METHOD AND PLANT FOR PRODUCING A FILLING MATERIAL AND FILLING MATERIAL

Abstract

A method for producing a filling material comprising goose and/or duck down and vegetable kapok fibres comprises feeding vegetable kapok fibre to a mixing chamber (16), separating elementary kapok filaments (210) unbound from each other from the vegetable kapok fibre in the mixing chamber (16) by directing jets and/or blades of a pressurized fluid against the vegetable kapok fibre, feeding goose and/or duck down to the mixing chamber (16) and incorporating elementary kapok filaments (210) unbound from each other into the flakes (101) of goose and/or duck down (100) by mixing the elementary kapok filaments (210) and the goose and/or duck down in the mixing chamber (16) by means of said jets and/or blades of pressurized fluid fed for example by suitably oriented nozzles (33).

Claims

1-32. (canceled)

33. A method for producing a filling material comprising: feeding vegetable kapok fibre to a mixing chamber; separating elementary kapok filaments unbound from each other from the vegetable kapok fibre in said mixing chamber by directing jets and/or blades of a pressurized fluid against said vegetable kapok fibre; feeding goose and/or duck down to said mixing chamber; and incorporating elementary kapok filaments unbound from each other into flakes of goose and/or duck down by mixing said elementary kapok filaments and said goose and/or duck down in said mixing chamber by means of said jets and/or blades of pressurised fluid.

34. The method according to claim 33, wherein separating the elementary kapok filaments unbound from each other from the vegetable kapok fibre comprises forming disentangled vegetable kapok fibre made of clusters of elementary filaments bound to each other and having a weight equal to or lower than 0.05 grams.

35. The method according to claim 33, wherein incorporating said elementary kapok filaments into the flakes of goose and/or duck down takes place in said mixing chamber simultaneously with separating the elementary kapok filaments unbound from each other from the vegetable kapok fibre.

36. The method according claim 34, comprising mixing said disentangled vegetable kapok fibres with said goose and/or duck down.

37. The method according to claim 36, wherein incorporating elementary kapok filaments unbound from each other into the flakes of goose and/or duck down and mixing said disentangled vegetable kapok fibres with said goose and/or duck down take place simultaneously.

38. The method according to claim 36, wherein mixing said disentangled vegetable kapok fibres with said goose and/or duck down is carried out by holding the disentangled vegetable kapok fibres and the goose and/or duck down in suspension in said mixing chamber.

39. The method according to claim 33, wherein separating the elementary kapok filaments unbound from each other from the vegetable kapok fibre is carried out by holding the vegetable kapok fibre in suspension in the mixing chamber.

40. The method according to claim 39, wherein holding the elementary kapok filaments, the goose and/or duck down or the disentangled vegetable kapok fibres in suspension is at least partially carried out by means of said jets and/or blades of pressurized fluid.

41. The method according to claim 39, wherein holding the elementary kapok filaments, the goose and/or duck down or the disentangled vegetable kapok fibres in suspension is at least partially carried out by means of a comb rotating within the mixing chamber.

42. The method according to claim 33, wherein incorporating elementary kapok filaments unbound from each other into the flakes of goose and/or duck down is carried out by holding the elementary kapok filaments and the goose and/or duck down in suspension in said mixing chamber.

43. The method according to claim 33, wherein directing jets and/or blades of a pressurized fluid against said vegetable kapok fibre comprises feeding said pressurized fluid into said mixing chamber at a pressure equal to or greater than 0.1 MPa.

44. The method according to claim 33, wherein directing jets and/or blades of a pressurized fluid against said vegetable kapok fibre comprises feeding compressed gas into the mixing chamber by means of a plurality of feeding nozzles and/or feeding slots.

45. The method according to claim 44, wherein the mixing chamber is defined in a mixing cylinder and wherein said feeding nozzles and/or feeding slots of the pressurized fluid are arranged in pairs substantially opposite to each other and facing an internal volume of the mixing chamber.

46. The method according to claim 33, wherein the ratio between the weight in kilograms given by the sum of the weight of the down and of the vegetable kapok fibre fed into the mixing chamber and the volume of the mixing chamber measured in cubic meters is between 0.2 and 5.

47. The method according to claim 33, comprising subjecting the vegetable kapok fibre to partial disentangling before feeding the vegetable kapok fibre to the mixing chamber.

48. The method according to claim 47, wherein said partial disentangling of the vegetable kapok fibre comprises directing jets and/or blades of a pressurized fluid against the vegetable kapok fibre along a feeding path of the vegetable kapok fibres to the mixing chamber.

49. The method according to claim 48, wherein directing jets and/or blades of a pressurized fluid against said vegetable kapok fibre comprises feeding compressed gas in the feeding path of the vegetable kapok fibres to the mixing chamber by means of a plurality of feeding nozzles and/or feeding slots.

50. The method according to claim 48, wherein subjecting the vegetable kapok fibre to partial disentangling is carried out by holding the vegetable kapok fibre in suspension in the feeding path of the vegetable kapok fibres to the mixing chamber.

51. The method according to claim 50, wherein holding the vegetable kapok fibre in suspension in the feeding path of the vegetable kapok fibres to the mixing chamber is at least partially carried out by means of said jets and/or blades of pressurized fluid.

52. The method according to claim 48, wherein directing jets and/or blades of a pressurized fluid against said vegetable kapok fibre comprises feeding said pressurized fluid in the feeding path of the vegetable kapok fibres to the mixing chamber at a pressure equal to or greater than 0.1 MPa.

53. The method according to claim 47, wherein said partial disentangling of the vegetable kapok fibre comprises directing jets and/or blades of a pressurized fluid against the vegetable kapok fibre in a pre-treatment chamber positioned upstream of said mixing chamber.

54. The method according to claim 53, wherein directing jets and/or blades of a pressurized fluid against said vegetable kapok fibre comprises feeding compressed gas in the pre-treatment chamber by means of a plurality of feeding nozzles and/or feeding slots.

55. The method according to claim 53, wherein subjecting the vegetable kapok fibre to partial disentangling is carried out by holding the vegetable kapok fibre in suspension in the pre-treatment chamber.

56. The method according to claim 55, wherein holding the vegetable kapok fibre in suspension in the pre-treatment chamber is at least partially carried out by means of said jets and/or blades of pressurized fluid.

57. The method according to claim 55, wherein holding the vegetable kapok fibre in suspension in the pre-treatment chamber is at least partially carried out by means of a comb rotating within the pre-treatment chamber.

58. The method according to claim 53, wherein directing jets and/or blades of a pressurized fluid against said vegetable kapok fibre comprises feeding said pressurized fluid in the pre-treatment chamber at a pressure equal to or greater than 0.1 MPa.

59. The method according to claim 53, wherein the ratio between the weight in kilograms of the vegetable kapok fibre present in the pre-treatment chamber and the volume of the pre-treatment chamber measured in cubic meters is between 0.5 and 10.0.

60. A plant for producing a filling material comprising goose and/or duck down and vegetable kapok fibres, wherein the plant comprises: a mixing chamber of flakes of goose and/or duck down and of the vegetable kapok fibres; and a plurality of feeding nozzles and/or feeding slots of a pressurized fluid, in fluid communication with a pressurized fluid source, wherein each feeding nozzle and/or feeding slot faces an internal volume of the mixing chamber and is oriented to direct jets and/or blades of the pressurized fluid towards said internal volume.

61. The plant according to claim 60, wherein said feeding nozzles and/or feeding slots are arranged according to one or more pairs positioned at substantially opposite parts of the mixing chamber.

62. The plant according to claim 60, wherein said mixing chamber is defined in a mixing cylinder.

63. The plant according to claim 60, further comprising: a pre-treatment chamber of the vegetable kapok fibre positioned upstream of said mixing chamber; and a plurality of feeding nozzles and/or feeding slots of a pressurized fluid, in fluid communication with a pressurized fluid source, wherein each feeding nozzle and/or feeding slot faces an internal volume of said pre-treatment chamber and is oriented to direct jets and/or blades of the pressurized fluid towards said internal volume.

64. The plant according to claim 63, wherein said feeding nozzles and/or feeding slots are arranged according to one or more pairs positioned at substantially opposite parts of the pre-treatment chamber.

65. The plant according to claim 63, wherein said pre-treatment chamber of the vegetable kapok fibre is defined in a container of a pre-treatment apparatus of the vegetable kapok fibre positioned upstream of said mixing chamber.

66. The plant according to claim 63, wherein said pre-treatment chamber of the vegetable kapok fibre is defined in a feeding conduit of the vegetable kapok fibre to said mixing chamber.

67. The plant according to claim 63, further comprising a comb rotating within the pre-treatment chamber of the vegetable kapok fibre.

68. The plant according to claim 60, further comprising a comb rotating within the mixing chamber.

69. A filling material comprising goose and/or duck down and vegetable kapok fibres, comprising: a) hybrid goose and/or duck down comprising elementary kapok filaments unbound from each other incorporated in flakes of goose and/or duck down in an amount equal to or greater than 10% by weight of the total weight of kapok, and/or b1) goose and/or duck down, and b2) disentangled kapok fibres, made of clusters of elementary kapok filaments unbound from each other and not incorporated in the down flakes, and having a weight equal to or greater than 0.05 g, and in an amount equal to or lower than 20% by weight of the total weight of kapok.

70. The filling material according to claim 69, wherein the disentangled kapok fibers are in an amount equal to or lower than 15% by weight of the total weight of kapok.

71. The filling material according to claim 69, comprising a total amount of vegetable kapok fibres between 5% and 80% by weight of the total weight of the filling material.

72. The filling material according to claim 69, comprising a total amount of vegetable kapok fibres between 10% and 75% by weight of the total weight of the filling material.

73. The filling material according to claim 69, comprising a total amount of vegetable kapok fibres between 10% and 50% by weight of the total weight of the filling material.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0166] Additional features and advantages of the invention will be more readily apparent from the following description of preferred embodiments thereof made with reference to the attached drawings, wherein:

[0167] FIG. 1 is a diagram of a possible preferred embodiment of a plant for carrying out a method for producing filling material according to the present invention;

[0168] FIGS. 2 and 3 are schematic representations of a detail of the plant of FIG. 1;

[0169] FIGS. 4 and 5 are schematic representations of a further detail of the plant in FIG. 1;

[0170] FIG. 6 is a schematic view of a down flake;

[0171] FIG. 7 is a 20-fold magnified view of an elementary kapok filament;

[0172] FIG. 8 is a view of disentangled vegetable kapok fibres according to the invention; and

[0173] FIG. 9 is a schematic view of a hybrid down flake incorporating elementary kapok filaments.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS OF THE INVENTION

[0174] FIG. 1 schematically illustrates a preferred embodiment of a plant 10 for producing a filling material comprising elementary kapok filaments unbound from each other incorporated in flakes of goose and/or duck down according to the present invention.

[0175] For the sake of simplicity, the plant 10 will be illustrated below with reference to a preferred embodiment of a method according to the invention for producing a filling material comprising elementary kapok filaments unbound from each other incorporated in flakes of goose and/or duck down to form hybrid flakes.

[0176] Preferably, the method for producing filling material comprises introducing an amount of down 100 into a collector device 11.

[0177] The amount of down introduced into the collector device 11 is not necessarily predetermined but may for example be the amount of down 100 contained in one or more bags typically used for the sale of down 100.

[0178] The down 100 is goose and/or duck down and is mostly in the form of flakes 101.

[0179] FIG. 6 schematically illustrates the typical, but not exclusive structure of such a flake 101. The flake 101 is devoid of calamus and rachis and comprises a plurality of substantially independent barbs or barbules 102 which do not form a consistent vexillum. The barbules 102 of the flake 101 have a substantially elongated shape to form an open canopy-like structure.

[0180] The down 100 introduced into the collector device 11 is transferred by a pneumatic loading line 12 into a hopper 13. A weighing device 14, for example a load cell, is provided at the base of the hopper 13.

[0181] The pneumatic loading line 12 creates a forced-air transport line that transports the down from the collector device 11 to the hopper 13. The pneumatic loading line 12 may be a conduit with diameter preferably between 10 and 30 centimetres, for example 20 centimetres, in which a pressure difference is created between inlet 12a and outlet 12b, for example by using an air blower such as a fan. The inlet 12a is located at the collector device 11 and the outlet 12b is located at the hopper 13. The pressure difference is such that the pressure at the inlet 12a is lower than the ambient pressure and the pressure at the outlet 12b, so as to create an air flow that transports the down 100 into the hopper 13.

[0182] The weighing device 14 has the function of weighing a predetermined amount of down 100 as a function of the type of filling to be produced.

[0183] In a working example to which reference will be made, the amount of down 100 used is equal to 70% by weight with respect to the total weight of the filling material.

[0184] In the example described, the filling material has a total weight of 5 kg. Thus, the weighing device 14 is set to weigh 3.5 kg of down 100.

[0185] The down 100 thus weighed is sent to a conveyor device (not illustrated), such as for example a conveyor belt, to be transferred to a homogenization container 15.

[0186] The function of the homogenization container 15 is to stir the down 100 in such a way as to separate the flakes 101 from each other (at least in part), to prevent the formation of agglomerates of flakes 101 and to separate any agglomerates of flakes 101 into single flakes 101 or at least into smaller agglomerates of flakes 101.

[0187] An example of a homogenization container 15 may be a container within which a plurality of paddles or combs rotate that intercept the down 100 stirring the latter and separating the down flakes from each other.

[0188] The stirred down 100 is sent to a mixing chamber 16.

[0189] To this end, the homogenization container 15 comprises an outlet 17 for the stirred down. The outlet 17 is connected to an inlet 18 of the mixing chamber 16 through a pneumatic feeding line 19. The pneumatic feeding line 19 may be a conduit having a diameter between 10 and 30 centimetres, for example 20 centimetres, in which a pressure difference is created between the outlet 17 from the homogenization container 15 and the inlet 18 into the mixing chamber 16, for example by using an air blower such as a fan. The pressure difference is such that the pressure at the outlet 17 is lower than the pressure at the inlet 18, so as to create an air flow that transports the stirred down 100 into the mixing chamber 16.

[0190] Alternatively, the down 100 may be directly sent to the mixing chamber 16 without being introduced into the homogenization container 15. In this case, the down 100 weighed in the weighing device 14 is directly introduced into the mixing chamber 16 for example through a conduit in which a flow of transport air moves through or by dropping from the weighing device 14.

[0191] The method for producing the filling material also envisages introducing an amount of vegetable kapok fibre into a collector device 20. The amount of vegetable kapok fibre introduced into the collector device 20 is not necessarily predetermined but may for example be the amount of vegetable kapok fibre contained in one or more bags typically used for the sale of vegetable kapok fibre.

[0192] The vegetable kapok fibre introduced into the collector device 20 is transferred by a pneumatic kapok loading line 21 into a hopper 22. A weighing device 23, for example a load cell, is provided at the base of the hopper 22.

[0193] The pneumatic kapok loading line 21 creates a forced-air transport line that transports the vegetable kapok fibre from the collector device 20 to the hopper 22. The pneumatic kapok loading line 21 may be a conduit with diameter between 10 and 30 centimetres, for example 20 centimetres, in which a pressure difference is created between inlet 21a and outlet 21b, for example by using an air blower such as a fan. The inlet 21a is placed at the collector device 20 dedicated to the kapok and the outlet 22b is placed at the hopper 22 dedicated to the kapok. The pressure difference is such that the pressure at the inlet 21a is lower than the ambient pressure and the pressure at the outlet 21b, so as to create an air flow that transports the vegetable kapok fibre into the hopper 22.

[0194] The weighing device 23 has the function of weighing a predetermined amount of vegetable kapok fibre as a function of the type of filling to be produced.

[0195] In the example to which reference is made, the amount of vegetable kapok fibre used is equal to 30% by weight with respect to the total weight of the filling material.

[0196] Thus, the weighing device 23 is set to weigh 1.5 kg of vegetable kapok fibre.

[0197] In a preferred embodiment, the vegetable kapok fibre thus weighed is sent to a conveyor device (not illustrated), such as for example a conveyor belt, to be transferred in a pre-treatment chamber 24.

[0198] In the preferred embodiment illustrated in the figures, the pre-treatment chamber of the vegetable kapok fibre 24 is defined in a container of a pre-treatment apparatus of the vegetable kapok fibre positioned upstream of the mixing chamber 16 and comprising, in this exemplary embodiment, the hopper 22 and the weighing device 23.

[0199] In this preferred embodiment, the vegetable kapok fibre is subjected to partial disentangling in the pre-treatment chamber 24 to obtain elementary kapok filaments 210 and disentangled vegetable kapok fibres 220 made of clusters of elementary filaments bound to each other and having a weight equal to or lower than 0.05 grams.

[0200] The elementary filaments 210 and the disentangled vegetable kapok fibres 220 are shown in FIGS. 7 and 8 respectively.

[0201] As better shown in FIG. 2 and in order to implement this step of partially disentangling the vegetable kapok fibre, the pre-treatment chamber 24 comprises a plurality of nozzles 25, for example eight nozzles 25, configured to deliver a suitable pressurized fluid, for example and preferably, compressed air, within the pre-treatment chamber 24.

[0202] Preferably, each nozzle 25 faces an internal volume 26 of the pre-treatment chamber 24 and is oriented to direct straight jets of the pressurized fluid towards said internal volume 26.

[0203] Preferably, the feeding nozzles 25 are arranged according to a plurality of pairs, in this exemplary case four pairs, positioned at substantially opposite parts of the pre-treatment chamber 24.

[0204] Preferably, the feeding nozzles 25 are arranged in arrays positioned at transversely opposite parts with respect to a longitudinal axis of the pre-treatment chamber 24.

[0205] The nozzles 25 are connected in a manner known per se to a source of pressurized fluid, for example in this case, compressed air, and are configured to feed compressed air at a pressure greater than 0.1 MPa, for example between 0.6 Mpa and 0.7 Mpa, within the pre-treatment chamber 24 and against the vegetable kapok fibre.

[0206] Preferably, the feeding nozzles 25 feed compressed air into the pre-treatment chamber 24 during the transit of the vegetable kapok fibres within the pre-treatment chamber 24.

[0207] Conveniently, the pre-treatment chamber 24 is not hermetically sealed but is in fluid communication with the external environment to prevent the internal pressure from equalizing the feeding pressure of the feeding nozzles 25.

[0208] Preferably, the conveyor device for the vegetable kapok fibre weighed by the weighing device 23 introduces successive portions of vegetable kapok fibre into the pre-treatment chamber 24 in such a way that the feeding nozzles 25 act on limited portions of the entire amount of vegetable kapok fibre that must be subsequently mixed with the down in the mixing chamber 16.

[0209] In particular, the conveyor device and the pre-treatment chamber 24 are preferably configured such that the ratio between the weight (in kilograms) of the vegetable kapok fibre present in the pre-treatment chamber 24 and the volume of the container measured in cubic metres is between 0.5 and 10, and, more preferably, between 1.0 and 6.0. In a particularly preferred embodiment, this ratio is between about 2.0 and 4.8.

[0210] By way of example, in a preferred embodiment the pre-treatment chamber 24 has a length of about 1.4 metres, a width of about 0.35 metres and a height of about 0.65 metres.

[0211] Preferably, each portion of vegetable kapok fibre introduced into the pre-treatment chamber 24 has a weight between 0.5 and 0.8 kilograms.

[0212] Preferably, the vegetable kapok fibre is fed in successive portions and continuously into the pre-treatment chamber 24 so that it travels through the latter before reaching the mixing chamber 16.

[0213] By way of example, an amount of about 1.5 kg of vegetable kapok fibre is fed in successive portions and continuously into the pre-treatment chamber 24, taking about 3 minutes to pass completely and continuously through the pre-treatment chamber 24.

[0214] In the preferred embodiment illustrated, the pre-treatment chamber 24 comprises a rotating comb 27 arranged within the chamber and rotatable about a substantially horizontal axis that preferably extends along the entire length of the pre-treatment chamber 24.

[0215] Advantageously, the rotating comb 27 operates in the internal volume 26 of the pre-treatment chamber 24 and acts on the vegetable kapok fibre to help holding the fibre in suspension within the pre-treatment chamber 24 and expose the same more efficiently to the jets of compressed air delivered by the nozzles 25.

[0216] In the context of this preferred embodiment of the invention, this action of holding the vegetable kapok fibre in suspension within the pre-treatment chamber 24 is mainly carried out by the compressed air itself and is assisted by the rotating comb 27.

[0217] Preferably, the rotating comb 27 comprises a plurality of blades 28 radially extending from a central shaft 29.

[0218] Within the framework of this preferred embodiment, the central shaft 29 rotates about a horizontal axis of rotation, driving the blades 28 in rotation.

[0219] Within the framework of this preferred embodiment, therefore, the rotating comb 27 keeps the vegetable kapok fibres in constant motion in the pre-treatment chamber 24 during the feeding of compressed air.

[0220] Preferably, and as best illustrated in FIG. 3, the pre-treatment chamber 24 comprises a bottom curved wall 24a to define a concavity facing the internal volume 26 of the pre-treatment chamber 24.

[0221] Preferably, the bottom curved wall 24a has a development that is at least partly parallel to the trajectory followed by the blades 28 of the rotating comb 27.

[0222] Preferably, at an axial end of the pre-treatment chamber 24 there is an outlet 30 for the elementary filaments 210 and the disentangled vegetable kapok fibres 220 obtained from the said step of partial disentangling the vegetable kapok fibre carried out in the pre-treatment chamber 24.

[0223] Preferably, the outlet 30 is at a lower pressure with respect to the internal volume 26 of the pre-treatment chamber 24 in such a way that the elementary kapok filaments 210 and the disentangled vegetable kapok fibres 220 are sucked into the outlet 30.

[0224] In this preferred embodiment, the elementary kapok filaments 210 and the disentangled vegetable kapok fibres 220 are sent to the mixing chamber 16.

[0225] This transfer operation is preferably carried out by means of a pneumatic transfer line 31 connecting the outlet 30 of the pre-treatment chamber 24 to an inlet 32 of the mixing chamber 16.

[0226] The pneumatic transfer line 31 may be a conduit with diameter between 10 and 30 centimetres, for example 20 centimetres, in which a pressure difference is created between the outlet 30 from the pre-treatment chamber 24 and the inlet 32 into the mixing chamber 16. The pressure difference is such that the pressure at the outlet 30 is lower than the pressure at the inlet 32, so as to create an air flow that transports the elementary filaments 210 and the disentangled vegetable kapok fibres 220 into the mixing chamber 16.

[0227] Alternatively, the kapok fibre is directly fed to the mixing chamber 16 without passing through the pre-treatment chamber 24 or passing through the pre-treatment chamber 24 but without any jet of compressed air being directed onto the vegetable kapok fibres.

[0228] When the elementary filaments 210 and the disentangled vegetable kapok fibres 220 enter the mixing chamber 16, this preferred embodiment of the method comprises separating further elementary kapok filaments 210 unbound from each other from the disentangled vegetable kapok fibres 220 in the mixing chamber 16 by directing jets of a pressurized fluid, for example also in this case compressed air, against the vegetable kapok fibre as a whole and in particular against the disentangled vegetable kapok fibres 220.

[0229] To this end and as schematically shown in FIG. 4, the mixing chamber 16 comprises a plurality of feeding nozzles 33, for example eight nozzles 33, configured to deliver directed jets of a suitable pressurized fluid, for example and preferably compressed air, within the mixing chamber 16.

[0230] Preferably, each nozzle 33 faces an internal volume 34 of the mixing chamber 16 and is oriented to direct straight jets of the pressurized fluid towards said internal volume 34.

[0231] Preferably, the nozzles 33 are arranged according to a plurality of pairs, in this exemplary case four pairs, positioned at substantially opposite parts of the mixing chamber 16.

[0232] Preferably, the nozzles 33 are arranged according to arrays positioned at longitudinally opposite parts with respect to a longitudinal axis of the mixing chamber 16.

[0233] The nozzles 33 are connected in a manner known per se to a source of pressurized fluid, for example in this case, compressed air, and are configured to deliver compressed air at a pressure greater than 0.1 MPa, for example between 0.6 Mpa and 0.7 Mpa, within the mixing chamber 16 and against the vegetable kapok fibre present therein.

[0234] In this preferred embodiment, the vegetable kapok fibre present within the mixing chamber 16 essentially consists of the elementary filaments 210 and of the disentangled vegetable kapok fibres 220 previously obtained from the step of partial disentangling the kapok fibre carried out in the pre-treatment chamber 24.

[0235] Advantageously, by directing the jets of compressed air delivered by the nozzles 33 against the vegetable kapok fibre, it is possible to separate further elementary kapok filaments 210 unbound from each other from the disentangled vegetable kapok fibres 220 in the mixing chamber 16.

[0236] Advantageously, furthermore, the jets of compressed air delivered by the nozzles 33 prevent the elementary filaments 210 from aggregating again with each other or with the disentangled vegetable kapok fibres 220.

[0237] Subsequent to the introduction of the kapok into the mixing chamber 16 or simultaneously with the introduction of the kapok into the mixing chamber 16, the method of the invention comprises feeding the goose and/or duck down 100 into the mixing chamber 16.

[0238] Following such feeding of the down 100, the step of incorporating the elementary kapok filaments 210 unbound from each other into the flakes 101 of the down 100 is carried out in the mixing chamber 16 by mixing the elementary kapok filaments 210 and the down 100 by means of the jets of compressed air delivered by the nozzles 33.

[0239] In particular, within the mixing chamber 16, the elementary kapok filaments 210 join the down 100 in such a way as to bind themselves to the barbules 102 of the flakes 101 and be inserted into the flakes 101 themselves.

[0240] In order to carry out this incorporation process, the feeding nozzles 33 introduce compressed air into the mixing chamber 16 for the whole duration of the mixing process which, for example, may last about 5 minutes.

[0241] At the same time and analogously to what happens in the pre-treatment chamber 24, the directed jets delivered by the nozzles 33 facing the internal volume 34 of the mixing chamber 16 also carry out an additional disentangling of the vegetable kapok fibre to obtain disentangled vegetable kapok fibres 220 made of clusters of elementary filaments bound to each other and having a weight equal to or lower than 0.05 grams.

[0242] In an exemplary embodiment and as will better appear below, the step of disentangling the vegetable kapok fibres carried out in the mixing chamber 16 is such that about 66% by weight of the vegetable kapok fibre gives rise to elementary filaments 210 and about 34% by weight of the vegetable kapok fibre gives rise to disentangled vegetable kapok fibres 220 made of clusters of elementary filaments bound to each other and having a weight equal to or lower than 0.05 grams.

[0243] The Applicant has observed that by varying the residence time of the vegetable kapok fibres both inside the pre-treatment chamber 24 and inside the mixing chamber 16, the percentage of obtainable elementary filaments 210 and the percentage of the aforesaid disentangled vegetable kapok fibres 220 vary accordingly and in a mutually opposite way, i.e., in case of an increase in the residence time, the percentage of obtainable elementary filaments 210 increases and the percentage of the aforesaid disentangled vegetable kapok fibres 220 decreases, and vice versa in case of a decrease in the residence time.

[0244] Preferably and analogously to what is set forth above in relation to the pre-treatment chamber 24, the mixing chamber 16 is also not hermetically sealed but is in fluid communication with the external environment to prevent the internal pressure from equalizing the feeding pressure of the feeding nozzles 33.

[0245] Preferably, within the mixing chamber 16 the ratio between the sum of the weight of the introduced kapok and the weight of the introduced down 100 and the volume of the mixing chamber 16 measured in cubic metres is between 0.5 and 2. More preferably, this ratio is of about 1.

[0246] By way of example, in the preferred embodiment illustrated the mixing chamber 16 is defined in a stationary mixing cylinder 35 with horizontal axis of symmetry.

[0247] The mixing cylinder 35 is provided with a perforated side wall 37 and longitudinally opposite circular base walls 36. Preferably, the perforated side wall 37 of the mixing cylinder 35 comprises a plurality of holes preferably having diameters of a few millimetres (for example 0.9 to 1.2 mm).

[0248] Preferably, the length of the mixing cylinder 35 is about 1.7 metres and the diameter is about 1.7 metres.

[0249] As set forth above, the feeding nozzles 33 are preferably eight in number facing each other in pairs and are placed on the base walls 36 and side walls 37 (FIG. 4).

[0250] Preferably, the mixing chamber 16 comprises a rotating comb 38 rotatable about a substantially horizontal axis extending along the entire length of the mixing chamber 16 defined in the cylinder 35.

[0251] The rotating comb 38 operates in the internal volume 34 of the mixing chamber 16 and is intended to help holding the mixture contained in the mixing chamber 16 in suspension.

[0252] Advantageously, this action of holding the mixture in suspension is carried out in synergy with the jets of compressed air delivered into the mixing chamber 16 by the nozzles 33.

[0253] Preferably, the rotating comb 38 acts on the mixture of elementary filaments 210, on the disentangled vegetable kapok fibres 220 and on the down 100 throughout the mixing process.

[0254] Preferably, the rotating comb 38 comprises a plurality of blades 39 radially extending from a central shaft 40.

[0255] Preferably, the central shaft 40 rotates about the axis of symmetry of the mixing chamber 16 driving the blades 39 in rotation.

[0256] Preferably, the mixing cylinder 35 is contained in a prismatic housing 41.

[0257] Preferably, the step of mixing the down 100, the elementary filaments 210 and the disentangled vegetable kapok fibre 220 in the mixing chamber 16 may have a time span between about 2 minutes and about 12 minutes, for example of about 5 minutes, at the end of which the filling product is ready to be discharged from the mixing chamber 16 and stored in a manner known per se.

[0258] FIG. 9 shows a schematic representation of how a sample consisting of down flakes 101 and elementary kapok filaments 210 inserted into the flakes 101 of the down 100 may look like. The elementary kapok filaments 210 have been inserted between the barbules 102 of the flakes 101 of the down 100, producing a hybrid flake which maintains almost unchanged the original properties of a native down flake 101.

[0259] The invention is now further illustrated by means of the following Examples, intended for illustrative and non-limiting purposes, of preparation and testing of a filling material comprising goose and/or duck down and vegetable kapok fibres according to the present invention and according to the prior art.

Example 1—Preparation and Analysis of a Filling Material According to the Invention

[0260] A filling material comprising goose and/or duck down and vegetable kapok fibres was obtained starting from approximately 70 parts by weight of down and approximately 30 parts by weight of vegetable kapok fibre by implementing a preparation method as described in the previous paragraphs.

[0261] The filling material thus produced was analysed following the provisions of the IDFB (International Down and Feather Bureau) Testing Regulation protocol (version June 2020) with regard to cellulose-based fibres. The Applicant has in fact found that this protocol can also be effectively used to analyse the composition of down mixed with elementary filaments and kapok fibres, which are precisely cellulose-based fibres.

[0262] Specifically, this protocol explains how to prepare samples for analysing a composition of down mixed with cellulose-based fibres according to the definitions, tools and procedures referred to in the IDFB Testing Regulation part 3 (June 2020 version) entitled “Composition (Content Analysis)”.

[0263] The composition of the filling material was analysed by completing the first separation required in paragraphs a) to c) of the IDFB Testing Regulation part 15-B.2 and without carrying out what is required in paragraphs d) to g) of the IDFB Testing Regulation part 15-B.2 (second separation) (version June 2013).

[0264] The filling material analysed in this way gave the results shown in Table 1 below.

TABLE-US-00001 TABLE 1 Material Amount (% by weight) Down and fibres 86.1 Waterfowl feathers 2.8 Damaged feather 1.8 Feathers of land birds 0.1 Separable kapok fibres 9.2 weighing lower than 0.05 g Separable kapok fibres 0.0 weighing more than 0.05 g

[0265] In order to determine the actual total amount of down and kapok fibre present in the filling material, the latter was analysed according to the provisions of the IDFB Testing Regulation protocol part 15-D (version June 2019) entitled “Chemical Separation of Down and Feathers Blended with Cellulose”. This protocol explains how to separate down from cellulose. The Applicant has found that this protocol can also be effectively used to separate down from kapok.

[0266] The reported results of this further analysis are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Material Amount (% by weight) Down and Feathers 72.8 Kapok 27.2

[0267] In order to calculate the % by weight of manually separable kapok weighing lower than 0.05 g, the formula was applied: % cellulose <0.05 g manually separated/% cellulose found by chemical separation according to IDFB Testing Regulation part 15-D.

[0268] In this case: 9.2%/27.2%=33.7%.

[0269] In order to calculate the % by weight of manually separable kapok weighing more than 0.05 g, the formula was applied: % cellulose >0.05 g manually separated/% cellulose found by chemical separation according to IDFB Testing Regulation part 15-D.

[0270] In this case: 0%/27.2%=0%.

[0271] The calculation of the % by weight of perfectly mixed kapok (i.e. the % by weight of elementary kapok filaments retained by the barbules and therefore not mechanically separable from the flakes) was carried out using the formula: 100%−(sum of total percentage of unmixed Kapok).

[0272] In this case: 100%−(33.7%+0%)=66.3%.

Example 2—Preparation and Analysis of a Comparative Filling Material

[0273] A comparative filling material comprising goose and/or duck down and vegetable kapok fibres was prepared starting from about 70 parts by weight of down and about 30 parts by weight of vegetable kapok fibre using the same plant as described in the previous paragraphs without any feed of pressurized fluid jets and by only actuating the combs 27 and 38.

[0274] This to simulate the purely mechanical treatments of disentangling the vegetable fibre and of mixing it with the down, as provided for by the prior art.

[0275] The filling material had a very uneven structure with partially disentangled kapok fibres grouped together to form agglomerates weighing more than 0.05 g, which did not allow significant and reproducible results to be obtained in the tests carried out according to the above-mentioned IDFB protocol. This is because of the extreme variability in composition between the samples.

[0276] In this case, therefore, it was not possible to determine the presence and relative amount of elementary kapok filaments embedded in the down flakes. In any event, the Applicant has observed that the % by weight of partially disentangled kapok fibres weighing more than 0.05 g was on average higher than 30%.

Example 3—Assessment of Water Repellency of the Filling Material According to Example 1

[0277] The filling material obtained according to the example was also analysed following the provisions of the IDFB Testing Regulation part 18-A protocol (June 2015 version) entitled “Hydrophobic Shake Test”.

[0278] This protocol explains how to assess the water repellency of the composition and allows information to be inferred about the degree of mixing between the kapok fibres (which tend to float on the liquid) and down (which tend to soak and sink into the liquid).

[0279] The filling material according to Example 1 (invention) after 100 minutes of Shake test reached a level 3 (Bulk down is half way under water), whereas a reference filling material including only down reached after 100 minutes a level 5 (Down completely submerged under water—complete saturation).

[0280] This result confirms that in the filling material obtained according to Example 1 according to the invention, an optimal mixing of kapok and down takes place. In this case, the kapok is in fact able to exert its floating action on the filling material under the shake test conditions.

[0281] Conversely, the filling material including only down resulted as completely soaked and submerged under the shake test conditions.