WO1999034972A1

WO1999034972A1 - Flexible sheet material

Info

Publication number: WO1999034972A1
Application number: PCT/GB1998/003804
Authority: WO
Inventors: Kurt David Sugden
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-12-30
Filing date: 1998-12-30
Publication date: 1999-07-15
Anticipated expiration: 2000-06-30
Also published as: GB9727469D0; GB2368040A; GB0021268D0; AU2062899A

Abstract

Flexible sheet material is impervious to water vapour and is shaped to provide, on at least one face, alternating, substantially parallel ridges (5) and valleys (6). The material has a cellular foam structure (1). The material may form a component of, for instance, articles of clothing, footwear, headgear and sound proofing and insulating material.

Description

FLEXIBLE SHEET MATERIAL

FIELD OF THE INVENTION

This invention relates to flexible sheet material which may be used in a variety of applications in which the material adds ventilating, insulating or other protective properties to an article of which it forms a part. By way of examples, the material with which this invention is concerned may be used to provide or add ventilation, insulation or other protection from various environmental conditions, including wind, rain, temperature, impact and sound.

BACKGROUND TO THE INVENTION

Numerous types of planar or sheet materials have been proposed to date in order to provide insulation from various environmental conditions. For instance such materials have been proposed for incorporation into clothing, including such items as jackets, coats, footwear and headgear. Known materials may vary considerably in their degree of flexibility, depending, amongst other things, on their location and function. In other words very different types of protective materials have been incorporated into different articles of clothing, for instance motor cycle helmets, life boat crewmen's jackets, ski boots and training shoes.

GB 1094893 discloses a lightweight laminated fabric which is suitable for outer garments and which is described as well-ventilated and having good heat-insulating properties. The fabric comprises a ply of woven textile material to which is bonded a lamina of foamed synthetic plastic material or foamed rubber having a thickness not exceeding 3mm. The foam material has a pattern of inter-communicating channels or grooves embossed in that surface which faces the ply of textile material, the later being bonded to the lands or raised areas only on the embossed surface of the foamed material so that the channels or groove foam air spaces which improve ventilation of the laminated fabric and enhance its heat-insulating properties. GB987112 discloses an insole designed to cushion and heat insulater the foot of the user, the insole being freely disposed in an article of footwear. The insole comprises a perforated cover sheet and a thicker layer of homogeneous cushioning material underlying the cover sheet and secured thereto. Corrugations are formed in the thickness of the cushioning layer to provide a corrugated under surface to the insole. The cushioning material may be made of various suitable materials including a thermoplastic foam, such as a vinyl foam, a polyester or polyurethane foam.

US4469736 discloses a planar element for the absorption of air-transmitted sound which includes a flexible layer of open-cell foam material including a surface having protuberances with peaks formed thereon. The element further includes a flat closed cover layer formed of synthetic foil material fastened to the peaks of the protuberances.

US4690847 discloses a cold weather garment system comprising an interior lining fabric, an outer fabric and an intermediate layer of open-cell foam at least half an inch thick. One face of the foam layer is convoluted including peaks and valleys and the convoluted face is disposed in abutting relationship with the inter lining fabric.

EP0800777 discloses an innerboot, particularly for sport shoes, which is made of thermoformable material. The inner boat includes an outer lining associated with a first layer of thermoformable material having one or more holes and a second layer of transpiring material with one or more channels being formed at the second layer.

US5380578 discloses a laminated elastic fabric for use in making a material having reduced drag as the material moves through surrounding fluid. The fabric comprises a stretch fabric layer and an elastic plastic layer which is bonded to the stretch layer to form a laminate. The plastic layer includes parallel spaced grooves disposed in an outer surface thereof, the grooves having a maximum depth of 0.6mm. Although all the above-mentioned known materials consist of or include a layer having some form of convoluted face, none of these proposals disclose the essential characteristics which are required in order that a flexible sheet material can provide a satisfactory degree of ventilation, insulation or other protection against environmental conditions.

STATEMENTS OF INVENTIONS

According to the present invention there is provided flexible sheet material which is impervious to water, whether in the form of liquid or gaseous water, and which is shaped to provide, on at least one face, alternating ridges and valleys, said material being of cellular foam construction.

Such material can be incorporated into articles, such as articles of clothing or footwear, in order to provide a system in which air, water vapour, sound, impact or other undesirable effects are transmitted not through the material but are confined to that side bearing the convolutions and, where appropriate, are ducted along the channels formed by the ridges and valleys.

Particularly in the case of footwear for use in high speed activities such as running, it is preferred that the recovery time taken for a ridge, which has been substantially fully compressed in a direction towards the opposite face of the material, to return to within 95% of its original height is not more than 30 milliseconds (mS).

Slower recovery times are acceptable for footwear for walking and for other clothing, such as coats and jackets. Even slower recovery times are acceptable for sound proofing applications.

Preferably the recovery time can be maintained over a period of at least one hour during which the ridge is compressed at least once per second, more preferably at least five times per second. Preferably, the material is sealed on at least each face by means of a continuous, integral skin or film.

Preferably the material has a cellular structure, being formed of, for instance, a closed cell foam. This can be provided by, for instance, a latex-based material having an ability to withstand a temperature of at least 160°C, preferably up to about 220°C. Alternatively the foam may be foamed from a synthetic rubber material.

The cellular structure of the material should preferably be such that the material will tend to crumple on impact rather than expanding sideways, thereby reducing any tendency to sealing of the channels during compression. As the structure of the material is both cellular and corrugated, it is of light weight, highly thermally insulated, resistant to impacts and very flexible in all directions.

Material of the invention can be made using any suitable apparatus, for instance a ridged roller system. When the channels are formed during manufacture, the process produces a skin on the exterior surfaces which seals the cellular structure. The foam, comprising individual sealed cells, does not absorb liquids. However it may be additionally treated to provide fire-resistant and/or antimicrobial, including antibacterial, properties.

Preferably the material is substantially flat on one face and corrugated on the other face. Preferably the maximum thickness of the material in an uncompressed condition is from three to twelve millimetres. More preferably the maximum thickness is from 3.5 to 6mm and most preferably from 3.5 to 4mm.

Preferably the cross-sectional area of each ridge is from 75 to 125% of the cross- sectional area of each valley. Preferably the height of each ridge is at least 50% of the total thickness of the material. More preferably the height of each ridge is from 75 to 90% of the total thickness of the material.

Preferably the distance between the centre of the ridge and the centre of an adjacent valley is from 3 to 12mm.

Preferably the top of each ridge and the bottom of each valley is substantially flat.

Preferably the bottom of each valley has substantially the same width as the top of each ridge.

Preferably the sides of each ridge are parallel or converge in a direction towards the top of the ridge. More preferably, the angle of convergence is from zero to 15°.

Preferably the material has bonded to a face thereof, which face is remote from the or a shaped face, a flexible fabric support layer. This layer may stiffen the material against stretching in the plane of the material. The fabric layer may be made of, for instance, a wear-resistance permeable fabric, such as cotton or a mixture of yarns.

The fabric layer may be sandwiched between the corrugated layer and a further layer which may be, for instance, leather, rubber, impregnated cotton, a solid plastics layer or the like.

Preferably the corrugated material has bonded to the or a shaped face thereof a water- vapour permeable layer. This layer can be, for instance, an open-weave gauze-like or perforated material or, if a lesser permeability is acceptable, a microporous or microphilic type of fabric. The layer may be a combination of types of fabric to suit particular areas and types of garment. The layer may have a soft brushed pile to provide softness and comfort. Particularly in the case where the material is to be used in an item of footwear, there is preferably bonded to the or a shaped face of the material a pressure distributing layer. This may form the pressure oversole of a shoe or other item of footwear. Such a layer has some flexibility but is stiff compared with the corrugated layer. It may be made of any suitable material such as a polycarbonate. The pressure distributing layer may be such that it transmits pressure more in one direction than another. For instance, when incorporated in footwear, the pressure distributing layer may transmit pressure more longitudinally, that is to say from toe to heel, than transversely, the pressure distribution profile being that of an ellipse rather than a circle. As indicated above, flexible sheet material in accordance with the present invention may have a wide range of applications including forming parts of an article of clothing, an item of footwear and buoyancy providing articles such as life jackets. It may be incorporated in sound absorption and/or vibration dumping material.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of examples only, with reference to the accompanying drawings, in which:-

Figure 1 shows a section through a first embodiment of flexible sheet material in accordance with the invention; Figure 2 shows a section through a second embodiment of flexible sheet material in accordance with the invention;

Figure 3 shows a section through a third embodiment of flexible sheet material in accordance with the invention;

Figure 4 is a diagrammatic representation of a jacket incorporating flexible sheet materials of the invention;

Figure 5 shows detail of a venting portion of the jacket of Figure 4;

Figure 6 is a diagrammatic plan view of a footwear sole incorporating flexible sheet material of the invention;

Figure 7 is a diagrammatic cross-section of an item of footwear incorporating flexible sheet material of the invention; Figure 8 shows the flexible sheet material forming part of the item of footwear of Figure 7;

Figure 9 shows a fourth embodiment of flexible sheet material of the invention; Figure 10 shows a fifth embodiment of flexible sheet material of the invention;

Figure 11 shows a sole unit incorporating a sixth embodiment of flexible sheet material of the invention; and

Figure 12 shows a modified version of the sole unit of Figure 11.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figure 1 of the accompanying drawings, there is illustrated a two layer planar material of the invention in connection with which the trade mark Ventzeug will be used. Such material may be, for instance, that manufactured by the company James Walker and Company Ltd of Cockermouth, England.

Layer 1 is formed from a latex based compound and has a closed cell structure which is sealed by the continuous outer skins of the layer. As illustrated, one side of this layer is flat and the other is corrugated, ridges 5 and valleys 6 alternating with each other and extending parallel to each other in straight or curved lines.

The material and structure of layer 1 is selected so that the recovery time taken for a ridge, which has been substantially fully compressed in a direction towards the opposite, flat face of the material, to return to within 95% of its original height is not more than 30mS. Indeed this recovery time can be maintained over a period of at least one hour during which the ridge is compressed at least 5 times per second. The latex based material of layer 1 is such that it can withstand the temperature of at least 160°C, and, preferably, a temperature up to about 220°C.

The recovery time of the material may be measured using, for instance, apparatus which includes a low mass, hollow, rigid horizontal tube. This tube is mounted on low friction bearings allowing the tube only to move longitudinally. A pressure plate is attached at one end and material samples can be placed between this plate and a rigid anvil. Attached to the tube is a linear displacement transducer which indicates the longitudinal position of the tube by means of a voltage output. When the pressure plate is in contact with the anvil, the voltage output is recorded and subsequent positions of the tube displaced from the anvil are measured by a digital clock gauge, thereby enabling tube displacements to be accurately calibrated to 0.01mm. Thus the thickness of the material placed between the pressure plate and the anvil may be accurately measured. When a known pressure is applied to the other end of the tube, the resultant displacement can be recorded. The tube is provided with an adjustable locking and instantaneous release mechanism that enables the material compression to be set to the voltage read out that coincides with the selected pressure. The voltage from the transducer is also monitored with a digital storage oscilloscope so that, when the tube is released, the recovery and creep rate times can be very accurately measured.

As illustrated the ridges 5 and valleys 6 are substantially equal in cross-sectional areas. The width of the top of the ridge 5 is substantially equal to that of the valley 6. The sides of each ridge 5 may converge in a direction towards the top of the ridge. The flat tops of the ridges 5 facilitate bonding for any overlaying material.

The thickness 2 of the material depends upon the application but normally will range from 3 to 12mm. If greater thickness material is required for a particular application, then two or more layers of material 1 should be used.

The thickness of the base 3 of the material is normally no more than 50% of the total thickness 2, making the material resilient to stretching both laterally and longitudinally. Stretching can be controlled by the provision of a thin backing layer 4 which is bonded to layer 1 either during or after production of layer 1. The clearance angle 7, indicating the degree of convergence of the sides of ridges 5, is required for ensuring unconstrained recovery of a compressed ridge as well as to reduce the constriction in the channel when the material is compressed. Angle 7 is normally between 0 and 7.5°.

The cross-sectional areas of the ridges 5 and valleys 6 are illustrated in hatched form at 8 and are substantially equal.

Figure 2 of the accompanying drawings illustrates a second embodiment of the invention, in this case material which may be utilised in harsh weather garments such as marine jackets. In this case, layers 1 and 9 are similar to layers 1 and 4 of the Figure 1 embodiment of the invention. An additional layer 10 is attached to layer 9. Alternatively layers 9 and 10 may be combined into one material which provides both additional strength as well as a soft wear resistant outer garment skin. Layer 10 may be chosen from aesthetic reasons such as colour and/or texture.

The material of Figure 2 includes an upper layer 11 , which is bonded to the peaks of the ridges of layer 1. The bonding may be accomplished either during or after the manufacture of layer 1. Layer 12 is formed of a material which is readily permeable by water vapour. For instance the material may be of an open weave nature, designed to allow the body's water vapour to pass easily into the channels 13, or, alternatively, allow air to flow from the channels 13 to the body of the wearer of the garment. Layer 11 also functions to prevent direct contact of the body with the latex layer 1 , including rubbing of the body against the ridges of this layer. It will be appreciated that any body movement in the proximity of the material of Figure 2 will result in a movement either into or out of the channels. Since the skin of the wearer makes contact with the material both in the vicinity of the ridges and the valleys, then at least 50% of the body area has a freely venting area at any time.

When material, such as that shown in Figure 2, is utilised for sound proofing of aircraft or vehicle panels, layer 11 is itself the panel to which the remainder of the material may be bonded with an adhesive. Alternatively, since the remainder of the material has a high temperature resistance, it can be applied to the plastic panel during the manufacture of the later and while the panel is still in a semi -plastic state, thereby adhering by virtue of the stickiness of the panel in this state.

The combination of the foam layer 1 , and the provision of channels accommodating significant quantities of air, means that the material as a whole forms good sound as well as thermoinsulating properties. In addition, electrical wiring may be located, and be concealed, within the channels.

Referring to Figure 3 of the accompanying drawings, there is shown a layered material suitable to provide a simple aeration system for footwear. Layer 1 is similar to the corresponding layer 1 of the Figure 1 embodiment. Support backing layer 9 facilitates the handling of the material and the retention of the material in a cut-out shape suitable for location within an item of footwear. The layered material may be bonded to the sole 16 of the footwear. The tops 15 of the ridges of layer 1 are bonded to an over-sole layer 14 which provides pressure distribution. Oversole 14 is sufficiently flexible to suit the bending requirements of the footwear, but also has sufficient stiffness so as to distribute a point pressure over a large surrounding area. As a result, air contained in valleys 13 is easily displaced and, as the area of the valleys is substantially equal to the area of the channels, then approximately 50%> of the footwear sole is utilised to ventilate the footwear.

Referring to Figure 4 of the accompanying drawings, there is illustrated a harsh weather jacket such as is worn, for instance, for marine purposes. The jacket incorporates materials such as is shown in Figure 2. The orientation of the valleys and ridges are shown in the drawing, for example, at 17. The material is cut and butt jointed so that the air flow along the channels may be directed to selected areas, for instance, to cuff 18 where the channels are at right angles to those in sleeve 17. The outer layers (layers 9 and 10 in Figure 2) are provided with apertures 22 where a porous material may be bonded thereover to provide a simple air intake. This in turn may be provided with a covering flap 23 which may be opened fully or partially by means of, for instance, buttons, a zip fastener or a touch and close fastening such as Nelcro.

Other ventilating areas may be sited at positions where bodily movements may encourage venting, examples being as indicated at positions 20 and 28. Again covering flaps and air filters may be provided as shown at, for example, 21 and 24.

If vents are required to be in permanent operation, a double skin flap, similar to a trench coat, can be incorporated as is illustrated at 19, the flap in this case being located only on the back of the jacket. The outline of overlying material is shown at 25 and 26 and in these areas the direction of the channels is from the pocket outline 27, and the venting area 28, to the sleeve and to an arrangement similar to that illustrated at 20 and 21.

Referring to Figure 5 of the accompanying drawings, there is shown a vertical cross- section of an arrangement by which controlled venting, as well as a pocket, may be provided for a jacket of Figure 4. A water vapour permeable layer 36 lies adjacent the body 56. Layer 36 is attached to corrugated layer 34 which provides the channels 35 and which is attached in turn to the non-permeable layer 37, the latter layer provided an aesthetic appearance to the main body of the jacket. Aligned apertures at, for instance, 51, 52 and 54, extend from channels 35 through the base of layer 36 and through the permeable layer 37.

Secured to layer 37 is another piece of layered material having permeable, corrugated and non-permeable layers, all indicated as 38. In this case the direction of the channels is at right angles to the channels 35. As can be seen in Figure 5, this overlying second layered material is provided with perforations which are aligned with those of the underlying material. A layer of air filter material 41 overlies the perforations where they open on the outer face of the second layered material 38. A pocket 43 is attached to the second layered material 38 at a position above air filter material 41. Pocket 43 hangs down from position 46 and overlies air filter material 41. The pocket material 42 is turned up to provide a normal pocket facility 44 and is provided with pocket flap 45, attached to pocket 42 at position 46. A perforated spring plastic strip 47 is attached to the bottom of pocket 44 and also to the second layered material 38. It is provided with a closing flap 48 which may be controlled as to the amount of closure of the gap between the bottom of pocket 44 and the second layered material 38. With flap 48 open, the plastic strip 47 forces the bottom of pocket 44 away from second layered material 38, thereby opening reverse pocket 43. Air can enter as indicated by arrows 49 and 50, the air passing through filter 41 and the aligned perforations so as to enter channels 35 and hence to the body 56 through the permeable layer 36. Arrows 53 and 55 indicate flow of air to other parts of the jacket. The pocket type venting system described above can work in reverse for air extraction in calm conditions with the motion of the body causing venting. In another embodiment, the pocket type venting system may be constructed differently to provide two conventional double pockets for a motor cyclist in which maximum venting is provided when the motor cyclist is in a forward-leaning riding position.

Referring again to Figure 4, butt jointing of material at an acute angle results in changes of direction of the air flows contained within the channels. Such an arrangement can also be effectively utilised in the lining of footwear such as military or ski boots, thereby assisting the air to be guided away from the toe and lower areas, as well as providing additional thermal insulation and impact absorption. Similarly, butt jointing can also be incorporated into the lining of helmets, such as motor cycle helmets, as a result of which the air stream developed during motion can be guided and controlled by intake vents into the channels, or in an aircraft pilots helmet from an on board source. Furthermore, similar material can be utilised in the construction of vehicle seat upholstery which may be connected to the heating/cooling/air conditioning system of the vehicle. Referring to Figure 6 of the accompanying drawings, a layered material such as that shown in Figure 3 is in the form of a footwear sole with the channels 29 running laterally. The corrugated layer for such a sole unit can be cut from a sheet of corrugated material. Alternatively, the layer may be formed as a complete unit by, for instance, a suitable moulding technique. There is then no wastage of material and all surfaces may be provided with a smooth skin.

The layered material of Figure 6 is provided with a central longitudinal slot 30 which is connected via a one-way valve 31, through a duct 32, to an external duct 33 and hence to an intake filter housing mounted on an upper location of the footwear, for instance, at the ankle or leg region. The filter located within the filter housing may be such as to provide both dust filtration and also have a dry deodorising function provided by multiple area fragrance dispersion.

Figure 7 of the accompanying drawings shows in cross-section a typical modern moulded constructional item of footwear incorporating the sole of Figure 6 together with a heel mounted filter housing. The main sole 57 of the footwear is moulded to the footwear uppers 58 which have been lasted onto the base sole 59. The corrugated material 64 is attached to the base sole 59 leaving a small gap 68 around the periphery of the sole area. The pressure distribution sole 65 is attached to material 64 so that, when foot pressure is applied, the air contained by the channels is forced out as shown by the arrows 69. The air passes upwardly past footwear insock 66 and is dispersed about the foot. When the foot pressure is released, the materials 64 recovers to its original shape, drawing new air in through a filter cap 63, a filter located in filter housing 62, ducting 61 and one way valve 60. The filter cap 63 is provided with a water trap system which works in a similar manner as the deck ventilator on a yacht.

Figure 8 of the accompanying drawings shows an alternative corrugated sole for use in the item of footwear of Figure 7. In this case the material is formed from two pieces 70 and 71 which are abutted in a herring bone fashion. Preferably, the pieces 70 and 71 are abutted such that the ridges of one piece abut the valleys of the other piece, and vice versa. Such an arrangement helps to disperse the air in keeping with the foot pressure progression during walking or running. Air dispersion is directed more to the forward foot area. There is an increase in cross-sectional shear resistance and the material is cheaper to produce as there is less wastage.

Figure 9 of the accompanying drawings shows an enlarged diagrammatic plan of another embodiment of material of the present invention. In this case the corrugations run in a zigzag formation (see top and bottom of the drawing) or in the form of cycloid curve.

The accompanying cross-section of Figure 9 shows the ridge width A and channel width B, A + B being equal to the pitch width P. The top of the ridge D is identified also in the planned view. The ridges and channels run parallel to each other while being formed longitudinally in a cycloid curve that has a lateral pitch or deflection substantially equal to P. The chord or longitudinal length of one complete curve C is of the order of 5 to 10 times the value of P. For comparison, the tops of ridges formed in a zigzag pattern are indicated by R.

The provision of non-linear ridges and channels helps protect the material against creasing or buckling along the channels. If the corrugations are provided in a straight line, the channels tend to provide break lines promoting bending along the channels. The non-linear corrugations provide regular attachment areas for overlying materials both along and across the channel areas, at the same time providing a natural and harmonious distribution of venting areas.

The use of a corrugation pattern based upon curved channels and ridges has the least effect in reducing the air/vapour flows and provides an effective structure against impact. Furthermore the sound absorption and vibration dampening properties are improved. In addition, such a structure provides particularly ready moulding release during manufacture. Figure 10 of the accompanying drawings illustrates an enlarged cross-section of another embodiment of material in accordance with the present invention. This material consists of a base layer E which has flexible material strips G attached by bonding and/or over stitching F. A further layer of material H may be attached to layer F so as to reproduce an arrangement similar to the foam type material described above. Hollow tubular type section materials are not suitable for the strips G for use in clothing applications as they are particularly susceptible to kinking.

Referring to Figure 11 of the accompanying drawings, there is illustrated a diagrammatic plan representation of a sole unit incorporating corrugated material of the invention. The front part of the sole is similar in construction and operation to that described with reference to Figure 7 and 8. The heel area is formed with the ridges in the form of a continuous or enclosed pattern providing a valley formation 73. When the over pressure sole (item 65 in Figure 7) is attached to ridges 72, a volume of air is located within the valley system 73. When compression takes place, through, for instance, the normal walking or running of the wearer of the shoe of which the sole unit forms a part, air is driven out of the valley system 73 through one way valve 76 to the exterior of the shoe as indicated by arrow 77. Alternatively, the air may be directed to a dispersion filter located at, for instance, the highest convenient point appropriate to the type of footwear concerned.

When the pressure is released, vapours and associated liquids are drawn into the underlying ducts 78, the ends of which open into the interior of the footwear. Ducts 78 extend to a collection point or manifold 79 and from there via duct 74 and one way valve 75 into the valley system 73 of the heel. The vapours and other materials drawn into the valley system 73 in this way are then ready for dissipation on the next compression.

Referring now to Figure 12 of the accompanying drawings, the front section of a sole unit, similar to that shown in Figure 11, may be formed to provide an enclosed pressure distribution pattern. In this case it may have a valve system similar to that shown with reference to Figure 11. One way inlet valve 60 (see also Figures 7 and 8) allows air to be drawn into the cavity via filter 85. A one way outlet valve 84, located in the toe area, allows pressurised air to be dissipated, via underlying ducts 81, into the toe area as indicated by arrows 83, thereby providing a constant supply of filtered, conditioned air directly into the hot zone formed by the toe area.

The relatively large volumes of air being forced into the confined toe area produce an effective rearward airflow. This airflow is simultaneously assisted and partially extractive by the heel extraction system indicated by arrows 82, thereby providing an efficient means of internal environmental conditioning. In addition, the pressure responding sole provides great comfort as well as insulating the foot from harsh ground contact effects such as heat. Indeed, the foot is virtually walking upon a constantly replenished source of fresh conditioned air.

Claims

1. Flexible sheet material which is impervious to water, whether in the form of liquid or gaseous water, and which is shaped to provide, on at least one face, alternating ridges and valleys, said sheet material being of cellular foam construction.

2. Material according to Claim 1 and being such that the recovery time taken for a ridge, which has been substantially fully compressed in a direction towards the opposite face of the material, to return to within 95% of its original height in not more than 30 mS.

3. Material according to Claim 2 wherein said recovery time can be maintained over a period of at least one hour during which the ridge is compressed at least once per second.

4. Material according to Claim 3 wherein the ridge is compressed at least 5 times per second.

5. Material according to any of the preceding claims wherein the material is sealed on at least each face by means of a continuous, integral skin or film.

6. Material according to any of the preceding claims wherein the material is latex-based having an ability to withstand a temperature of at least 160°C.

7. Material according to any of the preceding claims wherein said material is substantially flat on its other face.

8. Material according to any of the preceding claims wherein the maximum thickness of the material in an uncompressed condition is from 3 to 12 mm.

9. Material according to Claim 8 wherein said thickness is from 3.5 to 6 mm.

10. Material according to Claim 9 wherein said thickness from 3.5 to 4 mm.

11. Material according to any of the preceding claims wherein the cross-section area of each ridge is from 75 to 125%) of the cross-sectional area of each valley.

12. Material according to any of the preceding claims wherein the height of each ridge is at least 25% of the total thickness of the material.

13. Material according to any of the preceding claims wherein the height of each ridge is from 75 to 90%> of the total thickness of the material.

14. Material according to any of the preceding claims wherein the distance between the centre of a ridge and the centre of an adjacent valley is from 3 to 12 mm.

15. Material according to any of the preceding claims wherein the top of each ridge is substantially flat.

16. Material according to Claim 14 wherein the bottom of each valley has substantially the same width as the top of each ridge.

17. Material according to any of the preceding claims wherein the sides of each ridge converge in the direction towards the top of the ridge.

18. Material according to Claim 17 wherein the angle of convergence is from 0 to 15°.

19. Material according to any of the preceding claims wherein said material has bonded to a face thereof, which is remote from the or a shaped face, a fabrics support layer.

20. Material according to any of the preceding claims wherein said material has bonded to the or a shaped face thereof a water vapour permeable layer.

21. Material according to any of the preceding claims wherein said material has bonded to the or a shaped face thereof a pressure distributing layer.

22. Use of material according to any of the preceding claims in an item of clothing, the material having ridges and valleys on at least that face which, in use, is directed towards the wearer of the item of clothing.

23. Use according to Claim 22 wherein the item of clothing is an item of footwear, an item of headgear, a jacket or a coat.

24. An item of clothing incorporating material according to any of Claims 1 to 21.

25. An item of clothing according to Claim23 and wherein the material is arranged so that, during use, air movement along the valleys is effected.

26. Use of the material of any of Claims 1 to 21 as soundproofing or insulating material.

27. Soundproofing or insulating material incorporating material of any of Claims l to 21.