WO1997009391A1

WO1997009391A1 - Tape or sheet coated with gel adhesive

Info

Publication number: WO1997009391A1
Application number: PCT/GB1996/002170
Authority: WO
Inventors: Michael John Percy; William Joseph Egenton; Paul Andrew Bradley; Ian Laird; John Michael Hudson; Norman Hutt; Philip James Hammond; Alistair Alfred Preston Sutherland; Patrick James Horner
Original assignee: Raychem Limited
Priority date: 1995-09-07
Filing date: 1996-09-04
Publication date: 1997-03-13
Also published as: AU6834896A

Abstract

Low-cost general purpose sealing product comprising thick gel coating on thin burst-resistant film backing useful as cost-effective bung in refrigerator casing foam injection and many other uses. Hot lamination and specific gel backing thickness ratios are described, the preferred materials being oil-extended styrene-elastomer-styrene triblock copolymer gels on EVA backing. Double-sided gel tape, or unsupported gel tape, preferably of at least 15 % triblock content, wrapped around cable to seal wall feedthrough. Includes different gels on opposite sides of backing; reticulated foam backing filled by gel; closed cell foam backing; gel tape in plane of carrier sheet; unsupported gel profile (of any shape) in automotive headlamps; non-aqueous gels of any form in acid or alkali, especially electrolyte compartments and barriers in batteries and dry cells; gel layers (preferably thermally conductive) in face-to-face contact with printed circuit boards; gel profiles as gland packing materials, e.g. for masts of ships; gel-filled foams as mats e.g. non-slip mats for boats; and gel seals in glazing frames.

Description

TAPE OR SHEET COATED WITH GEL ADHESIVE

This invention relates to gel tapes or sheets, which may be useful in a wide range of sealing applications.

Gel tapes and sheets having porous internal or external supports are described, for example, in EP-A-0108518 (MP0838), EP-A-0194872 (MP1043), EP-A-0204427 (MP1054), EP-A-0203737 (MP1056), and WO-A-9416884 (MP1469). These known products are very successful, but may be unsuitable or not cost-effective in some applications. The tapes or sheets according to the present invention tend to be more versatile and cost-effective than the above known tapes and sheets, especially in certain applications hereinafter described.

A first aspect of the invention accordingly provides a gel tape or sheet comprising a backing of substantially non-porous flexible polymeric film not more than 0.2 millimetres thick adhered to a layer (preferably a self-supporting layer) of thermoplastic gel not less than 0.5 millimetres and not more than 20 millimetres (preferably not more than 15 mm, more preferably not more than 10 mm) thick, wherein the thickness of the gel layer is at least 5 times (preferably at least 10 times, possibly at least 15 or at least 20 times) that of the backing. Preferably the strength of the backing is sufficient to withstand pressure applied thereto by a substantially spherical or semi-spherical resilient body of 2 cm diameter to force a substantially central region of the gel surface of a square of the tape, the square measuring 4 cm along each edge, into contact with as much as possible of the internal surface within 1 cm of one corner of a 5 cm substantially rigid hollow cube. Up to three of the cube walls may be removed to facilitate this test insertion of the square.

The first aspect of the invention thus provides an extremely versatile and useful slab gel tape or sheet, in which the robustness of the thin, flexible backing enables the softness, cohesion and sealing ability of the thick layer of gel to be conveniently and cost-effectively used in a multitude of sealing applications, especially those wherein the slab of gel is required to bridge or fill a depression or aperture and/or to resist pressures encountered after sealing.

The thermoplastic gels are visco-elastic materials of relatively high cohesive strength with elongation to break of at least 500%, preferably at least 750%, more preferably at least 1000%; elastic recovery to at least 100%, preferably at least 200%, elongation; and preferably substantially zero slump at temperatures up to 100 degrees, preferably up to 120 degrees, more preferably up to 135 degrees, and especially up to 150 degrees, Celsius. These gels are thus distinguished from commonly known viscous sealants such as tackified elastomer mastics and pressure-sensitive adhesives. It is an advantage in terms of simplicity that the thermoplastic gel layer may preferably be self- supporting in the sense that it does not require an internal porous support of the kind used with known cross-linked polysiloxane gels, although the use of such a porous layer carrying the thermoplastic gel therewithin is not necessarily excluded.

The substantially non-porous backing may contain micropores which are often present in extruded polymeric films, but will not include the foam cells or high void volumes (eg. 45% void volume) of the known porous supports. Any void volume in the backing for the present gel tape or sheet will therefore be less than 20%, preferably less than 10%, more preferably substantially zero.

A second aspect of the invention provides a gel tape or sheet comprising a backing of polymeric material, preferably thermoplastic polymeric material, melt-coated with an adherent layer of thermoplastic gel of thickness at least 5 times, preferably at leat 10 times, possibly at least 15 or at least 20 times, the thickness of the backing.

It was unexpected that melt-coating of such a relatively large volume slab of gel onto such a relatively thin backing could be achieved without the considerable heat content of the gel distorting or otherwise interfering with the backing, especially thermoplastic backing. Preferably, the backing is thermoplastic and the application temperature of the gel is sufficient to produce surface melting of the backing at the gel/backing interface, but not so high as to melt the backing entirely or to an unacceptably weakening extent. The appropriate relative temperatures will depend on the physical characteritics of the materials and on the equipment and conditions used, but may readily be adjusted by simple trial and error to produce the desired interfacial fusion which tends to produce superior adhesion of the gel to the backing. For example, a layer of a preferred triblock copolymer gel (hereinafter described) may be extruded at a temperature of about 200 degrees Celcius and cooled to a temperature of about 150 degrees Celsius before being contacted with a preferred ethylene/methyl acrylate copolymer backing (hereinafter described) having a DSC melting point of only about 90 degrees Celcius.

Although tapes and sheets wherein the backing is relatively easily removable from the gel are not excluded from the present invention, it is preferred that the backing and gel have been brought into contact with each other under conditions which enhance their mutual adhesion, preferably by interfacial melting as aforesaid. In a preferred embodiment of this aspect of the invention, the backing is thermoplastic and the said contact is at a gel temperature higher than the melting or softening temperature of the backing by not more than 100°C, preferably not more than 80°C, more preferably not more than 60°C.

In many cases, it will be preferred to combine the aforementioned first and second aspects of this invention, and any or all of the other features herein described may be used together with that combination or with either of the said aspects individually.

For many purposes, especially when the thickness of the backing is 0.05 mm or less, the advantages of the slab gel tape or sheet according to the present invention may be enhanced when the thickness of the gel is at least 20, preferably at least 30, more preferably at least 40, times that of the backing. These and the aforementioned ranges of gel thickness relative to the backing have been found particularly convenient for use in hand-applied seals, especially when the tape or sheet is used in handy patches of a size suited to thumb or finger insertion into hollows or apertures to be sealed, for example as hereinafter described. For most practical purposes, it will be convenient if the thickness of the gel is not more than 100, preferably not more than 50, times that of the backing. Convenient slab gel tapes and sheets for many purposes, especially the aforementioned handy patches, are those wherein the backing is 0.05 to 0.15 mm thick and the gel is 1 to 3 mm thick, or possibly for some purposes 4 to 6 mm thick.

It will be appreciated that the ability of the slab gel tape or sheet to withstand thumb or finger installation, as aforementioned, is reflected in the aforementioned preferable test of strength using a 2 cm resilient spherical body. For such applications, although not necessarily for all applications of the present slab gel tape or sheet, it is preferable that the stiffness and/or elastic recovery force of the backing is/are sufficiently low and/or the tack and/or adhesion strength of the gel is/are sufficiently high to resist, or preferably avoid substantially completely, any withdrawal of the gel by the backing from the surface contact specified in the aforesaid test for at least 15, preferably at least 30, minutes after cessation of the application of the said pressure.

It is especially advantageous if the thinness and/or the flexibility or other characteristics of the backing material is/are selected so that the backing has a negligible or substantially zero effect on the continuing adhesion of the gel to any concave surface, especially when the tape or sheet has been placed across the concavity and subsequently pressed into it with resultant curvature and possibly deformation of the backing. Thus, it is preferred that the backing will not to any unacceptable degree (preferably substantially not at all) pull the gel away from the surfaces to which it is applied after removal of the applying pressure.

The adhesion strength of the gel may be inherent in its polymer and/or its extender liquid, or in the combination of the two, or may be adjusted and/or enhanced by addition of tackifiers, for example polyterpene tackifier resins, or other polymers or materials that have a tackifying effect, whether or not they are normally known as tackifiers. The adhesion strength of the gel to the backing is preferably greater than the cohesive strength of the gel and/or greater than the adhesion strength of the gel to a material other than the backing with which the gel will be in adherent contact in use. In effect, this means that a gel will preferably peel adhesively away from the other material, or will fail cohesively, before the backing can be pulled away from the gel in use. The invention however does not exclude cases where the adhesion of the gel to the backing is lower than the gel's cohesive strength, provided that the adhesion of the gel to the backing will always be significantly higher, preferably at least 50% higher, than the adhesion of the gel to known release surfaces such as silicone-coated paper or polytetrafluoroethylene .

In most cases, the backing will be a self-supporting polymeric film. Suitable films may be selected by simple trial and error to suit the adhesion characteristics of the gel in question. For example, films, possibly crosslinked films, of low-density polyethylene, nylons, polyesters, polypropylene/polyethylene blends, or polyethylene copolymers may be useful with some gels in some circumstances, possibly after surface treatments such as corona or chromic acid oxidation to enhance surface adhesion. For the tri-block copolymer gels hereinafter described, it is preferred that the backing comprises at least a weight majority of ethylene/vinyl acetate copolymer or ethylene/methyl acrylate copolymer. Preferred materials include known EVA's such as ELVAX (Trade Mark) 470, and EMA's such as OPTEMA (Trade Mark) TCI 15 from Exxon.

For the slab gel tape or sheet according to the present invention, it is preferred that the gel comprises a thermoplastic triblock copolymer having relatively hard crystalline end blocks and an elastomeric mid-block extended with at least 500, preferably at least 600, more preferably at least 700, parts by weight of an extender liquid which softens and extends the said mid-block per 100 parts by weight of the triblock copolymer, the amount of extender liquid not exceeding 5000 parts by weight per 100 parts of the triblock copolymer. Lower extender contents, for example down to 400 or perhaps even down to 300 parts of extender liquid per 100 parts of the triblock copolymer, may be useable in some circumstances, but the benefits of this invention will usually be better realised with the softer gels containing 500 or more parts of the extender liquid. Preferred triblock copolymer gels for the present purposes are those wherein the triblock copolymer has polystyrene or polyalkylmethacrylate end blocks and has a polyalkylene (hydrogenated or not) mid-block, preferably a poly(ethylene/butylene) and/or poly(ethylene/propylene) mid-block. Other materials, such as tackifying di-block copolymers or other tackifiers may be present as aforesaid, and other additives such as colouring dyes and pigments, flame-retardants, anti-oxidants, and melt-viscosity adjusters may be added in known manner. The triblock gels will preferably have the characteristics and meet the criteria described in any or all of WO-A-8800603 (EP-A- 0426658) (RK308), WO-A-9305113 (RK451), WO-A-9323472 (RK469), and WO-A- 9418273 (RK472), the disclosures of all of which are incoφorated herein by reference. Those disclosures deal mainly or wholly with triblocks having polystyrene end blocks. For higher temperature performance, it may be preferable to use the new triblock gels having polyalkylmethacrylate end blocks described in our co-pending International Patent Application PCT/GB96/01381 (RK509). The triblock copolymer gels have been found especially cost-effective and useful for the slab gel tapes or sheets of the present invention.

The slab gel tapes or sheets may be provided in various forms for convenient practical use. For example, the tape or sheet may be provided having a removable release-coated sheet or tape in contact with the surface of the gel remote from the backing. In one especially convenient form, the release sheet or tape may carry a plurality of separately-removable sections of the slab gel tape or sheet, for example for sequential removal and installation in items on a production line. An especially convenient form of the slab gel tape or sheet may be substantially square or rectangular with the length of its sides or its smaller sides being 2 to 4 cm. Thus, the slab gel tape or sheet may be a long, relatively- narrow tape, whose width is the smaller side referred to; or may be a much shorter rectangle or square, for example the handy patches hereinbefore mentioned.

In another variation, the slab gel tape or sheet may have at least one slit or aperture for positioning around an object which is to project through the tape or sheet in use. This form of the invention may be especially useful for sealing around cables or pipes or other elongate objects, for example where they pass through an aperture in a wall. This form of the invention may be a handy patch having one or more apertures or a larger sheet or longer tape having a series of the apertures, which sheet or tape can be for cut to provide smaller portions such as the handy patches each having at least one of the apertures or slits.

A convenient preferred form of the slab gel tape or sheet may be marked for separation into smaller portions. With or without such convenient markings, the slab gel tape or sheet may be provided in a dispenser for dispensing and cutting off selected portions of the tape or sheet. Suitable dispensers will readily be devised, and may resemble those used for dispensing pressure-sensitive adhesive tapes.

The slab gel tapes or sheets according to the present invention have a wide variety of uses, usually involving environmental sealing, although other applications, for example electrical insulating, acoustic insulation, corrosion protection, or vibration damping, are not excluded. Owing to the cohesive strength of the gels, the slab gel tape or sheet is especially useful in circumstances where re-opening of the seal may be desired from time to time.

A third aspect of this invention relates to an especially interesting application of the slab gel tapes or sheets is their use as a block or bung in apertures of the thermally- insulating casings of domestic appliances such as refrigerators, the gel bung serving to retain in the casing the foaming polymer which is injected into the hollow casing walls to produce foam thermal insulation during manufacture of such appliances. The refrigerator casing is assembled from side walls and lid formed of enamelled metal sheet, with a back wall sometimes made of fibrous board with a metallised water-proofing laminate. Inside this casing fits the moulded plastics inner wall of the refrigerator, leaving space between the casing and the inner wall for the thermal insulation. Before the foaming polymer insulation material is introduced into the cavity, all gaps between the casing component walls must be securely sealed to prevent the foaming polymer from exuding to contaminate the outer surface of the casing, with resultant loss of production time and products. Known techniques for this sealing of the casing gaps can be unreliable, especially at the three-edged corners of the casing where two walls and the lid meet. A putty-like substance currently pushed in by hand to fill these three-edged corners tends to come away from the sealing surfaces owing to flexing of the casing walls during movement of the casing to the next stage of production. The resulting leaks and loss of production can seriously reduce the cost-effectiveness of high- volume production lines, and operators may tend to use excessive amounts of the sealant, which may interfere with or even damage the casing assembly. The slab gel tape or sheet of the present invention is uniquely able to address these problems.

This third aspect of the present invention accordingly provides a method of sealing an aperture in a three-dimensionally concave (usually three-edged) corner of a hollow body, comprising pressing into the said corner a patch of a slab gel tape or sheet according to the present invention thus causing the gel to adhere the patch to the internal surfaces of the hollow body so as to seal off the said aperture from flowable material to be introduced subsequently into the hollow body. The relatively high elongation and cohesive strength of the gels and the relatively thick layer of gel on the slab gel tape or sheet of this invention tends to enable the patch to seal these difficult corners despite wrinkling which is likely to occur on pressing an initially substantially flat patch into such a corner, and despite subsequent flexing of the walls of the hollow body, which may occur in refrigerator casings as aforesaid. The relatively thin backing, being substantially non-resilient or "dead" as aforementioned, tends to enable the patch to stay in place while awaiting introduction of the flowable material, for example the foaming polymer insulation into the refrigerator casing. The patch can therefore advantageously be of substantially uniform thickness, and can thus advantageously control the amount of material used for each seal to improve the quality and uniformity of result compared, for example, with the aforementioned variable amounts of the known putty-like sealantfor refrigerator casings. Preferably the backing is substantially permanently adhered to the slab of gel, it being desirable to avoid separation of the backing from the gel at least for such time as may be required for the flowable material to be introduced. The gel at ambient temperatures is preferably inherently pressure-adhereable to the internal surfaces of the hollow body, so that the patch can be applied thereto at ambient temperatures, preferably by hand, although machine-assisted installation is not excluded. Preferably, the gel is pigmented to substantially match the exterior colour of the hollow body, this being advantageous if the gel should be or become visible to any extent from the outside of a refrigerator casing or other hollow body. For white goods such as refrigerators or freezers, white pigmentation, for example by incoφorating 2% by weight of titanium dioxide into the gel, would be preferred.

A fourth aspect of the present invention includes the slab gel tapes or sheets when arranged to seal a depression or aperture with the gel bridging and adhering to all edges thereof. This will be the case, for example, when a handy patch of the gel tape or sheet is placed across the depression or aperture and then pressed into it as hereinbefore described.

A fifth aspect of the invention also includes the tape or sheet when wrapped around an object extending through an aperture so that one or more layers of the tape or sheet fill the space between the object and the inner circumference of the aperture. For example, the tape or sheet may be wrapped around upon itself sufficient times to fill the space between a cable and a through-hole in a wall or bulkhead through which the cable extends. In such cases, the gel may face inwards, the innermost layer of gel thus adhering to the object, or may face outwards, so that the outermost layer of gel adheres to the inner surface of the aperture. In either case, further sealant or adhesive may be provided to cause the backing to adhere to the object or the aperture surface as appropriate.

A sixth aspect of the invention further includes a method of making a slab gel tape or sheet according to this invention, the method comprising melt-extruding a tape or sheet of the gel and bringing it (preferably continuously) into contact with a tape or sheet of the backing. Suitable equipment for extruding the gel and feeding it into contact with the (preferably continuously fed) backing may be selected according to convenience from conventional extruders or commercially available equipment used to dispense hot-melt adhesives, for example gear-pump-driven hopper melters and/or drum unloaders available under the Trade Marks Nordson or Meltex. Suitable equipment for performing this method and adjusting the conditions as hereinbefore mentioned may readily be devised, for example including a suitable distance between the gel extrusion head and the backing contact point and/or for example including cooled rolls in contact with the backing or the gel at and/or after the contact point. As an alternative to feeding the pre¬ formed backing from a roll, the backing may be continuously extruded and fed from the extruder into contact with the separately extruded gel. A further possibility is to co¬ extrude the backing and gel together from suitable co-extrusion equipment. In all cases, the cooling of the tape or sheet formed from the extruded gel and/or backing may be effected or assisted by means of fans or by feeding the product through a water bath, which has been found to consolidate the preferred materials suφrisingly well.

The backing may be coated with the gel in any width and subsequently cut to size, for example by slitting and rolling up to provide rolls of tape in widths such as the preferred 4 cm width, or by cutting up into sheets of convenient size. The tape or sheet may be provided with a release covering, for example silicone-coated paper, if desired. It is also possible to stamp out of the tape or sheet gaskets or other articles of any desired shape or size.

Specific examples of the present invention will now be described by way of further illustration, with reference to the accompanying drawings, wherein: -

Figure 1 shows schematically the tape production method of following Example 1;

Figure 2 illustrates schematically the method used in Example 2; and

Figures 3 to 5 illustrate schematically the use of the slab gel tape in the aforementioned sealing of refrigerator cabinets.

Example I

Ethylene/methylacrylate copolymer tape (OPTEMA TCI 15) of about 30cm width was fed from a reel (10, Fig.l) thereof. A gel (14, Fig.l) comprising 8% by weight SEPTON 4055 styrene-ethylene/butylene+ethylene/propylene-styrene triblock copolymer, 8% by weight SEPTON 1001 styrene-ethylene/propylene copolymer, and the remainder of the substantially non-aromatic extender oil described in the aforementioned triblock copolymer disclosures, the gel being prepared along the lines described in the aforementioned WO-A-9323472, was extruded from extruder 16 at a diehead temperamre of 200 degrees Celsius onto a silicone-coated fabric belt conveyor 12, which acted as a cooling heat sink, and the backing was fed from the roll 10 into contact with the exposed surface of the gel on the conveyor. The surface temperature of the gel on contact with the backing was approximately 145 degrees Celsius. Extrusion was continued at a rate of about 2 metres per minute.

Example 2

In this example, ELVAX 470 (Trade Mark) EVA copolymer tape (20, Fig.2) of about 0.5mm thickness was melt-formed directly from an extruder 22 at about 180-200 degrees Celsius and was fed across a cooling interval of about 5 cm into contact with a conveyor 25 where it received a coating of gel 24 extruded from a MELTEX (Trade Mark) pump 26 at about 200 degrees Celsius. The gel in this example comprised 11.5% SEPTON 2006 triblock copolymer and 5.5% SEPTON 1001 diblock copolymer with the aforementioned extender oil.

Figure 3 shows schematically a refrigerator cabinet partly cut away to show in cross-section the foamed polymer insulation 30 between the moulded plastics inner shell 32 and the outer casing formed by enamelled metal side walls 34, lid 36, and fibre-board back wall 37. The usual motor M and door D are indicated in greatly simplified form in the interests of clarity. The two-dimensionally-concave or single-edged interior corners between the straight edges 38 of the lid 36 and the underlying edges of the walls 34, 37 may be sealed with the slab gel tape according to the invention or with more conventional masking tapes, since wrinkling of the latter will not tend to be a problem in these relatively straight lines. At the three-dimensionally-concave corners 39 where two walls and the lid meet, the aforementioned advantages of the slab gel tape according to this invention will tend to be most evident. Figure 4 shows schematically two of these comers 39 from inside the casing without the plastics inner shell and insulating foam. In order to seal the gaps between the lid and walls at these comers, it is necessary for the gel to make and maintain sealing contact with areas x, y, and z of the inner surface of the side walls 34, back wall 37, and lid 36 respectively. For puφoses of illustration, masking tape 40 is indicated sealing the straight single-edged corner running from one of the three-edged comers 39 to the floor of the casing.

The seals at x, y, and z are preferably made using a patch of the slab gel tape as shown in Figure 5, the thin backing 50 carrying the much thicker slab coating of gel 52 as hereinbefore described. The illustrated patch is roughly square abd broken lines in Figure 5 indicate the length of slab gel tape from which the patch may have been cut. The patch is simply pushed into the comers 39 with the gel slab facing into the comer.

The aforementioned fifth aspect of this invention relates to a method of sealing the space between the inward-facing surface of an aperture in a barrier wall or bulkhead and an object extending through the aperture, wherein a gel tape or sheet comprising a thin polymeric sheet backing carrying a layer (preferably melt-coated) of gel sealant of thickness at least 5 times that of the backing is wrapped around the object extending through the apermre so that one or more layers of the tape or sheet fill the space between the object and the inner circumference of the aperture, with the gel sealant facing either inwards or outwards to adhere respectively to either the object or the aperture surface. In either case, further sealant or adhesive may be provided to cause the backing to adhere correspondingly to the aperture surface or the object. Such tapes or sheets having a pressure-sensitive or other adhesive on the backing may be advantageous generally for location, assisted by the adhesive, on surfaces of objects which are to carry (e.g. to be sealed by) the sealant (e.g. gel) in service.

As a seventh aspect of the present invention, such a tape or sheet carrying the said gel sealant on both main surfaces of the said backing according to the aforementioned co- pending application is also specifically claimed. It may also be convenient, in these "double-sided" forms, for the continuous film backing to be replaced with a foraminated or net-like reinforcing sheet, which will reinforce the gel and may advantageously be selected and arranged to limit the extent of stretching which occurs when the gel tape or sheet is placed under tension. The said foraminated reinforcing sheet will preferably not be a foamed polmeric material, since the relatively tortuous foramina of a polymeric foam, even when reticulated, may tend to be difficult to fill with the preferred gels by the preferred melt-coating methods, owing to the relatively high melt viscosities of the preferred gels. It will usually be preferable for the said reinforcing sheet to have relatively straight-through foramina, for example as in an open-weave fabric or a perforated sheet or a net, to facilitate melt application of the gel. The gel sealant may be applied to the reinforcing sheet by methods similar to those described in the aforementioned co-pending application, or by any other convenient method.

For the aforementioned wrapped aperture seals, it has been further discovered according to an eighth aspect of the present invention that an unsupported sheet or tape or other elongate article of gel, of whatever cross-sectional profile, may be used without any permanent backing or intemal support. Naturally, the gel will be selected to have sufficient coherent and tensile strength to enable it to be satisfactorily wrapped around the object in question. The gel may be a thermoplastic oil-extended triblock copolymer gel similar to those generally described in WO-A-8800603 (RK308), WO-A-9305113 (RK451), WO-A-9323472 (RK469), or WO-A-9418273 (RK472), the disclosures of all of which are incoφorated herein by reference, based on styrene-hydrogenated alkylene- styrene triblock copolymers (hereinafter "triblocks"). In that case, it is preferred that the gel will comprise at least 15% more preferably at least 20% by weight of the triblock, and preferably not more than 35%, more preferably not more than 30%, possibly not more than 25% , by weight of the triblock, based on the weight of the whole gel composition. The balance of the gel composition may be substantially entirely the extender oil (which term includes suitable extender fluids of all kinds, not merely those conventionally described as "oils"), possibly including minor amounts (for example less than 10%, preferably less than 5%) of additives such as colouring dyes or pigments, antioxidants, or melt-viscosity- adjusters; or the balance of the gel may include significant amounts of other known additives such as tackifying diblock copolymers. Thus, the gel will preferably contain a proportion of the extender oil within the range from 85% to 65%, more preferably 80% to 70%, especially 80% to 75%, by weight, based on the whole gel composition as before. It has been found that some softer triblock gels having less than 15% (e.g. 12%) by weight of the triblock tend to have inadequate strength and/or self supporting ability and/or resistance to tensile elongation for convenient wrapping in the present context.

The unsupported thermoplastic gel articles according to this eighth aspect of the invention are preferably foimed by melt extmsion techniques, suitable conditions for which will be readily determined by persons skilled in such processes, followed by cooling, preferably air cooling on a suitable conveyor belt, to solidify the extmded articles, which can thereafter be rolled up or otherwise packaged for convenient handling. The cross-sectional shape of these articles is not critical and they may be useful in the form of tapes, sheets, or other profiled shapes, e.g. round, oval, triangular, rectangular, or irregular, with or without re-entrant formations.

It has also been found, as a ninth aspect of the present invention, that unsupported elongate gel articles, in the form of such tapes or sheets or other profiled (preferably extmded) forms, having the preferred triblock contents, can be unwrapped from a roll of the elongate gel article in which adjacent layers of the gel are in direct contact with one another, whereas softer or weaker gels would tend to break or elongate to an inconvenient extent on unwrapping. The coherent and tensile strengths of the gel will be adjusted accordingly, for example by selection of the triblock type and molecular weight and/or by selection of the triblock content of the gel, to overcome the adhesion forces between the adjacent layers in the roll. If preferred, the elongate gel article may have a removable release sheet wound between the adjacent layers. The elongate gel articles will preferably be capable of self support (not unduly sagging or breaking) when suspended for 30 seconds at room temperature in horizontal lengths of at least 10cm, preferably at least 30cm, more preferably at least 50cm. Such unsupported gel articles may be usefully applied, from the aforesaid rolls or otherwise (eg. strips carried on a suitable release sheet), for general sealing puφoses, for example sealing of equipment housings where they are joined together or abut against a wall or other surface. Such uses of the unsupported gel tapes or sheets may resemble those described for gel profiles with hollow or solid carriers in WO-A-9609483 (RK508) and WO-A-9618836 (B288), the disclosures of which are incoφorated herein by reference.

When the unsupported gel articles (preferably tapes or sheets) are used for the aforementioned aperture-sealing puφoses, for example in relatively thin walls or bulkheads in vehicles or appliances, or in thicker naval bulkheads or walls in buildings, the gel may be caused to seal the space between the aperture and the object by simple force-fitting of the wrapped gel into the aperture and/or by folding a portion of one or more layers of the wrapped gel protmding from the aperture outwards from the object into contact with an extemal surface of the bulkhead or other wall-like stmcture containing the aperture. It is an advantage of the robust tensile and cohesive strength of the preferred unsupported gel sealants that they can survive such folding back and the resulting separation of adjacent gel layers after the initial wrapping around the object.

Specific embodiments of the seventh and eighth aspects of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: Figure 6 shows schematically in cross-section a cable passing through an aperture in a bulkhead sealed by the method hereinbefore described; and

Figure 7 shows in schematic perspective view the aforementioned "double-sided" tape of sheet having a foraminated or net-like reinforcing sheet.

Referring to Figure 6, a jacketed cable 10 is shown passing through an aperture in a wall 20. Four layers of gel tape 30 have been wrapped around the cable and subsequently the cable has been moved to the left (as illustrated) to bring the gel wrappings into the illustrated position within the aperture. Portions of the gel wrappings project from both ends of the aper re, those on the left side 32 being shown tapered to indicate schematically the possible effect of force-fitting the gel layers into the aperture in wall 20. Two layers of the gel portions 34 projecting from the right hand end of the aperture are shown folded back into contact with the surface of the wall 20 surrounding the aperture.

Optional compression caps 40, 42 are indicated schematically for sliding along the cable 10 and fixing to hold the gel under compression, in this example by bolting the caps 40, 42 to the wall. However, other fixing methods could be used, including securing the caps to the cable, e.g. by means of adhesive, tape wrapping, heat-shrinkable sleeving, or mechanical grips. The caps will preferably be of the hinged or half-shell type assemblable around the cable, but monolithic designs which must be slid over the cable ends are not excluded. The illustrated caps have spaces 41, 43 to accommodate distortion of the protmding gel on compression thereof. The cap 40 will additionally compress the folded-back gel layers 34 against the wall 20. The caps could be replaced by other forms of compression member, for example simple wrappings of pressure- sensitive adhesive tape over and around the protmding gel.

The gel used in this example comprises 24% by weight of Septon 2006 (Trade Mark) styrene-ethylene/propylene-styrene triblock copolymer, extended with Fina A360B (Trade Mark) oil and containing 2% by weight of known antioxidant, as generally described in the aforementioned WO-A-9323472 and other references.

Referring to Figure 7, the foraminated reinforcing sheet 50 is enclosed on both its main surfaces by the gel 52 extmded or coated onto the sheet 50. In practice, the gel will appear as a substantially continuous body extending from on surface of the reinforcing sheet to the other. It may be applied by any convenient method, for example as two separate coatings which adhere to each other through the foramina of the sheet, or as a single all-enveloping coating, or by simultaneous extmsion onto both surfaces of the longitudinally-fed reinforcing sheet. The object to be wrapped in the gel tape or sheet (or other form of unsupported gel article) may be of any form, notably electrical cables or fluid-conveying pipes. This aspect of the invention may find particular utility in sealing around the refrigerator-door- seal-heating return loop of pipe (which conveys heating fluid from the refrigerator compressor to the door seal and back to the compressor) where it passes through the fibre board (metallised cardboard) rear layer of the refrigerator casing on entering and leaving the space between the outer casing and the moulded shell of the refrigerator interior. The necessary pipe-access aperture in the three-edged corner of that cardboard layer, surrounding the space at the rear of the refrigerator which houses the compressor, is especially difficult to seal around the heating pipes in any other way, and reliable sealing is important to prevent loss of production due to escape of the subsequently- injected foam filling compound from the hollow refrigerator body into the compressor compartment.

It will be appreciated that the ranges and ratios of gel thickness to backing thickness hereinbefore specified for the tapes or sheets for sealing refrigerator casings need not be followed when the tapes or sheets are to be used for other puφoses. Therefore, any of the tapes or sheets having a backing as hereinbefore or hereinafter described may, according to end use requirements, use backings of greater than 0.2 mm thickness and/or gel layers less than 0.5 mm thick or more than 20 mm thick, or may use gel layers of thickness less than 5 times the thickness of the backing. Of course the previously-specified ranges and ratios may still be used as appropriate for any puφose, and are preferred for the refrigerator casings and possibly for other aperture-sealing uses.

A tenth aspect of the present invention provides a tape or sheet according to the aforementioned 7th aspect, or having gel and/or backing thicknesses different therefrom, wherein the gel sealant carried on one main surface of the said backing is different from the gel sealant carried on the other main surface of the said backing. The respective gels may differ in any respect which is relevant for the intended end use of the tape or sheet. For example, (a) the gels could have the same components in different ratios, perhaps providing a softer (e.g. more highly oil-extended) gel on one surface and a firmer gel on the other surface; and/or (b) the gels might contain different pigments or fillers, or only one gel might contain a filler or pigment, perhaps to impart different colours to the respective gels, or to render one gel electrically conductive and the other non-conductive, or to render one gel more thermally conductive than the other; and/or (c) the gels may be fonned from different polymers and/or different extender oils, perhaps providing a silicone gel on one surface and a non-silicone gel on the other surface, or providing a thermoplastic (eg. oil-extended triblock copolymer) gel on one surface and a cross-linked (eg. polyurethane or EPDM) gel on the other surface; and/or (d) the gel on one surface may be flame-retarded or U.V. -protected using additives known for such puφoses and the gel on the other surface may have less or none of such additives, or different additives having such effects.

An eleventh aspect of the present invention provides a tape or sheet according to the aforementioned 7th aspect, or having gel and/or backing thicknesses different therefrom, wherein the foraminated reinforcing sheet is formed or reticulated polymeric foam, preferably of average pore size within the range from 3.9 to 11.8 pores per centimetre (10 to 30 pores per inch), more preferably 5.9 to 9.8 pores per cm (15 to 25 pores per inch), especially 7.9 ⁺/- 0.8 pores per cm (20 ⁺/- 2 pores per inch). Usually, the gel sealant will at least partly, preferably substantially completely, fill the spaces within the reticulated foam reinforcement. For some puφoses, it may be prefened that the gel sealant extends beyond one or both main surfaces of the foam sheet at rest (not under compression). For other puφoses, it may be preferred that the gel sealant does not extend beyond one or both main surfaces of the foam reinforcing sheet or tape at rest, in which case it may be desirable that the gel exude from the surface(s) when the article is compressed.

A twelfth aspect of the invention includes the use of a foraminated tape or sheet, preferably of flexible foamed polymeric material (for example the aforementioned reticulated foam), at least partly filled with gel, as a mat, for example an impact- cushioning mat, or a non-slip mat for use on boat decks or elsewhere. The flexibility and surface conformability of the gel facilitates re-positioning of the mat and retention in place once it has been positioned, and the foraminated reinforcement resists undesired degrees of shear deformation of the mat in use. The materials and relative hardness or softness of the gel will be selected from known gels and known characteristics to suit specific end use needs. Because of the supporting effect of the foraminated (preferably reticulated foam) reinforcement, softer gels can be used in this aspect of the invention. For example it may be desirable that the gel sealant comprises a known oil-extended thermoplastic elastomer triblock copolymer gel (hereinafter "triblock copolymer gel") in which the copolymer has relatively hard end blocks and an elastomeric mid-block extended with at least 900, preferably at least 1300, more preferably at least 1800, parts by weight of an extender liquid which extends and softens the said mid-block per 100 parts by weight of the triblock copolymer, the amount of extender liquid not exceeding 10000, preferably not exceeding 7500, more preferably not exceeding 5000, parts by weight per 100 parts by weight of the triblock copolymer. The gel may be applied by solvent casting into the foam sheet, or preferably by melt extmding it onto one or both surfaces of the foam sheet.

It will be understood that the term "gel sealant" is used to refer to the gel materials regardless of whether or not they actually perform a sealing function in any specific article or end use. The gel sealants arguably do not "seal" the mats just described against the surfaces on which they may be used, and may not "seal" the foam support, especially when the gel does not completely fill it. Nevertheless, the term "gel sealant" will be clearly understood by those familiar with gel technology as indicating the kinds of materials required for all aspects of the present invention, almost invariably prefening non-aqueous gels, of which several kinds are now known, although gelatine and similar materials could possibly be used if appropriate for some end uses.

In a 13th aspect of the present invention, there is provided a tape or sheet according to any preceding aspect of the present invention, or having gel and/or backing thicknesses different therefrom, wherein the said backing is a polymeric (preferably closed cell) foam and the gel sealant adheres to its surface substantially without penetrating it. Suitable foams and gels capable of adhering thereto may readily be selected from known materials, and the selection confirmed by simple trial and error. The gels are preferably melt extmded onto the foam, whether by feeding the foam through a suitable extmsion cross head, or by extmding the gel onto the separately-fed foam as it passes by the gel extmsion head. When both surfaces of the foam carry the gel, different gels may be applied to the respective surfaces in a manner analogous to that hereinbefore described for the first aspect of the present invention.

A 14th aspect of the present invention provides a tape or sheet comprising an elongate body of gel attached substantially only to a lateral edge of a canier strip or sheet extending alongside the said body of gel. Canier strip materials will readily be selected from those to which the gel will have sufficiently strong adhesion to maintain the edge attachment under the desired storage and/or end use conditions. A single canier strip may be desirable for some puφoses, but in other cases it may be preferable that the said body of gel is attached substantially only to opposed lateral ledges of two such carrier strips or sheets, preferably extending on substantially opposite sides of the body of gel. In many such arrangements it will be preferable that the two canier strips or sheets be in substantially the same plane as each other. Although the gel may be of a thickness and/or shape such that it projects beyond the plane of the canier sheet(s) surfaces, an especially useful anangement may be one in which the said body of gel is of tape-like, or sheet-like form and lies in substantially the same plane as the canier strip(s) or sheet(s), thus forming a sheet-like article having a stripe of gel between two supporting edge strips. The gel body in all forms of this 14th aspect of the invention may have its own backing or internal re-enforcement, and may be in any of the forms hereinbefore or hereinafter described, preferably an unsupported gel article according to the aforementioned 8th or 9th aspects of the invention.

A 15th aspect of the present invention provides use of an unsupported elongate gel article of appropriate cross-sectional profile, preferably an article according to the aforementioned 8th or 9th aspects of the invention, in a housing component for electrical or other apparams, preferably a headlamp housing component, the gel article being positioned in the housing component so as to be capable of making a seal between the housing component and another body with which the housing component will be assembled in use. This 15th aspect using unsupported gel profiles generally corresponds to the sealing of housings, including headlamps, with supported gel profiles described in WO-A-9609483 (RK508- see especially Figures 8 and 9), the disclosure of which is incoφorated herein by reference. It may altematively be desirable in some circumstances that the said gel article is formed in situ in or on the housing component by melt application of a gel-forming composition thereto.

A 16th aspect of the present invention provides use of a non-aqueous gel, preferably a substantially hydrophobic gel, more preferably an oil-extended triblock copolymer gel, in an aqueous acid or alkali environment, preferably in an electrical battery or dry cell. Non-aqueous, preferably hydrophobic, gels, for example known polysiloxane or polyurethane gels, and especially the oil-extended triblock copolymer gels of the kinds described in WO-A-8800603 (RK308), WO-A-9005166 (RK403), WO- A-9305113 (RK451), WO-A-9323472 (RK469), may be advantageously used for sealing the battery or cell electrolyte compartments or barriers, or for other puφoses, for example protecting conodable components, in the aforementioned acid or alkaline environments. The gels may be either in the form of sheets or tapes, or in other elongate forms, or in bulkier bodies or masses, as necessary to suit particular applications, provided that the polymers and extender "oils" or other materials present in the gels do not unacceptably interact with materials present in the said environments. The gels are preferably held under compression so that their unique cohesive and sealing properties advantageously maintain the seals against slight movements and/or conosion of the sealed surfaces which may occur in use of the batteries or cells. It is also prefened that the surface appearance of the gelsbe as smooth and glossy as possible, since this has been found to enhance the sealing action in battery electrodes and separators and to increase resistance to undermining of the gel sealing interface by chemical or electrolytic corrosion of the sealed components. A 17th aspect of the present invention provides use of a sheet or tape or layer of oil-extended triblock copolymer gel in face-to-face contact with a printed circuit board, the gel being capable of conducting away heat generated in use in components of the circuit board with which the gel is in contact. The gel will preferably contain fillers, for example aluminium oxide or boron nitride, in quantities which increase its thermal conductivity by at least 20%, preferably at least 35%, more preferably at least 50%, over that of the unfilled gel of comparable stiffness (dynamic storage modulus). The excellent interfacial contact achievable at economic cost by means of the gels may provide heat dissipation which is superior to, or more cost-effective than, that achievable with other heat-sink-bonding materials.

An 18th aspect of the present invention provides use of a (preferably elongate) body of gel, preferably oil-extended triblock copolymer gel, as packing in a sealing gland surrounding a member, preferably the mast of a boat, which in use is substantially stationary relative to the gland. The gel body in this aspect of the invention may replace some or all of known gland-packing materials, whether of elongate rope-like form or other forms, and enhanced sealing may be cost-effectively achieved. Gel bodies having the elongate profile or other forms described hereinbefore or hereinafter may for example be useful for this puφose. The glands will preferably not be used where the gels would be subjected to high frictional or shear forces or heat such as might occur in glands for rotating drive shafts.

In all aspects of the present invention, the gels may include additives such as cross¬ linking agents. Fillers and additives may also be used, for example as aforesaid to increase the electrical and/or thermal conductivity of the gels. Flame retardants, pigments, dyes, and other additives may also be used in the usual quantities as desired, if compatible with the desired end-use properties of the gels. The gel surface may be selectively cross-linked, preferably using known cross-linking additives and/or initiators, to form a skin on desired parts of the gel bodies either to reduce surface adhesion, or to enhance the strength and/or handleability of the gel bodies, or both. Gel seals, which may be of any form or any gel material, but preferably comprise gel tapes or sheets or other articles refened to hereinbefore, may provide unique advantages as a 19th aspect of the present invention when used in frame or support structures for windows or glazed doors, especially double-glazed structures and/or structures having multi-component frames.

This 19th aspect of the invention accordingly provides a frame or support stmcmre for a window or a glazed door having at least one gel seal (a) between abutting components of the said stmcmre or (b) between a component of the said stmcmre and (i) adjacent glazing of a window or door or (ii) an adjacent surface of a building in which the said stmcmre is incoφorated.

References to frame or support structures are intended to include (without limitation thereto) structures such as posts, sills, or surrounds which may not be in direct contact with the glass of the door or window, but which define or help to define the door or window aperture in a building and/or which secure or help to secure the door or window in such an aperture. The "glazing" may comprise glass or plastics or other materials known for such pmposes.

The gel materials used may be formulated to resist the degradative effects of sunlight, to which doors and windows are often subjected, for example when the gel is used to seal the window glazing into its frame. Alternatively, or in addition, the gel seals may be positioned, especially for long-term use, so that the gel will be substantially shielded from exposure to sunlight, at least when the said stmcture is incoφorated in a building. The gel seal may, for example, be completely concealed within the frame or support stmcmre into which it is incoφorated during assembly of the stmcmre in a factory or on the constmction site, or it may be placed on a surface of the stmcmre which will abut against a wall or other surface of the building when the stmcmre is installed therein, thus at least partly concealing the gel between the said stmcmre and the building surface. The preferred gel articles hereinbefore mentioned may be especially convenient for application to the frame or support stmcmre before it is installed in the building, since their strength and adherent properties may be selected to ensure that the gel continues to adhere to the stmcmre during storage and/or during installation, which may involve hoisting the stmcture up to building apertures elevated far above a ground-level assembly area.

For reasons of cost-effectiveness, prefened gel seals may comprise a thermoplastic gel, preferably an oil-extended hard block-elastomeric block-hard block triblock copolymer gel, more preferably one in which the hard end blocks comprise polystyrene or polyalkylmethacrylate and/or the elastomeric mid-block comprises hydrogenated or unhydrogenated polyalkylene, preferably polyethylene/butylene and/or polyethylene propylene, for example any of those hereinbefore described.

Claims

CLAIMS ;

1. A gel tape or sheet comprising a backing of substantially non-porous flexible polymeric film not more than 0.2 millimetres thick adhered to a layer of thermoplastic gel not less than 0.5 millimetres and not more than 20 millimetres thick, wherein the thickness of the gel layer is at least 5 times that of the backing.

2. A tape or sheet according to claim 1, wherein the strength of the backing is sufficient to withstand pressure applied thereto by a substantially spherical or semi- spherical resilient body of 2 cm diameter to force a substantially central region of the gel surface of a square of the tapeor sheet, the square measuring 4 cm along each edge, into contact with as much as possible of the internal surface within 1 cm of one comer of a 5 cm substantially rigid hollow cube.

3. A gel tape or sheet comprising a backing of polymeric material, melt-coated with an adherent layer of thermoplastic gel of thickness at least 5 times the thickness of the backing.

4. A tape or sheet according to claim 3, wherein the backing is thermoplastic and the melting temperamre of the gel is not more than 100°C, preferably not more than 80°C, more preferably not more than 60°C, above the melting temperamre of the backing.

5. A tape or sheet according to claim 3 and/or claim 4 and according to claim 1 and/or claim 2.

6. A tape or sheet according to any of the preceding claims, wherein the thickness of the gel is at least 10, or at least 15, or at least 20, times that of the backing.

7. A tape or sheet according to any preceding claim, wherein the thickness of the gel is not more than 100, preferably not more than 50, times that of the backing.

8. A sheet or tape according to any preceding claim, wherein the backing is 0.05 to 0.15 mm thick and the gel is 1 to 3 mm thick or 4 to 6 mm thick.

9. A tape or sheet according to any preceding claim, wherein the backing and gel have been brought into contact with each other at a gel temperamre above room temperamre which enhances their mutual adhesion compared with contact at room temperamre.

10. A tape or sheet according claim 9, wherein the backing is thermoplastic and the said contact was at a gel temperamre sufficient to produce surface melting but not complete melting of the backing.

11. A tape or sheet according to any preceding claim, wherein the stiffness and/or elastic recovery force of the backing and/or the tack and/or adhesion strength of the gel is/are sufficiently low to avoid substantially completely any withdrawal of the gel by the backing from the surface contact specified in claim 2 for at least 15, preferably at least 30, minutes after cessation of the application of the said pressure.

12. A tape or sheet according to any preceding claim, wherein the adhesion strength of the gel to the backing is greater than the cohesive strength of the gel and/or greater than the adhesion strength of the gel to a material other than the backing with which the gel will be in adherent contact in use.

13. A tape of sheet according to any preceding claim wherein the backing is a self- supporting polymeric film.

14. A tape or sheet according to any preceding claim, wherein the backing comprises at least a weight majority of ethylene/vinyl acetate copolymer or ethylene/methylacrylate copolymer.

15. A tape or sheet according to any preceding claim, wherein the gel comprises a thermoplastic triblock copolymer having relatively hard end blocks and an elastomeric mid-block extended with at least 300, preferably at least 500, more preferably at least 700, parts by weight of an extender liquid which softens and extends the said mid-block per 100 parts by weight of the triblock copolymer, the amount of extender liquid not exceeding 5000 parts by weight per 100 parts of the triblock copolymer.

16. A tape or sheet according to claim 15, wherein the triblock copolymer has polystyrene or polyalkylmethacrylate end blocks, and has a polyalkylene (hydrogenated or not) mid-block, preferably a poly(ethylene/butylene) and/or poly(ethylene/propylene) mid-block.

17. A tape or sheet according to any preceding claim, having a removable release- coated sheet or tape in contact with the surface of the gel remote from the backing.

18. A tape or sheet according to claim 17, wherein the release sheet or tape canies a plurality of separate, separately-removable sections of the gel tape or sheet.

19. A tape or sheet according to any preceding claim in substantially square or rectangular form with the length of its sides or its smaller sides being 2 to 5 cm, preferably with 1 to 3 mm or 4 to 6 mm gel thickness.

20. A tape or sheet according to any preceding claim, having at least one slit or aperture for positioning around an object which is to project through the tape or sheet in use.

21. A tape or sheet according to any preceding claim marked for separation into smaller portions.

22. A tape or sheet according to any preceding claim in a dispenser for dispensing and cutting off selected portions of the said tape or sheet.

23. A tape or sheet according to any preceding claim, arranged to seal a depression or aperture with the gel bridging and adhering to all edges thereof, the aperture preferably being in a three-dimensionally-concave co er of a casing for thermally- insulated white goods.

24. A method of sealing an aperture in a three-dimensionally concave comer of a hollow body, comprising pressing into the said comer a patch of a tape or sheet according to any of claims 1 to 19, thus causing the gel to adhere the patch to the intemal surfaces of the hollow body so as to seal off the said aperture from flowable material to be introduced subsequently into the hollow body.

25. A tape or sheet according to any of claims 1 to 19, wrapped around an object extending through an aperture so that one or more layers of the tape or sheet fill the space between the object and the inner circumference of the aperture.

26. A method of making a tape or sheet according to any preceding claim, comprising melt-extmding a tape or sheet of the gel (preferably continuously) into contact with a tape or sheet of the backing.

27. A method according to claim 26, wherein the extmded gel is contacted with the backing at a temperamre sufficient to produce surface melting but not complete melting of the backing.

28. A method according to claim 26 or 27, wherein the backing is also extmded. and fed continuously from the extmder into contact with the separately-extruded gel.

29. A method of making a tape or sheet according to any of claims 1 to 19 comprising co-extmding the backing and the gel.

30. An unsupported elongate article composed of oil-extended triblock copolymer gel comprising at least 15%, preferably at least 20%, by weight (based on the weight of the whole gel composition) of a styrene-hydrogenated alkylene-styrene triblock copolymer.

31. An article according to claim 30, wherein the gel comprises not more than 35%, preferably not more than 30%, possibly not more than 25%, by weight (based on the weight of the whole gel composition) of the triblock copolymer.

32. An article according to claim 30 or 31, wherein the proportion of the extender oil in the gel is within the range from 85% to 65%, preferably 80 to 70%, more preferably 80 to 75%, by weight based on the whole gel composition.

33. An article according to claim 30, 31, or 32, in the form of a roll having adjacent layers of the gel article in direct contact with one another, the tensile and/or coherent strength of the gel being sufficient to enable the article to be unrolled substantially without tearing.

34. An article according to any of claims 30 to 33, which is capable of self support when suspended for 30 seconds at room temperamre in horizontal lengths of at least 10cm, preferably at least 30cm, more preferably at least 50cm.

35. A method of sealing the space between the inner circumference of an aperture and the outer surface of an object extending through the aperture, comprising, the steps of wrapping an unsupported article (preferably a sheet or tape) of gel around a portion of the object which is to be within the aperture, moving the wrapped portion of the object into the aperture, and causing the wrapped gel to seal the said space.

36. A method according to claim 35, wherein the gel is an oil-extended triblock copolymer gel and comprises at least 15%, preferably at least 20%, by weight (based on the weight of the whole gel composition) of a styrene-hydrogenated alkylene-styrene triblock copolymer.

37. A method according to claim 35 or 36, wherein the gel is an oil-extended triblock copolymer gel and comprises not more than 35%, preferably not more than 30%, more preferably not more than 25%, by weight (based on the weight of the whole gel composition), of a styrene-hydrogenated alkylene-styrene triblock copolymer.

38. A method according to claim 35, 36, or 37, wherein the proportion of the extender oil in the gel is within the range from 85% to 65%, preferably 80 to 70%, more preferably 80 to 75%, by weight based on the whole gel composition.

39. A method according to any of claims 35 to 38, wherein the wrapped gel sheet or tape is forced-fitted into the aperture.

40. A method according to any of claims 35 to 39, wherein, after moving the wrapped portion of the object into the aperture, a portion of one or more layers of the wrapped gel protmding from the aperture is folded outwards from the said object into contact with an extemal surface of the stmcmre containing the aperture.

41. A method according to any of claims 35 to 40, wherein one or more compression members are fitted around the said object to compress the gel against the stmcmre containing the aperture.

42. A method according to any of claims 35 to 41, wherein the said unsupported article of gel is an article according to any of claims 30 to 34.

43. A tape or sheet according to any of claims 1 to 19 carrying the said gel sealant on both main surfaces of the said backing.

44. A tape or sheet according to claim 43, wherein the said backing is replaced by a foraminated or net-like reinforcing sheet.

45. A tape or sheet according to any of claims 1 to 19 carrying an adhesive, preferably a pressure-sensitive adhesive, on the surface of the said backing remote from the said sealant (preferably gel).

46. A tape or sheet according to claim 45, when attached by the said adhesive to a surface of an object which is to carry the said sealant (preferably gel) in service.

47. A tape or sheet according to claim 43, or having gel and/or backing thicknesses different therefrom, wherein the gel sealant canied on one main surface of the said backing is different from the gel sealant canied on the other main surface of the said backing.

48. A tape or sheet according to claim 44, or having gel and/or backing thicknesses different therefrom, wherein the foraminated reinforcing sheet is formed of reticulated polymeric foam, preferably of average pore size within the range from 3.9 to 11.8 pores per centimetre (10 to 30 pores per inch), more preferably 5.9 to 9.8 pores per cm (15 to 25 pores per inch), especially 7.9 ⁺/- 0.8 pores per cm (20 ⁺/- 2 pores per inch)

49. A tape or sheet according to claim 48, wherein the gel sealant at least partly, preferably substantially completely, fills the space within the foam sheet.

50. A tape or sheet according to claim 48 or 49, wherein the gel sealant extends beyond one or both main surfaces of the foam sheet at rest.

51. A tape or sheet according to any one of claims 48 to 50, wherein the gel sealant comprises a thermoplastic elastomer triblock copolymer having relatively hard end blocks and an elastomeric mid-block extended with at least 900, preferably at least 1300, more preferably at least 1800, parts by weight of an extender liquid, which extends and softens the said mid-block, per 100 parts by weight of the triblock copolymer, the amount of extender liquid not exceeding 10000, preferably not exceeding 7500, more preferably not exceeding 5000, parts by weight per 100 parts by weight of the triblock copolymer.

52. A tape or sheet according to any of claims 1 to 23, 43, and 47, or having gel and/or backing thicknesses different therefrom, wherein the said backing is a polymeric (preferably closed cell) foam and the gel sealant adheres to its surface(s) substantially without penetrating it.

53. A tape or sheet comprising an elongate body of gel attached substantially only to a lateral edge of a canier strip or sheet extending alongside the said body of gel.

54. A tape or sheet according to claim 53, wherein the said body of gel is attached substantially only to opposed lateral edges of two such carrier strips or sheets, preferably extending on substantially opposite sides of the body of gel.

55. A tape or sheet according to claim 54, wherein the two canier strips or sheets lie in substantially the same plane as each other.

56. A tape or sheet according to any of claims 53 to 55, wherein the said body of gel is of tape-like or sheet-like form and lies in substantially the same plane as the canier strip(s) or sheet(s).

57. Use of an unsupported elongate gel article of appropriate cross-sectional profile, preferably an article according to any of claims 30 to 33, in a housing component for electrical or other apparams, preferably a headlamp housing component, the gel article being positioned in the housing component so as to be capable of making a seal between the housing component and another body with which the housing component will be assembled in use.

58. Use according to claim 57, wherein the said gel article is formed in situ in or on the housing component by melt application of a gel-forming composition thereto.

59. Use of a non-aqueous gel, preferably a substantially hydrophobic gel, more preferably an oil-extended triblock copolymer gel, especially a gel of substantially smooth, glossy surface appearance, in an aqueous acid or alkali environment, preferably in an electrical battery or dry cell.

60. Use according to claim 59, for sealing electrolyte compartments or baniers within a battery or dry cell, the gel preferably being held under compression to maintain the seal.

61. An electrical battery or dry cell incoφorating seals formed by non-aqueous gel, preferably substantially hydrophobic gel, more preferably an oil-extended triblock copolymer gel, especially gel of sunstantially smooth, glossy surface appearance, in contact with the electrolyte of the battery or cell, the gel preferably being held under compression to maintain the seals.

62. Use of a sheet or tape or layer of oil-extended triblock copolymer gel in face-to- face contact with a printed circuit board, the gel being capable of conducting away heat generated in use in components of the circuit board with which the gel is in contact, the gel preferably containing fillers which increase its thermal conductivity by at least 20% , preferably at least 35%, more preferably at least 50% , over that of the unfilled gel of the same stiffness (dynamic storage modulus) as the filled gel.

63. Use of a (preferably elongate) body of oil-extended triblock copolymer gel as packing in a sealing gland sunounding a member, preferably the mast of a boat, which in use is substantially stationary relative to the gland.

64. Use of a foraminated tape or sheet, preferably of flexible foamed polymeric material, at least partly filled with gel, preferably according to any of claims 48 to 50, as a mat.

65. A frame or support stmcmre for a window or a glazed door having at least one gel seal (a) between abutting components of the said stmcmre or (b) between a component of the said stmcmre and (i) adjacent glazing of a window or door or (ii) an adjacent surface of a building in which the said stmcmre is incoφorated.

66. A stmcmre according to claim 65, wherein the gel seal is positioned so that the gel will be substantially shielded from exposure to sunlight at least when the said stmcmre is incoφorated in a building.

67. A stmcmre according to claim 65 or 66, wherein the gel seal comprises a thermoplastic gel, preferably an oil-extended hard-block-elastomeric block-hard block triblock copolymer gel, more preferably one in which the hard end blocks comprise polystyrene or polyalkylmethacrylate and/or the elastomeric mid-block comprises hydrogenated or unhydrogenated polyalkylene, preferably polyethylene/butylene and/or polyethylene propylene.

68. A stmcmre according to claim 65, 66, or 67, wherein the gel seal comprises a tape or sheet or other article according to any of claims 1 to 23, 30 to 34, or 43 to 56.