Stock material or miscellaneous articles – Structurally defined web or sheet – Including sheet or component perpendicular to plane of web...
Reexamination Certificate
1997-03-24
2001-02-06
Watkins, III, William P. (Department: 1772)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including sheet or component perpendicular to plane of web...
C428S133000, C428S166000, C428S178000, C428S223000, C428S099000, C428S139000, C428S137000, C156S145000, C156S147000, C156S309600, C442S394000, C442S286000
Reexamination Certificate
active
06183838
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to protective packaging or cushioning materials and more particularly to a composite protective or cushioning material and method of forming such a composite material.
BACKGROUND OF THE INVENTION
Protective and cushioning materials have a wide variety of uses in the shipping and handling of various and sundry articles and in the protection of the surfaces of such items. A particularly popular form of a protective and cushioning material is an air cellular material in which two layers of plastic film are laminated together and have a multiplicity of gas filled cavities therebetween. This air cellular material provides excellent cushioning characteristics and is relatively inexpensive.
Such air cellular material does, however, have certain deficiencies or disadvantages which limit the applicability and use thereof. One such deficiency is the surface characteristics of this air cellular material. Since the air cellular material is formed of plastic film, the surface characteristics are limited and can be considered relatively abrasive and undesirable for some uses. Also, the air cellular material is susceptible to penetration by sharp or pointed objects and to rupture of the air bubbles by those and other objects with a concomitant loss in cushioning capacity.
It has been previously proposed to improve the characteristics of such air cellular material by producing a composite material in which a third layer is combined with the air cellular material. An example of such a composite material is disclosed in U.S. Pat. No. 4,698,109, issued Oct. 6, 1987. The composite material disclosed in this patent includes an air cellular material to one side of which is fusion bonded a non-woven, fibrous layer. U.S. Pat. No. 4,698,109 clearly discloses that, to achieve such fusion bonding, i.e. heat lamination or heat sealing, the third layer must be formed of a material which is compatible with the plastic film forming the layers of the air cellular material, i.e. a polymer which can be fusion bonded to the polymer of the plastic film of the air cellular material. Specifically, this patent states that a fibrous material formed of polyethylene or polypropylene fibers would be required.
While providing certain advantages over plain air cellular material alone, this prior composite material was very limited in the surface and other characteristics which could be provided since only compatible materials could be used in forming the third layer. There is a wide variety of incompatible materials which would provide highly desirable characteristics in such a composite material which have not been used heretofore because there was no known, cost-effective way to incorporate such incompatible materials in a composite material with the air cellular material.
SUMMARY OF THE INVENTION
With the foregoing in mind, it is an object of the present invention to provide a composite material including an air cellular material and a method of forming the same which does not have the deficiencies, disadvantages and limitations of prior such composite materials.
This object of the present invention is achieved by providing a composite material including an air cellular material formed of first and second layers of plastic film laminated together and defining a multiplicity of gas filled cavities or bubbles therebetween and a third layer of material mechanically bonded to one of the first and second layers of plastic film. Since the third layer is mechanically bonded to the air cellular material, as opposed to fusion bonded, there is no requirement that the third layer be formed of a compatible material. Therefore, the third layer may be formed of a wide variety of materials, almost without limitation.
The third layer may be mechanically bonded to the air cellular material in several different ways. For example, if the third layer is formed of a fibrous material, the surface thereof contiguous to the contiguous surface of the air cellular material will have fibers projecting outwardly therefrom. These projecting fibers are embedded in the contiguous surface of the air cellular material by softening the plastic film, causing the projecting fibers to penetrate thereinto and then causing the plastic film to harden. Such projecting fibers are entrapped therein and interlock the third layer and the air cellular material. With other types of materials which do not normally have projections thereon, such projections can be provided in any number of known ways.
Alternatively, the third layer may be mechanically bonded to the air cellular material by providing cavities in the contiguous surface of the third layer and causing the plastic of the contiguous surface of the air cellular material to flow into such cavities and to harden therein. Therefore, the third layer is interlocked to the air cellular material.
REFERENCES:
patent: 3468311 (1969-09-01), Gallagher
patent: 4181548 (1980-01-01), Weingarven
patent: 4313993 (1982-02-01), McGlory
patent: 4314865 (1982-02-01), Ottaviano
patent: 4412879 (1983-11-01), Ottaviano
patent: 4614000 (1986-09-01), Mayer
patent: 4628549 (1986-12-01), Lazar
patent: 4698109 (1987-10-01), Lazar
patent: 4957805 (1990-09-01), Biggs et al.
patent: 5084324 (1992-01-01), Schirmer
Alston & Bird LLP
Sealed Air Corporation
Watkins III William P.
LandOfFree
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