in the casting wash composition is partially gasified by the heat of the molten metal to form a gas film, so that the intrusion of the molten metal can be suppressed to a higher degree. In addition, the casting wash composition of this embodiment has an inorganic particle content of 2 mass% or less with respect to the total amount of the casting wash composition, so that the settling of inorganic particles is reduced and the storage stability is improved, and when the casting wash composition is sprayed, clogging of the spray nozzle by inorganic particles can be reduced. As a result, the casting wash composition can be appropriately applied to the mold, and the sand burn-in adhesion to the casting can be more stably suppressed.

[Physical Properties]
The viscosity of the casting mold wash composition is preferably 0.5 mPa·s or more, more preferably 0.7 mPa·s or more, and even more preferably 1.0 mPa·s or more. By making the viscosity of the casting mold wash composition equal to or more than the above lower limit, the coating property of the casting mold wash composition is improved while maintaining good storage stability, and sand-burning adhesion to the casting can be easily suppressed.
On the other hand, the viscosity of the casting mold wash composition is preferably 1200 mPa·s or less, more preferably 500 mPa·s or less, and even more preferably 125 mPa·s or less. By making the viscosity of the casting mold wash composition equal to or less than the upper limit, it becomes easier to improve the storage stability.

The viscosity of the casting wash composition is measured at 25°C using an E-type viscometer (Toki Sangyo Co., Ltd. VISCOMETER RE-85L).

Methods for adjusting the viscosity of the casting mold wash composition include selecting a water-soluble base (A) with a boiling point of 200°C or higher, adjusting the content, and the presence or absence of inorganic particles, selecting inorganic particles, and adjusting the content.

The components contained in the casting wash composition are explained below.

[Water-soluble base (A)]
The water-soluble base (A) is a water-soluble substance having a boiling point of 200° C. or higher, and is preferably an organic substance.
The water-soluble base (A) may be, for example, one or more selected from the group consisting of polyhydric alcohols, polystyrene sulfonates, naphthalenesulfonic acid-formalin condensates, and polyacrylic acids.
Examples of polyhydric alcohols include sugar alcohols such as glycerin (290° C.), erythritol (330° C.), and pentaerythritol (276° C.); hydroxyalkyl celluloses such as hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose; carboxyalkyl celluloses such as carboxymethyl cellulose, carboxyethyl cellulose, and carboxypropyl cellulose; monosaccharides such as glucose (233° C.), fructose (440° C.), and galactose (233° C.); polyethylene glycol, etc. The boiling points are shown in parentheses.
Examples of the polystyrene sulfonate include sodium polystyrene sulfonate and potassium polystyrene sulfonate.
When the water-soluble base (A) is a polymer, a polymer having a boiling point of 200° C. or higher can be selected and used.

The content of the water-soluble base (A) is preferably 0.7 mass% or more, more preferably 1.0 mass% or more, and even more preferably 2.0 mass% or more, based on the total amount of the casting mold wash composition, from the viewpoints of improving the handleability of the casting mold wash composition, suppressing sand burn-in adhesion to castings, and improving storage stability.
On the other hand, the content of the water-soluble base (A) is preferably 15 mass % or less, more preferably 12 mass % or less, and even more preferably 10 mass % or less, based on the total amount of the casting mold wash composition, in order to improve the coatability of the casting mold wash composition, suppress sand burn-in adhesion, and improve storage stability.
"Water-soluble" means having a solubility of 2 g/100 mL or more in water (20° C.).
"Boiling point" refers to the standard boiling point (boiling point under 1 atmospheric pressure), and the boiling point was measured according to JIS K2254, with the initial boiling point being the boiling point. For water-soluble bases with boiling points exceeding 200°C, the measurement is terminated when the boiling point exceeds 200°C. When two or more water-soluble bases are used, the boiling point value is a weighted average value weighted by the content (mass%) of each water-soluble base material. When chemical decomposition occurs before the boiling point is reached, the decomposition point is treated as equivalent to the boiling point.

[Inorganic particles]
In this embodiment, the inorganic particles are an optional component.
The content of inorganic particles is 2% by mass or less, preferably 1% by mass or less, more preferably 0.5% by mass or less, based on the total amount of the casting mold wash composition, and the casting mold wash composition may be free of inorganic particles, thereby making it possible to prevent the inorganic particles from settling in the casting mold wash composition and to prevent clogging when the casting mold wash composition is sprayed.

In this embodiment, the inorganic particles are particles made of an inorganic compound that is insoluble in water, and there are no particular limitations on the shape, size, etc.

The inorganic particles are refractory aggregates for casting mold wash compositions, and examples of such particles include one or more selected from crystalline silica such as quartz, amorphous silica such as fused silica and colloidal silica, zircon, zirconia, magnesia, olivine, spinel, alumina, chamotte, mullite, andalusite, sillimanite, kyanite, talc, chromite, mica, pottery stone, obsidian, perlite, glass, frit, diatomaceous earth, rosewood, vermiculite, expanded shale, aluminium shale, graphite, carbon, Gilsonite, zinc oxide, calcium oxide, titanium oxide, iron oxide, manganese oxide, zinc carbonate, magnesium carbonate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, etc.

The average particle size of the inorganic particles may be, for example, 0.01 μm or more, 0.1 μm or more, or 0.3 μm or more. On the other hand, the average particle size of the inorganic particles may be, for example, 500 μm or less, 300 μm or less, or even 200 μm or less.

[solvent]
In the casting wash composition of the present embodiment, water is used as a solvent. A solvent other than water may be used in combination, but from the viewpoints of safety and economy, the content of water in the solvent is preferably 98% by mass or more, more preferably 99% by mass or more, and even more preferably substantially 100% by mass.
Examples of the solvent other than water include one or more alcohols such as methanol, ethanol, propanol, isopropanol, butanol, and hexanol. Among these, ethanol is preferred from the viewpoints of cost and coating workability.

[others]
The casting mold wash composition of the present embodiment may further contain, in addition to the water-soluble base (A) and any inorganic particles, a binder, a dispersant, a surfactant, a colorant, a preservative, and the like, as necessary.

[Application]
The casting wash composition is applied to the surface of a mold made using a refractory aggregate and an inorganic binder. The mold is not particularly limited as long as it uses a refractory aggregate and an inorganic binder, and any known mold can be used.
Specifically, for example, the mold may be made of inorganic coated sand containing refractory aggregate and an inorganic binder layer formed on the surface of the refractory aggregate. The inorganic coated sand will be described below.

(Inorganic coated sand)
The inorganic coated sand contains a refractory aggregate and an inorganic binder layer on the surface of the refractory aggregate.
The casting wash composition of the present embodiment can be applied to either dry inorganic coated sand or wet inorganic coated sand.
The term "dry state" refers to a state in which the material has flowability at room temperature. More specifically, the term refers to a state in which the dynamic angle of repose can be measured regardless of the moisture content. The term "wet state" refers to a state in which the inclined surface of the material is not flat when the dynamic angle of repose is measured, and the dynamic angle of repose cannot be measured.

The refractory aggregate for the inorganic coated sand may be natural sand or artificial sand.
Examples of natural sand include silica sand, which is mainly composed of quartz, chromite sand, zircon sand, olivine sand, and alumina sand.
Examples of artificial sand include synthetic mullite sand, _SiO2 -based casting sand mainly composed of SiO2 _{, Al2O3} -based casting sand mainly composed of _Al2O3 , _SiO2 / _{Al2O3 -} based casting sand, _SiO2 /MgO-based casting sand, _SiO2 / _Al2O3 / _{ZrO2 -} based casting sand, _SiO2 / _Al2O3 / _{Fe2O3 - based} casting sand, and casting sand derived from slag. Here, the main component refers to the component that is the most abundant among _the components contained _in the sand. Artificial sand refers to casting sand that is not naturally produced, but is artificially prepared from metal oxide components and melted or sintered. In addition, recycled sand obtained by recovering used refractory aggregate and regenerated sand obtained by regenerating recycled sand can also be used.
These may be used alone or in combination of two or more.

The refractory aggregate is preferably in the form of particles from the viewpoint of improving the fluidity of the inorganic coated sand and further improving the filling property into a molding die.
The average particle size of the refractory aggregate for the inorganic coated sand is preferably 0.05 mm or more, more preferably 0.10 mm or more, from the viewpoints of improving mold quality and mold strength, and of ease of mold making. If the average particle size of the refractory aggregate is equal to or more than the above lower limit, the amount of inorganic binder layer used during mold production can be reduced, which is also preferable in that it makes it easier to regenerate the inorganic coated sand.
The average particle size of the refractory aggregate for the inorganic coated sand is preferably 2.0 mm or less, more preferably 1.0 mm or less, and even more preferably 0.5 mm or less, from the viewpoints of improving mold quality and mold strength, and of ease of mold making. In addition, if the average particle size of the refractory aggregate is equal to or less than the above upper limit, it is also preferable in that the porosity is reduced during mold production, and the mold strength can be increased.

The inorganic binder layer is formed on the surface of the fire-resistant aggregate, and serves as a coating layer that covers the surface of the fire-resistant aggregate. However, the coating does not have to be continuous, and may have some discontinuous areas.

The inorganic binder layer may further contain inorganic fine particles in addition to the inorganic binder. In the case of a dry state, for example, the inorganic binder layer may be a layer in which an inorganic binder and inorganic fine particles are mixed and coated; a layer in which an inorganic binder-coated layer is further coated with inorganic fine particles; or a layer in which an inorganic binder and inorganic fine particles are mixed and coated with inorganic fine particles and further coated with inorganic fine particles.
In the case of a wet state, the inorganic binder layer can be in a state where the liquid inorganic binder and the inorganic fine particles are intimately mixed together and adhere to the refractory aggregate.

The inorganic binder has a function of firmly binding the mold sands together so that a desired mold can be obtained when the mold is made using the inorganic coated sand. The inorganic binder is also one component constituting the inorganic binder layer.
The inorganic binder includes, for example, a water-soluble silicic acid compound, and preferably includes at least one selected from sodium silicate and sodium metasilicate. The inorganic binder may further include a binder mainly composed of a water-soluble silicic acid compound other than the above. Specific examples of silicic acid compounds other than sodium silicate and sodium metasilicate include potassium silicate, potassium metasilicate, lithium silicate, and ammonium silicate.

The inorganic fine particles, for example, strongly bond the particles of the inorganic coated sand to each other, and as a result, the strength of the obtained mold can be further improved. The inorganic fine particles are not limited, but for example, SiO _{2 -} containing fine particles, silicon particles, zinc oxide, etc. are listed. From the viewpoint of improving the strength of the mold, SiO _2- containing fine particles and zinc oxide are preferable, and from the viewpoint of large specific surface area and high reactivity with sodium silicate and sodium metasilicate, SiO 2-containing fine particles are more preferable. These inorganic fine particles may be used alone or in combination of two or more kinds.

The inorganic binder layer may contain known additives such as coupling agents, lubricants, and release agents as components other than the inorganic binder.

[Method for preparing casting wash composition]
The casting wash composition of the present embodiment can be obtained by mixing and stirring the water-soluble base (A), water, and any optional components by a known method.

<Casting manufacturing method>
The method for producing castings of the present embodiment is a method for producing castings using a mold produced using a refractory aggregate and an inorganic binder, and includes the following steps using a casting wash composition that contains a water-soluble base (A) having a boiling point of 200° C. or more and water, and has an inorganic particle content of 2 mass% or less based on the total amount of the casting wash composition.
(Step 1) A step of applying a casting wash composition to the surface of a mold.
(Step 2) A step of pouring a metal material into the mold having the casting wash composition applied to its surface to obtain a casting.

The details of each process are explained below.

(Step 1)
First, a casting wash composition is applied to the surface of a mold made from a refractory aggregate and an inorganic binder.
The casting wash composition can be applied by a conventional method such as pouring, immersion, brushing, or spraying. Among them, the method of applying the casting wash composition to the surface of the mold, such as brushing or spraying, or the method of immersing the mold in the casting wash composition (dip immersion) is preferred. The application may be performed by applying the casting wash composition using a brush or the like, or by spraying the casting wash composition using a tool.

The amount of the casting wash composition applied can be appropriately adjusted depending on the size, shape, etc. of the mold.
After the casting wash composition has been applied to the mold, it may be allowed to dry naturally or may be dried by heating.

In a process for molding a mold using a heated mold, the mold has residual heat immediately after production, and when the mold wash composition for casting is applied to the mold, the solvent component in the mold wash composition for casting can evaporate immediately, so that the drying step can be omitted. In order to omit the drying step, the surface temperature of the mold is preferably 100° C. or higher, more preferably 120° C. or higher, and even more preferably 150° C. or higher.
From the viewpoint of uniformly fixing the casting wash composition to the mold surface, the surface temperature of the mold is preferably 300° C. or lower, more preferably 250° C. or lower, even more preferably 200° C. or lower, and still more preferably 180° C. or lower.

The above-mentioned casting mold wash composition can be used as the casting mold wash composition.

(Step 2)
A desired casting can be obtained by pouring a metal material into the mold with the casting wash composition applied to the surface thereof and cooling and solidifying it. The casting wash composition can be suitably used in any of the casting manufacturing methods including gravity die casting, low pressure casting, die casting, lost foam casting (full mold method), and sand casting.

The metal material is not particularly limited and any known material can be used, but non-ferrous alloys such as aluminum alloys, copper alloys, and magnesium alloys are preferable in order to effectively prevent sand adhesion to the casting.

<Method for suppressing sand burning>
The method for inhibiting sand burn-in of this embodiment is a method for inhibiting sand burn-in to a casting in a casting production process using a mold manufactured using a refractory aggregate and an inorganic binder, by using a casting mold wash composition that contains a water-soluble base (A) having a boiling point of 200°C or more and water, and has an inorganic particle content of 2 mass% or less based on the total amount of the casting mold wash composition, and by including the following steps:
(Step 3) applying a casting wash composition to the surface of the mold;
(Step 4) A step of pouring a metal material into the mold with the casting wash composition applied to its surface to obtain a casting. Note that "sand burn-in" refers to a phenomenon in which components including sand derived from the refractory aggregate used in mold production are burned onto the surface of the casting during the manufacturing process.

Step 3 can be the same as that described in step 1 above. Also, step 4 can be the same as that described in step 2 above.

The above describes the embodiments of the present invention, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted. Furthermore, modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention.

In relation to the above-mentioned embodiments, the present invention further discloses the following mold wash composition for casting, method for producing a casting, and method for inhibiting sand burn-in adhesion.
<1> A casting wash composition used to apply to a surface of a casting mold produced using a refractory aggregate and an inorganic binder,
A casting mold wash composition comprising: a water-soluble base (A) having a boiling point of 200° C. or higher; and water; a content of inorganic particles is 2 mass % or less, preferably 1 mass % or less, and more preferably 0.5 mass % or less, based on the total amount of the casting mold wash composition; and the casting mold wash composition may be free of inorganic particles.
<2> The casting mold wash composition according to <1>, wherein the viscosity of the casting mold wash composition is preferably 0.5 mPa·s or more, more preferably 0.7 mPa·s or more, even more preferably 1.0 mPa·s or more, and is preferably 1200 mPa·s or less, more preferably 500 mPa·s or less, and even more preferably 125 mPa·s or less.
<3> The casting wash composition according to <1> or <2>, wherein the water-soluble base (A) contains one or more selected from the group consisting of polyhydric alcohols, polystyrene sulfonates, naphthalenesulfonic acid-formalin condensates, and polyacrylic acids.
<4> A method for manufacturing a casting using a mold manufactured using a refractory aggregate and an inorganic binder, comprising:
applying a casting wash composition to a surface of the mold;
pouring a metal material into the mold having the casting wash composition applied to its surface to obtain a casting;
having
The casting mold wash composition contains a water-soluble base (A) having a boiling point of 200°C or more and water, and the content of inorganic particles is 2 mass% or less, preferably 1 mass% or less, and more preferably 0.5 mass% or less, based on the total amount of the casting mold wash composition, and the casting mold wash composition may not contain inorganic particles.
<5> In the step of applying the casting wash composition,
The method for producing a casting according to <4>, further comprising applying the mold wash composition for casting or immersing the mold in the mold wash composition for casting.
<6> In the step of applying the casting wash composition,
The method for producing a casting according to <4> or <5>, wherein the surface temperature of the mold is 100°C or higher, preferably 120°C or higher, more preferably 150°C or higher, and is preferably 300°C or lower, more preferably 250°C or lower, even more preferably 200°C or lower, and still more preferably 180°C or lower.
<7> In the step of applying the casting wash composition,
The method for producing a casting according to any one of <4> to <6>, wherein the metal material is a non-ferrous alloy.
<8> A method for suppressing sand adhesion to a casting obtained by using a mold manufactured by using a refractory aggregate and an inorganic binder, comprising:
applying a casting wash composition to a surface of the mold;
pouring a metal material into the mold having the casting wash composition applied to its surface to obtain a casting;
having
The casting mold wash composition contains a water-soluble base (A) having a boiling point of 200°C or higher and water, and the content of inorganic particles is 2 mass% or less, preferably 1 mass% or less, and more preferably 0.5 mass% or less, based on the total amount of the casting mold wash composition, and may be free of inorganic particles.
<9> In the step of applying the casting wash composition,
The method for suppressing sand burn-in adhesion according to <8>, comprising coating the casting mold wash composition or immersing the mold in the casting mold wash composition.
<10> In the step of applying the casting wash composition,
The method for suppressing sand burn-in adhesion according to <8> or <9>, wherein the surface temperature of the mold is 100° C. or higher, preferably 120° C. or higher, more preferably 150° C. or higher, and is preferably 300° C. or lower, more preferably 250° C. or lower, even more preferably 200° C. or lower, and still more preferably 180° C. or lower.

The present invention will be explained below with reference to examples and comparative examples, but the present invention is not limited to these.

(1) Materials The materials used in the following Examples and Comparative Examples will be described.
[Raw materials for casting wash composition]
Water-soluble base 1: Hydroxypropylcellulose NISSO HPC-L (manufactured by Nippon Soda Co., Ltd., average molecular weight 140,000, active content 100%)
Water-soluble base 2: Hydroxyethylcellulose Natrosol 250L (manufactured by Ashland, average molecular weight 90,000, effective 100%)
Water-soluble base 3: Sodium carboxymethylcellulose Cellogen WS-C (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., average molecular weight 70,000, active content 100%)
Water-soluble base 4: Sodium polystyrene sulfonate PS-35 (manufactured by Tosoh Finechem Co., Ltd., average molecular weight 300,000 to 400,000, active content 21%)
Water-soluble base 5: Polyethylene glycol 20,000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average molecular weight 20,000, active content 100%)
Water-soluble base 6: Polyacrylic acid 25,000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average molecular weight 25,000, active content 100%)
Water-soluble base 7: Mighty 150 (Kao Corporation, aqueous solution of naphthalenesulfonic acid formalin high condensate salt, active ingredient 40%)
Water-soluble base 8: D(+)-glucose (manufactured by Fujifilm Wako Pure Chemical Industries, active ingredient 100%)
Water-soluble base 9: Pentaerythritol (manufactured by Fujifilm Wako Pure Chemical Industries, active ingredient 100%)
Water-soluble base 10: Glycerin (manufactured by Fujifilm Wako Pure Chemical Industries, active ingredient 100%)
Water-soluble base 11: 2-ethoxyethanol (manufactured by Fujifilm Wako Pure Chemical Industries, active ingredient 100%)
Inorganic particle 1: Snowtex-C (Nissan Chemical Co., Ltd., aqueous dispersion of silica particles, particle size 12 nm, effective content 20%)

The materials used in the casting wash composition of Comparative Example 5 will be described below.
Refractory aggregate 3: Silica (average particle size: 20 μm, effective content 100%)
Thickening polysaccharide: Xanthan gum KELZAN (manufactured by Sansho Co., Ltd., active content 100%)
Nonionic surfactant: Smack MP-40 (Kao Corporation, active ingredient 100%)
Silicone-based defoamer: Defoamer No. 8 (Kao Corporation, active ingredient 100%)
Vinyl acetate emulsion: Vinyblan (manufactured by Nissin Chemical Industry Co., Ltd., active content 32%)

[Raw material for inorganic coated sand]
Refractory aggregate 1: Mikawa silica sand R6 (manufactured by Mikawa Silica Co., Ltd., average particle size: 200 μm, sphericity: 0.85)
Refractory aggregate 2: Espearl #60L (manufactured by Yamakawa Sangyo Co., Ltd., average particle size: 241 μm, amorphous degree 45%, sphericity 0.97)
Inorganic binder 1: Sodium metasilicate (9-hydrate) (manufactured by Nippon Chemical Industry Co., Ltd., Na ₂ SiO _{3.9H 2} O, SiO ₂ /Na ₂ O molar ratio = 0.9 to 1.1, melting point 47°C)
Inorganic binder 2: No. 2 sodium silicate (manufactured by Fuji Chemical Industry Co., Ltd., No. 2 water glass, SiO ₂ /Na ₂ O molar ratio = 2.4)
Inorganic fine particles 1: Denka fused silica SFP-20M (manufactured by Denka, average particle size: 0.4 μm, degree of amorphousness 99.5% or more, _SiO2 mass %: 99% or more)

[Raw materials used in casting tests]
・Mikawa silica sand R6 (manufactured by Mikawa Silica Co., Ltd., average particle size: 200 μm, sphericity: 0.85)
・Kao Step SH-8010 (Kao Quaker)
・Kao Step DH-25 (Kao Quaker)

(2) Preparation of Casting Mold Wash Composition <Example 1>
Water (98 parts by mass) was weighed into a container and stirred using a magnetic stirrer. Water-soluble base 1 (hydroxypropyl cellulose) was gradually added to the container while stirring the water, and stirring was continued until the water-soluble base 1 (2 parts by mass) was completely dissolved, to prepare a uniform, transparent liquid casting wash composition.

<Examples 2 to 21, Comparative Examples 2 and 3>
Casting wash compositions were prepared in the same manner as in Example 1, except that the amounts of water, each of the water-soluble bases 1 to 11, and any of the inorganic particles shown in Tables 1 and 2 were used.

<Comparative Example 5>
Using the raw materials shown in Table 1, water (140 parts by mass) was weighed out into a container, and thickening polysaccharide (0.2 parts by mass) was added little by little while stirring the water with a homodisper. Then, while continuing to stir, refractory aggregate 3 (100 parts by mass), nonionic surfactant (0.5 parts by mass), silicon-based defoamer (0.2 parts by mass), and vinyl acetate emulsion (2 parts by mass) were added in this order to prepare a casting wash composition in which refractory aggregate 3 was uniformly dispersed.

(3) Viscosity Measurement The viscosity of each of the casting wash compositions of Examples 1 to 21 and Comparative Examples 2 and 3 was measured at a liquid temperature of 25° C. using an E-type viscometer (VISCOMETER RE-85L manufactured by Toki Sangyo Co., Ltd.).
In addition, for the casting wash composition of Comparative Example 5, the viscosity was measured for 1 minute at a rotation speed of 6 rpm with a No. 2 rotor using a Brookfield viscometer (VISCOMETER TVB-10 manufactured by Toki Sangyo Co., Ltd.) at a liquid temperature of 25° C.
The results are shown in Tables 1 and 2.

(4) Measurement of boiling point of water-soluble base material The measurement was carried out according to JIS K2254, and the initial boiling point was regarded as the boiling point. For water-soluble base materials with boiling points exceeding 200°C, the measurement was stopped at the stage where the temperature exceeded 200°C, and the temperature was expressed as ">200"°C. The results are shown in Tables 1 and 2.

(5) Preparation of inorganic coated sand [Production Example 1]
Example 1
Refractory aggregate 1 (Mikawa silica sand R6) (100 parts by mass) was charged into the mixer. Next, inorganic binder 1 (5.0 parts by mass) that had been heated to 80° C. and melted was charged into the mixer and kneaded for 4 minutes to obtain dry inorganic coated sand having room temperature fluidity.

[Production Example 2]
<Examples 2 to 5, 8 to 12, 14 to 19, Comparative Example 1>
Refractory aggregate 1 (Mikawa silica sand R6) (100 parts by mass) was added to the mixer. Next, inorganic binder 1 (3.0 parts by mass) that had been heated to 80° C. and melted was added to the mixer and mixed for 4 minutes to obtain dry sand with room temperature fluidity. After that, inorganic fine particles 1 (0.9 parts by mass) were added and mixed for 2 minutes to obtain inorganic coated sand.

[Production Example 3]
<Examples 6, 7, 13, 20, and Comparative Examples 2 to 5>
Refractory aggregate 2 (Espearl #60L) (100 parts by mass) was added to the mixer. Next, inorganic binder 1 (2.0 parts by mass) that had been heated to 80°C and melted was added to the mixer and kneaded for 4 minutes to obtain dry sand with room temperature fluidity. Thereafter, inorganic fine particles 1 (0.6 parts by mass) were further added and kneaded for 2 minutes to obtain inorganic coated sand.

[Production Example 4]
<Example 21, Comparative Example 6>
Refractory aggregate 1 (Mikawa silica sand R6) (100 parts by mass) was charged into the mixer. Next, inorganic binder 2 (3.0 parts by mass) was charged into the mixer and kneaded for 2 minutes to obtain wet inorganic coated sand.

(6) Preparation of mold test pieces and application of casting wash composition A mold for 22.3 x 22.3 x 180 mm test pieces (5 pieces) was heated to 180°C. For the inorganic coated sand of each example, a CSR-43 blow molding machine was used, and the inorganic coated sand was filled at a blow pressure of 0.3 MPa in <Examples 1 to 20, Comparative Examples 1 to 5> and at a blow pressure of 4.5 MPa in <Example 21, Comparative Example 6>. The inorganic coated sand was then allowed to stand in this molding mold for 150 seconds to harden, and the mold test piece was molded, and the mold test piece was removed from the mold.
Immediately after removal from the mold, each side surface (four sides in total) of the mold test piece (mold surface temperature: 150-180°C) was coated with a spray gun (WIDER1, manufactured by ANEST IWATA CORPORATION) with a casting wash composition corresponding to the inorganic coated sand of each Example and Comparative Example shown in Tables 1 and 2. The casting wash compositions used were those that had been prepared 24 hours earlier, and the spray gun was appropriately adjusted so that each casting wash composition was atomized.
Thereafter, the mold test pieces were left at room temperature for about 10 minutes, after which the solvent component of the casting wash composition applied to the surface of the mold test pieces evaporated due to the heat of the mold test pieces, and the mold test pieces were dried.

(7) Casting Evaluation Casting tests were carried out using the mold test pieces of <Examples 1 to 21> and <Comparative Examples 1 to 6> prepared in the above (6). Figure 1 is a cross-sectional view showing the schematic configuration of the mold for the casting test.
First, Mikawa silica sand R6 (100 parts by mass), Kaostep SH-8010 (1.2 parts by mass), and Kaostep DH-25 (0.24 parts by mass) were mixed in a mixer to prepare the master mold shown in Fig. 1. The master mold was composed of an upper mold 103a and a lower mold 103b, and had a width (left-right direction in Fig. 1) of 340 mm, a depth (direction perpendicular to the paper surface in Fig. 1) of 250 mm, and a height from the bottom surface of the lower mold 103b to the top surface of the upper mold 103a of 200 mm.
Next, the mold test pieces of Examples 1 to 21 and Comparative Examples 1 to 6 were set in the main mold as cores 101, and 8.5 kg of aluminum alloy (equivalent to AC4C) at a pouring temperature of 720° C. was poured from the gate 105. After cooling, the mold test pieces (cores 101) were removed from the castings, and the castings were then cut and the parts where the mold test pieces (cores 101) had been in contact with the castings were visually observed and evaluated according to the following criteria. The results are shown in Tables 1 and 2.
Criteria: If the area of sand burned into the part of the mold test piece (core 101) that had been in contact with the casting was less than 1% of the total area of the parts where the mold (core 101) and the casting had been in contact with each other, it was evaluated as "4", if it was 1% or more but less than 5%, it was evaluated as "3", if it was 5% or more but less than 10%, it was evaluated as "2", and if it was 10% or more, it was evaluated as "1".

(8) Evaluation of Stability of Mold Wash Composition The casting mold wash composition prepared in (2) above was transferred to a screw tube (manufactured by AS ONE Corporation, 110 cc, product number 9-852-10 No. 8) and left to stand for 24 hours. The state of the casting mold wash composition was visually evaluated according to the following criteria. The results are shown in Tables 1 and 2.
Criterion 0: A uniform, transparent or dispersed liquid was maintained (no sediment at the bottom of the screw tube) and was usable.
×: The fire-resistant aggregate settled and the water separated, so the material was unusable.

101: Core 103a: Upper mold 103b: Lower mold 105: Sprue

Claims (10)

A casting wash composition for use in applying to a surface of a mold made using a refractory aggregate and an inorganic binder, comprising:
A casting mold wash composition comprising: a water-soluble base (A) having a boiling point of 200° C. or higher; and water; and a content of inorganic particles in the casting mold wash composition is 2 mass% or less based on the total amount of the casting mold wash composition. The casting wash composition according to claim 1, wherein the viscosity of the casting wash composition is 0.5 mPa·s or more and 1200 mPa·s or less. The casting wash composition according to claim 1 or 2, wherein the water-soluble base (A) contains one or more selected from the group consisting of polyhydric alcohols, polystyrene sulfonates, naphthalene sulfonic acid-formaldehyde condensates, and polyacrylic acids. A method for manufacturing a casting using a mold manufactured using a refractory aggregate and an inorganic binder, comprising the steps of:
applying a casting wash composition to a surface of the mold;
pouring a metal material into the mold having the casting wash composition applied to its surface to obtain a casting;
having
The casting mold wash composition contains a water-soluble base (A) having a boiling point of 200° C. or more and water, and the content of inorganic particles is 2 mass% or less based on the total amount of the casting mold wash composition. In the step of applying the casting wash composition,
The method for producing a casting according to claim 4, further comprising applying the mold wash composition for casting or immersing the mold in the mold wash composition for casting. In the step of applying the casting wash composition,
The method for producing a casting according to claim 4 or 5, wherein the surface temperature of the mold is 100°C or higher. In the step of applying the casting wash composition,
7. The method for producing a casting according to claim 4, wherein the metallic material is a non-ferrous alloy. A method for suppressing sand adhesion to a casting obtained by using a mold manufactured by using a refractory aggregate and an inorganic binder, comprising the steps of:
applying a casting wash composition to a surface of the mold;
pouring a metal material into the mold having the casting wash composition applied to its surface to obtain a casting;
having
The casting mold wash composition contains a water-soluble base (A) having a boiling point of 200°C or more and water, and the content of inorganic particles is 2 mass% or less based on the total amount of the casting mold wash composition. In the step of applying the casting wash composition,
9. The method for inhibiting sand burn-in adhesion according to claim 8, comprising coating the casting mold wash composition or immersing the mold in the casting mold wash composition. In the step of applying the casting wash composition,
The method for inhibiting sand burn-in according to claim 8 or 9, wherein the surface temperature of the mold is 100°C or higher.

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