GB2569151A

GB2569151A - Reformable article

Info

Publication number: GB2569151A
Application number: GB1720396.9A
Authority: GB
Inventors: Powell Richard; Powell Fiona
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2017-12-07
Filing date: 2017-12-07
Publication date: 2019-06-12
Anticipated expiration: 2037-12-07
Also published as: GB2569151B; GB201720396D0

Abstract

The thermoplastic layers 12 are preferably flush with the support layer 14 and may not extend more than 3 mm beyond it. The preferred support layer comprises woven glass or carbon fibres. The preferred thermoplastic layers comprise homopolymers or copolymers of methacrylates, ethylene, propylene or vinyl acetates, or polyamides. The preferred thermoplastics layers contain wax, fibres, fillers, antimicrobial agents, flame retardants, heat transfer agents and/or colourants. The article is preferably 1-4 (1-1.7) mm thick and thermoformable at 45-85 (60-65) °C. The preferred article comprises the laminate enveloped in porous neoprene (23, figure 8). The reformable article is part of a car seat.

Description

The present invention relates to a reformable article, and particularly but not exclusively to a reformable article comprising a thermoplastics material laminate. The present disclosure also relates to a seat for a vehicle and a vehicle including one or more such seats. Aspects of the invention relate to a reformable article, a seat for a vehicle, and a vehicle.

BACKGROUND

Vehicle seats, and particularly those in cars and especially in the front of cars, generally permit multiple adjustments to provide a comfortable ride for a driver or passenger. Due to the number of adjustments it is often difficult for the driver or passenger to obtain a wholly comfortable position.

As a result of the provision of such multiple adjustments, and the fittings required to provide these, and especially where these are provided by electric motors, vehicle seats tend in modern vehicles to be quite large and heavy. This leads to the seats being relatively expensive to produce, and also the addition to the vehicle’s overall weight of the relatively heavy seats affects the performance and fuel consumption of the vehicle.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a reformable article, a seat for a vehicle and a vehicle as claimed in the appended claims.

According to an aspect of the invention there is provided a reformable article, the article being in the form of a laminate comprising a support layer between two layers of thermoplastics material.

According to an aspect of the invention there is provided a reformable article, the article being in the form of a laminate comprising a support layer between two layers of thermoplastics material, wherein the thermoplastic layers extend beyond the edge of the support layer by no more than 3 mm.

This provides a reformable article which can be formed to a required profile on multiple occasions. The support layer adds strength and stiffness to the laminate.

The thermoplastics material layers may extend beyond the edge of the support layer by no more than 2 mm, and may extend beyond the edge of the support layer by no more than 1 mm. The edges of the thermoplastics material layers may be substantially flush with the edge of the support layer.

By limiting the amount by which the thermoplastics material layers protrude outside the edge of the support layer or by the thermoplastics layers being substantially flush with the edge of the support layer, creep of the thermoplastics material outside the original area of the article is mitigated or even prevented, and so dimensional stability of the article is achieved over repeated reforming operations.

The support layer may be fibrous.

The support layer may comprise any of carbon fibre or glass fibre.

The support layer may be in the form of a woven sheet.

This can provide for a relatively thin support layer, thereby providing a laminate of increased strength but reduced thickness relative to using thermoplastics material on its own.

The thermoplastics material may comprise any of methacrylates, polyamides, polyethylenes, polypropylenes, polyacetates, or copolymers thereof.

This permits appropriate thermoplastics material to be chosen for particular applications.

The thermoplastics material may comprise a mixture of a thermoplastic polymer and a wax. The wax may be any of an animal, vegetable or petroleum wax. The thermoplastics material comprises between 5 and 30 wt% wax.

The mixture of wax and thermoplastic polymer provides for a material which can be readily softened and hardened between rigid and formable states at appropriate temperatures.

The thermoplastics material may comprise an additive comprising one or more of fibres, fillers, antimicrobial materials, flame retardants, heat transfer agents or colourants.

This enables the thermoplastics material to have required properties for particular applications.

The thermoplastics material may have a forming temperature in the range 45 to 85°C, and may have a forming temperature in the range 50 to 70°C, and may have a forming temperature in the range 60 to 65°C.

This means that the reformable article can be formed at relatively low elevated temperatures, thereby avoiding the potential hazards of higher elevated temperatures.

Each thermoplastics material layer may have a thickness of between 1 and 4mm, and may have a thickness of between 1 and 1,7mm.

This provides for a relatively thin reformable article where the thermoplastics material is unlikely to creep due to large quantities of material at elevated temperatures during forming.

The support layer may be less than 1mm thick.

This enables a relatively thin reformable article to be produced, which will therefore require a relatively small energy input to fully heat up to a formable state.

The article may comprise an envelope in which the laminate is a snug fit so that the envelope supports the laminate. The envelope may be made of a porous material, and may be made of neoprene.

This enables the reformable article to retain its overall profile, and helps to prevent any creep of thermoplastics material.

According to another aspect of the invention, there is provided a reformable article for a vehicle seat, the article comprising a layer of thermoplastics material.

The article may comprise an envelope in which the layer is a snug fit so that the envelope supports the layer. The envelope may be made of a porous material. The envelope may be made of neoprene.

The reformable article may be in the form of a laminate which comprises a support layer between two layers of thermoplastics material. In such case an envelope as above may support the laminate. The support layer may comprise any of carbon fibre or glass fibre. The thermoplastics material may comprise any of methacrylates, polyamides, polyethylenes, polypropylenes, polyacetates, or co-polymers thereof.

A low friction coating may be provided on the outside of the reformable article.

The thermoplastics material may have a forming temperature in the range 50 to 70°C.

The article may have a thickness of between 1 and 1.7mm. The article may be less than 1mm thick.

According to an aspect of the invention, there is provided a device or item of furniture for supporting at least a portion of the weight of a user, the item comprising the reformable article as described in the preceding paragraphs.

The item may be one of a seat, a foot rest, a leg rest, and a bed. The item may be a device for a vehicle. The item may be a seat for a vehicle.

According to an aspect of the invention there is provided a seat for a vehicle comprising a body with a reformable support part in the body, the reformable support part comprising a reformable article as described in the preceding paragraphs.

According to another aspect of the invention there is provided a seat for a vehicle, the seat comprising a body with a reformable support part in the body, the reformable support part comprising a reformable article in the form of a laminate which comprises a support layer between two layers of thermoplastics material.

This provides for a vehicle seat which can be repeatedly formed to a required shape for a user of the seat. This enables the reformable support part to be formed to a required profile in situ in the seat, and hence with a person sitting thereon such that a required profile is achieved for a specific user.

The support layer may be fibrous.

The support layer may comprise any of carbon fibre or glass fibre.

The support layer may be in the form of a woven sheet.

The laminate may have a thickness of between 1 and 4mm, and may have a thickness of between 1 and 1.7mm.

The support layer may be less than 1mm thick.

This enables a relatively thin reformable support part to be produced, which will therefore require a relatively small energy input to fully heat up to a formable state.

The reformable support part may include heating means to heat the reformable article to above the forming temperature of the thermoplastics material to enable forming of the reformable article. The heating means may also be the heating means for controlling a user’s thermal comfort.

The reformable support part may comprise cooling means to facilitate cooling of the reformable article after forming thereof. The cooling means may also be the heating means for controlling a user’s thermal comfort.

This enables the reformable article to be cooled relatively rapidly following forming to a required profile using the heating means.

The reformable seat part may comprise a padded layer on the reformable article, and a padded layer may be provided on either side of the reformable article.

This provides for comfort for a user of the seat, and means that a user will not be sitting directly on the relatively rigid reformable article.

The padded layer may be porous to allow heat to pass therethrough.

This enables heat applied for instance when heating the reformable article to enable forming thereof, to be dissipated.

The seat may comprise a cover which is porous at least in areas corresponding to the location of the reformable article in the reformable support part in the body.

Again, this enables heat used for example to heat a reformable article, to be dissipated from the seat.

The seat may comprise a plurality of reformable support parts. The plurality of reformable support parts may have different rigidities to each other.

This enables different support to be provided for different parts of a user’s body. For instance, generally greater support would be required for the parts of a seat upon which a person actually sits down on.

The seat may comprise a reformable support part in the seat cushion of the seat base part of a seat upon which a user sits, and also a reformable support part in the squab of the seat arranged to support a user’s back.

A reformable support part may be provided in a front portion of the seat cushion of the seat, and a further reformable support part may be provided in a rear portion of the seat cushion of the seat.

A low friction coating may be provided on the outside of the or each reformable article. This coating could for instance be of silicone, and prevents the reformable article from sticking to surrounding components and materials such as the padded layer or layers, which otherwise and particularly during forming of the reformable article, could occur.

According to a still further aspect of the invention there is provided a vehicle in which the vehicle comprises one or more seats according to any of the preceding paragraphs.

The vehicle may comprise a reformable support part profiling control which is selectively actuable such that when actuated the control causes the reformable article to be heated to or above the forming temperature of the thermoplastics material, and this temperature to be retained for a required period of time such that a person sitting on the seat will cause the reformable article to be profiled to suit that person.

This enables the reformable support part to be profiled accurately to a particular user in situ.

The reformable support part profiling control may be configured to provide for cooling of the reformable support part subsequent to heating thereof.

This enables heat from the forming of the reformable support part to be dissipated once the forming has been concluded.

According to another aspect of the invention there is provided a method of adapting a seat of a vehicle according to the above paragraphs to improve user comfort, the method comprising: receiving a input indicating the reformable article should be reformed; activating a heating means to heat the article to or above the forming temperature of the thermoplastics material, and to maintain this temperature for a required period of time such that a person sitting on the seat will cause the reformable article to be reformed.

According to another aspect of the invention there is provided a method of adapting an item of furniture according to the above paragraphs to improve user comfort, the method comprising: receiving a input indicating the reformable article should be reformed; activating a heating means to heat the article to or above the forming temperature of the thermoplastics material, and to maintain this temperature for a required period of time such that a person sitting on the item will cause the reformable article to be reformed.

After activating a heating means the method may comprise activating a cooling means to cool the reformable article.

The input may be a user generated input from one of a vehicle HMI, a vehicle key fob, a switch, and a device HMI.

The input may be a signal from a sensor positively determining occupancy of the seat of the vehicle or item of furniture.

According to an aspect of the invention there may be provided a controller comprising means configured to perform the operations of the method of the above paragraphs.

According to another aspect of the invention there is provided a vehicle comprising the reformable article as described above, the seat as described above, or a controller for controlling a seat of a vehicle, as described above.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only with reference to the accompanying drawings, in which:

Fig. 1 is a diagrammatic perspective end view of an embodiment of the invention;

Fig. 2 is a diagrammatic perspective view of a further embodiment of the invention;

Fig. 3 is a diagrammatic more detailed sectional perspective view through part of the embodiment of Fig. 2;

Fig. 4 is a vehicle with an article of an embodiment of the invention and a controller of an embodiment of the invention;

Fig. 5 is a controller of an embodiment of the invention;

Fig. 6 is a method of an embodiment pf the invention;

Fig. 7 is a schematic sectional view of an article of an embodiment of the invention; and

Fig. 8 is a diagrammatic sectional perspective view through part of an embodiment of the invention.

Fig. 1 shows a reformable article 10 in the form of a laminate comprising a support layer 14 between two layers of thermoplastics material 12. In this instance the support layer 14 is a woven sheet of carbon fibre which is approximately 0.5mm thick. The thermoplastic layers 12 may be of a methacrylate such as PMMA. The layers 12 may be between around 0.5and 0.9mm thick, and may be approaching 0.85mm thick. The article 10 has an outer coating 16 of silicone.

The support layer 14 has a peripheral edge 15. The thermoplastic layers extend beyond the edge 15 of the support layer 14 by 1.5mm. The thermoplastic layers 12 overlap the edge 15 of the support layer 14 in the direction of the thickness of the support layer 14 to create an edge 11 of the laminate. In other embodiments, the thermoplastic layers 12 may extend up to 3mm beyond the edge of the support layer 14. In the embodiment shown in Figure 7 the edges 17 of the thermoplastic layers 12 are flush with the edge 15 of the support layer 14.

The article 10 may be formed in the following manner. A layer of carbon fibre woven sheet is laid between two layers of thermoplastics material. Silicone sheet layers are provided on the outside of the thermoplastics material layers and the laminate is formed in a heat press at temperatures of for instance between 100 and 120°C for a sufficient time for the thermoplastics material to melt and fully bond with the carbon fibre woven sheet.

Whilst the above materials and thicknesses have been indicated, these can be altered as required. For instance, a wide range of thermoplastics materials may be used other than methacrylates, such as for instance polyamides, polyethylenes, polypropylenes, polyacetates, or co-polymers of these. Rather than carbon fibre it may be possible to use glass fibre.

A wax may be provided in the thermoplastics material and for instance between 5 and 30wt% of wax could be provided, with the wax being any of an animal, vegetable or petroleum wax. The wax may provide for improved formability of the thermoplastics material when heated.

Other additives may be provided in the thermoplastics material including any of fibres, fillers, antimicrobial materials, flame retardants, heat transfer agents, colourants or others, to provide required properties for the thermoplastic layers.

The thermoplastics material including the wax and any other additives may have a forming temperature in the range 45 to 85°C, and more specifically may have a forming temperature in the range 60 to 65°C.

Figs. 2 to 4 show a device or item of furniture which is a vehicle seat 18 which in this instance comprises three reformable support parts 20, 22, 24 each including a reformable article 10 as described. As can be seen in Fig. 2 three reformable support parts 20, 22, 24 are provided, one part 20 at the lower end of a squab 25 of the seat arranged to support the base of a person’s back. A second part 22 is provided at a rear portion 27a of a seat cushion of the seat 18 upon which a person will sit. A third part 24 is provided at a front portion 27b of the seat cushion 27 of the seat 18.

Fig. 3 shows a part of the seat 18 including one of the support parts 20, 22, 24 in more detail. Here the reformable article 10 is provided immediately above a heater mat 28 as may be conventionally used in heated vehicle seats. The reformable article 10 and heating mat are sandwiched between two foam layers 30, 32 which provide padding. The foam layers 30, 32 are made of a porous material. On top of the top foam layer 30 a seat cover 34 is provided of any suitable material such as leather, textile etc. The seat cover 34 is porous at least to the extent of the parts which overlie the reformable article 10. As is conventional a PELTIER heater/cooler 36 is provided beneath the lower foam layer 32 and a fan may be provided for blowing cold air from the heater/cooler 36.

The reformable support part 22 at the rear portion of the base of the seat 18 may be more rigid than the other support parts 20, 24, as the part 22 bears more weight. The variable rigidities may be provided by using different materials, different grades of material, different additives in the material and/or different thicknesses of material as appropriate in the reformable article 10.

In an alternative embodiment, as shown in Figure 8, an item of furniture 19 may comprise all the features of the embodiment of Figures 2 to 4, and use the same reference numbers for equivalent features, except the reformable article 21 may comprise a single thermoplastic layer 12, without a support layer. An envelope 23 may be provided around the article for support. The envelope 23 may be porous, and may be neoprene. The item of furniture 19 may have a cover 39.

Figure 4 illustrates an example of a vehicle 40 comprising one or more seats 18. A control means 42 is configured to control forming of the reformable article 10. In use when it is required for the profile of the seat 18 to be adjusted, for example when the vehicle is new, or is being used for the first time by a driver or passenger, or if it is desired to have additional comfort, the control means 42 is arranged to receive an input 43 indicating that the article 10 should be reformed. Upon receipt of the input 43, the control means 42 is configured to, in the illustrated example, activate a heating means, for example the heater mat 28, to heat the reformable article 10 to or above the forming temperature of the thermoplastics material.

The reformable article 10 may then be formed by the weight of a person sitting on the seat 18 to the profile of the person, and hence provide optimum comfort. Limiting the overlap of the the thermoplastic layers 12 beyond the support layer 14 mitigates creep of the thermoplastic material beyond the edge of the support layer so that the article is dimensionally stable. The control means 42 may be configured to activate the heater mat 28 for a required time, following receipt of the input 43. Additionally/alternatively the control means 42 may be configured to respond to a user input to activate/deactivate the heater mat 28. Subsequent to the heating of the reformable article 10, cooled air from the heater/cooler 36 may be blown through the foam layers 30, 32 and thus over the reformable article 10, out through the openings in the seat cover 34, to dissipate heat in the seat 18.

Figure 5 illustrates a simplified block diagram of an example embodiment of the control means 43 for controlling forming of the reformable article 10. In the illustrated embodiment, the control means 43 comprises a controller 50. The controller 50 illustrated in Figure 5 comprises a programmable module, for example comprising one or more processors arranged to execute computer program code 52 stored within one or more memory elements 51. The, or each, memory element 51 comprises a non-transitory computer-readable medium, and may be in the form of one or more of random access memory (RAM), readonly memory (ROM), programmable ROM (PROM) such as erasable programmable ROM (EPROM), a magnetic data storage medium, an optical data storage medium, Flash memory, etc.

In alternative embodiments, the controller 42 may be implemented, wholly or partly, by way of non-programmable circuitry, for example in the form of an application specific integrated circuit (ASIC) device, Boolean logic circuitry, etc.

The controller 50 is coupled (directly or indirectly) to one or more input devices 53 and arranged to receive one or more input signals 54 from the input devices 53. The input device(s) 53 may comprise, for example, a vehicle HMI (Human Machine Interface), a vehicle key fob, one or more switches, a remote device HMI such as a mobile device app, occupancy detection sensors, or the like. The controller 50 may also be coupled to one or more output devices 55, for example a display, to allow the controller to output information etc. to a user.

In the embodiment illustrated in Figure 5, the controller 50 is arranged to output control signals 57, 58 to the heater mat 28 and PELTIER heater/cooler 36 respectively to enable the controller 50 to activate/deactivate the heater mat 28 and PELTIER heater/cooler 36 respectively.

Referring now to Figure 6, there is illustrated a simplified flowchart of an example of a method of adapting a seat of a vehicle, such as may be implemented by the controller 50 of Figure 5 to adapt the seat 18 of the vehicle 40. The method of Figure 6 starts at 605 with the receipt of an input 43 indicating that the reformable article 10 should be reformed. Such an input 43 may comprise a user generated input from one of a vehicle HMI, a vehicle key fob, a switch, a remote device HMI, or a signal from an occupancy detection system sensor positively determining occupancy of the seat of the vehicle.

Upon receipt of the input 43 indicating the reformable article 10 should be reformed, the method moves on to 615 where a heating means, for example the heating mat 28, is activated to heat the article 10 to or above the forming temperature of the thermoplastics material. In the embodiment of Figure 6, a timer 59 (Figure 5) is then initialized at 620 and the method waits until the timer expires, at 630, at which point the method moves on to 635 where the heating means is deactivated. In this manner, the article 10 may be maintained at or above the forming temperature of the thermoplastics material for a period of time such that a person sitting on the seat 18 will cause the reformable article 10 to be profiled to suit that person.

In some embodiments, such as that illustrated in Figure 6, the method may exit from its heating state prior to the expiry of the timer 59 upon receipt of a stop signal, at 625. Such a stop signal may be received from a user input device and initiated by a user.

Having deactivated the heating means at 635, the method moves on to 640 where a cooling means, for example the PELTIER heater/cooler 36 is activated to cool the reformable article 10 after it has been heated. In the embodiment of Figure 6, a timer (e.g. timer 59 again) is then initialized at 645 and the method waits until the timer expires, at 650, at which point the method moves on to 655 where the cooling means is deactivated, and the method ends at 660.

There is thus described an embodiment of the invention wherein a vehicle seat is provided, the profile of which can provide for specific adjustment to any user as required. Using the described reformable article means that it is not necessary to provide the usual adjustment fittings in the seat.

The structure of the reformable article provides for a repeatably reformable part, where the support layer provides support for the thermoplastics material, meaning that a relatively thin laminate can be used. The thinness of the laminate reduces the weight thereof, and also the amount of heat needed to heat the thermoplastics material so as to be formable. This therefore means that the reformable support part can be heated up relatively rapidly and therefore reformed relatively rapidly, with relatively quick cooling thereof thereafter.

Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. For example, the reformable support parts may be provided in different parts of the seat, and a different number of parts may be provided as required. Different arrangements may be provided for heating and/or cooling the reformable support parts. It may be appropriate or required to provide a frame or envelope or sleeve which locates around the reformable support part to maintain the overall dimensions and shape thereof. In particular, the reformable article may comprise such an envelope in which the article is a snug fit so that the envelope supports the article. This envelope may be porous and may be made of neoprene.

The skilled person will understand that, although the above embodiment relates to a vehicle seat, the reformable article could be added to other devices that support the weight of a user, to improve comfort by allowing the support of the device to be adapted specifically for the user. For example, a reformable article could be added to a leg rest, a foot rest, a head rest, a bed or other item of furniture. The skilled person would understand in such examples, that references to the reformable article 10 being formed by the weight of a person sitting on the seat could be considered as references to an article being formed by the weight of a person’s leg, foot, head, or body, respectively.

In an alternative embodiment, as shown in Figure 8, an item of furniture, which may be one of a seat, a leg rest, a foot rest, a head rest, and a bed, may comprise a reformable article which comprises a single thermoplastic layer 12, without a support layer. An envelope 23 may be provided around the article for support. The envelope 23 may be porous, and may be neoprene.

Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A reformable article, the article being in the form of a laminate comprising a support layer between two layers of thermoplastics material, wherein the thermoplastic layers extend beyond the edge of the support layer by no more than 3 mm.

2. A reformable article according to claim 1, wherein the thermoplastics material layers extend beyond the edge of the support layer by no more than 2 mm.

3. A reformable article according to claim 2, wherein the thermoplastics material layers extend beyond the edge of the support layer by no more than 1 mm.

4. A reformable article according to claim 3, wherein the edges of the thermoplastics material layers are substantially flush with the edge of the support layer.

5. A reformable article according to any preceding claim, in which the support layer is fibrous.

6. A reformable article according to claim 5, in which the support layer comprises any of carbon fibre or glass fibre.

7. A reformable article according to claim 5 or claim 6, in which the support layer is in the form of a woven sheet.

8. A reformable article according to any of the preceding claims, in which the thermoplastics material comprises any of methacrylates, polyamides, polyethylenes, polypropylenes, polyacetates, or copolymers thereof.

9. A reformable article according to any of the preceding claims, in which the thermoplastics material comprises a mixture of a thermoplastic polymer and a wax.

10. A reformable article according to claim 9 in which the wax is any of an animal, vegetable or petroleum wax.

11. A reformable article according to claims 9 or 10, in which the thermoplastics material includes between 5 and 30wt% wax.

12. A reformable article according to any of the preceding claims in which the thermoplastics material includes an additive comprising one or more of fibres, fillers, antimicrobial materials, flame retardants, heat transfer agents or colourants.

13. A reformable article according to any of the preceding claims, in which the thermoplastics material has a forming temperature in the range 45 to 85°C.

14. A reformable article according to claim 13, in which the thermoplastics material has a forming temperature in the range 50 to 70°C.

15. A reformable article according to claim 14, in which the thermoplastics material has a forming temperature in the range 60 to 65°C.

16. A reformable article according to any of the preceding claims, in which the article has a thickness of between 1 and 4mm.

17. A reformable article according to claim 13, in which the article has a thickness of between 1 and 1.7mm.

18. A reformable article according to any of the preceding claims, in which the support layer is less than 1mm thick.

19. A reformable article according to any of the preceding claims, in which the article includes an envelope in which the laminate is a snug fit so that the envelope supports the laminate.

20. A reformable article according to claim 19, in which the envelope is made of a porous material.

21. A reformable article according to claim 19 or claim 20, in which the envelope is made of neoprene.