The present invention relates to a recoverable article, especially one recoverable by virtue of recoverable fibres thereof, for covering a substrate to provide that substrate with a particular kind of surface. The article may therefore serve as a hand-grip for use on racquets etc. The invention will be described principally in terms of a hand-grip, but it may be used for other applications where contact with the body makes surface characteristics important, or where abrasion resistance, bulk or other properties are required.

A dimensionally-recoverable article is an article whose dimensional configuration may be made to change substantially when subjected to heat or other treatment. Usually such articles recover towards an original shape from which they have previously been deformed, but the term "recoverable" as used herein also includes the ability to adopt an entirely new configuration. This will generally be the case when a fabric is produced from a recoverable fibre.

Recoverable articles in general, and recoverable fabrics in particular, are well known for packaging and for environmental sealing. Reference may be made to EP-B-0115905 (Raychem Limited) which discloses a recoverable fabric particularly suitable for use in enclosing a splice between cables. A fabric is used therefore because of its creep resistance and split resistance, and the final product will, generally as a result of the presence of a matrix material, be highly impermeable.

The principal reasons for the present use of a fabric are, however, entirely different. Two reasons may now be mentioned for our choice of a fabric. Firstly, we are able to produce particular surface characteristics desirable in a hand-grip etc, and secondly we are able to separate various properties by providing two or more types of fibre.

Thus, the present invention provides a dimensionally-recoverable hand-grip which comprises a fabric, preferably a dimensionally-recoverable fabric, and preferably one in tubular (rather than, say narrow strip) form. At present we prefer that the fabric comprise a woven fabric but for some purposes non- woven, knitted, braided or other fabrics may be

used. The size of the grip will depend on the application and, although preferred, it is not necessary that the grip be of such a size that one's hand can extend completely around it. Where the fabric is to be gripped by hand a recovered diameter of 20-35 mm, preferably 25-30 mm will be suitable. A recovery ratio of at least 1.2 x preferably at least 1.4 x (change in dimension as a multiple of recovered dimension) will be suitable. Larger recovery ratios, say at least 2, 3 or 4 x may be desirable when the substrate to be covered is of non-uniform cross-sectional size. Extent of recovery may instead be quoted as a percentage (change expressed as a percentage of the original dimension). The four values quoted above would become: 54%, 58%, 75% and 80%. Much lower shrinkages such as 10 or 20% may also be provided. The length of the tube will also depend on the application. It might be relatively short when used as a racquet, but longer when used, say, around the bar of a sail board.

The present invention also provides a dimensionally-recoverable fabric, which comprises:

(a) recoverable fibres;

(b) fibres having a soft hand and/or that provide bulk in the installed fabric;

the fibres (a) and fibres (b) being so interlaced with each other or with third fibres, preferably by weaving, that after recovery predominantly fibres (b) stand proud of fibres (a) at that surface of the fabric that is outwardly-facing when in use.

The fibres that provide bulk may do so as a result of their nature (eg they have been texturized) and/or as a result of the fabric design by which they have been incorporated into the fabric.

In a preferred embodiment the fabric additionally comprises:

(c) heat-activatable (for example hot-melt or curable) adhesive fibres;

fibres (c) being so positioned that they are present predominantly at a surface of the fabric that is inwardly-facing when in use.

In this way the fabric can be positioned around the substrate to be covered then heated, whereupon it will shrink into engagement with the substrate and become bonded to it. The adhesive fibres may be interlaced at high float, for example a float of at least three, preferably at least five, with other fibres such that the adhesive fibres are present predominantly at said surface that is inwardly-facing. Alternatively, or additionally, a dual or other multi-layer fabric may be produced with, for example, an inner or other layer comprising mainly adhesive filaments or other fibres. In a further alternative or addition adhesive or other fibres may be held to an outer surface etc. by "self-stitching" fabric construction or by a binder or stitching fibre.

The invention further provides a tubular fabric produced on a narrow fabric loom comprising dimensionally-recoverable weft fibres, and substantially non-recoverable warp fibres of soft hand.

The invention also provides sports equipment (such as bats, racquets and clubs etc), tools or control levers, and vehicles (such as bicycles, sail-boards, hang-gliders etc) having a hand grip or fabric according to the invention. The fabric may be used for other surfaces intended to abut the human body, particularly where comfort or feel, or size build-up or insulation is important, such as seats, seat backs, rests or restraints, crutches, wheelchairs and walking sticks etc.

It can be seen therefore that the present invention, by the use of different types of fibres, allows the provision of a particular surface to be separated from, for example, means for attaching that surface to the substrate to be covered. Two preferred means for attachment are mentioned above, namely recoverability and adhesion. The characteristics of the surface may result from the weave (or other fabric) design, giving rise to surface ribs or stipples etc. Alternatively or additionally the surface may result from the type of fibres used, for example a surface predominantly of cotton or fine fibres may be produced. Depending on the intended field of use it may be desirable that the hand-grip, and in particular the fabric comprising it, be air-permeable at least after recovery. For some uses it may be desirable that the hand-grip, and again in particular the fabric comprising it, be able to absorb sweat or other moisture. For some uses, however, it may be preferred that the material be non-absorbent.

The hand-grip may consist substantially entirely of fibrous material, although it may contain other material, for example an internal laminate, by means of which it may be bonded to the surface to be covered.

The grip will preferably be in tubular form, generally recovering radially and remaining of constant length, although it may for example be biaxially or multiaxially recoverable. Thus, the grip preferably has recoverable fibres in a first direction (circumferential with respect to the tube) and substantially non-recoverable fibres (longitudinally with respect to the tube) in a substantially perpendicular direction. The fabric used will generally be woven, optionally with further fibre insertions, but it may be knitted, braided, non- woven or of net-like construction.

Various types of fibres may be used but we prefer that the recoverable fibres comprise a polyolefin such as polyethylene, or other plastics material, and such plastics material is preferably cross-linked. The recoverable fibres are preferably present as monofilaments, but in some circumstances multifilaments may be used. The substantially non-recoverable fibres will generally be chosen for their feel and a material of soft hand is preferred such as cotton or other natural material. Synthetic fibres commonly used for clothing fabrics may, however, be used. The example one may use synthetic fibres which have been texturized by any of various techniques to impart bulk, crimp, hand and/or feel etc. Examples of these texturing techniques include sniffer box crimping, draw texturing with friction or spindle twisting or knit-de-knit processes. An alternative technique is air jet texturing.

It might be desirable that the grip be installed at low temperatures, for example those reached using a hot-air gun rather than an open-flame torch. We have found that shrinkable fibres comprising linear low density polyethylene (LLDPE) are particularly useful, especially those comprising LLDPE having a weight average molecular weight of from 55,000 to 130,000 and a crystallinity less than 60%, such as those LLDPEs known by the Trademarks Stamylex 1064F, Stamylex 1066F and Dowlex 2288E. It is preferred that the recoverable fibres recover at a temperature significantly below that at which the cotton or other substantially non-recoverable fibres suffer damage. A significant difference between recovery and damage temperatures is desirable since quick installation

will often require heating that causes the surface of the grip to be heated far above the recovery temperature of the fibres.

It is desirable that the substantially non-recoverable fibres predominate at least on an outer surface of the grip at least after recovery. Thus, the substantially non- recoverable fibres preferably have an optical coverage of greater than 50%, preferably greater than 60%, more preferably greater than 75%, on that surface of the fabric that is outwardly facing when in use. This can result, for example, from the substantially non- recoverable fibres bunching together during recovery or from the weave design.

In order to achieve the desired feel, the substantially non-recoverable fibres may be very fine and are present as multi-filament bundles and/or as staple fibres. For certain applications rubber or other elastomeric fibres may be used.

The various fibres that make up the fabric may be interlaced in any suitable way, although we prefer that a weave be provided in which the substantially non-recoverable fibres comprise the warp or weft (preferably the warp), and the recoverable fibres comprise respectively the weft or warp (preferably the weft) of a woven fabric. A preferred weave is a 2/2 regular twill.

The fabric is preferably woven in a tubular form, although it could be woven as a flat sheet and later secured in a tubular form by tapes, tie wraps or friction closures such as Velcro closures. That would preferably be done in the factory or it could be done during installation. We particularly prefer that the fabric be woven as a tube using a narrow fabric loom. Tubes can be directly woven using a narrow fabric loom by weaving a double thickness, the weft fibres being interlaced at one edge.

Fibres may be introduced additional to the recoverable and substantially non- recoverable fibres mentioned above. Alternatively or additionally those fibres may have functions additional to those of causing recovery and providing the desired surface characteristics.

EXAMPLE

A heat-shrinkable tubular hand-grip was produced having a recovery ratio of about 1.4X, for use over a handle of diameter between 25 and 30 mm. A wider range of handle diameters could be accommodated by employing a reduced/looser endage in the warp direction. The grip had a breathable, soft and fluffy feel, and was deformable to the hand and flexible when installed with a warp cotton yarn generally predominant on the outside. Contrasting colours may be used in the make up of the warp (for example using different longitudinal strips). Company logos or names could be incorporated in the design, for example by using a Jacquard loom. The grip was installable using a high temperature hair dryer or other hot-air gun, allowing "do-it-yourself installation, retrofit or repair.

A 2/2 regular twill tube was woven on a narrow fabric loom using:

Warp yarn black cotton - total 40 end per cm (6.7 ends per surface of 2/3 s cotton count, 370 tex)

Red high density polyethylene, 0.27mm monofilament (55 tex), was used as the shrinkable fibre, at a density of 13.4 double picks per cm ie 6.7 insertions per surface (narrow fabric needle insertion).

The woven product was irradiated to 10 mrads to cross link the polyethylene to ensure installability, with no detrimental effect on the cotton. Alternatively, the polyethylene may be irradiated before weaving.

The number of warp ends per cm can be adjusted at manufacture to ensure sufficient cover, depending on the tex of the yarns, and on feel of the grip desired. Adhesive fibres (eg. polycaprolactone) can also be incorporated into the weave structure to ensure a built-in bond to the substrate. The choice of the warp yarn would also depend on the application. For example, for sail-boards and other equipment for water sports a breathable, yet non-moisture absorbing, yarn would be desirable. Otherwise, moisture- absorbing yarns might be preferred.

Such woven tubes were shrunk around the shaft of a racquet and around the control bar of a sail board. Short lengths of heat-shrinkable tubing, optionally internally coated with a hot-melt adhesive, were shrunk over each end of each tube down onto the underlying shaft or bar in order to protect the ends of the weave.

Such fabrics also have bulk allowing them to provide various benefits additional to or instead of a desirable feel when used as a hand grip. For example they can provide some separation between an object around which they are shrunk and adjacent objects. They can also provide thermal insulation. A further use is in increasing the effective size of objects around which they are shrunk, for example making objects more easy to grip by people with arthritis etc. Separation between an object and adjacent objects may be desirable for abrasion resistance (for example ropes could be covered with the fabric of the invention), prevention of breakage (glass or other fragile articles), holding of water for cooling by subsequent evaporation, or for covering of sharp edges to prevent injury.