JPH0542935Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to soundproof interior materials for automobiles, and more specifically, for the purpose of preventing noise in automobile dart panels, floor panels, tire houses, rear luggage compartments, etc. This invention relates to a soundproof interior material for automobiles, which is generally used for interior decoration, blocks sound transmitted from outside the vehicle interior, or sound generated from vehicle body panels, and has an improved flat surface.

[Prior Art] As a conventional soundproof interior material for automobiles, there is one shown in FIG. 5, for example. Conventional soundproof interior materials have a simple structure consisting of a sound absorbing material layer and a sound insulating layer. Specifically, as shown in the figure, a damping material 20 usually made of an asphalt sheet is tightly attached to a vehicle body panel 10. has been done. 30 is a sound absorbing material layer made of a flat plate of felt or the like. Reference numeral 40 denotes a surface sound insulation layer, and in the case of a floor insulator, a carpet backed with a thermoplastic resin layer is used to add mass to improve sound insulation performance and to improve moldability. In this case, the above-mentioned sound absorbing material layer 30 and surface sound insulating layer 40 are generally bonded together by adhesive means or the like.

Further, as another example, the cross-sectional shape of a dart insulator is shown in FIG. A damping material 20 made of asphalt sheet or the like is welded to the vehicle body panel 10. Felt is often used as the sound absorbing material layer 30 and PVC sheet etc. are often used as the surface sound insulating layer 40. In this case as well, generally the sound absorbing material layer 30
and the surface sound insulating layer 40 are bonded together by adhesive means or the like.

In both the floor insulator and the dart insulator, the damping material 20 such as an asphalt sheet is used for damping the vehicle body panel, and is made of a carpet or PVC sheet integrated with the sound absorbing material layer 30. The surface sound insulation layer 40 is used as a sound insulation structure.

[Problems to be Solved by the Invention] However, in the case of such conventional soundproof interior materials for automobiles, countermeasures are required for the "muffled sound" in the vehicle interior. In the structures shown in FIGS. 5 and 6, the following method is known as a method for improving low-frequency sound insulation performance around 500 Hz or less and reducing noise inside the vehicle interior.

(a) Increase the thickness of asphalt-based damping material.

(b) Increase the thickness of the sound absorbing material layer.

(C) Increase the weight of the surface sound insulation material layer.

However, methods (a) and (c) increase the weight of the vehicle and worsen the fuel efficiency of the vehicle, and method (b) has the problem that the interior space of the vehicle becomes narrow.

Sound-absorbing materials such as felt cannot be molded to adhere tightly to car body panels and sufficiently absorb unevenness such as the rib shape of car body panels, and as a result, soundproofing performance deteriorates due to insufficient sealing properties. This will result in a decrease in soundproofing performance against high-frequency sounds (for example, below 500 Hz). Furthermore, the inability to absorb the unevenness of the rib shape of the car body panel has the disadvantage that the surface sound insulation layer does not have a smooth surface, and in the case of floor insulators in particular, it reduces the quality such as flat feeling. Ta.

[Purpose of the invention] Therefore, the purpose of the invention is to improve the soundproofing at low frequencies (for example, below 500Hz) without changing the thickness or weight of the soundproofing material.
It can improve the soundproofing performance against the sound of
Another object of the present invention is to provide a soundproof interior material for automobiles that can improve flat feeling and further improve soundproofing performance.

[Means for Solving the Problems] The soundproof interior material for a vehicle according to the present invention is a soundproof interior material for a vehicle that is attached to a body panel of a vehicle, and is made of urethane foam or urethane foam in a shape that follows the rib shape of the body panel. The first layer is a sound absorbing material layer made by hardening and molding small pieces, the second layer is an asphalt-urethane integral foam made of a prepolymer made of asphalt and polyol isocyanate, and the third layer is a surface sound insulation layer laminated in sequence. It is characterized by having.

In a preferred embodiment of the present invention, the sound absorbing material layer is obtained by heating a slab product (flat product) of urethane foam or strips of urethane foam, and then molding and molding with a press. More preferably, it is obtained by preheating urethane foam or hardened pieces of urethane foam (flat material) and cold-pressing it in a mold formed into the shape of a car body panel. In this method, generally 200℃
It can be heated to a certain degree and molded into a predetermined shape by applying pressure for about 1 minute. Further, heating and molding can be performed simultaneously using a hot press.

In another embodiment of the present invention, the sound-absorbing material layer is obtained by injecting a urethane raw material (Utaren foam raw material or urethane foam strips) into a mold, foaming it, and molding it. It is. In this case, the soundproof interior material for automobiles of the present invention can be obtained by setting a slab sheet of asphalt-urethane integral foam in a mold in advance.

[Function] By providing an asphalt-urethane integrally foamed foam made of a prepolymer made of asphalt and polyol/isocyanate between the sound absorbing material layer and the surface sound insulating layer, the thickness and weight of the sound insulating material are hardly changed, and the Soundproofing performance can be improved, and by molding the sound absorbing material layer into the rib shape of the car body panel,
It is possible to improve the flat feeling and further improve the soundproofing performance.

[Example] Hereinafter, an example of the present invention will be described based on the accompanying drawings. FIG. 1 is a sectional view of essential parts showing an embodiment of the present invention.

In the figure, reference numeral 1 denotes a body panel of an automobile, which has a rib shape with unevenness 1A. A vibration damping material 2 is attached to the vehicle body panel 1, and is mainly made of asphalt-based material.

Reference numeral 3 denotes a sound absorbing material layer molded to follow the rib-shaped unevenness 1A of the vehicle body panel 1, and is made of urethane foam or hardened pieces of urethane foam.

4 is an asphalt-urethane integral foam layer attached to the sound absorbing material layer 3;
Usually used in the mm range. Asphalt-urethane integrally foamed foam tends to have better performance as the specific gravity increases, but if the specific gravity increases too much, the weight of the vehicle increases and the benefits of its use are diminished. From this point of view as well, the specific gravity of the asphalt-urethane integrally foamed foam is preferably in the range of 0.03 to 0.2.

5 is a surface sound insulation layer, in the case of a floor insulator, a carpet lined with thermoplastic resin is used, and in the case of a dart insulator, a carpet lined with thermoplastic resin is used.
PVC sheets etc. are often used.

Next, another embodiment of the present invention will be explained based on FIG. This figure is a sectional view of a main part showing another embodiment of the present invention.

In this embodiment, a flat material 3A such as felt or urethane foam is laminated on a part of the sound absorbing material layer 3, which is formed by hardening and molding urethane foam or urethane foam strips, so as to follow the shape of the vehicle body panel 1. be.

When the sound absorbing material layer 3 is heat molded from urethane foam or a flat object made of hardened urethane foam strips, if the sound absorbing material layer 3 is thick, the heat molding takes a long time. In order to avoid this, a part of the sound absorbing material layer 3 can be replaced with a flat material such as felt or a slab product such as a urethane sheet to prevent the molding time from increasing.

The asphalt-urethane integrally foamed foam used in the above embodiments is a vibration-damping and sound-absorbing foam that utilizes the vibration-damping properties of asphalt. Asphalt-impregnated foams are other types of vibration damping and sound absorbing foams that use asphalt.

The manufacturing method of each of the foam type and impregnated type foams and their sound absorption performance in the medium and low frequency range will be explained below.

The foam type is an integral foam made of asphalt/water emulsion and water-soluble prepolymer (see JP-A No. 61-237630: comparative example for the present invention);
Alternatively, it is an integral foam (this invention) made of a prepolymer made of asphalt and polyol/ ^isocyanate . Therefore, low frequency sound absorption performance is poor (curve A in Figure 3).
reference). The latter has an air permeability of 10 c.c./cm ² /sec or less, and has low air permeability. Therefore, the low frequency sound absorption performance is much better than the former (see curve B in Fig. 3).

On the other hand, the impregnated type is one in which urethane foam is impregnated with asphalt by post-treatment (see Utility Model Application Publication No. 16950/1983: comparative example for the present invention).
The impregnated type asphalt-containing polyurethane foam has high air permeability because it is impregnated with asphalt, and exhibits a value of about 100 c.c./cm ² /sec or more. Therefore, the low-frequency sound absorption performance is worse than that of the asphalt-containing polyurethane foam, which is a foam type with low air permeability (see curve C in FIG. 3).

Here, the air permeability is measured using a JIS L-1004 Frazier type tester. Even if the material is the same, the breathability value will differ if the thickness is different. In this invention, we used values measured using all materials with a thickness of 10 mm. For example, the breathability of general polyurethane foam is 40~
It is 120 c.c./cm ² /sec. There is a correlation between the breathability and sound absorption coefficient of asphalt-containing polyurethane foam.
The lower the air permeability, the better the low frequency sound absorption performance.

Whether it is a foamed type or an impregnated type, the use of asphalt-containing polyurethane foam provides better sound insulation performance than conventional structures, but the impregnated type has high air permeability and poor low-frequency sound absorption performance, whereas the foamed type has poor ventilation performance. In particular, the asphalt-urethane integrated foam made of a prepolymer made of asphalt and polyol/polyisocyanate according to the present invention has extremely good low-frequency sound absorption performance. .

On the other hand, the vibration damping performance is almost the same for both the foamed type and the impregnated type as they use asphalt. However, in the case of the foam type, the structure of the bubbles can be controlled, so the air permeability can be further reduced, and the sound insulation performance can be further improved.

The asphalt-urethane integral foam used in the present invention may be as follows. That is, a polyalkylene polyol having at least two or more hydroxyl groups in the molecule and prepared by emulsifying and dispersing asphalt in advance, and a polyisocyanate having two or more isocyanate groups as a catalyst,
It is obtained by injecting it into a mold together with a foaming agent and allowing it to react.

As the polyol used to produce the asphalt-polyol emulsion, polyalkylene polyols, which are used in producing general polyether-based polyurethane foams, are preferably used from the viewpoint of moldability and cost. As these polyalkylene polyols, for example, those obtained by addition polymerizing alkylene oxide to a polyhydric alcohol or an amine compound are used.

Examples of polyhydric alcohols include dihydric alcohols such as ethylene glycol, propylene glycol, and 1,4-butanediol diethylene glycol, and trihydric alcohols such as glycerin and trimethylolpropane.
Examples include alcohols with a valence of 4 or more, such as pentaerythritol, sorbitol, and sucrose. Examples of amine compounds 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, etc. Among these, ethylene oxide and propylene oxide are preferably used.

For the polyol, both ethylene oxide and propylene oxide are used from the viewpoint of moldability and curing properties, and a polyol with a molecular weight of 3000 and a primary OH at the end is used.
-5000 trifunctional polyether polyols are preferred.

Further, as the asphalt component dispersed in fine particles in these polyols, straight asphalt, blown asphalt, semi-blown asphalt, cutback asphalt, etc. are used.

The ratio of polyalkylene polyol and asphalt is preferably 100:10 to 200 (weight ratio), and from the sound vibration characteristics of the resulting mold foam to 100:50 to 100:50.
150 is more preferable, and the more asphalt content that is emulsified and dispersed, the better the damping properties of the foam will be.

Although the method for emulsifying the polyalkylene polyol and asphalt is not limited, a method of emulsifying and dispersing using a surfactant is preferred. For example, a method of adding a surfactant having an HLB range of 13 to 18 to a polyalkylene polyol heated to about 100°C, and then emulsifying and dispersing the asphalt heated and melted at 100 to 200°C using a stirrer such as a homogenizer is preferred.

The particle size 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 other surfaces 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 a polyisocyanate having two or more isocyanate groups are mixed and stirred together with a catalyst, a blowing agent, etc., and then injected into the mold. do it.

Examples of the polyisocyanate used here include aromatic polyisocyanates such as tolylene diisocyanate and diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate,
Alicyclic polyisocyanates such as isophorone diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, modified products of these polyisocyanates, and combinations of two or more of these polyisocyanates are also possible.

Other components that can be added during foam molding include various components used in the production of general polyurethane foam, such as amine catalysts and tin catalysts, water and freon as blowing agents, and for controlling foam cells. Examples include silicone-based surfactants. Furthermore, inorganic fillers, flame retardants, etc. can be added as necessary. In addition, in the present invention, a third layer other than the layer of the present invention may be provided as necessary.

[Example] Next, the results of a comparative experiment on the soundproofing effects of the soundproofing interior material of the conventional structure and the soundproofing interior material of the present example will be shown.

As a conventional example, a laminate designed for 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 vibration damping material 20 was welded to this. The sound absorbing material layer 30 was made of resin felt and had a thickness of 15 mm. A carpet lined with a polyethylene resin layer was used as the surface sound insulation layer.

On the other hand, as the soundproof interior material of this example,
A laminate shown in FIG. 1 was used. The vehicle body panel 1, the asphalt vibration damping material 2, and the carpet 5 are the same as the soundproof interior material of the conventional structure shown in FIG.

3 is a solidified piece of urethane foam that is molded to follow the rib shape of the car body panel (steel plate) 1, heated to about 200℃, and then pressed into a predetermined shape. It is a material layer. 4 is a slab sheet of asphalt-urethane integrally foamed foam which is attached to the sound absorbing material layer.

When evaluating the soundproofing effect, vibration was applied to each base iron plate (10 in FIG. 5, 1 in FIG. 1), and the sound pressure level of solid sound generated from each sample was measured.

The results are shown in FIG.

From the above results, it was found that the sound pressure level of the present example was lower than that of the comparative example, and the soundproofing effect was excellent.

[Effects of the invention] As explained above, according to the invention, by providing the asphalt-urethane integral foam foam between the sound-absorbing material layer and the surface sound-insulating material layer, it is possible to almost change the thickness and weight of the sound-insulating material. No, 500Hz
The following sound insulation performance can be improved, and by molding the sound absorbing material layer to follow the rib shape of the vehicle body panel, it is possible to improve the flat feeling and further improve the sound insulation performance.

In the present invention, as the asphalt-urethane integral foam disposed in the second layer, a prepolymer made of asphalt and polyol/isocyanate is used. Compared to asphalt-urethane foams in which the foam is impregnated with asphalt, and monolithic foams made of asphalt, water emulsion, and water-soluble prepolymers, the soundproofing performance in the low frequency range is particularly good. be able to solve the problems faced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of the present invention;
FIG. 2 is a cross-sectional view of main parts showing another embodiment of the present invention;
Fig. 3 is a graph showing the relationship between frequency and normal incidence sound absorption coefficient, where curve B is the invention, curves A and C are comparative examples, Fig. 4 is a graph showing the measurement results of sound pressure level, and Figs. FIG. 6 is a sectional view of main parts showing a conventional example. DESCRIPTION OF SYMBOLS 1... Vehicle body panel, 2... Damping material, 3... Sound absorbing material layer, 4... Asphalt-urethane integrated foam layer, 5... Surface sound insulating layer.

Claims (1)

[Scope of utility model registration request] In the soundproof interior material for automobiles that is attached to the car body panel, the first layer is a sound absorbing material layer made of urethane foam or strips of urethane foam molded in a shape that follows the rib shape of the car body panel, and the second layer is asphalt and polyol. - A soundproof interior material for automobiles having a structure in which an asphalt-urethane integral foam made of a prepolymer made of isocyanate is sequentially laminated with a surface soundproof layer as the third layer.