KR20210099699A - Noise absorbent fabric with excellent heat-resistant and formability, and manufacturing method for the same - Google Patents

Abstract

The present invention relates to a noise absorbent material with excellent heat resistance and formability and a manufacturing method thereof and, more specifically, to a noise absorbent material having a structure in which a heat-resistant material manufactured by impregnating a binder in a nonwoven fabric made of heat-resistant fibers is laminated on one surface of a base layer made of a conventional noise absorbent material as a surface layer, and a manufacturing method thereof. According to the present invention, the noise absorbent material provides effects of providing increased sound-absorbing, flame-retardant, heat-shielding, and heat-resistant properties in accordance with those of conventional noise absorbent materials, being applied to a site where a high temperature of 200℃ or higher is maintained by using the surface layer as a contact surface, and forming a desired shape while the binder impregnated into the surface layer is cured. Accordingly, the noise absorbent material can be widely used in industrial fields requiring noise absorbent materials, such as electric appliance fields including air conditioners, refrigerators, washing machines, lawn mowers, and the like, transportation equipment fields such as automobiles, ships, aircraft, and the like, building material fields including wall materials, flooring materials, and the like, etc.

Description

Sound absorbent fabric with excellent heat-resistant and formability, and manufacturing method for the same

The present invention relates to a sound-absorbing material having excellent heat resistance and moldability and a method for manufacturing the same, and more particularly, a heat-resistant material prepared by impregnating a binder in a nonwoven fabric made of heat-resistant fibers on one surface of a base layer made of a conventional sound-absorbing material as a surface layer. By forming a laminated structure, the sound absorption, flame retardancy, heat shielding, and heat resistance are improved compared to conventional sound absorbing materials, and in particular, it is possible to apply to a site where a high temperature of 200° C. or more is maintained by using the surface layer as a contact surface, and the surface layer It relates to a sound absorbing material having the effect of enabling molding into a desired shape during the process of curing the binder impregnated with the binder and a method for manufacturing the same.

As the industry is highly developed, unnecessary noise is generated to humans, and the degree of damage caused by noise is gradually increasing. Accordingly, various noise prevention measures have been proposed. As a part of these noise prevention measures, various studies are being conducted to develop a sound-absorbing material of a new material having a soundproofing, sound-absorbing or sound-insulating function.

Examples of industrial fields requiring sound-absorbing materials include electric appliances such as air conditioners, refrigerators, washing machines, and lawn mowers, transportation equipment fields such as automobiles, ships, and aircraft, or construction materials such as wall materials and flooring materials. In addition, the use of sound absorbing materials is required in various industrial fields. In the case of sound absorbing materials generally applied in industrial fields, in addition to sound absorption, weight reduction, flame retardancy, heat resistance, and heat insulation are additionally required depending on the application purpose. In particular, if it is a sound absorbing material applied to an engine or an exhaust system in which a high temperature of 200° C. or higher is maintained, flame retardancy and heat resistance may be further required. Currently, aramid fibers are attracting attention as a sound-absorbing material with excellent heat resistance.

In addition, for the purpose of imparting functionality such as flame retardancy and water repellency to the sound absorbing material, a number of sound absorbing materials having a structure in which a nonwoven fabric containing aramid fibers and a functional skin material are laminated have been developed.

For example, in Patent Publication No. 10-2007-0033310, sound absorbing material, (published on March 26, 2007), there is a nonwoven layer in which heat-resistant short aramid fibers and polyester thermoplastic short fibers are intertwined, and short aramid fibers A flame retardant sound absorbing material in which a skin layer made of a wet nonwoven fabric is laminated is disclosed.

However, in the prior art, in order to increase the excellent sound absorption to the desired performance, there is a problem in that other performances such as flame retardancy, heat shielding and heat resistance are remarkably deteriorated.

In addition, there is a problem that it is difficult to mold the sound absorbing material into a desired shape in the process of curing.

Patent Publication No. 10-2007-0033310, sound absorbing material, (published on March 26, 2007)

In order to solve the above problems of the prior art, the present inventors have studied for a long time to develop a sound absorbing material excellent in sound absorption, flame retardancy, heat shielding, and heat resistance as a sound absorption material. As a result, a surface layer made of a heat-resistant material is laminated on the surface of a conventional sound-absorbing material, but the binder penetrates into the nonwoven fabric in which the surface layer has irregular ventilation holes due to the complex three-dimensional labyrinth structure, and the ventilation holes are not blocked. To provide a sound absorbing material with a new structure made of a heat-resistant material that is hardened in a form that maintains a three-dimensional shape.

Accordingly, the present invention provides a sound absorbing material that is excellent in sound absorption, flame retardancy, heat shielding, and heat resistance, as well as being able to be molded into a desired shape during the curing process of the binder included in the surface layer.

In addition, the present invention is a sound-absorbing material with excellent heat resistance and moldability by laminating a heat-resistant material manufactured through a drying process of adjusting the binder content after impregnating a nonwoven fabric made of heat-resistant fiber in a binder on one surface of a base layer made of a conventional sound-absorbing material. A method of manufacturing is provided.

In addition, the present invention provides a method for reducing noise by applying the sound absorbing material to a noise inducing device.

In order to solve the above problems, in the present invention, a base layer made of a conventional sound-absorbing material; and a surface layer containing a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight, and a binder positioned on the same layer as the nonwoven fabric to maintain a three-dimensional shape inside the nonwoven fabric; and has a structure in which the surface layer is laminated on one surface of the base layer.

In addition, as an embodiment, a method of manufacturing a sound absorbing material comprises: a) impregnating a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight in a binder solution; b) drying the impregnated nonwoven fabric to form a surface layer; and c) laminating the surface layer on one surface of the base layer made of a conventional sound-absorbing material; includes

In addition, as an embodiment, the noise reduction method of the noise-inducing device includes the steps of: i) checking a three-dimensional structure of the noise-inducing device; ii) manufacturing and molding the sound absorbing material so that some or all of the three-dimensional structure of the device matches; and iii) adjoining the sound absorbing material to the noise inducing device; includes

The sound-absorbing material of the present invention is a nonwoven fabric made of heat-resistant fiber and a heat-resistant material impregnated with a binder is laminated as a surface layer, thereby improving the natural sound absorption, flame retardancy, heat shielding, and heat resistance of the base layer and at the same time improving the three-dimensional effect of the sound-absorbing material by the binder It has the advantage of being able to implement a shape.

In addition, the sound absorbing material of the present invention has the advantage of imparting functionality to the sound absorbing material by additionally including various functional additives in the binder solution impregnated into the nonwoven fabric.

In addition, since the sound absorbing material of the present invention is excellent in flame retardancy, heat shielding and heat resistance in addition to sound absorption, the sound absorbing material is not deformed or modified even when applied to a silencer maintained at a high temperature of 200° C. or higher.

In addition, when a thermosetting resin is used as a binder, the sound absorbing material of the present invention has the advantage that it can be molded into a desired shape during the curing process of the thermosetting resin. That is, in the high-temperature molding process of manufacturing the sound absorbing material, since curing and molding of the thermosetting resin are simultaneously performed, a process simplification effect can be obtained.

In addition, since the sound absorbing material of the present invention uses a heat-resistant fiber as a nonwoven fabric material constituting the surface layer, thermal deformation of the nonwoven fabric due to the reaction heat generated during the thermosetting process does not occur even when a thermosetting resin is used as a binder.

In addition, since the sound-absorbing material of the present invention is used by increasing the content of heat-resistant fibers only in the surface layer, there is an advantage in that the desired heat-resistant effect is sufficiently secured even when a minimum amount of expensive heat-resistant fibers is used.

Therefore, the sound absorbing material of the present invention requires sound insulation, sound absorption or sound insulation in the field of electric appliances such as air conditioners, refrigerators, washing machines, lawn mowers, transportation equipment fields such as automobiles, ships, and aircraft, or construction materials fields such as wall materials and flooring materials. It is useful as a sound-absorbing material in the field of The sound-absorbing material of the present invention is useful as a sound-absorbing material in a noise-inducing device in which a high temperature of 200° C. or higher is maintained. In particular, when the sound absorbing material of the present invention is applied to the automobile field, it is fastened in close contact with a noise-inducing device such as an engine and exhaust system of a vehicle, or installed at a predetermined distance from the noise-induced device, or a part applied to the noise-inducing device It can be molded and applied.

1 is a schematic view showing the cross-sectional structure of the sound-absorbing material of the present invention.
2 is an electron micrograph (x 300) of the nonwoven fabric constituting the surface layer.
3 is a schematic view showing an example in which a sound absorbing material is molded into a component and applied to a noise inducing device of a vehicle.
4 is a schematic diagram illustrating an example in which a sound absorbing material is installed and applied at a predetermined distance from a noise inducing device of a vehicle.
5 is a graph comparing the sound absorption performance of the surface layer according to the density of the nonwoven fabric.
6 is a graph comparing the heat shielding performance of the aluminum heat shielding plate and the sound absorbing material of the present invention.

The present invention described below can apply various transformations and can have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Also, terms such as first, second, etc. may be used to distinguish and describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

In addition, when at least two different embodiments are described in the present application, all or part of the components may be used by merging and mixing with each other even if there is no particular description within the scope not departing from the technical spirit of the present invention. .

The present invention relates to a sound absorbing material having excellent heat resistance and moldability and a method for manufacturing the same. The sound-absorbing material of the present invention improves sound absorption, flame retardancy, heat shielding, and heat resistance by laminating a surface layer made of a specific heat-resistant material on top of a base layer made of a conventional sound-absorbing material, and in particular, using a binder impregnated in the surface layer, the desired three-dimensional It has its superiority in that it can be molded into a shape.

According to one aspect of the present invention, the present invention is a base layer made of a conventional sound-absorbing material; and a surface layer containing a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight, and a binder positioned on the same layer as the nonwoven fabric to maintain a three-dimensional shape inside the nonwoven fabric; Including, characterized in that the sound-absorbing material forming a structure in which the surface layer is laminated on one surface of the base layer.

According to a preferred embodiment of the present invention, the lamination between the base layer and the surface layer is made by an adhesive, heat or pressure.

According to a preferred embodiment of the present invention, the adhesive used for lamination between the base layer and the surface layer is selected from the binder contained in the surface layer, and more preferably, the adhesive is a thermosetting resin.

According to a preferred embodiment of the present invention, the base layer and the surface layer are each composed of a single layer or multiple layers, and the thickness of the base layer is 5 to 50 mm, and the thickness of the surface layer is 0.1 to 5 mm.

According to a preferred embodiment of the present invention, the base layer is a conventional sound-absorbing material made of one or more materials selected from polyethylene terephthalate fiber, polypropylene fiber, polyethylene fiber, polyamide fiber, glass wool, polyurethane fiber, and melamine fiber. it will be done

According to a preferred embodiment of the present invention, the heat-resistant fibers constituting the nonwoven fabric have a limiting oxygen index (LOI) of 25% or more, and a heat-resistant temperature of 150°C or more.

In addition, according to a preferred embodiment of the present invention, the heat-resistant fiber is aramid fiber, polyphenylene sulfide (PPS) fiber, oxidized polyacrylonitrile (OXI-PAN) fiber, polyimide (PI) fiber, polybenzimidazole (PBI) fiber, polybenzoxazole (PBO) fiber, polytetrafluoroethylene (PTFE) fiber, polyketone (PK) fiber, metal fiber, carbon fiber, glass fiber, basalt fiber, silica fiber, and ceramic fiber It is more than one selected type.

In addition, according to a more preferred embodiment of the present invention, the heat-resistant fiber is an aramid fiber.

In addition, according to a preferred embodiment of the present invention, the nonwoven fabric is made of aramid fibers having a fineness of 1 to 15 denier, and is a single layer nonwoven fabric having a thickness of 3 to 20 mm.

Further, according to a preferred embodiment of the present invention, the density of the nonwoven fabric is 100 to 2000 g/m 2 , and more preferably 200 to 1200 g/m 2 .

In addition, according to a preferred embodiment of the present invention, the binder is a thermosetting resin.

In addition, according to a more preferred embodiment of the present invention, the thermosetting resin is an epoxy resin capable of forming a three-dimensional network structure in the internal structure of the nonwoven fabric.

In addition, according to a more preferred embodiment of the present invention, the epoxy resin is bisphenol A diglycidyl ether, bisphenol B diglycidyl ether, bisphenol AD diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S di in glycidyl ether, polyoxypropylene diglycidyl ether, bisphenol A diglycidyl ether polymer, phosphazene diglycidyl ether, bisphenol A novolac epoxy, phenol novolak epoxy resin, and o-cresol novolak epoxy resin It is one or more selected epoxy resins.

The structure of the sound absorbing material according to the present invention will be described in more detail based on FIGS. 1 and 2 as follows.

1 is a schematic cross-sectional structure of a sound absorbing material according to the present invention. According to FIG. 1, the sound-absorbing material according to the present invention has a structure in which a surface layer 2 of a nonwoven fabric impregnated with a binder is uniformly impregnated on one surface of a base layer 1 made of a conventional sound-absorbing material.

The sound-absorbing material of the present invention has technical characteristics in the structure of the surface layer. That is, the surface layer includes a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight, and a binder positioned in the same layer as the nonwoven fabric to maintain a three-dimensional shape inside the nonwoven fabric. Although the thickness of this surface layer is thin compared to the base layer, and the content of heat-resistant fibers relative to the weight of the total fiber material used for manufacturing the sound-absorbing material is extremely small, the surface layer made of the heat-resistant material must be additionally laminated for sound absorption, flame retardancy, Heat shielding and heat resistance are remarkably improved, and the convenience of molding into a desired three-dimensional shape using a binder can also be provided.

The internal structure of the above-described surface layer 2 is described in more detail based on FIG. 2 as follows.

2 is an electron micrograph for confirming the three-dimensional shape of the inside of the nonwoven fabric before and after being impregnated with the binder.

FIG. 2A is an electron microscope photograph confirming the internal structure of the nonwoven fabric before being impregnated with the binder, and it can be confirmed that the heat-resistant fiber yarns cross each other to form irregular ventilation holes. 2 (B) and (C) are electron micrographs after impregnating the binder in the nonwoven fabric, and it can be confirmed that the binder is finely distributed and attached to the heat-resistant fiber yarn as a whole, and when the binder content is increased, the yarn It can be seen that the surface contains a larger amount of binder.

Although there are some differences depending on the manufacturing method of the nonwoven fabric, the fibers are randomly arranged in three dimensions. Therefore, the pore structure inside the nonwoven fabric forms a very complex labyrinth system that is three-dimensionally connected by regular or irregular fiber arrangement, rather than each independent bundle of capillary tubes. That is, in the nonwoven fabric applied to the surface layer, microcavities are irregularly formed by crossing yarns including heat-resistant fibers in a sparse structure.

When the nonwoven fabric is impregnated with the binder, the binder is finely and evenly distributed throughout the surface of the nonwoven yarn including the heat-resistant fiber and remains attached, thereby forming a vent hole having a finer size than that of the nonwoven fabric before impregnation. The formation of finer ventilation holes in the internal structure of the nonwoven fabric means that the resonance of noise is increased, which also means that the sound absorbing and insulating properties are improved. In this case, when the binder used is cured while forming a three-dimensional network structure by itself, more fine ventilation holes can be formed inside the nonwoven fabric, so that sound absorbing and insulating properties can be further improved.

Therefore, in the surface layer, the binder is evenly penetrated into the nonwoven fabric to maintain the original three-dimensional shape of the nonwoven fabric, and additionally, micro ventilators can be formed more by curing the binder. By achieving various noise resonance, the effect of dissipating noise is increased, and the efficiency of dissipation of noise is maximized, resulting in greatly improved sound absorption performance.

As confirmed through the electron micrograph of FIG. 2, the surface layer has an internal structure in which the binder is evenly dispersed and distributed on the surface of the heat-resistant fiber yarn constituting the nonwoven fabric.

The surface layer having such an internal structure will be described in more detail focusing on each component as follows.

Heat-resistant fiber is used as the main fiber constituting the non-woven fabric. Heat-resistant fibers can be applied to any material with excellent durability that can withstand high-temperature and ultra-high temperature conditions. Specifically, heat-resistant fibers have a limiting oxygen index (LOI) of 25% or more and a heat-resistant temperature of 150°C or more. Preferably, as the heat-resistant fiber, a limiting oxygen index (LOI) of 25 to 80% and a heat resistance temperature of 150 to 300°C are used. Particularly preferably, as the heat-resistant fiber, a limiting oxygen index (LOI) of 25 to 70% and a heat resistance temperature of 200 to 1000°C are used. In addition, the heat-resistant fiber has a fineness of 1 to 15 denier, preferably 1 to 6 denier, and the length of the yarn is 20 to 100 mm, preferably 40 to 80 mm.

As the heat-resistant fiber, a 'super fiber' commonly referred to in the art may be used. Super fiber is specifically aramid fiber, polyphenylenesulfide (PPS) fiber, oxidized polyacrylonitrile (OXI-PAN) fiber, polyimide (PI) fiber, polybenzimidazole (PBI) fiber, polybenzoxazole At least one selected from (PBO) fiber, polytetrafluoroethylene (PTFE) fiber, polyketone (PK) fiber, metal fiber, carbon fiber, glass fiber, basalt fiber, silica fiber, ceramic fiber, and the like may be included.

In the present invention, preferably, aramid fibers are used as heat-resistant fibers. Specifically, in the present invention, meta-aramid, para-aramid, or a mixture thereof may be used as heat-resistant fibers. In the present invention, the aramid fiber used as the yarn of the nonwoven fabric has a fineness of 1 to 15 denier, preferably 1 to 6 denier. The length of the yarn is preferably 20 to 100 mm, preferably 40 to 80 mm, but if the length of the yarn is too short, it is difficult to entangle the yarn during needle punching, and the binding force of the nonwoven fabric may be weakened. Although the binding force of the nonwoven fabric is excellent, there may be a problem in that yarn transfer is not smooth during carding.

Aramid fibers are aromatic polyamide fibers in which aromatic rings such as benzene rings are bonded to each other by amide groups. To distinguish them from aliphatic polyamides (eg nylon), aromatic polyamide fibers are called 'Aramide'. Aramid fibers are manufactured by aromatic polyamide spinning, and are classified into meta-aramid (m-Aramid) and para-aramid (p-aramid) according to the position of the amide bond bonded to the aromatic ring.

[Formula 1]

[Formula 2]

The meta-aramid represented by Formula 1 (m-Aramid) is isophthaloyl chloride (Isophthaloyl chloride) and meta-phenylene diamine (m-phenylene diamine) dissolved in a dimethylacetamide (DMAc) solvent using dry spinning is manufactured by Meta-aramid has a relatively high elongation at break of 22-40% due to its flexible polymer structure, and has advantages in fiberization because it can be dyed. These meta-aramids are commercially available under the trade names of Nomex™ (Nomex™, DuPont, Inc.), and Conex™ (Teijin, Inc.).

Para-aramid (p-Aramid) represented by Formula 2 is absorbed after dissolving terephthaloyl chloride and para-phenylene diamine in N-methylpyrrolidone (NMP) solvent. Manufactured using radiation. Para-aramid has high strength due to its linear highly oriented molecular structure and is 3 to 7 times higher than that of meta-aramid, so it is used as a reinforcing material or a protective material. In addition, para-aramid has strong chemical resistance, low heat shrinkage, excellent shape stability, high cutting strength, and has flame resistance and self-extinguishing properties. These para-aramids include Kevlar™ (from DuPont), Twaron™ (from Teijin), and Technora.

(Technora™, Teijin) is marketed under the trade name.

The above-mentioned aramid is provided as products such as filament, staple, and yarn, and is a strength reinforcing material (transformer, motor, etc.), insulating material (insulating paper, insulating tape, etc.), heat-resistant fiber ( It is used as a fire-fighting suit, fire gloves, etc.) and a high-temperature filter.

In the present invention, as the nonwoven fabric constituting the surface layer, it is characterized in that heat-resistant fibers are used as yarns. However, in order to reduce the cost of the nonwoven fabric, reduce weight, and impart functionality, other fibers are additionally included in the yarns of the heat-resistant fibers. The manufactured nonwoven fabric may also be included in the scope of the present invention. That is, although the nonwoven fabric of the present invention is manufactured by using a heat-resistant fiber as a yarn, it is by no means limited to a non-woven fabric made of only heat-resistant fibers.

If the content of the heat-resistant fiber yarn contained in the nonwoven fabric of the present invention is limited, the heat-resistant fiber may be included in an amount of 30-100 wt%, more preferably 60-100 wt%, based on the weight of the nonwoven fabric.

In addition, the surface layer is impregnated with a binder, and the binder is located in the same layer as the nonwoven fabric and is contained in a form to maintain a three-dimensional shape inside the nonwoven fabric. Any material capable of maintaining a three-dimensional shape inside the nonwoven fabric may be used as the binder material. The 'form that maintains the three-dimensional shape of the inside of the nonwoven fabric' in the above means, when the binder is impregnated in the nonwoven fabric, the binder is attached to the surface of the fiber yarn of the nonwoven fabric in a uniformly distributed state to maintain the irregular vent hole structure or further It means to maintain the original three-dimensional internal shape of the nonwoven fabric by forming it.

Generally, a binder refers to a material used for the purpose of adhesion or bonding between two materials, but the binder in the present invention refers to a material impregnated in a nonwoven fabric made of heat-resistant fibers.

As such, various materials may be applied as a binder impregnated into the nonwoven fabric. First, a thermoplastic resin or a thermosetting resin may be considered as a binder material.

Polyamide-based resins typified by thermoplastic resins have crystalline polar groups like aramid fibers typified by heat-resistant fibers. Accordingly, when a thermoplastic binder is impregnated into a nonwoven fabric made of thermoplastic heat-resistant fibers, surface contact is made by crystalline polar groups similar to each other, and a hard boundary layer is formed at these contact portions to partially block the ventilation holes of the nonwoven fabric. That is, when a thermoplastic resin is used as a binder impregnated in a nonwoven fabric made of heat-resistant fibers, the ventilation holes of the nonwoven fabric are partially blocked and the sound absorption performance is reduced. On the other hand, if the vent hole is blocked, it can be expected that the sound insulation performance will normally be improved, but since the blocked noise is not extinguished inside the nonwoven fabric but is transmitted through a different path, impregnating the thermoplastic binder also improves the sound insulation performance. can't expect In addition, when the nonwoven fabric made of inorganic heat-resistant fibers is impregnated with a thermoplastic binder, the adhesive force between them is weak, so a separate adhesive additive must be used.

In contrast, the thermosetting binder is a heterogeneous material having completely different physicochemical properties compared to the thermoplastic heat-resistant fiber. Accordingly, when the thermosetting binder is impregnated into the nonwoven fabric made of the thermoplastic heat resistant fiber, the boundary layer is formed by line contact due to the heterogeneity of the nonwoven fabric, so that the ventilation hole of the nonwoven fabric is present in an open state. That is, if a thermosetting resin is used as a binder impregnated in the nonwoven fabric made of heat resistant fiber, it is possible to maintain the three-dimensional shape of the inside of the nonwoven fabric. Therefore, in the present invention, a thermosetting resin may be preferably used as the binder.

In addition, the thermosetting resin has a property of being cured by light, heat or a curing agent, and a property of not deforming its shape even under high temperature conditions. Therefore, according to the present invention, by configuring the heat-resistant fiber and the thermosetting binder under specific conditions, it is possible to obtain the effect that it is possible to keep the molded shape even under high-temperature conditions after molding. Therefore, when a thermosetting resin is used as a binder impregnated in the nonwoven fabric, it is possible to form a desired shape during the curing process of the resin, and an additional effect of maintaining the molded shape even under high temperature conditions can be expected.

As described above, when a thermosetting resin is used as a binder to impregnate the nonwoven fabric made of heat-resistant fibers, in addition to the effect of maintaining the three-dimensional shape inside the nonwoven fabric, the effect of molding into a desired shape during the curing reaction of the binder resin can also be expected. there is.

More preferably, an epoxy resin may be used as the binder. Epoxy resin is a type of thermosetting resin, and has a characteristic of being cured into a polymer material having a three-dimensional network structure during curing. Therefore, when the epoxy resin penetrates into the internal structure of the nonwoven fabric and hardens, it forms another vent hole by itself due to the formation of the network structure. can be

In addition, if the curing reaction proceeds in the presence of a curing agent, since a more developed three-dimensional network structure can be formed, the sound absorption effect can be further improved. That is, functional groups such as an epoxy group or a hydroxy group in the epoxy resin and an amine group or a carboxylic acid group in the curing agent react with each other to form a cross-linkage through a covalent bond to form a three-dimensional network polymer. At this time, the curing agent not only acts as a catalyst for accelerating the curing reaction, but also participates in the direct reaction and is connected in the molecule of the epoxy resin. Therefore, it is possible to adjust the size and physical properties of the ventilation hole in the selection of the curing agent.

Examples of the epoxy resin include bisphenol A diglycidyl ether, bisphenol B diglycidyl ether, bisphenol AD diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, polyoxypropylene diglycyl. At least one selected from cidyl ether, bisphenol A diglycidyl ether polymer, phosphazene diglycidyl ether, bisphenol A novolac epoxy, phenol novolak epoxy resin, o-cresol novolak epoxy resin, and the like may be used. It is better to use the epoxy resin having an epoxy equivalent in the range of 70 to 400. The reason is that if the epoxy equivalent is too small, the bonding strength between molecules for forming a three-dimensional network structure is low, or the adhesive strength of the heat-resistant fiber is low, which may be a factor to reduce the physical properties of the sound absorbing material. On the other hand, if the epoxy equivalent is too high, the sound absorption may be deteriorated by forming an excessively dense network structure.

In addition, in the present invention, when a thermosetting resin is used as the binder, a curing agent may be included in the binder solution. As the curing agent, it is preferable to use a compound having a functional group that is easily reacted with an epoxy group or a hydroxy group as a functional group bonded to the binder. As the curing agent, an aliphatic amine, an aromatic amine, an acid anhydride, urea, an amide, an imidazole, or the like may be used. Specific examples of the curing agent include diethyltoluene diamine (DETDA), diaminodiphenylsulfone (DDS), boron trifluoride monoethylamine (BF3·MEA), diaminocyclohexane (DACH), methyltetrahydrophthalic anhydride (MTHPA), methyl-5-norbornene-2,3-dicarboxylic acid anhydride (NMA), dicyandiamide (Dicy), at least one selected from 2-ethyl-4-methyl-imidazole may be used. . More preferably, an aliphatic amine-based or amide-based curing agent is used, since they have relatively rich crosslinking properties and excellent chemical and weather resistance. In particular, it is more preferable to use dicyandiamide (Dicy) in consideration of crosslinking properties, flame retardancy, heat resistance, storage stability, processability, and the like. Dicyandiamide (Dicy) has a high melting point of 200° C. or higher, and thus has excellent storage stability even after being mixed with an epoxy resin, thereby securing sufficient working time until curing and molding.

In addition, in the present invention, a catalyst for accelerating curing of the thermosetting resin used as the binder may be used. As the catalyst, at least one selected from urea, dimethyl urea, tetraphenylborate salt of quaternary DBU, quaternary phosphonium bromide, and the like may be used. The catalyst may be used by being included in a solution containing a binder.

In addition, in the present invention, for the purpose of imparting functionality to the sound absorbing material, various additives, for example, a flame retardant, a heat resistance improver, a water repellent, etc. may be used. Since the additive is included in the binder solution and used, it is not necessary to laminate a separate skin material for imparting functionality to the sound absorbing material.

Melamines, phosphates, metal hydroxides, etc. may be used as the flame retardant. Specifically, the flame retardant may be one or more selected from melamine, melamine cyanurate, melamine polyphosphate, phosphazene, ammonium polyphosphate, and the like. More preferably, melamine is used as a flame retardant, which can be expected to have the effect of improving both flame retardancy and heat resistance at the same time.

As the heat resistance improving agent, alumina, silica, talc, clay, glass powder, glass fiber, metal powder, etc. may be used.

As the water repellent, at least one selected from fluorine-based and the like may be used.

In addition, additives commonly used in the art may be selected and used appropriately for the purpose.

As described above, the sound-absorbing material of the present invention has a structure in which a surface layer made of a specific heat-resistant material is laminated on one surface of a base layer made of a conventional sound-absorbing material. In order to laminate the base layer and the surface layer, they may be laminated by adhesion using an adhesive, or may be laminated through heat, pressure, or the like. In the case of lamination using an adhesive, for example, an adhesive may be applied to one surface of the base layer or the surface layer, and the adhesive-coated surface may be used as an adhesive surface to be in contact with each other to be laminated. The adhesive used at this time may be any adhesive as long as it is commonly used in the art. Since the binder used by impregnating the surface layer of the present invention also has adhesive properties, one or more selected from the above binders may be used as an adhesive. In using the binder as an adhesive, it is preferable to use a thermosetting resin because it is expected to exhibit a stronger adhesive effect because it has a property of curing by heat added during molding. It is particularly preferable to use an epoxy resin as the adhesive. In addition, the present invention is not particularly limited in the amount of the adhesive used, and it is possible to appropriately adjust the content within the acceptable content range for interlayer adhesion.

In addition, in constituting the sound absorbing material of the present invention, the base layer and the surface layer may be a single layer or a multilayer, respectively. In the case of a base layer or a surface layer constituting a multi-layered laminate structure, the material of each layer may be the same or a different material. Since the present invention is an invention for the purpose of improving sound absorption, flame retardancy, heat shielding, heat resistance, and moldability by further laminating a surface layer on a conventional sound-absorbing material, there is no particular limitation on the material constituting the base layer, the layer configuration, etc. . That is, if it is a conventional sound-absorbing material is applied as the base layer of the present invention, the desired effect of the present invention can be sufficiently achieved. Common sound-absorbing materials commercialized in the art may be polyethylene terephthalate fibers, polypropylene fibers, polyethylene fibers, polyamide fibers, glass wool, polyurethane fibers, melamine fibers, and the like.

According to another aspect of the present invention, the present invention comprises the steps of: a) impregnating a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight in a binder solution; b) drying the impregnated nonwoven fabric to form a surface layer; and c) laminating the surface layer on one surface of the base layer made of a conventional sound-absorbing material; It is characterized in that the manufacturing method of the sound-absorbing material comprising a.

The manufacturing method of the sound absorbing material according to the present invention will be described in more detail for each step as follows.

Step a) is a step of impregnating a nonwoven fabric made of heat-resistant fibers in a binder solution.

In the present invention, the nonwoven fabric is impregnated with a binder to improve sound absorption and sound insulation properties, and to enable molding into a sound-absorbing material of a desired shape. The binder solution impregnating the nonwoven fabric includes a curing agent, a catalyst, a conventional additive and a solvent in addition to the binder resin.

Binders, curing agents, catalysts, and general additives included in the binder solution are as defined above. In addition, as the solvent used in preparing the binder solution, at least one selected from ketone-based, carbonate-based, acetate-based, cellosolve-based, and the like may be used. The solvent is selected from acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), dimethyl carbonate (DMC), ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, and the like. One or more types may be used.

Specifically, the binder solution used in the present invention preferably comprises 1 to 60% by weight of the binder and the remaining amount of the solvent. In addition to the binder solution used in the present invention, it can be used by including other additives including a curing agent and a catalyst. In this case, the binder solution may include 1 to 60% by weight of the binder, 01 to 10% by weight of the curing agent, 001 to 5% by weight of the catalyst, 1 to 40% by weight of the additive, and the remaining amount of the solvent. More preferably, the binder solution may include 1 to 30% by weight of a binder, 01 to 10% by weight of a curing agent, 001 to 5% by weight of a catalyst, 1 to 30% by weight of a flame retardant as an additive, and 40 to 95% by weight of a solvent. .

The binder solution of the present invention can control the degree of impregnation of the nonwoven fabric by controlling its concentration. If the concentration of the binder solution is too thin, the desired effect of the present invention cannot be obtained because the binder content impregnated into the nonwoven fabric is too thin, and if it is too thick, the nonwoven fabric is hardened and cannot function as a sound absorbing material.

In addition, if the content of the curing agent included in the binder solution is too small, complete curing of the binder cannot be expected, and not only cannot be molded into a desired molded body, but also the effect of improving the mechanical strength of the sound absorbing material may be insufficient. hardened, and storage stability may be poor. In addition, if the content of the catalyst is too small, the degree of accelerating the reaction is insignificant, and if an excessive amount of the catalyst is used, storage stability may be rather poor. In addition, as the additive, one or more selected from additives commonly used in the art, including flame retardants, heat resistance improvers, and water repellents, may be used. These additives may be appropriately adjusted according to the purpose of addition, and if the content is less than the range, the effect of the addition is weak, and if used in excess of the above range, economical efficiency is deteriorated and other side effects may be caused.

Step b) is a step of preparing the surface layer by drying the impregnated nonwoven fabric.

Drying in the present invention consists of a process of removing the solvent by taking out the nonwoven fabric impregnated with the binder solution. In this case, an appropriate temperature and pressure may be given. Specifically, the drying process may include a process of adjusting the binder content in the nonwoven fabric by taking out the impregnated nonwoven fabric and ^{compressing it at a pressure of 1 to 20 kgf/cm 2 .} In addition, the drying process may include a process of evaporating the solvent while taking out the impregnated nonwoven fabric and heating it to a temperature of 70 to 200 ℃.

In addition, the drying process may ^{include a process of sequentially performing a process of taking out the impregnated nonwoven fabric and pressing the impregnated nonwoven fabric at a pressure of 1 to 20 kgf/cm 2} and heating to a temperature of 70 to 200 °C.

Drying of the present invention is a process of controlling the binder content in the nonwoven fabric, and it can be said that it is an important process for controlling the physical properties of the sound absorbing material. That is, the content of the binder included in the nonwoven fabric after drying is an important factor for controlling the size, shape, and distribution of the ventilation holes inside the sound absorbing material, and this is because the sound absorption and mechanical properties of the sound absorbing material can be adjusted.

In the present invention, the final content of the binder included in the nonwoven fabric through the drying process may be adjusted to 1 to 300 parts by weight, more preferably 30 to 150 parts by weight, based on 100 parts by weight of the nonwoven fabric.

Step c) is a step of laminating the surface layer prepared in b) on one surface of the base layer made of a conventional sound-absorbing material.

The lamination may be laminated by adhesion, or may be laminated through heat, pressure, or the like. In the case of lamination using an adhesive, for example, an adhesive may be applied to one surface of the base layer or surface layer, and the adhesive-coated surface may be used as an adhesive surface to be in contact with each other to be laminated.

On the other hand, the present invention includes a method of manufacturing a sound absorbing material further comprising the step (d step) of molding the laminated sound absorbing material at a high temperature after step c).

Specifically, the method for manufacturing a sound absorbing material comprising the step d) includes: a) impregnating a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight in a binder solution; b) drying the impregnated nonwoven fabric to form a surface layer; c) laminating the surface layer on one surface of the base layer made of a conventional sound-absorbing material; and d) molding the sound absorbing material formed by being laminated at a high temperature.

Step d) is a step of molding the sound absorbing material formed by laminating the base layer and the surface layer at a high temperature. The above-described high-temperature molding process is a process in which the curing reaction of the thermosetting binder is also taken into consideration, and the molding temperature is maintained at a temperature of 150 to 300°C, more preferably, a temperature of 170 to 230°C.

On the other hand, the present invention is characterized in that, before step a), the method for manufacturing a sound absorbing material further comprising the step (a-1 step) of forming a nonwoven fabric by a needle punching process using a heat-resistant fiber. For example, the step a-1 is also a step of forming an aramid nonwoven fabric having a thickness of 3 to 20 mm by a needle punching process using heat-resistant fibers of aramid having a fineness of 1 to 15 denier.

The method for manufacturing a sound absorbing material according to the present invention comprising the step a-1) is, for example, a-1) a nonwoven fabric having a thickness of 3 to 20 mm by a needle punching process using a heat-resistant fiber having a fineness of 1 to 15 denier. forming; a) impregnating a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight in a binder solution; b) drying the impregnated nonwoven fabric to form a surface layer; and c) laminating the surface layer on one surface of the base layer made of a conventional sound-absorbing material; may be included.

In addition, the method for manufacturing a sound absorbing material according to the present invention comprising the step a-1) is, for example, a-1) a thickness of 3 to 20 mm by a needle punching process using a heat-resistant fiber having a fineness of 1 to 15 denier. forming a nonwoven fabric; a) impregnating a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight in a binder solution; b) drying the impregnated nonwoven fabric to form a surface layer; c) laminating the surface layer on one surface of the base layer made of a conventional sound-absorbing material; And d) molding the sound absorbing material formed by lamination at a high temperature; may be included.

The step a-1) forming the nonwoven fabric includes a needle punching process using a heat-resistant fiber. The sound absorption may vary depending on the thickness and density of the nonwoven fabric, and it is predicted that the greater the thickness and density of the nonwoven fabric, the greater the sound absorption.

In the present invention, considering the industrial field to which the sound absorbing material is applied, the thickness of the nonwoven fabric is preferably 3 to 20 mm.

The reason is that when the thickness of the nonwoven fabric is less than 3 mm, it is difficult to satisfy the durability and moldability of the sound-absorbing material, and when the thickness exceeds 20 mm, there is a problem in that the productivity is lowered during manufacturing and processing of the fabric and the cost is increased. In addition, the weight of the nonwoven fabric is preferably 100-2000 g/m2, preferably 200-1200 g/m2, more preferably 300-800 g/m2, in consideration of performance and cost aspects.

The aramid nonwoven fabric is sequentially first up-down preneedling (Up-down preneedling), second down-up needling by laminating 2 to 12 layers of 30-100 g/m2 web formed through carding. (Down-up needling) and the third up-down needling (Up-down needling) through the continuous process to control the required thickness, secure the necessary binding force and form a physical bridge for the realization of the necessary properties. At this time, the needle (needle) is a working blade (working blade) of 05 ~ 3 mm, the length of the needle (distance from the crank outside to the point) is 70 ~ 120 mm of barb (Barb) type needle is used. The needle stroke is preferably 30 to 350 times/m 2 .

More preferably, the fineness of the yarn for the nonwoven fabric is 15 to 80 denier, the thickness of the pile forming layer is 6 to 13 mm, the number of needle strokes is 120 to 250 times/m2, and the density of the nonwoven fabric is preferably 300 to 800 g/m2 .

The internal structure of the sound absorbing material manufactured through the manufacturing method as described above can be confirmed through an electron microscope. As confirmed by electron micrographs, ventilation holes having a size of 1 to 100 μm were distributed inside the sound absorbing material of the present invention, and these ventilation holes were regularly or irregularly distributed at intervals of 01 to 500 μm.

According to another aspect of the present invention, the present invention comprises the steps of: i) confirming a three-dimensional structure of a device for causing noise; ii) manufacturing and molding the sound absorbing material so that some or all of the three-dimensional structure of the device matches; and iii) adjoining the sound absorbing material to the noise inducing device; It features a noise reduction method of a noise inducing device comprising a.

In the above, the term "device" means a device that causes noise, including a motor, an engine, and an exhaust system, and the device of the present invention is not limited to the motor, engine, and exhaust system. It can be manufactured and used so that some or all of the three-dimensional structure of the device matches. Since the sound absorbing material of the present invention has the advantage of being able to be molded during the curing process of the binder, the sound absorbing material can be molded and used so that a part or all of the three-dimensional structure of the device matches.

As used herein, the term “adjacent” means to be fastened in close contact with the noise-generating device, installed at a predetermined distance from the noise-induced device, or molded into a part applied to the noise-induced device and applied.

Also, adjoining in the present invention includes further mounting to a member (eg, other sound-absorbing material) coupled to the noise-generating device.

3 and 4 schematically show a representative example in which the sound absorbing material of the present invention is applied to a noise inducing device of a vehicle.

3 is a schematic view showing an example in which a sound absorbing material is molded into parts and applied to a noise inducing device of a vehicle, (A) is a photograph of a sound absorbing material applied to an automobile engine, (B) is a sound absorbing material to a part of the engine of the automobile Here is a picture showing an example of how it was installed.

In addition, FIG. 4 is a schematic view showing an example of installing and applying a sound absorbing material to a noise inducing device of a vehicle, a photograph of a sound absorbing material applied to the lower part of the car body, (B) is a sound absorbing material attached to the lower part of the car body This is an example picture.

As described above, the sound-absorbing material of the present invention has a surface layer of a nonwoven fabric impregnated with a binder, and the binder is impregnated so that the internal three-dimensional shape of the nonwoven fabric is maintained. It exhibits the effect of improving sound absorption, flame retardancy, heat shielding, and heat resistance, and in particular, even when directly applied to a silencer maintained at a high temperature of 200° C. or higher, the original sound absorbing and insulating effect can be exhibited without deformation of the molded body.

On the other hand, the embodiments disclosed in the drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

1: Base layer made of a conventional sound-absorbing material
2: Surface layer of non-woven fabric impregnated with binder
3: adhesive layer

Claims (8)

a base layer made of a conventional sound-absorbing material; and
It contains a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight, and a binder located in the same layer as the nonwoven fabric to maintain a three-dimensional shape inside the nonwoven fabric,
a surface layer in which the binder is attached in a distributed state to the surface of the fiber yarn of the nonwoven fabric to maintain or further form a notification hole structure of the nonwoven fabric; including,
The surface layer is laminated on one surface of the base layer,
Lamination between the base layer and the surface layer is made by an adhesive, heat or pressure, which is a thermosetting resin selected from binders contained in the surface layer,
The base layer and the surface layer are each a sound absorbing material composed of a single layer or multiple layers. According to claim 1,
The base layer is a sound absorbing material made of a conventional sound absorbing material made of at least one material selected from polyethylene terephthalate fiber, polypropylene fiber, polyethylene fiber, polyamide fiber, glass wool, polyurethane fiber, and melamine fiber. According to claim 1,
The nonwoven fabric constituting the surface layer is a sound absorbing material having a density of 100 to 2000 g/m 2 . According to claim 1,
The heat-resistant fibers constituting the nonwoven fabric have a limiting oxygen index (LOI) of 25% or more and a heat-resistant temperature of 150°C or more. 5. The method of claim 4,
The heat-resistant fiber is aramid fiber, polyphenylene sulfide (PPS) fiber, oxidized polyacrylonitrile (OXI-PAN) fiber, polyimide (PI) fiber, polybenzimidazole (PBI) fiber, polybenzoxazole ( At least one sound absorbing material selected from PBO) fiber, polytetrafluoroethylene (PTFE) fiber, polyketone (PK) fiber, metal fiber, carbon fiber, glass fiber, basalt fiber, silica fiber, and ceramic fiber. a) impregnating a nonwoven fabric having a heat-resistant fiber content of 30 to 100% by weight in a binder solution;
b) drying the impregnated nonwoven fabric to form a surface layer;
c) laminating the surface layer on one surface of the base layer made of a conventional sound-absorbing material; and
d) forming the sound-absorbing material formed by being laminated at a high temperature; and, in the impregnating step, the binder is attached in a distributed state to the surface of the fiber yarn of the non-woven fabric to maintain or further form the notification hole structure of the non-woven fabric. manufacturing method. 7. The method of claim 6,
The drying in step b) is performed at a temperature of 70 to 200° C., and the internal sound absorbing and insulating layer formed by drying contains 1 to 300 parts by weight of a binder based on 100 parts by weight of the nonwoven fabric. i) confirming the three-dimensional structure of the device causing the noise;
ii) manufacturing and molding the sound absorbing material of any one of claims 1 to 12 so that some or all of the three-dimensional structure of the device matches; and
iii) adjoining the sound absorbing material to the noise inducing device;
The device is a noise reduction method of a noise generating device that is a motor, an engine or an exhaust system.

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