A sizing for carbon fiber prepreg, a method of making, and a method of making a prepreg

Abstract

This invention discloses a slurry for carbon fiber prepreg, its preparation method, and the prepreg preparation method. The slurry is prepared by weight using 1%-50% thermoplastic resin powder, 50%-99% slurry dispersion medium, 0.01%-5% surfactant, 0.01%-5% defoamer, 0.01%-20% viscosity modifier, 0.01%-5% modifier A, and 5%-50% modifier B. The carbon fiber prepreg is then prepared using a powder suspension method. This method effectively improves the interfacial compatibility between carbon fiber and thermoplastic resin, as well as the interfacial bonding ability between layers of the carbon fiber thermoplastic composite material. Furthermore, this invention improves the toughness and interfacial bonding strength of the thermoplastic prepreg with relatively few additives, thereby enhancing the overall performance of the prepreg.

Description

Technical Field

[0001] This invention relates to the field of additives for carbon fiber prepregs and their preparation, and in particular to a slurry for carbon fiber prepregs, a preparation method thereof, and a method for preparing the prepreg. Background Technology

[0002] Carbon fiber reinforced thermoplastic composites have excellent properties that can replace metals, and are lightweight, high-toughness, and easy to process, so their applications cover almost all sectors of the national economy.

[0003] The improvement of carbon fiber reinforced composite material performance depends on the improvement of interfacial bonding strength. Common resin-based composite materials can be structurally divided into three phases: the matrix phase, the reinforcement phase, and the interfacial phase. The interface is a crucial microstructure in composite materials, acting as a "bridge" connecting the reinforcement and the matrix, and also a stress transfer mechanism, significantly influencing the physical and mechanical properties of the composite material. The properties of the interface directly affect various mechanical properties of the composite material, especially interlaminar shear, fracture, and impact resistance. Therefore, with the development of composite material science and applications, the interface and its mechanical behavior are receiving increasing attention.

[0004] For reinforced thermoplastic composites, since the matrix itself lacks reactive functional groups, it is difficult to form good chemical bonds with the fibers, so the interfacial bonding problem becomes more important. Summary of the Invention

[0005] Purpose of the invention: In order to solve the problems existing in the prior art, the present invention provides a slurry for carbon fiber prepreg, a preparation method thereof, and a method for preparing the prepreg, which effectively enhances the bonding strength of the interface of thermoplastic carbon fiber prepreg, thereby improving its comprehensive performance.

[0006] Technical solution: To achieve the above objectives, the present invention may adopt the following technical solution:

[0007] A slurry for carbon fiber prepreg, characterized by comprising, by weight, the following raw materials: 1%-50% thermoplastic resin powder, 50%-99% slurry dispersion medium, 0.01%-5% surfactant, 0.01%-5% defoamer, 0.01%-20% viscosity modifier, 0.01%-5% modifier A, and 5%-50% modifier B.

[0008] Furthermore, the density of the thermoplastic resin powder is greater than 1 g / cm³. 3 The average powder particle size D50 is less than 50 μm.

[0009] Furthermore, the thermoplastic resin powder is selected from one or more of nylon PA, polycarbonate PC, polyphenylene sulfide PPS, polyether ether ketone PEEK, and polyetherimide PEI.

[0010] Furthermore, the slurry dispersion medium is deionized water.

[0011] Furthermore, in order to improve the compatibility of the thermoplastic powder with water, the surfactant is one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, polyoxyethylene stearate, polyoxyethylene octanol ether, and hexadecyltrimethylammonium bromide.

[0012] Furthermore, in order to eliminate air bubbles in the slurry, the defoamer is one or more of DOW Corning 1520, QX930T, and other polysiloxane defoamers.

[0013] Furthermore, in order to improve the compatibility between the fiber and the resin, the modified material A is specifically selected from... Prime 4983R Emulsion 48625M1 One or more of the following: Emulsion91735, HydrosizeTM U6-01, HydrosizeTM U2022, HydrosizeTM PP2-01, HydrosizeTM HP3-02, HydrosizeTM HP-1632, HydrolubeTM 723, FGLASSTM X90, and FGLASSTM X48.

[0014] Furthermore, the modified material A is specifically... Prime 4983R, HydrosizeTM PP2-01, HydrosizeTM U6-01.

[0015] More preferably, the modified material A is HydrosizeTM U6-01.

[0016] To improve the toughness and interlaminar shear strength of thermoplastic prepregs, the modified material B is specifically selected from one or more of the following: carbon nanotubes, halloysite nanotubes, polyether ester elastomers, polyvinyl alcohol, polyether sulfone (PES), polyether ketone (PEK), and nano-silica particles.

[0017] Furthermore, the modified material B is more preferably carbon nanotubes, polyethersulfone (PES), or polyetherketone (PEK), with the modified material B specifically being polyetherketone (PEK).

[0018] The synergistic effect mechanism of modified material A and modified material B is as follows:

[0019] Common resin-based composite materials can be structurally divided into three phases: the matrix phase, the reinforcement phase, and the interface phase. The interface phase acts as a link and stress transfer bridge between the reinforcement and the resin matrix. Generally speaking, the contact and wetting process between the thermoplastic resin matrix and the reinforcing fibers is difficult due to the relatively weak polarity of thermoplastic resins, resulting in poor compatibility between the resin and the fibers.

[0020] This application improves the interfacial compatibility between carbon fibers and resin by adding the aforementioned modified material A. The modified material B selected in this application mainly consists of two types of materials: nanomaterials and high-toughness materials similar to the resin. During the melt extrusion of the prepreg, modified material B can achieve nanoscale mixing with the resin matrix, ensuring thorough mixing of the reinforcing material B with the resin matrix. When stress is generated in the prepreg (in fiber-reinforced composites, the stress is mainly borne by the fibers), the stress on the fibers can be transferred to the resin through the interfacial layer (modified material A). The resin matrix will deform accordingly after being subjected to stress. If the deformation of the resin is not synchronized with the deformation of the fibers under stress, phase separation will occur between the reinforcing fibers and the resin matrix, resulting in fiber-resin delamination. The cracks generated by delamination become stress concentration points. Under continuous stress, fracture propagates from the concentration point, significantly reducing the final performance of the composite material. By adding modifier B, the matrix resin can be transformed from a brittle material to a tough material. Consequently, when subjected to stress, the resin deformation (elongation at break) is greater than or equal to the fiber deformation, thus preventing the fiber from delaminating with the matrix resin.

[0021] The present invention also discloses a method for preparing the above-mentioned slurry for carbon fiber prepreg, comprising the following steps:

[0022] (1) Weigh out deionized water, surfactant, defoamer and viscosity modifier according to the ratio, turn on mechanical stirring, and stir at a speed of 400-1000 r / min; after dissolution, take a sample for viscosity test to determine whether the viscosity of the slurry is within the range of 0.1-50 cps;

[0023] (2) Weigh out the resin powder, modified material A and modified material B according to the ratio; add them slowly in batches to (1) to make the materials and water fully mixed; the stirring time should be at least 6 hours and the stirring speed should be 400-1000 r / min to obtain the required slurry.

[0024] The present invention also discloses a method for preparing carbon fiber prepreg using the above-mentioned slurry, specifically using a powder suspension method. The carbon fiber is a conventional domestic carbon fiber, specifically one or more of SYT-49S, HF-10m, SYT-45S, and HF-30m.

[0025] Furthermore, the preparation method steps are as follows:

[0026] (1) Transfer the prepared slurry to the impregnation tank for later use;

[0027] (2) Select good carbon fiber and install yarn bundles according to the production width requirements, installing 6-72 carbon fibers;

[0028] (3) The carbon fiber is heat-treated in a high-temperature infrared oven to remove the epoxy sizing agent on the fiber surface.

[0029] (4) The carbon fiber is dipped in the impregnation tank to absorb the slurry, and the volatile substances in the slurry are removed by the infrared drying oven. Finally, the resin powder is impregnated into the fiber by heating and extrusion through the mold to obtain the prepreg.

[0030] Beneficial Effects: This invention has the following advantages: 1) It effectively improves the interfacial compatibility between carbon fiber and thermoplastic resin, as well as the interfacial bonding ability between layers of the carbon fiber thermoplastic composite material. 2) By adding fewer additives, it enhances the toughness of the thermoplastic prepreg and strengthens the interfacial bonding strength, thereby improving the overall performance of the prepreg. 3) The powder suspension preparation method disperses the additives in water in a dissolved or suspended manner, allowing the fibers to uniformly carry away the corresponding materials when adsorbing the slurry, further improving the overall performance of the prepreg. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments:

[0032] The sources of raw materials used in the examples and comparative examples are as follows:

[0033] Thermoplastics such as nylon PA, polycarbonate PC, polyphenylene sulfide PPS, polyether ether ketone PEEK, and polyether imide PEI are from Shanghai Yuyan Industrial Co., Ltd., while sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, polyoxyethylene stearate, polyoxyethylene octanol ether, and hexadecyltrimethylammonium bromide are from Shanghai Youdao Aoba Chemical Co., Ltd.

[0034] DOW Corning 1520, QX930T polysiloxane defoamer, sodium carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyacrylamide (PAM) are from Guangzhou Ledong Trading Co., Ltd.

[0035] Prime 4983R Emuls ion 48625M1, Emuls ion 91735, HydrosizeTM U6-01, HydrosizeTM U2022, HydrosizeTM PP2-01, HydrosizeTM HP3-02, HydrosizeTM HP-1632, HydrolubeTM 723, FGLASSTM X90, and FGLASSTM X48 are from Michaelmen New Materials Co., Ltd.

[0036] Carbon nanotubes, halloysite nanotubes, polyether ester elastomers, polyvinyl alcohol, polyethersulfone (PES), polyether ketone (PEK), and nano silica particles are from Shanghai Guangyun Industrial Co., Ltd.

[0037] SYT-49S and SYT-45S are from Zhongfu Shenying Carbon Fiber Co., Ltd.

[0038] HF-10m and HF-30m are from Jiangsu Hengshen Co., Ltd.

[0039] The preparation methods of the slurries in Examples 1-3 and Comparative Examples 1-2 are as follows:

[0040] Example 1:

[0041] (1) Weigh 75kg of deionized water, 1.0kg of surfactant, 0.5kg of defoamer and 2.0kg of viscosity modifier, add them to the dispersion tank, and turn on the mechanical stirring at a speed of 700r / min.

[0042] The surfactant is sodium dodecyl sulfonate; the defoamer is DOW Corning 1520; and the viscosity modifier is sodium carboxymethyl cellulose.

[0043] (2) Add 25 kg of resin powder, 0.5 kg of modifier A, and 10 kg of modifier B slowly in batches to (1), mixing them thoroughly with water for 12 hours. The resin powder is polyphenylene sulfide; the modifier A is... Prime 4983R, with modified material B being polyethersulfone (PES).

[0044] Example 2:

[0045] (1) Weigh 80kg of deionized water, 0.9kg of surfactant, 0.45kg of defoamer and 1.8kg of viscosity modifier, add them to the dispersion tank, and turn on the mechanical stirring at a speed of 700r / min.

[0046] The surfactant is sodium dodecylbenzenesulfonate; the defoamer is QX930T; and the viscosity modifier is polyacrylamide (PAM).

[0047] (2) Add 20 kg of resin powder, 0.4 kg of modifier A, and 9 kg of modifier B slowly in batches to (1) and mix them thoroughly with water for 12 hours. The resin powder is polyphenylene sulfide; the modifier A is HydrosizeTMU6-01 and the modifier B is polyetherketone (PEK).

[0048] Example 3:

[0049] (1) Weigh 70kg of deionized water, 1.2kg of surfactant, 0.6kg of defoamer and 2.2kg of viscosity modifier, add them to the dispersion tank, and turn on the mechanical stirring at a speed of 700r / min.

[0050] The surfactant is polyoxyethylene octyl ether; the defoamer is QX930T; and the viscosity modifier is polyvinyl alcohol (PVA).

[0051] (2) Add 30kg of resin powder, 0.6kg of modifier A, and 11kg of modifier B slowly in batches to (1) and mix them thoroughly with water for 12 hours. The resin powder is polyphenylene sulfide; the modifier A is HydrosizeTMU6-01 and the modifier B is polyetherketone (PEK).

[0052] Comparative Example 1:

[0053] Other implementation methods are basically the same as in Example 1, except that no modified material B is added in step (2).

[0054] Comparative Example 2:

[0055] Other implementation methods are basically the same as in Example 1, except that modified material A and modified material B are not added in step (2).

[0056] Comparative Example 3:

[0057] Other implementation methods are basically the same as in Example 1, except that no modified material A is added in step (2).

[0058] The method for preparing thermoplastic prepregs using the slurries prepared in Example 1 and Comparative Examples 1-3 is as follows:

[0059] (1) Transfer the prepared slurry (Example 1, Comparative Examples 1-3) to the impregnation tank for later use.

[0060] (2) Select SYT49S to produce wide (150mm) prepreg, which requires the installation of 33 carbon fibers.

[0061] (3) The carbon fiber is heat-treated in a high-temperature infrared oven to remove the epoxy sizing agent on the fiber surface.

[0062] (4) The carbon fiber is dipped in the impregnation tank to absorb the slurry, and the volatile substances in the slurry are removed by the infrared drying oven. Finally, the resin powder is impregnated into the fiber by heating and extrusion through the mold to obtain the prepreg.

[0063] (5) The prepreg obtained above is pressed into a board by molding process to facilitate interlaminar shear performance testing. The thickness of the laminate is 4mm.

[0064] Test methods and data:

[0065] Currently, methods for characterizing the interfacial strength of composite materials can be broadly classified into three categories: macroscopic composite material experiments, microcomposite material experiments, and in-situ composite material experiments. Among these, macroscopic experimental methods evaluate the bonding state between the fiber and matrix interface through the macroscopic properties of composite materials, with interlaminar shear (short beam shear) being the most commonly used.

[0066] The carbon fiber prepreg prepared from the slurries prepared in Example 1 and Comparative Examples 1-2 using the above-described preparation method was first unidirectionally laid up, and then the prepreg was transferred to a compression molding press for compression molding. Test strips of the corresponding specifications and dimensions were prepared according to ISO 14130-1997 standard, and interlaminar shear strength was tested. Tensile strength test standard: ISO 527-5.

[0067] The specific test results are shown in Table 1:

[0068] Table 1 Comparison of test results for prepregs prepared in the examples and comparative examples

[0069]

[0070] As can be seen from the data in Table 1, compared with Comparative Example 2, which did not add either Modifier A or Modifier B, the interlaminar shear strength of Examples 1 and Comparative Examples 1 and 3 was significantly improved. The interlaminar shear strength of Example 1 was 12.6% higher than that of Comparative Example 1. Compared with Comparative Examples 1-3, the tensile strength of the prepreg laminate in Examples 1-3 was improved by more than 10%, with Example 3 showing the best performance in all aspects (Explanation: Fiber and resin are two different substances with poor interfacial compatibility. Through interfacial modification, the interfacial bonding strength was improved, thereby improving the tensile properties). The above data indicate that the addition of Modifier A and Modifier B can improve the interfacial bonding strength of carbon fiber thermoplastic composites to a certain extent, and the combined use of the two has a better effect.

[0071] It should be noted that the above specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. After reading the present invention, any modifications of the present invention by those skilled in the art in various equivalent forms fall within the scope defined by the appended claims.

Claims

1. A slurry for carbon fiber prepreg, characterized in that... The raw materials, by weight, include the following: thermoplastic resin powder 1%-50%, slurry dispersion medium 50%-99%, surfactant 0.01%-5%, defoamer 0.01%-5%, viscosity modifier 0.01%-20%, modifier A 0.01%-5%, and modifier B 5%-50%. The thermoplastic resin powder is polyphenylene sulfide (PPS); The modified material A is at least one selected from Hydrosize™ U6-01, Michem® Prime 4983R or Hydrosize™ PP2-01; the modified material B is at least one selected from polyetherketone (PEK) or polyethersulfone (PES).

2. The slurry for carbon fiber prepreg according to claim 1, characterized in that: The thermoplastic resin powder has a density greater than 1 g / cm³. 3 The average powder particle size D50 is less than 50 μm.

3. The slurry for carbon fiber prepreg according to claim 1, characterized in that: The slurry dispersion medium is deionized water.

4. The slurry for carbon fiber prepreg according to claim 1, characterized in that: The surfactant is one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, polyoxyethylene stearate, polyoxyethylene octanol ether, and hexadecyltrimethylammonium bromide.

5. The slurry for carbon fiber prepreg according to claim 1, characterized in that: The defoamer is one or more of the following polysiloxane defoamers: DOWCorning 1520 and QX930T.

6. A method for preparing the slurry for carbon fiber prepreg as described in claim 1, characterized in that... Includes the following steps: (1) Weigh out deionized water, surfactant, defoamer and viscosity modifier according to the ratio, turn on mechanical stirring, and stir at a speed of 400-1000 r / min; after dissolution, take a sample for viscosity test to determine whether the viscosity of the slurry is within the range of 0.1-50 cps; (2) Weigh out the resin powder, modified material A and modified material B according to the ratio; add them slowly in batches to (1) so that the materials are fully mixed with water; the stirring time should be at least 6 hours and the stirring speed should be 400-1000 r / min to obtain the required slurry.

7. A method for preparing a carbon fiber prepreg using the slurry of claim 1, characterized in that... The carbon fiber is prepared by powder suspension method, and the carbon fiber is a domestic conventional carbon fiber, specifically one or two of SYT-49S and SYT-45S.

8. The method for preparing carbon fiber prepreg according to claim 7, characterized in that: (1) Transfer the prepared slurry to the impregnation tank for later use; (2) Select good carbon fiber and install yarn bundles according to the production width requirements, installing 6-72 carbon fibers; (3) The carbon fiber is heat-treated in a high-temperature infrared oven to remove the epoxy sizing agent on the fiber surface; (4) The carbon fiber is soaked in the slurry in the impregnation tank, and the volatile substances in the slurry are removed by the infrared drying oven. Finally, the resin powder is impregnated into the fiber by heating and extrusion through the mold to obtain the prepreg.

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