FR3140295A1 - Method of manufacturing a vehicle seat upholstery - Google Patents

Abstract

Method of manufacturing a trim (49) for a vehicle seat element, the method comprising the following steps: arranging a cap (40) in a mold (M) so that the cap (40) covers at least one part of the mold (M), overmolding, on said cap (40), a padding (41) comprising a 3D tangle of continuous thermoplastic fibers (52) arranged irregularly forming loops (43) welded together, said padding (41) being in the molten state, solidifying said padding (41) by cooling using a liquid (E) or a gas so as to secure said cap (40) and said padding together in order to obtain said padding ( 49). Abstract Figure: Figure 4

Description

Method of manufacturing a vehicle seat upholstery

The present description relates to a method of manufacturing a vehicle seat lining, in particular but not exclusively automobile, as well as a method of producing a vehicle seat element from a lining thus manufactured, as well as as a vehicle seat element produced using such a process.

The padding of vehicle seat elements, particularly automobiles, are conventionally made of urethane polymer foam (or polyurethane, PU), in particular polyurethane foam obtained from polyether/polyol (or PUR) type polyols. Such foams can be shaped in molds relatively easily, to form different shapes of padding for different vehicle seat elements, such as the seat or the backrest, for example.

Polyurethane foam padding is satisfactory, but can retain moisture, especially in humid conditions. This may cause a feeling of discomfort for an occupant of the vehicle seat, an element of which includes such padding.

In addition, polyurethane foam is conventionally made by mixing, among other things, polyols with isocyanates. The chemical reaction carried out emits CO ₂ to form a foam, the CO ₂ emitted contributing to global warming.

Furthermore, polyurethane foam is not recyclable.

Also, it appears desirable to limit the use of polyurethane in the padding of vehicle seat elements.

Furthermore, a vehicle seat comprises at least one frame, one padding and one cover, assembled with each other during assembly. There is a need to reduce the number of steps required for seat assembly.

Summary

This disclosure improves the situation.

1. disposer une coiffe dans un moule de manière à ce que la coiffe recouvre au moins une partie du moule,
2. surmouler, sur ladite coiffe, une matelassure comprenant un enchevêtrement 3D de fibres thermoplastiques continues disposées irrégulièrement formant des boucles soudées entre elles, ladite matelassure étant à l’état fondu,
3. solidifier ladite matelassure par refroidissement à l’aide d’un liquide ou d’un gaz de manière à solidariser ladite coiffe et ladite matelassure ensemble afin d’obtenir ladite garniture.

To this end, a process for manufacturing a trim for a vehicle seat element is described, the process comprising the following steps:

1. place a cap in a mold so that the cap covers at least part of the mold,
2. overmolding, on said cap, a padding comprising a 3D tangle of continuous thermoplastic fibers arranged irregularly forming loops welded together, said padding being in the molten state,
3. solidify said padding by cooling using a liquid or a gas so as to secure said cap and said padding together in order to obtain said padding.

Thus, the padding is made of a material other than polyurethane foam. This padding material is advantageously a recyclable plastic material and its production generates fewer CO ₂ emissions than the production of polyurethane foam. In addition, the process using this material for the padding can make it possible to produce a padding that is significantly lighter than a similar padding made of polyurethane foam. Additionally, the padding material may be more breathable, allowing air and possible moisture to pass better through the padding.

In addition, the process makes it possible to produce the filling during its implementation, by overmolding, including both the cover and the padding, which can simplify the assembly of the seat.

The trim includes the cover and the padding secured together.

The characteristics set out in the following paragraphs can, optionally, be implemented, independently of each other or in combination with each other.

The cap is preferably held against the part of the mold on which it is placed by suction of air, in particular throughout the implementation of steps A, B and C. A high vacuum is created in the mold so as to maintain the cap against the wall of the mold.

The cap is for example made of a material chosen from the group consisting of a woven material, a non-woven material, leather, artificial leather and imitation leather.

The mold can be in the form of a hollow shell whose walls reproduce the 3D configuration of the upholstery in its part visible to a user, once mounted on a seat frame.

1. extruder un matériau comprenant au moins un polymère thermoplastique dans une filière d’extrusion comprenant une pluralité de buses d’extrusion, pour former un rideau de fibres fondues ;
2. former, sur ladite coiffe, un enchevêtrement de fibres fondues, les fibres formant des boucles soudées entre elles.

Step B may include the following substeps:

1. extruding a material comprising at least one thermoplastic polymer into an extrusion die comprising a plurality of extrusion nozzles, to form a curtain of molten fibers;
2. form, on said cap, a tangle of molten fibers, the fibers forming loops welded together.

Step C is advantageously carried out concomitantly with step B, the solidification being implemented as the fibers are arranged on the cap.

Step C can be carried out by immersion in a cooling bath containing the liquid, in particular water. The initial temperature of the liquid is preferably between 8°C and 10°C. In one embodiment, the mold is movable relative to the cooling bath.

A step of cutting the tangle of fibers can be provided, particularly when the quantity of fibers is sufficient to produce the padding.

Preferably, the voids between the fibers of the 3D tangle of fibers of the padding are left free.

According to one embodiment of the method, the extrusion die implemented in sub-step i comprises, along the length direction of the extrusion die, several distinct zones comprising distinct surface densities of number of nozzles, comprising at least a first zone with a low surface density of number of nozzles, and at least a second zone with a high surface density of number of nozzles so as to obtain less than a first zone having a low apparent density and at least a second zone having a high apparent density, following the direction of the 3D tangle of fibers extending in the longitudinal direction of the extrusion die.

According to one embodiment, which can possibly be combined with the previous one, the extrusion die comprises, according to the width dimension of the extrusion die, a first section provided with first extrusion nozzles for the generation of hollow fibers, and a second section provided with second extrusion nozzles for the generation of solid fibers.

According to one embodiment, the temperature of the extrusion carried out in sub-step i in the extrusion die is between 180°C and 240°C.

The thermoplastic fibers of the padding may be hollow fibers and/or solid fibers, with a diameter of between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm. The composition of the fibers preferably comprises at least 95% by weight of PET. The thermoplastic material constituting the fibers can be recycled.

Sub-step ii may consist of guiding the curtain of molten fibers between two counter-rotating guide members by forming a congestion of fibers upstream of the two guide members, so as to form, on the cap, said tangle of molten fibers forming loops welded together.

The method may also include a step D consisting of thermoforming the padding after implementation of steps A, B and C, in particular by applying a thermoforming tool and heat, in particular hot air, to an exterior face of the padding located on the opposite side to an interior face of the padding which is in contact with the cap.

In one embodiment, the mold has a hollow shape with a bottom portion and at least two side portions that extend from the bottom. In this case, said cap covers all or part of the bottom part and the side parts and, during overmolding, the padding is bordered lower and laterally by the cap placed on the mold. Still in this case, thermoforming, when it takes place, aims to shape the part of the padding which is not in contact with the cover and can correspond to the outer face, upper in the mold, of the padding .

The process advantageously comprises a demolding step E.

A drying step, which may be brief, may be provided in the process, after thermoforming, if necessary, and before or after demolding for example, preferably after demolding.

The vehicle seat element may consist of at least one of:

- a file ;

- a seat ;

- an armrest;

- a headrest;

- a backrest top adjustment device; And

- a seat length adjustment device.

The vehicle seat element may in particular be a seat consisting of a backrest and a seat.

According to one embodiment, the thickness of the padding, when the seat element is a backrest, can be between 30 mm to 60 mm and/or the thickness of the padding when the seat element is a seat can be be between 40mm to 120mm.

According to one embodiment, the cushioning layer, when the seat element is a backrest, can comprise different zones having different apparent densities, distributed along the longitudinal direction of the cushioning layer, when the seat element is a backrest and/or the cushioning layer, when the seat element is a seat, may comprise different zones having different apparent densities, following the longitudinal direction of the cushioning layer.

The 3D tangle of the padding has, for example, an apparent density of between 45 kg/m ³ and 65 kg/m ³ .

• fournir une armature d’élément de siège de véhicule,
• réaliser une garniture pour élément de siège de véhicule en mettant en œuvre le procédé tel que défini ci-avant dans toutes ses combinaisons, et
• fixer la garniture sur l’armature d’élément de siège de véhicule.

According to another aspect, a method is proposed for producing a vehicle seat element comprising the steps consisting of:

• provide a vehicle seat element frame,
• produce a trim for a vehicle seat element by implementing the process as defined above in all its combinations, and
• attach the trim to the vehicle seat element frame.

According to another aspect, a vehicle seat element is proposed produced by implementing the method for producing a seat element as defined above in all its combinations.

Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

schematically represents a side view of an example of a vehicle seat.

shows schematically in sectional view a step of an example of a method according to the invention.

shows schematically in sectional view a step of an example of a method according to the invention.

shows schematically in sectional view a step of an example of a method according to the invention.

shows schematically in sectional view a step of an example of a method according to the invention.

shows schematically in sectional view a step of an example of a method according to the invention.

shows schematically in sectional view a step of an example of a method according to the invention.

shows schematically in perspective view an example of installation for the implementation of the stage of .

shows schematically and in section an example of a seat produced using the implementation of an example of a method according to the invention.

In the different figures, the same references designate identical or similar elements. For brevity, only the elements which are useful for understanding the embodiment described are represented in the figures and are described in detail below.

In the following description, when referring to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative, such as the terms “above”, “below”, “superior”, “lower”, etc., or to qualifiers of orientation, such as “horizontal”, “vertical”, etc., it is made reference, unless otherwise specified, to the orientation of the figures or of a vehicle seat in its normal position of use.

In particular, the longitudinal direction X means the longitudinal direction of the seat. The longitudinal direction of the seat is considered to be the same as the longitudinal direction of the motor vehicle in which the seat is mounted. This longitudinal direction X corresponds to the normal direction of travel of the vehicle. The longitudinal direction X is horizontal. The transverse direction Y of the seat thus corresponds to the transverse or lateral direction of the motor vehicle. This transverse direction corresponds to a direction perpendicular to the normal direction of movement of the vehicle. The transverse direction Y is horizontal. Finally, the vertical direction Z is a vertical direction of the seat, perpendicular to the longitudinal and transverse directions.

There schematically represents a motor vehicle seat 10 mounted on a slide mechanism 12.

The seat 10 comprises a seat 13, with a seat frame 14 and a seat pad 15, on which a backrest 16, with a backrest frame 17 and a backrest pad 18, is mounted. The backrest frame 17 here pivots around a transverse axis A, relative to the seat frame 14. To do this, an articulation mechanism 20 is arranged between the seat frame 14 and the backrest frame 17.

The seat 13 is mounted on movable profiles 22, also called slides or male profiles, via feet 24, 26. Each movable profile 22 is part of a slide 12 and is associated with a fixed profile 28. The fixed profile 28 is also called rail or female profile. The fixed profile 28 is fixed to the floor 30 of a motor vehicle.

The seat 10 comprises in this example a manual control element 32, called a rudder, for controlling the sliding of the slides 12. This manual control element 32 makes it possible in particular to block and unblock systems for stopping the sliding of the movable profiles 22 relative to each other. to the respective fixed profiles 28. Once the stopping systems have been unlocked, the manual control element 32 can also be used to slide the movable profiles 22 relative to their respective fixed profiles 28 of the slide 12 in the longitudinal direction X of the slides 12. The profiles fixed 28 and mobile 22 of the slides 12 are generally metallic. Alternatively, the movement of the movable profiles 22 relative to the fixed profiles 28 is controlled by means of an actuator.

According to the example illustrated, the seat 10 can also include a headrest 34. The headrest 34 can also include a headrest frame 35 and a headrest trim 36 fixed to the frame d headrest 35. The headrest frame 35 can in particular be fixed to the backrest frame 17 or mounted sliding in a substantially vertical direction relative to the backrest frame 17.

In the following, we describe in more detail an example of a method of producing a seat lining 15 which can be implemented in the seat 10 of the , knowing that a similar trim can be adapted to different vehicle seat elements. By “vehicle seat element”, we mean here one of:

- a seat 13;

- a folder 16;

- a headrest 34;

- an armrest;

- a backrest top adjustment device;

- a seat length adjustment device; And

- a set of at least two aforementioned elements.

In particular, the seat element may comprise a seat 13 and a backrest 16, the seat element then preferably consisting of a seat 13 and a backrest 16.

An example of a process for manufacturing a trim for a vehicle seat element is illustrated, step by step, in Figures 2 to 7.

The first step consists, in this example, of placing a cap 40 in a mold M so that the cap 40 covers at least part of the mold M. In this example the mold M has a hollow shape corresponding to the final shape exterior of the seat 13, with a bottom M1 integrating a substantially flat central part M2 surrounded by two hollow-formed lateral parts M3 and M3'. The M mold also has side uprights of which two side uprights M4 and M4’ are visible. The shape of the M mold is of course adapted to the shape of the seat element concerned.

The cover 40 constitutes the part visible to a user of the seat, the finishing cover of the seat. The headdress is for example made of woven, non-woven, leather, artificial leather or imitation leather.

As illustrated on the , in this example, the cap 40 is held against the part of the mold M on which it is arranged by suction of air using a suction system O represented by the arrows on the , through openings made in the mold M. The air suction is also represented schematically in Figures 4 and 5 described below illustrating stages during which the suction system O is still active and activated. work and making it possible to create a high depression in order to press the cap 40 against the mold M. Still in this example, as visible, the cap 40 completely covers the mold M, that is to say the bottom M1 and the lateral parts , including the visible lateral parts M4 and M4'. The suction system O is placed over the entire surface of the cap 40 placed on the mold M, as visible in Figures 3 to 5.

The second step illustrated on the consists of overmolding, on the cap 40, a padding 41 comprising a 3D tangle of continuous thermoplastic fibers 52 arranged irregularly forming loops welded together, as visible, the padding 41 then being in the molten state.

We represented on the an installation for overmolding the padding 20. The overmolding comprises a step consisting of extruding a plastic material containing at least one thermoplastic polymer, in an extrusion die 46 comprising a plurality of extrusion nozzles 48.

To do this, the extrusion die 46 can be supplied with polymer granules. The extrusion die 46 can for example be adapted to heat the plastic material, in particular the polymer granules, to a temperature between 180°C and 240°C.

According to the example illustrated, the extrusion nozzles 48 are regularly distributed in two perpendicular directions to form a matrix of extrusion nozzles 48. The extrusion die 46 thus makes it possible to form a curtain 50 of continuous, melted fibers 52, the density of fibers 52 of which is substantially constant in cross section (that is to say in a plane perpendicular to the direction of advancement of the extruded fibers 52). Here, the extrusion nozzles 48 are distributed in a horizontal plane. Also, to keep the density of the fibers 52 substantially constant in cross section of the curtain 50 of fibers 52, the fibers 52 are here driven by gravity at the outlet of the extrusion die 46.

By “curtain 50 of fibers 52”, we mean here a configuration of the fibers 52 extending substantially parallel to each other, the fibers 52 being included, in a plane perpendicular to their direction of advancement, in an envelope curve corresponding substantially to the section of the extrusion die 46, here substantially rectangular. Alternatively, we can speak of a rain of fibers 52 from the exit of the extrusion nozzles 48.

Preferably, at the outlet of the extrusion die 46, the temperature of the plastic material from which the fibers 52 are formed is between 180°C and 240°C.

The fibers 52, when they are deposited on the cap 40 in the mold M, tend to form continuous loops, which, due to the temperature of the fibers 52, weld together. In particular, the fibers 52 can fuse with each other. It is thus possible to obtain a tangle of melted fibers 52. The fibers 52 may be distributed irregularly in the tangle of fibers 52, in particular according to a distribution which may appear random to an observer.

The overmolding of the padding which has just been described makes it possible to obtain a substantially homogeneous padding 20, having similar fibers 52 and a homogeneous apparent density, throughout substantially the entire volume of the padding 20.

The third step, concomitant with the second step, that is to say carried out gradually, is also illustrated on the and consists of solidifying the padding 41 by cooling using a liquid or a gas, in this example a liquid E, more precisely water, so as to secure the cover 40 and the padding 41 together in order to to obtain the filling, as the fibers 52 are deposited in the mold M on the cap 40. This solidification step is carried out by immersion in a cooling bath containing the liquid E, in this example the water. The initial temperature of liquid E is between 8°C and 10°C. In this embodiment, the mold M is mobile relative to the cooling bath as illustrated in the with the two arrows F pointing downwards, which makes it possible to adjust the height of immersion of the mold M in the bath for this solidification step.

A step of cutting the tangle of fibers illustrated schematically by a pair of scissors C on the is provided, when the quantity of fibers 52 deposited in the cap 40 is sufficient for the production of the padding 41.

In this example, the voids 43 between the fibers 52 of the 3D tangle of fibers of the padding 41 are left free.

The method according to the illustrated embodiment subsequently comprises, as illustrated in the , a step consisting of thermoforming the padding 41 by applying, according to the arrows F1 downwards, a thermoforming tool T and hot air, through openings TO formed on the tool T, on an exterior face 44 of the padding 41 located on the side opposite to an interior face 45 of the padding 41 which is in contact with the cover 40.

Thermoforming aims to shape the part of the padding 41 which is not in contact with the cover 40 and corresponds to the outer face 44, upper in the mold M, of the padding 41.

The next step in the process consists of demoulding.

A drying step, which may be brief, may be provided in the process, after thermoforming, if necessary, and before or after demolding, preferably after demolding.

We obtain the finished and unmolded filling 49 illustrated on the . This is returned as illustrated in the , with the cover 40 in the upper part to be placed on the seat frame 14 in order to form the seat element, in this case the seat.

This process makes it possible, in one step, to manufacture the seat element lining including the quilting and the cover, or cover, without loss of manufacturing quality. The time required to produce the seat element is reduced. The quilting material makes the whole thing lighter and more breathable. The process is more ecological than in the prior art, saving approximately 50% of CO ₂ emissions and using recycled materials and generating subsequent recyclable waste.

In addition to the implementation of the overmolding described above, the installation of the provides control of the opening and closing of the extrusion nozzles 48. It is thus possible to open or close at least some of the extrusion nozzles 48 of the extrusion die 46 during the extrusion process. The opening and closing of the extrusion nozzles 48 can be controlled by an electronic control unit 70, in particular a computer.

The extrusion die 46 is shown here arranged vertically above the bath B of cooling liquid E, visible on the . The mold M is immersed in the bath B of coolant, the mold M being mobile in the bath B of coolant. The movement of the mold M can in particular be controlled by the electronic control unit 70. The mold M can in particular be moved vertically in the bath B, to control the height of the cavity 65 of the mold M immersed in the cooling bath B. Thus, the mold M is filled with the continuous molten fibers 52 so that loops are formed between the fibers 52. The fibers 52, immersed in the cooling bath, cool and harden, forming a tangle of continuous fibers, with loops. welded together.

The thermoplastic fibers of the padding in this example are hollow fibers and/or solid fibers, with a diameter of between 0.3 mm and 1.5 mm. The composition of the fibers comprises at least 95% by weight of PET. The 3D entanglement of the padding 41 has in this example an apparent density of between 45 kg/m ³ and 65 kg/m ³ .

We represented on the an example of a seat element constituted in this example by a seat 13 whose trim 49 was manufactured as described above then was fixed on the seat frame 14. The seat 13 was produced by providing the seat frame 14, then fixing on it a trim 49 obtained using the process described above. The thickness of the padding 41 is between 30mm and 120mm if we consider the seat or backrest. We do not depart from the scope of the invention if the seat element is a backrest, an armrest, a headrest or the like, or a combination of these.

The invention is of course not limited to the examples which have just been described.

In particular, the method may comprise the step of guiding the curtain of molten fibers between two counter-rotating guide members by forming a congestion of fibers upstream of the two guide members, so as to form, on the cap, said tangle of melted fibers forming loops welded together.

The thickness of the padding, when the seat element is a backrest, can be between 30 mm and 60 mm.

According to one embodiment, the cushioning layer, when the seat element is a backrest, can comprise different zones having different apparent densities, distributed along the longitudinal direction of the cushioning layer, when the seat element is a backrest and/or the cushioning layer, when the seat element is a seat, may comprise different zones having different apparent densities, following the longitudinal direction of the cushioning layer.

Claims (8)

Method of manufacturing a trim (49) for a vehicle seat element, the method comprising the following steps:

1. place a cap (40) in a mold (M) so that the cap (40) covers at least part of the mold (M),
2. overmolding, on said cap (40), a padding (41) comprising a 3D tangle of continuous thermoplastic fibers (52) arranged irregularly forming loops (43) welded together, said padding (41) being in the molten state,
3. solidify said padding (41) by cooling using a liquid (E) or a gas so as to secure said cap (40) and said padding together in order to obtain said padding (49).

Method according to claim 1, in which the cap (40) is held against said part of the mold (M) by suction of air, in particular throughout the implementation of steps A, B and C. Method according to one of the preceding claims, in which step C is carried out concomitantly with step B, the solidification being implemented as the fibers are arranged on the cap. Method according to any one of the preceding claims, in which step C is carried out by immersion in a cooling bath (B) containing said liquid (E), in particular water, the initial temperature of the liquid being preferably between 8°C and 10°C, the mold (M) preferably being mobile relative to the cooling bath (B). Method according to any one of the preceding claims, comprising a step D consisting of thermoforming the padding (41) after implementation of steps A, B and C, in particular by applying a thermoforming tool and heat, in particular hot air, on an exterior face (44) of the padding (41) located on the side opposite to an interior face (45) of the padding (41) which is in contact with the cover (40). Method according to any one of the preceding claims, comprising a demolding step E. Method according to any one of the preceding claims, step B comprising the following substeps:

1. extruding a material comprising at least one thermoplastic polymer into an extrusion die (46) comprising a plurality of extrusion nozzles (48), to form a curtain (50) of molten fibers (52);
2. forming, on said cap, a tangle of molten fibers (52), the fibers (52) forming loops (43) welded together.

Method for producing a vehicle seat element comprising the steps consisting of:

• provide a vehicle seat element frame,
• produce a trim (49) for a vehicle seat element by implementing the method according to any one of the preceding claims, and
• attach the trim (49) to the vehicle seat element frame.