FR3121939A1 - Process for manufacturing an interior lining of a motor vehicle with improved performance - Google Patents

Abstract

A method of making an improved performance motor vehicle interior liner The method includes providing a web (20) of filaments (15), looping the filaments (15), accumulating the loops, depositing a reinforcing ply (38) on the accumulated loops, and the needling of the reinforcing ply and the loops to secure them. The sheet (20) provided is a nonwoven previously produced by extrusion of continuous filaments, the arrangement of the extruded filaments in at least a first layer, parallel to a first direction forming a predefined angle with a longitudinal direction, and the consolidation of the sheet (20) by leaving the filaments at least partially mobile relative to each other, and/or by bonding the filaments in a fusible manner to allow the looping of these filaments. Figure for the abstract: Figure 1

Description

Process for manufacturing an interior lining of a motor vehicle with improved performance

The present invention relates to a process for manufacturing an interior covering of a motor vehicle, in particular a floor covering.

More particularly, the invention relates to the manufacture of a thermoformable and needle-punched floor covering, of the velor type.

Devices for manufacturing interior linings for motor vehicles are already known in the state of the art, comprising in particular a needling machine of the DILOUR® type.

For example, document FR 3 041 001 describes a covering manufacturing device suitable for producing a homogeneous, high-density pile.

Such a device has the particularity of comprising conveyors covered with brushes which are used to form a homogeneous pile.

More particularly, the velvet is manufactured by implementing a preliminary step of producing a sheet of fibers elongated in a longitudinal direction, in particular by lapping with interlacing of the fibers, then a step of passing the sheet of fibers along the longitudinal direction, through a looping device comprising a set of rotating discs and fixed looping elements. The curling device curls the fibers by verticalizing them, thus forming undulations, then the sheet of fibers is brought on a conveyor equipped with brushes, so that the undulations accumulate in the brushes so as to reach a predetermined density.

In accordance with this known device, the structure constituted by the undulations of densified fibers is thus temporarily blocked inside the brushes of the conveyor of a Dilour machine, that is to say by a purely mechanical trapping and therefore without it is necessary to use a glue. This document then provides for the waves to penetrate deeper inside the brushes up to the depth corresponding to the height of the pile desired for the finished product.

The object of the present invention is in particular to improve such a manufacturing process, and in particular to improve its yield, while allowing the manufacture of a coating of quality at least equal, and generally superior, to that of the coating designed by the method known in the state of the art.

To this end, the subject of the invention is in particular a process for manufacturing a covering, in particular a floor covering for a motor vehicle, comprising:

- a step of supplying a sheet of filaments,

- a step of looping the filaments by means of a looping device comprising a set of rotating discs and fixed looping elements, the web having passed through the looping device in a direction of passage,

- a step of accumulation of the loops formed by the looping, in a conveyor equipped with brushes, arranged at the exit of the looping device,

- a step of depositing a reinforcing ply, formed of reinforcing fibers, on the loops accumulated in the brushes,

- a needling step for the reinforcement ply and the loops, in order to join them together,

characterized in that the web provided is a nonwoven previously produced during the following steps:

- a continuous filament extrusion step,

- a step of arranging the extruded filaments in at least a first layer, the filaments being arranged parallel to a first direction forming an angle with a longitudinal direction,

- A step of consolidating the web leaving the filaments at least partially mobile relative to each other, and / or binding the filaments in a fusible manner to allow the looping of these filaments.

The web according to the invention is of the type known according to the English terminology “spunbound”. Such a web of the “spunbound” type is generally produced according to two main steps, namely a step for producing filaments by extrusion, and a step for bonding or consolidating the filaments.

The sheet according to the invention is simpler and quicker to design than that of the state of the art, but still allows good implementation of the manufacturing process. As a result, the yield of the process is improved, without harming the quality of the coating produced.

It will be noted that the invention provides for moderate consolidation of the nonwoven sheet, such that the filaments remain at least partially mobile relative to each other, and/or bonded in a fusible manner. Indeed, the filaments do not have to be firmly bonded to each other in order to be crimped according to the manufacturing process.

A manufacturing method according to the invention may include one or more of the following characteristics, taken alone or in any technically possible combination.

- The production of the web comprises, following the arrangement step, a second step of extruding continuous filaments and a second step of arranging the filaments extruded during the second extrusion step into a second layer covering the first layer, the filaments of the second layer being arranged parallel to a second direction forming a second predefined angle with the longitudinal direction, the second angle being preferably opposite to the first angle.

- The filaments of the first layer have a first color, and the filaments of the second layer have a second color different from the first color.

- The filaments have a length greater than 20 cm, preferably greater than 50 cm.

- The filaments have a titer between 6.7 dtex and 17 dtex.

- The sheet has a surface mass of between 10 and 60 g/m².

- The undulations are formed by loops each having a predefined width G in a transverse direction perpendicular to the direction of passage, and a predefined height H in a direction of elevation perpendicular to the direction of passage and to the transverse direction, the filaments of the sheet being oriented parallel to a general direction forming an angle α with the direction of passage, given by the relation sinα=G/2H to within +/- 5°.

The invention also relates to a device for manufacturing a covering, in particular a floor covering for a motor vehicle, comprising:

- a device for producing a sheet of filaments,

- a device for looping the filaments comprising a set of rotating discs and fixed looping elements, and capable of receiving the sheet in a direction of passage,

- a conveyor equipped with brushes, arranged at the outlet of the looping device,

- a device for depositing a reinforcing layer on the loops accumulated in the brushes,

- a needling device for the reinforcement ply and the loops, in order to join them together,

characterized in that the production device is a device for producing a nonwoven, comprising:

- a continuous filament extrusion device,

- means for arranging the extruded filaments in at least a first layer, configured to arrange the extruded filaments parallel to a first direction forming a predefined angle with a longitudinal direction,

- a web consolidation device, configured to leave the filaments at least partially mobile relative to each other, and / or to bind the filaments in a fusible manner to allow the looping of these filaments.

A manufacturing device according to the invention may include one or more of the following characteristics, taken alone or in any technically possible combination.

- The looping device is capable of generating undulations formed by loops each having a predefined width G in a transverse direction perpendicular to the direction of passage, and a predefined height H in a direction of elevation perpendicular to the direction of passage and in the transverse direction, the arrangement means being configured to orient the filaments parallel to a general direction forming an angle α with the longitudinal direction, given by the relation sinα=G/2H to within +/- 5°.

- The sheet production device comprises a second device for extruding continuous filaments and second means for arranging the filaments extruded by the second extrusion device into a second layer covering the first layer, configured to arrange the filaments of the second layer parallel to a second direction forming a second predefined angle with the longitudinal direction, the second angle being preferably opposite to the first angle.

Different aspects and advantages of the invention will be highlighted in the following description, given solely by way of non-limiting example, and made with reference to the appended figures, among which:

- There schematically represents a device for manufacturing a coating making it possible to carry out the manufacturing method according to an exemplary embodiment of the invention;

- There is a partial cross-sectional view of a liner fabricated by the device for fabricating the ;

- There schematically represents in more detail a device for producing a web, integrated in the device for manufacturing the ;

- There is a schematic top view of a web produced by the device of the .

We have represented, on the , a device 10 for manufacturing a coating 12.

The coating 12, shown in more detail on the , for example forms an interior lining, and more particularly an interior lining of a motor vehicle, intended to cover the floor or a wall of the vehicle. Alternatively, liner 12 may form any conceivable interior liner.

The coating 12 has a face layer 14 of unbonded fibers parallel to each other, and a back layer 16 forming a sole formed essentially of fibers bonded together.

Face layer 14 has a velvety outer appearance. This pile consists of fibers in the form of sheared loops, as will be described later in more detail.

The thickness of the face layer 14 is generally greater than that of the sole 16. The face layer 14 has for example a thickness of between 2 and 8 mm.

The pile density in the face layer 14 is preferably between 0.05 and 0.12 g/cm3, for example between 0.07 and 0.08 g/cm3. Such a density ensures a good appearance, good resistance to abrasion and ease of cleaning.

This density is measured for example by determining the ratio between the mass of the material obtained by shaving the entire face layer 14 up to the sole 16, relative to the initial volume of the shaved layer.

The yield of the pile, consisting of the ratio of the weight of pile after total shaving up to the sole relative to the total weight of the part 12, is for example between 50 and 80%.

The manufacturing device 10 comprises a device 18 for producing a sheet 20 of nonwoven, shown in more detail on the .

The sheet production device 18 comprises for example an extruder 19 for manufacturing filaments. The filaments can be made of any suitable material, for example of thermoplastic material, in particular polyolefins, polyesters or polyamides.

In this case, the extruder 19 is shaped to melt the material, and conventionally includes a spinning nozzle to extrude the filaments.

In accordance with the invention, the extruder 19 is configured to produce filaments having a count of between 6.7 dtex and 17 dtex. Such filaments make it possible to optimize the implementation of the coating manufacturing process.

The filaments are continuous, and more particularly the filaments preferably have a length greater than 20 cm, advantageously greater than 50 cm.

The web-making device 18 then comprises means 21 for depositing the filaments on a conveyor belt 23 with a predefined deposition angle α, the deposition angle α being the angle formed between the deposited filament and a direction X d advancement of the conveyor belt 23. For example, the laying angle α is approximately equal to 20°.

The depositing means 21 comprise for example at least one guide plate 25 to orient the filaments. For this purpose, the filaments are deposited along this guide plate 25, which is oriented with respect to the conveyor belt 23 by forming said predefined laying angle α with this conveyor belt. The filaments thus deposited form a first layer.

Advantageously, the production of the web 20 provides for a second deposition of filaments on the previously deposited first layer, with an angle opposite to said predefined angle, to form a second layer superimposed on the first layer. More specifically, for a predefined angle α with the direction of the conveyor belt, the opposite angle is –α, as shown in Fig. .

To this end, the production device 18 comprises, for example, a second extruder 19' arranged downstream of the guide plate 25 along the conveyor belt 23, and second depositing means 21', comprising a second guide plate 25' downstream of the second extruder. The second guide plate 25' is oriented with respect to the conveyor belt 23 by forming said opposite angle -α with this conveyor belt 23.

Thus, as shown in the , the filaments of the first layer extend parallel to a first direction A forming the angle α with a longitudinal direction of the sheet 20 (corresponding to the direction of advance of the conveyor belt 23), and the filaments of the second layer extend parallel to a second direction B forming the angle -α with the longitudinal direction of the web.

According to an optional embodiment, the filaments of the second layer have a different color from that of the filaments of the first layer. This makes it possible to produce a coating with a two-tone aesthetic effect.

The sheet manufacturing device 18 also comprises means 27 for consolidating the structure formed by the first and second layers. These consolidation means 27 are for example consolidation means by needling, by water jets or by calendering.

It will be noted that, in the context of the invention, the consolidation is moderate, so that the filaments remain at least partially mobile relative to each other, or are bonded in a fusible manner to allow mobility of the filaments in the event of stress . For example, in order to obtain such a moderate consolidation, means of consolidation by calendering are used, by means of a calender whose temperature corresponds to the softening temperature of the polymer constituting the filaments. It will be recalled here that calendering consists of passing the sheet between two heated rollers.

In other words, the consolidation is carried out only to ensure structural consistency of the web 20 during its conveyance in the manufacturing device 10, without opposing the looping step which will be described later.

It should be noted that, for an optimal result, the sheet 20 has a basis weight of between 10 and 60 g/m².

A web 20 made as described above is also called “spunbound” in English terminology.

It should be noted that such a web of the spunbound type generally has a greater regularity than that of a web obtained by carding as is the case in the state of the art, in particular not having any density disparity.

The manufacturing device 10 comprises a looping device 28, arranged at the output of the device 18 for producing the sheet.

The sheet 20 is introduced into the looping device 28 in a direction of passage, which corresponds to the longitudinal direction of the sheet 20.

The looping device 28 is intended to loop the filaments 15 of the layer 20 by verticalizing them, thus forming undulations.

The looping device 28 comprises a set of rotating discs 30 carried on a common transverse axis, driven in continuous rotation at a peripheral speed preferably equal to the entry speed of the web 20.

The rotating discs 30 are preferably each provided on its periphery with a toothing allowing the sheet 20 to be driven.

The looping device 28 also comprises looping elements, in particular looping fingers 32, each being arranged between two adjacent discs 30 . The looper fingers 32 extend to one end which is substantially tangential to the discs 30. Thus, each filament 15 is pre-looped by being driven at each end by a respective disc 30, overcoming the looper finger 32 corresponding placed between these two discs 30.

The routing of a filament 15 between two adjacent discs 30 will now be described.

The filament 15 has an angle α with the longitudinal direction X, which is also the direction in which the sheet 20 passes through the looping device 28.

A front part of the filament is driven by one of the discs 30, and a rear part of this filament is driven by the other disc 30. These two discs being integral with the same axis, their speeds of rotation are identical.

The front part of the filament arrives first at the end of its travel, against an abutment which will be described later. While the front part is in abutment, the rear part continues to advance until it also comes into abutment, thus bending the filament which then forms a loop.

The filaments passing through the looping device 28 all have the same behavior as described above, so that all of the looped filaments form undulations over the width of the sheet 20, taken in a transverse direction perpendicular to the direction longitudinal X.

Each loop of the web 20 has a height H, taken in an elevation direction perpendicular to the longitudinal direction and to the transverse direction, and a width G taken in the transverse direction. It should be noted that the width G corresponds substantially to the interval between two adjacent discs 30.

The discs 30 are positioned in such a way that they penetrate from a depth P≤H inside the brushes of a band 33 of the same type as the brushes equipping the conveyor of a Dilour® machine. At the location of the disks 30, the bristles constituting the brushes are flexible enough to move apart and gather together in the free space between the disks.

This type of band serves as a stopper as mentioned above. Indeed, when they are no longer in the presence of the discs, the brush bristles, by returning to their initial position, exert pressure on the filaments which makes it possible to block and then maintain the structure of the undulations.

The abutment mentioned above is therefore formed by a belt 33 of a conveyor 34. The belt 33 is an endless belt, extending between two drive cylinders. Strip 33 is provided with brushes.

The strip 33 is moved, in the direction of passage, with a speed lower than the tangential speed of the rotating discs 30, so that they have the effect of a stop for the filaments emerging from these rotating discs 30.

The undulations then accumulate on the brushes of the strip 33, with a density depending on the difference in speed between the rotating discs 30 and the strip 33. Those skilled in the art will be able to determine this difference in speed as a function of the density desired.

This device makes it possible to obtain a high density of velvet.

The brushes also prevent the filaments from being dragged upwards by the discs 30, which would harm the formation of the waves.

The manufacturing device 10 then comprises a device 36 for depositing a reinforcing ply 38 on the corrugations accumulated on the brushes. The reinforcing ply 38 is formed by reinforcing fibers.

The reinforcing fibers are for example made from a thermoplastic polymer, such as polypropylene, polyethylene terephthalate (PET), polyamide, polylactic acid, their mixtures or their copolymers. As a variant, the reinforcing fibers can be fibers of natural origin such as flax or hemp fibers used alone or in mixtures.

The reinforcing fibers are for example of the same nature as the filaments 15.

However, in a variant, the reinforcing fibers are of a different nature from that of the filaments 15. They have, for example, a different titer, a different shine, and/or are made of different materials, or else may have a different color.

The reinforcing ply 38 can also be formed from a mixture comprising a percentage of binder fibers, that is to say, for example, bi-component fibers, one of the components of which has a lower melting point than the other.

It should be noted that the reinforcing ply 38 is preferably pre-needled. Thus, the reinforcing fibers are bonded together by this pre-needling operation.

Alternatively, the reinforcing ply 38 can itself be a “spunbond” type nonwoven, comprising two-component filaments, one of the components of which has a lower melting temperature than the other. In this case the reinforcing ply 38 has a traditional spunbond construction in which the filaments are distributed in all directions without presenting preferential orientations.

On the other hand, the method of bonding the filaments can be identical to that of the sheet 20 so as to ensure good mobility of the filaments relative to each other.

The structure formed by the stack of wavy filaments 15 and this reinforcing ply 38 is then intended to pass under a needling device 40 or needling head, comprising at least one needle board 41.

The assembly formed by the brush conveyor 34 and the needle boards is known per se, and for example formed by a machine of the Dilour® type.

The needle board 41 is arranged opposite the strip 33 of the conveyor 34, and it can be deployed vertically towards this strip 33 to pierce said structure.

The needle plate 41 carries a plurality of needles, the implantation of the needles of which complies with the Dilour® process and leads to homogeneous needling. Thus, this implantation can be arbitrary (known as “random” type) without in any way favoring a particular lineage.

This board of needles 41 makes it possible to secure the reinforcing ply 38 to the structure made up of superimposed undulations, by extracting reinforcing fibers from the ply 38 and causing them to penetrate into the ply 20.

The needling device is configured so that the depth of penetration of the reinforcing fibers of the reinforcing ply 38 into the ply 20 is sufficiently low so that the reinforcing fibers are not visible on the pile side after shearing. This height depends on the type of needles fitted to the needling head of the Dilour® machine, and the nature of the reinforcement ply 38.

During this needling, the face layer 14 is formed, as well as the sole 16.

The device 10 then comprises a device for bonding the filaments of the face layer 14 in the sole 16. This bonding device 42 is for example a heat-setting device, in particular a through-air oven or an infrared oven.

The bonding can be carried out in any conceivable way, for example by incorporating a latex into the reinforcing ply 38, or between the reinforcing ply 38 and the ply 20, or by incorporating thermofusible binder fibers among the filaments of the ply 20 and / or in the reinforcing ply 38. Binder fibers are generally preferred to latex, for reasons of recyclability.

This binding, necessary for all constructions of the needle-punched type to ensure sufficient cohesion of the fibers of the pile with the sole and to avoid problems of tearing or abrasion, is carried out in a conventional manner and will therefore not be described in more detail.

The device 10 then comprises a device 44 for shearing the top of the accumulated undulations of the structure, thus forming a pile of vertical fibers. Due to the verticalization of the undulations in the looping device 28 and the perfect parallelism of the resulting filaments, the shorn filaments all have the same height, so that the appearance of the pile is optimized. It should be noted that the shorn filament scraps can be subsequently recycled.

Finally, the device 10 comprises a device 46 for rolling up the coating 12 formed, with a view to handling it.

It should be noted that, so that the pile has an optimal appearance, in particular an optimal density, and that it does not have prematurely broken fibers in the looping discs, which would harm its general appearance, the angle α of orientation of the filaments 15 of the layer 20 must respect the relation sinα=G/2H to within +/- 5°.

The device according to the invention makes it possible to carry out a process for manufacturing a coating, which will now be described.

The manufacturing method includes a step of producing the web 20 of filaments. To this end, the method comprises a step of designing the filaments, for example by extrusion, followed by a step of depositing the filaments on the conveyor belt, oriented with the angle α with respect to the direction of advance of the conveyor belt, in a first layer. Preferably, the method then comprises a second step of depositing the filaments in a second layer superimposed on the first layer, the filaments of the second layer being oriented with the angle −α with respect to the direction of advance.

The method then includes a step of consolidating the web 20, so that the filaments remain at least partially mobile relative to each other, or are bonded in a fusible manner to allow mobility of the filaments.

The method then includes a step of passing the web 20 through the looping device 28, so as to generate undulations.

The manufacturing process then includes a step of bringing the sheet of fibers 20 onto the conveyor 34 equipped with brushes, and of accumulating the undulations in the brushes so as to reach a predetermined density. The conveyor 34 is arranged at the output of the discs 30, so that this feed step is carried out by the discs 30.

As mentioned earlier, the ripple density depends on the difference in speeds between the discs 30 and the belt 33.

It should be noted that the corrugated fibers thus accumulated are perfectly parallelized between them, so that the appearance of the coating 12 produced is optimal.

The method then includes a step of depositing the reinforcing ply 38, preferably pre-needled, on the accumulated corrugations. This reinforcement ply 38 is intended to form at least in part the sole 16.

The method then includes a step of needling the sheet of fibers 20 through the brushes of the strip 33, to form the structure comprising the face layer 14 and the sole 16, in accordance with a conventional needling process. Thanks to the needling step, the coating produced by the process according to the invention is thermoformable, therefore entirely suitable for the production of motor vehicle floor coverings.

The method then includes a step of removing the structure thus formed from the conveyor 34.

The method then includes a step of blocking or bonding the fibers of the face layer 14 in the sole 16. This blocking step is carried out in the blocking device 42, by any conceivable means.

The method then includes a step of mowing the top of the accumulated undulations of the structure.

The method finally comprises a step of rolling up the coating 12 thus formed, with a view to handling it.

It will be noted that the invention is not limited to the embodiments described above, and could present various variants.

In particular, the applications of this type of coating can extend to sectors other than the automotive industry, such as housing or rail transport, even in cases where formability is not required.

Claims (10)

Method of manufacturing a covering (12), in particular a floor covering for a motor vehicle, comprising:
- a step of supplying a layer (20) of filaments (15),
- a step of looping the filaments (15) by means of a looping device (28) comprising a set of rotating discs (30) and fixed looping elements (32), the web (20) being passed through the looping device in one direction of passage,
- a step of accumulating the loops formed by the looping, in a conveyor (34) equipped with brushes, arranged at the output of the looping device (28),
- a step of depositing a reinforcing ply (38), formed of reinforcing fibers (17), on the loops accumulated in the brushes,
- a step of needling the reinforcement ply (38) and the loops, in order to secure them,
characterized in that the web (20) provided is a nonwoven previously produced during the following steps:
- a continuous filament extrusion step,
- a step of arranging the extruded filaments in at least a first layer, the filaments being arranged parallel to a first direction (A) forming a predefined angle (α) with a longitudinal direction (X)
- a step of consolidating the web (20) leaving the filaments at least partially mobile relative to each other, and/or by binding the filaments in a fusible manner to allow the looping of these filaments. Manufacturing process according to claim 1, in which the production of the web (20) comprises, following the arrangement step, a second step of extruding continuous filaments and a second step of arranging the filaments extruded during the second step of extrusion in a second layer covering the first layer, the filaments of the second layer being arranged parallel to a second direction (B) forming a second predefined angle (-α) with the longitudinal direction, the second angle being preferably opposite the first angle. A manufacturing method according to claim 2, wherein the filaments of the first layer have a first color, and the filaments of the second layer have a second color different from the first color. Manufacturing process according to any one of the preceding claims, in which the filaments have a length greater than 20 cm, preferably greater than 50 cm. Manufacturing process according to any one of the preceding claims, in which the filaments have a count of between 6.7 dtex and 17 dtex. Manufacturing process according to any one of the preceding claims, in which the web (20) has a basis weight of between 10 and 60 g/m². Method of manufacture according to any one of the preceding claims, in which the undulations are formed by loops each having a predefined width G in a transverse direction perpendicular to the direction of passage, and a predefined height H in a direction of elevation perpendicular to the direction of passage and to the transverse direction, the filaments (15) of the ply (20) being oriented parallel to a general direction (A, B) forming an angle α with the direction of passage, given by the relation sinα= G/2H to within +/- 5°. Device (10) for manufacturing a covering (12), in particular a floor covering for a motor vehicle, comprising:
- a device (18) for producing a web (20) of filaments (15),
- a device (28) for looping the filaments (15) comprising a set of rotating discs (30) and fixed looping elements (32), and suitable for receiving the web (20) in a flow direction,
- a conveyor (34) equipped with brushes, arranged at the outlet of the looping device (28),
- a device for depositing a reinforcing ply (38) on loops accumulated in the brushes,
- a needling device for the reinforcing ply (38) and the loops, in order to secure them,
characterized in that the production device (18) is a device for producing a nonwoven, comprising:
- a device (19) for extruding continuous filaments,
- means (21) for arranging the extruded filaments in at least a first layer, configured to arrange the extruded filaments parallel to a first direction (A) forming a predefined angle (α) with a longitudinal direction (X)
- a device (27) for consolidating the sheet (20), configured to leave the filaments at least partially mobile relative to each other, and/or to bind the filaments in a fusible manner to allow the looping of these filaments. Manufacturing device according to claim 8, in which the looping device (28) is capable of generating undulations formed by loops each having a predefined width G in a transverse direction perpendicular to the direction of passage (X), and a height H predefined in an elevation direction perpendicular to the passage direction (X) and to the transverse direction, the arrangement means being configured to orient the filaments (15) parallel to a general direction (A, B) forming an angle α with the longitudinal direction, given by the relation sinα=G/2H to within +/- 5°. Manufacturing device according to claim 8 or 9, in which the device (18) for producing the web (20) comprises a second device (19') for extruding continuous filaments and second means (21') for arrangement of the filaments extruded by the second extrusion device (19) in a second layer covering the first layer, configured to arrange the filaments of the second layer parallel to a second direction (B) forming a second predefined angle (-α) with the longitudinal direction, the second angle preferably being opposite the first angle.