Cardanol-modified furan resin for casting, cardanol derivatives and preparation methods thereof

Abstract

The present application belongs to a method for preparing a furan resin. When using cardanol as a raw material of furan resin, conventional cardanol is used, which will cause the technical problem that the strength of the synthesized furan resin decreases after curing. A kind of cardanol modified furan resin for casting, cardanol derivatives and preparation methods thereof are provided. Cardanol is modified using thioglycolic acid, and a click chemistry reaction of a thiol-double bond occurs to obtain a cardanol derivative, and then a phenolic mixture and an aldehyde compound are reacted to obtain a cardanol modified furan resin, by partially modifying the unsaturated double bond of cardanol, a polar hydrophilic motif is introduced, and intermolecular forces are increased, thereby improving the strength of the furan resin. At the same time, the stratification phenomenon during storage and use is suppressed, and storage stability is improved. Then, a cardanol modified furan resin with more excellent performance is obtained, which has a good application prospect.

Description

Technical Field

[0001] The present application relates to a method for preparing a furan resin, and specifically to a cardanol-modified furan resin for casting, a cardanol derivative and a preparation method thereof. Background Art

[0002] Furan resin is a thermosetting resin with furfuryl alcohol as the main raw material, which is widely used in the field of foundry binders. However, as the main raw materials for its preparation, furfuryl alcohol, phenol and other reagents are relatively expensive, and phenol will pollute the environment and endanger human health. Therefore, the development of green and environmentally friendly furan resin is very important.

[0003] Cardanol is a natural phenolic compound extracted from cashew nut shell oil. It has the advantages of being green, environmentally friendly, low-priced, high temperature resistant and having strong interaction with the contact surface. The unsaturated carbon chain of C15 on its meta-substituent can improve the toughness of furan resin, and is a very excellent substitute for furfuryl alcohol and phenol. The degree of unsaturation of the common meta-side chain of cardanol is 0-3, and the components are saturated, monoene, diene and triene structures. However, the lipophilicity of the unsaturated carbon chain of the side group is too strong, which will cause the synthesized furan resin to be easily delaminated during storage and use, resulting in a decrease in the strength after curing, limiting its widespread use. Summary of the invention

[0004] The present application aims to solve the technical problem that when using conventional cardanol as a raw material for furan resin, the strength of the synthesized furan resin will decrease after curing. The present application provides a cardanol-modified furan resin for casting, a cardanol derivative and a preparation method thereof.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a method for preparing a cardanol-modified furan resin for casting, comprising:

[0007] Cardanol is modified by using thioglycolic acid to undergo a thiol-double bond click chemistry reaction to obtain a cardanol derivative;

[0008] A phenolic mixture and an aldehyde compound are reacted to obtain a cardanol-modified furan resin; the phenolic mixture comprises the cardanol derivative and a phenolic compound.

[0009] Further, the step of reacting the phenolic mixture with the aldehyde compound comprises:

[0010] The phenol mixture and the aldehyde compound are reacted under a base catalysis condition, and after the reaction is completed, the solvent is rotary evaporated to obtain the cardanol-modified furan resin.

[0011] Furthermore, the structure of the cardanol derivative is:

[0012]

[0013] Further, the phenolic compound is cardanol;

[0014] Place cardanol, cardanol derivatives and base catalyst in a reaction kettle and heat to 60-120° C.;

[0015] Add aldehyde compound dropwise and continue the reaction for 1 to 2 hours;

[0016] Add furfuryl alcohol and continue the reaction for 1 to 2 hours;

[0017] The product was dehydrated in vacuo to obtain cardanol-modified furan resin.

[0018] Furthermore, in the phenol mixture, the molar ratio of cardanol to the cardanol derivative is 1:(0.5-1.5).

[0019] Furthermore, the mass ratio of the cardanol, the cardanol derivative, the aldehyde compound, the base catalyst and the furfuryl alcohol is 50:(25-75):(150-180):(6-9):(20-75).

[0020] Furthermore, the modification of cardanol using thioglycolic acid comprises:

[0021] Dissolve cardanol and thioglycolic acid in dichloromethane, add azobisisobutyronitrile as an initiator, and reflux at 70°C for 6 to 8 hours under stirring;

[0022] After cooling, add water, extract and wash, and collect the dichloromethane layer;

[0023] The collected dichloromethane layer is subjected to rotary evaporation, and after drying, a powder is obtained, which is a cardanol derivative.

[0024] In a second aspect, the present application proposes a cardanol-modified furan resin for casting, which is obtained by the preparation method of the cardanol-modified furan resin for casting.

[0025] In a third aspect, the present application proposes a cardanol derivative, the structure of which is:

[0026]

[0027] In a fourth aspect, the present application proposes a method for preparing the above-mentioned cardanol derivative, comprising:

[0028] Dissolve cardanol and thioglycolic acid in dichloromethane, add azobisisobutyronitrile as an initiator, and reflux at 70°C for 6 hours under stirring;

[0029] After cooling, add water, extract and wash, and collect the dichloromethane layer;

[0030] The collected dichloromethane layer is subjected to rotary evaporation, and after drying, a powder is obtained, which is a cardanol derivative.

[0031] Compared with the prior art, this application has the following beneficial effects:

[0032] The present application proposes a method for preparing a furan resin modified by cardanol for casting, wherein cardanol is modified by thioglycolic acid, a thiol-double bond click chemistry reaction occurs, a cardanol derivative is obtained, and then a phenolic mixture and an aldehyde compound are reacted to obtain a cardanol-modified furan resin. The traditional furan resin prepared based on cardanol, due to the presence of an unsaturated carbon chain of C15 in the middle position of cardanol, improves the toughness of the resin on the one hand, and also reduces the storage stability of the furan resin on the other hand, making it easy to delaminate and reducing the mechanical properties. By partially modifying the unsaturated double bonds of cardanol and introducing polar hydrophilic moieties, the intermolecular forces are increased, thereby improving the strength of the furan resin, and at the same time, the delamination phenomenon during storage and use is suppressed, and the storage stability is improved. Thus, a cardanol-modified furan resin with better performance is obtained, which has good application prospects.

[0033] The present application also proposes a cardanol-modified furan resin for casting obtained by the preparation method of the cardanol-modified furan resin for casting, which has high strength, will not delaminate during storage and use, and has higher stability.

[0034] The present application also proposes a cardanol derivative and a preparation method thereof. Compared with traditional cardanol, the unsaturated double bonds of cardanol are modified, polar hydrophilic moieties are introduced, and the intermolecular forces are increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 This is a schematic diagram of the reaction principle of the cardanol derivatives proposed in this application. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0040] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invented product is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0041] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0042] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] Traditional furan resins prepared based on cardanol have a significant effect on the toughness and storage stability of the resin due to the presence of a C15 unsaturated carbon chain in the middle position of cardanol. This special carbon chain structure gives furan resin excellent toughness, making it perform well in some applications that require high toughness. However, at the same time, this unsaturated carbon chain also causes the furan resin to have a decreased stability during storage, prone to stratification, and decreased mechanical properties.

[0044] Therefore, in order to meet higher usage requirements, it is necessary to modify cardanol and appropriately increase its polarity and water solubility to ensure the mechanical properties of the resin binder for casting. The cardanol-modified furan resin proposed in this application will be able to effectively enhance its application potential in the field of sand casting.

[0045] Based on the above situation, the present application proposes a cardanol-modified furan resin for casting, a cardanol derivative and a preparation method thereof. The present application is further described in detail below in conjunction with examples and drawings.

[0046] The present application proposes a method for preparing a cardanol-modified furan resin for casting, comprising:

[0047] S1, using thioglycolic acid to modify cardanol, causing a thiol-double bond click chemistry reaction to obtain a cardanol derivative;

[0048] S2, reacting a phenol mixture with an aldehyde compound to obtain a cardanol-modified furan resin; the phenol mixture comprises the cardanol derivative and a phenol compound.

[0049] This application starts from the synthesis of cardanol derivatives, improves the furan resin raw materials, prepares cardanol-modified furan resin, and increases the intermolecular force in the resin and the compatibility of the system by introducing polar units. In practical applications, in addition to improving the curing speed and strength of the furan resin, it can also improve storage stability and cleanliness, and has excellent application prospects.

[0050] Example 1

[0051] 1) Synthesis of cardanol derivatives

[0052] Dissolve cardanol (3.02 g), thioglycolic acid (0.92 g), and azobisisobutyronitrile (140 mg) in 20 mL of dichloromethane and react at 70°C for 6 h under stirring. After the system is cooled, water is added to the reaction system, and the system is washed three times. The dichloromethane layer is collected, rotary evaporated, and dried. After drying, a powder is obtained, which is a cardanol derivative.

[0053] 2) Synthesis of cardanol-modified furan resin

[0054] In a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, cardanol, cardanol derivatives and KOH aqueous solution are added at a ratio of n(phenols):n(KOH)=1:0.1, wherein the molar ratio of cardanol and cardanol derivatives is n(cardanol):n(cardanol derivatives)=1:0.5. Heat to 70°C under stirring, and add the furfural aqueous solution dropwise to the reaction system at a ratio of n(furfural):n(phenols)=1.75:1 to allow the phenolic compounds and furfural to undergo polycondensation reaction. The dripping speed is preferably such that the temperature of the reaction system does not rise significantly. After reacting for 1.5 hours, furfuryl alcohol is added to react for 1 hour, wherein n(cardanol):n(furfuryl alcohol)=2:1, and the unreacted water and furfural are removed by rotary evaporation at 50°C to obtain a red viscous liquid. Then vacuum dehydration is performed to obtain cardanol-modified furan resin.

[0055] Example 2

[0056] 1) Synthesis of cardanol derivatives

[0057] Dissolve cardanol (3.02 g), thioglycolic acid (1.46 g), and azobisisobutyronitrile (140 mg) in 20 mL of dichloromethane and react at 70°C for 8 h under stirring. After the system is cooled, water is added to the reaction system, and the system is washed three times. The dichloromethane layer is collected, rotary evaporated, and dried. After drying, a powder is obtained, which is the cardanol derivative.

[0058] 2) Synthesis of cardanol-modified furan resin

[0059] In a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, cardanol, cardanol derivatives and KOH aqueous solution are added in a ratio of n(phenols):n(KOH)=1:0.1, and heated to 70°C under stirring, wherein n(cardanol):n(cardanol derivative)=1:1. The furfural aqueous solution is added dropwise to the reaction system in a ratio of n(furfural):n(phenols)=2:1 to allow the phenolic compounds and furfural to undergo polycondensation reaction, and the dropping speed is preferably such that the temperature of the reaction system does not rise significantly. The reaction is carried out for 1.5 hours, and then furfuryl alcohol is added to react for 1 hour, wherein n(cardanol):n(furfuryl alcohol)=1:1. Rotary evaporation is performed at 50°C to remove unreacted water and furfural to obtain a red viscous liquid. Vacuum dehydration is then performed to obtain cardanol-modified furan resin.

[0060] Example 3

[0061] 1) Synthesis of cardanol derivatives

[0062] Dissolve cardanol (3.02 g), thioglycolic acid (1.84 g), and azobisisobutyronitrile (140 mg) in 20 mL of dichloromethane and react at 70°C for 8 h under stirring. After the system is cooled, water is added to the reaction system, and the system is washed three times. The dichloromethane layer is collected, rotary evaporated, and dried. After drying, a powder is obtained, which is the cardanol derivative.

[0063] 2) Synthesis of cardanol-modified furan resin

[0064] In a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, cardanol, cardanol derivatives and KOH aqueous solution are added in a ratio of n(phenols):n(KOH)=1:0.1, and heated to 70°C under stirring, wherein n(cardanol):n(cardanol derivatives)=1:1.5. The furfural aqueous solution is added dropwise to the reaction system in a ratio of n(furfural):n(phenols)=2.25:1 to allow the phenolic compounds and furfural to undergo polycondensation reaction, and the dropping speed is preferably such that the temperature of the reaction system does not rise significantly. The reaction is carried out for 1h, and then furfuryl alcohol is added and reacted for 1h, wherein n(cardanol):n(furfuryl alcohol)=1:1.5. Rotary evaporation is performed at 50°C to remove unreacted water and furfural to obtain a red viscous liquid. Vacuum dehydration is then performed to obtain cardanol-modified furan resin.

[0065] Example 4

[0066] 1) Synthesis of cardanol derivatives

[0067] Dissolve cardanol (3.02 g), thioglycolic acid (0.80 g), and azobisisobutyronitrile (140 mg) in 20 mL of dichloromethane and react at 70°C for 6 h under stirring. After the system is cooled, water is added to the reaction system, and the system is washed three times. The dichloromethane layer is collected, rotary evaporated, and dried. After drying, a powder is obtained, which is the cardanol derivative.

[0068] 2) Synthesis of cardanol-modified furan resin

[0069] In a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, cardanol, cardanol derivatives and KOH aqueous solution are added in a ratio of n(phenols):n(KOH)=1:0.1, and heated to 70°C under stirring, wherein n(cardanol):n(cardanol derivatives)=1:0.7. The furfural aqueous solution is added dropwise to the reaction system in a ratio of n(furfural):n(phenols)=2.25:1 to allow the phenolic compounds and furfural to undergo polycondensation reaction, and the dropping speed is preferably such that the temperature of the reaction system does not rise significantly. The reaction is carried out for 2h, and then furfuryl alcohol is added and reacted for 2h, wherein n(cardanol):n(furfuryl alcohol)=1:1.5. Rotary evaporation is performed at 50°C to remove unreacted water and furfural to obtain a red viscous liquid. Vacuum dehydration is then performed to obtain cardanol-modified furan resin.

[0070] Example 5

[0071] 1) Synthesis of cardanol derivatives

[0072] Dissolve cardanol (3.02 g), thioglycolic acid (1.60 g), and azobisisobutyronitrile (140 mg) in 20 mL of dichloromethane and react at 70°C for 6 h under stirring. After the system is cooled, water is added to the reaction system, and the system is washed three times. The dichloromethane layer is collected, rotary evaporated, and dried. After drying, a powder is obtained, which is the cardanol derivative.

[0073] 2) Synthesis of cardanol-modified furan resin

[0074] In a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, cardanol, cardanol derivatives and KOH aqueous solution are added in a ratio of n(phenols):n(KOH)=1:0.1, and heated to 70°C under stirring, wherein n(cardanol):n(cardanol derivatives)=1:0.9. The furfural aqueous solution is added dropwise to the reaction system in a ratio of n(furfural):n(phenols)=2.25:1 to allow the phenolic compounds and furfural to undergo polycondensation reaction, and the dropping speed is preferably such that the temperature of the reaction system does not rise significantly. The reaction is carried out for 2h, and then furfuryl alcohol is added to react for 1h, wherein n(cardanol):n(furfuryl alcohol)=1:1.5. Rotary evaporation is performed at 50°C to remove unreacted water and furfural to obtain a red viscous liquid. Vacuum dehydration is then performed to obtain cardanol-modified furan resin.

[0075] In some embodiments of the present application, the aldehyde compound may also be other types of aldehyde compounds, such as glyoxal and formaldehyde.

[0076] In some embodiments of the present application, when synthesizing cardanol-modified furan resin, the alkaline catalyst may also be NaOH or ammonia water, or a combination of different types of alkaline catalysts.

[0077] In some embodiments of the present application, when synthesizing cardanol-modified furan resin, a phenolic compound in the phenolic mixture may be, in addition to cardanol, one or more of cardanol, phenol, furfuryl alcohol, resorcinol and o-cresol.

[0078] The technical effects of the present application are further illustrated below in combination with some comparative examples.

[0079] Comparative Example 1

[0080] In a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, add cardanol and KOH aqueous solution at a ratio of n(cardanol):n(KOH)=1:0.1, heat to 70°C under stirring, and drop the furfural aqueous solution into the reaction system at a ratio of n(furfural):n(cardanol)=1.75:1 to make phenol and furfural undergo polycondensation reaction. The dropping speed is suitable for the temperature of the reaction system not to rise significantly. After reacting for 1.5 hours, furfuryl alcohol is subsequently added to react for 1 hour, wherein n(cardanol):n(furfuryl alcohol)=2:1. After stopping the reaction, rotary evaporation is performed at 50°C to remove unreacted water and furfural to obtain a red viscous liquid. Then vacuum dehydration is performed to obtain furan resin.

[0081] Comparative Example 2

[0082] In a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, phenol and KOH aqueous solutions are added in a ratio of n(phenol):n(cardanol):n(KOH)=0.2:0.8:0.1, heated to 70°C under stirring, and the furfural aqueous solution is added dropwise to the reaction system in a ratio of n(furfural):n(phenols)=2:1, so that phenol and furfural undergo polycondensation reaction, and the dropping speed is preferably such that the temperature of the reaction system does not rise significantly. After reacting for 1.5 hours, furfuryl alcohol is subsequently added and reacted for 1 hour, wherein n(cardanol):n(furfuryl alcohol)=1:1. After stopping the reaction, rotary evaporation is performed at 50°C to remove unreacted water and furfural to obtain a red viscous liquid. Then vacuum dehydration is performed to obtain furan resin.

[0083] Comparative Example 3

[0084] In a three-necked flask equipped with a thermometer, a stirrer and a reflux condenser, phenol and KOH aqueous solution are added in a ratio of n(furfuryl alcohol):n(cardanol):n(KOH)=0.2:0.8:0.1, heated to 70°C under stirring, and furfural aqueous solution is added dropwise to the reaction system in a ratio of n(furfural):n(phenol)=2.25:1 to allow phenol and furfural to undergo polycondensation reaction, and the dropping speed is preferably such that the temperature of the reaction system does not rise significantly. After reacting for 1 hour, furfuryl alcohol is subsequently added to react for 1 hour, wherein n(cardanol):n(furfuryl alcohol)=1:1.5. After stopping the reaction, rotary evaporation is performed at 50°C to remove unreacted water and furfural to obtain a red viscous liquid. Vacuum dehydration is then performed to obtain furan resin.

[0085] Examples 1-3 of the present application and ordinary furan resin comparative examples 1-3 were used as adhesives to perform physical and chemical characterization, storage stability and mechanical tests of sand casting products. Raw sand (40 / 70 mesh standard Dalin new silica sand) was used for sand casting in Examples 1-3 and Comparative Examples 1-3, the liquid-to-material ratio was 1.2% (accounting for the proportion of raw sand), the curing agent benzenesulfonic acid was added in an amount of 0.4% (accounting for the proportion of raw sand), the curing time was 24h, and the tensile strength was tested with the cured sand mold 8-shaped sample, and the specific performance indicators are shown in Table 1.

[0086] Table 1 Test performance table

[0087]

[0088] As can be seen from Table 1, the cardanol derivative modified furan resin obtained in the present application has a lower viscosity than the basic control example, and the strength of the molding sand after curing is higher than that of the ordinary furan resin, indicating that its curing speed and strength are improved; in addition, the long-term storage stability of the cardanol derivative modified furan resin is significantly improved compared with the traditional furan resin.

[0089] The preparation method of cardanol-modified furan resin in the present application is to modify cardanol with thioglycolic acid through a thiol-double bond click chemistry reaction, and use it as a raw material to replace part of cardanol to prepare cardanol-modified furan resin. Figure 1 Shown is a schematic diagram of the reaction principle of the cardanol derivatives proposed in this application.

[0090] The cardanol-modified furan resin of the present application not only significantly improves the storage stability of the resin and solves the problem of poor stability, but also achieves significant improvement in mechanical properties through this modification method. This has a huge application space for the practical application of the resin, especially in the casting field.

[0091] Correspondingly, the present application also proposes a cardanol-modified furan resin for casting obtained by the preparation method of the cardanol-modified furan resin for casting, which has the properties described in the above preparation method embodiment.

[0092] In addition, the present application also proposes a cardanol derivative and a method for preparing a cardanol derivative. In practical applications, the corresponding embodiments in the above-mentioned preparation method of the cardanol-modified furan resin for casting can be adopted, and the technical effects are corresponding, which will not be repeated here.

[0093] It should be noted that, in addition to the above-mentioned synthesis method of cardanol-modified furan resin, the cardanol derivatives proposed in this application can also adopt other synthesis methods in the prior art. The core lies in adopting the cardanol derivatives proposed in this application.

[0094] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a cardanol-modified furan resin for casting, characterized in that: include: Cardanol is modified by using thioglycolic acid to undergo a thiol-double bond click chemistry reaction to obtain a cardanol derivative; Reacting a phenolic mixture with an aldehyde compound to obtain a cardanol-modified furan resin; the phenolic mixture comprises the cardanol derivative and a phenolic compound; The phenolic compound is cardanol; Place cardanol, cardanol derivatives and base catalyst in a reaction kettle and heat to 60-120°C; Add aldehyde compound dropwise and continue the reaction for 1-2 h; Add furfuryl alcohol and continue the reaction for 1-2 h; Vacuum dehydration to obtain cardanol-modified furan resin; In the phenol mixture, the molar ratio of cardanol to the cardanol derivative is 1:(0.5-1.5).

2. The method for preparing a cardanol-modified furan resin for casting according to claim 1, characterized in that: The structure of the cardanol derivative is: 。 3. The method for preparing a cardanol-modified furan resin for casting according to claim 1, characterized in that: The method of modifying cardanol by using thioglycolic acid comprises: Dissolve cardanol and thioglycolic acid in dichloromethane, add azobisisobutyronitrile as an initiator, and reflux at 70°C for 6-8 h under stirring; After cooling, add water, extract and wash, and collect the dichloromethane layer; The collected dichloromethane layer is subjected to rotary evaporation, and after drying, a powder is obtained, which is a cardanol derivative.

4. A cardanol-modified furan resin for casting, characterized in that: The present invention is obtained by using the preparation method of the cardanol-modified furan resin for casting as claimed in any one of claims 1 to 3.

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