KR102566758B1 - Sound absorbing and insulating material for automobile engine encapsulation - Google Patents

Abstract

It relates to a sound-absorbing insulator for automotive engine encapsulation, and is formed in multiple layers including, in detail, a polymer resin layer, a silica airgel/polyurethane composite layer, a composite fiber layer, and an aluminum sheet layer, and can be closely applied to an encapsulation engine. The present invention relates to a sound-absorbing insulating material for encapsulation of an automobile engine, which more efficiently reduces thermal energy and noise emitted to the outside of an engine to exhibit improved insulation and sound-absorbing effects.

Description

Sound absorbing and insulating material for automobile engine encapsulation}

The present invention relates to a sound-absorbing heat insulating material for encapsulation of an automobile engine, which effectively reduces noise and heat energy generated from an automobile engine, exhibits improved insulation and sound absorption, and is characterized in that it can be closely applied to the engine. It relates to sound-absorbing insulation materials for encapsulation.

In general, in the engine room of a vehicle, noise introduced into the engine room from the outside of the vehicle as well as noise caused by the operation of the engine for driving or the operation of the air conditioner are generated. The noise generated in this way is transferred to the interior of the vehicle and acts as a factor deteriorating riding comfort.

Accordingly, a structure surrounding the engine to reduce noise, that is, an engine encapsulation technology is being developed. 1 is a reference diagram for explaining the concept of engine encapsulation. Car body shaped encapsulation is a concept of encapsulating the entire engine room by attaching members to the surface of the vehicle body according to the shape of the vehicle body in the engine room. Mid-field encapsulation is a concept of encapsulation in the middle of the vehicle body and the powertrain in which the engine (including attached exhaust system parts) and transmission are combined. It is a complex encapsulation concept for optimization, and near-field encapsulation is a concept of encapsulation by attaching an encapsulation member directly to the surface of the engine and transmission. Since it is attached, the noise generated by the engine can be absorbed more efficiently.

However, in the case of near-field encapsulation, it is difficult to configure and adhere to the layout due to the various structures and arrangements of the engine, transmission and its accessory parts, and furthermore, the closer to the noise source of the engine, the closer to the heat source. It is possible to maintain its shape even in the sound absorbing material, so the required heat resistance increases due to the function as a sound absorbing material, and the demand for flame retardancy increases due to the risk of fire, so sound absorption as well as heat insulation performance is required.

In addition, when the weight of the encapsulated sound-absorbing insulating material is increased to realize sound-absorbing insulating material performance, there is a problem in that vehicle fuel efficiency decreases due to the increased weight of the vehicle, and there is a limit to the sound-absorbing and insulating performance that can be improved.

Therefore, a sound absorbing heat insulating material including polyurethane foam having sound insulating performance and glass fiber having heat insulating property has been used as a sound absorbing insulating material having light weight while being closely attached to the engine.

Korean Patent Registration No. 10-0238549 (published on January 15, 2000) relates to a method for manufacturing soundproofing and heat insulating materials for automobiles. Polyurethane and glass fibers, each of which have a thin thickness but are molded at a high density, are overlapped, and the top and bottom of these are overlapped. It is disclosed that a nonwoven fabric or aluminum foil, which is a flame retardant material, can be overlapped to block noise and high heat generated from an automobile engine.

However, in the case of glass fiber, it is easily torn due to weak tissue cohesion, and the radiation of glass fiber exposed to the outside during use is very harmful to health and causes industrial pollution. In the case of polyurethane, there are limitations in physical properties and sound absorption, so polyurethane It is difficult to obtain a satisfactory sound absorption and insulation effect only by overlapping with the fiber, and in particular, it is difficult to obtain a satisfactory sound absorption coefficient for air transmission noise, which accounts for the largest portion in the high-pitched range among vehicle noise.

Accordingly, the present invention is to improve these problems and provide a sound-absorbing insulating material for encapsulation of an automobile engine that can be closely applied to an automobile engine.

Korean Patent Registration No. 10-0238549 (2000.01.15. Publication date)

An object of the present invention is to provide a sound-absorbing insulating material for encapsulation of an automobile engine, which can be closely applied to an automobile engine and can more effectively reduce thermal energy and noise emitted to the outside of the engine to exhibit improved insulation and sound absorption effects. .

The present invention is a polymer resin layer made of a polymer resin; a silica airgel/polyurethane composite layer laminated on top of the polymer resin layer; a composite fiber layer laminated on top of the silica airgel/polyurethane composite layer and containing polyamide and glass fibers; and an aluminum sheet layer laminated on top of the composite fiber layer.

In one embodiment, a binder layer may be further included between the respective layers.

In one embodiment, the silica airgel/polyurethane composite has a structure in which silica airgel is bonded to a polyurethane support in the form of a monolith, and the porosity of the silica airgel/polyurethane composite may be 50% or more.

The sound-absorbing insulator for automotive engine encapsulation of the present invention can maintain its shape even in a high-temperature environment, so it can be closely applied to engines that generate high temperatures, thereby more efficiently reducing heat energy and noise emitted to the outside of the engine, thereby reducing consumption in the engine. It shows improved insulation properties and sound absorption performance for heat generation.

In addition, fuel efficiency can be improved due to the improved insulation characteristics according to the present invention.

1 is a reference diagram for explaining the engine encapsulation concept of the present invention.
2 is a diagram illustrating a sound-absorbing heat insulating material for encapsulation of a vehicle engine according to an embodiment of the present invention.
3 is a cross-sectional photograph at high magnification before and after synthesizing silica airgel into polyurethane foam according to an embodiment of the present invention.
Figure 4 is a graph showing the sound absorption coefficient of Example 1 and Comparative Example 1 according to an embodiment of the present invention.
5 is a graph showing CO ₂ emissions and engine revolutions in Example 1 and Comparative Example 1 according to an embodiment of the present invention.
6 is a photograph of mounting the engine encapsulation sound absorbing heat insulating material according to an embodiment of the present invention to an automobile engine.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, nomenclature used herein is well known and commonly used in the art.

When it is said that a certain part "includes" a certain component throughout this specification, it means that it may further include other components, not excluding other components unless otherwise stated.

The present invention is a polymer resin layer made of a polymer resin in one aspect; a silica airgel/polyurethane composite layer laminated on top of the polymer resin layer; a composite fiber layer laminated on top of the silica airgel/polyurethane composite layer and containing polyamide and glass fibers; and an aluminum sheet layer laminated on top of the composite fiber layer.

2 is a diagram illustrating an embodiment of a sound-absorbing heat insulating material for encapsulation of a vehicle engine according to the present invention, and the present invention will be described in detail with reference to this.

In the present invention, the polymer resin layer 10 may be a polymer resin that can generally be used as a sound-absorbing and insulating material for interior automobiles, but is preferably made of a polyester-based nonwoven fabric with an areal density of 50 to 300 g/m ² . . If the areal density is less than 50 g/m ² , product stiffness is reduced below a predetermined range and there is a risk of losing the product protection effect, and in the case of more than 300 g/m ² , weight reduction for fuel efficiency improvement due to an increase in composite weight. because the effect is reduced.

In the present invention, the silica airgel / polyurethane composite layer 30 is a layer laminated on the polymer resin layer, and the silica airgel / polyurethane composite uses foamed polyurethane as a support and the foamed polyurethane pore wall surface ( Silica airgel is synthesized on the surface and in the pores of the cell walls) to have a porosity of 50% or more, preferably 80% or more, thereby strengthening the low mechanical properties of the silica airgel and supplementing the low insulation properties of polyurethane.

At this time, the density of the polyurethane foam is 10 to 100 kg/m ³ . If the density of the foamed urethane is less than 10 kg / m ³ , supplementation of low mechanical properties of silica airgel through the introduction of polyurethane foam is not sufficient, and if it exceeds 100 kg / m ³ , vehicle fuel efficiency may decrease due to weight increase. Because. In particular, the pores on this foamed urethane include 10 to 90% of open cells.

The pores of the foamed urethane include open cells and closed cells to have elasticity, sound absorption, durability, and heat insulation. Including it at a rate of 90% to improve heat insulation, elasticity and sound absorption. Specifically, if the open cell of the foamed urethane is less than 10%, the area where silica airgel can be synthesized is reduced and the insulation effect is reduced. Since molding is impossible, 10 to 90% of open cells are included.

In addition, the silica airgel of the silica airgel/polyurethane composite layer 30 exhibits a Knudsen diffusion effect as it has a high porosity and a mesoporous pore structure of about 50 nm. The Knudsen diffusion effect refers to gas diffusion, which collectively refers to the case where the probability of gas molecules colliding with the walls constituting the pores is greater than the probability of colliding with each other when gas passes through the pores. Due to this, it shows excellent insulation effect and sound absorption rate.

Furthermore, in the present invention, the silica airgel is contained in an amount of 1 to 100 parts by weight based on 100 parts by weight of polyurethane, and is bonded to the surface and pores of the foamed polyurethane in a monolith form and uniformly distributed in the surface and pores of the foamed urethane, This efficiency can be further improved.

Accordingly, the silica airgel/polyurethane composite layer 30 may improve thermal insulation and sound absorption while reinforcing low mechanical properties of conventional silica airgel and supplementing low thermal insulation characteristics of polyurethane.

The method of forming the silica airgel/polyurethane composite is not limited, but may be prepared by a sol-gel method using acid and base catalysts, specifically, based on 1 mole of the silica precursor based on the molar ratio A mixture consisting of 6 to 30 mol of solvent, 5 to 20 mol of water, 0.001 to 1 mol of acid catalyst, and 0.01 to 5 mol of base catalyst is stirred at room temperature for 1 hour to 24 hours, and then the solution is penetrated into the pores of polyurethane foam. After the condensation reaction, a gel is formed. Thereafter, it is aged in an oven at 30 to 50 degrees Celsius for 10 hours to 3 days in an atmospheric pressure drying process rather than drying using a supercritical fluid, and then dried in a solvent to obtain silica airgel/polyurethane with a porosity of 80% or more through a sol-gel reaction. Manufacture a hybrid sound-absorbing insulation material. In this case, the solvent is at least one selected from methanol, ethanol, isopropyl alcohol, and butanol, and the solvent is included in an amount of 6 to 30 moles based on 1 mole of the silica precursor. When the content of the solvent is less than 6 moles, the volume of the silica airgel is reduced to exhibit low insulation properties, and when it exceeds 30 moles, cracks are generated during the drying process due to the increase in the volume of the gel, resulting in a monolithic monolithic product. because it cannot be manufactured.

The water includes 5 to 20 moles of water based on 1 mole of the silica precursor. This is because when the water content is less than 5 moles, mechanical performance is deteriorated due to a low reaction rate, and when the water content is greater than 20 moles, cracks occur during the drying process due to an increase in the volume of the gel.

The acid catalyst is at least one selected from sulfuric acid, hydrochloric acid, acetic acid and oxalic acid, and is included in an amount of 0.001 to 1 mol based on 1 mol of the silica precursor. This is because when the content of the acid catalyst is less than 0.001 mol, the particle formation rate of the silica precursor is slowed, and when the content of the acid catalyst is greater than 1 mol, the particle size increases and precipitation occurs.

The base catalyst uses ammonia water, and contains 0.01 to 5 moles based on 1 mole of the silica precursor. This is because when the content of the base catalyst is less than 0.01 mol, the condensation reaction rate is lowered and gel formation is delayed, and when it is greater than 5 mol, a non-uniform gel is formed.

In addition, at this time, the silica precursor is Methyltrimethoxysilane (MTMS), Methyltriethoxysilane (MTES), Tetramethyl orthosilicate (TMOS), Tetraethyl orthosilicate (TEOS), Phenyltrimethoxysilane (PTMS), Phenyltriethoxysilane (PTES), Dimethyldimethoxysilane (DMDMS), and Dimethyldiethoxysilane (DMDES). It may be any one or more selected from the group consisting of, but is not limited thereto.

In the present invention, the composite fibers 50 are laminated on top of the silica airgel/polyurethane composite layer and include polyamide and glass fibers, and the composite fibers include 50% by weight of polyamide and glass fibers ( Glass fiber, glass wool) 50% by weight and 1: 1 is mixed in a weight% ratio, and has an area density of 200 to 2000 g / m ² . The composite fiber serves to enhance the heat resistance of the composite, and when the areal density is less than 200 g/m ² , the sound-absorbing performance is reduced below a predetermined range so that noise cannot be removed, and when it exceeds 2000 g/m ² , the material As weight increases, fuel efficiency increases.

In the present invention, the aluminum sheet layer 70 is applied as a skin layer of a sound-absorbing insulating material, blocks the movement of radiant heat and provides flexibility so that it can be adhered to a region having a complex surface shape. To achieve this effect, the aluminum sheet layer has a thickness of 50 to 250 μm. Specifically, when the thickness of the aluminum sheet layer is less than 50 μm, the radiant heat blocking effect is insufficient, and when the thickness exceeds 250 μm, it is difficult to form and adhere to the composite, so the aluminum sheet layer is made of a thickness of 50 to 250 μm. and can be needle punched.

In the present invention, the sound-absorbing insulating material may further include binder layers 20, 40, and 60 between the respective layers.

The binder layer is included between each layer and adheres one layer to another layer. In general, a binder usable as a sound-absorbing insulating material for automobile interior may be used, and the type is not limited, but preferably an inorganic binder, More preferably, it is an inorganic binder using liquid sodium silicate, and the binder layer is formed with a thickness of 0.1 to 2 mm between each layer to provide adhesive strength and prevent material weight increase due to unnecessary thickness formation.

The sound-absorbing insulator for encapsulation of an automobile engine of the present invention can be closely applied to an encapsulation engine to more efficiently reduce thermal energy and noise emitted to the outside of the engine, thereby exhibiting improved insulation and sound-absorbing effects. It can be manufactured by hot forming, cold forming, and trimming in a multi-layer structure using members constituting the layers of.

Hereinafter, the present invention will be described in more detail as examples, but the present invention is not limited by the examples.

Example

1. Manufacture of sound-absorbing insulation

Example 1

(1) Preparation of silica airgel/polyurethane composite ( Hybrid PU-Silica Airgel Composite)

A mixture was prepared by mixing 10 moles of methanol, 10 moles of water, 0.003 moles of sulfuric acid, and 0.05 moles of aqueous ammonia based on 1 mole of the silica precursor Tetraethoxysilane (TMOS). Next, the mixture was stirred at room temperature for 20 hours, and then the mixture was infiltrated into the pores of the foamed polyurethane to form a gel through a condensation reaction. At this time, based on 100 parts by weight of the foamed polyurethane, the mixture was added at 100 parts by weight.

Thereafter, the mixture was aged in an oven at 50° C. for 1 day at atmospheric pressure, and the solvent was dried to prepare a silica airgel/polyurethane composite having a porosity of 80% or more through a sol-gel reaction.

FIG. 3 is a photograph (a) of polyurethane foam formed into a composite by combining silica airgel and an enlarged photograph thereof, indicating that a silica airgel/polyurethane composite has been manufactured.

(2) Manufacture of sound-absorbing insulation materials

As shown in FIG. 1, a sound absorbing heat insulating material was manufactured. First, after preparing the polymer resin layer 10, the binder layer 20 is formed on the upper surface of the polymer resin layer 10, and the prepared silica airgel-polyurethane composite layer ( 30), forming a binder layer 40 on the upper surface of the silica airgel-polyurethane composite layer 30, forming a composite fiber layer 50 on the upper surface of the binder layer 40, and forming the composite fiber layer (50) A binder layer 60 was formed on the upper surface, and an aluminum sheet layer 70 was formed on the upper surface of the binder layer 60 to manufacture a multi-layered sound-absorbing insulating material having a multi-layer structure.

Comparative Example 1

A multi-layered sound-absorbing insulator was manufactured in the same manner as in Example 1, except that the silica airgel-polyurethane composite layer 30 of Example 1 was formed as a polyurethane foam layer composed only of polyurethane foam.

2. Comparison of physical properties

In order to compare and confirm the thermal conductivity and sound absorption coefficient of the multilayer sound absorbing insulator according to the present invention, the thermal conductivity (thermal insulation performance) and sound absorption coefficient of the multilayer sound absorbing insulator prepared in Example 1 and Comparative Example 1 were measured by ASTM C518 hot plate method and MS 200- It was measured through the 39 analysis method and shown in Table 1 and Figures 4 and 5, and the sound absorption performance in Table 1 specified the average sound absorption coefficient values in the frequency band 1, 2, 3.15, and 5 kHz regions.

In addition, in order to confirm the effect of reducing fuel consumption due to the improvement of the insulation characteristics, after mounting the sound absorbing insulation of the present invention on an actual vehicle engine as shown in FIG. 6, CO ₂ emissions were measured using an FTP-75 (HWFET), 1.

division Thermal Conductivity (mW/mK) Average Coefficient of Absorption
(1, 2, 3, 15, 5 kHz) CO ₂ emissions
(g/km) Example 1 36.1 0.66 183.21 Comparative Example 1 40.1 0.53 187.96

Through Table 1 and FIGS. 4 to 6, the thermal conductivity of Example 1 was 36.1 mW/mK, which was reduced by 4.0 mW/mK compared to 40.1 mW/mK of Comparative Example 1. It can be seen that the heat insulating properties are improved by including the silica airgel/polyurethane composite layer in which the airgel is bonded to the silica.

In addition, it can be seen that the average sound absorption coefficient of Example 1 is improved by about 24.53% compared to 0.53 of Comparative Example 1 to 0.66.

In addition, it was confirmed that the CO ₂ emission of Example 1 was 183.21 g/km, which was reduced by about 2.5% compared to 187.96 g/km of Comparative Example 1.

Accordingly, by applying the sound absorbing and insulating material for engine encapsulation of the present invention to an engine, it is possible to provide more improved insulation characteristics for heat consumed by the engine and high sound absorbing performance for noise generated, and furthermore, reduced CO ₂ It can show the effect of improving fuel efficiency due to improved insulation characteristics through emissions.

10: polymer resin layer
20: binder layer
30: silica airgel/polyurethane composite layer
40: binder layer
50: composite fiber layer
60: binder layer
70: aluminum sheet layer

Claims (4)

A polymer resin layer made of a polymer resin;
a silica airgel/polyurethane composite layer laminated on top of the polymer resin layer;
a composite fiber layer laminated on top of the silica airgel/polyurethane composite layer and containing polyamide and glass fibers; and
Made of multiple layers, including; an aluminum sheet layer laminated on top of the composite fiber layer,
The polymer resin layer is a polyester nonwoven fabric,
The silica airgel/polyurethane composite is a structure in which the polyurethane after foaming is used as a support and the silica airgel is bonded in the polyurethane pores in a monolith form through a wet process Sound absorbing insulation for automotive engine encapsulation.
According to claim 1,
Sound-absorbing insulator for automotive engine encapsulation, characterized in that it further comprises an inorganic binder layer using liquid sodium silicate for imparting adhesive strength between the respective layers. delete delete