Hard felt coating and its preparation method, and carbon fiber hard felt and its preparation method

Abstract

The present invention discloses a hard felt coating, a preparation method thereof, a carbon fiber hard felt and a preparation method thereof, relating to the field of coatings. The hard felt coating is made of 20-25 wt% furan resin, 5-8 wt% modified phenolic resin, 5-8 wt% inorganic silicon hardening resin, 1-2 wt% emulsifying thickener, 18-26 wt% filler, 2-3 wt% film-forming auxiliary and 30-49 wt% first solvent. The formed coating of the hard felt coating has high adhesion fastness with the carbon fiber hard felt, and is high in hardness, wear-resistant and heat-resistant. The carbon fiber hard felt includes a hard felt body 1, a first coating 2, a first carbon protection layer 3, a second coating 4 and a second carbon protection layer 5 which are arranged in sequence from inside to outside. Among them, both the first coating 2 and the second coating 4 are made of any one of the above hard felt coatings. The first coating in the coating of the carbon fiber hard felt can not only harden the surface of the hard felt, but also make the surface of the final carbon fiber hard felt smoother and flatter after polishing the first coating.

Description

Technical Field

[0001] The present invention relates to the field of coatings, and in particular to a hard felt coating, a preparation method thereof, a carbon fiber hard felt, and a preparation method thereof. Background Art

[0002] Carbon fiber hard felt is often used in high-temperature environments containing corrosive impurities, and it is prone to aging and thinning problems, shortening the service life of the carbon fiber hard felt. However, carbon fiber hard felt is expensive, and the large consumption of carbon fiber hard felt will lead to a significant increase in production costs.

[0003] Currently, in related technologies, in order to delay the aging of carbon fiber hard felt, a method of directly depositing a silicon carbide coating on the outer surface of the carbon fiber hard felt is usually adopted to reduce the influence of high temperature or corrosive impurities on the carbon fiber hard felt, so as to achieve the purpose of extending the service life of the carbon fiber hard felt.

[0004] However, the adhesion of the silicon carbide coating on the surface of the carbon fiber hard felt is weak, and in high-temperature and corrosive environments, the silicon carbide coating is prone to peeling off from the carbon fiber hard felt. At the same time, in the actual application process, the carbon fiber hard felt needs to frequently enter and exit the high-temperature furnace, and under multiple frictions, the silicon carbide coating with weak adhesion fastness is also prone to peeling off from the carbon fiber hard felt. Therefore, it is of great research significance to provide a coating with high adhesion fastness and wear resistance to the carbon fiber hard felt to improve the protection of the carbon fiber hard felt and extend its service life. Summary of the Invention

[0005] In order to effectively extend the service life of carbon fiber hard felt, the present application provides a hard felt coating, a preparation method thereof, a carbon fiber hard felt, and a preparation method thereof.

[0006] The hard felt coating provided by the present application adopts the following technical solutions:

[0007] A hard felt coating is made of raw materials in the following weight percentages:

[0008] Furan resin: 20 - 25%

[0009] Modified phenolic resin: 5 - 8%

[0010] Inorganic silicon hardening resin: 5 - 8%

[0011] Emulsifying thickener: 1 - 2%

[0012] Filler: 18 - 26%

[0013] Film-forming auxiliary agent: 2 - 3%

[0014] First solvent: 30 - 49%;

[0015] The filler is selected from carbon powder or a filler mainly composed of carbon powder.

[0016] By adopting the above technical solution, the furan resin, the modified phenolic resin and the inorganic silicon hardening resin cooperate synergistically, effectively improving the adhesion stability and heat resistance stability between the hard felt coating and the carbon fiber hard felt, enabling the coating formed by the hard felt coating to stably protect the carbon fiber hard felt and effectively extending the service life of the carbon fiber hard felt. In addition, the emulsifying thickener can evenly disperse the furan resin, the modified phenolic resin and the inorganic silicon hardening resin into the solvent. The filler is selected from carbon powder or a filler mainly composed of carbon powder. The main purpose is to increase the coating thickness and also provide adsorption points for the subsequent deposition of propane decomposition products on the coating, which is beneficial to improving the adhesion stability between the propane decomposition products and the coating, thereby further improving the heat resistance of the coating.

[0017] Optionally, the modified phenolic resin is an organosilicon-modified phenolic resin. By raw materials, the organosilicon-modified phenolic resin comprises the following components in parts by weight:

[0018] Phenolic resin: 20 - 30 parts

[0019] Isocyanate group silane: 4 - 9 parts

[0020] Terminal epoxy group polysiloxane: 5 - 10 parts

[0021] Polyester polyol: 2 - 4 parts

[0022] Catalyst: 1 - 3 parts

[0023] Second solvent: 100 parts.

[0024] By adopting the above technical solution, using isocyanate group silane, terminal epoxy group polysiloxane and polyester polyol to modify the phenolic resin together can not only further improve the wear resistance of the coating, but also improve the alkali resistance and solvent resistance of the coating.

[0025] Optionally, the preparation method of the organosilicon-modified phenolic resin comprises the following steps:

[0026] Add the phenolic resin, polyester polyol and catalyst into the second solvent, heat while stirring to 100 - 120 °C, and then keep heating and refluxing for 1 - 2 h to obtain an intermediate product;

[0027] Add the isocyanate group silane and terminal epoxy group polysiloxane into the intermediate product, and continue to heat and reflux at 100 - 120 °C for 2 - 3 h to obtain the organosilicon-modified phenolic resin.

[0028] The organosilicon-modified phenolic resin prepared by the above method can not only further improve the wear resistance of the coating, but also improve the alkali resistance and solvent resistance of the coating.

[0029] Optionally, the filler includes carbon powder, silicon carbide, hollow glass microspheres, and aluminum oxide. Based on the content of the hard felt coating, the proportion of the carbon powder is 15 - 20 wt%, the proportion of the silicon carbide is 1 - 2 wt%, the proportion of the hollow microspheres is 1 - 2 wt%, and the proportion of the aluminum oxide is 1 - 2 wt%.

[0030] By adopting the above technical solution, the filler of this composition can not only improve the adhesion stability between the propane decomposition product and the coating, but also improve the fluidity and heat resistance of the coating, which is beneficial to obtaining a heat-resistant and smooth-surfaced coating.

[0031] Optionally, the emulsifying thickener is selected from at least one of hydroxyethyl cellulose and methyl hydroxyethyl cellulose, and the first solvent is water.

[0032] By adopting the above technical solution, water is a non-toxic and environmentally friendly solvent, which is beneficial to reducing environmental pollution. Furan resin, modified phenolic resin, and inorganic silicon hardening resin are insoluble in water. Adding hydroxyethyl cellulose or methyl hydroxyethyl cellulose can form an emulsion system of the water-insoluble furan resin, modified phenolic resin, and inorganic silicon hardening resin with water, thereby forming a uniform coating system, which plays a key role in improving the stability of the hard felt coating.

[0033] Optionally, the film-forming aid is selected from at least one of diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol n-butyl ether.

[0034] In a second aspect, a preparation method of a hard felt coating provided by this application adopts the following technical solution:

[0035] A preparation method of a hard felt coating includes the following steps:

[0036] While stirring, add the filler to the first solvent, and after stirring evenly, obtain the premix A;

[0037] While stirring, add furan resin, modified phenolic resin, and inorganic silicon hardening resin to the premix A, and after stirring evenly, obtain the premix B;

[0038] While stirring, add the film-forming aid to the mixture B, and after stirring evenly, obtain the hard felt coating.

[0039] By adopting the above technical solution, it is beneficial to improve the uniform dispersion of each raw material, thereby obtaining a uniform hard felt coating.

[0040] In a third aspect, a carbon fiber hard felt provided by this application adopts the following technical solution:

[0041] A carbon fiber hard felt, comprising a hard felt body, a first coating, a first carbon protection layer, a second coating, and a second carbon protection layer which are arranged in sequence from inside to outside; wherein, the first coating and the second coating are made of the hard felt coating described in any one of the above.

[0042] Fourthly, a preparation method of the carbon fiber hard felt provided by the present application adopts the following technical solution:

[0043] A preparation method of a carbon fiber hard felt, comprising the following steps:

[0044] First brushing: evenly brush the hard felt coating described in any one of the above on the surface of the hard felt body, bake and dry it, and then polish it to form a first coating on the surface of the hard felt body;

[0045] First deposition: deposit a first carbon protection layer on the side of the first coating facing away from the hard felt body;

[0046] Second brushing: brush the hard felt coating described in any one of the above on the side of the first carbon protection layer facing away from the first coating, bake and dry it to form a second coating;

[0047] Second deposition: deposit a second carbon protection layer on the side of the second coating facing away from the first carbon protection layer to obtain a carbon fiber hard felt.

[0048] By adopting the above technical solution, the first brushing of the hard felt coating can not only harden the surface of the carbon fiber hard felt, but also make the surface flat by polishing the first coating and then perform the second brushing and deposition, so that the surface of the final carbon fiber hard felt is smoother.

[0049] Optionally, the coating amounts of the first coating and the second coating are controlled at 700 - 900 g / m², and the drying temperatures of the first coating and the second coating are controlled at 140 - 160 °C.

[0050] By adopting the above technical solution, controlling the thickness of the first coating and the second coating within the above range is beneficial to improving the overall stability of the carbon fiber hard felt.

[0051] To sum up, the technical solution of the present application has at least the following beneficial effects:

[0052] (1) The synergistic cooperation of furan resin, modified phenolic resin, and inorganic silicon hardening resin effectively improves the adhesion stability and heat resistance stability between the hard felt coating and the carbon fiber hard felt, so that the coating formed by the hard felt coating can stably protect the carbon fiber hard felt, effectively extending the service life of the carbon fiber hard felt;

[0053] (2) The phenolic resin is modified with isocyanate group silane, terminal epoxy group polysiloxane and polyester polyol, which can not only further improve the wear resistance of the coating, but also improve the alkali resistance and solvent resistance of the coating.

[0054] (3) The filler composed of carbon powder, silicon carbide, hollow microspheres and aluminum oxide in a specific ratio can not only improve the adhesion stability between the propane decomposition product and the coating, but also improve the fluidity and heat resistance of the coating, which is beneficial to obtaining a heat-resistant and smooth-surface coating. Description of the Drawings

[0055] Figure 1 It is a schematic structural diagram of the carbon fiber hard felt of the present application.

[0056] Description of the Reference Numerals:

[0057] 1. Hard felt body; 2. First coating; 3. First carbon protection layer; 4. Second coating; 5. Second carbon protection layer. Detailed Embodiments

[0058] The present application discloses a hard felt coating, which is made of 20 - 25 wt% furan resin, 5 - 8 wt% modified phenolic resin, 5 - 8 wt% inorganic silicon hardening resin, 1 - 2 wt% emulsifying thickener, 18 - 26 wt% filler, 2 - 3 wt% film-forming aid and 30 - 49 wt% first solvent.

[0059] Among them, the modified phenolic resin is selected from at least one of organosilicon-modified phenolic resin and epoxy-modified phenolic resin.

[0060] The emulsifying thickener is selected from at least one of hydroxyethyl cellulose and methyl hydroxyethyl cellulose. The main function of the emulsifying thickener is to emulsify and thicken, so that the water-insoluble furan resin, modified phenolic resin and inorganic silicon hardening resin form an emulsion system with water, thereby forming a uniform coating system, which plays a key role in improving the stability of the hard felt coating. Among them, the emulsifying thickener is preferably hydroxyethyl cellulose or methyl hydroxyethyl cellulose with a molecular weight in the range of 60,000 - 100,000.

[0061] The filler is selected from carbon powder or a filler mainly composed of carbon powder. Using carbon powder as the main filler can not only increase the thickness of the coating, but also provide adsorption points for the subsequent deposition of propane decomposition products on the coating, which is beneficial to improving the adhesion stability between the propane decomposition product and the coating.

[0062] Preferably, based on the content of the hard felt coating, the proportion of toner is 15 - 20 wt%, the proportion of silicon carbide is 1 - 2 wt%, the proportion of hollow microspheres is 1 - 2 wt%, and the proportion of aluminum oxide is 1 - 2 wt%. The fillers in this composition can not only improve the adhesion stability between the propane decomposition product and the coating, but also improve the fluidity and heat resistance of the coating, which is beneficial to obtaining a heat-resistant and smooth coating surface.

[0063] The film-forming auxiliary is selected from at least one of diethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol n-butyl ether.

[0064] The first solvent is preferably non-toxic and pollution-free water, which can reduce environmental pollution.

[0065] In the above-mentioned hard felt coating, furan resin is used as the main film-forming substance, enabling the coating to adhere to the carbon fiber hard felt. Modified phenolic resin is used as an auxiliary film-forming substance, which can not only further improve the adhesion between the hard felt coating and the carbon fiber hard felt, but also assist in improving the heat resistance of the coating. The main function of the inorganic silicon hardening resin is to increase the hardness of the coating formed by the hard felt coating, improve the wear resistance of the coating, make the coating not easily fall off from the hard felt carbon fiber, and at the same time improve the heat resistance of the coating. That is, through the synergistic cooperation of furan resin, modified phenolic resin, and inorganic silicon hardening resin, the adhesion stability and heat resistance stability between the hard felt coating and the carbon fiber hard felt are effectively improved, enabling the coating formed by the hard felt coating to stably protect the carbon fiber hard felt and effectively extending the service life of the carbon fiber hard felt.

[0066] However, since furan resin, modified phenolic resin, and inorganic silicon hardening resin are all insoluble in water, it is difficult for furan resin, modified phenolic resin, and inorganic silicon hardening resin to be evenly dispersed in water. Therefore, the inventor added at least one of hydroxyethyl cellulose and methyl hydroxyethyl cellulose as an emulsifying thickener on the basis of furan resin, modified phenolic resin, and inorganic silicon hardening resin, enabling furan resin, modified phenolic resin, and inorganic silicon hardening resin to form an emulsion system with water, and solving the problem that furan resin, modified phenolic resin, and inorganic silicon hardening resin cannot be evenly dispersed.

[0067] Preferably, the modified phenolic resin is an organosilicon-modified phenolic resin made from the following raw materials by weight. Specifically, based on the raw materials, the organosilicon-modified phenolic resin includes the following components by weight:

[0068] Phenolic resin: 20 - 30 parts

[0069] Isocyanate group silane: 4 - 9 parts

[0070] Terminal epoxy group polysiloxane: 5 - 10 parts

[0071] Polyester polyol: 2 - 4 parts

[0072] Catalyst: 1 - 2 parts

[0073] Second solvent: 100 parts.

[0074] Among them, the isocyanate group - containing silane is selected from at least one of 3 - isocyanatopropyltrimethoxysilane and 3 - isocyanatopropyltriethoxysilane.

[0075] The polyester polyol is selected from at least one of polycarbonate diol and polycaprolactone diol, and the molecular weight of the polyester polyol is preferably 1000 - 2000.

[0076] The catalyst package is a composition of a tertiary amine catalyst and an organotin catalyst. The tertiary amine catalyst is selected from at least one of N - ethylmorpholine and N - methylmorpholine, and the organotin catalyst is preferably dioctyloxide tin.

[0077] The solvent is a composition of ethyl acetate and xylene, and the weight ratio of ethyl acetate to xylene is preferably (55 - 65):(35 - 45).

[0078] The preparation method of the above - mentioned preferably organosilicon - modified phenolic resin includes the following steps:

[0079] Add phenolic resin, polyester polyol and catalyst into the second solvent, heat up to 100 - 120 °C while stirring, and then keep heating under reflux for 1 - 2 h to obtain an intermediate product;

[0080] Add isocyanate group - containing silane and terminal epoxy - group polyorganosiloxane into the intermediate product, and continue to heat under reflux at 100 - 120 °C for 2 - 3 h to obtain the organosilicon - modified phenolic resin.

[0081] Using isocyanate group - containing silane, terminal epoxy - group polyorganosiloxane and polyester polyol to modify phenolic resin together can not only further improve the wear - resistance of the coating, but also improve the alkali - resistance and solvent - resistance of the coating.

[0082] Among them, the preparation method of the hard felt coating includes the following steps:

[0083] Add fillers into the solvent while stirring, control the stirring speed at 400 - 500 r / min, and obtain premix A after stirring evenly;

[0084] Add furan resin, modified phenolic resin and inorganic silicon hardening resin into premix A while stirring, control the stirring speed at 500 - 600 r / min, and obtain premix B after stirring evenly;

[0085] While stirring, a film-forming auxiliary is added to Mixture B, and the stirring speed is controlled at 1000 - 1200 r / min. After stirring evenly, a hard felt coating is obtained.

[0086] In addition, the present application also provides a carbon fiber hard felt. Referring to Figure 1 , it includes a hard felt body 1, a first coating 2, a first carbon protection layer 3, a second coating 4, and a second carbon protection layer 5 arranged in sequence from the inside to the outside. Among them, both the first coating 2 and the second coating 4 are made of any one of the above-mentioned hard felt coatings.

[0087] The preparation method of the carbon fiber hard felt includes the following steps:

[0088] First brushing: The hard felt coating is evenly brushed on the surface of the hard felt body 1, and the coating amount is controlled at 700 - 900 g / square meter. Then it is put into an oven for baking and drying. The baking temperature is 140 - 160 °C, and the baking time is 1.5 - 2.5 h. After cooling, it is polished with sandpaper to form the first coating 2 on the surface of the hard felt body 1;

[0089] First deposition: The polished hard felt body 1 is put into a high-temperature furnace for the first deposition. When the temperature reaches 900 °C, propane is introduced. After introducing propane, the furnace pressure is increased to 600 - 700 Pa, and it is kept warm for 9.5 - 10.5 h, so as to deposit the first carbon protection layer 3 on the side of the first coating 2 facing away from the hard felt body 1; After the temperature in the furnace drops below 100 °C, it is taken out of the furnace;

[0090] Second brushing: The hard felt coating is brushed on the side of the first carbon protection layer 3 facing away from the first coating 2, and the coating amount is controlled at 700 - 900 g / square meter. Then it is put into an oven for baking and drying. The baking temperature is 140 - 160 °C, and the baking time is 1.5 - 2.5 h to form the second coating 4;

[0091] Second deposition: The hard felt body 1 with the formed second coating 4 is put into the high-temperature furnace again for the second deposition. When the temperature reaches 900 °C, propane is introduced. After introducing propane, the furnace pressure is increased to 600 - 700 Pa, and it is kept warm for 9.5 - 10.5 h, so as to deposit the second carbon protection layer 5 on the side of the second coating 4 facing away from the first carbon protection layer 3. After the temperature in the furnace drops below 100 °C, it is taken out of the furnace to obtain the carbon fiber hard felt.

[0092] Among them, the first brushing of the hard felt coating can not only harden the surface of the hard felt, but also make the surface flat by polishing the first coating 2 and then performing the second brushing and deposition, which can make the surface of the final carbon fiber hard felt smoother and flatter.

[0093] The following is an illustration of the present application in combination with specific experiments. Among them, unless otherwise specified, the raw materials used in each experiment are products from the same manufacturer and of the same model.

[0094] Preparation Example

[0095] Preparation Example 1

[0096] An organosilicon-modified phenolic resin, comprising 20 kg of phenolic resin, 9 kg of 3-isocyanatopropyltrimethoxysilane, 2 kg of polycaprolactone diol with a molecular weight of 1500, 0.3 kg of N-ethylmorpholine, 0.7 kg of dioctyltin oxide, 55 kg of ethyl acetate, and 45 kg of xylene.

[0097] The preparation method of the above organosilicon-modified phenolic resin comprises the following steps:

[0098] Add the phenolic resin, polycaprolactone diol, N-ethylmorpholine, and dioctyltin oxide into the mixed solution of ethyl acetate and xylene, heat up to 110 °C while stirring, and then keep heating under reflux at a constant temperature for 1.5 h to obtain an intermediate product;

[0099] Add 3-isocyanatopropyltrimethoxysilane to the intermediate product, and continue to heat under reflux at 110 °C for 2.5 h to obtain the organosilicon-modified phenolic resin.

[0100] Preparation Example 2

[0101] An organosilicon-modified phenolic resin, comprising 20 kg of phenolic resin, 9 kg of epoxy-terminated polysiloxane JF-526, 2 kg of polycaprolactone diol with a molecular weight of 1500, 0.3 kg of N-ethylmorpholine, 0.7 kg of dioctyltin oxide, 55 kg of ethyl acetate, and 45 kg of xylene.

[0102] The preparation method of the above organosilicon-modified phenolic resin comprises the following steps:

[0103] Add the phenolic resin, polycaprolactone diol, N-ethylmorpholine, and dioctyltin oxide into the mixed solution of ethyl acetate and xylene, heat up to 110 °C while stirring, and then keep heating under reflux at a constant temperature for 1.5 h to obtain an intermediate product;

[0104] Add the epoxy-terminated polysiloxane to the intermediate product, and continue to heat under reflux at 110 °C for 2.5 h to obtain the organosilicon-modified phenolic resin.

[0105] Preparation Example 3

[0106] An organosilicon-modified phenolic resin, comprising 20 kg of phenolic resin, 4 kg of 3-isocyanatopropyltrimethoxysilane, 5 kg of epoxy-terminated polysiloxane JF-526, 0.3 kg of N-ethylmorpholine, 0.7 kg of dioctyltin oxide, 55 kg of ethyl acetate, and 45 kg of xylene.

[0107] The preparation method of the above organosilicon-modified phenolic resin comprises the following steps:

[0108] Phenolic resin, N-ethylmorpholine and dioctyltin oxide were added to a mixed solution of ethyl acetate and xylene, and the temperature was raised to 110 °C while stirring, and then heated under reflux at a constant temperature for 1.5 h to obtain an intermediate product;

[0109] 3-Isocyanatopropyltrimethoxysilane and terminal epoxy polysiloxane were added to the intermediate product, and heating under reflux was continued at 110 °C for 2.5 h to obtain an organosilicon-modified phenolic resin.

[0110] Preparation Example 4

[0111] An organosilicon-modified phenolic resin, comprising 20 kg of phenolic resin, 4 kg of 3-isocyanatopropyltrimethoxysilane, 5 kg of terminal epoxy polysiloxane JF-526, 2 kg of polycaprolactone diol with a molecular weight of 1500, 0.3 kg of N-ethylmorpholine, 0.7 kg of dioctyltin oxide, 55 kg of ethyl acetate and 45 kg of xylene.

[0112] The preparation method of the above-mentioned organosilicon-modified phenolic resin comprises the following steps:

[0113] Phenolic resin, polycaprolactone diol, N-ethylmorpholine and dioctyltin oxide were added to a mixed solution of ethyl acetate and xylene, and the temperature was raised to 110 °C while stirring, and then heated under reflux at a constant temperature for 1.5 h to obtain an intermediate product;

[0114] 3-Isocyanatopropyltrimethoxysilane and terminal epoxy polysiloxane were added to the intermediate product, and heating under reflux was continued at 110 °C for 2.5 h to obtain an organosilicon-modified phenolic resin.

[0115] Preparation Example 5

[0116] An organosilicon-modified phenolic resin, comprising 25 kg of phenolic resin, 6 kg of 3-isocyanatopropyltrimethoxysilane, 7.5 kg of terminal epoxy polysiloxane JF-526, 3 kg of polycaprolactone diol with a molecular weight of 1500, 0.4 kg of N-ethylmorpholine, 1.1 kg of dioctyltin oxide, 60 kg of ethyl acetate and 40 kg of xylene.

[0117] The preparation method of the above-mentioned organosilicon-modified phenolic resin comprises the following steps:

[0118] Phenolic resin, polycaprolactone diol, N-ethylmorpholine and dioctyltin oxide were added to a mixed solution of ethyl acetate and xylene, and the temperature was raised to 110 °C while stirring, and then heated under reflux at a constant temperature for 1.5 h to obtain an intermediate product;

[0119] Add 3-isocyanatopropyltrimethoxysilane and epoxy-terminated polysiloxane to the intermediate product, and continue to heat and reflux at 110 °C for 2.5 h to obtain the silicone-modified phenolic resin.

[0120] Preparation Example 6

[0121] A silicone-modified phenolic resin, comprising 30 kg of phenolic resin, 9 kg of 3-isocyanatopropyltrimethoxysilane, 10 kg of epoxy-terminated polysiloxane JF-526, 4 kg of polycaprolactone diol with a molecular weight of 1500, 0.5 kg of N-ethylmorpholine, 1.5 kg of dioctyltin oxide, 65 kg of ethyl acetate, and 35 kg of xylene.

[0122] The preparation method of the above silicone-modified phenolic resin comprises the following steps:

[0123] Add the phenolic resin, polycaprolactone diol, N-ethylmorpholine, and dioctyltin oxide to the mixed solution of ethyl acetate and xylene, heat up to 110 °C while stirring, and then keep heating and refluxing at a constant temperature for 1.5 h to obtain an intermediate product;

[0124] Add 3-isocyanatopropyltrimethoxysilane and epoxy-terminated polysiloxane to the intermediate product, and continue to heat and reflux at 110 °C for 2.5 h to obtain the silicone-modified phenolic resin.

[0125] Example

[0126] Example 1

[0127] A hard felt coating is made of 20 wt% furan resin kpl-25646, 5 wt% silicone-modified phenolic resin prepared in Preparation Example 1, 5 wt% inorganic silicon hardening resin SJ-32F, 1 wt% hydroxyethyl cellulose with a molecular weight of 80000, 18 wt% carbon powder, 2 wt% diethylene glycol butyl ether, and 49 wt% water.

[0128] The preparation method of the coating comprises the following steps:

[0129] Add the carbon powder to the water while stirring, control the stirring speed at 450 r / min, and stir for 2 min to obtain the premix A;

[0130] Add the furan resin, silicone-modified phenolic resin, and inorganic silicon hardening resin to the premix A in sequence while stirring, control the stirring speed at 550 r / min, and stir for 2 min to obtain the premix B;

[0131] Add the diethylene glycol butyl ether to the mixture B while stirring, and then slowly add the hydroxyethyl cellulose, control the stirring speed at 1100 r / min, and stir for 1 h to obtain the hard felt coating.

[0132] Example 2

[0133] A hard felt coating is made of 25 wt% furan resin kpl-25646, 8 wt% silicone-modified phenolic resin prepared in Preparation Example 1, 8 wt% inorganic silicon hardening resin SJ-32F, 2 wt% hydroxyethyl cellulose with a molecular weight of 80,000, 25 wt% carbon powder, 2 wt% diethylene glycol butyl ether, and 30 wt% water.

[0134] The preparation method of this coating includes the following steps:

[0135] While stirring, add carbon powder to water, control the stirring speed at 450 r / min, and stir for 2 min to obtain premix A;

[0136] While stirring, sequentially add furan resin, silicone-modified phenolic resin, and inorganic silicon hardening resin to premix A, control the stirring speed at 550 r / min, and stir for 2 min to obtain premix B;

[0137] While stirring, add diethylene glycol butyl ether to mixture B, and then slowly add hydroxyethyl cellulose, control the stirring speed at 1100 r / min, and stir for 1 h to obtain the hard felt coating.

[0138] Example 3

[0139] A hard felt coating is made of 22 wt% furan resin kpl-25646, 6 wt% silicone-modified phenolic resin prepared in Preparation Example 1, 6 wt% inorganic silicon hardening resin SJ-32F, 1 wt% hydroxyethyl cellulose with a molecular weight of 80,000, 18 wt% carbon powder, 1 wt% silicon carbide, 1 wt% hollow microspheres, 1 wt% aluminum oxide, 3 wt% diethylene glycol butyl ether, and 41 wt% water.

[0140] The preparation method of this coating includes the following steps:

[0141] While stirring, sequentially add carbon powder, silicon carbide, hollow microspheres, and aluminum oxide to water, control the stirring speed at 450 r / min, and stir for 2 min to obtain premix A;

[0142] While stirring, sequentially add furan resin, silicone-modified phenolic resin, and inorganic silicon hardening resin to premix A, control the stirring speed at 550 r / min, and stir for 2 min to obtain premix B;

[0143] While stirring, add diethylene glycol butyl ether to mixture B, and then slowly add hydroxyethyl cellulose, control the stirring speed at 1100 r / min, and stir for 1 h to obtain the hard felt coating.

[0144] Example 4

[0145] A hard felt coating, different from Example 3 in that:

[0146] The silicone-modified phenolic resin is replaced with the silicone-modified phenolic resin prepared in Preparation Example 2 in equal amounts.

[0147] Example 5

[0148] A hard felt coating, different from Example 3 in that:

[0149] The silicone-modified phenolic resin is replaced with the silicone-modified phenolic resin prepared in Preparation Example 3 in equal amounts.

[0150] Example 6

[0151] A hard felt coating, different from Example 3 in that:

[0152] The silicone-modified phenolic resin is replaced with the silicone-modified phenolic resin prepared in Preparation Example 4 in equal amounts.

[0153] Example 7

[0154] A hard felt coating, different from Example 3 in that:

[0155] The silicone-modified phenolic resin is replaced with the silicone-modified phenolic resin prepared in Preparation Example 5 in equal amounts.

[0156] Example 8

[0157] A hard felt coating, different from Example 3 in that:

[0158] The silicone-modified phenolic resin is replaced with the silicone-modified phenolic resin prepared in Preparation Example 6 in equal amounts.

[0159] Example 9

[0160] A hard felt coating, different from Example 7 in that: the ratios of carbon powder, silicon carbide, hollow microspheres and aluminum oxide are different.

[0161] In this example, the proportion of carbon powder is 10 wt%, the proportion of silicon carbide is 4 wt%, the proportion of hollow microspheres is 4 wt%, and the proportion of aluminum oxide is 3 wt%.

[0162] Example 10

[0163] A hard felt coating, different from Example 7 in that: the hollow microspheres are replaced with an equal amount of aluminum oxide.

[0164] Example 11

[0165] A hard felt coating, different from Example 7 in that: the aluminum oxide is replaced with an equal amount of hollow microspheres.

[0166] Comparative Example

[0167] Comparative Example 1

[0168] A hard felt coating, which is different from that of Example 1 in that: the silicone-modified phenolic resin is replaced with an equal amount of furan resin.

[0169] Comparative Example 2

[0170] A hard felt coating, which is different from that of Example 1 in that: the inorganic silicon hardening resin is replaced with an equal amount of furan resin.

[0171] Application Example

[0172] Application Example 1

[0173] A carbon fiber hard felt, comprising a hard felt body, a first coating, a first carbon protection layer, a second coating, and a second carbon protection layer which are arranged in sequence from inside to outside. Among them, both the first coating and the second coating are prepared by brushing the hard felt coating in Example 1.

[0174] The preparation method of the above carbon fiber hard felt includes the following steps:

[0175] First brushing: The hard felt coating in Example 1 is evenly brushed on the surface of the hard felt body, and the coating amount is controlled at 800 g / square meter, and then it is put into an oven for baking and drying. The baking temperature is 150 °C, and the baking time is 2.0 h. After cooling, it is polished with sandpaper to form a first coating on the surface of the hard felt body;

[0176] First deposition: The polished hard felt body is put into a high-temperature furnace for the first deposition. When the temperature reaches 900 °C, propane is introduced. After introducing propane, the furnace pressure is increased to 650 Pa and kept warm for 10 h, so as to deposit a first carbon protection layer on the side of the first coating facing away from the hard felt body; After the temperature in the furnace drops below 100 °C, it is taken out of the furnace;

[0177] Second brushing: The hard felt coating prepared in Example 1 is brushed on the side of the first carbon protection layer facing away from the first coating, and the coating amount is controlled at 800 g / square meter, and then it is put into an oven for baking and drying. The baking temperature is 150 °C, and the baking time is 2.0 h to form a second coating;

[0178] Second deposition: The hard felt body with the second coating formed is put into the high-temperature furnace again for the second deposition. When the temperature reaches 900 °C, propane is introduced. After introducing propane, the furnace pressure is increased to 650 Pa and kept warm for 10 h, so as to deposit a second carbon protection layer on the side of the second coating facing away from the first carbon protection layer. After the temperature in the furnace drops below 100 °C, it is taken out of the furnace to obtain the carbon fiber hard felt.

[0179] Application Example 2

[0180] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 2.

[0181] Application Example 3

[0182] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 3.

[0183] Application Example 4

[0184] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 4.

[0185] Application Example 5

[0186] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 5.

[0187] Application Example 6

[0188] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 6.

[0189] Application Example 7

[0190] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 7.

[0191] Application Example 8

[0192] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 8.

[0193] Application Example 9

[0194] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 9.

[0195] Application Example 10

[0196] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 10.

[0197] Application Example 11

[0198] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Example 11.

[0199] Comparative Application Example

[0200] Comparative Application Example 1

[0201] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Comparative Example 1.

[0202] Comparative Application Example 2

[0203] A carbon fiber hard felt, which is different from Application Example 1 in that both the first coating and the second coating are prepared by brushing the hard felt coating in Comparative Example 2.

[0204] Performance test data Pencil hardness: Refer to GB / T6739-2006 "Determination of film hardness by pencil method for paints and varnishes" for testing. The substrate is carbon fiber hard felt. The hard felt coatings prepared in Examples 1-11 and Comparative Examples 1-2 are evenly coated on the carbon fiber hard felt, dried at 150 °C for 2 h, allowed to stand for 16 h and then tested. Among them, the coating thickness is 0.5 mm.

[0205] Abrasion resistance: Refer to GB / T1768-2006 "Determination of abrasion resistance of paints and varnishes - Rotating rubber wheel method" for testing. The substrate is carbon fiber hard felt. The hard felt coatings prepared in Examples 1-11 and Comparative Examples 1-2 are evenly coated on the carbon fiber hard felt, dried at 150 °C for 2 h, allowed to stand for 20 h and then tested. Among them, the coating thickness is 0.5 mm, and the average number of revolutions to wear through the coating is calculated.

[0206] Surface roughness of carbon fiber hard felt: The surface roughness of the carbon fiber hard felt prepared in Application Examples 1-11 and Comparative Application Examples 1-2 is tested.

[0207] Heat resistance of carbon fiber hard felt: The carbon fiber hard felt prepared in Application Examples 1-11 and Comparative Application Examples 1-2 is pushed into an environment of 2000 °C for treatment for 12 h, and then taken out and cooled for 12 h. Repeat this step 4000 times and 8000 times, and observe whether there is bulging and peeling on the surface of the carbon fiber hard felt.

[0208] Alkali resistance of carbon fiber hard felt: Refer to the immersion method in GB / T 9274-88 to test the carbon fiber hard felt prepared in Application Examples 1-11 and Comparative Application Examples 1-2. The test liquid is 0.005 mol / L sodium hydroxide solution. Observe whether there is bulging and peeling on the surface of the carbon fiber hard felt after soaking for 500 h and 1000 h respectively.

[0209] Ethanol resistance of carbon fiber hard felt: Refer to the immersion method in GB / T 9274-88 to test the carbon fiber hard felt prepared in Application Examples 1-11 and Comparative Application Examples 1-2. The test liquid is ethanol with a volume fraction of 20%. Observe whether there is bulging and peeling on the surface of the carbon fiber hard felt after soaking for 500 h and 1000 h respectively.

[0210] Table 1 Hard Felt Coating Test Data

[0211]

[0212]

[0213] Combining Example 1 and Comparative Examples 1-2 and the data in Table 1, it can be seen that the addition of inorganic silicon hardening resin and organosilicon-modified phenolic resin can improve the hardness and wear resistance of the hard felt coating.

[0214] Combining Examples 3-8 and the data in Table 1, it can be seen that the organosilicon-modified phenolic resin obtained by co-modifying the hard felt coating with isocyanate group silane, terminal epoxy group polysiloxane and polyester polyol can further effectively improve the wear resistance of the hard felt coating.

[0215] Table 2 Carbon Fiber Hard Felt Test Data

[0216]

[0217] Combining Application Example 1 and Comparative Application Examples 1-2 and the data in Table 2, it can be seen that when the organosilicon-modified phenolic resin or the inorganic silicon hardening resin is respectively replaced by an equal amount of furan resin, the high-temperature resistance between the coating and the carbon fiber hard felt both decreases. The reason is that the addition of the organosilicon-modified phenolic resin and the inorganic silicon hardening resin can improve the heat resistance of the coating. In addition, when the organosilicon-modified phenolic resin or the inorganic silicon hardening resin is respectively replaced by an equal amount of furan resin, the alkali resistance and ethanol resistance between the coating and the carbon fiber hard felt both decrease, which may be caused by the reduction of the adhesion fastness between the coating and the carbon fiber hard felt.

[0218] Combining Application Example 1 and Application Example 3 or Application Example 7 and Application Examples 9-11 and the data in Table 2, it can be seen that when the filler is a composition with a specific ratio of carbon powder, silicon carbide, hollow microspheres and aluminum oxide, it can not only improve the surface smoothness of the carbon fiber hard felt, but also ensure the bonding fastness between the carbon protection layer and the coating, which is beneficial to obtaining a carbon fiber hard felt with better heat resistance.

[0219] Combining Application Examples 3-8 and the data in Table 2, it can be seen that the organosilicon-modified phenolic resin obtained by co-modifying the hard felt coating with isocyanate group silane, terminal epoxy group polysiloxane and polyester polyol can also improve the alkali resistance and ethanol resistance of the carbon fiber hard felt, which is beneficial to further extending the service life of the carbon fiber hard felt.

[0220] This specific implementation manner is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications without creative contributions to this specific implementation manner as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A hard felt coating, characterized in that: Made from the following raw materials by weight percentage: Furan resin: 20 - 25% Modified phenolic resin: 5 - 8% Inorganic silicon hardening resin: 5 - 8% Hydroxyethyl cellulose: 1 - 2% Filler: 18 - 26% Film-forming aid: 2 - 3% First solvent: 30 - 49%; The filler is selected from carbon powder or a filler mainly composed of carbon powder; The modified phenolic resin is selected as an organosilicon-modified phenolic resin, and the organosilicon-modified phenolic resin is prepared from the following raw materials: Phenolic resin: 20 - 30 parts Isocyanate group silane: 4 - 9 parts Terminal epoxy group polysiloxane: 5 - 10 parts Polyester polyol: 2 - 4 parts Catalyst: 1 - 3 parts Second solvent: 100 parts; The preparation method of the organosilicon-modified phenolic resin includes the following steps: Add phenolic resin, polyester polyol and catalyst into the second solvent, heat up to 100 - 120 °C while stirring, and then keep heating under constant temperature and reflux for 1 - 2 h to obtain an intermediate product; Add isocyanate group silane and terminal epoxy group polysiloxane into the intermediate product, and continue to heat and reflux at 100 - 120 °C for 2 - 3 h to obtain the organosilicon-modified phenolic resin; The preparation method of the hard felt coating includes the following steps: While stirring, add the filler into the first solvent, and stir evenly to obtain premix A; While stirring, add furan resin, modified phenolic resin and inorganic silicon hardening resin into premix A, and stir evenly to obtain premix B; While stirring, add the film-forming aid into mixture B, and then slowly add hydroxyethyl cellulose, and stir evenly to obtain the hard felt coating.

2. The hard felt coating according to claim 1, wherein: The filler includes carbon powder, silicon carbide, hollow glass microspheres and aluminum oxide. Calculated by the content of the hard felt coating, the proportion of carbon powder is 15 - 20 wt%, the proportion of silicon carbide is 1 - 2 wt%, the proportion of hollow glass microspheres is 1 - 2 wt%, and the proportion of aluminum oxide is 1 - 2 wt%.

3. A hard felt coating according to any one of claims 1-2, characterized in that: The first solvent is water.

4. A hard felt coating according to any one of claims 1-2, characterized in that: The film-forming aid is selected from at least one of diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol n-butyl ether.

5. A method for preparing a hard felt coating according to any one of claims 1-4, characterized in that: Includes the following steps: While stirring, add the filler into the first solvent, and stir evenly to obtain premix A; While stirring, add furan resin, modified phenolic resin and inorganic silicon hardening resin into premix A, and stir evenly to obtain premix B; While stirring, add the film-forming aid into mixture B, and then slowly add hydroxyethyl cellulose, and stir evenly to obtain the hard felt coating.

6. A carbon fiber hard felt, characterized in that: ​ 7. The preparation method of a carbon fiber hard felt according to claim 6, characterized in that: ​ ​ Primary deposition: deposit a first carbon protection layer (3) on the side of the first coating (2) facing away from the hard felt body (1); Secondary brushing: brush the hard felt coating according to any one of claims 1-4 on the side of the first carbon protection layer (3) facing away from the first coating (2), and after baking and drying, form a second coating (4); Secondary deposition: deposit a second carbon protection layer (5) on the side of the second coating (4) facing away from the first carbon protection layer (3) to obtain a carbon fiber hard felt.

8. The preparation method of a carbon fiber hard felt according to claim 7, wherein: The coating amounts of the first coating (2) and the second coating (4) are controlled at 700-900 g / m², and the drying temperatures of the first coating (2) and the second coating (4) are controlled at 140-160 °C.

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