Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-11-01
2004-02-24
Aftergut, Jeff H. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S222000, C156S309600, C156S309900
Reexamination Certificate
active
06695939
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. 11-313614 filed on Nov. 4, 2000 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing an interior trim material. More particularly, the present invention relates to a method of producing an interior trim material, such as a ceiling materials or a door trim for use in automobiles, in which a skin material is bonded to a substrate,.
2. Discussion of Related Art
Conventionally, an interior trim material comprised of a rigid substrate and a skin material bonded to at least one surface thereof has been widely used in the interior or vehicle compartment of an automobile.
In this case, inorganic fibers and thermoplastic fibers are mainly used for producing the substrate. The inorganic fibers provide certain rigidity and dimensional stability, and the thermoplastic fibers provide certain formability, while the skin material provides a certain design quality.
A known example of method (hereinafter referred to as “known method 1”) of producing an interior trim material having the above-described substrate and the skin material bonded to the surface thereof includes three processes, i.e., a process of producing a substrate, a process of tentatively bonding a skin material to the substrate, and a forming process.
In the substrate production process of the known method 1, the substrate is prepared by laminating a thermoplastic resin film or films onto either one or both of the opposite surfaces of a mat-like fiber structure mainly formed from inorganic fibers containing thermoplastic fibers. This substrate is then fed onto an endless belt formed from a Teflon sheet that is bonded to the substrate when the thermoplastic resin film is in a molten state but not bonded thereto when the same film is not in a molten state, and is then heated in a furnace.
Subsequently, the substrate thus heated is compressed under pressure by a pressing portion on the endless belt so that the mat-like fiber structure is impregnated with the thermoplastic resin film. At the same time, the inorganic fibers contained in the mat-like fiber structure are firmly bonded together by means of the thermoplastic fibers contained in the mat-like fiber structure. The substrate thus compressed under pressure is thereafter naturally or forcibly expanded so as to restore its original thickness, and the cooled at a cooling portion on the endless belt. In this manner, a substrate is produced in which inorganic fibers are bonded together by thermoplastic resin and thermoplastic fibers.
In the next process of bonding the skin material, the substrate produced in the above step is cut into a suitable size, and a skin material is laminated on the cut piece of the substrate, and locally melted by heat so as to be tentatively bonded to the substrate.
Finally, in the forming process, the substrate to which the skin material has been tentatively bonded is reheated in the furnace so that the thermoplastic fibers and thermoplastic resin are melted. A cold press machine is then used to form the substrate with the skin material into a desired shape, thereby to provide an interior trim material consisting of the substrate and the skin material bonded to the substrate.
Japanese Patent Laid-Open Publication No. HEI 8-80601 discloses a method in which a skin material as well as a substrate is fed onto an endless belt in the substrate production process as described above, thereby eliminating the process of tentatively bonding the skin material to the substrate, and a flat composite sheet with the skin material can be produced in a single process step.
According to a method of producing an interior trim material as disclosed in Japanese Patent Laid-Open Publication No. 10-315396 (hereinafter referred to as the “known method 2”), a mat-like fiber structure formed from thermoplastic fibers and glass fibers is prepared, and hot air having a temperature high enough to melt the thermoplastic fibers is caused to pass through the fiber structure from the front side to the back side thereof, thereby providing a substrate in which the density distribution of the thermoplastic resin has been thus varied. Then, a skin material with thermoplastic resin formed on its back surface, which has been heated such that the thermoplastic resin is given certain plasticity, is laminated on a surface of the substrate provided in the above manner. The thus laminated skin material and substrate are then formed into a desired shape by press molding using a forming die, so as to form a substrate in which the glass fibers are bonded together by thermoplastic fibers, while at the same time bonding the skin material to the substrate, thereby to produce an interior trim material.
In the known method 1 as described above, the substrate is heated in the furnace so that the thermoplastic fibers and thermoplastic resin are melted, and the substrate thus heated is compressed under pressure so that the inorganic fibers are firmly bonded together by the thermoplastic fibers and thermoplastic resin, whereby the resulting substrate is given rigidity.
In the known method 1, a series of steps included in the substrate production process are carried out by use of the endless belt. This eliminates such a problem that melted thermoplastic resin sticks to local parts of a press mold or die, or the like, when the substrate is compressed under pressure, resulting in a failure to transport the substrate to the following process step. Thus, the substrate can be favorably produced with high reliability and efficiency.
The endless belt used in the known method 1, however, is required to have sufficiently high heat resistance, durability, and rigidity, and therefore cannot be suitably used for forming interior trim materials having complicated shapes. Thus, in the process step of impregnating the mat-like fiber structure with the thermoplastic resin film, the heated substrate material is compressed under pressure, only to be formed into the shape of a flat plate or sheet. Namely, the substrate can be formed only in the shape of a flat plate or sheet.
In order to form a substrate into a desired shape other than the flat shape, therefore, it is necessary to re-heat the substrate to soften the thermoplastic fibers and thermoplastic resin, so as to form the substrate into the desired shape in another process without using an endless belt, for example, in the forming process of the known method 1. If the substrate, in which organic fibers have been firmly bonded together by thermoplastic resin and thermoplastic fibers through the process of impregnating the substrate with the thermoplastic resin, is reheated, however, the bonding strength of the fibers in the substrate is weakened, and the strength of the resulting substrate is reduced. If the density (mass per unit area) of the substrate is increased so as to ensure a required strength of the substrate, the weight of the substrate may be undesirably increased, and the production cost may also be undesirably increased.
In the known method 2 as described above, on the other hand, only one heating step is required in the whole manufacturing process beginning with the production of the substrate and ending with the production of the interior trim material to which the skin material is bonded.
In the method as described above, the substrate through which hot air has been passed and the skin material backed with the melted thermoplastic resin and laminated on the substrate are formed directly into a desired shape using a suitable die. In order to provide sufficiently high bonding strength with the skin material by impregnating the substrate with the backing resin, the die clearance of the forming die needs to be reduced. This may result in a reduction in the substrate thickness, and insufficient rigidity due to the reduced substrate thickness. If the die clearance of the forming dies is increased, on the contrary, the compressi
Kato Shuichi
Nakamura Tetsuya
Ogura Shuji
Aftergut Jeff H.
Musser Barbara J
Oliff & Berridg,e PLC
Toyoda Boshoku Corporation
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