阅读说明：本技术 一种超薄连续纤维增强热塑性预浸料的制备方法 (Preparation method of ultrathin continuous fiber reinforced thermoplastic prepreg ) 是由 郭玉琴 陆铭 段梦思 陈龙 李富柱 徐凡 吴雪莲 许桢英 于 2020-06-28 设计创作，主要内容包括：本发明提供了一种超薄连续纤维增强热塑性预浸料的制备方法,包括带微锥孔阵列特征金属模具加工、带微锥形突起阵列特征的开纤板翻制、超薄纤维布初次开纤、基体树脂粉末振动撒粉、二次开纤、初次翻转匀粉、二次翻转换模、真空加热熔融和热压成型。在金属模具表面加工出阵列锥形孔,利用高性能热塑性PEEK树脂薄板,翻制出带微锥形突起阵列特征的开纤板,实现对超薄连续增强纤维布的充分开纤,开纤效果好；配合流量可控的三坐标可移动漏嘴和开纤板的两次高频低幅振动撒粉,实现基体树脂粉末在增强纤维布内部的均匀分布,有效解决了熔融态树脂基体深入连续纤维束内部难的问题。(The invention provides a preparation method of an ultrathin continuous fiber reinforced thermoplastic prepreg, which comprises the steps of processing a metal die with a micro-cone array characteristic, copying a fiber opening plate with a micro-cone protrusion array characteristic, primarily opening ultrathin fiber cloth, vibrating and dusting matrix resin powder, secondarily opening fiber, primarily turning and homogenizing the powder, secondarily turning and replacing a die, carrying out vacuum heating melting and hot-pressing forming. Processing an array tapered hole on the surface of a metal mould, and copying a fiber opening plate with micro-conical protrusion array characteristics by using a high-performance thermoplastic PEEK resin thin plate to realize full fiber opening of the ultrathin continuous reinforced fiber cloth, wherein the fiber opening effect is good; the flow-controllable three-coordinate movable discharge spout is matched with twice high-frequency low-amplitude vibration dusting of the fiber opening plate, so that the uniform distribution of matrix resin powder in the reinforced fiber cloth is realized, and the problem that a molten state resin matrix is difficult to penetrate into a continuous fiber bundle is effectively solved.)

1. The preparation method of the ultrathin continuous fiber reinforced thermoplastic prepreg is characterized by comprising the following steps of: processing a metal die with micro-cone hole array characteristics, copying a fiber opening plate with micro-cone protrusion array characteristics, opening ultra-thin fiber cloth for the first time, vibrating and dusting matrix resin powder, opening fiber for the second time, turning and homogenizing the powder for the first time, turning and changing a die for the second time, heating and melting in vacuum, and hot-pressing for molding.

2. The method for preparing the ultrathin continuous fiber reinforced thermoplastic prepreg of claim 1, wherein the metal mold with the micro-taper hole array characteristic is perforated by laser, and array taper holes are processed on the surface of the metal mold.

3. The method of claim 2, wherein the diameter, the number of rows and the number of columns of the array of tapered holes are determined by the degree of opening, and the depth of the array of tapered holes is determined by the thickness of the prepared prepreg.

4. The method for preparing the ultrathin continuous fiber reinforced thermoplastic prepreg according to claim 1, wherein the copying of the micro-cone protrusion array characteristic fiber opening plate comprises the following specific steps: after the high-performance thermoplastic PEEK resin sheet is flatly placed on the metal mold, the high-performance thermoplastic PEEK resin sheet is heated to the melting temperature of a PEEK material, the PEEK resin in a molten state flows into the array micro-conical holes of the metal mold through pressurization, after the PEEK resin is cooled and solidified, the PEEK resin is peeled off from the surface of the metal mold, and an upper fiber opening plate and a lower fiber opening plate with micro-conical protrusion array characteristics are manufactured.

5. The method for preparing the ultrathin continuous fiber reinforced thermoplastic prepreg according to claim 4, wherein the ultrathin fiber cloth is subjected to primary fiber opening, and the specific process is as follows: and (3) under the tensioning state, the ultrathin fiber cloth is pulled into one surface of the lower fiber plate with the micro-cone-shaped protrusion array, so that the micro-cone-shaped protrusion array forms dense pinning in the fiber cloth.

6. The method for preparing the ultrathin continuous fiber reinforced thermoplastic prepreg according to claim 5, wherein the vibration dusting of the matrix resin powder is specifically as follows: and uniformly scattering matrix resin powder of the prepreg to the reinforced fiber cloth subjected to primary fiber splitting, and simultaneously driving the lower fiber-opening plate to perform high-frequency low-amplitude vibration through a vibration motor.

7. The method of claim 6, wherein the secondary opening is performed by placing an upper opening plate on the powdered primary opening fiber cloth, and pressing the upper and lower opening plates while keeping the protrusions on the surfaces of the upper and lower opening plates staggered.

8. The method for preparing the ultrathin continuous fiber reinforced thermoplastic prepreg according to claim 7, wherein the primary tumbling refining is specifically: turning the upper and lower fiber plates and the fiber cloth clamped between the upper and lower fiber plates for 180 degrees, removing the lower fiber plate, uniformly scattering matrix resin powder of the prepreg to the surface of the reinforced fiber cloth, and simultaneously keeping the upper fiber plate to perform high-frequency low-amplitude vibration.

9. The method for preparing the ultrathin continuous fiber reinforced thermoplastic prepreg according to claim 8, wherein the secondary turnover die change is completed by placing a smooth metal flat upper die on the fiber cloth after powder distribution, turning the fiber cloth in the reverse direction by 180 degrees, removing the upper fiber opening plate, and placing a smooth metal flat lower die on the other side of the fiber cloth.

10. The method for preparing the ultrathin continuous fiber reinforced thermoplastic prepreg of claim 9, wherein a gap adjusting sheet is placed between the upper metal flat mold and the lower metal flat mold during vacuum heating melting and hot press molding.

Technical Field

The invention relates to the field of fiber reinforced composite material preparation, in particular to a preparation method of an ultrathin continuous fiber reinforced thermoplastic resin matrix prepreg.

Background

In recent years, continuous fiber reinforced thermoplastic resin matrix prepregs have attracted much attention in the fields of automobiles, ships, rail transportation, and the like because of their characteristics such as high specific strength, high specific stiffness, and low density. For continuous fiber reinforced thermoplastic prepregs, especially ultra-thin prepregs, the distribution uniformity of continuous fibers in a resin matrix and the impregnation effect of the resin matrix on the continuous fibers directly affect the mechanical property stability and service safety of the prepared composite material member.

On the one hand, in the whole preparation process of the continuous fiber reinforced thermoplastic prepreg, the process link directly related to the distribution uniformity of the fibers is fiber bundle opening. The fiber opening methods commonly used at present mainly include: an air-jet fiber-opening method, a roller fiber-opening method, and an air-jet roller hybrid fiber-opening method. The method has the advantages that the gas acting force is small, the monofilament fiber is less in breakage, but the sizing agent is used for the conventional reinforcing fiber based on the purposes of bundling and interface improvement, so that the fiber bundle is difficult to separate, and the fiber opening effect is not ideal. The roller opening method is a mechanical opening method, and can reduce the influence of sizing agent, but the opening effect is influenced by various factors such as traction tension, roller diameter, contact angle between fiber bundle and roller, and the like, and the opening effect is unstable. Therefore, a more efficient and stable continuous fiber opening mode is sought, and the method has a vital significance for ensuring the quality of the ultrathin continuous fiber thermoplastic prepreg.

On the other hand, due to the characteristics of high melting temperature, high viscosity, poor fluidity and the like of the thermoplastic resin matrix, in the conventional continuous fiber prepreg prepared by the melt infiltration method, the resin matrix is difficult to infiltrate among fiber filaments in a fiber bundle to form ideal infiltration, so that the performance of the continuous fiber reinforced thermoplastic prepreg is influenced. In order to solve the problem, Chinese patent (CN105885072) provides a preparation method of a unidirectional continuous fiber reinforced resin matrix composite prepreg, wherein suspension containing resin matrix powder and a soluble binder is prepared by a phase inversion method and used for impregnating fiber bundles, the fiber bundles are distributed after being impregnated, and a solvent is dried by distillation and then wound to prepare the prepreg. Although the method avoids the problems of high viscosity, poor fluidity and the like of molten resin to a great extent, the requirement on suspension liquid configuration is high, and the interface bonding strength between fibers and resin matrixes in the prepared prepreg is low because the resin matrix powder is not molten.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of an ultrathin continuous fiber reinforced thermoplastic prepreg, which effectively solves the problem that a molten resin matrix is difficult to penetrate into a continuous fiber bundle.

The present invention achieves the above-described object by the following technical means.

A preparation method of an ultrathin continuous fiber reinforced thermoplastic prepreg comprises the following steps: processing a metal die with micro-cone hole array characteristics, copying a fiber opening plate with micro-cone protrusion array characteristics, opening ultra-thin fiber cloth for the first time, vibrating and dusting matrix resin powder, opening fiber for the second time, turning and homogenizing the powder for the first time, turning and changing a die for the second time, heating and melting in vacuum, and hot-pressing for molding.

Further, the metal die with the micro-taper hole array characteristic is drilled by laser, and array taper holes are machined on the surface of the metal die.

Furthermore, the diameter, the number of rows and the number of columns of the array tapered holes are determined by the fiber opening degree, and the depth of the array tapered holes is determined by the thickness of the prepared prepreg.

Further, the copying of the micro-conical protrusion array characteristic fiber opening plate specifically comprises the following steps: after the high-performance thermoplastic PEEK resin sheet is flatly placed on the metal mold, the high-performance thermoplastic PEEK resin sheet is heated to the melting temperature of a PEEK material, the PEEK resin in a molten state flows into the array micro-conical holes of the metal mold through pressurization, after the PEEK resin is cooled and solidified, the PEEK resin is peeled off from the surface of the metal mold, and an upper fiber opening plate and a lower fiber opening plate with micro-conical protrusion array characteristics are manufactured.

Furthermore, the initial opening of the ultrathin fiber cloth comprises the following specific processes: and (3) under the tensioning state, the ultrathin fiber cloth is pulled into one surface of the lower fiber plate with the micro-cone-shaped protrusion array, so that the micro-cone-shaped protrusion array forms dense pinning in the fiber cloth.

Furthermore, the base resin powder is subjected to vibration dusting, and specifically comprises the following components: and uniformly scattering matrix resin powder of the prepreg to the reinforced fiber cloth subjected to primary fiber splitting, and simultaneously driving the lower fiber-opening plate to perform high-frequency low-amplitude vibration through a vibration motor.

Furthermore, the secondary opening is to place an upper opening fiber plate above the powdered primary opening fiber cloth, keep the protrusions on the surfaces of the upper and lower opening fiber plates staggered and pressed downwards, and perform secondary opening.

Further, the primary turning and homogenizing specifically comprises: turning the upper and lower fiber plates and the fiber cloth clamped between the upper and lower fiber plates for 180 degrees, removing the lower fiber plate, uniformly scattering matrix resin powder of the prepreg to the surface of the reinforced fiber cloth, and simultaneously keeping the upper fiber plate to perform high-frequency low-amplitude vibration.

Furthermore, the secondary turnover die change is to place a smooth metal flat plate upper die on the fiber cloth after powder distribution, turn over in 180 degrees in reverse, remove the upper fiber opening plate, place a smooth metal flat plate lower die on the other side of the fiber cloth, and complete die change.

Furthermore, when the vacuum heating melting and the hot press molding are carried out, a gap adjusting sheet is arranged between the upper metal flat plate die and the lower metal flat plate die.

After the technical scheme is adopted, the invention has the beneficial effects that:

according to the invention, by utilizing a laser drilling mode, array tapered holes are processed on the surface of a metal die, and by utilizing a high-performance thermoplastic PEEK resin sheet, a fiber opening plate with micro-tapered protrusion array characteristics is manufactured, so that the full opening of the ultrathin continuous reinforced fiber cloth is realized, and the fiber opening effect is good; the flow-controllable three-coordinate movable discharge spout is matched with twice high-frequency low-amplitude vibration dusting of the fiber opening plate, so that the uniform distribution of matrix resin powder in the reinforced fiber cloth is realized, and the problem that a molten state resin matrix is difficult to penetrate into a continuous fiber bundle is effectively solved. When the ultrathin prepreg is subjected to hot press molding, the thickness of the prepared ultrathin continuous fiber reinforced thermoplastic prepreg is controlled by arranging the gap adjusting sheet between the upper die and the lower die of the smooth metal flat plate.

Drawings

FIG. 1 is a schematic diagram of a preparation process of the ultrathin continuous fiber reinforced thermoplastic prepreg.

In the figure: 1. the manufacturing method comprises the following steps of (1) manufacturing an aluminum thin plate, 2) a metal mold, 3) a thermoplastic PEEK resin thin plate, 4. a lower fiber opening plate, 5.3K unidirectional carbon fibers, 6. a primary fiber opening fiber bundle, 7. a three-coordinate movable discharge spout, 8. matrix resin powder, 9. a vibration motor, 10. an upper fiber opening plate, 11. a secondary fiber opening fiber bundle, 12. a metal flat plate upper mold, 13. a metal flat plate lower mold and 14. an ultrathin prepreg.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.

As shown in fig. 1, the method for preparing the ultrathin continuous fiber reinforced thermoplastic prepreg specifically comprises the following steps:

step (1), by utilizing a laser drilling mode, controlling the laser frequency to be 20KHz, the laser power to be 16W and the spot diameterAnd (3) processing 30 rows by 30 columns of array tapered holes with the diameter of 0.8mm and the depth of 1mm on the surface of a 1050-H14 aluminum thin plate 1 with the length, the width and the thickness of 100mm by equal parameters of 20 times of impact times, and preparing the metal mold 2 with the micro-tapered hole array characteristic, wherein the diameter, the rows and the columns of the array tapered holes are determined by the fiber opening degree, and the depth of the array tapered holes is determined by the thickness of the prepared prepreg.

And (2) spraying a release agent on one surface of the metal mold 2 with the micro-conical hole array characteristic, horizontally placing a heat-resistant high-performance thermoplastic PEEK resin sheet 3 (with the thickness of 1mm) on the metal mold 2 with the micro-conical hole array characteristic, placing the metal mold 2 in a vacuum heating furnace, heating to the PEEK material melting temperature (343 ℃), pressurizing by using a press machine to enable the molten PEEK resin to flow into the array conical holes on the metal mold 2, stripping the PEEK resin from the metal mold 2 after the PEEK resin is cooled and solidified, repeating the process, and turning an upper fiber opening plate 10 and a lower fiber opening plate 4 with the micro-conical protrusion array characteristic.

And (3) tensioning the ultrathin continuous reinforced fiber cloth, and quickly tightening one surface of the lower fiber opening plate 4 with the micro-conical protrusion arrays to enable the micro-conical protrusion arrays to form an intensive pinning effect in the fiber cloth, so that the initial fiber opening of the continuous fiber bundle is realized, and the initial fiber opening fiber bundle 6 is obtained. The fiber cloth in the embodiment is preferably 3K unidirectional carbon fiber cloth 5 with the thickness of 0.22mm, and can be replaced by other types and bidirectional carbon fiber cloth.

And (4) uniformly scattering matrix resin powder 8 of the prepreg to the primary opening fiber bundle 6 by using a flow-controllable three-coordinate movable discharge spout 7, and driving the lower opening fiber plate 4 to vibrate at high frequency and low amplitude by using a vibration motor 9 to enable the matrix resin powder 8 to sink into the continuous fiber bundle so as to realize 8 vibration powder scattering of the matrix resin powder.

And (5) placing an upper fiber opening plate 10 with a micro-conical protrusion array above the primary fiber opening bundle 6 subjected to vibration dusting, enabling one surface with the micro-conical protrusions to face the primary fiber opening bundle 6, keeping the protrusions on the surfaces of the lower fiber opening plate 4 and the upper fiber opening plate 10 staggered, and then pressing downwards to perform secondary fiber opening to obtain a secondary fiber opening bundle 11.

And (6) turning the upper fiber opening plate 10 and the lower fiber opening plate 4 together with the secondary fiber opening fiber bundle 11 clamped in the middle for 180 degrees, wherein the upper fiber opening plate 10 is positioned below the secondary fiber opening fiber bundle 11, the lower fiber opening plate 4 is positioned above the secondary fiber opening fiber bundle 11, then removing the lower fiber opening plate 4, and uniformly scattering matrix resin powder 8 of the prepreg to the surface of the secondary fiber opening fiber bundle 11 again by using a flow-controllable three-coordinate movable leakage nozzle 7 while keeping the upper fiber opening plate 10 turned to the lower side to perform high-frequency low-amplitude vibration (driven by a vibration motor 9) so as to realize powder uniformity.

And (7) placing a smooth metal flat plate upper die 12 coated with a high-temperature-resistant release agent (JD-3028 boron nitride) on the twice-opened fiber bundle 11 after the powder is homogenized, turning over the twice, locating the metal flat plate upper die 12 below the twice-opened fiber bundle 11, returning the upper opened fiber plate 10 to the position above the twice-opened fiber bundle 11, then removing the upper opened fiber plate 10, placing a smooth metal flat plate lower die 13 coated with the high-temperature-resistant release agent (JD-3028 boron nitride) above the twice-opened fiber bundle 11, and completing die replacement.

And (8) transferring the metal flat upper die 12 and the metal flat lower die 13 together with the secondary split fiber bundles 11 which are clamped between the two dies and are scattered with the matrix resin powder 8 into a vacuum heating furnace, heating to the melting temperature of the prepreg matrix resin, quickly transferring the prepreg matrix resin to a press machine for hot press molding, placing a gap adjusting sheet between the metal flat upper die 12 and the metal flat lower die 13 to adjust the thickness of the prepreg so as to ensure the thickness requirement of the ultrathin prepreg, and cooling and demolding to obtain the unidirectional continuous carbon fiber thermoplastic ultrathin prepreg 14.

The above description is only one embodiment of the present invention in order to facilitate further understanding of the present invention by those skilled in the art, and is not intended to limit the present invention in any way. On the premise of not departing from the concept of the invention, various insubstantial improvements and replacements made on the invention, such as the used fiber opening plate material, resin matrix, the type of the reinforced continuous fiber, the change and expansion of the weaving method and the like, belong to the protection scope of the invention.