A demoulding method for high temperature resistant composite material

Abstract

The present invention discloses a demoulding method for a high-temperature resistant composite material, which includes the following steps: spraying two molds for the first time with a demoulding agent containing ceramic powder, and obtaining two molds with sprayed surfaces after standing; spraying the sprayed surfaces of the two molds for the second time with a demoulding agent containing polytetrafluoroethylene powder, and obtaining two spare molds after standing again; placing a composite precursor material between the two spare molds for hot pressing, so that the sprayed surfaces of the two spare molds are in contact with the composite precursor material; demoulding the hot-pressed material to obtain a high-temperature resistant composite material. The present invention solves the problem of surface damage of the composite material by combining two demoulding agents. Therefore, the composite spraying method of first spraying a demoulding agent containing ceramic powder and then spraying a demoulding agent containing polytetrafluoroethylene powder will make the demoulding effect of carbon fiber reinforced polyetheretherketone composite material very ideal.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material demoulding, in particular to a demoulding method for high-temperature resistant composite material. Background Art

[0002] The demolding effect of composite materials affects the composite's surface. While effective demolding methods yield a composite with an intact, defect-free surface, poor methods can create numerous surface defects, which negatively impact the composite. Composite materials consist of two phases: reinforcing fibers and a polymer matrix. The resin matrix possesses many properties, one of which is excellent adhesion. Even with a perfectly smooth mold surface, the composite product and the mold will adhere. Without a mold release agent, separating the composite product from the mold is difficult. Therefore, an effective mold release material is essential for a smooth demolding process. Two common release materials are release agents and release films.

[0003] Release films prevent adhesion between auxiliary materials and composite parts, allowing glue to flow and working in conjunction with the release agent. Release films primarily include perfluoroalkoxyethylene film and polytetrafluoroethylene film. Fabric release materials can be divided into porous and non-porous materials. Porous films are suitable for removing excess polymer matrix material or for degassing during the molding process.

[0004] There are two types of release agents: paste release agents and liquid release agents. When processing and manufacturing composite materials, the type of resin base material, the curing mold material and the curing temperature determine the type of release material. The contamination of the composite surface by the release agent should also be considered.

[0005] The processing temperature of carbon fiber-reinforced polyetheretherketone (PEEK) composites is generally around 400°C. At this temperature, common release films and many release agents become ineffective. For carbon fiber-reinforced polyetheretherketone (PEEK) composites, release agents containing ceramic particles are often used. However, using release agents containing only ceramic particles is not particularly effective. Using release agents containing only ceramic powder can cause small defects to appear on the composite surface.

[0006] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0007] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a demoulding method for high-temperature resistant composite materials, aiming to solve the problem that surface defects may occur in the demoulding process of the existing high-temperature resistant composite materials.

[0008] The technical solutions of the present invention are as follows:

[0009] A method for demoulding a high-temperature resistant composite material, comprising the steps of:

[0010] The two molds are sprayed for the first time using a release agent containing ceramic powder, and after standing still, two molds with sprayed surfaces are obtained;

[0011] The sprayed surfaces of the two molds are sprayed for a second time using a release agent containing polytetrafluoroethylene powder, and then left to stand again to obtain two spare molds;

[0012] Placing the composite precursor material between two spare molds for hot pressing, wherein the sprayed surfaces of the two spare molds are in contact with the composite precursor material, and the temperature of the hot pressing treatment is greater than or equal to 400° C.;

[0013] The material subjected to the heat pressing treatment is demoulded to obtain a high temperature resistant composite material.

[0014] In the demoulding method of the high-temperature resistant composite material, the demoulding agent containing ceramic powder further comprises a dispersant unsaturated polyamine amide, a surface additive polysiloxane, and a solvent acetone.

[0015] In the demoulding method of the high-temperature resistant composite material, the ceramic powder is one or more of boron nitride powder, silicon nitride powder, zirconium oxide powder and aluminum oxide powder.

[0016] In the demoulding method of the high-temperature resistant composite material, the mesh size of the ceramic powder is 6000-7000 mesh.

[0017] In the demoulding method of the high-temperature resistant composite material, the demoulding agent containing polytetrafluoroethylene powder further comprises a dispersant unsaturated polyamine amide, a surface additive polysiloxane, and a solvent isohexane.

[0018] In the demoulding method of the high-temperature resistant composite material, the particle size of the polytetrafluoroethylene powder is 500-1000 nm.

[0019] The demoulding method of the high-temperature resistant composite material, wherein the composite precursor material is composed of laid carbon fibers and polyetheretherketone film.

[0020] Beneficial effects: The present invention sprays a release agent containing polytetrafluoroethylene powder on the mold after spraying the release agent containing ceramic powder on the mold. This method of combining the two release agents solves the problem of damage to the surface of the composite material very well. The two release agents basically form a structure without too many gaps on the surface of the mold. The polytetrafluoroethylene powder basically fills the gaps between the boron nitride powders. The molten composite material basically cannot contact the upper and lower surfaces of the mold through the gaps, nor will it adhere to the upper and lower steel plates of the mold and make demolding difficult. Therefore, the composite spraying method of first spraying a release agent containing ceramic powder and then spraying a release agent containing polytetrafluoroethylene powder will make the demolding effect of carbon fiber reinforced polyetheretherketone composite materials very ideal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of a demoulding method for a high-temperature resistant composite material.

[0022] Figure 2 This is a microscopic morphology of the sprayed surface of the spare mold in Example 1 of the present invention.

[0023] Figure 3 This is a physical picture of the composite material in Example 1 of the present invention.

[0024] Figure 4 This is a microscopic morphology of the sprayed surface of the spare mold in Comparative Example 1 of the present invention.

[0025] Figure 5 This is a physical picture of the composite material in Comparative Example 1 of the present invention.

[0026] Figure 6 This is a microscopic morphology of the sprayed surface of the spare mold in Comparative Example 2 of the present invention.

[0027] Figure 7 This is a physical picture of the composite material in Example 2 of the present invention. DETAILED DESCRIPTION

[0028] The present invention provides a demoulding method for a high-temperature resistant composite material. To make the purpose, technical solution, and effects of the present invention more clear and explicit, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention.

[0029] See also Figure 1 , Figure 1 A flow chart of a preferred embodiment of a demoulding method for a high-temperature resistant composite material provided by the present invention is shown in the figure, which includes the following steps:

[0030] S10, spraying the two molds for the first time using a release agent containing ceramic powder, and then leaving them to stand to obtain two molds with sprayed surfaces;

[0031] S20, spraying the sprayed surfaces of the two molds for a second time using a release agent containing polytetrafluoroethylene powder, and letting them stand again to obtain two spare molds;

[0032] S30, placing the composite precursor material between two spare molds for hot pressing, wherein the sprayed surfaces of the two spare molds are in contact with the composite precursor material, and the temperature of the hot pressing is greater than or equal to 400° C.;

[0033] S50, demoulding the material that has been subjected to the heat pressing treatment to obtain a high-temperature resistant composite material.

[0034] Specifically, in this embodiment, a release agent containing ceramic powder is sprayed on the mold, followed by a release agent containing polytetrafluoroethylene powder. This combination of two release agents creates a structure with essentially no gaps on the mold surface. The polytetrafluoroethylene powder essentially fills the gaps between the ceramic powders, preventing the molten composite material from passing through these gaps and contacting the upper and lower surfaces of the mold. Furthermore, the molten composite material does not adhere to the upper and lower steel plates of the mold, hindering demolding. Therefore, this combined spraying method of first spraying the ceramic powder release agent and then the polytetrafluoroethylene powder release agent results in highly effective demolding of the high-temperature-resistant composite material.

[0035] In some embodiments, the release agent containing ceramic powder further includes an unsaturated polyamine amide dispersant, polysiloxane as a surface enhancer, and acetone as a solvent. In this embodiment, the ceramic powder is one or more of, but not limited to, boron nitride powder, silicon nitride powder, zirconium oxide powder, and aluminum oxide powder; the ceramic powder has a mesh size of 6000-7000.

[0036] In some specific embodiments, the release agent containing ceramic powder is composed of 90-95% solvent component and 5-10% non-solvent component by weight, wherein the solvent component is acetone, and the non-solvent component includes 94-98wt% ceramic powder, 1-3wt% unsaturated polyamine amide and 1-3wt% polysiloxane by weight.

[0037] In some embodiments, the release agent containing polytetrafluoroethylene powder further comprises a dispersant unsaturated polyamine amide, a surface additive polysiloxane, and a solvent isohexane. In this embodiment, the particle size of the polytetrafluoroethylene powder is 500-1000 nm.

[0038] In some specific embodiments, the release agent containing polytetrafluoroethylene powder is composed of 90-95% by weight of a solvent component and 5-10% by weight of a non-solvent component, wherein the solvent component is isohexane, and the non-solvent component includes 94-98 wt % of polytetrafluoroethylene powder, 1-3 wt % of an unsaturated polyamine amide, and 1-3 wt % of a polysiloxane.

[0039] In some embodiments, the composite precursor material is composed of laid carbon fibers and polyetheretherketone films, but is not limited thereto.

[0040] The present invention will be further explained below by means of specific embodiments:

[0041] Example 1

[0042] A method for demoulding a high-temperature resistant composite material, comprising the steps of:

[0043] Select two pieces of 304 stainless steel plates of the same size as the mold. The thickness of the 304 stainless steel plates is 2mm, the length is 150mm, and the width is 130mm.

[0044] A release agent containing boron nitride powder is prepared, which is composed of 90-95% solvent component and 5-10% non-solvent component, wherein the solvent component is acetone, and the non-solvent component includes, by weight percentage, 96wt% boron nitride powder, 2wt% unsaturated polyamine amide, and 2wt% polysiloxane, and the mesh size of the boron nitride is 6500 mesh;

[0045] A release agent containing polytetrafluoroethylene powder is prepared, which is composed of 90-95% of a solvent component and 5-10% of a non-solvent component, wherein the solvent component is isohexane, and the non-solvent component includes, by weight percentage, 96% by weight of polytetrafluoroethylene powder, 2% by weight of an unsaturated polyamine amide, and 2% by weight of a polysiloxane, and the particle size of the polytetrafluoroethylene powder is 1000 nm;

[0046] The first spraying of the two molds was performed using a release agent containing ceramic powder, with a spray flow rate of 1cm 3 / s, for every 100cm of mold 2 The spraying time for the area is 5s. After standing for 2min, two molds with sprayed surfaces are obtained;

[0047] Use a release agent containing polytetrafluoroethylene powder to spray the sprayed surfaces of the two molds for the second time, and the spray flow rate is 1cm 3 / s, for every 100cm of mold 2 The spraying time of the area is 10s. After standing for 1min again, two spare molds are obtained. The microscopic morphology of the sprayed surface of the spare mold is as follows Figure 2 As shown;

[0048] The laid carbon fiber and polyetheretherketone film are placed between two spare molds and subjected to hot pressing at 400°C, with the sprayed surfaces of the two spare molds in contact with the laid carbon fiber and polyetheretherketone film;

[0049] The material after heat pressing is demoulded to obtain Figure 3 High temperature resistant composite material shown.

[0050] Comparative Example 1

[0051] A method for demoulding a composite material, comprising the steps of:

[0052] Select two stainless steel plates of the same size as the mold. The thickness of the stainless steel plates is 2mm, the length is 150mm, and the width is 130mm.

[0053] A release agent containing polytetrafluoroethylene powder is prepared, which is composed of 90-95% of a solvent component and 5-10% of a non-solvent component, wherein the solvent component is isohexane, and the non-solvent component includes, by weight percentage, 96% by weight of polytetrafluoroethylene powder, 2% by weight of an unsaturated polyamine amide, and 2% by weight of a polysiloxane, and the particle size of the polytetrafluoroethylene powder is 1000 nm;

[0054] The two molds were sprayed with a release agent containing polytetrafluoroethylene powder, and the spray flow rate was 1cm 3 / s, and two spare molds were obtained after standing for 2 minutes. The microscopic morphology of the sprayed surface of the spare mold is shown in FIG. Figure 4 As shown;

[0055] Placing the laid carbon fiber and polyetheretherketone film between two spare molds and performing a hot pressing process at 400° C., wherein the sprayed surfaces of the two spare molds are in contact with the laid carbon fiber and polyetheretherketone film;

[0056] The material after heat pressing is demoulded to obtain Figure 5 The composite material shown.

[0057] Comparative Example 2

[0058] A method for demoulding a composite material, comprising the steps of:

[0059] Select two stainless steel plates of the same size as the mold. The thickness of the stainless steel plates is 2mm, the length is 150mm, and the width is 130mm.

[0060] A release agent containing boron nitride powder is prepared, which is composed of 90-95% solvent component and 5-10% non-solvent component, wherein the solvent component is acetone, and the non-solvent component includes, by weight percentage, 96wt% boron nitride powder, 2wt% unsaturated polyamine amide, and 2wt% polysiloxane, and the mesh size of the boron nitride is 6500 mesh;

[0061] The two molds were sprayed with a release agent containing boron nitride, and the spray flow rate was 1cm 3 / s, and two spare molds were obtained after standing for 2 minutes. The microscopic morphology of the sprayed surface of the spare mold is shown in FIG. Figure 6 As shown;

[0062] Placing the laid carbon fiber and polyetheretherketone film between two spare molds and performing a hot pressing process at 400° C., wherein the sprayed surfaces of the two spare molds are in contact with the laid carbon fiber and polyetheretherketone film;

[0063] The material after heat pressing is demoulded to obtain Figure 7 The composite material shown.

[0064] By comparison Figure 3 、 Figure 5 and Figure 7 From the actual pictures of the composite materials shown, it can be found that if the mold is only sprayed with a release agent containing polytetrafluoroethylene powder, it will not be able to be demolded; if the mold is only sprayed with a release agent containing boron nitride powder, some damage will appear on the surface of the composite material; if the mold is composite sprayed, the surface of the composite material is basically not damaged. The demolding effect of the composite spraying is significantly improved compared with the demolding effect of spraying only a release agent containing boron nitride powder.

[0065] from Figure 2 The microscopic morphology of the spare mold shown in the figure shows that the combined spraying method of a release agent containing PTFE powder and a release agent containing boron nitride powder significantly improves the release agent's micromorphology. The two release agents essentially form a structure with few gaps on the surface of the stainless steel plate. The PTFE powder essentially fills the gaps between the boron nitride powder, preventing the molten PEEK polymer from passing through these gaps and contacting the upper and lower stainless steel plates of the mold. This prevents adhesion and hinders demolding. Therefore, the combined spraying method of first spraying the release agent containing boron nitride powder and then spraying the release agent containing PTFE powder results in highly ideal demolding results for carbon fiber-reinforced PEEK composites.

[0066] from Figure 4From the microscopic morphology of the spare mold shown, it can be seen that the release agent on the surface of the stainless steel plate is uneven and unevenly distributed. This is because the polytetrafluoroethylene powder will agglomerate and enrich, which makes it impossible for polytetrafluoroethylene to form a uniform thin layer. This also explains why spraying only the release agent containing polytetrafluoroethylene powder will result in unsatisfactory demoulding effect.

[0067] from Figure 6 The microscopic morphology of the spare mold shows that the boron nitride powder has almost completely covered the surface of the stainless steel plate. However, it can also be seen that the boron nitride powder is flaky, with gaps between the flakes. The molten polyetheretherketone polymer may pass through these gaps and bond to the upper and lower stainless steel plates of the mold. The gaps between the boron nitride flakes and the boron nitride powder also explain why composite materials prepared by hot pressing have surface defects after demolding. Surface defects in composite materials can adversely affect their performance. These defects expose the carbon fibers to air, preventing the polyetheretherketone polymer from protecting them.

[0068] In summary, the present invention sprays a release agent containing ceramic powder on the mold and then sprays a release agent containing polytetrafluoroethylene powder on the mold. This method of combining the two release agents solves the problem of damage to the surface of the composite material very well. The two release agents basically form a structure without too many gaps on the surface of the mold. The polytetrafluoroethylene powder basically fills the gaps between the boron nitride powders. The molten composite material basically cannot contact the upper and lower surfaces of the mold through the gaps, nor will it adhere to the upper and lower steel plates of the mold and make demolding difficult. Therefore, the composite spraying method of first spraying a release agent containing ceramic powder and then spraying a release agent containing polytetrafluoroethylene powder will make the demolding effect of carbon fiber reinforced polyetheretherketone composite materials very ideal.

[0069] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A demoulding method for a high temperature resistant composite material, characterized in that: Including steps: The two molds are sprayed for the first time using a release agent containing ceramic powder, and then left to stand to obtain two molds with sprayed surfaces; the release agent containing ceramic powder also includes a dispersant unsaturated polyamine amide, a surface additive polysiloxane, and a solvent acetone; The sprayed surfaces of the two molds are sprayed a second time using a release agent containing polytetrafluoroethylene powder, and the molds are allowed to stand for a second time to obtain two spare molds. The release agent containing polytetrafluoroethylene powder further includes a dispersant unsaturated polyamine amide, a surface additive polysiloxane, and a solvent isohexane. Placing a composite precursor material between two spare molds for hot pressing, wherein the sprayed surfaces of the two spare molds are in contact with the composite precursor material, and the temperature of the hot pressing treatment is greater than or equal to 400° C. The composite precursor material is composed of laid carbon fibers and polyetheretherketone film; The material subjected to the heat pressing treatment is demoulded to obtain a high temperature resistant composite material.

2. The demoulding method of the high temperature resistant composite material according to claim 1, characterized in that: The ceramic powder is one or more of boron nitride powder, silicon nitride powder, zirconium oxide powder and aluminum oxide powder.

3. The demoulding method of the high temperature resistant composite material according to claim 1, characterized in that: The mesh number of the ceramic powder is 6000-7000 mesh.

4. The demoulding method of the high temperature resistant composite material according to claim 1, characterized in that: The particle size of the polytetrafluoroethylene powder is 500-1000 nm.

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