A modified epoxy resin and preparation method thereof

Abstract

The present invention belongs to the technical field of epoxy resin materials, and specifically relates to a modified epoxy resin and a preparation method thereof. The present invention provides a modified epoxy resin, which comprises the following preparation raw materials, measured by molar fractions: 1 part of bisphenol A epoxy resin; 1 to 8 parts of epichlorohydrin; 0.01 to 0.4 parts of an ether dilution aid; 1.21 to 2.5 parts of a basic catalyst; the ether dilution aid is an ether dilution aid containing an epoxy group. The modified epoxy resin provided by the present invention has a low viscosity and does not affect the temperature resistance and curing strength of the bisphenol A epoxy resin.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy resin materials, and particularly relates to a modified epoxy resin and a preparation method thereof. Background Art

[0002] Liquid bisphenol A type epoxy resin is widely used in coatings, adhesives, fiberglass, laminates, electronic casting, potting and encapsulation, etc., but liquid bisphenol A type epoxy resin has the defects of high viscosity and poor fluidity.

[0003] At present, the most common method to reduce the viscosity of liquid bisphenol A epoxy resin is to mix the liquid bisphenol A epoxy resin with active / inactive diluents to obtain low-viscosity epoxy resin. However, when active diluents are used, the temperature resistance and curing strength of bisphenol A epoxy resin will be reduced. When inactive diluents are used, a large amount of organic solvents will be introduced into the system. Most epoxy resin solvents are highly volatile, toxic, and irritating, which affects the safety of on-site construction workers and does not meet environmental protection requirements. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a modified epoxy resin and a preparation method thereof. The modified epoxy resin provided by the present invention has a low viscosity and does not affect the temperature resistance and curing strength of the bisphenol A epoxy resin.

[0005] In order to solve the above problems, the present invention provides a modified epoxy resin, which includes the following preparation raw materials, measured by molar fractions: 1 part of bisphenol A epoxy resin; 1 to 8 parts of epichlorohydrin; 0.01 to 0.4 parts of an ether dilution aid; and 1.21 to 2.5 parts of an alkaline catalyst; the ether dilution aid is an ether dilution aid containing an epoxy group.

[0006] Preferably, the molecular weight of the ether dilution aid is 100-500.

[0007] Preferably, the ether dilution aid comprises a glycidyl ether compound.

[0008] Preferably, the alkaline catalyst includes one or more of sodium hydroxide, potassium hydroxide and sodium carbonate.

[0009] Preferably, the average molecular weight of the bisphenol A epoxy resin is 3100-7000.

[0010] The present invention also provides a method for preparing the modified epoxy resin described above, comprising the following steps:

[0011] Mixing bisphenol A epoxy resin, epichlorohydrin, ether dilution aid and part of alkaline catalyst under protective atmosphere, and pre-reacting the obtained reaction liquid to obtain epoxy resin precursor;

[0012] The epoxy resin precursor and the remaining alkaline catalyst are mixed to carry out a ring-forming reaction to obtain a modified epoxy resin.

[0013] Preferably, the pre-reaction temperature is 20-80° C. and the time is 1.4-1.6 h.

[0014] Preferably, the conditions for the cyclization reaction include: temperature of 20 to 80° C., pressure of 10 to 50 kPa, and time of 1 to 8 h.

[0015] Preferably, after the cyclization reaction, the crude resin mixture obtained by the cyclization reaction is purified.

[0016] Preferably, the purification method is extraction.

[0017] The present invention provides a modified epoxy resin, which comprises the following raw materials in terms of molar fractions: 1 part of bisphenol A epoxy resin; 1 to 8 parts of epichlorohydrin; 0.01 to 0.4 parts of ether dilution aid; 1.21 to 2.5 parts of alkaline catalyst; the ether dilution aid is an ether dilution aid containing epoxy groups. The modified epoxy resin provided by the present invention introduces a small amount of low molecular weight alcohol compounds (produced by decomposition of the ether dilution aid) into the modified epoxy resin chain. The introduced alcohol compounds have low molecular weight and few chain segments, thereby reducing the viscosity of the modified epoxy resin. At the same time, since the amount of the alcohol compound introduced into the modified epoxy resin is very small, it will not affect the combination of epichlorohydrin and bisphenol A epoxy resin, thereby not affecting the temperature resistance and curing strength of the bisphenol A epoxy resin.

[0018] The data of the examples show that the rotational viscosity of the modified epoxy resin provided by the present invention is in the range of 8000 to 9500 mPa·s. DETAILED DESCRIPTION

[0019] The present invention provides a modified epoxy resin, which comprises the following preparation raw materials, measured by mole fraction:

[0020] 1 part of bisphenol A epoxy resin;

[0021] 1 to 8 parts of epichlorohydrin;

[0022] 0.01 to 0.4 parts of ether dilution aid;

[0023] 1.21-2.5 parts of basic catalyst;

[0024] The ether dilution aid is an ether dilution aid containing an epoxy group.

[0025] In the present invention, the raw material for preparing the modified epoxy resin includes 1 part of bisphenol A epoxy resin by mole fraction. In the present invention, the bisphenol A epoxy resin is preferably in liquid state. In the present invention, the average molecular weight of the bisphenol A epoxy resin is preferably 3100 to 7000, more preferably 4200 to 6000.

[0026] In the present invention, the raw materials for preparing the modified epoxy resin include 1 to 8 parts of epichlorohydrin, preferably 2 to 7 parts, by mole.

[0027] In the present invention, the raw materials for preparing the modified epoxy resin include 0.01 to 0.4 parts of ether dilution aids, preferably 0.02 to 0.3 parts, by mole fraction. In the present invention, the molecular weight of the ether dilution aid is preferably 100 to 500, more preferably 150 to 450. The ether dilution aid preferably includes a glycidyl ether compound, and the glycidyl ether compound preferably includes one or more of cardanol glycidyl ether, allyl glycidyl ether, methacrylate glycidyl ether, n-butyl glycidyl ether, diglycidyl ether, methyl glycidyl ether and p-isobutylphenyl glycidyl ether, more preferably cardanol glycidyl ether, allyl glycidyl ether or methacrylate glycidyl ether.

[0028] In the present invention, the raw materials for preparing the modified epoxy resin include 1.21 to 2.5 parts of alkaline catalyst, preferably 1.25 to 2 parts, by mole fraction. In the present invention, the alkaline catalyst preferably includes one or more of sodium hydroxide, potassium hydroxide and sodium carbonate. In the present invention, the alkaline catalyst is preferably used in the form of an aqueous solution of the alkaline catalyst. In the present invention, the mass concentration of the alkaline catalyst in the aqueous solution of the alkaline catalyst is preferably 15 to 50%, more preferably 20 to 40%.

[0029] The present invention also provides a method for preparing the modified epoxy resin described above, comprising the following steps:

[0030] Mixing bisphenol A epoxy resin, epichlorohydrin, ether dilution aid and part of alkaline catalyst under protective atmosphere, and pre-reacting the obtained reaction liquid to obtain epoxy resin precursor;

[0031] The epoxy resin precursor and the remaining alkaline catalyst are mixed to carry out a ring-forming reaction to obtain a modified epoxy resin.

[0032] The invention mixes bisphenol A epoxy resin, epichlorohydrin, ether dilution aid and part of alkaline catalyst under protective atmosphere, and pre-reacts the obtained reaction liquid to obtain epoxy resin precursor.

[0033] In the present invention, the pre-reaction is a grafting reaction between the epoxy groups in the ether dilution auxiliary agent and the phenol groups in the bisphenol A type epoxy resin.

[0034] In the present invention, the protective atmosphere is preferably one of nitrogen, helium or argon. In the present invention, the molar ratio of the bisphenol A epoxy resin to part of the alkaline catalyst is preferably 1:0.01-0.5, more preferably 1:0.1-0.3.

[0035] In the present invention, the mixing temperature is preferably 20 to 80°C, more preferably 30 to 60°C.

[0036] In the present invention, the temperature of the pre-reaction is preferably 20 to 80° C., more preferably 30 to 60° C., and the time is preferably 1.4 to 1.6 h, more preferably 1.5 h.

[0037] After obtaining the epoxy resin precursor, the present invention mixes the epoxy resin precursor with the remaining alkaline catalyst to carry out a ring-forming reaction to obtain a modified epoxy resin.

[0038] In the present invention, the mixing is preferably performed by dripping the remaining alkaline catalyst into the epoxy resin precursor. In the present invention, the dripping rate is preferably 0.5 to 0.9 g / min, more preferably 0.6 to 0.8 g / min.

[0039] In the present invention, the molar ratio of the bisphenol A epoxy resin to the remaining alkaline catalyst is preferably 1:1.2-2.0, more preferably 1:1.5-1.8.

[0040] In the present invention, the conditions for the cyclization reaction preferably include a temperature of preferably 20 to 80° C., more preferably 30 to 70° C., a pressure of preferably 10 to 50 kPa, and a time of preferably 1 to 8 h, more preferably 2 to 6 h.

[0041] In the present invention, the cyclization reaction is a reaction between a base and a chlorinated hydroxyl group to form a ring.

[0042] In the present invention, after the cyclization reaction, the process preferably further comprises desolventizing the product obtained from the cyclization reaction to remove excess epichlorohydrin to obtain a crude resin mixture.

[0043] In the present invention, the conditions for removing excess epichlorohydrin by desolventizing include: the temperature is preferably 80 to 200° C., more preferably 100 to 150° C. The pressure is preferably 1 to 30 kPa, more preferably 10 to 20 kPa.

[0044] In the present invention, after obtaining the crude resin mixture, it is preferred to further purify the crude resin mixture.

[0045] In the present invention, the purification method is preferably extraction. In the present invention, the extractant is preferably a mixture of water and an organic solvent. In the present invention, the organic solvent and water are immiscible. In the present invention, the organic solvent is preferably a benzene solvent and / or a ketone solvent. In the present invention, the benzene solvent is preferably one or more of toluene, xylene, styrene and benzyl alcohol. In the present invention, the ketone solvent preferably includes acetone and / or butanone. In the present invention, the mass ratio of water to organic solvent in the extractant is preferably 4:2 to 4, more preferably 4:3. In the present invention, the number of extractions is preferably 2 times. In the present invention, it is preferred to combine the organic phases obtained by extraction for treatment.

[0046] In the present invention, after the extraction, preferably the process further comprises removing the solvent from the organic phase obtained by the extraction.

[0047] In the present invention, the conditions for removing the solvent include: the temperature is preferably 100-200° C., more preferably 150-180° C., and the pressure is preferably 1-30 kPa, more preferably 10-20 kPa.

[0048] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0049] Example 1

[0050] Under N2 protection, 601g of epichlorohydrin, 228g of bisphenol A epoxy resin (average molecular weight of 5660), and 5.7g of methyl glycidyl ether (the amount of methyl glycidyl ether is 1% of the amount of epichlorohydrin) were mixed, heated to 60°C, 10g of 50wt.% NaOH solution was added, and the mixture was kept warm at 60°C for 1.5h to obtain a reaction solution.

[0051] Under the conditions of 62.5°C and 19.5kPa, 130g of 50wt.% NaOH solution was added dropwise to the above reaction solution at a dropping rate of 0.7g / min to carry out cyclization reaction for 3h, and then the product obtained by the cyclization reaction was desolventized to remove excess epichlorohydrin at 150°C and 5kPa to obtain a crude resin mixture.

[0052] The crude resin mixture was dissolved in 400 g toluene and 300 g water, poured into a separatory funnel to separate the layers, the upper toluene layer was taken and 300 g water was added, the layers were washed with water, the upper toluene layer was taken and desolventized at 130°C and 5 kPa, and after removing the toluene and a small amount of water, a low-viscosity modified epoxy resin was obtained.

[0053] The epoxy equivalent of the modified epoxy resin was measured to be 186.9 g / eq, the hydrolyzable chlorine content was 98 ppm, the rotational viscosity was 9053 mPa·s, and the glass transition temperature was 133°C and the flexural strength was 552 N / m when dicyandiamide and imidazole were used as curing agents. 2 .

[0054] Example 2

[0055] Under N2 protection, 601 g of epichlorohydrin, 228 g of bisphenol A epoxy resin (average molecular weight of 5660), and 20.8 g of cardanol glycidyl ether (the amount of substance is 1% of the amount of epichlorohydrin) were mixed, heated to 60°C, 10 g of 50 wt.% NaOH solution was added, and the mixture was kept warm at 60°C for 1.5 h to obtain a reaction solution.

[0056] Under the conditions of 62.5°C and 19.5kPa, 130g of 50wt.% NaOH solution was added dropwise to the above reaction solution at a dropping rate of 0.7g / min to carry out cyclization reaction for 3h, and then the product obtained by the cyclization reaction was desolventized to remove excess epichlorohydrin at 150°C and 5kPa to obtain a crude resin mixture.

[0057] The crude resin mixture was dissolved in 400 g toluene and 300 g water, poured into a separatory funnel to separate the layers, the upper toluene layer was taken and further 200 g water was added, the layers were washed with water, the upper toluene layer was taken and desolventized at 130°C and 5 kPa, and after removing the toluene and a small amount of water, a low-viscosity modified epoxy resin was obtained.

[0058] The epoxy equivalent of the modified epoxy resin was measured to be 187.9 g / eq, the hydrolyzable chlorine content was 82 ppm, the rotational viscosity was 8532 mPa·s, and the glass transition temperature was 136°C and the flexural strength was 574 N / m when dicyandiamide and imidazole were used as curing agents. 2 .

[0059] Example 3

[0060] Under N2 protection, 462 g of epichlorohydrin, 228 g of bisphenol A epoxy resin (average molecular weight of 5660), and 7.4 g of allyl glycidyl ether (the amount of substance is 1% of the amount of epichlorohydrin) were mixed, heated to 60°C, 15 g of 50 wt.% NaOH solution was added, and the mixture was kept warm at 60°C for 1.5 h to obtain a reaction solution.

[0061] Under the conditions of 62.5°C and 19.5kPa, 130g of 50wt.% NaOH solution was added dropwise to the above reaction solution at a dropping rate of 0.7g / min to carry out cyclization reaction for 3h, and then the product obtained by the cyclization reaction was desolventized to remove excess epichlorohydrin at 150°C and 5kPa to obtain a crude resin mixture.

[0062] The crude resin mixture was dissolved in 400 g toluene and 300 g water, poured into a separatory funnel to separate the layers, the upper toluene layer was taken and further 200 g water was added, the layers were washed with water, the upper toluene layer was taken and desolventized at 130°C and 5 kPa, and after removing the toluene and a small amount of water, a low-viscosity modified epoxy resin was obtained.

[0063] The epoxy equivalent of the modified epoxy resin was measured to be 187.2 g / eq, the hydrolyzable chlorine content was 83 ppm, the rotational viscosity was 8023 mPa·s, and the glass transition temperature was 134°C and the flexural strength was 567 N / m when dicyandiamide and imidazole were used as curing agents. 2 .

[0064] Example 4

[0065] Under N2 protection, 462 g of epichlorohydrin, 228 g of bisphenol A epoxy resin, and 9.2 g of glycidyl methacrylate (the amount of substance is 1% of the amount of epichlorohydrin) were mixed, heated to 60°C, 10 g of 50 wt.% NaOH solution was added, and the mixture was kept warm at 60°C for 1.5 h to obtain a reaction solution.

[0066] Under the conditions of 62.5°C and 19.5kPa, 130g of 50wt.% NaOH solution was added dropwise to the above reaction solution at a dropping rate of 0.7g / min to carry out cyclization reaction for 3h, and then the product obtained by the cyclization reaction was desolventized to remove excess epichlorohydrin at 150°C and 5kPa to obtain a crude resin mixture.

[0067] The crude resin mixture was dissolved in 400 g toluene and 300 g water, poured into a separatory funnel to separate the layers, the upper toluene layer was taken and further 200 g water was added, the layers were washed with water, the upper toluene layer was taken and desolventized at 130°C and 5 kPa, and after removing the toluene and a small amount of water, a low-viscosity modified epoxy resin was obtained.

[0068] The epoxy equivalent of the modified epoxy resin was measured to be 185.2 g / eq, the hydrolyzable chlorine content was 92 ppm, the rotational viscosity was 8121 mPa·s, and the glass transition temperature was 140°C and the flexural strength was 592 N / m when dicyandiamide and imidazole were used as curing agents. 2 .

[0069] Example 5

[0070] Under N2 protection, 462 g of epichlorohydrin, 228 g of bisphenol A epoxy resin (average molecular weight of 5660), 2.85 g of methyl glycidyl ether and 3.7 g of allyl glycidyl ether (the amount of each substance is 0.5% of the amount of epichlorohydrin) are mixed, heated to 60°C, 10 g of 50 wt.% NaOH solution is added, and the mixture is kept warm at 60°C for 100 min to obtain a reaction solution.

[0071] Under the conditions of 62.5°C and 19.5kPa, 130g of 50wt.% NaOH solution was added dropwise to the above reaction solution at a dropping rate of 0.7g / min to carry out cyclization reaction for 3h, and then the product obtained by the cyclization reaction was desolventized to remove excess epichlorohydrin at 150°C and 5kPa to obtain a crude resin mixture.

[0072] The crude resin mixture was dissolved in 400 g toluene and 300 g water, poured into a separatory funnel to separate the layers, the upper toluene layer was taken and further 200 g water was added, the layers were washed with water, the upper toluene layer was taken and desolventized at 130°C and 5 kPa, and after removing the toluene and a small amount of water, a low-viscosity modified epoxy resin was obtained.

[0073] The epoxy equivalent of the modified epoxy resin was measured to be 186.6 g / eq, the hydrolyzable chlorine content was 98 ppm, the rotational viscosity was 9053 mPa·s, and the glass transition temperature was 139°C and the flexural strength was 578 N / m when dicyandiamide and imidazole were used as curing agents. 2 .

[0074] Example 6

[0075] Under N2 protection, 462 g of epichlorohydrin, 228 g of bisphenol A epoxy resin (average molecular weight of 5660), 10.4 g of cardanol glycidyl ether and 4.6 g of methacrylate glycidyl ether (the amount of each substance is 0.5% of the amount of epichlorohydrin substance) were mixed, heated to 60°C, 10 g of 50 wt.% NaOH solution was added, and the mixture was kept warm at 60°C for 100 min to obtain a reaction solution.

[0076] Under the conditions of 62.5°C and 19.5kPa, 130g of 50wt.% NaOH solution was added dropwise to the above reaction solution at a dropping rate of 0.7g / min to carry out cyclization reaction for 3h, and then the product obtained by the cyclization reaction was desolventized to remove excess epichlorohydrin at 150°C and 5kPa to obtain a crude resin mixture.

[0077] The crude resin mixture was dissolved in 400 g toluene and 300 g water, poured into a separatory funnel to separate the layers, the upper toluene layer was taken and 300 g water was added, the layers were washed with water, the upper toluene layer was taken and desolventized at 130°C and 5 kPa, and after removing the toluene and a small amount of water, a low-viscosity modified epoxy resin was obtained.

[0078] The epoxy equivalent of the modified epoxy resin was measured to be 185.2 g / eq, the hydrolyzable chlorine content was 86 ppm, the rotational viscosity was 9422 mPa·s, and the glass transition temperature was 136°C and the flexural strength was 564 N / m when dicyandiamide and imidazole were used as curing agents. 2 .

[0079] Comparative Example 1

[0080] Under N2 protection, 462 g of epichlorohydrin and 228 g of bisphenol A epoxy resin (average molecular weight 5660) were mixed, heated to 60°C, 10 g of 50 wt.% NaOH solution was added, and the mixture was kept at 60°C for 1.5 h to obtain a reaction solution.

[0081] Under the conditions of 62.5°C and 19.5kPa, 130g of 50wt.% NaOH solution was added dropwise to the above reaction solution at a dropping rate of 0.7g / min to carry out cyclization reaction for 3h, and then the product obtained by the cyclization reaction was desolventized to remove excess epichlorohydrin at 150°C and 5kPa to obtain a crude resin mixture.

[0082] The crude resin mixture was dissolved in 400 g toluene and 300 g water, poured into a separatory funnel to separate the layers, the upper toluene layer was taken and then 300 g of water was added, the layers were washed with water, the upper toluene layer was taken and desolventized at 130°C and 5 kPa, and after removing the toluene and a small amount of water, a low-viscosity modified epoxy resin was obtained.

[0083] The epoxy equivalent of the modified epoxy resin was measured to be 188.2 g / eq, the hydrolyzable chlorine content was 130 ppm, the rotational viscosity was 13940 mPa·s, and the glass transition temperature was 135°C and the flexural strength was 565 N / m when dicyandiamide and imidazole were used as curing agents. 2 .

[0084] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A modified epoxy resin, characterized in that: In terms of molar fractions, the following raw materials are included: 1 part of bisphenol A epoxy resin; 1 to 8 parts of epichlorohydrin; 0.01 to 0.4 parts of ether dilution aid; 1.21-2.5 parts of basic catalyst; The ether dilution aid is methyl glycidyl ether, cardanol glycidyl ether, allyl glycidyl ether or methacrylate glycidyl ether; The preparation method of the modified epoxy resin comprises the following steps: Mixing bisphenol A epoxy resin, epichlorohydrin, ether dilution aid and part of alkaline catalyst under protective atmosphere, and pre-reacting the obtained reaction liquid to obtain epoxy resin precursor; The epoxy resin precursor and the remaining alkaline catalyst are mixed to carry out a ring-forming reaction to obtain a modified epoxy resin.

2. The modified epoxy resin according to claim 1, characterized in that The molecular weight of the ether dilution aid is 100-500.

3. The modified epoxy resin according to claim 1, characterized in that The alkaline catalyst includes one or more of sodium hydroxide, potassium hydroxide and sodium carbonate.

4. The modified epoxy resin according to claim 1, characterized in that The average molecular weight of the bisphenol A epoxy resin is 3100-7000.

5. The method for preparing the modified epoxy resin according to any one of claims 1 to 4, characterized in that: The following steps are involved: Mixing bisphenol A epoxy resin, epichlorohydrin, ether dilution aid and part of alkaline catalyst under protective atmosphere, and pre-reacting the obtained reaction liquid to obtain epoxy resin precursor; The epoxy resin precursor and the remaining alkaline catalyst are mixed to carry out a ring-forming reaction to obtain a modified epoxy resin.

6. The preparation method according to claim 5, characterized in that: The temperature of the pre-reaction is 20-80° C., and the time is 1.4-1.6 hours.

7. The preparation method according to claim 5, characterized in that: The conditions of the cyclization reaction include: temperature of 20 to 80° C., pressure of 10 to 50 kPa, and time of 1 to 8 hours.

8. The preparation method according to claim 5, characterized in that: After the cyclization reaction, the method further comprises purifying the crude resin mixture obtained from the cyclization reaction.

9. The preparation method according to claim 8, characterized in that: The purification is extraction.