Method for mounting a shock absorbing and protecting material

Abstract: A shock absorbing material (1) for automobiles, having extremely good shock absorbing properties, capable of absorbing shocks applied to a passenger in a car at the time of a crash, or the like, and reducing the head injury criteria, comprising a rigid polyurethane foam having a compression stress of 3 kg/cm 2 or more, with concavities arranged on at least one planar surface. In order to mount the head protecting material to a ceiling material (2), a trim, a car body, or the like, easily and securely, the head protecting material (1) is mounted to the ceiling material (1), or the like, with an adhesive sheet (3) comprising a base material (3A) made of a foam material with an adhesive layer (3B) formed thereon.

Description: The present invention relates to a method for easily and securely mounting a shock absorbing material to an automobile body and to an automobile including such a shock absorbing material, the shock absorbing material being mounted in particular for improving safety by absorbing and reducing shock energy imparted to the heads or other body parts of passengers in the car interior at the time of a crash. These days, in order to improve automobile safety, head protecting material for damping shocks to the head of a passenger has been mounted to a car body inner wall, a ceiling material, a trim, or the like. The head protecting material, in general, is a strip-like member about 60 mm × 450 mm × 20 mm. Conventionally, those comprising a rigid polyurethane foam, those comprising a bead-like foamed member of a polypropylene, polyethylene or polyolefin resin, resin ribs of an ABS, polypropylene, polyethylene, polyolefin, or the like, have been provided. These head protecting materials are made of a material with a relatively high hardness. In mounting such a head protecting material to, for example, the rear surface of a ceiling material of an automobile, it is mounted along the sides of the ceiling material 10 corresponding to the seat position of passengers as shown in FIG. 3A as 11A, 11B, 11C, 11D. As shown in FIG. 3B (enlarged view of the cross-section taken on the line XIIIB-XIIIB of FIG. 3A), an adhesive tape 12 or an adhesive is used for mounting. Conventionally, as the adhesive tape 12, one comprising a base material of non-woven fabric, paper, plastic film, or the like, and an adhesive material applied thereon for forming an adhesive layer has been used. Moreover, as the adhesive, a hot melt adhesive, a solvent adhesive, or an aqueous adhesive has been used. The conventional head protecting material mounting method involves the following problems. Although the mounting operation itself can be easier by mounting with an adhesive tape compared with the case of using an adhesive, since the head protecting material is made of a relatively hard material and thus cannot follow the deformation of the mounted surface, the head protecting material can easily peel and fall off. That is, if the head protecting material is mounted to a part of a flat and wide area like the rear surface of the ceiling material, when the part is deformed by twisting during transportation, the adhesive surface peels and falls off due to inability to conform to the deformations of the hard the head protecting material. Moreover, in assembling a part mounted with the head protecting material, such as the ceiling material with a car body, since the head protecting material projects from the part, such as the ceiling material for the thickness thereof as a level difference, the projecting head protecting material contacts the car body, or the like, the head protecting material falls off from the part also in this case due to inability of the adhesive surface to follow the deformation for the hardness of the head protecting material. On the other hand, in the case of mounting with an adhesive, since the part needs to be left for about one day after application of an adhesive in a method of using an aqueous adhesive, a long mounting operation time is required, and thus it is not practical. Moreover, since the head protecting material needs to be fixed and held for 20 to 30 seconds after application when a hot melt adhesive is used, and an standing time is required after application of an adhesive in the case of a solvent adhesive, both require a large number of bonding steps, and thus are difficult to execute. Moreover, since both the hot melt adhesive and the solvent adhesive become adhesive by hardening and the adhered to surface becomes hard, the adhered to surface cannot conform to the deformation when there is deformation during transportation or a crash of the car body so that a problem arises in which the head protecting material falls off, as in the case of the adhesive tape. WO95/06691 discloses conformable pressure sensitive adhesive tapes which comprise a layer of polymeric foam in the backing and may be adhered firmly to a substrate and thereafter removed therefrom after only being stretched at an angle no greater than about 35° from the surface of the substrate. US 4,364,972 discloses pressure sensitive adhesive tape which has both high adhesion and high cohesion values and adheres strongly to automotive paints and to rubber or plastic foam layers for adhering plastic molding strips to the sides of automobiles. An aim of the present invention is to provide a method for mounting a protecting material to a ceiling material, easily and securely. The present invention provides a method for mounting a stock absorbing material according to claim 1. With the adhesive sheet having a foam material as the base material, peeling off or falling off of the protecting material can be prevented due to deformation of the foam material provided as the base material. In the present invention, it is preferable that the density of the foam material comprising the base material of the adhesive sheet is 0.005 to 0.5 g/cm 3 , and the base material thickness is 0.5 to 5 mm The present invention also provides an automobile according to claim 7. Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:- FIG. 1 is a cross-sectional view showing an embodiment of a method for mounting a protecting material according to the present invention; FIGS. 2A to 2D are plan views showing embodiments of attaching an adhesive tape; and FIG. 3A is a perspective view showing an arrangement of mounting a head protecting material to a ceiling material; and FIG. 3B is an enlarged cross-sectional view taken on the line XIIIB-XIIIB of FIG. 3A. Hereinafter embodiments of the present invention will be explained in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a method for mounting a protecting material according to the present invention. FIGS. 2A to 2D are plan views showing embodiments of attaching an adhesive tape. As shown in FIG. 1, in the present invention, an adhesive sheet (in FIG. 1, adhesive tape 3) comprising a base material 3A made of a foam material with an adhesive layer 3B formed thereon is used for mounting a head protecting material 1 onto a ceiling material 2. As the foam material comprising the base material of the adhesive sheet to be used in the present invention, various foam materials, such as polyolefin resin foams including soft polyurethane foam, polypropylene, polyethylene, or the like, a foam rubber, or the like may be mentioned. As to the density thereof, it is desirably in the range of 0.005 to 0.5 g/cm 3 , in particular, 0.005 to 0.2 g/cm 3 . That is, since a foam material with a high density of more than 0.5 g/cm 3 cannot conform to deformation due to the hardness thereof, the falling off preventing effect of the head protecting material cannot be sufficiently obtained. On the other hand, a low density foam material with a density less than 0.005 g/cm 3 can be easily ruptured or damaged by handling since the strength of the foam material is low, and thus it is not practical. Moreover, the thickness of the base material comprising the foam material is preferably in the range of 0.5 to 5 mm. That is, a thin base material with a thickness of less than 0.5 mm cannot sufficiently yield the effects of preventing the falling off caused by the base material deformation of the head protecting material. Furthermore, since the clearance of the parts is set to about 5 mm or less in an ordinary car body, with a base substrate having a thickness of more than 5 mm, the adhesive sheet portion is thicker than the clearance so that the head protecting material can fall off by contact with the car body during assembling with the car body, or the head protecting material contacts with other parts, generating strange noises, and thus it is not preferable. Moreover, in the case of a base material having a thickness of more than 5 mm, when a shock is applied to the head protecting material mounted with the adhesive sheet, the base material of the adhesive sheet can be substantially deformed depending on the direction of the shock so as to generate displacement of the head protecting material, and thus the initial load necessary for protecting the head from shock cannot be obtained, and the head protecting material cannot perform the function thereof. In general, since shocks may be applied from various directions to the head protecting material, it is extremely important to ensure prevention of such displacement in order to protect the head. As to the adhesive material of the adhesive layer to be formed on the base material, an ordinary adhesive material, such as acrylic, rubber, of the like, can be used. In general, the adhesive layer is formed with such an adhesive material at a thickness of about 0.01 to 1 mm. In mounting the head protecting material to a ceiling material, or the like, with such an adhesive sheet, the method for attaching the adhesive sheet is not particularly limited, but a band-like adhesive tape 3 can be attached in the longitudinal direction of the head protecting material 1 as shown in FIG. 2A, or an adhesive tape 3 cut in a short length can be attached at a plurality of points on the head protecting material 1, as shown in FIGS. 2B and 2C. Moreover, as shown in FIG. 2D, an adhesive tape 3 can be attached according to the shape of the head protecting material 1 with an irregular shape. In the present invention, a band-like adhesive tape can be used accordingly as the adhesive sheet, or a small sticker-like adhesive sheet of a quadrilateral shape, circular shape, or the like, can be used. It can be selected and used optionally according to the shape, size, the shape of the part to be mounted, or the like, of the head protecting material. Hereinafter, a method for mounting a protecting material according to the present invention will be explained more specifically with reference to an example. Example 1 Ahead protecting material made of a rigid polyurethane foam 60 mm × 450 mm × 20 mm with an adhesive tape comprising a base material having a thickness of 3 mm made of a soft polyurethane foam with a 0.02 g/cm 3 density having an acrylic adhesive material adhesive layer (thickness: 0.06 mm) formed on both sides thereof, attached as shown in FIG. 2A, was mounted to a ceiling material for automobiles at the position shown in FIG. 3A. After mounting the head protecting material, the ceiling material was transported and assembled into a car body. When a head protecting material was mounted with an adhesive tape comprising a base material such as non-woven fabric, paper, plastic film, or the like, with an adhesive material applied thereon for forming an adhesive layer, falling off of the head protecting material occurred at the time of transportation and assembly. However, in this embodiment, even when the ceiling material was deformed during transportation or impact with another part at the time of assembly, the head protecting material was adhered firmly without peeling off or falling off. As is apparent from the above-mentioned Example 1 according to the present invention, in mounting a protecting material such as a head protecting material using an adhesive tape, capable of being easily and inexpensively mounted, with superior mounting operability, without the need for fixing time or holding time, deformation of the part mounted with the protecting material during handling, or peeling off or falling off of the protecting material at the time of impact by another part can be prevented. Therefore, according to the present invention, a protecting material can be mounted easily, securely, and firmly to a part, which can be drastically deformed or have shock applied thereto, namely a ceiling material of an automobile.

Claims: A method for mounting a shock absorbing material (1), the method comprising the steps of adhering the shock absorbing material (1) to a surface of a ceiling material (2) of an automobile by an adhesive sheet (3), wherein the adhesive sheet (3) comprises a base foam material (3A) and an adhesive layer (3B) formed thereon on both sides of the base foam material (3A), and assembling the adhered assembly, comprising ceiling material (2), adhesive sheet (3) and shock absorbing material (1), into a body of said automobile. The method for mounting a shock absorbing material (1) according to claim 1, wherein the density of the base foam material (3A) is 0.005 to 0.5 g/cm 3 , and thickness of the base foam material (3A) is 0.5 to 5 mm. The method for mounting a shock absorbing material (1) according to any one of claims 1 or 2, wherein the base foam material (3A) is a soft polyurethane foam, a polyolefin resin foam, or a foam rubber. The method for mounting a shock absorbing material (1) according to any one of claims 1 to 3, wherein the adhesive layer (3B) is an acrylic adhesive material or a rubber adhesive material. The method for mounting a shock absorbing material (1) according to any one of claims 1 to 4, wherein the density of the base foam material (3A) is 0.005 to 0.2 g/cm 3 . The method for mounting a shock absorbing material (1) according to any one of claims 1 to 5, wherein the thickness of the adhesive layer (3B) is 0.01 to 1 mm. An automobile including a shock absorbing material (1) mounted to a ceiling material (2) of said automobile by an adhesive sheet (3) comprising a base foam material (3A) and an adhesive layer (3B) formed thereon on both sides of the base foam material (3A), said shock absorbing material (1), adhesive sheet (3) and ceiling material forming an adhered assembly which is assembled into a body of the automobile. An automobile according to claim 7 wherein the density of the base foam material (3A) is 0.005 to 0.5 g/cm 3 , and thickness of the base foam material (3A) is 0.5 to 5 mm. An automobile according to claim 7 or claim 8, wherein the base foam material (3A) is a soft polyurethane foam, a polyolefin resin foam, or a foam rubber. An automobile according to any one of claims 7 to 9, wherein the adhesive layer (3B) is an acrylic adhesive material or a rubber adhesive material. An automobile according to any one of claims 7 to 10, wherein the density of the base foam material (3A) is 0.005 to 0.2 g/cm 3 . An automobile according to any one of claims 7 to 11, wherein the thickness of the adhesive layer (3B) is 0.01 to 1 mm.

Inventors: HORIMATSU TOSHIYUKI, TABATA KEIICHIRO, TADA SHIN, HORIMATSU,TOSHIYUKI, TABATA,KEIICHIRO, TADA, SHIN, Tabata,Keiichiro, Yokohama Plant Bridgestone Corp., Tada, Shin, Yokohama Plant Bridgestone Corp.
Applicants: BRIDGESTONE CORP, BRIDGESTONE CORPORATION
Application year: 1999
Main classification: B60R21
IPC codes: F16F7, B60R21, C09J7