JP2014065382A - Air conditioning duct and method for manufacturing same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dropping of dew condensation.SOLUTION: A split body 12 constituting an air conditioning duct 10 is made of a foam of an independent bubble structure, and comprises: an inner layer part 16 facing an air distribution path 11; and an outer layer part 18 made of unwoven cloth including at least a thermoplastic resin fiber and facing the outside while covering the entire outside of the inner layer part 16. The outer layer part 18 is formed to couple a part of the fiber by deposition of the thermoplastic resin fiber leave a gap between the fibers to communicate with the outside. The outer layer part 18 includes two thermoplastic resins different from each other in melting point, and formed by deposition of only the thermoplastic resin lower in melting point.

Description

  The present invention relates to an air conditioning duct that is attached to a vehicle and guides temperature-controlled air delivered from an air conditioning unit, and a method for manufacturing the air conditioning duct.

  In a vehicle, for example, an air conditioning duct is provided between an air conditioner unit and a ventilator disposed on an instrument panel, and temperature-controlled air sent from the air conditioner unit is guided by the air conditioning duct and blown out from the ventilator. . As an air conditioning duct, a synthetic resin solid body obtained by blow molding high density polyethylene or the like is often used. The air-conditioning duct made of such a solid body has poor heat insulation properties, so that it is cooled by the cold air flowing inside, causing condensation on the outer surface, and if this condensation drops, it may adversely affect the equipment installed in the vicinity. is there. For this reason, the sheet | seat material excellent in heat insulation, such as a polyurethane foam, is wound around the outer surface of an air-conditioning duct, and it is made hard to produce dew condensation on an outer surface.

  As described above, an air conditioning duct made of a solid body is inferior in heat insulation and relatively heavy. Therefore, an air conditioning duct obtained by vacuum forming a foam sheet such as polypropylene foam has also been proposed (for example, patents). Reference 1). The air-conditioning duct made of such a foam has excellent heat insulating properties as compared with the solid body, and therefore can suppress condensation occurring on the outer surface.

JP 2002-154314 A

  The air conditioning duct made of the solid body takes time and effort to wind the sheet material in order to prevent dew condensation, and it is difficult to wind the sheet material around the entire outer surface where the curved piece or the protruding piece for mounting is provided, Condensation that occurs on the outer surface exposed from the sheet material cannot be suppressed. The air-conditioning duct made of a foam is less likely to cause condensation than a solid body, but it does not change if the cold air continues to flow, and does not prevent the condensation from dripping. In addition, the air conditioning duct made of foam is inferior in rigidity to the solid body, and thus has a drawback that reinforcement is required.

  That is, the present invention has been proposed in view of the above-described problems related to the prior art, and provides an air-conditioning duct capable of preventing dripping of condensation on the outer surface and a method for manufacturing the same. For the purpose.

In order to overcome the above-mentioned problems and achieve the intended purpose, an air-conditioning duct according to claim 1 of the present application is
In the air conditioning duct that is formed into a cylindrical shape by a plurality of divided bodies joined to each other at the edge, and attached to the vehicle,
Of the plurality of divided bodies, the divided body including the lower portion when attached to the vehicle is made of a foam having a closed cell structure, and is composed of an inner layer portion facing the air flow passage and a nonwoven fabric including at least thermoplastic resin fibers. Consisting of an outer layer portion covering the entire outer side of the inner layer portion and facing outward,
The gist is that the outer layer portion is formed so as to bond a part of the fibers by welding the thermoplastic resin fibers and leave a void communicating between the fibers outward.
According to the first aspect of the present invention, the divided body including the lower portion when attached to the vehicle has a part of the outer layer portion facing outward so that a gap is left between the fibers and communicates outward. Since it is the structure shape | molded by welding of a fiber, dew condensation can be absorbed and hold | maintained in an outer layer part. In other words, the condensation that has occurred on the outer surface of the outer layer part and the condensation that has flowed down from the other divided body on the upper side when attached to the vehicle is absorbed and retained by the outer layer part, so that the condensation from the air conditioning duct is dropped. Can be prevented. In addition, the entire shape can be maintained by the outer layer portion whose rigidity has been improved by combining some of the fibers.

The gist of the invention according to claim 2 is that all the divided bodies include the inner layer portion and the outer layer portion.
According to the invention which concerns on Claim 2, since all the division bodies are equipped with the inner layer part and the outer layer part, heat insulation, rigidity, and sound deadening can be united at a high level as a whole.

The gist of the invention according to claim 3 is that the outer layer portion includes two thermoplastic resins having different melting points, and is formed by welding only a thermoplastic resin having a lower melting point.
According to the invention of claim 3, in the outer layer portion made of a nonwoven fabric, some fibers can be bonded and held in shape by welding with a thermoplastic resin having a low melting point, and voids can be secured between the fibers.

In order to overcome the above-mentioned problems and achieve the intended purpose, a method for manufacturing an air-conditioning duct according to claim 4 of the present application,
A laminated sheet obtained by laminating a foam sheet made of a foam having a closed cell structure and a nonwoven fabric sheet made of a nonwoven fabric containing at least thermoplastic resin fibers is heated until the thermoplastic resin fibers are melted,
In the state where the two laminated sheets face each other with the foam sheet facing each other, the overlapped edge portion is sandwiched between molds,
Air is sucked from the nonwoven fabric sheet side with the molding die, the nonwoven fabric sheet is pressed against the molding surface of the molding die, and each laminated sheet is vacuum-formed to form a divided body, and the edge part is self-fused. Then, the divided bodies are combined to form a cylinder,
The inner layer portion facing the air flow passage is made of the foam, and the outer layer portion covering the entire outer side of the inner layer portion and facing outward is left in the thermoplastic resin fiber while leaving a void communicating between the fibers. The gist of the present invention is that it is composed of the nonwoven fabric in which a part of the fibers are bonded by welding.
According to the invention which concerns on Claim 4, since formation of two division bodies and joining of these division bodies can be performed by the same process, an air-conditioning duct can be manufactured efficiently. And according to the obtained air conditioning duct, the condensation generated on the outer surface can be absorbed and retained by the outer layer portion to prevent dripping of the condensation from the air conditioning duct, and at the same time, the heat insulation, rigidity and sound deadening properties are high. I'm holding in. Moreover, since the laminated sheet is formed by laminating foam sheets having a closed cell structure, vacuum forming is possible.

The gist of the invention according to claim 5 is that air is press-fitted between the two laminated sheets during the vacuum forming.
According to the invention which concerns on Claim 5, the inner surface of the inner layer part which faces an airflow path can be prepared by pushing a division body toward a molding surface from the foam sheet side.

  According to the air conditioning duct and the method of manufacturing the same according to the present invention, it is possible to prevent dripping of condensation that has occurred on the outer surface of the air conditioning duct.

It is a schematic perspective view which shows the air-conditioning duct based on the Example of this invention. It is a schematic perspective view which shows the air-conditioning duct of an Example in the state which isolate | separated the division body. It is a schematic diagram explaining the cross section fractured | ruptured by the AA line of FIG. It is explanatory drawing which shows the manufacturing process of the air-conditioning duct of an Example, (a) shows a heating process, (b) shows a formation process.

  Next, a preferred embodiment of the air conditioning duct and the manufacturing method thereof according to the present invention will be described below with reference to the accompanying drawings.

  The air conditioning duct 10 according to the embodiment is attached to a vehicle such as an automobile, and is used to guide temperature-controlled air sent from an air conditioner unit to a ventilator provided on a vehicle interior member such as an instrument panel. As shown in FIG. 1, an air conditioning duct 10 according to the embodiment is a cylindrical body in which an air flow passage 11 through which air can flow is defined, and a plurality of (two in the embodiment) divided bodies. 12A and 12B are configured by joining edge portions along the air flow direction to each other. The air-conditioning duct 10 of the embodiment is curved and attached to the vehicle in a horizontal pulling posture in which the air flow passage 11 is along a horizontal plane and the openings 10a and 10a at both ends are sideways.

  As shown in FIG. 3, the air-conditioning duct 10 includes a composite body 12A including at least a lower portion when attached to a vehicle, and is composed of an inner layer portion 16 made of foam and an outer layer portion 18 made of nonwoven fabric. Layered structure. That is, in the embodiment, the first divided body 12 </ b> A that constitutes the lower half of the air conditioning duct 10 when attached to the vehicle has a multilayer structure including the inner layer portion 16 and the outer layer portion 18. Further, in the air conditioning duct 10, the divided body 12B that does not include the lower portion when attached to the vehicle is configured by a single layer of a synthetic resin solid body, foam, nonwoven fabric, or the like, or a multilayer of these layers. be able to. In the embodiment, the second divided body 12B constituting the upper half of the air-conditioning duct 10 when attached to the vehicle has a multilayer structure composed of the inner layer portion 16 and the outer layer portion 18 like the first divided body 12A. Yes. In other words, the air-conditioning duct 10 only needs to have at least a multi-layer structure at the lower side when attached to the vehicle. In the embodiment, all the divided bodies 12A and 12B have a multi-layer structure, and the air flow path 11 the entire circumference is defined by the inner layer portion 16, and the entire outer surface of the air conditioning duct 10 is constituted by the outer layer portion 18. Here, the lower part of the air conditioning duct 10 when attached to the vehicle refers to a part corresponding to the downstream side in the downflow direction where condensation that occurs on the outer surface of the air conditioning duct 10 flows down. If there is a lower end portion of the bottom surface and the side surface, it is a lower end portion if it is a longitudinal drawing portion of the air conditioning duct 10.

  Next, the divided body 12 will be described more specifically. In the embodiment, the basic configurations of all the divided bodies 12A and 12B are the same, and therefore will be described together. As shown in FIG. 2, the divided body 12 has a main body portion formed in a substantially eaves-like shape in which a groove extends in the air flow direction of the air-conditioning duct 10, and at each end edge portion along the air flow direction of the main body portion. A flange portion 14 extending outward is formed. The air conditioning duct 10 combines the two divided bodies 12A and 12B into a cylindrical shape by abutting the flange portions 14 on both sides, and joining the abutted flange portions 14 to integrate the divided bodies 12A and 12B. (See FIG. 1 or FIG. 3). For joining the two divided bodies 12A and 12B, an adhesive such as a reaction system, a solution system, an aqueous dispersion system, a hot melt, or a self-bonding of a material constituting the joint surface of the flange portion 14 can be used. In the embodiment, the thermoplastic resin foams constituting the joining surface of the flange portion 14 are joined by self-fusion.

  As shown in FIG. 3, the divided body 12 is made of a foam having a closed cell structure, and is composed of an inner layer portion 16 facing the air flow passage 11 and a non-woven fabric, covering the entire outer side of the inner layer portion 16 and facing outward. Part 18. In the divided body 12, the inner layer portion 16 and the outer layer portion 18 are adhesives such as a reaction system, a solution system, a water dispersion system, and a hot melt, thermal welding, and physical anchors by one entering the other structure. They are joined to each other due to effects or the like. In addition, the division body 12 is formed in the said shape by thermoforming the lamination sheet 20 which piled up the foam sheet 22 and the nonwoven fabric sheet 24 (refer FIG. 4).

  As the foam constituting the inner layer portion 16, an olefin-based thermoplastic resin foam such as polyethylene or polypropylene, a polyurethane foam, or the like can be used. Further, the inner layer portion 16 is configured by a foam having a closed cell structure, so that air flow in the inner and outer directions of the air conditioning duct 10 can be prevented. Here, the soft foam is used for the inner layer part 16, and it has elasticity unlike the film made from a synthetic resin generally used for an air-conditioning duct for airtightness. Furthermore, the inner layer portion 16 may be in any state in which the foam is not compressed, even if it is compression-molded within a range where the foam bubbles are not completely crushed.

  The outer layer portion 18 is obtained by heat-compressing the nonwoven fabric sheet 24 to such an extent that the nonwoven fabric remains in the fiber, and a part of the fibers are bonded by the welding of the thermoplastic resin fibers and communicated outwardly between the fibers. The voids are formed so as to remain. That is, the outer layer portion 18 is three-dimensionally formed by thermoforming a nonwoven fabric sheet 24 in which a web obtained by, for example, a spunbond method or the like is bonded by a needle punch method or the like, with some fibers and voids bonded and solidified to each other. It has a network-like skeleton. As the non-woven fabric constituting the outer layer portion 18, one containing at least thermoplastic resin fibers made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate or the like is used. As the nonwoven fabric, all fibers may be composed of thermoplastic resin fibers, or a combination of thermoplastic resin fibers, thermosetting resin fibers, and other fibers (for example, glass fibers). Moreover, you may shape | mold the outer layer part 18 by welding only the thermoplastic resin with a lower melting | fusing point using the nonwoven fabric containing two thermoplastic resins from which melting | fusing point differs. Here, the two thermoplastic resins having different melting points may be, for example, different types of combinations of polypropylene and polyethylene, or the same type in which two polyethylene terephthalates having different melting points are combined. In the embodiment, as fibers constituting the nonwoven fabric, a core part made of a first thermoplastic resin and a sheath part made of a second thermoplastic resin having a melting point lower than that of the first thermoplastic resin and covering the outer periphery of the core part A so-called core-sheath structure composed of Then, the outer layer portion 18 is welded and bonded only to the sheath portion without melting the core portion, thereby becoming a knot point where the sheath portions are bonded to each other, thereby restricting the free movement and leaving the fiber state. However, the shape of the outer layer portion 18 (divided body 12) can be maintained.

  As described above, the air conditioning duct 10 has an airtight structure by the inner layer portion 16, and the entire shape is maintained by welding of the fibers in the outer layer portion 18 that covers the entire outside of the inner layer portion 16. And as for the air-conditioning duct 10, the outer layer part 18 which left the fiber state of the nonwoven fabric has water absorption and water retention.

  Next, the manufacturing method of the air-conditioning duct 10 which concerns on an Example is demonstrated. A foam sheet 22 made of a soft foam having a closed cell structure is prepared. Moreover, the nonwoven fabric sheet 24 which consists of a nonwoven fabric at least containing a thermoplastic resin fiber is prepared. As the nonwoven fabric sheet 24 of an Example, the nonwoven fabric which consists of a fiber of the core sheath structure mentioned above is used, and it is comprised with two thermoplastic resins from which melting | fusing point differs. The foam sheet 22 and the nonwoven fabric sheet 24 are overlapped to form a laminated sheet 20. Here, the laminated sheet 20 is made of the foam sheet 22 and the nonwoven fabric sheet by a hot melt adhesive such as polyethylene that can be bonded at a heating temperature lower than the melting point of the second thermoplastic resin having a lower melting point in the nonwoven fabric. 24 is bonded in advance. In addition, the foam sheet 22, the nonwoven fabric sheet 24, and the laminated sheet 20 each have flexibility, can be arbitrarily bent, and are easy to handle at the time of bonding or in the process described later.

  As shown in FIG. 4 (a), the two laminated sheets 20 and 20 are held in a flat posture with their ends held by supporters (not shown) and the foam sheet 22 sides facing each other. It supports between a pair of support tools at intervals. Each laminated sheet 20 is heated from both the foam sheet 22 side and the nonwoven fabric sheet 24 side by heating means H such as a heater to a temperature equal to or higher than the melting point of the second thermoplastic resin constituting the fiber sheath in the nonwoven fabric. By this heating step, the sheath portion of the fiber constituting the nonwoven fabric sheet 24 in each laminated sheet 20 is brought into a molten state or a state immediately before melting, while the fiber has a melting point higher than that of the second thermoplastic resin. The solid state of the core made of the thermoplastic resin is maintained. In addition, by performing a heating process, the foam sheet 22 is also softened, and the entire laminated sheet 20 is in a softened state, but by joining the foam sheet 22 and the nonwoven fabric sheet 24 in advance, both sheets 22, Deviation between 24 can be prevented.

  As shown in FIG. 4 (b), the two laminated sheets 20 and 20 heated in the heating step are supported on the molding die 30 with the foam sheet 22 side facing each other with a pair of supports. set. Here, the shaping | molding die 30 clamps the edge part piled up inside the pair of support tool in the two laminated sheets 20 and 20. By performing vacuum forming in which air is sucked from the nonwoven fabric sheet 24 side while being heated by the forming die 30, the two laminated sheets 20 and 20 are separated from each other inside the edge portion sandwiched by the forming die 30, respectively. The nonwoven fabric sheet 24 of the laminated sheet 20 is pressed against the molding surface of the molding die 30 and compression molded. Here, in the said vacuum forming, the nonwoven fabric sheet 24 of each lamination sheet 20 welds the sheath part which makes the outer periphery of the fiber fuse | melted by the said heating process, and a part of fiber is couple | bonded together. On the other hand, the non-woven fabric sheet 24 maintains the solid state without melting the core part that forms the center of the fiber, so that the fibers can be prevented from being completely mixed, and the skeleton can be obtained by melting and solidifying some of the fibers. Is formed and the outer layer portion 18 in which the fiber state is left is formed. Further, in the molding step, the foam sheet 22 of the laminated sheet 20 is pushed outward by performing pressure forming by pressing air between the two laminated sheets 20 and 20 in the mold 30. The inner layer portion 16 is formed by compression molding following the nonwoven fabric sheet 24 formed on the surface. Furthermore, the edge part pinched | interposed into the shaping | molding die 30 in the two laminated sheets 20 and 20 self-bonds the foam sheets 22 and 22, From each laminated sheet 20, it is in the substantially eaves shape mentioned above. At the same time that the shaped divided body 12 is obtained, the edge portions of the two divided bodies 12 and 12 are joined and combined into a cylindrical body. Then, by trimming the end edge portion, the inner layer portion 16 facing the air flow passage 11 is made of a foam, and the outer layer portion 18 facing outward is communicated outwardly between the fibers to absorb water and A cylindrical air-conditioning duct 10 composed of a non-woven fabric leaving a water retaining space is obtained. In addition, since the lamination sheet 20 has the foam sheet 22 which does not have air permeability, vacuum forming and pressure forming are possible.

  Thus, according to the air-conditioning duct 10 of the embodiment, the inner layer portion 16 is made of a foam having a closed cell structure, so that the heat insulation is high, and the entire outer side of the inner layer portion 16 is the outer layer portion 18 made of nonwoven fabric. Since it covers, the heat insulation as a whole is very high, and dew condensation occurring on the outer surface can be suppressed as compared with a duct made of only a foam. And even if dew condensation occurs on the outer surface of the air conditioning duct 10, it is possible to absorb dew condensation in the voids of the outer layer portion 18 constituting the outer surface and retain water in the voids, so that dew condensation can be prevented from dripping from the air conditioning duct 10. In addition, it is possible to avoid problems of peripheral devices due to condensation dripping from the air conditioning duct 10. In addition, the air conditioning duct 10 takes heat away from the surroundings when the condensation held in the outer layer portion 18 evaporates, so that the air conditioning duct 10 is hardly heated. Since the air conditioning duct 10 is excellent in heat insulation, the temperature difference of the temperature-controlled air can be reduced between the inlet and the outlet of the air conditioning duct 10 and the air conditioning efficiency can be improved.

  Since the air-conditioning duct 10 has an airtight structure by the inner layer portion 16 formed of a foam having an independent cell structure, it is possible to suppress a decrease in the flow rate and pressure loss of the temperature-controlled air flowing through the air flow passage 11. In addition, the air conditioning duct 10 exhibits an excellent silencing effect due to sound insulation by the inner layer portion 16 formed of a foam having a closed cell structure and sound absorption by the outer layer portion 18 having a three-dimensional mesh shape. Furthermore, since the air-conditioning duct 10 has a strong skeleton formed by the fibers bonded in the outer layer part 18, the rigidity of the relatively flexible inner layer part 16 can be supplemented to ensure a suitable rigidity capable of maintaining the shape as a whole. . As described above, the entire air conditioning duct 10 is constituted by the multi-layered divided body 12 composed of the inner layer portion 16 and the outer layer portion 18, so that not only the above-described condensation dripping is prevented, but also the heat insulating property, rigidity and sound deadening property are achieved. Can be combined at a high level. The air-conditioning duct 10 is formed by thermoforming a non-woven fabric containing two thermoplastic resins having different melting points to form the outer layer portion 18 so that a part of the fibers is easily bonded while leaving the fiber state by temperature control during manufacturing. be able to. That is, it is possible to form a skeleton having an appropriate rigidity capable of retaining the shape and a void capable of appropriately absorbing and retaining condensation in the outer layer portion 18.

  According to the method for manufacturing the air-conditioning duct 10, since the two divided bodies 12 and 12 can be molded and the divided bodies 12 and 12 can be joined in the same process, the air-conditioning duct 10 is efficiently manufactured. be able to. In addition, in the molding process, by performing pressure forming, the divided body 12 can be pushed from the foam sheet 22 side toward the molding surface, and the inner surface of the inner layer portion 16 facing the air flow passage 11 can be adjusted, and the outer layer portion 18 can be molded more neatly. In addition, since the laminated sheet 20 is pre-bonded with the foam sheet 22 and the nonwoven fabric sheet 24, even if the entire laminated sheet 20 is softened and molded, the foam due to the difference in elongation between the outside and the inside Deviation between the sheet 22 and the nonwoven fabric sheet 24 can be prevented. That is, the divided body 12 can be formed into an arbitrary shape such as the substantially eaves shape described above without breaking the inner layer portion 16 and the outer layer portion 18. Moreover, since the outer layer part 18 is comprised from a nonwoven fabric, since a relative shift | offset | difference is permitted between the fibers which are not welded at the time of thermoforming, and between the fibers in a molten state at the time of thermoforming, it is difficult to wrinkle.

(Experiment)
The air conditioning ducts according to Examples 1 to 4 and the air conditioning ducts according to Comparative Examples 1 to 3 were evaluated with respect to noise, dew condensation, and temperature loss of conditioned air. In addition, the air-conditioning duct of Examples 1-4 and Comparative Examples 1-3 is formed in the same shape and magnitude | size.
(1) The air-conditioning duct of Example 1 is made of a polyethylene foam (melting point: 100 g / m ² ) having a thickness of 5 mm and a 30-fold foamed polyethylene foam (softening point: 100 ° C.) and a 5 mm-thick nonwoven fabric (weight per unit area: 100 g / m ² ). The laminated sheet joined at 135 ° C. is formed in the same manner as the manufacturing method described above to form an inner layer portion having a thickness of 1.5 mm and an outer layer portion having a thickness of 1.5 mm. The nonwoven fabric of Example 1 is composed of a core-sheath structure fiber having a core portion made of polyethylene terephthalate having a melting point of 250 ° C. and a sheath portion made of polyethylene terephthalate having a melting point of 150 ° C. A skin layer made of polypropylene having a thickness of 0.2 mm is joined to the inner peripheral surface of the inner layer portion.
(2) The air-conditioning duct of Example 2 was prepared by using a polyethylene foam (melting point: 100 g / m ² ) of 5 mm thick non-woven foam (softening point 100 ° C.) and 5 mm thick nonwoven fabric (weight per unit area: 100 g / m ² ). The laminated sheet joined at 135 ° C. is formed in the same manner as the manufacturing method described above to form an inner layer portion having a thickness of 1.5 mm and an outer layer portion having a thickness of 1.5 mm. The nonwoven fabric of Example 2 is composed of a core-sheathed fiber having a core part made of polyethylene terephthalate having a melting point of 250 ° C. and a sheath part made of polyethylene terephthalate having a melting point of 150 ° C., and glass fiber. A skin layer made of polypropylene having a thickness of 0.2 mm is joined to the inner peripheral surface of the inner layer portion.
(3) The air-conditioning duct of Example 3 was prepared by combining a polyethylene foam (softening point 100 ° C.) having a thickness of 5 mm and a nonwoven fabric having a thickness of 5 mm (weight per unit area: 500 g / m ² ) with a polyethylene adhesive (melting point). The laminated sheet joined at 135 ° C. is formed in the same manner as the manufacturing method described above to form an inner layer portion having a thickness of 1.5 mm and an outer layer portion having a thickness of 1.5 mm. The nonwoven fabric of Example 3 is composed of a fiber having a core-sheath structure including a core portion made of polyethylene terephthalate having a melting point of 250 ° C. and a sheath portion made of polyethylene terephthalate having a melting point of 150 ° C.
(4) The air conditioning duct of Example 4 was prepared by combining a polyethylene foam (softening point 100 ° C.) having a thickness of 30 mm and a nonwoven fabric having a thickness of 5 mm (weight per unit area: 500 g / m ² ) with a polyethylene adhesive (melting point). The laminated sheet joined at 135 ° C. is formed in the same manner as the manufacturing method described above to form an inner layer portion having a thickness of 1.5 mm and an outer layer portion having a thickness of 1.5 mm. The nonwoven fabric of Example 4 is a mixture of a first fiber made of polyethylene terephthalate having a melting point of 250 ° C. and a second fiber having the same core-sheath structure as that of Example 3. In the nonwoven fabric of Example 4, the first fibers are mixed at a ratio of 75% by weight and the second fibers are mixed at a ratio of 25% by weight.
(5) The air conditioning duct of Comparative Example 1 is a high density polyethylene (HDPE) solid body having a thickness of 1.1 mm.
(6) The air conditioning duct of Comparative Example 2 is obtained by winding a polyurethane foam with a thickness of 3 mm around the outer periphery of a solid body of high density polyethylene (HDPE) with a thickness of 0.6 mm.
(7) The air-conditioning duct of Comparative Example 3 is formed by compression-molding 25 mm foamed polypropylene foam having a thickness of 5 mm to 2.5 mm, and a skin layer made of polypropylene having a thickness of 0.2 mm is bonded to the inner peripheral surface. Has been.

  As for the noise, white noise was passed by a speaker installed in one opening of the air conditioning duct, and the noise was measured by a microphone installed in the other opening of the air conditioning duct. Condensation is the amount of condensation dripped onto a saucer installed under the air conditioning duct by flowing temperature-controlled air at 5 ° C or lower for 1 hour to an air conditioning duct installed in a thermostat set to 40 ° C and 80% humidity. Was measured. The temperature loss of the conditioned air is the same environment as the dew condensation test. Measure the temperature of the conditioned air at the inlet of the air conditioning duct and the temperature of the conditioned air at the outlet every minute. evaluated. The results of these tests are shown in Table 1 below.

  As can be seen from the results of the experiment, it can be confirmed that the air conditioning ducts according to Examples 1 to 4 can prevent dripping of condensation. Moreover, the air-conditioning duct which concerns on Examples 1-4 can also confirm that each parameter | index of noise and the temperature loss of conditioned air is equivalent to a comparative example, or improved from a comparative example.

(Example of change)
The present invention is not limited to the embodiment described above, and can be modified as follows, for example.
(1) In the embodiment, the air conditioning duct is configured by two divided bodies, but the air conditioning duct may be configured by three or more divided bodies.
(2) As the nonwoven fabric, a mixture of the first fiber made of the first thermoplastic resin and the second fiber made of the second thermoplastic resin having a melting point lower than that of the first thermoplastic resin. May be used. In this case, the second thermoplastic resin is heated by heating the nonwoven fabric to a temperature that is equal to or higher than the melting point of the second thermoplastic resin having a relatively low melting point and less than the melting point of the first thermoplastic resin having a relatively high melting point. The outer layer portion may be formed by welding the second fibers made of According to such a modified non-woven fabric, since the welding points between the fibers of the outer layer portion obtained in comparison with the non-woven fabric employed in Example 3 of the experiment can be reduced, the air-conditioning duct of the modified example compared to Example 3 The sound absorbing property and heat insulating property can be improved.

11 air flow passages, 12 divided bodies, 16 inner layer parts, 18 outer layer parts, 20 laminated sheets,
22 Foam sheet, 24 Non-woven sheet

Claims (5)

In the air conditioning duct that is formed into a cylindrical shape by a plurality of divided bodies joined to each other at the edge, and attached to the vehicle,
Of the plurality of divided bodies, the divided body including the lower portion when attached to the vehicle is made of a foam having a closed cell structure, and is composed of an inner layer portion facing the air flow passage and a nonwoven fabric including at least thermoplastic resin fibers. Consisting of an outer layer portion covering the entire outer side of the inner layer portion and facing outward,
The air-conditioning duct is characterized in that the outer layer part is formed so as to bind a part of the fibers by welding the thermoplastic resin fibers and leave a gap communicating between the fibers outward.   The air-conditioning duct according to claim 1, wherein all the divided bodies include the inner layer portion and the outer layer portion.   The air-conditioning duct according to claim 1 or 2, wherein the outer layer portion includes two thermoplastic resins having different melting points and is formed by welding only a thermoplastic resin having a lower melting point. A laminated sheet obtained by laminating a foam sheet made of a foam having a closed cell structure and a nonwoven fabric sheet made of a nonwoven fabric containing at least thermoplastic resin fibers is heated until the thermoplastic resin fibers are melted,
In the state where the two laminated sheets face each other with the foam sheet facing each other, the overlapped edge portion is sandwiched between molds,
Air is sucked from the nonwoven fabric sheet side with the molding die, the nonwoven fabric sheet is pressed against the molding surface of the molding die, and each laminated sheet is vacuum-formed to form a divided body, and the edge part is self-fused. Then, the divided bodies are combined to form a cylinder,
The inner layer portion facing the air flow passage is made of the foam, and the outer layer portion covering the entire outer side of the inner layer portion and facing outward is left in the thermoplastic resin fiber while leaving a void communicating between the fibers. A method for manufacturing an air-conditioning duct, characterized in that it is composed of the nonwoven fabric in which a part of the fibers is bonded by welding.   The method for manufacturing an air conditioning duct according to claim 4, wherein air is pressed between the two laminated sheets during the vacuum forming.

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