A kind of synthetic method of hydantoin epoxy resin

Abstract

The present invention relates to the field of chemical technology, and more particularly to a method for synthesizing a hydantoin epoxy resin. Specifically: (1) 5,5-dimethylhydantoin, sodium hydroxide and water are mixed as a standby solution; (2) 1,2,3,4-diepoxybutane, isopropyl alcohol and benzene are sequentially added to a reaction tank and heated to 50-150°C, and kept under reflux for 4h; (3) the standby solution is added dropwise to the reaction tank, and the reaction is continued after the addition is completed, the viscosity of the solution is tested, and the reaction is stopped when it reaches 5-30cp; (4) isopropyl alcohol and benzene are distilled off under reduced pressure to obtain a crude hydantoin epoxy resin; (5) the crude product is refined, and a fine product is obtained after removing sodium hydroxide. The hydantoin epoxy resin obtained by the method has two hydroxyls, is more water-soluble, and has no ether bond and benzene ring, so it has excellent UV resistance and heat resistance, and can be used to produce a water-based epoxy resin coating with good weather resistance, low toxicity and high thermal stability.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical industry, in particular to a method for synthesizing hydantoin epoxy resin. Background Art

[0002] Hydantoin (chemical name: hydantoin) is a five-membered heterocyclic compound containing two nitrogen atoms and possessing a non-benzene nitrogen heterocyclic structure. It was synthesized by Baeyer in 1861. The nitrogen atoms at positions 1 and 3 and the hydrogen at the carbon atom at position 5 in the hydantoin ring are highly reactive and can undergo substitution reactions with electrophilic reagents, resulting in numerous hydantoin derivatives. Hydantoin epoxy resin is one of the main hydantoin derivatives. It is primarily derived from hydantoin or its derivatives by glycidylation. These novel specialty epoxy resins contain hydantoin heterocyclic rings. While retaining the inherent performance properties of epoxy resins, the hydantoin heterocyclic structure imparts excellent electrical insulation, heat resistance, weather resistance, and wear resistance, offering broad application prospects.

[0003] Patent CN101624439A discloses a method for synthesizing a flame-retardant hydantoin epoxy resin. The molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:2-8, a 30% aqueous sodium hydroxide solution is used as a catalyst, and the molar ratio of sodium hydroxide to epichlorohydrin is 1:1-2 (preferably 1:1). 5,5-dimethylhydantoin and epichlorohydrin are dissolved in ethanol, and the temperature is raised to 0-90°C (preferably 50-80°C) in a reactor equipped with an electric stirring device, a reflux condenser, and a constant pressure separatory funnel. Then, 30% sodium hydroxide solution is slowly added dropwise to the reactor, and the reaction is carried out at a constant temperature for 1-8 hours. The reaction mixture is first vacuum desolventized to constant weight, and the sodium chloride solid is separated by filtration to obtain the hydantoin epoxy resin. The hydantoin epoxy resin involved in this invention has certain flame retardancy, but the product has a small epoxy value, poor curing performance and water solubility. In addition, the invention has a low yield and many by-products, resulting in high product production costs, which is not conducive to large-scale promotion.

[0004] Patent CN105837791A discloses a method for preparing a hydantoin epoxy resin, specifically: using 5,5-dimethylhydantoin and epichlorohydrin in a molar ratio of 1:3-10 as raw materials, adding 0.1-1% of the total mass of quaternary ammonium salt of 5,5-dimethylhydantoin and epichlorohydrin as a ring-opening catalyst for epichlorohydrin, heating the reactants to 50-120°C in an oil bath under nitrogen protection to carry out a ring-opening reaction of epichlorohydrin, reacting for 1-5 hours, cooling to 20-40°C, using a low-grade fatty ketone or tetrahydrofuran as a solvent, gradually adding granular sodium hydroxide with a purity higher than 98.5% as a catalyst for the ring-closing reaction in 3-10 batches, all granular sodium hydroxide is added. The total molar amount of pure sodium hydroxide in the sodium hydroxide catalyst is twice the molar amount of 5,5-dimethylhydantoin. Sodium chloride is produced while generating hydantoin epoxy resin. In the presence of a solvent, the material is first filtered to remove some sodium chloride particles. The filtrate is then transferred to a distillation apparatus for vacuum distillation. When the volume is reduced by nearly half and salt precipitation occurs, the product in the evaporator is transferred out, filtered to remove salt, and then transferred to the distillation apparatus for continued vacuum distillation. This vacuum distillation and filtration process is repeated until no salt precipitation is observed in the product. Vacuum distillation is then continued until no solvent evaporates within 1 to 5 minutes, thereby obtaining a liquid hydantoin epoxy resin product with fluidity. This invention can effectively remove sodium chloride particles produced as a by-product during the preparation process and reduce the content of inorganic chlorine, but this method also suffers from the problem of low yield. In addition, the epoxy resin obtained by this method has high viscosity, poor fluidity, and low thermal stability. Summary of the Invention

[0005] In view of the shortcomings and problems of the prior art described above, the present invention provides a novel method for synthesizing hydantoin epoxy resin. The hydantoin epoxy resin of the present invention has two hydroxyl groups, is more water-soluble, and lacks ether bonds or benzene rings. Therefore, it has excellent UV and heat resistance and can be used to produce water-based epoxy resin coatings with excellent weather resistance and high thermal stability, resulting in high economic benefits. The product structural formula is:

[0006]

[0007] The present invention provides a method for synthesizing hydantoin epoxy resin, comprising the following steps:

[0008] (1) Mix 5,5-dimethylhydantoin, sodium hydroxide, and water in a certain proportion to prepare a standby solution;

[0009] (2) adding 1,2,3,4-diepoxybutane, isopropyl alcohol, and benzene into a reaction tank in a certain proportion, heating the reaction tank to a certain temperature for reflux operation, and maintaining reflux for a certain time;

[0010] (3) adding the standby solution to the reaction tank at a certain rate, continuing the reaction after the addition is completed, and testing the solution viscosity. When a certain viscosity is reached, the reaction is stopped;

[0011] (4) distilling off isopropyl alcohol and benzene under reduced pressure to obtain a crude hydantoin epoxy resin;

[0012] (5) The crude product is refined and the sodium hydroxide is removed to obtain the fine product.

[0013] In one embodiment, the mixing ratio of the 5,5-dimethylhydantoin and sodium hydroxide is (3.2-3.6):1.

[0014] In one embodiment, the mixing ratio of water and sodium hydroxide is (5.1-5.4):1.

[0015] In one embodiment, the mixing ratio of the 1,2,3,4-diepoxybutylene and isopropyl alcohol is (4.3-4.6):1.

[0016] In one embodiment, the mixing ratio of isopropyl alcohol and benzene is (2.2-2.5):1.

[0017] In one embodiment, the heating temperature of the reaction tank is 65-110°C.

[0018] In one embodiment, the reflux time is 5 to 30 minutes.

[0019] In one embodiment, the solution viscosity is 10-25 cp.

[0020] The beneficial effects of the present invention are:

[0021] (1) The hydantoin epoxy resin obtained by the present invention has two hydroxyl groups and is more water-soluble;

[0022] (2) The hydantoin epoxy resin obtained by the present invention has no ether bond and benzene ring and has excellent UV resistance and heat resistance;

[0023] (3) The hydantoin epoxy resin obtained by the present invention has good UV resistance and heat resistance, and is widely used. It can be especially used to produce water-based epoxy resin coatings with good weather resistance, low toxicity and high thermal stability, and has high economic benefits. DETAILED DESCRIPTION

[0024] The present invention is further described below with reference to the examples, but these examples shall not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are all commercially available conventional products.

[0025] Example 1

[0026] A method for synthesizing a hydantoin epoxy resin comprises the following steps:

[0027] (1) Add 40 kg of 5,5-dimethylhydantoin, 12.5 kg of sodium hydroxide, and 63.75 kg of water to a 200 L container, stir and mix, and use as a standby solution;

[0028] (2) 56.76 kg of 1,2,3,4-diepoxybutane, 13.2 kg of isopropyl alcohol, and 5.28 kg of benzene were added to a 200 L reaction tank in sequence, and the reaction tank was heated to 65 ° C for reflux operation and maintained at reflux for 5 minutes;

[0029] (3) Add the reserved solution to the reaction tank at 3.5 kg / min. Continue the reaction after the addition is complete and test the solution viscosity. Stop the reaction when it reaches 10 cp.

[0030] (4) distilling off isopropyl alcohol and benzene under reduced pressure to obtain a crude hydantoin epoxy resin;

[0031] (5) The crude product is refined and the sodium hydroxide is removed to obtain the fine product.

[0032] After the above steps, a light yellow liquid hydantoin epoxy resin was obtained. After testing, the product purity was 99.87%, the epoxy value was 0.85 mol / 100 g, and the viscosity was 13.2 cp.

[0033] Example 2

[0034] A method for synthesizing a hydantoin epoxy resin comprises the following steps:

[0035] (1) Add 41.25 kg of 5,5-dimethylhydantoin, 12.5 kg of sodium hydroxide, and 65 kg of water to a 200 L container, stir and mix, and use as a standby solution;

[0036] (2) 58.08 kg of 1,2,3,4-diepoxybutane, 13.2 kg of isopropyl alcohol, and 5.5 kg of benzene were added to a 200 L reaction tank in sequence, and the reaction tank was heated to 73 ° C for reflux operation and maintained at reflux for 5 minutes;

[0037] (3) Add the reserved solution to the reaction tank at 3.5 kg / min. Continue the reaction after the addition is complete and test the solution viscosity. Stop the reaction when it reaches 12 cp.

[0038] (4) distilling off isopropyl alcohol and benzene under reduced pressure to obtain a crude hydantoin epoxy resin;

[0039] (5) The crude product is refined and the sodium hydroxide is removed to obtain the fine product.

[0040] After the above steps, a light yellow liquid hydantoin epoxy resin was obtained. After testing, the product purity was 99.89%, the epoxy value was 0.88 mol / 100 g, and the viscosity was 13.1 cp.

[0041] Example 3

[0042] A method for synthesizing a hydantoin epoxy resin comprises the following steps:

[0043] (1) Add 42.5 kg of 5,5-dimethylhydantoin, 12.5 kg of sodium hydroxide, and 66.25 kg of water to a 200 L container, stir and mix, and use as a standby solution;

[0044] (2) 58.08 kg of 1,2,3,4-diepoxybutane, 13.2 kg of isopropyl alcohol, and 5.74 kg of benzene were added to a 200 L reaction tank in sequence, and the reaction tank was heated to 87 ° C for reflux operation and maintained at reflux for 5 minutes;

[0045] (3) Add the reserved solution to the reaction tank at 3.5 kg / min. Continue the reaction after the addition is complete and test the solution viscosity. Stop the reaction when it reaches 15 cp.

[0046] (4) distilling off isopropyl alcohol and benzene under reduced pressure to obtain a crude hydantoin epoxy resin;

[0047] (5) The crude product is refined and the sodium hydroxide is removed to obtain the fine product.

[0048] After the above steps, a light yellow liquid hydantoin epoxy resin was obtained. After testing, the product purity was 99.85%, the epoxy value was 0.89 mol / 100 g, and the viscosity was 14.1 cp.

[0049] Example 4

[0050] A method for synthesizing a hydantoin epoxy resin comprises the following steps:

[0051] (1) Add 43.75 kg of 5,5-dimethylhydantoin, 12.5 kg of sodium hydroxide, and 66.25 kg of water to a 200 L container, stir and mix, and use as a standby solution;

[0052] (2) 59.4 kg of 1,2,3,4-diepoxybutane, 13.2 kg of isopropyl alcohol, and 5.5 kg of benzene were added to a 200 L reaction tank in sequence, and the reaction tank was heated to 87 ° C for reflux operation and maintained at reflux for 5 minutes;

[0053] (3) Add the reserved solution to the reaction tank at 3.5 kg / min. After the addition is completed, continue the reaction and test the solution viscosity. Stop the reaction when it reaches 18 cp.

[0054] (4) distilling off isopropyl alcohol and benzene under reduced pressure to obtain a crude hydantoin epoxy resin;

[0055] (5) The crude product is refined and the sodium hydroxide is removed to obtain the fine product.

[0056] After the above steps, a light yellow liquid hydantoin epoxy resin was obtained. After testing, the product purity was 99.92%, the epoxy value was 0.90 mol / 100 g, and the viscosity was 13.5 cp.

[0057] Example 5

[0058] A method for synthesizing a hydantoin epoxy resin comprises the following steps:

[0059] (1) Add 43.75 kg of 5,5-dimethylhydantoin, 12.5 kg of sodium hydroxide, and 67.5 kg of water to a 200 L container, stir and mix, and use as a standby solution;

[0060] (2) 60.72 kg of 1,2,3,4-diepoxybutane, 13.2 kg of isopropyl alcohol, and 5.28 kg of benzene were added to a 200 L reaction tank in sequence, and the reaction tank was heated to 95 ° C for reflux operation and maintained at reflux for 22 minutes;

[0061] (3) Add the reserved solution to the reaction tank at 3.5 kg / min. Continue the reaction after the addition is complete and test the solution viscosity. Stop the reaction when it reaches 22 cp.

[0062] (4) distilling off isopropyl alcohol and benzene under reduced pressure to obtain a crude hydantoin epoxy resin;

[0063] (5) The crude product is refined and the sodium hydroxide is removed to obtain the fine product.

[0064] After the above steps, a light yellow liquid hydantoin epoxy resin was obtained. After testing, the product purity was 99.90%, the epoxy value was 0.85 mol / 100 g, and the viscosity was 12.8 cp.

[0065] Example 6

[0066] A method for synthesizing a hydantoin epoxy resin comprises the following steps:

[0067] (1) Add 45 kg of 5,5-dimethylhydantoin, 12.5 kg of sodium hydroxide, and 67.5 kg of water to a 200 L container, stir and mix, and use as a standby solution;

[0068] (2) 60.72 kg of 1,2,3,4-diepoxybutane, 13.2 kg of isopropyl alcohol, and 5.28 kg of benzene were added to a 200 L reaction tank in sequence, and the reaction tank was heated to 110 ° C for reflux operation and maintained at reflux for 30 minutes;

[0069] (3) Add the reserved solution to the reaction tank at 3.5 kg / min. Continue the reaction after the addition is complete and test the solution viscosity. Stop the reaction when it reaches 25 cp.

[0070] (4) distilling off isopropyl alcohol and benzene under reduced pressure to obtain a crude hydantoin epoxy resin;

[0071] (5) The crude product is refined and the sodium hydroxide is removed to obtain the fine product.

[0072] After the above steps, a light yellow liquid hydantoin epoxy resin was obtained. After testing, the product purity was 99.93%, the epoxy value was 0.92 mol / 100 g, and the viscosity was 14.5 cp.

Claims

1. A method for synthesizing a hydantoin epoxy resin, characterized in that: The following steps are involved: (1) Mix 5,5-dimethylhydantoin, sodium hydroxide and water to prepare a standby solution; (2) 1,2,3,4-diepoxybutane, isopropyl alcohol, and benzene were added to the reaction tank in sequence, and the reaction tank was heated to 50-150°C for reflux operation and maintained at reflux for 4 hours; (3) Add the standby solution dropwise to the reaction tank. Continue the reaction after the addition is complete and test the solution viscosity. Stop the reaction when the viscosity reaches 10-25 cp. (4) distilling off isopropyl alcohol and benzene under reduced pressure to obtain a crude hydantoin epoxy resin; (5) The crude product is refined and the sodium hydroxide is removed to obtain the fine product; The mixing ratio of 5,5-dimethylhydantoin and sodium hydroxide is (3.2-3.6):1; the mixing ratio of water and sodium hydroxide is (5.1-5.4):1; the mixing ratio of 1,2,3,4-diepoxybutane and isopropyl alcohol is (4.3-4.6):1; the mixing ratio of isopropyl alcohol and benzene is (2.2-2.5):1; the heating temperature of the reaction tank is 65-110° C.; and the reflux time is 5-30 min.

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