KR20230163331A - Apparatus for manufacturing of single layer sound adsorbing material having hybrid pad randomly mixed with meltblown fiber and nano fiber for reducing noise in audio frequency band and sound adsorbing material manufactured using the same - Google Patents

Abstract

The present invention relates to an apparatus for manufacturing a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers are randomly mixed, and to a sound-absorbing material manufactured thereby, wherein a base sound-absorbing pad, a fastener, and a hybrid sound-absorbing pad are sequentially formed. A porous pedestal on which a sound-absorbing material for noise reduction in the audible frequency band is placed, which is laminated and is composed of a thin film thermoplastic melt-type adhesive material with a fastener structure allowing ventilation; A heater that provides heat for melting the adhesive material provided on the fastener on one side of the sound-absorbing material seated on the pedestal; And a suction that absorbs the heat of the heater along with the air from the other side of the sound absorbing material and transmits the heat in the thickness direction of the sound absorbing material. It includes a base sound absorbing pad and hybrid sound absorbing material of the sound absorbing material by an adhesive material provided on the fastener that is melted by the heat of the heater. By laminating pads, a sound-absorbing material for noise absorption can be manufactured.

Description

Apparatus for manufacturing sound-absorbing material for noise reduction in the audible frequency band, including a single-layer hybrid sound-absorbing pad in which melt-blown fibers and nanofibers are randomly mixed, and sound-absorbing material manufactured thereby RANDOMLY MIXED WITH MELTBLOWN FIBER AND NANO FIBER FOR REDUCING NOISE IN AUDIO FREQUENCY BAND AND SOUND ADSORBING MATERIAL MANUFACTURED USING THE SAME}

The present invention relates to a sound-absorbing material manufacturing apparatus, and more specifically, to a sound-absorbing material manufacturing apparatus for sound absorption of noise and a sound-absorbing material manufactured thereby.

In general, a non-woven fabric type sound-absorbing material is used as a sound-absorbing material for the purpose of absorbing sound to reduce noise. This type of non-woven sound absorbing material is mainly used in the automobile and construction fields. As many fibers intersect on the surface and inside of the non-woven fabric, small bubbles or tube-shaped holes are formed, and the air in the holes vibrates due to sound waves, causing friction. As sound energy is absorbed, noise is reduced.

In order to manufacture such a non-woven sound absorbing material, conventionally, a device was used to produce a non-woven sound absorbing material by forming a fiber web using a meltblown method.

Nonwoven fabrics composed of a single layer of melt-blown web have been used by the melt-blown method. The meltblown spinning device for producing such a single-layer meltblown web-type nonwoven fabric can produce ultramicrofibers with a diameter of submicron to several microns, but there are limitations to the applicable polymers and it is necessary to improve the performance of the filter material. There were limits to the miniaturization of the fiberscope.

Accordingly, a fiber web was formed with nanofibers using an electrospinning method to manufacture a sound-absorbing material in the form of a non-woven fabric made of nanofibers. However, the production of nanofibers using the electrospinning method is one of the methods that can achieve the above-mentioned miniaturization of the fiber diameter and improved performance of the filter material. However, the electrospinning method is a solution spinning method, so the process yield is low for the spinning solution used to manufacture nanofibers. It is only less than 30%, and the manufacturing cost of the product is high because the processing costs, such as the need to recover or dispose of the used solvent, are high. In addition, due to low mechanical strength, nanofiber web products cannot be used alone, which has the disadvantage of being difficult to use.

In addition, in the case of sound-absorbing materials manufactured by the conventional melt-blown method, single components or fibers with small differences in fiber diameter make up the fiber web. However, sound-absorbing materials made by the melt-blown method have a specific frequency range, such as a low frequency band. The sound absorption performance was somewhat insufficient, so it had the disadvantage of being difficult to use in devices or equipment that use frequencies in a specific region. For example, in vehicles equipped with an internal combustion engine, sufficient sound absorption characteristics are shown by the non-woven sound absorbing material manufactured by the melt-blown method, but in electric vehicles equipped with electric motors that generate noise in a low frequency band, the sound absorption performance in that band is low. Since it was measured below this standard, it was difficult to use.

Republic of Korea Patent Registration No. 10-1665895

The present invention was developed to solve the above-mentioned problems, and is a sound-absorbing material for reducing noise in the audible frequency band of a single layer of randomly mixed meltblown fibers and nanofibers that can laminate laminated pads through non-contact processing without pressing processing. To provide a manufacturing apparatus and a sound-absorbing material manufactured thereby.

In particular, an apparatus for manufacturing a sound-absorbing material for reducing noise in the audible frequency band of a single layer of randomly mixed meltblown fibers and nanofibers that can effectively remove noise in the low-frequency band, and a sound-absorbing material manufactured thereby are provided.

In addition, an apparatus for manufacturing a sound-absorbing material for reducing noise in the audible frequency band of a single layer of randomly mixed meltblown fibers and nanofibers, which can prevent the sound-absorbing characteristics of the sound-absorbing material from deteriorating during processing, and a sound-absorbing material manufactured thereby are provided. It is done.

In addition, the present invention can remove noise generated from vehicles so that it can be used as a sound-absorbing material for vehicles, and in particular, can effectively remove noise caused by motors that generate noise in the low-frequency band, so that it can be used as a sound-absorbing material for electric vehicles. An apparatus for manufacturing a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which two-blown fibers and nanofibers are randomly mixed, and a sound-absorbing material manufactured thereby are provided.

In order to achieve the above-described object, the apparatus for producing a sound-absorbing material for reducing noise in the audible frequency band of a single layer of randomly mixed meltblown fibers and nanofibers of the present invention includes a base made of foam or non-woven material with a predetermined thickness. sound absorbing pad; A hybrid sound-absorbing pad made of a non-woven material that is made of a thickness thinner than the thickness of the base sound-absorbing pad, where microfibers and nanofibers are randomly mixed by spinning to form a single layer, and is bonded to the base sound-absorbing pad in a laminated state; And a fastener for attaching and fixing the hybrid sound-absorbing pad to the base sound-absorbing pad in a permeable manner. It includes a thermoplastic melt-type adhesive of a thin film in which the base sound-absorbing pad, the fastener, and the hybrid sound-absorbing pad are sequentially stacked, and the fastener has a permeable structure. A porous pedestal on which a sound-absorbing material for reducing noise in the audible frequency band, characterized in that it is composed of a material, is placed; It includes a heater that provides heat for melting the adhesive material provided on the fastener on one side of the sound-absorbing material seated on the pedestal, and the base sound-absorbing pad and hybrid sound-absorbing pad of the sound-absorbing material are formed by the adhesive material provided on the fastener melted by the heat of the heater. Put them together.

And, the pedestal is composed of a mesh conveyor belt that moves the sound-absorbing material and is circulated by the drive motor of the conveyor.

In addition, the heater includes a heat source that radiates heat for melting the adhesive material; A blower that blows heat from a heat source to a sound-absorbing material; And a guide chamber that isolates the hot air blown from the blower and guides it in a diffused state to one side of the sound-absorbing material.

In addition, it may further include a suction that absorbs the heat of the heater along with air from the other side of the sound-absorbing material and transmits the heat in the thickness direction of the sound-absorbing material. The suction is installed on the other side of the sound-absorbing material to collect hot air penetrating the sound-absorbing material. collector; and an intake fan that provides negative pressure to the collector.

On the other hand, it is manufactured by the above-described manufacturing device, and is formed on one side of the base sound-absorbing pad made of foam or non-woven material with a predetermined thickness, with a thickness smaller than the thickness of the base sound-absorbing pad, and the microfibers and nanofibers are spun. A hybrid sound-absorbing pad made of non-woven fabric that is randomly mixed to form a single layer and bonded to the base sound-absorbing pad in a laminated state is a sound-absorbing material that is integrally laminated by a thin film-type fastener having a plastic melt-type adhesive material with a breathable structure. provided.

Here, the fastener is interposed between the hybrid sound-absorbing pad and the base sound-absorbing pad so that the hybrid sound-absorbing pad and the base sound-absorbing pad are in close contact with each other on both sides, and the hot melt that forms the adhesive material is meltably applied to both sides, so that the hybrid is bonded to both sides through the hot melt. As the sound-absorbing pad and the base sound-absorbing pad are attached, the hybrid sound-absorbing pad is attached to the base sound-absorbing pad, and is composed of a thin film of hot melt non-woven fabric that ventilates the hybrid sound-absorbing pad and the base sound-absorbing pad.

As described above, the present invention can laminate laminated pads through non-contact processing without compression processing through hot melt thermal fusion, thereby preventing a decrease in sound absorption characteristics during processing.

In addition, since the present invention contains a mixture of micro-diameter meltblown fibers and nano-diameter nanofibers, noise in the low frequency band caused by the nanofibers can be effectively removed. That is, according to the present invention, the sound absorption characteristics in the low-frequency and high-frequency regions are complementary to each other due to the structure of combining the base sound-absorbing pad with excellent sound-absorbing characteristics of high-frequency noise and the hybrid sound-absorbing pad with excellent sound-absorbing characteristics of low-frequency noise. It can be.

In addition, according to the present invention, by combining the base sound-absorbing pad and the hybrid sound-absorbing pad through a fastener to form a single sound-absorbing material, it is possible to overcome the difficulties in handling and post-processing of the nanofiber composite hybrid sound-absorbing pad. In addition, according to the present invention, since the nanofibers are dispersed inside the hybrid sound-absorbing pad and are not exposed on the surface, processing work is easy during post-processing such as lamination, bending, or cutting, and damage to the nanofibers during post-processing is prevented. It can be minimized.

In particular, according to the present invention, a base sound-absorbing pad and a hybrid sound-absorbing pad made of foam or non-woven material with a predetermined thickness and a fastener with a ventilated structure are laminated, so that when heat is applied during manufacturing, heat is applied to the laminate. As this can pass through, the thermal melting of the fastener interposed between the base sound-absorbing pad and the hybrid sound-absorbing pad occurs smoothly, thereby bonding the base sound-absorbing pad and the hybrid sound-absorbing pad. By using a low-weight hot melt non-woven fabric, the base sound-absorbing pad And it improves sound absorption performance by preventing it from affecting the processing shape of the hybrid sound absorption pad.

In addition, according to the present invention, instead of the existing heat-compression lamination process, which reduces the sound-absorbing characteristics, the base sound-absorbing pad and the hybrid sound-absorbing pad are laminated by hot air fusion using a fastener made of hot melt, so that the sound-absorbing characteristics can be prevented from deteriorating. .

Moreover, according to the present invention, the overall thickness of the sound-absorbing material can be provided at a desired level by adjusting the thickness of the base sound-absorbing pad, which is easy to process.

In addition, according to the present invention, PVA, a water-based polymer, is cross-linked during the hot melt melting process through hot air heating, so the molecular structure of the polymer is changed through the cross-linking reaction and the shape stability that maintains the shape of the nanofiber against moisture exposure is achieved. can increase.

In addition, when hot air is heated, the hot air is sucked in from the lower side of the base sound-absorbing pad and the hybrid sound-absorbing pad, thereby quickly circulating the movement of heat, allowing the hot air to pass through the laminated pad intact, and a cross-linking reaction occurs in the process of passing the hot air. It can proceed smoothly.

In addition, since the heat applied to the laminated pad can completely pass through and be discharged, the generation of carbide in the laminated pad due to high temperature can be prevented.

Figure 1 is a perspective view showing a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers are randomly mixed according to the present invention;
Figure 2 is a cross-sectional view showing the sound absorbing material of Figure 1;
Figure 3 is an SEM image of the fiber web of a base sound-absorbing pad with a weight of 80 g / ㎡ made of meltblown microfibers;
Figure 4 is an SEM image of the fiber web of a hybrid sound-absorbing pad with a weight of 80 g / ㎡ mixed with electrospun PVA nanofibers and meltblown microfibers;
Figure 5 is an SEM image of the fiber web of a nanofiber pad made of electrospun PVA nanofibers;
Figure 6 is a cross-sectional view showing a single-layer sound-absorbing material for reducing noise in the audible frequency band in which meltblown fibers and nanofibers are randomly mixed according to another embodiment of the present invention;
Figure 7 is a schematic diagram showing the overall configuration of a manufacturing apparatus for a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers are randomly mixed according to the present invention;
Figure 8 is a partial perspective view schematically showing part of the manufacturing apparatus of Figure 7;
Figure 9 is a flow chart showing a method of manufacturing a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers are randomly mixed according to the present invention;
Figure 10 is a flow chart showing a method of manufacturing a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers are randomly mixed according to the present invention;
Figure 11 is a graph image showing the results of cross-linking evaluation measurement, which is a measurement of water-insoluble items of nanofiber PVA; and
Figures 12 to 16 show graph images showing the sound absorption characteristic measurement results of alpha cabin equipment for sound absorption materials according to each Example and Comparative Example.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms.

Hereinafter, the technical features of the present invention will be described in detail with reference to the attached drawings.

Figures 1 and 2 show a single-layer sound-absorbing material for reducing noise in the audible frequency band in which meltblown fibers and nanofibers are randomly mixed according to the present invention.

The sound-absorbing material for reducing noise in the audible frequency band of a single layer in which melt-blown fibers and nanofibers are randomly mixed according to an embodiment of the present invention includes a base sound-absorbing pad (1) and a hybrid as shown in Figures 1 and 2. Includes a sound-absorbing pad (2) and a fastener (3).

The base sound-absorbing pad 1 may be formed of a foam material or non-woven material having a predetermined thickness. For example, the base sound-absorbing pad 1 may be formed of a porous foam manufactured by foam molding or a non-woven fabric manufactured by melt-blown spinning. In an embodiment of the present invention, it is manufactured by melt-blown spinning. It should be explained that non-woven fabric was used. According to this embodiment, the base sound-absorbing pad 1 may be formed of a non-woven material made of polymer fibers, such as PP (Poly Propylene), PE (Polyethylene), PET (Polyethylene Terephthalate), Nylon (Nylon), or PLA (Poly). Staple fibers are manufactured by melting polymers such as Lactic Acid and spinning them by extrusion and injection through a nozzle, or by melting these polymers and extruding and spinning them through a nozzle. It can be manufactured using various nonwoven fabric manufacturing methods such as the Laid method or Needle Punching method. Unlike the above-described base sound-absorbing pad (1), it may be composed of porous foam formed with porous or microporous. Such porous foam can be manufactured from synthetic resins or polymers such as urethane or EVA, for example.

Here, the spinning solution used to manufacture the base sound-absorbing pad 1 using meltblown spinning, airlaid or needle punching methods can be used without limitation as long as it is a polymer resin. Such polymer resins include, for example, any one selected from the group consisting of polypropylene, polyethylene, polyethylene terephthalate, polypropylene copolymer, nylon, polylactic acid, polyester, polyurethane, polyacrylonitrile, polyolefin, pitch, and cellulose. It could be more than that.

The base sound-absorbing pad (1) is made of micro-sized fibers, and preferably has a diameter of 1 to 15㎛. According to an embodiment of the present invention, the size of the fibers forming the base sound-absorbing pad 1 may be formed to have an average size of 3㎛, and as small as 1㎛. The base sound-absorbing pad (1) may have a weight of 80 to 1,000 g/m2.

The hybrid sound-absorbing pad (2) forms a single layer by randomly mixing microfibers and nanofibers. In other words, the hybrid sound-absorbing pad (2) is a structure in which micro-diameter microfibers manufactured by the melt-blown method and nano-diameter nanofibers manufactured by the electrospinning method are randomly mixed, and the microfibers are discharged by the melt-blowing method. And as the nanofibers discharged by electrospinning are mixed and collected in the collector, they are formed in the form of a non-woven sheet with a composite fiber structure layer. In other words, the hybrid sound-absorbing pad 2 may be made of a non-woven fabric of mixed fibers manufactured by mixing two types of spinning solutions, and the sound-absorbing properties are improved because microfibers that are advantageous for high-frequency sound-absorbing properties and nanofibers that are advantageous in low-frequency sound-absorbing properties are mixed. It can be.

Here, the spinning solution used to manufacture the hybrid sound-absorbing pad (2) is a spinning solution for electrospinning for nanofiber formation and a melt blown spinning solution for microfiber formation. Two spinning solutions can be used, nano Spinning solutions for electrospinning to form fibers include, for example, polypropylene (PP) resin, polyethylene terephthalate (PET) resin, polyvinylidene fluoride (PVdF) resin, polyvinylacetate (PVAc) resin, and polymethyl methacrylate ( PMMA) resin, polyacrylonitrile (PAN) resin, polyurethane (PUR) resin, polybutylene terephthalate (PBT) resin, polyvinyl butyral resin, polyvinyl chloride (PVC) resin, polyolefin resin, poly Lactic acid (PLA) resin, polyethylene naphthalate (PEN) resin, polyamide (PA) resin, polyvinyl alcohol (PVA) resin, polyethyleneimide (PEI) resin, pitch resin, polycarprolactone (PCL) resin, poly It may include any one or more selected from the group consisting of lactic acid glycolic acid (PLGA) resin, silk solution, cellulose solution, and chitosan solution. Another melt blown spinning solution may be the polymer resin solution used to manufacture the base sound-absorbing pad (1) described above.

On the other hand, the hybrid sound-absorbing pad 2 can be manufactured by electrospinning and meltblown spinning as described above. Among these, in the case of a spinning solution for electrospinning to form nanofibers, an aqueous solvent can be used together. Organic solvents such as dimethylformamide (DMF) may be used, but since there are disadvantages that remain even after performing a multi-step solvent removal process, it is preferable to use an aqueous solvent. As an example, polyvinyl alcohol (PVA) can be used. This is a solution mixing process to produce nanofibers using a 20% PVA aqueous solution. Water and PVA are weighed according to the selected concentration in the concentration range of 15 to 30%, then placed in a stirring tank and boiled at a temperature of 80°C for 4 minutes. The solution is prepared by stirring for more than an hour. At this time, PVA can be used as a raw material selected with a degree of saponification in the range of 70% to 99%. Then, the viscosity of the prepared solution is evaluated and used, and a solution having a viscosity value of 1,000 to 5,000 cP can be used. At this time, if the viscosity is lower than this range, nanofibers are not formed smoothly, and if the viscosity is higher than this range, the solution supply is not smooth, so it is preferable to select it within an appropriate range. Contrary to the foregoing, other solvents may be used instead of the PVA solvent.

In this embodiment, the hybrid sound-absorbing pad (2) uses PP or PET as a raw material, and has a spinning temperature of 280°C, a discharge amount of 100g/min, a side air of 6CMM, a distance between the nozzle and the collector of 890mm, and a line speed of 1.6m/min. Conditional melt blown method, PVA is used as a raw material, Micro-sized fibers and nano-sized fibers are mixed by electrospinning under the conditions of 1g/min discharge rate (regulator: 6kgf/㎠), 200LPM side air, 500mm distance between nozzle and melt blown spinning, and 45KV high voltage. It can be formed, and preferably nanofibers with a diameter of 100 to 900 nm and microfibers with a diameter of 1 to 15 ㎛ are mixed. According to an embodiment of the present invention, the size of the fibers forming the hybrid sound-absorbing pad 2 may be formed to have an average size of 2.5㎛, and as small as 900㎚.

This hybrid sound-absorbing pad (2) is formed to have a thickness thinner than the total thickness of the base sound-absorbing pad (1). The thickness of the hybrid sound-absorbing pad (2) may be, for example, 5 to 25% of the total thickness of the base sound-absorbing pad (1).

The hybrid sound-absorbing pad (2) may have a weight of 80 g/m2 and may be coupled to the base sound-absorbing pad (1) in a laminated state.

The fastener (3) is provided between the base sound-absorbing pad (1) and the hybrid sound-absorbing pad (2). That is, the base sound-absorbing pad (1), the fastener (3), and the hybrid sound-absorbing pad (2) are sequentially stacked. This fastener (3) attaches and secures the hybrid sound-absorbing pad (2) to the base sound-absorbing pad (1) in a ventilated manner. Here, the fastener (3) is interposed between the hybrid sound-absorbing pad (2) and the base sound-absorbing pad (1), and the hybrid sound-absorbing pad (2) and the base sound-absorbing pad (1) are in close contact with each other on both sides, and hot melt adhesive is applied on both sides. It is applied in a meltable manner, and the hybrid sound-absorbing pad (2) and the base sound-absorbing pad (1) are attached on both sides through a hot melt adhesive, thereby attaching the hybrid sound-absorbing pad (2) to the base sound-absorbing pad (1). The fastener (3) may be made of a thin film of hot melt non-woven fabric that ventilates the hybrid sound-absorbing pad (2) and the base sound-absorbing pad (1). Hot melt nonwoven fabric is a commonly used thin film hot melt nonwoven fabric. Therefore, since it can be easily understood by those skilled in the art, detailed description is omitted.

This fastener 3 may be made of hot melt nonwoven fabric with a weight of 1.5 to 5.0 g/m2. At this time, when the fastener (3) is composed of a weight of 1.5 g/m2 or less, there is a problem that the adhesive properties are lowered, and when the fastener (3) is composed of a weight of 5.0 g/m2 or more, it does not directly affect the sound absorbing characteristics of the sound absorbing material, but increases the amount used. Since there is a problem of increased production costs, it is preferable to use it within an appropriate weight, and as an example, it can be provided in a low weight of 3g/m2.

The fastener (3) is heat-sealed by a manufacturing apparatus or manufacturing method of a single-layer sound-absorbing material for noise reduction in the audible frequency band in which melt-blown fibers and nanofibers are randomly mixed, which will be described later, and is heat-sealed to the base sound-absorbing pad (1) and the hybrid sound-absorbing pad. (2) can be laminated. That is, the sound-absorbing material of the present invention can be provided as a single sound-absorbing material by combining the base sound-absorbing pad (1) and the hybrid sound-absorbing pad (2) while the fastener (3) is melted.

The sound-absorbing material for noise reduction in the audible frequency band of a single layer composed of a random mixture of meltblown fibers and nanofibers of the present invention constructed in this way includes a base sound-absorbing pad (1) with excellent sound-absorbing characteristics of high-frequency noise, and sound absorption of low-frequency noise. Due to the structure combining the hybrid sound-absorbing pads (2) with excellent characteristics, the sound-absorbing characteristics in the low-frequency region and high-frequency region can be improved in a complementary manner.

In addition, the sound-absorbing material for reducing noise in the audible frequency band of a single layer in which melt-blown fibers and nanofibers of the present invention are randomly mixed is formed by attaching the base sound-absorbing pad (1) and the hybrid sound-absorbing pad (2) through the fastener (3). By combining them to form a single member, it is possible to overcome the difficulties in handling and post-processing of the nanofiber composite hybrid sound-absorbing pad (2). In addition, the sound-absorbing material for noise reduction in the audible frequency band of a single layer in which melt-blown fibers and nanofibers of the present invention are randomly mixed is exposed on the surface while the nanofibers are dispersed inside the hybrid sound-absorbing pad 20. Therefore, it is easy to process during post-processing such as lamination, bending or cutting, and damage to nanofibers during post-processing can be minimized.

In particular, the sound-absorbing material for reducing noise in the audible frequency band of a single layer of randomly mixed meltblown fibers and nanofibers of the present invention has a base sound-absorbing pad (1) and a hybrid sound-absorbing pad (2) made of non-woven fabric, and a ventilated structure. The fasteners (3) are stacked, allowing heat to pass through the laminate when heat is applied during manufacturing, so the fasteners (3) interposed between the base sound-absorbing pad (1) and the hybrid sound-absorbing pad (2). As heat melting occurs smoothly, the base sound-absorbing pad (1) and the hybrid sound-absorbing pad (2) are joined together. By using low-weight hot melt non-woven fabric, the processed shapes of the base sound-absorbing pad (1) and hybrid sound-absorbing pad (2) are changed. It improves sound absorption performance by preventing it from affecting the sound.

In addition, the sound-absorbing material for reducing noise in the audible frequency band of a single layer in which melt-blown fibers and nanofibers of the present invention are randomly mixed is a fastener (3) made of hot melt instead of the existing heat-compression lamination process that reduces sound-absorbing characteristics. Since the base sound-absorbing pad (1) and the hybrid sound-absorbing pad (2) are laminated by hot air fusion, it is possible to prevent the sound-absorbing characteristics from deteriorating.

Moreover, the sound-absorbing material for noise reduction in the audible frequency band of a single layer in which meltblown fibers and nanofibers of the present invention are randomly mixed is manufactured by foam molding or meltblown spinning, or staples spun by polymer melting. As the fiber is manufactured through various non-woven fabrication methods such as the air-laid method or needle punching method, the overall thickness of the sound-absorbing material can be provided at the desired level by adjusting the thickness of the base sound-absorbing pad (1), which is relatively easy to process.

In addition, the sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers of the present invention are randomly mixed is crosslinked with PVA, a water-based polymer, during the hot melt melting process through hot air heating, so crosslinking occurs. Through the reaction, the molecular structure of the polymer changes and the shape stability that maintains the shape of the nanofiber against moisture exposure can be increased.

Table 1 below shows the radiation conditions and filter performance of a sound-absorbing material composed of only a single meltblown fiber, and Table 2 shows the noise reduction in the audible frequency band of a single layer in which the meltblown fibers and nanofibers of the present invention are randomly mixed. This table shows the radiation conditions and filter performance of sound absorbing materials.

Sample
Name. spin beam
temperature
(℃) Feeder discharge volume
(g/min) Line Speed
(m/min) g/㎡ Side Air DCD(mm) efficiency(%) Differential pressure (Pa) note Meltblown fiber sound absorbing material 280 100 1.6 80 6CMM,
300℃ 890 37.22 42.5

Sample
Name. radiation
method Feeder discharge volume
(g/min) Line Speed
(m/min) g/㎡ Side Air DCD(mm) efficiency(%) Differential pressure (Pa) spin beam
temperature
(℃) mixed fiber
sound absorbing material Mlet
Blown 100 1.6 80 6CMM,
300℃ 890 64.88 36 280 electricity One - 200LPM 500

Referring to Tables 1 and 2, the mixed weight of nanofibers by electrospinning of the sound-absorbing material for noise reduction in the audible frequency band of a single layer of randomly mixed meltblown fibers and nanofibers of the present invention was not clearly measured. However, in the efficiency (%) category indicating filter performance by mixing meltblown fibers and nanofibers, it was confirmed that it was nearly doubled from the existing 37.22% to 64.88%, which showed that it was effective in sound absorption characteristics. In this regard, Figure 3 is an SEM image of the fiber web of a base sound-absorbing pad with a weight of 80 g/m2 made of melt-blown microfibers, and Figure 4 is an SEM image of the electrospun PVA nanofibers and melt-blown microfibers. This is an SEM image of the fiber web of a hybrid sound-absorbing pad with a weight of 80 g/m2 mixed with blown microfibers, and Figure 5 shows the fiber web of the nanofiber pad made of electrospun PVA nanofibers. This is a diagram showing an SEM image.

Referring to Figure 3, only microfibers with an average diameter of 3㎛ and a minimum of 1㎛ were observed in the fiber web of the base sound-absorbing pad (1) manufactured by the meltblown method.

Referring to Figure 4, microfibers and nanofibers with an average diameter of 2.5㎛ and a minimum of 800㎚ were observed in the fiber web of the hybrid sound-absorbing pad (2) manufactured by meltblown and electrospinning methods.

Referring to Figure 5, it was confirmed that nanofibers with an average diameter of 300 nm and a minimum diameter of 170 nm were observed in the fiber web of the nanofiber pad manufactured by electrospinning.

In this way, nanometer-scale fiber diameters visible to the naked eye were detected in the hybrid sound-absorbing pad (2) manufactured by meltblown and electrospinning methods. Referring again to the above-mentioned Tables 1 and 2, when comparing the base sound-absorbing pad (1) and the hybrid sound-absorbing pad (2), it can be seen that the filter efficiency is increased in the hybrid sound-absorbing pad (2), which is due to the nanofibers. It can be judged by the effect of mixing. The basis for judging these nanofibers is through observation of fine nanofibers and visual confirmation of the nanofibers, as shown in the figure as a result of SEM image analysis.

Although, fibers of 300 nm, which is the fiber diameter size observed in the nanofiber pad (Figure 5), could not be found in the fiber web of the hybrid sound-absorbing pad (2) (Figure 4), melt blown during the mixing process of PVA nanofibers Since the nanofibers penetrate into the fiber and form a layer, it is judged that it is difficult to observe fibers of the corresponding size when observing with SEM on a plane.

Therefore, when the base sound-absorbing pad 1 and the hybrid sound-absorbing pad 2 are joined by the fastener 3, sound absorption performance can be improved.

On the other hand, the sound-absorbing material for noise reduction in the audible frequency band of a single layer in which melt-blown fibers and nanofibers are randomly mixed according to the present invention is, as shown in FIG. 6, a hybrid sound-absorbing pad (2) and a fastener (3) It may further include a second hybrid sound-absorbing pad (4) and a second fastener (5) stacked with the base sound-absorbing pad (1) on the opposite side. That is, the sound-absorbing material according to this embodiment has a structure in which pads of composite fibers are attached to both sides. The sound-absorbing material according to this embodiment has the same configuration as that of the above-described embodiment described with reference to FIGS. 1 and 2. Accordingly, detailed description of the same configuration will be omitted.

Therefore, the sound-absorbing material according to this embodiment has a structure in which hybrid sound-absorbing pads 2 and 4 of composite fibers are laminated to both sides of the base sound-absorbing pad 1 through fasteners 3 and 5, as shown in FIG. 6. Therefore, the sound absorption performance of the composite fiber can be further improved.

Figure 7 is a diagram showing the overall configuration of a manufacturing apparatus for a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers are randomly mixed according to the present invention, and Figure 8 is a diagram showing the overall configuration of the meltblown fiber and nanofiber according to the present invention. This is a partial perspective view schematically showing part of the manufacturing apparatus for a single-layer sound-absorbing material for reducing noise in the audible frequency band, in which raw fibers and nanofibers are randomly mixed.

The apparatus for manufacturing a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers are randomly mixed according to an embodiment of the present invention includes a base sound-absorbing pad made of foam or non-woven material with a predetermined thickness. (1) and is made of a thickness thinner than the thickness of the base sound-absorbing pad (1), and the microfibers and nanofibers are randomly mixed by spinning to form a single layer, and are bonded to the base sound-absorbing pad (1) in a laminated state. It includes a hybrid sound-absorbing pad (2) made of non-woven fabric and a fastener (3) that permeably attaches and secures the hybrid sound-absorbing pad (2) to the base sound-absorbing pad (1), and the base sound-absorbing pad (1) and the fastener (3) ) and a hybrid sound-absorbing pad (2) are sequentially stacked, and the fastener (3) is made of a thin film thermoplastic melt-type adhesive material with a permeable structure. This is for manufacturing a sound-absorbing material for noise reduction in the audible frequency band. As shown in Figure 7, it includes a pedestal 20, a heater 30, and a suction 40 on which the sound-absorbing material 10, which is a laminated pad, is seated.

The stand 20 is for transporting the sound-absorbing material 10 in one direction, and the sound-absorbing material 10, in which the base sound-absorbing pad 1, the fastener 3, and the hybrid sound-absorbing pad 2 are sequentially stacked, is seated. It may be configured as a conveyor that moves the sound-absorbing material 10.

As shown in FIG. 7, the stand 20 includes a drive motor 21, a roller 22, and a conveyor belt 23. That is, the pedestal 20 has rollers 22 rotated by the drive motor 21 disposed on both sides, and a conveyor belt 23 that is wound around the rollers 22 and rotates circularly by the operation of the drive motor 21. It consists of As shown in FIG. 5, the conveyor belt 23 of the pedestal 20 may be provided as a mesh conveyor belt composed of a porous wire mesh on which a plurality of air connectors 23a are formed. The pedestal 20 may be configured to transport the sound-absorbing material 10 at a speed of 0.5 m/min.

The heater 30 is intended to provide heat to the sound-absorbing material 10, and is installed on the upper side of the pedestal 20 on which the sound-absorbing material 10 is transferred. By providing heat to one side of the sound-absorbing material 10, the heater 30 provides heat to the sound-absorbing material 10. ) so that the adhesive contained in it can be melted. As shown in FIG. 7 , the heater 30 includes a heat source 31, a blower 32, and a guide chamber 33.

The heat source 31 is disposed to be spaced apart from the pedestal 20 and radiates heat for melting the adhesive material included in the sound absorbing material 10. The heat source 31 may be composed of a coil or a heating wire, and radiates heat.

The blower 32 may be disposed on the front or rear side of the heat source 31 and blow the heat of the heat source 31 to the sound-absorbing material 10. That is, the blower 32 is disposed on the front side of the heat source 31 and transfers rear heat to the front, or is disposed on the rear side of the heat source 31 and provides wind toward the front to transfer heat as hot air. .

The guide chamber 33 accommodates a heat source 31 and a blower 32 therein. The guide chamber 33 guides the hot air generated by the heat source 31 and the blower 32 so that it is smoothly supplied to the surface of the sound-absorbing material 10 moving on the pedestal 20. This guide chamber 33 is composed of a fixing part 33a where the heat source 31 and the blower 32 are installed, and a diffusion part 33b that is formed to extend radially from the fixing part 33a to spread hot air. You can. The guide chamber 33 guides the hot air generated inside to be smoothly supplied to the entire surface of the sound-absorbing material 10 as it spreads through the diffusion portion 33b.

In this way, the heater 30 generates hot air from the heat source 31 as hot air through the blower 32 and transfers it to the sound absorbing material 10 through the guide chamber 33. The heater 30 may provide hot air set to a temperature of approximately 110°C.

In addition, the heater 30 preferably has a heat fusion section (H) directly facing the sound-absorbing material 10 transferred from the pedestal 20 with a length of 50 cm to 120 cm. The length of the heat fusion section of the heater 30 may be determined by the size of the guide chamber 33 in which the heat source 31 is installed. At this time, when the length of the heat fusion section by the heater 30 is formed shorter than 50 cm, there is a problem in that the bonding by heat fusion of the adhesive material contained in the sound absorbing material 10 is insufficiently achieved, and the heat fusion section of the heat fusion section is insufficient. If the length is longer than 120 cm, there is a problem of carbide being generated in the sound-absorbing material 10 as the hot air applied to the sound-absorbing material 10 is exposed for a long time, so it is preferable to set it within an appropriate length. As an example, the length of the heat fusion section by the heater 30 of the present invention may be 90 cm.

The suction 40 is for absorbing heat applied to the sound-absorbing material 10, and as shown in FIGS. 7 and 8, it is installed on the lower side of the pedestal 20 on which the sound-absorbing material 10 is transferred. The suction 40 absorbs the heat of the heater 30 along with air from the other side of the sound-absorbing material 10, allowing the heat to transmit and move in the thickness direction of the sound-absorbing material 10. in other words. The suction 40 induces hot air provided from the heater 30 to the sound-absorbing material 10 to pass through the sound-absorbing material 10 and apply heat to the sound-absorbing material 10. As shown in FIG. 7, the suction 40 includes a collector 41 and an intake fan 42 installed on the other side of the sound absorbing material 10.

The collector 41 collects hot air from the heater 30 that passes through the sound absorbing material 10. The collector 41 may be installed adjacent to or in close contact with the lower side of the pedestal 20 and may be arranged across the heat fusion section where the heater 30 is installed. Collector 41 collects heat provided by heater 30.

The intake fan 42 is connected to the collector 41 and provides negative pressure to the collector 41 so that the heat provided from the heater 30 is collected through the collector 41.

The hot air collected through the collector 41 is discharged to the outside through the exhaust pipe 43 connected to the outside.

At this time, the suction 40 may be configured to have a length corresponding to the heat fusion section formed by the heater 30. However, unlike this, the suction 40 is cooled to the sound absorbing material 10 that has passed through the heat fusion section by the heater 30. It may be configured to have a length longer than that of the heater 30 to continuously discharge heat.

The configuration of this suction 40 may be composed of a commonly used intake device or heat exhaust device. Therefore, since it can be easily understood by those skilled in the art, detailed description is omitted.

Let us explain the operation of the apparatus for manufacturing a sound-absorbing material for noise reduction in the audible frequency band of a single layer of randomly mixed meltblown fibers and nanofibers according to the present invention configured as described above.

First, the pedestal 20 transports the sound-absorbing material 10 mounted on the conveyor belt 23 in one direction. As an example, the pedestal 20 may transport the sound-absorbing material 10 at a transport speed of 0.5 m/min.

The sound-absorbing material 10 transported by the pedestal 20 passes through a heat fusion section where the heater 30 and the suction 40 are located.

Then, the heater 30 applies hot air to the sound-absorbing material 10. As an example, the heater 30 applies hot air to the surface of the sound absorbing material 10 at a high temperature of 110° C., thereby causing the adhesive material contained in the sound absorbing material 10 to be thermally fused. The heater 30 applies hot air to the sound-absorbing material 10, which is transported at a transport speed of 0.5 m/min by the above-described pedestal 20, for about 100 seconds.

At this time, while the heater 30 applies hot air to the sound-absorbing material 10, the suction 40 absorbs the heat generated by the heater 30 along with air from the lower part of the pedestal 20 in the thickness direction of the sound-absorbing material 10. Allows heat to pass through.

Accordingly, the heated air applied to the surface of the sound-absorbing material 10 easily passes through the sound-absorbing material 10, and the adhesive material of the fastener 3 interposed between the base sound-absorbing pad 1 and the hybrid sound-absorbing pad 2 It melts.

In addition, the suction 40 causes the hybrid sound-absorbing pad 2 on the upper layer of the sound-absorbing material 10 and the base sound-absorbing pad 1 on the lower layer to come into close contact with each other by the differential pressure formed by the intake and exhaust, and the molten fastener 3 in the middle layer It is attached to each of the upper and lower layers so that lamination is achieved.

That is, the base sound-absorbing pad 1 and the hybrid sound-absorbing pad 2 of the sound-absorbing material 10 are joined by the adhesive material of the fastener 3, which is heat-sealed through hot air heating.

Here, the pedestal 20 is configured so that the conveyor belt 23 that moves the sound-absorbing material 10 is mesh-shaped with pores, so that the discharge of hot air by the heater 30 and the suction by the suction 40 are smoothly performed. It can be.

In addition, the heater 30 induces hot air generated internally to be smoothly supplied to the entire surface of the sound absorbing material 10 through the guide chamber 33, allowing the adhesive material of the fastener 3 to be evenly fused, and some By preventing heat from concentrating in the area, carbides can be prevented from being generated in the sound-absorbing material 10.

In addition, the suction 40 is disposed close to the pedestal 20 so that the hot air provided from the heater 30 can be completely discharged through the sound absorbing material 10 transported on the pedestal 20. It can perform an intake operation. .

In addition, the suction 40 induces the heat generated from the heater 30 to smoothly penetrate the sound-absorbing material 10, and as it absorbs the heat of the sound-absorbing material 10, whose temperature has risen due to the heat, after the adhesive material is melted. During the adhesion process, the sound-absorbing material 10 is allowed to cool quickly. In addition, the suction 40 can rapidly circulate heat movement and prevent carbide from being generated in the sound-absorbing material 10 due to high temperature.

In addition, the suction 40 extends beyond the installation section of the heater 30, and can prevent the generation of carbides and a decrease in the cooling rate due to residual heat after the heat supply by the heater 30 is stopped.

Figure 9 is a flow chart schematically showing a manufacturing method using a manufacturing apparatus for a sound-absorbing material for reducing noise in the audible frequency band of a single layer in which meltblown fibers and nanofibers are randomly mixed according to the present invention.

The manufacturing method using a manufacturing apparatus for a single-layer sound-absorbing material for noise reduction in the audible frequency band in which meltblown fibers and nanofibers are randomly mixed according to an embodiment of the present invention is made of a foam material or non-woven material having a predetermined thickness. It is made of a base sound-absorbing pad (1) with a thickness thinner than the thickness of the base sound-absorbing pad (1), and the microfibers and nanofibers are randomly mixed by spinning to form a single layer, and is attached to the base sound-absorbing pad (1). It includes a hybrid sound-absorbing pad (2) made of non-woven fabric that is combined in a laminated state and a fastener (3) that permeably attaches and secures the hybrid sound-absorbing pad (2) to the base sound-absorbing pad (1), and the base sound-absorbing pad (1) A fastener (3) and a hybrid sound-absorbing pad (2) are sequentially stacked, and the fastener (3) is a sound-absorbing material for reducing noise in the audible frequency band, characterized in that it is composed of a thin film thermoplastic melt-type adhesive material with a permeable structure. It is for manufacturing.

To this end, the manufacturing method of manufacturing the sound-absorbing material using the manufacturing apparatus of the sound-absorbing material for noise reduction in the audible frequency band of a single layer in which melt-blown fibers and nanofibers are randomly mixed according to an embodiment of the present invention is shown in Figure 9. As shown, a base sound-absorbing pad placement step (S110) of placing a base sound-absorbing pad made of foam or non-woven fabric with a predetermined thickness on a pedestal, a thin film-type fastener with a meltable adhesive material is laminated on the base sound-absorbing pad. A fastener stacking step (S120), a laminated pad forming step (S130) of forming a laminated pad by laminating a hybrid sound-absorbing pad made of non-woven fabric on a base sound-absorbing pad on which thin film-type fasteners are laminated, and melting the adhesive material of the fastener to form a hybrid sound-absorbing pad as a base. It may include a pad attachment step (S140) of attaching it to a sound-absorbing pad.

In detail, in the base sound-absorbing pad arrangement step (S110), the base sound-absorbing pad 1 made of foam or non-woven fabric having a predetermined thickness is placed on the pedestal 20.

The base sound-absorbing pad 1 placed on the pedestal 20 in the base sound-absorbing pad placement step (S110) may be manufactured using a polymer such as PP, PE, PET, Nylon or PLA, for example, using a PET spinning solution. Thus, it can be produced as a micro-sized fiber by the meltblown manufacturing method, and preferably has a diameter of 1 to 15㎛. For example, the size of the fibers forming the base sound-absorbing pad 1 may have an average size of 3㎛, and as small as 1㎛. Here, the base sound-absorbing pad 1 may have a weight of 400 g/m2. At this time, the pedestal 20 on which the base sound-absorbing pad 1 is placed in the base sound-absorbing pad arrangement step (S110) may be configured with a conveyor belt 23 for movement of the base sound-absorbing pad 1, and the conveyor belt 23 ) can be provided as a mesh conveyor belt composed of porous wire mesh. Additionally, the pedestal 20 may be configured to transport the sound-absorbing material 10 at a speed of 0.5 m/min.

In the thin film fastener stacking step (S120), a thin film fastener (3) having a meltable adhesive material with a breathable structure is stacked on the surface of the base sound-absorbing pad (1).

The adhesive material of the fastener (3) laminated on the base sound-absorbing pad (1) in the thin film fastener lamination step (S120) may be formed of an adhesive material made of a thin film of hot melt nonwoven fabric to which hot melt is meltably applied, and the adhesive material of the hot melt nonwoven fabric It can be supplied as a single layer fastener (3) with a weight ranging from 1.5 to 5.0 g/m2. As an example, the fastener 3 may be formed with a weight of 3 g/m2.

In the laminated pad forming step (S130), a hybrid sound-absorbing pad (2) made of non-woven material is made with a thickness thinner than the thickness of the base sound-absorbing pad (1), and microfibers and nanofibers are randomly mixed by spinning method to form a single layer. ) is laminated on the fastener (3). That is, the base sound-absorbing pad (1), the fastener (3), and the hybrid sound-absorbing pad (2) are sequentially stacked to form a laminated pad.

The hybrid sound-absorbing pad (2) laminated on the fastener (3) in the laminated pad forming step (S130) may be produced as a composite fiber in which microfibers and nanofibers are mixed by a melt blown method and an electrospinning method, preferably Nanofibers with a diameter of 100 to 900 nm and microfibers with a diameter of 1 to 15 ㎛ may be mixed. For example, the size of the fibers forming the hybrid sound-absorbing pad 2 may be 2.5㎛ on average and as small as 900㎚. Here, the hybrid sound-absorbing pad 2 may be formed with a thickness thinner than the total thickness of the base sound-absorbing pad 1, for example, may be formed with a thickness of 5 to 25% of the total thickness of the base sound-absorbing pad 1. . And, the hybrid sound-absorbing pad 2 may have a weight of 80 g/m2.

Additionally, in this embodiment, the laminated hybrid sound-absorbing pad 2 uses PP or PET as a raw material, and has a spinning temperature of 280°C, a discharge rate of 100 g/min, a side air of 6 CMM, a distance between the nozzle and the collector of 890 mm, and a line speed of 1.6. Melt blown method with conditions of m/min, using PVA as raw material, discharge rate of 1g/min (regulator: 6kgf/㎠), side air 200LPM, distance between nozzle and melt blown radiation 500㎜, 45KV A nonwoven fabric in which micro-sized fibers and nano-sized fibers are mixed and formed by electrospinning under high voltage conditions can be used.

The pad attachment step (S140) is performed by the pedestal 20, heater 30, and suction 40.

In the pad attachment step (S140), the hybrid sound-absorbing pad (2) is attached to the base sound-absorbing pad (1) by melting the adhesive material. In the pad attachment step (S140), hot air is supplied through the heater 30 to the laminated pad transported by the pedestal 20 to melt the adhesive material, and heat is absorbed by the suction 40 to ensure smooth heat transfer. , passes through the heater 30 and goes through a cooling process to complete curing of the adhesive material.

Specifically, as shown in FIG. 10, the pad attachment step (S140) includes an adhesive material melting step (S141) in which heat is provided to the laminated pad to melt the adhesive material provided on the fastener and the molten adhesive is melted. It may include a cooling step (S142) of cooling and hardening the material.

In the adhesive material melting step (S141), the sound-absorbing material 10 transported by the pedestal 20 passes through a heat fusion section where the heater 30 is installed, and hot air is provided by the heater 30 while passing through the heat fusion section. The adhesive material is melted and bonded together. That is, the adhesive material melting step (S141) provides heat to the laminated pad to induce melting of the adhesive material.

In the adhesive material melting step (S141), hot air from the heater 30 is provided from the top to the bottom, and heats the surface of the hybrid sound-absorbing pad 2, which is a laminated pad located on the upper side. The adhesive material melting step (S141) can provide hot air set to a temperature of approximately 110°C, and the heated air on the top of the sound absorbing material 10 passes through the sound absorbing material 10 in the direction of movement, causing the fastener 3 located between the pads. melts the adhesive material. The lower base sound-absorbing pad (1) and the upper hybrid sound-absorbing pad (2) are attached to each other by the melted adhesive material and lamination is achieved.

At this time, in the adhesive material melting step (S141), it is preferable that the exposure time by hot air is set between 80 and 130 seconds based on a temperature of 110°C. If this is shorter than 80 seconds, there is a problem that the crosslinking reaction of the laminated pad is not sufficient, causing it to dissolve in moisture, and if it exceeds 130 seconds, the PVA nanofibers may discolor, increasing manufacturing costs and There is a problem of decreased production. In addition, the hot air exposure time may vary depending on the length of the heat fusion section and the transfer speed determined by the size of the heater 30. For the size of the heater 30 with a heat fusion section of 900 mm, it is 80 to 130 seconds. In order to maintain the heat treatment time, the transfer speed of the pedestal 20 is preferably set to a speed of 0.42 to 0.68 m/min. Therefore, according to one embodiment of the present invention, in the adhesive material melting step (S141), hot air by the heater 30 is provided at a temperature of 110°C, and the length of the heater 30 to which the hot air is provided is set to 900 mm. As a result, the transfer speed of the laminated pad by the pedestal 20 is maintained at 0.5 m/min, and hot air can be supplied to the laminated pad for approximately 108 seconds.

In the adhesive material melting step (S141), crosslinking of PVA nanofibers occurs while hot air passes through the lamination pad.

Thereafter, in the cooling step (S142), the molten adhesive material is cooled to ensure hardening. That is, the cooling step (S142) is natural cooling of the sound-absorbing material 10, which has completely passed the heat fusion section by the heater 30 as it is transported in one direction from the pedestal 20. A section is provided, hardening is performed by cooling, and it is formed from a laminated sound-absorbing material (10).

Meanwhile, the pad attaching step (S140) may further include a suction step (S143) of sucking the heat provided to the laminated pad from the lower part of the laminated pad, as shown in FIG. 10.

The suction step (S143) is between the adhesive material melting step (S141) and the cooling step (S142) or It can be performed through the adhesive material melting step (S141) and the cooling step (S142), and the heat provided to the lamination pad from the heater 30 by the suction 40 installed at the bottom of the pedestal 20 is transferred to the lower part of the lamination pad. The heat is sucked in to completely penetrate the sound-absorbing material (10).

In the suction step (S143), the suction flow rate by the suction (40) is such that hot air passes from the hybrid sound-absorbing pad (2), which is the upper part of the laminated pad, to the base sound-absorbing pad (1), which is the lower part, so that uniform heating and heat transfer are achieved. Since the passing flow rate must be 0.8 to 2.0 m/min, the suction flow rate can be set to 6.48 to 16.2 m3/min. At this time, the supply flow rate is 20% more than the suction flow rate for the purpose of creating positive pressure in the chamber. If the suction flow rate is provided at 10 m3/min, the supply flow rate can be provided at 12 m3/min. there is.

In the suction step (S143), the hybrid sound-absorbing pad (2) in the upper layer and the base sound-absorbing pad (1) in the lower layer are brought into close contact with each other by the differential pressure formed by suction and exhaust through the suction (30), and the molten fastener (3) in the middle layer is attached to each of the upper and lower layers to ensure that the laminated pads are joined. That is, in addition to the adhesion of both adjacent pads simply by melting the fastener 3 through hot air, the adhesion action of the hybrid sound-absorbing pad 2 and the base sound-absorbing pad 1 is increased by differential pressure without a pressing process.

In addition, the suction step (S143) allows the heat applied to the laminated pad to completely pass through and be discharged, thereby preventing carbides from being generated in the laminated pad due to high temperature.

Here, during the lamination process performed in the pad attachment step (S140), when the processing temperature, heat treatment time, and hot air circulation structure are satisfied as described above, the desired performance for crosslinking can be obtained.

Figure 11 is a diagram showing the crosslinking evaluation measurement results, which is a measurement of water-insoluble items of nanofiber PVA. The degree of crosslinking is measured by immersing the product in water at 90°C for 1 minute, taking it out, and measuring the change in weight of the nanofibers.

Referring to Figure 11, when heat treating a nanofiber sound-absorbing product, a temperature of 140°C or higher and a product transfer speed of 5 m/min are required to achieve a crosslinking degree of 93% or more.

For this purpose, the present invention provides a low-weight hot melt nonwoven fabric with a network structure weighing 3 g/m2 with a melting point of 94°C, and the processing temperature was set to 110°C. In addition, the transfer speed of the pedestal 20 was set to 0.5 m/min, and the heat treatment time passing through the heat fusion section (H) was increased to 108 seconds to ensure sufficient heat treatment. In addition, the present invention designs positive pressure inside the guide chamber 33 of the heater 30 with a supply flow rate of 12 m3/min and a suction flow rate of 10 m3/min for a hot air circulation structure, so that uncontrolled external fluid is supplied inside. The hot air generated by the heater 30 is circulated evenly while preventing this from happening.

Accordingly, the present invention provides hot air at a lower temperature than the normal PVA crosslinking heat treatment temperature conditions, but crosslinking treatment is performed stably while providing sufficient time, and a crosslinking degree of 93% or more can be achieved.

As such, according to the manufacturing method using the manufacturing apparatus according to the embodiment of the present invention, non-contact lamination processing is performed by fusing and laminated adhesive materials using a hot air heating method. The present invention is advantageous in maintaining the sound-absorbing characteristics of the sound-absorbing material because the laminating process is performed in a non-contact manner without pressing processing.

In other words, in the case of lamination processing by heat compression, the sound absorption characteristics are reduced because the structure of the sound absorbing material is made dense, while the sound absorption characteristics can be improved by lamination processing by hot air fusion without compression processing.

In addition, according to the manufacturing method using the manufacturing device according to the embodiment of the present invention, PVA, which is a water-based polymer, is cross-linked during the heat fusion process, so the molecular structure of the polymer is changed through the cross-linking reaction and the nano-scale forms against exposure to moisture. It is possible to increase the shape stability that maintains the shape of the fiber. At this time, hot air is input from one side and hot air is sucked in and discharged from the other side, so the movement of heat is circulated quickly. The hot air passes through the laminated pad intact, and the crosslinking reaction proceeds smoothly in the process of passing the hot air. You can.

Experiment example

Through each step of FIGS. 9 and 10 described above, a single-layer sound-absorbing material for reducing noise in the audible frequency band in which meltblown fibers and nanofibers were randomly mixed was manufactured. The base sound-absorbing pad of the sound-absorbing material is made of non-woven fabric containing PET melt-blown microfibers with a fiber diameter of 10-40㎛ and weighs 400g/㎡. The hybrid sound-absorbing pad of the sound-absorbing material is made of a non-woven fabric that is a single layer composite of polypropylene melt-blown microfibers with a fiber diameter of 2~5㎛ and PVA electrospun nanofibers with a fiber diameter of 150~400㎚, and weighs 80g/㎡. A sound-absorbing material was prepared by combining such base sound-absorbing pads and hybrid sound-absorbing pads with fasteners using the manufacturing equipment described above, and sound-absorbing properties were compared with existing products using sound-absorbing performance measurement equipment commonly known as Alpha Cabin. .

Table 3 below shows the sound absorption characteristics of the sound absorption material measured through experimental examples. Among the entire measurement range, data from 400 to 4,000 Hz were selectively used. This band is included in the group of areas that are classified when testing human hearing, including the low-frequency band of 400 to 1,000 Hz, the mid-frequency band of 1,000 to 3,150 Hz, and the high-frequency band of 2,000 to 5,000 Hz. , which is included in the audible frequency band.

Frequency Sound Absorption Coefficient Hz Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 400 0.513 0.480 0.000 0.190 0.460 0.410 0.240 450 0.698 0.625 0.000 0.256 0.565 0.480 0.320 500 0.896 0.773 0.030 0.325 0.683 0.550 0.400 565 0.987 0.838 0.070 0.430 0.780 0.625 0.430 630 1.082 0.905 0.120 0.545 0.878 0.700 0.460 715 1.117 0.950 0.152 0.634 0.970 0.770 0.520 800 1.157 1.010 0.184 0.716 1.065 0.840 0.580 900 1.190 1.083 0.186 0.782 1.135 0.950 0.665 1000 1.223 1.170 0.190 0.852 1.200 1.060 0.750 1125 1.211 1.230 0.200 0.942 1.230 1.130 0.790 1250 1.206 1.283 0.202 1.016 1.250 1.200 0.830 1425 1.187 1.240 0.172 1.016 1.250 1.275 0.915 1600 1.173 1.188 0.146 1.016 1.245 1.350 1.000 1800 1.160 1.153 0.130 1.078 1.230 1.270 1.015 2000 1.143 1.123 0.110 1.150 1.220 1.190 1.030 2250 1.163 1.035 0.116 1.190 1.180 1.170 1.015 2500 1.185 0.953 0.120 1.215 1.145 1.150 1.000 2825 1.085 0.908 0.084 1.146 1.105 1.200 1.050 3150 0.989 0.865 0.050 1.100 1.065 1.250 1.100 3575 0.978 0.888 0.030 1.068 1.060 1.220 1.075 4000 0.967 0.917 0.000 1.050 1.040 1.190 1.050

Experimental Example 1 Figure 12 is a graphical image showing the results of measuring the sound absorption characteristics of the alpha cabin equipment for the sound absorption material according to the present invention (Example 1) and a general sound absorption pad that is not laminated (Comparative Example 1).

Referring to Figure 12, it can be seen that the sound-absorbing material according to the present invention (Example 1) shows significantly improved sound-absorbing characteristics across all areas compared to a general sound-absorbing pad that is not laminated (Comparative Example 1). That is, according to the present invention, it can be confirmed that the sound absorption performance is improved in the audible frequency band including the low frequency and high frequency bands by combining the base sound absorption pad and the hybrid sound absorption pad and using them as a single sound absorption material.

Experimental Example 2

Figure 13 is a graphical image showing the results of measuring the sound absorption characteristics of the alpha cabin equipment for the sound absorbing material according to the present invention (Example 1) and the commercial product 3M Thinsulate sound absorbing material (Comparative Example 2).

3M's Thinsulate sound absorbing material (Comparative Example 2) is a non-woven product made of 70% polypropylene MB fiber and 30% PET fiber non-woven fabric with a weight of 350 g/㎡.

Referring to Figure 13, the conventional sound-absorbing material (Comparative Example 2) shows slightly higher sound-absorbing characteristics than the sound-absorbing material of the present invention (Example 1) in some high frequency bands, but is measured significantly lower in the low-frequency band, and the low frequency band It can be seen that the sound absorption performance is somewhat lacking. That is, it can be seen that the sound-absorbing material according to the present invention (Example 1) shows excellent sound-absorbing characteristics in the low frequency band compared to the 3M Thinsulate sound-absorbing material (Comparative Example 2).

Experimental Example 3

Figure 14 is an image graphically showing the results of measuring the sound absorption characteristics of the alpha cabin equipment for the sound absorbing material according to the present invention (Example 1) and the conventional sound absorbing material of Comparative Examples 3 and 4.

The sound-absorbing materials according to Comparative Examples 3 and 4 were made of melt-blown nonwoven fabric with a weight of 330 g/m2. The sound-absorbing materials of Comparative Examples 3 and 4 were composed of non-woven fabrics of the same weight, but were manufactured in a slightly different manner in the weight ratio of the fibers or the manufacturing process.

Referring to Figure 14, the sound absorbing material according to the present invention (Example 1) has superior sound absorption in the low frequency band (400 Hz to 1,000 Hz) and some high frequency bands (2,500 Hz) than the conventional sound absorbing material of Comparative Example 3 and Comparative Example 4. You can see that it shows the characteristics.

Experimental Example 4

Figure 15 is a graphical image showing the results of measuring the sound absorption characteristics of the alpha cabin equipment for the sound absorption material according to the present invention (Example 1) and the conventional sound absorption material (Comparative Example 5).

The sound absorbing material according to Comparative Example 5 is a sound absorbing material made of melt blown nonwoven fabric with a weight of 180 g/m2. The sound-absorbing material of Comparative Example 5 differed from the sound-absorbing material of Comparative Example 4 only in weight.

Referring to Figure 15, the sound-absorbing material according to the present invention (Example 1) is better than the conventional sound-absorbing material of Comparative Example 5 in the range from 400 Hz to 2,825 Hz, that is, from the low frequency band (400 Hz to 1,000 Hz) to some high frequency bands (2,825 Hz). It can be seen that excellent sound absorption characteristics are shown in the section up to.

Experimental Example 5

Figure 16 shows the alpha cabin equipment for the sound-absorbing material according to the present invention (Example 1, Example 2), a general sound-absorbing pad that is not laminated (Comparative Example 1), and a conventional sound-absorbing material (Comparative Examples 2, 3, and 5). This is an image showing the results of measuring sound absorption characteristics in a graph.

Example 2 is the average value (cross-sectional average) of the characteristic values measured for a plurality of sound-absorbing material groups manufactured by adhering the hybrid sound-absorbing pad to one side or the other side of the base sound-absorbing pad in cross-section according to an embodiment of the present invention. It shows.

Referring to Figure 16, it can be seen that the sound-absorbing material of Example 2 according to the present invention showed measurement results in which the overall average value was somewhat lower than that of the sound-absorbing material of Example 1. That is, it can be seen that the sound-absorbing material of Example 2 exhibits different characteristics as the position of the attachment surface of the hybrid sound-absorbing pad with respect to the base sound-absorbing pad is changed.

As a result of the experiment, it was confirmed that the sound absorption characteristics were improved by combining the hybrid sound absorption pad according to the present invention. In other words, it was found that the sound-absorbing material according to the present invention had significantly improved sound-absorbing characteristics compared to a general sound-absorbing pad without a hybrid sound-absorbing pad (Comparative Example 1), and compared to the remaining comparative examples that are conventional commercial products, the sound absorption characteristics were significantly improved in the low frequency band. It was found that high sound absorption characteristics were shown in some high frequency bands.

Ultimately, according to the present invention, the sound absorption characteristics can be improved by combining a hybrid sound absorption pad containing nano-diameter fibers with microfibers, and the sound absorption characteristics can be improved in the overall audible frequency band across the low and high frequency bands. You can.

In particular, according to the present invention, the sound absorption characteristics in the low-frequency and high-frequency regions are complementary to each other due to the structure of the combination of the base sound-absorbing pad with excellent sound-absorbing characteristics of high-frequency noise and the hybrid sound-absorbing pad with excellent sound-absorbing characteristics of low-frequency noise. For example, it is possible to absorb high-frequency noise caused by the engine of a general internal combustion engine vehicle, and at the same time absorb low-frequency noise caused by a motor mounted on a hybrid or electric vehicle. In other words, according to the present invention, it can be used universally in various fields rather than being limited to the use of blocking noise in a specific band.

The above description is merely an illustrative explanation of the technical idea of the present invention, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are for illustrative purposes rather than limiting the technical idea of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments.

1: Base sound-absorbing pad 2: Hybrid sound-absorbing pad
3: Fastener 10: Laminated pad
20: stand 21: drive motor
22: roller 23: conveyor belt
30: heater 31: heat source
32: blower 33: guide chamber
40: Suction 41: Collector
42: intake fan 43: exhaust pipe

Claims (3)

A base sound-absorbing pad made of foam or non-woven material having a predetermined thickness; A hybrid sound-absorbing pad made of non-woven fabric that is bonded to the base sound-absorbing pad in a laminated state and where microfibers and nanofibers are randomly mixed by spinning to form a single layer; And a fastener for fixing the hybrid sound-absorbing pad by attaching it to the base sound-absorbing pad in a ventilated manner, wherein the base sound-absorbing pad, the fastener, and the hybrid sound-absorbing pad are sequentially stacked, and the fastener has a ventilable structure. A mesh conveyor belt on which a sound-absorbing material for noise reduction in the audible frequency band, which is composed of a thin film of thermoplastic melt adhesive material, is seated, and which is installed at the lower part of the sound-absorbing material so that the sound-absorbing material is not compressed, and moves the sound-absorbing material in a mounted state. A porous base composed of and circulated by the drive motor of the conveyor;
A heater disposed on the top of the sound-absorbing material seated on the pedestal and spaced apart in a non-contact state to provide heat for melting the adhesive material provided on the fastener to one side of the sound-absorbing material; and
A suction installed on the lower side of the pedestal absorbs the heat of the heater along with air from the other side of the sound-absorbing material and transmits the heat in the thickness direction of the sound-absorbing material.
The heater is,
a heat source that radiates heat for melting the adhesive material of the fastener;
A blower that blows heat from the heat source to the sound absorbing material; and
A guide chamber consisting of a fixing part on which the blower is installed and a diffusion part extending radially downward from the fixing part and diffusing hot air blown from the blower to guide the hot air to one side of the sound absorbing material in a diffused state; Includes,
The heater provides a supply flow rate 20% more than the suction flow rate of the suction to form a positive pressure inside the guide chamber, so that the passing flow rate of hot air passing through the sound absorbing material is 0.8 to 2.0 m/min,
The base sound-absorbing pad and the hybrid sound-absorbing pad of the sound-absorbing material are laminated by non-contact hot air processing using an adhesive material provided on the fastener that is melted by the heat of the heater, so that the alpha cabin sound absorption coefficient (Sound Absorption Coefficient) of the sound-absorbing material is at a frequency of 400 Hz. It is 0.480~0.513 at a frequency of 500Hz, 0.773~0.896 at a frequency of 800Hz, 1.010~1.157 at a frequency of 800Hz, 1.170~1.223 at a frequency of 1,000Hz, 1.123~1.143 at a frequency of 2,000Hz, and 1.123~1.143 at a frequency of 2,500Hz. 0.953 A sound-absorbing material manufacturing device for noise reduction in the audible frequency band comprising a single-layer hybrid sound-absorbing pad in which melt-blown fibers and nanofibers are randomly mixed to form ~1.185. According to claim 1,
The hybrid sound-absorbing pad is manufactured by a combined spinning method of electrospinning and meltblown spinning, in which fibers of different sizes are mixed, and an aqueous solvent containing 15 to 30% polyvinyl alcohol aqueous solution is used as the electrospinning solution. And
The heater is formed to have a heat fusion section of 50 to 120 cm at a temperature of 110°C, and the sound absorbing material is a single layer of randomly mixed meltblown fibers and nanofibers, characterized in that the crosslinking degree is 93% or more. A sound-absorbing material manufacturing device for noise reduction in the audible frequency band including a hybrid sound-absorbing pad. The method of claim 1, wherein the suction is:
A collector installed on the other side of the sound-absorbing material to collect hot air passing through the sound-absorbing material; and
A sound-absorbing material manufacturing device for noise reduction in the audible frequency band, including a single-layer hybrid sound-absorbing pad in which meltblown fibers and nanofibers are randomly mixed, including an intake fan that provides negative pressure to the collector.