A resin composition for laminated plates and a method for preparing 2D laminated carbon-carbon plates

Abstract

The present invention provides a resin composition for laminated plates and a method for preparing 2D laminated carbon-carbon plates, belonging to the technical field of carbon-carbon composite materials. The resin composition comprises the following components in parts by mass: 100 parts of phenolic resin; 5-20 parts of epoxy resin E51; 5-10 parts of carbon fiber powder; the room temperature viscosity of the phenolic resin is 5000-6500 cp; the particle size of the carbon fiber powder is 100-400 mesh. This resin formulation uses phenolic resin as the main component, and simultaneously adds 5%-20% by mass of epoxy resin E51 based on the phenolic resin, and 5%-10% by mass of carbon fiber powder based on the phenolic resin. Experiments show that by impregnating carbon cloth with the improved resin formulation in the examples of the present invention, the flexural strength of the prepared 2D laminated carbon-carbon plates can be increased by 425%, and the tensile strength can be increased by 200%; the product yield can be increased from 10% to 98%, which is conducive to application and large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon-carbon composite materials, and particularly relates to a resin composition for laminated plates and a method for preparing 2D laminated carbon-carbon plates. Background Art

[0002] Carbon-carbon composite materials are a new type of material applicable to high-temperature scenarios. Under the protection of inert gas, their maximum service temperature is above 2000°C. 2D-structured carbon-carbon composite materials are widely used in the photovoltaic and semiconductor industries due to their small deformation and high density. Its main preparation process flow is: carbon fiber roving → 2D woven carbon cloth → phenolic resin prepreg → carbon cloth cutting → carbon cloth layering → hot pressing and curing → high-temperature carbonization → densification → high-temperature purification at 2200°C. Among them, the densification process includes: there are a large number of pores in the carbon-carbon composite material. Generally, phenolic resin is used to fill the pores, and then high-temperature treatment is carried out to convert non-carbon elements into small-molecule gases and discharge them, leaving only carbon elements.

[0003] The traditional process mainly uses phenolic resin to impregnate carbon cloth. However, during the curing process of phenolic resin, as the temperature rises, the viscosity will drop from 6000 cp to 500 - 1000 cp, resulting in a large loss of resin and a decrease in resin content (usually 20% - 30%); in the later carbonization treatment, the laminated plate is prone to delamination, and the delamination probability is usually 80%, resulting in a low yield. The 20% that is not delaminated will also cause delamination during the machining process due to insufficient strength, and its bending strength is low, unable to meet customer requirements. Summary of the Invention

[0004] In view of this, the present invention provides a resin composition for laminated plates and a method for preparing 2D laminated carbon-carbon plates. By using the resin formula provided by the present invention, 2D laminated carbon-carbon plates with higher strength can be prepared, and the yield is improved.

[0005] The present invention provides a resin composition for laminated plates, comprising the following components in parts by mass:

[0006] 100 parts of phenolic resin;

[0007] 5 - 20 parts of epoxy resin E51;

[0008] 5 - 10 parts of carbon fiber powder;

[0009] The phenolic resin has a room temperature viscosity of 5000 - 6500 cp; the carbon fiber powder has a particle size of 100 - 400 mesh.

[0010] In some embodiments, the mass part of the epoxy resin E51 is 8 - 12 parts.

[0011] In some embodiments, the particle size of the carbon fiber powder is 200-300 mesh.

[0012] In some embodiments, the resin composition further comprises 5-10 parts by mass of silica powder.

[0013] In some embodiments, the particle size of the silica powder is 100-400 mesh.

[0014] The present invention provides a method for preparing a 2D laminated carbon-carbon plate, comprising the following steps:

[0015] Using the resin composition described above, impregnate a plurality of 2D-structured carbon cloths; the impregnated carbon cloths are successively subjected to layering, hot pressing and curing, high-temperature carbonization, densification and purification to obtain a 2D laminated carbon-carbon plate.

[0016] In some embodiments, the grammage of the 2D-structured carbon cloth is 360-420 g / m 2 。

[0017] In some embodiments, the temperature of the hot pressing and curing is 90-150 °C; the temperature of the high-temperature carbonization is 700-900 °C.

[0018] In some embodiments, the densification includes: impregnating the carbon-carbon material after high-temperature carbonization in liquid phenolic resin, and obtaining a densified carbon-carbon material through high-pressure heating and curing and high-temperature treatment.

[0019] In some embodiments, the temperature of the purification is above 2000 °C.

[0020] Compared with the prior art, the embodiments of the present invention provide a resin formulation for manufacturing a 2D laminated carbon-carbon plate, which takes phenolic resin (room temperature viscosity: 5000-6500 cp) as the main component, and simultaneously adds epoxy resin E51 with a mass of 5%-20% of the phenolic resin, and carbon fiber powder (solid, particle size: 100-400 mesh) with a mass of 5%-10% of the phenolic resin. Experiments show that by impregnating the carbon cloth with the improved resin formulation in the embodiments of the present invention, the bending strength of the prepared 2D laminated carbon-carbon plate can be increased by 425%, and the tensile strength can be increased by 200%; the product yield can be increased from 10% to 98%, which is beneficial to application and large-scale production. Detailed Embodiments

[0021] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be described in detail below with reference to specific embodiments. The description of this part is only exemplary and explanatory, and should not have any limiting effect on the protection scope of the present invention.

[0022] The present invention provides a resin composition for laminated plates, comprising the following components in parts by mass:

[0023] 100 parts of phenolic resin;

[0024] 5 - 20 parts of epoxy resin E51;

[0025] 5 - 10 parts of carbon fiber powder;

[0026] The room - temperature viscosity of the phenolic resin is 5000 - 6500 cp; the particle size of the carbon fiber powder is 100 - 400 mesh.

[0027] By using the resin formulation provided by the present invention, a 2D laminated carbon - carbon plate with relatively high strength can be prepared, and the yield rate can be increased.

[0028] The resin composition provided by the embodiment of the present invention can be used as a prepreg, which is mainly used for the carbon cloth impregnation process in the preparation of 2D laminated carbon - carbon plates; the resin composition includes phenolic resin, and this component can bond with carbon cloth to form a composite material. Because of its high high - temperature residual carbon and low price, it is usually the preferred resin for carbon - carbon composite materials. Phenolic resin is usually a high - molecular product obtained by polymerizing phenol or its homologues and formaldehyde; the room - temperature viscosity of the phenolic resin described in the embodiment of the present invention is 5000 - 6500 cp, preferably phenolic resin with a viscosity of 6000 cp, and commercially available products can be used, such as phenolic resin with a solid content of 80% - 85%. Centipoise (cP) is the unit of dynamic viscosity; dynamic viscosity represents the measure of the internal friction force when a liquid flows under a certain shear stress, and its value is the ratio of the shear stress applied to the flowing liquid to the shear rate, which is expressed in Pa·s in the International System of Units and is customarily expressed in cP. The room temperature herein is the normal temperature well - known to those skilled in the art, such as between 15 and 30 °C.

[0029] Relative to 100 parts by mass of phenolic resin, the resin composition described in the embodiment of the present invention includes 5 - 20 parts of epoxy resin E51, preferably 6 - 16 parts by mass, such as 10 parts, 12 parts, 14 parts, 15 parts, and more preferably 8 - 12 parts. Epoxy resin is a resin containing more than two epoxy groups. Bisphenol A - type epoxy resin is the most widely used, and it also includes various types such as alicyclic epoxy resins.

[0030] The epoxy equivalent of the epoxy resin can be the mass in grams of the epoxy resin containing 1 mol of epoxy groups, and the epoxy value can be defined as the number of moles of epoxy groups contained in 100 g of the epoxy resin. The epoxy resin E51, as a curing agent for the phenolic resin, can appropriately increase the curing rate of the phenolic resin. The higher the epoxy equivalent of the epoxy resin, the faster the reaction with the phenolic resin. In the embodiments of the present application, an appropriate amount of epoxy resin E51 is selected. Although the epoxy equivalent of E51 is low, the reaction with the phenolic resin can be improved by increasing the amount of E51 used, so as to achieve the purpose of reducing resin loss. Secondly, the epoxy resin E51 has a low viscosity (30-100 cp) at room temperature, which is convenient for mixing with the phenolic resin. In addition, compared with other epoxy resins with a high epoxy equivalent, the commercially available price of the epoxy resin E51 is affordable.

[0031] In some embodiments of the present application, the specific amount of the epoxy resin E51 was also screened and tested, and the results are as follows. According to Table 1, the curing time of the finished product of this material is preferably 40-50 min, which is not only convenient for operation, but also can relatively save working hours and is beneficial to application.

[0032] Table 1: Results of the screening test for the amount of epoxy resin

[0033] Curing time of the product at 135°C (min) Phenolic resin 80-120 Phenolic resin + 5% epoxy resin 50-60 Phenolic resin + 10% epoxy resin 40-50 Phenolic resin + 15% epoxy resin 20-30 Phenolic resin + 20% epoxy resin 15-20

[0034] Moreover, the resin composition in the embodiments of the present invention includes 5-10 parts by mass of carbon fiber powder with a particle size of 100-400 mesh. The carbon fiber powder is a carbon fiber solid powder with a micron-level particle size. Its main function is to increase the surface roughness of the carbon cloth and further improve the bonding effect between the phenolic resin and the carbon cloth. The particle size of the carbon fiber powder is preferably 200-300 mesh, and it can be powder particles ground from carbon-carbon products. If its particle size is too large, it will affect the structure of the carbon fiber (forming pits), and if the particle size is too small, the effect of increasing the surface roughness of the raw silk is not obvious, and it is difficult to synergistically improve the bonding effect.

[0035] In addition, the resin composition in the embodiments of the present invention preferably further includes: 5-10 parts by mass of silica powder (based on the phenolic resin, the mass percentage of the silica powder is 5%-10%). Because silicon dioxide (SiO2) will lose oxygen atoms during the high-temperature treatment process, the extra silicon atoms will form silicon carbide (SiC) with the carbon atoms of the carbon cloth. This compound with stronger chemical bond energy is beneficial to improving the mechanical properties of products such as laminates. Preferably, the particle size of the silica powder is 100-400 mesh.

[0036] Aiming at the problems of delamination, insufficient strength and low yield rate of 2D laminated carbon-carbon plates, the embodiments of the present invention provide a method for preparing 2D laminated carbon-carbon plates, including the following steps: using the resin composition described above to impregnate a certain number of carbon cloths with 2D structure; the impregnated carbon cloths are successively subjected to layering, hot pressing and curing, high-temperature carbonization, densification and purification to obtain 2D laminated carbon-carbon plates.

[0037] In the embodiments of the present invention, a loom is used to weave the raw filaments of carbon fiber (model T700) into carbon cloths with 2D structure (the grammage of the carbon cloth is preferably 360g - 420g / m 2 ); according to the needs of customers, the carbon cloths are cut into the sizes required by customers (usually the length is greater than 1.5 meters and the width is greater than 1 meter).

[0038] At the same time, in the phenolic resin described above, the embodiments of the present invention can add epoxy resin E51 and carbon fiber powder with a mesh size of 100 - 400, and preferably add silica powder in proportion to mix and obtain a prepreg. The formula content of the resin composition of the prepreg is as described above and will not be elaborated here one by one.

[0039] In the embodiments of the present invention, a certain number of carbon cloths with 2D structure are impregnated with the prepared resin prepreg to prepare for curing and forming. The impregnation process is mainly brushing, and the material ratio range is 450g / m 2 -650g / m 2 . After impregnation, the embodiments of the present invention perform carbon cloth layering: according to the thickness required by customers, a certain number of impregnated carbon cloths are stacked layer by layer and laid parallel on a flat mold. Usually, the thickness of a single layer of carbon cloth is 0.35 - 0.37mm.

[0040] In the embodiments of the present invention, the carbon cloth is cured and shaped by hot pressing and curing. The process includes: placing the mold with the above carbon cloth on a flat hot press, through preheating in the early stage (usually 90°C, 60min), and pressure application and temperature increase for layer-by-layer curing in the later stage. The pressure range of this thermal curing can be 5MPa - 8MPa; finally, it is naturally cooled to room temperature and taken out to obtain a carbon cloth resin cured product. Among them, the temperature of pressure application and temperature increase in the later stage is usually 130 - 150°C, and the operation time can be 120min.

[0041] After obtaining the carbon cloth resin cured product, the embodiment of the present invention performs high-temperature carbonization treatment on it to exclude non-carbon elements; the temperature of the high-temperature carbonization is preferably 700-900 °C, more preferably 800 °C. Specifically, the densification after carbonization includes: impregnating the carbon-carbon material after high-temperature carbonization in liquid phenolic resin, and obtaining a densified carbon-carbon material through high-pressure heating and curing and high-temperature treatment (high-temperature treatment at 800-900 °C is required, preferably 850 °C). Finally, through high-temperature purification at more than 2000 °C, non-carbon elements are further removed to obtain a finished 2D laminated carbon-carbon plate.

[0042] In the embodiment of the present invention, the densification can use liquid phenolic resin (viscosity of 100-300 cp) to fill the pores, and the involved impregnation process is an ordinary process in the art, and there are no special restrictions in the present invention. For example, liquid phenolic resin is injected under a pressure of 2 Mpa. The embodiment of the present invention performs performance tests on the obtained finished 2D laminated carbon-carbon plate. Compared with the products of the original process, its flexural strength is increased by 425%, and its tensile strength is increased by 200%; the product is not easily delaminated, and the yield rate can be increased from 10% to 98%, which is conducive to application and large-scale production.

[0043] To further illustrate the present invention, it will be described in detail below through examples. All experimental raw materials in the following examples of the present invention can be purchased from the market or prepared according to the conventional preparation methods well-known to those skilled in the art. Among them, the percentage of raw materials in the examples represents the mass percentage.

[0044] Example 1

[0045] 2D woven carbon cloth: The raw filaments of carbon fiber (model T700) are woven into a 2D-structured carbon cloth by a loom, and the grammage of the carbon cloth is 400 g / m 2 (generally 0.96 kg / layer in weight); Size: length greater than 1.5 meters, width greater than 1 meter, and the unified size is 2000*1200 mm.

[0046] Resin prepreg formulation: Use phenolic resin (Shengquan, PF9501B, viscosity 6000 cp), add 5% epoxy resin based on the amount of phenolic resin and 10% 200-mesh carbon powder based on the amount of phenolic resin; the resin content is 30%-40%.

[0047] Pre-impregnation: Brush and pre-impregnate the prepared resin prepreg on multiple 2D carbon cloths, and the material ratio is 450 g / m 2 -650 g / m 2 (the amount of phenolic resin is generally 1.5 times the weight of the carbon cloth) to prepare for curing and forming.

[0048] Layup: Stack a certain number of pre-impregnated carbon cloths layer by layer on a flat mold, and the thickness of a single layer of carbon cloth is 0.36 mm.

[0049] Curing: Place the above-mentioned mold on a flat hot press. Through preheating (90°C, 60 min) and subsequent pressure and temperature curing (150°C, 120 min), and finally cool it naturally to room temperature, then take out the cured product; the pressure for thermal curing is 6 MPa - 7 MPa;

[0050] Carbonization: Carbonize the cured product at 800°C to remove non-carbon elements;

[0051] Densification: Immerse the carbonized product in liquid phenolic resin (Shengquan, PF9701, viscosity 100 to 300 cp), and inject the resin into the pores of the carbon-carbon product by means of high pressure (2 MPa). Then raise the temperature to 180°C to cure the resin, and then treat it at 850°C at high temperature to remove non-carbon elements.

[0052] High-temperature purification: Further remove non-carbon elements by applying a high temperature above 2000°C to obtain a finished 2D laminated carbon-carbon plate.

[0053] Examples 2 - 4

[0054] The preparation process is the same as that of Example 1, except that in addition to phenolic resin, 10% of the amount of phenolic resin of epoxy resin and 10% of the amount of phenolic resin of 400-mesh carbon powder are added; 10% of the amount of phenolic resin of epoxy resin and 10% of the amount of phenolic resin of 300-mesh carbon powder are added; 10% of the amount of phenolic resin of epoxy resin and 10% of the amount of phenolic resin of 100-mesh carbon powder are added.

[0055] The resin loss ratios during curing in Examples 2 - 4 are 35 - 40%, 30 - 35%, and 10 - 20% respectively

[0056] Example 5

[0057] The preparation process is the same as that of Example 1, except that in addition to phenolic resin, 15% of the amount of phenolic resin of epoxy resin and 5% of the amount of phenolic resin of 200-mesh carbon powder are added.

[0058] The resin loss ratio during curing in Example 5 is 30 - 35%.

[0059] Example 6

[0060] The preparation process is the same as that of Example 1, except that in addition to phenolic resin, 10% of the amount of phenolic resin of epoxy resin, 10% of the amount of phenolic resin of 200-mesh carbon powder, and 10% of the amount of phenolic resin of silica are added.

[0061] Comparative Example 1

[0062] The preparation process of the 2D laminated carbon-carbon plate is the same as that of Example 1, except that the prepreg is only phenolic resin; the resin loss ratio during curing is 70-80%.

[0063] Comparative Example 2

[0064] The preparation process of the 2D laminated carbon-carbon plate is the same as that of Example 1, except that the prepreg is phenolic resin + epoxy resin E51 which is 10% of the amount of phenolic resin; the resin loss ratio during curing is 50-60%.

[0065] Comparative Examples 3-9

[0066] The preparation process of the 2D laminated carbon-carbon plate is the same as that of Example 1, except that the prepreg is phenolic resin and carbon powder which is 10% of the amount of phenolic resin, and the particle sizes of the carbon powder are nanoscale, 1000 mesh (about 13 microns), 800 mesh (about 15 microns), 600 mesh (about 23 microns), 400 mesh (about 38 microns), 200 mesh (about 74 microns), 100 mesh (about 150 microns) in sequence.

[0067] The resin loss ratios during curing of Comparative Examples 3-9 are 70-80%, 65-70%, 65-70%, 65-70%, 55-60%, 50-55%, 40-50% respectively.

[0068] Comparative Example 10

[0069] The preparation process of the 2D laminated carbon-carbon plate is the same as that of Example 1, except that the prepreg is phenolic resin, epoxy resin E51 which is 10% of the amount of phenolic resin and 600-mesh carbon powder which is 10% of the amount of phenolic resin; the resin loss ratio during curing is 40-50%.

[0070] Performance tests were carried out on the products obtained in the examples, and the results are as follows.

[0071] Table 2 Product performance of the examples

[0072]

[0073]

[0074] Note: The measurement method of the resin loss ratio during curing includes:

[0075] Let the amount (mass) of phenolic resin be a, the solid content be w, and the amount of carbon cloth be b; the mass of the product after curing is c;

[0076] Then the resin loss ratio = [a - (c - b)] ÷ (w / a) × 100%;

[0077] If other substances (carbon powder, silicon dioxide, or epoxy resin (solid content 100%)) are incorporated into the phenolic resin, and the content ratio of other substances to phenolic resin is f:1;

[0078] Then the resin loss ratio = [a - (c - b)*(1 - f)] ÷ w / a × 100%;

[0079] During the experiment, record the usage amounts of phenolic resin, carbon cloth, and carbon powder, epoxy resin, and silicon dioxide, and the resin loss ratio can be calculated.

[0080] From the above examples and comparative experiments, it can be seen that carbon powder at the nanoscale does not improve the bleeding situation. Carbon powder with a particle size of 600 - 1000 mesh can reduce resin loss, but its influence degree cannot be distinguished in the laboratory. Carbon powder within the range of 100 - 400 mesh has an obvious influence on the resin loss situation. As the particle size of the carbon powder increases, the resin loss is less. In the embodiments of the present invention, through the action of epoxy resin E51 and carbon powder, the amount of phenolic resin loss is even less. Mixing 100-mesh carbon powder with phenolic resin can reduce the resin loss ratio by about 30%. Mixing epoxy resin together can further reduce the resin loss amount by about 30%. Considering the actual situation of the experiment, in production, it is preferably phenolic resin + 200 - 300-mesh carbon powder + 10% epoxy resin.

[0081] Regarding the usage amount of carbon powder, 10% (mass fraction) is preferred because when it is less than 10%, the reduction of resin loss is not obvious, and too much usage will make the resin into a paste, which is not conducive to the resin impregnating the carbon cloth.

[0082] In summary, the resin composition for manufacturing 2D laminated carbon-carbon plates described in the embodiments of the present invention mainly uses phenolic resin, and at the same time adds epoxy resin E51 with a mass of 5% - 20% of the phenolic resin, and carbon fiber powder (particle size: 100 - 400 mesh) with a mass of 5% - 10% of the phenolic resin, and preferably adds silicon dioxide. Experiments show that by pre-impregnating carbon cloth with the improved resin formula in the embodiments of the present invention, the flexural strength of the prepared 2D laminated carbon-carbon plates can be increased by 425%, and the tensile strength can be increased by 200%; the product yield can be increased from 10% to 98%.

[0083] The description of the above examples is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the technical solutions and claims of the present invention.

Claims

1. A method for preparing a 2D laminated carbon-carbon plate, characterized in that, Including the following steps: A resin composition is used to pre-impregnate a certain number of carbon cloths with a 2D structure, and the grammage of the carbon cloth with a 2D structure is 360 - 420 g / m 2 ; the pre-impregnated carbon cloth is successively subjected to layering, hot pressing and curing, high-temperature carbonization, and densification. The temperature of the high-temperature carbonization is 700 - 900 °C; the densification includes: impregnating the carbon-carbon material after high-temperature carbonization in liquid phenolic resin with a viscosity of 100 - 300 cp, and through high-pressure heating and curing and high-temperature treatment at 800 - 900 °C, a densified carbon-carbon material is obtained; after purification, a 2D laminated carbon-carbon plate is obtained; The resin composition comprises components in the following parts by mass: 100 parts of phenolic resin; 5 - 20 parts of epoxy resin E51; 5 - 10 parts of carbon fiber powder; The phenolic resin has a room temperature viscosity of 5000 - 6500 cp; the particle size of the carbon fiber powder is 100 - 400 mesh; The resin composition further comprises 5 - 10 parts of silica powder, and the particle size of the silica powder is 100 - 400 mesh.

2. The method according to claim 1, wherein The mass parts of the epoxy resin E51 are 8 - 12 parts.

3. The method according to claim 1, characterized in that, The particle size of the carbon fiber powder is 200 - 300 mesh.

4. The method according to claim 1, wherein The temperature of the hot pressing and curing is 90 - 150 °C.

5. The method according to any one of claims 1 to 4, characterized in that The temperature of the high-temperature treatment for densification is 850 °C.

6. The method according to claim 5, wherein The temperature of the purification is above 2000 °C.

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