Low friction coefficient composite sheet and method for manufacturing the same

Abstract

The application relates to the technical field of composite boards, in particular to a low-friction-coefficient composite board and a preparation method thereof. Epoxy resin is selected as a composite board base material, lightweight, high-strength, high- and low-temperature-resistant carbon fibers are selected as reinforcing fibers, lubricating fillers are introduced into the composite board, pre-impregnated resin is prepared by compounding different types of epoxy resins, the pre-impregnated resin is coated on release paper after being hot-melted, PE film is coated on the pre-impregnated resin, resin film is obtained, unidirectional carbon fibers are flattened and arranged between two layers of resin film, hot pressing, slitting and winding are carried out, single-layer pre-impregnated material is obtained, and the single-layer pre-impregnated material is laminated and pressed to prepare the composite board. The fillers are modified, sodium alginate is used as an auxiliary, blocky molybdenum disulfide is treated by adopting a liquid phase stripping method, functionalized molybdenum disulfide nanosheets containing a large number of hydroxyl groups and carboxyl groups are prepared, and then a melamine derivative flame retardant containing amino groups is grafted.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically a low-friction coefficient composite material and its preparation method. Background Technology

[0002] For objects that come into contact with each other by sliding or rolling, friction and wear are important causes of energy consumption and material failure. All moving surfaces will generate friction and wear, and the economic losses caused by friction every year are huge. Developing low-friction coefficient wear-resistant materials suitable for multiple fields and working conditions has economic significance and practical value.

[0003] To reduce material loss caused by wear on the two contact surfaces, lightweight and easy-to-process resin wear-resistant plates have been rapidly developed compared with traditional metal materials. Generally, fillers with self-lubricating and wear-resistant properties, such as graphite, carbon fiber, and molybdenum disulfide, are added to the resin to improve the wear resistance of the resin plate. However, it also has problems such as poor strength, poor flame retardancy, and limited corrosion resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a low-friction coefficient composite material and its preparation method to solve the problems in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] S1: Mix and stir bisphenol A type epoxy resin, phenolic epoxy resin, bisphenol F type epoxy resin and modified epoxy resin, heat to melt, vacuum degas, cool and set aside to obtain component A;

[0007] S2: Mix, stir, grind, and disperse epoxy resin, curing agent, accelerator, filler, silane coupling agent, and dispersant to obtain component B;

[0008] S3: Mix and disperse components A and B, then cool to obtain prepreg resin;

[0009] S4: The prepreg resin is melted and coated onto the release paper, and then covered with PE film to obtain a resin film;

[0010] S5: Place unidirectional carbon fiber between two resin films, perform a hot-pressing process, slit and roll up to obtain a single-layer prepreg.

[0011] S6: A low-friction coefficient composite board is obtained by stacking single-layer prepregs and performing a second hot-pressing process.

[0012] Furthermore, in step S1, the working conditions for heating to the melting point are: temperature 150-160℃, time 0.5-1.5h; the working conditions for vacuum degassing treatment are: vacuum degree 0.2-0.4MPa, time 0.5-1.5h; and cooling to 80-95℃ for later use.

[0013] Furthermore, in step S2, the mixing and stirring rate is 300-500 rpm, and the grinding and dispersing are carried out using a three-roll mill, grinding 3-4 times.

[0014] Furthermore, in step S3, the working conditions for mixing, stirring, and dispersing are: vacuum degree of 0.2-0.4MPa, stirring speed of 20-30rpm, dispersion speed of 200-400rpm, and temperature of 70-85℃.

[0015] Furthermore, the mixing ratio of component A to component B is (75-113):(35-65).

[0016] Furthermore, in step S5, the working conditions for the first hot pressing treatment are: temperature of 90-105℃ and pressure of 1-1.5MPa.

[0017] Furthermore, in step S6, the working conditions for the secondary hot pressing treatment are: temperature of 140℃-160℃, pressure of 0.5-2MPa, and time of 90-120min.

[0018] Furthermore, by weight, the raw material composition of component A is: 45-50 parts of bisphenol A type epoxy resin, 15-25 parts of phenolic epoxy resin, 0-8 parts of bisphenol F type epoxy resin, and 15-30 parts of modified epoxy resin.

[0019] Furthermore, by weight, the raw material composition of component B is: 18-30 parts epoxy resin, 5-10 parts curing agent, 1-2 parts accelerator, 10-30 parts filler, 1-1.5 parts silane coupling agent, and 0-1 parts dispersant.

[0020] Furthermore, the bisphenol A type epoxy resin is one or more of NPEL-128, NPES-901, and KF41.

[0021] Furthermore, the phenolic epoxy resin is one or a combination of NPCN-704 and NPPN-638S.

[0022] Furthermore, the modified epoxy resin is one or more of the following: carboxyl-terminated butadiene-acrylonitrile rubber modified epoxy resin, phenoxy-modified epoxy resin, and polyurethane modified epoxy resin.

[0023] Furthermore, the modified epoxy resin is one or more of the following: carboxyl-terminated butadiene-acrylonitrile rubber modified epoxy resin R341, phenoxy modified epoxy resin, and polyurethane modified epoxy resin 102C-5H.

[0024] Furthermore, the epoxy resin is one or a combination of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0025] Furthermore, the epoxy resin is one or more of the following: bisphenol A type epoxy resin NPEL-128, bisphenol A type epoxy resin NPEL-127, and bisphenol F type epoxy resin NPEF-170.

[0026] Furthermore, the curing agent is dicyandiamide, and the accelerator is one or a combination of organic urea accelerators and imidazole accelerators.

[0027] Furthermore, the organic urea accelerator is one or more of UR500, UR300, and UR700 in combination.

[0028] Furthermore, the filler is one or a combination of molybdenum disulfide, kaolin, graphite, titanium dioxide, zirconium dioxide, alumina, and calcium carbonate.

[0029] Furthermore, the dispersant is an alkylammonium salt copolymer.

[0030] Furthermore, the filler is a composite molybdenum disulfide, and its preparation includes the following steps:

[0031] (1) Mix sodium alginate and deionized water, heat to 48-52℃ and keep warm for 1-2 hours, add molybdenum disulfide, sonicate for 5-6 hours, stir for 1 minute every 20 minutes during sonication, centrifuge, wash, freeze dry to obtain functionalized molybdenum disulfide.

[0032] (2) Under a nitrogen atmosphere, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, functionalized molybdenum disulfide and DMSO are mixed, and an amino-containing melamine-derived flame retardant is added. The mixture is kept at 35-37℃ for 6-8 hours, cooled, filtered, washed and dried to obtain composite molybdenum disulfide.

[0033] Furthermore, the preparation of amino-containing melamine-derived flame retardants includes the following steps:

[0034] 1) Under a nitrogen atmosphere, melamine, allyl bromide and DMSO are mixed, sodium carbonate is added, and the mixture is stirred at 18-25℃ for 2 hours. The temperature is then raised to 118-122℃ and held for 5-6 hours. The mixture is then rotary evaporated, cooled, filtered, washed and dried to obtain double-bonded melamine.

[0035] 2) Mix 3-mercaptopropylmethyldimethoxysilane, decamethylcyclopentasiloxane and hexamethyldisiloxane, add trifluoromethanesulfonic acid and deionized water, keep warm at 75-80℃ until transparent, cool down to 18-25℃, wash and distill to obtain mercaptosilicone oil;

[0036] 3) Under a nitrogen atmosphere, double-bonded melamine, mercapto silicone oil, and DMSO are mixed, a photoinitiator is added, the temperature is raised to 50-60℃, and irradiated with 365nm ultraviolet light for 10-12h to obtain an amino-containing melamine-derived flame retardant.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] This invention provides a low-friction coefficient composite board and its preparation method. Through raw material and process design, a high-strength, corrosion-resistant, highly flame-retardant, and low-friction coefficient composite board is prepared.

[0039] In this invention, epoxy resin is selected as the base material for the composite board. Compared with other thermosetting resins, it has better mechanical properties, insulation properties, adhesion properties, and processing flexibility. Lightweight, high-strength carbon fiber with good resistance to high and low temperatures is selected as the reinforcing fiber. One of graphite and molybdenum disulfide, a lubricating filler, is introduced into the composite board to reduce the coefficient of friction. Prepreg resin is prepared by controlling the compounding of different types of epoxy resins. The prepreg resin is then melted and coated onto release paper, and then covered with a PE film to obtain a resin film. Unidirectional carbon fiber is flattened and placed between two layers of resin film. Hot pressing is used to melt the resin and impregnate the carbon fiber. The resin is then cut and wound to obtain a single layer of prepreg. The single layer of prepreg is stacked and pressed together to prepare the composite board. Compared with the commonly available carbon fiber reinforced epoxy resin composite boards, the coefficient of friction is significantly reduced.

[0040] To further improve the wear resistance and strength of the composite board, nano-sized fillers were selected for improvement. To ensure uniform dispersion of the nano-sized fillers in the composite board without the addition of additional dispersants, the fillers were modified. Using sodium alginate as an aid, a liquid-phase exfoliation method was employed to treat blocky molybdenum disulfide, preparing functionalized molybdenum disulfide nanosheets with a large number of hydroxyl and carboxyl groups on their surface. These nanosheets were then grafted with an amino-containing melamine-derived flame retardant under the action of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. This improved the uniformity of filler dispersion in the epoxy resin and enhanced the bonding strength between the filler and the base resin, preventing filler detachment under external impact and other conditions. This endowed the composite board with halogen-free high flame retardancy and corrosion resistance.

[0041] The amino-containing melamine-derived flame retardant is prepared by first preparing double-bonded melamine with melamine and allyl bromide, and then reacting it with mercaptosilicone oil via a click reaction. The mercaptosilicone oil is prepared by hydrolytic copolymerization of 3-mercaptopropylmethyldimethoxysilane, decamethylcyclopentasiloxane and hexamethyldisiloxane. The introduction of mercaptosilicone oil endows the composite board with excellent stability, high and low temperature resistance and water resistance, thereby extending the service life of the composite board. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be noted that if the embodiments of the present invention involve directional indicators such as up, down, left, right, front, and back, these directional indicators are only used to explain the relative positional relationship and movement of components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0044] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0045] Example 1: A method for preparing a low-friction coefficient composite board, comprising the following steps:

[0046] S1: Mix and stir bisphenol A type epoxy resin, phenolic epoxy resin and modified epoxy resin, heat to melt, vacuum degas, cool and set aside to obtain component A;

[0047] In step S1, the working conditions for heating to the melting point are: temperature 150℃, time 1.5h; the working conditions for vacuum degassing treatment are: vacuum degree 0.3MPa, time 1h; and cooling to 90℃ for later use.

[0048] By weight, the raw material composition of component A is: 45 parts bisphenol A type epoxy resin, 22 parts phenolic epoxy resin, and 19 parts modified epoxy resin.

[0049] Bisphenol A type epoxy resin is a blend of NPEL-128 and NPES-901 in a mass ratio of 6:39; phenolic epoxy resin is a blend of NPCN-704 and NPPN-638S in a mass ratio of 10:12; modified epoxy resin is a blend of carboxyl-terminated nitrile rubber modified epoxy resin R341, phenoxy modified epoxy resin, and polyurethane modified epoxy resin 102C-5H in a mass ratio of 9:5:5.

[0050] S2: Mix, stir, grind, and disperse epoxy resin, curing agent, accelerator, filler, silane coupling agent, and dispersant to obtain component B;

[0051] By weight, the raw material composition of component B is: 26 parts epoxy resin, 6.8 parts curing agent, 1 part accelerator, 10 parts filler, 1.3 parts silane coupling agent, and 0.5 parts dispersant;

[0052] The epoxy resin is a blend of bisphenol A type epoxy resin NPEL-128 and bisphenol A type epoxy resin NPEL-127 in a mass ratio of 10:16; the curing agent is dicyandiamide; the accelerator is a blend of organic urea accelerator and imidazole accelerator PN-23 in a mass ratio of 0.7:0.3; the organic urea accelerator is a blend of UR500, UR300, and UR700 in a mass ratio of 0.2:0.2:0.3; the filler is flake graphite; and the dispersant is an alkyl ammonium salt copolymer.

[0053] In step S2, the mixing speed is 400 rpm, and the grinding and dispersing are carried out using a three-roll mill, grinding 3 times;

[0054] S3: Mix and disperse components A and B, then cool to obtain prepreg resin;

[0055] In step S3, the working conditions for mixing, stirring and dispersing are: vacuum degree of 0.3MPa, stirring speed of 25rpm, dispersion speed of 300rpm, temperature of 85℃, and mixing ratio of component A to component B of 86:45.6.

[0056] S4: The prepreg resin is melted and coated onto the release paper, and then covered with PE film to obtain a resin film;

[0057] S5: The unidirectional carbon fiber is laid flat between two layers of resin film, hot-pressed once, cut and wound to obtain a single layer of prepreg.

[0058] The working conditions for a single hot pressing process are: temperature 100℃ and pressure 1.2MPa.

[0059] S6: A low-friction coefficient composite board is obtained by stacking single-layer prepregs and performing a second hot-pressing treatment; the working conditions for the second hot-pressing treatment are: temperature of 160℃, pressure of 2MPa, and time of 90min.

[0060] Example 2: A method for preparing a low-friction coefficient composite board, comprising the following steps:

[0061] S1: Mix and stir bisphenol A type epoxy resin, phenolic epoxy resin and modified epoxy resin, heat to melt, vacuum degas, cool and set aside to obtain component A;

[0062] In step S1, the working conditions for heating to the melting point are: temperature 150℃, time 1.5h; the working conditions for vacuum degassing are: vacuum degree 0.2MPa, time 1.5h; and cooling to 80℃ for later use.

[0063] By weight, the raw material composition of component A is: 45 parts bisphenol A type epoxy resin, 15 parts phenolic epoxy resin, and 15 parts modified epoxy resin.

[0064] Bisphenol A type epoxy resin is NPEL-128 and NPES-901 blended in a mass ratio of 6:39; phenolic epoxy resin is NPCN-704 and NPPN-638S blended in a mass ratio of 7:8; modified epoxy resin is carboxyl-terminated nitrile rubber modified epoxy resin R341, phenoxy modified epoxy resin, and polyurethane modified epoxy resin 102C-5H blended in a mass ratio of 7:4:4.

[0065] S2: Mix, stir, grind and disperse epoxy resin, curing agent, accelerator, filler and silane coupling agent to obtain component B;

[0066] By weight, the raw material composition of component B is: 18 parts epoxy resin, 5 parts curing agent, 1 part accelerator, 10 parts filler, and 1 part silane coupling agent.

[0067] The epoxy resin is a blend of bisphenol A type epoxy resin NPEL-128 and bisphenol A type epoxy resin NPEL-127 in a mass ratio of 12:6; the curing agent is dicyandiamide; the accelerator is a blend of organic urea accelerator and imidazole accelerator PN-23 in a mass ratio of 0.7:0.3; the organic urea accelerator is a blend of UR500, UR300 and UR700 in a mass ratio of 0.2:0.2:0.3.

[0068] In step S2, the mixing speed is 300 rpm, and the grinding and dispersing are carried out using a three-roll mill, grinding 3 times;

[0069] S3: Mix and disperse components A and B, then cool to obtain prepreg resin;

[0070] In step S3, the working conditions for mixing, stirring and dispersing are: vacuum degree of 0.2MPa, stirring speed of 20rpm, dispersion speed of 200rpm, temperature of 70℃, and mixing ratio of component A to component B of 75:35.

[0071] S4: The prepreg resin is melted and coated onto the release paper, and then covered with PE film to obtain a resin film;

[0072] S5: The unidirectional carbon fiber is laid flat between two layers of resin film, hot-pressed once, cut and wound to obtain a single layer of prepreg.

[0073] The working conditions for a single hot pressing process are: temperature 90℃ and pressure 1.5MPa.

[0074] S6: A low-friction coefficient composite board is obtained by stacking single-layer prepregs and performing a second hot-pressing treatment; the working conditions for the second hot-pressing treatment are: temperature 140℃, pressure 2MPa, and time 120min.

[0075] The filler is a composite molybdenum disulfide, and its preparation includes the following steps:

[0076] (1) Mix 5g sodium alginate and 100mL deionized water, heat to 48℃ and keep warm for 2h, add 1g molybdenum disulfide, sonicate for 5h, stir for 1min every 20min during sonication, centrifuge, wash, freeze dry to obtain functionalized molybdenum disulfide.

[0077] (2) Under a nitrogen atmosphere, 0.3g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 0.4g of N-hydroxysuccinimide, 1.2g of functionalized molybdenum disulfide and 20mL of DMSO were mixed, and 0.8g of amino-containing melamine-derived flame retardant was added. The mixture was kept at 35℃ for 8h, cooled, filtered, washed and dried to obtain composite molybdenum disulfide;

[0078] The preparation of the amino-containing melamine-derived flame retardant includes the following steps:

[0079] 1) Under a nitrogen atmosphere, 15g of melamine, 14.4g of allyl bromide and 90mL of DMSO were mixed, and 0.2g of sodium carbonate was added. The mixture was stirred at 18℃ for 2h, heated to 118℃ and kept at that temperature for 6h, and then rotary evaporated, cooled, filtered, washed and dried to obtain double-bonded melamine.

[0080] 2) Mix 0.4 mol 3-mercaptopropylmethyldimethoxysilane, 0.8 mol decamethylcyclopentasiloxane, and 0.01 mol hexamethyldisiloxane, add 7.4 g trifluoromethanesulfonic acid and 11.5 mL deionized water, keep warm at 75 °C until transparent, cool down to 25 °C, wash and distill to obtain mercaptosilicone oil;

[0081] 3) Under a nitrogen atmosphere, 1.4g of double-bonded melamine, 0.5g of mercapto silicone oil and 15mL of DMSO were mixed, 0.02g of photoinitiator was added, the temperature was raised to 50℃, and the mixture was irradiated with 365nm ultraviolet light for 10h to obtain an amino-containing melamine-derived flame retardant.

[0082] Example 3: A method for preparing a low-friction coefficient composite board, comprising the following steps:

[0083] S1: Mix and stir bisphenol A type epoxy resin, phenolic epoxy resin and modified epoxy resin, heat to melt, vacuum degas, cool and set aside to obtain component A;

[0084] In step S1, the working conditions for heating to the melting point are: temperature 155℃, time 1h; the working conditions for vacuum degassing treatment are: vacuum degree 0.3MPa, time 1h; and cooling to 90℃ for later use.

[0085] By weight, the raw material composition of component A is: 47 parts bisphenol A type epoxy resin, 22 parts phenolic epoxy resin, and 19 parts modified epoxy resin.

[0086] Bisphenol A type epoxy resin is NPEL-128 and NPES-901 blended in a mass ratio of 8:39; phenolic epoxy resin is NPCN-704 and NPPN-638S blended in a mass ratio of 10:12; modified epoxy resin is carboxyl-terminated nitrile rubber modified epoxy resin R341, phenoxy modified epoxy resin, and polyurethane modified epoxy resin 102C-5H blended in a mass ratio of 9:5:5.

[0087] S2: Mix, stir, grind and disperse epoxy resin, curing agent, accelerator, filler and silane coupling agent to obtain component B;

[0088] By weight, the raw material composition of component B is: 30 parts epoxy resin, 8 parts curing agent, 1.6 parts accelerator, 20 parts filler, and 1.2 parts silane coupling agent;

[0089] The epoxy resin is a blend of bisphenol A type epoxy resin NPEL-128 and bisphenol A type epoxy resin NPEL-127 in a mass ratio of 18:12; the curing agent is dicyandiamide; the accelerator is a blend of organic urea accelerator and imidazole accelerator PN-23 in a mass ratio of 1.1:0.5; the organic urea accelerator is a blend of UR500, UR300 and UR700 in a mass ratio of 0.3:0.3:0.5.

[0090] In step S2, the mixing speed is 400 rpm, and the grinding and dispersing are carried out using a three-roll mill, grinding 4 times;

[0091] S3: Mix and disperse components A and B, then cool to obtain prepreg resin;

[0092] In step S3, the working conditions for mixing, stirring and dispersing are: vacuum degree of 0.3MPa, stirring speed of 25rpm, dispersion speed of 300rpm, temperature of 80℃, and mixing ratio of component A to component B of 88:66.1.

[0093] S4: The prepreg resin is melted and coated onto the release paper, and then covered with PE film to obtain a resin film;

[0094] S5: The unidirectional carbon fiber is laid flat between two layers of resin film, hot-pressed once, cut and wound to obtain a single layer of prepreg.

[0095] The working conditions for a single hot pressing process are: temperature 100℃ and pressure 1.2MPa.

[0096] S6: A low-friction coefficient composite board is obtained by stacking single-layer prepregs and performing a second hot-pressing treatment; the working conditions for the second hot-pressing treatment are: temperature 150℃, pressure 1MPa, and time 110min;

[0097] The filler is a composite molybdenum disulfide, and its preparation includes the following steps:

[0098] (1) Mix 5g sodium alginate and 100mL deionized water, heat to 50℃ and keep warm for 1.5h, add 1g molybdenum disulfide, sonicate for 5.5h, stir for 1min every 20min during sonication, centrifuge, wash, freeze dry to obtain functionalized molybdenum disulfide.

[0099] (2) Under a nitrogen atmosphere, 0.3g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 0.4g of N-hydroxysuccinimide, 1.2g of functionalized molybdenum disulfide and 20mL of DMSO were mixed, and 0.8g of amino-containing melamine-derived flame retardant was added. The mixture was kept at 36℃ for 7h, cooled, filtered, washed and dried to obtain composite molybdenum disulfide;

[0100] The preparation of the amino-containing melamine-derived flame retardant includes the following steps:

[0101] 1) Under a nitrogen atmosphere, 15g of melamine, 14.4g of allyl bromide and 90mL of DMSO were mixed, and 0.2g of sodium carbonate was added. The mixture was stirred at 20℃ for 2h, heated to 120℃ and kept at that temperature for 5.5h, then rotary evaporated, cooled, filtered, washed and dried to obtain double-bonded melamine.

[0102] 2) Mix 0.4 mol 3-mercaptopropylmethyldimethoxysilane, 0.8 mol decamethylcyclopentasiloxane, and 0.01 mol hexamethyldisiloxane, add 7.4 g trifluoromethanesulfonic acid and 11.5 mL deionized water, keep warm at 78 °C until transparent, cool down to 20 °C, wash and distill to obtain mercaptosilicone oil;

[0103] 3) Under a nitrogen atmosphere, 1.4 g of double-bonded melamine, 0.5 g of mercapto silicone oil and 15 mL of DMSO were mixed, 0.02 g of photoinitiator was added, the temperature was raised to 55 °C, and the mixture was irradiated with 365 nm ultraviolet light for 11 h to obtain an amino-containing melamine-derived flame retardant.

[0104] Example 4: A method for preparing a low-friction coefficient composite board, comprising the following steps:

[0105] S1: Mix and stir bisphenol A type epoxy resin, phenolic epoxy resin and modified epoxy resin, heat to melt, vacuum degas, cool and set aside to obtain component A;

[0106] In step S1, the working conditions for heating to the melting point are: temperature 160℃, time 0.5h; the working conditions for vacuum degassing treatment are: vacuum degree 0.4MPa, time 0.5h; and cooling to 95℃ for later use.

[0107] By weight, the raw material composition of component A is: 50 parts bisphenol A type epoxy resin, 25 parts phenolic epoxy resin, and 30 parts modified epoxy resin.

[0108] Bisphenol A type epoxy resin is a blend of NPEL-128 and NPES-901 in a mass ratio of 7:43; phenolic epoxy resin is a blend of NPCN-704 and NPPN-638S in a mass ratio of 12:13; modified epoxy resin is a blend of carboxyl-terminated nitrile rubber modified epoxy resin R341, phenoxy modified epoxy resin, and polyurethane modified epoxy resin 102C-5H in a mass ratio of 15:7.5:7.5.

[0109] S2: Mix, stir, grind and disperse epoxy resin, curing agent, accelerator, filler and silane coupling agent to obtain component B;

[0110] By weight, the raw material composition of component B is: 30 parts epoxy resin, 10 parts curing agent, 2 parts accelerator, 30 parts filler, and 1.5 parts silane coupling agent.

[0111] The epoxy resin is a blend of bisphenol A type epoxy resin NPEL-128 and bisphenol A type epoxy resin NPEL-127 in a mass ratio of 18:12; the curing agent is dicyandiamide; the accelerator is a blend of organic urea accelerator and imidazole accelerator PN-23 in a mass ratio of 1.4:0.6; the organic urea accelerator is a blend of UR500, UR300 and UR700 in a mass ratio of 0.4:0.4:0.6.

[0112] In step S2, the mixing speed is 500 rpm, and the grinding and dispersing are carried out using a three-roll mill, grinding 4 times;

[0113] S3: Mix and disperse components A and B, then cool to obtain prepreg resin;

[0114] In step S3, the working conditions for mixing, stirring and dispersing are: vacuum degree of 0.4MPa, stirring speed of 30rpm, dispersion speed of 200rpm, temperature of 85℃, and mixing ratio of component A to component B of 105:73.5.

[0115] S4: The prepreg resin is melted and coated onto the release paper, and then covered with PE film to obtain a resin film;

[0116] S5: The unidirectional carbon fiber is laid flat between two layers of resin film, hot-pressed once, cut and wound to obtain a single layer of prepreg.

[0117] The working conditions for a single hot pressing process are: temperature 105℃ and pressure 1MPa.

[0118] S6: A low-friction coefficient composite board is obtained by stacking single-layer prepregs and performing a second hot-pressing treatment; the working conditions for the second hot-pressing treatment are: temperature 160℃, pressure 2MPa, and time 90min.

[0119] The filler is a composite molybdenum disulfide, and its preparation includes the following steps:

[0120] (1) Mix 5g sodium alginate and 100mL deionized water, heat to 52℃ and keep warm for 1h, add 1g molybdenum disulfide, sonicate for 6h, stir for 1min every 20min during sonication, centrifuge, wash, freeze dry to obtain functionalized molybdenum disulfide.

[0121] (2) Under a nitrogen atmosphere, 0.3g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 0.4g of N-hydroxysuccinimide, 1.2g of functionalized molybdenum disulfide and 20mL of DMSO were mixed, and 0.8g of amino-containing melamine-derived flame retardant was added. The mixture was kept at 37℃ for 6h, cooled, filtered, washed and dried to obtain composite molybdenum disulfide;

[0122] The preparation of the amino-containing melamine-derived flame retardant includes the following steps:

[0123] 1) Under a nitrogen atmosphere, 15g of melamine, 14.4g of allyl bromide and 90mL of DMSO were mixed, and 0.2g of sodium carbonate was added. The mixture was stirred at 25℃ for 2h, heated to 118℃ and kept at that temperature for 6h, and then rotary evaporated, cooled, filtered, washed and dried to obtain double-bonded melamine.

[0124] 2) Mix 0.4 mol 3-mercaptopropylmethyldimethoxysilane, 0.8 mol decamethylcyclopentasiloxane, and 0.01 mol hexamethyldisiloxane, add 7.4 g trifluoromethanesulfonic acid and 11.5 mL deionized water, keep warm at 80 °C until transparent, cool down to 18 °C, wash and distill to obtain mercaptosilicone oil;

[0125] 3) Under a nitrogen atmosphere, 1.4g of double-bonded melamine, 0.5g of mercapto silicone oil and 15mL of DMSO were mixed, 0.02g of photoinitiator was added, the temperature was raised to 60℃, and the mixture was irradiated with 365nm ultraviolet light for 12h to obtain an amino-containing melamine-derived flame retardant.

[0126] Comparative Example 1: Using Example 1 as the control group, the components were as follows (by weight): Component A: 31 parts NPEL-128 epoxy resin, 65 parts NPES-901 epoxy resin, 10 parts NPCN-704 phenolic epoxy resin, 3 parts R341 carboxyl-terminated nitrile rubber modified epoxy resin, and 3 parts phenoxy-modified epoxy resin; Component B (by weight): 20 parts NPEL-128 epoxy resin, 7.1 parts dicyandiamide curing agent, 0.55 parts UR500 accelerator, 0.25 parts PN-23 accelerator, 0.25 parts fumed silica, and 0.5 parts KH-560 coupling agent; The mixing ratio of Component A to Component B was 112:28.65, and other processes were normal.

[0127] Comparative Example 2: Using Example 4 as the control group, functionalized molybdenum disulfide was used to replace composite molybdenum disulfide, while other processes were normal.

[0128] In the examples and comparative examples, the number of layers was 40, and the thickness of the prepreg resin after hot melting and cooling was 0.5µm.

[0129] In the examples and comparative examples, the phenoxy-modified epoxy resin was obtained by compounding phenoxy resin and bisphenol A type epoxy resin NPEL-128 at a mass ratio of 1:2.

[0130] Sources of raw materials used (for illustrative purposes only):

[0131] Carboxyl-terminated nitrile butadiene rubber modified epoxy resin R341: Shenzhen Chuchuang Applied Materials Co., Ltd.; Phenoxy resin YX4000: Mitsubishi Chemical; Polyurethane modified epoxy resin 102C-5H: Taizhou Hengchuang Insulation Materials Co., Ltd.; Imidazole accelerator PN-23: Ajinomoto Fine Chemicals Co., Ltd., Japan; Flake graphite: Qingdao Jintao Graphite Co., Ltd.; Alkyl ammonium salt copolymer BYK-9076: BYK Chemicals; Bisphenol A type epoxy resin (NPEL-128, NPEL-127, NPES-901), phenolic epoxy resin (NPCN-704, NPPN-638S): Nan Ya Epoxy Resin (Kunshan) Co., Ltd.; Organic urea accelerator (UR500, UR300, UR700): Azken, Germany; Carbon fiber STS40-24K: Toho, Japan; PE film (0.02mm): Wuxi Jiayou Packaging. Materials Co., Ltd.; Photoinitiator (2-hydroxy-2-methylpropanone, 99%): Shanghai Tongyuan Chemical Co., Ltd.; Allyl bromide (99%): Zouping Mingxing Chemical Co., Ltd.; Dicyandiamide S26828: Shanghai Yuanye Biotechnology Co., Ltd.; Silane coupling agent γ-(2,3-epoxypropoxy)propyltrimethoxysilane G134407, Sodium alginate S100128, Molybdenum disulfide M104967, 1-ethyl -(3-Dimethylaminopropyl)carbodiimide hydrochloride E106172, N-hydroxysuccinimide H109330, melamine M108433, 3-mercaptopropylmethyldimethoxysilane M158195, decamethylcyclopentasiloxane D135850, hexamethyldisiloxane H105443, trifluoromethanesulfonic acid T398955: Aladdin reagent; sodium carbonate, dimethyl sulfoxide, analytical grade, commercially available.

[0132] Performance testing:

[0133] The composite panels prepared in the examples and comparative examples were tested:

[0134] Friction coefficient: The friction coefficient was measured using a friction coefficient measuring instrument; Flame retardancy: The UL-94 vertical burning rating test was conducted; Corrosion resistance: The sample was placed in a 10% sodium chloride aqueous solution and kept at 100℃ for 12 hours. The sample was considered qualified if there were no cavitation, peeling, or breakage, otherwise it was considered unqualified; The results are shown in Table 1.

[0135] Table 1

[0136]

[0137] This invention provides a low-friction coefficient composite board and its preparation method. Through raw material and process design, a high-strength, corrosion-resistant, highly flame-retardant, and low-friction coefficient composite board is prepared.

[0138] Comparing Example 1 with Comparative Example 1, it can be seen that the epoxy resin selected as the composite board base material in this invention has better mechanical properties, insulation properties, adhesion properties, and processing flexibility compared with other thermosetting resins. Lightweight, high-strength carbon fiber with good high and low temperature resistance is selected as the reinforcing fiber. One of graphite and molybdenum disulfide lubricating fillers is introduced into the composite board to reduce the coefficient of friction. Prepreg resin is prepared by controlling the compounding of different types of epoxy resins. The prepreg resin is then hot-melted and coated onto release paper, and then covered with PE film to obtain a resin film. Unidirectional carbon fiber is flattened and placed between two layers of resin film, hot-pressed, slit and wound to obtain a single layer of prepreg. The single layer of prepreg is stacked and pressed together to prepare the composite board. Compared with the commonly available carbon fiber reinforced epoxy resin composite boards, the coefficient of friction is significantly reduced.

[0139] Comparing Example 4 with Comparative Example 2, it can be seen that in order to further improve the wear resistance and strength of the composite board, nano-level fillers were selected for improvement. At the same time, in order to ensure that the nano-level fillers are uniformly dispersed in the composite board without the addition of additional dispersants, the fillers were modified. Using sodium alginate as an aid, blocky molybdenum disulfide was treated by liquid phase exfoliation to prepare functionalized molybdenum disulfide nanosheets with a large number of hydroxyl and carboxyl groups on the surface. Then, under the action of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, an amino-containing melamine-derived flame retardant was grafted onto it. This improved the uniformity of the filler dispersion in the epoxy resin, while also improving the bonding strength between the filler and the base resin, preventing problems such as filler detachment under external impact, and endowing the composite board with halogen-free high flame retardancy and corrosion resistance.

[0140] The amino-containing melamine-derived flame retardant is prepared by first preparing double-bonded melamine with melamine and allyl bromide, and then reacting it with mercaptosilicone oil via a click reaction. The mercaptosilicone oil is prepared by hydrolytic copolymerization of 3-mercaptopropylmethyldimethoxysilane, decamethylcyclopentasiloxane and hexamethyldisiloxane. The introduction of mercaptosilicone oil endows the composite board with excellent stability, high and low temperature resistance and water resistance, thereby extending the service life of the composite board.

[0141] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the present invention's specification under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing a low-friction coefficient composite board, characterized in that, Includes the following steps: S1: Mix and stir bisphenol A type epoxy resin, phenolic epoxy resin, bisphenol F type epoxy resin and modified epoxy resin, heat to melt, vacuum degas, cool and set aside to obtain component A; S2: Mix, stir, grind, and disperse epoxy resin, curing agent, accelerator, filler, silane coupling agent, and dispersant to obtain component B; S3: Mix and disperse components A and B, then cool to obtain prepreg resin; S4: The prepreg resin is melted and coated onto the release paper, and then covered with PE film to obtain a resin film; S5: Place unidirectional carbon fiber between two resin films, perform a hot-pressing process, slit and roll up to obtain a single-layer prepreg. S6: A low-friction coefficient composite board is obtained by stacking single-layer prepregs and performing a secondary hot-pressing process. The filler is a composite molybdenum disulfide, and its preparation includes the following steps: (1) Mix sodium alginate and deionized water, heat to 48-52℃ and keep warm for 1-2 hours, add molybdenum disulfide, sonicate for 5-6 hours, stir for 1 minute every 20 minutes during sonication, centrifuge, wash, freeze dry to obtain functionalized molybdenum disulfide. (2) Under a nitrogen atmosphere, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, functionalized molybdenum disulfide and dimethyl sulfoxide are mixed, and an amino-containing melamine-derived flame retardant is added. The mixture is kept at 35-37℃ for 6-8 hours, cooled, filtered, washed and dried to obtain composite molybdenum disulfide. The preparation of the amino-containing melamine-derived flame retardant includes the following steps: 1) Under a nitrogen atmosphere, melamine, allyl bromide and dimethyl sulfoxide are mixed, sodium carbonate is added, and the mixture is stirred at 18-25℃ for 2 hours. The temperature is then raised to 118-122℃ and held for 5-6 hours. The mixture is then rotary evaporated, cooled, filtered, washed and dried to obtain double-bonded melamine. 2) Mix 3-mercaptopropylmethyldimethoxysilane, decamethylcyclopentasiloxane and hexamethyldisiloxane, add trifluoromethanesulfonic acid and deionized water, keep warm at 75-80℃ until transparent, cool down to 18-25℃, wash and distill to obtain mercaptosilicone oil; 3) Under a nitrogen atmosphere, double-bonded melamine, mercaptosilicone oil, and dimethyl sulfoxide are mixed, a photoinitiator is added, the temperature is raised to 50-60℃, and irradiated with 365nm ultraviolet light for 10-12h to obtain an amino-containing melamine-derived flame retardant.

2. The method for preparing a low-friction coefficient composite board according to claim 1, characterized in that, In step S1, the working conditions for heating to the melting point are: temperature 150-160℃, time 0.5-1.5h; the working conditions for vacuum degassing are: vacuum degree 0.2-0.4MPa, time 0.5-1.5h; and cooling to 80-95℃ for later use.

3. The method for preparing a low-friction coefficient composite material according to claim 1, characterized in that, In step S2, the mixing and stirring rate is 300-500 rpm, and the grinding and dispersion are carried out using a three-roll mill, grinding 3-4 times; in step S3, the working conditions for mixing, stirring and dispersing are: vacuum degree of 0.2-0.4 MPa, stirring rate of 20-30 rpm, dispersion rate of 200-400 rpm, and temperature of 70-85℃; by weight, the mixing ratio of component A to component B is (75-113):(35-65).

4. The method for preparing a low-friction coefficient composite material according to claim 1, characterized in that, In step S5, the working conditions for the first hot pressing treatment are: temperature 90-105℃, pressure 1-1.5MPa; in step S6, the working conditions for the second hot pressing treatment are: temperature 140℃-160℃, pressure 0.5-2MPa, time 90-120min.

5. The method for preparing a low-friction coefficient composite material according to claim 1, characterized in that, By weight, the raw material composition of component A is: 45-50 parts of bisphenol A type epoxy resin, 15-25 parts of phenolic epoxy resin, 0-8 parts of bisphenol F type epoxy resin, and 15-30 parts of modified epoxy resin. By weight, the raw material composition of component B is: 18-30 parts epoxy resin, 5-10 parts curing agent, 1-2 parts accelerator, 10-30 parts filler, 1-1.5 parts silane coupling agent, and 0-1 parts dispersant.

6. The method for preparing a low-friction coefficient composite material according to claim 1, characterized in that, The modified epoxy resin is one or more of the following: carboxyl-terminated butadiene-acrylonitrile rubber modified epoxy resin, phenoxy-modified epoxy resin, and polyurethane modified epoxy resin.

7. The method for preparing a low-friction coefficient composite board according to claim 1, characterized in that, The epoxy resin is one or a combination of bisphenol A type epoxy resin and bisphenol F type epoxy resin; the curing agent is dicyandiamide; the accelerator is one or a combination of organic urea accelerator and imidazole accelerator; and the dispersant is an alkyl ammonium salt copolymer.

8. A low-friction coefficient composite board, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

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