KR20200134793A - Sandwich board - Google Patents

Abstract

The present invention provides a sandwich board comprising a center layer and a surface layer, wherein the center layer is foam of a first thermoplastic resin, and the surface layer is a porous fiber-reinforced composite sheet comprising a reinforcing fiber and a binder resin of a second thermoplastic resin. The sandwich board according to the present invention achieves weight reduction, excellent strength, and excellent sound-absorbing properties at the same time.

Description

Sandwich board {SANDWICH BOARD}

The present invention relates to a sandwich board.

Using a conventional nonwoven fabric-based porous composite material, weight reduction and sound-absorbing performance are improved compared to a material manufactured by conventional injection molding. However, the non-woven fabric-based porous composite material required a rapid weight increase in order to manufacture a thicker part of a certain level or more, thereby reducing productivity.

There is a case where a thermosetting resin is attached to such a nonwoven fabric-based porous composite material using an adhesive.

It is an object of the present invention to provide a sandwich board with light weight, excellent strength, and excellent sound-absorbing properties.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention that are not mentioned can be understood by the following description, and will be more clearly understood by examples of the present invention. In addition, it will be easily understood that the objects and advantages of the present invention can be realized by the means shown in the claims and combinations thereof.

In one embodiment of the present invention, the center layer; And a surface layer, wherein the center layer is a foam of a first thermoplastic resin, and the surface layer is a porous fiber-reinforced composite sheet comprising a reinforcing fiber and a binder resin of a second thermoplastic resin.

The sandwich board according to the present invention achieves weight reduction, excellent strength and excellent sound-absorbing properties at the same time.

In addition to the above-described effects, specific effects of the present invention will be described together while describing specific details for carrying out the present invention.

1 shows a cross section of a sandwich board according to an embodiment of the present invention.

The above-described objects, features, and advantages will be described later in detail (with reference to the attached drawings), and accordingly, a person of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar elements.

Hereinafter, it means that an arbitrary component is disposed on the "top (or lower)" of the component or the "top (or lower)" of the component, the arbitrary component is arranged in contact with the top (or bottom) of the component. In addition, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

In addition, when a component is described as being "connected", "coupled" or "connected" to another component, the components may be directly connected or connected to each other, but other components are "interposed" between each component. It is to be understood that "or, each component may be "connected", "coupled" or "connected" through other components.

Hereinafter, an induction heating and wireless power transmission apparatus according to some embodiments of the present invention will be described.

In one embodiment of the present invention, the center layer; And a surface layer, wherein the center layer is a foam of a first thermoplastic resin, and the surface layer is a porous fiber-reinforced composite sheet comprising a reinforcing fiber and a binder resin of a second thermoplastic resin.

The sandwich board 100 can be molded by secondary processing because both the material of the intermediate layer 10 and the binder resin of the surface layer 20 are made of thermoplastic resin. That is, additional molding by heat is possible, and, for example, the sandwich board 100 having a panel shape may be given a shape by secondary heat molding. The shape can be two-dimensional and three-dimensional, and partial shapes are also possible.

Conventionally, there is a case where a thermosetting resin such as polyurethane is applied to the fiber-reinforced composite material, but in the case of the thermosetting resin, there is a problem that it is difficult to formability and secondary processing. Since the sandwich board 100 uses a thermoplastic resin, this problem is solved.

In addition, in the case of the thermosetting resin, a separate adhesive must be used for bonding the intermediate layer and the surface layer, but if a thermoplastic resin is used, since thermal fusion is possible, an adhesive may not be used separately. Therefore, since the sandwich board 100 does not use a separate chemical adhesive, there is an advantage in that VOC can be reduced.

1 shows a cross section of a sandwich board 100 according to an embodiment of the present invention.

The sandwich board 100 includes a center layer 10 and a surface layer 20. In FIG. 1, the sandwich board 100 has a structure in which surface layers 20 are stacked on both sides of a center layer 10.

The center layer 10 is a foam of a first thermoplastic resin. Alternatively, the center layer 10 may be formed of a first thermoplastic resin foam.

The first thermoplastic resin may be a thermoplastic resin capable of forming a foam, for example, polyester, polyethylene terephthalate, polypropylene (PP), polyethylene (PE), acrylic butadiene styrene (ABS), polycarbonate (PC), nylon, polyvinyl chloride (PVC), polystyrene (PS), polyurethane (PU), polymethylmethacrylate (PMMA), polylactic acid (PLA), Teflon (polytetrafluoroethylene), and these It may include at least one selected from the group consisting of a combination of, but is not limited thereto.

Specifically, the foam may be prepared by mixing the first thermoplastic resin with an additive including a plasticizer, a flame retardant, a stabilizer, a nucleating agent, or a combination thereof, and foaming and extruding. The foam may be manufactured by controlling to have a desired thickness and weight.

Since the sandwich board 100 includes a foam of a thermoplastic resin as the center layer 10, the weight is reduced compared to the case where only the porous fiber-reinforced composite sheet forming the surface layer 20 has the same overall thickness. Accordingly, while meeting the recent demand for weight reduction of automobile parts, the sandwich board 100 can maintain rigidity by the surface layer 20. That is, the sandwich board 100 can achieve weight reduction and rigidity maintenance effect at the same time.

When the sandwich board 100 is applied to a component having a thickness of, for example, 5 mm or more, it is useful because it can effectively reduce weight while maintaining rigidity. For example, in automobile parts, it can be applied in various ways, from interior parts such as headliners, luggage boards, and package trays to exterior parts such as underbody covers.

In one embodiment, the thickness of the sandwich board 100 may be 5 mm to 100 mm, specifically 5 mm to 10 mm. The sandwich board 100 having the above thickness may have a relatively thick thickness, but may achieve weight reduction and maintain excellent rigidity.

In one embodiment, the sandwich board 100 may be molded to change its thickness. That is, the thickness of the sandwich board 100 may be different.

When the sandwich board 100 is formed, the heating temperature and pressure of the hot press molding may be partially changed to have different thicknesses. The sandwich board 100 can be partially manufactured to have different thicknesses because both the intermediate layer 10 and the surface layer 20 contain a thermoplastic resin, and since additional molding is possible, the thickness can be changed by additional molding. have.

As the thickness decreases, the density increases and the porosity may decrease. Therefore, the sandwich board 100 may have different density and porosity partially.

For example, the sandwich board 100 may be made thinner by heat press molding only on the edge portion by additional molding. Specifically, an area within a distance of 1 cm from the edge of the sandwich board 100 may have a thickness of 5 mm to 10 mm, and the remaining inner area may have a thickness of 15 mm to 30 mm.

The surface layer 20 may be a porous fiber-reinforced composite sheet.

The porous fiber-reinforced composite sheet includes reinforcing fibers and a binder resin for binding the reinforcing fibers. In one embodiment, the porous fiber-reinforced composite sheet may be one in which the reinforcing fibers are bound by the binder resin to form an irregular network structure including pores.

The reinforcing fiber may include at least one selected from the group consisting of aramid fiber, carbon fiber, carbon nanotube, boron fiber, metal fiber, and combinations thereof.

In one embodiment, the porous fiber-reinforced composite sheet may be a nonwoven fabric. In the case of a fabric, directionality is given to physical properties depending on the weaving direction, but if the porous fiber-reinforced composite sheet is formed of a nonwoven fabric, directionality may not be imparted, so it is suitable to impart a shape to the sandwich board 100 by additional molding. Do.

In addition, when the porous fiber-reinforced composite sheet is a non-woven fabric, it is advantageous for diagonal molding. That is, it is excellent in formability in the diagonal direction.

In addition, when the porous fiber-reinforced composite sheet is a non-woven fabric, it is light and can implement excellent strength, so it is suitable for use with the foam of the intermediate layer 10. In this aspect, the reinforcing fibers may be glass fibers.

In addition, when the porous fiber-reinforced composite sheet is a non-woven fabric, excellent sound-absorbing performance may be imparted. That is, while maintaining the pores of the nonwoven fabric in the surface layer 20 and at the same time maintaining the pores of the foam in the intermediate layer 10, the sound-absorbing performance required for the intended application may be realized.

In one embodiment, the porosity of the surface layer 20 may be 50 to 99 vol%, specifically, 70 to 95 vol%, and the porosity of the intermediate layer 10 is 80 to 99 vol%, specifically, It may be 90 to 98% by volume. By forming the surface layer 20 and the intermediate layer 10 to have a porosity in the above range, the sandwich board 100 can implement a relatively low weight, excellent strength, and excellent sound absorption properties.

The porous fiber-reinforced composite sheet is preferable in terms of strength implementation when it has a low weight and has a small weight deviation. The method of manufacturing the porous fiber-reinforced composite sheet with a nonwoven fabric having a small weight variation may be, for example, a wet papermaking method.

That is, the porous fiber-reinforced composite sheet manufactured by the wet papermaking method is applied to the foam of the intermediate layer 10 to effectively improve strength. As a result, it is possible to maintain high strength while reducing the weight of the sandwich board 100.

The binder resin may be a thermoplastic resin, and may be independently selected from a thermoplastic resin forming the foam of the center layer 10. For convenience, the thermoplastic resin forming the foam of the center layer 10 is referred to as a first thermoplastic resin, and the binder resin is referred to as a second thermoplastic resin.

The second thermoplastic resin is, for example, polyester, polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), acrylic butadiene styrene (ABS), polycarbonate (PC), nylon (Nylon), At least one selected from the group consisting of polyvinyl chloride (PVC), polystyrene (PS), polyurethane (PU), polymethyl methacrylate (PMMA), polylactic acid (PLA), Teflon (polytetrafluoroethylene), and combinations thereof It may include.

In one embodiment, the second thermoplastic resin may be a thermoplastic resin suitable for a wet papermaking method.

In one embodiment, the thermoplastic resin may be polypropylene or polyethylene terephthalate (PET).

In one embodiment, the thickness ratio of the surface layer 20 to the center layer 10 may be 1: 1.5 to 9, and specifically, 1: 1.5 to 4. The sandwich board 100 in which the surface layer 20 and the center layer 10 have the thickness ratio may implement a relatively low weight, excellent strength, and excellent sound-absorbing properties.

In one embodiment, the basis weight ratio of the surface layer 20 to the center layer 10 may be 1: 1.5 to 9, specifically, 1: 1.5 to 5. The sandwich board 100 in which the surface layer 20 and the center layer 10 have the basis weight ratio may realize relatively low weight, excellent strength, and excellent sound absorption characteristics.

The sandwich board 100 is prepared by first preparing two sheets of the intermediate layer 10 and the surface layer 20, placing the intermediate layer 10 between the two surface layers 20, and then bonding them by press molding by applying heat. I can. Heat may be applied to melt the first thermoplastic resin and/or the second thermoplastic resin.

Hereinafter, examples and comparative examples of the present invention will be described. The following examples are only examples of the present invention, and the present invention is not limited to the following examples.

(Example)

Example 1

First, the polyester core portion having a melting point of 260°C and the polyester sheath portion having a melting point of 160°C have a weight ratio of 50:50, the length is 12 mm, and the diameter of the cross section perpendicular to the length direction is 4 denier (about 20 Μm) bicomponent polymer fibers were prepared.

Subsequently, a glass fiber having a length of 13 mm, a diameter of a cross section perpendicular to the length direction of 13 μm, and a melting point of 250° C. was prepared as a reinforcing fiber.

Based on 100 parts by weight of the reinforcing fibers, 40 parts by weight of the two-component polymer fibers were blended to prepare a wet paper nonwoven fabric.

The wet paper nonwoven sheet had a basis weight of 160 g/m 2 and a thickness of 2 mm.

The wet papermaking nonwoven fabric thus prepared was laminated on both surfaces of a polyethylene terephthalate foam having a basis weight of 250 g/m ² and a thickness of 5 mm, and then pressed at 200° C. with a pressure of 5 bar to prepare a sandwich composite material having a final thickness of 5 mm.

Comparative Example 1

After applying a polyurethane adhesive as an intermediate layer on both surfaces of a flexible polyurethane foam having a thickness of 5 mm and a basis weight of 250 g/m ² , the wet paper nonwoven fabric prepared as in Example 1 was laminated, and then at 200°C of 5 bar. By pressing with pressure, a sandwich composite material having a final thickness of 5 mm was prepared.

Comparative Example 2

A sandwich composite material was prepared in the same manner as in Example 1, except that the thickness of 1.8 mm and the surface layer of the polypropylene sheet having the same 160 g/m ² were used.

Comparative Example 3

After stacking three sheets of 190 g/m ² nonwoven fabric prepared in the same manner as the wet paper nonwoven fabric in Example 1, a composite material having a final thickness of 5 mm was prepared by pressing at 200°C with a pressure of 5 bar.

evaluation

Experimental Example 1

For the sandwich board and composite plate material prepared in Example 1 and Comparative Examples 1, 2, and 3, the physical properties shown in Table 1 were measured and described.

division Porosity (%) Thickness(mm) Basis weight (g/m ² ) Example 1 Surface layer 90 2 320 Middle floor 94 3 250 ratio - Surface layer: Intermediate layer = 1: 1.5 Surface layer: Intermediate layer=
1: 1.6 Comparative Example 1 Surface layer 90 2 160 Middle floor
(Including adhesive) 94 3 230 ratio - Surface layer: Intermediate layer = 1: 1.5 Surface layer: Intermediate layer=
1: 1.6 Comparative Example 2 Surface layer 0 2 160 Middle floor 94 3 250 ratio - Surface layer: Intermediate layer = 1: 1.5 Surface layer: Intermediate layer=
1: 1.6 Comparative Example 3 Middle floor 93 5 570

The porosity (%) is expressed as the ratio of the volume of pores to the apparent volume of the material and was calculated using the following equation.

Porosity (%) = SS ₁ / S (S: density of the material, S ₁ : apparent density, g/cm ³ )

Experimental Example 2

The basis weight was measured for the sandwich board and composite plate prepared in Example 1 and Comparative Examples 1, 2, and 3, and are shown in Table 2.

The basis weight was calculated by dividing the area after taking a specimen of 100 mm in width and length from a sandwich board and a composite plate, measuring the weight with a general scale.

Experimental Example 3

The strength of the sandwich board and composite material sheet prepared in Example 1 and Comparative Examples 1, 2, and 3 were evaluated as follows, and are shown in Table 2.

Flexural strength was measured according to ASTM d 790 standard after taking specimens of 150 mm in width and 50 mm in length from sandwich boards and composite plates. The test equipment was measured using Instron's 5569A model.

Experimental Example 4

The sound-absorbing performance was evaluated as follows for the sandwich boards and composite plate materials prepared in Example 1 and Comparative Examples 1, 2, and 3, and shown in Table 2.

The average sound absorption coefficient was measured by the KS 2816-2 standard after sampling a specimen with a diameter of 30 mm, and was measured using an impedance tube manufactured by Cyon.

division Basis weight (g/m ² ) Flexural strength (N) Average sound absorption coefficient Example 1 570 18.8 0.13 Comparative Example 1 570 16.3 0.12 Comparative Example 2 570 14.0 0.04 Comparative Example 3 570 15.1 0.16

As described above with reference to the drawings illustrated for the present invention, the present invention is not limited by the embodiments and drawings disclosed in the present specification, and various by a person skilled in the art within the scope of the technical idea of the present invention. It is obvious that transformation can be made. In addition, even if not explicitly described and described the effects of the configuration of the present invention while describing the embodiments of the present invention, it is natural that the predictable effects of the configuration should also be recognized.

10: middle layer
20: surface layer
100: sandwich board

Claims (11)

Center layer; And a surface layer,
The center layer is a foam of a first thermoplastic resin,
The surface layer is a porous fiber-reinforced composite sheet comprising a reinforcing fiber and a binder resin of a second thermoplastic resin.
Sandwich board. The method of claim 1,
The first thermoplastic resin and the second thermoplastic resin are polyester, polyethylene terephthalate, polypropylene (PP), polyethylene (PE), acrylic butadiene styrene (ABS), polycarbonate (PC), nylon (Nylon), polychlorinated At least one selected from the group consisting of vinyl (PVC), polystyrene (PS), polyurethane (PU), polymethyl methacrylate (PMMA), polylactic acid (PLA), Teflon (polytetrafluoroethylene), and combinations thereof doing
Sandwich board. The method of claim 1,
The reinforcing fibers are bound by the binder resin to form an irregular network structure including pores.
Sandwich board. The method of claim 1,
The porous fiber reinforced composite sheet is a nonwoven fabric
Sandwich board. The method of claim 1,
The reinforcing fiber comprises at least one selected from the group consisting of aramid fiber, carbon fiber, carbon nanotube, boron fiber, metal fiber, and combinations thereof.
Sandwich board. The method of claim 1,
The surface layers are stacked on both sides of the center layer, respectively
Sandwich board. The method of claim 1,
The thickness of the sandwich board is 5 mm or more
Sandwich board. The method of claim 1,
The thickness ratio of the surface layer to the center layer is 1: 1.5 ~ 9
Sandwich board. The method of claim 1,
Additional molding is possible by applying heat
Sandwich board. The method of claim 1,
The porous fiber-reinforced composite sheet is manufactured by a wet papermaking method.
Sandwich board. The method of claim 1,
The basis weight ratio of the surface layer to the intermediate layer is 1: 1.5 ~ 9
Sandwich board.

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