KR102267884B1 - Hybrid type fiber reinforced composite material - Google Patents

Abstract

Disclosed is a hybrid type fiber-reinforced composite material having excellent shock absorption properties by controlling the fiber arrangement direction and lamination design.
The hybrid fiber-reinforced composite material according to the present invention includes a laminate of at least one first sheet and at least one second sheet, wherein the first sheet is oriented in a random direction or a first single direction with a first thermoplastic resin. and a long fiber having a, wherein the second sheet includes a second thermoplastic resin and a continuous fiber having an orientation in a second single direction, and the angle between the first single direction and the second single direction is 85 to 185˚ characterized by being.

Description

Hybrid type fiber-reinforced composite material {HYBRID TYPE FIBER REINFORCED COMPOSITE MATERIAL}

The present invention relates to a fiber-reinforced composite material, and more particularly, to a hybrid-type fiber-reinforced composite material in which a sheet including long fibers and a sheet including continuous fibers are laminated.

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

Fiber-reinforced composite material refers to a composite material using fibers as a reinforcing material, and the mechanical properties of the composite material can be adjusted according to the length, type, and orientation of the fibers.

For example, a composite material is manufactured from a prepreg containing fibers having a single orientation, and the conventionally known composite material has an excellent weight saving effect because the reinforcing material is applied alone, but there is a limit in improving the impact absorption property.

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

As a background art related to the present invention, there is Republic of Korea Patent Publication No. 10-2016-0054661 (2016.05.17.), which discloses an apparatus and method for manufacturing a unidirectional continuous fiber-reinforced thermoplastic composite material.

It is an object of the present invention to provide a hybrid fiber-reinforced composite material having excellent shock absorption properties.

Hybrid fiber-reinforced composite material according to the present invention for achieving the above object includes a laminate of at least one first sheet and at least one or more second sheets, wherein the first sheet is a first thermoplastic resin and random a long fiber having orientation in a direction or a first single direction, wherein the second sheet comprises a second thermoplastic resin and continuous fibers having an orientation in a second single direction, the first single direction and the second single direction The angle formed by this is characterized in that 85 ~ 185˚.

An angle between the first direction and the second single direction may be 85° to 95°.

An angle between the first direction and the second single direction may be 175° to 185°.

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

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

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

The long fiber 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 a falling ball impact strength of 8 to 30 J/mm according to ASTM D3763.

The hybrid fiber-reinforced composite material according to the present invention has a structure in which a sheet including a long fiber and a sheet including a continuous fiber are laminated, and the shock absorption characteristics can be improved by controlling the arrangement direction and the stacking design of the fibers.

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

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

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 the possessor of 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 according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In general, a fiber-reinforced composite material refers to a composite material using fibers as a reinforcement, and has a structure in which fibers are impregnated into a base material containing a polymer resin.

The present invention provides a hybrid fiber-reinforced composite material having a structure in which a first sheet containing long fibers having excellent formability and a second sheet containing continuous fibers having excellent mechanical strength are laminated, It is possible to improve the shock absorption properties.

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

The hybrid 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 .

first sheet (10)

The first sheet is a sheet including a first thermoplastic resin and long fibers, has a structure in which long fibers are dispersed in the first thermoplastic resin matrix, and has a stronger strength than a sheet formed only of a general thermoplastic resin.

The first sheet may exhibit excellent processability when manufacturing a composite material, including long fibers having superior flowability and formability compared to continuous fibers. The long fiber is shorter than the continuous fiber and refers to a fiber cut to a predetermined length.

The first sheet is a sheet including a first thermoplastic resin and long fibers, and the long fibers have orientation in a random direction or a first single direction. 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 first 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 the first 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 identified when viewed with the naked eye. It should be understood that an error range that is difficult to perform is included.

In the process of manufacturing the first sheet, long fibers having orientation in the first single direction are compressed and molded in a mold, and at this time, they have more orientation in the direction in which the strands are spread, and this direction is MD (Machine direction) direction. It is said Accordingly, having the orientation in the first single direction may mean being 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) in which the long fibers are included in a matrix formed of a first thermoplastic resin.

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 thermoplastic resin includes a polypropylene-based resin, the fiber-reinforced composite material including the same can easily secure a weight reduction effect.

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

The first sheet preferably contains 20 to 70 parts by weight of long fibers, 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 fiber is less than 20 parts by weight, it is difficult to expect the mechanical strength of the fiber-reinforced composite material, and when it exceeds 70 parts by weight, it is difficult to secure the weight reduction of the fiber-reinforced composite material as the content of the long fiber increases, and the formability this may be lowered.

The long fibers preferably have an average length of 10 to 30 mm, more preferably 10 to 20 mm. When the average length of the long fibers is less than 10 mm, the manufacturing cost can be reduced, but there is a problem in that mechanical properties are deteriorated. Conversely, when it exceeds 30 mm, there is a problem in that the formability is deteriorated.

In addition, the cross-sectional diameter of the long fiber may be 5 to 30 μm, and when the long fiber satisfies this range, mechanical strength and moldability of the fiber-reinforced composite material may be secured.

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

The first sheet including the first thermoplastic resin and long fibers having an orientation in a random direction or a first single direction 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 part 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, a long fiber in the form of a strand is discharged, and the first sheet is manufactured by pressing and molding it in a mold.

2nd sheet (20)

The second sheet is a sheet including a second thermoplastic resin and continuous fibers, and is a sheet having a stronger strength than a sheet formed only of a general thermoplastic resin.

The second sheet, including continuous fibers having superior mechanical strength compared to the long fibers, can maintain the orientation of the fibers and exhibit excellent physical properties of the fiber-reinforced composite material. The continuous fiber means that it exists in a continuous form without being broken inside it depending on the final size of the composite material to be manufactured, and the continuous fiber may be continuously supplied and manufactured.

The second sheet is a sheet including a second thermoplastic resin and continuous fibers, and the continuous fibers have orientation in a second single direction. Having the orientation in the second single direction d2 means that the single strands of the continuous fibers are arranged in a direction forming a predetermined angle θ with the first single direction d1.

In addition, having orientation in the second single direction includes cases in which the angle formed by two predetermined continuous fibers is 10° or less, specifically 5° or less, and is not only completely parallel to each other, but also identified when viewed with the naked eye. It should be understood that an error range that is difficult to perform is included.

More specifically, the angle between the first single direction d1 and the second single direction d2 may be 85° to 185°, for example, the first single direction d1 and the second single direction d2 The angle formed by (d2) may be 85 to 95˚. This angle means that the angle formed by the first single direction d1 and the second single direction d2 is vertical, and may include an angle range that is generally understood to be orthogonal. Also, for example, an angle between the first single direction d1 and the second single direction d2 may be 175° to 185°, and this angle is between the first single direction d1 and the second single direction d1. It means that the angle formed by (d2) is horizontal, and may include an angle range generally understood as horizontal.

As such, the angle between the first single direction d1 and the second single direction d2 may be 85 to 95° or 175 to 185°.

The second sheet may include a generally called continuous fiber thermoplastic sheet (CFT sheet).

As such, by controlling the orientation of the continuous fibers in the hybrid-type fiber-reinforced composite material, the bending of the fibers is small, the strength in the fiber direction can be increased, and structurally excellent strength and rigidity can be exhibited.

The second 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 second 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 thermoplastic resin includes a polypropylene-based resin, the fiber-reinforced composite material including the same can easily secure a weight reduction effect.

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

The second sheet preferably contains 20 to 70 parts by weight of continuous fibers, more preferably 20 to 40 parts by weight, based on 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 lowered, and when it exceeds 70 parts by weight, the content of the continuous fibers increases and the fiber-reinforced composite material It may be difficult to indicate the weight reduction of

The second sheet may be manufactured to have a thickness of approximately 0.1 to 10 mm by controlling the content of the continuous fibers, and excellent mechanical strength, formability, and shock absorption properties may be secured within this range.

The second sheet including the second thermoplastic resin and continuous fibers may be manufactured by the following method.

For example, 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, the second sheet can be manufactured by pressing it and cutting it to an appropriate size. Specifically, by pressing using a calendar process, It is possible to control the single orientation of the continuous fibers and to prepare a second sheet having excellent surface properties.

Hybrid Fiber Reinforced Composite Material (100)

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

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

1 to 5, the hybrid fiber-reinforced composite material of the present invention preferably has a structure in which a first sheet including long fibers and a second sheet including continuous fibers are alternately stacked at least once. And, it is more preferable that the structure is laminated 2 to 5 times.

In addition, the hybrid type fiber-reinforced composite material including long fibers and continuous fibers has an effect of exhibiting excellent weight reduction as well as high strength only with a fiber content of 20 to 70 parts by weight, more specifically, 20 to 40 parts by weight.

The hybrid fiber-reinforced composite material may have a falling ball impact strength of 8 to 30 J/mm measured according to a falling ball impact strength measurement method (ASTM D3763 method).

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

1. Preparation of hybrid fiber-reinforced composite materials

manufacturing example

According to the manufacturing method of the first sheet presented above, based on 100 parts by weight of the polypropylene resin, a first sheet comprising 35 parts by weight of glass fiber (average length 30mm, cross-sectional diameter 20㎛) having orientation in the first single direction ( A) was prepared.

According to the manufacturing method of the first sheet presented above, with respect to 100 parts by weight of the polypropylene resin, a second sheet (B) including 35 parts by weight of glass fibers having orientation in the second single direction was prepared.

Examples 1 to 5

1 to 5, after laminating and pressing the first sheet and the second sheet according to the above preparation example, a hybrid fiber-reinforced composite material was prepared.

In Example 1, the laminate has an A/B structure, and the angle between the first single direction and the second single direction is 180° (horizontal).

In Example 2, the laminate has an A/B/A structure, and the angle between the first single direction and the second single direction is 180° (horizontal).

In Example 3, the laminate has an A/B/B/B structure, and the angle between the first single direction and the second single direction from the uppermost layer is 180° (horizontal), and the angle between the first single direction and the second single direction is 90˚ (vertical), and the angle between the first single direction and the second single direction is 180˚ (horizontal).

In Example 4, the laminate has an A/B/B/B/A structure, and the angle between the first single direction and the second single direction from the uppermost layer is 180° (horizontal), and the first single direction and the second single direction are The angle formed is 90˚ (vertical), and the angle formed between the first single direction and the second single direction is 180˚ (horizontal).

In Example 5, the laminate has a B/A/B/A/B structure, and the angle between the first single direction and the second single direction is 180° (horizontal).

Comparative Example 1

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

Comparative Example 2

Using only the second sheet according to Preparation Example, a fiber-reinforced composite material was prepared.

2. Methods for evaluating physical properties and their results

Falling ball impact strength (High/Speed Puncture Energy): In accordance with ASTM D3763, the falling ball impact strength was measured at room temperature of 23°C. A drop weight was dropped on the composite materials of Examples 1 to 5 and Comparative Examples 1 and 2 in the vertical direction, and the crack generation energy was converted from the crack generation height and measured. Table 1 is a result showing the falling ball impact strength (J / mm).

[Table 1]

Referring to Table 1 and FIGS. 1 to 5, it can be seen that the hybrid fiber-reinforced composite material of the present invention exhibits excellent physical properties in terms of falling ball impact strength. In Example 1, the impact strength was improved by approximately 28% compared to Comparative Examples 1 and 2, and in Example 5, the impact strength was improved by approximately 130%.

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

In particular, as in Examples 4 and 5, by laminating the first sheet and the second sheet two or more times, and stacking the continuous fibers 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 superior to that of the fiber-reinforced composite material used alone as the first sheet or the second sheet, as well as in stiffness and strength, as well as in shock absorption. As such, the hybrid fiber-reinforced composite material of the present invention can exhibit high strength, excellent impact strength characteristics, and weight reduction, and thus can be applied to automobile and aircraft parts.

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: first sheet
20: second sheet
30: continuous fiber
100: hybrid type fiber-reinforced composite material

Claims (9)

Comprising a laminate of at least one or more first sheets and at least one or more second sheets,
The first sheet includes a first thermoplastic resin and a long fiber having orientation in a first single direction,
The second sheet includes a second thermoplastic resin and continuous fibers having orientation in a second single direction,
The angle between the first single direction and the second single direction is 85 to 95˚ or 175 to 185˚,
The long fibers have an average length of 10 to 30 mm,
A hybrid fiber-reinforced composite material having an impact strength of 8 to 30 J/mm according to ASTM D3763.
delete delete According to claim 1,
The first sheet is a hybrid fiber-reinforced composite material, characterized in that it contains 20 to 70 parts by weight of long fibers with respect to 100 parts by weight of the first thermoplastic resin.
According to claim 1,
The second sheet is a hybrid fiber-reinforced composite material, characterized in that it contains 20 to 70 parts by weight of continuous fibers with respect to 100 parts by weight of the second thermoplastic resin.
delete According to claim 1,
The long fiber is a hybrid fiber-reinforced composite material, characterized in that it comprises at least one of glass fiber, carbon fiber, aramid fiber and natural fiber.
According to claim 1,
The continuous fiber is a hybrid fiber-reinforced composite material, characterized in that it comprises at least one of glass fiber, carbon fiber, aramid fiber and natural fiber.
delete

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