Low dielectric loss epoxy resin composite material and preparation method thereof

Abstract

The present invention belongs to the technical field of resin composite materials and relates to a low dielectric loss epoxy resin composite material and a preparation method thereof, comprising the following raw materials in parts by mass: 50-60 parts of phenol-type epoxy resin, 5-10 parts of bisphenol A cyanate resin, 5-15 parts of bisphenol F epoxy resin, 5-15 parts of thermoplastic resin, 10-20 parts of wollastonite, 1-10 parts of curing agent, 1-5 parts of accelerator and 1-5 parts of silicon dioxide. The present invention provides a low dielectric loss epoxy resin composite material and a preparation method thereof, with high thermal stability, low dielectric loss and high mechanical strength.

Description

Technical Field

[0001] The invention belongs to the technical field of resin composite materials and relates to a low dielectric loss epoxy resin composite material and a preparation method thereof. Background Art

[0002] Epoxy resin has good mechanical properties, heat resistance, insulation and chemical resistance. However, during the curing process of epoxy resin, a large amount of secondary hydroxyl groups that are easily absorbent will be produced. More oriented dipoles or interfaces will increase the polarization dielectric loss, which cannot meet the requirements of low dielectric loss materials.

[0003] The preparation method of low-dielectric epoxy resin composite materials is generally through adding fillers with low dielectric constants, such as hollow glass microspheres, mesoporous silica, POSS, etc., to epoxy resin. The use of hollow glass microspheres can effectively reduce the dielectric constant of the material, but it will significantly reduce the mechanical strength of the composite material. At the same time, hollow glass microspheres are easy to break during the preparation process and cannot maintain the hollow structure well; mesoporous silica has a large specific surface area and is difficult to disperse in the resin; POSS is expensive, which increases the manufacturing cost of the material. Summary of the Invention

[0004] In response to the technical problems of low mechanical strength, difficult dispersion and high price of existing low-dielectric epoxy resin composite materials, the present invention provides a low-dielectric loss epoxy resin composite material and a preparation method thereof, which has high thermal stability, low dielectric loss and high mechanical strength.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A low dielectric loss epoxy resin composite material comprises the following raw materials in parts by weight:

[0007]

[0008] Furthermore, the viscosity of the bisphenol F epoxy resin is 2000-5000 cp.

[0009] Furthermore, the thermoplastic resin is any one of PES, polyurethane-modified epoxy and core-shell toughened particles.

[0010] Furthermore, the curing agent is micro-powder-grade dicyandiamide with a particle size of 5 to 10 μm.

[0011] Furthermore, the accelerator is any one of modified imidazole, modified urea and modified amine.

[0012] A method for preparing a low dielectric loss epoxy resin composite material comprises the following steps:

[0013] 1) Prepare the following raw materials according to the mass parts: phenol type epoxy resin, bisphenol F type epoxy resin, thermoplastic resin, bisphenol A type cyanate resin, wollastonite, curing agent, accelerator and silicon dioxide;

[0014] 2) taking 80% to 90% of the phenol-type epoxy resin from step 1), mixing it with the thermoplastic resin and bisphenol A cyanate ester resin from step 1), heating it to 120° C. to 150° C. under vacuum conditions, and stirring it for 40 to 60 minutes to obtain component 1;

[0015] 3) The remaining phenol-type epoxy resin is mixed with the bisphenol F epoxy resin and wollastonite from step 1), the temperature is raised to 100° C., stirred for 40 minutes, and then cooled to 70° C., followed by the addition of a curing agent, an accelerator, and silicon dioxide. The mixture is stirred for another 30 minutes, the mixture is removed, and then ground to obtain component 2;

[0016] 4) Mixing component 1 and component 2 at a temperature of 70° C. to 80° C. and stirring for 30 to 40 minutes to obtain a low dielectric constant epoxy resin composition;

[0017] 5) preparing a resin-impregnated film using the low dielectric constant epoxy resin composition obtained in step 4) on a coating machine;

[0018] 6) Spreading the prepared resin-impregnated film on the fiber in a prepreg machine for impregnation to obtain a prepreg;

[0019] 7) The prepreg is cut, laid on a mold, and cured using an autoclave process to obtain a composite material.

[0020] In step 6), the fiber is carbon fiber or glass fiber.

[0021] In step 7), the curing conditions are: temperature 150° C., time 60 min, and curing pressure 6 bar.

[0022] The present invention provides the following beneficial effects: The epoxy resin composite material utilizes a phenol-based epoxy resin and a bisphenol A cyanate ester resin as the main resin matrix, adds modified acicular wollastonite, and uniformly disperses it in the resin through strong shear forces. The acicular crystals, which remain even after pulverization, provide the material with high thermal stability, low dielectric loss, and high mechanical strength. Furthermore, the present invention provides a method for preparing the epoxy resin composite material with low manufacturing cost and simple process. DETAILED DESCRIPTION

[0023] The present invention will now be described in detail with reference to specific embodiments.

[0024] The present invention provides a low dielectric loss epoxy resin composite material, comprising the following raw materials in parts by weight:

[0025]

[0026]

[0027] In the present invention, the phenol type epoxy resin is a high viscosity liquid epoxy resin and is semi-solid at room temperature.

[0028] In the present invention, the viscosity of the bisphenol F epoxy resin is 2000-5000 cp.

[0029] In the present invention, the thermoplastic resin is any one of PES, polyurethane-modified epoxy and core-shell toughened particles.

[0030] In the present invention, the curing agent is micro powder grade dicyandiamide with a particle size of 5 to 10 μm.

[0031] In the present invention, the accelerator is any one of modified imidazole, modified urea and modified amine.

[0032] In the present invention, the bisphenol A cyanate ester resin is in solid state.

[0033] In the present invention, wollastonite is needle-shaped wollastonite.

[0034] The method for preparing the low dielectric loss epoxy resin composite material provided by the present invention comprises the following steps:

[0035] 1) Prepare the following raw materials in parts by mass: phenol-type epoxy resin, bisphenol F-type epoxy resin, thermoplastic resin, bisphenol A-type cyanate resin, wollastonite, curing agent, accelerator and silicon dioxide;

[0036] 2) taking 80% to 90% of the phenol-type epoxy resin from step 1), mixing it with the thermoplastic resin and bisphenol A cyanate ester resin from step 1), heating it to 120° C. to 150° C. under vacuum conditions, and stirring it for 40 to 60 minutes to obtain component 1;

[0037] 3) The remaining phenol-type epoxy resin is mixed with the bisphenol F epoxy resin and wollastonite from step 1), the temperature is raised to 100° C., stirred for 40 minutes, and then cooled to 70° C., followed by the addition of a curing agent, an accelerator, and silicon dioxide. The mixture is stirred for another 30 minutes, the mixture is removed, and then ground to obtain component 2;

[0038] 4) Mixing component 1 and component 2 at a temperature of 70° C. to 80° C. and stirring for 30 to 40 minutes to obtain a low dielectric constant epoxy resin composition;

[0039] 5) preparing a resin-impregnated film using the low dielectric constant epoxy resin composition obtained in step 4) on a coating machine;

[0040] 6) Spreading the prepared resin-impregnated film on the fiber in a prepreg machine for impregnation to obtain a prepreg;

[0041] 7) Cutting the prepreg, laying it on a mold, and curing it using an autoclave process to obtain a low dielectric loss epoxy resin composite material.

[0042] In step 6) of the present invention, the fiber is carbon fiber or glass fiber.

[0043] In step 7) of the present invention, the curing conditions are: temperature 150° C., time 60 min, and curing pressure 6 bar.

[0044] In the present invention, a low dielectric constant epoxy resin composition is first obtained, and then the composition is pre-impregnated with fibers to obtain an epoxy resin composite material. The strength of the final composite material is related to the pre-impregnated fibers, but the strength meets the strength requirements of the composite material. However, the dielectric constant of the final composite material is low.

[0045] Example 1

[0046] In this embodiment, the mass fraction of the low dielectric loss epoxy resin composite material is composed of:

[0047] 56 parts of phenol-type epoxy resin;

[0048] Bisphenol A cyanate resin: 10 parts;

[0049] Bisphenol F epoxy resin: 6 parts;

[0050] Thermoplastic resin: 7 parts;

[0051] Wollastonite: 10 parts;

[0052] Micronized dicyandiamide: 7 parts:

[0053] Modified amine accelerator: 2 parts;

[0054] Fumed silica: 2 parts.

[0055] In this embodiment, the thermoplastic resin is PES, which is a polyethersulfone resin.

[0056] In this embodiment, the viscosity of the bisphenol F epoxy resin is 2000 cp.

[0057] In this embodiment, the micro powder grade dicyandiamide has a particle size of 5 μm.

[0058] The preparation method provided in this embodiment comprises the following steps:

[0059] First, a low dielectric constant epoxy resin composition is prepared

[0060] (1) Add 50 parts of phenol-type epoxy resin, thermoplastic resin, and bisphenol A cyanate resin into a reaction kettle, heat to 130° C. under vacuum conditions, and stir for 60 minutes to obtain component 1;

[0061] (2) The remaining 6 parts of phenol-type epoxy resin, bisphenol F epoxy resin, and wollastonite were added to the reactor, heated to 100°C, stirred for 40 minutes, and then cooled to 70°C. Then, micronized dicyandiamide (particle size 5 μm), modified imidazole accelerator, and fumed silica were added. After stirring for 30 minutes, the mixture was taken out and then ground three times on a three-roll mill to obtain component 2;

[0062] (3) Component 1 and component 2 were mixed in a reaction kettle at 80° C. and stirred for 40 min to obtain a low dielectric constant epoxy resin composition.

[0063] Next, prepare the prepreg

[0064] The method for preparing the prepreg is as follows: the low dielectric constant epoxy resin composition prepared above is applied to a coating machine to prepare a resin-impregnated film; the resin-impregnated film is spread on the fiber for impregnation in the prepreg machine, and the fiber is carbon fiber T700 grade.

[0065] Finally, the composite material was prepared

[0066] The prepreg prepared above was cut, laid on a mold, and cured by an autoclave process at a curing temperature of 150° C., a time of 60 minutes, and a curing pressure of 6 bar to obtain a composite material.

[0067] Example 2

[0068] In this embodiment, the mass fraction of the low dielectric loss epoxy resin composite material is composed of:

[0069] 50 parts of phenol-type epoxy resin;

[0070] Bisphenol A cyanate ester resin: 5 parts;

[0071] Bisphenol F epoxy resin: 8 parts;

[0072] Thermoplastic resin: 10 parts;

[0073] Wollastonite: 17 parts;

[0074] Micronized dicyandiamide: 6 parts:

[0075] Modified imidazole accelerator: 2.5 parts;

[0076] Fumed silica: 1.5 parts.

[0077] In this embodiment, the thermoplastic resin is PES, which is a polyethersulfone resin.

[0078] In this embodiment, the viscosity of the bisphenol F epoxy resin is 5000 cp.

[0079] In this embodiment, the micro powder grade dicyandiamide has a particle size of 10 μm.

[0080] The preparation method provided in this embodiment comprises the following steps:

[0081] First, a low dielectric constant epoxy resin composition is prepared

[0082] (1) Add 40 parts of phenol-type epoxy resin, thermoplastic resin, and bisphenol A cyanate resin into a reaction kettle, heat to 130° C. under vacuum conditions, and stir for 60 minutes to obtain component 1;

[0083] (2) The remaining 10 parts of phenol-type epoxy resin, bisphenol F epoxy resin, and wollastonite were added to the reactor, heated to 100°C, stirred for 40 minutes, and then cooled to 70°C. Then, micronized dicyandiamide (particle size 5 μm), modified imidazole accelerator, and fumed silica were added. After stirring for 30 minutes, the mixture was taken out and then ground three times on a three-roll mill to obtain component 2.

[0084] (3) Component 1 and component 2 were mixed in a reaction kettle at 80° C. and stirred for 40 min to obtain a low dielectric constant epoxy resin composition.

[0085] Next, prepare the prepreg

[0086] The low dielectric constant epoxy resin composition prepared above is used to prepare a resin-impregnated film on a coating machine; the prepared resin-impregnated film is spread on the fiber in a prepreg machine for impregnation, and the fiber is carbon fiber T700 grade.

[0087] Finally, the composite material was prepared

[0088] The prepreg prepared above was cut, laid on a mold, and cured by an autoclave process at a curing temperature of 150° C., a time of 60 minutes, and a curing pressure of 6 bar to obtain a composite material.

[0089] Example 3

[0090] In this embodiment, the mass fraction of the low dielectric loss epoxy resin composite material is composed of:

[0091]

[0092] The thermoplastic resin is polyurethane modified epoxy.

[0093] In this embodiment, the viscosity of the bisphenol F epoxy resin is 2000 cp.

[0094] In this embodiment, the micro powder grade dicyandiamide has a particle size of 5 μm.

[0095] The preparation method provided in this embodiment comprises the following steps:

[0096] First, a low dielectric constant epoxy resin composition is prepared

[0097] (1) Add 45 parts of phenol-type epoxy resin, polyurethane-modified epoxy and bisphenol A cyanate resin into a reaction kettle, heat to 130° C. under vacuum conditions, and stir for 40 minutes to obtain component 1;

[0098] (2) The remaining 5 parts of phenol-type epoxy resin, bisphenol F epoxy resin, and wollastonite were added to the reactor, heated to 90°C, stirred for 40 minutes, and then cooled to 70°C. Then, micronized dicyandiamide (particle size 5 μm), modified urea accelerator, and fumed silica were added. After stirring for 30 minutes, the mixture was taken out and then ground three times on a three-roll mill to obtain component 2.

[0099] (3) Component 1 and component 2 were mixed in a reaction kettle at 80° C. and stirred for 40 min to obtain a low dielectric constant epoxy resin composition.

[0100] Next, prepare the prepreg

[0101] The method for preparing the prepreg comprises the following steps: (1) preparing a resin-impregnated adhesive film from the low dielectric constant epoxy resin composition prepared above on a coating machine; and (2) spreading the prepared adhesive film on a fiber for impregnation on a prepreg machine, wherein the fiber is glass fiber.

[0102] Finally, the composite material was prepared

[0103] The prepreg prepared above was cut, laid on a mold, and cured by an autoclave process at a curing temperature of 150° C., a time of 60 minutes, and a curing pressure of 6 bar to obtain a composite material.

[0104] Example 4

[0105] In this embodiment, the mass fraction of the low dielectric loss epoxy resin composite material is composed of:

[0106] 53 parts of phenol-type epoxy resin;

[0107] Bisphenol A cyanate resin: 10 parts;

[0108] Bisphenol F epoxy resin: 6 parts;

[0109] Thermoplastic resin: 8 parts;

[0110] Wollastonite: 10 parts;

[0111] Micronized dicyandiamide: 7 parts:

[0112] Modified amine accelerator: 3 parts;

[0113] Fumed silica: 3 parts.

[0114] The thermoplastic resin is a core-shell toughened particle.

[0115] In this embodiment, the viscosity of the bisphenol F epoxy resin is 2000 cp.

[0116] In this embodiment, the micro powder grade dicyandiamide has a particle size of 5 μm.

[0117] The preparation method provided in this embodiment comprises the following steps:

[0118] First, a low dielectric constant epoxy resin composition is prepared

[0119] (1) Add 40 parts of phenol-type epoxy resin, polyurethane-modified epoxy and bisphenol A cyanate resin into a reaction kettle, heat to 130° C. under vacuum conditions, and stir for 40 minutes to obtain component 1;

[0120] (2) The remaining 5 parts of phenol-type epoxy resin, bisphenol F epoxy resin, and wollastonite were added to the reactor, heated to 90°C, stirred for 40 minutes, and then cooled to 70°C. Then, micronized dicyandiamide (particle size 5 μm), modified amine accelerator, and fumed silica were added. After stirring for 30 minutes, the mixture was taken out and then ground three times on a three-roll mill to obtain component 2;

[0121] (3) Component 1 and component 2 were mixed in a reaction kettle at 80° C. and stirred for 40 min to obtain a low dielectric constant epoxy resin composition.

[0122] Next, prepare the prepreg

[0123] The method for preparing the prepreg comprises the following steps: (1) preparing a resin-impregnated adhesive film from the low dielectric constant epoxy resin composition prepared above on a coating machine; and (2) spreading the prepared adhesive film on a fiber for impregnation on a prepreg machine, wherein the fiber is glass fiber.

[0124] Finally, the composite material was prepared

[0125] The prepreg prepared above was cut, laid on a mold, and cured by an autoclave process at a curing temperature of 150° C., a time of 60 minutes, and a curing pressure of 6 bar to obtain a composite material.

[0126] Comparative Example 1

[0127] In this comparative example, the resin system composition is composed of the following parts by mass: 50 parts of phenol-type epoxy resin, 5 parts of bisphenol A-type cyanate resin, 8 parts of bisphenol F-type epoxy resin, 10 parts of thermoplastic resin (PES), 17 parts of hollow glass microspheres, 6 parts of micropowder-grade dicyandiamide, 2.5 parts of modified imidazole accelerator, and 1.5 parts of fumed silica.

[0128] The composite material was prepared by the same method as in Example 2.

[0129] Comparative Example 2

[0130] In this comparative example, the resin system composition is composed of the following parts by mass: 53 parts of phenol-type epoxy resin, 10 parts of bisphenol A cyanate ester resin, 6 parts of bisphenol F epoxy resin, 8 parts of thermoplastic resin (core-shell toughened particles), 10 parts of hollow glass microspheres, 7 parts of micropowder-grade dicyandiamide, 3 parts of modified amine accelerator, and 3 parts of fumed silica.

[0131] The composite material was prepared by the same method as in Example 4.

[0132] The properties of the composite material prepared in this example and the composite material prepared in the comparative example were tested using standard testing methods in the industry. The test results are shown in Table 1.

[0133] Table 1 Performance results of various composite materials

[0134] performance Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Tensile strength / MPa 1700 1400 510 530 1200 490 Bending strength / MPa 1200 1000 650 670 800 600 Interlaminar shear strength / MPa 65 62 58 63 60 50 Dielectric constant 2.78 2.93 2.81 2.78 3.25 2.9 Dielectric loss 0.0072 0.0085 0.0065 0.0060 0.0100 0.0074

[0135] As shown in Table 1, the composite materials prepared in Examples 1 to 4 exhibit high thermal stability, low dielectric loss, and high mechanical strength. The addition of wollastonite to the composite materials prepared in Example 2 and Comparative Example 1 enhances their performance, reduces their dielectric constant, and decreases their dielectric loss. The addition of wollastonite to the composite materials prepared in Example 4 and Comparative Example 2 enhances their performance, reduces their dielectric constant, and decreases their dielectric loss.

Claims

1. A low dielectric loss epoxy resin composite material, characterized in that: It is composed of the following raw materials in parts by mass: 56 parts of phenol-type epoxy resin; 10 parts of bisphenol A cyanate resin; 6 parts of bisphenol F epoxy resin; 7 parts of thermoplastic resin; 10 parts of wollastonite; 7 parts of micronized dicyandiamide; 2 parts of modified amine accelerator; Fumed silica: 2 parts; The thermoplastic resin is PES, which is a polyethersulfone resin; The viscosity of the bisphenol F epoxy resin is 2000cp; The particle size of the micronized dicyandiamide is 5 μm; The preparation method of the low dielectric loss epoxy resin composite material comprises the following steps: First, a low dielectric constant epoxy resin composition is prepared (1) Add 50 parts of phenol-type epoxy resin, thermoplastic resin, and bisphenol A cyanate resin into a reaction kettle, heat to 130°C under vacuum conditions, and stir for 60 minutes to obtain component 1; (2) The remaining 6 parts of phenol-type epoxy resin, bisphenol F epoxy resin, and wollastonite were added to the reactor, heated to 100°C, stirred for 40 minutes, and then cooled to 70°C. Then, micronized dicyandiamide, modified imidazole accelerator, and fumed silica were added. After stirring for 30 minutes, the mixture was taken out and then ground three times on a three-roll mill to obtain component 2. (3) Component 1 and component 2 were mixed in a reaction kettle at 80°C and stirred for 40 minutes to obtain a low dielectric constant epoxy resin composition; Next, prepare the prepreg The method for preparing the prepreg comprises: applying the low dielectric constant epoxy resin composition prepared above to a coating machine to prepare a resin-impregnated film; and applying the prepared resin-impregnated film to a fiber in a prepreg machine for impregnation, wherein the fiber is a T700 grade carbon fiber. Finally, the composite material was prepared The prepreg prepared above was cut, laid on a mold, and cured by an autoclave process at a curing temperature of 150° C., a time of 60 minutes, and a curing pressure of 6 bar to obtain a composite material.

2. A low dielectric loss epoxy resin composite material, characterized in that: It is composed of the following raw materials in parts by mass: 50 parts of phenol-type epoxy resin; 5 parts of bisphenol A cyanate resin; 8 parts of bisphenol F epoxy resin; 10 parts of thermoplastic resin; 17 parts of wollastonite; 6 parts of micronized dicyandiamide: 2.5 parts of modified imidazole accelerator; 1.5 parts of fumed silica; The thermoplastic resin is PES, which is a polyethersulfone resin; The viscosity of the bisphenol F epoxy resin is 5000cp; The micro powder grade dicyandiamide has a particle size of 10 μm; The preparation method of the low dielectric loss epoxy resin composite material comprises the following steps: First, a low dielectric constant epoxy resin composition is prepared (1) Add 40 parts of phenol-type epoxy resin, thermoplastic resin, and bisphenol A cyanate resin into a reaction kettle, heat to 130°C under vacuum conditions, and stir for 60 minutes to obtain component 1; (2) The remaining 10 parts of phenol-type epoxy resin, bisphenol F epoxy resin, and wollastonite were added to the reactor, heated to 100°C, stirred for 40 minutes, and then cooled to 70°C. Then, micronized dicyandiamide, modified imidazole accelerator, and fumed silica were added. After stirring for 30 minutes, the mixture was taken out and then ground three times on a three-roll mill to obtain component 2. (3) Component 1 and component 2 were mixed in a reaction kettle at 80°C and stirred for 40 minutes to obtain a low dielectric constant epoxy resin composition; Next, prepare the prepreg The low dielectric constant epoxy resin composition prepared above is applied to a coating machine to prepare a resin-impregnated film; the resin-impregnated film is spread on a prepreg machine to impregnate the fiber, which is a T700 grade carbon fiber; Finally, the composite material was prepared The prepreg prepared above was cut, laid on a mold, and cured by an autoclave process at a curing temperature of 150° C., a time of 60 minutes, and a curing pressure of 6 bar to obtain a composite material.

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