JPS6345980B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a sound absorbing material in the engine room of an automobile, and more specifically, it is attached to a wheel house and a dash panel in the engine room, and has excellent water resistance, oil resistance, and durability. The present invention also relates to a sound absorbing material that significantly reduces noise outside the vehicle. [Prior Art] Various soundproofing materials have been proposed for automobiles, but when the source of automobile noise, especially the engine room, is the engine room, the best soundproofing measures are water and oil. There is no sound-absorbing material that is strong and has a sufficient sound-absorbing effect, and methods to prevent engine noise from propagating into the passenger compartment include installing sound-insulating material on the inside of the darts panel that separates the engine compartment from the passenger compartment; Currently, in order to prevent the propagation of vibrations through the floor panel, methods such as heat-sealing damping material to the floor panel are used. [Problems to be Solved by the Invention] However, such measures alone are still insufficient as measures against vehicle interior noise. Currently, there is a demand for sound absorbing materials for engine compartments that have a reduced width. [Means for Solving the Problems] Therefore, the inventors of the present invention have conducted extensive research to develop a sound absorbing material that has sufficient sound absorbing properties, as well as extremely excellent water resistance, oil resistance, and durability. Laminated with synthetic resin fiber fleece and bulky non-woven fabric,
By forming it into a specific air flow resistance and shape after molding, we have developed a suitable material that has excellent sound absorption properties, as well as water resistance, oil resistance, and durability, leading to the present invention. The gist of the present invention is to provide a sound-absorbing material to be attached to a wheel house and a darts panel in an engine room, in which 5 to 200 parts by weight of bulky nonwoven fabric 2 and synthetic fiber material 100 parts by weight are used.
Contains parts by weight of synthetic resin components and has a bulk density of 4×
By heat-molding a laminate made of synthetic fiber fleece 3 of 10 ^-4 to 8 x 10 ^-2 g/cm ³ and providing a plurality of arbitrarily shaped overhangs, an independent air layer is formed, and the top of the overhang The height 4 is 5 to 400 m/m excluding the thickness 4' of the molded body, and the air flow resistance of at least the overhang is 30 to 300 dyne.
sec/cm ³ is a sound absorbing material for the interior of an automobile engine room, which is a molded body. In the present invention, the molded body to be attached to the countermeasure location is
It is obtained by heating and molding a laminate of a synthetic fiber fleece 3 on a bulky nonwoven fabric 2. The bulky nonwoven fabric 2 used in the present invention is made of animal fibers such as wool, vegetable fibers such as hemp and cotton, mineral fibers such as glass wool and rock wool, and acrylic, nylon, Tetron, and rayon. One or more types of synthetic resin fiber materials are defibrated and mixed, and a binder containing a thermosetting synthetic resin as a main component is spread to bind the fiber materials to form a bulky material. It is necessary that such thermosetting synthetic resin be in an uncured state before thermoforming. It is also economically preferable to use industrial waste such as fallen cotton, waste wool, and synthetic fiber waste as the fiber material. Bulky nonwoven fabrics generally have a thickness of 8 to 50 m/m.
It is preferable that the areal density is in the range of 400 to 4000 g/m ² . The synthetic fiber fleece 3 used by laminating on at least one side of the bulky nonwoven fabric in order to impart water resistance, oil resistance, and durability to the sound absorbing material is made of one or more of polyester fibers, polyamide fibers, and acrylic fibers having a high softening point. It is made of synthetic fibers of at least 100% of synthetic fibers, and its bulk density must be 4×10 ⁻⁴ to 8×10 ⁻² g/cm ³ . Bulk density is 4×10 ^-4 g/cm ³
If it is less than 8×10 ^-2 , it will be stretched during molding and cause scratches, and a sufficient protective layer will not be provided to the molded product.
If it exceeds g/cm ³ , it is not preferable because the moldability at acute angle portions is poor. The amount of resin contained in the synthetic resin is 5 to 100 parts by weight of synthetic fiber.
It is essential to mix 200 parts by weight. If it is less than 5 parts by weight, it has the disadvantage of poor rigidity and durability.
If it exceeds 200 parts by weight, the resin plate becomes substantially non-permeable, which is not preferable. Synthetic fiber fleece is laminated on at least one side of a bulky non-woven fabric and molded under heat and pressure at a temperature of 150~150℃.
A temperature of about 230°C is sufficient, and a molding time of about 1 to 6 minutes is sufficient. A pressure of 10 kg/cm ² or less is sufficient for heating and pressing. Since at least one side of the bulky nonwoven fabric is protected with a synthetic fiber fleece having a low bulk density, the sound absorbing material has excellent water resistance, oil resistance, and durability. In order to provide even better sound absorption, it is essential to maintain the air flow resistance of the sound absorbing material overhang between 30 and 300 dyne·sec/cm ³ . If it is less than 30dyne・sec/ ^cm3 , not only can no sound absorption effect be expected, but it is also impractical in terms of strength and shape retention.
If it exceeds ^cm3 , it becomes a hard plate and is useless as a sound absorbing material. The overhang provided on the sound absorbing material may have any shape, and the height to the top of the overhang must be 5 to 400 m/m excluding the thickness of the molded body, preferably 5 to 100 mm. The size of the overhang contributes to the shift of the frequency at which the sound absorption coefficient is the best, so the overhang needs to have an effective shape. If the height of the overhang is less than 5m/m, the frequency range with the best sound absorption will be in the high frequency range, which is not practical as a noise countermeasure for the engine room, and if the height of the overhang exceeds 400m/m, installation work will be required. Not only is the sound absorption coefficient inferior, but the frequency range where the sound absorption coefficient is the best is a low frequency range, which has the disadvantage that it is not practical as a noise countermeasure for the engine room. In addition to the case where the present invention is directly attached to a panel of an automobile, it can also be used in conjunction with soundproofing material that is attached for noise treatment. [Example] Example 1 30 parts by weight of recycled wool and 50 parts by weight of fallen cotton were opened and mixed, and phenolic resin powder 20 was prepared with a melting point of 140°C and a reaction temperature of 170°C.
After scattering and mixing the weight parts and making fleece with a fleece forming machine, it is passed through a heating furnace at 150℃ to a thickness of 24m/m.
A bulky nonwoven fabric with an areal density of 1000 g/m ² was obtained. Bulk density containing 5 parts by weight of acrylic resin as an adhesive binder in solid content per 100 parts by weight of fiber.
10 ^-2 g/cm ³ (thickness 10m/m, areal density 100g/m ² )
Polyester fiber fleece (commonly known as resin cotton) is sprayed with an emulsion of vinyl acetate-acrylic copolymer to give a solid content of 80 parts per 100 parts by weight of the fleece.
The semi-finished product, which was sprayed in an amount equal to parts by weight and preheated at 80° C. for 5 minutes to volatilize the water and make it easier to handle, was laminated on both sides of the bulky nonwoven fabric. Next, from a new mold of non-ventilated sound insulating material with four corners attached to the car body to cover the lower part of the engine, we made a mold that corresponds to the almost flat part and the height excluding the thickness of the molded material. Twelve overhanging parts are provided on a truncated pyramid with a diameter of 30 m/m, the top of the overhang is 5 m/m thick, and a flat part is 2 m/m thick corresponding to the periphery of the molded body. ,
A bulky nonwoven fabric with fleece laminated on both sides was pressure-molded for 2 minutes under heating conditions of 180°C. The air flow resistance at the top of the overhang is 104dyne・sec/
It was warm at ^cm3 . Example 2 Bulk density 7×10 ^-2 g/cm ³ (thickness 10 m/m, areal density 700 g/cm 3 ) containing 5 parts by weight solids of acrylic resin as an adhesive binder per 100 parts by weight of fibers.
m ² ) polyester fiber fleece (commonly known as resin cotton) was sprayed with an emulsion of vinyl acetate-acrylic copolymer so that the solid content was 80 parts by weight per 100 parts by weight of the fleece, and then heated to 80°C.
The semi-finished product, which was preheated for 5 minutes to volatilize the water and make it easier to handle, was laminated on both sides of the same bulky nonwoven fabric as in Example 1. Next, from a new mold of non-ventilated sound insulating material with four corners attached to the car body to cover the lower part of the engine, we made a mold that corresponds to the almost flat part and the height excluding the thickness of the molded material. Twelve overhangs are provided on a truncated pyramid with a diameter of 100 m/m, the top of the overhang is 5 m/m thick, and a flat portion is 2 m/m thick to correspond to the periphery of the molded body. A bulky nonwoven fabric with fleece laminated on both sides was pressure-molded under heating conditions of 180° C. for 2 minutes. The air flow resistance at the top of the overhang is 280dyne・
It was sec/ ^cm3 . Example 3 Bulk density 5×10 ^-3 g/cm ³ (thickness 10 m/m, areal density 50 g/cm 3 ) containing 50 parts by weight solids of acrylic resin as an adhesive binder per 100 parts by weight of fibers.
m ² ) polyester fiber fleece (commonly known as resin cotton) was sprayed with an emulsion of vinyl acetate-acrylic copolymer so that the solid content was 80 parts by weight per 100 parts by weight of the fleece, and then heated to 80°C.
The semi-finished product, which was preheated for 5 minutes to volatilize the water and make it easier to handle, was laminated on both sides of the same bulky nonwoven fabric as in Example 1. Next, from a new mold of non-ventilated sound insulating material with four corners attached to the car body to cover the lower part of the engine, we made a mold that corresponds to the almost flat part and the height excluding the thickness of the molded material. Twelve overhangs are provided on a truncated pyramid with a diameter of 200 m/m, the top of the overhang has a thickness of 5 m/m, and a flat part is provided with a thickness of 2 m/m corresponding to the periphery of the molded body. A bulky nonwoven fabric with fleece laminated on both sides was pressure-molded under heating conditions of 180° C. for 2 minutes. The air flow resistance at the top of the overhang is 35dyne・
It was sec/ ^cm3 . Example 4 Bulk density 2×10 ^-2 g/cm 3 (thickness 10 m/m, areal density 200 g/cm ^{3 )} containing 5 parts by weight of acrylic resin as an adhesive binder in solid content per 100 parts by weight of fiber.
m ² ) polyester fiber fleece (commonly known as resin cotton) was sprayed with an emulsion of vinyl acetate-acrylic copolymer so that the solid content was 80 parts by weight per 100 parts by weight of the fleece, and then heated to 80°C.
The semi-finished product, which was preheated for 5 minutes to volatilize the water and make it easier to handle, was laminated on both sides of the same bulky nonwoven fabric as in Example 1. Next, from a new mold of non-ventilated sound insulating material with four corners attached to the car body to cover the lower part of the engine, we made a mold that corresponds to the almost flat part and the height excluding the thickness of the molded material. Twelve overhangs are provided on a truncated pyramid with a diameter of 10 m/m, the top of the overhang is 5 m/m thick, and a flat portion is 2 m/m thick to correspond to the periphery of the molded body. ,
A bulky nonwoven fabric with fleece laminated on both sides was pressure-molded for 2 minutes under heating conditions of 180°C. The air flow resistance at the top of the overhang is 140dyne・sec/
It was warm at ^cm3 . [Test method] The molded bodies of Examples 1 to 4 were attached with screws to the four sides of a nearly trapezoidal non-breathable sound insulating material whose four corners were attached to the car body in a manner that covered the lower part of the engine. . The sound absorption coefficient of this material was measured in a small reverberation chamber owned by our company. [Test Results] The table below shows the sound absorption coefficient at each frequency before immersion in water and after immersion in water and drying.

〔Test method〕

Moreover, the sound absorption coefficient and the tensile strength and tear strength according to JIS K 6301 were also measured for the molded product which was immersed in water for 24 hours and then dried. 〔Test results〕

〔effect〕

As mentioned above, it was also revealed that it is a sound absorbing material with excellent sound absorption coefficient and excellent water resistance, with almost no difference in sound absorption coefficient and strength compared to before immersion in water.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a molded body mounted on a sheet metal member or a base. 1... Sheet metal member, 1'... Substrate, 2... Bulky nonwoven fabric,
3...Synthetic fiber fleece, 4...Height from the flat part to the top of the overhanging part, 4'...Thickness of the molded body.

Claims (1)

[Claims] 1 A sound-absorbing material to be attached to the wheel house and darts panel in the engine room, containing 5 to 5 parts by weight of bulky nonwoven fabric 2 and 100 parts by weight of synthetic fiber material.
Contains 200 parts by weight of synthetic resin component and has a bulk density of 4
×10 ^-4 ~ 8 × 10 ^-2 g/cm ³ A laminate made of synthetic fiber fleece 3 is heat-molded and provided with several overhangs of arbitrary shapes to form an independent air layer, and the overhangs The height 4 to the top of the molded body, excluding the thickness 4', is 5 to 400 m/m, and the air flow resistance of at least the overhanging part is 30 to 300 dyne.
A sound-absorbing material for use in an automobile engine room, characterized by being a molded body with sec/ ^cm3 .