WO1997035126A1

WO1997035126A1 - Gel-carrying elongate articles

Info

Publication number: WO1997035126A1
Application number: PCT/GB1997/000773
Authority: WO
Inventors: Philip James Hammond; Ian Drinkwater; Iain Laird
Original assignee: Raychem Limited
Priority date: 1996-03-21
Filing date: 1997-03-20
Publication date: 1997-09-25
Also published as: AU2035697A; GB9605897D0

Abstract

Gel-carrying sealant profiles having a C-, V-, or U-shaped plastics channel carrier with gel on its external and/or internal surfaces for sealing between opposed surfaces of structures such as equipment housings or doors and windows. The profiles may have a projecting formation, preferably integral with the carrier, for fixing the profile to an object, e.g. by means of an enlarged portion of the formation being received in an aperture in the object. Carriers in a form similar to known 'flipper' seals are especially useful for door and window seals or other multi-entry closures. Preferred gels are triblock or multi-block copolymers having a highly oil-extended polyalkylene elastomeric mid-block and harder end blocks, preferably of polystyrene or polyalkylmethacrylate.

Description

GET -CARRYING FT .ONO ATE ARTICLES

This invention relates to articles comprising an elongate plastics carrier carrying gel, commonly referred to as "gel profiles".

Gel profiles in which the gel is carried on an elongate plastics carrier having a hollow tubular interior bore are described in our co-pending International Patent Applications Nos. PCT/GB95/02143 (RK508) and PCT/GB95/02881 (B288). The present invention relates to gel profiles of novel configurations, which may be useful for sealing or other purposes different from and/or similar to those described in those applications.

A first aspect of the present invention accordingly provides a free-standing article comprising a substantially solid, elongate, open-ended or closed-ring, channel-shaped plastics carrier carrying gel on at least part of its interior and/or exterior surface.

It is to be understood that the "channel-shaped" carriers of this and other aspects of the present invention are of substantially fixed end-cross-sectional form and do not include carriers which are intended to open or close like a book or clam shell around articles to be protected, for example wiring splices or branch-off connections. This does not, however, exclude the possibility of some flexibility in the plastics walls forming the channel-shaped carrier.

The reference to a "free-standing" article is intended to exclude elongate articles, for example wires or cables, which happen to be enclosed in a gel-containing enclosure, and are therefore in contact with the gel only as a result of being in the enclosure. The free-standing articles of the present invention may in some forms be provided in a coil or roll from which the profile article may be progressively unwound. In this case, d e gel preferably adheres more strongly to the carrier than it does to itself on interfacial contact and preferably has cohesive strength greater than its adhesive strength to itself, possibly also greater than its adhesive strength to the carrier. The reference to a substantially solid carrier excludes the hollow-bored carriers described in the aforementioned co-pending applications. Reference to an elongate, open-ended channel is intended to exclude the relatively short-length half-shells and similar trough-like receptacles having closed ends, which are filled with gel in some gel-containing cable enclosures. The reference to a closed-ring channel-shaped carrier is not intended to limit this form of the carrier to circular rings, since angular, oval, or irregular rings may also be useful in some circumstances, although substantially circular rings may be preferable for many purposes. The gel being carried on the "interior or exterior" surface of the carrier will be understood as referring respectively to the convex and concave surfaces of a rounded C- shaped carrier and to the corresponding inner and outer surfaces of other carrier channel shapes.

A second aspect of the present invention provides a free-standing article comprising an elongate, open-ended or closed-ring, channel-shaped plastics carrier carrying gel on at least part of its exterior surface.

A third aspect of the present invention provides a free-standing article comprising an elongate, open-ended or closed-ring, channel-shaped carrier carrying on at least part of its interior and/or exterior surface a layer of gel whose thickness in a direction normal to the underlying carrier is not greater than twice that of the underlying carrier, preferably not greater than that of the underlying carrier. Thicker coatings or irregular bodies of gel, or internal fillings or part-fillings of gel are not, however, excluded, and may be preferred for some purposes.

A fourth aspect of the present invention provides a free-standing article comprising an elongate, open-ended or closed-ring channel-shaped carrier of substantially uniform circumferential wall thickness carrying gel on at least part of its interior and/or exterior surface. The reference to circumferential wall thickness is intended to refer to the Λickness of the channel wall extending around the interior space of the channel, as viewed from one end or in end-wise cross-section. Preferably, the channel wall thickness will also be substantially uniform along the length of the carrier. Substantial uniformity will preferably mean less than 20%, more preferably less than 10% , variation in thickness, except perhaps at the outer ends of the channel, which may be diickened or tapered or otherwise varied for aesthetic or functional reasons.

For many end uses of the gel profile articles according to the present invention, it may be preferred that the carrier is sufficiently flexible to enable an open-ended length of the article to be wrapped at least 90°, preferably 180°, around a circular shaft of diameter 100 cm, preferably 50 cm, more preferably 25 cm, especially 10 cm, without breaking the carrier. In other instances, more rigid discrete lengths of a carrier may be preferred, for example to protect edges of sheet materials, which may be resiliently gripped by the channel opening. It may be found convenient that the carrier is formed of extruded plastics, preferably a polyolefin or an olefin/ester copolymer. It may also be convenient for the carrier and the gel to be co-extruded, suitable extrusion equipment and mediods being generally known.

Articles according to any aspect of the present invention may be provided in the form of a closed ring formed by joining together the ends of an originally open-ended length of the article, for example by adhesive bonding, e.g. using cyanoacrylate or contact adhesives and/or by melt-bonding together of the gel at the joined ends. It has been found that melt-bonding can provide a surprisingly strongly-bonded ring structure, and a separate aspect of the present invention accordingly provides an elongate article comprising gel, with or without a support or carrier, which has been formed into a closed ring by a process including bringing its respective ends into contact with each other and melt-bonding the gel together at the contacting ends. This may be especially useful for forming closed ring structures of the unsupported gel profiles described and claimed in our co-pending British Patent Application No. 9524000.8 (RK532 GB2), the disclosure of which is incoφorated herein by reference.

Alternatively, in articles according to any of the aspects of the present invention, the carrier may be a moulded closed ring, preferably having the channel opening facing inwards. The opening may also face directly outwards from the geometrical centre of the ring, or may face laterally to one side or me other of the plane of the ring at whatever angle may suit the proposed end use. It will be understood that moulding of such a ring structure is facilitated by the channel formation allowing the moulded article to be formed and removed from the mould by traditional moulding techniques. The resulting ring- shaped channel profiles are thus considerably easier to manufacture than a corresponding hollow ring of closed cross section in which the intemal hollow space is entirely surrounded by the carrier polymer. If the carrier is moulded, whether in ring formation or not, the gel may also be co-moulded with it.

In some aspects of the present invention, the gel may be carried substantially only on the interior surface of the carrier or substantially only on the exterior surface of the carrier. The position and extent of coverage of die gel will naturally depend on the intended end use of the article. A gel coating on the exterior surface of the carrier might for example be used to provide a soft, non-skid traction jacket on a wheel or roller, whereas interior gel coatings might be useful for sealing around other elongate objects such as pipes or cables. It may also or altematively be preferred that the gel is of substanitally uniform circumferential thickness, preferably forming an open channel shape corresponding to that of the carrier. It will be understood that the open channel shape formed by d e gel may either resemble an internal lining on the underlying interior surface of the carrier, or may conversely resemble an external gel channel having an interior "lining" of die carrier material.

Although the exact cross-sectional shape of die profiles according to this invention is not critical, it may often be preferred mat me end cross-section of die carrier is substantially a rounded or sharp-cornered C, V, or U-shape, with or without re-entrant or divergent formations at one or both ends. Thus, e carrier end cross section may resemble a round- or square-comered C or U facing in any direction, for example up, down or backwards or me normal direction of such a letter, or similarly may resemble a sharp or rounded V. Omer cross sectional shapes and assemblies of two or more such shapes connected integrally or adhesively side by side are not however excluded. One or bom outer ends of me cross sectional shape, corresponding to me outer tips of e "letters" may comprise divergent or re-entrant formations, for example converting the letter C into a G or otiier re-entrant shape, and/or the arms of a U-section may converge inwards towards each other, without departing from the general principle of me open channel formation.

The width of the longitudinal channel opening is also not critical, and it may in some circumstances be desirable that the longitudinal channel opening is a substantially closed slit or is of widtii less than V₈ of the maximum internal widtii of the carrier measured in a plane substantially parallel to the plane of the slit width. Such a substantially closed or relatively narrow channel opening may be useful, for example, in enabling the carrier to grip the edge of an article inserted therein, for example to provide the aforementioned wheel covering or to provide a gel buffer or corrosion protection on the edge of a sheet-like object. In other cases, wider channel openings may be needed, and it may be preferred that the longitudinal channel opening is of width at least V₈, preferably at least , more preferably at least V2, of the maximum internal width of me carrier measured in a plane substantially parallel to the plane of the slit width. In some cases it may be especially useful that the longitudinal channel opening is of width at least ³A of, or substantially equal to, the said maximum internal width of the carrier.

It should, however, be understood that the channel-shaped carrier according to the various aspects of the present invention will preferably not include very shallow articles, which might more correctly be regarded as slightly curved or bent sheets. It is therefore preferable that me longitudinal channel opening is of widtii not greater than four times, preferably not greater than three times, more preferably not greater than twice, the maximum depth of the channel perpendicular to the plane of the channel opening, preferably at the mid-point of the said opening. It will be understood that, as the channel opening width increases beyond four times the maximum depth, the channel will become progressively shallower, approaching the aforementioned curved sheet structure in the case of a smoothly-curving C- or U-shaped channel. However, shallower channels are not necessarily excluded, especially those having clearly defined corners or re-entrant ends. While the exact formation or arrangement of the gel on the carrier is not critical, it will often be preferred that the gel extends substantially continuously along a majority or substantially the whole length of the carrier and/or extends substantially continuously around a majority or substantially the whole interior and/or exterior circumference of the carrier.

Various known gel materials may be suitable for the profiles according to the present invention, preferably meeting the criteria indicated in EP-A-0426658 (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. Accordingly, it is preferred that the gel is thermoplastic, preferably comprising an oil-extended hard block- elastomeric block-hard block triblock copolymer, more preferably comprising such a triblock wherein the hard end blocks comprise polystyrene or a polymethacrylate and the elastomeric mid-blocks are hydrogenated or unhydrogenated polyalkylene blocks, preferably polybutadiene, polyisoprene, or more preferably polyethylene/butylene and/or polyethylene/propylene. Polymethacrylate triblocks are described, for example, in our co¬ pending British Patent Application No. 9512125.7 (RK509), the disclosure of which is incoφorated herein by reference.

In the profiles according to the present invention, the carrier may comprise two or more channel-shaped formations extending substantially parallel to one another, preferably within a single integral carrier member, and any of the aforementioned arrangements and characteristics of the gel component may be applied in any combination to any one or more of the multiple channels. The multiple-channel carriers may be formed as a single integral component, for example by extrusion or moulding, or may be formed by fixing together, for example by means of adhesive or melt-bonding, two or more separately-formed channel members.

In a further useful aspect of the present invention, the profile article includes a formation, preferably integral with the channel-shaped carrier of the articles hereinbefore described, for attaching the articles to an object which is to carry them in use. The said formation preferably comprises a projection with an enlarged region receivable in use in an aperture in the said object to anchor the article thereto. These articles with the attaching formations may be useful inter alia as door or window seals or gaskets, especially when the said formation is carried by a C-, V-, or U-shaped carrier arranged to resemble the so-called "flipper" gaskets known (without gel) for such puφoses. The gel will preferably be carried on the exterior surface of the channel-shaped carrier in such "flipper" seals, but may be on any surface of the carrier which enables it to make contact with the surfaces to which a seal is to be effected in use.

Specific embodiments of the present invention will now be described by way of example with reference to the accompanying drawings wherein :-

Figure 1 shows schematically a shallow C-shaped channel profile internally coated with gel;

Figure 2 shows an end view of a shaφ-cornered V-shaped profile;

Figure 3 shows a schematic end view of a round-comered V-shaped profile with re-entrant ends;

Figure 4 shows schematically in partial cross section a C-shaped profile externally coated with gel providing a jacket on a rotatable wheel;

Figure 5 shows schematically an end view of a convergent, angular-C-shaped profile gripping the edge of a sheet material;

Figure 6 shows a conjoined pair of shaφ-cornered U-shaped channel profiles;

Figure 7 shows a generally C-shaped profile with re-entrant ends having the gel on only part of its exterior surface;

Figure 8 shows schematically in perspective and plan view a circular closed-ring profile according to the present invention;

Figure 9 shows the C-shaped cross-section of the circular profile on the lines B-B of figure 8;

Figure 10 shows a corresponding cross-section of an alternative circular profile in which the channel opening faces laterally out of the plane of the ring;

Figure 11 shows a square-cornered variation of the profile shown in Figure 9;

Figure 12 shows schematically in cross-section a C-shaped profile having the aforementioned projection for fixing it to an object; and Figure 13 shows one form of the aforementioned "flipper" seal profiles with attachment projection corresponding to that of Fig. 12.

Referring to Figure 1, the shallow C-shaped carrier 10 of extruded ethylene/vinyl acetate copolymer, has been separately melt-coated with a layer 12 of a known gel comprising oil-extended styrene-ethylene/propylene-styrene triblock copolymer as described in the aforementioned WO-A-9323472. As shown in Figure IB the width w of the channel opening is approximately four times the maximum peφendicular depth d of the channel carrier, thus illustrating the preferred lower limit of channel depth, at least for smoothly curved profiles of this kind.

Figure 2 shows a shaφ-cornered V-shaped carrier partly filled with an irregular body of gel 22, in which the channel opening width w is slightly less than the peφendicular depth d. The broken lines in Figure 2 indicate a wider, shallower version of the same profile, in which the opening with w' is about four times the maximum peφendicular depth d again representing the preferred lower limit of depth or shallowness for this type of profile.

Figure 3 shows a round-cornered B-shaped extruded carrier 30 having shaφ cornered re-entrant bends 32, such that the width w of the channel opening is about ³A of the maximum intemal width W of the carrier. The internal coating of gel 34 in this example covers the interior surface of the carrier with a substantially uniform layer to approximately the depth of the re-entrant portions 32. A substantially closed slit opening 36 is indicated as an alternative by the broken lines 37 extending the re-entrant portions towards each other, and a variant in which the carrier thickness need not be constant is indicated as a bulbous thickening of the carrier by broken lines 38.

In Figure 4, a closed-ring circular C-shaped carrier 40 with an extemal coating of gel 42 is shown in position around the circumference of a wheel 44 of rotatable shaft 46, the carrier resiliently gripping the wheel as shown, so that the gel may act as a soft, non- slip surface on the wheel. Figure 5 shows schematically in partial cross-section a substantially longitudinally rigid, angular, convergent-C-shaped carrier 50 with divergent ends 51 gripping the edge of a sheet of material 54, for example glass or metal, with gel filling 53 encapsulating the sheet edge to act as a protective edge buffer and/or corrosion-preventing seal.

Figure 6 shows a carrier 60 providing two channels of square-comered U-shape, in which the channel opening width w is substantially equal to the maximum internal width. The second, smaller channel is formed by an outer wall 62 and an inner wall 64 which it shares with the larger channel, the possibility of these two channels being formed separately and then joined together by adhesive or fusion bonding being indicated by the broken line in the shared wall. The gel 66 in the larger channel illustrates the possibility that the gel thickness t may be larger than the thickness c of the underlying carrier wall. The gel coating 68 in the smaller channel illustrates the possibility of the progressively varying gel thickness.

Figure 7 shows a re-entrant C-shaped (or, perhaps, G-shaped) carrier 70, whose re-entrant ends 72 go so far as to turn back inwards towards the floor of the channel, leaving a channel opening width w about half the maximum intemal width W, perhaps to grip an object on which the profile is to be fitted in use. Layers of gel 74 are provided only on parts of the exterior carrier surface, possibly to provide a grip-promoting surface when the profile is fitted on the aforementioned object.

The ring-shaped profile 80 of Figure 8 may have the carrier opening facing inwards or downwards as illustrated respectively by the carrier 82 in Figures 9 and 10 and the profile may have square comers as illustrated by the carrier 83 in Figure 11, all of which may be produced by the aforementioned moulding or end-bonding techniques and may have the gel coating 85 on the inside as well as, or instead of, the outside as illustrated. In Figure 12, inter-fitting parts 164, 165 of a stmcture, for example an equipment housing, are shown with a profile according according to the invention attached to the lower (as shown) part 164. The C-shaped profile carrier 160 has an integral projection 162 which is received in an aperture 163 in the part 164, the projection being shaped with an enlarged head to anchor it in the illustrated constricted neck of the aperture. On closing together of the parts 164, 165, the carrier 160 will be deformed and the gel 166 which it carries will seal against the part 165. In the generally corresponding view of Fig. 13, a V-shaped "flipper" seal carrier 260 carries gel 266 on its exterior surface to seal against a surface of sliding door or window structure 265 when closed together with the receiving part 164 of the structure.

Claims

Claims ;-

1. A free-standing article comprising a substantially solid, elongate, open-ended or closed-ring, channel-shaped plastics carrier carrying gel on at least part of its interior and/or exterior surface.

2. A free-standing article comprising an elongate, open-ended or closed-ring, channel-shaped plastics carrier carrying gel on at least part of its exterior surface.

3. A free-standing article comprising an elongate, open-ended or closed-ring, channel-shaped carrier carrying on at least part of its interior and/or exterior surface a layer of gel whose thickness in a direction normal to the underlying carrier is not greater than twice that of the underlying carrier, preferably not greater than that of the underlying carrier.

4. A free-standing article comprising an elongate, open-ended or closed-ring, channel-shaped carrier of substantially uniform circumferential wall thickness carrying gel on at least part of its interior and/or exterior surface.

5. An article according to any preceding claim, wherein the carrier is sufficiently flexible to enable an open-ended length of the article to be wound at least 90°, preferably 180°, around a circular shaft of diameter 100 cm, preferably 50 cm, more preferably 25 cm, especially 10 cm, without breaking the carrier.

6. An article according to any of claims 1 to 4, wherein the carrier is substantially longitudinally rigid, preferably having sufficient channel wall flexibility to enable it to grip an object of width greater than the channel opening to be inserted therein in use.

7. An article according to any preceding claim, wherein the carrier is formed of extruded plastics, preferably a polyolefin or an olefin/ester copolymer.

8. An article according to claim 7, wherein the carrier and the gel have been co- extruded.

9. An article according to any preceding claim in the form of a closed ring formed by joining together the ends of an originally open-ended length of the article, preferably with melt-bonding together of the gel at the joined ends.

10. An elongate article comprising gel, with or without a support or carrier, which has been formed into a closed ring by a process including bringing its respective ends into contact with each other and melt-bonding the gel together at the contacting ends.

11. An article according to any of claims 1 to 5 wherein the carrier is a moulded closed ring, preferably having the channel opening facing inwards.

12. An article according to claim 11, wherein the gel has been co-moulded with the carrier.

13. An article according to any preceding claim, wherein the gel is carried substantially only on the interior surface of the carrier or substantially only on the exterior surface of the carrier.

14. An article accordingly to any preceding claim, wherein the gel is of substantially uniform circumferential thickness, preferably forming an open channel shape corresponding to that of the carrier.

15. An article according to any preceding claim, wherein the end cross-section of the carrier is substantially a rounded or shaφ-cornered C, V, or U shape, with or without re¬ entrant or divergent formations at one or both ends.

16. An article according to any preceding claim, wherein the longitudinal channel opening is a substantially closed slit or is of width less than V_g of the maximum internal width of the carrier measured in a plane substantially parallel to the plane of the slit width.

17. An article according to any of claims 1 to 15, wherein the longitudinal channel opening is of width at least V₈, preferably at least '4, more preferably at least ^lA, of the maximum internal width of the carrier measured in a plane substantially parallel to the plane of the slit width.

18. An article according to claim 17, wherein the longitudinal channel opening is of width at least % of, or substantially equal to, the said maximum intemal width of the carrier.

19. An article according to any preceding claim, wherein the longitudinal channel opening is of width not greater than four times, preferably not greater than three times, more preferably not greater than twice, the maximum depth of the channel peφendicular to the plane of the channel opening, preferably at the mid-point of the said opening.

20. An article according to any preceding claim, wherein the gel extends substantially continuously along a majority or substantially the whole length of the carrier and/or extends substantially continuously around a majority or substantially the whole interior and/or exterior circumference of the carrier.

21. An article according to any preceding claim, wherein the gel is thermoplastic, preferably comprising an oil-extended hard block-elastomeric block-hard block triblock copolymer, more preferably comprising such a triblock wherein the hard end blocks comprise polystyrene or a polymethacrylate and the elastomeric mid-blocks are hydrogenated or unhydrogenated polyalkylene blocks, preferably polybutadiene, polyisoprene, or more preferably polyethylene/butylene and/or polyethylene/propylene.

22. An article according to any preceding claim, wherein the carrier comprises two or more channel-shaped formations extending substantially parallel to one another, preferably within a single integral carrier member.

23. An article according to any preceding claim, wherein the carrier comprises polymeric foam material, preferably closed-cell foam, into which the gel substantially does not penetrate.

24. An article according to any of the preceding claims, which includes a formation, preferably integral with the channel-shaped carrier of the article, for attaching the article to an object which is to carry it in use.

25. An article according to claim 24, wherein the said formation comprises a projection with an enlarged region receivable in use in an aperture in the said object to anchor the article thereto.

26. An article according to claim 24 or 25, wherein the carrier constitutes a "flipper" seal for doors or windows or other multi-entry closures, with the gel on the exterior surface of the "flipper".