KR20200136525A - Composite material preform board - Google Patents

Abstract

The present invention relates to a composite material preform board comprising: a reinforcing fiber; and polyphenylene sulfide and, more specifically, to a composite material preform board with excellent heat resistance and sound absorption properties.

Description

Composite material preform board {COMPOSITE MATERIAL PREFORM BOARD}

The present invention relates to a composite preformed board.

Conventional thermoplastic composites are composed of reinforcing fibers such as glass fibers or carbon fibers exhibiting high rigidity and a thermoplastic resin constituting a matrix. Since thermoplastic composites exhibit higher mechanical properties than general thermoplastic resin products, they are widely used as materials for automobiles and buildings. However, since such a thermoplastic composite material has high mechanical strength and low heat resistance, deterioration such as deformation of the material and a decrease in strength occurs under high temperature conditions.

Meanwhile, in order to compensate for the heat resistance of the thermoplastic resin, a thermosetting resin is substituted for the thermoplastic resin among composite materials. However, when the thermosetting resin is used, the manufacturing process is complicated, the manufacturing cost is increased, and the recyclability is poor.

An object of the present invention is to provide a composite preformed board excellent in heat resistance and sound absorption.

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, reinforcing fibers; And it provides a composite preformed board comprising polyphenylene sulfide.

The composite preformed board according to the present invention has excellent heat resistance and sound absorption.

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 is a graph showing the results of evaluating the thickness over time by leaving the preformed boards manufactured in Examples and Comparative Examples according to an embodiment of the present invention in an oven at 260°C.
2 is an outward-facing image obtained over time by leaving the preformed boards manufactured in Examples and Comparative Examples according to an embodiment of the present invention in an oven at 260°C.

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, when 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, reinforcing fibers; And it provides a composite preformed board comprising polyphenylene sulfide.

The composite preformed board may be formed including a pore structure. Typically, a composite material produced through a mold pressing process by mixing and extruding raw materials is difficult to form a pore structure, whereas the composite preformed board is produced by laminating at least two layers of porous fiber-reinforced composite sheets and then thermocompression bonding. Structure can be formed. In addition, the composite preformed board may adjust the porosity according to the degree of compression. Specifically, the composite preformed board may have a porosity of 5 to 80% by volume and may be adjusted to 20 to 60% by volume to achieve weight reduction while maintaining strength.

As such, the composite preformed board has excellent sound absorption performance as it forms a pore structure.

In one embodiment, the composite preformed board comprises reinforcing fibers; And at least two sheets of a porous fiber-reinforced composite material including polyphenylene sulfide may be stacked to be manufactured by a thermocompression bonding process.

In one embodiment, the porous fiber-reinforced composite sheet may be a nonwoven fabric manufactured by a dry process or a wet-laid process for a composition in which reinforcing fibers and polyphenylene sulfide fibrous particles are mixed.

The porous fiber-reinforced composite sheet may be a nonwoven fabric in which reinforcing fibers and the polyphenylene sulfide in the form of fibrous particles form an irregular network structure.

When at least two or more layers of the porous fiber-reinforced composite sheet are thermally compressed, the polyphenylene sulfide is melted to function as a binder. Accordingly, the composite preformed board is formed by binding the reinforcing fibers by the polyphenylene sulfide.

By thermocompression bonding at a temperature equal to or higher than the melting point of the polyphenylene sulfide, the polyphenylene sulfide may be melted during the thermocompression bonding process. During the thermocompression bonding process, some or all of the polyphenylene sulfide in the form of the fibrous particles may be melted. When the polyphenylene sulfide in the form of fibrous particles is partially melted, the shape of the fibrous particles can be partially maintained, and when all of the polyphenylene sulfide in the form of the fibrous particles is melted, the polyphenylene sulfide in the composite preformed board cannot maintain the shape of the fibrous particles. .

In one embodiment, the polyphenylene sulfide of the composite preformed board is completely melted and formed during the thermocompression bonding process, so that the shape of the fibrous particles cannot be maintained.

The reinforcing fiber may include at least one selected from the group consisting of glass fibers, aramid fibers, carbon fibers, carbon nanotubes, boron fibers, metal fibers, and combinations thereof. Examples of the metal fiber include nickel fiber, iron fiber, stainless steel fiber, copper fiber, aluminum fiber, silver fiber, and gold fiber.

Specifically, the reinforcing fiber may have a cross-sectional diameter of about 5 μm to about 40 μm. The reinforcing fibers having a thickness in the above range can appropriately impart strength and secure orientation and dispersibility. The composite preformed board including reinforcing fibers having a thickness in the above range is resistant to external impact, and when reinforcing fibers are dispersed in an aqueous solution during the manufacturing process of the porous fiber-reinforced composite sheet by a wet process, appropriate weaving properties in the aqueous solution It is possible to facilitate sheet formation by having the (Hydroentangle property).

The reinforcing fibers may have a length of about 1 mm to about 50 mm. The reinforcing fibers having a length in the above range can adequately impart strength, while securing orientation and dispersibility, and also appropriately impart a bonding force between fibrous particles so that the porous fiber-reinforced composite material has excellent strength and at the same time fiber When is too long, the fibers are lumped together to prevent deterioration in dispersibility, and is suitable for forming a sheet.

The composite preformed board includes polyphenylene sulfide and has excellent heat resistance.

The composite preformed board is prepared by first mixing polyphenylene sulfide as a raw material in the form of fibrous particles with reinforcing fibers, and then preparing a porous fiber-reinforced composite sheet according to a dry or wet process, and then stacking multiple sheets of it and thermocompression bonding. Therefore, it is possible to manufacture with a relatively simple manufacturing process that does not incur high cost. Therefore, when trying to manufacture a composite material using a thermosetting resin such as epoxy, the manufacturing process is complex and the problem of causing high cost is improved.

As mentioned above, since the composite preformed board has excellent sound absorption performance by forming a porous pore structure, it is suitable for application in applications requiring excellent mechanical strength and excellent sound absorption performance while implementing lightweight properties. For example, the composite preformed board is suitable for use as a lightweight material for parts requiring sound absorption performance, such as an undercover of a vehicle, a headliner, a wheelhouse cover, and a package tray.

Furthermore, recently, a porous composite material is required for heat insulation and noise reduction of engine parts, and since heat resistance is also required for this purpose, it is suitable for applying the composite preformed board. Existing composite materials with poor heat resistance suffer from deterioration such as deformation of the material and decrease in strength under high temperature conditions, and are vulnerable to fire, and thus cannot be used in the periphery of the engine. Since the composite preformed board has excellent heat resistance, it solves all of these problems and is suitable for application to parts located around the engine.

In one embodiment, since the composite preformed board is excellent in both heat resistance and sound absorption, it may be applied as an engine encapsulation material such as an engine cylinder block cover.

The weight ratio of the sum of the content of the reinforcing fiber to the content of polyphenylene sulfide in the composite preformed board may be about 20:80 to about 80:20, specifically, about 40:60 to about 60:40. As the content of the reinforcing fiber increases, the strength tends to be excellent, but the degree of improvement may decrease when the content is higher than a certain level. The content range is a suitable content range for effectively securing an effect of improving strength according to an increase in the content of the reinforcing fiber, and at the same time providing excellent weight reduction and sound absorption performance.

As described above, in order to manufacture the composite preformed board, the porous fiber-reinforced composite sheet must first be manufactured. When the porous fiber-reinforced composite sheet is manufactured by a wet process, polyphenylene sulfide may or may not be melted by controlling the temperature of the process of drying water or a solvent.

In one embodiment, the porous fiber-reinforced composite sheet may be manufactured by performing a drying process temperature above the melting point of polyphenylene sulfide to form a structure in which polyphenylene sulfide is melted to bind reinforcing fibers.

In one embodiment, when manufacturing the porous fiber-reinforced composite sheet, without performing a high-temperature process above the melting point of polyphenylene sulfide, a low melting point binder having a relatively low melting point is used together, and only the low melting point binder is melted to strengthen The porous fiber-reinforced composite sheet may be manufactured by forming a structure for binding fibers.

In one embodiment, the composite preformed board may further include a low melting point binder.

The low melting point binder is, for example, polyester, polyethylene, polypropylene, polyethylene (PE), acrylic butadiene styrene (ABS), polycarbonate (PC), nylon (Nylon), polyvinyl chloride (PVC), polystyrene ( PS), polyurethane (PU), polymethyl methacrylate (PMMA), polylactic acid (PLA), Teflon (polytetrafluoroethylene), and may include one selected from the group consisting of a combination thereof, but is not limited thereto. .

For example, the low melting point binder may be polypropylene or polyester.

The melting point of the low melting point binder does not have one specific value due to the characteristics of the resin, and may exist over a certain range of melting point ranges. A graph showing the melting amount of the low-melting-point binder while increasing the temperature in the melting point range is a graph similar to a normal distribution, and there is a peak at which the maximum amount of the low-melting-point binder melts, and the melting point at the peak is When defined as the melting point _max , the melting point _max of the low melting point binder may be a low melting point PET fiber of about 150 to about 170°C.

When the low-melting-point binder is added, there is an advantage that the porous fiber-reinforced composite sheet can be manufactured by performing a drying process at a relatively low temperature below the melting point of polyphenylene sulfide, but above the melting point of the low-melting-point binder.

The low melting point binder may have a melting range of about ±20°C at a melting point _max . Since there is a melting point range as in the above range, process control during thermoforming is easy, and workability can be improved.

The low-melting-point binder serves to bind the first thermoplastic resin fiber 11 and the reinforcing fiber, and can be melted at a low temperature by allowing the low-melting-point binder to have a melting point within the above range, so that the porous fiber-reinforced composite material Low temperature moldability can be secured during sheet manufacturing. The low melting point binder may be appropriately selected from a low melting point polyester, a low melting point polyethylene terephthalate, or polypropylene and polyethylene according to the molding temperature to be applied.

The content of the low melting point binder in the composite preformed board may be 5 to 10 wt%. By adding a low-melting-point binder in the above content range, while controlling the process temperature when manufacturing the porous fiber-reinforced composite sheet, it is possible to secure heat resistance by adding polyphenylene sulfide in a high content.

The composite preformed board may be manufactured to have a weight suitable for the intended use, for example, may be manufactured in the form of a plate having a weight of 50 g/m ² to 1200 g/m ² .

Specifically, it is possible to determine how many sheets of the porous fiber-reinforced composite sheet to be stacked according to the weight per unit area desired of the final product. For example, after laminating about 2 to 12 sheets of the porous fiber-reinforced composite sheet, heat and pressure are applied to heat press to manufacture a composite preformed board.

Specifically, in the hot press molding, a composite preformed board may be manufactured by laminating the porous fiber-reinforced composite sheet by applying a pressure of about 1 to about 30 bar at a temperature of about 100 to about 180°C.

The hot press molding may be performed so that the composite preformed board can be continuously manufactured by double belt press molding.

In addition, the composite preformed board may be manufactured in a compressed state as described above, and then expanded and molded by an additional molding process such as lofting. In the composite preformed board, the composite preformed board expands due to the restoring force of the reinforcing fibers as the binder is softened or melted when the temperature is raised and the binding force is relaxed.

The composite preformed board can exhibit excellent expandability in an additional molding process, and thus can be molded into various thicknesses during molding.

In order to maximize this expandability, a separate expansion agent may be added. As described above, since the composite preformed board has excellent expandability, it can be expanded to a predetermined level during subsequent molding without including an expansion agent. Thus, the composite preformed board may contain an inflating agent for a specific purpose, but the composite preformed board may not contain an inflating agent.

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

For polyphenylene sulfide fibers, fibers having a length of 6 mm and a thickness of 5 denier (about 21 μm cross-sectional diameter) were prepared in order to secure aqueous dispersion. As the reinforcing fiber, a glass fiber having a diameter of 16 µm and a length of 13 mm coated to be suitable for aqueous dispersion was prepared. 60 parts by weight of the polyphenylene sulfide fiber and 40 parts by weight of the glass fiber were mixed, and the mixture was stirred for 1 hour in an aqueous solution whose pH was adjusted to 2 with hydrochloric acid. At this time, the total content of polyphenylene sulfide and glass fiber was 2g per 1L of water. A wet papermaking process was performed to form a web through a vacuum suction device in the head box of the fiber slurry after the stirring process. After the web was formed, the moisture was completely dried by passing through an oven dryer at 130° C. to prepare a porous nonwoven sheet having a basis weight of 120 g/m ² . After 10 sheets were stacked to have a basis weight of 1200 g/m ² , a preformed board having a thickness of 2 mm was prepared by thermocompression bonding at a temperature of 300° C. using a hot press.

Example 2

50 parts by weight of the polyphenylene sulfide fiber and 40 parts by weight of glass fiber, and 10 parts by weight of a low-melting polyester fiber having a thickness of 4 denier (about 20 μm cross-sectional diameter) and a length of 5 mm were mixed in the same manner as in Example 1. The composite preformed board was completed.

Comparative Example 1

Instead of the polyphenylene sulfide fiber used in Example 1, 60 parts by weight of nylon-6 fiber having a length of 5 mm and a thickness of 4 denier and 40 parts by weight of the glass fiber were mixed, and a basis weight of 120 g/m ^{2 was used in} the same manner as in Example 1. A porous nonwoven sheet was prepared. After 10 sheets were stacked to have a basis weight of 1200 g/m ² , a preformed board having a thickness of 2 mm was prepared by thermocompression bonding at a temperature of 230° C. using a hot press.

Comparative Example 2

Instead of the polyphenylene sulfide fiber used in Example 1, 60 parts by weight of polyester fiber having a length of 5 mm and a thickness of 4 denier (about 20 µm cross-sectional diameter) and 40 parts by weight of the glass fiber were mixed in the same manner as in Example 1. A porous nonwoven sheet having a basis weight of 120 g/m ² was prepared. After 10 sheets were stacked to have a basis weight of 1200 g/m ² , a preformed board having a thickness of 2 mm was prepared by thermocompression bonding at 170° C. using a hot press.

Comparative Example 3

Instead of the polyphenylene sulfide fiber used in Example 1, 60 parts by weight of polypropylene fiber having a length of 5 mm and a thickness of 4 denier and 40 parts by weight of the glass fiber were mixed, and the porosity of a basis weight of 120 g/m ² was used in the same manner as in Example 1. A nonwoven sheet was prepared. After 10 sheets were stacked to have a basis weight of 1200 g/m ² , a preformed board having a thickness of 2 mm was prepared by thermocompression bonding at a temperature of 200° C. using a hot press.

evaluation

Experimental Example 1

For the preformed boards prepared in Example 1 and Comparative Examples 1-3, heat resistance performance was compared. A preformed board in the form of a plate having a thickness of 2 mm was left in an oven at 260° C. to evaluate the change in thickness and outward direction with time. The results are shown in Figures 1 and 2 below. In the case of Example 1, since polyphenylene sulfide was used as a binder, heat resistance was excellent, and even after heat treatment at 260° C. for 200 hours, the initial thickness was maintained and the original shape was maintained. However, in the preformed board prepared in Comparative Example 1-3, expansion in the thickness direction occurred as nylon-6, polyester, and polypropylene used as binders during heat treatment were melted or pyrolyzed. Particularly, the preformed board prepared in Comparative Example 3 exhibited a weight reduction rate of about 58% because polypropylene was thermally decomposed in a heat treatment process at 260° C. as polypropylene had the property of thermal decomposition at about 250°C.

The results are shown in Table 1 below.

Experimental Example 2

Mechanical properties were compared with respect to the preformed boards prepared in Example 1-2 and Comparative Example 1-3. After leaving the preformed boards prepared in Example 1-2 and Comparative Example 1-3 at room temperature for 24 hours, the tensile strength and tensile modulus were measured according to ASTM D638, and the flexural strength and flexural modulus were measured based on ASTM D790. I did. The preformed boards prepared in Example 1-2 and Comparative Example 1-3 were subjected to heat treatment at 260° C. for 100 hours, and then the flexural strength and tensile strength were measured in the same manner as described above. The results are shown in Table 1.

From the results of Table 1 above, Example 1-2 shows lower flexural strength and tensile strength than Comparative Example 1-3, and the polyphenylene sulfide used in Example 1-2 is a material due to its high brittle property. This is because it has a low limit of absorbing external stress applied to and is easily destroyed. The preformed board of Example 2 was formulated with a low melting point polyester fiber in a ratio of 10 parts by weight for the purpose of acting as a binder between reinforcing fibers at a low drying portion of about 130 °C when manufacturing a porous nonwoven fabric. It was confirmed that the mechanical properties were improved compared to Example 1 by supplementing the liver binding.

The preformed board prepared in Example 1-2 exhibited excellent mechanical property retention when exposed to high temperature conditions for a long time. In the preformed board of Example 2, it was confirmed that the heat resistance performance under high temperature conditions was not impaired when 10 parts by weight of the low melting point polyester fiber having low heat resistance was used. In the preformed board of Comparative Example 3, the polyproprylene binder was thermally decomposed by heat treatment at 260° C., so that only glass fibers, which are reinforcing fibers, remained, and mechanical properties could not be evaluated.

The tensile strength
(MPa) Tensile modulus
(GPa) Flexural strength
(MPa) Flexural modulus
(GPa) Example 1 Room temperature condition 18.4 2.54 23.7 2.68 Heat treatment at 260℃ for 100 hours 13.4 1.91 18.0 2.06 Example 2 Room temperature condition 22.8 2.85 25.4 2.71 Heat treatment at 260℃ for 100 hours 17.2 2.13 19.4 2.05 Comparative Example 1 Room temperature condition 37.4 2.91 39.5 2.91 Heat treatment at 260℃ for 100 hours 19.5 1.54 20.9 1.4 Comparative Example 2 Room temperature condition 51.0 3.22 56.1 3.7 Heat treatment at 260℃ for 100 hours 15.3 0.94 17.8 1.14 Comparative Example 3 Room temperature condition 45.1 3.01 47.4 3.12 Heat treatment at 260℃ for 100 hours - - - -

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.

Claims (7)

Reinforcing fibers; And a composite preformed board comprising polyphenylene sulfide. The method of claim 1,
The composite preformed board includes reinforcing fibers; And at least two sheets of a porous fiber-reinforced composite material containing polyphenylene sulfide are stacked to be prepared by a thermocompression bonding process.
Composite preform board. The method of claim 2,
The porous fiber-reinforced composite sheet is a nonwoven fabric in which the reinforcing fibers and the polyphenylene sulfide in the form of fibrous particles irregularly form a network structure.
Composite preform board. The method of claim 1,
The reinforcing fiber is formed by binding by the polyphenylene sulfide
Composite preform board. The method of claim 1,
The reinforcing fibers include at least one selected from the group consisting of glass fibers, aramid fibers, carbon fibers, carbon nanotubes, boron fibers, metal fibers, and combinations thereof.
Composite preform board. The method of claim 1,
5 to 10 wt% more containing a low melting point binder
Composite preform board. The method of claim 1,
The low melting point binder is polyester, polyethylene, polypropylene, polyethylene (PE), acrylic butadiene styrene (ABS), polycarbonate (PC), nylon (Nylon), polyvinyl chloride (PVC), polystyrene (PS), and polyurene. Tan (PU), polymethyl methacrylate (PMMA), polylactic acid (PLA), Teflon (polytetrafluoroethylene), including one selected from the group consisting of a combination thereof
Composite preform board.

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