Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
  • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
  • B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
  • B22C1/22—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/54—Polycondensates of aldehydes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/83—Chemically modified polymers

Definitions

• the present invention relates to a mold organic binder used for molding a urethane-based gas-curing mold or self-hardening mold used in sand mold casting, a casting sand composition obtained by using the same, and such casting sand.
• the present invention relates to a mold obtained by molding a composition.
• a polyol compound such as a phenol resin and a polyisocyanate compound such as diphenylmethane diisocyanate are used as a binder, and their polyaddition reaction (urethanization).
• urethane molds made by utilizing the reaction), for example, phenolic urethane molds.
• urethane-type molds such as phenol-urethane-type molds, there is no need for heating during molding, mass-produced gas-cured molds produced by the amine cold box method using amine gas as a catalyst, Non-mass production type self-hardening molds manufactured by the method are widely known.
• the gas-curing mold by the amine cold box method is usually a granular refractory foundry sand, a mixer, and an organic viscosity for a mold comprising a phenol resin solution using an organic solvent as a solvent and a polyisocyanate compound solution.
• the foundry sand composition After producing a foundry sand composition obtained by coating the surface of such foundry sand with an organic binder by kneading with a binder, the foundry sand composition is blown into a predetermined mold to form a mold. And is cured by passing an amine-based catalyst gas through it.
• a self-hardening mold by the room temperature self-hardening method is used when a granular refractory casting sand is kneaded with an organic binder for a mold comprising a phenol resin solution and a polyisocyanate compound solution using an organic solvent as a solvent. And the resulting mixture is immediately formed into a desired shape.
• urethane-based mold such as a phenol-urethane-based mold obtained by utilizing such a polyaddition reaction (urethanization reaction) between a phenol resin and a polyisocyanate compound
• the chemical bonding characteristics cause air
• moisture absorption deterioration such as hardening inhibition and strength deterioration due to moisture in the inside.
• JP-A-1-501630 Patent Document 1
• silane compounds such as epoxy silane, amino silane, and ureido silane are added as a countermeasure for preventing moisture absorption deterioration of the mold produced by the cold box method.
• silane compound even with such a silane compound, sufficient characteristics have not yet been secured, and further establishment of measures for preventing moisture absorption deterioration has been desired.
• Patent Document 2 a urethane for a mold is obtained by further combining a polyol compound and a polyisocyanate compound with a silane compound having an isocyanate group or an acrylic compound having an isocyanate group. It has been clarified that by configuring a curable organic binder, it is possible to prevent moisture absorption deterioration of the mold and maintain excellent mold strength, but there is prepared a special isocyanate group-containing compound. There was a need to do.
• Patent Document 3 discloses a binder composition for producing a gaseous tertiary amine curable mold comprising a phenol resin and an isocyanate compound combined with boric acid. Further, it has been clarified that a silane compound can be contained in order to improve the adhesion between the binder component and the aggregate. And by using the binder composition containing such boric acid, the pot life is longer than that of the conventional mold manufacturing composition, and therefore, the binder and the granular refractory aggregate It is said that the strength as a mold can be maintained even if it is kneaded and left for several hours, but the evaluation of the mold strength there is performed under dry conditions where the humidity is not high. However, under high humidity conditions, the mold strength was significantly lowered due to moisture absorption deterioration, and it was difficult to maintain sufficient strength.
• the present invention has been made in the background of such circumstances, and the problem to be solved is a urethane-curable organic material that can advantageously provide a mold having improved moisture absorption resistance characteristics. It is also intended to provide a binder, and also to provide a urethane-curable organic binder for molds that can effectively improve the mold strength by leaving after molding, and such An object of the present invention is to provide a foundry sand composition capable of imparting excellent mold characteristics using a urethane curable organic binder, and a mold having excellent characteristics formed using the foundry sand composition.
• the present invention can be suitably implemented in various aspects as listed below.
• each aspect described below can be employed in any combination, and aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification. It should be understood that the invention can be recognized based on the grasped inventive idea.
• a urethane-curing organic binder used for molding urethane-based molds comprising a reaction product of a basic silane compound and an acid or a halide thereof together with a polyol compound and a polyisocyanate compound.
• a urethane curable organic binder for molds further comprising: (2) It is composed of two liquids, liquid A containing the polyol compound and liquid B containing the polyisocyanate compound, and the liquid A reacts with the basic silane compound and an acid or a halide thereof.
• the reaction product is Used in a proportion of 0.1 to 2.0 parts by mass, 1) The urethane-cured organic binder for molds according to any one of the embodiments (6). (8) The urethane curable organic viscosity for a mold according to any one of the above aspects (1) to (7), wherein the basic silane compound is an alkoxysilane containing an amino group. Binder.
• the above-mentioned 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-aminoethyl-3-aminopropyltrimethoxysilane and 3-ureidopropyltrialkoxysilane selected from the group consisting of urethane for molds according to the aspect (8), curable organic Binder.
• the acid or halide thereof is hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, boric acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, formic acid, acetic acid.
• a foundry sand composition comprising the urethane curable organic binder for molds according to any one of the aforementioned aspects (1) to (11) and foundry sand.
• a basic silane compound and an acid or a halide thereof are further added.
• a basic silane compound and an acid or a halide thereof are further added.
• the foundry sand composition obtained by kneading the organic binder for molds according to the present invention into foundry sand it is possible to provide a mold having the above-mentioned excellent characteristics, and such a cast product.
• the mold molded using the sand composition it has excellent mold strength and can be advantageously used in the casting process of the target metal as a mold having improved strength and moisture absorption resistance. It becomes.
• a higher fatty acid ester together with the reaction product of the basic silane compound and the acid or the halide thereof as described above.
• Strength and its hygroscopic deterioration characteristics can be further improved, and more effective extension of the pot life of the foundry sand composition obtained by kneading with foundry sand is maintained while maintaining such characteristics. The characteristic of obtaining can be demonstrated.
• the polyol compound used as one of the main components is not particularly limited.
• Various known polyol compounds used for 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, a copolymer of ethylene oxide and propylene oxide, tetrahydrofuran and Examples thereof include a copolymer of ethylene oxide, a copolymer of tetrahydrofuran and propylene oxide, and a copolymer of tetrahydrofuran and 3-methyltetrahydrofuran.
• the polyol compound used when molding a urethane mold various known phenol resins used when molding a phenol urethane mold can be suitably used. Specifically, in the presence of a reaction catalyst, phenols and aldehydes are added so that the aldehydes are generally in a ratio of 0.5 to 3.0 moles per mole of the phenols. Examples of the benzyl ether type phenol resin, resol type phenol resin, novolak type phenol resin, and their modified phenol resins, which are soluble in organic solvents, obtained by condensation reaction, and mixtures thereof can be exemplified. One or two or more of them are appropriately selected and used.
• ortho-cresol-modified phenol resins modified with ortho-cresol more preferably benzyl ether-type ortho-cresol-modified phenol resins and mixtures thereof include solubility in organic solvents and polyisocyanate compounds.
• the strength (initial strength) of the obtained mold can be effectively improved, and therefore it is preferably used in the present invention.
• the catalyst used in the addition / condensation reaction between the phenols and aldehydes is not particularly limited, and may be a known acidic catalyst or basic acid depending on the type of phenol resin desired.
• various catalysts conventionally used for producing phenolic resins are appropriately used.
• catalysts include metal salts having metal elements such as tin, lead, zinc, cobalt, manganese, and nickel. More specifically, lead naphthenate, zinc naphthenate, In addition to lead acetate, zinc chloride, zinc acetate, zinc borate, lead oxide, a combination of an acid and a base capable of forming such a metal salt can be exemplified.
• 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. Will be used at a rate of
• phenols that give phenol resins include alkylphenols such as phenol, cresol, xylenol, p-tert-butylphenol, and nonylphenol, polyhydric phenols such as resorcinol, bisphenol F, and bisphenol A, and mixtures thereof.
• aldehydes include formaldehyde, formalin, paraformaldehyde, polyoxymethylene, glyoxal, furfural, and mixtures thereof.
• orthocresol-modified phenol resin that is one of the phenol resins advantageously employed in the present invention includes, for example, orthocresol and phenol in the presence of a reaction catalyst such as a metal salt.
• a reaction catalyst such as a metal salt.
• Ortho-cresol-modified phenol resin of co-condensation of ortho-cresol and phenol (2) Mixed ortho-cresol-modified phenol resin of ortho-cresol resin and phenol resin
• Modified orthocresol-modified phenolic resins obtained by modifying the resins of (1) and (2) with a modifying agent (modifier), and (1), (2) and (3) ) And a mixture of two or more of them can be exemplified.
• the ortho-cresol-modified phenol resins (1), (2) and (3) are well known, and such known ones are used as they are in the present invention. .
• the ratio of phenol / orthocresol is 1/9 to 9/1, preferably 3/7 to 7/3, more preferably 4/6 to 6/4, based on mass. It will be.
• a 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 compound solution described later, and casting sand.
• a solution in which the concentration is about 30 to 80% by mass, which is dissolved in an organic solvent formed by combining a polar organic solvent and a nonpolar organic solvent
• it is used in the state of “polyol compound solution”.
• the polyisocyanate compound used as the other main component is subjected to a polyaddition reaction with active hydrogen of a polyol compound such as a phenol resin as described above. It is a compound having in the molecule two or more isocyanate groups capable of chemically bonding foundry sands with urethane bonds such as phenol urethane.
• polyisocyanate compounds include aromatic, aliphatic or alicyclic polyisocyanates such as diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate (hereinafter referred to as “polymeric MDI”), hexamethylene diisocyanate,
• polymeric MDI polymethylene polyphenylene polyisocyanate
• hexamethylene diisocyanate hexamethylene diisocyanate
• various conventionally known polyisocyanates such as prepolymers having two or more isocyanate groups obtained by reacting these compounds with polyols can be mentioned. You may use, or may use it in combination of 2 or more types.
• a nonpolar organic solvent or a mixed solvent of a nonpolar organic solvent and a polar solvent is used as a solvent. It is used as a solution dissolved in this organic solvent so that the concentration is about 40 to 90% by mass.
• a polyisocyanate compound stock solution and a solution obtained by dissolving a polyisocyanate compound in an organic solvent are referred to as a polyisocyanate compound solution.
• the organic solvent for dissolving the above-described polyol compound and polyisocyanate compound is non-reactive with the polyisocyanate compound and is a solute (polyol compound or polyisocyanate compound) to be dissolved.
• a solute polyol compound or polyisocyanate compound
• it is not particularly limited as long as it is a good solvent in general, i) an amount that does not cause separation of i) a polar solvent for dissolving a polyol compound such as a phenol resin, and ii) a polyol compound such as a phenol resin.
• a non-polar solvent for dissolving the polyisocyanate compound In combination with a non-polar solvent for dissolving the polyisocyanate compound.
• examples of the polar solvent of i) described above include, for example, aliphatic carboxylic acid esters, in particular, 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
• vegetable oils such as rapeseed oil methyl ester
• ketones such as isophorone
• ethers such as isopropyl ether
• furfuryl alcohol furfuryl alcohol
• non-polar solvent of the above ii) for example, petroleum hydrocarbons such as paraffins, naphthenes, and alkylbenzenes
• specific examples include Ipsol 150 (manufactured by Idemitsu Kosan Co., Ltd .; petroleum solvent), Hysol 100 (manufactured by JX Energy Co., Ltd .; petroleum solvent), HAWS (manufactured by Shell Chemicals Japan Co., Ltd .; petroleum solvent) and the like can be exemplified.
• the basic silane compound that gives such a specific reaction product is an organosilicon compound having a structure in which an organic group having a basic group such as an amino group is bonded to silicon (Si).
• Si silicon
• basic alkoxysilanes are preferably used, and among them, alkoxysilanes having an amino group are more preferable, and N-2- (aminoethyl) -3-aminopropylmethyldimethoxy is more preferable.
• Silane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-ureidopropyltrialkoxysilane will be advantageously used.
• the reason why the alkoxysilane having an amino group is the best is that the alkoxy group is hydrolyzed by the water in the polyol compound, acid or halide thereof in addition to being easily available, and changes to a hydroxyl group. This is because adhesion to foundry sand (such as aggregate) becomes stronger and high mold strength can be exhibited.
• Examples of the acid or halide thereof that can be reacted with such a basic silane compound include inorganic acids, organic acids, and halides thereof such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid.
• Inorganic acids such as hydrofluoric acid and boric acid, organic sulfonic acids such as benzenesulfonic acid, paratoluenesulfonic acid and trifluoromethanesulfonic acid; organic carboxylic acids such as formic acid, acetic acid and benzoic acid; organic phosphonic acids and the like Among them, hydrochloric acid, hydrobromic acid, phosphoric acid, hydrofluoric acid, benzenesulfonic acid, paratoluenesulfonic acid, trifluoromethanesulfonic acid and the like are advantageously used, and particularly hydrofluoric acid. Recommended to use.
• halide examples include halides of organic acids such as the above organic sulfonic acids, organic carboxylic acids, and organic phosphonic acids.
• organic acids such as the above organic sulfonic acids, organic carboxylic acids, and organic phosphonic acids.
• phenylphosphonic acid dichloride isophthalic acid chloride, benzoyl chloride, caprylic acid chloride, lauric acid.
• phenylphosphonic acid dichloride isophthalic acid chloride, benzoyl chloride, caprylic acid chloride, lauric acid.
• any combination can be adopted as long as it can form a reaction product thereof.
• -2- (Aminoethyl) -3-aminopropylmethyldimethoxysilane and hydrochloric acid N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane and hydrofluoric acid, N-2- (aminoethyl) -3 -Combinations of aminopropylmethyldimethoxysilane and phenylphosphonic acid dichloride can be mentioned.
• the ratio of basic silane compound / acid or halide thereof used to obtain the desired reaction product is 2/8 to 8/2, preferably 3/7 to 7/3 on a mass basis. More preferably, a ratio of 4/6 to 6/4 is adopted.
• the use amount of the reaction product of the basic silane compound and the acid or its halide is 0.1 to 100 parts by mass of 100 parts by mass of the polyol compound which is one of the components of the organic binder.
• a ratio of about 2.0 parts by mass, preferably about 0.2 to 1.0 parts by mass is suitably employed.
• the amount of such reaction product used is less than 0.1 parts by mass, the effect of the use of such a reaction product is not sufficiently exhibited, and more than 2.0 parts by mass. As a result, problems such as difficulty in contributing to sufficient improvement in the strength of the obtained mold arise.
• a predetermined basic silane compound and a predetermined acid or a halide thereof are mixed and reacted in a plastic container.
• the target reaction product can be easily obtained.
• one of them is cooled or stirred while the other is continuously or intermittently. It is desirable to prevent the rapid progress of the reaction by adding them.
• the basic silane compound is added to the acid or the halide thereof.
• the temperature during the reaction between the basic silane compound and the acid or its halide is preferably 80 ° C. or less, more preferably 70 ° C. or less, and even more preferably 60 ° C. or less. It is done.
• adding a basic silane compound or an acid or a halide thereof little by little continuously or intermittently means that a constant amount is added at a constant speed in the continuous addition method.
• a method of adding to the reaction system at a constant rate of addition is advantageously employed, and in the intermittent addition method, it is possible to add at regular intervals and at regular intervals. desirable.
• a predetermined amount of time is added or a reaction is made. It is also possible to adopt a method of gradually dropping into the system.
• the form of such a reaction product is used.
• it is used together with a polyol compound or a polyisocyanate compound to advantageously constitute a target organic binder.
• a reaction product of a basic silane compound and an acid or a halide thereof is formed in advance, so that a step of adding an acidic substance such as an acid is not required, and therefore a strong acid is used.
• the safety in producing the foundry sand composition can be advantageously ensured.
• the method of adding such a specific reaction product is not limited to those exemplified, and such a reaction product exists as a component in the organic binder.
• these basic silane compounds, acids or halides thereof can be blended with polyol compounds or polyisocyanate compounds in an appropriate form.
• a higher fatty acid ester is advantageously contained as one of the constituent components. It will be. Due to the presence of this higher fatty acid ester, the strength and moisture absorption deterioration characteristics of a mold molded using such an organic binder can be further improved, and in particular, excellent mold strength and moisture absorption deterioration characteristics are maintained. As it is, it is possible to effectively improve the pot life of the foundry sand composition obtained by kneading with the foundry sand.
• the higher fatty acid of the higher fatty acid ester refers to a fatty acid having a large number of carbon atoms in the molecule and generally having 12 or more carbon atoms, Usually, fatty acids having 12 to 30 carbon atoms, preferably 14 to 25, more preferably 16 to 20 carbon atoms are suitably used.
• the higher fatty acid ester is generally in a proportion of generally 0.1 to 40 parts by weight, preferably 0.5 to 30 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the polyol compound.
• fatty acid esters examples include saturated fatty acid esters such as lauric acid esters, palmitic acid esters, stearic acid esters, isostearic acid esters, hydroxystearic acid esters, and myristic acid esters, oleic acid esters, and linoleic acid.
• saturated fatty acid esters such as lauric acid esters, palmitic acid esters, stearic acid esters, isostearic acid esters, hydroxystearic acid esters, and myristic acid esters, oleic acid esters, and linoleic acid.
• unsaturated fatty acid esters such as esters, linolenic acid esters, and ricinoleic acid esters.
• an unsaturated fatty acid ester more preferably a ricinoleic acid ester, more preferably a polycondensate of ricinoleic acid and ethylene glycol or glycerin, and a self-condensate of ricinoleic acid. More preferably it is.
• the urethane curable organic binder for molds comprises a basic silane compound and an acid or a halide thereof as described above in addition to a polyol compound and a polyisocyanate compound that form a urethane bond such as phenol urethane.
• the reaction product is included as a constituent component, and more preferably a higher fatty acid ester is included.
• Such an organic binder may also contain the above-described compounding as necessary.
• Various known additives conventionally used in organic binders for molds such as pot life extenders (curing retarders) different from the ingredients, mold release agents, strength deterioration inhibitors, and drying inhibitors Can be appropriately selected and blended.
• the pot life extender (curing retarder) is used to suppress the urethanization reaction and extend the pot life of the casting sand composition.
• the mold agent reduces resistance when the molded mold is removed from the mold, and part of the foundry sand composition blown and filled in the mold adheres to the mold when the mold is removed. This is used to prevent the occurrence of spotting and to obtain a mold with a uniform molding surface and high accuracy.
• the urethane curable organic binder for molds according to the present invention thus obtained is kneaded into foundry sand (refractory aggregate) in the same manner as in the prior art to form a urethane-based gas curable mold. Therefore, the foundry sand composition is to be formed.
• the above-described organic binder for mold according to the present invention is kneaded with foundry sand (fireproof aggregate).
• a casting sand composition (kneaded sand) is produced by coating the casting sand surface with an organic binder for molds. That is, for the foundry sand, as an organic binder, a polyol compound, a polyisocyanate compound, a reaction product of a basic silane compound and an acid or a halide thereof, and further various desired additives are sufficiently provided.
• the molding sand composition is produced by coating the molding sand surface with the organic binder for casting.
• the reaction product of the basic silane compound and the acid or its halide and other various additives are separately prepared so that the compound can be uniformly mixed with the foundry sand composition. It is added to or mixed with one or both of the solution and the polyisocyanate compound solution, or dissolved or dispersed in an appropriate organic solvent, and this is mixed with a polyol compound solution or It can be mixed with the polyisocyanate compound solution into the foundry sand, or it can be added directly to the formed polyol compound and mixed, such as after completion of the condensation during the production of the polyol compound such as phenol resin. Is possible.
• the organic binder for a mold according to the present invention is composed of two liquids, a liquid A containing a polyol compound (polyol compound solution) and a liquid B containing a polyisocyanate compound (polyisocyanate compound solution).
• the solution A is made to contain the specific reaction product.
• reaction product when such a specific reaction product is contained (added) in the B liquid mainly composed of a polyisocyanate compound, the reaction product reacts with the polyisocyanate compound, and the various effects described above are obtained. There is a risk that you will not be able to enjoy it.
• liquid of this specific reaction product is liquid A
• a solution containing a polyol compound as a main component a basic silane compound, an acid, or a halide thereof may be added to the liquid A in an appropriate form as long as it can be present as a constituent component. Is possible.
• the specific reaction product formed in advance is added to the liquid A, the water content is 0.2 to 99.5% by mass, preferably 0.5 to 50% by mass, more preferably 1 to 25% by mass. % Of the reaction product is appropriately prepared and added to the liquid A (solution containing a polyol compound as a main component).
• the water content in the liquid A is 0.1 to 15% by mass. It is important to adjust.
• the water content in the liquid A constituting the organic binder is 0.1 to 15% by mass, preferably 0.15 to 10% by mass, and more preferably 0.2 to 6% by mass.
• the polyol compound solution and the polyisocyanate compound solution constituting the organic binder are gradually polyaddition reaction (urethanization reaction) from the stage of mixing them. Therefore, it is prepared separately and prepared in advance, and usually mixed at the time of kneading with foundry 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 mixer similar to the conventional one.
• the foundry sand (fire-resistant aggregate) kneaded with the organic binder for molds according to the present invention is natural sand as long as it is a fire-resistant one conventionally used for molds.
• artificial sand is not particularly limited.
• natural silica sand (including reclaimed sand) having a high silica content is more suitably employed.
• the casting sand composition obtained as described above is shaped in a mold such as a mold having a molding cavity that gives a desired shape, and then a catalyst gas for curing is formed. By aeration, the curing of the foundry sand composition is promoted and a gas curing mold is produced.
• the catalyst gas include conventionally known tertiary amine gases such as triethylamine, dimethylethylamine, dimethylisopropylamine, and cyclic nitrogen compounds such as pyridine and N-ethylmorpholine. At least one of these is appropriately selected and used in a normal quantitative range.
• a casting sand composition in which the surface of the casting sand is coated with an organic binder is further mixed with a curing catalyst together with the organic binder according to the present invention at the time of kneading.
• the curing catalyst include bases, amines, metal ions and the like that are usually used in the known Ashland method.
• the blending amounts of the polyol compound solution and the polyisocyanate compound solution are the blending amounts of the polyol compound and the polyisocyanate compound, which are 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, with respect to 100 parts by mass of the foundry sand is suitably employed.
• a solution or a polyisocyanate compound solution is used in combination.
• the strength can be effectively improved, and further, the moisture absorption deterioration resistance characteristic of the strength can be enhanced. Therefore, it can be advantageously used for casting casting products made of various metals such as magnesium alloy and iron.
• the obtained test piece was left standing for 24 hours under the conditions of i) immediately after the molding and ii) normal temperature and humidity of air temperature: 25 ° C. and relative humidity: 50%.
• the bending strength (kgf / cm 2 ) of each is measured by Takachiho Seiki Co., Ltd.).
• test piece (mold) is : 10 ° C, relative humidity: 90% in a sealed container for 120 minutes or 24 hours, and then bending strength (kgf / cm 2 ) using a digital foundry sand strength tester (manufactured by Takachiho Seiki Co., Ltd.) ).
• phenol resin solution having a phenol resin content of about 51% by mass was prepared.
• a polar organic solvent DBE: manufactured by DuPont, USA
• a nonpolar organic solvent Ipsol 150: manufactured by Idemitsu Kosan Co., Ltd.
• polyisocyanate compound solution (1) While dissolving 146 mass parts of polymeric MDI which is a polyisocyanate compound using 38.24 mass parts of a nonpolar organic solvent (Ipsol 150: made by Idemitsu Kosan Co., Ltd.), 0.93 of polymeric MDI amount was added there.
• a polyisocyanate compound solution containing about 79% by mass of a polyisocyanate compound was prepared by adding mass% of isophthalic acid chloride.
• a reaction retarder isophthalic acid chloride
• Examples 1 to 20 First, the reaction product prepared by previously reacting 197 parts by mass of the phenol resin solution prepared in the preparation (1) of the phenol resin solution with a predetermined basic silane compound and an acid or a halide thereof. Products A to T were added in the proportions shown in Tables 3 and 4 below, and stirred to mix uniformly. Next, the Enshu reclaimed sand is put into Dalton Co., Ltd.
• Example 21 foundry sand was obtained in the same manner as in Example 18 except that the solution of the ortho-cresol-modified phenol resin prepared in the preparation (2) of the phenol resin solution was used as the polyol compound. A composition was prepared, and a test piece (mold) formed from the obtained foundry sand composition was subjected to the above-described measurement method, and the mold strength (kgf / cm 2 ) immediately after molding and 24 hours after molding. The mold strength (kgf / cm 2 ) after moisture absorption deterioration for 120 minutes after molding was measured, and the obtained results are shown in Table 4 below.
• a reaction product of a basic silane compound and an acid or a halide thereof is further added as a constituent component together with a predetermined phenol resin and polyisocyanate.
• a conventional molding sand composition is used in the mold (test piece) obtained by preparing a molding sand composition using the organic binder obtained in Examples 1 to 21 to be contained, and then molding the composition. It is recognized that the mold has excellent properties not only in the mold strength under the humidity environment but also in the mold strength after the moisture absorption deterioration under the high humidity.
• Example 21 since ortho-cresol-modified phenol resin is used as the phenol resin, the mold strength is further improved, and the moisture absorption resistance is further improved. It has become.
• the organic binder in Comparative Example 9 to which such a reaction product is not added the organic binders in Comparative Examples 1 to 8 which are added in the basic silane compound alone or in the acid or its halide alone.
• the mold (test piece) obtained using a binder does not have sufficient mold strength in a normal humidity environment. Furthermore, the mold strength after moisture absorption deterioration is significantly reduced, and moisture absorption resistance is deteriorated. It is recognized that the mold is inferior in properties, and the mold obtained using such an organic binder is not practical.
• Example 22 After preparing the foundry sand composition in the same manner as in Example 18, the waiting time after kneading of the obtained foundry sand composition: 0 minutes and 120 minutes for the test piece (mold) molded from the test piece (mold) according to the measurement method and evaluation method, mold strength immediately and molding 24 hours after molding (kgf / cm 2), as well as mold strength after moisture absorption degradation of 24 hours after molding the (kgf / cm 2), were measured, respectively, The obtained results are shown in Table 6 below.
• Example 22 As the higher fatty acid ester, except that a polycondensate of ricinoleic acid and glycerin or a self-condensate of ricinoleic acid was further added to the organic binder in the ratio shown in Table 6 below, After preparing the foundry sand composition in the same manner as in Example 22, and waiting time after kneading of the obtained foundry sand composition: test pieces (molds) molded from those having 0 minutes and 120 minutes for, according to the measurement method and evaluation method described above, after molding, and mold strength after molding 24 hours (kgf / cm 2) and mold strength after moisture absorption degradation of 24 hours after molding the (kgf / cm 2), respectively measured The results obtained are shown in Table 6 below.
• Examples 31 to 35 Reaction obtained by reacting a basic silane compound (KBM602) and hydrofluoric acid as described above with respect to 100 parts by mass of the phenol resin solution prepared in the preparation (3) of the above phenol resin solution Product A was added in the proportions shown in Table 7 below, and stirred and mixed uniformly to prepare solution A according to each of Examples 31 to 35. Subsequently, while putting flattery sand into Dalton Co., Ltd.
• Examples 36 to 41, Comparative Example 12 When preparing the liquid A, the reaction product R of the basic silane compound (KBM602) and hydrofluoric acid was used together with the water content in the proportions shown in Tables 7 and 8 (the amount of water added in Tables 7 and 8 below).
• a casting sand composition was prepared in accordance with the same conditions and procedures as in Example 32 except that was added. And each test piece (mold) was produced using the obtained various foundry sand compositions, and the mold strength (kgf / cm 2 ) immediately after molding and 24 hours after molding according to the above measurement method. The mold strength (kgf / cm 2 ) after moisture absorption deterioration for 24 hours after molding was measured, and the obtained results are shown in Table 7 and Table 8 below.
• Example 42 In place of the phenol resin solution prepared in the preparation (3) of the phenol resin solution described above, except that the ortho-cresol-modified phenol resin solution prepared in the preparation (4) of the phenol resin solution was used, A foundry sand composition was prepared in the same manner as in Example 32. Then, using the obtained foundry sand composition, a test piece (mold) was prepared, and according to the above measurement method, the mold strength (kgf / cm 2 ) immediately after molding and 24 hours after molding, and after molding The mold strength (kgf / cm 2 ) after moisture absorption deterioration for 24 hours was measured, and the results are shown in Table 8 below.
• the solution is a solution containing a phenol resin and a reaction product R of a basic silane compound and hydrofluoric acid, and has a predetermined moisture content.
• a molding sand composition was prepared using an organic binder (Examples 31 to 42) composed of a solution (solution A) and a solution of a polyisocyanate compound (solution B), Furthermore, the mold (test piece) obtained by molding has excellent characteristics not only in mold strength under normal humidity environment but also in mold strength after moisture absorption deterioration under high humidity. It is recognized that Among these examples, in Example 42, since ortho-cresol-modified phenol resin is used as the phenol resin, the mold strength is further improved, and the moisture absorption resistance is further improved. It has become.
• Example 43 to 50 The ratio of the nonpolar organic solvent (Ipsol 150) used in the preparation of the polyisocyanate compound solution is set to the ratio shown in Table 9 below.
• the mold strength (kgf / cm 2 ) after moisture absorption deterioration for 24 hours after molding was measured, and the results are shown in Table 9 below. Further, using the foundry sand composition after waiting for 120 minutes from the kneading, the mold strength immediately after molding and after molding for 24 hours (kgf / cm 2 ), and the mold strength after deterioration of moisture absorption for 24 hours after molding (kgf / Cm 2 ) were measured, and the pot life was evaluated. The obtained results are shown in Table 9 below.

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