A carbon fiber widening and shaping composite processing method

Abstract

The present invention relates to a carbon fiber widening and shaping composite treatment method, including carbon fiber widening, widening shaping and base film composite treatment methods. First, the continuous filament bundle carbon fiber is subjected to roller heating and extrusion treatment under constant tension to achieve widening, and after the widening is completed, a transverse hot melt wire is used to perform hot pressing and melting infiltration shaping at a certain interval, and finally a certain concentration of shaping thermoplastic sizing agent is coated on the widened fiber bundle after the hot melt fiber shaping, so as to complete the shaping composite treatment of the widened carbon fiber and effectively improve the widening and shaping of the continuous carbon fiber filaments.

Description

Technical Field

[0001] The invention belongs to the field of carbon fiber preparation, and particularly relates to a carbon fiber widening and shaping composite processing method. Background Art

[0002] The information disclosed in the background of the invention is only intended to enhance the understanding of the overall background of the invention and should not be necessarily regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Thermoplastic resin has poor fluidity when compounded with carbon fiber reinforcement. Therefore, there are problems such as poor wetting effect of the resin matrix at the fiber monofilament interface during the melt infiltration process and unstable interface bonding effect, which seriously affect the performance of the composite material interface performance, and then affect the stability of the macroscopic mechanical properties. In order to improve the hot melt composite effect of the thermoplastic resin matrix, the researchers expanded the carbon fiber and expanded the conventional continuous filament bundle carbon fiber in the width direction. This treatment method expands the monofilament carbon fiber inside the filament bundle in the width direction, so that the monofilament fibers are arranged in parallel. This method can significantly increase the contact area between the monofilament fibers inside the filament bundle and the thermoplastic molten resin, improve the melt infiltration composite effect of the resin melt and the monofilament fibers, and then improve the microscopic interface contact and bonding characteristics of the thermoplastic composite material. Traditional carbon fiber widening and shaping compounding generally completes the widening of the monofilament fiber under the action of axial tension through continuous traditional roller heating extrusion or ultrasonic vibration. This widening process needs to be completed under the action of constant axial tension. In order to ensure the widening effect of the fiber, it is necessary to perform a specific coating treatment on the surface of the continuous fiber before processing to ensure the stability of the fiber widening monofilament arrangement. If the tension is removed after the fiber is expanded, the continuous monofilament will inevitably slip and shrink, resulting in unstable monofilament arrangement, and sometimes even affecting the widening effect. Summary of the invention

[0004] In view of the above technical problems, the present invention proposes a composite method for shaping and widening carbon fiber, which adopts a comprehensive treatment method of transverse hot melt shaping and sizing film shaping after the fiber filament bundle is expanded, effectively improving the expansion and shaping of continuous carbon fiber filaments, and providing a fiber aggregate with good fiber arrangement for subsequent composite processing of thermoplastic resin-based composite materials.

[0005] In order to achieve the above object, the present invention provides the following technical solutions.

[0006] A method for widening, shaping and composite processing of carbon fiber comprises the following steps: firstly, a continuous filament bundle carbon fiber is subjected to roller heating and extrusion processing under the action of constant tension, after widening, hot-melt fiber filaments are applied in a direction perpendicular to the fiber for shaping processing, the widened bundle of carbon fiber with the hot-melt fiber filaments applied is subjected to melt infiltration shaping processing, and finally, the widened fiber bundle after hot-melt fiber shaping is coated with a shaping sizing agent to complete the shaping and composite processing of the widened carbon fiber.

[0007] The continuous carbon fiber tow used for carbon fiber widening can be any one of T300, T700, T800, T1000, M40, M55, M60, etc., and the widened fiber tow can be any different specifications such as 3K, 6K, 12K, 24K, etc.

[0008] The stretching tension of the carbon fiber filament bundle is controlled at 5-8N, the yarn spreading rate is 1-8m / min, the carbon fiber is heated in the range of 80-150°C under constant tension, and the final yarn spreading width is 3-5 times the original width of the carbon fiber filament bundle.

[0009] After the carbon fiber filament bundle is widened, hot-melt fiber filaments are horizontally applied at a certain interval along the axial length. The hot-melt fiber filaments can be selected from polyethylene, polypropylene, polystyrene, polyphenylene sulfide, polyamide, polyimide, polyether ketone, polyether ether ketone, polyethylene terephthalate, butylene terephthalate, etc. and are not limited to the above types. The type of hot-melt fiber matches or is similar to the final thermoplastic resin type.

[0010] The hot-melt fiber filaments can also be replaced by a strip-shaped hot-melt adhesive film of a certain width. The type of the hot-melt adhesive film is the same as described above. The hot-melt fiber filaments can be arranged in parallel with 1-10 fibers, or a hot-melt adhesive strip film with a thickness ranging from 0.05-2mm can be used. The width of the strip-shaped hot-melt adhesive film can be flexibly adjusted within the range of 2-5mm.

[0011] The spacing distance of the hot-melt filaments or hot-melt tape films along the fiber axis is controlled to be flexibly adjusted within 10-30 cm. The hot-melt filaments or tape films can be hot-melt treated in a variety of ways, such as single-sided arrangement of the filaments, alternating arrangement of the upper and lower surfaces, or alternating arrangement of multiple bundles of widened fibers in plain weave.

[0012] The hot melt treatment temperature of the hot melt fiber or ribbon hot melt adhesive film is based on the melt infiltration composite temperature of the hot melt resin type. The hot melt temperature is flexibly adjusted within the range of 120-300°C, and the hot melt setting time is flexibly adjusted within the range of 0.5-5 seconds. The hot melt pressure is controlled within the range of 0.5-3MPa. During the melt infiltration process, the widening tension is ensured to be applied synchronously.

[0013] After the widening fiber is subjected to a hot-melt fiber transverse interval infiltration shaping treatment, a shaping sizing agent of a certain concentration is coated on one or both sides of the fiber, and finally a shaping composite film coating is formed on the surface of the widening fiber by heating and drying.

[0014] The coating method can be selected from spray coating or dipping coating, and can be treated by continuous widening fiber one-side coating or double-sided continuous coating, wherein the spray coating pressure is controlled in the range of 0.5-2MPa, and the final spray thickness on the surface of the carbon fiber widening yarn is in the range of 0.02-0.1㎜.

[0015] The dipping coating can be carried out in a constant temperature dipping sizing tank at 40-60°C using an emulsion sizing agent of a certain concentration, and can be combined with ultrasonic equipment to improve the dipping coating effect. The sizing agent used for spraying or dipping coating can be a thermoplastic sizing emulsion with a solid content in the range of 5-20%.

[0016] The emulsion of the sizing and setting agent used can be selected from polyethylene, polypropylene, polystyrene, polyphenylene sulfide, polyamide, polyimide, polyether ketone, polyether ether ketone, polyethylene terephthalate, butylene terephthalate, etc. and is not limited to the above types of emulsion systems.

[0017] After the sizing and setting coating treatment, the drying treatment is carried out at a temperature within a range of 100-150° C. The drying time is controlled within a range of 10-30 minutes and can be flexibly adjusted according to the drying effect.

[0018] Compared with the prior art, the present invention has the following effects:

[0019] (1) The comprehensive treatment method of transverse hot melt shaping and sizing film shaping is adopted to effectively improve the expansion shaping of continuous carbon fiber filaments and make the fiber filaments well arranged.

[0020] (2) Use a thermoplastic sizing agent that matches or is similar to the hot melt wire or hot melt adhesive film. The two match each other, which is beneficial to the fiber widening and shaping, and effectively improves the heating and melting effect.

[0021] (3) The widening tension is applied synchronously during the infiltration process to avoid the shrinkage of the carbon fiber filaments during the infiltration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 It is a structural schematic diagram of the single-sided arrangement of hot-melt filaments in a carbon fiber widening and shaping composite treatment method of the present invention.

[0024] Figure 2 It is a structural schematic diagram of the alternating arrangement of the upper and lower surfaces of the strip hot melt adhesive film in a carbon fiber widening and shaping composite processing method of the present invention.

[0025] Figure 3 A schematic diagram of a structure in which multiple bundles of widened fibers of hot-melt filaments or ribbon-shaped hot-melt adhesive films are arranged alternately in a plain weave in a method for widening and shaping composite treatment of carbon fibers according to the present invention

[0026] Among them, 1-carbon fiber filament, 2-hot melt filament, 3-hot melt adhesive film. DETAILED DESCRIPTION

[0027] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0028] Example 1

[0029] like Figure 1-3 As shown in the figure, under the action of constant tension, T700 high-strength carbon fiber with a tow of 6K is used as the carbon fiber widening tow for roller heating and extrusion treatment, the widening tension is 6N, the widening rate is 3m / minute, and the heating temperature of the carbon fiber is 120°C. After the widening is completed, polyethylene fiber filaments are applied in the vertical fiber direction for shaping treatment. The applied filaments are arranged in parallel with 5 fibers, the application method is single-sided arrangement of the filaments, and the application spacing is 10cm. The carbon fiber widening tow with polyethylene fiber filaments is melt-infiltrated and shaped, and the hot melt temperature is set to 190°C, the hot melt time is 3 seconds, and the hot melt pressure is 2MPa. The widening tension is applied simultaneously during the melt infiltration process, and the final yarn width is 3 times the original width of the carbon fiber filament tow.

[0030] After the widened fiber is subjected to the hot-melt fiber transverse interval infiltration shaping treatment, a polyethylene emulsion with a solid content of 10% is sprayed on one side of the fiber, the spraying pressure is set to 1MPa, and the spraying thickness is 0.05mm. After the thermoplastic sizing agent is shaped and coated, it is dried at 120°C for 20 minutes.

[0031] Example 2

[0032] Under the action of constant tension, M55 high modulus carbon fiber with a tow of 12K is used as the carbon fiber widening tow for roller heating and extrusion treatment. The widening tension is 5N, the widening rate is 4m / minute, and the heating temperature of the carbon fiber is 130°C. After the widening is completed, polyphenylene sulfide fiber filaments are pasted in the vertical fiber direction. The pasted filaments are arranged in parallel with 6 fibers. The pasting method is that the upper and lower surfaces of the filaments are arranged alternately, and the pasting spacing is 15cm. The carbon fiber widening tow pasted with polyphenylene sulfide fiber filaments is melt-infiltrated and finalized, and the hot melt temperature is set to 260°C, the hot melt time is 4 seconds, and the hot melt pressure is 2.5MPa. The widening tension is applied simultaneously during the melt infiltration process, and the final yarn width is 4 times the original width of the carbon fiber filament tow.

[0033] After the widened fiber is treated with hot-melt fiber transverse interval melt infiltration and setting, it is dipped and coated in a sizing tank at a constant temperature of 60°C with ultrasonic equipment. The sizing agent is a polyphenylene sulfide emulsion with a solid content of 15%. After the thermoplastic sizing agent is set and coated, it is dried at 150°C for 15 minutes.

[0034] Example 3

[0035] Under the action of constant tension, T1000 high-strength carbon fiber with a tow of 24K is used as the carbon fiber widening tow for roller heating and extrusion treatment. The widening tension is 7N, the widening rate is 5m / minute, and the heating temperature of the carbon fiber is 130°C. After the widening is completed, a certain width of polyamide hot melt adhesive film is applied in the vertical fiber direction, with a thickness of 0.5mm and a width of 3mm. The application method is that multiple bundles of widened fibers are arranged alternately in plain weave, and the application spacing is 25cm. The carbon fiber widening tow with polyamide hot melt adhesive film is melt-infiltrated and shaped, and the hot melt temperature is set to 150°C, the hot melt time is 5 seconds, and the hot melt pressure is 2.5MPa. The widening tension is applied simultaneously during the melt infiltration process, and the final yarn width is 3 times the original width of the carbon fiber filament bundle.

[0036] After the widened fiber is subjected to the hot-melt fiber transverse interval infiltration shaping treatment, a polyamide emulsion with a solid content of 15% is sprayed on one side of the fiber, the spraying pressure is set to 1.5MPa, and the spraying thickness is 0.06mm. After the thermoplastic sizing agent is shaped and coated, it is dried at 100°C for 30 minutes.

[0037] Example 4

[0038] Under the action of constant tension, M60 high modulus carbon fiber with a tow of 24K is used as the carbon fiber widening tow for roller heating and extrusion treatment. The widening tension is 7N, the widening rate is 2m / minute, and the heating temperature of the carbon fiber is 140℃. After the widening is completed, a certain width of polypropylene hot melt adhesive film is applied in the vertical fiber direction, with a thickness of 0.4mm and a width of 4mm. The application method is that multiple bundles of widened fibers are arranged alternately in plain weave, and the application spacing is 20cm. The carbon fiber widening tow with polypropylene hot melt adhesive film is melt-infiltrated and shaped, and the hot melt temperature is set to 160℃, the hot melt time is 4 seconds, and the hot melt pressure is 2MPa. The widening tension is applied simultaneously during the melt infiltration process, and the final yarn width is 3 times the original width of the carbon fiber filament bundle.

[0039] After the widened fiber is treated with hot-melt fiber transverse interval infiltration and shaping, it is dipped and coated in a constant temperature immersion sizing tank at 50°C with ultrasonic equipment. The sizing agent is a polypropylene emulsion with a solid content of 15%. After the thermoplastic sizing agent is shaped and coated, it is dried at 150°C for 20 minutes.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A carbon fiber widening and shaping composite treatment method, characterized in that: The method comprises the following steps: firstly, heating and extruding the continuous filament bundle carbon fiber on a roller under the action of constant tension, applying hot-melt fiber filaments in a perpendicular fiber direction for shaping after widening, performing melt infiltration shaping on the widened fiber bundle with the hot-melt fiber filaments, and finally coating the widened fiber bundle after the hot-melt fiber shaping with a shaping sizing agent to complete the shaping and composite treatment of the widened carbon fiber; Or, the hot-melt fiber filaments are replaced by ribbon-shaped hot-melt adhesive films; The hot melt fiber filaments are arranged in parallel with 1 to 10 fibers; or the thickness of the strip hot melt adhesive film is in the range of 0.05 to 2 mm, and the width of the strip hot melt adhesive film is controlled in the range of 2 to 5 mm; The spacing distance of the hot-melt fiber filaments or ribbon-shaped hot-melt adhesive film along the fiber axis is controlled to be 10-30 cm, and the hot-melt filaments or ribbon-shaped hot-melt adhesive film are hot-melt treated by arranging the filaments on one side, alternating the upper and lower surfaces, or arranging multiple bundles of widened fiber plain weaves alternately.

2. The carbon fiber widening and shaping composite treatment method according to claim 1, characterized in that: The continuous filament bundle carbon fiber is selected from any one of T300, T700, T800, T1000, M40, M55, and M60, and its specification is selected from one of 3K, 6K, 12K, and 24K.

3. The carbon fiber widening and shaping composite treatment method according to claim 1, characterized in that: The conditions for the roller heating extrusion treatment are: the stretching tension is controlled at 5-8N, the yarn spreading rate is 1-8m / min, and the continuous filament bundle carbon fiber is heated in the range of 80-150°C under constant tension.

4. The carbon fiber widening and shaping composite treatment method according to claim 1, characterized in that: The hot-melt fiber filaments are selected from one or more of polyethylene, polypropylene, polystyrene, polyphenylene sulfide, polyamide, polyimide, polyether ketone, polyether ether ketone, polyethylene terephthalate, and butylene terephthalate.

5. The carbon fiber widening and shaping composite treatment method according to claim 1, characterized in that: The hot melt adhesive film is selected from one or more of polyethylene, polypropylene, polystyrene, polyphenylene sulfide, polyamide, polyimide, polyether ketone, polyether ether ketone, polyethylene terephthalate, and butylene terephthalate.

6. The carbon fiber widening and shaping composite treatment method according to claim 1, characterized in that: The hot melt temperature is 120-300°C, the hot melt setting time is 0.5-5 seconds, and the hot melt pressure is 0.5-3MPa.

7. The carbon fiber widening and shaping composite treatment method according to claim 1, characterized in that: Applying a shaping sizing agent on one or both sides of the surface, and forming a shaping composite film coating by heating and drying; The coating method is spraying or dipping.

8. The carbon fiber widening and shaping composite treatment method according to claim 7, characterized in that: The spraying pressure is 0.5-2MPa, and the spraying thickness is 0.02-0.1mm; the dipping is carried out in a constant temperature dipping sizing tank at 40-60°C.

9. The carbon fiber widening and shaping composite treatment method according to claim 8, characterized in that: Use ultrasonic equipment to improve the dipping coating effect.

10. The carbon fiber widening and shaping composite treatment method according to claim 1, characterized in that: The setting sizing agent is a thermoplastic sizing emulsion with a solid content of 5-20%; the thermoplastic sizing emulsion used is selected from one or more of polyethylene, polypropylene, polystyrene, polyphenylene sulfide, polyamide, polyimide, polyether ketone, polyether ether ketone, polyethylene terephthalate, and butylene terephthalate.

11. The carbon fiber widening and shaping composite treatment method according to claim 10, characterized in that: After applying the setting sizing agent, the surface is dried at 100-150°C for 10-30 minutes.

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