JP7101692B2 - Urethane-curable organic binder for molds, and cast sand compositions and molds obtained using the same. - Google Patents

Description

The present invention is an organic binder used in sand casting, particularly an organic binder for a mold used for molding a urethane-based gas-curing mold or a self-hardening mold, and casting sand obtained by using the organic binder. It relates to a composition and a mold obtained by molding such a cast sand composition.

Conventionally, as one of the typical organic molds used in sand casting, a polyol compound such as a phenol resin and a polyisocyanate compound such as diphenylmethane diisocyanate are used as a binder, and their double addition reaction (urethaneization) is performed. A urethane-based mold formed by utilizing (reaction), for example, a phenol-urethane-based mold is known. As urethane-based molds such as phenol-urethane-based molds, mass-produced gas-curing molds that do not require heating during molding and are manufactured by the amine cold box method using amine gas as a catalyst, and room temperature self-hardening. Non-mass-produced self-hardening molds manufactured by the method are widely known.

Specifically, the gas curing mold by the amine cold box method is usually for a mold composed of granular fire-resistant casting sand, a phenol resin solution using an organic solvent as a solvent, and a polyisocyanate compound solution using a mixer. After producing a cast sand composition obtained by coating the surface of such cast sand with an organic binder by kneading with an organic binder, the cast sand composition is blown into a predetermined molding die. It is manufactured by molding a mold with a metal caster, and allowing an amine-based catalyst gas to pass through the mold to cure the mold. In addition, the self-hardening mold by the room temperature self-hardening method is used when kneading granular fire-resistant casting sand with an organic binder for a mold consisting of a solution of a phenol resin using an organic solvent as a solvent and a solution of a polyisocyanate compound. It is produced by mixing a curing solvent and immediately forming the obtained mixture into a desired shape.

However, in the case of a urethane-based mold such as a phenol-urethane-based mold obtained by utilizing such a double addition reaction (urethaneization reaction) between a phenol resin and a polyisocyanate compound, air is used due to its chemical bonding characteristics. There are inherent problems of so-called moisture absorption deterioration such as hardening inhibition and strength deterioration due to the moisture inside.

Therefore, in Japanese Patent Publication No. 1-501630 (Patent Document 1), it is clear that a silane compound such as epoxysilane, aminosilane, or ureidosilane is added as a measure to prevent moisture absorption deterioration of the mold produced by the cold box method. However, even with such a silane compound, sufficient characteristics have not yet been secured, and further establishment of measures to prevent deterioration of moisture absorption has been desired.

Therefore, in Japanese Patent Application Laid-Open No. 2012-196700 (Patent Document 2), a silane compound having an isocyanate group or an acrylic compound having an isocyanate group is further combined with a polyol compound and a polyisocyanate compound to form a urethane for a mold. It has been clarified that by constructing a curable organic binder, it is possible to prevent the moisture absorption and deterioration of the mold and thus maintain excellent mold strength, but a special isocyanate group-containing compound is prepared there. I had to do it.

Further, in Japanese Patent Application Laid-Open No. 2001-205386 (Patent Document 3), a binder composition for producing a gaseous tertiary amine curable mold, which is a combination of a phenol resin, an isocyanate compound and boric acid, is clarified. Further, it has been clarified that a silane compound can be contained therein in order to improve the adhesiveness between the binder component and the aggregate. By using a binder composition containing such boric acid, the pot life is longer than that of the conventional composition for mold production, and therefore, the binder and the granular refractory aggregate are used. It is said that the strength of the mold can be maintained even if the mold is kneaded and left for several hours, but the strength of the mold is evaluated there in a dry condition where the humidity is not high. Under high humidity conditions, the mold strength was significantly reduced due to moisture absorption deterioration, making it difficult to maintain sufficient strength.

Special Table No. 1-501630 Japanese Unexamined Patent Publication No. 2012-196700 Japanese Unexamined Patent Publication No. 2001-205386

Here, the present invention has been made in the background of such circumstances, and the problem to be solved thereof is that the mold strength and its moisture absorption resistance deterioration characteristics can be improved, and the filling density is effective. It is an object of the present invention to provide a urethane-curable organic binder that can advantageously give an enhanced mold, and a urethane-curable organic binder for a mold that can effectively improve the mold strength by leaving it after molding. In addition to providing a binder, a cast sand composition that can impart excellent mold characteristics using such a urethane-curable organic binder, and a cast sand composition thereof are used for molding. , To provide a mold with excellent properties.

The present invention can be suitably carried out in various aspects as listed below in order to solve such problems. In addition, each aspect described below can be adopted in any combination, and the aspect or technical feature of the present invention is not limited to those described below, but is described in the entire specification. It should be understood that it can be recognized based on the grasped idea of invention.

(1) A urethane-curable organic binder used for molding urethane-based molds, which is a reaction product of a basic primary silane compound and hydrofluoric acid together with a polyol compound and a polyisocyanate compound, and non-hydrogenic acid. A urethane-curable organic binder for a template, which further contains a basic second silane compound as a constituent component.
(2) The template according to the above aspect (1), wherein the reaction product of the first silane compound and hydrofluoric acid is formed in advance and contained in the form of the reaction product. Urethane curable organic binder.
(3) The urethane-curable organic binder for a mold according to the above aspect (1) or the above aspect (2), wherein the polyol compound is a phenol resin.
(4) The urethane-curable organic binder for a mold according to the above aspect (3), wherein the phenol resin is an orthocresol-modified phenol resin.
(5) The reaction product is based on 100 parts by mass of the polyol compound.
The embodiment (1), characterized in that it is used in a proportion of 0.01 to 10 parts by mass.
The urethane curable mechanical binder for a mold according to any one of 1) to (4) above.
(6) The embodiment (1) to (5), wherein the second silane compound is used in a ratio of 0.01 to 10 parts by mass with respect to 100 parts by mass of the polyol compound. The urethane hardening type organic binder for a mold according to any one of the above.
(7) The urethane-curable organic for a mold according to any one of the above embodiments (1) to (6), wherein the first silane compound is an alkoxysilane containing an amino group. Caking agent.
(8) The alkoxysilane containing the amino group is 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-.
(Aminoethyl) -3-aminopropylmethyldimethoxysilane, N-
2- (Aminoethyl) -3-aminopropyltrimethoxysilane, 3-
Triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-
(Vinylbenzyl) The urethane curable organic for a mold according to the above aspect (7), which is selected from the group consisting of -2-aminoethyl-3-aminopropyltrimethoxysilane and 3-ureidopropyltrialkoxysilane. Blotting agent.
(9) The second silane compound is an epoxy silane, an isocyanate silane, or the like.
The uretan curing type for a mold according to any one of the above aspects (1) to (8), which is selected from the group consisting of chlorosilane, mercaptosilane, isocyanuratesilane, acrylic silane and methacrylicsilane. Organic binder.
(10) The reaction product of the basic first silane compound and hydrofluoric acid is
One of the above-described embodiments (1) to (9), wherein the non-basic second silan compound is contained in the polyisocyanate compound while being contained in the polyol compound. Urethane curable organic binder for molds described in.
(11) Any one of the above-mentioned embodiments (1) to (10), which further comprises at least one of an acid halide, a halogenated phosphoryl compound and a halogenated phosphine as a constituent component. Urethane curable organic binder for molds described in.
(12) A step of preparing a polyol solution obtained by dissolving a polyol compound in an organic solvent, a step of preparing a polyisocyanate solution prepared by dissolving a polyisocyanate compound in an organic solvent, and the polyol solution and / or the poly. The step of allowing the reaction product of the basic first silane compound and hydrofluoric acid to be present in the isocyanate solution, and the non-basic second silan compound in the polyol solution and / or the polyisocyanate solution. A method for preparing a uretan-curable organic binder for a template, which comprises a step of containing a uretan-curing organic binder.
(13) A casting sand composition comprising the urethane-curable organic binder for a mold according to any one of the embodiments (1) to (11) and casting sand.
(14) A mold characterized in that the cast sand composition according to the above aspect (13) is molded and cured.

As described above, in the urethane curable organic binder for molds according to the present invention, in addition to the polyol compound and polyisocyanate compound which are essential constituents thereof, the basic primary silane compound and fluoride are further added. By being configured to contain reaction products with hydrogen acid and non-basic secondary silane compounds as constituents, the strength of the mold molded using such an organic binder is improved. In particular, in addition to being able to effectively increase the leaving strength of the mold after molding, it is also possible to advantageously improve the moisture absorption and deterioration resistance characteristics of the strength of such a mold. It is.

Moreover, in the casting sand composition obtained by kneading such an organic binder for a mold according to the present invention into casting sand, the fluidity thereof can be effectively improved. In addition to being able to provide a mold with excellent fillability, it is also possible to advantageously improve the surface texture of the mold, and it is possible to provide a mold having excellent strength characteristics as described above, and such a casting. A mold molded using a sand composition has excellent mold strength, and as a mold with improved moisture absorption and deterioration resistance, a mold with improved packing density and surface texture. Therefore, it can be advantageously used in the casting process of the target metal.

In the present invention, the reaction product of the basic first silane compound and hydrofluoric acid as described above and the non-basic second silane compound are further combined with an acid halide and a phosphorylated phosphoryl. It is preferably recommended to use at least one of the compound and the halogenated phosphin in combination, whereby the above-mentioned mold strength and the moisture absorption deterioration property thereof can be further improved, and such characteristics. It is possible to exhibit the feature that the pot life of the cast sand composition obtained by kneading with the cast sand can be more effectively extended while maintaining the above.

By the way, in such a urethane curable organic binder for a mold according to the present invention, the polyol compound used as one of the main components thereof is not particularly limited, and a urethane-based curable mold has been conventionally used. Various known polyol compounds used in molding are appropriately selected and used. Specifically, phenol resin, polyether polyol, polypropylene polyol, polybutadiene polyol, polymer polyol, polypropylene glycol, polyethylene glycol, polytetramethylene ether glycol, polyoxybutylene glycol, copolymer of ethylene oxide and propylene oxide, and tetrahydrofuran. Examples thereof include a copolymer of ethylene oxide, a copolymer of tetrahydrofuran and propylene oxide, a copolymer of tetrahydrofuran and 3-methyltetrachloride, and the like.

Among them, as a polyol compound used when molding a urethane-based mold, various known phenolic resins used when molding a phenol-urethane-based mold can be preferably used. Specifically, in the presence of a reaction catalyst, phenols and aldehydes are added so that the ratio of aldehydes to 1 mol of phenols is generally 0.5 to 3.0 mol. -The benzyl ether type phenol resin, the resol type phenol resin, the novolak type phenol resin, their modified phenol resins, and their mixtures, which are obtained by the condensation reaction and are soluble in organic solvents, can be exemplified. One or more of them will be appropriately selected and used. Among these, in particular, the orthocresol-modified phenol resin modified with orthocresol, more preferably the benzyl ether type orthocresol-modified phenol resin and a mixture thereof, have solubility in an organic solvent and a polyisocyanate compound. Not only is it excellent in compatibility with the above, but also the strength (initial strength) of the obtained mold can be effectively improved, so that it is suitably used in the present invention.

The catalyst used in the above-mentioned addition / condensation reaction between the phenols and the aldehydes is not particularly limited, and a known acidic catalyst or basicity may be used depending on the desired type of phenol resin. In addition to the catalyst, various catalysts conventionally used for producing phenolic resins are appropriately used. Examples of such a catalyst include metal salts having metal elements such as tin, lead, zinc, cobalt, manganese, and nickel, and more specifically, lead naphthenate, zinc naphthenate, and the like. In addition to lead acetate, zinc chloride, zinc acetate, zinc borate, and lead oxide, combinations of acids and bases that can form such metal salts can be mentioned. Further, when such a metal salt is adopted as a reaction catalyst, the amount used is not particularly limited, but is generally about 0.01 to 5 parts by mass with respect to 100 parts by mass of phenols. It will be used at a certain rate.

Examples of the phenols that give the phenolic resin include phenol, orthocresol, metacresol, paracresol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol, and 2,6-dimethyl. Phenol, 3,4-dimethylphenol, 3,5-dimethylphenol, p-tert-butylphenol, o-tert-butylphenol, m-tert-butylphenol, nonylphenol and other alkylphenols, resorcinol, bisphenol F, bisphenol A and other polyvalents Phenol and mixtures thereof are mentioned, while aldehydes include, for example, formaldehyde, formarin, paraformaldehyde, polyoxymethylene, glioxal, furfural and mixtures thereof.

Further, as described above, the orthocresol-modified phenolic resin, which is one of the phenolic resins advantageously adopted in the present invention, includes, for example, orthocresol and phenol in the presence of a reaction catalyst such as a metal salt. In addition to (1) orthocresol-modified phenolic resin co-condensed with orthocresol and phenol, (2) orthocresol-modified phenolic resin mixed with orthocresol resin and phenolic resin, which can be obtained by reacting with other species. (3) Modified orthocresol-modified phenolic resin obtained by modifying the resins (1) and (2) with a modifier (modifier), and their (1), (2) and (3). ), A mixture or the like in which two or more of them are combined can be exemplified. The orthocresol-modified phenolic resins (1), (2) and (3) are all well known, and in the present invention, such known ones will be used as they are. .. As the ratio of phenol / orthocresol, a ratio of 1/9 to 9/1, preferably 3/7 to 7/3, and more preferably 4/6 to 6/4 is adopted on a mass basis. It will be.

Then, the polyol compound such as a phenol resin used as one of the main components of the organic binder for a mold according to the present invention as described above has a low viscosity, compatibility with a polyisocyanate solution described later, and a casting sand. From the viewpoint of coating properties, template physical properties, etc., a solution is generally dissolved in an organic solvent consisting of a combination of a polar organic solvent and a non-polar organic solvent, and the concentration thereof is about 30 to 80% by mass (hereinafter referred to as a solution). , "Polycarbonate solution").

On the other hand, in the organic binder for a template according to the present invention, the polyisocyanate compound used as one of the other main components thereof is subjected to a double addition reaction with the active hydrogen of a polyol compound such as a phenol resin as described above. It is a compound having two or more isocyanate groups in the molecule, which can chemically bond cast sands to each other by a urethane bond such as phenol urethane. Specific examples of such polyisocyanate compounds include aromatic, aliphatic, or alicyclic polyisocyanates such as diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate (hereinafter referred to as “polymeric MDI”), and hexamethylene diisocyanate. , 4,4'-Dicyclohexamethylene diisocyanate, as well as various conventionally known polyisocyanates such as prepolymers having two or more isocyanate groups obtained by reacting these compounds with a polyol can be mentioned. , Can be used alone, or may be used in combination of two or more.

Further, even in such a polyisocyanate compound, for the same reason as that of a polyol compound such as a phenol resin as described above, a non-polar organic solvent or a mixed solvent of a non-polar organic solvent and a polar solvent is generally used as a solvent. It will be used as a solution dissolved in this organic solvent so that the concentration is about 40 to 90% by mass. Depending on the type of polyisocyanate compound used, it is not always necessary to dissolve it in an organic solvent, and the undiluted solution can be used as it is. In the following, a stock solution of a polyisocyanate compound and a solution obtained by dissolving the polyisocyanate compound in an organic solvent are referred to as a polyisocyanate solution.

Here, as the organic solvent for dissolving the above-mentioned polyol compound or polyisocyanate compound, the organic solvent is non-reactive with the polyisocyanate compound and with respect to the solute (polyphenol compound or polyisocyanate compound) to be dissolved. The solvent is not particularly limited as long as it is a good solvent, but generally, the amount is such that i) a polar solvent for dissolving a polyol compound such as a phenol resin and ii) a polyol compound such as a phenol resin do not separate. It will be used in combination with a non-polar solvent for dissolving the polyisocyanate compound of.

More specifically, the polar solvent of i) described above includes, for example, an aliphatic carboxylic acid ester, and in particular, a dicarboxylic acid methyl ester mixture (manufactured by DuPont, USA; trade name: DBE; dimethyl glutarate and adipine). Dicarboxylic acid alkyl esters such as dimethyl acid and dimethyl succinate), methyl esters of vegetable oils such as rapeseed oil methyl esters, as well as ketones such as isophorone, ethers such as isopropyl ether, furfuryl alcohol and the like. Can be done. The non-polar solvent of ii) is, for example, petroleum-based hydrocarbons such as paraffins, naphthenes, and alkylbenzenes, and specific examples are Ipsol 150 (manufactured by Idemitsu Kosan Co., Ltd .; petroleum-based solvent). Examples thereof include Hysol 100 (manufactured by JXTG Energy Co., Ltd .; petroleum-based solvent), HAWS (manufactured by Shell Chemicals Japan Co., Ltd .; petroleum-based solvent) and the like.

In the present invention, in addition to the above-mentioned polyol compound and polyisocyanate compound, as components of the organic binder for the target template, a basic primary silane compound and hydrofluoric acid are further added. The reaction product with and the non-basic secondary silane compound were allowed to be contained. The presence of these specific reaction products and non-basic second silane compounds favorably improves the strength of the mold molded with the organic binder, especially the leaving strength of the mold after molding. At the same time, it is possible to effectively suppress or prevent the adverse effect of the external environment when the mold is stored and left, particularly the decrease in the strength of the mold in a high humidity atmosphere. That is, it is possible to efficiently improve or prevent the decrease in strength caused by the mold absorbing moisture in the air during storage and leaving, and to improve the moisture absorption resistance deterioration characteristics of the mold. It is. Moreover, in this way, the organic binder and the cast sand are kneaded by using the non-basic second silane compound in combination with the reaction product of the basic first silane compound and the hydrofluoric acid. In addition to being able to advantageously improve the pot life of the obtained cast sand composition, the fluidity of such a cast sand composition can be effectively improved, and the filling property is more excellent. Along with the formation of a mold, the surface of the obtained mold can be made smoother, and the surface texture can be improved advantageously.

The basic first silane compound that gives such a specific reaction product is an organic silicon compound having a structure in which an organic group having a basic group such as an amino group is bonded to silicon (Si). For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-. Aminopropyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl- Examples thereof include an alkoxysilane having an amino group such as 3-aminopropyltrimethoxysilane, hexamethyldisilazane, and a silane compound having a ureido group such as 3-ureidopropyltrialkoxysilane. Further, among these basic primary silane compounds, it is preferable to use basic alkoxysilane, and among them, alkoxysilane having an amino group is more preferable, and N-2- (aminoethyl) -3- is more preferable. Aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and 3-ureidopropyltrialkoxysilane will be used advantageously. The best reason for this alkoxysilane having an amino group is that it is easily available and that the alkoxy group is hydrolyzed to a hydroxyl group by the water content in the polyol compound or hydrofluoric acid. This is because the adhesion with the casting sand (aggregate or the like) becomes stronger and high mold strength can be exhibited.

Then, such a basic first silane compound is reacted with hydrofluoric acid, and the obtained reaction product is used in the present invention, but the reaction ratio is mass. By reference, a ratio of basic first silane compound / hydrofluoric acid = 2/8 to 8/2, preferably 3/7 to 7/3, more preferably 4/6 to 6/4 is adopted. Will be done. The concentration of hydrofluoric acid used here is preferably 10 to 65%, more preferably 20 to 60%, and even more preferably 40 to 55%.

By the way, in producing the specific reaction product used in the present invention as described above, for example, in a plastic container, a predetermined basic first silane compound and hydrofluoric acid are mixed and reacted. By squeezing, the desired reaction product can be easily obtained. At this time, in order to suppress the heat of reaction between the basic first silane compound and hydrofluoric acid, one of them is cooled and stirred while the other is continuously or intermittently. Therefore, it is desirable to prevent the rapid progress of the reaction by adding it. Further, in those reactions, in addition to the case where the reaction is allowed to proceed by adding hydrofluoric acid to the basic first silane compound, on the contrary, the basic first silane compound is hydrofluoric acid. It is also possible to add a monosilane compound. The temperature at the time of the reaction between the basic first silane compound and hydrofluoric acid is preferably suppressed to 80 ° C. or lower, more preferably 70 ° C. or lower, and further preferably 60 ° C. or lower. Be made to progress.

Here, adding the basic first silane compound or hydrofluoric acid little by little continuously or intermittently means that in the continuous addition method, a constant amount is added at a constant speed. The method of adding to the reaction system at a constant rate of addition is advantageously adopted, and in the intermittent addition method, it is possible to add at regular intervals at regular intervals. desirable. Further, in the intermittent addition method at such intervals, a fixed amount is added at a fixed time, for example, every 1 second, every 10 seconds, or every minute, or a reaction is carried out. It is also possible to adopt a method of gradually dropping into the system. By adding little by little in such a method, it is possible to advantageously prevent an increase in heat of reaction and effectively prevent deterioration of the physical properties of the obtained reaction product. Above all, if the method of dropping is adopted, it is possible to more effectively suppress the temperature rise due to the heat of reaction.

Then, in the present invention, it is desirable that a reaction product obtained by the reaction of such a basic first silane compound with hydrofluoric acid is formed in advance, and then such a reaction product is obtained. In this form, it is used together with a polyol compound or a polyislane compound to advantageously form a target organic binder. As described above, by forming the reaction product of the basic first silane compound and hydrofluoric acid in advance, the step of directly adding hydrofluoric acid becomes unnecessary, and thus the organic caking is performed. Safety can be advantageously ensured when preparing the agent and when using it to produce a cast sand composition. In addition, since the step of directly adding hydrofluoric acid is not required, the inside of the device is corroded even when a stainless steel or glass manufacturing device is used when manufacturing an organic binder or a cast sand composition. There is an advantage that it can be manufactured without any need. It goes without saying that the method for adding the specific reaction product is not limited to the examples, and such a reaction product exists as a constituent component thereof in the organic binder. If it is in the form to be obtained, in an appropriate addition form such as adding these basic primary silane compounds and hydrofluoric acid separately or together with the polyol compound and / or the polyisocyanate compound. It can be blended with a polyol compound or a polyisocyanate compound so that the desired reaction product is formed when used as an organic binder.

In the present invention, the amount of the reaction product of such a basic first silane compound and hydrofluoric acid used is 100 parts by mass of the polyol compound which is one of the constituents of the organic binder. On the other hand, a ratio of about 0.01 to 10.0 parts by mass, preferably about 0.1 to 2 parts by mass is preferably adopted. When the amount of such a reaction product used is less than 0.01 parts by mass, it becomes difficult to sufficiently exert the effect of using the reaction product, and when it is more than 10 parts by mass, it becomes difficult to sufficiently exert the effect. Problems such as difficulty in contributing to sufficient strength improvement of the obtained mold will occur.

On the other hand, the non-basic second silane compound used in combination with the reaction product as described above is an organic silicon compound in which a basic group such as an amino group is not bonded in its molecular structure, and is, for example, 3-. Glycydoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl Trimethoxysilane, 3-Isocyanoxide propyltriethoxysilane, chlorotrimethylsilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, Tris- (trimethoxysilylpropyl) isocyanurate, 3-acryloxylpropyltrimethoxy Examples thereof include silane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, p-styryltrimethoxysilane, and the like. I can. Among them, 3-glycidoxypropyltrimethoxysilane and 3-isocyanatepropyltriethoxysilane are preferably used advantageously. By using such a non-basic second silane compound in combination, the compatibility between the polyol compound side and the polyisocyanate compound side is improved, the fluidity as an organic binder is improved, and the casting sand (fire resistance) is improved. The wettability to the aggregate) is also improved, the fluidity of the cast sand composition is improved, and a mold having more excellent filling property can be advantageously molded in a form in which the surface texture thereof is improved. ..

In the present invention, the amount of the non-basic second silane compound used is about 0.01 to 10.0 parts by mass, preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the polyol compound. The ratio of about a part is preferably adopted. If the amount used is less than 0.01 parts by mass, problems such as difficulty in sufficiently fulfilling the expected functions due to the use of such a second silane compound are caused, and more than 10 parts by mass. In that case, problems such as high cost for producing the organic binder will occur.

Further, in the organic binder for a template according to the present invention, in addition to the above-mentioned polyol compound, polyisocyanate compound, specific reaction product, and non-basic second silane compound, an acid halide and halogenation are further added. At least one of the phosphoryl compound and the halide phosphine will be advantageously contained as one of the constituents. The strength of the mold molded using the cast sand composition obtained by kneading the organic binder and the foundry sand according to the present invention in the presence of such an acid halide, a halogenated phosphoryl compound, or a halide phosphin. And moisture absorption deterioration characteristics can be further improved, and in particular, the pot life of the casting sand composition obtained by kneading with casting sand while maintaining excellent mold strength and moisture absorption deterioration characteristics can be effectively achieved. It is possible to improve. The acid halide, the halogenated phosphoryl compound, or the halogenated phosphine is generally about 0.01 to 5 parts by mass, preferably about 0.1 to 2 parts by mass with respect to 100 parts by mass of the polyol compound. The ratio is preferably adopted.

Here, the acid halides described above are halides of aliphatic carboxylic acids and aromatic carboxylic acids, and are, for example, isophthalic acid chloride, benzoyl chloride, caprylic acid chloride, laurate chloride, myristic acid chloride, and palmitate chloride. , Isopalmitic acid chloride, stearate chloride, isostearic acid chloride, oleate chloride, sebacic acid dichloride, phenylacetyl chloride, 2-chlorobenzoyl chloride, 3-chlorobenzoyl chloride, 4-chlorobenzoyl chloride, 2-bromobenzoyl chloride, 3-bromobenzoyl chloride, 4-bromobenzoyl chloride, 2-iodobenzoyl chloride, 3-iodobenzoyl chloride, 4-iodobenzoyl chloride, butyric acid chloride, isobutyric acid chloride, valerate chloride, isovaleric acid chloride, caproic acid chloride, Enant acid chloride, pelargonic acid chloride, capric acid chloride, pentadecylate chloride, margaric acid chloride, linoleic acid chloride, linolenic acid chloride, phthalic acid chloride, terephthalic acid chloride, o-toluic acid chloride, m-toluic acid chloride, p- Examples thereof include toluyl acid chloride, anhydrous trimellitic acid chloride, trimethoxybenzoic acid chloride, brominated benzoyl, iodide benzoyl and the like, and among them, isophthalic acid chloride and lauric acid chloride are preferably used. The halogenated phosphoryl compound has the following formula: R _n −P (= O) X _(3-n) [However, R is an organic group, X is a halogen atom, and n is 0, 1 or 2. A compound having a halogen-substituted phosphoryl group (≡P = O) shown in [A], for example, phosphoryl chloride, phosphoryl bromide, phosphoryl iodide, phenylphosphonic acid dichloride, diphenylphosphinic acid chloride and the like. Further, the halogenated phosphin can be used in the following formula: R _n -PX _(3-n) [where R is an organic group, X is a halogen atom and n is 0, 1 or 2], for example, dichlorophenylphosphine, chlorodiphenylphosphine and the like can be used, and among them, phenylphosphonic acid dichloride is preferably used.

As described above, the urethane-curable organic binder for molds according to the present invention includes the basic primary silane compound and fluoride as described above, in addition to the polyol compound and the polyisocyanate compound that form a urethane bond such as phenol urethane. It contains a reaction product with hydrogen acid and a non-basic second silane compound as constituents, and more preferably contains at least one of an acid halide, a halogenated phosphoryl compound and a halogenated phosphin. However, for such organic binders, if necessary, a pot life extender (curing retarder: for example, higher fatty acid ester, etc.) different from the above-mentioned compounding components, and It is also possible to appropriately select and blend various known additives that have been conventionally used as organic binders for molds, such as a mold release agent, a strength deterioration inhibitor, and an antidrying agent. Of course, it goes without saying that these various additives are used in a quantitative range that does not impair the effects that can be enjoyed by the present invention. Among these various additives, the pot life extender (curing retarder) is used to suppress the urethanization reaction and prolong the pot life of the cast sand composition, and is also released. The mold agent reduces the resistance when the molded mold is removed from the mold, and a part of the cast sand composition blown and filled in the mold adheres to the mold when the mold is removed. It is used to prevent the generation of stains and to obtain a mold having a uniform molding surface and high accuracy.

Then, the urethane-curable organic binder for a mold according to the present invention having such a structure is kneaded with casting sand (refractory aggregate) in the same manner as in the conventional case to form a urethane-based gas-curable mold. A cast sand composition for the purpose of forming will be formed.

Specifically, for example, when molding a gas-curing mold by the cold box method, first, the cast sand (fire-resistant aggregate) is kneaded with the above-mentioned organic binder for a mold according to the present invention. A casting sand composition (kneaded sand) in which the surface of casting sand is coated with an organic binder for a mold is produced. That is, the reaction product of a polyol compound, a polyisocyanate compound, a basic first silane compound and hydrofluoric acid, and a non-basic second silane compound as organic binders for cast sand. And further, by sufficiently kneading and mixing various desired additives, the surface of the cast sand is coated with an organic binder for a mold to produce a cast sand composition.

At that time, the reaction product of the basic first silane compound and hydrofluoric acid, the non-basic second silane compound, and various other additives were uniformly applied to the cast sand composition. It is added to either or both of a solution of a polyol compound and a solution of a polyisocyanate compound prepared separately so that they can be mixed, and the mixture is mixed, or dissolved or dissolved in a suitable organic solvent. It is dispersed and mixed with a solution of a polyol compound or a solution of a polyisocyanate compound with a solution of a polyol compound at the time of kneading, or is formed as after the condensation is completed at the time of producing a polyol compound such as a phenol resin. It is also possible to add it directly to the polyol compound and mix it. Above all, in the present invention, it is desirable that such a specific reaction product be added to a solution of a separately prepared polyol compound, and a non-basic second silane compound is separately prepared. It is desirable to be able to add it to the solution of the polyisocyanate compound.

By the way, when producing such a cast sand composition, a solution of a polyol compound constituting an organic binder and a solution of a polyisocyanate compound are gradually subjected to a heavy addition reaction (urethaneization reaction) from the stage of mixing them. Will be prepared and prepared separately in advance, and will usually be mixed at the time of kneading with the cast sand. The kneading / mixing operation is preferably performed at a temperature in the range of −10 ° C. to 50 ° C. using a continuous or batch type mixer similar to the conventional one.

Further, the casting sand (refractory aggregate) to be kneaded with the organic binder for a mold according to the present invention is natural sand as long as it is a refractory sand conventionally used for a mold. However, even if it is artificial sand, there is no problem and it is not particularly limited. For example, Kay sand, Olivin sand, Zircon sand, Chromite sand, Alumina sand, Ferrochrome slag, Ferronickel slag, Rotor slag, Murite artificial particles (for example, the trade name "Tadachu Ceratech Co., Ltd." Cera beads ”), alumina-based artificial particles, various other artificial particles, and their regenerated sand and recovered sand can be mentioned, and one or more of these can be used in combination. Among these, silica sand, particularly aggregate having a high silica content such as fluttering sand, will be more preferably adopted. By using such an aggregate having a high silica content, the compatibility with silane in the binder component is improved, and the adhesiveness between the aggregate and the binder is increased, and when the mold is molded. It will lead to the improvement of the strength of.

Then, the cast sand composition obtained as described above is shaped in a molding die such as a die giving a desired shape, and then a catalyst gas for curing is aerated therein. As a result, the curing of the cast sand composition is promoted, and a gas curing mold is manufactured. Examples of the catalyst gas include conventionally known tertiary amine gases such as triethylamine, dimethylethylamine, and dimethylisopropylamine, as well as cyclic nitrogen compounds, pyridine, N-ethylmorpholine, and the like. At least one is appropriately selected and used in the usual quantitative range.

Further, when molding the target self-hardening mold by the room temperature self-hardening method, as in the case of the above-mentioned gas-curing mold, first, the casting sand surface is coated with an organic binder to form a casting sand composition. However, at that time, the cast sand composition used in the room temperature self-hardening method is further mixed with a curing catalyst together with the organic binder according to the present invention at the time of kneading. Become. Examples of the curing catalyst include bases, amines, metal ions and the like which are usually used in the known Ashland method.

Further, in the preparation of the cast sand composition for giving the gas-curing mold and the self-hardening mold described above, the blending ratio of the polyol solution and the polyisocyanate solution is such that the blending amounts of the polyol compound and the polyisocyanate compound, which are the active ingredients, respectively. A ratio of about 0.5 to 5.0 parts by mass, preferably about 1.0 to 3.0 parts by mass, respectively, with respect to 100 parts by mass of the foundry sand is preferably adopted. The blending ratio of the polyol compound and the polyisocyanate compound is not particularly limited, but generally, the polyol solution is such that the polyol compound: the polyisocyanate compound = 4: 6 to 6: 4 on a mass basis. And polyisocyanate solutions will be used in combination.

Thus, in the gas-cured mold and the self-hardening mold molded as described above, the filling density and strength thereof can be effectively improved, and further, the moisture absorption-resistant deterioration characteristic of the strength can be enhanced. It has become possible to use it advantageously for casting cast products made of various metals such as aluminum alloys, magnesium alloys, and iron.

Hereinafter, the present invention will be described in more detail by showing some typical examples of the present invention, but the present invention is subject to any restrictions due to the description of such examples. It goes without saying that it is not a thing. Further, in addition to the following examples, various changes and modifications to the present invention are made based on the knowledge of those skilled in the art, as long as they do not deviate from the gist of the present invention, in addition to the specific description described above. It should be understood that improvements can be made.

Further, regarding the organic binders prepared in the following Examples and Comparative Examples, (1) measurement of the strength of the mold molded from the cast sand composition obtained by using the organic binder, (2) the mold. Measurement of strength after moisture absorption deterioration, (3) evaluation of pot life of cast sand composition, (4) measurement of filling density, and (5) evaluation of casting surface are performed as follows. rice field.

(1) Measurement of mold strength After putting the kneaded cast sand composition into the sand magazine of the cold box molding machine, this cast sand composition is placed in a mold for producing a bending strength test piece, and the gauge pressure is: Fill at 0.3 MPa. Next, triethylamine gas was aerated in the mold at a gauge pressure of 0.2 MPa for 1 second with a gas generator, then air purge was performed at a gauge pressure of 0.2 MPa for 14 seconds, and then the mold was removed. A bending test piece (mold) having a width of 3 cm, a length of 8.5 cm, and a thickness of 1 cm is prepared. Then, the obtained test piece was left for 24 hours in a low humidity state of i) immediately after its molding and ii) temperature: 25 ° C. and relative humidity: 40%, and then a digital casting sand strength tester (Takachiho). The bending strength (kgf / cm ² ) is measured by Seiki Co., Ltd.).

(2) Measurement of mold strength after deterioration of moisture absorption In the same manner as in the case of the above-mentioned measurement of mold strength, a test piece is prepared from each cast sand composition, and then the obtained test piece (mold) is subjected to temperature. Bending strength (kgf / kgf / Measure cm ² ).

(3) Evaluation of pot life of the cast sand composition In the same manner as in the case of the above-mentioned measurement of the mold strength, when a test piece is prepared from each cast sand composition, the flattery sand as the cast sand and organic cohesion are formed. For each cast sand composition prepared by kneading with the agent, molding is performed immediately after kneading (waiting time after kneading: 0 minutes), and the obtained test piece and the molding are formed 120 minutes after kneading. After kneading (waiting time after kneading: 120 minutes), the strength of each of the obtained test pieces was measured as the mold strength, and the pot life was evaluated by comparing the values of the two mold strengths. conduct.

(4) Measurement of packing density After preparing a test piece (width: 3 cm × length: 8.5 cm × thickness: 1 cm) from each cast sand composition in the same manner as in the case of the above-mentioned measurement of mold strength, From the numerical value of the mass of the obtained test piece (mold), the packing density (g / cm ³ ) was calculated by the following formula. Two test pieces were prepared, and the average value of the numerical values of each mass was taken as the packing density (g / cm ³ ).
Filling density = test piece (mold) mass / test piece volume

(5) Evaluation of mold surface properties After preparing test pieces from each cast sand composition in the same manner as in the case of measuring the mold strength above, the surface properties (mold) of the obtained test pieces (mold) The feeling of touch) was evaluated. Specifically, five panelists evaluated the texture of the mold surface according to the following criteria, and evaluated the superiority or inferiority at the average level.
◎: Very smooth touch ○: Smooth touch △: Slightly rough touch ×: Very rough touch

-Preparation of phenol resin solution (1)-
In a three-necked reaction flask equipped with a refluxer, thermometer and stirrer, 100 parts by mass of phenol, 55.5 parts by mass of 92% by mass paraformaldehyde, and 0.2 of zinc naphthenate as a divalent metal salt. A part by mass was charged, the reaction was carried out at a reflux temperature for 90 minutes, and then the mixture was heated and concentrated to obtain a benzyl ether type phenol resin having a water content of 1% or less. Next, 50.0 parts by mass of the obtained phenol resin, 20.0 parts by mass of a polar organic solvent (DBE: manufactured by DuPont, USA) and a non-polar organic solvent (Hysol 100: manufactured by JXTG Energy Co., Ltd .; petroleum-based). A phenol resin solution (1) having a phenol resin content of 50.0% by mass was prepared by dissolving it using 30.0 parts by mass of the solvent).

-Preparation of phenol resin solution (2)-
In a three-port reaction flask equipped with a recirculator, thermometer and stirrer, 50 parts by mass of phenol, 50 parts by mass of orthocresol (phenol / orthocresol = 50/50), and 51 by 92% by mass of paraformaldehyde. .9 parts by mass and 0.15 parts by mass of zinc naphthenate as a divalent metal salt were charged, and after reacting at a reflux temperature for 90 minutes, they were concentrated by heating and modified with orthocresol having a water content of 1% or less. A benzyl ether type phenol resin was obtained. Next, 50.0 parts by mass of the obtained phenol resin, 20.0 parts by mass of a polar organic solvent (DBE: manufactured by DuPont, USA) and a non-polar solvent (Hysol 100: manufactured by JXTG Energy Co., Ltd .; petroleum solvent). ) Was dissolved using 30.0 parts by mass to prepare a phenol resin solution (2) having a phenol resin content of 50.0% by mass.

-Preparation of Polymeric MDI solution-
75.0 parts by mass of the polyisocyanate compound Polymeric MDI was dissolved with 25.0 parts by mass of a non-polar organic solvent (Ipsol 150: manufactured by Idemitsu Kosan Co., Ltd .; a petroleum solvent) to contain the polyisocyanate compound. A polypeptide MDI solution having an amount of 75.0% by mass was prepared.

-Production of reaction product of basic first silane compound and hydrofluoric acid-
N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane (KBM602: manufactured by Shin-Etsu Chemical Industry Co., Ltd.) was used as a basic primary silane compound while stirring at a temperature of 60 ° C. or lower. A reaction product (amine phosphate) is produced by subjecting 0.6 parts by mass of the first silane compound (KBM602) to a small amount of 0.6 parts by mass of 46% hydrofluoric acid to cause a reaction. did.

(Examples 1 to 6)
First, the reaction product of the first silane compound (KBM602) and hydrofluoric acid was added to 100 parts by mass of the phenol resin solution (1) prepared above at the ratio shown in Table 1 below. The polyol solution according to each of Examples 1 to 6 was prepared by adding, stirring and uniformly mixing. Further, various non-basic second silane compounds shown in Table 1 below are added to 100 parts by mass of the polypeptide MDI solution prepared above at the ratios shown in Table 1 below, and the mixture is stirred and uniformly. By mixing, each polyisocyanate solution according to each of Examples 1 to 6 was prepared.

Next, 1000 parts by mass of the flattery sand was put into the Dalton Co., Ltd. product river type tabletop mixer, and the polyol solution prepared as described above and the polyisocyanate solution prepared above were added to each of 10 parts. A cast sand composition was prepared by adding parts by mass, stirring for 60 seconds, and kneading. Then, using the obtained various cast sand compositions, each test piece (mold) was prepared, and according to the above measurement method, the mold strength immediately after molding and 24 hours after molding (kgf / cm ² ). , And the mold strength (kgf / cm ² ) after moisture absorption deterioration after 24 hours of molding was measured, and the obtained results are shown in Table 1 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 1 below.

(Example 7)
A cast sand composition was prepared in the same manner as in Example 1 except that the phenol resin solution (2) prepared above was used instead of the phenol resin solution (1). Then, a test piece (mold) was prepared using the obtained cast sand composition, and according to the above measurement method, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding, and the molding 24 The mold strength (kgf / cm ² ) after moisture absorption deterioration after time was measured, and the results are shown in Table 1 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 1 below.

(Example 8)
A cast sand composition was prepared in the same manner as in Example 1 except that 0.3 parts by mass of isophthalic acid chloride was further added at the time of preparing the polyisocyanate solution. Then, a test piece (mold) was prepared using the obtained cast sand composition, and according to the above measurement method, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding, and the molding 24 The mold strength (kgf / cm ² ) after moisture absorption deterioration after time was measured, and the results are shown in Table 1 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 1 below.

(Examples 9 to 10)
A cast sand composition was prepared in the same manner as in Example 1 except that 0.3 parts by mass of lauric acid chloride or phenylphosphonic acid dichloride was further added at the time of preparing the polyisocyanate solution. Then, after preparing a test piece (mold) using the obtained cast sand composition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding, and the molding 24 according to the above measurement method, and the molding 24 The mold strength (kgf / cm ² ) after moisture absorption deterioration after time was measured, and the results are shown in Table 1 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 1 below.

(Comparative Examples 1 to 5)
While the phenol resin solution (1) prepared above is prepared, various second silane compounds shown in Table 2 below are shown in Table 2 below with respect to 100 parts by mass of the polypeptide MDI solution prepared above. The polyisocyanate solution according to each of Comparative Examples 1 to 5 was prepared by adding in a ratio, stirring and uniformly mixing. Next, 1000 parts by mass of the flattery sand was put into the Dalton Co., Ltd. product river type tabletop mixer, and 10 parts by mass of each of the phenol resin solution (polycarbonate solution) and the polyisocyanate solution was put into the mixer, and the mixture was stirred for 60 seconds. , A cast sand composition was prepared by kneading. Then, a test piece (mold) was prepared using the obtained cast sand composition, and according to the above measurement method, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding, and the molding 24 The mold strength (kgf / cm ² ) after moisture absorption deterioration after time was measured, and the results are shown in Table 2 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 2 below.

(Comparative Example 6)
A cast sand composition was prepared in the same manner as in Comparative Example 1 except that the phenol resin solution (2) prepared above was used instead of the phenol resin solution (1). Then, a test piece (mold) was prepared using the obtained cast sand composition, and according to the above measurement method, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding, and the molding 24 The mold strength (kgf / cm ² ) after moisture absorption deterioration after time was measured, and the results are shown in Table 2 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 2 below.

(Comparative Example 7)
A cast sand composition was prepared in the same manner as in Comparative Example 1 except that N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane (KBM602) was further prepared when preparing the polyisocyanate solution. Then, a test piece (mold) was prepared using the obtained cast sand composition, and according to the above measurement method, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding, and the molding 24 The mold strength (kgf / cm ² ) after moisture absorption deterioration after time was measured, and the results are shown in Table 2 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 2 below.

(Comparative Example 8)
While preparing the phenolic resin solution (1) prepared above, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane (KBM602) is prepared with respect to 100 parts by mass of the polypeptide MDI solution prepared above. ) Was added at the ratios shown in Table 2 below, stirred, and uniformly mixed to prepare a polyisocyanate solution. Next, 1000 parts by mass of the flattery sand was put into the Dalton Co., Ltd. product river type tabletop mixer, and 10 parts by mass of each of the phenol resin solution (polycarbonate solution) and the polyisocyanate solution was put into the mixer, and the mixture was stirred for 60 seconds. , A cast sand composition was prepared by kneading. Then, a test piece (mold) was prepared using the obtained cast sand composition, and according to the above measurement method, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding, and the molding 24 The mold strength (kgf / cm ² ) after moisture absorption deterioration after time was measured, and the results are shown in Table 2 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 2 below.

(Comparative Example 9)
To 100 parts by mass of the phenolic resin solution (1) prepared above, the reaction product of the first silane compound (KBM602) and hydrofluoric acid was added at the ratio shown in Table 2 below. A polyol solution was prepared by stirring and mixing uniformly, while a polyisocyanate solution containing no non-basic secondary silane compound or the like was prepared. Next, 1000 parts by mass of the flattery sand was put into the Dalton Co., Ltd. product river type tabletop mixer, and 10 parts by mass of each of the polyol solution and the polyisocyanate solution were put into the mixer, and the mixture was stirred for 60 seconds and kneaded. , A cast sand composition was prepared. Then, a test piece (mold) was prepared using the obtained cast sand composition, and according to the above measurement method, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding, and the molding 24 The mold strength (kgf / cm ² ) after moisture absorption deterioration after time was measured, and the results are shown in Table 2 below. In addition, the mold strength (kgf / cm ² ) immediately after molding and 24 hours after molding were measured using the cast sand composition after waiting for 120 minutes from kneading, and the pot life was evaluated. Furthermore, the measurement of the packing density and the evaluation of the surface texture of the mold were also performed. The results are shown in Table 2 below.

As is clear from the comparison of the results in Tables 1 and 2, the reaction product and non-basic of the basic primary silane compound and hydrofluoric acid, together with the predetermined phenolic resin and polyisocyanate, according to the present invention. A cast sand composition was prepared using the organic binders obtained in Examples 1 to 7 further containing the second silane compound of No. 1 as a constituent component, and further molded from the mold. The (test piece) has excellent properties not only in the mold strength under normal humidity environment but also in the mold strength after moisture absorption deterioration under high humidity, and the packing density of the mold. It is recognized that the surface texture of the mold is smooth. It is also clear from the results in Table 1 that such actions and effects can be further improved by the organic binders according to Examples 8 to 10.

On the other hand, a template obtained by using the organic binder (containing only a non-basic second silane compound) in Comparative Examples 1 to 8 to which no such reaction product (amine phosphate) was added ( In the test piece), the mold strength under normal humidity environment is not sufficient, the filling density is low, the surface texture of the mold is poor, and the mold strength after moisture absorption deterioration is the strength. It is recognized that the molds obtained by using such an organic binder are not practical because the deterioration is remarkable and the moisture absorption deterioration resistance is inferior. Further, in the organic binder according to Comparative Example 9 in which only amine phosphate (reaction product) is contained, the filling density of the mold is not sufficient, and the surface texture of the mold is also such. It is recognized that it lacks smoothness.

Claims (13)

A urethane-curable organic binder used for molding urethane-based molds, which is a reaction product of a basic first silane compound and hydrofluoric acid together with a polyol compound and a polyisocyanate compound, and a non-basic one. The second silane compound is further contained as a constituent component, and the second silane compound is selected from the group consisting of epoxysilane, isocyanatesilane, chlorosilane, mercaptosilane, isocyanuratesilane, acrylicsilane and methacrylsilane. A urethane curable organic binder for molds, which is characterized by. The urethane-curable organic binder for a mold according to claim 1, wherein a reaction product of the first silane compound and hydrofluoric acid is formed in advance and contained in the form of the reaction product. Agent. The urethane-curable organic binder for a mold according to claim 1 or 2, wherein the polyol compound is a phenol resin. The urethane-curable organic binder for a mold according to claim 3, wherein the phenol resin is an orthocresol-modified phenol resin. The template according to any one of claims 1 to 4, wherein the reaction product is used in a ratio of 0.01 to 10 parts by mass with respect to 100 parts by mass of the polyol compound. Urethane curable organic binder for. The second silane compound according to any one of claims 1 to 5, wherein the second silane compound is used in a ratio of 0.01 to 10 parts by mass with respect to 100 parts by mass of the polyol compound. Urethane curable organic binder for molds. The urethane-curable organic binder for a mold according to any one of claims 1 to 6, wherein the first silane compound is an alkoxysilane containing an amino group. The alkoxysilane containing an amino group is 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl). ) -3-Aminopropyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2 The urethane-curable organic binder for a mold according to claim 7, which is selected from the group consisting of -aminoethyl-3-aminopropyltrimethoxysilane and 3-ureidopropyltrialkoxysilane. The reaction product of the basic first silane compound and hydrofluoric acid is contained in the polyol compound, while the non-basic second silane compound is contained in the polyisocyanate compound. The urethane curable organic binder for a mold according to any one of claims 1 to 8 , which is characteristic. The urethane-curable mold for a mold according to any one of claims 1 to 9 , further comprising at least one of an acid halide, a halogenated phosphoryl compound, and a halogenated phosphin as a constituent component. Organic binder. The process of preparing a polyol solution in which a polyol compound is dissolved in an organic solvent, and
The process of preparing a polyisocyanate solution in which a polyisocyanate compound is dissolved in an organic solvent, and
A step of allowing a reaction product of a basic first silane compound and hydrofluoric acid to be present in the polyol solution and / or the polyisocyanate solution.
In the polyol solution and / or the polyisocyanate solution, a non-basic second silane compound selected from the group consisting of epoxysilane, isocyanatesilane, chlorosilane, mercaptosilane, isocyanuratesilane, acrylicsilane and methacrylsilane is added. The process of containing and
The step of mixing the polyol solution obtained through each of the above steps with the polyisocyanate solution is performed.
A method for preparing a urethane-curable organic binder for a mold, which comprises. A casting sand composition comprising the urethane curable organic binder for a mold according to any one of claims 1 to 10 and casting sand. A mold according to claim 12 , wherein the cast sand composition is formed and cured.