Stock material or miscellaneous articles – Sheet including cover or casing – Foamed or expanded material encased
Patent
1989-12-28
1992-03-03
Van Balen, William J.
Stock material or miscellaneous articles
Sheet including cover or casing
Foamed or expanded material encased
428 76, 4283155, 4283159, 4283166, B32B 326
Patent
active
050931750
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an integrally foamed article having a threefold-laminated cover material, and more particularly to an integrally foamed article covered and enclosed by a threefold-laminated cover material, which is composed of an outermost permeable cover fabric, an intermediate slab foam and an innermost shielding film. An integrally foamed article of the invention can be applied to various products including vehicle seats, seat cushions, headrests, stuffed toys or dolls, and the like.
BACKGROUND ART
There is a well known process for manufacturing an integrally foamed article including:
a) providing a permeable cover fabric,
b) configuring the permeable fabric into a substantially closed configuration which is substantially corresponding to a final contour of a desired final product, and
c) pouring a liquid foamable mixture such as liquid polyurethane mixture into said closed configuration causing the mixture to foam and expand in situ and to be integral with the interior surface of said cover fabric. In this instance, the cover fabric must be of permeable nature in order to expell gases produced during foaming of the mixture and air entrapped inside the cover fabric.
The permeable cover fabric, however, has many drawbacks in that the liquid foamable mixture poured onto the inner surface of the cover fabric penetrates into the cover fabric itself and leaks out of the cover fabric so that any cured and hardened spots or areas are formed locally on the surface of the fabric to spoil the appearance of the final product, to make stiffened touch on the surface of the foamed article, and to lower quality of the foamed article. To avoid these defects, French patent No. 2,470,566 to Societe Industrielle Bertrand Faure, Jan. 13, 1984 discloses a relief method as illustrated in FIG. 5 of the attached drawings. In this method, permeable fabric 1 of natural or synthetic fibers and thin layer of synthetic foam 2 adhered thereto compose a cover material into which highly catalyzed reactive polyurethane stock is directly poured while it is still in the flowable state though it begins its chemical reaction so as to foam and expand to form a body foam 3. It is said in this French patent that the body foam 3 penetrates slightly into the thin foam 2 to form a "superficial layer" which provides strong bonding between the body 3 and the thin layer 2, yet allowing the layer 2 to be permeable, and the "superficial layer" never reaches the cover fabric 1 nor causes locally stiffened areas to be produced therein.
According to the above French patent, the "superficial layer" is formed by the fact that the poured mixture, while rapidly changing from liquid state to creamy state, penetrates only "superficially" into the thin foam 2 to form "stiffened layer" sufficiently hardened to assure good bonding between the foam body 3 and the thin foam 2.
Thus, the French patent alleges that it can obviate such problems heretofore encountered in the integrally foamed product by direct pouring method as leaking out of foamable mixture through cover fabric, stiffened touch and spoiled appearance of the resultant product.
It is noted, however, that the existence of said stiffened "superficial layer" between the body foam and the thin foam layer of the product actually provides stiff and uncomfortable touch when one contacts or presses the outer surface of the product in an actual use thereof.
Another problem resides in that poured creamy foamable mixture penetrates partially into the thin foam layer 2 to cause flow resistance to the poured material to be larger and fluidity of the material to be lowered. Thus, the teachings in the aforementioned French patent is not suited particularly to manufacturing of thin foamed products because the foamable material poured into a relatively thin or restricted space hardly flows therethrough to reach eventurally the overall length of the product to be formed so that defective portions may occur not attaining prescribed thickness of foam.
Furthermore, the foamable material poure
REFERENCES:
patent: 3130505 (1964-04-01), Markevitch
patent: 4520517 (1985-06-01), Ahlm
patent: 4824719 (1989-04-01), Creyf et al.
Goto Fumio
Ogawa Taro
Namba Press Works Co. Ltd.
Van Balen William J.
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