JPWO2018047893A1 - Resin composition for shell mold and resin coated sand obtained using the same - Google Patents

Abstract

There is provided a resin composition for shell mold which can improve the blocking resistance by enhancing the fusion point of RCS while improving the disintegration of the mold in a low temperature region, and for such a shell mold The resin composition is used to provide an RCS excellent in mold forming workability and in casting operation of a casting. In a resin composition for shell mold containing a phenol resin as a resin caking component, it is composed of one or two or more kinds of phosphoric acid ester compounds which do not contain a halogen bond in the molecule, and the P content is 14% or more And non-halogenated phosphoric acid esters having a viscosity of 150 mPa · s / 25 ° C. or higher.

Description

  The present invention relates to a resin composition for shell mold and a resin-coated sand obtained using the same, and in particular, a resin composition for shell mold that can improve the characteristics of the resin-coated sand used for molding of a mold The present invention relates to a resin-coated sand which can advantageously produce a mold having excellent properties obtained by using a resin composition for shell molding.

  Conventionally, in the shell mold method, a phenol resin composition containing a phenol resin as a resin caking component (binder component) is used as a caking agent, and it is kneaded with the refractory particles (aggregate / casting sand) After obtaining a resin coated sand (RCS) formed by forming a binder layer on the surface of such refractory particles by conducting this, a shell mold mold formed into a desired shape is generally used. It is coming.

  And in this type of mold, the mold may be easily disintegrated after such a casting operation, for example, to facilitate removal of the cast from the mold after the molten metal has been cast in. Conventionally, various measures have been taken, and, for example, in JP-A-11-244990 (Patent Document 1), a phosphoric acid ester, an oxidizing agent and an organic carboxylic acid metal are blended in a phenol resin. With the binder prepared as described above, RCS for molds obtained by coating the surface of sand grains is clarified. And, it has been clarified that a caking agent is prepared using tributyl phosphate as a phosphate ester, and the target RCS for template is produced. Molds obtained using RCS have problems such as low disintegration rate in the low temperature range lower than 350 ° C, slow curing speed at mold making, and insufficient blocking resistance of RCS, etc. doing.

  In addition, in JP 2007-275988 A (patent document 2), a resin composition for shell mold containing a phenol resin and an aromatic condensed phosphoric acid ester is clarified, and obtained using such a resin composition. It is believed that the mold produced by RCS improves the disintegration of the mold after casting. However, even with such a mold, there is a problem that the disintegration rate in a low temperature region lower than 350 ° C. is low, and the fusion point of RCS is low, which makes it easy to cause blocking of RCS. Furthermore, the curing speed at the time of mold making is slow, and there is an inherent risk of causing problems in moldability.

JP-A-11-244990 JP 2007-275988 A

  Here, the present invention is made on the background of such circumstances, and the problem to be solved by the present invention is that the fusion point of RCS is achieved while improving the disintegration of the mold in the low temperature range. It is an object of the present invention to provide a resin composition for shell mold which can improve the blocking resistance advantageously, and using such a resin composition for shell mold, molding workability and mold casting of molds. It is to provide RCS excellent in workability.

  Then, as a result of intensive investigations on the resin composition for shell mold in order to solve the problems as described above, the present inventors have found that the phenol resin does not contain halogen in the molecule, and that the phenol resin is specific. Melting of RCS obtained using such a resin composition as a caking agent by constructing a resin composition for shell mold by combining P content and non-halogenated phosphoric acid esters having a specific viscosity It has been found that the point of attachment can be effectively enhanced, and that the disintegratability in the low temperature range of the template obtained using such RCS can be advantageously enhanced, and the present invention has been completed. is there.

  That is, the present invention has been completed based on the above-described findings, and the gist is that in a shell mold resin composition containing a phenol resin as a resin caking component, halogen is contained in the molecule. It further contains non-halogenated phosphoric acid esters consisting of one or two or more kinds of phosphoric acid ester compounds not containing bonds, and having a P content of 14% or more and a viscosity of 150 mPa · s / 25 ° C. or more It is a resin composition for shell mold characterized by being formed.

  According to one of the desirable embodiments of such a resin composition for shell mold according to the present invention, a configuration in which at least one of the phosphoric acid ester compounds is an aliphatic condensed phosphoric acid ester is adopted. Become.

  Further, according to another desirable aspect of the present invention, the non-halogenated phosphoric acid ester comprises 80% by mass or more of an aliphatic condensed phosphoric acid ester and 20% by mass or less of an aromatic phosphoric acid ester and / or an aromatic group. It is composed of condensed phosphoric acid ester.

  Furthermore, in the resin composition for shell mold according to the present invention, preferably, the non-halogen based phosphate ester is contained in a ratio of 1 to 50 parts by mass with respect to 100 parts by mass of the phenol resin. .

  In the present invention, novolac type phenol resin and / or resol type phenol resin are advantageously used as the phenol resin, and there is also a case where novolac type phenol resin and resol type phenol resin are used in combination. In this case, the use ratio of the novolac type phenol resin (A) to the resol type phenol resin (B) is configured such that A: B = 95: 5 to 5:95 on a mass basis.

  In the present invention, the resin composition for a shell mold as described above is used as a caking agent, and the surface of the fireproof aggregate is covered with the layer of the caking agent. The target is resin coated sand (RCS).

  Moreover, in such RCS, a lubricant is desirably contained in the binder layer, and / or a silane coupling agent is contained.

  Thus, in the resin composition for shell mold according to the present invention, it is composed of at least one kind of halogen-free phosphoric acid ester compound together with a predetermined phenol resin, and a specific P content and a specific viscosity. Containing non-halogen based phosphoric acid esters, when such a resin composition is used as a binder, the strength of the mold formed from the RCS obtained in the production of RCS The fusion point of such RCS could be effectively increased without lowering the strength of the RCS, and the blocking resistance of such RCS could be advantageously improved, and additionally, molding was carried out using such RCS. It is also possible to advantageously improve the disintegratability of the mold obtained in the low temperature region.

  Moreover, a coating of a caking agent comprising the resin composition for a shell mold according to the present invention is applied, in other words, a mold is formed using RCS in which such a caking agent layer is formed on the surface of refractory particles. Since the curing speed of the mold to be molded can be effectively enhanced in forming the mold, the handling property is effectively improved in molding of the mold using such RCS, and thus the mold Since the molding temperature and molding time do not have to be changed variously to obtain the target mold characteristics, the molding workability can be advantageously enhanced.

  By the way, in the resin composition for shell mold according to the present invention, the phenol resin contained as the resin caking component (binder component) is, as is well known, an acid catalyst or basicity between phenols and aldehydes Novolak type or resole, which is a solid or liquid (including varnish or emulsion form) condensation product obtained by reacting in the presence of a catalyst, depending on the type of catalyst used therein. It is a phenolic resin which is referred to as a mold and which exhibits thermosetting when heated in the presence or absence of a predetermined curing agent or curing catalyst.

  In addition, phenols used as a raw material of such phenol resin mean phenol and derivatives of phenol, and for example, in addition to phenol, alkylphenols such as cresol, xylenol, p-tert-butylphenol, nonylphenol and the like And resorcinol, polyphenols such as bisphenol F, bisphenol A and mixtures thereof and the like and known ones, and one of them may be used alone or in combination of two or more. It will be

  Examples of aldehydes include paraformaldehyde, trioxane, acetaldehyde, paraaldehyde, propionaldehyde and the like in addition to formalin in the form of an aqueous solution of formaldehyde, and other known aldehyde compounds may be appropriately selected. It can be used. And even if it is used independently, and these aldehydes are used in combination of 2 or more types, there is no difference at all.

  Here, the novolac type phenol resin used in the present invention is an acidic catalyst such as an inorganic acid such as hydrochloric acid, sulfuric acid or phosphoric acid, as is well known using the above-mentioned phenols and aldehydes, It is formed by condensation reaction with an organic acid such as oxalic acid, p-toluenesulfonic acid, benzenesulfonic acid, xylenesulfonic acid and the like, and further an acidic substance such as zinc oxide, zinc chloride, magnesium oxide and zinc acetate . In this case, the compounding molar ratio (F / P) of the aldehyde (F) and the phenol (P) is appropriately selected depending on the type of reaction catalyst used, etc., but is preferably It will be selected in the range of 0.55 to 0.80.

  On the other hand, the resol-type phenol resin is formed by subjecting the above-mentioned phenols and aldehydes to a condensation reaction with a known basic catalyst in the same manner as in the prior art. As the basic catalyst, hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide and calcium hydroxide, and oxides of alkaline earth metals can be used, and in addition, dimethylamine, triethylamine, butylamine It is possible to use amines such as dimethylbenzylamine and naphthalenediamine, ammonia, hexamethylenetetramine, naphthenic acid salts of other divalent metals, hydroxides of divalent metals, and the like. Moreover, although the compounding molar ratio (F / P) of the aldehydes and phenols in such a condensation reaction is suitably selected according to the kind etc. of the reaction catalyst used there, generally 1.1- It will be selected within the range of 4.0.

  And, in the resin composition for shell mold according to the present invention, both of the novolak type phenol resin and the resol type phenol resin obtained as described above are advantageously used together as the resin caking component. There, such resol-type phenolic resin is made to function as a curing agent for novolac-type phenolic resin and also as a component capable of improving characteristics such as bending strength of the mold. In addition, when using the novolac type phenol resin (A) and the resol type phenol resin (B) in combination, the ratio of their use is such that A: B = 95: 5 to 5:95 on a mass basis. In particular, a use ratio within the range of A: B = 30: 70 to 70:30, and in particular 40:60 to 60:40 will be advantageously adopted.

  In addition, when using these novolak-type phenol resin and resol-type phenol resin together, the use ratio of resol-type phenol resin exceeds 95 mass% with respect to the total amount of novolak-type phenol resin and resol-type phenol resin, Therefore, when the use ratio of the novolac type phenol resin is less than 5% by mass, it is difficult to uniformly mix the two types of phenol resins when they are mixed and used, and therefore the resin composition for shell mold ( A problem is caused that the strength of the mold as a whole is reduced. Also, conversely, when the use ratio of resol type phenol resin is less than 5% by mass and the use ratio of novolac type phenol resin exceeds 95% by mass, novolak can not be cured with the resol type phenol resin. Of the curing speed due to the fact that the amount of the phenolic resin increases and the excess novolac phenolic resin remains without curing, making it difficult to achieve complete curing of the shell mold resin composition (caking agent). There is a risk of

  Also, in the resin composition for shell mold according to the present invention, halogen-free non-halogenated phosphoric acid esters are contained together with the above-mentioned phenolic resin, in which non-halogenated phosphoric acid esters are Or one or more kinds of halogen-free phosphoric acid ester compounds in which halogen (atom) is not contained in a bond in the molecule. Such non-halogen phosphates are used to mold a mold using RCS, which uses the resin composition for shell mold as a caking agent, or cast molten metal using the mold that has been molded. In this case, even if such non-halogenated phosphoric acid esters are decomposed, halogen compounds are not generated, and there is also a fear that the mold and peripheral devices may be corroded by the halogen compounds generated by the decomposition. It is possible to enjoy advantages such as not being triggered.

And in the present invention, among such non-halogenated phosphoric esters, the P (phosphorus element) content is 14% or more, preferably 15% or more, more preferably 18% or more and 30% or less, and With a viscosity of 150 mPa · s / 25 ° C. or more, preferably 300 mPa · s / 25 ° C. or more, more preferably 500 mPa · s / 25 ° C. or more, still more preferably 800 mPa · s / 25 ° C. or more and 3000 mPa · s / 25 ° C. or less It is necessary to use something. Here, the P content (%) in the halogen-free phosphoric acid ester compound is specifically calculated by the following formula.
P content (%) = [(atomic weight of phosphorus element in substance × number of phosphorus elements)
/ (Molecular weight of substance)] × 100

  In addition, if non-halogenated phosphates having a P content of less than 14% are used, the disintegratability of the template is affected, and problems such as insufficient disintegration rate in a low temperature range are caused. Become. In addition, in the case of using a non-halogenated phosphoric acid ester having a viscosity of less than 150 mPa · s / 25 ° C., the fusion bonding point of RCS is lowered and blocking of RCS tends to be caused, and template molding is formed. As the curing speed at the time decreases, problems such as deterioration of workability in molding are caused.

  In addition, it is desirable that at least one kind of phosphoric acid ester compound constituting the non-halogenated phosphoric acid esters used in the present invention is an aliphatic condensed phosphoric acid ester, in which aliphatic condensed phosphoric acid ester is used. Preferably, it is constituted so as to be contained 80% by mass or more, more preferably 90% by mass or more of non-halogenated phosphoric acid esters. Thus, although the mechanism of the influence on the disintegration of the template by constituting the halogen-free phosphoric acid esters mainly composed of the aliphatic condensed phosphoric acid ester has not been elucidated yet, such aliphatic It has been found that the use of condensed phosphoric acid esters, in particular, results in a very high degradation of the template in the low temperature range (300-350 ° C.).

  Moreover, in the present invention, it is recommended to use, in combination with the above-mentioned aliphatic condensed phosphoric acid ester, at least one of aromatic phosphoric acid ester and aromatic condensed phosphoric acid ester. Thus, the inclusion of the aromatic phosphoric acid ester and / or the aromatic condensed phosphoric acid ester together with the aliphatic condensed phosphoric acid ester advantageously enhances the disintegration of the template in a high temperature range (400 ° C. or higher). It is possible. In addition, as long as the P content of the non-halogen phosphates is 14% or more and the viscosity is 150 mPa · s / 25 ° C. or more, the aromatic phosphate and the aromatic condensed phosphate are preferable. And the aliphatic phosphoric acid ester may be blended and contained as one component of the non-halogenated phosphoric acid ester without causing any problem even if it is contained as one component of the non-halogenated phosphoric acid ester in combination with Is also possible. Here, it is needless to say that none of the aromatic phosphoric acid ester, the aromatic condensed phosphoric acid ester and the aliphatic phosphoric acid ester contains halogen (atom) in the molecule thereof.

  Thus, in the case where the non-halogenated phosphoric acid esters are composed of plural kinds of phosphoric acid ester compounds, the P content (%) is the same as the P content (%) of each phosphoric acid ester compound. It will be calculated | required as a sum of the numerical value obtained by multiplying the mixture ratio of each phosphoric acid ester compound, respectively. In addition, the viscosity (25 ° C.) of the non-halogen based phosphoric acid esters composed of such plural kinds of phosphoric acid ester compounds can be determined by actually measuring.

［但し、式中、Ｒ₁ は、炭素数が１〜４のアルキル基を示し、全てのＲ₁ が同一であっても、異なっていてもよい。Ｘは、炭素数が１〜３のアルキレン基を示し、ｎは、１〜１０の整数を表す。］
また、その他、市場から入手されて、脂肪族縮合リン酸エステルとして用いられ得るものとして、「ＤＡＩＧＵＡＲＤ−８８０」（大八化学工業株式会社製）等を挙げることが出来る。By the way, the aliphatic condensed phosphoric acid ester suitably used in the present invention is an alkyl phosphate exhibiting an oligomer form, and specifically, an oligomer ethyl ethylene phosphate, a modified oligomer ethyl ethylene phosphate, an oligomer ethyl ethylene phosphate as a main component Formulations and the like can be mentioned, and such aliphatic condensed phosphoric esters are also commercially available. For example, “Fyrol PNX” (manufactured by ICL JAPAN Co., Ltd.), “Fyrol PNX-LE” ICL JAPAN Co., Ltd.), "Fyrol HF-5" (ICL JAPAN Co., Ltd.), etc. are obtained from the market and will be used. In addition, it is also possible to show such aliphatic condensed phosphoric acid ester conceptually by following formula 1.

[Wherein, in the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms, and all R _{1 's} may be the same or different. X shows a C1-C3 alkylene group, n represents the integer of 1-10. ]
In addition, "DAIGUARD-880" (made by Daihachi Chemical Industry Co., Ltd.) etc. can be mentioned as what is obtained from a market and can be used as an aliphatic condensed phosphoric acid ester.

  In addition, specific examples of the aromatic phosphoric acid ester used in combination with the above-mentioned aliphatic condensed phosphoric acid ester include triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, 2- Ethylhexyl diphenyl phosphate, t-butyl phenyl diphenyl phosphate, bis (t- butyl phenyl) phenyl phosphate, tris (t- butyl phenyl) phosphate, isopropyl phenyl diphenyl phosphate, bis (isopropyl phenyl) diphenyl phosphate, tris (isopropyl) Phenyl) phosphate etc. can be mentioned. Furthermore, as the aromatic condensed phosphoric acid ester, specifically, phenylene bis (phenyl cresol phosphenate), 2,2-bis {4- [bis ((mono or di) methyl phenoxy) phosphoryloxy] phenyl} Propane, 1,3-phenylenebis (dixylenyl) phosphate, α-diphenoxyphosphoryl-ω-phenoxypoly (n = 1 to 3) [oxy-1,4-phenyleneisopropylidene-1,4-phenyleneoxy (phenoxyphosphoryl) In the market, select commercial products such as “CR-733S”, “CR-747”, “PX-200” and “CR-741” manufactured by Daihachi Chemical Industry Co., Ltd. Can be used.

  Furthermore, as an aliphatic phosphate ester as a component to be used in combination with an aliphatic condensed phosphate ester, specifically, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, methyl diethyl phosphate, methyl dibutyl phosphate, ethyl dibutyl phosphate Mention may be made of trialkyl phosphates such as phosphate.

  And, in the resin composition for shell mold according to the present invention, the non-halogenated phosphoric acid ester as described above is generally 2 to 30 parts by weight, preferably 2 to 30 parts by weight with respect to 100 parts by weight of the phenol resin. It will be used in the ratio of a mass part, more preferably 3-20 mass parts. When the amount of the non-halogenated phosphate ester used is too small, the characteristic effects of the present invention, in particular, the disintegrability improving effect can not be sufficiently obtained, and when the amount used is too large, There is a possibility that the curing speed at the time of mold making may be reduced, and the fusion point of RCS may be lowered to cause blocking easily, and there may also be a possibility that the amount of smoke generated at the time of molding increases.

  In addition, in order to obtain the resin composition for shell mold according to the present invention, various methods of adding the above-mentioned non-halogenated phosphoric acid esters to the phenol resin are based on the knowledge of those skilled in the art. For example, non-halogenated phosphoric acid esters may be added at the time of production of a phenolic resin, or non-halogenated phosphoric acid esters may be added after the production of such a phenolic resin to obtain an objective shell mold. In addition to the method of using a resin composition, at the time of production of RCS, a non-halogen based phosphate ester is added separately from the phenol resin (resin composition for shell mold) to coat the surface of the refractory particles. It is also possible to adopt a method in which non-halogenated phosphoric acid esters are introduced into the binder layer.

  Furthermore, in the resin composition for a shell mold according to the present invention, various additives generally used conventionally for the purpose of improving the physical properties of RCS and mold, etc. may be appropriately blended if necessary. Is possible. For example, as lubricants contributing to the improvement of fluidity of RCS, waxes such as paraffin wax, synthetic polyethylene wax, montanic acid wax; fatty acid amides such as stearic acid amide, oleic acid amide and erucic acid amide; methylene bis stearin Acid amides, alkylene fatty acid amides such as ethylenebisstearic acid amide; stearic acid, stearyl alcohol, stearic acid metal salt, lead stearate, zinc stearate, calcium stearate, magnesium stearate, monostearate monoglyceride, stearyl stearate, cured It is possible to add oils and the like. In addition, it is also effective to incorporate a coupling agent that strengthens the bond between the refractory particles and the resin composition for shell mold, for example, using a silane coupling agent, a zircon coupling agent, a titanium coupling agent, etc. Can do. In addition, as a mold release agent, paraffin, wax, light oil, machine oil, spindle oil, insulating oil, waste oil, vegetable oil, fatty acid ester, organic acid, graphite fine particles, mica, vermiculite, fluorine-based mold release agent, silicone-based release agent A mold agent etc. can also be used. Each of these additives is used in a proportion of about 0.1 to 10 parts by mass, preferably about 0.5 to 5 parts by mass, with respect to 100 parts by mass of the phenol resin. In addition, these additives may be added at the time of manufacture of the resin composition for shell molds, and even if it is separately added and compounded with the resin composition for shell molds at the time of manufacture of RCS, there is no problem.

  By the way, when manufacturing RCS for shell molds using the resin composition for shell molds which is mentioned above, the resin composition for shell molds with respect to a predetermined | prescribed refractory particle (aggregate) according to a conventional method It will be kneaded. In addition, the compounding amount of the resin composition for shell mold according to the present invention is determined appropriately in consideration of the type of resin to be used, the strength of the mold required, etc. Although it may not be defined as such, generally, it is in the range of about 0.2 to 10 parts by mass, preferably 0.5 to 8 parts by mass, with respect to 100 parts by mass of the refractory particles. More preferably, it is in the range of 1 to 5 parts by mass.

  In addition, as the refractory particles (aggregate) to which such a resin composition for shell mold is kneaded, conventionally known particles can be appropriately selected and used, and the type thereof is the same as that of the present invention. It is not particularly limited as long as it is. Since such refractory particles form the substrate of the mold, any inorganic refractory particles having a particle size that is suitable for casting resistance and mold formation (forming) can be conventionally used. Any of the known inorganic particles that have been used for shell mold casting may be used. And as such refractory particles, for example, in addition to generally used borax, special sand such as olivine sand, zircon sand, chromite sand, alumina sand, ferrochrome-based slag and ferronickel-based sand Slag, slag-based particles such as converter slag, mullite-based artificial particles such as naigai sera beads (trade name: Itochu Celatech Co., Ltd.), or regenerated particles obtained by recovering and regenerating them after casting However, they may be used alone or in combination of two or more.

  And when manufacturing target RCS using the resin composition for shell molds according to this invention, the manufacturing method is not specifically limited, A dry hot coat method, a semi hot coat method, a cold coat method, Although any of the conventionally known methods such as the powder solvent method may be employed, in the present invention, the refractory particles and shell mold preheated in a kneader such as a whirl mixer or a speed mixer are particularly used. For example, an aqueous solution of a predetermined curing agent such as hexamethylenetetramine or a curing accelerator is added after kneading with the resin composition (resin caking component), and the massive content is separated into particles by blast cooling, It is recommended to use a so-called dry hot coat method to add calcium phosphate (lubricant). In addition, the timing which knead | mixes the resin caking component (phenol resin) and hardening | curing agent / hardening accelerator which comprise the resin composition for shell molds according to this invention with refractory particle | grains is suitably selected based on knowledge of those skilled in the art. In addition to being sequentially kneaded alone, it is also possible to appropriately combine and knead.

  Furthermore, when forming a predetermined mold such as a shell mold mold using the RCS obtained as described above, the target mold is formed under heating to achieve heat curing of the RCS. However, such a heating and molding method is not particularly limited, and any conventionally known method can be advantageously used. For example, RCS as described above is filled and cured in a mold heated to about 150 ° C. to 300 ° C. having a desired shape space for giving a target mold by a gravity drop method, a blowing method, or the like. Thereafter, the target casting mold can be obtained by removing the hardened mold from the mold. And, in the mold thus obtained, the excellent characteristics as described above can be advantageously imparted.

  In the following, some examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by any description of such examples. Is, of course. In addition to the specific examples described above, the present invention also includes various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the specific description described above. It should be understood that improvements, etc. may be added. The parts and percentages in the following examples and comparative examples are all expressed on a mass basis, and the measurement of the fusion point of RCS, the amount of bend (300 gf) and the collapse rate are as follows. I went to.

-Measurement of RCS fusion point-
The fusion temperature of each RCS is measured in accordance with JACT test method: C-1 (fusion point test method). That is, an RCS to be measured is spread quickly on a metal rod having a temperature gradient, and after 60 seconds, a 1.0 mm diameter nozzle moving along a guide rod at a position 10 cm away from the metal rod Then, while blowing air at an air pressure of 0.1 MPa, the nozzle is reciprocated one turn from the low temperature portion to the high temperature portion of the metal rod to blow off the RCS on the metal rod. Then, the temperature of the boundary between the blown RCS and the non-blown RCS is read up to 1 ° C. by such air blowing to determine the fusion point (° C.) of the RCS to be measured. The higher the measured fusion temperature, the better the blocking resistance of RCS.

-Measurement of the amount of bend (300 gf)-
Each test piece (180 mm x 40 mm x 5 mm, baking conditions: 250 degreeC x 40 seconds) obtained from each RCS was used. Except for the dimensions of the test piece, the amount of strain in the central portion of the test piece after a load of 300 gf is applied to the central portion according to the procedure of the JACT test method: SM-3 deflection test method and left for 3 minutes Read mm) with a dial gauge, and let that value be the amount of bend (300 gf). The amount of bending (the amount of bending) is a standard index showing the handling property immediately after mold making and mold curing speed, and the smaller the bend amount, the faster the mold curing speed and the better the handling property. There is.

-Measurement of disintegration rate-
A JIS-type test piece (width: 10 mm × thickness: 10 mm × length: 60 mm, baking time: 250 ° C. × 60 seconds) is produced from each RCS according to JIS-K-6910, and the obtained JIS type The test pieces (5 pieces) are wrapped in double aluminum foil and then placed in a drying oven at a predetermined temperature (300 ° C., 350 ° C. or 400 ° C.) and heated for 30 minutes. Thereafter, the test piece is taken out and cooled to room temperature, and then the flexural strength is measured. Using this measurement value and the measurement value of the bending strength of the test piece (5 pieces) at room temperature, the decay rate (%) for each RCS is calculated from the respective average values according to the following equation.
Disintegration rate (%) = [{Bending strength at normal temperature-bending strength after treatment for 30 minutes at a predetermined temperature (300 ° C, 350 ° C or 400 ° C)} / bending strength at normal temperature] × 100

<Production of Novolak-type Phenolic Resin>
-Resin production example 1-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to be reacted, and further, the reaction solution is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. Parts of a phenolic resin A1 were obtained.

-Resin production example 2-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to make a reaction, and the reaction liquid is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. 95 parts of condensed phosphoric acid ester (trade name: Fyrol HF-5, manufactured by ICL JAPAN Co., Ltd.) (P content 14%, viscosity 900 mPa · s / 25 ° C.) was added to obtain 945 parts of novolac type phenol resin A2 .

-Resin production example 3-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to make a reaction, and the reaction liquid is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. Novolak-type phenolic resin added with 95 parts of condensed phosphoric ester (main component: oligomer ethyl ethylene phosphate, trade name: Fyrol PNX, manufactured by ICL JAPAN Co., Ltd.) (P content 19%, viscosity 1000 mPa · s / 25 ° C.) Obtained 945 parts of A3.

-Resin production example 4-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to make a reaction, and the reaction liquid is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. 95 parts of condensed phosphoric acid ester (trade name: Fyrol PNX-LE, manufactured by ICL JAPAN Co., Ltd.) (P content 19%, viscosity 2250 mPa · s / 25 ° C.) was added to obtain 945 parts of novolac type phenol resin A4 .

-Resin production example 5-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to make a reaction, and the reaction liquid is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. Novolak-type phenol resin A5 with 95 parts of condensed phosphoric acid ester (trade name: DAIGUARD-880, manufactured by Daihachi Chemical Industry Co., Ltd.) (P content: 15.5%, viscosity 150 to 350 mPa · s / 25 ° C) 945 parts were obtained.

Resin Production Example 6
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to make a reaction, and the reaction liquid is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. 76 parts of condensed phosphoric acid ester (main component: oligomeric ethyl ethylene phosphate, trade name: Fyrol PNX, manufactured by ICL JAPAN Co., Ltd.) and t-butylphenyl diphenyl phosphate (BPDP) which is an aromatic phosphoric acid ester (P content 19 parts of 8.1% and viscosity 65-75 mPa * s / 25 degreeC) were added, and 945 parts of novolak-type phenol resin A6 were obtained. The P content of the non-halogenated phosphoric acid esters composed of the two types of phosphoric acid esters used here is 16.82%, and the measured value of viscosity (at 25 ° C.) is 820 mPas.・ It was s.

-Resin production example 7-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to make a reaction, and the reaction liquid is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. 76 parts of condensed phosphoric ester (main component: oligomer ethyl ethylene phosphate, trade name: Fyrol PNX, manufactured by ICL JAPAN Co., Ltd.), and triphenyl phosphate (TPP) which is an aromatic phosphoric acid ester (P content 9.5 19 parts (solid) was added to obtain 945 parts of novolac type phenol resin A7. The P content of the non-halogenated phosphoric acid esters composed of the two types of phosphoric acid esters used here is 17.1%, and the measured value of viscosity (25 ° C.) is about It was 1000 mPa · s.

-Resin production example 8-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to make a reaction, and the reaction liquid is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. 76 parts of condensed phosphoric acid ester (main component: oligomer ethyl ethylene phosphate, trade name: Fyrol PNX, manufactured by ICL JAPAN Co., Ltd.), and aromatic condensed phosphoric acid ester [main component: phenylene bis (phenyl cresol phosphenate), Trade name: CR-733S, manufactured by Daihachi Chemical Industry Co., Ltd.] (P content: 10.9%, viscosity: 600 mPa · s / 25 ° C.) was added to obtain 945 parts of novolac type phenolic resin A8. The P content of the non-halogenated phosphoric acid esters composed of the two kinds of phosphoric acid esters used here is 17.38%, and the measured value of viscosity (25 ° C.) is 860 mPas.・ It was s.

-Resin production example 9-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and the reaction vessel is refluxed for 90 minutes to make a reaction, and the reaction liquid is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. 76 parts of condensed phosphoric ester (main component: oligomer ethyl ethylene phosphate, trade name: Fyrol PNX, manufactured by ICL JAPAN Co., Ltd.), and aliphatic phosphate (triethyl phosphate, trade name: TEP, Daihachi Chemical Industry Co., Ltd. 19 parts of (P content 17%, viscosity 1.6 mPa · s / 25 ° C.) was added to obtain 945 parts of novolac type phenol resin A9. Incidentally, the P content of the non-halogenated phosphoric acid esters composed of the two types of phosphoric acid esters used here is 18.6%, and the measured value of viscosity (at 25 ° C.) is 790 mPas.・ It was s.

-Resin production example 10-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and then the reaction is carried out under reflux for 90 minutes, and the reaction solution is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. Condensed phosphoric acid ester [main component: phenylene bis (phenyl cresol phosphenate), trade name: CR-733S, manufactured by Daihachi Chemical Industry Co., Ltd.] (P content: 10.9%, viscosity: 600 mPa · s / 25 ° C) 95 parts of novolak-type phenol resin A10 were obtained.

-Resin production example 11-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised to reach the reflux temperature, and then the reaction is carried out under reflux for 90 minutes, and the reaction solution is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. 95 parts of phosphoric acid ester t-butylphenyl diphenyl phosphate (BPDP) (P content: 8.1%, viscosity: 65 to 75 mPa · s / 25 ° C.) was added to obtain 945 parts of novolac type phenolic resin A11.

-Resin production example 12-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised, and after reaching the reflux temperature, the reaction mixture is refluxed for 90 minutes to make a reaction, and the reaction solution is concentrated under reduced pressure while heating until the temperature reaches 170 ° C. 95 parts of acid ester triphenyl phosphate (TPP) (P content: 9.5%, solid) was added to obtain 945 parts of novolac type phenol resin A12.

-Resin production example 13-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 940 parts of phenol, 428 parts of 47% formalin, and 2.8 parts of oxalic acid were charged, respectively. Then, the temperature of the reaction vessel is gradually raised, and after reaching the reflux temperature, the reaction mixture is refluxed for 90 minutes to be reacted, and the reaction liquid is subjected to vacuum concentration while heating until the temperature reaches 170 ° C. Add 95 parts of acid ester (triethyl phosphate, trade name: TEP, manufactured by Daihachi Chemical Industry Co., Ltd.) (P content: 17%, viscosity: 1.6 mPa · s / 25 ° C), and 945 parts of novolac type phenol resin A13 Obtained.

<Manufacture of resol type phenolic resin>
-Resin production example 14-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 680 parts of phenol, 535 parts of 47% formalin, and 101 parts of hexamethylenetetramine are charged, respectively, and the temperature is raised to 70 ° C. in about 60 minutes. The reaction was left as it was for 5 hours. Thereafter, the reaction liquid was dehydrated under reduced pressure while heating to 90 ° C. to obtain 700 parts of resol-type phenol resin B1.

-Resin production example 15-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 680 parts of phenol, 535 parts of 47% formalin, and 101 parts of hexamethylenetetramine are charged, respectively, and the temperature is raised to 70 ° C. in about 60 minutes. The reaction was left as it was for 5 hours. Thereafter, the reaction liquid is dehydrated under reduced pressure while heating to 90 ° C., and then 78 parts of an aliphatic condensed phosphoric ester (trade name: Fyrol HF-5, manufactured by ICL JAPAN Co., Ltd.) is added to obtain a resol type phenol resin. 778 parts of B2 were obtained.

-Resin production example 16-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 680 parts of phenol, 535 parts of 47% formalin, and 101 parts of hexamethylenetetramine are charged, respectively, and the temperature is raised to 70 ° C. in about 60 minutes. The reaction was left as it was for 5 hours. Thereafter, the reaction solution is subjected to reduced pressure dehydration while heating to 90 ° C., and then 78 parts of an aliphatic condensed phosphoric ester (trade name: Fyrol PNX, manufactured by ICL JAPAN Co., Ltd.) is added to obtain resol type phenol resin B3. 778 parts were obtained.

-Resin production example 17-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 680 parts of phenol, 535 parts of 47% formalin, and 101 parts of hexamethylenetetramine are charged, respectively, and the temperature is raised to 70 ° C. in about 60 minutes. The reaction was left as it was for 5 hours. Thereafter, the reaction liquid is dehydrated under reduced pressure while heating to 90 ° C., and then 78 parts of an aliphatic condensed phosphoric acid ester (trade name: Fyrol PNX-LE, manufactured by ICL JAPAN Co., Ltd.) is added to obtain a resol type phenol resin. 778 parts of B4 were obtained.

-Resin production example 18-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 680 parts of phenol, 535 parts of 47% formalin, and 101 parts of hexamethylenetetramine are charged, respectively, and the temperature is raised to 70 ° C. in about 60 minutes. The reaction was left as it was for 5 hours. Thereafter, the reaction solution is dehydrated under reduced pressure while heating to 90 ° C., and then 78 parts of an aliphatic condensed phosphoric acid ester (trade name: DAIGUARD-880, manufactured by Daihachi Chemical Industry Co., Ltd.) is added, and resol type phenol is added. 778 parts of resin B5 were obtained.

-Resin production example 19-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 680 parts of phenol, 535 parts of 47% formalin, and 101 parts of hexamethylenetetramine are charged, respectively, and the temperature is raised to 70 ° C. in about 60 minutes. The reaction was left as it was for 5 hours. Thereafter, the reaction liquid is dehydrated under reduced pressure while heating to 90 ° C., and then 62.4 parts of an aliphatic condensed phosphoric acid ester (trade name: Fyrol PNX, manufactured by ICL JAPAN Co., Ltd.), and an aromatic phosphoric acid ester 15.6 parts of t-butylphenyl diphenyl phosphate (BPDP) which is the above were added to obtain 778 parts of resol-type phenol resin B6. The P content of the non-halogenated phosphoric acid esters composed of the two types of phosphoric acid esters used here is 16.82%, and the measured value of viscosity (at 25 ° C.) is 820 mPas.・ It was s.

-Resin production example 20-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 680 parts of phenol, 535 parts of 47% formalin, and 101 parts of hexamethylenetetramine are charged, respectively, and the temperature is raised to 70 ° C. in about 60 minutes. The reaction was left as it was for 5 hours. Thereafter, the reaction liquid is dehydrated under reduced pressure while heating to 90 ° C., and then aromatic condensed phosphoric acid ester [main component: phenylene bis (phenyl cresol phosphenate), trade name: CR-733S, Daihachi Chemical Industry Co., Ltd. Then, 78 parts of Rezole-type phenol resin B7 was obtained by adding 78 parts of a product manufactured by K. K.

-Resin production example 21-
In a reaction vessel equipped with a thermometer, a stirrer and a condenser, 680 parts of phenol, 535 parts of 47% formalin, and 101 parts of hexamethylenetetramine are charged, respectively, and the temperature is raised to 70 ° C. in about 60 minutes. The reaction was left as it was for 5 hours. Thereafter, the reaction liquid is dehydrated under reduced pressure while heating to 90 ° C., and then 78 parts of aromatic phosphate ester t-butylphenyl diphenyl phosphate (BPDP) is added to obtain 778 parts of resol type phenolic resin B8 The

<Production of RCS>
-Example 1-Example 8-
After adding 105 parts of any of the above novolak-type phenol resins A2 to A9 to 7000 parts of new sand (natural borax from Australia, brand name: Fluttery) heated to 150 ° C. and kneading with a speed mixer for 50 seconds, A solution of 15.75 parts of hexamethylenetetramine in 105 parts of water is added, and the mixture is kneaded until the sand is separated into individual particles, and 7 parts of calcium stearate (manufactured by Nippon Oil & Fats Co., Ltd.) After adding and mixing for 15 seconds, RCS1-8 were respectively obtained by discharging from the mixer. And about this obtained RCS1-8, measurement of a fusion | melting point, measurement of a bend (300 gf) amount, and measurement of a decay rate are implemented, respectively, and those test results are shown in following Table 1.

-Example 9-Example 13-
RCSs 9 to 13 in the same manner as in Example 1 except that 52.5 parts of novolac-type phenol resin A1 and 52.5 parts of each of novolac-type phenol resins A2 to A6 were used in Example 1. I got each. Then, using the obtained RCSs 9 to 13, the measurement of the fusion point, the measurement of the amount of bend (300 gf), and the measurement of the disintegration rate were carried out, respectively, and the obtained results are shown in Table 2 below.

Example 14 to Example 18
In 7,000 parts of new sand (natural borax from Australia, brand name: Fluttery) heated to 150 ° C., 52.5 parts of the above novolak type phenolic resin A2 to A6 and 52.5 parts of the above resol type phenolic resin B2 to B6 Are mixed until the sand is separated into individual particles by a speed mixer, and 7 parts of calcium stearate (manufactured by NOF Corporation) is added and mixed for 15 seconds, and then By discharging, RCS 14-18 were obtained, respectively. And the measurement of a fusion | melting point, the measurement of a bend (300 gf) amount, and the measurement of a decay rate were implemented using the obtained RCS14-18, respectively, and the obtained result is shown in following Table 2 and Table It is shown in 3.

-Example 19 to Example 23-
In Example 14, 26.25 parts of novolac type phenol resin A1, 26.25 parts of each of novolak type phenol resins A2 to A6, 26.25 parts of resol type phenol resin B1, and resol type phenol resin B2 RCSs 19 to 23 were obtained in the same manner as in Example 14 except that 26.25 parts of each of B6 to B6 was used. And about each obtained RCS 19-23, the measurement of a fusion | melting point, the measurement of a bend (300 gf) amount, and the measurement of a decay rate are implemented, and the obtained result is shown in following Table 3.

Comparative Example 1 to Comparative Example 5
RCS24-28 were obtained respectively similarly to Example 1 except having replaced novolak-type phenol resin A2 with novolak-type phenol resin A1 and A10-A13 in Example 1. FIG. And about this obtained RCS24-28, a measurement of a fusion | melting point, a measurement of a bend (300 gf) amount, and a measurement of a decay rate are performed, respectively, and the obtained result is shown in following Table 4.

Comparative Example 6 to Comparative Example 8
Example 14 is the same as Example 14 except that novolac-type phenol resin A2 is replaced with novolak-type phenol resin A1, A10 or A11 and resol-type phenol resin B2 is replaced with resol-type phenol resin B1, B7 or B8. Similarly, RCS 29 to 31 were obtained, respectively. And about this obtained RCS29-31, a measurement of a fusion | melting point, a measurement of a bend (300gf) amount, and a measurement of a decay rate are performed, respectively, and the obtained result is shown in following Table 4.

  As is clear from the results of Tables 1 to 4 above, all of RCSs 1 to 23 obtained in Examples 1 to 23 have high fusion points and small amounts of bends, so that the mold curing speed is high and handling While showing good quality, it showed excellent results in the rate of decay in the low temperature region. On the other hand, in the case where the phosphoric acid ester as an additive is not blended as in Comparative Examples 1 and 6, the disintegrability is bad, and as in Comparative Examples 2 to 5 and 7 to 8 in the present invention, In the case where only aliphatic phosphate ester and aromatic phosphate ester which are out of the specified P content and viscosity range are blended, although the disintegrability is improved, the effect as in the embodiment according to the present invention is not obtained. There is a problem that the hardening speed of the mold is slow due to the increase of the bend amount, the handling property is deteriorated, and furthermore the blocking point of RCS is deteriorated because the fusion point of RCS is lowered. It is recognized.

Claims (11)

  In a resin composition for shell mold containing a phenol resin as a resin caking component, it is composed of one or two or more kinds of phosphoric acid ester compounds which do not contain a halogen bond in the molecule, and the P content is 14% or more And a resin composition for a shell mold, which further comprises non-halogenated phosphoric acid esters having a viscosity of 150 mPa · s / 25 ° C. or higher.   The resin composition for shell mold according to claim 1, wherein at least one kind of the phosphoric acid ester compound is an aliphatic condensed phosphoric acid ester.   The non-halogen based phosphate ester is composed of 80% by mass or more of aliphatic condensed phosphate ester and 20% by mass or less of aromatic phosphate ester and / or aromatic condensed phosphate ester. Or the resin composition for shell molds of Claim 2.   The non-halogenated phosphoric acid ester is contained in a ratio of 1 to 50 parts by mass with respect to 100 parts by mass of the phenol resin. The resin composition for shell molds as described in a term.   The resin composition for a shell mold according to any one of claims 1 to 4, wherein a novolak-type phenol resin and / or a resol-type phenol resin is used as the phenol resin.   As the phenol resin, a novolak type phenol resin and a resol type phenol resin are used in combination, and a use ratio of the novolac type phenol resin (A) to the resol type phenol resin (B) is mass ratio: A: B = It is 95: 5-5: 95, The resin composition for shell molds of Claim 5 characterized by the above-mentioned.   A resin composition for a shell mold according to any one of claims 1 to 6 is used as a caking agent, and the surface of the refractory aggregate is covered with a layer of the caking agent. Resin-coated sand featuring   The resin coated sand according to claim 7, wherein a lubricant is contained in the binder layer.   9. The resin coated sand according to claim 7, wherein a silane coupling agent is further contained in the binder layer.   A resin composition for a shell mold according to any one of claims 1 to 6 and a refractory aggregate are kneaded to form a coating layer comprising the resin composition on the surface of the refractory aggregate. A method of producing a resin coated sand characterized by forming.   A mold for shell mold, characterized in that the resin coated sand according to any one of claims 7 to 9 is molded and cured.