Seat padding containing fiber beads

Abstract

The present invention relates to a seat cushion comprising fiber beads. Abstract figure: Figure 2

Description

Title of the invention: Seat padding comprising fiber beads technical field

[0001] This disclosure falls within the field of safe mattresses for seating elements, in particular automotive seating. Previous technique

[0002] Seat cushions, particularly for car seats, are typically made of polyurethane foam. Indeed, it is easy to produce a polyurethane foam that has the desired properties, especially density and hardness, for use as cushioning.

[0003] The synthesis of polyurethane foams is based on the polyaddition reaction between a polyol and a polyisocyanate compound. Polyols and polyisocyanate compounds are petrochemical-derived polymers whose production generates significant quantities of CO2.

[0004] In order to reduce dependence on oil, and also decrease the amount of CO2 emitted, it is therefore necessary to find an alternative to polyurethane foam. Summary

[0005] A padding for a seat element is proposed, in particular for an automobile seat element, for an aircraft seat element, for a furniture seat element, especially for an automobile seat element, comprising fiber beads, in which each fiber bead: - has a diameter between 1 mm and 30 mm, particularly between 2 mm and 20 mm, and especially between 4 mm and 10 mm, and - includes matrix fibers and bicomponent fibers.

[0006] Advantageously, the process for producing matrix fibers and two-component fibers from fiber beads can be less energy-intensive and more economical than the process for producing polyurethane foams. Fibers, such as polyester fibers, polyamide fibers, or polypropylene fibers, can also be obtained from recycled sources.

[0007] In addition, the seat element padding of the present invention is easily recyclable, whereas conventional padding made of polyurethane foam is difficult to recycle.

[0008] The comfort level of a mattress is determined, in particular, by its density and Its hardness. Although the padding of the present invention offers the same level of comfort as conventional padding made of polyurethane foam, the padding of the present invention is advantageously lighter and more breathable than conventional padding made of polyurethane foam. This is very advantageous for reducing the weight of automobiles. Without wishing to be bound by any theory, the inventors are of the opinion that the advantageous mechanical properties of the padding of the present invention are obtained thanks to the fiber balls. Indeed, the diameter of the fiber beads allows for easy and even filling of the mattress production mold, resulting in a mattress with uniform density and hardness. The 3D morphology and flexibility of the fiber beads give the mattress its resilience under compression, its lightness, and its breathable appearance.

[0009] According to another aspect, a method for producing a mattress as defined above is proposed, the method comprising the following steps: a) mixing of matrix fibers and bicomponent fibers to obtain a fiber mixture, b) production of fibre balls from the fibre mixture, and c) production by molding of the mattress from the fiber balls.

[0010] This process is advantageously easy to implement, economical and energy-efficient. Brief description of the drawings

[0011] Other features, details and advantages will become apparent from reading the detailed description below and from analyzing the accompanying drawings, in which: Fig. 1

[0012] [Fig. 1] is a photograph of a fiber bead according to the invention Fig. 2

[0013] [Fig.2] is a photo of a quilting according to the invention. Description of the implementation methods

[0014] According to one aspect, a padding for a seat element is proposed, in particular for an automobile seat element, for an aircraft seat element, for a furniture seat element, especially for an automobile seat element, comprising fiber beads, in which each fiber bead: - has a diameter between 1 mm and 30 mm, particularly between 2 mm and 20 mm, and especially between 4 mm and 10 mm, and - includes matrix fibers and bicomponent fibers.

[0015] For the purposes of the present invention, the expression "padding for seat element" refers to the element of the upholstery of a seat element which is covered with a cover.

[0016] For the purposes of the present invention, "seat element" means a headrest, an armrest, a backrest, a cushion and combinations thereof.

[0017] For the purposes of the present invention, the term "fiber balls" refers to a mixture of fibers having a spherical shape. The cohesion and mechanical properties of the fiber balls are ensured by the matrix fibers bonded together by means of the two-component fibers.

[0018] For the purposes of the present invention, the term "matrix fibers" refers to polymeric fibers.

[0019] For the purposes of the present invention, the term "bicomponent fibers" refers to fibers composed of two distinct polymers distributed along the entire length of the fibers. The morphology of the cross-section of the bicomponent fibers may be side-by-side, core / mantle, segmented, island-in-the-sea, or combinations thereof, particularly side-by-side, core / mantle, or combinations thereof, especially core / mantle.

[0020] Seat padding, particularly automotive seat padding, must have certain mechanical properties to ensure seat comfort. Specifically, these mechanical properties, such as the density and / or hardness of the padding, must offer a satisfactory compromise so that the padding is neither too firm nor too soft.

[0021] Thus, the padding for a seat element may have at least one, in particular the following two mechanical properties: a density between 30 kg / m3 and 80 kg / m3, in particular between 40 kg / m3 and 70 kg / m3, especially between 50 kg / m3 and 65 kg / m3, a hardness, for a measurement at 40% compression, of between 3 kPa and 16 kPa.

[0022] The hardness of the padding may depend on the seat element. Typically, the hardness, for a measurement at 40% compression, of padding: - the central part of the seat back is between 4.5 kPa and 6 kPa, - the central part of a seat cushion has a pressure between 6.5 kPa and 9 kPa, - the side of the seat back is between 10 kPa and 14 kPa, - the side of the seat cushion is between 9 kPa and 12 kPa, - of a headrest is between 6 kPa and 8 kPa.

[0023] Advantageously, the seat element padding having at least one, at least two, more particularly these three mechanical properties is as comfortable as a conventional polyurethane foam padding.

[0024] Matrix fibers can be chosen from fibers of the polyester family, fibers of the polyamide family, fibers of the poly- family propylenes and their mixtures, in particular among the fibers of the polyester family, the fibers of the polyamide family and their mixtures, especially among the fibers of the polyester family.

[0025] Typically, matrix fibers may exhibit: - a length between 5 mm and 150 mm, in particular between 20 mm and 100 mm, especially between 30 mm and 70 mm, and / or a titration between 2 dtex and 60 dtex, in particular between 4 dtex and 40 dtex, especially between 6 dtex and 20 dtex.

[0026] Matrix fibers with a length and / or count exceeding the ranges indicated above are not suitable for forming fiber beads. Mattress comprising fiber beads obtained from matrix fibers with a length and / or count below the ranges indicated above does not exhibit the mechanical properties for use in a seat.

[0027] Typically, the two polymers in two-component fibers can have different melting points. One of the two polymers therefore has a melting point, Tfusion1, lower than the melting point, Tfusion2, of the other polymer. Tfusion1 is therefore lower than Tfusion2*

[0028] Advantageously, such two-component fibers strengthen the cohesion of the padding and increase its hardness. In particular, the polymer with a melting point of Tfusioni affects the cohesion of the padding by bonding the matrix fibers together and the fiber beads together through thermal consolidation.

[0029] The polymer of the two-component fibers whose melting point is Tfusioni can be chosen from the family of polyesters, the family of polyamides, the family of polypropylenes and their mixtures, in particular from the family of polyesters, the family of polyamides and their mixtures, especially from the family of polyesters.

[0030] The polymer of the two-component fibers whose melting point is Tfusion2 can be chosen, independently of the polymer whose melting point is Tfusioni, from the family of polyesters, the family of polyamides, the family of polypropylenes and their mixtures, in particular from the family of polyesters, the family of polyamides and their mixtures, especially from the family of polyesters.

[0031] According to a particular embodiment, the two-component fibers may have a core / coat morphology and the coat polymer has the melting point Tfusion1 and the core polymer has the melting point Tfusion2. Advantageously, this particular embodiment strengthens the cohesion of the padding and increases the hardness of the padding.

[0032] According to a very particular embodiment: - the core polymer can be chosen from the polyester family, the family of polyamides, the polypropylene family and their blends, particularly within the polyester family, and - the coating polymer can be chosen, independently of the core polymer, from the polyester family, the polyamide family, the polypropylene family and their mixtures, in particular from the polyester family, the polyamide family and their mixtures, especially from the polyester family.

[0033] Typically, bicomponent fibers may exhibit: - a length between 5 mm and 150 mm, in particular between 20 mm and 100 mm, especially between 30 mm and 70 mm, and / or a titration between 2 dtex and 60 dtex, in particular between 4 dtex and 40 dtex, especially between 6 dtex and 20 dtex.

[0034] Bicomponent fibers with a length and / or fiber content exceeding the ranges indicated above may not be suitable for forming fiber balls. Padding made from fiber balls obtained from bicomponent fibers with a length and / or fiber content below the ranges indicated above may not possess the mechanical properties required for use in a seat.

[0035] The mass ratio of matrix fibers to bicomponent fibers of each fiber bead of the padding according to the invention can be between 1:0.05 and 1:2.5, in particular between 1:0.1 and 1:1, especially between 1:0.15 and 1:0.7. The mass ratio of matrix fibers to bicomponent fibers of each fiber bead of the padding according to the invention can alternatively be between 1:0.1 and 1:3.

[0036] Advantageously, a mass ratio within the ranges described above is suitable for obtaining the advantageous mechanical properties of the padding according to the invention.

[0037] According to another aspect, a method for producing a mattress according to the invention as described above is proposed, the method comprising the following steps: a) mixing of matrix fibers and bicomponent fibers to obtain a fiber mixture, b) production of fibre balls from the fibre mixture, and c) production by molding of the mattress from the fiber balls.

[0038] Matrix fibers, bicomponent fibers and fiber balls are as described above in connection with the padding according to the invention.

[0039] Advantageously, the process of the invention is simple for a person skilled in the art to implement. Indeed, steps a) and b) are conventional steps known to The man in the trade.

[0040] Step a) can be implemented by a fiber mixing machine and step b) can be implemented by a rotating machine.

[0041] Typically, step c) can be carried out according to the following substeps: c1) incorporation of the fiber beads into a mold, c2) closing of the mold, then c3) injection of hot air into the mold.

[0042] The mold of step cl) can have a shape adapted to the seat element, in particular car seat, airplane seat, furniture seat, especially car seat.

[0043] Step c) can alternatively be carried out in a mold that does not have a suitable shape for the seat element, in particular for an automobile seat, an aircraft seat, or a seat for furniture, especially an automobile seat. In this case, the padding produced at the end of step c) can then be shaped to have the desired form.

[0044] During step c2), the mold is closed to make it airtight and the fiber beads enclosed in the mold can be slightly compressed. This optimizes the effects of step c3).

[0045] During step c3), the hot air temperature is greater than the melting point, Tfusion i, of the polymer of the bicomponent fibers whose melting point is Tfusion b in particular greater than the melting point of the polymer of the coat of the bicomponent fibers having a core / coat morphology.

[0046] Advantageously, this allows the polymer of the two-component fibers whose melting point is Tfusioni to be activated and then, after cooling, the matrix fibers to be linked together and the fiber beads to each other in the padding.

[0047] The melting point of polymers is common or easily determinable data for a person skilled in the art. They will therefore know how to determine the temperature of the hot air used in step c3).

[0048] For example, the temperature of the hot air can be between 80°C and 220°C. Such a temperature range is suitable for polyester, polyamide, and polypropylene as polymers of two-component fibers whose melting point is Tmelting.

[0049] The process may further include, between step a) and step b) one or more steps of working the fiber mixture to obtain a homogenized fiber mixture, said homogenized fiber mixture then being implemented in production step b).

[0050] The processing step(s) allow the fibers to be stretched and aligned to homogenize the fiber mixture, which can be advantageous. Examples

[0051] Example 1: padding for car seat headrest.

[0052] The matrix fibers are polyester fibers with a density of 4 dtex and a length of 51 mm. The two-component fibers have a core / cladding morphology. The cladding polymer is a polyester with a melting point Tfusion1 of 110°C. The core polymer is a polyester with a melting point Tfusion2 greater than 110°C. The two-component fibers have a density of 7 dtex and a length of 65 mm.

[0053] The fibers are mixed so that the mass ratio of matrix fibers to two-component fibers is 1:0.43. The mixture then undergoes a processing step to obtain a homogenized mixture. This homogenized mixture is then passed through a fiber bead forming machine to form fiber beads with a diameter between 4 mm and 9 mm. Figure 1 shows one of these fiber beads.

[0054] The fiber balls are then placed in a machine that propels them into a mold for forming the padding of an automotive seat headrest. This mold is filled with fiber balls in the quantity necessary to obtain padding with a density of 53 kg / m³. The mold is then closed to form the padding. Hot air, i.e., with a temperature between 110°C and 150°C, is injected into the mold to activate the bicomponent fibers. The injection time is in accordance with the recommendations of the bicomponent fiber supplier. The mold is then cooled to return to ambient temperature. The padding is then demolded. Figure 2 shows this padding.

[0055] The density of the padding is measured by the method described in the DIN EN ISO 845 standard of July 15, 2014. Hardness is measured, at 40% compression, by the destructive method described in DIN EN ISO 3386-1 of August 8, 2019.

[0056] Some physico-chemical characteristics of the padding, including density and hardness, are presented in Table 1 below.

[0057] Examples 2 to 4: different padding for an automotive seat element

[0058] The padding in Examples 2 to 4 is obtained according to the process of Example 1. The differences are shown in Table 1 below.

[0059] [Tables 1] Example 1, headrest Example 2, headrest Example 3, central backrest Example 4, central backrest Matrix fiber count: 4 dtex 4 dtex 7 dtex 17 dtex Matrix fiber length: 51 mm 51 mm 50 mm 60 mm Bicomponent fiber count: 7 dtex 7 dtex 7 dtex 7 dtex Bicomponent fiber length: 65 mm 65 mm 50 mm 50 mm Fiber bead diameter: 4 mm - 9 mm 4 mm - 9 mm 5 mm - 8 mm 5 mm - 8 mm Mattress density: 53 kg / m³ 60 kg / m³ 50 kg / m³ 60 kg / m³ Mattress hardness: 7.7 kPa 8 kPa 8 kPa 9 kPa

Claims

Demands

1. Molded padding for a seat element comprising fiber beads, in which each fiber bead: - has a diameter between 1 mm and 30 mm, and - comprises matrix fibers and bicomponent fibers, the padding being characterized in that: - it has a density between 50 kg / m3 and 65 kg / m3 and a hardness, for a measurement at 40% compression, between 3 kPa and 16 kPa, - the bicomponent fibers have a length between 5 mm and 150 mm and a count between 6 dtex and 20 dtex, - the bicomponent fibers are composed of two polymers and one of the two polymers has a melting point, Tfusion1, lower than the melting point, Tfusion2, of the other polymer, - the polymer whose melting point is Tfusion1 is selected from the polyester family, the polyamide family, the polypropylene family and their mixtures, and - the polymer whose melting point is Tfusion2 is chosen,regardless of the polymer whose melting point is Tfusioni, among the polyester family, the polyamide family, the polypropylene family and their mixtures.

2. Matelassure according to claim 1, wherein the matrix fibers have a length between 5 mm and 150 mm and a count between 2 dtex and 60 dtex.

3. Matelassure according to claim 1 or claim 2 wherein the matrix fibers are selected from fibers of the polyester family, fibers of the polyamide family, or fibers of the polypropylene family and mixtures thereof.

4. Matelassure according to any one of claims 1 to 3 wherein the two-component fibers have a core / coat morphology and the coat polymer has melting point Tfusion1 and the core polymer has melting point Tfusion2.

5. Matelassure according to any one of claims 1 to 4 wherein, for each fiber bead, the mass ratio of matrix fibers:two-component fibers is between 1:0.1 and 1:

3.

6. Method for producing a mattress as defined in one any of claims 1 to 5, the process comprising the following steps: a) mixing matrix fibers and two-component fibers to obtain a fiber mixture, b) producing fiber balls from the fiber mixture, and c) molding the mattress from the fiber balls.

7. A method according to claim 6 wherein the molding production step c) is carried out in the following substeps: c1) incorporation of fiber balls into a mold, c2) closing of the mold, and then c3) injection of hot air into the mold.

8. A method according to claim 6 or claim 7 wherein the hot air temperature is above the melting point, Tfusioni, of the polymer in the bicomponent fiber cladding.

9. A method according to any one of claims 6 to 8 further comprising, between step a) and step b) one or more steps of working the fiber mixture to obtain a homogenized fiber mixture, said homogenized fiber mixture being subsequently used in production step b).

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