JPH072329Y2 - Soundproof structure for automobile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a soundproofing structure for an automobile, and more specifically, to prevent noise in a dash panel, a floor panel, a tire house, a rear luggage compartment, etc. of an automobile. The present invention relates to a soundproof structure for an automobile, which is generally used for the interior, shuts off the sound transmitted from the outside of the vehicle compartment or the sound generated from the vehicle body panel, and is lightweight and has a high surface flatness.

[Prior Art] As a conventional soundproof structure for an automobile, there is, for example, one as shown in FIG. This shows the cross-sectional shape of the floor insulator used for sound insulation of the floor part, and 10 is the body panel, which is a damping material usually made of asphalt sheet.
20 is welded. 30 is a sound absorbing layer made of felt or the like, 40 is a surface sound insulating layer made of carpet, and the back surface of the surface sound insulating layer 40 is usually lined with a thermoplastic resin for moldability of the carpet and for adding mass. . The sound absorbing material layer 30 such as the felt and the carpet layer 40 are generally bonded by an adhesive means or the like.

As another example, FIG. 6 shows a cross-sectional shape of the dash insulator. In the case of a dash insulator, a felt is often used as the sound absorbing material layer 30, and a PVC sheet or the like is often used as the surface sound insulating layer 40.In this case also, the sound absorbing material layer 30 and the surface sound insulating layer 40 are generally bonded by an adhesive means or the like. ing.

For both floor and dash insulators, damping material such as asphalt sheet 20
Is used for damping the body panel, and the surface sound insulation layer 40, such as a carpet or PVC sheet, which is integrated with the sound absorbing material layer 30, is used as a sound insulation structure.

[Problems to be solved by the invention] However, in such a conventional soundproof structure for an automobile, an asphalt damping material used for damping a vehicle body panel, a felt and a carpet or a PVC sheet are used. The integrated insulator has the functions of vibration damping and sound insulation separately, and is attached in a separate process even in the automobile assembly line, and there is a problem that it takes man-hours.

Although the afphalt damping material is an inexpensive damping material, it has a problem that it is heavy and cannot be sufficiently welded to a vertical wall such as a dash panel.

Further, with a sound absorbing material such as felt, it is not possible to have a molding die that is in close contact with the vehicle body panel and can sufficiently absorb the irregularities of the vehicle body panel, and as a result, the sound insulation performance is deteriorated.
Further, there is a problem that surface smoothness is not obtained, and particularly in the case of a floor insulator, quality such as appearance quality and flatness feeling is deteriorated.

In particular, for a body panel portion where it is difficult to weld or attach a damping material, there is a problem that it is difficult to take sufficient soundproofing measures only with a sound absorbing material such as felt or a surface sound insulation layer.

[Object of the Invention] Therefore, an object of the present invention is to provide a soundproof structure for a vehicle which is lightweight, has high flatness, and has a large soundproof effect.

Another object of the present invention is to provide a soundproofing structure for an automobile, capable of removing heavy aphalt-type damping material or reducing the thickness thereof and reducing the weight of the vehicle body.

[Means for Solving Problems] A soundproof structure for a vehicle according to the present invention is a soundproofing / vibrating material to be attached to a vehicle body panel of a vehicle as a first layer: an asphalt sheet laid along the shape of the vehicle body panel. 2nd layer: Asphalt-urethane integrated foam made of a prepolymer consisting of asphalt and polyol / isocyanate molded in the shape of the ribs of the vehicle body panel, 3rd layer: felt or urethane foam The sound absorbing material layer formed by solidifying the strips of, the fourth layer: the surface sound insulating layer, and a structure in which the layers are sequentially laminated.

A preferred embodiment of the present invention is that the asphalt-urethane integrated foam foam layer is obtained by heating a slab product of the asphalt-urethane integrated foam foam, patterning with a press, and molding. More preferably, it is obtained by heating a slab product (flat product) of asphalt-urethane integrated foamed foam in advance and cold pressing it with a mold processed into a vehicle body panel shape. In this means, generally, it is possible to heat to about 200 ° C. and press it for about 1 minute to mold it into a predetermined shape. Further, heating and molding can be performed simultaneously with a hot press.

Another embodiment of the present invention is that the asphalt-urethane integrated foam foam layer is obtained by injecting and foaming the asphalt-urethane integrated foam foam into a mold.

[Operation] In the structure of the conventional soundproofing material for automobiles, a damping material such as an afphalt sheet welded to the vehicle body panel and a flat sound absorbing material layer,
Since the surface sound insulation layer was used, the unevenness of the rib structure formed on the vehicle body panel could not be absorbed, and there were problems such as deterioration of soundproof performance and deterioration of floor flatness. By molding the asphalt-urethane integrated foamed foam into a vehicle body panel shape and closely contacting it with the vehicle body panel, and by laminating a sound absorbing material layer and a surface sound insulation layer on the molded asphalt-urethane integral foam layer,
It is possible to form a soundproof structure for a vehicle which is lightweight, has high flatness, and has a large soundproof effect.

Further, since the asphalt-urethane integrated foam is used in contact with the vehicle body panel, it is possible to reduce the weight of the vehicle body by removing heavy asphalt-based damping material or reducing the thickness.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a sectional view of an essential part showing a reference example of the present invention.

In the figure, reference numeral 1 denotes an automobile body panel, which has a rib shape of unevenness 1A. Reference numeral 5 is an asphalt-urethane integrated foamed foam molded along the rib-shaped irregularities 1A of the vehicle body panel 1 and is provided in contact with the vehicle body panel 1.

3 is a sound-absorbing material layer which is on the vehicle interior side of the asphalt-urethane integrated foam foam layer 5 and is bonded to the asphalt-urethane integrated foam foam layer 5, and is usually made by hardening felt or urethane foam strips. ing.

4 is a surface sound insulation layer. In the case of floor insulators, a carpet lined with a thermoplastic resin layer is used, and in the case of dash insulators, PVC is used as the surface sound insulation layer.
Sheets are often used.

The sound absorbing material layer 3 and the asphalt-urethane integrated foam foam layer 5 according to the present invention may be adhered to the sound absorbing material layer 3 at the time of heating, pressure bonding and molding the asphalt-urethane integrated foam foam, or may be bonded after molding. May be. When the asphalt-urethane integrated foam is further injected and foamed by a mold, the sound absorbing material layer 3 can be placed in the mold and bonded simultaneously with the injection and foaming.

Next, an embodiment of the present invention will be described with reference to FIG. The figure is a cross-sectional view of essential parts showing an embodiment of the present invention.

In this embodiment, a vehicle body panel 1 is welded with a damping material 2 such as an asphalt sheet. Asphalt
The urethane integrated foam layer 5 is formed so as to fill the inner surface of the panel along the rib-shaped irregularities of the vehicle body panel 1A. 3 is a sound absorbing layer, and 4 is a surface sound insulating layer.

In the case of the present embodiment, the vibration damping material 2 and the asphalt-urethane integrated foam foam layer 5 can impart a high degree of vibration damping performance to the vehicle body panel 1. And in this structure,
It is possible to remove or reduce the thickness of the damping material, such as asphalt sheet, which has been conventionally welded thickly, and contribute to the reduction of the weight as a whole.

The asphalt-urethane integrated foam used in the above examples is a vibration-damping and sound-absorbing foam that utilizes the vibration-damping property of asphalt. Other vibration-damping and sound-absorbing foams using asphalt include asphalt-impregnated foams, but when heat-molding, asphalt-urethane integrated foams are better molded.

Hereinafter, a method of manufacturing foamed type and impregnated type foams, and sound absorbing performance in the low and middle frequency range will be described.

The foaming type is an integrated foam made of asphalt / water emulsion and a water-soluble prepolymer (JP-A-61-237630).
No. Reference: Comparative example of the present invention), or an integral foam made of a prepolymer of asphalt and polyol / isocyanate (the present invention). The former has a ventilation performance of about 70cc / cm ² related to low frequency sound absorption. / sec, which is low and therefore the low frequency sound absorption performance is poor (curve A in Fig. 3
reference). The latter has a ventilation performance of 10 cc / cm ² / sec or less, and has low air permeability. Therefore, the sound absorption performance at low frequencies is much better than the former (see the curve B in FIG. 3).

On the other hand, the impregnated type is made by impregnating urethane foam with asphalt by post-treatment (see No. Sho 61-16950, a comparative example to the present invention). Highly breathable, showing a value of about 100 cc / cm ² / sec or more. Therefore, the low-frequency sound absorbing performance is lower than that of the foamed polyurethane foam with low air permeability (see the curve C in FIG. 3).

Here, the air permeability is measured by a JIS L-1004 Frazier type tester. The value of breathability differs for the same material if the thickness is different. In the present invention, the values measured using all materials with a thickness of 10 mm were used. For example, the air permeability of general polyurethane foam is 40 to 120 cc / cm ² / sec. The breathability and sound absorption of the asphalt-containing polyurethane foam are correlated, and the lower the breathability, the better the sound absorption performance at low frequencies.

The use of asphalt-containing polyurethane foam, whether it is a foam type or an impregnated type, improves sound insulation performance compared to the conventional structure, but the impregnated type has high air permeability and poor low frequency sound absorption performance, whereas the foam type does It has relatively low properties and has good low-frequency sound absorption performance. In particular, the low-frequency sound absorption performance of the asphalt-urethane integrated foam made of the prepolymer of asphalt and polyol / polyisocyanate according to the present invention is extremely good. .

On the other hand, the damping performance is almost the same for both the foaming type and the impregnating type because asphalt is used. However, in the foam type, since the structure of the bubbles can be controlled, the air permeability can be further lowered, and the sound insulation performance can be greatly improved.

The following asphalt-urethane integrated foam used in the present invention is also preferably used. That is,
A polyalkylene polyol having at least two or more hydroxyl groups in the molecule and emulsifying and dispersing asphalt in advance, and a polyisocyanate having two or more isocyanate groups are injected into a mold together with a catalyst and a foaming agent and reacted. It was obtained by

As a polyol used for producing an emulsion of asphalt and a polyol, a polyalkylene polyol used for producing a general polyether polyurethane foam is preferably used in terms of moldability and cost. As these polyalkylene polyols,
For example, a polyhydric alcohol or an amine compound obtained by addition-polymerizing alkylene oxide is used.

Examples of the polyhydric alcohol include ethylene glycol,
Examples thereof include dihydric alcohols such as propylene glycol and 1,4-butanediol diethylene glycol, trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric or higher alcohols such as pentaerythritol, sorbitol and sucrose. Examples of the amine compound include aliphatic polyamines such as ethylenediamine and hexamethylenediamine, aromatic polyamines such as phenylenediamine and tolylenediamine, and alkanolamines such as monoethanolamine, diethanolamine and triethanolamine.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and among these, ethylene oxide and propylene oxide are preferably used.

As the polyol, a trifunctional polyether polyol having a molecular weight of 3000 to 5000 and having a primary OH at the terminal is used, in which both ethylene oxide and propylene oxide are used from the viewpoint of moldability and curing property.

As an asphalt component dispersed in fine particles in these polyols, straight asphalt, blown asphalt, semi-blown asphalt, cutback asphalt and the like are used.

The ratio of polyalkylene polyol and asphalt is 10
0:10 to 200 (weight ratio) is preferable, 100: 50 to 150 is more preferable from the sound and vibration characteristics of the obtained molded foam, and the higher the asphalt content to be emulsified and dispersed, the more the foam damping characteristics improve.

The emulsification method of the polyalkylene polyol and asphalt is not limited, but an emulsification dispersion method using a surfactant is preferable. For example, a method in which a surfactant in the range of HLB 13 to 18 is added to polyalkylene polyol heated to about 100 ° C., and then asphalt heated and melted at 100 to 200 ° C. is emulsified and dispersed using a stirrer such as a homogenizer is preferable.

The particle diameter of the asphalt fine particles emulsified and dispersed in the polyalkylene polyol is preferably 2 to 50 μm, more preferably 5 to 20 μm. This is because it is possible to prevent contamination of the mold surface and the like due to asphalt bleeding.

In order to foam-mold the asphalt-dispersed polyalkylene polyol obtained by the above method in a mold, the asphalt-dispersed polyol and polyisocyanate having two or more isocyanate groups are mixed and stirred with a catalyst, a foaming agent, etc. and injected into the mold. do it.

As the polyisocyanate used here, tolylene diisocyanate, aromatic polyisocyanate such as diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, alicyclic polyisocyanate such as isophorone diisocyanate, aliphatic polyisocyanate such as hexamethylene diisocyanate, or these polyisocyanates A modified isocyanate and a combination of two or more of these are also possible.

Other components that can be added during foam molding control various components used in the production of general polyurethane foam, such as amine-based catalysts and tin-based catalysts, water and freon as foaming agents, and foam cells. For example, a silicon-based surface active agent may be used. Furthermore, if necessary, an inorganic filler, a flame retardant or the like can be added. In the present invention, a third layer other than the layer of the present invention may be provided if necessary.

[Examples] Next, the results of a comparative experiment on the soundproofing effect of the conventional soundproofing structure and the soundproofing structure of the present example are shown.

As a conventional example, a laminate assuming a floor insulator having the structure shown in FIG. 5 was used. A 0.8t iron plate was used as the body panel 10 and a 4mm thick asphalt damping material 20 was welded to this. As the adsorbent layer 30, a resin felt having a thickness of 15 mm was used. As the surface sound insulation layer 40, a carpet lined with a polyethylene resin layer was used.

On the other hand, the laminated body shown in FIG. 2 was used as the soundproof structure according to this example. The body panel 1 is the same as the conventional example
0.8t iron plate, 2 is a 2mm thick asphalt damping material welded to this. Numeral 5 is an asphalt-urethane integrated foamed foam layer molded in a rib shape of the iron plate 1 so as to follow the irregularities 1A, and a 10 mm slab product is heated at 200 ° C. and then molded into a predetermined shape by pressing. 3 is a resin felt as a sound absorbing layer, and 4 is a carpet lined with polyethylene resin as in the conventional structure.

In evaluating the soundproofing effect, vibration was applied to each base iron plate (10 in FIG. 5 and 1 in FIG. 2) and the sound pressure level of the solid sound generated from each sample was measured. The results are shown in FIG. Considering that the lower the generated sound pressure level is, the better the effect is, the embodiment of the present invention is superior to the comparative example having the conventional structure in the soundproofing effect.

On the other hand, the weight per unit area of the soundproofing material excluding the iron plate is 7.6 kg / m ^{2 in} the comparative example and 5.6 kg / m ^{2 in} the example, and this example reduces the weight by about 2 kg / m ^2. Has become.

[Effects of the Invention] As described above, according to the present invention, an asphalt-urethane integrated foam layer obtained by integrally foaming asphalt and urethane along the rib shape of the vehicle body panel is applied to the vehicle body panel. Since it has a structure in which a sound-absorbing material layer and a surface sound-insulating layer are sequentially laminated on the integrated foam layer, the structure is lightweight, has high flatness, and has a large sound-proofing effect for automobiles. be able to. Further, according to the present invention, the asphalt-urethane integrated foam disposed in the second layer is formed of a prepolymer composed of asphalt and polyol / polyisocyanate molded in a shape along the rib shape of the vehicle body panel. Therefore, as shown by the curve B in FIG. 3, as compared with the asphalt-urethane foam of the type in which urethane foam is impregnated with asphalt, and the integral foam composed of the asphalt / water emulsion and the water-soluble prepolymer. In particular, the sound insulation performance in the low frequency region is particularly good, and therefore, the amount of the damping material formed of the asphalt sheet used as the first layer can be remarkably reduced, which contributes to the reduction of the vehicle body weight. It is large and can solve the above-mentioned problems.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part showing a reference example of the present invention, FIG. 2 is a cross-sectional view of a main part showing an embodiment of the present invention, and FIG. 3 is a graph showing a relationship between frequency and normal incident sound absorption coefficient. Curve B is the present invention,
Curves A and C are comparative examples, FIG. 4 is a graph showing the measurement result of the sound pressure level, and FIGS. 5 and 6 are cross-sectional views of a main part showing a conventional example. 1: Body panel 2: Damping material 3: Sound absorbing material layer 4: Surface sound insulation layer 5: Asphalt-urethane integrated foam layer

Claims (1)

[Scope of utility model registration request] 1. A soundproofing / vibrating material to be attached to a vehicle body panel of an automobile, the first layer: a damping material formed of an asphalt sheet laid along the shape of the vehicle body panel, and the second layer: ribs of the vehicle body panel. Asphalt-urethane integrated foam made of prepolymer consisting of asphalt and polyol / isocyanate molded in conformity with the shape, 3rd layer: sound absorbing material layer formed by solidifying felt or urethane foam strips, 1st layer A soundproof structure for automobiles having a structure in which each of four layers: a surface sound insulation layer, is sequentially laminated.