KR102470704B1 - Sheet - Google Patents

Abstract

This application relates to a sheet, a method for producing the same, and a use thereof. According to the present application, high strength and light weight can be realized, and such a sheet can be applied to a side skirt for a trailer to reduce fuel consumption.

Description

sheet {SHEET}

This application relates to a sheet, a method for producing the same, and a use thereof.

A sheet manufactured by impregnating continuous fibers into a matrix resin can utilize the mechanical properties of the fibers according to the arrangement direction of the fibers.

In general, a sheet is manufactured by including a prepreg formed by impregnating a resin into a fiber sheet having a single direction, or by laminating a plurality of prepregs.

Since the sheet manufactured in this way is excellent in torsion resistance and bending resistance, it is widely used in various fields such as structures for sports and leisure such as golf clubs and structures such as telephone poles.

However, automobile parts that require high strength, such as side skirts for automobiles, seat backs, and bumper back beams, as well as ships and aircraft, increase in weight to improve strength, resulting in high fuel consumption. A problem occurred.

Therefore, there is a demand for a sheet to solve these problems.

An object of the present application is to provide a high-strength and lightweight sheet, a manufacturing method thereof, and a use thereof.

This application relates to a sheet. Hereinafter, the sheet of the present application will be described with reference to the accompanying drawings, and the attached drawings are exemplary, and the sheet of the present application is not limited to the accompanying drawings.

1 shows a sheet according to an embodiment of the present application. As shown in FIG. 1, it includes a core layer (A) containing a self-reinforcing resin and skin layers (B10, B20) positioned on opposite sides of the core layer.

The core layer (A) has a reinforcing material (a1) and a base material (a2) having different melting points. In this specification, the reinforcing material (a1) means a fibrous material oriented in a single direction to increase the strength of the sheet. In addition, in the present specification, the base material (a2) means a material for enclosing the reinforcing material (a1) and imparting adhesive force to the reinforcing material (a1).

The self-reinforcing resin-containing core layer (A) means a core layer in which the reinforcing material (a1) and the base material (a2) are made of the same components. For example, the component may be a resin or a polymer. Since the reinforcing material (a1) and the base material (a2) are made of the same component, interfacial adhesion may be excellent, and thus, a sheet having excellent strength may be provided.

The same components used for the reinforcing material (a1) and the base material (a2) are not particularly limited. In one example, the reinforcing material (a1) and the base material (a2) may include an olefin-based resin. Specifically, the reinforcing material (a1) and the base material (a2) may include propylene resin.

The melting points of the reinforcing material (a1) and the base material (a2) may be different. Specifically, the melting point of the base material (a2) may be lower than the melting point of the reinforcing material (a1). Since the base material (a2) has a lower melting point than the reinforcing material (a1), it can be melted earlier than the reinforcing material (a1) in a bonding step to be described later and have adhesive strength, and the reinforcing material (a1) can be fixed.

In one example, the melting point of the base material (a2) may be 120°C to 160°C. Specifically, the melting point of the base material (a2) may be 125°C to 155°C, 130°C to 150°C, or 135°C to 145°C.

In addition, the melting point of the reinforcing material (a1) is not particularly limited as long as it is higher than the melting point of the base material (a2). For example, the melting point of the reinforcing material (a1) may have a lower limit of 160°C or more, 165°C or more, or 170°C or more, and an upper limit of 200°C or less, 190°C or less, or 180°C or less. Since the core layer (A) includes the reinforcing material (a1) having a melting point within the above-described range, it is not melted during sheet manufacturing and can maintain its shape as it is.

In one example, the core layer (A) may include the reinforcing material (a1) in excess compared to the base material (a2). Specifically, the core layer (A) may include 50 wt% to 80 wt% of the reinforcing material (a1) and 20 wt% to 50 wt% of the base material (a2). More specifically, the content of the reinforcing material (a1) included in the core layer (A) may be 60% to 70% by weight. In addition, the content of the base material (a2) included in the core layer (A) may be 30% to 40% by weight. The core layer (A) may exhibit excellent strength by including the reinforcing material (a1) and the base material (a2) in an amount within the above range.

2 is a view shown to explain the manufacturing method of the self-reinforcing resin-containing core layer (A) according to an embodiment of the present application. As shown in FIG. 2, the base material (a2') is melted in a molten state by a co-extrusion method in which the reinforcing material (a1) and the base material (a2') are melted at a temperature equal to or higher than their respective melting points and then extruded simultaneously. It can be formed to surround the outside of a1). Thereafter, after stretching the base material (a2') surrounding the outside of the reinforcing material (a1) in a molten state, as shown in FIG. can have a shape. In this specification, "base material (a2')" means a material corresponding to the precursor of the base material (a2), and specifically, in the laminating step to be described later, the base material (a2) of the core layer (A) is formed It may be the material previously surrounding the reinforcing material (a1).

In one example, after weaving the base material (a2′) surrounding the outside of two or more reinforcing materials (a1) using a loom commercially available in the art, the base material surrounding the outside of the two or more reinforcing materials (a1) ( By laminating the skin layers B10 and B20 oppositely on both sides of a2′), as shown in FIG. 3B, the core layer A in the form of a woven fabric can be formed.

In another example, the base material (a2') surrounding the outside of the two or more reinforcing materials (a1) is not woven, and the base material (a2') surrounding the outside of the two or more reinforcing materials (a1) is aligned in the same direction. After that, the skin layers (B10, B20) are laminated facing each other on both sides, so as shown in FIG. 3C, the core layer (A) in which the base material (a2) surrounding the outside of the reinforcing material (a1) is formed in one direction. ) can be formed.

For example, the woven fabric may include plain weave, twill weave, or satin weave. The plain weave refers to a structure in which weft and warp yarns are alternated one by one. In addition, the twill weave refers to a structure in which two or more weft or warp yarns are skipped and crossed to form a pattern in an oblique direction. In addition, satin weave refers to a structure in which a lot of warp or weft yarns appear on the surface of the fabric. Since the core layer exhibits the above-described woven fabric form, the impact resistance of the sheet may be excellent.

The skin layers B10 and B20 have glass fiber reinforcing materials b11 and b21 and base materials b12 and b22.

In one example, the glass fiber reinforcing materials b11 and b21 may be continuous glass fibers. The continuous glass fibers refer to continuous glass fibers that are not physically cut. For example, the continuous glass fibers may be classified into skeletons, which are individual units, according to physical continuity or interruption. The glass fiber reinforcing materials (b11, b21) extend from the first edge of the skin layers (B10, B20) impregnated with the glass fiber reinforcing materials (b11, b21) in a state of physical continuity and face the first edge. It may contact the second edge. Since the glass fiber reinforcing materials b11 and b21 are used in the form of continuous glass fibers, orientation can be formed and maintained better than in the case of using non-continuous fibers cut to have a predetermined length, such as short fibers.

Also, one skin layer (B10, B20) may include two or more glass fiber reinforcing materials (b11, b21). In addition, the two or more glass fiber reinforcements b11 and b21 included in one layer may be aligned within the skin layers B10 and B20. The glass fiber reinforcing materials b11 and b21 may be, for example, a kind of fiber skeleton formed by stacking or twisting single-stranded fibers such as glass fibers. The base material (b12, b22) includes an olefin-based resin, and the melting point of the base material (b12, b22) may be 120°C to 150°C. Specifically, the melting point of the base material (b12, b22) may be 125 °C to 148 °C, 130 °C to 145 °C, or 135 °C to 143 °C. The base material (b12, b22) includes an olefin-based resin having a melting point in the above range, so that the same component having the same melting point as that of the base material (a2) of the core layer (A) can be formed, and thereby, When manufacturing the sheet, adhesion at the interface between the core layer (A) and the skin layers (B10 and B20) may be excellent.

Accordingly, the base material (a1) and the base materials (b12, b22) may be fused to each other. Since the base material (a1) and the base materials (b12, b22) are fused to each other, the adhesive strength at the interface between the core layer (A) and the skin layers (B10, B20) is increased without using a separate adhesive. can be excellent

The skin layers (B10, B20) include a first skin layer (B1) and a second skin layer (B2) in which the alignment directions of the glass fiber reinforcing materials are different from each other.

In one example, the stacking order of the skin layers B10 and B20 is not particularly limited. For example, the first skin layer (B1) is formed closer to the core layer (A) than the second skin layer (B2), or the second skin layer (B2) is formed to be adjacent to the first skin layer (B1). ), it may be formed to be adjacent to the core layer (A).

In one example, the first skin layer (B1) includes glass fiber reinforcing materials (b11, b21) aligned in a first direction, and the second skin layer (B2) includes glass fiber reinforcing materials aligned in a second direction. (b12, b22) may be included.

Specifically, the fact that the alignment directions are different from each other means that the glass fiber reinforcing materials of each of the first skin layer (B1) and the second skin layer (B2) can be disposed in a single direction, and the glass fiber reinforcement of the first skin layer (B1) This may mean that alignment directions of the fiber reinforcement and the glass fiber reinforcement of the second skin layer (B2) cross each other.

The alignment directions of the glass fiber reinforcing material (b11) of the first skin layer (B1) and the glass fiber reinforcing material (b21) of the second skin layer (B2) are not particularly limited as long as they cross each other. In one example, the first direction and the second direction may be orthogonal. In this specification, "orthogonal" means that the angle formed by the first direction and the second direction is 90 degrees, but in practice, an angle allowing an error of ± 10, ± 5, ± 3, ± 1 or ± 0.1 can mean Since the alignment directions of the glass fiber reinforcing materials b11 and b21 included in each of the first skin layer B1 and the second skin layer B2 are orthogonal to each other, it may be advantageous to secure resistance to external force from the side surface.

In addition, each of the first skin layer (B1) and the second skin layer (B2) may be composed of one or two layers. The skin layers (B10, B20) including the first skin layer (B1) and the second skin layer (B2) composed of the above-mentioned number of layers are 2 to 4 layers on opposite sides of the core layer (A), respectively. can be formed Even if the skin layers (B10, B20) including the first skin layer (B1) and the second skin layer (B2) having the above-mentioned number of layers are included in the above-mentioned number of layers, the sheet is reduced in weight by satisfying the low density described later. can make it

In one example, the skin layers B10 and B20 include 40 wt% to 70 wt% of the glass fiber reinforcing materials b11 and b21, and 30 wt% to 60 wt% of the matrix materials b12 and b22. % can be included. Specifically, the skin layers B10 and B20 may include the glass fiber reinforcing materials b11 and b21 in excess compared to the base materials b12 and b22. More specifically, the lower limit of the content of the glass fiber reinforcing materials (b11, b21) may be 50 wt% or more or 55 wt% or more, and the upper limit may be 65 wt% or less. In addition, the lower limit of the content of the base material (b12, b22) included in the skin layers (B10, B20) may be 35% by weight or more, and the upper limit may be less than 50% by weight or 45% by weight or less. The skin layers B10 and B20 include the glass fiber reinforcing materials b11 and b21 and the matrix materials b12 and b22 in an amount within the above range, so that high strength and light weight may be realized.

In one example, the sheet may have a density of 0.5 g/cm ³ to 1.5 g/cm ³ , specifically, 0.6 g/cm ³ to 1.4 g/cm ³ , 0.7 g/cm ³ to 1.3 g/cm ³ , 0.8 g/cm ³ to 1.2 g/cm ³ or 0.9 g/cm ³ to 1.1 g/cm ³ . The sheet may be reduced in weight by having the aforementioned density.

This application also relates to a method for manufacturing a sheet. The method for manufacturing the sheet relates to the method for manufacturing the above-described sheet, and the details described in the sheet may be equally applied to specific details of the sheet to be described later.

Exemplary method of manufacturing a sheet of the present application includes glass fiber reinforcing materials (b11, b21) on both sides of a self-reinforcing resin-containing core layer (A) including a reinforcing material (a1) and a base material (a2') having different melting points, and and laminating the skin layers B10 and B20 having the base materials b12 and b22 to face each other.

The self-reinforcing resin-containing core layer (A) may be used by preparing a product obtained by co-extruding a reinforcing material (a1) and a base material (a2') having different melting points and stretching in one direction. A self-reinforced polypropylene resin (Curv, Propex Fabrics, Germany) may be used as the core layer (A) containing a self-reinforcing resin according to an embodiment.

Specifically, as shown in FIG. 2, in the co-extrusion, the reinforcing material (a1) and the base material (a2') are melted at a temperature equal to or higher than their respective melting points, and then simultaneously extruded to form the base material (a2') in a molten state. may be formed to surround the outside of the reinforcing member (a1). Thereafter, after stretching the base material (a2') surrounding the outer side of the reinforcing material (a1) in a molten state, as shown in FIG. can

Then, in one example, after weaving the base material (a2') surrounding the outside of the two or more reinforcing materials (a1) using a loom commercially available in the art, the base material surrounding the outside of the two or more reinforcing materials (a1). The skin layers (B10, B20) are laminated on both sides of the material (a2') to face each other to produce a self-reinforcing resin-containing core layer (A) in the form of a woven material shown in FIG. 3B.

In another example, after aligning two or more base materials (a2') surrounding the outer axis of the reinforcing material (a1) in the same direction, the base material (a2') surrounding the outer axis of the two or more reinforcing materials (a1) By laminating the skin layers (B10, B20) on both sides, the base material (a2) surrounding the outside of the reinforcing material (a1) shown in FIG. 3c is formed in one direction. have.

At this time, by co-extruding the reinforcing material (a1) and the base material (a2'), the base material (a2') surrounds the outer axis of the reinforcing material (a1), and the base material surrounding the outer axis of the two or more reinforcing materials (a1). When the skin layers (B10, B20) are laminated on both sides of the material (a2') to face each other, the base material (a2') and the base material (b2') included in the skin layers (B10, B20) are at a temperature described later. Since it is melted in, it is possible to manufacture a sheet having a sandwich structure.

The manufacturing method of the sheet may further include forming skin layers B10 and B20. 4 is a diagram shown to explain a step of forming a skin layer according to an embodiment of the present application. As shown in FIG. 4 , the step of forming the skin layer may be performed by impregnating the matrix materials b12 and b22 into the glass fiber reinforcing materials b11 and b21.

Specifically, the glass fiber reinforcing materials (b11, b21) having a diameter of 15 μm to 20 μm unwound from the creel equipment in which the glass fiber reinforcing materials (b11, b21) are wound are bundled with 3500 to 4500 strands by a bundling agent to obtain 1 One roll having a width of 5 mm to 5 mm can be formed (see numeral 41 in Fig. 4). Thereafter, the glass fiber reinforcing materials b11 and b21 may be spread at 5 mm to 15 mm per roll through a spreading roll (see numeral 42 in FIG. 4). Thereafter, the base materials (b12, b22) are supplied to the impregnation die so that the glass fiber reinforcing materials (b11, b21) are formed at a temperature of 200° C. to 240° C. and within the melt viscosity of the base materials (b12, b22). It can be impregnated with the ash (b12, b22) (see numeral 43 in FIG. 4). In this way, the step of forming the skin layer may be performed. In step 43 of FIG. 4 , the glass fiber reinforcing materials b11 and b21 passed through the spreading roll may be specifically spread at 7 mm to 13 mm or 9 mm to 11 mm per roll. When the glass fiber reinforcing materials b11 and b21 passed through the spreading rolls are spread within the above range, it may be easy to impregnate the matrix materials b12 and b22 between the glass fiber reinforcing materials b11 and b21. In addition, the impregnation temperature may be specifically, 210 °C to 230 °C or 220 °C to 230 °C. When the impregnation temperature satisfies the aforementioned range, the flowability of the base materials b12 and b22 is high and the viscosity is low, so that the base materials b12 and b22 are impregnated between the glass fiber reinforcing materials b11 and b21. it can be easy

In one example, the forming of the skin layers B10 and B20 may further include calendaring and cutting. Specifically, the calendering may be performed by compressing and cooling the base material (b12, b22) impregnated inside the glass fiber reinforcing material (b11, b21) through a calender (see numeral 44 in FIG. 4). The cutting may be performed by cutting the calendered skin layers B10 and B20 into sizes according to the intended use (see numeral 45 in FIG. 4).

Figure 5 is a view shown to explain the step of laminating according to an embodiment of the present application. As shown in FIG. 5, the laminating step is to laminate skin layers (B10, B20) having glass fiber reinforcing materials (b11, b21) and base materials (b12, b22) on both sides of the core layer (A). carry out Specifically, the lamination may be performed using a hot press, and in one embodiment, it may be performed using a double belt press or the like.

In one example, the laminating step may be performed at 140° C. to 160° C., specifically, 143° C. to 158° C. in consideration of melting points of the core layer (A) and the skin layers (B10 and B20), respectively. °C, 145 °C to 155 °C or 148 °C to 152 °C. By performing the laminating step in the above-described temperature range, the core layer (A) and the skin layers (B10, B20) can be laminated with excellent adhesive strength.

This application also relates to the use of the sheet. The sheet of the present application can exhibit high strength and light weight. Such a seat can be applied to side skirts for trailers, for example.

The seat of the present application can realize high strength and light weight, and such a seat can be applied to a side skirt for a trailer to reduce fuel consumption.

1 shows a sheet according to an embodiment of the present application.
2 is a diagram shown to explain a step of forming a core layer according to an embodiment of the present application.
3A is a view showing a base material (a2') surrounding the outer axis of a reinforcing material (a1) formed after co-extrusion according to an embodiment of the present application.
Figure 3b shows a core layer (A) in the form of a woven material according to an embodiment of the present application.
3C shows a cross section of a core layer (A) in which a base material (a2) surrounding the outer axis of a reinforcing material (a1) is formed in one direction according to another embodiment of the present application.
4 is a diagram shown to explain a step of forming a skin layer according to an embodiment of the present application.
Figure 5 is a view shown to explain the step of laminating according to an embodiment of the present application.
6 is a view showing a sheet prepared in Comparative Example 1.
7 is a view showing a sheet prepared in Comparative Example 2.
8 is a view showing a sheet prepared in Comparative Example 3.

Although the present application is specifically described through the following examples, the scope of the present application is not limited by the following examples.

Example 1

manufacture of sheets

A sheet was prepared by laminating opposing skin layers (B10, B20) on both sides of the self-reinforcing resin-containing core layer (A).

Specifically, as the self-reinforcing resin-containing core layer (A), a reinforcing material (a1) having a melting point of 170 ° C and made of polypropylene resin and a base material (a2) made of polypropylene resin and having a melting point of 130 ° C. A self-reinforcing polypropylene resin (Curv, Propex Fabrics, Germany) was prepared.

Then, as shown in FIG. 4, the glass fiber reinforcing materials (b1, SE4849, OCV) were unwound from the creel equipment (LG Hausys) on which the glass fiber reinforcing materials (b1, SE4849, OCV) were wound (41). Thereafter, the glass fiber reinforcing materials (b11, b21) were spread at 10 mm per roll through a spreading roll (LG Hausys) (42). Thereafter, the glass fiber reinforcing materials (b11, b21) passed through the spreading rolls were moved to an impregnation die (LG Hausys). Subsequently, as the base material (b12, b22), a polypropylene resin having a melting point of 130 ° C. is prepared, supplied to the impregnation die, and then the glass fiber reinforcing materials (b11, b21) are prepared at a temperature of 150 ° C. It was impregnated with ash (b12, b22) (43). Thereafter, the reinforcing materials (b11, b21) impregnated into the base materials (b12, b22) are pressed through a calender with a distance of 0.3 mm between the upper and lower rolls and a temperature of the upper and lower rolls of 60°C. And after cooling (44), by cutting into 8000 mm in width and 1000 mm in length (45), the first skin layer (B1) having a thickness of 0.25 mm and the glass fiber reinforcements (b11, b21) facing in the first direction, and A second skin layer (B2) in which the glass fiber reinforcing materials (b11, b21) were directed in the second direction was prepared, respectively.

Subsequently, as shown in FIG. 5, the skin layers (B10, B20) in which the first skin layer (B1) and the second skin layer (B2) are laminated are placed on both sides of the self-reinforcing resin-containing core layer (A) prepared above. After positioning each facing each other, by laminating with a double belt press (LG Hausys) at a temperature of 150 ° C., a sheet having a thickness of 3.5 mm was prepared.

Comparative Example 1

manufacture of sheets

As shown in FIG. 6, the first skin layer and the second skin layer are alternately laminated without forming a core layer, except that the total number of layers of the first skin layer and the second skin layer is 11. A sheet having a width of 8000 mm, a length of 1000 mm and a thickness of 3.5 mm was prepared in the same manner as in Example 1.

Comparative Example 2

manufacture of sheets

As shown in FIG. 7, a core layer made of a glass fiber reinforcing material (SE4849, OCV) is prepared, and the first skin layer and the second skin layer are alternately laminated so that the total number of layers of the first skin layer and the second skin layer is A sheet having a width of 8000 mm, a length of 1000 mm, and a thickness of 3.5 mm was prepared in the same manner as in Example 1, except that it was formed in three layers.

Comparative Example 3

manufacture of sheets

As shown in FIG. 8, a core layer made of a glass fiber reinforcing material (SE4849, OCV) is prepared, and reinforcing materials impregnated in the base material included in each of the first skin layer and the second skin layer are woven in a plain weave to form a skin layer. A sheet having a width of 8000 mm, a length of 1000 mm, and a thickness of 3.5 mm was prepared in the same manner as in Example 1, except that it was prepared.

experimental example. Property evaluation

Using an underwater hydrometer (XP504V, Mettle Toledo), the ASTM D792 measurement method was used to measure the density and weight of the sheets prepared in Examples and Comparative Examples, respectively, and the results are shown in Table 1 below.

Density (g/cm ³ ) Weight (kg) Example 1 1.05 29.4 Comparative Example 1 1.41 39.5 Comparative Example 2 1.24 34.7 Comparative Example 3 1.53 42.8

As shown in Table 1, it was confirmed that the sheet prepared in Example 1 had lower density and weight than the sheets prepared in Comparative Examples 1 to 3 having the same volume.

A: core layer
a1: stiffener
a2, a2': base material
B10, B20: skin layer
B1: first skin layer
B2: second skin layer
b11, b21: glass fiber reinforcement
b12, b22: base material
41: In the method for manufacturing a sheet according to an embodiment of the present application, the process of unwinding the glass fiber reinforcing material from the creel
42: In the sheet manufacturing method according to an embodiment of the present application, the process of spreading the glass fiber reinforcing material through a spreading roll
43: Process of impregnating the glass fiber reinforcing material and the base material in the sheet manufacturing method according to an embodiment of the present application
44: process of calendering the base material impregnated inside the glass fiber reinforcing material in the sheet manufacturing method according to an embodiment of the present application
45: process of cutting the skin layer in the manufacturing method of the sheet according to an embodiment of the present application

Claims (12)

a core layer (A) containing a self-reinforcing resin having a reinforcing material (a1) and a base material (a2); and
And skin layers (B10, B20) respectively formed on opposite sides of the core layer (A),
The skin layers (B10, B20) each include a first skin layer (B1) and a second skin layer (B2) in which the alignment directions of the glass fiber reinforcing materials are different from each other,
The first skin layer (B1) has a glass fiber reinforcing material (b11) and a base material (b12),
The second skin layer (B2) has a glass fiber reinforcing material (b21) and a base material (b22),
The reinforcing material (a1) and the base material (a2, b12, b22) are propylene resin,
The base material (a2) has a lower melting point than the reinforcing material (a1),
A sheet in which the base material (a2) and the base materials (b12, b22) are fused to each other. delete The sheet according to claim 1, wherein the base material (a2) has a melting point in the range of 120°C to 160°C. The sheet according to claim 1, wherein the glass fiber reinforcing materials (b11, b21) are continuous glass fibers. The sheet according to claim 3, wherein the base material (b12, b22) has a melting point in the range of 120°C to 160°C. The sheet according to claim 5, wherein the base material (a2) has the same melting point as the base materials (b12, b22). The method of claim 1, wherein the first skin layer (B1) includes glass fiber reinforcements (b11) aligned in a first direction, and the second skin layer (B2) includes glass fiber reinforcements (b11) aligned in a second direction. b21), wherein the first direction and the second direction are orthogonal to each other. The method of claim 1, wherein the skin layers (B10, B20) contain 40 wt% to 70 wt% and 30 wt% to 60 wt% of the glass fiber reinforcing materials (b11, b21) and the matrix materials (b12, b22), respectively. A sheet containing as . The sheet according to claim 1 , having a density of 0.5 g/cm ³ to 1.5 g/cm ³ . Laminating the skin layers (B10, B20) facing each other on both sides of a core layer (A) containing a self-reinforcing resin having a reinforcing material (a1) and a base material (a2') having a lower melting point than the reinforcing material (a1). including,
The skin layers (B10, B20) each include a first skin layer (B1) and a second skin layer (B2) in which the alignment directions of the glass fiber reinforcing materials are different from each other,
The skin layer (B1) has a glass fiber reinforcing material (b11) and a base material (b12),
The skin layer (B2) has a glass fiber reinforcing material (b21) and a base material (b22),
The base material (a2') is formed of the base material (a2) after laminating,
The reinforcing material (a1) and the base material (a2, b12, b22) are propylene resin,
The method of manufacturing a sheet in which the base material (a2) is fused to each other with the base materials (b12, b22). 11. The method of claim 10, wherein the laminating is performed at 140 °C to 160 °C. A side skirt for a trailer comprising the seat of claim 1.

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