Carbon fiber composite material protection plate as well as preparation method and application thereof

Abstract

The invention discloses a carbon fiber composite material protection plate and a preparation method and application thereof.The preparation method comprises the steps that polyacrylonitrile-based carbon fiber tows, hollow carbon balls, polyphenylene sulfide, polyetherimide, a coloring agent, a coupling agent and an antioxidant are evenly mixed according to the proportion and then melted, and a melt is formed; a screw rod of the injection molding machine can rotate to push the melt to move forwards, and the melt is kept to reach proper temperature and viscosity to reach the interior of a mold cavity; cooling and curing, opening the mold, and taking down the formed part; the carbon fiber composite material protection plate is obtained. The invention relates to application of a carbon fiber composite material protection plate, which is used for manufacturing a cabinet. The cabinet made of the carbon fiber composite material protection plate has the advantages of being light in weight, good in heat conductivity, good in electromagnetic shielding effect, low in processing cost and not prone to combustion.

Description

Technical Field

[0001] The invention relates to a carbon fiber composite material protection plate and a preparation method and application thereof. Background Art

[0002] As a metal material, aluminum alloy has good thermal conductivity and light weight. At present, in some equipment that has requirements on the weight of the whole machine, the cabinets of the power distribution system are often made of aluminum alloy materials, such as new energy vehicles, aerospace and other fields. In addition, aluminum alloy has good conductivity. When electromagnetic waves act on the aluminum alloy shell, aluminum alloy will hinder the propagation of electromagnetic waves, thereby achieving the effect of electromagnetic shielding. This is especially important for power cabinets, because power cabinets usually contain a large number of electronic equipment and wires, which will generate electromagnetic radiation when working. If they are not effectively shielded, they may interfere with the performance and stability of the equipment. However, the cabinets made of aluminum alloy materials have high costs, poor rigidity, and insufficient corrosion resistance, which has always been a problem.

[0003] Cabinets made of carbon fiber composite materials are one of the possible solutions to replace the current aluminum alloy cabinets. Carbon fiber composite cabinets are light in weight, have a high rigidity-to-weight ratio, are corrosion-resistant, and have good thermal conductivity. However, although carbon fiber is conductive, the electromagnetic shielding effect of carbon fiber composite cabinets is still insufficient. Summary of the invention

[0004] The present invention provides a cabinet made of carbon fiber composite material, which has the characteristics of light weight, good thermal conductivity, good electromagnetic shielding effect, low processing cost and non-flammability.

[0005] A carbon fiber composite material protective plate, comprising the following substances in volume ratio:

[0006] Polyacrylonitrile-based carbon fiber tow; accounting for 10%-40%;

[0007] Polyphenylene sulfide (PPS), accounting for 30-70%;

[0008] Polyetherimide (PEI), accounting for 0%-20%;

[0009] Hollow carbon spheres (HCS), accounting for 10-40%;

[0010] Auxiliary materials, including: colorants, coupling agents, antioxidants, accounting for 0-5%.

[0011] A method for preparing a carbon fiber composite material protective plate comprises the following steps:

[0012] Step (1) Ingredients:

[0013] Weigh a certain volume of polyacrylonitrile-based carbon fiber tow, polyphenylene sulfide, polyetherimide, hollow carbon spheres, colorant, coupling agent, and antioxidant;

[0014] Step (2) loading:

[0015] The polyacrylonitrile-based carbon fiber tow and the hollow carbon sphere are uniformly mixed in proportion and loaded into barrel A;

[0016] Mix polyphenylene sulfide, polyetherimide, colorant, coupling agent and antioxidant in proportion and put them into barrel B;

[0017] Step (3) Molding:

[0018] Turn on the mold temperature controller and heat the mold for half an hour;

[0019] Heat the resin; wait for the resin to reach the set temperature before starting injection molding;

[0020] The materials in barrel A and barrel B are mixed in proportion and melted to form a melt; during this process, the screw of the injection molding machine will rotate, pushing the melt forward and maintaining the melt at an appropriate temperature and viscosity to reach the mold cavity; screw speed: 180-240rpm, screw temperature 280-350C;

[0021] Step (4) Curing and demoulding: Cool and solidify, open the mold, and remove the molded parts; repeat steps (3) and (4) to make the next batch of parts.

[0022] An application of a carbon fiber composite material protection plate is used to manufacture a cabinet. The cabinet of the present invention comprises a rectangular cabinet body with an opening on one side, the cabinet body is matched with a cover plate through a latch screw sleeve; a plurality of guide rails for inserting and fixing PCBs are arranged on the side wall inside the cabinet body, and a carbon fiber composite material protection plate is inserted on some of the guide rails; a mounting plate for connecting a plurality of reinforcing ribs is arranged on the outer side of the cabinet body in the length direction; a plurality of fixing mounting holes are arranged on the mounting plate; and a plurality of threading holes are arranged on the side wall of the cabinet body.

[0023] The present invention adopts the above technical solution and has the following advantages compared with the prior art:

[0024] 1. The present invention proposes a cabinet made of carbon fiber composite material, which has the characteristics of light weight, good thermal conductivity, low processing cost and is not easy to burn, and has good electrical conductivity and good electromagnetic shielding effect.

[0025] 2. Carbon fiber is a one-dimensional thermal conductive material. After adding carbon balls, its adsorption properties are utilized to improve the molding quality and the thermal conductivity of the composite material.

[0026] 3. Under different heat treatment conditions, the physical and chemical properties of hollow carbon spheres are different. This treatment method can effectively improve the composite effect of carbon fiber and hollow carbon spheres.

[0027] 4. By adding hollow carbon balls to the mixture of PPS / PEI and chopped carbon fibers, the molding quality of the carbon fiber composite material is improved and the weight reduction of the cabinet is ensured (the spherical filler does not cause a sharp increase in viscosity during filling and has little effect on the fluidity required during molding). The carbon fiber composite cabinet prepared by this method reduces the weight of the cabinet and improves the heat dissipation performance while ensuring the mechanical strength of the cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the temperature setting curve during the heat treatment of the hollow carbon spheres of the present invention.

[0029] Figure 2 It is a schematic diagram of the cabinet structure of the present invention.

[0030] Figure 3 It is a schematic diagram of the connection relationship between the carbon fiber composite material protection plate and the cabinet body of the present invention. DETAILED DESCRIPTION

[0031] A method for preparing a carbon fiber composite material protective plate comprises the following steps:

[0032] Step (1) Ingredients:

[0033] 1. Prepare the fiber: Cut the "polyacrylonitrile-based (PAN-based)" carbon fiber tow into lengths of 0.5mm-20mm (i.e. short-cut carbon fiber). (It can be a uniform length or a mixture of different lengths, such as a ratio of 5mm:10mm:20mm=5:3:2, refer to the carbon fiber specification: Nippon CN90, diameter 0.02-0.06mm) accounting for 10%-40%.

[0034] Carbon fiber modification:

[0035] First, put the carbon fiber into a mixed solution of (NH4)2S2O8 concentration of 150g / L and sulfuric acid concentration of 100ml / L, and stir for 30 minutes.

[0036] Then put it into a mixed solution of 50 mL / L 37% concentrated hydrochloric acid and 30 g / L SnCl2·2H2O and stir for 30 minutes.

[0037] Finally, wash in pure water.

[0038] 2. Polyphenylene sulfide (PPS), a thermoplastic resin, accounts for 30-70%. It has good fluidity and is easy to be injection molded.

[0039] 3. Polyetherimide (PEI), a thermoplastic resin, accounts for 0%-20% and has poor fluidity, but can improve the toughness and applicability of the cabinet after molding.

[0040] 4. Hollow carbon balls (HCS), (diameter 20um-100um, after modification, it has sufficient extrusion resistance, compressive strength> 2000psi, used to replace part of the end carbon fiber, which can improve the molding quality and reduce the weight of the cabinet, reference specification: EPO-0360), accounting for 10-40%. Heat treatment modification is required before use.

[0041] Heat treatment of hollow carbon spheres: vacuum heat treatment, heat to 700-900℃ at a heating rate of 10-30℃ / min, then maintain for 2-3h, and then gradually cool to room temperature at 3-5℃ / min (500-600C can be heated for a period of time and then cooled gradually. The specific heating curve is as follows: Figure 1 shown).

[0042] 5. Auxiliary materials, including: colorants, coupling agents, antioxidants, etc., accounting for 0-5%.

[0043] The above proportions are volume ratios, wherein the ratio of carbon fiber to all carbon balls is maintained at a 1:1 volume ratio.

[0044] The present invention can also add nickel-plated carbon fibers that account for 5% to 20% of the volume of all carbon fibers. (Note: the nickel-plated carbon fibers cannot be too much, which will affect the weight reduction effect).

[0045] Step (2) Loading: (Injection molding machine: UN90SKII-CIM)

[0046] The chopped carbon fibers and hollow carbon balls are uniformly mixed in proportion and loaded into barrel A;

[0047] Mix PPS / PEI resin (and colorant, coupling agent, antioxidant optional) in proportion and evenly load into barrel B;

[0048] Step (3) Molding (closing mold, filling, holding pressure):

[0049] Turn on the mold temperature controller and heat the mold for half an hour (120+ / -10 degrees);

[0050] Heat the resin (100+ / -20 degrees);

[0051] Wait for the resin to reach the set temperature before starting injection molding;

[0052] After the materials in the two barrels are mixed in proportion (UN90SKII-CIM injection molding machine features: quantitative metering, precise control of formula ratio, online mixing), they are melted to form a melt. During this process, the screw of the injection molding machine will rotate, pushing the melt forward and keeping the melt at the appropriate temperature and viscosity to reach the mold cavity. (The rotation of the screw not only helps to transport the melt, but also ensures that the resin melt and the fiber are fully mixed until they enter the mold cavity). Screw speed: 180-240rpm, screw temperature 280-350C.

[0053] The relevant parameters set during the injection molding process are as follows:

[0054] Filling stage: temperature 300+ / -20C, injection pressure 120-150MPa, injection speed: 25-45ccm / s (cubic centimeters per second).

[0055] Holding stage: holding pressure 30-50MPa, holding time 5-10 seconds.

[0056] Step (4) Curing and demoulding (cooling, opening the mold, demoulding): Cool and solidify, open the mold, and remove the molded parts. Repeat steps (3) and (4) to make the next batch of parts. Cooling time: 0.5-1 minute.

[0057] The carbon fiber composite material protective plate obtained in step (4) is post-processed:

[0058] a. Grind and trim the surface of parts as needed to achieve the required appearance and dimensional accuracy of the product.

[0059] b. Refer to the cabinet drawing and install the latch screw sleeves at the reserved holes to complete the cabinet manufacturing.

[0060]

[0061]

[0062]

[0063] like Figure 2 As shown, the cabinet prepared by using the carbon fiber composite material protection plate includes a rectangular cabinet body 1 with an opening on one side, and the cabinet body 1 is matched with the cover plate through a latch screw sleeve 2; a plurality of guide rails 3 for inserting and fixing PCBs are arranged on the side wall inside the cabinet body 1, and the carbon fiber composite material protection plate is inserted on some of the guide rails 3; a mounting plate 5 for connecting a plurality of reinforcing ribs 4 is arranged on the outer side in the length direction of the cabinet body 1; a plurality of fixing holes 6 are arranged on the mounting plate 5; and a plurality of threading holes 7 are arranged on the side wall of the cabinet body 1.

[0064] like Figure 3As shown, the present invention sets a carbon fiber composite material protection plate 9 between two circuit boards 8 to reflect the radiation back to the carbon fiber composite material for absorption. Grounding and lightning protection are set between the carbon fiber composite material protection plate 9 and the cabinet.

[0065] The latch screw sleeve of the present invention is installed after the cabinet shell is formed. When the cabinet shell is formed, a circular hole (bottom hole) slightly smaller than the outer diameter of the latch screw sleeve is reserved at the position of the latch screw sleeve. After the forming is completed, the latch screw sleeve is inserted into the bottom hole, and then the latch is pressed in to achieve a tightening effect, thereby providing sufficient thread connection strength for the subsequent installation of the cover plate.

[0066] In summary, for the carbon fiber cabinet, the present invention has made corresponding transformation and innovation in the cabinet structure, material formulation and molding process, so as to solve the current problems of carbon fiber composite materials in the manufacturing of thermal conductive cabinets.

Claims

1. A carbon fiber composite material protective plate, characterized in that Includes the following substances in volume ratios: Polyacrylonitrile-based carbon fiber tow; accounting for 10%-40%; Polyphenylene sulfide, accounting for 30-70%; Polyetherimide, accounting for 0%-20%; Hollow carbon spheres, accounting for 10-40%; Auxiliary materials, including: colorants, coupling agents, antioxidants, accounting for 0-5%.

2. A method for preparing the carbon fiber composite material protective plate according to claim 1, characterized in that The steps include: Step (1) Ingredients: Weigh a certain volume of polyacrylonitrile-based carbon fiber tow, polyphenylene sulfide, polyetherimide, hollow carbon spheres, colorant, coupling agent, and antioxidant; Step (2) loading: The polyacrylonitrile-based carbon fiber tow and the hollow carbon sphere are uniformly mixed in proportion and loaded into barrel A; Mix polyphenylene sulfide, polyetherimide, colorant, coupling agent and antioxidant in proportion and put them into barrel B; Step (3) Molding: Turn on the mold temperature controller and heat the mold for half an hour; Heat the resin; Wait for the resin to reach the set temperature before starting injection molding; The materials in barrel A and barrel B are mixed in proportion and melted to form a melt; during this process, the screw of the injection molding machine will rotate, pushing the melt forward and maintaining the melt at an appropriate temperature and viscosity to reach the mold cavity; screw speed: 180-240rpm, screw temperature 280-350C; Step (4) Curing and demoulding: Cool and solidify, open the mold, and remove the molded parts; repeat steps (3) and (4) to make the next batch of parts.

3. The method for preparing a carbon fiber composite material protective plate according to claim 2, characterized in that: The polyacrylonitrile-based carbon fiber tow is cut into short carbon fibers; the short carbon fibers are first placed in a mixed solution of (NH4)2S2O8 concentration of 150 g / L and sulfuric acid concentration of 100 ml / L, and stirred for 30 minutes; then placed in a mixed solution of 37% concentrated hydrochloric acid 50 ml / L and SnCl2·2H2O 30 g / L, and stirred for 30 minutes; finally, placed in pure water for cleaning.

4. The method for preparing a carbon fiber composite material protective plate according to claim 2, characterized in that: The hollow carbon spheres are subjected to vacuum heat treatment, the temperature is raised to 700-900°C at a heating rate of 10-30°C / min, then maintained for 2-3h, and then gradually cooled to room temperature at a rate of 3-5°C / min.

5. The method for preparing a carbon fiber composite material protective plate according to claim 2, characterized in that: The relevant parameters set during the injection molding process are as follows: Filling stage: temperature 300+ / -20C, injection pressure 120-150MPa, injection speed: 25-45ccm / s; Holding stage: holding pressure 30-50MPa, holding time 5-10 seconds.

6. The method for preparing a carbon fiber composite material protective plate according to claim 2, characterized in that: Cooling time: 0.5-1 minute.

7. Application of the carbon fiber composite material protective plate obtained by the preparation method according to claim 2, characterized in that: Used to manufacture cabinets.

8. The use of the carbon fiber composite material protection plate according to claim 7, characterized in that: The cabinet comprises a rectangular cabinet body (1) with an opening on one side, the cabinet body (1) being matched with a cover plate via a latch screw sleeve (2); a plurality of guide rails (3) for inserting and fixing a PCB are arranged on the side wall inside the cabinet body (1), and a carbon fiber composite material protection plate is inserted on some of the guide rails (3); a mounting plate (5) for connecting a plurality of reinforcing ribs (4) is arranged on the outer side in the length direction of the cabinet body (1); a plurality of fixing mounting holes (6) are arranged on the mounting plate (5); and a plurality of threading holes (7) are arranged on the side wall of the cabinet body (1).

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