KR100783012B1 - Method for manufacturing high performance needle punch fiber preform - Google Patents

Abstract

A method for manufacturing a needle punch type fiber-reinforced material is provided to produce a fiber-reinforced material having a high fiber volume fraction, thereby enhancing the strength of the fiber-reinforced material, by laminating fiber aggregates through spray of liquid so as to decrease the possibility that the compressed fiber aggregates are restored to an original state. Laminated fiber aggregate unit layers(110) are prepared through spray of liquid, wherein the liquid is water or alcohol. The laminated fiber aggregate unit layers are inputted and compressed between supply rollers(101) of a needle punch apparatus. When an interlayer adhesive force is applied to the compressed fiber aggregate unit layers during a needle punch process, the depths of needles(104) are uniformly controlled.

Description

Needle Punch Fiber Reinforcement Manufacturing Method {METHOD FOR MANUFACTURING HIGH PERFORMANCE NEEDLE PUNCH FIBER PREFORM}

1 is a cross-sectional view showing a thickness direction of an example of a fiber reinforcement manufactured by a conventional needle punch fiber reinforcement manufacturing method.

Figure 2 is a view for explaining a fiber assembly laminated structure according to the conventional needle punch fiber reinforcement manufacturing method.

Figure 3 is a schematic perspective view showing an example of a needle punch apparatus for performing a needle punch fiber reinforcement manufacturing method according to the present invention.

It is sectional drawing which shows the example of the needle which comprises a needle punch apparatus.

5 is a cross-sectional view showing a thickness direction of an example of a fiber reinforcement manufactured by the needle punch fiber reinforcement manufacturing method according to the present invention.

Figure 6 is a view for explaining a fiber aggregate laminated structure by a needle punch fiber reinforcement manufacturing method according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100: needle punching device, 101: feed roller,

104: needle, 110: fiber assembly,

120: depth of the needle.

The present invention relates to a method of manufacturing a needle punch fiber reinforcement, and in particular, when the fiber reinforcement used in the manufacture of a composite material is produced by applying the interlayer bonding force to the fiber assembly in the needle punch (Needle Punch) method, a liquid By spraying the lamination of fiber assemblies, the insertion depth of the needle is always controlled constantly, and when adding a new fiber assembly by simply laminating in one direction of the layer and changing the input direction, it is possible to increase the performance of the fiber reinforcement A high performance needle punch fiber reinforcement is provided.

The needle punch fiber reinforcement manufacturing method, which is a method of manufacturing a fiber reinforcement, installs needles having small protrusions on a needle plate and repeatedly penetrates the needles in the thickness direction of the laminated fiber assembly, thereby removing a part of the fibers. By inserting in the thickness direction, it is a method of providing an interlayer bonding force to a fiber assembly. In this way, a significantly thicker fiber reinforcement is produced by further laminating a new layer on the fiber assembly and again subjecting the needle punch.

Looking at the conventional needle punch fiber reinforcement manufacturing method, there is an advantage that can be manufactured in a fast and low cost fiber reinforcement, as shown in Figure 1, the needle depth 120 between the fiber assembly 110 is one Since the interlayer bonding force of the fiber assemblies 110 is not uniform due to standing, the phenomenon in which the fiber assemblies 110 compressed by the feed roller 101 of the needle punch device 100 is restored to its original state during the manufacturing process It appears that the fiber volume fraction in the prepared fiber reinforcement is not high. In addition, when the new fiber assembly 110 is laminated on the fiber assembly 110 in which the previous needle punching process is completed, as shown in FIG. 2, for example, two to five fiber assemblies are arranged in both directions of the fiber assembly 1. Since they are stacked alternately, the needle depth 120 cannot be constantly controlled, so that the interlayer bonding force is all different.

Therefore, in the conventional needle punch fiber reinforcement manufacturing method, as a result, the strength of the fiber reinforcement is lowered, and in particular, there is a problem that the interlayer bonding strength is not sufficient, so that it is vulnerable to deformation or breakage such as bending or interlayer separation.

This disadvantage can be somewhat compensated by increasing the number of needle punches, there is a problem that the damage to the fiber reinforcement of the fiber reinforcement is increased by increasing the fiber damage by the needle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, by spraying liquid to stack fiber assemblies, constantly controlling the insertion depth of the needle, and simply stacking in one direction of the layer when adding a new fiber assembly. An object of the present invention is to provide a high-performance needle punch fiber reinforcement manufacturing method capable of increasing the performance of fiber reinforcement by changing the feeding direction.

In order to achieve the above object, the needle punch fiber reinforcement manufacturing method according to the present invention comprises the steps of preparing a laminated fiber aggregate unit layer by spraying a liquid; Inserting the fiber aggregate unit layer between feed rollers of a needle punch device and compressing the fiber aggregate unit layer; And, when applying the interlayer adhesion to the crimped fiber aggregate unit layer by the needle punch process, the step of controlling the depth of the needle; is made.

According to the present invention, it is preferable to vary the stacking direction of the new fiber assembly unit layers whenever the new fiber assembly unit layer is additionally laminated to the fiber assembly unit layer on which the previous needle punching process is completed.

In addition, whenever a new fiber assembly unit layer is additionally laminated to the fiber assembly unit layer on which the previous needle punching process is completed, it is preferable to simply laminate in one direction of both sides.

In addition, whenever a new fiber aggregate unit layer is stacked on the fiber aggregate unit layer where the preceding needle punching process is completed and introduced into the feed rollers, it is preferable to change the process feeding direction in various ways.

In addition, the liquid is preferably a liquid capable of maintaining a high fiber volume fraction by preventing the fiber aggregates compressed by water, alcohol or rollers from being restored to their original state.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are defined in the technical spirit of the present invention on the basis of the principle that the inventor can appropriately define the concept of the term in order to explain his invention in the best way. It must be interpreted to mean meanings and concepts.

3 shows an example of a needle punch apparatus for performing a needle punch fiber reinforcement manufacturing method according to the present invention.

The needle punch device 100 shown in FIG. 3 includes a pair of feed rollers 101 and 101 which are pressed while passing the fiber aggregates 110 to be introduced; Needles 104 which penetrate the conveyed fiber assemblies 110 repeatedly in the thickness direction to insert a part of the fibers in the thickness direction to impart interlayer bonding force to the fiber assemblies 110; A needle plate 103 for supporting the needles 104; And a pair of discharge rollers 102 and 102 for discharging the fiber reinforcement having the interlayer bonding force by the needle punch process.

As the material of the fiber assembly 110, an organic fiber or an inorganic fiber may be applied, and a woven fabric, a non-woven fabric, a knitted fabric, and one direction Fiber assemblies may be provided in the form of a unidirectional fabric, a multiaxial wrap knitted fabric, or the like.

The fiber assembly 110 is stacked in multiple layers and introduced into the needle punch equipment, and the feed rate and discharge rate are controlled by the supply rollers 101 and the discharge rollers 102.

On the side of the needles 104 supported by the needle plate 103, as shown in Figure 4, there are a plurality of small projections 105, the needles 104 are moved downward to feed the feed rollers 101 When passing through the compressed fiber assembly 110 while passing through, the fibers in the upper fiber assembly 110 is caught by the protrusions 105 is pulled down in the thickness direction of the lower fiber assembly 110, dragged down Since the fibers are raised only by the needles 104 while remaining in the lower fiber assembly 110 during the upward movement of the needles 104, the layers between the fiber assemblies 110 are combined.

The fiber aggregates 110 are compressed by the compressive force of the feed rollers 101 to reduce the thickness, and at the same time, the fiber volume fraction also increases, but after the needle punching process is finished, the thickness is increased again by the restoring force of the fiber aggregates 110. In order to prevent the phenomenon, in the present invention, an appropriate liquid that can prevent the restoration of the fiber aggregates 110 is sprayed for each layer of the fiber aggregate 110 in order to prevent the phenomenon. Use a method to prevent fractional drops.

As the liquid, water, alcohol or other liquid may be selected, among the liquids capable of maintaining a high fiber volume fraction by preventing the fiber aggregates 110 compressed by the rollers from being restored to their original state again. It may be selected in consideration of the type and viscosity of the liquid.

In order to manufacture a thick fiber reinforcement, since only one needle punch process is insufficient (that is, only two fiber assemblies 110), on the fiber assembly 110 subjected to the needle punch process, as described above, new The process of laminating the layers and performing the needle punching process again is repeated until the desired thickness is obtained. In this process, when stacking a new fiber assembly 110 layer, and then again put into the needle punch device 100, by changing the process input direction differently from the direction initially introduced, the direction that is vulnerable to the fiber reinforcement does not occur It is preferable to make the physical properties of the fiber reinforcement appear uniformly quasi-isotropic.

For example, the process input direction of the fiber assembly 110 is alternately used in two directions at 0 ° and 90 °, or alternatively using three directions of 0 °, 60 ° and 120 °, or 0 °, 45 °, 90 °. Four directions of ° and 135 ° can be used alternately.

This direction control may be applied in the same manner as described above to change the stacking direction of the new fiber assembly 110 every time the new fiber assembly 110 is stacked on the fiber assembly 110, the previous needle punch process is completed. .

After the new fiber assembly 110 is stacked on the fiber assembly 110 where the previous needle punching process is completed, the needles 103 are always adjusted to the same depth 120 by adjusting the height of the needle plate 103 together. 110) it is desirable to be inserted into the interior. That is, when the position of the needle plate 103 is moved upward by the thickness of the newly added fiber assembly 110, the distance between the surface of the newly laminated fiber assembly 110 and the needle 104 is kept constant. As shown in FIG. 5, the needle (with a uniform depth 120 per layer from the fiber assembly 110 of the bottom layer where the needle punching process was first performed to the fiber assembly 110 where the needle punching process was performed last). 104 is inserted so that the fibers uniformly bind the layers of the fiber assemblies 110, so that no deviations between the layers occur.

As such, when a needle punch having a uniform density is generated for each layer to have a uniform interlayer bonding structure, the fiber reinforcement has a uniform physical property in the thickness direction, and thus deformation or breakage such as warpage or separation of the fiber reinforcement. This will not happen.

Thus, as shown in Figure 1, by performing the needle punch process without controlling the position of the needle plate as in the prior art, the insertion of the needle is made to a non-uniform depth for each layer, the interlayer bonding force is all different, the fiber reinforcement It is possible to prevent the occurrence of deformation or breakage, such as warpage or delamination.

The additional stacking direction of the new fiber assembly 110 with respect to the fiber assembly 110 in which the preceding needle punching process is completed, as shown in FIG. 6, on either side of the both sides of the fiber assembly 110 in which the preceding needle punching process is completed. It is preferable to perform the needle punch process repeatedly by simply laminating only. In other words, for one of the two sides of the first fiber assembly 110, for example, the second to fifth simple fiber assemblies 110 are simply stacked in sequence, and the needle punching process is repeated.

In this case, as shown in Figure 2, by performing a needle punch process by laminating new fiber aggregates in both the up and down direction of the fiber assembly No. 1 conventionally, it is vulnerable to receiving excessive needle punch in both directions to generate a large amount of fiber damage The problem of remaining layers can be solved.

Next, the physical properties of the fiber reinforcement prepared according to the embodiment of the present invention and the fiber reinforcement prepared according to the comparative examples of the method different from the present invention was compared.

<Example 1>

Stabilized Oxi-PAN Fiber was woven into a one-way array fabric with a thickness of about 0.4 mm and a weight of 200 g / m 2. In preparing 10 layers of woven one-way array fabrics and preparing a fiber aggregate unit layer having a thickness of about 4 mm, after laminating 10% aqueous polyvinyl alcohol solution onto the surface of the one-way array fabric, 10 sheets of fabric were stacked alternately in directions of 0 ° and 90 ° to prepare a fiber assembly unit layer.

Next, the prepared fiber aggregate unit layer was introduced into the needle punch apparatus 100 to perform a needle punch process. At this time, the insertion depth 120 of the needle 104 was adjusted to be 25 mm from the top of the fiber assembly 110.

In addition, after laminating a new fiber assembly unit layer on the fiber assembly unit layer after the needle punching process, the process is repeated by inserting into the needle punch device 100 to perform the needle punching process, and the fiber reinforcement having a total thickness of 20 mm. After completion of the above, high temperature heat treatment at 1000 ° C. or higher was carried out in a nitrogen atmosphere to obtain a carbon fiber reinforcement product.

At this time, each time the new fiber aggregate unit layer is stacked and introduced, the fiber aggregate unit layer is newly added to the needle punching device 100 by rotating by 90 ° in the direction of the preceding process, and the position of the needle 104 is newly added. By adjusting the thickness of 4mm upward, the insertion depth 120 of the needle 104 was always 25mm from the top of the fiber assembly 110, and the addition of the fiber assembly unit layer was such that the addition of the fiber assembly unit layer was simply laminated in one direction only. .

Comparative Example 1

Carbon fiber reinforcement was prepared in the same manner as in Example 1 without spraying an aqueous polyvinyl alcohol solution.

Comparative Example 2

The feed direction to the needle punch device 100 was always added in the same direction without rotating by 90 °, thereby producing carbon fiber reinforcement in the same manner as in Example 1.

Comparative Example 3

The carbon fiber reinforcement was prepared in the same manner as in Example 1 without adjusting the position of the needle 104 for each additional lamination of the new fiber assembly unit layer.

<Comparative Example 4>

At the time of further lamination of the new fiber assembly unit layer, the carbon fiber reinforcement was prepared in the same manner as in Example 1 by alternately laminating in both directions, instead of simply laminating in only one direction.

Table 1 below shows the results of testing the physical properties of the fiber reinforcement according to Example 1 and the fiber reinforcement according to the comparative examples described above.

Fiber volume fraction (%) Weak direction Deformation and damage after heat treatment Example 1 32 none none Comparative Example 1 22 none none Comparative Example 2 31 The direction of inserting needle punch is weak none Comparative Example 3 32 none warp Comparative Example 4 30 none Delamination occurs

As shown in Table 1, in the case of the carbon fiber reinforcement according to Example 1 to which the method of the present invention is applied, the fiber volume fraction is excellent, there is no fragile direction, and has excellent physical properties without deformation or damage even after heat treatment. I could see that.

In addition, in the case of the carbon fiber reinforcement according to Comparative Example 1, it was found that the liquid volume was omitted so that the compressed state was returned to the substantial part again after the needle punch, resulting in a very low fiber volume fraction.

In addition, in the case of the carbon fiber reinforcement according to Comparative Example 2, it was found that the needle punch process feeding direction was always performed in the same direction, so that it was fragile and easily torn in the direction perpendicular to the needle punching process feeding direction. .

In addition, in the case of the carbon fiber reinforcement according to Comparative Example 3, the position of the needle 104 is not always adjusted to have a uniform insertion depth 120, so that each time the new fiber assembly unit layer is added, the needle 104 and the fiber As the distance between the assemblies 110 approaches, as a result, the insertion depth 120 of the needle 104 also gradually increases. Due to such a change in the internal structure, it was found that the difference in the internal stress occurs during the high temperature heat treatment process to show the result of the fiber reinforcement bend.

In addition, in the case of the carbon fiber reinforcement according to Comparative Example 4, the addition of a new fiber aggregate unit layer is performed on both sides of the upper and lower, so that a large amount of needle punch occurs in the first unit layer located at the center, and significant fiber damage occurs. It was found that the interlaminar separation phenomenon could not be overcome by the internal stress generated during the high temperature heat treatment process.

The above embodiment is only one example, and may be manufactured in various standards and methods according to the manufacturing method of the present invention, all of which should also be included in the scope of the present invention.

According to the method of manufacturing a needle punch fiber reinforcement according to the present invention configured as described above, by spraying a liquid to laminate the fiber assembly 110, the phenomenon in which the compressed fiber assembly 110 is restored to its original state is reduced to a high A high strength fiber reinforcement having a fiber volume fraction can be obtained.

In addition, by constantly controlling the insertion depth 120 of the needle 104 and simply adding in one direction of the layer when the new fiber assembly 110 is added and changing the feeding direction, the direction vulnerable to the fiber reinforcement is Because the physical properties of the fiber reinforcements are quasi-isotropic evenly, and there is no variation between the layers, the fiber reinforcements have uniform properties in the thickness direction. A high performance fiber reinforcement that does not occur can be obtained.

Claims (5)

Spraying a liquid to prepare a laminated fiber aggregate unit layer; Inserting the fiber aggregate unit layer between feed rollers of a needle punch device and compressing the fiber aggregate unit layer; And, When imparting the interlayer adhesion to the crimped fiber aggregate unit layer by a needle punch process, controlling the depth of the needle to a constant; needle punch fiber reinforcement manufacturing method comprising a. The method of claim 1, A method of manufacturing a needle punch fiber reinforcement, characterized in that the direction of stacking the fiber aggregate unit layers is variously changed whenever a new fiber aggregate unit layer is additionally laminated to the fiber aggregate unit layer on which the previous needle punching process is completed. delete The method of claim 1, Needle punch fiber reinforcement, characterized in that the process injection direction is changed in various ways when the new fiber aggregate unit layer is stacked between the feed rollers of the needle punch device by stacking a new fiber aggregate unit layer on the fiber aggregate unit layer on which the preceding needle punching process is completed. Manufacturing method. The method of claim 1, The liquid is, Needle punch fiber reinforcement manufacturing method, characterized in that the water or alcohol.

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