KR101614329B1 - Method for preparing epoxy reactive diluent - Google Patents

Abstract

The present invention relates to a process for preparing low equivalent caranol-modified epoxy reactive diluents and, more particularly, to a process for the preparation of low equivalent caranol-modified epoxy reactive diluents in the presence of low water content sodium hydroxide and sodium hydrosulfite in non- Reactive epoxy diluent with low viscosity and low equivalent weight by minimizing the occurrence of cardanol / hydrolysis and side reactions.

Description

TECHNICAL FIELD The present invention relates to a method for preparing an epoxy reactive diluent,

The present invention relates to a process for preparing low equivalent caranol-modified epoxy reactive diluents and, more particularly, to a process for the preparation of low equivalent caranol-modified epoxy reactive diluents in the presence of low water content sodium hydroxide and sodium hydrosulfite in non- Reactive epoxy diluent with low viscosity and low equivalent weight by minimizing the occurrence of cardanol / hydrolysis and side reactions.

Epoxy resins are excellent in adhesion and electrical properties and are used in a wide range of paints such as electronic parts, automobile parts, ships, automobiles, and construction. However, because epoxy resins show limited rheological properties, viscosity control materials such as organic solvents are indispensably required.

CAROHANOL [Chemical formula: C ₆ H ₄ (OH) - (CH ₂ ) ₇ -CH═CH-CH ₂ -CH═CH (CH ₂ ) ₂ -CH ₃ ] is a phenol compound substituted with a hydrocarbon group, Has a long unsaturated hydrocarbon substituent (C ₁₅ H ₂₇ ) at the meta-position with respect to the phenolic hydroxy group, and its structure is as follows.

[Cardanol]

Since cardanol has phenol characteristics and easily forms cross-linking by the long unsaturated hydrocarbon substituent, it can be used as an eco-friendly raw material replacing petroleum phenol. In particular, it is strong, hard, and excellent in flexibility A coating film having high electrical insulation and high heat resistance can be provided. For example, cadanol-modified epoxy compounds, such as cardanol glycidyl ether, can be used as viscosity modifiers in epoxy coatings, have no emission of volatile organic compounds, participate in curing reactions during final curing of coatings, .

The cardanol glycidyl ether is produced by a secondary reaction in which an epoxide functional group is formed by primary reaction in which epichlorohydrin is additionally bound to cardanol in the presence of an alkali catalyst and intramolecular cyclization reaction of the resultant primary addition product . The specific reaction mechanism is as follows.

[Primary reaction: cardanol / epichlorohydrin addition reaction]

[Secondary reaction: epoxide cyclization reaction]

However, when the caustic soda used as a catalyst in each of the above reaction steps is added in the form of an aqueous solution, water in the caustic soda solution and reaction condensation water generated during the secondary epoxy cyclization reaction cause the reaction intermediate product and the final product, The diesters are hydrolyzed and such hydrolysis products cause problems such as an increase in epoxy equivalent, an increase in side reactant content, and an increase in viscosity as the side reaction proceeds. The hydrolysis reaction mechanism of the reaction intermediate product and the final object is as follows.

[Hydrolysis of Reaction Intermediate Product]

 [Hydrolysis of the final object]

China (PRC) Patent Registration No. 001162419 and Chinese Patent Publication No. 102558102 disclose a process for preparing cardanol glycidyl ether through the above primary and secondary reactions. However, in these Chinese patent documents, 30 to 50% of caustic soda aqueous solution is added to the reactant for 3 to 4 hours and then maintained for 3 to 4 hours, or 8 to 9 hours after the caustic soda aqueous solution is added, In this case, as the exposure time to water becomes longer, the reaction intermediate product and the final object are liable to be hydrolyzed, and the epoxy equivalence of the hydrolysis product due to progress of the side reaction, The reactant content increases and the viscosity increases.

Therefore, there is a demand for development of a technique capable of minimizing the hydrolysis and the side reaction during the caranol / epichlorohydrin addition reaction and the epoxy cyclization reaction.

The present invention has been made to solve the problems of the prior art as described above, and it is an object of the present invention to minimize the occurrence of hydrolysis and side reactions during the caranol / epichlorohydrin addition reaction and the epoxy cyclization reaction for the production of cardanol glycidyl ether It is a technical object to provide a process for producing a low viscosity and low equivalent amount of a cardanol-modified epoxy reactive diluent by minimizing the epoxy equivalence and side reactant content.

In order to accomplish the above object, the present invention provides a method for preparing a cyanuric acid by reacting cardanol with epichlorohydrin in the presence of a non-aqueous polar solvent and sodium hydrosulfite, using sodium hydroxide having a purity of 51 wt% Lt; RTI ID = 0.0 > epoxies < / RTI > reactive diluent.

According to another aspect of the present invention, there is provided a cardanol-modified epoxy reactive diluent prepared by the above method, wherein the epoxy equivalent weight (EEW) is 550 g / eq or less and the viscosity at 25 캜 is 80 cps or less.

According to another aspect of the present invention there is provided a paint composition comprising a cardanol-modified epoxy reactive diluent prepared by the process.

When the cadanol-modified epoxy reactive diluent is prepared according to the present invention, the occurrence of hydrolysis and side reactions during the cadanol / epichlorohydrin addition reaction and the epoxy cyclization reaction can be minimized to minimize the epoxy equivalent and the side reactant content, The cadanol-modified epoxy reactive diluent thus produced has high purity and shows excellent curing reaction participation rate due to high epoxy functional group content (that is, low epoxy equivalent) when applied to epoxy curing type paint, and excellent viscosity control ability And is eco-friendly because it does not emit volatile organic substances.

Hereinafter, the present invention will be described in more detail.

In the process for preparing the cadanol-modified epoxy reactive diluent of the present invention, a non-aqueous polar solvent is used. The non-aqueous polar solvent minimizes hydrolysis by forming a protective colloid in the ether structure and the epoxy structure of the high polarity, which are vulnerable to hydrolysis, in the molecule structure of the cadanol-modified epoxy reactive diluent, thereby preventing moisture contact.

As such a non-aqueous polar solvent, a non-aqueous polar solvent having a low boiling point (for example, a boiling point of 100 DEG C or lower) can be preferably used, and more specifically, methanol, ethanol, isopropanol, .

The amount of the non-aqueous polar solvent to be used is preferably 3 to 15 parts by weight, more preferably 5 to 10 parts by weight, based on 100 parts by weight of cardanol. If the amount of the non-aqueous polar solvent is less than 3 parts by weight based on 100 parts by weight of the amount of cardanol used, the hydrolysis preventing effect may be insufficient. If the amount is more than 15 parts by weight, There may be problems losing.

In the process for preparing a cadanol-modified epoxy reactive diluent of the present invention, sodium hydroxide (or caustic soda) having a purity of 51 wt% or more is used as a catalyst in order to minimize the hydrolysis of the reaction intermediate product and the final object. In the prior art, the reaction of cardanol with epichlorohydrin is promoted by using sodium hydroxide in an aqueous solution state having a purity of 20 to 50% by weight as a catalyst. In this case, the water content in the aqueous sodium hydroxide solution is increased after the reaction, It remains in the reaction system until the step to cause hydrolysis of the reaction intermediate product and the final target product. In the present invention, the purity is at least 51 wt% (upper limit of purity is, for example, 99.9 wt%), preferably at least 60 wt%, more preferably at least 70 wt%, even more preferably at least 80 wt% By using sodium hydroxide of 90 wt% or more (e.g., 98 wt% or more) as a catalyst, the amount of water to be added to the reaction system is lowered compared with the prior art, thereby minimizing occurrence of hydrolysis.

The amount of the sodium hydroxide having a purity of 51 wt% or more is preferably 0.8 to 1.2 molar equivalents, more preferably 0.85 to 1 molar ratio, based on 1 mol of the amount of the cardanol used. If the pouring amount of sodium hydroxide at a purity of 51 wt% or more is less than 0.8 mol per 1 mol of the amount of the cardanol used, the addition reaction and the epoxy ring-closing reaction are not sufficiently carried out and there may be a problem of an increase in epoxy equivalent and an increase in viscosity. The side reaction may be promoted due to the addition, which may lead to an increase in epoxy equivalent and an increase in viscosity.

In the method for producing a cadanol-modified epoxy reactive diluent of the present invention, in order to minimize the hydrolysis occurrence by minimizing the water retention time in the reaction system by shortening the reaction time, sodium hydrosulfite (Na ₂ S ₂ O ₄ ) is used. In the prior art using sodium hydroxide in the form of an aqueous solution having a purity of 20 to 50% by weight as a catalyst, it takes at least 4 hours to 9 hours to complete the addition reaction of cardanol and epichlorohydrin and the epoxide cyclization reaction, There is a problem that the time for moisture to remain in the reaction system becomes excessively long and the frequency of the hydrolysis is increased thereby. In the present invention, the total reaction time is reduced to less than 4 hours (for example, from 100 minutes to 200 minutes, more preferably from 110 minutes to 160 minutes) by using the above-described low equivalent amount of sodium hydroxide and sodium hydrosulfite together as a catalyst So that the occurrence of hydrolysis can be minimized.

The amount of the sodium hydrosulfite used is preferably 0.3 to 3 parts by weight, more preferably 0.5 to 1.5 parts by weight based on 100 parts by weight of the cardanol used amount. If the amount of sodium hydrosulfite used is less than 0.3 part by weight based on 100 parts by weight of the amount of cardanol used, it may be difficult to obtain a sufficient reaction time shortening effect. If the amount is more than 3 parts by weight, There may be a problem.

In the present invention, the reaction of forming a cardanol glycidyl ether from cardanol and epichlorohydrin can be preferably carried out at 60 to 90 ° C, more preferably at 65 to 85 ° C, preferably 100 minutes To 200 minutes, more preferably from 110 minutes to 160 minutes. If the reaction temperature is too low as compared with the above range, the addition reaction and the epoxycyclohexyl ring reaction may not be sufficiently performed to raise the epoxy equivalent and increase the viscosity. If the reaction temperature is too high, the epoxy equivalent and the viscosity may increase due to over- If the time is too short, the addition reaction and the epoxycycloalkane reaction are not sufficiently carried out to raise the epoxy equivalent and increase the viscosity. If the time is too long, the epoxy equivalent increases and the viscosity increases due to excessive reaction, or there is a problem of occurrence of side reaction due to hydrolysis .

According to one embodiment of the present invention, the reaction vessel is charged with cadanol, epichlorohydrin, a non-aqueous polar solvent (for example, methanol) and sodium hydrosulfite and heated to a purity of 51 Sodium hydroxide in an amount of at least 10% by weight (e.g., 98% by weight) is added to the mixture at 50 to 100 minutes while maintaining the temperature at 70 to 80 캜. After completion of the addition of sodium hydroxide, the mixture is maintained at 65 to 75 캜 for 50 to 100 minutes, Diesters can be synthesized.

The method for producing a cadanol-modified epoxy reactive diluent of the present invention is characterized in that after the synthesis of the cardanol glycidyl ether is completed, the water, the solvent and the unreacted material are removed, and the usual post treatment for purifying the reaction product May further comprise one or more steps. According to one embodiment of the present invention, after completion of the synthesis of cardanol glycidyl ether, the reaction system is heated to 120 to 150 ° C to remove moisture in the reaction system, a non-aqueous polar solvent, and unreacted epichlorohydrin, Is reduced to 100 torr or less to completely remove volatile substances. After completion of the removal of the volatiles, the reaction system is cooled to 100 ° C or lower, and an organic solvent (for example, toluene) and water are added thereto for washing. The remaining organic layer is heated again to 120-150 DEG C and reduced to 100 torr or lower to remove the organic solvent used for washing, thereby obtaining a low equivalent amount of a cardanol-modified epoxy reactive diluent.

The epoxy-modified epoxy reactive diluent prepared by the method described above has an epoxy equivalent weight (EEW) of preferably 550 g / eq or less, more preferably 520 g / eq or less, and a viscosity at 25 ° C of preferably 80 cps Or less, more preferably 60 cps or less. Thus, according to another aspect of the present invention, there is provided a cardanol-modified epoxy reactive diluent prepared by the above method, wherein the epoxy equivalent weight (EEW) is 550 g / eq or less and the viscosity at 25 캜 is 80 cps or less.

The cadanol-modified epoxy reactive diluent prepared by the method of the present invention exhibits an excellent curing reaction participation rate due to a high epoxy functional group content (i.e., low epoxy equivalent) when applied to an epoxy curing type paint, It is environmentally friendly because it does not emit volatile organic substances. Accordingly, in accordance with another aspect of the present invention, there is provided a coating composition comprising a cardanol-modified epoxy reactive diluent prepared by the process. In the coating composition of the present invention, the components other than the cadanol-modified epoxy reactive diluent may be those normally used in the epoxy coating composition.

Hereinafter, the present invention will be described more specifically by way of examples. However, these examples are provided only for the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[ Example ]

Example  One

300 g of cadanol, 165 g of epichlorohydrin, 19 g of methanol and 3 g of sodium hydrosulfite were fed into a 1-liter flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a condenser. The temperature was raised to 2 占 폚. After the completion of the heating, 37 g of sodium hydroxide having a purity of 98% by weight was uniformly added thereto at a temperature of 75 ± 5 ° C for 70 ± 10 minutes. After completion of the addition of sodium hydroxide, the reaction system was maintained at 70 占 폚 for 70 占 10 minutes. Thereafter, the temperature of the reaction system was raised to 135 ± 5 ° C to remove water, methanol and unreacted epichlorohydrin in the reaction system, and the volatiles were completely removed by reducing the pressure to less than 100 torr. After completion of the removal of the volatiles, the reaction system was cooled to less than 100 ° C., 237 g of toluene and 232 g of water were added, stirred at 70 ± 5 ° C. for 30 minutes, and the contents were transferred to a separatory funnel and kept for 30 minutes. Thereafter, phase separation of the yellowish brown transparent liquid on the upper side and the colorless transparent water layer on the lower side was confirmed, and the lower aqueous layer was removed by operating the liquid separation funnel valve. The remaining yellowish brown clear liquid was transferred back to the flask, and toluene was removed at 135 ° C ± 5 ° C under reduced pressure of less than 100 torr to prepare a cardanol-modified epoxy reactive diluent. The epoxy equivalent weight (EEW) of the low-equivalent cadanol-modified epoxy reactive diluent thus prepared was 485.3 g / eq and the viscosity at 25 ° C (Brookfield DV Viscometer) was 55 cps.

Example  2

Modified epoxy-reactive diluent was prepared in the same manner as in Example 1, using 100 g of cardanol, 74 g of epichlorohydrin, 6.4 g of methanol, 1 g of sodium hydrosulfite and 14.9 g of sodium hydroxide having a purity of 98% by weight (79 g of toluene and 78 g of water were used for purification and phase separation of the reaction product). The epoxy equivalent (EEW) of the low-equivalent cadanol-modified epoxy reactive diluent thus prepared was 411.3 g / eq and the viscosity at 25 ° C (Brookfield DV Viscometer) was 41 cps.

Example  3

A cadanol-modified epoxy reactive diluent was prepared in the same manner as in Example 1, using 100 g of cardanol, 55 g of epichlorohydrin, 6.4 g of isopropanol, 1 g of sodium hydrosulfite and 12.3 g of sodium hydroxide having a purity of 98% by weight (79 g of toluene and 78 g of water were used for purification and phase separation of the reaction product). The epoxy equivalent weight (EEW) of the low equivalent weight cadanol-modified epoxy reactive diluent thus prepared was 504.3 g / eq and the viscosity at 25 ° C (Brookfield DV Viscometer) was 56 cps.

Comparative Example  One

Denatured epoxy reactive diluent was prepared in the same manner as in Example 1 except that methanol and sodium hydrosulfite were not used and 72 g of an aqueous solution of sodium hydroxide having a purity of 50% by weight was used instead of 37 g of sodium hydroxide having a purity of 98% by weight . The epoxy equivalent (EEW) of the cadanol-modified epoxy reactive diluent thus prepared was 744.9 g / eq and the viscosity at 25 ° C (Brookfield DV Viscometer) was 135 cps.

Claims (8)

Using sodium hydroxide at a purity of 90 wt% or more in the presence of a non-aqueous polar solvent, sodium hydrosulfite as a reaction catalyst, reacting cardanol and epichlorohydrin for 100 minutes to 200 minutes to produce cardanol glycidyl ether Lt; RTI ID = 0.0 > epoxie < / RTI > reactive diluent. The method of claim 1, wherein the non-aqueous polar solvent is selected from methanol, ethanol, isopropanol, and mixtures thereof. The method for producing a cardanol-modified epoxy reactive diluent according to claim 1, wherein the non-aqueous polar solvent is used in an amount of 3 to 15 parts by weight based on 100 parts by weight of the cardanol used amount. delete The method for producing a cardanol-modified epoxy reactive diluent according to claim 1, wherein the amount of the sodium hydrosulfite used is 0.3 to 3 parts by weight based on 100 parts by weight of the cardanol used amount. delete delete delete