Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Patent
1988-08-16
1990-05-15
Dawson, Robert A.
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
156 93, 156156, 156256, 206524, 220902, 264 452, 264 466, 264 469, B32B 3114, B32B 520
Patent
active
049255088
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a moldless process for manufacturing foamed articles composed of a foamed polyurethane body and a cover material enveloping integrally the body, without the use of any conventional mold.
2. Background Art
Many foamed articles such as vehicle seat cushions, head rests, arm rests and the like are generally manufactured through the use of molds, each cavity of which is configured in conformity to an outer contour of a final product to be desired. A cover or facing material such as fabric and natural or synthetic leather is set in the mold cavity by being laid along the entire inner surface of the mold cavity and shaped so as to follow the cavity inner surface. A liquefied foamable composition is poured to the inside of the cover material which has already set in the mold cavity, and allowed to foam and expand until it reaches to and becomes integral with the inner surface of the cover. Foaming composition exerts strong pressures through the cover material against the cavity wall, and thereby adheres firmly to and integrally with the inner surface of the cover.
It has been long believed that the molds used for manufacturing foamed articles must have strong and heavy metallic structures in order to endure the strong pressure caused by foaming of compositions and to assure an accurate outer configuration of the final product. Such molds however, are very expensive to manufacture and difficult to manipulate. And further such molds require large installing space. Additionally, even if different surface configurations are required for the final products, the cavity wall shape of the conventional molds cannot be easily altered to meet such requirements.
Although the foaming compositions produce strong pressure against the cover during foaming inside the cover, they can not perform to smooth and remove wrinkles and creases which have been formed in the cover fabric at the time of setting up in the mold. Accordingly, once wrinkles are formed in the cover at the time of setting, they can not have a chance to be smoothed or removed. Thus, the setting of the fabric was a very important procedure and the fabric had to be set in such an accurate and regulated manner that it might make intimate contact with the cavity inner surface without wrinkles. This required cumbersome and time-consuming manual labor.
Moreover, the cover placed in the conventional mold may easily move out of the proper setting position prior to pouring the foaming material. Even if the fabric can be once set accurately in the mold, this setting state is only provisional but not fixed. Accordingly, the cover fabric may easily get out of its proper position by vibrations or shocks applied to the mold. However, checking of the fabric setting state is very hard during the manufacturing process. Particularly, after the lid of the mold is closed, it is impossible to check how the fabric is set in the mold. Accordingly, subsequent pouring and foaming steps of the foamable composition must be proceeded without checking of fabric setting state, running the great risk of producing defective articles.
Another problem is that the foamable composition of the prior art required considerably long time period from pouring to completing the final curing of the composition, and therefore very long and vast production line was needed for accomplishing the manufacture of foamed articles and yet only low productivity was attained.
The prior mold manufacturing has further problems as follows. Vacuuming technique is usually employed with perforations through the cavity wall in order to attract and bring the fabric into intimate contact with the cavity surface. Thus, the fabric itself must be of impermeable nature to assure attracting effect on the fabric. In this case the resultant products including arm rests, seat cushions and the like become uncomfortable because they are sticky to the touch with sweat or moisture attached and remaining on the outer impermeable surface thereof.
DISCLOSURE OF THE INVENTION
Accord
REFERENCES:
patent: 3485347 (1969-12-01), McGill et al.
patent: 3641725 (1972-02-01), Grisell
patent: 3952082 (1976-04-01), Arnaud
patent: 4267927 (1981-05-01), English
Goto Fumio
Ogawa Taro
Dawson Robert A.
Namba Press Works Co. Ltd.
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