WO2017061598A1 - Binder composition for forming casting mold, sand composition for forming casting mold, and method for producing casting mold - Google Patents

Abstract

This binder composition for forming a casting mold contains furfuryl alcohol and a plant-derived phenol. A sand composition for forming a casting mold according to the present invention contains the binder composition for forming a casting mold, a refractory particulate material and a curing agent. A method for producing a casting mold according to the present invention comprises a step wherein a mold for forming a casting mold is filled with the sand composition for forming a casting mold and the binder composition for forming a casting mold contained in the sand composition for forming a casting mold is cured.

Description

Binder composition for mold making, sand composition for mold making, and method for producing mold

The present invention relates to a binder composition for mold making, a sand composition for mold making, and a method for producing a mold.
This application claims priority based on Japanese Patent Application No. 2015-201185 for which it applied to Japan on October 9, 2015, and uses the content here.

Conventionally, a self-hardening mold is known as one of casting molds. The self-hardening mold is a fire-resistant granular material such as silica sand, which is prepared by adding and kneading a binder mainly composed of an acid curable resin and a curing agent such as xylene sulfonic acid, and then kneading the obtained kneaded sand. It is manufactured by filling the mold and curing the binder.

The acid curable resin is a resin (furan resin) generally made of furfuryl alcohol, urea, phenol, formaldehyde or the like as a main raw material, and is polycondensed while being dehydrated with an acid and cured. Although a mold (furan mold) produced using such a furan resin has high strength, it has a drawback that the cured product is hard and is less sexual (see Non-Patent Document 1).
Here, the “nullness” is the performance that can cope with the shrinkage when the molten metal (molten metal) poured into the mold solidifies, that is, the flexibility of the mold that can be deformed as the molten metal shrinks.

When the molten metal poured into the mold is solidified, the contraction stress can be attenuated if the mold is more excellent in nature.
However, molds that are less prone are difficult to attenuate shrinkage stress and are prone to casting defects called hot cracks. In particular, when casting a cast steel (for example, a thin cast steel) having a large solidification shrinkage, a hot crack is likely to occur.

As a method for preventing hot cracking, a method using phosphoric acid as a curing agent for curing an acid curable resin has been proposed. When phosphoric acid is used as the curing agent, the mold strength at high temperatures is lower than when xylene sulfonic acid or the like is used. When the mold strength is lowered, the disintegration property due to thermal deterioration is increased, so that the contraction stress when the molten metal poured into the mold solidifies can be attenuated by the mold collapse.

However, in the method using phosphoric acid as a curing agent, the heat resistance of the mold is lowered. As a result, the frequency of inducing molten metal intrusion into the mold is increased, and new casting defects such as insertion defects (melt metal enters the mold) and sand biting (mold sand enters the casting) are induced. Therefore, improvement is required.

In recent years, a mold using an alkali phenol resin instead of a furan resin has been proposed. A mold using an alkali phenol resin is superior in flexibility (i.e., better) than a furan mold, and casting defects such as insertion defects and sand bites are less likely to occur.
However, a mold using an alkali phenol resin has a lower mold strength at room temperature and a lower sand regeneration rate than a furan mold. In addition, when using a mold using an alkali phenol resin and a furan mold in one factory, different types of resin are attached to the sand collected from each mold, so it can be recycled together. It can't be done and it takes time. In the case where both cast iron and cast steel are produced in one factory, it is usually reasonable to unify them into furan molds.
Therefore, there is a need for furan molds that are superior in nature.

The present invention has been made in view of the above circumstances, and is capable of producing a mold having superior properties while maintaining normal temperature strength, a mold forming binder composition, a mold forming sand composition, and a mold manufacturing method. The purpose is to provide.

The present invention has the following aspects.
[1] A binder composition for mold making containing furfuryl alcohol and plant-derived phenols.
[2] The binder composition for mold making according to [1], further containing a reaction product of urea and aldehydes.
[3] The plant-derived phenol is at least one selected from the group consisting of cashew nut shell liquid, cardanol, curdall, 2-methyl curdal and anacardic acid, according to [1] or [2] Binder composition for mold making.
[4] The mold forming binder composition according to [2], wherein the aldehyde is at least one selected from the group consisting of formaldehyde, glyoxal, and furfural.
[5] The composition according to any one of [1] to [4], wherein a content of the plant-derived phenol is 1 to 40% by mass in 100% by mass of the binder composition for mold making. Binder composition for mold making.
[6] A mold molding sand composition comprising the mold molding binder composition according to any one of [1] to [5], a refractory granular material, and a curing agent.
[7] Manufacture of a mold, wherein the mold molding sand composition according to [6] is filled in a mold for mold production, and the mold molding binder composition contained in the mold molding sand composition is cured. Method.

According to the present invention, it is possible to provide a mold-forming binder composition, a mold-forming sand composition, and a method for producing a mold, which can produce a mold having superior properties while maintaining normal temperature strength.

It is a schematic block diagram which shows the hot strain testing machine used for the evaluation of nature.

In the following description, the “mold” is formed by using a sand mold molding composition containing the binder composition for mold molding of the present invention.

"Binder composition for mold making"
The binder composition for mold making of the present invention (hereinafter, also simply referred to as “binder composition”) is used as a binder in producing a mold, and furfuryl alcohol, Contains plant-derived phenols. It is preferable that the binder composition further contains a reaction product of urea and aldehydes.

<Phenols derived from plants>
Plant-derived phenols include cashew nut shell liquid (CNSL), cardanol, curdall, 2-methyl curdal, anacardic acid, and the like. These may be used individually by 1 type and may be used in combination of 2 or more type. Examples of the CNSL preferably used in the present invention include industrial CNSL obtained by heating natural CNSL, distilled CNSL obtained by distilling and purifying natural CNSL, or industrial CNSL. Distilled and refined CNSL is particularly suitable as a phenol derived from plants because it contains fewer impurities and has a higher abundance ratio of cardanol and curdle than industrial CNSL obtained only by heating natural CNSL. Further, it is more preferable to use at least one kind of cardanol, curdle and 2-methyl curdle obtained by further purifying distilled purified CNSL and removing impurities as plant-derived phenols.

<Reaction product of urea and aldehydes>
When the binder composition further contains a reaction product of urea and aldehydes, the room temperature strength of the mold is further improved.
Examples of aldehydes include formaldehyde, glyoxal, and furfural. These may be used individually by 1 type and may be used in combination of 2 or more type. Among these, formaldehyde is preferable in that the curing of the binder composition proceeds sufficiently.

Examples of the reaction product of urea and aldehydes include methylolated urea which is an adduct of urea and aldehydes, and methyleneated urea which is a condensate of methylolated urea.
Here, an example of the adduct and the condensate will be described below by taking the case where the aldehyde is formaldehyde as an example.

When urea and formaldehyde are reacted in the presence of a basic catalyst, formaldehyde is added to urea as shown below, and methylolated urea having 1 to 3 methylol groups (—CH ₂ OH) in one molecule A mixture of

Although the ratio of each methylolated urea in the mixture varies depending on the ratio of urea and formaldehyde, it cannot be said unconditionally, but the main component is methylolated urea having one or two methylol groups in one molecule. is there. As the number of methylol groups in one molecule increases, the generation rate decreases due to steric hindrance.
Here, the main component means 50% by mass or more in 100% by mass of the mixture.
In the present invention, “in 100% by mass” means “relative to the total mass”. For example, “in 100% by mass of the mixture” means “relative to the total mass of the mixture”, that is, “when the total mass of the mixture is 100% by mass”.

When the reaction system is changed from basic to acidic in the state in which methylolated urea is generated, methylolated urea is condensed with each other as shown below to generate methyleneated urea.
In the following formula, in order to simplify the chemical formula, a portion other than the methylol group of methylolated urea is described as “R” or “R ′”.

The above reaction between urea and formaldehyde can be performed in furfuryl alcohol, which will be described in detail later.

<Optional component>
The binder composition may contain components (arbitrary components) other than the components described above.
Examples of optional components include condensates of furfuryl alcohol and aldehydes, silane coupling agents, formaldehyde reducing agents, and water.

The condensate of furfuryl alcohol and aldehydes can be obtained by reacting furfuryl alcohol and formaldehyde under acidic conditions. At this time, it is preferable to use 0.1 to 1 mol of aldehyde per 1 mol of furfuryl alcohol. If the amount of aldehyde used is 0.1 mol or more, it becomes a condensate with a low degree of polymerization, so that the pot life can be easily set. If it is 1 mol or less, the condensate has a high degree of polymerization, so the strength of the template. Will increase.
Examples of aldehydes include formaldehyde, glyoxal, and furfural. These may be used individually by 1 type and may be used in combination of 2 or more type.

If the binder composition contains a silane coupling agent, the strength of the mold is further improved.
Examples of the silane coupling agent include N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane.

The formaldehyde reducing agent is for reducing formaldehyde that is generated when molten metal is poured into a mold.
Examples of formaldehyde reducing agents include urea, resorcinol, pyrogallol and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

Water is water derived from condensed water generated when synthesizing reaction products of urea and aldehydes, water supplied by aqueous raw materials (for example, formalin, etc.), and all water added separately as necessary. Is included.

<Content>
The content of each component in 100% by mass of the binder composition is as follows.
When the binder composition does not contain a reaction product of urea and aldehydes, the content of furfuryl alcohol is preferably 60 to 99% by mass, and 65 to 95% by mass in 100% by mass of the binder composition. % Is more preferable, and 70 to 90% by mass is more preferable. If the content of furfuryl alcohol is 60% by mass or more, the pot life can be easily set. On the other hand, if the content of furfuryl alcohol is 99% by mass or less, the initial strength of the mold is further improved.

When the binder composition contains a reaction product of urea and aldehydes, the total content of furfuryl alcohol and the reaction product is 60 to 99% by mass in 100% by mass of the binder composition. % Is preferable, 65 to 95% by mass is more preferable, and 70 to 90% by mass is further preferable. When the total content of furfuryl alcohol and the reaction product is 60% by mass or more, the initial strength of the mold is further improved. On the other hand, if the total content of furfuryl alcohol and the reaction product is 99% by mass or less, the final strength of the mold is further improved.

The content of the reaction product of urea and aldehydes is preferably 2 to 50% by mass, more preferably 3 to 45% by mass, and further preferably 5 to 40% by mass in 100% by mass of the binder composition. preferable. When the content of the reaction product is 2% by mass or more, the initial strength of the mold is further improved. On the other hand, if the content of the reaction product is 50% by mass or less, the final strength of the mold is further improved.

The nitrogen atom content derived from urea or the like is preferably 0.1 to 6% by mass, more preferably 0.1 to 4.5% by mass in 100% by mass of the binder composition.
The nitrogen atom content affects the initial strength and final strength of the template. The initial strength of the template tends to increase as the nitrogen atom content decreases, and the final template strength increases as the nitrogen atom content increases. The strength tends to increase.
Therefore, it is preferable to appropriately adjust the nitrogen atom content as necessary. If the nitrogen atom content is within the above range, a template having an excellent balance between the initial strength and the final strength can be easily obtained.

The content of plant-derived phenols is preferably 1 to 40% by mass, more preferably 5 to 35% by mass, and still more preferably 10 to 30% by mass in 100% by mass of the binder composition. If the content of plant-derived phenols is within the above range, a template having better properties can be obtained. Moreover, the mold strength at high temperatures can be maintained well.

When the binder composition contains a reaction product of urea and aldehydes, the total content of furfuryl alcohol, plant-derived phenols and the reaction product is 100% by mass of the binder composition. Among them, 65 to 100% by mass is preferable, 80 to 99.5% by mass is more preferable, and 90 to 99.0% by mass is further preferable. When the total content of furfuryl alcohol, plant-derived phenols and the reaction product is 65% by mass or more, the initial strength of the mold is further improved. On the other hand, if the total content of furfuryl alcohol, plant-derived phenols, and the reaction product is 100% by mass or less, the properties of the template are further improved.

The content of the condensate of furfuryl alcohol and aldehydes is preferably 10 to 30% by mass and more preferably 15 to 25% by mass in 100% by mass of the binder composition. When the content of the condensate of furfuryl alcohol and aldehydes is 10% by mass or more, the initial strength of the mold is further improved. On the other hand, if the content of the condensate of furfuryl alcohol and aldehydes is 30% by mass or less, the final strength of the mold is further improved.

The content of the silane coupling agent is preferably 0.01 to 3% by mass and more preferably 0.1 to 1% by mass in 100% by mass of the binder composition. If the content of the silane coupling agent is 0.01% by mass or more, the strength of the mold is further improved, and if it is 3% by mass or less, a significant cost increase can be suppressed.

The content of the formaldehyde reducing agent is preferably 0.1 to 3% by mass, more preferably 0.5 to 1% by mass in 100% by mass of the binder composition. If the content of the formaldehyde reducing agent is 0.1% by mass or more, generation of formaldehyde during pouring can be sufficiently reduced, and if it is 3% by mass or less, a significant cost increase can be suppressed.

The content of water is preferably 1 to 25% by mass and more preferably 3 to 15% by mass in 100% by mass of the binder composition. If the water content is 1% by mass or more, the strength of the mold is further improved, and if it is 25% by mass or less, a significant cost increase can be suppressed.

<Method for producing binder composition>
The binder composition can be obtained, for example, by mixing furfuryl alcohol, plant-derived phenols, and optional components as necessary.
Plant-derived phenols that have been reacted with aldehydes in advance can also be used. However, in this case, the viscosity of the binder composition tends to increase due to the resinization of plant-derived phenols, and the binder composition and the refractory granular material described below are kneaded. May be difficult. Therefore, when the viscosity of the binder composition increases, it is preferable to adjust the viscosity by adding water or the like.

In addition, when the binder composition contains a reaction product of urea and aldehydes, for example, it can be obtained in a state in which the reaction product of urea and aldehydes is dissolved in furfuryl alcohol, as follows. This is preferable.
First, furfuryl alcohol, urea, and aldehydes are mixed, and an aqueous solution of a basic catalyst (for example, sodium hydroxide, potassium hydroxide, etc.) is added to adjust the pH of the mixture to 9-10. The mixture is heated to react urea with aldehydes (first addition reaction) to obtain, for example, the above-mentioned adduct of urea and aldehydes (methylolated urea). The molar ratio of urea to aldehydes (aldehydes / urea) is preferably 1.5 to 2.0.
Subsequently, an acidic catalyst (for example, hydrochloric acid, sulfuric acid, etc.) is added to the reaction solution, the pH of the reaction solution is adjusted to 2 to 4, and the condensation reaction of methylolated urea proceeds, for example, the condensation of methylolated urea described above. Product (methyleneated urea) is obtained.
Again, an aqueous solution of a basic catalyst (eg, sodium hydroxide, potassium hydroxide, etc.) is added to the reaction solution to adjust the pH of the reaction solution to 9-10, and urea is further added. In the first addition reaction, an excess of aldehydes is used with respect to urea, so that there are free aldehydes in the reaction solution. When the pH of the reaction solution is made alkaline again and urea is further added, the free aldehydes react with urea (second addition reaction), and the adduct of urea and aldehydes (methylolated urea) is produced. can get.

The reason for the addition reaction in two stages is as follows.
That is, if the proportion of the methyleneated urea in the furfuryl alcohol increases, it may precipitate. When methylolated urea and methyleneated urea are present in an appropriate ratio in furfuryl alcohol, the state in which methyleneated urea is dissolved in furfuryl alcohol can be maintained. Therefore, as described above, it is preferable to perform a second addition reaction after the condensation reaction to produce methylolated urea.
Most of the furfuryl alcohol exists in a free state in the reaction solution, but a part of the furfuryl alcohol may react with the aldehyde in the reaction of urea with the aldehyde.

Methylolated urea and methyleneated urea are obtained in a state dissolved in furfuryl alcohol. To this, plant-derived phenols and optional components as necessary are added to obtain a binder composition.
The reaction product of urea and aldehydes may be reacted with urea and aldehydes in the absence of furfuryl alcohol and then mixed with furfuryl alcohol or the like.

<Effect>
The binder composition of the present invention described above contains furfuryl alcohol and plant-derived phenols. Plant-derived phenols have a hydrocarbon group (long-chain hydrocarbon group) having 15 carbon atoms in the molecule. It is considered that this long-chain hydrocarbon group becomes a template for the following reasons and can impart more sex.
That is, when the binder composition is cured by the action of a curing agent in the production of a mold, a three-dimensional network crosslinked structure of furfuryl alcohol is formed, and this three-dimensional network crosslinked structure has a long-chain hydrocarbon group. Plant-derived phenols are taken up. As a result, it is possible to obtain a mold having superior properties while maintaining the normal temperature strength. In addition, since plant-derived phenols having a long-chain hydrocarbon group are incorporated into the three-dimensional network cross-linked structure, the heat resistance of the mold is improved, so that the mold strength at high temperatures can be maintained well.

By using the binder composition of the present invention, a mold having better properties can be obtained, so that the contraction stress when the molten metal poured into the mold solidifies can be attenuated without relying on the disintegration property of the mold. . Therefore, it is not necessary to increase the mold disintegration more than necessary, and it is not necessary to reduce the mold strength at high temperatures.
Moreover, since the casting_mold | template excellent in heat resistance is obtained if the binder composition of this invention is used, casting defects, such as an insertion defect and sand biting, can also be suppressed.

One aspect of the present invention is a binder composition for mold making that contains furfuryl alcohol and plant-derived phenols and does not contain a reaction product of urea and aldehydes.
Another aspect of the present invention contains furfuryl alcohol and plant-derived phenols, does not contain a reaction product of urea and aldehydes, and in 100% by mass of the binder composition for mold making, A mold forming binder composition having a furfuryl alcohol content of 60 to 99% by mass and a plant-derived phenol content of 1 to 40% by mass.
Another aspect of the present invention is a mold-forming binder composition containing furfuryl alcohol, plant-derived phenols, and a silane coupling agent, not containing a reaction product of urea and aldehydes. In 100% by mass of the product, the content of furfuryl alcohol is 60 to 99% by mass, the content of plant-derived phenols is 1 to 40% by mass, and the content of the silane coupling agent is 0.01 to It is a binder composition for mold making which is 3 mass% (however, the total content of furfuryl alcohol, plant-derived phenols, and silane coupling agent does not exceed 100 mass%).
Another aspect of the present invention is that it contains furfuryl alcohol, plant-derived phenols, a silane coupling agent, and water, does not contain a reaction product of urea and aldehydes, and is used for mold making. In 100% by mass of the binder composition, the content of furfuryl alcohol is 60 to 99% by mass, the content of plant-derived phenols is 1 to 40% by mass, and the content of the silane coupling agent is 0. 0.01 to 3% by mass and water content is 1 to 25% by mass (however, the total content of furfuryl alcohol, plant-derived phenols, silane coupling agent, and water is 100% by mass) Is a binder composition for mold making.
Another aspect of the present invention contains furfuryl alcohol, plant-derived phenols, a silane coupling agent, water, a condensate of furfuryl alcohol and aldehydes, and urea and aldehydes. The reaction product is not contained, and the content of furfuryl alcohol is 60 to 99% by mass and the content of plant-derived phenols is 1 to 40% by mass in 100% by mass of the binder composition for mold making. The content of the silane coupling agent is 0.01 to 3% by mass, the content of water is 1 to 25% by mass, and the content of the condensate is 10 to 30% by mass (however, The total amount of furyl alcohol, plant-derived phenols, silane coupling agent, water, and the content of the condensate does not exceed 100% by mass).
Another aspect of the present invention contains furfuryl alcohol, plant-derived phenols, a silane coupling agent, water, a condensate of furfuryl alcohol and aldehydes, and a formaldehyde reducing agent, and urea. The content of furfuryl alcohol is 60 to 99% by mass in 100% by mass of the binder composition for mold making, and the content of plant-derived phenols is not contained. 1 to 40% by mass, the content of the silane coupling agent is 0.01 to 3% by mass, the content of water is 1 to 25% by mass, and the content of the condensate is 10 to 30% by mass. The content of the formaldehyde reducing agent is 0.1 to 3% by mass (provided that furfuryl alcohol, plant-derived phenols, silane coupling agent, water, the condensate, and formaldehyde Total content of dehydroaripiprazole reducing agent is binder composition for mold formation which is not exceeding) 100 mass%.

One aspect of the present invention is a binder composition for mold making containing furfuryl alcohol, plant-derived phenols, and a reaction product of urea and aldehydes.
Another aspect of the present invention includes furfuryl alcohol, a phenol derived from a plant, a reaction product of urea and aldehydes, and 100% by mass of a binder composition for mold making, furfuryl alcohol. And the reaction product in a total amount of 60 to 99% by mass, and the content of plant-derived phenols is 1 to 40% by mass.
Another aspect of the present invention includes furfuryl alcohol, a phenol derived from a plant, a reaction product of urea and aldehydes, and 100% by mass of a binder composition for mold making, furfuryl alcohol. And the reaction product content is 60 to 99% by mass, the content of plant-derived phenols is 1 to 40% by mass, and the content of the reaction product is 2 to 50% by mass. It is a binder composition for mold making.
Another aspect of the present invention includes furfuryl alcohol, a phenol derived from a plant, a reaction product of urea and aldehydes, and 100% by mass of a binder composition for mold making, furfuryl alcohol. And the reaction product content is 60 to 99% by mass, the content of plant-derived phenols is 1 to 40% by mass, and the content of the reaction product is 2 to 50% by mass. And a mold forming binder composition having a nitrogen atom content of 0.1 to 6% by mass.
Another aspect of the present invention is a mold-forming binder composition 100 mass containing furfuryl alcohol, plant-derived phenols, a reaction product of urea and aldehydes, and a silane coupling agent. %, The total content of furfuryl alcohol and the reaction product is 60 to 99% by mass, the content of plant-derived phenols is 1 to 40% by mass, and the content of the reaction product Is 2 to 50% by mass, the nitrogen atom content is 0.1 to 6% by mass, and the content of the silane coupling agent is 0.01 to 3% by mass (but furfuryl alcohol and plant-derived) The total amount of phenols, the reaction product, and the silane coupling agent does not exceed 100% by mass).
Another aspect of the present invention is a binder composition for mold making, comprising furfuryl alcohol, plant-derived phenols, a reaction product of urea and aldehydes, a silane coupling agent, and water. The total content of furfuryl alcohol and the reaction product in 100% by mass of the product is 60 to 99% by mass, the content of plant-derived phenols is 1 to 40% by mass, and the reaction product The content of is 2 to 50% by mass, the nitrogen atom content is 0.1 to 6% by mass, the content of the silane coupling agent is 0.01 to 3% by mass, and the content of water is Mold making of 1 to 25% by mass (however, the total content of furfuryl alcohol, plant-derived phenols, the reaction product, silane coupling agent, and water does not exceed 100% by mass) It is a binder composition for use.
Another aspect of the present invention is a condensate of furfuryl alcohol, plant-derived phenols, reaction product of urea and aldehydes, silane coupling agent, water, furfuryl alcohol and aldehydes. The total content of furfuryl alcohol and the reaction product in 60% by mass of the binder composition for mold making is 60 to 99% by mass, and the content of plant-derived phenols is 1 to 40% by mass, the reaction product content is 2 to 50% by mass, the nitrogen atom content is 0.1 to 6% by mass, and the silane coupling agent content is 0.01%. 3% by mass, water content 1-25% by mass, condensate content 10-30% by mass (however, furfuryl alcohol, plant-derived phenols, and reaction product) And silane coupling And grayed agent, water and a total binder composition for mold formation which is not exceeding) 100 mass% of the content of the condensate.
Another aspect of the present invention is a condensate of furfuryl alcohol, plant-derived phenols, reaction product of urea and aldehydes, silane coupling agent, water, furfuryl alcohol and aldehydes. And 100% by mass of the binder composition for mold making, the total content of furfuryl alcohol and the reaction product is 60 to 99% by mass, and the plant-derived phenol The content of the reaction product is 1 to 40% by mass, the content of the reaction product is 2 to 50% by mass, the nitrogen atom content is 0.1 to 6% by mass, and the content of the silane coupling agent The amount is 0.01 to 3% by mass, the content of water is 1 to 25% by mass, the content of the condensate is 10 to 30% by mass, and the content of the formaldehyde reducing agent is 0.1%. ~ 3% by mass (however, The total content of rufuryl alcohol, plant-derived phenols, the reaction product, the silane coupling agent, water, the condensate, and the formaldehyde reducing agent does not exceed 100% by mass). It is a certain binder composition for mold making.

"Sand composition for mold making"
The mold molding sand composition of the present invention (hereinafter also simply referred to as “sand composition”) contains the above-described binder composition of the present invention, a refractory granular material, and a curing agent.

<Fireproof granular material>
As the refractory granular material, conventionally known materials such as silica sand, chromite sand, zircon sand, olivine sand, alumina sand, mullite sand, and synthetic mullite sand can be used. Moreover, the thing which collect | recovered used refractory granular materials (collected sand), the thing which regenerated (regenerated sand), etc. can be used. These may be used individually by 1 type and may be used in combination of 2 or more type. In particular, chromite sand, zircon sand, and alumina sand are preferred for portions that require fire resistance.

<Curing agent>
As the curing agent, conventionally known ones such as sulfonic acid compounds such as xylene sulfonic acid, phosphoric acid compounds, and sulfuric acid can be used. These may be used individually by 1 type and may be used in combination of 2 or more type. Among these, a sulfonic acid compound is preferable in that the normal temperature strength and heat resistance of the template are further increased.

<Content>
The mixing ratio of the refractory granular material, the binder composition and the curing agent in the sand composition can be set as appropriate, but the binder composition is 0.3 to 2 parts by mass with respect to 100 parts by mass of the refractory granular material. The amount is preferably 0.5 to 1.5 parts by mass. Further, the curing agent is preferably 0.045 to 1.2 parts by mass, and more preferably 0.075 to 0.9 parts by mass with respect to 100 parts by mass of the refractory granular material. With such a mixing ratio, it is easy to obtain a mold having sufficient strength.

The content of plant-derived phenols in 100% by mass of the sand composition is preferably 0.003 to 0.8% by mass, and more preferably 0.005 to 0.6% by mass. . When the content of plant-derived phenols in the sand composition is within the above range, a mold having higher properties and heat resistance can be obtained.

<The manufacturing method of a sand composition>
A sand composition is obtained by mixing a binder composition, a refractory granular material, and a curing agent.
The mixing method is not particularly limited as long as it is a general mixing method, and examples thereof include a method using a stirrer.

<Effect>
Since the sand composition of the present invention described above contains the above-described binder composition of the present invention, a mold having superior properties can be obtained while maintaining normal temperature strength.
Moreover, since the casting | molding excellent in heat resistance is obtained if the sand composition of this invention is used, casting defects, such as an insertion defect and sand biting, can also be suppressed.

One aspect of the present invention includes a binder for mold making, a refractory granular material, and a curing agent, and a binder composition for mold making with respect to 100 parts by weight of the refractory granular material. The sand composition for mold making has a product content of 0.3 to 2 parts by mass and a hardener content of 0.045 to 1.2 parts by mass.
Another aspect of the present invention includes the above-mentioned binder for mold making, a refractory granular material, and a curing agent, and a binder composition for mold making with respect to 100 parts by mass of the refractory granular material. The content of the product is 0.3 to 2 parts by mass, the content of the curing agent is 0.045 to 1.2 parts by mass, and 100% by mass of the mold molding sand composition contains plant-derived phenols. A sand composition for mold making having a content of 0.003 to 0.8% by mass.

"Mold manufacturing method"
As a method for producing a mold from the sand composition of the present invention, a self-hardening mold making method can be employed. That is, when the sand composition of the present invention is filled in a predetermined mold for mold making, the binder composition in the sand composition is cured by the action of the curing agent. As a result, a template can be obtained.
The method for producing a mold of the present invention includes a step of filling a mold for producing a mold with the sand composition of the present invention and curing the binder composition contained in the sand composition.

The mold obtained by the present invention is superior in quality while maintaining the normal temperature strength. Moreover, since the mold obtained by the present invention is also excellent in heat resistance, casting defects such as insertion defects and sand biting can be suppressed.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The physical properties of the test pieces (molds) obtained in the examples and comparative examples were measured by the following methods.

(Measurement of water content)
The water content of the acid curable resin was determined by the moisture test method for chemical products of JIS K 0068.

(Measurement of nitrogen atom content)
The nitrogen atom content was determined by the titration method of the factory wastewater test method of JIS K 0102.

(Measurement of compressive strength)
The compressive strength (mold strength) of the test pieces obtained in each Example and Comparative Example is obtained by using a tabletop pressure tester (manufactured by Takachiho Machinery Co., Ltd.) according to the testing method for foundry sand of JIS Z 2601. It was measured.

(Measurement of bulk density)
The bulk density of the test pieces obtained in each Example and Comparative Example was determined by the following general formula (I). METLER PM 4000 (manufactured by Nippon Shibel Hegner Co., Ltd.) was used as the electronic balance used for mass measurement.
In addition, the bulk density is measured in order to confirm that the sand composition having substantially the same mass is filled in the wooden mold.
Test piece bulk density (g / cm ³ ) = Test piece mass (g) / Test piece volume (cm ³ ) (I)

(Evaluation of gender more)
The test piece obtained in each of the examples and comparative examples was evaluated according to “Mold Production Technology” (Foundation Materials Center, January 20, 1995, p411 to 412). Based on the “hot strain test”, evaluation was performed as follows using the hot strain tester 10 shown in FIG.
The size of the test piece was 25.4 mm × 6.35 mm × 114.3 mm.
As shown in FIG. 1, one end in the longitudinal direction of the test piece 12 was clamped and fixed by the clamp 11, and a 30 g weight 13 was placed on the upper surface of the other end side of the test piece 12.
Next, the central portion of the lower surface of the test piece 12 was heated to 800 ° C. with the electric heater 14. When the test piece 12 is heated, the test piece 12 bends upward due to thermal expansion, but thereafter, the upward bending is stopped by the weight 13 and begins to bend downward, eventually breaking.
The displacement of the test piece 12 after 3 minutes from the start of heating was measured with a laser displacement meter 15. It means that the larger the displacement, the better the nature.

"Example 1"
<Preparation of binder composition>
In a four-necked flask equipped with a thermometer, a condenser, and a stirrer, 827.1 parts by mass of furfuryl alcohol, 24.18 parts by mass of urea, 33.9 parts by mass of paraformaldehyde 92% by mass, and 15% by mass water An aqueous sodium oxide solution (2.0 parts by mass) was added and reacted at 80 ° C. for 1 hour (first addition reaction). Thereafter, 10 parts by mass of hydrochloric acid (3.0 parts by mass) was added, and the mixture was further reacted for 3 hours (condensation reaction). Thereafter, 2.0 parts by mass of a 15% by mass aqueous sodium hydroxide solution and 14.82 parts by mass of urea were added and further reacted for 30 minutes (second addition reaction) to obtain a reaction mixture. To the obtained reaction mixture, commercially available distilled purified CNSL (trade name “LB-7000”, manufactured by Tohoku Chemical Co., Ltd., nonvolatile content of 99.5% by mass at 125 ° C., monomer ratio in the nonvolatile content of 100% by mass ( Cardanol ratio 90% by mass, curdle ratio 10% by mass))) 101 parts by mass and silane coupling agent (N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane) 2 parts by mass, The binder composition 1010 parts by mass was obtained.
The content of furfuryl alcohol in 100% by mass of the obtained binder composition is 81.9% by mass, the content of the reaction product of urea and paraformaldehyde is 6.9% by mass, The content of distilled and purified CNSL was 10.0% by mass, the content of the silane coupling agent was 0.2% by mass, and the content of water was 1.0% by mass. The nitrogen atom content in 100% by mass of the binder composition was 1.8% by mass.

<Manufacture of sand composition>
100 parts by weight of silica sand (manufactured by Mitsubishi Corporation Building Materials Co., Ltd., free mantle new sand) contains 1 part by weight of the previously obtained binder composition and a curing agent (35% by weight of xylenesulfonic acid and 6% by weight of sulfuric acid) 0.4 mass part) was added and kneaded with a Shinagawa universal stirrer (manufactured by Shinagawa Kogyo Co., Ltd., MIXER) to obtain a sand composition.

<Manufacture of test pieces 1>
A portion of the obtained sand composition is immediately filled into a test piece preparation wooden mold in which a cylindrical mold having an inner diameter of 50 mm and a height of 50 mm is formed under conditions of a temperature of 25 ° C. and a humidity of 40%, and is cured. The test piece was taken out after 1 hour from the start of curing (molding time 1 hour).
About the obtained test piece, the compressive strength and bulk density after 1 hour, 3 hours, and 24 hours passed from the start of hardening were measured. The results are shown in Table 1.

<Manufacture of test pieces 2>
A test in which a part of the obtained sand composition was immediately formed into a rectangular parallelepiped mold having a longitudinal inner diameter of 25.4 mm, a lateral inner diameter of 6.35 mm, and a height of 114.3 mm under the conditions of a temperature of 25 ° C. and a humidity of 40%. The mold for making the piece was filled and cured, and the test piece was taken out after the lapse of 24 hours from the start of curing (24 hours of mold removal time).
About the obtained test piece, the nature was evaluated more or less. The results are shown in Table 1.

"Example 2"
A binder composition was prepared in the same manner as in Example 1 except that the amount of furfuryl alcohol was changed to 726.1 parts by mass and the amount of distilled and purified CNSL was changed to 202 parts by mass. A sand composition and a test piece were produced using the binder composition, and various measurements were performed. The results are shown in Table 1.
The content of furfuryl alcohol in 100% by mass of the obtained binder composition is 71.9% by mass, and the content of the reaction product of urea and paraformaldehyde is 6.9% by mass. Yes, the content of distilled and purified CNSL was 20.0% by mass, the content of the silane coupling agent was 0.2% by mass, and the content of water was 1.0% by mass. The nitrogen atom content in 100% by mass of the binder composition was 1.8% by mass.

"Example 3"
A binder composition was prepared in the same manner as in Example 1 except that the amount of furfuryl alcohol was changed to 625.1 parts by mass and the amount of distilled and purified CNSL was changed to 303 parts by mass. A sand composition and a test piece were produced using the binder composition, and various measurements were performed. The results are shown in Table 1.
The content of furfuryl alcohol in the obtained binder composition 100% by mass is 61.9% by mass, and the content of the reaction product of urea and paraformaldehyde is 6.9% by mass. Yes, the content of distilled and purified CNSL was 30.0% by mass, the content of the silane coupling agent was 0.2% by mass, and the content of water was 1.0% by mass. The nitrogen atom content in 100% by mass of the binder composition was 1.8% by mass.

Example 4
The amount of furfuryl alcohol was changed to 625.1 parts by mass, and instead of distillation-purified CNSL, industrial CNSL (made by Tohoku Chemical Co., Ltd., trade name “CNSL (industrial)”, nonvolatile content at 125 ° C. 99.0 The binder was the same as in Example 1 except that 303 parts by mass of the monomer and 80% by mass of the monomer in the nonvolatile content (cardanol ratio 82% by mass, curdle ratio 18% by mass with respect to the whole monomer) were used. A composition was prepared, a sand composition and a test piece were produced using the obtained binder composition, and various measurements were performed, and the results are shown in Table 1.
The content of furfuryl alcohol in the obtained binder composition 100% by mass is 61.9% by mass, and the content of the reaction product of urea and paraformaldehyde is 6.9% by mass. Yes, the content of industrial CNSL was 30.0% by mass, the content of silane coupling agent was 0.2% by mass, and the content of water was 1.0% by mass. The nitrogen atom content in 100% by mass of the binder composition was 1.8% by mass.

"Comparative Example 1"
A binder composition was prepared in the same manner as in Example 1 except that the amount of furfuryl alcohol was changed to 928.1 parts by mass and distilled purified CNSL was not used. A sand composition and a test piece were produced using this, and various measurements were performed. The results are shown in Table 1.
In addition, content of furfuryl alcohol in 100 mass% of obtained binder compositions is 91.9 mass%, and content of the reaction product of urea and paraformaldehyde is 6.9 mass%. Yes, the content of the silane coupling agent was 0.2% by mass, and the content of water was 1.0% by mass. The nitrogen atom content in 100% by mass of the binder composition was 1.8% by mass.

"Comparative Example 2"
A binder composition was prepared in the same manner as in Example 1 except that the amount of furfuryl alcohol was changed to 928.1 parts by mass and no distillation-purified CNSL was used. In 100% by mass of the obtained binder composition, the content of furfuryl alcohol is 91.9% by mass, the content of the reaction product of urea and paraformaldehyde is 6.9% by mass, The content of the silane coupling agent was 0.2% by mass, and the content of water was 1.0% by mass. The nitrogen atom content in 100% by mass of the binder composition was 1.8% by mass.
Except for using the obtained binder composition and using 0.4 parts by weight of a 56% strength aqueous solution containing 51% by weight phosphoric acid and 5% by weight sulfuric acid as a curing agent, the same as in Example 1. A sand composition and a test piece were manufactured, and various measurements were performed. The results are shown in Table 1.

“Comparative Example 3”
In a four-necked flask equipped with a thermometer, a condenser, and a stirrer, 235.3 parts by mass of phenol, 106.2 parts by mass of 48% by mass aqueous sodium hydroxide, and 87.5 parts by mass of 48% by mass aqueous potassium hydroxide And 242.9 parts by mass of water were added, 300 parts by mass of 50% by mass formalin was added dropwise over about 1 hour and reacted at an internal temperature of 90 ° C. for 3 hours, and then a silane coupling agent (N— 10 parts by mass of β (aminoethyl) γ-aminopropylmethyldimethoxysilane) was added to obtain 981.9 parts by mass of an alkali phenol resin.
Add 100 parts by mass of silica sand (Mitsubishi Corporation Building Materials Co., Ltd., Freemantle Shinsuna), 1.5 parts by mass of the previously obtained alkali phenol resin and 0.3 parts by mass of a curing agent (triethylene glycol diacetate) The mixture was kneaded with a Shinagawa universal agitator (manufactured by Shinagawa Kogyo Co., Ltd., MIXER) to obtain a sand composition.
A test piece was produced in the same manner as in Example 1 except that the obtained sand composition was used, and various measurements were performed. The results are shown in Table 1.

From the results shown in Table 1, the test pieces obtained in Examples 1 to 4 had high room temperature strength. In addition, the test pieces obtained in Examples 1 to 4 could be displaced without cracking even when heated, and were more excellent in properties. From these results, the mold obtained using the binder composition of the present invention is easy to handle at room temperature and effective in preventing hot cracks during pouring, sand biting defects and insertion defects. It was confirmed that this was an excellent mold.
On the other hand, although the test piece obtained in Comparative Example 1 had a high normal temperature strength, the amount of displacement when heated was small, and the properties were inferior. Such a lower-quality mold causes a hot crack during pouring.
The test piece obtained in Comparative Example 2 had lower room temperature strength than the test pieces obtained in Examples 1 to 4. In addition, since the test piece was broken during the test in the evaluation of the nature, the test piece obtained in Comparative Example 2 is considered to be less prone to hot cracking, but it is inferior in heat resistance. It is thought that it becomes a factor which induces a sand biting defect and insertion defect at the time of hot water.
The test piece obtained in Comparative Example 3 using an alkali phenol resin as a binder was displaced without cracking the mold at a high temperature, and the test piece obtained in each example had the same degree of properties as the test piece. Had. However, the room temperature strength was particularly low.

"Example 5"
898 parts by mass of furfuryl alcohol, 100 parts by mass of distilled and purified CNSL, and 2 parts by mass of a silane coupling agent (N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane) are mixed to obtain 1000 parts by mass of a binder composition. Got a part. The content of furfuryl alcohol in the obtained binder composition 100% by mass is 89.8% by mass, the content of distilled purified CNSL is 10.0% by mass, and the content of the silane coupling agent The amount was 0.2% by mass.
Except having used the obtained binder composition, the sand composition and the test piece were manufactured similarly to Example 1, and various measurements were performed. The results are shown in Table 2.

"Example 6"
798 parts by mass of furfuryl alcohol, 200 parts by mass of distilled purified CNSL, and 2 parts by mass of a silane coupling agent (N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane) are mixed, and a binder composition of 1000 parts by mass is mixed. Got a part. In 100 mass% of the obtained binder composition, the content of furfuryl alcohol is 79.8 mass%, the content of distilled purified CNSL is 20.0 mass%, and the content of the silane coupling agent The amount was 0.2% by mass.
Except having used the obtained binder composition, the sand composition and the test piece were manufactured similarly to Example 1, and various measurements were performed. The results are shown in Table 2.

"Example 7"
698 parts by weight of furfuryl alcohol, 300 parts by weight of distilled and purified CNSL, and 2 parts by weight of a silane coupling agent (N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane) are mixed, and the binder composition is 1000 parts by weight. Got a part. The content of furfuryl alcohol in the obtained binder composition 100% by mass is 69.8% by mass, the content of distilled purified CNSL is 30.0% by mass, and the content of the silane coupling agent The amount was 0.2% by mass.
Except having used the obtained binder composition, the sand composition and the test piece were manufactured similarly to Example 1, and various measurements were performed. The results are shown in Table 2.

“Comparative Example 4”
998 parts by mass of furfuryl alcohol and 2 parts by mass of a silane coupling agent (N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane) were mixed to obtain 1000 parts by mass of a binder composition. The content of furfuryl alcohol in 100% by mass of the obtained binder composition was 99.8% by mass, and the content of the silane coupling agent was 0.2% by mass.
Except having used the obtained binder composition, the sand composition and the test piece were manufactured similarly to Example 1, and various measurements were performed. The results are shown in Table 2.

From the results shown in Table 2, the test pieces obtained in Examples 5 to 7 and the test piece obtained in Comparative Example 4 had the same room temperature strength.
However, the test pieces obtained in Examples 5 to 7 could be displaced without cracking even when heated, and were superior in quality. However, the test piece obtained in Comparative Example 4 had a displacement amount when heated. Was smaller and was inferior in nature.
From these results, the mold obtained using the binder composition of the present invention is easy to handle at room temperature and effective in preventing hot cracks during pouring, sand biting defects and insertion defects. It was confirmed that this was an excellent mold.
On the other hand, as in Comparative Example 4, a mold having a lower property becomes a factor that induces a hot crack during pouring.

If the binder composition for mold making of the present invention is used, it is possible to produce a mold having superior properties while maintaining normal temperature strength.

10 Hot strain tester 11 Clamp 12 Test piece 13 Weight 14 Electric heater 15 Laser displacement meter

Claims (7)

1. A binder composition for mold making containing furfuryl alcohol and plant-derived phenols.
2. The binder composition for mold making according to claim 1, further comprising a reaction product of urea and aldehydes.
3. The caking for mold making according to claim 1 or 2, wherein the plant-derived phenol is at least one selected from the group consisting of cashew nut shell liquid, cardanol, curdle, 2-methyl curdal and anacardic acid. Agent composition.
4. 3. The binder composition for mold making according to claim 2, wherein the aldehyde is at least one selected from the group consisting of formaldehyde, glyoxal and furfural.
5. The caking for mold making according to any one of claims 1 to 4, wherein a content of the plant-derived phenols is 1 to 40% by mass in 100% by mass of the binder composition for mold making. Agent composition.
6. A sand composition for mold making, comprising the binder composition for mold making according to any one of claims 1 to 5, a refractory granular material, and a curing agent.
7. A method for producing a mold, wherein the mold making sand composition according to claim 6 is filled in a mold for producing a mold, and the mold forming binder composition contained in the mold making sand composition is cured.

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