JPH08155586A - Prototype casting mold wax and production of precision casting - Google Patents

Abstract

PURPOSE: To completely remove wax by heating for a short time by using a vinyl based polymer having a repeating structure contg. the unit structures of formula I and formula II at specific amt. as a wax material for a prototype casting mold. CONSTITUTION: The vinyl based polymer having at least one among the repeating units expressed by the formula I and the formula II within a range of 50 to 100wt.% is used as the wax material. R<1> is H or CH<3> . R<2> is 15 to 30C aliphat. hydrocarbon group. B is the structure of formula III. R<4> and R<5> are respective H or 1 to 30C aliphat. hydrocarbon groups. At least either of R<4> and R<5> are 15 to 30C aliphat. hydrocarbon groups. This vinyl based polymer has sufficient strength and a relatively low m. p. The viscosity thereof falls sharply at about the m.p. The polymer is easily removable by slight heating and its residues are extremely little.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prototype mold wax and a method for producing a precision casting product using the prototype mold wax. More specifically, it relates to a lost wax casting method and a method for producing a prototype mold wax and a precision casting product useful for improving productivity and quality of precision casting products by electroforming.

[0002]

2. Description of the Related Art Lost wax casting, electroforming and the like are well known techniques with a long history as a method for producing precision cast products using a prototype wax.

The lost wax casting method is a wax laminating system, computer-controlled cutting, casting into a resin mold such as silicone rubber, and drawing of flat plate wax into a prototype mold and a refractory such as gypsum. After embedding in the slurry and drying and hardening the refractory slurry, the prototype mold wax is removed through a heat dewaxing process to create a mold, and the molten metal is poured into the space of this mold and cooled and solidified, then the refractory It is a method of breaking a mold and taking out a metal product.

In the conventional lost wax casting method, the prototype mold wax used is mainly waxes typified by paraffin wax and carnauba wax, and ethylene is appropriately selected in view of dimensional accuracy, strength and thermal properties to be applied. -A vinyl acetate alcohol copolymer (EVA), a resin having a hot-melt property such as a petroleum resin, an additive such as rosin and stearic acid amide, and in some cases an additive such as talc.

In the conventional dewaxing process in the lost wax casting method, the refractory hardened material in which the prototype mold wax is embedded is heated to a temperature higher than the melting temperature of the wax to melt and remove the prototype mold wax, and further heated to burn or heat the residual wax. The wax is decomposed and the wax is completely removed. During this heating, the mold must be gradually heated for a long time in order to prevent the mold from breaking due to thermal expansion of the original mold wax, and to prevent contamination and clogging of the inner wall of the mold due to carbonization of the residual wax, etc. It is impossible to eradicate the inconveniences such as the destruction of steel, the inclusion of air bubbles in the finished casting, and the poor surface condition. Therefore, it is undeniable that the productivity is further lowered when obtaining a more precise cast product.

On the other hand, the electroforming method is a method in which a prototype mold made of a preformed low melting point alloy is plated, then the low melting point alloy is removed by heat melting or caustic soda, and the plated portion is taken out as a product. .

However, in this method, since a low melting point alloy, aluminum or the like is used for the prototype mold, there is a problem that the raw material cost and the processing cost are increased, and it is necessary to use heating or caustic soda when removing the prototype mold. Therefore, deformation and contamination of the product have been problems.

Further, as an example of precision casting, there is manufacturing of jewelery, in which a relatively heat-resistant jewel is inserted into the stone retaining portion of the prototype mold wax, and in this state, the stone is retained through a normal casting process. A method of obtaining a cast product has been taken. This method eliminates the stone-setting step and is therefore used for products with a relatively large number of jewels and products where stone-setting is difficult. However, in the dewaxing / firing process, defects such as cracks and discoloration often occur due to exposure to high temperatures for a long time. Therefore, the dewaxing / firing time is inevitably shortened and the temperature is lowered, so that the dewaxing is not performed even in the details of the stone retaining part, which causes the poor bathing due to the obstruction of the wax.

In order to solve such a problem in heat dewaxing, JP-A-1-289537 proposes a lost wax casting method in which a prototype mold wax made of a synthetic resin is used and the prototype mold is removed by solvent extraction. ing. As the mold wax, specifically, a vinyl acetate-based resin as a main component to which a plasticizer such as diphenylphthalate and waxes such as paraffin wax are added is disclosed.

However, the solvent solubility of such a prototype mold wax mainly composed of vinyl acetate resin is not sufficient, and it is difficult to remove the prototype mold wax by heat, so that the productivity and quality of the cast product are improved. The improvement was limited.

Also, in the electroforming method, Japanese Patent Laid-Open No. 63-1
In 92888, a method of electroforming using a prototype mold made of synthetic resin has been proposed. As the synthetic resin used here, specifically, a styrene resin is disclosed, and as a dissolving solvent, a chlorine solvent, methyl ethyl ketone (MEK), and dimethylformamide (DM) are disclosed.
F) is used.

However, the use of a chlorine-based solvent as a solvent has problems in terms of safety and environment,
On the other hand, sufficient solubility was not obtained with a solvent other than chlorine such as MEK and DMF. Further, when the styrene resin is used, it is difficult to remove the prototype mold wax by heat, and the productivity and quality of the cast product are limited.

From this point of view, there is a demand for a prototype mold wax that can be easily fluidized or decomposed by heating and can be easily solvent-extracted in the lost wax casting method, electroforming method, or the like.

Further, as described above, since the removal process of the prototype mold wax mainly composed of wax is conventionally carried out only by heating, a residue is liable to remain, and in the above-mentioned prior art example using the synthetic resin, it is caused by heat. Since it is difficult to remove it, it is removed only by the solvent, and it cannot be said to be efficient, and there is room for improvement in such a removal process itself.

[0015]

SUMMARY OF THE INVENTION Therefore, the present invention facilitates the improvement of the quality of the cast products and the productivity reduction such as the cost reduction in the above lost wax casting method and the electroforming method, and the production of precision cast products. The challenge is to provide the necessary technology. The present invention further provides a method for producing a prototype mold wax and a precision casting product using the prototype mold wax, which have characteristics such as easy moldability, easy removal by heat, easy removal by solvent, and little residue after removal. The challenge is to provide. Another object of the present invention is to provide a method for producing a precision cast product, which can be expected to shorten the process time and improve the quality.

[0016]

The above-mentioned problems are solved by the following general formula (1).

[0017]

Embedded image

The repeating unit represented by and the following general formula (2)

[0019]

[Chemical 6]

50 to 100% by weight, more preferably 80 to 100% by weight of at least one of the repeating units represented by
Achieved by a prototype mold wax characterized in that it comprises a vinyl polymer (I) having a range of 100% by weight.

The above-mentioned problems are solved by the following general formula (1)

[0022]

[Chemical 7]

The repeating unit represented by and the following general formula (2)

[0024]

Embedded image

50 to 100% by weight, more preferably 80 to 100% by weight of at least one of the repeating units represented by
It is also achieved by a method for producing a precision cast product, which comprises using the vinyl polymer (I) having a range of 100% by weight as a prototype mold wax.

In the above general formula (1), R ¹ ,
R ² and B are as follows.

R ¹ is H or CH ₃ . R ² is an aliphatic hydrocarbon group having 15 to 30 carbon atoms, preferably 18 to 22 carbon atoms. B is

[0028]

[Chemical 9]

It is any one of divalent groups selected from
In the display here, R ² is bonded to the right side of B above. Here, R ³ is a divalent organic group, typically an aliphatic, alicyclic or aromatic hydrocarbon group having 2 to 30 carbon atoms, preferably 2 to 6 carbon atoms.

In the above general formula (2), R ⁴ and R
⁵ is H or an aliphatic hydrocarbon group having 1 to 30 carbon atoms, more preferably an aliphatic hydrocarbon group having 1 to 22 carbon atoms, and at least one of R ⁴ and R ⁵ has a carbon number. It is an aliphatic hydrocarbon group having 15 to 30, more preferably an aliphatic hydrocarbon group having 18 to 22 carbon atoms.

The repeating unit represented by the general formula (1) is derived from a long side chain-containing vinyl-based monomer described below, and the repeating unit represented by the general formula (2) includes a long side chain containing later described. Derived from maleic acid type monomer.

Further, the present invention provides the above-mentioned method for producing a precision casting product, which includes a solvent washing step of the prototype mold wax. The present invention also provides the above-mentioned method for producing a precision cast product, wherein the solvent washing step of the prototype mold wax is performed at a temperature equal to or higher than the melting point of the prototype mold wax.

According to the method for producing a precision cast product, the above-mentioned subject also includes, as the step of removing the prototype mold wax, a step of removing the prototype mold wax by heating and a step of removing the prototype mold wax by solvent cleaning. Is also achieved.

[0034]

As described above, in the present invention, the repeating unit represented by the general formula (1) and the following general formula (2)
50 at least one of the repeating units represented by
The vinyl-based polymer (I) having a range of ˜100% by weight is used as a prototype mold wax.
Has a sufficient strength and can manufacture a prototype mold having a complicated shape. Further, since it has a relatively low melting point and the viscosity sharply decreases in the vicinity of the melting point, it can be easily removed by slight heating, and the residue becomes very small. Furthermore, since it exhibits good solubility in many commonly used organic solvents, it can be easily removed by using a solvent, and if it is removed with a solvent at a temperature above the melting point, it is extremely easy and complete. Can be removed. Therefore,
According to the method for producing a precision cast product of the present invention, the prototype mold wax can be removed easily and completely, and since there is no residue, a high quality product can be produced. Further, the productivity is improved because the yield is improved and the removal process is facilitated to reduce the cost.

Further, in the method for producing a precision casting product according to the second invention, a heating process and a solvent cleaning process are used together as a removal process of the prototype mold wax, and the residual mold wax after the melt removal is removed. Therefore, it is not necessary to further heat for a long time or at a high temperature, and there is no problem such as destruction of the refractory mold and contamination of the residual mold wax with carbides, and a high quality cast product can be obtained in a short time.

Hereinafter, the present invention will be described in more detail based on the embodiments. The vinyl polymer (I), which is an essential component constituting the prototype mold wax of the present invention, has the following general formula (1):

[0037]

[Chemical 10]

The repeating unit represented by and the following general formula (2)

[0039]

[Chemical 11]

50 to 100% by weight, preferably 80 to 100% by weight of at least one of the repeating units represented by
Have wt%. When at least one long side chain-containing repeating unit selected from the above general formulas (1) and (2) is less than the above range, there is a problem that crystallinity is lowered and it takes time to remove.

The softening temperature of the polymer (I) is 35 to 150.
C., particularly 35 to 100.degree. C. is preferable, and if it is lower than 35.degree. C., the strength of the molded body becomes insufficient, and if it is higher than 150.degree. C., workability at the time of molding may be deteriorated or it may take time to remove.
The weight average molecular weight of the polymer (I) is 1,000 to 100,
000, especially 5,000 to 50,000 is preferable.
When it is lower than 1,000, the strength of the molded body is insufficient, and 100,
If it is higher than 000, removal may take a long time.

The method for producing the polymer (I) used in the present invention will be described below. The polymer (I) has the following general formula (3):

[0043]

[Chemical 12]

A long side chain-containing vinyl monomer (A
-1) and the following general formula (4)

[0045]

[Chemical 13]

Polymerizing a monomer component containing at least one long side chain-containing monomer (A) selected from the long side chain-containing maleic acid monomers (A-2) represented by Made by.

The long side chain-containing vinyl monomer (A-1)
As, for example, stearyl (meth) acrylate,
(Meth) acrylic acid higher alkyl esters, which are esters of (meth) acrylic acid such as behenyl (meth) acrylate and a C _{15 to} C ₃₀ higher alcohol; monobasic linear fatty acids such as stearic acid and (meth ) Addition product of a polymerizable monomer capable of addition reaction with a carboxyl group such as glycidyl acrylate or isopropenyloxazoline; fatty acid (mixed fatty acid) of vegetable oil such as coconut oil and polymerization capable of addition reaction with a carboxyl group as described above Additives with a polymerizable monomer;
Addition products of higher alcohols such as stearyl alcohol and oleyl alcohol, polyvalent isocyanate compounds, and polymerizable monomers having a hydroxyl group such as hydroxyethyl (meth) acrylate; higher fatty acid vinyl esters such as vinyl stearate. be able to. Of these, stearyl (meth) acrylate is particularly preferable.

The long side chain-containing maleic acid-based monomer (A-
The 2), for example, stearyl maleate, behenyl maleate, higher alkyl malate such C ₁₅ -C _30, such as distearyl maleate; stearyl fumarate, behenyl fumarate, C _15, such as distearyl fumarate - Examples thereof include C ₃₀ higher alkyl fumarates.
Of these, stearyl maleate is particularly preferable.

The polymerizable monomer (B) other than the long side chain-containing monomers (A-1) and (A-2) used for the synthesis of the polymer (I) is not particularly limited, and examples thereof include styrene,
Styrene derivatives such as vinyltoluene, α-methylstyrene and chloromethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, dodecyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid such as 2-ethylhexyl and C _1-
(Meth) acrylic acid esters synthesized by esterification with C ₁₄ monoalcohol; (meth) acrylic acid,
Unsaturated carboxylic acids such as crotonic acid, maleic acid, fumaric acid, itaconic acid or their half-esters or salts thereof; (meth) acrylamide, N-monomethyl (meth) acrylamide, N-monoethyl (meth) acrylamide, N , N-dimethyl (meth) acrylamide, N
-(Meth) acrylamide derivatives such as methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide, salts thereof and quaternary compounds thereof;
Unsaturated hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and monoesters of (meth) acrylic acid and polypropylene glycol or polyethylene glycol; (meth) Sulfonic acid group-containing unsaturated monomers such as ethyl acrylate-2-sulfonic acid, vinyl sulfonic acid, styrene sulfonic acid, and salts thereof; dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) Acrylamide, dimethylaminopropyl (meth) acrylamide, vinyl pyridine,
Basic unsaturated monomers such as vinylimidazole and vinylpyrrolidone; (meth) acrylic acid and ethylene glycol, 1,3-butylene glycol, diethylene glycol, 1,6-hexane glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol , Trimethylolpropane, pentaerythritol, dipentaerythritol, and other polyhydric alcohols, and other polyfunctional (meth) acrylic acid esters having two or more polymerizable unsaturated groups in the molecule; vinyltrimethoxysilane, γ -(Meth) acryloylpropyltrimethoxysilane, allyltriethoxysilane, trimethoxysilylpropylallylamine and other organosilicon group-containing unsaturated monomers; 2-isopropenyl-2-oxazoline, 2-vinyloxazo Oxazoline group-containing polymerizable monomers such as styrene; epoxy group-containing polymerizable monomers such as glycidyl (meth) acrylate and acrylglycidyl ether; vinyl fluoride, vinylidene fluoride, vinyl chloride, vinylidene chloride, etc. Halogenated unsaturated monomer; halohydrin group-containing unsaturated monomers such as (meth) acrylic acid 2-hydroxy-3-chloropropylene; and aziridinyl group-containing (meth) acrylic acid-2-aziridinylethyl Polymerizable monomer; Blocked isocyanate group-containing unsaturated monomer such as reaction adduct of (meth) acrylic acid-2-isocyanatoethyl and ethyl alcohol; Ethylenic unsaturated such as divinylbenzene and diallyl phthalate Unsaturated monomers having two groups; vinyl esters of saturated carboxylic acids such as vinyl acetate; Lilonitrile; and acrolein, etc. may be mentioned, and any one of them may be used alone or two or more thereof may be mixed and used.

Polymerization can be carried out by radical polymerization, ionic polymerization or the like, and any polymerization method such as bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization can be used. The polymer (I) is a solution or solid in which the polymer (I) is dissolved, a suspension in which solid particles of the polymer (I) are dispersed in a medium, or solution particles of the polymer (I) is in a medium. To obtain an emulsified liquid. By removing volatile components such as unreacted monomers and solvents from these reaction mixtures, the solid polymer (I) is obtained. Further, the polymer (I) can be produced in any polymerization form such as block, graft and random.

However, as a method for synthesizing the polymer (I), a radical polymerization method using a radical polymerization initiator is preferable. As the radical polymerization initiator, any conventionally known one may be used, and either an oil-soluble one or a water-soluble one may be used. Examples of the oil-soluble initiator include azobisisobutyronitrile, azobisvaleronitrile, 2,2'-azobis- (2,4-dimethylvaleronitrile), 1,1'-azobis- (cyclohexane-1-). Azo compounds such as carbonitrile), 2,2′-azobis- (2-aminopropane) dihydrochloride, 4,4′-azobis- (4-cyanopentanoic acid); benzoyl peroxide, cumene hydroperoxide, Examples thereof include organic peroxides such as di-t-butyl peroxide, t-butyl hydroperoxide and t-butylperoxy-2-ethylhexanoate. Examples of the water-soluble initiator include potassium persulfate, ammonium persulfate, hydrogen peroxide and the like. In addition, in order to increase the polymerization rate, an oxidizing agent type polymerization initiator may be used as a redox type initiator in combination with a reducing agent, if necessary. The amount of the polymerization initiator used is 0.1 parts by weight based on 100 parts by weight of the polymerizable monomer component.
It is in the range of 01 to 5 parts by weight. The radical polymerization initiator can be added at an appropriate time as in the case of ordinary radical polymerization. As a polymerization apparatus used for radical polymerization of the polymerizable monomer component, a conventionally known apparatus can be applied. The polymerization temperature is 0 to 200 ° C., preferably 5
The polymerization time is 0 to 150 ° C., and the polymerization time is 1 to 15 hours.

In the prototype mold wax of the present invention, if necessary, rosin, amine stearate, various metal powders or non-metal inorganic powders such as talc in view of dimensional accuracy, strength and thermal properties to be applied. It is also possible to add such as.

The method of producing a precision cast product of the present invention is characterized by using the prototype mold wax made of the polymer (I) as described above. The lost wax casting method as one embodiment thereof is performed as follows, for example.

That is, first, a conventionally known wax laminating system, computer controlled cutting,
By applying a method such as pouring into a resin mold of silicone rubber or the like, drawing a flat plate wax, etc., a prototype mold is produced using the prototype mold wax composed of the polymer (I).

Next, the prototype mold thus formed is embedded in a refractory slurry, or the prototype mold is dip-coated in the refractory slurry, and the refractory slurry is dried and cured to form a mold.

As the mold material of the refractory material, conventionally known materials can be used, and for example, gypsum or a mixture of refractory powder and a refractory liquid binder as described below can be used. As the refractory powder, zircon (ZrO ₂
・ SiO ₂ ), fused quartz (amorphous SiO ₂ ), fused alumina (amorphous Al ₂ O ₃ ), sillimanite (hardened by heating clay), etc. has a high degree of fire resistance and a small amount of expansion due to heating. Powders of substances are mentioned. The liquid binder is
When water is added, hydrolysis occurs to form a jelly-like sol, which condenses with time to form a solid gel, and an organic silicon compound such as ethyl silicate is used. The organic silicon compound is completely solidified by firing to be silicic acid (SiO ₂ ), which adheres to the refractory powder in the vicinity to form a hard mold.

In the case of coating, the coating operation may be repeated not only once but also several times. Since the molten metal comes into contact with the first layer in a later step, the refractory powder is particularly fine, for example, a particle size of 325 to 325.
400 mesh is preferable, and an aspect is also desired in which the amount of the mixture is increased to increase the viscosity and adhere well. A stuccoing operation may be performed to sprinkle the same coarse refractory powder on the outer surface of the pulled up material after the first coating. Then, it is dried at room temperature for a while, and then the next layer is coated, stuccoed, and dried several times to increase the thickness to form a shell-shaped mold. Alternatively, it is also possible to use an investment method in which coating is stopped about twice, the coating is cured in a frame, and the periphery thereof is filled with a slurry of the same quality to form a mold.

Next, the prototype mold wax is removed to obtain a precision casting mold. The method for removing the prototype mold wax is not particularly limited, but since the prototype mold wax composed of the polymer (I) exhibits good solubility in various solvents as described above, it can be washed with a solvent. It is desirable to remove the polymer (I) with a solvent heated to a temperature equal to or higher than the melting point Tm of the polymer (I), for example, a temperature of about Tm to (Tm + 50) ° C. When the solvent cleaning is performed in this way, there is substantially no residual mold wax, and it is not necessary to add a step of burning or pyrolyzing the mold wax by heating it to a high temperature for a long time after that, and the residual mold wax. There is no fear that the inner wall surface of the mold will be contaminated or clogged due to carbonization of wax. Examples of the solvent that can be used to dissolve and remove the prototype mold wax composed of the polymer (I) include aromatic solvents such as benzene, toluene and xylene, aliphatic solvents such as hexane, decalin and tetralin, and tetrahydrofuran. And the like. Of these, toluene, hexane, decalin and the like are preferable.

Of course, it is also possible to remove the original mold wax by heating. The prototype mold wax made of the polymer (I) has characteristics such as low melting point and high crystallinity, and can be easily removed by only slightly heating and leaving almost no residual mold wax. Similarly to the above, there is no need to gradually heat over a long period of time or heat to a high temperature as in the case of using a conventional wax.

Further, although it relates to the second invention described later, it is possible to perform both the heating step and the solvent washing step as the step of removing the prototype mold wax.

After removing the prototype mold wax in this way, it is heated and fired if necessary to obtain a refractory mold. Finally, the molten metal is poured into the space of the mold, cooled and solidified, and then the refractory mold is broken to take out the metal product.

Also in the electroforming method as another embodiment of the method for producing a precision cast product of the present invention, similar to the case of the lost wax method, injection molding or the like is performed in advance using a prototype mold wax made of the polymer (I). Producing a prototype mold by, according to the usual method, after performing alkali degreasing, chromic acid etching and chromic acid neutralization treatment as necessary, perform the pre-process such as chemical nickel plating, chemical copper plating on the outer periphery, Apply a plating process to form a plating film on the prototype mold,
After that, the prototype mold wax made of the polymer (I) can be removed by the above-described removal operation, and the plated portion can be taken out as a product.

The method for producing a precision cast product of the present invention is not limited to the lost wax method and the electroforming method as described above, and the prototype mold wax made of the polymer (I) as described above is used. It is also applicable to methods other than those that can be used, and in that case, a prototype mold wax composed of the polymer (I) is used, or a method as described above is used as a step for removing the prototype mold wax. Other than the above, it can be carried out according to the usual method.

Next, a method for manufacturing a precision cast product according to the second invention will be described. The precision casting product manufacturing method of the second invention is
The step of removing the original mold wax is characterized by including a step of removing the original mold wax by heating and a step of removing the original mold wax by solvent cleaning. In addition, as a process sequence, it is desirable that most of the original mold wax is first removed by heating and then the residual mold wax is removed by solvent cleaning. In the precision casting product manufacturing method of the second invention, the steps other than the removal of the prototype mold wax are not particularly limited, and as described in the explanation of the precision casting product manufacturing method according to the first invention. The conventional lost wax method, electroforming method, or the like may be used. Briefly, in the lost wax method, first, the prototype mold formed by the prototype mold wax is embedded in the refractory slurry, or the prototype mold is dip-coated in the refractory slurry, and the refractory slurry is dried and cured. After forming the mold, part of the prototype mold wax is removed by heating, followed by washing with an organic solvent and complete dewaxing, and then, if necessary, heating and firing to obtain a refractory mold, and finally this mold The molten metal is poured into the space, cooled and solidified, and then the refractory mold is broken to take out the metal product. Further, in the electroforming method, a prototype mold obtained by applying conductivity to the surface using a prototype mold wax instead of the conventionally used low melting point alloy is produced, and after the surface is electroplated, it is heated. After removing a part of the original mold wax, a step of completely dewaxing by washing with an organic solvent is taken.

Conventionally, after melting and removing the original mold wax, the remaining mold wax was burned or pyrolyzed to completely remove the mold wax, but the mold wax was destroyed or the residual mold wax was removed. In order to prevent the inner wall of the mold from being contaminated or clogged due to carbonization or the like, it has to be gradually heated over a long period of time, and it takes time to produce a cast product, which easily causes problems in productivity and quality. However, in the second aspect of the present invention, as described above, as the step of removing the prototype mold wax,
By using the removal process by heating and the removal process by solvent washing together, it is not necessary to gradually heat for a long period of time or to heat at high temperature, and there are problems such as destruction of the refractory mold and contamination of the residual mold wax with carbide. It is essentially removable.

The prototype mold wax used in the second invention is not particularly limited as long as it can be dissolved in an organic solvent at room temperature or under heating. For example, conventionally used paraffin wax, Natural waxes such as carnauba wax and montana wax, polyethylene wax and its graft products, synthetic waxes such as stearic acid amide, EVA, petroleum-based resins and other resins having hot-melt properties are used alone or as a mixture of two or more thereof. It is also possible. However, a vinyl polymer or a mixture of the vinyl polymer and the above compound is preferable in view of solubility in an organic solvent, and further, in view of better solubility and strength, the polymer according to the first invention (I Prototype waxes containing) are preferred. It is possible to add rosin, amine stearate, various metal powders, or non-metal inorganic powders such as talc, if necessary, in view of the dimensional accuracy, strength, and thermal properties to be applied.

In the second aspect of the present invention, the heating step for removing the prototype mold wax may be such that the prototype mold wax to be used can be removed by softening, melting, and depends on the type of the prototype mold wax. However, the melting point of the prototype mold wax is Tm
, Tm to (Tm + 5
0) a temperature of about 0 ° C., or assuming that the prototype mold wax does not have a melting point but has a softening point Ts, for example, Ts to
The temperature is about (Ts + 50) ° C. The heating temperature is
This is because if it is much higher than (Tm + 50) ° C. or (Ts + 50) ° C., problems such as destruction of the refractory mold and contamination due to carbonization of the original mold wax may occur. Further, when this heating step is first performed as the removal step of the prototype mold wax, the removal of the prototype mold wax in this heating step is not particularly limited and depends on the conditions of the subsequent solvent cleaning step. The proportion of about 60 to 95% of the total weight of the prototype mold is desired for complete and rapid dewaxing in combination with the subsequent solvent washing step.

On the other hand, the solvent washing step as the step of removing the prototype mold wax is not particularly limited as long as it uses an organic solvent exhibiting a good solubility in the prototype mold wax, and it is at room temperature (2
5 ° C. ± 5 ° C.), a mode using an organic solvent, a mode using ultrasonic vibration operation, a physical cleaning promoting operation such as jet spraying, a mode using an organic solvent under heating conditions, etc.
In a more preferred embodiment, the temperature of the melting point or softening point of the prototype mold wax that does not lead to thermal decomposition or combustion of the prototype mold wax, for example, Tm to (Tm + 50) ° C. or Ts to
It is desired to wash the organic solvent under a temperature condition of about (Ts + 50) ° C. The organic solvent used in such a solvent washing step is generally commercially available, as long as it shows solubility in the prototype mold wax used, for example, aliphatic hydrocarbons and aromatic hydrocarbons. , Halogenated hydrocarbons, alcohols, ketones, esters, ethers and the like can be used, and can be appropriately selected in consideration of affinity with the prototype mold wax used, handleability and the like.

In the precision casting product manufacturing method according to the second aspect of the present invention as described above, the total process time is shortened, and long-term or high-temperature heat treatment is not required for dewaxing, and there is a risk of product contamination due to the residue of the prototype mold wax. It has the advantage that it does not occur, and can be suitably applied to the production of various precision cast products that have been produced by the lost wax method, electroforming method, or the like. For example, when manufacturing jewelery as described above (wax stone retaining method), after inserting the gem into the stone retaining portion of the prototype mold wax, the buried prototype mold wax is heated to the melting point or higher, and the organic solvent is injected from the sprue. Alternatively, the prototype mold wax may be completely removed by immersing the prototype mold in an organic solvent, and then the firing process may be followed by heating to the casting temperature to perform casting. Since it can be waxed, it can be cast without exposing the gem to a high temperature condition for a long time, and it reduces defects such as cracks and discoloration of the gem, and improves the gloss and smoothness of the surface of the gem, making it possible to manufacture more precise cast products. It will be possible.

[0070]

EXAMPLES Examples of the present invention and comparative examples outside the scope of the present invention will be shown below, but the present invention is not limited to the following examples.

Reference Example 1 A flask equipped with a dropping funnel, a stirrer, a nitrogen introducing tube, a thermometer and a condenser was charged with 100 parts of toluene and heated to 80 ° C. while slowly blowing nitrogen gas under stirring. Next, stearyl acrylate 1 prepared in advance
A polymerizable monomer solution consisting of 00 parts, 200 parts of toluene and 1 part of 2,2′-azobisisobutyronitrile was dropped from an appropriate funnel over 2 hours and polymerized at 80 ° C. After completion of the dropping, aging was carried out at the same temperature for 1 hour and then under reflux for 2 hours to obtain a toluene solution having a solid content of 25.2%.
When this solution was analyzed by gas chromatography, residual monomers were not detected, and the polymerization rate was 100%. Toluene was distilled off from this solution under reduced pressure heating to obtain a white solid compound (a having a weight average molecular weight of 6000 and a melting point of 45 ° C.).
-1) was obtained.

Reference Example 2 A flask similar to that of Reference Example 1 was charged with 33 parts of toluene and stirred at 80 ° C. while slowly blowing nitrogen gas.
Heated to. Next, 100 parts of stearyl methacrylate, 33 parts of toluene and 2,2'-, which were prepared in advance, were prepared.
A polymerizable monomer solution consisting of 0.4 part of azobisisobutyrylonitrile was added dropwise from the funnel over 2 hours at 80 ° C.
Polymerized in. After completion of the dropping, aging was carried out at the same temperature for 1 hour and then under reflux for 2 hours to obtain a toluene solution having a solid content of 60.0%. When this solution was analyzed, the polymerization rate was 1
00%. Toluene was distilled off from this solution under reduced pressure heating to obtain a white solid compound (a-2) having a weight average molecular weight of 47,000 and a melting point of 37 ° C.

Reference Example 3 A flask similar to that of Reference Example 1 was charged with 33 parts of toluene and stirred at 80 ° C. while slowly blowing nitrogen gas.
Heated to. Next, a previously prepared polymerizable monomer consisting of 80 parts of stearyl acrylate, 15 parts of behenyl acrylate, 5 parts of styrene, 33 parts of toluene and 0.4 parts of 2,2′-azobisisobutyronitrile. The solution was dropped from an appropriate funnel over 2 hours and polymerized at 80 ° C. After completion of the dropping, the mixture was aged at the same temperature for 1 hour and then under reflux for 2 hours to obtain a toluene solution having a solid content of 60.2%.
When this solution was analyzed, the polymerization rate was 100%. Toluene was distilled off from this solution under reduced pressure heating to obtain a white solid compound (a-3) having a weight average molecular weight of 50,000 and a melting point of 50 ° C.

Reference Example 4 A flask similar to that of Reference Example 1 was charged with 33 parts of toluene and stirred at 80 ° C. while slowly blowing nitrogen gas.
Heated to. Next, 80 parts of stearyl acrylate, 15 parts of stearyl maleate, 5 parts of styrene, 33 parts of toluene, and 0.4 parts of 2,2'-azobisisobutyrolonitrile prepared in advance were prepared as a polymerizable monomer. The body solution was dropped from the appropriate funnel over 2 hours and polymerized at 80 ° C. After completion of the dropping, aging was carried out at the same temperature for 1 hour and then under reflux for 2 hours to obtain a toluene solution having a solid content of 60.0%.
When this solution was analyzed, the polymerization rate was 100%. Toluene was distilled off from this solution under reduced pressure heating to obtain a white solid compound (a-4) having a weight average molecular weight of 42,000 and a melting point of 51 ° C.

Comparative Reference Example 1 A flask similar to that of Reference Example 1 was charged with 33 parts of toluene and stirred at 80 ° C. while gently blowing nitrogen gas.
Heated to. Next, a previously prepared polymerizable monomer solution consisting of 35 parts of stearyl acrylate, 65 parts of styrene, 33 parts of toluene, and 0.4 part of 2,2′-azobisisobutyronitrile was put in a suitable funnel. Then, the mixture was added dropwise over 2 hours and polymerized at 80 ° C. After the completion of the dropping, the mixture was aged at the same temperature for 1 hour to give 2,2'-azobisisobutyrylnitrile.
An initiator solution consisting of 2 parts and 4 parts of toluene was added. Then, the mixture was aged under reflux for 2 hours to obtain a toluene solution having a solid content of 60.0%. When this solution was analyzed, 0.4% of styrene was detected and the polymerization rate was 99.6%.
Toluene and residual styrene were distilled off from this solution under reduced pressure heating to obtain a transparent solid comparative compound (b-1) having a weight average molecular weight of 68,000 and a melting point of 30 ° C.

Example 1 Using the compound (a-1) obtained in Reference Example 1 as a prototype mold wax, 10 prototype molds for precious metal jewelry products were produced by a wax laminating system, and molded in this manner. Each of the prototype molds was embedded in gypsum, dried and cured, and then the prototype mold wax was heated to 100 ° C. to give the compound (a-
Melt and discharge 1), then pour organic solvent from the sprue, 3
The process of dipping for a minute and pouring in a new solvent was repeated twice. The organic solvent used was hexane heated to 65 ° C. Casting was performed by pouring silver into the gypsum mold thus obtained. When the appearance of each of the obtained cast products was examined, no adhesion of carbides or the like was found on the surface, and the smoothness of the surface was also very good. No defects such as breakage of the gypsum mold in the dewaxing process were observed.

Example 2 Using the compound (a-2) obtained in Reference Example 2 as a prototype mold wax, five prototype molds for precious metal jewelry products were prepared by computer-controlled cutting, and molded in this manner. After embedding each of the above original molds in plaster and curing them by drying, first, heat up to 100 ° C. at 3 ° C./min, and
Hold for 0 minutes to melt and discharge the original mold wax, then pour organic solvent from the sprue and soak for 3 minutes to discharge the liquid.
Repeated times to remove residual mold wax. The organic solvent used was toluene heated to 70 ° C. Casting was performed by pouring silver into the gypsum mold thus obtained. When the appearance of each of the obtained castings was examined, the surface condition was good. No defects such as breakage of the plaster mold in the dewaxing process were observed.

Example 3 To 100 parts by weight of the compound (a-3) obtained in Reference Example 40 was added 40 parts of copper powder and the mixture was uniformly mixed in a molten state to obtain a prototype mold wax, which was made of silicone rubber. After casting into a mold to prepare a prototype mold and forming a gold plating layer having a thickness of 0.1 mm by electroplating, the prototype mold wax is heated and immersed in an organic solvent to reduce the internal compound (a-3). Removed from the hole. The organic solvent used was toluene, 80
The thing heated at 0 degreeC was used, and the immersion time was made into 2 hours. When the appearance and the inside of the obtained cast product were examined, no adhesion of carbides was found, and the surface smoothness was also very good. Incidentally. No defects such as deformation or breakage of the electroformed plating layer were observed in the dewaxing process.

Example 4 Using the compound (a-4) obtained in Reference Example 4 as a prototype mold wax, the molten prototype mold wax was poured into a silicone rubber mold to prepare a prototype mold, and electroless plating was performed. After forming the copper plating layer, a gold plating layer having a thickness of about 0.1 mm was formed by electroplating. After that, the prototype mold wax is heated and immersed in an organic solvent, and the compound (a
-4) was removed. The organic solvent used is toluene,
The thing heated at 80 degreeC was used, and the immersion time was made into 2 hours. When the appearance and the inside of the obtained cast product were examined, no adhesion of carbides was found, and the surface smoothness was also very good. Incidentally. No defects such as deformation or breakage of the electroformed plating layer were observed in the dewaxing process.

Comparative Example 1 Casting was performed in the same manner as in Example 1 except that the comparative compound (b-1) obtained in Comparative Reference Example 1 was used as a prototype mold wax. When the appearance of the five cast products obtained was examined,
In both cases, the surface had irregularities to a considerable extent and the smoothness was poor.

Comparative Example 2 Casting was performed in the same manner as in Example 2 except that the comparative compound (b-1) obtained in Comparative Reference Example 1 was used as a prototype mold wax. When the appearance of the five cast products obtained was examined,
In both cases, the surface had irregularities to a considerable extent and the smoothness was poor.

Comparative Example 3 Electroforming was carried out in the same manner as in Example 3 except that the comparative compound (b-1) obtained in Comparative Reference Example 1 was used as a prototype mold wax. When the appearance of the five electroformed products obtained was examined,
The appearance and surface properties were inferior to those of the original mold wax.

Comparative Example 4 Electroforming was performed in the same manner as in Example 4 except that the comparative compound (b-1) obtained in Comparative Reference Example 1 was used as a prototype mold wax. When the appearance of the five electroformed products obtained was examined,
The appearance and surface properties were inferior to those of the original mold wax.

Example 5 Using the compound (a-1) obtained in Reference Example 1 as a prototype mold wax, 10 prototype molds of precious metal jewelry products were produced by a wax laminating system, and molded in this manner. After embedding each of the prototype molds in gypsum and drying and curing, first heat up to 100 ° C at a temperature rising rate of 3 ° C / min and hold for 10 minutes to melt and discharge the prototype mold wax, and then to remove the solvent from the sprue. The solution was discharged by pouring for 3 minutes, and this was repeated twice to remove the residual mold wax. The organic solvent used was toluene heated to 80 ° C. Casting was performed by pouring silver into the gypsum mold thus obtained. When the appearance of each of the obtained cast products was examined, no adhesion of carbides or the like was found on the surface, and the smoothness of the surface was also very good. No defects such as breakage of the plaster mold in the dewaxing process were observed. The time required for all steps was shortened by about 1 hour as compared with Example 1.

Comparative Example 5 Commercially available paraffin wax (AC, manufactured by Car Company, USA)
CU injection wax, turquoise blue) was used as a prototype mold wax to prepare 10 prototype molds for precious metal jewelry products by a wax laminating system, and the prototype molds thus molded were each embedded in plaster and dried and cured. Then, first, at a temperature rising rate of 1 ° C / min, 7
Heat to 50 ° C, melt and discharge the prototype mold wax during this
The residual mold wax was burned off. Casting was performed by pouring silver into the gypsum mold thus obtained. When the appearance of each of the ten cast products obtained was examined, a cast was observed on the surface, and the smoothness of the surface was poor. Further, the time required for all the steps was as long as 1 hour as compared with Example 5.

[0086]

EFFECTS OF THE INVENTION Since the method for producing a precision cast product of the present invention does not require heating for a long period of time to completely remove the wax as in the conventional method, there is no shortage of contamination or clogging due to breakage of the mold or carbonization of the wax. In a short period of time, a low cost precision cast product with good yield and good quality can be obtained. Furthermore, the possibility of applying precision casting to jewelry, which was difficult in the past, has expanded.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08F 20/60 MNH 8619-4J 22/12 MMH

Claims (5)

[Claims] 1. The following general formula (1): And a repeating unit represented by the following general formula (2): 50 at least one of the repeating units represented by
Prototype mold wax comprising a vinyl-based polymer having a content of ˜100% by weight. 2. The following general formula (1): And a repeating unit represented by the following general formula (2): 50 at least one of the repeating units represented by
A method for producing precision castings, characterized in that a vinyl-based polymer having a range of ˜100% by weight is used as a prototype mold wax. 3. The method for producing a precision casting product according to claim 2, which includes a solvent washing step of the prototype mold wax. 4. The method for producing a precision cast product according to claim 2, wherein the solvent cleaning step of the prototype mold wax is performed at a temperature equal to or higher than the melting point of the prototype mold wax. 5. A method for producing a precision cast product, characterized in that the step of removing the prototype mold wax includes a step of removing the prototype mold wax by heating and a step of removing the prototype mold wax by solvent cleaning.