Bilayer adhesive system for reinforced strapping tape

DETAILED DESCRIPTION OF THE INVENTION The term "hot melt" as used herein refers to a composition that is essentially solventless which is coated at an elevated temperature and cooled to set the coating.
A reinforced strapping tape 10 in accordance with one embodiment of the present invention is illustrated in FIG.
1 and comprises a support 12 having on one surface thereof a release agent 14 and on the opposite side thereof a layer of a laminating adhesive 16.
A layer of reinforcing strands 18 is laid on the surface of the laminating adhesive layer 16 and a thermoplastic composition such as a hot melt pressure sensitive adhesive 20 is applied over the reinforcing layer such that it surrounds and penetrates the spaces among the reinforcing strands 18 and provides a continuous adhesive layer overlying the reinforcing strands 18.
A layer of natural rubber adhesive 22 is coated on top of the hot melt pressure sensitive adhesive 20.
Since only a thin layer of the natural rubber pressure sensitive adhesive 22 is applied, the level of solvent vapor liberated while coating the natural rubber adhesive is drastically reduced allowing the natural rubber adhesive 22 to be applied at speeds higher than can be employed using a natural rubber adhesive alone in the absence of a hot melt pressure sensitive adhesive.
The backing support of the present reinforced strapping tape may be any of the materials commonly used in the industry and typically includes biaxially oriented polypropylene (BOPP), polyethylene terephthalate (PET), machine direction oriented polypropylene (MOPP), paper, polyethylene, and the like.
Preferably, the backing support is polyethylene terephthalate or biaxially oriented polypropylene.
Any conventional release agent can be used to provide the release properties.
Representative examples of the release agents useful in the present invention include polyvinyl octadecyl carbamate (PVODC); a C.
sub.
14 -C.
sub.
18 fatty acid coordinated with a transition metal such as chromium; the reaction product of a di-