A method for preparing modified phenolic resin coating

Abstract

The invention relates to the technical field of coatings, and discloses a method for preparing a modified phenolic resin coating, wherein the amino group in 3,3-dimethoxy-4,4-diaminobiphenyl reacts with CH3(CH2) n The carboxyl group in COOH undergoes an amidation reaction to obtain 3,3-dimethoxy-4,4-dialkylamide biphenyl, and the obtained product is demethoxylated under the catalysis of boron tribromide to obtain 4,4-dialkylamide biphenyl diphenol. Polyformaldehyde, phenol, 4,4-dialkylamide biphenyl diphenol, etc. are polymerized under alkaline conditions to obtain a modified phenolic resin. Finally, a leveling agent, hydroxyethyl cellulose, an emulsifier, etc. are added to the modified phenolic resin for high-speed dispersion to obtain a modified phenolic resin coating. The phenolic resin coating prepared by the present invention has excellent mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a method for preparing a modified phenolic resin coating. Background Art

[0002] With the rapid development of industry and agriculture in my country, various materials have been widely developed. However, since they are easily corroded and damaged by rain, air, etc., the maintenance cost is high. Therefore, covering the compliant materials with a layer of coating is a current research hotspot.

[0003] Phenolic resin is a synthetic resin formed by the polycondensation of phenol and formaldehyde. It has a history of more than 100 years. The production cost of phenolic resin is low and the raw materials are easy to obtain. The prepared phenolic resin has good mechanical properties, dimensional stability, cold and heat resistance, flame retardancy and other properties. Due to these excellent properties, phenolic resin is widely used in construction, coatings, abrasives, friction materials, fireworks and firecrackers and other fields.

[0004] Phenolic resin paint is a type of paint. Its coating film has excellent properties such as high hardness, chemical corrosion resistance, and insulation. It is now widely used in wood, furniture, construction and other fields. However, its coating film is relatively brittle. Therefore, the modification of phenolic resin in order to increase its toughness and other mechanical properties is one of the research hotspots. Summary of the invention

[0005] The technical problem solved by the present invention is: providing a method for preparing a modified phenolic resin coating, preparing a 4,4-dialkylamide biphenol containing a long alkyl chain, reacting the 4,4-dialkylamide biphenol with phenol or the like to obtain a phenolic resin coating containing a long chain, and the prepared coating has excellent mechanical properties.

[0006] The technical solution of the present invention is:

[0007] A method for preparing a modified phenolic resin coating, the preparation method comprising:

[0008] (1) Add paraformaldehyde and an aqueous solution of sodium hydroxide into a flask, then add phenol and 4,4-dialkylamide biphenol, raise the temperature to 80-90° C., react for 2-5 hours, and dry to obtain a modified phenolic resin.

[0009] (2) Add the modified phenolic resin to deionized water solvent to prepare a solution with a mass fraction of 35-50%, then add leveling agent HJ915, hydroxyethyl cellulose, emulsifier sodium dodecylbenzene sulfonate, and emulsifier Span-80, and disperse at high speed to obtain a modified phenolic resin coating.

[0010] Preferably, the ratio of each substance in step (1) is paraformaldehyde: sodium hydroxide: phenol: 4,4-dialkylamide biphenol = (1.5-1.8) mol: (0.04-0.05) mol: 1 mol: (0.1-0.3) mol.

[0011] Preferably, the ratio of each substance in step (2) is modified phenolic resin: leveling agent HJ915: hydroxyethyl cellulose: emulsifier sodium dodecylbenzene sulfonate: emulsifier Span-80 = 100g: (1-5)g: (0.2-0.5)g: (0.2-0.6)g: (0.1-0.3)g.

[0012] Preferably, the preparation method of 4,4-dialkylamide biphenol in step (1) is:

[0013] (3) 3,3-dimethoxy-4,4-diaminobiphenyl, CH3(CH2) n COOH was added into the pressure reactor, stirring was started, heating was performed for reaction, cooling was performed, the product was washed with petroleum ether, and recrystallized with dichloromethane to obtain 3,3-dimethoxy-4,4-dialkylamide biphenyl.

[0014] (4) Under nitrogen protection, 3,3-dimethoxy-4,4-dialkylamide biphenyl is dissolved in dichloromethane solvent, placed in an ice-water bath, stirred and dispersed for 5-15 minutes, and then boron tribromide is added thereto, and the reaction is continued for 20-50 minutes. Then, the mixture is moved to room temperature for reaction for 3-6 hours, and vacuum distilled, washed with ether, and recrystallized from dichloromethane to obtain 4,4-dialkylamide biphenyl diphenol.

[0015] Preferably, the ratio of each substance in step (3) is 3,3-dimethoxy-4,4-diaminobiphenyl: CH3(CH2) n COOH=1mol:(1-1.3)mol.

[0016] Preferably, the value of n in step (3) is 8-16.

[0017] Preferably, the heating reaction temperature in step (3) is 160-180° C. and the time is 5-10 h.

[0018] Preferably, the ratio of each substance in step (4) is 3,3-dimethoxy-4,4-dialkylamidebiphenyl:boron tribromide=1 mol:(2-2.5) mol.

[0019] The beneficial technical effects of the present invention are:

[0020] The amino group in 3,3-dimethoxy-4,4-diaminobiphenyl reacts with CH3(CH2) nThe carboxyl group in COOH undergoes an amidation reaction to obtain 3,3-dimethoxy-4,4-dialkylamide biphenyl, and the obtained product is demethoxylated under the catalysis of boron tribromide to obtain 4,4-dialkylamide biphenyl diphenol. Polyformaldehyde, phenol, 4,4-dialkylamide biphenyl diphenol, etc. are polymerized under alkaline conditions to obtain a modified phenolic resin. Finally, a leveling agent, hydroxyethyl cellulose, an emulsifier, etc. are added to the modified phenolic resin for high-speed dispersion to obtain a modified phenolic resin coating.

[0021] The 4,4-dialkylamide biphenol prepared by the present invention contains a flexible alkyl long chain, which is chemically connected with a phenol unit to form a component of a prepolymer. The prepared phenolic resin is a uniform interpenetrating cross-linked network structure, wherein the flexible alkyl long chain can play the role of an intramolecular plasticizer. Under the impact of external force, the flexible alkyl long chain contained in the three-dimensional network structure is horizontally mounted on the fracture surface, absorbs impact energy, prevents the expansion of cracks, and enhances the toughness and other mechanical properties of the phenolic resin. The phenolic resin coating prepared by the present invention has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a preparation route for 4,4-dialkylamide biphenol. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0024] Example 1

[0025] (1) 0.2 mol of 3,3-dimethoxy-4,4-diaminobiphenyl and 0.25 mol of CH3(CH2) 10 COOH was added to the pressure reactor, stirring was started, the reaction was heated to 170°C for 8 hours, and the reaction was cooled. The product was washed with petroleum ether and recrystallized from dichloromethane to obtain 3,3-dimethoxy-4,4-dialkylamide biphenyl.

[0026] (2) Under nitrogen protection, 0.3 mol of 3,3-dimethoxy-4,4-dialkylamide biphenyl was dissolved in dichloromethane solvent, stirred and dispersed in an ice-water bath for 10 minutes, and then 0.6 mol of boron tribromide was added thereto, and the reaction was continued for 30 minutes. Then, the mixture was moved to room temperature for 4 hours, and distilled under reduced pressure, washed with ether, and recrystallized from dichloromethane to obtain 4,4-dialkylamide biphenyl diphenol.

[0027] (3) 0.3 mol of polyformaldehyde and an aqueous solution containing 0.01 mol of sodium hydroxide are added to a flask, and then 0.2 mol of phenol and 0.04 mol of 4,4-dialkylamide biphenol are added thereto. The temperature is raised to 85° C. for reaction for 4 hours, and then dried to obtain a modified phenolic resin.

[0028] (4) 200 g of modified phenolic resin was added to deionized water solvent to prepare a solution with a mass fraction of 40%, and then 8 g of leveling agent HJ915, 10 g of hydroxyethyl cellulose, 1.2 g of emulsifier sodium dodecylbenzene sulfonate, and 0.4 g of emulsifier Span-80 were added and dispersed at high speed to obtain a modified phenolic resin coating.

[0029] Example 2

[0030] (1) 0.2 mol of 3,3-dimethoxy-4,4-diaminobiphenyl and 0.24 mol of CH3(CH2) 12 COOH was added to the pressure reactor, stirring was started, the reaction was heated to 180°C for 10 hours, and the reaction was cooled. The product was washed with petroleum ether and recrystallized from dichloromethane to obtain 3,3-dimethoxy-4,4-dialkylamide biphenyl.

[0031] (2) Under nitrogen protection, 0.3 mol of 3,3-dimethoxy-4,4-dialkylamide biphenyl was dissolved in dichloromethane solvent, stirred and dispersed in an ice-water bath for 15 minutes, and then 0.6 mol of boron tribromide was added thereto, and the reaction was continued for 50 minutes. Then, the mixture was moved to room temperature for reaction for 5 hours, and vacuum distilled, washed with ether, and recrystallized from dichloromethane to obtain 4,4-dialkylamide biphenyl diphenol.

[0032] (3) 0.32 mol of polyformaldehyde and an aqueous solution containing 0.009 mol of sodium hydroxide are added to a flask, and then 0.2 mol of phenol and 0.05 mol of 4,4-dialkylamide biphenol are added thereto. The temperature is raised to 85° C. for reaction for 5 h, and then dried to obtain a modified phenolic resin.

[0033] (4) 200 g of modified phenolic resin was added to deionized water solvent to prepare a solution with a mass fraction of 50%, and then 8 g of leveling agent HJ915, 25 g of hydroxyethyl cellulose, 0.8 g of emulsifier sodium dodecylbenzene sulfonate, and 0.4 g of emulsifier Span-80 were added and dispersed at high speed to obtain a modified phenolic resin coating.

[0034] Example 3

[0035] (1) 0.2 mol of 3,3-dimethoxy-4,4-diaminobiphenyl and 0.24 mol of CH3(CH2) 14COOH was added to the pressure reactor, stirring was started, the reaction was heated to 180°C for 8 hours, and the reaction was cooled. The product was washed with petroleum ether and recrystallized from dichloromethane to obtain 3,3-dimethoxy-4,4-dialkylamide biphenyl.

[0036] (2) Under nitrogen protection, 0.3 mol of 3,3-dimethoxy-4,4-dialkylamide biphenyl was dissolved in dichloromethane solvent, stirred and dispersed in an ice-water bath for 10 minutes, and then 0.7 mol of boron tribromide was added thereto, and the reaction was continued for 50 minutes. Then, the mixture was moved to room temperature for 4 hours, and distilled under reduced pressure, washed with ether, and recrystallized from dichloromethane to obtain 4,4-dialkylamide biphenyl diphenol.

[0037] (3) 0.32 mol of polyformaldehyde and an aqueous solution containing 0.01 mol of sodium hydroxide are added to a flask, and then 0.2 mol of phenol and 0.02 mol of 4,4-dialkylamide biphenol are added thereto. The temperature is raised to 90° C. for reaction for 4 hours, and then dried to obtain a modified phenolic resin.

[0038] (4) 200 g of modified phenolic resin was added to deionized water solvent to prepare a solution with a mass fraction of 40%, and then 10 g of leveling agent HJ915, 10 g of hydroxyethyl cellulose, 0.5 g of emulsifier sodium dodecylbenzene sulfonate, and 0.4 g of emulsifier Span-80 were added and dispersed at high speed to obtain a modified phenolic resin coating.

[0039] Example 4

[0040] (1) 0.2 mol of 3,3-dimethoxy-4,4-diaminobiphenyl and 0.26 mol of CH3(CH2) 16 COOH was added to the pressure reactor, stirring was started, the reaction was heated to 160°C for 8 hours, and the reaction was cooled. The product was washed with petroleum ether and recrystallized from dichloromethane to obtain 3,3-dimethoxy-4,4-dialkylamide biphenyl.

[0041] (2) Under nitrogen protection, 0.3 mol of 3,3-dimethoxy-4,4-dialkylamide biphenyl was dissolved in dichloromethane solvent, stirred and dispersed in an ice-water bath for 15 minutes, and then 0.75 mol of boron tribromide was added thereto, and the reaction was continued for 40 minutes. Then, the mixture was moved to room temperature and reacted for 4 hours. The mixture was distilled under reduced pressure, washed with ether, and recrystallized from dichloromethane to obtain 4,4-dialkylamide biphenyl diphenol.

[0042] (3) 0.36 mol of polyformaldehyde and an aqueous solution containing 0.01 mol of sodium hydroxide are added to a flask, and then 0.2 mol of phenol and 0.04 mol of 4,4-dialkylamide biphenol are added thereto. The temperature is raised to 90° C. and reacted for 2 h. The mixture is dried to obtain a modified phenolic resin.

[0043] (4) 200 g of modified phenolic resin was added to deionized water solvent to prepare a solution with a mass fraction of 35%, and then 8 g of leveling agent HJ915, 20 g of hydroxyethyl cellulose, 1 g of emulsifier sodium dodecylbenzene sulfonate, and 0.3 g of emulsifier Span-80 were added and dispersed at high speed to obtain a modified phenolic resin coating.

[0044] Example 5

[0045] (1) 0.2 mol of 3,3-dimethoxy-4,4-diaminobiphenyl and 0.26 mol of CH3(CH2) 18 COOH was added to the pressure reactor, stirring was started, the reaction was heated to 180°C for 10 hours, and the reaction was cooled. The product was washed with petroleum ether and recrystallized from dichloromethane to obtain 3,3-dimethoxy-4,4-dialkylamide biphenyl.

[0046] (2) Under nitrogen protection, 0.3 mol of 3,3-dimethoxy-4,4-dialkylamide biphenyl was dissolved in dichloromethane solvent, stirred and dispersed in an ice-water bath for 10 minutes, and then 0.6 mol of boron tribromide was added thereto, and the reaction was continued for 50 minutes. Then, the mixture was moved to room temperature for 4 hours, and distilled under reduced pressure, washed with ether, and recrystallized from dichloromethane to obtain 4,4-dialkylamide biphenyl diphenol.

[0047] (3) 0.36 mol of polyformaldehyde and an aqueous solution containing 0.01 mol of sodium hydroxide are added to a flask, and then 0.2 mol of phenol and 0.06 mol of 4,4-dialkylamide biphenol are added thereto. The temperature is raised to 80° C. and reacted for 5 h. The mixture is dried to obtain a modified phenolic resin.

[0048] (4) 200 g of modified phenolic resin was added to deionized water solvent to prepare a solution with a mass fraction of 40%, and then 9 g of leveling agent HJ915, 30 g of hydroxyethyl cellulose, 1.2 g of emulsifier sodium dodecylbenzene sulfonate, and 0.2 g of emulsifier Span-80 were added and dispersed at high speed to obtain a modified phenolic resin coating.

[0049] Comparative Example 1

[0050] (1) 0.3 mol of paraformaldehyde and an aqueous solution containing 0.01 mol of sodium hydroxide are added to a flask, and then 0.2 mol of phenol is added thereto. The temperature is raised to 85° C. for reaction for 4 h, and then dried to obtain a phenolic resin.

[0051] (2) 200 g of phenolic resin was added to deionized water solvent to prepare a solution with a mass fraction of 40%, and then 8 g of leveling agent HJ915, 10 g of hydroxyethyl cellulose, 1.2 g of emulsifier sodium dodecylbenzene sulfonate, and 0.4 g of emulsifier Span-80 were added and dispersed at high speed to obtain a phenolic resin coating.

[0052] The phenolic resin coating was vacuum degassed, a 50% ethylene glycol solution of p-toluenesulfonic acid was added thereto, injected into a mold, and placed in a constant temperature curing box at 80° C. for curing to obtain a phenolic resin coating film.

[0053] The hardness of the phenolic resin coating was tested using a hardness tester.

[0054] The impact resistance of phenolic resin coating was tested using an impactor.

[0055] The notched impact strength of the phenolic resin coating was tested using a notched impact tester.

[0056] The shear strength of the phenolic resin coating was tested using an electronic material testing machine.

[0057]

[0058] The mechanical properties of Examples 1-5 are better than those of Comparative Example 1, because Examples 1-5 contain 4,4-dialkylamide biphenol, which contains flexible alkyl long chains, and the phenolic resin prepared by reacting it with phenol or the like is a cross-linked network structure, in which the flexible alkyl long chains can act as intramolecular plasticizers. Under the impact of external forces, the flexible alkyl long chains contained in the three-dimensional network structure cross the fracture surface, absorb impact energy, prevent the expansion of cracks, and enhance the toughness and other mechanical properties of the phenolic resin. Comparative Example 1 does not have flexible alkyl long chains, so its mechanical properties are poor.

[0059] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A method for preparing a modified phenolic resin coating, characterized in that: The preparation method is: (1) Adding an aqueous solution of paraformaldehyde and sodium hydroxide into a flask, and then adding phenol and 4,4-dialkylamide biphenol, heating to 80-90° C. to react for 2-5 hours, and drying to obtain a modified phenolic resin; (2) Adding the modified phenolic resin to a deionized water solvent to prepare a solution with a mass fraction of 35-50%, then adding a leveling agent HJ915, hydroxyethyl cellulose, an emulsifier sodium dodecylbenzene sulfonate, and an emulsifier Span-80, and dispersing at high speed to obtain a modified phenolic resin coating; The preparation method of 4,4-dialkylamide biphenol in step (1) is: (3) Add 3,3-dimethoxy-4,4-diaminobiphenyl and CH3(CH2)nCOOH into a pressure reactor, start stirring, heat the reaction, cool, wash the product with petroleum ether, and recrystallize from dichloromethane to obtain 3,3-dimethoxy-4,4-dialkylamidebiphenyl; (4) Under nitrogen protection, 3,3-dimethoxy-4,4-dialkylamide biphenyl is dissolved in dichloromethane solvent, placed in an ice-water bath, stirred and dispersed for 5-15 minutes, and then boron tribromide is added thereto, and the reaction is continued for 20-50 minutes, and then the mixture is moved to room temperature for reaction for 3-6 hours, and then vacuum distilled, washed with ether, and recrystallized from dichloromethane to obtain 4,4-dialkylamide biphenyl diphenol; the structural formula of the 4,4-dialkylamide biphenyl diphenol is ; In the step (3), the value of n is 8-16.

2. The method for preparing a modified phenolic resin coating according to claim 1, wherein: The ratio of each substance in step (1) is paraformaldehyde: sodium hydroxide: phenol: 4,4-dialkylamide biphenol = (1.5-1.8) mol: (0.04-0.05) mol: 1 mol: (0.1-0.3) mol.

3. The method for preparing the modified phenolic resin coating according to claim 1, characterized in that: The ratio of each substance in step (2) is modified phenolic resin: leveling agent HJ915: hydroxyethyl cellulose: emulsifier sodium dodecylbenzene sulfonate: emulsifier Span-80 = 100g: (1-5)g: (0.2-0.5)g: (0.2-0.6)g: (0.1-0.3)g.

4. The method for preparing a modified phenolic resin coating according to claim 1, wherein: The ratio of each substance in step (3) is 3,3-dimethoxy-4,4-diaminobiphenyl:CH3(CH2)nCOOH=1 mol:(1-1.3) mol.

5. The method for preparing the modified phenolic resin coating according to claim 1, characterized in that: The heating reaction temperature in step (3) is 160-180° C. and the time is 5-10 hours.

6. The method for preparing the modified phenolic resin coating according to claim 1, characterized in that: The ratio of each substance in step (4) is 3,3-dimethoxy-4,4-dialkylamide biphenyl: boron tribromide = 1 mol: (2-2.5) mol.

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