A polyphenol oxide coating, its preparation method and application

Abstract

The present invention relates to a polyphenol oxide coating and its preparation method and application. The coating is composed of a high molecular weight polyphenol oxide resin and a low molecular weight thermosetting epoxy resin as film-forming substances, a compound organic reagent as a solvent, and an organosilicon defoamer and a leveling agent added in combination. The preparation method of the coating is as follows: dissolve the high molecular weight polyphenol oxide resin and the low molecular weight epoxy resin in a high boiling point organic solvent, and heat and dissolve to obtain a liquid resin A; add the organosilicon defoamer, the leveling agent and the curing agent to a low boiling point organic solvent, and stir and mix evenly at room temperature to obtain a functional diluent B, and mix the liquid resin A and the functional diluent B in a certain proportion to obtain the coating. The coating has excellent spraying processability and fast surface drying characteristics. The coating formed thereby has a low surface roughness, high adhesion, excellent heat resistance, and excellent broadband wave-transmitting performance, and is suitable for the surface modification of fiber-reinforced resin-based wave-transmitting composites and radomes.

Description

Technical Field

[0001] The present invention belongs to the technical fields of materials and coatings, and particularly relates to a polyphenol oxide coating and a preparation method and application thereof. Background Art

[0002] Fiber-reinforced resin-based wave-transparent composites have excellent broadband wave-transparent properties, high specific strength, and specific modulus, and are important materials for preparing high-performance radomes, and are widely used in high-end equipment such as aviation, aerospace, and shipborne vessels. To improve the stealth performance of the radome, it is necessary to construct microstructures with electromagnetic resonance characteristics on the surface of the composite material. However, the surface of the original fiber-reinforced resin-based composite material usually contains a large number of micropores, fiber weaving patterns, and unevenly distributed resin matrixes. These structures result in high surface roughness and poor surface uniformity of the original composite material, affecting the construction accuracy of subsequent electromagnetic functional structures. Therefore, it is necessary to repair the surface defects of the fiber-reinforced resin-based composite material.

[0003] A common means of repairing the surface defects of composite materials is to construct a coating. Currently, the commonly used coating system is composed of a polymer as the binder phase and specific pigments and fillers added. Although such coatings can repair the surface defects of composite materials and endow the composite materials with specific functions (such as corrosion resistance, wear resistance, oxidation resistance, rain erosion resistance, etc.), due to the presence of pigments and fillers, the dielectric constant and dielectric loss of such coatings are generally large, and using them to modify composite materials usually reduces the wave-transparent performance of the composite materials. Summary of the Invention

[0004] To solve the problems existing in the prior art, the present invention provides a polyphenol oxide coating suitable for surface modification of fiber-reinforced resin-based wave-transparent composites and a preparation method thereof.

[0005] The technical solution adopted by the present invention is as follows:

[0006] In the first aspect, the present invention provides a polyphenol oxide coating, which is composed of a high molecular weight polyphenol oxide resin and a low molecular weight thermosetting epoxy resin as film-forming substances, a compound organic reagent as a solvent, and an organosilicon defoaming agent and an organosilicon leveling agent added.

[0007] In the second aspect, the present invention provides a preparation method of a polyphenol oxide coating, including the following steps:

[0008] Dissolve the high molecular weight polyphenol oxide resin and the low molecular weight thermosetting epoxy resin in a high boiling point organic solvent, and heat and dissolve to obtain a liquid resin A;

[0009] Add the organosilicon defoaming agent, the organosilicon leveling agent, and the curing agent to a low boiling point organic solvent, and stir and mix evenly at room temperature to obtain a functional diluent B;

[0010] Mix the liquid resin A and the functional diluent B in a certain proportion to obtain a polyphenol oxide coating.

[0011] Furthermore, the molecular weight of the high molecular weight polyphenol oxide resin is 30,000 - 60,000; the epoxy value of the low molecular weight thermosetting epoxy resin is 0.2 - 0.6; the mass of the low molecular weight thermosetting epoxy resin is 0.2 - 0.5 times the mass of the high molecular weight polyphenol oxide resin.

[0012] Furthermore, the high boiling point organic solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, N-methylpyrrolidone, and m-cresol.

[0013] Furthermore, the mass ratio of the sum of the masses of the high molecular weight polyphenol oxide resin and the low molecular weight thermosetting epoxy resin to the mass of the high boiling point organic solvent is 1:1 - 1.5.

[0014] Furthermore, the liquid resin A is obtained by heating and dissolving, where the heating temperature is 60 - 80 °C.

[0015] Furthermore, the low boiling point organic solvent is at least one of ethyl acetate, acetone, methyl ethyl ketone, and tetrahydrofuran. The mass ratio of the silicone defoamer, silicone leveling agent, epoxy resin curing agent, and low boiling point organic solvent is: (0.5 - 1):(0.5 - 1):(2 - 4):100.

[0016] Furthermore, the mass ratio of the liquid resin A to the functional diluent B is 1:(2.5 - 3).

[0017] In a third aspect, the present invention provides the application of the above polyphenol oxide coating in the surface modification of resin-based wave-transparent composites.

[0018] Furthermore, the application is specifically: spraying the coating on the surface of the resin-based wave-transparent composite material, and performing high-temperature curing to complete the surface modification of the composite material, improving the surface uniformity and denseness of the composite material, and reducing the surface roughness of the composite material.

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

[0020] The polyphenol oxide coating of the present invention has excellent spraying process performance and fast surface drying characteristics, can achieve rapid repeated spraying, increase the spraying thickness, and the coating has excellent properties such as low surface roughness, high adhesion, good solvent resistance, and excellent heat resistance, and also has excellent broadband wave-transparent performance, can be applied to the surface modification of fiber-reinforced resin-based wave-transparent composites and radomes, and the composite material modified with it has excellent wave-transparent performance. Description of the Drawings

[0021] Figure 1 It is the broadband wave transmission curve of the composite material flat plate before and after coating construction tested by the focusing method in Example 1.

[0022] Figure 2 It is the three-dimensional surface profile of the composite material before and after coating construction tested by a white light interferometer in Example 1.

[0023] Figure 3 It is the broadband wave transmission curve of the composite material flat plate before and after coating construction tested by the focusing method in Example 2.

[0024] Figure 4 It is the three-dimensional surface profile of the composite material before and after coating construction tested by a white light interferometer in Example 2.

[0025] Figure 5 It is the broadband wave transmission curve of the composite material flat plate before and after coating construction tested by the focusing method in Example 3.

[0026] Figure 6 It is the three-dimensional surface profile of the composite material before and after coating construction tested by a white light interferometer in Example 3. Detailed implementation manners

[0027] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below through specific examples and drawings.

[0028] The present invention relates to a polyphenol oxime coating, which is composed of a high molecular weight polyphenol oxime resin and a low molecular weight thermosetting epoxy resin as film-forming substances, a compound organic reagent as a solvent, and an organosilicon defoaming agent and an organosilicon leveling agent are added and compounded.

[0029] The present invention discloses a preparation method of a polyphenol oxime coating, and the preparation method of the polyphenol oxime coating specifically includes the following steps:

[0030] 1. Dissolve a certain amount of high molecular weight polyphenol oxime resin and low molecular weight thermosetting epoxy resin in a high boiling point organic solvent, and heat and dissolve to obtain liquid resin A.

[0031] 2. Add an organosilicon defoaming agent, an organosilicon leveling agent, and an epoxy resin curing agent to a low boiling point organic solvent, and stir and mix evenly at room temperature to obtain a functional diluent B.

[0032] 3. Mix the liquid resin A and the functional diluent B in a certain proportion to obtain the coating.

[0033] In step 1, the molecular weight of the polyphenol oxime resin is 30,000 to 60,000.

[0034] The epoxy value of the low molecular weight thermosetting epoxy resin in step 1 is 0.2 to 0.6.

[0035] The mass of the low molecular weight thermosetting epoxy resin in step 1 is 0.2 to 0.5 times the mass of the polyphenylene oxide resin in step 1.

[0036] The high boiling point organic solvent in step 1 is any one or any mixture of any proportions of N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, N-methylpyrrolidone, m-cresol;

[0037] The mass ratio of the sum of the masses of the polyphenylene oxide resin and the low molecular weight thermosetting epoxy resin in step 1 to the high boiling point organic solvent is 1:1 to 1.5.

[0038] The heating temperature in step 1 is 60 to 80 °C.

[0039] The epoxy resin curing agent in step 2 is a general epoxy resin curing agent, including but not limited to aliphatic amines, aromatic amines, polyamides, imidazoles, polyureas, acid anhydrides, etc.

[0040] The low boiling point organic solvent in step 2 is any one or any mixture of any proportions of ethyl acetate, acetone, methyl ethyl ketone, tetrahydrofuran.

[0041] The mass ratio of the silicone defoamer, silicone leveling agent, epoxy resin curing agent, and low boiling point organic solvent in step 2 is: (0.5 to 1):(0.5 to 1):(2 to 4):100.

[0042] The mass ratio of the liquid resin A to the functional diluent B in step 3 is 1:(2.5 to 3).

[0043] The present invention discloses a use of the coating, specifically spraying the coating on the surface of a resin matrix wave-transparent composite material, and performing high-temperature curing to complete the surface modification of the composite material, improving the surface uniformity and density of the composite material, and reducing the surface roughness of the composite material.

[0044] The number of spraying passes is 10.

[0045] Before spraying, the surface of the composite material needs to be polished, specifically by polishing with 200-mesh to 600-mesh sandpaper to remove surface impurities and improve the spraying effect of the coating and the adhesion of the coating.

[0046] The resin matrix wave-transparent composite material includes but not limited to quartz fiber reinforced cyanate ester composite material, quartz fiber reinforced epoxy resin composite material, quartz fiber reinforced bismaleimide composite material, quartz fiber reinforced polyester composite material, quartz fiber reinforced phenolic composite material, etc.

[0047] The curing temperature is 80 to 120 °C, and the curing time is 2 to 8 hours.

[0048] Example 1

[0049] Weigh 20 g of polyphenylene oxide resin and 4 g of E51 epoxy resin and add them to 24 g of N,N-dimethylacetamide solvent. Stir at 60 °C until the resin is completely dissolved to obtain liquid resin A. Then, weigh 0.5 g of silicone defoamer, 0.5 g of silicone leveling agent, and 2 g of triethylenetetramine (epoxy curing agent) and dissolve them in 100 g of ethyl acetate to obtain functional diluent B. Finally, weigh 40 g of liquid resin A and 100 g of functional diluent B and mix and stir them evenly to obtain the coating.

[0050] Use 200-mesh sandpaper to polish the surface of the quartz fiber-reinforced cyanate ester composite material. Spray the coating on the polished composite material for a total of 10 times. After spraying, place it in an 80 °C oven and cure for 12 hours to complete the construction of the composite material surface coating. The surface drying time after single spraying of the coating is listed in Table 1. The adhesion of the coating was tested by the cross-cut test method according to the national standard (GB / T 9286-1998) and reached grade 0. The heat resistance of the coating was tested using a thermogravimetric analyzer, and the 5% weight loss temperature is listed in Table 1. The broadband wave transmission curves of the composite material flat plate before and after coating construction were tested by the focusing method, and the results are as Figure 1 shown. The wave transmission performance of the composite material after coating construction has not decreased. The three-dimensional surface profile morphology of the composite material before and after coating construction was tested using a white light interferometer, and the results are as Figure 2 shown. It can be seen that the surface uniformity and density of the composite material after coating construction have increased, and the roughness has decreased.

[0051] Example 2

[0052] Take 20 g of polyphenylene oxide resin and 10 g of E51 epoxy resin and add them to 30 g of N,N-dimethylformamide solvent. Stir at 60 °C until the resin is completely dissolved to obtain liquid resin A. Then, weigh 0.5 g of silicone defoamer, 0.5 g of silicone leveling agent, and 4 g of 2-ethyl-4-methylimidazole (epoxy curing agent) and dissolve them in 100 g of acetone to obtain functional diluent B. Finally, weigh 40 g of liquid resin A and 100 g of functional diluent B and mix and stir them evenly to obtain the coating.

[0053] The surface of the quartz fiber reinforced cyanate ester composite material was polished with 400-mesh sandpaper, and the coating was sprayed on the polished composite material for a total of 10 times. After spraying, it was placed in an oven at 120 °C for curing for 2 hours to complete the construction of the surface coating of the composite material. The surface drying time after single spraying of the coating is listed in Table 1. The adhesion of the coating was tested by the cross-cut test method according to the national standard (GB / T 9286-1998) and reached level 0. The heat resistance of the coating was tested by a thermogravimetric analyzer, and the 5% weight loss temperature is listed in Table 1. The broadband wave-transmitting curves of the composite material flat plate before and after coating construction were tested by the focusing method, and the results are as Figure 3 shown. After coating construction, the wave-transmitting performance of the composite material did not decrease. The three-dimensional surface profile morphology of the composite material before and after coating construction was tested by a white light interferometer, and the results are as Figure 4 shown. It can be seen that after coating construction, the surface uniformity and compactness of the composite material are improved, and the roughness is reduced.

[0054] Example 3

[0055] 20 g of polyphenylene oxide resin and 4 g of E51 epoxy resin were added to 36 g of N-methylpyrrolidone solvent, and stirred at 60 °C until the resin was completely dissolved to obtain liquid resin A. Then, 1 g of silicone defoamer, 1 g of silicone leveling agent, and 4 g of m-phenylenediamine (epoxy curing agent) were weighed in turn and dissolved in 100 g of tetrahydrofuran to obtain functional diluent B. Finally, 30 g of liquid resin A and 90 g of functional diluent B were mixed and stirred evenly to obtain the coating.

[0056] The surface of the quartz fiber reinforced cyanate ester composite material was polished with 600-mesh sandpaper, and the coating was sprayed on the polished composite material for a total of 10 times. After spraying, it was placed in an oven at 120 °C for curing for 4 hours to complete the construction of the surface coating of the composite material. The surface drying time after single spraying of the coating is listed in Table 1. The adhesion of the coating was tested by the cross-cut test method according to the national standard (GB / T 9286-1998) and reached level 0. The heat resistance of the coating was tested by a thermogravimetric analyzer, and the 5% weight loss temperature is listed in Table 1. The broadband wave-transmitting curves of the composite material flat plate before and after coating construction were tested by the focusing method, and the results are as Figure 5 shown. After coating construction, the wave-transmitting performance of the composite material did not decrease. The three-dimensional surface profile morphology of the composite material before and after coating construction was tested by a white light interferometer, and the results are as Figure 6 shown. It can be seen that after coating construction, the surface uniformity and compactness of the composite material are improved, and the roughness is reduced.

[0057] Table 1

[0058]

[0059] The specific embodiments of the present invention disclosed above are intended to help understand the content of the present invention and implement it accordingly. Those of ordinary skill in the art can understand that various substitutions, changes, and modifications are possible without departing from the spirit and scope of the present invention. The present invention should not be limited to the content disclosed in the embodiments of this specification, and the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. Application of polyphenol oxygen coating in surface modification of resin-based wave-transparent composite materials, characterized in that, spray the polyphenol oxygen coating on the surface of the resin-based wave-transparent composite material, and complete the surface modification of the composite material through high-temperature curing; The preparation method of the polyphenol oxygen coating includes the following steps: Dissolve high molecular weight polyphenol oxygen resin and low molecular weight thermosetting epoxy resin in a high boiling point organic solvent, and heat and dissolve to obtain liquid resin A; Add silicone defoamer, silicone leveling agent and curing agent to a low boiling point organic solvent, and stir and mix evenly at room temperature to obtain functional diluent B; Mix the liquid resin A and the functional diluent B in a certain proportion to obtain the polyphenol oxygen coating; The molecular weight of the high molecular weight polyphenol oxygen resin is 30,000 to 60,000; the epoxy value of the low molecular weight thermosetting epoxy resin is 0.2 to 0.6; the mass of the low molecular weight thermosetting epoxy resin is 0.2 to 0.5 times the mass of the high molecular weight polyphenol oxygen resin; The high boiling point organic solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, N-methylpyrrolidone, m-cresol; The low boiling point organic solvent is at least one of ethyl acetate, acetone, methyl ethyl ketone, tetrahydrofuran; The mass ratio of the liquid resin A to the functional diluent B is 1:(2.5 - 3).

2. The application according to claim 1, characterized in that, The mass ratio of the sum of the masses of the high molecular weight polyphenol oxygen resin and the low molecular weight thermosetting epoxy resin to the high boiling point organic solvent is 1:1 to 1.

5.

3. The application according to claim 1, characterized in that, When heating and dissolving to obtain liquid resin A, the heating temperature is 60 - 80 °C.

4. The application according to claim 1, characterized in that, The mass ratio of the silicone defoamer, silicone leveling agent, epoxy resin curing agent, and low boiling point organic solvent is: (0.5 - 1):(0.5 - 1):(2 - 4):100.

Images