A grid prepreg, a high-thermal-conductivity composite grid panel and a preparation method thereof

Abstract

The application discloses a preparation method of a grid prepreg for preparing a high-thermal-conductivity grid panel, and the method comprises the following steps: obtaining high-thermal-conductivity carbon fiber yarn; and performing winding processing on the high-thermal-conductivity carbon fiber yarn based on a wet winding process to obtain the grid prepreg. The application also discloses a preparation method of a grid prepreg for preparing a grid panel, which comprises the following steps: preparing the grid prepreg based on the preparation method of the grid prepreg for preparing the grid panel; and performing vacuum hot-press forming on the stacked grid prepregs to obtain a high-thermal-conductivity composite grid panel. The application can prepare the high-thermal-conductivity grid panel with excellent thermal conductivity, avoids the risk of defects caused by processing the high-thermal-conductivity carbon fiber, has high material utilization, high automation degree, high preparation efficiency and good process stability. The application further discloses a grid prepreg and a high-thermal-conductivity composite grid panel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aerospace components, in particular to a grid prepreg, a high-thermal-conductivity composite grid panel and a preparation method thereof. BACKGROUND

[0002] Due to the miniaturization, lightweight and integration requirements of aerospace components, many heat-generating devices are integrated on a satellite-borne structure substrate. Therefore, on the one hand, the structure substrate is required to have good heat dissipation performance to timely dissipate the heat generated by the aerospace devices and ensure the stable operation of the equipment; on the other hand, the substrate is required to have good dimensional stability, i.e., low thermal expansion coefficient and high modulus characteristics.

[0003] At present, grid panels have been maturely applied to satellite-borne solar wing substrates and structural panels to further reduce the mass of the panel and improve the structural efficiency. For example, the comparative document CN 104300041 “Molding method of low-rigidity carbon fiber composite material semi-rigid solar cell array substrate” prepares a low-rigidity composite material substrate by using the grid panel weaving and bonding method. The comparative document CN 102148282A discloses an implementation method of a solar cell array substrate with a large grid panel, which is woven into a grid panel with a pitch of 6mm*6mm by using M60J high-modulus carbon fiber / epoxy resin. However, the thermal conductivity is not significantly improved, and the heat dissipation capacity of the panel and the structure is weak. SUMMARY

[0004] The present application aims to solve the problem of poor thermal conductivity of the current grid panel and weak heat dissipation capacity of the panel and the structure. The present application provides a high-thermal-conductivity composite grid panel and a preparation method of a grid prepreg thereof, which can have good thermal conductivity, as well as good material utilization rate, preparation efficiency and process stability.

[0005] To solve the above technical problems, the embodiment of the present application discloses a preparation method of a grid prepreg for preparing a high-thermal-conductivity grid panel, comprising:

[0006] obtaining high-thermal-conductivity carbon fiber yarn;

[0007] Based on the wet winding process, the high-thermal-conductivity carbon fiber yarn is wound to obtain the grid prepreg.

[0008] By using the above technical solution, the high-thermal-conductivity carbon fiber yarn is wound by the wet winding process to prepare the grid prepreg, which can avoid the risk of defects caused by high-thermal-conductivity carbon fiber weaving, has high automation degree and high material utilization rate, and provides a basis for preparing the high-thermal-conductivity grid panel.

[0009] As a specific embodiment, the high-thermal-conductivity carbon fiber yarn is wound based on the wet spiral winding process to obtain the grid prepreg, comprising:

[0010] obtaining a winding resin for winding processing;

[0011] determining winding process parameters according to parameters of the high-thermal-conductivity grid panel to be prepared from the grid prepreg;

[0012] wet-winding the high-thermal-conductivity carbon fiber yarn and the winding resin according to the winding process parameters to obtain an initial grid prepreg;

[0013] cutting the initial grid prepreg along the axial direction to obtain the grid prepreg.

[0014] As a specific embodiment, the high-thermal-conductivity carbon fiber yarn has a specification of 1K, 2K, 3K or 6K, and the axial thermal conductivity coefficient of the high-thermal-conductivity carbon fiber yarn is 400 W / m·K to 800 W / m·K.

[0015] As a specific embodiment, the winding resin includes one of an epoxy resin, a bismaleimide resin, a cyanate ester resin, a polyimide resin and a modified product of the above resin.

[0016] As a specific embodiment, the viscosity of the winding resin is 0.2 Pa·s to 1 Pa·s.

[0017] As a specific embodiment, the winding process parameters include a core mold straight cylinder segment length, a winding angle, and a number of times of back-and-forth winding, and the winding process parameters at least satisfy one of the following technical features:

[0018] L' > L;

[0019] πD > W;

[0020] α = α' + β, -90° ≤ α ≤ 90°, -45° < β < 45°, 15° < α' < 70°;

[0021] N = πDcosα' / (b + x)sin(180° - 2α');

[0022] wherein L' is the core mold straight cylinder segment length, L is the length of the grid panel, W is the width of the grid panel, b is the grid side length of the grid panel, D is the core mold diameter, α is the layering angle, α' is the winding angle, N is the number of times of back-and-forth winding, and x is the width of the high-thermal-conductivity carbon fiber yarn.

[0023] As a specific embodiment, the winding process parameters further include a winding tension, and the spiral winding tension is 0 to 20 N.

[0024] The application further discloses a grid prepreg for preparing a high-thermal-conductivity grid panel, which is prepared based on the above method for preparing the grid prepreg for preparing the grid panel.

[0025] As a specific embodiment, the fiber area density of the grid prepreg is 20-50 gsm, and the resin content is 20wt%-30wt%.

[0026] The application further discloses a preparation method of the high-thermal-conductivity composite grid panel.

[0027] The grid prepreg is obtained based on the preparation method of the grid prepreg for preparing the grid panel.

[0028] The grid prepregs are laminated and then vacuum hot-pressed to obtain the high-thermal-conductivity composite grid panel.

[0029] According to the technical scheme, the grid prepreg is prepared from the high-thermal-conductivity carbon fiber yarn through the wet winding process, so that the grid panel has excellent thermal conductivity. The preparation process avoids the risk of defects of the high-thermal-conductivity carbon fiber, has high material utilization, high automation, high preparation efficiency and good process stability.

[0030] As a specific embodiment, the grid prepreg is laminated, including:

[0031] The grid prepregs are laminated according to the set layering angle.

[0032] The laminated grid prepregs are fixed and sealed by the aluminum adhesive tape.

[0033] As a specific embodiment, the thermal conductivity of the aluminum adhesive tape is greater than 200 W / m·K.

[0034] As a specific embodiment, the vacuum hot-pressing is performed to obtain the high-thermal-conductivity composite grid panel, including:

[0035] The grid prepregs after the fixing and sealing are loaded into a vacuum bag.

[0036] The vacuum bag is vacuumized to a set vacuum pressure value, and the set vacuum pressure value is not greater than -0.095 MPa.

[0037] The grid prepregs after the vacuum loading are placed in a mold, the mold is heated to a set curing temperature, and a holding time is set, so that the winding resin contained in the high-thermal-conductivity composite grid panel is cured and formed; the set curing temperature is 120-180℃, and the set holding time is 30-90 min.

[0038] The application further discloses a high-thermal-conductivity composite grid panel, which is prepared based on the preparation method of the high-thermal-conductivity composite grid panel.

[0039] As a specific embodiment, the thickness of the high-thermal-conductivity composite grid panel is 0.2-0.5 mm, and the in-plane thermal conductivity of the high-thermal-conductivity composite grid panel is greater than 120 W / m·K. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A flow chart showing a method for preparing a grid prepreg according to an embodiment of the present application is shown.

[0041] Figure 2 A schematic diagram showing a wet winding process for preparing a grid prepreg according to an embodiment of the present application is shown.

[0042] Figure 3 A schematic diagram showing a grid prepreg after being unfolded according to an embodiment of the present application is shown.

[0043] Figure 4 A flow chart showing a method for preparing a high-thermal-conductivity composite grid panel according to an embodiment of the present application is shown.

[0044] Figure 5 A schematic diagram showing an aluminum adhesive tape edge sealing area after lamination of a grid prepreg according to an embodiment of the present application is shown.

[0045] In the figure, 1 is an initial grid prepreg, 2 is a core mold, and 3 is a high-thermal-conductivity carbon fiber yarn. DETAILED DESCRIPTION

[0046] The present application is described in detail below by way of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification. Although the description of the present application will be introduced in combination with preferred embodiments, this does not mean that the features of the present application are limited to the embodiments. On the contrary, the purpose of introducing the present application in combination with the embodiments is to cover other options or modifications that can be extended based on the claims of the present application. In order to provide a deep understanding of the present application, many specific details will be included in the following description. The present application can also be implemented without using these details. In addition, in order to avoid confusion or obscure the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0047] It should be noted that in the specification, similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0048] In order to make the purpose, technical solutions and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0049] REFERENCE Figure 1The embodiment of the present application discloses a preparation method of a grid prepreg for preparing a high-thermal-conductivity grid panel, comprising the following steps:

[0050] Step S11: Obtain high-thermal-conductivity carbon fiber yarn and winding resin for winding processing. The high-thermal-conductivity carbon fiber yarn is subjected to winding processing based on a wet winding process to obtain the grid prepreg.

[0051] Further, the specification of the high-thermal-conductivity carbon fiber yarn is 1K, 2K, 3K or 6K, and the axial thermal conductivity coefficient is 400 W / m·K-800 W / m·K.

[0052] Illustratively, the winding resin comprises one of epoxy resin, bismaleimide resin, cyanate ester resin, polyimide resin and modified products of the above resins. The viscosity of the winding resin is 0.2 Pa·s-1 Pa·s, so that the winding resin is easy to form a film on the fiber bundle, and the resin content of the grid prepreg is ensured. Specifically, the winding resin is used to orient, position and bond the fibers into one body and to transfer stress in the process of product stress. If the viscosity of the winding resin is too large, the resin cannot flow well, the fiber bundle cannot be fully infiltrated, or air bubbles are easily trapped. If the viscosity is too small, the fiber bundle cannot effectively carry the resin, which may result in that the resin content in the grid prepreg cannot meet the design requirements.

[0053] Further, the high-thermal-conductivity carbon fiber yarn is subjected to winding processing based on a wet spiral winding process to obtain the grid prepreg, comprising the following steps:

[0054] Step S12: Determine winding process parameters according to parameters of the grid panel to be prepared from the grid prepreg.

[0055] The winding process parameters comprise spiral winding straight cylinder length, size of a core mold, winding angle and number of times of back-and-forth winding. The winding process parameters at least satisfy the following one technical feature:

[0056] L' > L;

[0057] πD > W;

[0058] α = α' + β, -90° ≤ α ≤ 90°, -45° < β < 45°, 15° < α' < 70°;

[0059] N = πDcosα' / (b + x) sin (180° - 2α');

[0060] wherein L' is the length of the straight cylinder of the core mold, L is the length of the high-thermal-conductivity grid panel, W is the width of the high-thermal-conductivity grid panel, D is the diameter of the core mold, α is the set layup angle, α' is the winding angle, x is the width of the high-thermal-conductivity carbon fiber yarn (i.e. the width of the high-thermal-conductivity carbon fiber yarn during winding), b is the grid side length of the high-thermal-conductivity grid panel (illustratively, the grid side length b = 4-10 mm), and N is the number of times of back-and-forth winding.

[0061] Specifically, the laying angle is determined according to the heat dissipation requirements of each direction in the actual application scenario of the high-thermal-conductivity composite grid panel.

[0062] That is, in the present embodiment, the wet-winding process parameters of the high-thermal-conductivity carbon fiber yarn in the preparation of the grid prepreg are obtained according to the parameters of the target high-thermal-conductivity composite grid panel. For example, the size of the mandrel (including the length of the straight cylinder segment and the diameter of the mandrel) is determined according to the size of the target high-thermal-conductivity composite grid panel, and the winding angle and the number of return windings are calculated according to the layup angle and the grid size of the target high-thermal-conductivity composite grid panel. Through the correlation between the winding process parameters and the parameters of the high-thermal-conductivity grid panel, the parameter design and optimization of the high-thermal-conductivity grid panel can be achieved, and the design is strong.

[0063] Step S13: Wet-winding the high-thermal-conductivity carbon fiber yarn and the winding resin according to the winding process parameters to obtain an initial grid prepreg. For example, Figure 2 For example, a schematic diagram of the high-thermal-conductivity carbon fiber yarn 3 wound on the mandrel 2 to form the initial grid prepreg 1.

[0064] Further, after preparing the mandrel according to the obtained process parameters of the mandrel, a release paper is arranged on the mandrel to facilitate the separation of the grid prepreg from the mandrel in the later stage.

[0065] Further, the mandrel includes a straight cylinder segment and end caps at both ends, and the winding starting point of the wet-winding is equidistant from the cap hole circle. The winding tension is 0-20 N. Within this range of winding tension, it can prevent the winding tension from being too large and the fiber from being broken when the equipment is suddenly started or stopped, and it can also ensure that the fiber does not loosen during the winding process.

[0066] Step S14: cutting the initial grid prepreg along the axial direction to obtain a grid prepreg, as shown in Figure 3 For example, when the grid prepreg is cut, it can be cut along the axial direction of the mandrel. The cut grid prepreg can be stored with a film.

[0067] As described above, the technical solution of the present embodiment can avoid the risk of defects caused by weaving high-thermal-conductivity carbon fibers, has high automation degree and high material utilization rate, and makes it possible to prepare a high-thermal-conductivity grid panel. Specifically, the prepreg used to prepare the high-thermal-conductivity grid panel generally uses high-modulus or even super-high-modulus high-thermal-conductivity carbon fibers. The higher the modulus of the carbon fibers, the more difficult the weaving, and the more likely the yarn breakage during processing. Meanwhile, there are problems such as high yarn shedding and fuzzing, which makes it difficult to make good unidirectional prepreg, thereby affecting the performance of the composite material. The grid prepreg of the present embodiment is prepared by wet process winding, which can solve the problem of difficult processing and manufacturing of high-thermal-conductivity carbon fibers, and further prepare a high-thermal-conductivity grid prepreg, making it possible to prepare a high-thermal-conductivity grid panel.

[0068] The present embodiment also discloses a grid prepreg for preparing a grid panel, which is prepared based on the preparation method of the grid prepreg for preparing a grid panel. The grid prepreg provides a basic material for preparing a high-thermal-conductivity grid panel. Further, the fiber area density of the grid prepreg is 20-50 gsm, and the resin content is 20wt%-30wt%.

[0069] The present embodiment also discloses a preparation method of a high-thermal-conductivity composite material grid panel, which is prepared based on the preparation method of the grid prepreg for preparing a high-thermal-conductivity grid panel. Figure 4 , including,

[0070] Step S21: preparing a grid prepreg based on the preparation method of the grid prepreg for preparing a high-thermal-conductivity grid panel. Or directly obtaining the grid prepreg prepared by the above preparation method.

[0071] The grid prepregs are stacked and vacuum hot-pressed to obtain a high-thermal-conductivity composite material grid panel.

[0072] Specifically, the vacuum hot-pressing of the stacked grid prepregs includes the following steps:

[0073] Step S22: stacking the grid prepregs according to the set layup angle.

[0074] Further, after the grid prepregs are stacked, vacuum bagging can be performed to pre-compact the stacked grid prepregs to remove air between the grid prepregs.

[0075] Step S23: using an aluminum adhesive tape to fix and edge-seal the stacked grid prepregs, so that the stacked grid prepregs form a complete thermal-conductivity path (as shown in Figure 5 ).

[0076] Further, if vacuum bagging is used to pre-compact the laminated prepreg, after the pre-compact vacuum bag is removed, an aluminum adhesive tape is used to fix the edge of the laminated grid prepreg to ensure that the grid prepreg after laying forms a complete heat conduction path.

[0077] Further, the thermal conductivity coefficient of the aluminum-based adhesive tape is greater than 200 W / m·K.

[0078] Step S24: The grid prepreg after fixing the edge is put into a vacuum bag. The vacuum bag is vacuumed to a set vacuum pressure value. Further, the set vacuum pressure value is not greater than -0.095 MPa.

[0079] Step S25: The grid prepreg after vacuum bagging is put into a mold, the mold is heated to a set curing temperature, and the holding time is set to make the winding resin cured and formed. Further, the set curing temperature is 120-180℃, and the holding time is set at the set curing temperature for 30-90 min.

[0080] In this embodiment, the aluminum adhesive tape is used to edge the laminated grid prepreg during hot pressing, and the heat conduction path formed by the high-thermal-conductivity carbon fiber transmits the mold heat from the edge of the carbon fiber grid to the carbon fiber heat conduction network, improving the consistency and uniformity of the curing temperature and improving the forming quality.

[0081] Step S26: The grid panel after vacuum hot pressing is demolded, and the residual glue is removed to obtain a high-thermal-conductivity composite grid panel.

[0082] Through the above process steps, the high-thermal-conductivity carbon fiber and resin which are difficult to manufacture can be processed into a grid panel, directly formed, and no additional treatment is required subsequently, the process efficiency is high, the grid panel with high thermal conductivity is directly made, and the effect of improving the thermal conductivity of the grid panel is achieved. During the entire manufacturing process, the material utilization rate is high, the automation degree is high, the preparation efficiency is high, and the process stability is good.

[0083] The preparation method of the high-thermal-conductivity composite grid panel is exemplarily described by the following examples, so as to better understand the technical scheme of the present application:

[0084] The specification requirements of the target high-thermal-conductivity composite grid panel to be prepared are set as follows: length x width is 940 mm x 760 mm, the grid gap is 10±0.2 mm, and the material thermal conductivity (isotropic) is greater than 120 W / m·K.

[0085] (1) 2K high-thermal-conductivity carbon fiber yarn with an axial thermal conductivity of 600 W / m·K and a medium-temperature curing epoxy resin system are selected.

[0086] (2) Obtain winding process parameters: through formula calculation, select the mandrel diameter D = 300 mm, the mandrel straight section length L' = 760 mm, the winding angle a' = 45°, and the number of return winding N = 48.

[0087] (3) Prepare the winding mandrel and set the release paper on the mandrel.

[0088] (4) Wet spiral winding is performed on the selected high-thermal-conductivity carbon fiber yarn using a four-axis winding machine. During the winding process, the viscosity of the epoxy resin in the glue tank is adjusted to 0.5 Pa·s, and the winding tension is set to 2 N.

[0089] (5) The initial grid prepreg formed after spiral winding is cut along the mandrel axis, and the double-layer ±45° grid prepreg with a glue content of 25±2wt% and a fiber area density of 36±3 gsm is obtained by unfolding. The film is stored.

[0090] (6) Laying: stack the double-layer grid prepreg on the mold according to the ±45° layer design angle, vacuum bagging and vacuum pre-compaction. The grid prepreg stack is fixed and sealed with aluminum tape to form a complete thermal conduction path, and the vacuum bag is re-made.

[0091] (7) Vacuum hot pressing: vacuum the vacuum bag to a vacuum pressure of not more than -0.095 MPa, and maintain the vacuum pressure. Heat the mold to a resin curing temperature of 120±5℃ at a heating rate of not more than 4℃ / min, and naturally cool after holding for 90 min. When the temperature is lower than 60℃, take out the grid panel product.

[0092] (8) Demolding and post-processing: demold the grid panel and remove the residual glue to obtain a high-thermal-conductivity composite grid panel with a thermal conductivity (isotropic) of 160 W / m·K and a thickness of 0.2 mm.

[0093] The embodiment of the present application also discloses a high-thermal-conductivity composite grid panel prepared based on the preparation method of the high-thermal-conductivity composite grid panel.

[0094] As a specific embodiment, the thickness of the high-thermal-conductivity composite grid panel is 0.2-0.5 mm, and the in-plane thermal conductivity of the high-thermal-conductivity composite grid panel is greater than 120 W / m·K (isotropic). Compared with the current grid panel with a thermal conductivity of 6-7 W / m·K, the high-thermal-conductivity composite grid panel has excellent heat dissipation performance.

[0095] The thickness and thermal conductivity of the high-thermal-conductivity composite grid panel are only exemplary and do not limit the parameters of the high-thermal-conductivity composite grid panel.

[0096] While the application has been illustrated and described in connection with certain preferred embodiments thereof, it will be readily apparent to those of ordinary skill in the art that various changes in form and detail can be made therein without departing from the spirit and scope of the application. It is intended to encompass all such changes and alterations in the details thereof.

Claims

1. A method for preparing a high thermal conductivity composite material mesh panel, characterized in that, include: Obtain grid prepreg; The mesh prepreg is laminated and then vacuum hot-pressed to obtain the high thermal conductivity composite mesh panel; The method for preparing the mesh prepreg includes: Obtain high thermal conductivity carbon fiber yarn; The high thermal conductivity carbon fiber yarn is wound using a wet winding process to obtain the mesh prepreg. The process of laminating the mesh prepreg includes: The mesh prepreg is stacked according to the set layup angle; The laminated mesh prepreg was secured and sealed with aluminum tape. The thickness of the high thermal conductivity composite material mesh panel is 0.2~0.5mm, and the in-plane thermal conductivity of the high thermal conductivity composite material mesh panel is greater than 120W / m·K.

2. The preparation method according to claim 1, characterized in that, The high thermal conductivity carbon fiber yarn is wound using a wet spiral winding process to obtain the mesh prepreg, comprising: Obtain the winding resin for the winding process; Based on the parameters of the high thermal conductivity mesh panel to be prepared from the mesh prepreg, determine the winding process parameters; The high thermal conductivity carbon fiber yarn and the winding resin are wet-wound according to the winding process parameters to obtain an initial mesh prepreg. The initial mesh prepreg is cut axially to obtain the mesh prepreg.

3. The preparation method according to claim 1, characterized in that, The high thermal conductivity carbon fiber yarn has specifications of 1K, 2K, 3K or 6K, and the axial thermal conductivity of the high thermal conductivity carbon fiber yarn is 400 W / m·K ~ 800 W / m·K.

4. The preparation method according to claim 2, characterized in that, The winding resin includes one of epoxy resin, bismaleimide resin, cyanate ester resin, polyimide resin, and modified versions of the above resins.

5. The preparation method according to claim 2, characterized in that, The viscosity of the winding resin is 0.2 Pa·s to 1 Pa·s.

6. The preparation method according to claim 2, characterized in that, The winding process parameters also include winding tension, wherein the spiral winding tension is 0~20N.

7. The preparation method according to claim 1, characterized in that, The fiber areal density of the mesh prepreg is 20~50 gsm, and the resin content is 20 wt%~30 wt%.

8. The preparation method according to claim 1, characterized in that, The thermal conductivity of the aluminum tape is greater than 200 W / m·K.

9. The preparation method according to claim 1, characterized in that, The process of vacuum hot pressing to obtain the high thermal conductivity composite material mesh panel includes: The prepreg of the mesh, after being sealed at the edges, is placed into a vacuum bag; The vacuum bag is evacuated to a set vacuum pressure value, which is not greater than -0.095 MPa; The vacuum-packed mesh prepreg is placed into a mold, the mold is heated to a set curing temperature, and a set holding time is set to allow the winding resin contained in the high thermal conductivity composite mesh panel to cure and form; the set curing temperature is 120~180℃, and the set holding time is 30~90min.

10. A high thermal conductivity composite material mesh panel, characterized in that, It is prepared based on the preparation method of the high thermal conductivity composite material mesh panel as described in any one of claims 1 to 9.

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