JP2016068403A - duct - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a duct that can give sufficient flexibility and low-temperature impact resistance.SOLUTION: Provided is a bendable duct 10 formed by foam blow-molding, and in which a first constituent, at a blending ratio of 30 wt% or more and 80 wt% or less, composed of high density polyethylene (HDPE), and a second constituent, at a blending ratio of 20 wt% or more and 70 wt% or less, composed of low density polyethylene (LDPE) are contained such that the total is 100 wt%, and at least one bent part composed of a plurality of concave portions is included.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a duct, and more particularly to a bendable duct formed by foam blow molding.

  Such a duct is, for example, as disclosed in Patent Document 1 below, an air flow guide that connects an air conditioner unit installed on a vehicle body behind a vehicle interior member of an automobile and an air outlet attached to the vehicle interior member. It is used as a part.

  For this reason, the duct is made of a resin material whose main component is high-density polyethylene (HDPE) or polypropylene (PP), which has high bending rigidity, with an emphasis on assembling with the mating parts. In order to avoid interference with these parts and to increase packing efficiency during transportation, a predetermined portion is formed to be bent by a bent portion formed from a bellows.

  However, since such a duct is made of a material composed of the above resin having high bending rigidity, there is a disadvantage that sufficient flexibility and low temperature impact resistance cannot be obtained.

JP 2009-292442 A

  The present invention has been made based on such circumstances, and an object of the present invention is to provide a duct capable of obtaining sufficient flexibility and low-temperature impact resistance.

The present invention is grasped by the following composition.
(1) The duct according to the first aspect of the present invention is a bendable duct formed by foam blow molding, and is composed of high-density polyethylene (HDPE) having a blending ratio of 30 wt% to 80 wt%. And a second component composed of low-density polyethylene (LDPE) having a blending ratio of 20 wt% or more and 70 wt% or less so that the total amount is 100 wt%, and is composed of a plurality of recesses. It has at least one bent part.

(2) The duct according to the second aspect of the present invention is a bendable duct formed by foam blow molding, and is composed of high density polyethylene (HDPE) having a blending ratio of 50 wt% or more and 70 wt% or less. A second component composed of low density polyethylene (LDPE) having a blending ratio of 20 wt% to 45 wt% and a soft resin having a blend ratio of 30 wt% or less (excluding 0%). The third component to be configured is contained so as to be a total of 100 wt%, and has at least one bent portion constituted by a plurality of concave portions.

(3) In the configuration of (1), the first component may have a blending ratio of 50 wt% to 70 wt%, and the second component may have a blend ratio of 30 wt% to 50 wt%.

(4) In any one of the constitutions (1) to (3), the bent portion has a first concave portion on the first side and a second side opposite to the first side on the wall surface. A plurality of second recesses, and the second recesses may have a smaller pitch and depth than the first recesses.

  ADVANTAGE OF THE INVENTION According to this invention, the duct which can obtain sufficient flexibility and low temperature impact resistance can be provided.

It is the schematic diagram which showed the embodiment of the duct of this invention. (A) is the perspective view which showed the vicinity of the bending part of the duct of this invention, (b) is sectional drawing in the bb line of (a). It is the perspective view which bent the duct of this invention in the part of the bending part. (A) thru | or (d) are typical process drawings which show one Embodiment of the manufacturing method of the duct of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. Note that the same number is assigned to the same element throughout the description of the embodiment.

(Embodiment 1)
FIG. 1 shows an embodiment of a duct according to the present invention. For example, a duct disposed between a vehicle body and a vehicle interior member is taken as an example. As shown in FIG. 1, an air conditioner unit 2 is installed on a vehicle body (not shown) on the back side of a vehicle interior member 1 of an automobile, and is a part of the vehicle interior member 1 and is relatively far from the air conditioner unit 2. An air outlet 3 is formed at the position. A duct 10 that connects the air conditioner unit 2 and the air outlet 3 is disposed between the vehicle body and the vehicle interior member 1. The duct 10 functions as an air circulation guide unit that guides air from the air conditioner unit 2 to the air outlet 3 as indicated by a dotted line A in the figure.

  The duct 10 has, for example, a circular cylindrical shape, and has, for example, two bent portions between the air conditioner unit 2 and the air outlet 3 in order to avoid interference with other parts (not shown). Yes. As a result, the duct includes a straight portion and bendable bend portions B1 and B2 that are continuous with the straight portion. The bent portion B1 on the air conditioner unit 2 side is bent, for example, approximately 90 ° in the clockwise direction, and the bent portion B2 on the air outlet 3 side is bent, for example, approximately 90 ° in the counterclockwise direction. Needless to say, the duct 10 is not limited in its cross-sectional shape, the number of bent portions, the bending direction, or the bending angle.

  The duct 10 is made of a resin material formed by foam blow molding. Foam blow molding is a technique in which a resin material to which a foaming agent is added is blow molded, and the wall surface of the duct 10 can be foamed. As described above, the duct 10 made of the resin material to which the foaming agent is added can improve the bendability at the bent portions B1 and B2 by adjusting the foamed state.

  And the duct 10 contains in the material the 1st component comprised from hard resin, the 2nd component comprised from soft resin, and the 3rd component as an addition resin added as needed. . High density polyethylene (HDPE: High Density Polyethylene) can be suitably used as the first component, and low density polyethylene (LDPE) can be suitably used as the second component.

  Here, when the third component is not included, the first component preferably has a blending ratio of 30 wt% to 80 wt%, and the second component has a blend ratio of 20 wt% to 70 wt% in total of 100 wt%. Have as. More preferably, the first component has a blending ratio of 50 wt% or more and 70 wt% or less, and the second component has a blending ratio of 30 wt% or more and 50 wt% or less so that the total is 100 wt%.

  About these compounding ratios, if the significance is explained with the low density polyethylene (LDPE) as the second component, the low density polyethylene (LDPE) as the second component is set to 20 wt% or more. This is because sufficient flexibility cannot be obtained, and if the bent portion is bent, cracking occurs, or a so-called whitening phenomenon occurs, and further, inconvenience that sufficient foaming cannot be obtained occurs. If it is 20 wt% or more, these inconveniences are within an allowable range, and if it is 30 wt% or more, these inconveniences can be surely solved.

  Moreover, the reason why the low density polyethylene (LDPE), which is the second component, is 70 wt% or less, if it exceeds that, the softness becomes excessive, the workability becomes worse when attaching the duct to the automobile, and the bent portion This is because the straight portions other than B1 and B2 are also easily bent, so that the inconvenience that the bent portions B1 and B2 do not function is caused. If it is 70 wt% or less, these inconveniences are within an allowable range, and if it is 50 wt% or less, these inconveniences can be surely eliminated.

  From this fact, by setting the blending ratio of the low density polyethylene (LDPE) as the second component to 20 wt% or more and 70 wt% or less with respect to the high density polyethylene (HDPE) as the first component, sufficient flexibility and resistance Low temperature impact properties can be obtained. If the blending ratio of the second component is 30 wt% or more and 50 wt% or less, further sufficient flexibility and low temperature impact resistance can be obtained.

  Next, a case where the third component is included will be described. Even if it is a bit with an automobile, it is required to meet various conditions such as cold region specifications, dry desert region specifications, and hot and humid tropical specifications. The same applies to the duct 10. Therefore, in order to secure the duct 10 having the optimum quality under the use conditions, as a soft resin other than high density polyethylene (HDPE) and low density polyethylene (LDPE), for example, impact resistance, particularly impact resistance at low temperature. In order to improve this, an elastomer component can be added. Furthermore, it is preferable to add an olefin elastomer or a styrene elastomer from the viewpoint of compatibility with the first component and the second component.

  In this case, the blending ratio of the added resin is preferably 30 wt% or less. It is because it will become difficult to foam the duct 10 as desired when the mixture ratio exceeds 30 wt%. Accordingly, the blend ratio of the first component, the second component, and the third component when the third component is included is preferably a blend ratio of 50 wt% or more and 70 wt% or less for the first component, and 20 wt% or more for the second component. The third component has a blending ratio of 45 wt% or less, and the third component has a blending ratio of 30 wt% or less (not including 0%) so that the total is 100 wt%.

  FIG. 2A shows a part of the duct 10 and shows the vicinity of the bent portion B2 (see FIG. 1). FIG. 2B is a cross-sectional view taken along the line bb in FIG. As shown in FIGS. 2A and 2B, on the wall surface (circumferential side surface) of the duct 10, the first recess 11 on the first side (upper side in the figure) and the opposite side of the first side. A plurality of second recesses 12 are formed on the second side (lower side in the figure). The first concave portion 11 is formed along the circumferential direction on the first side, and the second concave portion 12 is formed along the circumferential direction on the second side. The first recess 11 has a relatively large depth D and is formed to have a relatively wide width along the axial direction of the duct 10. Further, the second recess 12 has a relatively small depth d, and a plurality of the second recesses 12 are formed along the axial direction of the duct 10, each of which is formed to have a relatively narrow width. As a result, the second recesses 12 are formed with a smaller pitch and depth than the first recesses 11.

  As shown in FIG. 3, the duct 10 formed in this way has a trough (concave) on the first side (side on which the first recess 11 is formed) in the bent portion B <b> 1. 2 is easier to bend in the direction of arrow B so that the side on which the concave portion 12 is formed becomes a mountain (convex). Thus, when the bending direction of the duct is determined in advance, the first concave portion 11 and the second concave portion 12 having a simple configuration as compared with, for example, the bellows structure can be formed. There is an effect that can be simplified. In the other bent portion B1 of the duct 10, as shown in FIG. 1, the first concave portion 11 is formed on the side that becomes the valley (concave), and the second concave portion 12 is formed on the side that becomes the peak (convex). It has come to be.

  FIGS. 4A to 4D are schematic process diagrams showing an embodiment of a method for manufacturing the duct 10 of the present invention. First, as shown in FIG. 4A, the molding apparatus 20 includes a molten resin extrusion apparatus 21 and split molds 22A and 22B for clamping a pair of thermoplastic resin sheets P1 and P2 from the extrusion apparatus 21. And a mold clamping device 22 having The extruding device 21 feeds the melted and kneaded resin in a cylinder (not shown) into the pair of T dies 21T, and then continues the pair of thermoplastic resin sheets P1 and P2 downward through the die slits of each T die 21T. To extrude. These thermoplastic resin sheets P1 and P2 contain a foaming agent in advance.

The mold clamping device 22 includes split molds 22A and 22B arranged with a pair of thermoplastic resin sheets P1 and P2 suspended downward. The split molds 22A and 22B have cavities 23A and 23B formed on their opposing surfaces. The surface of each cavity 23A, 23B has unevenness according to the surface shape of the duct 10 formed by the molten thermoplastic resin sheets P1, P2. In FIG. 4A, the surfaces of the cavities 23A and 23B of the divided molds 22A and 22B are arcuate, and the shape of the first recess 11 (see FIG. 1) of the duct 10 is formed in one divided mold 22A. A first convex portion 24A corresponding to the second convex portion 24B corresponding to the shape of the second concave portion 12 (see FIG. 1) of the duct 10 is formed on the other split mold 22B. The split molds 22A and 22B have air intake holes 26A and 26B communicating with the cavities 23A and 23B, respectively.

  In the molding apparatus 20 having such a configuration, first, as shown in FIG. 4A, each of the divided molds 22A and 22B is disposed at a position that is the most spaced apart, and between these divided molds 22A and 22B. The thermoplastic resin sheets P1 and P2 from the respective T dies 21T are dropped close to each other. Next, as shown in FIG. 4B, each of the divided molds 22A and 22B is moved in a direction in which the distance is reduced (α direction in the figure), and one of the divided molds 22A is outside the area of the cavity 23A. The surface comes into contact with the thermoplastic resin sheet P1, and the other split mold 22B comes into contact with the thermoplastic resin sheet P2 on the surface outside the area of the cavity 23B.

  Further, as shown in FIG. 4 (c), the inside of the cavity 23A of the split mold 22A is depressurized through the air intake hole 26A, thereby adsorbing the thermoplastic resin sheet P1 to the surface of the cavity 23A, and at the same time, the split mold The pressure inside the cavity 23B of the mold 22B is reduced through the air intake holes 26B, thereby adsorbing the thermoplastic resin sheet P2 on the surface of the cavity 23B. Thereby, the half shape along the axial direction of the duct 10 is created by the split mold 22A, and the other half shape is created by the split mold 22B.

  Then, as shown in FIG. 4D, each of the split molds 22A and 22B is moved in a direction to further reduce the distance (α ′ direction in the figure), and the thermoplasticity is formed on the surface outside the area of each cavity 23A and 23B. The resin sheets P1 and P2 are sandwiched and bonded. As a result, a duct having the parting line PL is formed at the boundary between the divided molds 22A and 22B. In FIG. 4, (c) and (d) show the mold clamping device 22 and omit the extrusion device 21.

(Embodiment 2)
In the first embodiment described above, the bent portions B1 and B2 of the duct 10 have, as shown in the figure, the first concave portion 11 on the first side and the second opposite to the first side on the wall surface. A plurality of second recesses 12 are provided on the side. However, the present invention is not limited to this, and it is needless to say that a bellows shape in which a plurality of concave and convex portions formed annularly in the circumferential direction may be provided in the axial direction. This is because the bent portions B1 and B2 of the duct 10 only need to be formed to be bendable at the bent portions B1 and B2.

(Embodiment 3)
In the above-described embodiment, the duct 10 disposed between the vehicle body and the vehicle interior member is described. However, the present invention is not limited to this, and it goes without saying that the duct of the present invention can be used in fields other than automobiles.

  The material of the duct 10 will be described below using examples and comparative examples.

  Grade B470 high density polyethylene (HDPE) was used as the first component, grade M1820 low density polyethylene (LDPE) as the second component, and olefin elastomer as the third component. Table 1 shows the test results when the third component is not included, and Table 2 shows the test results when the third component is included. The evaluation was indicated by “◎: excellent”, “◯: good”, and “×: impossible”.

  As shown in Table 1, in the flexibility, in Comparative Example 1, cracking and whitening occurred at the time of bending, and in Comparative Example 2, the workability was remarkably lowered easily at other than the bent portion. Moreover, regarding low temperature impact resistance, Comparative Example 1 was insufficient, and Comparative Example 2 did not cause cracks.

  As shown in Table 2, in foamability, in Comparative Example 4, the foaming ratio was less than 1.5, and desired foaming was not obtained. In Comparative Example 3, no difficulty was observed in foamability, but sufficient results were not obtained in flexibility and low-temperature impact resistance.

  As mentioned above, although this invention was demonstrated using embodiment, it cannot be overemphasized that the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments. Further, it is apparent from the description of the scope of claims that embodiments with such changes or improvements can also be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Vehicle interior member 2 Air conditioner unit 3 Air outlet 10 Duct 11 1st recessed part 12 2nd recessed part 20 Molding apparatus 21 Extrusion apparatus 21T T die 22 Clamping apparatus 22A, 22B Split mold 23A, 23B Cavity 24A 1st convex Portion 24B second convex portions B1, B2 bent portions P1, P2 thermoplastic resin

Claims (4)

A bendable duct formed by foam blow molding,
A first component composed of high density polyethylene (HDPE) having a blending ratio of 30 wt% to 80 wt%;
A second component composed of low-density polyethylene (LDPE) having a blending ratio of 20 wt% or more and 70 wt% or less, and a total content of 100 wt%,
A duct having at least one bent portion composed of a plurality of concave portions. A bendable duct formed by foam blow molding,
A first component composed of high density polyethylene (HDPE) having a blending ratio of 50 wt% or more and 70 wt% or less;
A second component composed of low density polyethylene (LDPE) having a blending ratio of 20 wt% or more and 45 wt% or less;
Containing a third component composed of a soft resin at a blending ratio of 30 wt% or less (not including 0%) so as to be a total of 100 wt%,
A duct having at least one bent portion composed of a plurality of concave portions.   The duct according to claim 1, wherein the first component has a blending ratio of 50 wt% or more and 70 wt% or less, and the second component has a blending ratio of 30 wt% or more and 50 wt% or less. The bent portion is on the wall surface,
A first recess on a first side;
A plurality of second recesses on a second side opposite to the first side;
The duct according to any one of claims 1 to 3, wherein the second recess has a smaller pitch and depth than the first recess.

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