Coal tar mixed phenol novolac epoxy resin as well as preparation method and application thereof

Abstract

The invention discloses coal tar mixed phenol novolac epoxy resin as well as a preparation method and application thereof. The preparation method of the coal tar mixed phenol novolac epoxy resin comprises the following steps: S1, in an inert atmosphere, mixing and stirring refined coal tar mixed phenol, a solvent and an acid catalyst, then adding an aldehyde solution, and reacting to obtain phenolic resin; s2, in an inert atmosphere, mixing and stirring phenolic resin, a phase transfer catalyst and epoxy chloropropane, preheating to 70-100 DEG C, reacting for 1-4 hours, cooling to 65-70 DEG C, dropwise adding a basic catalyst, heating to 80-85 DEG C, continuously reacting for 2-3 hours, and naturally cooling; and carrying out post-treatment. According to the preparation method and application of the coal tar mixed phenol novolac epoxy resin, operation is easy and convenient, control is easy, and batch production can be achieved conveniently; in addition, the refined coal tar mixed phenol is low in price, the production cost of the anticorrosive paint is greatly reduced, the performance of the paint is improved, and the economic benefits of enterprises are improved.

Description

Technical Field

[0001] The invention relates to a coal tar mixed phenol-based novolac epoxy resin and a preparation method and application thereof, belonging to the technical field of synthetic resins. Background Art

[0002] Novolac epoxy resin is widely used in various fields of daily life and high-tech due to its excellent dimensional stability, mechanical properties, thermal properties, bonding properties and chemical corrosion resistance, including electronic packaging, adhesives, paints and coatings, circuit board printing, structural materials, aerospace, advanced composite materials, etc. However, as an important chemical raw material for the production of novolac epoxy resin, the output and use direction of phenol and its high price have a great impact on the output of novolac epoxy resin. Therefore, finding a cheap phenol source will have far-reaching significance for alleviating the generation and application of novolac epoxy resin.

[0003] As the world's oil resources gradually decrease, coal tar, as a valuable chemical raw material, is becoming increasingly prominent. Coal tar is the main by-product of coal thermal cracking, and the mixed phenol fraction in coal tar is mainly composed of phenol, o-cresol, m-cresol, xylenol, 3,5-xylenol, etc. Analysis of the chemical structure of these phenolic compounds shows that there are unsubstituted vacancies on the o- / p-benzene rings of the phenolic hydroxyl group (-OH), so that they can be modified through the structure to make them a suitable phenol source to achieve the preparation of coal tar mixed phenol-based novolac epoxy resin. How to further utilize the phenols in coal tar in an economical, reasonable and environmentally friendly manner has become the focus of attention and research in various countries. Summary of the invention

[0004] The invention aims to provide a coal tar mixed phenol-based novolac epoxy resin, which effectively solves the problems of high raw material toxicity and poor performance in the synthesis process of the novolac epoxy resin by utilizing low-cost coal tar mixed phenol as a raw material.

[0005] The preparation method of the coal tar mixed phenolic novolac epoxy resin provided by the present invention comprises the following steps:

[0006] S1. In an inert atmosphere, clean coal tar mixed phenol, a solvent and an acid catalyst are mixed and stirred, and then an aldehyde solution is added to react to obtain a phenolic resin;

[0007] S2. Under an inert atmosphere, the phenolic resin, phase transfer catalyst and epichlorohydrin are mixed and stirred, preheated to 70-100°C, reacted for 1-4 hours, cooled to 65-70°C, added with an alkaline catalyst, heated to 80-85°C, continued to react for 2-3 hours, and cooled naturally; the coal tar mixed phenol-based phenolic epoxy resin is obtained through post-treatment.

[0008] Wherein, the clean coal tar mixed phenol is obtained by distilling the coal tar mixed phenol obtained by thermal cracking of coal under reduced pressure;

[0009] The conditions for the vacuum distillation are: a pressure of 0.085-0.1 MPa and a temperature of 100-120° C.; suitable vacuum distillation pressure and temperature facilitate the removal of light components in the crude coal tar mixed phenol, thereby avoiding adverse effects on the synthesis reaction.

[0010] In the above-mentioned preparation method, in step S1, the mass ratio of the clean coal tar mixed phenol to the aldehyde is 1:0.2-0.4;

[0011] The mass ratio of the clean coal tar mixed phenol to the solvent is 1:0.1-0.5;

[0012] The mass ratio of the clean coal tar mixed phenol to the acid catalyst is 1:0.01-0.2.

[0013] In the above preparation method, in step S1, the solvent is acetone or dichloromethane;

[0014] The acid catalyst is sulfuric acid, hydrochloric acid, oxalic acid or p-toluenesulfonic acid;

[0015] The aldehydes are formaldehyde, furfural, benzaldehyde or butyraldehyde.

[0016] In the above preparation method, in step S1, the reaction temperature is 60-110°C and the reaction time is 1.5-8h;

[0017] After the reaction is completed, the phenolic resin is obtained by natural cooling, removing water and vacuum drying.

[0018] In the above preparation method, in step S2, the alkaline catalyst is a sodium hydroxide aqueous solution with a concentration of 30-40%, and the molar amount of sodium hydroxide is 20-25% of the epichlorohydrin;

[0019] The dropping speed of the alkaline catalyst is 0.2-0.3 mL / min. The adding method of the alkaline catalyst has a great influence on the performance of the synthetic resin. If the alkaline catalyst is added at one time or the dropping speed is too fast, the reaction solution is prone to emulsification, the by-products increase, and the product performance is affected.

[0020] In the above preparation method, in step S2, the phase transfer catalyst is tetrabutylammonium bromide or benzyltrimethylammonium chloride.

[0021] In the above preparation method, in step S2, the post-treatment comprises the following steps:

[0022] The excess epichlorohydrin and water in the reaction system are removed by distillation under reduced pressure, and then 15-25% by mass of toluene is added for dilution to remove the byproduct NaCl (the byproduct NaCl solid is removed by suction filtration) and the catalyst NaOH solid, and then the toluene is removed by distillation under reduced pressure.

[0023] On the basis of the coal tar mixed phenolic novolac epoxy resin provided by the present invention, the present invention further provides a coal tar mixed phenolic novolac epoxy resin coating, which is made of component A and component B;

[0024] The component A comprises the coal tar mixed phenolic novolac epoxy resin and solvent A;

[0025] The component B comprises an epoxy resin curing agent and a solvent B;

[0026] The molar ratio of the epoxy groups in the coal tar mixed phenol novolac epoxy resin to the epoxy resin curing agent is 1:1 to 1:1.5.

[0027] Preferably, the mass fraction of component A is as follows:

[0028] 80-100 parts of coal tar mixed phenol-based epoxy resin, 15-20 parts of solvent A;

[0029] The mass parts of the component B are as follows:

[0030] 80-100 parts of epoxy resin curing agent, 20-30 parts of solvent B;

[0031] The solvent A and the solvent B are at least one of toluene, benzene, xylene, ethylbenzene, acetone, butanone, benzyl alcohol, n-butanol or a mixture of two of these solvents;

[0032] The epoxy resin curing agent is at least one of 2041 cardanol modified curing agent, T-31 phenol amine curing agent, polyether amine (C16) and diaminodiphenyl sulfone (DDS), preferably 2041 cardanol modified curing agent.

[0033] The preparation method of the coal tar mixed phenolic novolac epoxy resin coating comprises the following steps:

[0034] The component A is mixed with the component B, and the obtained mixture is vacuum degassed and then pre-cured and cured in sequence to obtain the product.

[0035] The degassing time is 0.5 to 1 hour;

[0036] The pre-curing temperature is 60-100°C and the time is 1-2h;

[0037] The curing includes low temperature curing and high temperature curing performed sequentially;

[0038] The low-temperature curing temperature is room temperature and the time is 40 to 60 hours, and the high-temperature curing temperature is 60 to 100° C. and the time is 1 to 3 hours.

[0039] Compared with the prior art, the present invention has the following beneficial technical effects:

[0040] 1. The coal tar mixed phenol-based epoxy resin of the present invention is prepared by adding refined coal tar mixed phenol to partially or completely replace bisphenol A and epichlorohydrin for polycondensation reaction, thereby reducing the amount of bisphenol A used or not adding bisphenol A at all, improving the performance of the epoxy resin, opening up a new field for the high-value utilization of coal tar mixed phenol, reducing environmental pollution, turning waste into treasure, reducing production costs, and improving economic benefits.

[0041] 2. The preparation method and application of the coal tar mixed phenol-based novolac epoxy resin provided by the present invention are simple to operate, easy to control, and convenient to realize mass production; in addition, the price of refined coal tar mixed phenol is cheap, which greatly reduces the production cost of anti-corrosion coatings, improves the performance of coatings, and improves the economic benefits of enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The infrared images of the coal tar mixed phenol-based linear phenolic resin (PR) and the coal tar mixed phenol-based novolac epoxy resin (PER) provided by the present invention.

[0043] Figure 2 These are infrared images of commercially available phenolic epoxy resin Y44-80 (CPER) and coal tar mixed phenolic phenolic epoxy resin (PER).

[0044] Figure 3 Coal tar mixed phenolic novolac epoxy resin 1 HNMR spectrum.

[0045] Figure 4 This is a physical picture of the coating obtained after curing the coal tar mixed phenolic novolac epoxy resin prepolymer provided by the present invention and the commercially available Y44-80 novolac epoxy resin.

[0046] Figure 5 This is a test diagram of the adhesion of the coating obtained after curing the coal tar mixed phenol-based epoxy resin prepolymer provided by the present invention and the commercially available Y44-80 phenolic epoxy resin.

[0047] Figure 6 This is a test chart of the impact resistance of the coating obtained after curing the coal tar mixed phenol-based epoxy resin prepolymer provided by the present invention and the commercially available Y44-80 phenolic epoxy resin.

[0048] Figure 7This is a test chart of the bending resistance of the coating obtained after curing the coal tar mixed phenol-based epoxy resin prepolymer provided by the present invention and the commercially available Y44-80 phenolic epoxy resin. DETAILED DESCRIPTION

[0049] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0050] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0051] The detection method in the following embodiments is as follows:

[0052] Structural characterization: Infrared spectroscopy and 1 Coal tar mixed phenolic novolac epoxy resin prepolymer was characterized by HNMR.

[0053] Epoxy value test: The epoxy value of coal tar mixed phenolic novolac epoxy resin prepolymer was tested by perchloric acid-tetraethylammonium bromide anhydrous titration method.

[0054] Coating performance test: The basic properties of the coating include coating thickness, adhesion, impact resistance, hardness, etc. Adhesion is tested according to GB / T9286-1998 "Scratching test for paint and varnish film"; impact resistance is tested according to GB / T 1732-1993 "Determination of impact resistance of paint film"; thickness is tested according to GB / T 13452.2-2008 "Determination of film thickness of paint and varnish"; hardness is tested according to GB / T 6739-2006 "Determination of film thickness by pencil method for paint and varnish"; bending test is carried out according to GB / T6742-2007 "Bending test for paint and varnish (cylindrical shaft)".

[0055] The clean coal tar mixed phenol used in this embodiment is obtained by vacuum distillation of coal tar mixed phenol obtained by thermal cracking of coal, wherein the conditions of the vacuum distillation are: pressure 0.07 MPa, temperature 120° C., and distillation time 2 h.

[0056] Example 1: Preparation of coal tar mixed phenolic novolac epoxy resin

[0057] The mass ratio of clean coal tar mixed phenol to dichloromethane is 1:0.2, and the mass ratio of clean coal tar mixed phenol to oxalic acid is 1:0.01. Place in a reactor, stir evenly under the protection of inert gas, add (37%wt) formaldehyde solution (the mass ratio of clean coal tar mixed phenol to formaldehyde is 1:0.2) at a rate of 0.3mL / min, and react at 90℃ for 6h. After removing water from the product, vacuum dry at 70℃ for 6h to obtain phenolic resin.

[0058] Add dried phenolic resin, epichlorohydrin in a molar amount of 4 times that of clean coal tar mixed phenol, and benzyltriethylammonium chloride in a molar amount of 1% of the clean coal tar mixed phenol into a reactor, stir at 80°C for 2 hours, reduce the temperature to 70°C, slowly add 40% sodium hydroxide solution at a rate of 0.2 mL / min, raise the temperature to 85°C, continue the reaction for 2 hours, and naturally cool the reaction liquid; remove excess epichlorohydrin and water in the above reaction liquid by vacuum distillation, add 20% by mass toluene to the residue for dilution, remove the by-product NaCl solid by suction filtration, and evaporate the toluene from the liquid by vacuum distillation to obtain a pure coal tar mixed phenol-based epoxy resin.

[0059] The structure and epoxy value of the coal tar mixed phenolic novolac epoxy resin prepared in this example are as follows:

[0060] from Figure 1 It can be seen that PR linear phenolic resin: 3335cm -1 is the stretching vibration peak of phenolic hydroxyl group, 2045cm -1 Aromatic CH stretching vibration peak, 2927cm -1 、2862cm -1 The peak of aliphatic CH stretching vibration is 1706 cm -1 is the stretching vibration peak of C=O, 1597cm -1 、1500cm -1 、1472cm -1 The C=C stretching vibration peak in the aromatic ring is the skeleton vibration of the benzene ring, 1363cm -1 It is the deformation vibration peak of -CH3 and -CH2, 1232cm -1 The stretching vibration peak of the aromatic ring CO (phenol), 1108 cm -1 CO stretching vibration in -CH2OH, 813 cm -1 、754cm -1 、691cm -1 It is the peak of ortho- and meta-substituted benzene ring. PER phenolic epoxy resin: 3441cm -1 is the stretching vibration peak of phenolic hydroxyl group, 2927cm -1 、2875cm -1 It is the aliphatic CH stretching vibration peak, 1599cm -1 、1496cm -1 The C=C stretching vibration peak in the aromatic ring is the skeleton vibration of the benzene ring, 1736cm -1 is the stretching vibration peak of C=O, 1457cm -1 The methylene peak (-CH2) between benzene rings is 1245 cm -1 The CO stretching vibration peak of the aromatic ring is 1042 cm -1COC stretching vibration peak (ether), 913 cm -1 、842cm -1 The characteristic absorption peak of epoxy group is 755cm -1 is the peak of ortho-substitution of benzene ring. Figure 1 It can be seen that the stretching vibration peak intensity of phenolic hydroxyl group is significantly weakened, and the phenolic epoxy resin appears at 913 cm -1 The characteristic peak of epoxy group indicates that the hydroxyl group was successfully epoxidized and the epoxy group was introduced.

[0061] from Figure 2 It can be seen that the absorption peaks of the synthesized coal tar mixed phenolic novolac epoxy resin and the commercially available novolac epoxy resin are roughly similar, both of which have the 913cm -1 、840cm -1 Wavenumber characteristic absorption peak.

[0062] from Figure 3 It can be seen that 1 HNMR (CDCl3-d6, ppmδ): 6.55-7.29 (benzene ring), 3.30 (-CH- in epoxy group), 2.70-2.90 (-CH2- connected to benzene ring), 3.90-4.20 (-CH2- in epoxy group), indicating that the phenolic epoxy resin has been successfully prepared.

[0063] Epoxy value: 0.4561.

[0064] Example 2: Application of coal tar mixed phenolic novolac epoxy resin.

[0065] The phenolic epoxy resin prepared in Example 1 is mixed with the 2041 cardanol modified curing agent in a mixed diluent (xylene: n-butanol = 7:3), wherein the molar ratio of the epoxy group in the epoxy resin to the 2041 cardanol modified curing agent is 1:1 (the molar ratio of the epoxy resin to the 2041 cardanol modified curing agent is 1:1.5). After stirring and mixing evenly, the obtained mixture is applied, degassed in a vacuum oven for 1 hour, and finally cured at room temperature for 48 hours or at 80-100°C for 3 hours.

[0066] Comparative Example 1

[0067] F-type phenolic epoxy resin (Y44-80, commercially available) was used as a comparative example, and the Y44-80 phenolic epoxy resin was cured. The curing agent used for the curing and the specific curing conditions were consistent with the conditions for curing the phenolic epoxy resin in Example 2.

[0068] The actual picture of the coating obtained after curing the coal tar mixed phenolic novolac epoxy resin prepolymer prepared in Example 1 of the present invention and the commercially available Y44-80 novolac epoxy resin is as follows: Figure 4 shown.

[0069] Coating samples were prepared using the anti-corrosion coatings prepared in Example 1 and Comparative Example 1, and their main properties were tested. The results are shown in Table 1.

[0070] The adhesion test graph of the coating obtained after curing the coal tar mixed phenolic epoxy resin prepolymer prepared in Example 1 of the present invention and the commercially available Y44-80 phenolic epoxy resin is as follows: Figure 5 shown.

[0071] The impact resistance test graph of the coating obtained after curing the coal tar mixed phenolic epoxy resin prepolymer prepared in Example 1 of the present invention and the commercially available Y44-80 phenolic epoxy resin is as follows: Figure 6 shown.

[0072] The bending resistance test graph of the coating obtained after curing the coal tar mixed phenolic epoxy resin prepolymer prepared in Example 1 of the present invention and the commercially available Y44-80 phenolic epoxy resin is as follows: Figure 7 shown.

[0073] Table 1 Properties of phenolic epoxy resin-2041 varnish coating

[0074]

[0075] It can be seen from Table 1 that, when the paint film thickness is basically the same, the coating sample corresponding to Example 1 has better flexibility and impact resistance.

[0076] It is shown that the coal tar-based epoxy resin of the present application can overcome the shortcomings of ordinary phenolic epoxy anti-corrosion coatings in terms of brittleness, flexibility, impact resistance, etc., improve the anti-corrosion performance of the coating, and expand the application field of epoxy resin.

Claims

1. A method for preparing a coal tar mixed phenolic novolac epoxy resin, comprising the following steps: S1. In an inert atmosphere, clean coal tar mixed phenol, a solvent and an acid catalyst are mixed and stirred, and then an aldehyde solution is added to react to obtain a phenolic resin; S2. Under an inert atmosphere, the phenolic resin, phase transfer catalyst and epichlorohydrin are mixed and stirred, preheated to 70-100°C, reacted for 1-4 hours, cooled to 65-70°C, added with an alkaline catalyst, heated to 80-85°C, continued to react for 2-3 hours, and cooled naturally; the coal tar mixed phenol-based phenolic epoxy resin is obtained through post-treatment.

2. The preparation method according to claim 1, characterized in that: In step S1, the mass ratio of the clean coal tar mixed phenol to the aldehyde is 1:0.6-0.9; The mass ratio of the clean coal tar mixed phenol to the solvent is 1:0.1-0.5; The mass ratio of the clean coal tar mixed phenol to the acid catalyst is 1:0.01-0.

2.

3. The preparation method according to claim 1 or 2, characterized in that: In step S1, the solvent is acetone or dichloromethane; The acid catalyst is sulfuric acid, hydrochloric acid, oxalic acid or p-toluenesulfonic acid; The aldehydes are formaldehyde, furfural, benzaldehyde or butyraldehyde.

4. The preparation method according to any one of claims 1 to 3, characterized in that: In step S1, the reaction temperature is 60-110°C and the reaction time is 1.5-8h; After the reaction is completed, the phenolic resin is obtained by natural cooling, removing water and vacuum drying.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In step S2, the alkaline catalyst is a sodium hydroxide aqueous solution with a concentration of 30-40%, and the molar amount of sodium hydroxide is 20-25% of the epichlorohydrin; The dropping speed of the alkaline catalyst is 0.2-0.3 mL / min.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step S2, the post-processing includes the following steps: The excess epichlorohydrin and water in the reaction system are removed by distillation under reduced pressure, and then 15-25% by mass of toluene is added for dilution to remove the byproduct NaCl and catalyst NaOH solid, and then the toluene is removed by distillation under reduced pressure.

7. The coal tar mixed phenolic novolac epoxy resin prepared by the method according to any one of claims 1 to 6.

8. A coal tar mixed phenolic novolac epoxy resin coating, made from component A and component B; The component A comprises the coal tar mixed phenolic novolac epoxy resin as claimed in claim 7 and solvent A; The component B comprises an epoxy resin curing agent and a solvent B; The molar ratio of the epoxy groups in the coal tar mixed phenol novolac epoxy resin to the epoxy resin curing agent is 1:1 to 1.

5.

9. The coal tar mixed phenolic novolac epoxy resin coating according to claim 8, characterized in that: The mass parts of the component A are as follows: 80-100 parts of coal tar mixed phenol-based epoxy resin, 15-20 parts of solvent A; The mass parts of the component B are as follows: 80-100 parts of epoxy resin curing agent, 20-30 parts of solvent B; The solvent A and the solvent B are at least one of toluene, benzene, xylene, ethylbenzene, acetone, butanone, benzyl alcohol, n-butanol or a mixture of two of these solvents; The epoxy resin curing agent is at least one of 2041 cardanol modified curing agent, T-31 phenol amine curing agent, polyether amine and diaminodiphenyl sulfone.

10. The method for preparing the coal tar mixed phenolic novolac epoxy resin coating according to claim 8 or 9, comprising the following steps: The component A is mixed with the component B, and the obtained mixture is vacuum degassed and then pre-cured and cured in sequence to obtain the product. The degassing time is 0.5 to 1 hour; The pre-curing temperature is 60-100°C and the time is 1-2h; The curing includes low temperature curing and high temperature curing performed sequentially; The low-temperature curing temperature is room temperature and the time is 40 to 60 hours, and the high-temperature curing temperature is 60 to 100° C. and the time is 1 to 3 hours.

Images