Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
1999-05-21
2002-03-12
Zirker, Daniel (Department: 1771)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S354000, C428S3550AC, C428S921000, C442S151000
Reexamination Certificate
active
06355344
ABSTRACT:
INTRODUCTION
The present invention is directed to pressure sensitive adhesive film material suitable for use, for example, as pressure sensitive adhesive tape and the like. In particular, the present invention is directed to pressure sensitive film material which causes substantially less fogging of adjacent surfaces, such as glass surfaces, due to outgassing of materials, such as plasticizers and the like.
BACKGROUND
Pressure sensitive adhesive tapes are well-known for use in diverse applications. Typically, PSA tapes employ a backing film or web, such as a plastic film, to carry a layer of pressure sensitive adhesive. Among the numerous use applications well-known for PSA tapes are electrical tape and harness tape, that is, tape used for securing bundles of wires in wire harness fabrication. Existing PSA tapes have various shortcomings, especially PSA tapes employing a flexible polyvinyl chloride (PVC) backing web. PVC materials are difficult to recycle, due in part to their halogen content, and due in part to poor stability during processing since Hydrochloric acid is a byproduct of the decomposition of this polymer. In addition, PVC films typically employ significant quantities of plasticizers to achieve adequate conformability and other performance characteristics. The plasticizer content of PVC film is problematic in many use applications, due in part to its outgassing over time, especially at elevated temperatures. Not only can such plasticizer outgassing degrade the properties of the PSA tape, this process also can result in fogging of adjacent surfaces. The outgassed plasticizer condenses on adjacent surfaces causing a fog or haze on the surface. Notably, PVC adhesive tapes employed in wiring harnesses used in the passenger compartment of motor vehicles, such as in the dashboard, are a significant cause of windshield fogging.
Notwithstanding these longstanding shortcomings, PSA tapes employing PVC backing films have not easily been replaced. Numerous performance characteristics must be met by any replacement PSA tapes. Particularly for use as harness tape, a PSA tape must demonstrate good use characteristics, such as good conformability, with stress relaxation and dead fold properties, as well as hand tearability. In addition, any such replacement PSA tape must have good long-term heat aging in view of the extended product life for a motor vehicle wire harness, and especially in view of the temperature cycling which occurs within a motor vehicle passenger compartment or, even more so, within a motor vehicle engine compartment. In addition, PSA tape intended for use as harness tape typically is supplied in rolls, and must unwind from the roll without ratcheting and without requiring excessive force since, frequently, they are applied by hand. Further, it is highly desirable that any such alternative to the known PVC tapes should have a laterally-across straight edge tear by hand. That is, a person applying the tape should be able to easily rip the tape from the remaining roll at 90 to the longitudinal direction of the tape with substantially no curl or jaggedness at the newly-formed free end of the tape. Similarly, the force required to cross-rip the tape by hand must not be excessive, yet the tape must exhibit strength adequate to its intended application. Of course, the tape must also have a suitable adhesiveness level. Thus, the backing film or web must be compatible with a suitable adhesive which when combined with the backing web provides the aforesaid performance characteristics. Compatibility of the adhesive and the backing web is required to ensure the integrity of the interfacial bond between the backing web and the adhesive, while avoiding problems such as “blocking” of the adhesive tape roll. Moreover, the backing web and the compatible adhesive desirably would be employed with existing, commercially known manufacturing equipment and techniques for producing PSA tape. Better PVC alternatives are needed for pressure-sensitive adhesive tapes and other PSA film materials, having performance characteristics meeting most or all of these industry criteria. Large end users of PSA tapes and other PSA film materials, such as the motor vehicle industry, have long desired new materials which demonstrate less fogging and yet meet the other stringent performance characteristics required of the particular use application. While innumerable polymer materials are known which might be formed into films or webs for use in adhesive tape applications, efforts to identify a suitable alternative to PVC films for pressure sensitive adhesive materials have encountered difficulties either in the performance of the film material itself, its compatibility with a suitable adhesive, or both.
It is an object of the present invention to provide flexible, conformable, pressure-sensitive adhesive film material which exhibits low or insignificant fogging. It is a particular object of at least certain preferred embodiments of the invention to provide PSA tape and other PSA film material suitable to serve as an alternative to known PVC adhesive tapes in diverse application including, for example, as harness tape for passenger compartment and engine compartment wire harnesses for motor vehicles and similar applications. Additional objects and advantages of the present invention will be more fully understood from the following disclosure and detailed description of the invention.
SUMMARY
Selection and development efforts have now lead to a new class of pressure sensitive adhesive tapes and other flexible, conformable PSA film materials having excellent performance characteristics. The PSA film materials disclosed here do not require PVC backing films and, therefore, can achieve substantially reduced fogging. Various embodiments of the invention are suitable for use as electrical tapes, binding tapes, etc., and numerous use applications will be apparent to those skilled in the art given the benefit of the following disclosure and detailed description. Notably, certain preferred embodiments of the new PSA film materials disclosed here, that is, preferred versions employing certain advantageous combinations of materials, layer thicknesses, etc., are found to provide excellent performance characteristics for use as wire harness wrapping tape, especially as harness tape for motor vehicle passenger compartment and engine compartment applications.
In particular, pressure-sensitive adhesive film material disclosed here, as roll tape or in other forms, are found to have performance characteristics suitable for numerous applications presently served by PSA materials employing polyvinyl chloride backing films. The PSA tapes and other materials disclosed here, in particular, can be formulated to have excellent conformability, with good stress relaxation and dead fold properties, as well as good hand even after extended storage or exposure in a use application. They also have good temperature stability for meeting long-term heat aging requirements. Formulated for harness tape applications, the PSA tapes of the present invention have excellent cross-rip properties, including laterally-across straight edge tear by hand. In that regard, cross-rip forces for such preferred harness tape embodiments can meet specified ranges appropriate for hand application of the tape. Also, the unwind forces of such preferred harness tape embodiments can meet ranges specified for hand application of the tape, with little or no ratcheting or blocking of the tape rolls. These advantageous performance characteristics have been obtained by identifying the compatibility of suitable adhesives with suitable plastic backing films and other required ingredients or components. The PSA film materials of the invention do not require PVC backing films and, hence, can be more readily recycled. Moreover, harness wrap tape in accordance with numerous and preferred embodiments of the invention can be produced using manufacturing equipment and methods which are in current commercial use, thereby providing significant advantage over any other alt
Goldsmith Paul S.
Jerry Serra M.
Mamish Abboud L.
Tyco Adhesives LP
Zirker Daniel
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