Ultrathin carbon fiber prepreg and production process thereof

Abstract

The invention relates to the technical field of composite materials, and discloses an ultrathin carbon fiber prepreg and a production process thereof.The ultrathin carbon fiber prepreg is composed of unidirectional reinforced carbon fibers and matrix resin, the unidirectional reinforced carbon fibers are spread through a high-precision yarn spreading device, so that the fiber surface density is smaller than or equal to 20 g, the fibers are evenly distributed, and the thickness of the matrix resin is larger than or equal to 20 mm; the fiber surface density fluctuation is less than or equal to 1g. The matrix resin is a thermosetting epoxy resin composition, and the gelation time of the epoxy resin composition at 120 DEG C is less than or equal to 25 minutes, so that the problems of non-uniform carbon fiber distribution, poor surface density precision, high apparent defect ratio, excessive fiber damage and the like in the prior art are solved.

Description

Technical Field

[0001] The present application relates to the technical field of composite materials, and in particular to ultra-thin carbon fiber prepreg and a production process thereof. Background Art

[0002] In recent years, as the application of carbon fiber composite materials has become increasingly mature, carbon fiber, as a dual-use industrial material with unique properties, has been widely used in high-end fields such as aerospace and 3C electronic products. Therefore, the research and development of thinner and more precise carbon fiber prepregs is of great importance and is urgently needed by the current market.

[0003] A Chinese patent with publication number CN118617629B discloses a yarn spreading device for preparing ultra-thin high-strength medium-mode carbon fiber prepreg, comprising a support frame and two upper and lower distributed heating rollers rotatably connected to the left side of the support frame, the heating rollers are used to transport and heat the fibers, two conveying rollers are arranged on the right side of the support frame, and a lower pressing roller is arranged in the middle of the support frame; when the lower pressing roller in the present invention contacts the carbon fiber filaments below, the carbon fiber filaments will continue to sag, then the carbon fiber filaments on the right side of the two heating rollers will descend relative to the heating rollers, thereby enabling the carbon fiber filaments to form a wrap angle on the surface of the heating roller, thereby changing the point contact between the carbon fiber filaments and the heating rollers to surface contact, thereby improving the heating efficiency.

[0004] The Chinese patent with publication number CN117400447A discloses a method for preparing ultra-thin prepreg of high-strength and high-modulus carbon fiber, comprising: performing a yarn spreading process on the high-strength and high-modulus carbon fiber to obtain a flat fiber bundle, and then stacking and pressing the flat fiber bundle with a resin film placed above and below the flat fiber bundle, and fully impregnating the fiber bundle with the resin under the action of temperature and pressure, and then cooling, coating, and winding, wherein the high-strength and high-modulus carbon fiber is one of M40X, M55J, M60J and above grade carbon fibers, and the tensile modulus is greater than 377GPa. The present invention also discloses an ultra-thin prepreg of high-strength and high-modulus carbon fiber prepared by the above preparation method and its application.

[0005] At present, the ultra-thin carbon fiber prepreg prepared by the traditional carbon fiber prepreg production process has problems such as uneven carbon fiber distribution, poor surface density accuracy, high apparent defect ratio and excessive fiber damage, which cannot meet the market demand for the use of ultra-thin carbon fiber prepreg. Summary of the invention

[0006] The purpose of the present invention is to provide an ultra-thin carbon fiber prepreg and a production process thereof, aiming to solve the problems of uneven distribution of carbon fibers, poor surface density precision, high apparent defect ratio and excessive fiber damage in the prior art.

[0007] The present invention is achieved in that the ultra-thin carbon fiber prepreg is composed of unidirectional reinforced carbon fiber and matrix resin. The unidirectional reinforced carbon fiber is unfolded by a high-precision yarn spreading device so that the fiber surface density is less than or equal to 20g, the fiber distribution is uniform, and the fiber surface density fluctuation is less than or equal to 1g.

[0008] The matrix resin is a thermosetting epoxy resin composition, and the gel time of the epoxy resin composition at 120° C. is less than or equal to 25 minutes.

[0009] The unidirectional reinforced carbon fiber is one or more of T300, T700, T800, T1000, 40J, 55J, and 65J.

[0010] The width of the prepreg is less than or equal to 1005 mm.

[0011] The unidirectional reinforced carbon fiber consists of parallel and symmetrically arranged 0° direction fibers.

[0012] The production process of ultra-thin carbon fiber prepreg is characterized by comprising the following steps:

[0013] a. Use a release paper with high peeling force as the carrier;

[0014] b. coating the base resin on the release paper to form a resin film of a certain quality;

[0015] c. Paste the resin film on the release paper onto the upper and lower surfaces of the evenly spread unidirectional reinforced carbon fiber;

[0016] d. Pressurizing at room temperature to 120°C to completely impregnate the resin with the sheet-like reinforced carbon fiber to obtain an ultra-thin carbon fiber prepreg.

[0017] The uniform spreading of the fibers is achieved through the combined vibration of the vertical vibration yarn spreading rod and the horizontal vibration yarn spreading rod of the high-precision yarn spreading device, wherein the vibration frequency and amplitude of the vertical vibration yarn spreading rod and the horizontal vibration yarn spreading rod are adjustable.

[0018] The temperature of the high-precision yarn unwinding device is controlled between room temperature and 120°C to adapt to the different properties of resin and carbon fiber materials.

[0019] The temperature of the heated roller is controlled between 97°C and 100°C to facilitate the flow and impregnation of the resin.

[0020] The high-precision yarn spreading device comprises at least one group of vertically vibrating yarn spreading rods and at least two groups of horizontally vibrating yarn spreading rods, which are used to evenly spread the unidirectional reinforced carbon fibers to 5-20 times of their original width.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] Fiber-reinforced thermosetting epoxy resin prepreg is used as the main material for aerospace and 3C electronic products. A high-precision yarn spreading device is used to expand the fiber bundle to 5-20 times the original width. The fiber spreading method is gentle, the fiber damage is small, and the fiber spreading uniformity is good. The fiber surface density is high in precision, so that the matrix resin is evenly and completely immersed in the carbon fiber of the reinforcing material. The obtained ultra-thin prepreg has high precision, good appearance, and a fiber surface density of less than 20g. The single-layer cured thickness of ultra-thin carbon fiber prepreg is thin, which can be used to design and manufacture composite products with more complex structures or extremely thin thickness, effectively improving the product precision, performance stability and product design of carbon fiber composite parts in the fields of aerospace and 3C electronic products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a rheological curve diagram of the ultra-thin carbon fiber prepreg and the matrix resin in the production process thereof of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] The implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0026] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0027] The ultra-thin carbon fiber prepreg is composed of unidirectional reinforced carbon fiber and matrix resin. The unidirectional reinforced carbon fiber is unfolded by a high-precision yarn spreading device so that the fiber surface density is less than or equal to 20g, the fiber distribution is uniform, and the fiber surface density fluctuation is less than or equal to 1g.

[0028] The matrix resin is a thermosetting epoxy resin composition, and the gel time of the epoxy resin composition at 120° C. is less than or equal to 25 minutes.

[0029] The unidirectional reinforced carbon fiber is one or more of T300, T700, T800, T1000, 40J, 55J, and 65J.

[0030] The width of the prepreg is less than or equal to 1005 mm.

[0031] The unidirectional reinforced carbon fiber consists of parallel and symmetrically arranged 0° direction fibers.

[0032] The production process of ultra-thin carbon fiber prepreg is characterized by comprising the following steps:

[0033] e. Use a release paper with high peeling force as the carrier;

[0034] f. coating the base resin on the release paper to form a resin film of a certain quality;

[0035] g. Paste the resin film on the release paper onto the upper and lower surfaces of the evenly spread unidirectional reinforced carbon fiber;

[0036] h. Pressurizing at room temperature to 120°C to completely impregnate the resin with the sheet-like reinforced carbon fiber to produce an ultra-thin carbon fiber prepreg.

[0037] The uniform spreading of the fibers is achieved through the combined vibration of the vertical vibration yarn spreading rod and the horizontal vibration yarn spreading rod of the high-precision yarn spreading device, wherein the vibration frequency and amplitude of the vertical vibration yarn spreading rod and the horizontal vibration yarn spreading rod are adjustable.

[0038] The temperature of the high-precision yarn unwinding device is controlled between room temperature and 120°C to adapt to the different properties of resin and carbon fiber materials.

[0039] The temperature of the heated roller is controlled between 97°C and 100°C to facilitate the flow and impregnation of the resin.

[0040] The high-precision yarn spreading device comprises at least one group of vertically vibrating yarn spreading rods and at least two groups of horizontally vibrating yarn spreading rods, which are used to evenly spread the unidirectional reinforced carbon fibers to 5-20 times of their original width.

[0041] Embodiment 1:

[0042] Ultra-thin carbon fiber prepreg and its production process are used in combination with a high-precision yarn spreading device to produce prepreg with a fiber surface density of 20g. High-strength T700-grade carbon fiber is used as the reinforcement and medium-temperature cured epoxy resin is used as the matrix. The temperature of the yarn spreading device rises to 70°C, and a set of vertical vibration yarn spreading rods and four sets of horizontal vibration yarn spreading rods are activated, wherein the vertical vibration yarn spreading rod has a frequency of 15HZ and an amplitude of 11mm, and the horizontal vibration yarn spreading rods are set to 2 sets of frequencies of 10HZ and 12mm, and 2 sets of frequencies of 13HZ and 13mm, respectively. The pressing height of the yarn spreading rod varies from 30 to 110mm, the width is set to 1000mm, and the temperature of the heating roller is 97°C. In this embodiment, the fiber is fully spread to 8 times the original through the combined vibration of the 3# horizontal vibration yarn spreading rod and the 2# vertical vibration yarn spreading rod. On the premise of ensuring the apparent quality, the fiber surface density of the prepreg is reduced from the original 54g / ㎡ to 20g / ㎡, which greatly improves the production range of the prepreg.

[0043] Embodiment 2:

[0044] Ultra-thin carbon fiber prepreg and its production process are used in combination with a high-precision yarn spreading device to produce prepreg with a fiber surface density of 15g. High-strength T700-grade carbon fiber is used as the reinforcement and medium-temperature curing epoxy resin is used as the matrix. The temperature of the yarn spreading device rises to 98°C, and two sets of vertical vibration yarn spreading rods and four sets of horizontal vibration yarn spreading rods are activated. The vertical vibration yarn spreading rods are set to 1 set of 15HZ frequency, 5mm amplitude and 1 set of 12HZ frequency, 8mm amplitude, and the horizontal vibration yarn spreading rods are set to 2 sets of 4HZ frequency, 12mm amplitude and 2 sets of 3HZ frequency, 16mm amplitude. The pressing height of the yarn spreading rod varies from -27 to 83mm, the width is set to 1000mm, and the temperature of the heating roller is 100°C. This embodiment further disperses the fibers through combined vibration of two sets of 3# horizontal vibration yarn spreading rods and 2# vertical vibration yarn spreading rods on the basis of the 20g prepreg production process, so that the fibers are fully expanded to 11 times the original, so that the fiber surface density can be reduced to 15g / ㎡.

[0045] Embodiment 3:

[0046] Ultra-thin carbon fiber prepreg and its production process are used in combination with a high-precision yarn spreading device to produce prepreg with a fiber surface density of 30g. High modulus M40 grade carbon fiber is used as the reinforcement and medium-temperature curing epoxy resin is used as the matrix. The temperature of the yarn spreading device rises to 90°C, and two sets of vertical vibration yarn spreading rods and four sets of horizontal vibration yarn spreading rods are activated. The vertical vibration yarn spreading rods are set to 1 set of 15HZ frequency, 5mm amplitude and 1 set of 15HZ frequency, 6mm amplitude, and the horizontal vibration yarn spreading rods are set to 2 sets of 3HZ frequency, 15mm amplitude and 2 sets of 2HZ frequency, 14mm amplitude. The pressing height of the yarn spreading rod varies from -35 to 95mm, the width is set to 1000mm, and the temperature of the heating roller is 99°C. This embodiment uses a combined vibration of two groups of 3# horizontal vibration yarn spreading rods and 2# vertical vibration yarn spreading rods to successfully solve the problems of high modulus fibers being brittle and easy to break due to their own high modulus characteristics, and the traditional prepreg production method causing a high yarn breakage rate of high modulus fibers, uneven fiber dispersion, and a large number of hair balls on the prepreg surface. The production process of 30g high modulus prepreg is successfully improved.

[0047] As shown in the drawings, a preferred embodiment of the present invention is provided.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Ultra-thin carbon fiber prepreg, characterized in that: The unidirectional reinforced carbon fiber is composed of unidirectional reinforced carbon fiber and matrix resin. The unidirectional reinforced carbon fiber is unfolded by a high-precision yarn unfolding device so that the fiber surface density is less than or equal to 20g, the fiber is evenly distributed, and the fiber surface density fluctuation is less than or equal to 1g.

2. The ultra-thin carbon fiber prepreg according to claim 1, characterized in that: The matrix resin is a thermosetting epoxy resin composition, and the gel time of the epoxy resin composition at 120° C. is less than or equal to 25 minutes.

3. The ultra-thin carbon fiber prepreg according to claim 2, characterized in that: The unidirectional reinforced carbon fiber is one or more of T300, T700, T800, T1000, 40J, 55J, and 65J.

4. The ultra-thin carbon fiber prepreg according to claim 3, characterized in that: The width of the prepreg is less than or equal to 1005 mm.

5. The ultra-thin carbon fiber prepreg according to claim 4, characterized in that: The unidirectional reinforced carbon fiber consists of parallel and symmetrically arranged 0° direction fibers.

6. The production process of ultra-thin carbon fiber prepreg is characterized in that: The following steps are involved: a. Use a release paper with high peeling force as the carrier; b. coating the base resin on the release paper to form a resin film of a certain quality; c. Paste the resin film on the release paper onto the upper and lower surfaces of the evenly spread unidirectional reinforced carbon fiber; d. Pressurizing at room temperature to 120°C to completely impregnate the resin with the sheet-like reinforced carbon fiber to obtain an ultra-thin carbon fiber prepreg.

7. The production process of ultra-thin carbon fiber prepreg according to claim 6, characterized in that: The uniform spreading of the fibers is achieved through the combined vibration of the vertical vibration yarn spreading rod and the horizontal vibration yarn spreading rod of the high-precision yarn spreading device, wherein the vibration frequency and amplitude of the vertical vibration yarn spreading rod and the horizontal vibration yarn spreading rod are adjustable.

8. The production process of ultra-thin carbon fiber prepreg according to claim 7, characterized in that: The temperature of the high-precision yarn unwinding device is controlled between room temperature and 120°C to adapt to the different properties of resin and carbon fiber materials.

9. The production process of ultra-thin carbon fiber prepreg according to claim 8, characterized in that: The temperature of the heated roller is controlled between 97°C and 100°C to facilitate the flow and impregnation of the resin.

10. The production process of ultra-thin carbon fiber prepreg according to claim 7, characterized in that: The high-precision yarn spreading device comprises at least one group of vertically vibrating yarn spreading rods and at least two groups of horizontally vibrating yarn spreading rods, which are used to evenly spread the unidirectional reinforced carbon fibers to 5-20 times of their original width.

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