KR20180126762A - Hybrid type fiber reinforced composite material - Google Patents

Abstract

Disclosed is a hybrid fiber reinforced composite material which is excellent in impact absorption properties by adjusting an arrangement direction and a lamination design of fibers. According to the present invention, the hybrid fiber reinforced composite material includes a laminate consisting of at least one first sheet and at least one second sheet. The first sheet comprises a first thermoplastic resin and a long fiber oriented in a random direction or in a first single direction, and the second sheet comprises a second thermoplastic resin and a continuous fiber oriented in a second single direction, wherein an angle formed by the first single direction and the second single direction is 85-185°.

Description

HYBRID TYPE FIBER REINFORCED COMPOSITE MATERIAL [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced composite material, and more particularly, to a hybrid fiber-reinforced composite material in which a sheet containing long fibers and a sheet containing continuous fibers are laminated.

Lightweight and high strength fiber reinforced composite materials are used in various fields such as sports leisure structures such as golf clubs, structures such as telephone poles, automobile parts, and aircraft.

Fiber reinforced composite materials are composite materials using fibers as reinforcements, and they can control the mechanical properties of composites depending on the length, type, and orientation of the fibers.

For example, in the production of a composite material from a prepreg containing a fiber having unidirectionality, conventionally known composite materials have a limitation in improving the impact absorption property, while the reinforcing material is solely applied to thereby make it lightweight.

Therefore, it is necessary to produce a composite material having excellent light weight and impact strength characteristics by changing the structure of the fiber reinforced composite material.

As a background art related to the present invention, there is Korean Patent Laid-Open Publication No. 10-2016-0054661 (May 2015.057), which discloses an apparatus and a method for manufacturing a one-direction continuous fiber-reinforced thermoplastic composite material.

An object of the present invention is to provide a hybrid type fiber-reinforced composite material excellent in shock absorption properties.

According to an aspect of the present invention, there is provided a hybrid type fiber-reinforced composite material comprising a laminate of at least one first sheet and at least one second sheet, wherein the first sheet comprises a first thermoplastic resin and a random Direction or a first unidirectional orientation, wherein the second sheet comprises a second thermoplastic resin and a continuous fiber having an orientation in a second unidirectional direction, wherein the first unidirectional direction and the second unidirectional direction And the angle formed between them is 85 to 185 degrees.

The angle formed by the one direction and the second single direction may be 85 to 95 degrees.

The angle formed by the one direction and the second single direction may be 175 to 185 degrees.

The first sheet may include 20 to 70 parts by weight of long fibers with respect to 100 parts by weight of the first thermoplastic resin.

The second sheet may contain 20 to 70 parts by weight of continuous fibers per 100 parts by weight of the second thermoplastic resin.

The long fibers may have an average length of 10 to 30 mm.

The long fibers may include at least one of glass fiber, carbon fiber, aramid fiber and natural fiber.

The continuous fiber may include at least one of glass fiber, carbon fiber, aramid fiber and natural fiber.

The hybrid fiber-reinforced composite material may have an impact strength of 8 to 30 J / mm in accordance with ASTM D3763.

The hybrid type fiber-reinforced composite material according to the present invention is a structure in which a sheet containing long fibers and a sheet containing continuous fibers are laminated, and the direction of the fibers and the laminate design can be adjusted to improve the shock absorption property.

In addition, the hybrid fiber-reinforced composite material of the present invention can be applied to automobile and aircraft parts requiring high strength and high rigidity.

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

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

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

Generally, a fiber-reinforced composite material refers to a composite material using a fiber, which is a reinforcing material, and is a structure in which a base material containing a polymer resin is impregnated with fibers.

The present invention provides a hybrid fiber-reinforced composite material having a structure in which a first sheet including long fibers having excellent moldability and a second sheet including continuous fibers having excellent mechanical strength are laminated, The shock absorption characteristic can be improved.

Referring to Examples 1 to 5 of the present invention, the hybrid type fiber-reinforced composite material exhibits improved impact absorption properties than a fiber-reinforced composite material to which the first sheet or the second sheet alone is applied.

The hybrid type fiber-reinforced composite material of the present invention includes a laminate of at least one first sheet (10) and at least one second sheet (20).

The first sheet 10,

The first sheet is a sheet containing a first thermoplastic resin and a long fiber and has a structure in which long fibers are dispersed in a first thermoplastic resin matrix and is reinforced with a strength higher than that of a sheet formed only with a general thermoplastic resin.

The first sheet includes long fibers excellent in flowability and moldability as compared with continuous fibers, and can exhibit excellent processability in the production of a composite material. The long fiber means a fiber shorter than the continuous fiber and cut to a predetermined length.

The first sheet is a sheet containing a first thermoplastic resin and long fibers, and the long fibers have an orientation in a random direction or in a first single direction. Having orientation in the random direction means that the single strands of the long fibers are arranged in disordered directions. The orientation in the first unidirectional direction means that single strands of long fibers in the form of a strand are arranged in either direction.

The orientation in the first unidirection includes the case where the angle formed by the predetermined two long fibers is 10 degrees or less, specifically 5 degrees or less. In addition to the state where they are completely parallel to each other, It should be understood that the error range is difficult to be understood.

In the process of manufacturing the first sheet, long fibers having an orientation in the first unidirectional direction are pressed and formed in a metal mold. At this time, the strand is further oriented in the direction of spreading, and this direction is oriented in the machine direction . Therefore, having the orientation in the first unidirectional direction may mean that it is arranged in the MD direction or in any one direction.

The first sheet may be, for example, a long fiber reinforced thermoplastic sheet (LFT sheet) containing the long fibers in a matrix formed of a first thermoplastic resin.

The first thermoplastic resin may be a polypropylene resin, an aromatic vinyl resin, a rubber modified aromatic vinyl resin, a polyphenylene ether resin, a polycarbonate resin, a polyester resin, a methacrylate resin, a polyarylene sulfide Based resin, a polyamide-based resin, and a polyvinyl chloride-based resin.

For example, the first thermoplastic resin may include a polypropylene resin, and the polypropylene resin may be a propylene-ethylene copolymer resin, a propylene-butene copolymer resin, and an ethylene-propylene-butene copolymer Resin. When the thermoplastic resin contains a polypropylene-based resin, the fiber-reinforced composite material containing the thermoplastic resin can easily achieve a lightening effect.

The long fibers may include, for example, at least one of glass fiber, carbon fiber, aramid fiber and natural fiber.

The first sheet preferably comprises 20 to 70 parts by weight of the long fiber, more preferably 20 to 50 parts by weight, based on 100 parts by weight of the first thermoplastic resin. When the content of the long fibers is less than 20 parts by weight, the mechanical strength of the fiber-reinforced composite material is difficult to expect. When the content of the long fibers exceeds 70 parts by weight, the content of the long fibers increases, Can be lowered.

The long fibers preferably have an average length of 10 to 30 mm, more preferably 10 to 20 mm. If the average length of the long fibers is less than 10 mm, the manufacturing cost can be reduced, but the mechanical properties are deteriorated. On the other hand, if it exceeds 30 mm, the moldability is deteriorated.

The cross-sectional diameter of the long fibers may be 5 to 30 占 퐉. By satisfying the long fibers, the mechanical strength and moldability of the fiber-reinforced composite material can be secured.

The first sheet can be manufactured to have a thickness of approximately 0.1 to 10 mm by adjusting the average length, cross-sectional diameter, and content of the long fibers. In this range, excellent mechanical strength, formability, have.

The first sheet comprising the first thermoplastic resin and the long direction fibers in the random direction or in the first unidirectional direction can be produced by the following method.

First, a first thermoplastic resin is put into a compounding extruder, and reinforcing fibers extracted from a plurality of roving-type threads are put into an intermediate portion of the compounding extruder. Next, the reinforcing fibers are cut to a predetermined length, and the cut fibers are mixed with the preheated first thermoplastic resin. Then, strand-shaped long fibers are discharged, and the first sheet is produced by pressing and molding the long fibers in a mold.

The second sheet 20,

The second sheet is a sheet containing a second thermoplastic resin and continuous fibers, and is a sheet reinforced with a strength higher than that of a sheet formed only with a general thermoplastic resin.

The second sheet contains continuous fibers having excellent mechanical strength as compared with the long fibers, and can maintain the fiber orientation well and can exhibit excellent physical properties of the fiber reinforced composite material. The continuous fiber means that the continuous fiber is present in a continuous form without breaking in the fiber depending on the final size of the composite material to be produced, and the continuous fiber can be continuously supplied.

The second sheet is a sheet comprising a second thermoplastic resin and continuous fibers, and the continuous fibers have an orientation in a second single direction. The orientation in the second unidirectional direction (d2) means that the single stranded continuous fibers are arranged in a direction forming a predetermined angle (?) With the first unidirectional direction (d1).

The orientation in the second unidirection includes the case where the angle formed by two predetermined continuous fibers is 10 degrees or less, specifically 5 degrees or less. In addition to the state where they are perfectly parallel to each other, It should be understood that the error range is difficult to be understood.

More specifically, the angle formed by the first unidirectional direction d1 and the second unidirectional direction d2 may be 85 to 185 degrees. For example, the angle between the first unidirectional direction d1 and the second unidirectional direction d2 may be, (d2) may be 85 to 95 degrees. This angle means that the angle formed by the first unidirectional direction d1 and the second unidirectional direction d2 is perpendicular, and may include an angular range which is understood to be generally orthogonal. Also, for example, the angle formed by the first unidirectional direction d1 and the second unidirectional direction d2 may be 175 to 185 degrees, and the angle may be the angle between the first unidirectional direction d1 and the second unidirectional direction d2, (d2) is horizontal, and may include an angular range, which is generally understood to be horizontal.

The angle formed by the first unidirectional direction d1 and the second unidirectional direction d2 may be 85 to 95 degrees or 175 to 185 degrees and may include angles of 85 to 95 degrees and angles of 175 to 185 degrees It is possible.

The second sheet may comprise a continuous fiber thermoplastic sheet (CFT sheet), commonly called.

As described above, by controlling the orientation of the continuous fibers in the hybrid type fiber-reinforced composite material, it is possible to increase the strength in the fiber direction due to less bending of the fibers, and to exhibit excellent strength and rigidity in terms of structure.

The second thermoplastic resin may be a polypropylene resin, an aromatic vinyl resin, a rubber modified aromatic vinyl resin, a polyphenylene ether resin, a polycarbonate resin, a polyester resin, a methacrylate resin, a polyarylene sulfide Based resin, a polyamide-based resin, and a polyvinyl chloride-based resin.

For example, the second thermoplastic resin may include a polypropylene resin, and the polypropylene resin may be a propylene-ethylene copolymer resin, a propylene-butene copolymer resin, and an ethylene-propylene-butene copolymer Resin. When the thermoplastic resin contains a polypropylene-based resin, the fiber-reinforced composite material containing the thermoplastic resin can easily achieve a lightening effect.

The continuous fibers may include, for example, at least one of glass fiber, carbon fiber, aramid fiber and natural fiber.

The second sheet preferably comprises 20 to 70 parts by weight of continuous fibers, more preferably 20 to 40 parts by weight, per 100 parts by weight of the second thermoplastic resin. When the content of the continuous fibers is less than 20 parts by weight, it is difficult to control the orientation of the continuous fibers in the second sheet and the mechanical strength may be deteriorated. When the content of the continuous fibers exceeds 70 parts by weight, It may be difficult to show the weight reduction of the weight.

The second sheet can be manufactured to have a thickness of about 0.1 to 10 mm by controlling the content of the continuous fibers. In this range, excellent mechanical strength, formability, and shock absorption characteristics can be ensured.

The second sheet comprising the second thermoplastic resin and the continuous fiber can be produced by the following method.

For example, the second thermoplastic resin is put into a compounding extruder and melted at a temperature equal to or higher than the melting temperature of the second thermoplastic resin. Continuous fibers are pulled out of a plurality of rovings in the form of roving and put into a mold. And the melted second thermoplastic resin is injected into the mold through the compounding extruder to impregnate the continuous fiber.

The second sheet can then be produced by pressing it and cutting it to an appropriate size. More specifically, by pressing using a calendar process, It is possible to prepare a second sheet having excellent surface physical properties by controlling the unidirectional orientation of the continuous fibers.

Hybrid type fiber reinforced composite material (100)

The hybrid type fiber-reinforced composite material of the present invention comprises a laminate of at least one first sheet and at least one second sheet.

1 to 5 are perspective views showing hybrid type fiber-reinforced composite materials according to Examples 1 to 5 of the present invention.

As shown in Figs. 1 to 5, the hybrid type fiber-reinforced composite material of the present invention preferably has a structure in which a first sheet containing long fibers and a second sheet containing continuous fibers are alternately laminated one or more times , And more preferably two to five times.

In addition, the hybrid type fiber-reinforced composite material including long fibers and continuous fibers has an effect of not only high strength but also excellent weight reduction even when the fiber content is 20 to 70 parts by weight, more specifically 20 to 40 parts by weight.

The hybrid type fiber-reinforced composite material may have a fall impact strength of 8 to 30 J / mm measured according to the method of measuring the impact strength of the impact resistance (ASTM D3763 method).

Specific examples of the hybrid fiber-reinforced composite material will be described below.

1. Fabrication of Hybrid Type Fiber Reinforced Composites

Manufacturing example

According to the first sheet production method described above, a first sheet (first sheet) including 35 parts by weight of glass fibers (average length 30 mm, cross section diameter 20 mu m) oriented in the first uni-direction with respect to 100 parts by weight of the polypropylene resin A).

According to the above-described first sheet production method, a second sheet (B) comprising 35 parts by weight of glass fiber having orientation in the second unidirectional direction was provided for 100 parts by weight of the polypropylene resin.

Examples 1-5

As shown in FIGS. 1 to 5, the first sheet and the second sheet according to the production example were laminated and pressed to prepare a hybrid type fiber-reinforced composite material.

In Embodiment 1, the laminate has an A / B structure, and the angle formed by the first single direction and the second single direction is 180 degrees (horizontal).

In Embodiment 2, the laminate has an A / B / A structure, and the angle formed by the first single direction and the second single direction is 180 degrees (horizontal).

In the third embodiment, the laminate has the A / B / B / B structure, the angle formed by the first single direction and the second single direction from the uppermost layer is 180 degrees (horizontal), the angle formed by the first single direction and the second single direction (Vertical), and the angle formed by the first single direction and the second single direction is 180 degrees (horizontal).

In the fourth embodiment, the laminate has the A / B / B / B / A structure, the angle formed by the first single direction and the second single direction from the uppermost layer is 180 degrees (horizontal), the first single direction and the second single direction The angle formed is 90 ° (vertical), and the angle formed by the first single direction and the second single direction is 180 ° (horizontal).

In Embodiment 5, the laminate has a B / A / B / A / B structure, and the angle between the first unidirection and the second unidirection is 180 degrees (horizontal).

Comparative Example 1

Using only the first sheet according to the Production Example, a fiber-reinforced composite material was produced.

Comparative Example 2

Using only the second sheet according to the production example, a fiber-reinforced composite material was produced.

2. Property evaluation method and result

High / Speed Puncture Energy: According to ASTM D3763, the impact strength of the impact was measured at a room temperature of 23 캜. The fall weight was dropped on the composite material of Examples 1 to 5 and Comparative Examples 1 and 2 in the vertical direction to measure the crack generation energy from the height at which the crack occurred. Table 1 shows the results of the peak impact strength (J / mm).

[Table 1]

Referring to Table 1 and FIG. 1 to FIG. 5, it can be confirmed that the hybrid type fiber-reinforced composite material of the present invention exhibits excellent physical properties in terms of impact strength. In Example 1, the impact strength was improved by about 28% compared with Comparative Example 1 and Comparative Example 2, and in Example 5, the impact strength was improved by about 130%.

From these results, it can be seen that excellent mechanical strength and improved shock absorption characteristics can be secured by laminating a first sheet containing long fibers and a second sheet containing continuous fibers.

Particularly, as in Examples 4 and 5, when the first sheet and the second sheet were laminated two or more times and the continuous fibers were stacked in different directions, the shock absorption characteristics were more excellent.

Therefore, the hybrid type fiber-reinforced composite material of the present invention has an effect of not only stiffness and strength, but also impact absorption property, as compared with the fiber-reinforced composite material used as the first sheet or the second sheet alone. As described above, the hybrid type fiber-reinforced composite material of the present invention can exhibit high strength, excellent impact strength characteristics, and light weight and can be applied to automobile and aircraft parts.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

10: first sheet
20: second sheet
30: continuous fiber
100: Hybrid type fiber reinforced composite material

Claims (9)

A laminate of at least one first sheet and at least one second sheet,
Wherein the first sheet comprises a first thermoplastic resin and a long fiber oriented in a random direction or in a first unidirectional direction,
Wherein the second sheet comprises a second thermoplastic resin and a continuous fiber having a second unidirectional orientation,
Wherein the angle formed by the first single direction and the second single direction is 85 to 185 degrees.
The method according to claim 1,
Wherein the angle formed by the first single direction and the second single direction is 85 to 95 degrees.
The method according to claim 1,
Wherein the angle formed by the first single direction and the second single direction is between 175 and 185 degrees.
The method according to claim 1,
Wherein the first sheet comprises 20 to 70 parts by weight of long fibers per 100 parts by weight of the first thermoplastic resin.
The method according to claim 1,
Wherein the second sheet comprises 20 to 70 parts by weight of continuous fibers per 100 parts by weight of the second thermoplastic resin.
The method according to claim 1,
Wherein the long fibers have an average length of 10 to 30 mm.
The method according to claim 1,
Wherein the long fibers include at least one of glass fiber, carbon fiber, aramid fiber and natural fiber.
The method according to claim 1,
Wherein the continuous fiber comprises at least one of glass fiber, carbon fiber, aramid fiber and natural fiber.
The method according to claim 1,
The hybrid type fiber-reinforced composite material according to claim 1, wherein the hybrid type fiber-reinforced composite material has an impact strength of 8 to 30 J / mm in accordance with ASTM D3763.

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