KR102284616B1 - Hybrid fiber reinforced composite material for car parts - Google Patents

Abstract

Disclosed is a hybrid fiber-reinforced composite material for automobile parts having excellent flexural strength.
Hybrid fiber-reinforced composite material for automobile parts according to the present invention includes at least one or more long fiber reinforced thermoplastic (LFT) sheets; and at least three or more continuous fiber reinforced thermoplastic (CFT) sheets, wherein the continuous fiber reinforced thermoplastic (CFT) sheet includes continuous fibers having orientation in a single direction. and continuous fiber included in the other continuous fiber reinforced thermoplastic (CFT) sheet adjacent to the orientation direction of the continuous fiber included in one continuous fiber reinforced thermoplastic (CFT) sheet The angle formed by the orientation direction of is characterized in that 175 ~ 185˚.

Description

Hybrid fiber-reinforced composite material for automobile parts

The present invention relates to a hybrid fiber-reinforced composite material, and more particularly, a combination of a long fiber reinforced thermoplastic (LFT) sheet and at least three or more continuous fiber reinforced thermoplastic (CFT) sheets It relates to a hybrid fiber-reinforced composite material for an automobile part.

In the past, automobile parts were manufactured with metal materials to secure high strength and high rigidity. In the case of automobile parts made of metal, manufacturing costs are high during processing, and as the weight increases, it is difficult to secure weight reduction.

Recently, instead of metal, automobile parts are manufactured using plastic materials consisting of reinforcing fibers and a resin matrix to secure weight reduction.

For example, plastics composed of reinforcing fibers and a resin matrix exhibit light weight, high strength and high rigidity by controlling the content and type of fibers. While the composite material including the composite material has excellent formability, it is difficult to exhibit high strength, and the composite material including only continuous fibers has excellent strength and rigidity, but has weak formability compared to the composite material including long fibers.

Therefore, there is a need for research on fiber-reinforced composites that can exhibit light weight, high strength and high rigidity in order to be applied to automobile parts.

As a background art related to the present invention, there is Korean Patent Application Laid-Open No. 10-2013-0138095 (published on December 18, 2013), which describes a composite laminate including a cross-ply having an optimized orientation.

An object of the present invention is to provide a hybrid fiber-reinforced composite material for automobile parts having excellent flexural strength.

Hybrid fiber-reinforced composite material according to the present invention for achieving the above object is at least one or more long fiber reinforced thermoplastic resin (long fiber reinforced thermoplastic, LFT) sheet; and at least three or more continuous fiber reinforced thermoplastic (CFT) sheets, wherein the continuous fiber reinforced thermoplastic (CFT) sheet includes a continuous fiber having orientation in a single direction. and continuous fiber included in the other continuous fiber reinforced thermoplastic (CFT) sheet adjacent to the orientation direction of the continuous fiber included in one continuous fiber reinforced thermoplastic (CFT) sheet The angle formed by the orientation direction of is characterized in that 175 ~ 185˚.

At least three or more continuous fiber reinforced thermoplastic (CFT) sheets may be continuously laminated.

The long fiber reinforced thermoplastic (LFT) sheet may have a thickness of 0.1 to 2 mm.

The continuous fiber reinforced thermoplastic (CFT) sheet may have a thickness of 0.1 to 2 mm.

The long fiber reinforced thermoplastic (LFT) sheet may include 20 to 60 parts by weight of long fibers based on 100 parts by weight of the first thermoplastic resin.

The continuous fiber reinforced thermoplastic (CFT) sheet may include 20 to 60 parts by weight of continuous fibers with respect to 100 parts by weight of the second thermoplastic resin.

The long fiber reinforced thermoplastic (LFT) sheet may include long fibers having a length of 20 to 50 mm.

The hybrid fiber-reinforced composite may have a flexural strength of 200 to 400 MPa according to ASTM D790.

The hybrid fiber-reinforced composite material for automobile parts according to the present invention has excellent physical properties of not only formability but also high strength and high rigidity by laminating a long fiber-reinforced thermoplastic resin (LFT) sheet and a continuous fiber-reinforced thermoplastic resin (CFT) sheet. can indicate

In particular, when three or more continuous fiber-reinforced thermoplastic resin (CFT) sheets are continuously laminated in a fiber-reinforced composite material and disposed on the rear surface at the same time, excellent flexural strength may be exhibited.

1 is a perspective view of a hybrid fiber-reinforced composite material for automobile parts according to the present invention.
2 is a perspective view of a hybrid fiber-reinforced composite material for automobile parts according to Example 1 of the present invention.
3 is a perspective view of a hybrid fiber-reinforced composite material for automobile parts according to Example 2 of the present invention.
4 is a perspective view of a hybrid fiber-reinforced composite material for automobile parts according to Example 3 of the present invention.
5 is a perspective view of a hybrid fiber-reinforced composite material for automobile parts according to Example 4 of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a hybrid fiber-reinforced composite material for automobile parts according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The hybrid fiber-reinforced composite material for automobile parts of the present invention has a structure in which a long-fiber-reinforced thermoplastic resin sheet and a continuous fiber-reinforced thermoplastic resin sheet are laminated, and is superior to conventional long-fiber-reinforced thermoplastic resin composites or continuous fiber-reinforced thermoplastic resin composites. It can exhibit high strength, high strength and high rigidity.

The hybrid fiber-reinforced composite 100 according to the present invention includes at least one or more long fiber reinforced thermoplastic (LFT) sheets 10 and at least three or more continuous fiber reinforced thermoplastic (CFT) sheets. It includes a sheet 20 .

1 is a perspective view of a hybrid fiber-reinforced composite material for automobile parts according to the present invention. 1, the hybrid fiber-reinforced composite material for automobile parts according to the present invention is a long fiber reinforced thermoplastic (LFT) sheet 10 and a continuous fiber reinforced thermoplastic (CFT) sheet (20) represents a laminated structure.

Long fiber reinforced thermoplastic (LFT) sheet (10)

The long fiber-reinforced thermoplastic resin (LFT) sheet 10 refers to a sheet in which long fibers (not shown) are dispersed in a matrix formed of a first thermoplastic resin, and specifically, the first thermoplastic resin constitutes a base material, and therein It is a structure in which fibers are impregnated. This is a sheet whose strength is reinforced compared to a sheet formed only of a thermoplastic resin.

The long-fiber-reinforced thermoplastic resin (LFT) sheet 10 has excellent flowability and moldability compared to the continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 to be described later, so it is widely used as a material for automobile structures, and excellent in manufacturing composites. It can show machinability.

The first thermoplastic resin is a polypropylene-based resin, an aromatic vinyl-based resin, a rubber-modified aromatic vinyl-based resin, a polyphenylene ether-based resin, a polycarbonate-based resin, a polyester-based resin, a methacrylate-based resin, and a polyarylene sulfide. It may include at least one of a resin-based resin, a polyamide-based resin, and a polyvinyl chloride-based resin.

For example, the first thermoplastic resin may include a polypropylene-based resin, and the polypropylene-based resin is a polypropylene-based copolymer resin including a propylene-ethylene copolymer resin, a propylene-butene copolymer resin, and an ethylene-propylene-butene copolymer. resin may be included. When the first thermoplastic resin includes a polypropylene-based resin, it is easy to secure the weight reduction of the fiber-reinforced composite material.

The long fiber (not shown) is shorter than a continuous fiber and refers to a fiber cut to a predetermined length, and the long fiber may include at least one of glass fiber, carbon fiber, aramid fiber, and natural fiber. . Preferably, the long fiber has a length of 20 to 50 mm, and when the length of the long fiber exceeds this range, it is difficult to secure an appropriate level of rigidity and strength while the dispersibility of the long fiber is lowered, and a fiber-reinforced composite material is manufactured Formability may be deteriorated.

The long fiber-reinforced thermoplastic resin (LFT) sheet 10 may include 20 to 60 parts by weight of long fibers based on 100 parts by weight of the first thermoplastic resin. If the content of the long fiber is out of this range, it may be difficult to control the fluidity and moldability of the fiber-reinforced composite material, and the physical properties of the fiber-reinforced composite material may be deteriorated.

As such, the long fiber-reinforced thermoplastic resin (LFT) sheet 10 contains 20 to 60 parts by weight of long fibers having a length of 20 to 50 mm, and thus may satisfy a thickness range of 0.1 to 2 mm, and at least one or more long fiber reinforced thermoplastics. By including the resin (LFT) sheet 10 , the physical properties of the fiber-reinforced composite material 100 may be improved.

The long fibers included in the long fiber-reinforced thermoplastic resin (LFT) sheet 10 may have an orientation in a random direction or a single direction, and may have an orientation according to an extrusion direction. In general, the extrusion direction refers to the fiber direction, meaning that the angle formed with the orientation direction of the continuous fibers is parallel. Having the orientation in the random direction means that the long fiber single strands are arranged in a disorderly direction. Having the orientation in the single direction means that single strands of long fibers in the form of strands are arranged in any one direction. In addition, having orientation in a single direction includes cases in which the angle formed by two predetermined long fibers is 10° or less, specifically 5° or less, and is not only completely parallel to each other, but also difficult to identify with the naked eye. It should be understood that the margin of error of the degree is inclusive.

The long fiber-reinforced thermoplastic resin (LFT) sheet 10 including the first thermoplastic resin and long fibers may be manufactured by the following method.

First, the first thermoplastic resin is put into a compounding extruder, and reinforcing fibers extracted from a plurality of skeins of a roving type are put into the middle of the compounding extruder. Then, the reinforcing fibers are cut to a predetermined length and at the same time, the cut fibers and the preheated first thermoplastic resin are mixed. Then, the long fiber in the form of a strand is discharged, and the long fiber reinforced thermoplastic resin (LFT) sheet 10 is manufactured by compression and molding in a mold.

Continuous fiber reinforced thermoplastic (CFT) sheet (20)

The continuous fiber reinforced thermoplastic (CFT) sheet 20 refers to a sheet in which continuous fibers 22 are dispersed in a matrix formed of a second thermoplastic resin, and specifically, the second thermoplastic resin constitutes the base material. and fibers are impregnated therein. This is a sheet whose strength is reinforced compared to a sheet formed only of a thermoplastic resin.

The continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 may exhibit a higher strength than the long-fiber-reinforced thermoplastic resin (LFT) sheet 10 by including the continuous fibers 22 without a break. The continuous fiber 22 is a fiber reinforcement including at least one of glass fiber, carbon fiber, aramid fiber, and natural fiber, and exists in a continuous form without being broken therein depending on the final size of the fiber-reinforced composite material. means to do

For example, like continuous fibers in a UD sheet (unidirection sheet), the continuous fibers may be manufactured in a continuous process, and by continuously supplying the continuous fibers to this continuous process, a fiber-reinforced composite including continuous fibers is manufactured can do. Accordingly, the fiber-reinforced composite material may be manufactured into a product having a specific shape, such as a sheet, in which the continuous fibers have a specific range of length depending on the shape of the product. However, in that the length of this specific range can be arbitrarily adjusted in the manufacturing process in which the continuous fibers are continuously supplied, the continuous fibers should be regarded as having 'continuity', and most of the continuous fibers, such as continuous fibers in UD sheets or fabrics, are In this case, it has continuity without being broken inside the product.

Matters for the second thermoplastic resin are the same as described above for the first thermoplastic resin. In addition, as described above, the continuous fiber 22 may include at least one of glass fiber, carbon fiber, aramid fiber, and natural fiber.

The continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 may include 20 to 60 parts by weight of continuous fibers with respect to 100 parts by weight of the second thermoplastic resin. If the content of the continuous fibers 22 is out of this range, it may be difficult to exhibit high strength and high rigidity of the fiber-reinforced composite material, and the physical properties of the fiber-reinforced composite material may be deteriorated.

As such, as the continuous fiber-reinforced thermoplastic resin (CFT) sheet contains 20 to 60 parts by weight of continuous fibers, a thickness range of 0.1 to 2 mm may be satisfied, and at least three or more continuous fiber-reinforced thermoplastic resin (CFT) sheets 20 ) by including, it is possible to improve the physical properties of the fiber-reinforced composite material (100).

The continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 includes continuous fibers 22 having orientation in a single direction, and having orientation in a single direction means that the angle between two predetermined continuous fibers is 10° or less, Specifically, it should be understood to include a case of 5˚ or less, and an error range that is difficult to identify with the naked eye, as well as a state that is completely parallel to each other.

Hybrid fiber-reinforced composite material 100 for automobile parts of the present invention preferably includes at least three or more continuous fiber-reinforced thermoplastic resin (CFT) sheets 20, and by including at least three or more sheets 20, high strength And it is possible to secure the physical properties of high rigidity.

At this time, the other continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 adjacent to the orientation direction (d ₁ ) of the continuous fibers 22 included in one continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 is included in the sheet 20 It is preferable that the angle (θ) formed by the orientation direction (d _{2 ) of the continuous fiber 22 is 175° to 185°.} This means that the angle (θ) formed by single strands of continuous fibers included in different sheets is 175 to 185˚, meaning it is horizontal, and may include an angle range generally understood as horizontal.

1 to 5, the other continuous fiber-reinforced thermoplastic resin (CFT) sheet adjacent to the orientation direction of the continuous fibers 22 included in one continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 By forming the orientation direction of the continuous fibers 22 included in (20) to be horizontal, the hybrid fiber-reinforced composite 100 for automobile parts of the present invention by the force (modulus) to maintain the orientation direction of the continuous fibers is 200 MPa or more It can exhibit excellent flexural strength.

In particular, as shown in FIGS. 2, 3 and 5, when at least three or more continuous fiber-reinforced thermoplastic resin (CFT) sheets 20 are continuously laminated, the hybrid fiber-reinforced composite 100 for automobile parts is more excellent flexural strength. More specifically, at least three or more continuous fiber-reinforced thermoplastic resin (CFT) sheets 20 stacked in series may exhibit excellent flexural strength when disposed on the rear surface of the hybrid fiber-reinforced composite material 100 for automobile parts.

The continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 including the second thermoplastic resin and continuous fibers may be manufactured by the following method.

First, the second thermoplastic resin is put into the compounding extruder and melted at a temperature equal to or higher than the melting temperature of the second thermoplastic resin. The continuous fibers are pulled out from a plurality of skeins in the form of rovings and put into a mold. The second thermoplastic resin molten through the compounding extruder is put into the mold to be impregnated into the continuous fiber.

Then, it is pressed to cut it to an appropriate size, and by pressing using a calendar process, a continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 having excellent surface properties and controlling the single orientation of continuous fibers is produced. can be manufactured.

As described above, the hybrid fiber-reinforced composite material 100 for automobile parts includes a long fiber reinforced thermoplastic resin (LFT) sheet 10 and a continuous fiber reinforced thermoplastic resin (CFT) sheet 20, specifically continuous fibers The continuous fibers included in the reinforced thermoplastic resin (CFT) sheet 20 are oriented to have orientation in a single direction, and the orientation direction of the continuous fibers included in one continuous fiber reinforced thermoplastic (CFT) sheet and The angle formed by the orientation direction of the continuous fibers included in another adjacent continuous fiber reinforced thermoplastic (CFT) sheet forms 175 to 185˚, thereby exhibiting excellent strength and rigidity.

The hybrid fiber-reinforced composite 100 for automobile parts may have a flexural strength of 200 to 400 MPa according to ASTM D790. Flexural strength is the maximum strength generated from the specimen when the specimen is pressed at a constant speed, and can be measured by ASTM D790 method at room temperature of 23°C.

The automobile part may be, for example, a roof rack, a bumper backbeam, a seatback frame, a door beam, a tail gate, or a FEM carrier. can

As described above, specific examples of the hybrid fiber-reinforced composite material for automobile parts are as follows.

1. Manufacturing of hybrid fiber-reinforced composites for automobile parts

manufacturing example

According to the manufacturing method of the long fiber reinforced thermoplastic resin (LFT) sheet presented above, based on 100 parts by weight of the polypropylene resin, a long fiber reinforced thermoplastic resin containing 35 parts by weight of glass fiber (average length 20 mm, cross-sectional diameter 17 μm) ( LFT) sheet (A) was prepared.

The thickness of the long fiber reinforced thermoplastic resin (LFT) sheet (A) is 2 mm.

According to the manufacturing method of the continuous fiber-reinforced thermoplastic resin (CFT) sheet presented above, with respect to 100 parts by weight of the polypropylene resin, continuous fiber-reinforced thermoplastic comprising 35 parts by weight of glass fiber (cross-sectional diameter 17㎛) having orientation in one direction. A resin (CFT) sheet (B) was prepared.

The thickness of the continuous fiber-reinforced thermoplastic resin (CFT) sheet (B) is 2 mm.

Example 1

As shown in Figure 2, the sheet (A) and the sheet (B) according to the above manufacturing example are laminated, but stacked in a B/B/B/A structure from the top sheet, and included in one sheet (B). After laminating so that the orientation direction of the continuous fibers included in the other sheet (B) adjacent to the orientation direction of the continuous fibers is horizontal, and pressing at a pressure of 10 MPa, a hybrid fiber-reinforced composite material for automobile parts was prepared.

Example 2

As shown in FIG. 3, a hybrid fiber-reinforced composite for automobile parts was prepared in the same manner as in Example 1, except that the top sheet was laminated in an A/B/B/B structure.

Example 3

As shown in FIG. 4, a hybrid fiber-reinforced composite material for automobile parts was prepared in the same manner as in Example 1, except that the uppermost sheet was laminated in a B/A//B/A/B structure.

Example 4

As shown in FIG. 5, a hybrid fiber-reinforced composite material for automobile parts was prepared in the same manner as in Example 1, except that the uppermost sheet was laminated in an A//B/B/B/A structure.

Comparative Example 1

A hybrid fiber-reinforced composite material for automobile parts was prepared using only the long fiber-reinforced thermoplastic resin (LFT) sheet (A) according to Preparation Example.

2. Methods for evaluating physical properties and their results

Flexural strength: According to ASTM D790, the flexural strength was measured at room temperature of 23°C.

[Table 1] is a result showing the flexural strength (MPa) of the hybrid fiber-reinforced composite material for automobile parts of Examples 1 to 4 and Comparative Example 1.

[Table 1]

Referring to the results of [Table 1], the hybrid fiber-reinforced composites for automobile parts of Examples 1 to 4 show excellent results in flexural strength compared to the hybrid fiber-reinforced composites for automobile parts of Comparative Example 1.

In particular, as shown in FIGS. 3 and 5, when the continuous fiber-reinforced thermoplastic resin (CFT) sheet 20 is continuously laminated in three layers, and is disposed on the back side in the hybrid fiber-reinforced composite 100 for automobile parts, excellent at 300 MPa or more It can be seen that the flexural strength is represented.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, but may be manufactured in various different forms, and those of ordinary skill in the art to which the present invention pertains. It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

10: Long fiber reinforced thermoplastic resin (LFT) sheet
20: continuous fiber reinforced thermoplastic resin (CFT) sheet
22: continuous fiber
100: hybrid fiber-reinforced composite material for automobile parts

Claims (8)

at least one sheet of long fiber reinforced thermoplastic (LFT); and
Containing at least three or more continuous fiber reinforced thermoplastic (CFT) sheets;
The long fiber-reinforced thermoplastic resin (LFT) sheet includes a first thermoplastic resin and long fibers,
The continuous fiber-reinforced thermoplastic resin (CFT) sheet includes a second thermoplastic resin and continuous fibers having orientation in a single direction,
The continuous fiber-reinforced thermoplastic resin (CFT) sheet contains 20 to 60 parts by weight of continuous fibers with respect to 100 parts by weight of the second thermoplastic resin,
The angle between the orientation direction of the continuous fibers contained in one continuous fiber-reinforced thermoplastic resin (CFT) sheet and the orientation direction of the continuous fibers contained in the other continuous fiber-reinforced thermoplastic resin (CFT) sheet adjacent to each other is 175 to 185˚. Hybrid fiber-reinforced composite material, characterized in that.
According to claim 1,
Hybrid fiber-reinforced composite material, characterized in that at least three or more continuous fiber-reinforced thermoplastic resin (CFT) sheets are continuously laminated.
According to claim 1,
The long fiber-reinforced thermoplastic resin (LFT) sheet is a hybrid fiber-reinforced composite material, characterized in that the thickness is 0.1 ~ 2mm.
According to claim 1,
The continuous fiber-reinforced thermoplastic resin (CFT) sheet is a hybrid fiber-reinforced composite material, characterized in that the thickness is 0.1 ~ 2mm.
According to claim 1,
The long fiber-reinforced thermoplastic resin (LFT) sheet is a hybrid fiber-reinforced composite material, characterized in that it contains 20 to 60 parts by weight of long fibers based on 100 parts by weight of the first thermoplastic resin.
delete According to claim 1,
The long fiber-reinforced thermoplastic resin (LFT) sheet is a hybrid fiber-reinforced composite material, characterized in that it comprises long fibers having a length of 20 to 50 mm.
According to claim 1,
The hybrid fiber-reinforced composite material is a hybrid fiber-reinforced composite, characterized in that the flexural strength according to ASTM D790 is 200 ~ 400MPa.

Images