KR102280425B1 - Porous fiber reinforced composite material and method of preparing the same - Google Patents

Abstract

A porous fiber-reinforced composite including a first layer and a second layer, wherein the first layer includes a first thermoplastic resin fiber, a first reinforcing fiber, and a first binder, and the second layer is a second thermoplastic resin fiber , a second reinforcing fiber and a second binder, wherein the length and diameter of the first thermoplastic resin fiber are respectively greater than the length and diameter of the second thermoplastic resin fiber, and the length and diameter of the first reinforcing fiber are respectively greater than the length and diameter of the second reinforcing fiber, and the first thermoplastic resin fiber and the first reinforcing fiber are bound by the first binder to form an irregular network structure including pores, and the second thermoplastic resin There is provided a porous fiber-reinforced composite material in which the fibers and the second reinforcing fibers are bound by the second binder to form an irregular network structure including pores.

Description

POROUS FIBER REINFORCED COMPOSITE MATERIAL AND METHOD OF PREPARING THE SAME

The present invention relates to a porous fiber-reinforced composite material and a method for manufacturing the same.

Conventional thermoplastic composite materials are composed of a reinforcing fiber such as glass fiber or carbon fiber exhibiting high rigidity and a thermoplastic resin constituting a matrix. Since these thermoplastic composite materials exhibit high mechanical properties compared to general thermoplastic resin products, they are widely used as materials for automobiles and constructions. The conventional method of manufacturing a thermoplastic composite material is mainly a method of mixing reinforcing fibers with a thermoplastic resin and then molding through an extrusion or mold press process. Recently, in order to improve strength and productivity, dry needle punching process or wet papermaking process is applied. First, a mat-type material containing reinforcing fibers is manufactured, and then a composite material is manufactured by impregnating the mat with resin.

Composite materials of reinforcing fibers and thermoplastic resins exhibit superior mechanical strength compared to thermoplastic resins because the reinforcing fibers act as reinforcing materials. As a method for increasing the strength of the reinforcing fiber composite material, a method of increasing the rigidity of the reinforcing fiber itself or increasing the ratio of the reinforcing fiber and a technique of improving the bonding force between the reinforcing fiber and the thermoplastic resin are applied. However, when a process for manufacturing a reinforcing fiber mat through a wet or dry process is introduced, there is a limit to improving strength through reinforcing fiber reforming.

One embodiment of the present invention provides a porous fiber-reinforced composite material that has excellent bending formability and excellent strength, and can achieve light weight and excellent sound absorption performance.

In one embodiment of the invention:

It is a porous fiber-reinforced composite comprising a first layer and a second layer,

The first layer includes a first thermoplastic resin fiber, a first reinforcing fiber, and a first binder,

The second layer includes a second thermoplastic resin fiber, a second reinforcing fiber, and a second binder,

The length and diameter of the first thermoplastic resin fiber is greater than the length and diameter of the second thermoplastic resin fiber,

The length and diameter of the first reinforcing fibers are greater than the length and diameter of the second reinforcing fibers, respectively,

The first thermoplastic resin fiber and the first reinforcing fiber are bound by the first binder to form an irregular network structure including pores,

The second thermoplastic resin fiber and the second reinforcing fiber are bound by the second binder to form an irregular network structure including pores.

A porous fiber-reinforced composite is provided.

In one embodiment of the invention:

forming a first nonwoven fabric layer by a dry method using a first mixed material including a first bicomponent fiber and a first reinforcing fiber;

forming a second nonwoven fabric layer by a wet method using a second mixed material including a second bicomponent fiber and a second reinforcing fiber; and

heat-sealing the first non-woven fabric layer and the second non-woven fabric layer;

including,

the length and diameter of the first bicomponent fiber are greater than the length and diameter of the second bicomponent fiber, respectively

A method of making a porous fiber-reinforced composite is provided.

The porous fiber-reinforced composite material has excellent bending formability and excellent strength, and, at the same time, implements light weight and excellent sound absorption performance.

1 is a schematic diagram of a porous fiber-reinforced composite material according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereto, and the present invention is only defined by the scope of the claims to be described later.

In one embodiment of the present invention, there is provided a porous fiber-reinforced composite including a first layer and a second layer. The first layer includes a first thermoplastic resin fiber, a first reinforcing fiber, and a first binder, the second layer includes a second thermoplastic resin fiber, a second reinforcing fiber, and a second binder, 1 The length and diameter of the thermoplastic resin fibers are greater than the length and diameter of the second thermoplastic resin fibers, the length and diameter of the first reinforcing fibers are respectively greater than the length and diameter of the second reinforcing fibers, the first thermoplastic resin fibers and the first reinforcing fiber is bound by the first binder to form an irregular network structure including pores, and the second thermoplastic resin fiber and the second reinforcing fiber are bound by the second binder to form pores to form an irregular network structure containing

1 schematically shows a cross-sectional view of a porous fiber-reinforced composite 100 according to an embodiment of the present invention.

As shown in FIG. 1 , the porous fiber-reinforced composite 100 has a multilayer structure of a first layer 10 and a second layer 20 .

In the first layer 10, the first thermoplastic resin fibers 11 and the first reinforcing fibers 12 are partially or entirely coated by the first binder 13 on the surface of each particle. A portion is formed, and the coating portions formed on the respective surfaces are fused to each other and bound.

Coating portions of each of the first thermoplastic resin fibers 11 and the first reinforcing fibers 12 may be fused, so that the first thermoplastic resin fibers 11 and the first reinforcing fibers 12 may be irregularly bonded. The first thermoplastic resin fibers 11 and the first reinforcing fibers 12 bound in this way can form an irregular network structure including the pores 14 .

The first thermoplastic resin fiber 11 and the first binder 13 may be formed from a core portion and a sheath portion of the first bicomponent fiber, respectively. When the sheath portion of the first bicomponent fiber is melted by heat-treating the structure in which the bicomponent fibers and the first reinforcing fibers 12 are irregularly mixed, a portion is transferred to the first reinforcing fiber 12, and the molten material of the sheath portion Part or all of the core portion of the bicomponent fiber and part or all of the first reinforcing fiber 12 are coated. When the melt of the sheath part is dried after coating the core part of the first bicomponent fiber and the first reinforcing fiber 12, the melt of the sheath part is solidified, and the sheath part of the first bicomponent fiber is formed of the first bicomponent fiber. The core part and the first reinforcing fiber 12 are bound. The core portion of the first bicomponent fiber is formed of the first thermoplastic resin fiber 11 , and the sheath portion of the first bicomponent fiber is formed of the first binder 13 .

The second layer 20 may also be manufactured in the same manner as the first layer 10 .

In the second layer 20, the second thermoplastic resin fibers 21 and the second reinforcing fibers 22 are partially or entirely coated by the second binder 23 on the surface of each particle. forming parts, and the coating parts formed on the respective surfaces are fused to each other and bound.

Similarly, the second thermoplastic resin fiber 21 and the second binder 23 may be formed from the core portion and the sheath portion of the second bicomponent fiber, respectively. When the sheath portion of the second bicomponent fiber is melted by heat-treating a structure in which the second bicomponent fiber and the second reinforcing fiber 22 are irregularly mixed, some of the second bicomponent fiber is transferred to the second reinforcing fiber 22, The melt of the second coats part or all of the core part of the second bicomponent fiber and part or all of the second reinforcing fiber 22 . When the melt of the sheath part is dried after coating the core part of the second bicomponent fiber and the second reinforcing fiber 22, the melt of the sheath part is solidified, and the sheath part of the second bicomponent fiber is the core part of the bicomponent fiber. and the second reinforcing fibers 22 are bound. The core portion of the bicomponent fiber is formed of the second thermoplastic resin fiber 21 , and the sheath portion of the second bicomponent fiber is formed of the second binder 23 .

Both the length and diameter of the first bicomponent fiber used to form the first layer 10 are greater than the length and diameter of the second bicomponent fiber used to form the second layer 20, Both the diameter and length of the first reinforcing fibers used to form the first layer 10 are larger than the diameter and length of the second reinforcing fibers used to form the second layer 20 .

As the diameter and length of the fibers included in the fiber-reinforced composite increase, it is advantageous for molding into a shape including a bent portion, but since the fiber density of the fiber-reinforced composite decreases, the strength of the fiber-reinforced composite decreases.

Conversely, the smaller the diameter and length of the fibers included in the fiber-reinforced composite, the higher the fiber density of the fiber-reinforced composite, the higher the strength of the fiber-reinforced composite, but the lower the bend formability.

The porous fiber-reinforced composite 100 is formed by laminating two layers prepared from two types of bicomponent fibers having different sizes, so that the formability and strength of the porous fiber-reinforced composite 100 are excellent at a certain level or higher. can be implemented

Specifically, the porous fiber-reinforced composite 100 implements better strength when the entire thickness is the same as compared to the case where only the first layer 10 having the larger diameter and length of the fiber is formed.

Specifically, the porous fiber-reinforced composite 100 implements better bending formability when the entire thickness is formed as compared to the case where only the second layer 20 having a smaller diameter and length of fibers is formed.

In addition, as the porous fiber-reinforced composite 100 is manufactured from two types of first and second bicomponent fibers having different sizes in each layer, the size of the pores 14 of each layer is different. As such, since the porous fiber-reinforced composite 100 has two layers of layers having different sizes of the pores 14, that is, the pores 14 of the porous fiber-reinforced composite 100 are in size. By forming the inclined structure, the sound absorption and insulation performance is improved.

The porous fiber-reinforced composite material 100 can be usefully applied to automotive interior materials, automotive exterior materials, and construction materials because it has excellent bending formability and excellent sound absorption and insulation performance while implementing excellent strength.

The first thermoplastic resin fiber 11 may have a cross-sectional diameter of about 14 μm to about 25 μm, and the second thermoplastic resin 21 may have a cross-sectional diameter of about 7 μm to about 14 μm.

For example, the first thermoplastic resin fiber 11 is formed by using the first bicomponent fiber as a material as described above, and has, for example, a cross-sectional diameter of about 20 μm to about 35 μm, and a core diameter. By using the first bicomponent fiber occupying about 14 μm to about 25 μm, the first thermoplastic resin fiber 11 having a cross-sectional diameter in the numerical range can be included in the first layer 10 . .

For example, the second thermoplastic resin fiber 21 is formed by using the second bicomponent fiber as a material as described above, and has, for example, a cross-sectional diameter of about 10 μm to about 20 μm, and a core diameter. The second layer 20 includes the second thermoplastic resin fiber 21 having a cross-sectional diameter in the numerical range using a second bicomponent fiber occupying about 7 μm to about 14 μm of the cross-sectional diameter. can make it

In addition, the first reinforcing fiber 12 may have a cross-sectional diameter of about 20 μm to about 40 μm, and the second reinforcing fiber 22 may have a cross-sectional diameter of about 6 μm to about 20 μm.

By forming the first thermoplastic resin fibers 11 and the second thermoplastic resin fibers 21 to be included in the first layer 10 and the second layer 20, respectively, so that the diameters of the fibers are different as described above, The strength of the porous fiber-reinforced composite 100 can be excellently implemented, and excellent bending formability can be implemented together.

The cross-sectional diameter of the fiber can be measured by SEM or an optical microscope.

The first thermoplastic resin fiber 11 (or the first bicomponent fiber) may have a length of about 40 mm to about 80 mm.

The second thermoplastic resin fiber 21 (or the second bicomponent fiber) may have a length of about 6 mm to about 18 mm.

The first reinforcing fibers 12 may have a length of about 40 mm to about 80 mm.

The second reinforcing fibers 22 may have a length of about 6 mm to about 18 mm.

By forming the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21 to be included in the first layer 10 and the second layer 20, respectively, so that the length of the fiber is different as described above, The strength of the porous fiber-reinforced composite 100 can be excellently implemented, and excellent bending formability can be implemented together.

When using the first bicomponent fiber having the diameter and length of the fiber as described above, it is suitable to apply the dry process. Accordingly, the first layer 10 may be manufactured by a dry process.

When the second bicomponent fiber having the diameter and length of the fiber as described above is used, it is suitable for applying the wet process. Accordingly, the second layer 20 may be manufactured by a wet process.

After each of the first layer 10 and the second layer 20 are prepared, the porous fiber-reinforced composite 100 may be manufactured by laminating them. For example, after manufacturing the first layer 10 and the second layer 20 in the form of a nonwoven fabric by a dry process and a wet process, respectively, the first layer 10 and the second layer 20 By heat-sealing the porous fiber-reinforced composite material 100 can be manufactured. When the first layer 10 and the second layer 20 are heat-sealed, the first binder 13 and the second binder 23 in contact with each other may be heat-sealed to each other.

The first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21 (the core part of the bicomponent fiber) include polyester, polypropylene (PP), polyethylene (PE), acrylbutadiene styrene (ABS), poly Carbonate (PC), nylon (Nylon), polyvinyl chloride (PVC), polystyrene (PS), polyurethane (PU), polymethyl methacrylate (PMMA), polylactic acid (PLA), Teflon (polytetrafluoroethylene) and It may include one selected from the group consisting of combinations thereof.

Specifically, the melting point of the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21 may be about 160 ℃ or more. More specifically, the melting point of the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21 may be about 200 ℃ to about 400 ℃. By making the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21 have melting points within the above range, the first binder 13 and the second binder 23 are melted during molding. Even after that, the fibrous form can be maintained. When the melting point of the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21 is less than 160° C., the thermoforming temperature must be too low to maintain the fibrous shape, or the porous fiber-reinforced composite 100 comprising the same There is a risk that thermal stability may be lowered later, resulting in dimensional deformation or polymer deterioration. In addition, since the temperature difference between the first binder 13 and the second binder 23 may be excessively reduced, it may be difficult to control the molding temperature.

For example, the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21 may include polyethylene terephthalate.

The first binder 13 and the second binder 23 (sheath portion of the bicomponent fiber) are, 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 combinations thereof, but is not limited thereto.

For example, the first binder 13 and the second binder 23 may be polypropylene or polyester.

The melting points of the first binder 13 and the second binder 23 do not have one specific value due to the characteristics of the resin, and may exist over a certain range of melting points. A graph showing the amount of melting of the first binder 13 or the second binder 23 while increasing the temperature in the melting point range is a graph similar to a substantially normal distribution, and the first binder 13 ) or a peak in which the maximum amount of the second binder 23 is melted exists, and when the melting point at the peak _{is defined as the melting point max} , the first binder 13 or the second binder 23 Melting point _max may be about 150 to about 170 ℃ low melting point PET fiber.

As described above, the first binder 13 and the second binder 23 correspond to the sheath portion of the bicomponent fiber. _{The bicomponent fiber includes a sheath portion having a lower melting point max} of about 150 to about 170° C. compared to the core portion, and as it can be formed in the range of the temperature conditions, it is easy to optimize the process conditions during thermoforming, and stability can be ensured.

In addition, the first binder 13 or the second binder 23 may have a melting range of about ±20° C. from the _{melting point max.} By applying the second thermoplastic resin having a melting point range as in the above range to the sheath portion of the bicomponent fiber, process control during thermoforming is easy and workability is improved.

The first binder 13 and the second binder 23 may include a first thermoplastic resin fiber 11 and a first reinforcing fiber 12 or a second thermoplastic resin fiber 21 and a second reinforcing fiber 22 . ) and serves to bind the first binder 13 or the second binder 23 to have a melting point in the above range so that it can be melted at a low temperature, thereby ensuring low-temperature formability. The first binder 13 and the second binder 23 may be appropriately selected from low-melting-point polyester, low-melting-point polyethylene terephthalate, or polypropylene and polyethylene, depending on the molding temperature to be applied.

As described above, when selecting the first thermoplastic resin fiber 11 , the second thermoplastic resin fiber 21 , the first binder 13 and the second binder 23 as in the above example, the first The melting point of the thermoplastic resin fiber 11 is higher than the melting point of the first binder 13 , and the melting point of the second thermoplastic resin fiber 21 is higher than the melting point of the second binder 23 . In addition, the materials of the first bicomponent fiber and the second bicomponent fiber are appropriately selected so that the materials of the core part and the sheath part of the bicomponent fiber used in the method for manufacturing the porous fiber-reinforced composite material 100 to be described later satisfy the above conditions, respectively. can

The first binder 13 and the second binder 23 are derived from the sheath of the bicomponent fiber as a raw material, and the porous fiber-reinforced composite 100 may not use an additional binder separately. .

The first reinforcing fiber 12 and the second reinforcing fiber may include one selected from the group consisting of glass fibers, aramid fibers, carbon fibers, carbon nanotubes, boron fibers, metal fibers, and combinations thereof. not limited Examples of the metal fibers include nickel fibers, iron fibers, stainless steel fibers, copper fibers, aluminum fibers, silver fibers, gold fibers, and the like.

The porous fiber-reinforced composite material 100 includes two types of fibrous particles of a first thermoplastic resin fiber 11 and a first reinforcing fiber 12 in a first layer 10, and a second layer 20 The second thermoplastic resin fiber 21 and the second reinforcing fiber 22 also include two types of fibrous particles. Each layer of the porous fiber-reinforced composite 100 includes a first thermoplastic resin fiber 11 (or a second thermoplastic resin fiber 21) and a first reinforcing fiber 12 (or a second reinforcing fiber 22). By including all of them together, the type and content ratio can be adjusted to be designed so that predetermined characteristics are excellently expressed.

In one embodiment, the weight ratio of the sum of the content of the first reinforcing fiber 12 to the content of the first thermoplastic resin fiber 11 and the first binder 13 in the first layer 10 is about 20:80 to about 80:20, specifically, about 40:60 to about 60:40. As the content of the first reinforcing fibers 12 increases, the strength tends to be excellent, but the degree of improvement may be lowered above a certain content level. The content range is suitable for effectively securing the effect of improving the strength according to the increase in the content of the first reinforcing fiber 12 , and at the same time obtaining the effect from the first thermoplastic resin fiber 11 .

Similarly, in the second layer 20 , the weight ratio of the content of the second reinforcing fiber 22 to the sum of the content of the second thermoplastic resin fiber 21 and the second binder 23 is about 20:80 to about 80:20, specifically, about 40:60 to about 60:40.

The first layer 10 may include about 40 parts by weight to about 250 parts by weight of the first binder 13 based on 100 parts by weight of the first thermoplastic resin fiber 11 . By adjusting the content ratio of the first reinforcing fibers 12 and the first binder 13 to the above content ratio, it is possible to properly impart binding force and elasticity while maintaining excellent dispersibility.

Similarly, the second layer 20 may include about 40 parts by weight to about 250 parts by weight of the second binder 23 based on 100 parts by weight of the second thermoplastic resin fiber 21 .

By adjusting the content ratio of the core part and the sheath part of the first bicomponent fiber and the second bicomponent fiber as the raw material, the weight ratio between the first thermoplastic resin fiber 11 and the first binder 13 or the second A weight ratio between the thermoplastic resin fiber 21 and the second binder 23 may be implemented.

Each layer of the porous fiber-reinforced composite 100 forms open pores 14 while forming a network structure. For example, by allowing the porosity of the porous fiber-reinforced composite 100 to have a porosity of about 30 to about 80% by volume, the porous fiber-reinforced composite 100 can implement weight reduction while maintaining strength, and with excellent absorption It may have sound insulation performance.

The sound wave entering through the open pores 14 of the porous fiber-reinforced composite 100 is attenuated by the vibration of the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21, so it is applied as a sound absorbing and insulating material. This becomes possible. The higher the porosity of the porous fiber-reinforced composite 100, the higher the content of the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21, and the longer the length through which the sound wave passes, the longer the energy is attenuated. The effect is excellent. The length through which the sound wave passes is, for example, longer when the thickness of the material itself is large or the connectivity of the pores 14 is good, even if they have the same porosity. The porous fiber-reinforced composite material 100 maintains a certain degree of porosity, while controlling the content of the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21, and the length through which the sound wave passes. can be manufactured as a material having improved sound absorbing and insulating performance by controlling them together. In particular, since the first thermoplastic resin fiber 11 and the second thermoplastic resin fiber 21 are softer than the hard first reinforcing fiber 12 and the second reinforcing fiber 22, the sound energy attenuation effect is high and absorption It works effectively to improve sound insulation performance.

In the porous fiber-reinforced composite 100, the size of the pores 14 formed by the first layer 10 and the second layer 20 is different because they contain fibers having different diameters from each other. do. The pores 14 formed by being surrounded by fibers having a larger diameter of the first layer 10 are larger than the pores 14 formed by being surrounded by fibers having a smaller diameter in the second layer 20 . As such, in the porous fiber-reinforced composite 100 , the sizes of the pores 14 formed in the first layer 10 and the second layer 20 are different, thereby forming an inclined pore structure. Since the inclined pore structure is formed, the porous fiber-reinforced composite material 100 may exhibit excellent sound absorption and insulation performance.

Specifically, the difference in the size of the pores can be measured through SEM. For example, in the second layer 20, the average diameter of the pores may be about 30㎛ to about 80㎛, the average diameter of the pores 14 of the first layer 10 is about 50㎛ to about It may be 200 μm.

The average diameter of the pores can be calculated from the diameters of the pores measured by SEM or optical microscope.

In addition, such a pore structure can be inferred through air permeability measurement. If the air permeability value of each layer of the porous fiber-reinforced composite material is large, it can be considered that the average pore diameter is formed large, and conversely, when the air permeability value is small, it may mean that the average pore diameter is also formed small.

Breathability can be measured with the FX 3300 LabAir IV from TEXTEST INSTRUMENTS.

For example, in the porous fiber-reinforced composite, the air permeability of the first layer formed to a thickness of about 2 mm may be from about 5.8 l/min to about 7.1 l/min, and formed to a thickness of about 2 mm in the porous fiber-reinforced composite. The air permeability of the second layer may be from about 3.6 l/min to about 4.4 l/min (applying an error rate of 10%).

The porous fiber-reinforced composite material 100 has excellent strength and bending formability by appropriately adjusting the ratio between the first layer 10 and the second layer 20, and also has excellent sound absorbing and insulating performance. can be implemented

In one embodiment, the basis weight ratio (g/m ² ) of the first layer 10 and the second layer 20 may be about 2:8 to about 8:2.

The first layer 10 is suitable to be manufactured by a dry process because the diameter of the first thermoplastic resin fiber 11 is relatively large. Accordingly, the first layer 10 may be a nonwoven fabric manufactured by a dry needle punching process.

The second layer 20 is suitable to be manufactured by a wet process because the diameter of the second thermoplastic resin fiber 21 is relatively small. Accordingly, the second layer 20 may be a nonwoven fabric manufactured by a wet process.

As described above, the porous fiber-reinforced composite 100 may be manufactured by separately manufacturing the first layer 10 and the second layer 20 and laminating them.

In one embodiment of the present invention, the method comprising: forming a first nonwoven fabric layer by a dry method using a first mixed material including a first bicomponent fiber and a first reinforcing fiber 12; forming a second nonwoven layer by a wet method using a second mixed material comprising second bicomponent fibers and second reinforcing fibers 22; and heat-sealing the first non-woven fabric layer and the second non-woven fabric layer. It provides a method of manufacturing a porous fiber-reinforced composite material comprising a. The length and diameter of the first bicomponent fiber are greater than the length and diameter of the second bicomponent fiber, respectively.

By the method of manufacturing the porous fiber-reinforced composite material, the above-described porous fiber-reinforced composite material 100 may be manufactured. Accordingly, detailed descriptions of the first bicomponent fiber, the first reinforcing fiber 12 , the second bicomponent fiber, and the second reinforcing fiber 22 are the same as described above.

Accordingly, the core portion of the first bicomponent fiber becomes the first thermoplastic resin fiber 11 included in the obtained porous fiber-reinforced composite 100, and the sheath portion of the first bicomponent fiber is the obtained porous fiber-reinforced composite 100. It becomes the first binder 13 included in the. Similarly, the core portion of the second bicomponent fiber becomes the second thermoplastic resin fiber 21 included in the obtained porous fiber-reinforced composite 100, and the sheath portion of the second bicomponent fiber becomes the obtained porous fiber-reinforced composite 100. The second binder 23 included in the .

In the method of manufacturing the porous fiber-reinforced composite, the first nonwoven layer corresponds to the first layer 10 of the porous fiber-reinforced composite 100 described above, and the second nonwoven layer is the above-described porous fiber-reinforced composite material. (100) corresponds to the second layer (20).

When the first nonwoven fabric layer and the second nonwoven fabric layer are heat-sealed, a component resulting from the sheath portion of the first bicomponent fiber in the first nonwoven fabric layer and the sheath portion of the second bicomponent fiber in the second nonwoven fabric layer The resulting components are fused to each other.

The porous fiber-reinforced composite 100 may be manufactured to have a weight suitable for the intended use, for example, a sheet having a weight of ^{about 50 g/m 2} to about 1200 g/m ^{2 It may be manufactured} .

The plate of the porous fiber-reinforced composite 100 may be formed by pressing at least two or more sheets of the porous fiber-reinforced composite 100, and specifically, how many sheets to fit the desired unit area weight of the final product You can decide whether to stack or not. For example, if the final unit area weight of the desired product is 1200 g/m ² , approximately 2 to 12 sheets of the porous fiber-reinforced composite material 100 are laminated, and then heat and pressure are applied to heat press molding to form porous fibers A plate of the reinforced composite 100 may be manufactured.

The hot press molding may be performed at a temperature at which the binder or coating part resulting from the sheath of the bicomponent fiber as a raw material can be melted, and at a temperature at which the core part of the bicomponent fiber as a raw material does not melt. When it is carried out in this temperature range, the interface between the sheets of the porous fiber-reinforced composite 100 may be fused while the binder or coating portion resulting from the sheath is melted.

Specifically, the heat press molding is performed by laminating the sheet of the porous fiber-reinforced composite 100 by applying a pressure of about 1 to about 30 bar at a temperature of about 100 to about 180° C. to form a plate of the porous fiber-reinforced composite 100. can be manufactured.

The heat press molding may be performed so that the plate material of the porous fiber-reinforced composite material 100 can be continuously manufactured by double belt press molding.

The press molding may be performed at a compression ratio of about 80 to about 95%. By controlling the compression density of the fiber by the press molding, it is possible to achieve excellent strength and sound absorption properties.

The plate material is formed to include a pore structure. In general, a composite material manufactured through a mold press process by mixing and extruding raw materials is difficult to form a pore structure, whereas the plate material forms a pore structure as it is manufactured using the porous fiber-reinforced composite material 100 .

Specifically, the plate material may have a porosity of about 40 to about 80% by volume. Since the plate of the porous fiber-reinforced composite 100 is formed to have a porosity within the above range, the strength, impact resistance and sound absorption properties of the plate of the porous fiber-reinforced composite 100 can all be excellent.

Since the plate of the porous fiber-reinforced composite 100 is in a compressed state of the porous fiber-reinforced composite 100, its structure may be understood as the compressed form of the porous fiber-reinforced composite 100 of FIG. 1 as it is.

Specifically, the plate material may be manufactured by performing press molding such that the density of the plate material is about 0.2 g/cm ³ to about 1.6 g/cm ^{3 .} It is manufactured by pressing the density of the plate to be within the above range, so that excellent strength can be realized.

The plate material can implement high mechanical strength, such as tensile, flexural and impact strength, while having a low density, so that it can be lightweight, and since it is a material that implements sound absorbing and insulating performance, it is useful for use in automobiles and building materials that require these characteristics. can be applied. In addition, the plate material can satisfy the excellent sound absorption and insulation performance conditions required for such materials for automobiles and constructions.

The plate of the porous fiber-reinforced composite 100 may be manufactured to have a weight suitable for the intended use, for example, from about 600 g/m ² to about 3000 g/m ² , for example, about 900 g /m ² to about 1400 g/m ² may have a basis weight.

The plate material of the composite porous fiber-reinforced composite 100 may have a thickness of about 2 mm to about 8 mm.

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 One

(1) Preparation of the first layer

A polyethylene terephthalate (PET) single component fiber (first reinforcing fiber) having a cross-sectional average diameter of 30 μm, an average length of 51 mm, and a melting point of 250° C. to 270° C. was prepared. In addition, the cross-sectional average diameter is 28㎛, the average length is 51mm, the melting point of the core portion containing polyethylene terephthalate (PET) having a high melting point of 250 °C to 270 °C and a low melting point of 160 °C to 180 °C. A sheath-core type first bicomponent fiber including polyethylene terephthalate (PET) was prepared. At this time, the diameter of the core part is 20㎛, and the thickness of the sheath part is 8㎛. The first reinforcing fibers to the first bicomponent fibers were mixed in a weight ratio of 40:60.

Then, the mixed fibers were first physically bonded to each other through carding, and then the physical bonding force between the fibers was strengthened through a needle punching process to prepare a nonwoven sheet.

(2) Second layer manufacturing

The second bicomponent fiber has a weight ratio of 50:50 to the polyester core part and the low-melting polyester sheath part, and has a length of 12mm and a thickness of 2 denier (about 14㎛ cross-sectional diameter, core part) to ensure water-based dispersibility. A fiber having a diameter of 10 μm) was prepared. The second reinforcing fiber was prepared by cutting a polyethylene terephthalate (PET) fiber of 1.4 denier (about 12 μm cross-sectional diameter) coated to be suitable for aqueous dispersion into a length of 13 mm. 40 parts by weight of the second reinforcing fiber and 60 parts by weight of the second bicomponent fiber were blended, and this was stirred for 1 hour in an aqueous solution having a pH adjusted to 2 with hydrochloric acid. At this time, 40 parts by weight of the second reinforcing fiber and the total content of the second bicomponent fiber were 2 g per 1 L of water. A wet papermaking process was performed to form a web of the aqueous solution slurry subjected to the stirring process through a vacuum suction device in the head box. After the web was formed, the moisture was completely dried by passing through an oven dryer at 140° C. to prepare a nonwoven sheet. The dried nonwoven sheet exhibited a thickness of approximately 1.5 mm at 200 g/m ^{2 .}

(3) Lamination

After stacking 3 sheets of 200 g/m ^{2 of} the second layer to 600 g/m ² , the first layer of 600 g/m ² was laminated thereon so that the basis weight ratio of the two layers was 1:1 (a total of 1200 g/m 2 ) ² ). It was molded into a composite preformed board with a thickness of 5mm through a double belt press facility at 200°C.

(4) sheet material manufacturing

After preheating the composite preformed board prepared in this way at 200°C for 5 minutes in a convection oven, it was transferred to a mold press at room temperature, and then mold pressing was performed by applying a pressure of 1 bar to the final mold formed with an average thickness of 2.0mm. The product was completed.

Example 2

The final product was completed with the exception of a point such that the second in the same manner as in Example 1: first by laminating a first layer 400g / m ² and the second layer 800g / m ² basis weight ratio of 1.

Example 3

The final product was finished in one and the same method as in Example 1 except for a point such that: a first layer non-woven fabric layer 800g / m ² non-woven fabric layer and the second layer 400g / m ² by laminating a basis weight ratio of 2.

Example 4

A final product was completed in the same manner as in Example 1, except that a second bicomponent fiber having a length of 6 mm was used in the second layer.

Example 5

A final product was prepared in the same manner as in Example 1, except that a bicomponent fiber having a length of 18 mm was used in the second layer.

comparative example One

A first layer was prepared in the same manner as in Example 1. ^Two layers of 600 g/m 2 of the first layer were laminated (total of 1200 g/m ² ). It was molded into a composite preformed board with a thickness of 5mm through a double belt press facility at 200°C. The composite preformed board thus prepared was expanded through preheating at 200° C. for 2 minutes in an IR oven, transferred to a mold press at room temperature, and then mold pressed by applying 1 bar pressure to form a final mold with an average thickness of 2.0 mm The molded product was completed.

comparative example 2

A second layer was prepared in the same manner as in Example 1. Six layers of 200 g/m ^{2 of} the second layer are laminated (total of 1200 g/m ² ). It was molded into a composite preformed board with a thickness of 5mm through a double belt press facility at 200°C. The composite preformed board thus prepared was expanded through preheating at 200° C. for 2 minutes in an IR oven, transferred to a mold press at room temperature, and then mold pressed by applying 1 bar pressure to form a final mold with an average thickness of 2.0 mm The molded product was completed.

evaluation

Experimental example 1 (air permeability)

In order to check the difference in porosity, the air permeability was measured for the samples of the final mold-molded products of Comparative Example 1 and Comparative Example 2 made only of the first layer nonwoven fabric and the second layer nonwoven fabric only.

The air permeability was measured through FX 3300 LabAir IV of TEXTEST INSTRUMENTS, and the area of the specimen was 38 cm ² and the pressure standard for measurement is 125 Pa.

The air permeability of the first layer was 6.38 l/min, and the air permeability of the second layer was about 4.03 l/min.

From the difference in air permeability, it was indirectly confirmed that the pores of the first layer were formed larger than that of the second layer.

Experimental example 2 (flexural strength and flexural modulus)

With respect to the final molded products prepared in Examples 1-5 and Comparative Examples 1-2, the mechanical properties of flexural strength and flexural modulus were compared. Flexural strength was measured after the final molded product was left at room temperature for 24 hours, respectively.

Flexural strength and flexural modulus were measured according to ASTM D790 for a sample in which the final molded product had a thickness of 2 mm. The results are shown in Table 1.

division Flexural strength (MPa) Flexural Modulus (GPa) Example 1 25.5 1.58 Example 2 26.6 1.56 Example 3 22.5 1.18 Example 4 26.2 1.62 Example 5 24.8 1.34 Comparative Example 1 21.0 1.05 Comparative Example 2 27.5 1.69

Experimental example 4( high temperature tensile elongation )

150 mm wide from the final molded products prepared in Examples 1-5 and Comparative Examples 1-2. After taking 5 samples with a length of 25 mm, placing the sample on a jig of a tensile tester, putting the sample and the jig in an oven at 150° C., holding the jig for 3 minutes, and then measuring according to ASTM D 638 in the oven. After stretching the specimen, the stretching length when cutting was measured.

The results are shown in Table 2.

division High-temperature tensile elongation length (mm) Example 1 64 Example 2 51 Example 3 85 Example 4 55 Example 5 66 Comparative Example 1 102 Comparative Example 2 15

Experimental example 4 (Evaluation of moldability)

The upper mold and lower mold were made to correspond to the cone-shaped cup shape with an upper 30 mm diameter and a lower 55 mm diameter. After preheating the composite preformed boards prepared in Examples 1-5 and Comparative Examples 1-2 at 200° C. for 5 minutes in a convection oven, it was mounted on the mold and applied to a pressure of 1 bar at room temperature to produce a cup-shaped final product. did. The final product was evaluated for moldability in 5 grades according to the criteria of Table 3 by 4 evaluators. (Sensory index evaluation)

Sample
formability
rank level rank Evaluation standard Great 5 No abnormality in appearance and strength 4 Good appearance but lower strength 3 upper tear 2 side tear bad One complete fracture of the side

The results are shown in Table 4.

division evaluation Example 1 5 Example 2 3 Example 3 5 Example 4 4 Example 5 5 Comparative Example 1 5 Comparative Example 2 2

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also present. It belongs to the scope of the invention.

10: 1st floor
20: 2nd floor
11: first thermoplastic resin fiber
12: first reinforcing fiber
13: first binder
14: Qigong
21: second thermoplastic resin fiber
22: second reinforcing fiber
23: second binder
100: porous fiber-reinforced composite material

Claims (14)

It is a porous fiber-reinforced composite comprising a first layer and a second layer,
The first layer includes a first thermoplastic resin fiber, a first reinforcing fiber, and a first binder,
The second layer includes a second thermoplastic resin fiber, a second reinforcing fiber, and a second binder,
The length and diameter of the first thermoplastic resin fiber are greater than the length and diameter of the second thermoplastic resin fiber, respectively,
The length and diameter of the first reinforcing fibers are greater than the length and diameter of the second reinforcing fibers, respectively,
The first thermoplastic resin fiber and the first reinforcing fiber are bound by the first binder to form an irregular network structure including pores,
The second thermoplastic resin fiber and the second reinforcing fiber are bound by the second binder to form an irregular network structure including pores.
Porous fiber-reinforced composites.
According to claim 1,
The first thermoplastic resin fiber and the first reinforcing fiber are partially or wholly coated on the surface of each particle by the first binder to form a coating portion, and the coating portion formed on each surface is fused to each other and bound,
The second thermoplastic resin fiber and the second reinforcing fiber are partially or entirely coated on the surface of each particle by the second binder to form a coating portion, and the coating portion formed on each surface is fusion bonded to each other.
Porous fiber-reinforced composites.
According to claim 1,
The first thermoplastic resin fiber has a cross-sectional diameter of 14 μm to 20 μm,
The second thermoplastic resin fiber has a cross-sectional diameter of 7 μm to 14 μm.
Porous fiber-reinforced composites.
According to claim 1,
The first reinforcing fiber has a cross-sectional diameter of 20 μm to 40 μm,
The second reinforcing fiber has a cross-sectional diameter of 6 μm to 20 μm
Porous fiber-reinforced composites.
According to claim 1,
The first thermoplastic resin fiber has a length of 40 mm to 80 mm,
The second thermoplastic resin fiber has a length of 6 mm to 18 mm
Porous fiber-reinforced composites.
According to claim 1,
The first reinforcing fiber has a length of 40 mm to 80 mm,
The second reinforcing fiber has a length of 6 mm to 18 mm.
Porous fiber-reinforced composites.
According to claim 1,
The air permeability of the first layer is 5.8 l/min to 7.1 l/min, and the air permeability of the second layer is 3.6 l/min to 4.4 l/min sign
Porous fiber-reinforced composites.
According to claim 1,
The basis weight ratio (g/m ² ) of the first layer and the second layer is 2: 8 to 8: 2
Porous fiber-reinforced composites.
According to claim 1,
The first thermoplastic resin fiber and the second thermoplastic resin fiber are polyester, polypropylene (PP), polyethylene (PE), acrylbutadiene styrene (ABS), polycarbonate (PC), nylon (Nylon), polyvinyl chloride ( PVC), polystyrene (PS), polyurethane (PU), polymethyl methacrylate (PMMA), polylactic acid (PLA), Teflon (polytetrafluoroethylene) and containing one selected from the group consisting of combinations thereof
Porous fiber-reinforced composites.
According to claim 1,
The first binder and the second binder include polyester, polyethylene, polypropylene, polyethylene (PE), acrylbutadiene styrene (ABS), polycarbonate (PC), nylon (Nylon), polyvinyl chloride (PVC), polystyrene (PS), polyurethane (PU), polymethyl methacrylate (PMMA), polylactic acid (PLA), including one selected from the group consisting of Teflon (polytetrafluoroethylene) and combinations thereof
Porous fiber-reinforced composites.
According to claim 1,
The first reinforcing fiber and the second reinforcing fiber include one selected from the group consisting of glass fibers, aramid fibers, carbon fibers, carbon nanotubes, boron fibers, metal fibers, and combinations thereof.
Porous fiber-reinforced composites.
According to claim 1,
The melting points of the first and second thermoplastic resins are 160° C. or higher.
Porous fiber-reinforced composites.
According to claim 1,
The melting points of the first binder and the second binder are less than 200 °C.
Porous fiber-reinforced composites.
forming a first nonwoven fabric layer by a dry method using a first mixed material including a first bicomponent fiber and a first reinforcing fiber;
forming a second nonwoven fabric layer by a wet method using a second mixed material including a second bicomponent fiber and a second reinforcing fiber; and
heat-sealing the first non-woven fabric layer and the second non-woven fabric layer;
including,
the length and diameter of the first bicomponent fiber are greater than the length and diameter of the second bicomponent fiber, respectively
A method of making a porous fiber-reinforced composite.

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