JP4623541B2 - Sound absorbing material for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminated body, and more particularly to a laminated body suitable as a vehicle sound absorbing material.
[0002]
[Prior art]
A vehicle is provided with a sound-absorbing material for reducing external noise mainly due to engine sound. Conventionally, as the sound absorbing material, an outer layer is laminated on both sides of an inner layer made of polyurethane foam via a glass fiber layer impregnated with a binder, the laminated members are heated and compressed by a heat roller, and each member is cured by curing the binder. A laminated body in which the shape is integrated and the shape is fixed is known.
[0003]
By the way, the above-mentioned sound absorbing material for vehicles has been required not only to absorb sound but also to be lightweight from the viewpoint of improving fuel efficiency, and also to be recyclable from the viewpoint of recent waste reduction and resource saving.
[0004]
However, the conventional laminate including glass fibers is heavy because it contains glass fibers, and the weight reduction is not easy. Further, if the pulverization or crushing process is performed in order to recycle, there is a problem that the abrasion of the blade in the pulverizer is remarkably caused by the glass fiber, and the glass fiber is scattered in the air and the working environment is deteriorated. Furthermore, the recycled product becomes heavier due to the mixing of the glass fiber, which may not be preferable depending on the use of the recycled product. Moreover, even if the laminated body is incinerated, there is a problem that the glass remains and is difficult to process.
[0005]
[Problems to be solved by the invention]
The present invention has been proposed in view of the above points, and provides a sound absorbing material for a vehicle which is suitable for recycling and is made of a lightweight laminate without impairing sound absorbing property, shape retaining property and rigidity. is there.
[0006]
[Means for Solving the Problems]
The invention of claim 1 is a laminate in which an outer layer is laminated and integrated on both sides of an inner layer made of a foam through an intermediate layer, the inner layer being a polyurethane foam having flame retardancy and breathability, and the intermediate layer being Spunbond nonwoven fabric of polypropylene fiber, the outer layer is made of a material that is flame retardant and can be impregnated with a molten resin, the molten resin of the polypropylene fiber constituting the intermediate layer is impregnated and cured in the outer layer, and the polypropylene fiber is welded Thus, the present invention relates to a sound absorbing material for a vehicle used around an engine composed of a five-layer laminate in which an inner layer, an intermediate layer and an outer layer are integrated.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a laminate according to one embodiment of the present invention.
[0008]
A laminated body 10 according to an embodiment of the present invention shown in FIG. 1 is used as a sound absorbing material adhered to the back surface of a bonnet of a vehicle, and has an outer layer 13 on both sides of an inner layer 11 via intermediate layers 12. Is formed by stacking and integrating.
[0009]
The inner layer 11 is made of a foam. As the foam constituting the inner layer 11, a polyurethane foam having air permeability is preferable because of excellent sound absorption and light weight. Examples of the polyurethane foam having air permeability include a soft polyurethane foam mainly having an open cell structure.
[0010]
Moreover, since the bonnet of the vehicle to which this laminated body 10 is stuck becomes high temperature, the foam of the inner layer 11 is preferably flame retardant. Flame retardant flexible polyurethane with flame retardancy imparted or enhanced flame retardancy by adding a flame retardant comprising an organic halogen compound or other flame retardant treatment as the flame retardant foam Foam is preferred.
[0011]
Furthermore, the foam which comprises the said inner layer 11 can be selected from the wide range in which ventilation resistance (JISK6400 conformity) exists in 5-150cm < ³ > / (cm < ² > * sec). Conventionally, as foams for sound absorption, those having a ventilation resistance exceeding 100 cm ³ / (cm ² · sec) have been considered to be unsuitable because the sound absorption effect is low, but in the present invention, in addition to the outer layer 13 Since the intermediate layer 12 made of polypropylene fiber is provided, by adjusting the basis weight of the intermediate layer 12, excellent sound absorption characteristics can be obtained even for the foam having a ventilation resistance of 100 to 150 cm ³ / (cm ² · sec). It became so.
[0012]
The mid layer 12 is made of a known polypropylene fiber. The polypropylene fiber is melted when the inner layer 11, the intermediate layer 12 and the outer layer 13 are laminated and the laminate 10 is manufactured by hot pressing, and the layers are welded and integrated with the molten resin (molten polypropylene resin). The rigidity of the laminated body 10 is increased. In addition, the polypropylene fiber is preferably a nonwoven fabric from the viewpoint of easy handling of the intermediate layer 12 at the time of manufacturing the laminate 10 and an increase in rigidity of the laminate 10, and among them, a spunbond nonwoven fabric made of polypropylene manufactured by the spunbond method is preferable. . This spun pond non-woven fabric is not only excellent in light weight, but also does not stretch due to moisture, and since it is made of continuous fibers, there is no fraying at the end, so it is suitable for this laminate 10 used as a sound absorbing material for vehicles. It is. Examples of such a polypropylene spunbond nonwoven fabric include a basis weight of 40 g / m ² and a trade name: STRATEC RW2040 (manufactured by Idemitsu Petrochemical Co., Ltd.).
[0013]
The outer layer 13 is mainly for enhancing the rigidity of the laminate 10 and protecting the surface, and is made of a material that can be impregnated with a molten resin. If the material can be impregnated with the molten resin in this way, the polypropylene fiber of the intermediate layer 12 is melted and the outer layer 13 is impregnated into the outer layer 13 and cured at the time of hot pressing performed in the production of the laminate 10. Therefore, the obtained laminate 10 has high rigidity, and the laminate 10 having sufficiently high rigidity can be obtained without using glass fibers.
[0014]
The outer layer 13 is preferably a nonwoven fabric. As an example of the nonwoven fabric which comprises this outer layer 13, what was comprised with the fiber which consists of polymers, such as polyolefin, polyester, polyamide, polyvinyl chloride, an acrylic copolymer, a polystyrene, a polyurethane, is mentioned. Furthermore, the outer layer 13 preferably has flame retardancy. Examples of the flame retardant outer layer 13 include a nonwoven fabric subjected to a known flame retardant treatment with a chlorinated organic phosphorus compound or the like. As a flame retardant nonwoven fabric that is commercially available, basis weight 50 g / ^{m 2,} trade name RF1050 (manufactured by Asahi Kasei), basis weight 40 g / ^{m 2,} can be mentioned trade name Rasutan (manufactured by Asahi Kasei).
[0015]
Next, a manufacturing example of the laminate 10 will be described. The laminated body 10 is manufactured by laminating the outer layer 13 on both sides of the inner layer 11 via the intermediate layer 12 and hot pressing the outer layer 13 from the outer surface side of the inner layer 11 with a hot plate or the like having a required shape. . The hot press temperature in that case is normally 150-210 degreeC.
[0016]
During the hot pressing, the polypropylene fibers of the intermediate layer 12 located between the inner layer 11 and the outer layer 13 are melted, and the molten polypropylene resin is welded to the outer layer 13 and the inner layer 11, whereby the inner layer 11, the intermediate layer 12, and the outer layer 13. Are integrated into the laminate 10 fixed in a required shape. Since the molten polypropylene resin in which the intermediate layer 12 is melted has a higher viscosity than a conventionally used liquid binder, the degree of impregnation into the inner layer 11 is low. In addition, since the polypropylene fibers of the intermediate layer 12 are not melted during the period from the lamination of the respective layers to before the hot pressing, there is no possibility of impregnation into the inner layer 11. For these reasons, the laminated body 10 manufactured by the hot pressing is less likely to cause a decrease in sound absorption of the inner layer 11 due to the impregnation and hardening of the molten polypropylene resin into the inner layer 11, and can exhibit good sound absorption.
[0017]
Furthermore, the foam of the inner layer 11 is less likely to be impregnated with the molten polypropylene resin in the inner layer 11 if the pores are reduced in the range of the airflow resistance of 5 to 150 cm ³ / (cm ² · sec), Decrease in sound absorption can be prevented and good sound absorption can be obtained.
[0018]
Further, since the molten polypropylene resin is welded to the inner layer 11 and the outer layer 13 and hardened, the resulting laminate 10 has high rigidity. Furthermore, if the outer layer 13 is impregnated with molten resin, the molten polypropylene resin is impregnated into the outer layer 13 and hardened, so that the rigidity of the outer layer 13 is improved and the rigidity of the entire laminate 10 is also greatly increased. To do.
[0019]
Furthermore, if the polyurethane foam 31 constituting the inner layer 11 and the nonwoven fabric 33 constituting the outer layer 13 are flame retardant, the laminate 10 can be used in a high temperature environment such as a vehicle bonnet. This is even more preferable.
[0020]
【The invention's effect】
As illustrated and described above, according to the vehicle sound absorbing material of claim 1, an intermediate layer made of polypropylene fiber is used instead of the conventional glass fiber, and the inner layer, the intermediate layer, and the outer layer are integrated by welding the polypropylene fiber. Since it is not necessary to use glass fiber, it is suitable for recycling, and further, it does not impair sound absorption, shape retention and rigidity, and is excellent in light weight. Therefore, the laminate of the present invention is suitable for a sound absorbing material for vehicles that is required to be lightweight.
[0021]
According to the vehicle sound absorbing material according to claim 1, since the intermediate layer is made of polypropylene fiber nonwoven, it is easy to manufacture the vehicle sound absorption material, yet easily increase the rigidity of the vehicle sound absorbing material.
[0022]
Further, according to the invention of claim 1 , the inner layer is made of a breathable polyurethane foam, the outer layer is made of a material that can be impregnated with molten resin, and the molten resin of polypropylene fibers constituting the intermediate layer is impregnated and cured in the outer layer. Therefore, the rigidity of the vehicle sound absorbing material can be sufficiently increased without using glass fibers.
[0023]
Furthermore, according to the invention of claim 1 , since the inner layer and the outer layer have flame retardancy, a sound absorbing material for a vehicle suitable as a sound absorbing material around the engine that is the highest temperature in the vehicle body can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a vehicular sound absorber made of a laminate according to an embodiment of the present invention.
[Explanation of symbols]
10 Laminated body 11 Inner layer 12 Intermediate layer 13 Outer layer

Claims (1)

In the laminate in which the outer layer is laminated and integrated on both sides of the inner layer made of foam via an intermediate layer,
The inner layer is made of a polyurethane foam having flame retardancy and breathability, the intermediate layer is made of a polypropylene fiber spunbond nonwoven fabric, the outer layer is made of a flame retardant material that can be impregnated with a molten resin,
The molten resin of polypropylene fiber constituting the intermediate layer is impregnated and cured in the outer layer, and is used around an engine composed of a five-layer laminate in which the inner layer, the intermediate layer and the outer layer are integrated by welding of the polypropylene fiber. Sound absorbing material for vehicles .

Images