A toughened epoxy resin plastic mold and its preparation method

Abstract

The present invention relates to the technical field of resin molds, and specifically to a toughened epoxy resin plastic mold and a preparation method thereof. In order to improve the toughness of the epoxy resin mold, a modified nano-carbon fiber component is added to the epoxy resin matrix. Adding it to the epoxy resin matrix can effectively disperse stress, thereby improving the toughness of the material. On this basis, the present invention also conducts a modification treatment on the nano-carbon fiber material, introducing a borane structure and fluorine element on its surface, and conducting an epoxidation treatment on its surface, so that the nano-carbon fiber can participate in the curing of the epoxy resin, improving the bonding strength with the epoxy resin matrix. Moreover, the fluorine element and borane group introduced in this process can further enhance the stability and friction resistance of the epoxy resin, reducing the damage suffered by the mold during use.

Description

Technical Field

[0001] The invention relates to the technical field of resin moulds, in particular to a toughened epoxy resin plastic mould and a preparation method thereof. Background Art

[0002] Resin-based mold material is a new functional material that has emerged in recent years. It has excellent shape stability, rigidity, impact toughness and hardness. Compared with traditional metal molds, resin-based molds also have good processing performance and corrosion resistance, and are light in weight and low in cost, which has played an important role in promoting the rapid development of the mold industry.

[0003] At present, the mainstream resin-based mold materials in the industry are mostly epoxy resin-based materials, which have high chemical resistance and excellent dimensional stability after cross-linking. However, epoxy resin is highly brittle and has poor high temperature resistance, which seriously affects the use of epoxy resin mold materials. Summary of the invention

[0004] The purpose of the present invention is to provide a toughened epoxy resin plastic mold and a preparation method thereof to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing a toughened epoxy resin plastic mold, comprising the following steps:

[0006] S1. Preparation of modified carbon nanofibers;

[0007] S11. The nanocarbon fibers are dispersed in deionized water, dispersed by ultrasonic oscillation for 3-5 hours, centrifuged and precipitated, dried to constant weight, dispersed in concentrated sulfuric acid, cooled to constant temperature in an ice-water bath, phosphoric acid is added thereto, stirred and mixed for 1 hour, potassium permanganate is added, the reaction is continued for 1 hour, and an equal volume of deionized water with concentrated sulfuric acid is added, the temperature is raised to 80-90°C, the reaction is continued by stirring for 0.5-1 hour, centrifuged and precipitated, the precipitate is dispersed in hydrogen peroxide, ultrasonically oscillated for 0.5-1 hour, centrifuged and precipitated, the precipitate is washed 2-5 times with hydrochloric acid and anhydrous ethanol respectively, the precipitate is dispersed in deionized water again, sodium hydroxide and chloroacetic acid are added thereto, the reaction is stirred for 12-24 hours, the precipitate is centrifuged and separated, washed with deionized water, and dried to obtain carboxylated nanocarbon fibers;

[0008] S12. Disperse decaborane in toluene, protect under nitrogen atmosphere, heat to 78-81°C, stir and mix for 0.5-1h, add acetonitrile with the same volume of toluene, continue to mix and react for 2-4h, add bis(4-aminophenyl)acetylene, continue to stir and react for 12-24h, add pyridine and carboxylated nano-carbon fibers, keep warm and react for 4-8h, centrifuge and precipitate, wash the precipitate with xylene 2-5 times, and obtain borane-modified nano-carbon fibers;

[0009] S13. Dispersing the borane-modified nanocarbon fibers in 1,4-di(2',3'-epoxypropyl)perfluorobutane, ultrasonically dispersing for 1-2 hours, heating to 85-90°C, stirring for 2-4 hours, centrifuging and separating the precipitate, washing the precipitate with 2,2,2-trifluoroethanol for 2-3 times, and vacuum evaporating to constant weight to obtain modified nanocarbon fibers;

[0010] S2. Mix the epoxy resin and modified nano-carbon fiber by weight, stir and mix for 30-50 minutes, add the curing agent and defoaming agent, continue mixing for 3-5 minutes, vacuum defoam the resulting mixture, pour it into a mold, heat it to 78-85°C, cure it for 2-5 hours, demold it, use 200-800 mesh sandpaper to polish the surface to make it smooth, and obtain a toughened epoxy resin plastic mold.

[0011] Furthermore, in terms of weight, in step S11, the mass ratio of the nano-carbon fibers, concentrated sulfuric acid, phosphoric acid and potassium permanganate is 5: (150-300): (10-20): (15-30).

[0012] Furthermore, in step S11, the mass ratio of the nano-carbon fibers, sodium hydroxide and chloroacetic acid is 5: (10-15): (15-20) in parts by weight.

[0013] Furthermore, in step S12, the mass ratio of decaborane, bis(4-aminophenyl)acetylene, pyridine and carboxylated nano-carbon fibers is (10-20): (17.8-23): (0.04-0.08): 5 in parts by weight.

[0014] Furthermore, in terms of parts by weight, in step S13, the mass ratio of the borane-modified carbon nanofiber to 1,4-di(2',3'-epoxypropyl)perfluorobutane is 5:(100-500).

[0015] Furthermore, in step S2, the toughened epoxy resin plastic mold is composed of 75-85 parts of epoxy resin, 5-15 parts of modified nano-carbon fibers, 12-18 parts of curing agent and 0.1-0.5 parts of defoaming agent, in parts by weight.

[0016] Furthermore, in step S2, the epoxy resin is any one of bisphenol A epoxy resin E-44 and bisphenol A epoxy resin E-51;

[0017] The curing agent is dicyandiamide; the defoaming agent is an acrylic defoaming agent.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] In order to improve the flexibility of epoxy resin molds, the present invention adds a modified carbon nanofiber component to the epoxy resin matrix. The carbon nanofiber is a nanoscale material with an extremely high aspect ratio. Adding it to the epoxy resin matrix can effectively disperse stress, thereby enhancing the impact resistance of the material and further improving the toughness of the material.

[0020] On this basis, the present invention also performs a modification treatment on the nano-carbon fiber material. The present invention first performs an oxidation treatment on the surface of the nano-carbon fiber, and further performs a carboxylation treatment on the surface. After that, under the action of Lewis base, bis(4-aminophenyl)acetylene containing acetylene and amino groups is used to react with decaborane, so that borane replaces acetylene addition, thereby introducing an amino group into the borane structure, and further reacting it with the carboxylated nano-carbon fiber, introducing a borane structure on the surface of the nano-carbon fiber, the introduction of the borane structure can effectively improve the flame retardant properties of the material, and the borane structure has rigidity, which can effectively enhance the mechanical properties of the material;

[0021] In addition, the present invention further uses 1,4-di(2',3'-epoxypropyl)perfluorobutane containing fluorine element to treat the borane-modified nano-carbon fibers, thereby introducing fluorine element and epoxy structure on the surface, so that the nano-carbon fibers can participate in the curing of the epoxy resin, improve the bonding strength with the epoxy resin matrix, and enhance the mechanical properties; and the introduction of fluorine element can effectively improve the chemical stability of the material, improve the corrosion resistance of the material, and thereby reduce the corrosion damage of the mold during use. DETAILED DESCRIPTION

[0022] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0023] The nano-carbon fibers used in the examples and comparative examples of the present application have a diameter of 150-200 nm, a length of 70-20 μm, and an average aspect ratio of 70; the epoxy resin used is Phoenix brand E51 (WSR618) 0164C epoxy resin; the defoamer used is ZY-1354 defoamer;

[0024] Example 1. A method for preparing a toughened epoxy resin plastic mold, comprising the following steps:

[0025] S1. Preparation of modified carbon nanofibers;

[0026] S11. By weight, 5 parts of nano-carbon fibers were dispersed in deionized water, ultrasonically dispersed for 4 hours, centrifuged and precipitated, dried to constant weight, and then dispersed in 150 parts of concentrated sulfuric acid. After cooling to a constant temperature in an ice-water bath, 10 parts of phosphoric acid were added thereto. After stirring and mixing for 1 hour, 15 parts of potassium permanganate were added. After continuing to react for 1 hour, an equal volume of deionized water with concentrated sulfuric acid was added. The temperature was raised to 85°C, and the stirring reaction was continued for 1 hour. After centrifugation and precipitation, the precipitate was dispersed in hydrogen peroxide. After ultrasonic vibration reaction for 1 hour, the precipitate was centrifuged and separated, and the precipitate was washed 4 times with hydrochloric acid and anhydrous ethanol respectively. The precipitate was dispersed in deionized water again, 10 parts of sodium hydroxide and 15 parts of chloroacetic acid were added thereto, and the reaction was stirred for 12 hours. After separation, the precipitate was centrifuged and washed with deionized water, and dried to obtain carboxylated nano-carbon fibers;

[0027] S12. Disperse 10 parts of decaborane in toluene by weight, protect under nitrogen atmosphere, heat to 78°C, stir and mix for 1 hour, add acetonitrile with the same volume of toluene, continue to mix and react for 4 hours, add 17.8 parts of bis(4-aminophenyl)acetylene, continue to stir and react for 24 hours, add 0.08 parts of pyridine and 5 parts of carboxylated nanocarbon fibers, keep warm and react for 8 hours, centrifuge and separate the precipitate, wash the precipitate with xylene 5 times, and obtain borane-modified nanocarbon fibers;

[0028] S13. Disperse 5 parts of borane-modified nanocarbon fibers into 100 parts of 1,4-di(2',3'-epoxypropyl)perfluorobutane by weight, disperse by ultrasonication for 2 hours, heat to 85-90°C, stir for 4 hours, centrifuge to separate the precipitate, wash the precipitate three times with 2,2,2-trifluoroethanol, and evaporate in vacuo to constant weight to obtain modified nanocarbon fibers;

[0029] S2. Mix 85 parts of epoxy resin and 5 parts of modified nano-carbon fibers by weight, stir and mix for 40 minutes, then add 15 parts of curing agent and 0.4 parts of defoaming agent, continue mixing for 5 minutes, vacuum defoam the mixture, pour it into a mold, heat it to 83°C, cure it for 5 hours, demold it, polish the surface with 200-800 mesh sandpaper to obtain a toughened epoxy resin plastic mold.

[0030] Example 2. A method for preparing a toughened epoxy resin plastic mold, comprising the following steps:

[0031] Compared with Example 1, this embodiment increases the amount of sodium hydroxide and chloroacetic acid added in step S11;

[0032] S1. Preparation of modified carbon nanofibers;

[0033] S11. By weight, 5 parts of nano-carbon fibers were dispersed in deionized water, ultrasonically dispersed for 4 hours, centrifuged and precipitated, dried to constant weight, and then dispersed in 150 parts of concentrated sulfuric acid. After cooling to a constant temperature in an ice-water bath, 10 parts of phosphoric acid were added thereto. After stirring and mixing for 1 hour, 15 parts of potassium permanganate were added. After continuing to react for 1 hour, an equal volume of deionized water with concentrated sulfuric acid was added. The temperature was raised to 85°C, and the stirring reaction was continued for 1 hour. After centrifugation and precipitation, the precipitate was dispersed in hydrogen peroxide. After ultrasonic vibration reaction for 1 hour, the precipitate was centrifuged and separated, and the precipitate was washed 4 times with hydrochloric acid and anhydrous ethanol respectively. The precipitate was dispersed in deionized water again, 15 parts of sodium hydroxide and 20 parts of chloroacetic acid were added thereto, and the reaction was stirred for 12 hours. After separation, the precipitate was centrifuged and washed with deionized water and dried to obtain carboxylated nano-carbon fibers.

[0034] S12. Disperse 10 parts of decaborane in toluene by weight, protect under nitrogen atmosphere, heat to 78°C, stir and mix for 1 hour, add acetonitrile with the same volume of toluene, continue to mix and react for 4 hours, add 17.8 parts of bis(4-aminophenyl)acetylene, continue to stir and react for 24 hours, add 0.08 parts of pyridine and 5 parts of carboxylated nanocarbon fibers, keep warm and react for 8 hours, centrifuge and separate the precipitate, wash the precipitate with xylene 5 times, and obtain borane-modified nanocarbon fibers;

[0035] S13. Disperse 5 parts of borane-modified nanocarbon fibers into 100 parts of 1,4-di(2',3'-epoxypropyl)perfluorobutane by weight, disperse by ultrasonication for 2 hours, heat to 85-90°C, stir for 4 hours, centrifuge to separate the precipitate, wash the precipitate three times with 2,2,2-trifluoroethanol, and evaporate in vacuo to constant weight to obtain modified nanocarbon fibers;

[0036] S2. Mix 85 parts of epoxy resin and 5 parts of modified nano-carbon fibers by weight, stir and mix for 40 minutes, then add 15 parts of curing agent and 0.4 parts of defoaming agent, continue mixing for 5 minutes, vacuum defoam the mixture, pour it into a mold, heat it to 83°C, cure it for 5 hours, demold it, polish the surface with 200-800 mesh sandpaper to obtain a toughened epoxy resin plastic mold.

[0037] Example 3. A method for preparing a toughened epoxy resin plastic mold, comprising the following steps:

[0038] Compared with Example 1, this example increases the amount of decaborane added in step S12;

[0039] S1. Preparation of modified carbon nanofibers;

[0040] S11. By weight, 5 parts of nano-carbon fibers were dispersed in deionized water, ultrasonically dispersed for 4 hours, centrifuged and precipitated, dried to constant weight, and then dispersed in 150 parts of concentrated sulfuric acid. After cooling to a constant temperature in an ice-water bath, 10 parts of phosphoric acid were added thereto. After stirring and mixing for 1 hour, 15 parts of potassium permanganate were added. After continuing to react for 1 hour, an equal volume of deionized water with concentrated sulfuric acid was added. The temperature was raised to 85°C, and the stirring reaction was continued for 1 hour. After centrifugation and precipitation, the precipitate was dispersed in hydrogen peroxide. After ultrasonic vibration reaction for 1 hour, the precipitate was centrifuged and separated, and the precipitate was washed 4 times with hydrochloric acid and anhydrous ethanol respectively. The precipitate was dispersed in deionized water again, 10 parts of sodium hydroxide and 15 parts of chloroacetic acid were added thereto, and the reaction was stirred for 12 hours. After separation, the precipitate was centrifuged and washed with deionized water, and dried to obtain carboxylated nano-carbon fibers;

[0041] S12. Disperse 15 parts of decaborane in toluene by weight, protect under nitrogen atmosphere, heat to 78°C, stir and mix for 1 hour, add acetonitrile with the same volume of toluene, continue to mix and react for 4 hours, add 17.8 parts of bis(4-aminophenyl)acetylene, continue to stir and react for 24 hours, add 0.08 parts of pyridine and 5 parts of carboxylated nanocarbon fibers, keep warm and react for 8 hours, centrifuge and separate the precipitate, wash the precipitate with xylene 5 times, and obtain borane-modified nanocarbon fibers;

[0042] S13. Disperse 5 parts of borane-modified nanocarbon fibers into 100 parts of 1,4-di(2',3'-epoxypropyl)perfluorobutane by weight, disperse by ultrasonication for 2 hours, heat to 85-90°C, stir for 4 hours, centrifuge to separate the precipitate, wash the precipitate three times with 2,2,2-trifluoroethanol, and evaporate in vacuo to constant weight to obtain modified nanocarbon fibers;

[0043] S2. Mix 85 parts of epoxy resin and 5 parts of modified nano-carbon fibers by weight, stir and mix for 40 minutes, then add 15 parts of curing agent and 0.4 parts of defoaming agent, continue mixing for 5 minutes, vacuum defoam the mixture, pour it into a mold, heat it to 83°C, cure it for 5 hours, demold it, polish the surface with 200-800 mesh sandpaper to obtain a toughened epoxy resin plastic mold.

[0044] Example 4. A method for preparing a toughened epoxy resin plastic mold, comprising the following steps:

[0045] Compared with Example 1, this embodiment increases the amount of modified carbon nanofiber added in step S12;

[0046] S1. Preparation of modified carbon nanofibers;

[0047] S11. By weight, 5 parts of nano-carbon fibers were dispersed in deionized water, ultrasonically dispersed for 4 hours, centrifuged and precipitated, dried to constant weight, and then dispersed in 150 parts of concentrated sulfuric acid. After cooling to a constant temperature in an ice-water bath, 10 parts of phosphoric acid were added thereto. After stirring and mixing for 1 hour, 15 parts of potassium permanganate were added. After continuing to react for 1 hour, an equal volume of deionized water with concentrated sulfuric acid was added. The temperature was raised to 85°C, and the stirring reaction was continued for 1 hour. After centrifugation and precipitation, the precipitate was dispersed in hydrogen peroxide. After ultrasonic vibration reaction for 1 hour, the precipitate was centrifuged and separated, and the precipitate was washed 4 times with hydrochloric acid and anhydrous ethanol respectively. The precipitate was dispersed in deionized water again, 10 parts of sodium hydroxide and 15 parts of chloroacetic acid were added thereto, and the reaction was stirred for 12 hours. After separation, the precipitate was centrifuged and washed with deionized water, and dried to obtain carboxylated nano-carbon fibers;

[0048] S12. Disperse 10 parts of decaborane in toluene by weight, protect under nitrogen atmosphere, heat to 78°C, stir and mix for 1 hour, add acetonitrile with the same volume of toluene, continue to mix and react for 4 hours, add 17.8 parts of bis(4-aminophenyl)acetylene, continue to stir and react for 24 hours, add 0.08 parts of pyridine and 5 parts of carboxylated nanocarbon fibers, keep warm and react for 8 hours, centrifuge and separate the precipitate, wash the precipitate with xylene 5 times, and obtain borane-modified nanocarbon fibers;

[0049] S13. Disperse 5 parts of borane-modified nanocarbon fibers into 100 parts of 1,4-di(2',3'-epoxypropyl)perfluorobutane by weight, disperse by ultrasonication for 2 hours, heat to 85-90°C, stir for 4 hours, centrifuge to separate the precipitate, wash the precipitate three times with 2,2,2-trifluoroethanol, and evaporate in vacuo to constant weight to obtain modified nanocarbon fibers;

[0050] S2. Mix 85 parts of epoxy resin and 15 parts of modified nano-carbon fibers by weight, stir and mix for 40 minutes, then add 15 parts of curing agent and 0.4 parts of defoaming agent, continue mixing for 5 minutes, vacuum defoam the mixture, pour it into a mold, heat it to 83°C, cure it for 5 hours, demold it, polish the surface with 200-800 mesh sandpaper to obtain a toughened epoxy resin plastic mold.

[0051] Comparative Example 1. A method for preparing a toughened epoxy resin plastic mold, comprising the following steps:

[0052] Compared with Example 1, this comparative example only prepared carboxylated carbon nanofibers;

[0053] S1. Preparation of carboxylated carbon nanofibers;

[0054] S11. By weight, 5 parts of nano-carbon fibers were dispersed in deionized water, ultrasonically dispersed for 4 hours, centrifuged and precipitated, dried to constant weight, and then dispersed in 150 parts of concentrated sulfuric acid. After cooling to a constant temperature in an ice-water bath, 10 parts of phosphoric acid were added thereto. After stirring and mixing for 1 hour, 15 parts of potassium permanganate were added. After continuing to react for 1 hour, an equal volume of deionized water with concentrated sulfuric acid was added. The temperature was raised to 85°C, and the stirring reaction was continued for 1 hour. After centrifugation and precipitation, the precipitate was dispersed in hydrogen peroxide. After ultrasonic vibration reaction for 1 hour, the precipitate was centrifuged and separated, and the precipitate was washed 4 times with hydrochloric acid and anhydrous ethanol respectively. The precipitate was dispersed in deionized water again, 10 parts of sodium hydroxide and 15 parts of chloroacetic acid were added thereto, and the reaction was stirred for 12 hours. After separation, the precipitate was centrifuged and washed with deionized water, and dried to obtain carboxylated nano-carbon fibers;

[0055] S2. Mix 85 parts of epoxy resin and 5 parts of carboxylated nano-carbon fibers by weight, stir and mix for 40 minutes, then add 15 parts of curing agent and 0.4 parts of defoaming agent, continue mixing for 5 minutes, vacuum defoam the mixture, pour it into a mold, heat it to 83°C, cure it for 5 hours, demold it, polish the surface with 200-800 mesh sandpaper to obtain a toughened epoxy resin plastic mold.

[0056] Comparative Example 2. A method for preparing a toughened epoxy resin plastic mold, comprising the following steps:

[0057] Compared with Example 1, this comparative example did not perform the modification treatment in step S13;

[0058] S1. Preparation of borane-modified carbon nanofibers;

[0059] S11. By weight, 5 parts of nano-carbon fibers were dispersed in deionized water, ultrasonically dispersed for 4 hours, centrifuged and precipitated, dried to constant weight, and then dispersed in 150 parts of concentrated sulfuric acid. After cooling to a constant temperature in an ice-water bath, 10 parts of phosphoric acid were added thereto. After stirring and mixing for 1 hour, 15 parts of potassium permanganate were added. After continuing to react for 1 hour, an equal volume of deionized water with concentrated sulfuric acid was added. The temperature was raised to 85°C, and the stirring reaction was continued for 1 hour. After centrifugation and precipitation, the precipitate was dispersed in hydrogen peroxide. After ultrasonic vibration reaction for 1 hour, the precipitate was centrifuged and separated, and the precipitate was washed 4 times with hydrochloric acid and anhydrous ethanol respectively. The precipitate was dispersed in deionized water again, 10 parts of sodium hydroxide and 15 parts of chloroacetic acid were added thereto, and the reaction was stirred for 12 hours. After separation, the precipitate was centrifuged and washed with deionized water, and dried to obtain carboxylated nano-carbon fibers;

[0060] S12. Disperse 10 parts of decaborane in toluene by weight, protect under nitrogen atmosphere, heat to 78°C, stir and mix for 1 hour, add acetonitrile with the same volume of toluene, continue to mix and react for 4 hours, add 17.8 parts of bis(4-aminophenyl)acetylene, continue to stir and react for 24 hours, add 0.08 parts of pyridine and 5 parts of carboxylated nanocarbon fibers, keep warm and react for 8 hours, centrifuge and separate the precipitate, wash the precipitate with xylene 5 times, and obtain borane-modified nanocarbon fibers;

[0061] S2. According to the weight percentage, 85 parts of epoxy resin and 5 parts of borane-modified nano-carbon fibers were mixed, and after stirring for 40 minutes, 15 parts of curing agent and 0.4 parts of defoaming agent were added, and the mixture was vacuum-defoamed and poured into a mold. The mixture was heated to 83°C and cured for 5 hours, and then demolded. The surface was smoothed with 200-800 mesh sandpaper to obtain a toughened epoxy resin plastic mold.

[0062] Comparative Example 3. A method for preparing a toughened epoxy resin plastic mold, comprising the following steps:

[0063] Compared with Example 1, this comparative example further increases the amount of modified carbon nanofiber added in step S2;

[0064] S1. Preparation of modified carbon nanofibers;

[0065] S11. By weight, 5 parts of nano-carbon fibers were dispersed in deionized water, ultrasonically dispersed for 4 hours, centrifuged and precipitated, dried to constant weight, and then dispersed in 150 parts of concentrated sulfuric acid. After cooling to a constant temperature in an ice-water bath, 10 parts of phosphoric acid were added thereto. After stirring and mixing for 1 hour, 15 parts of potassium permanganate were added. After continuing to react for 1 hour, an equal volume of deionized water with concentrated sulfuric acid was added. The temperature was raised to 85°C, and the stirring reaction was continued for 1 hour. After centrifugation and precipitation, the precipitate was dispersed in hydrogen peroxide. After ultrasonic vibration reaction for 1 hour, the precipitate was centrifuged and separated, and the precipitate was washed 4 times with hydrochloric acid and anhydrous ethanol respectively. The precipitate was dispersed in deionized water again, 10 parts of sodium hydroxide and 15 parts of chloroacetic acid were added thereto, and the reaction was stirred for 12 hours. After separation, the precipitate was centrifuged and washed with deionized water, and dried to obtain carboxylated nano-carbon fibers;

[0066] S12. Disperse 10 parts of decaborane in toluene by weight, protect under nitrogen atmosphere, heat to 78°C, stir and mix for 1 hour, add acetonitrile with the same volume of toluene, continue to mix and react for 4 hours, add 17.8 parts of bis(4-aminophenyl)acetylene, continue to stir and react for 24 hours, add 0.08 parts of pyridine and 5 parts of carboxylated nanocarbon fibers, keep warm and react for 8 hours, centrifuge and separate the precipitate, wash the precipitate with xylene 5 times, and obtain borane-modified nanocarbon fibers;

[0067] S13. Disperse 5 parts of borane-modified nanocarbon fibers into 100 parts of 1,4-di(2',3'-epoxypropyl)perfluorobutane by weight, disperse by ultrasonication for 2 hours, heat to 85-90°C, stir for 4 hours, centrifuge to separate the precipitate, wash the precipitate three times with 2,2,2-trifluoroethanol, and evaporate in vacuo to constant weight to obtain modified nanocarbon fibers;

[0068] S2. Mix 85 parts of epoxy resin and 30 parts of modified nano-carbon fibers by weight, stir and mix for 40 minutes, then add 15 parts of curing agent and 0.4 parts of defoaming agent, continue mixing for 5 minutes, vacuum defoam the resulting mixture, pour it into a mold, heat it to 83°C, cure it for 5 hours, demold it, polish the surface with 200-800 mesh sandpaper to obtain a toughened epoxy resin plastic mold.

[0069] The toughened epoxy resin plastic molds prepared in Examples 1-4 and Comparative Examples 1-3 were prepared as test samples;

[0070] According to GB / T 1040.2-2022, the tensile strength test was performed on the test samples prepared in Examples 1-4 and Comparative Examples 1-3;

[0071] According to GB / T 1043.2-2018, the test samples prepared in Examples 1-4 and Comparative Examples 1-3 were tested for impact strength;

[0072] The test samples prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to bending strength tests according to GB / T 9341-2008;

[0073] An equal volume of acetone was added to the mixture obtained in step S2 of Example 1-4 and Comparative Example 1-3, and after mixing evenly, the mixture was prepared into a paint film sample, and a salt spray resistance test was performed on the sample according to GB / T 1771-2007;

[0074] According to GB / T 2406, the test samples prepared in Examples 1-4 and Comparative Examples 1-3 were tested for limiting oxygen index;

[0075] The test results are shown in the table below;

[0076]

[0077] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a toughened epoxy resin plastic mold, characterized in that: The following steps are involved: S1. Preparation of modified carbon nanofibers; S11. The nanocarbon fibers are dispersed in deionized water, dispersed by ultrasonic oscillation for 3-5 hours, centrifuged and precipitated, dried to constant weight, dispersed in concentrated sulfuric acid, cooled to constant temperature in an ice-water bath, phosphoric acid is added thereto, stirred and mixed for 1 hour, potassium permanganate is added, the reaction is continued for 1 hour, and an equal volume of deionized water with concentrated sulfuric acid is added, the temperature is raised to 80-90°C, the reaction is continued by stirring for 0.5-1 hour, centrifuged and precipitated, the precipitate is dispersed in hydrogen peroxide, ultrasonically oscillated for 0.5-1 hour, centrifuged and precipitated, the precipitate is washed 2-5 times with hydrochloric acid and anhydrous ethanol respectively, the precipitate is dispersed in deionized water again, sodium hydroxide and chloroacetic acid are added thereto, the reaction is stirred for 12-24 hours, the precipitate is centrifuged and separated, washed with deionized water, and dried to obtain carboxylated nanocarbon fibers; S12. Disperse decaborane in toluene, protect under nitrogen atmosphere, heat to 78-81°C, stir and mix for 0.5-1h, add acetonitrile with the same volume of toluene, continue to mix and react for 2-4h, add bis(4-aminophenyl)acetylene, continue to stir and react for 12-24h, add pyridine and carboxylated nano-carbon fibers, keep warm and react for 4-8h, centrifuge and precipitate, wash the precipitate with xylene 2-5 times, and obtain borane-modified nano-carbon fibers; S13. Dispersing the borane-modified nanocarbon fibers in 1,4-di(2',3'-epoxypropyl)perfluorobutane, ultrasonically dispersing for 1-2 hours, heating to 85-90°C, stirring for 2-4 hours, centrifuging and separating the precipitate, washing the precipitate with 2,2,2-trifluoroethanol for 2-3 times, and vacuum evaporating to constant weight to obtain modified nanocarbon fibers; S2. Mix the epoxy resin and modified nano-carbon fiber by weight, stir and mix for 30-50 minutes, add the curing agent and defoaming agent, continue mixing for 3-5 minutes, vacuum defoam the resulting mixture, pour it into a mold, heat it to 78-85°C, cure it for 2-5 hours, demold it, use 200-800 mesh sandpaper to polish the surface to make it smooth, and obtain a toughened epoxy resin plastic mold.

2. The method for preparing a toughened epoxy resin plastic mold according to claim 1, characterized in that: In terms of weight, in step S11, the mass ratio of the nano-carbon fibers, concentrated sulfuric acid, phosphoric acid and potassium permanganate is 5: (150-300): (10-20): (15-30).

3. The method for preparing a toughened epoxy resin plastic mold according to claim 1, characterized in that: In terms of weight, in step S11, the mass ratio of the nano-carbon fibers, sodium hydroxide and chloroacetic acid is 5: (10-15): (15-20).

4. The method for preparing a toughened epoxy resin plastic mold according to claim 1, characterized in that: In terms of weight, in step S12, the mass ratio of decaborane, bis(4-aminophenyl)acetylene, pyridine and carboxylated nano-carbon fibers is (10-20): (17.8-23): (0.04-0.08):

5.

5. The method for preparing a toughened epoxy resin plastic mold according to claim 1, characterized in that: In terms of parts by weight, in step S13, the mass ratio of the borane-modified carbon nanofiber to 1,4-di(2',3'-epoxypropyl)perfluorobutane is 5:(100-500).

6. The method for preparing a toughened epoxy resin plastic mold according to claim 1, characterized in that: In terms of weight, in step S2, the toughened epoxy resin plastic mold is composed of 75-85 parts of epoxy resin, 5-15 parts of modified nano-carbon fibers, 12-18 parts of curing agent and 0.1-0.5 parts of defoaming agent.

7. The method for preparing a toughened epoxy resin plastic mold according to claim 1, characterized in that: In step S2, the epoxy resin is any one of bisphenol A epoxy resin E-44 and bisphenol A epoxy resin E-51; The curing agent is dicyandiamide; the defoaming agent is an acrylic defoaming agent.

8. A toughened epoxy resin plastic mold prepared by the preparation method according to any one of claims 1 to 7.

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