JP3161826B2 - Release agent for wax model for precision casting and method for molding wax model - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release agent for a wax model preformed in an investment casting method, which is one of precision casting methods, and a method for molding a wax model in that case.

[0002]

2. Description of the Related Art For example, industrial parts such as golf iron heads and metal heads, aerospace related parts, OA equipment such as printer heads, and nuclear power parts require strict dimensional accuracy and production efficiency, and are manufactured by a precision casting method. You.

As an industrial precision casting method, there is a method called an investment casting method or a lost wax casting method. This method is performed, for example, according to the procedure shown in FIG. That is, a step 1 for preparing a predetermined mold for each part, a step 2 for applying a release agent to the mold, a step 3 for forming a wax model according to the mold, and a step 4 for combining them into a tree. Washing the mold release agent from the tree 5, forming a shell by bringing the refractory slurry into close contact with the tree surface 6, heating the whole to remove the wax 7, firing the shell 8 to make a mold, It comprises a step 9 of casting metal into a mold and a finishing step 10 of peeling off the shell.

In the step 3 of molding a wax model, it is desired that the molding operation is performed efficiently. In general, a wax model material is used as a material for forming a wax model.
The wax-based model material contains several kinds of materials such as natural wax, synthetic wax, paraffin wax, resin, rosin, and filler. A wax model is formed by filling such a material into a mold. In order to facilitate the work of removing the wax model from the mold, a mold release agent is applied to the mold in advance. As the release agent for the wax model, fatty acid, metal soap, glycol, fluorine-based release agent, silicone-based release agent and the like are used. recent years,
As such a wax model release agent, silicone-based release agents have been receiving attention. This is easy to spread due to the low surface tension, and easily penetrates into complex details. Moreover, it has the feature that it has excellent mold release properties and heat resistance.

[0005] The silicone release agent may be used as a single oil, or in the form of a solution or an emulsion. In practice, most are used in the form of a single oil. When applying to a mold, it is often used in an aerosol form.

In the case of a silicone release agent, it is originally hydrophobic, and if it remains on the surface of the wax model, the adhesion of the refractory slurry in step 6 of forming the shell deteriorates. Therefore, when a silicone-based release agent is used, a step 5 of washing the release agent from the tree is always performed before the step 6 of forming the shell.

An organic solvent is used to wash away the silicone release agent. In this case, examples of the organic solvent include toluene, xylene, petroleum ether, methylene chloride, trichloroethylene, and chlorofluorocarbon 12. Each of these organic solvents deteriorates the working environment, has a bad influence on the global environment, and is not desirable to use.

In order to solve these problems, a method has been attempted in which the silicone-based release agent is made into an emulsion type and is washed away with water without using an organic solvent. However, the emulsion may rust the mold.
Moreover, the evaporation rate of water is low, and the work efficiency is lower than in the case where an organic solvent is used. Emulsion type has a problem that it is difficult to carry out it industrially efficiently.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and substantially eliminates the need for a washing step in molding a wax model in the investment casting method of precision casting. It is an object of the present invention to provide a silicone-based release agent and a method for molding a wax model that can omit a step of washing the release agent.

[0010]

The release agent of the wax model for precision casting of the present invention is a solventless type and contains a water-soluble organopolysiloxane having a polyether group in a side chain as an active ingredient.

The water-soluble organopolysiloxane having a polyether group in the side chain is represented by the following formula 1.

[0012]

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In the above formula, m and n are 1 ≦ n ≦ 50, 10 ≦
It is an integer satisfying m + n ≦ 200. When n is smaller than 1, the hydrophilicity decreases, which is not preferable. If it is more than 50, the releasability is undesirably reduced. If m + n is smaller than 10, the object of the present invention cannot be sufficiently achieved. m + n is 200
Exceeding the viscosity increases the workability, which is not preferred. G is a group represented by Formula 2.

-R ¹ -O- (C ₂ H ₄ O) _p- (C ₃ H ₆ O) _q -A (2) wherein R ¹ is a C ₂ -C ₈ divalent carbonized Hydrogen group, A is C
₁ is an alkyl group or a carbonyl group -C _8. From the viewpoint of hydrophilicity and releasability, p and q are 8 ≦ p ≦ 30 and 10 ≦ p
Any integer that satisfies + q ≦ 100 may be used.

As the organopolysiloxane represented by the above formula 1, for example, an organopolysiloxane represented by the following formula 3 can be mentioned.

[0016]

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Conventionally, the above-mentioned organopolysiloxane has already been used in cosmetics and toiletries, for example, and is available.

In the method for molding a wax model for precision casting according to the present invention, a mold release agent is applied to a mold surface, and the wax is filled to form a wax model.
A wax model release agent containing an organopolysiloxane as an active ingredient represented by formula (1) is used.

In the step of applying the release agent to the mold surface,
Spray application with an aerosol may increase efficiency. The mold may be a commonly used mold, and the uniformity of the wax model release agent coating on the application surface may be visually confirmed.

As the wax to be filled in the mold, for example,
Preferred are wax model materials in which several or more materials such as natural wax, synthetic wax, paraffin wax, and other materials such as resin, rosin, hardened oil, and filler are blended.

When the wax model is molded, a shell is formed there. The shell is made by assembling a wax model to form a tree, and applying a refractory slurry to the surface of the assembled tree. The refractory slurry may be either a polar material or a non-polar material, but a non-polar material is more desirable from the viewpoint of wettability to a wax model. Specifically, a refractory slurry obtained by adding zircon flour, fused silica flour, or a mixture thereof to colloidal silica sol is preferable.

[0022]

The wax release agent for precision casting of the present invention is essentially moderately water-soluble. Immediately proceeding to the shell molding process without washing off the wax model surface, the wax model release agent remaining on the wax model surface improves the adhesion and affinity between the wax model and the refractory slurry. In addition, the refractory slurry is easily applied to the wax model surface. A complicated cleaning step of the release agent can be omitted, and the production efficiency is improved.

[0023]

As described above, according to the present invention, a washing step using an organic solvent can be omitted in precision casting. This not only eliminates the need for one complicated process, but also helps prevent the working environment and the global environment from deteriorating.

[0024]

Embodiments of the present invention will be described below.

Example 1 An organopolysiloxane represented by the following formula 3 was spray-coated on a predetermined mold. Room temperature is 24 ° C, mold temperature is 2
5 ° C.

[0026]

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A wax having the composition shown in Table 1 was prepared, heated to 55 ° C., filled into the above-mentioned mold, molded, and left for 12 hours after releasing. A wax model having dimensions of 120 × 40 × 10 (mm) was obtained.

[0028]

Table 1 Beeswax 15% by weight Paraffin wax 35% by weight Gum-rosin 20% by weight Hardened oil 30% by weight The surface of the obtained wax model is coated with a refractory slurry composed of colloidal silica sol and Jilluron flour. The state of adhesion was visually checked. It was found that the refractory slurry was completely adhered.

In the same manner, four wax models were successively produced, and a refractory slurry was applied to each of the wax models in the same manner, and the condition was visually checked. In each case, it was found that the refractory slurry was completely adhered.

Next, a refractory slurry comprising a colloidal silica sol and a mullite flour was further overlaid on the surface of the refractory slurry containing zircon flour several times according to a usual method. Next, the refractory slurry covering the wax model surface was dried and dewaxed, and a predetermined metal material was cast to obtain a cast product.

The dimensions of the cast product were accurate and free from surface defects, and the appearance was not different from the conventional product.

From the above, when the organopolysiloxane represented by the formula 3 is used as a mold release agent, a washing step is not required, the mold release of the wax model from the mold is improved, and the wax model and the refractory material slurry are used. It has been found that an excellent total effect is brought about in precision casting, such as an improvement in the affinity between them.

Comparative Example 1 The procedure of Example 1 was repeated except that an emulsion-type silicone release agent “Shin-Etsu Chemical Silicone Release Agent KM-722” was used as the release agent.

Since the release agent was not washed off, it was confirmed that the refractory slurry was hard to adhere to the wax model.

[Brief description of the drawings]

FIG. 1 is a view showing a production process of a conventional ordinary investment casting.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-84643 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22C 3/00 C09D 183/12

Claims (4)

(57) [Claims] 1. A release agent for a wax model for precision casting, comprising a water-soluble organopolysiloxane having a polyether group in a side chain as an active ingredient. 2. The water-soluble organopolysiloxane having a polyether group is represented by the following formula 1. (In the above formula, m and n are 1 ≦ n ≦ 50, 10 ≦ m + n ≦ 2
G is an integer satisfying 00, G is a group represented by the formula 2-R ¹ -O- (C ₂ H ₄ O) _p- (C ₃ H ₆ O) _q -A (2), and R ¹ is C divalent hydrocarbon group having ₂ -C _8, a is a carbonyl group or an alkyl group of _C 1 -C _8,
2. The release agent for a wax model for precision casting according to claim 1, wherein p and q are organopolysiloxanes represented by the following formula: 8 ≦ p ≦ 30, 10 ≦ p + q ≦ 100). Wherein by applying a release agent to the mold surface, when filled with wax molding a wax model, the side chain as a release agent
A method for molding a wax model for precision casting, comprising using a release agent containing a water-soluble organopolysiloxane having a polyether group as an active ingredient. 4. The water-soluble organopolysiloxane having a polyether group is represented by the following formula 1. (In the above formula, m and n are 1 ≦ n ≦ 50, 10 ≦ m + n ≦ 2
Integer satisfying 00, G is _-O- Formula _{^{2 -R 1 (C 2 H 4}} O) p - a group represented by _{(C 3 H 6 O) q} -A ··· (2), R 1 Is a C _{2 to} C ₈ divalent hydrocarbon group, A is a carbonyl group or a C _{1 to} C ₈ alkyl group, and p and q are each an integer satisfying 8 ≦ p ≦ 30 and 10 ≦ p + q ≦ 100) The method for molding a wax model for precision casting according to claim 3, wherein the wax model is an organopolysiloxane.