Bridge tape

Abstract

Bridge tape comprised of thermally foamable composition, useful for applying coating material through holes in the tape to a substrate beneath the tape, after which the holes can be sealed by heating to cause the foamable composition to foam and expand the foam to seal the holes.

Claims

1. A bridge tape comprising: a first layer comprising a foamable composition; a second layer comprising a backing material; a third layer comprising an adhesive coating; and a plurality of holes passing through the bridge tape, wherein the second layer is disposed between the first layer and the third layer.

2. The bridge tape of claim 1, wherein the bridge tape has been die-cut to form a die-cut patch.

3. The bridge tape of claim 1, wherein the backing material comprises a cloth tape.

4. The bridge tape of claim 3, wherein the adhesive coating comprises a two-sided adhesive tape.

5. The bridge tape of claim 3, further comprising a release liner disposed on the third layer, wherein the third layer is disposed between the second layer and the release liner.

Description

BRIEF DISCUSSION OF THE DRAWINGS

(1) The construction of several embodiments of the bridge tape of the present invention is illustrated in the following figures, in which

(2) FIG. 1 illustrates a side view of a section of the bridge tape of the present invention having the following layers:

(3) Layer 1 is a layer of a foam foamable composition,

(4) Layer 2 is a layer of an adhesion promoter,

(5) Layer 3 is a two-sided tape,

(6) Layer 4 is an adhesive coated fabric liner, and

(7) Layer 5 is a release liner on the adhesive coated fabric liner.

(8) FIG. 2 illustrates an alternative embodiment of the bridge tape of the invention, in which:

(9) Layer 6 is a layer of a foamable composition,

(10) Layer 7 is a layer of backing material, such as an adhesive coated fabric liner, and

(11) Layer 8 is a release liner on the adhesive coated side of the fabric liner.

(12) FIG. 3 illustrates the top view of the bridge tape patch of FIG. 2, after holes (9) have been punched into it,

(13) FIG. 4 illustrates the bridge tape patch of FIG. 3, after it has been subjected to heat treatment to cause the foamable composition to foam and expand the foam to seal the holes, the sealed holes being illustrated in outline (10).

DETAILED DESCRIPTION

(14) As shown in FIG. 1, the bridge tape is formed of a layer of a foamable composition adhered to a backing material, such as a cloth liner having an adhesive coating or layer of a transfer tape, and a release liner over the adhesive coating or transfer tape.

(15) As backing material for the bridge tape of the present invention it is possible to use all known textile backings, such as wovens, knits or nonwoven webs; the term nonwoven web embraces at least textile sheetlike structures as well as stitchbonded nonwovens and similar systems. It is likewise possible to use spacer fabrics, including wovens and knits, with lamination.

(16) A preferred backing material comprises woven cotton fabric, typically having a mesh count in the range of 140 to 160, preferably 148 (implying a warp thread count of 74 and a weft thread count of 74).

(17) With further preference the weft count is 70 to 80 and/or the warp count is 70 to 80.

(18) As adhesives on the backing it is possible in principle to choose a variety of polymer systems, with natural-rubber or synthetic-rubber and also acrylate systems having proven particularly advantageous if their adhesive properties and temperature stabilities are in accordance with the requirements. With further preference the bond strength to steel is at least 5 N/25 mm.

(19) A suitable adhesive is one based on acrylate hotmelt which has a K value of at least 20, in particular more than 30 (measured in each case in 1% strength by weight solution in toluene, 25.degree. C.), obtainable by concentrating a solution of such an adhesive to give a system which can be processed as a hotmelt.

(20) It is also possible to use an adhesive comprised of natural rubbers or synthetic rubbers or of any desired blend of natural rubbers and/or synthetic rubbers, it being possible to select the natural rubber or the natural rubbers in principle from all available grades, such as, for example, crepe, RSS, ADS, TSR or CV grades, depending on the required purity and viscosity level, and to select the synthetic rubber or synthetic rubbers from the group of randomly copolymerized styrene-butadiene rubbers (SBR), butadiene rubbers (BR), synthetic polyisoprenes (IR), butyl rubbers (IIR), halogenated butyl rubbers (XIIR), acrylate rubbers (ACM), ethylene-vinyl acetate (EVA) copolymers and polyurethanes and/or blends thereof.

(21) With further preference it is possible to add thermoplastic elastomers to the rubbers, in order to improve the processing properties, with a weight fraction of from 10% to 50% by weight, based on the total elastomer fraction.

(22) As representatives mention may be made at this point in particular of the especially compatible styrene-isoprene-styrene (SIS) and styrene-butadiene-styrene (SBS) products.

(23) Tackifying resins which can be used include without exception all tackifier resins which are already known and have been described in the literature. As representatives mention may be made of the rosins, their disproportionated, hydrogenated, polymerized, and esterified derivatives and salts, the aliphatic and aromatic hydrocarbon resins, terpene resins and terpene-phenolic resins. Any desired combinations of these and further resins may be used in order to adjust the properties of the resultant adhesive in accordance with requirements. Express reference may be made to the depiction of the state of the art in the Handbook of Pressure Sensitive Adhesive Technology by Donatas Satas (van Nostrand, 1989).

(24) Heat-activatable adhesive sheets may be used for the adhesive layer on the backing layer. Such heat-activatable adhesive sheets preferably have the following composition: i) a polymer, with a fraction of at least 30% by weight, a first section of the heat-activatable adhesive sheet being based with particular preference on reactive polyurethane, polyamide, nitrile rubber with reactive phenolic resins or reactive epoxy resins, and/or a second section being based on thermoplastic, non-reactive polyamides or epoxides, ii) one or more tackifying resins, with a fraction of 5% to 50% by weight, and/or iii) epoxy resins with hardeners, and accelerators, if desired, with a fraction of 5% to 40% by weight.

(25) The adhesive sheets preferably have a thickness of from 10 to 500 m.

(26) The compositions for the adhesive sheet can be widely varied by changing the type and proportion of raw materials. It is also possible to obtain further product properties such as, for example, color, thermal conductivity or electrical conductivity, by means of selective additions of dyes, mineral and/or organic fillers, silicon dioxide for example, and/or powders of carbon and/or of metal.

(27) The foamable layer is preferably formed of a foamable polyurethane composition or of an EVA (ethylene vinyl acetate), with a blowing agent, having a layer thickness prior to expansion of from about 1.5 to about 4 mm and comprising a foaming agent. A particularly preferred expandable foam is that formed of ethylene copolymers and available from ND Industries, Inc. under the product name NB169P041.

(28) These materials are laminated together to form the bridge tape of the present invention. Once formed, the bridge tape is die cut to the size required for the particular use, and, if necessary, holes punched through it.

(29) FIG. 2 illustrates a further embodiment of the bridge tape of the present invention, in which the foamable composition (6) has been extruded directly onto the backing layer (7), such as an adhesive coated fabric with a release liner (8).