KR102362201B1 - Fiber reinforced composite material with uniform surface - Google Patents

Abstract

A fiber-reinforced composite material having a uniform surface is provided. The fiber-reinforced composite material may include a non-bend laminate comprising non-crimp fabric (NCF) sheets, at least one woven sheet disposed on the non-bend laminate and a non-woven fabric disposed on the at least one woven sheet. Includes sheet.
wherein at least one of a top layer and a bottom layer comprises one of the NCF sheets, and wherein the at least one woven sheet is disposed on at least one of the top layer and the bottom layer of the non-bend laminate. are placed
The nonwoven sheet may improve the surface uniformity of the fiber-reinforced composite material.

Description

Fiber-reinforced composite material with uniform surface

The present invention relates to a fiber-reinforced composite material having a uniform surface.

Fiber-reinforced composite materials are being used as a replacement for metals. A fiber-reinforced composite material is a material that exhibits a function that cannot be obtained by combining two or more materials alone. Glass fiber (GF) or carbon fiber (CF), etc. are widely used fiber reinforcement materials, and thermosetting resins or thermoplastic resins are used as resin base materials.

Since the continuous fiber-reinforced composite may contain a higher content of fiber reinforcement compared to the short-fiber-reinforced composite and the long-fiber-reinforced composite, it is possible to exhibit a higher level of mechanical properties compared to these.

A woven fabric is a structure in which weft and warp yarns cross each other up and down. The inventors of the present application, in the process of developing a fiber-reinforced composite material by combining non-crimp fabric (NCF) sheets and a woven fabric sheet, a woven fabric in the outermost region of a laminate of fabric sheets It was confirmed that the surface uniformity of the fiber-reinforced composite material was lowered when the sheet was disposed.

An object of the present invention is to provide a fiber-reinforced composite material with improved surface uniformity even when a woven fabric sheet is provided in the outermost region of a laminate of fabric sheets.

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

The fiber-reinforced composite material according to the present invention includes a laminate of fabric sheets, a non-woven fabric sheet, and a resin.

The laminate of woven sheets includes an unbend laminate and at least one woven sheet. The non-bend laminate includes non-crimp fabric (NCF) sheets, and at least one of an uppermost layer and a lowermost layer is constituted by one of the NCF sheets.

The at least one sheet of woven fabric includes weft and warp yarns and is disposed on at least one of the uppermost layer and the lowermost layer of the unbend laminate.

The nonwoven sheet is intertwined with irregularly oriented discontinuous fibers and is disposed on the at least one sheet of woven fabric.

The resin is impregnated into the NCF sheets, the at least one woven sheet and the at least one nonwoven sheet.

The NCF sheets, the weft and the warp each include continuous reinforcing fibers oriented in one direction, and the unidirectional orientation direction of the continuous reinforcing fibers of the weft yarn and the unidirectional orientation directions of the continuous reinforcing fibers of the warp yarn are alternated with each other.

The non-woven fabric sheet may serve to planarize the valleys of the woven fabric sheet. Discontinuous fibers oriented in the negative direction planarize the valleys of the woven fabric sheet, so that the present invention can provide a fiber-reinforced composite material with improved surface uniformity.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a schematic cross-sectional view of a fiber-reinforced composite material according to the present invention.
2 is a schematic diagram of a woven fabric sheet.
3 is a measurement image of the surface uniformity of the fiber-reinforced composite material according to the embodiment.
4 is an image of measuring the surface uniformity of a fiber-reinforced composite material according to a comparative example.

Advantages and features of the invention, and a method for achieving them will become apparent with reference to the embodiments and experimental examples described below in detail in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are only for easy understanding of the spirit of the technology disclosed in this specification, and should not be construed as limiting the spirit of the technology by the accompanying drawings.

In addition, the invention is not limited to the content disclosed below, but can be implemented in various forms, and the content disclosed below allows the disclosure of the invention to be complete, and the invention is provided to those of ordinary skill in the art to which the invention pertains. It is provided to fully indicate the scope of the invention, and the invention is only defined by the scope of the claims.

When it is determined that a detailed description of a related known technology may obscure the gist of the technology, the detailed description may be omitted. Like reference numerals refer to like elements throughout. Sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of description.

Although the first, second, etc. are used to describe various elements, these elements are not limited by these terms, of course. These terms are only used to distinguish one component from other components, and unless otherwise stated, it goes without saying that the first component may be the second component.

Throughout the specification, unless otherwise stated, each element may be singular or plural. Throughout the specification, when a part refers to "including" or "having" a certain element, it does not exclude other elements, but adds other elements unless otherwise stated. means that it can contain

Throughout the specification, when “A and/or B” is used, it means A, B or A and B, unless otherwise stated, and when “C to D” is used, it means that there is no specific opposite description. Unless otherwise specified, it means that it is greater than or equal to C and less than or equal to D.

Spatially relative terms "below", "beneath", "lower", "above", "upper", etc. It can be used to easily describe the correlation between an element or components and other elements or components. The spatially relative terms should be understood as terms including different orientations of the device during use or operation in addition to the orientation shown in the drawings.

1 is a schematic cross-sectional view of the fiber-reinforced composite material 100 is shown, Figure 2 is a schematic diagram of the woven fabric sheet (2P) is shown. The fiber-reinforced composite material 100 will be described with reference to FIGS. 1 and 2 .

The fiber-reinforced composite material 100 includes a laminate (1P, 2P) of fabric sheets, at least one non-woven fabric sheet (NW), and a resin (P). The stack of fabric sheets includes an unbend stack 1P and at least one woven fabric sheet 2P. The non-bend laminate 1P includes NCF sheets n, n+1, n+2. The resin P is impregnated into the NCF sheets n, n+1, n+2, at least one woven fabric sheet 2P, and at least one nonwoven fabric sheet NW, respectively.

The fiber-reinforced composite material 100 may include a first layer, a second layer, and a third layer, wherein the first layer includes the non-bend laminate 1P, and the second layer includes at least Includes one woven fabric sheet (2P). The third layer comprises at least one nonwoven sheet NW.

The first layer includes a non-bending laminate 1P and a resin P impregnated in the non-bending laminate 1P, and the non-bending laminate 1P is a non-crimp fabric (NCF). ) sheets (n, n+1, n+2). In the NCF sheets (n, n+1, n+2), the NCF sheet (n), the NCF sheet (n+1) and the NCF sheet (n+2) illustrate NCF sheets disposed adjacent to each other, Although three NCF sheets (n, n+1, n+2) are exemplarily shown in FIG. 1 , the number of NCF sheets included in the non-bend laminate 1P is three as shown in FIG. 1 . not limited

The NCF sheets n, n+1, n+2 each include continuous reinforcing fibers 1 oriented in one direction. Among the NCF sheets, any first NCF sheet and any second NCF sheet disposed adjacent to each other may satisfy the following condition.

When the unidirectional orientation direction of the continuous reinforcing fibers of the first NCF sheet is referred to as the first direction, and the unidirectional orientation direction of the continuous reinforcing fibers of the second NCF sheet is referred to as the second direction, the first direction is the fiber-reinforced composite material (100) may have an angle of +θ° with respect to the reinforcement required direction of the article to which is applied, and the second direction is an angle of -θ° with respect to the direction of reinforcement required for the article to which the fiber-reinforced composite material 100 is applied. can have In this case, θ° may be 1° to 44°.

The 'reinforcement demand direction' means when the article to which the fiber-reinforced composite material 100 is applied is mounted on a vehicle or aircraft, or when the vehicle or aircraft operates and moves after installation, considering the external force or load applied from the outside. and a predetermined direction in which rigidity needs to be supplemented. The direction of the reinforcement demand can be determined by the restraint position and installation conditions when the article to which the fiber-reinforced composite material 100 is applied is mounted on it as a part such as a vehicle or aircraft, and most importantly, strength and rigidity need to be supplemented. It means the direction of work.

For example, when the first NCF sheet is the NCF sheet (n) and the second NCF sheet is the NCF sheet (n+1), the one-way orientation direction (DR1) of the continuous reinforcing fibers 1 of the NCF sheet (n) is crossed with the one-way orientation direction (DR2) of the continuous reinforcing fibers (1) of the NCF sheet (n+1). Specifically, the intersection angle between the unidirectional orientation direction (DR1) of the continuous reinforcing fibers (1) of the NCF sheet (n) and the unidirectional orientation direction (DR2) of the continuous reinforcing fibers (1) of the NCF sheet (n+1) is 30° to 90°.

For example, when the first NCF sheet is an NCF sheet (n+1) and the second NCF sheet is an NCF sheet (n+2), one-way orientation of the continuous reinforcing fibers 1 of the NCF sheet (n+1) The direction DR2 crosses the one-way orientation direction DR3 of the continuous reinforcing fibers 1 of the NCF sheet n+2. Specifically, the intersection angle between the unidirectional orientation direction (DR2) of the continuous reinforcing fibers (1) of the NCF sheet (n+1) and the unidirectional orientation direction (DR3) of the continuous reinforcing fibers (1) of the NCF sheet (n+2) is It may be 30° to 90°.

At least one of the uppermost layer and the lowermost layer of the non-bending laminate 1P is made of an NCF sheet. At least one NCF sheet may be interposed as an intermediate layer between the uppermost layer and the lowermost layer of the non-bending laminate 1P. For example, when the non-bend laminate 1P includes NCF sheets n, n+1, n+2, the uppermost layer of the non-bend laminate 1P may be an NCF sheet n, The lowermost layer of the non-bending laminate 1P may be an NCF sheet (n+2), and the intermediate layer may include an NCF sheet (n+1).

The continuous reinforcing fiber 1 has an advantage in that it is easy to control the orientation in a single direction, unlike the short fiber reinforcing fiber or the long fiber reinforcing fiber. In addition, the continuous reinforcing fiber 1 may significantly improve the flexibility and impact resistance of the NCF sheets n, n+1, and n+2 compared to the short fiber reinforcing fiber or the long fiber reinforcing fiber. The continuous reinforcing fiber 1 may be classified into glass fiber, carbon fiber, aramid fiber, polypropylene fiber, polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene fiber, natural fiber, etc. according to the material.

The continuous reinforcing fiber 1 may be an aggregate made by gathering single strands of fibers. The single strand of the continuous reinforcing fiber 1 has a cross-sectional diameter of, for example, from about 1 μm to about 200 μm, from about 1 μm to about 50 μm, from about 1 μm to about 30 μm, or from about 1 μm to about 20 μm. μm. A single strand of the continuous reinforcing fibers 1 may have an excellent unidirectional orientation by having a cross-sectional diameter within the above range.

1 and 2 , the second layer is disposed on the first layer, and the second layer is disposed on any one of the uppermost layer and the lowermost layer of the non-bend laminate 1P, and the weft yarn WT. and at least one woven fabric sheet (2P) including warp yarns (HT) and a resin (P) impregnated in at least one woven fabric sheet (2P). Fig. 1 illustrates a case in which one woven fabric sheet 2P is disposed on the NCF sheet n of the uppermost layer of the non-bend laminate 1P. The second layer may be composed of a single layer of the woven fabric sheet (2P), it may be composed of a laminate of the woven fabric sheet (2P). The woven fabric sheet 2P may be a twill fabric sheet, for example, may have a twill pattern.

The weft yarn WT and the warp yarn HT include continuous reinforcing fibers 1 oriented in one direction. The continuous reinforcing fiber 1 has an advantage in that it is easy to control the orientation in a single direction, unlike the short fiber reinforcing fiber or the long fiber reinforcing fiber. In addition, the continuous reinforcing fiber 1 can significantly improve the flexibility and impact resistance of the woven fabric sheet 2P compared to the short fiber reinforcing fiber or the long fiber reinforcing fiber. The continuous reinforcing fiber 1 may be classified into glass fiber, carbon fiber, aramid fiber, polypropylene fiber, polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene fiber, natural fiber, etc. according to the material.

The continuous reinforcing fiber 1 may be an aggregate made by gathering single strands of fibers. The single strand of the continuous reinforcing fiber 1 has a cross-sectional diameter of, for example, from about 1 μm to about 200 μm, from about 1 μm to about 50 μm, from about 1 μm to about 30 μm, or from about 1 μm to about 20 μm. μm. A single strand of the continuous reinforcing fibers 1 may have an excellent unidirectional orientation by having a cross-sectional diameter within the above range.

The weft yarn WT and the warp yarn HT may each have a width of about 0.5 mm to about 20 mm, and about 3 mm to about 10 mm. When the width of the weft yarn WT and the warp yarn HT is too narrow, there is a risk that the physical properties of the woven fabric sheet 2P may be lowered because the bends generated while configuring the weaving form increase, and if the width is too wide, There is a possibility that the reinforcing effect due to the structure oriented at a predetermined angle may not be sufficient.

In addition, the weft yarn (WT) and the warp yarn (HT) may have a thickness of about 50 μm to about 10000 μm, about 50 μm to about 2000 μm, and about 50 μm to about 1000 μm, respectively. The thickness of the weft yarn (WT) and the warp yarn (HT) respectively satisfy the above-mentioned range, and at the same time satisfy the above-described thickness range, so that it is possible to easily secure the effect of reinforcing the strength or rigidity of the woven sheet 2P.

In order to evenly distribute the external force applied to the woven fabric sheet 2P, the weft yarn WT and the warp yarn HT have a unidirectional orientation direction of the continuous reinforcing fibers 1 staggered from each other.

When the orientation direction of the continuous reinforcing fibers 1 of the warp yarn HT is referred to as a first direction and the orientation direction of the continuous reinforcing fibers 1 of the weft yarn WT is referred to as the second direction, the first direction is, for example, , it may be any one of the longitudinal direction (D1 in FIG. 2), the width direction and the diagonal direction of the weft thread (WT). The second direction may be any one of a longitudinal direction (D2 in FIG. 2 ), a width direction, and an oblique direction of the warp yarn HT.

The first direction may have an angle of +θ° with respect to the reinforcement required direction of the article to which the fiber-reinforced composite material 100 is applied, and the second direction is the direction of the article to which the fiber-reinforced composite material 100 is applied. It can have an angle of -θ° with respect to the reinforcement request direction. In this case, θ° may be 1° to 44°. For example, the intersection angle between the orientation direction of the continuous reinforcing fibers 1 of the warp yarn HT and the orientation direction of the continuous reinforcing fibers 1 of the weft yarn WT may be 30° to 90°.

The 'reinforcement demand direction' means when the article to which the fiber-reinforced composite material 100 is applied is mounted on a vehicle or aircraft, or when the vehicle or aircraft operates and moves after installation, considering the external force or load applied from the outside. and a predetermined direction in which rigidity needs to be supplemented. The direction of the reinforcement demand can be determined by the restraint position and installation conditions when the article to which the fiber-reinforced composite material 100 is applied is mounted on it as a part such as a vehicle or aircraft, and most importantly, strength and rigidity need to be supplemented. It means the direction in which there is.

The third layer includes a nonwoven fabric sheet (NW) in which discontinuous fibers are entangled and a resin (P) impregnated in the nonwoven fabric sheet (NW), and is disposed on the second layer. Discontinuous fibers oriented in the negative direction may serve to planarize the troughs H of the woven fabric sheet 2P. The nonwoven fabric sheet NW may improve the surface uniformity of the fiber-reinforced composite material 100 .

When the porosity of the nonwoven fabric sheet (NW) is insufficient, compared to the case where the nonwoven fabric sheet (NW) is not used, the impregnation property of the resin (P) is further lowered, so that the surface uniformity of the fiber-reinforced composite material 100 is further reduced. Therefore, it is preferable that the nonwoven fabric sheet NW has porosity so that the flowability of the resin P is improved and the nonwoven fabric sheet NW can serve as a flow medium.

Glass fibers are an example of discontinuous fibers. The nonwoven sheet NW may have a structure in which long glass fibers oriented in a negative direction are entangled with each other and a binder is coated on the surfaces of the glass fibers. As an example of the nonwoven fabric sheet NW, a glass veil, a glass mat, etc. are mentioned.

The nonwoven fabric sheet (NW) preferably has a refractive index similar to that of the resin (P) in order to prevent deterioration of the surface quality of the fiber-reinforced composite material 100 due to diffuse reflection by the long glass fibers. For example, when the refractive index of the resin (P) is 1, the refractive index of the nonwoven sheet (NW) compared to the refractive index of the resin (P) may be 0.9 to 1.1.

By controlling the refractive index of the glass veil to 0.9 to 1.1 compared to the refractive index of the resin (P), it is possible to prevent the glass filaments from being exposed on the surface of the fiber-reinforced composite material 100, and due to the diffuse reflection by the long glass fibers It is possible to prevent deterioration of the surface quality of the fiber-reinforced composite material 100 . For example, when the resin (P) is composed of an epoxy resin having a refractive index of 1.50, the binder contains a thiol group having a refractive index of 1.62, so that the refractive index of the nonwoven fabric sheet (NVW) is equal to that of the resin (P). A similar level of control is possible.

The glass veil may have a basis weight of 30 g/m ² to 50 g/m ² to improve the drapeability of the fiber-reinforced composite material 100 . In addition, in order to increase the impregnability with the resin (P), the glass veil may have a binder content of 6.0 wt% to 7.0 wt%. Meanwhile, the glass veil may have a machine direction tensile strength of 20 N/5cm to 40 N/5cm, and a moisture content of 0.2 wt% or less.

Due to the use of the resin (P), the impact absorption performance of the fiber-reinforced composite material 100 can be improved. The resin (P) may be any one of a thermoplastic resin or a thermosetting resin.

The fiber-reinforced composite material 100 may be manufactured by a High-Pressure Resin Transfer Molding (HP-RTM) method.

When the fiber-reinforced composite material 100 is manufactured by the HP-RTM (High-Pressure Resin Transfer Molding) method, the resin (P) may be a thermosetting resin, and examples of the thermosetting resin include epoxy resin, phenol resin, urea and one selected from the group consisting of resins, melamine resins, and combinations thereof.

In the HP-RTM method, a non-flexible laminate (1P), at least one woven fabric sheet (2P), and at least one nonwoven fabric sheet (NW) are sequentially laminated in a mold, and then a resin (P) and a curing agent are rapidly mixed. It is a method of manufacturing the fiber-reinforced composite material 100 by hardening after impregnation at high pressure.

The fiber-reinforced composite material 100 may be manufactured using a prepreg. The prepreg is an intermediate material impregnated with resin (P) in the fabric, and the prepreg of the non-bending laminate (1P) is an intermediate material in which the non-bending laminate (1P) is impregnated with the resin (P), and the woven fabric sheet (2P) ) of the prepreg is an intermediate material impregnated with the resin (P) in the woven fabric sheet (2P).

Unlike the method of manufacturing the fiber-reinforced composite material 100 by the HP-RTM method, the method for manufacturing the fiber-reinforced composite material 100 using a prepreg is an NCF sheet (n), an NCF sheet (n+ 1), the NCF sheet (n+2), the intermediate material already impregnated with the resin (P) in the woven fabric sheet (2P) is used.

A method of manufacturing the fiber-reinforced composite material 100 using a prepreg is a prepreg of a non-bending laminate (1P), a prepreg of a woven fabric sheet (2P), and a nonwoven fabric sheet (NW) are sequentially laminated Then, the adhesive resin is injected into the laminate through a composite molding process such as RTM (Resin Transfer Molding), WCM (Wet Compression Molding), PCM (Prepreg Compression Molding), and hot press, so that at least and coating and curing an adhesive resin on one surface.

When the fiber-reinforced composite material 100 is manufactured using a prepreg, the resin P may be a thermoplastic resin or a thermosetting resin. Examples of the thermoplastic resin include one selected from the group consisting of polypropylene (PP) resin, polyethylene terephthalate (PET) resin, polyethylene (PE) resin, polyamide (PA) resin, and combinations thereof.

Example

Four NCF sheets were laminated so that the orientation direction of the continuous carbon fibers of each layer formed an intersection angle of 0°/ +45°/ 90°/ -45° to obtain a non-bend laminate. Subsequently, one twill pattern fabric sheet (TW sheet) and one glass veil (GF veil) are sequentially laminated on the upper and lower portions of the non-bending laminate, respectively, from the bottom to the top GF veil / TW sheet / NCF sheet (0°)/ NCF sheet(+45°)/ NCF sheet(90°)/ NCF sheet(-45°)/ TW sheet/ GF veil were laminated in order to obtain a laminate. In each of the woven fabric sheets (WF sheet), the intersection angle between the weft and the warp was 90°, and the carbon continuous fibers were unidirectionally oriented in the longitudinal direction of the weft and the warp.

After the laminate was placed in a mold, a mixture of an epoxy resin and a curing agent was impregnated under high pressure to obtain a fiber-reinforced composite material according to the embodiment.

comparative example

TW sheet/ NCF sheet (0°)/ NCF sheet (+45°)/ NCF sheet (90°)/ NCF sheet (-45 °)/ A fiber-reinforced composite material according to the comparative example in which the TW sheet was laminated in this order was manufactured.

Experimental example

The surface uniformity was measured using the fiber-reinforced composite material according to the Example and the fiber-reinforced composite material according to the comparative example, and FIG. 3 shows an image of measuring the surface uniformity of the fiber-reinforced composite material according to the Example, An image of measuring the surface uniformity of the fiber-reinforced composite material according to the comparative example is shown.

Table 1 summarizes the surface uniformity measurement results and glossiness (incident angle: reflection angle = 60°: 60°) measurement results.

division amplitude
(μm) Glossiness (60°:60°) Example 2.00 90.2 comparative example 2.33 90.1

Although the embodiments have been described above with reference to the accompanying drawings, the invention is not limited to the above embodiments, but may be manufactured in various different forms by combining the contents disclosed in each embodiment, and is commonly known in the art to which the invention pertains. Those skilled in the art will be able to understand that the invention may be implemented in other specific forms without changing the technical spirit or essential features of the invention. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

1: continuous reinforcing fiber
P: resin
1P: non-bend laminate
2P: Woven fabric sheet
NW: non-woven sheet
100: fiber-reinforced composite material

Claims (10)

a non-bend laminate comprising sheets of non-crimp fabric (NCF), wherein at least one of a top layer and a bottom layer is one of the sheets of NCF fabric;
at least one woven fabric sheet disposed on at least one of the uppermost layer and the lowermost layer of the non-bend laminate and comprising a weft yarn and a warp yarn;
at least one nonwoven fabric sheet disposed on the at least one woven fabric sheet, the nonwoven fabric sheet having irregularly oriented discontinuous fibers entangled; and
resin; including,
The resin is impregnated into the NCF sheets, the at least one woven sheet and the at least one nonwoven sheet,
Each of the NCF sheets, the weft and the warp includes continuous reinforcing fibers oriented in one direction,
The unidirectional orientation direction of the continuous reinforcing fibers of the weft yarn and the unidirectional orientation direction of the continuous reinforcing fibers of the warp yarn cross each other,
The nonwoven sheet is a glass veil,
The glass veil includes long glass fibers and a binder,
The glass veil has a binder content of 6.0 wt% to 7.0 wt%,
The ratio of the refractive index of the nonwoven sheet to the refractive index of the resin is 1:0.9 to 1:1.1,
The weft and warp threads each have a width of 0.5 mm to 20 mm.
Fiber-reinforced composites. According to claim 1,
The woven fabric sheet is a twill fabric sheet
Fiber-reinforced composites. 3. The method of claim 2,
The twill fabric sheet has a twill (twill) pattern
Fiber-reinforced composites. According to claim 1,
The intersection angle between the unidirectional orientation direction of the continuous reinforcing fibers of the weft and the unidirectional orientation direction of the continuous reinforcing fibers of the warp yarn is 30° to 90°
Fiber-reinforced composites. According to claim 1,
The NCF sheets include a first NCF sheet and a second NCF sheet,
The first NCF sheet and the second NCF sheet are stacked in a one-way orientation direction of the continuous reinforcing fibers alternately with each other.
Fiber-reinforced composites. 6. The method of claim 5,
An intersection angle between the unidirectional orientation direction of the continuous reinforcing fibers of the first NCF sheet and the unidirectional orientation direction of the continuous reinforcing fibers of the second NCF sheet is 30° to 90°
Fiber-reinforced composites. delete According to claim 1,
The nonwoven sheet is a glass veil,
The glass veil has a basis weight of 30 g/m ² to 50 g/m ²
Fiber-reinforced composites. According to claim 1,
The nonwoven sheet, the woven fabric sheet, the non-bend laminate, the woven fabric sheet and the nonwoven fabric sheet are sequentially laminated in the order
Fiber-reinforced composites. According to claim 1,
The glass veil is a structure in which the binder is coated on the surface of the long glass fiber.
Fiber-reinforced composites.

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