Resin molded product and manufacturing method thereof

Abstract

To facilitate separation of parts of a resin molded product.SOLUTION: A bent duct for a vehicle 10 as a resin molded product includes a body part 12 formed of first resin and a seal part 14 formed of second resin in a cyclic manner to surround a periphery of the body part 12 onto an outer surface of the body part 12. The first resin and the second resin are not fused with each other, and as for the second resin, one kind having a mold shrinkage factor larger than that of the first resin is used.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resin molded product and a method for manufacturing a resin molded product. [Background technology]

[0002] An example of a resin molded product is a vent duct that includes a frame body made of polypropylene and a sealing member made of TPO that is joined to the periphery of the frame body (see, for example, Patent Document 1). In the vent duct of Patent Document 1, the sealing member is joined to the frame body by molding the sealing member in a mold in which the frame body is placed as an insert. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-34128 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for promoting the recycling of resin molded products. The above-mentioned vent duct is made of multiple resins, so it cannot be recycled as is, and it is necessary to remove the sealing member from the frame. However, since the frame and the sealing member are joined in the vent duct, it is difficult to separate the frame and the sealing member.

[0005] The present invention has been proposed in consideration of the above-mentioned problems associated with the conventional technology, and aims to provide a resin molded product in which the main body portion and the sealing portion can be easily separated, and a manufacturing method thereof. [Means for solving the problem]

[0006] A first aspect of the resin molded product according to the present invention is a main body portion formed of a first resin; a seal portion formed in an annular shape on an outer surface of the main body portion and made of a second resin so as to surround the main body portion; The first resin and the second resin are not fused to each other, and the second resin has a molding shrinkage rate larger than that of the first resin.

[0007] A second aspect of the resin molded product according to the present invention is the resin molded product according to the first aspect, a first wall portion protruding from an outer surface of the main body portion; and a second wall portion protruding from the main body portion and spaced apart from the first wall portion in a direction intersecting the circumference, the first wall portion protrudes from the outer surface of the main body portion more than the second wall portion; The seal portion may extend from between the first wall portion and the second wall portion toward the second wall portion.

[0008] A third aspect of the resin molded product according to the present invention is the resin molded product according to the second aspect of the present invention, The seal portion may have a contact portion that contacts an end surface of the first wall portion.

[0009] A fourth aspect of the resin molded product according to the present invention is the resin molded product according to the second or third aspect, The housing may include a first protrusion that protrudes from the first wall portion toward the second wall portion and fits into the seal portion.

[0010] A fifth aspect of the resin molded product according to the present invention is any one of the first, second, third, and fourth aspects of the resin molded product, The first resin may be polypropylene and the second resin may be a polyester elastomer.

[0011] A sixth aspect of the resin molded product according to the present invention is any one of the first, second, third, fourth, and fifth aspects of the resin molded product, It may be a vehicle vent duct or a vehicle seal plate.

[0012] A first aspect of the method for producing a resin molded product according to the present invention is to After forming the main body by injection molding the first resin, The gist of the method is that a second resin having a molding shrinkage rate greater than that of the first resin and which does not fuse to the first resin is injection molded in a cavity in which the main body portion is set, to form an annular seal portion on the outer surface of the main body portion that surrounds the main body portion. Effect of the Invention

[0013] According to the resin molded product of the present invention, the main body portion and the seal portion can be easily separated. According to the method for manufacturing a resin molded product of the present invention, it is possible to obtain a resin molded product in which the main body portion and the seal portion can be easily separated. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view showing a vehicle vent duct according to a first embodiment, as viewed from the front side. FIG. [Diagram 2] FIG. 2 is a rear view showing the vehicle vent duct according to the first embodiment. [Diagram 3] 1 is a vertical cross-sectional view showing a vehicle vent duct according to a first embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Diagram 5] 3 is a cross-sectional view of a main part taken along line BB in Fig. 2. Note that a vehicle body locking portion and a vehicle body abutment portion are omitted from the illustration. [Figure 6] 3A to 3C are explanatory views showing a manufacturing process of the vehicle vent duct according to the first embodiment. [Figure 7] 3A to 3C are explanatory views showing a manufacturing process of the vehicle vent duct according to the first embodiment. [Figure 8] FIG. 11 is a perspective view of a vehicle seal plate according to a second embodiment, as viewed from the rear side. [Figure 9] FIG. 11 is an explanatory view showing a state in which a vehicle seal plate according to a second embodiment is attached to a vehicle body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, the resin molded product and the manufacturing method of the resin molded product according to the present invention will be described below with reference to the accompanying drawings, using preferred examples. Note that the embodiments and drawings described below are merely examples of the present invention, and are not intended to limit the present invention to these configurations, and may be modified as appropriate without departing from the scope of the present invention. EXAMPLES

[0016] (First embodiment) In the first embodiment, as an example of the resin molded product of the present invention, a vehicle vent duct 10 is exemplified, which is attached to a vehicle body 50 (FIG. 3) of a vehicle such as an automobile and serves as an exhaust port for ventilating the air in the vehicle cabin. As shown in FIGS. 1 and 2, the vehicle vent duct 10 includes a cylindrical main body 12 having an air passage 12a, and a seal portion 14 formed on the outer surface of the main body 12 so as to surround the main body 12. The vehicle vent duct 10 also includes an opening / closing valve 16 for opening and closing the air passage 12a of the main body 12. The main body 12 is an injection molded product formed of a first resin. The seal portion 14 is an injection molded product formed of a second resin different from the first resin constituting the main body 12. The vehicle vent duct 10 is a two-color molded product in which the main body 12 and the seal portion 14 made of different resins are combined.

[0017] As shown in Fig. 1 and Fig. 2, the main body 12 is cylindrical in shape, with the upper, lower, left and right passage walls 18 forming an air passage 12a with a horizontally elongated, generally rectangular opening. The main body 12 also has a plurality of plate-shaped support parts 20 extending vertically in the air passage 12a (see Fig. 2). The support parts 20 are arranged spaced apart in the horizontal direction. The main body 12 has a receiving surface formed by the side passage walls 18, the lower passage wall 18 and the surfaces of the support parts 20 facing the outside of the vehicle, and receives the on-off valve 16 in a closed position. The receiving surface of the main body 12 is inclined toward the outside of the vehicle as it extends downward (see Fig. 3).

[0018] As shown in Fig. 3, the main body 12 includes a first wall 22 protruding from the outer surface of the passage wall 18, and a second wall 24 protruding from the outer surface of the passage wall 18. The first wall 22 is formed on the outer edge of the passage wall 18 on the vehicle outer side, over the entire circumference of the outer surface of the main body 12. The second wall 24 is formed on the outer surface of the main body 12, over the entire circumference, away from the first wall 22 towards the vehicle inner side (in a direction intersecting the circumference of the main body 12). The first wall 22 protrudes farther from the outer surface of the main body 12 than the second wall 24, and the protruding end of the first wall 22 is located outside the protruding end of the second wall 24.

[0019] 5, the main body 12 has a first protrusion 26 that protrudes from the first wall 22 toward the second wall 24 and fits into the seal portion 14. The protrusion dimension of the first protrusion 26 from the first wall 22 is smaller than the distance between the first wall 22 and the second wall 24, and the first protrusion 26 is spaced apart from the second wall 24. The protrusion dimension of the first protrusion 26 is preferably set to half or less of the distance between the first wall 22 and the second wall 24. A plurality of first protrusions 26 are provided spaced apart from each other in the circumferential direction of the main body 12.

[0020] As shown in FIG. 5, the main body 12 includes a second protruding portion 28 that protrudes from the second wall 24 toward the first wall 22 and fits into the seal portion 14. The protruding dimension of the second protruding portion 28 from the second wall 24 is smaller than the distance between the first wall 22 and the second wall 24, and the second protruding portion 28 is spaced apart from the first wall 22. It is preferable that the protruding dimension of the second protruding portion 28 is set to be equal to or less than half the distance between the first wall 22 and the second wall 24. The second protruding portion 28 is disposed so as to be shifted in the circumferential direction relative to the first protruding portion 26. A plurality of second protruding portions 28 are provided at intervals in the circumferential direction of the main body 12, and in the first embodiment, the first protruding portions 26 and the second protruding portions 28 are disposed alternately in the circumferential direction.

[0021] 2 and 3, the main body 12 has a vehicle body locking portion 30 formed on the vehicle inner side of the second wall portion 24. The vehicle body locking portion 30 is provided on each of the upper and lower passage wall portions 18, and is formed in a hook shape that protrudes from the outer surface of the main body 12 and then bends toward the outside of the vehicle. The vehicle body locking portion 30 hooks onto the inner surface of the vehicle body 50 when the main body 12 is fitted into the mounting opening 50a of the vehicle body 50.

[0022] 2 and 3, the main body 12 has a plate-shaped vehicle body contact portion 32 that protrudes from the outer surface of the main body 12. The vehicle body contact portion 32 is provided on each of the upper and lower passage wall portions 18. When the main body 12 is inserted into the mounting opening 50a, the vehicle body contact portion 32 fits into the mounting opening 50a of the vehicle body 50.

[0023] The main body 12 is a hard resin member in which the passage wall 18, the support portion 20, the first wall 22, the second wall 24, the first protruding portion 26, the second protruding portion 28, the vehicle body locking portion 30, and the vehicle body abutting portion 32 are integrally formed. Examples of the first resin constituting the main body 12 include thermoplastic resins such as olefin resins such as polypropylene (PP) and polyethylene (PE). Olefin resins such as polypropylene (PP) and polyethylene (PE) are non-polar resins with no or very small charge imbalance in the molecular structure, and are hardly fused to resins of different types.

[0024] 4, the seal portion 14 is formed so as to abut against the outer surfaces of the upper, lower, left and right passage wall portions 18 of the main body portion 12 and surround the entire periphery of the upper, lower, left and right passage wall portions 18 of the main body portion 12. The seal portion 14 is not joined to the main body portion 12 by fusion, welding, adhesion, or the like, but is pressed against the outer surfaces of the main body portion 14 by its own molding shrinkage acting in a circumferential shrinking direction. The seal portion 14 should have flexibility to deform when it abuts against the vehicle body 50 and elasticity to return to an appropriate state after deformation.

[0025] As shown in Fig. 3, the seal portion 14 extends from between the first wall portion 22 and the second wall portion 24 toward the second wall portion 24. More specifically, the seal portion 14 is fin-shaped and curves toward the inside of the vehicle as it extends outward from between the first wall portion 22 and the second wall portion 24. In addition, the seal portion 14 has a tapered shape that becomes thinner from the main body portion 12 side toward the tip on the outside of the second wall portion 24. The seal portion 14 has an abutment portion 14a that abuts against the end face of the first wall portion 22.

[0026] The second resin constituting the seal portion 14 is a resin that does not fuse with the first resin. As described above, since the first resin is a non-polar resin, the second resin is a non-polar or polar resin different from the first resin. Examples of the second resin include thermoplastic elastomers such as polystyrene-based (TPS), olefin-based (TPO), polyvinyl chloride-based (TPVC), polyurethane-based (TPU), polyester-based (TPEE or TPC), and polyamide-based (TPAE). Here, the thermoplastic elastomer used is one that contains a type of resin different from the first resin in the hard segment. For example, if the first resin is polypropylene, a thermoplastic elastomer other than an olefin-based elastomer may be used.

[0027] The second resin constituting the seal portion 14 is a resin having a larger mold shrinkage rate than the first resin. Here, the second resin is preferably a thermoplastic elastomer containing a crystalline resin having a larger mold shrinkage rate than a non-crystalline resin as a hard segment, such as an olefin-based (TPO), polyester-based (TPEE or TPC), or polyamide-based (TPAE) thermoplastic elastomer. Among these, a polyester-based (TPEE or TPC) thermoplastic elastomer is preferable because it has a large mold shrinkage rate. For example, specific combinations of the first resin and the second resin include a combination of polypropylene as the first resin and a polyester-based thermoplastic elastomer as the second resin, and a combination of polyethylene as the first resin and a polyester-based thermoplastic elastomer as the second resin. Among these, a combination of the first resin and the second resin is preferably polypropylene as the first resin and a polyester-based thermoplastic elastomer as the second resin, from the viewpoint of preventing the main body 12 and the seal portion 14 from fusing to each other and allowing the seal portion 14 to appropriately undergo mold shrinkage.

[0028] The on-off valve 16 is a thin plate-like body, and is made of a flexible material such as an elastomer such as an olefin-based elastomer (TPO) or a styrene-based elastomer, or a rubber-based material such as ethylene-propylene-diene rubber (EPDM). The on-off valve 16 also has elasticity that tends to return to its original state when bent. As shown in FIG. 3, the upper end of the on-off valve 16 is fixed to a portion of the main body 12 that protrudes downward from the upper passage wall 18. The on-off valve 16 is designed so that its own weight acts toward the closed position on the main body portion that hangs from the upper passage wall 18 to the ventilation passage 12a, simply by fixing the upper end of the on-off valve 16 to the main body 12. The on-off valve 16 may be attached to the main body 12 later, or may be molded with the second resin when the seal portion 14 is molded.

[0029] The on-off valve 16 is suspended from the air passage 12a, and the displacement of the on-off valve 16 toward the inside of the vehicle due to its own weight is restricted by the receiving surface of the main body 12, so that the on-off valve 16 assumes a closed position that blocks the air passage 12a (see solid line in FIG. 3). The vehicle vent duct 10 blocks the air passage 12a with the on-off valve 16 in the closed position due to its own weight, preventing the intrusion of foreign matter such as dust and water from the outside of the vehicle. In addition, the vehicle vent duct 10 opens the air passage 12a when the on-off valve 16 is displaced toward the outside of the vehicle due to the pressure difference between the inside and outside of the vehicle when the door is closed, for example, and allows air to flow from the vehicle interior to the outside (see two-dot chain line in FIG. 3).

[0030] As shown in Fig. 3, the vehicle vent duct 10 is attached by fitting into a mounting opening 50a formed in a vehicle body 50. The vehicle vent duct 10 is covered on the outside by a vehicle exterior member (not shown) such as a rear bumper, and is hidden from the outside of the vehicle. The upstream side of the air passage 12a of the vehicle vent duct 10 is connected to a vehicle interior space provided inside the vehicle body 50, and the downstream side of the air passage 12a is connected to the outside of the vehicle, and the air in the vehicle interior can be exhausted to the outside of the vehicle through the air passage 12a.

[0031] Next, a manufacturing method of the vehicle vent duct 10 of the first embodiment will be described. As shown in Fig. 6, a first cavity 41 formed between a first mold 40 and a second mold 42 is filled with a first resin while applying pressure, and the main body 12 is injection molded. The first mold 40 and the second mold 42 are opened, leaving the main body 12 in the first mold 40. The second mold 42 has a second slide mold 42a in a portion corresponding to the first wall 22 and the second wall 24 that is movable in a direction intersecting the mold opening direction.

[0032] As shown in FIG. 7, while the main body 12 is held by the first mold 40, the second mold 42 is replaced by the third mold 44, and the second cavity 43 formed between the first mold 40, the main body 12 held by the first mold 40, and the third mold 44 is filled with the second resin while applying pressure, thereby injection-molding the seal portion 14. The first mold 40 and the third mold 44 are opened, and the main body 12 having the seal portion 14 formed on the outer surface is taken out. The third mold 44 has a third slide mold 44a in a portion corresponding to the seal portion 14, which is movable in a direction intersecting with the mold opening direction. Then, the opening / closing valve 16 molded separately is attached to the main body 12, thereby obtaining the vehicle vent duct 10. In this way, in the first embodiment, the main body 12 and the seal portion 14 are manufactured by two-color molding using the first mold 40 in common.

[0033] In the above-mentioned manufacturing method, first, a first resin is injection molded in a first cavity 41 to form the main body 12. Then, in a second cavity 43 in which the main body 12 is set, a second resin having a molding shrinkage rate larger than that of the first resin and not fused to the first resin is injection molded to form an annular seal portion 14 surrounding the main body 12 on the outer surface of the main body 12.

[0034] In the vehicle vent duct 10 of the first embodiment, the main body 12 and the seal portion 14 are not joined because the main body 12 and the seal portion 14 are made of resins that do not fuse to each other. In the vehicle vent duct 10, the second resin constituting the seal portion 14 has a molding shrinkage rate greater than that of the first resin constituting the main body 12, and the seal portion 14 is formed surrounding the main body 12. Therefore, the seal portion 14 itself shrinks and becomes smaller, so that it is held in a state pressed against the outer surface of the main body 12. Note that since the molding shrinkage rate of the seal portion 14 is greater than that of the main body 12, even if the main body 12 shrinks, the seal portion 14 shrinks beyond that, so that the seal portion 14 is held on the outer surface of the main body 12. In this way, the vehicle vent duct 10 does not join the main body 12 and the seal portion 14, but the seal portion 14 can be attached to the outer surface of the main body 12.

[0035] In the vehicle vent duct 10 of the first embodiment, the main body 12 and the seal portion 14 are made of different resins that do not fuse to each other, and therefore the main body 12 and the seal portion 14 are not joined. This allows the vehicle vent duct 10 to easily remove the seal portion 14 from the main body 12, for example, by cutting and opening the seal portion 14. Therefore, when disposing of the vehicle vent duct 10, the main body 12 made of the first resin and the seal portion 14 made of the second resin can be easily separated.

[0036] The seal portion 14 is disposed between a first wall portion 22 protruding from the outer surface of the main body portion 12 and a second wall portion 24 protruding from the main body portion 12, spaced from the first wall portion 22 in a direction intersecting the circumference of the main body portion 12. This makes it possible to prevent the seal portion 14 from shifting in a direction intersecting the circumference of the main body portion 12 by the first wall portion 22 and the second wall portion 24, and to appropriately fix the seal portion 14 in position without joining it to the main body portion 12. In addition, the seal portion 14 extends toward the second wall portion 24 from between the first wall portion 22 and the second wall portion 24, but the first wall portion 22 protrudes farther from the outer surface of the main body portion 12 than the second wall portion 24. Therefore, when the seal portion 14 extending toward the second wall portion 24 abuts against the vehicle body 50, the seal portion 14 can be prevented from shifting by the first wall portion 22. Furthermore, since the seal portion 14 has an abutment portion 14a that abuts against the end face of the first wall portion 22, when the seal portion 14 extending toward the second wall portion 24 abuts against the vehicle body 50, the seal portion 14 can be prevented from shifting due to the engagement between the end face of the first wall portion 22 and the abutment portion 14a.

[0037] By providing the first protruding portion 26 that protrudes from the first wall portion 22 toward the second wall portion 24 and fits into the seal portion 14, the first protruding portion 26 that fits into the seal portion 14 can prevent the seal portion 14 from moving in the circumferential direction. Also, by providing the second protruding portion 28 that protrudes from the second wall portion 24 toward the first wall portion 22 and fits into the seal portion 14, the second protruding portion 28 that fits into the seal portion 14 can prevent the seal portion 14 from moving in the circumferential direction. In particular, by arranging the first protruding portion 26 and the second protruding portion 28 alternately in the circumferential direction, the seal portion 14 can be prevented from loosening.

[0038] Second embodiment An example of the resin molded product of the present invention may be a vehicle seal plate 60 attached to a vehicle body 50 of a vehicle such as an automobile, as in the second embodiment shown in Figs. 8 and 9. The vehicle seal plate 60 of the second embodiment closes the gap between a pillar and a fender of a vehicle, and is also called a fender insulator. The vehicle seal plate 60 includes a plate-shaped main body 12 and a seal portion 14 formed on the outer surface of the main body 12 so as to surround the main body 12. The main body 12 is an injection molded product formed of a first resin. The seal portion 14 is an injection molded product formed of a second resin different from the first resin constituting the main body 12. The vehicle seal plate 60 is a two-color molded product in which the main body 12 and the seal portion 14 made of different resins are combined. The vehicle seal plate 60 of the second embodiment differs from the first embodiment in that the main body 12 is plate-shaped, but other configurations and manufacturing methods are similar to those of the first embodiment, so configurations having the same functions are given the same reference numerals as in the first embodiment and descriptions thereof are omitted. The vehicle seal plate 60 of the second embodiment achieves the same effects as the first embodiment.

[0039] (Example of change) The present invention is not limited to the above, and may be, for example, as follows: Note that the present invention is not limited to the specific descriptions of the embodiment and the following modified examples. (1) The resin molded product is not limited to a vehicle vent duct or a vehicle seal plate, but may be applied to other components that require sealing between the object to which it is attached, such as a door cover or a service hole cover. (2) The first wall portion and the second wall portion do not necessarily have to be formed continuously around the entire circumference of the main body portion, but may be formed on a partial range of the outer surface of the main body portion. (3) The resin molded product may be produced by insert molding, in which the main body is injection molded in a first mold, the main body is removed from the first mold, and the main body is set in a second mold while the seal portion is injection molded in the second mold. [Explanation of symbols]

[0040] 10 Vehicle vent duct, 12 Main body, 14 Seal portion, 14a Contact portion, 22 first wall portion, 24 second wall portion, 26 first protrusion portion, 60 vehicle seal plate

Claims

1. a main body portion formed of a first resin; a seal portion formed in an annular shape on an outer surface of the main body portion and made of a second resin so as to surround the main body portion, The first resin and the second resin are not fused to each other, and the second resin has a molding shrinkage rate larger than that of the first resin.

2. a first wall portion protruding from an outer surface of the main body portion; and a second wall portion protruding from the main body portion and spaced apart from the first wall portion in a direction intersecting the circumference, the first wall portion protrudes from the outer surface of the main body portion more than the second wall portion; The resin molded product according to claim 1 , wherein the seal portion extends from between the first wall portion and the second wall portion toward the second wall portion.

3. The resin molded product according to claim 2 , wherein the seal portion has an abutment portion that abuts against an end surface of the first wall portion.

4. The resin molded product according to claim 2 , further comprising a first protruding portion that protrudes from the first wall portion toward the second wall portion and fits into the seal portion.

5. 2. The resin molded product according to claim 1, wherein the first resin is polypropylene and the second resin is a polyester elastomer.

6. 2. The resin molded product according to claim 1, which is a vent duct for a vehicle or a seal plate for a vehicle.

7. After forming the main body by injection molding the first resin, A method for manufacturing a resin molded product, comprising: in a cavity in which the main body portion is set, injection molding a second resin having a molding shrinkage rate greater than that of the first resin and which does not fuse to the first resin, to form an annular seal portion on the outer surface of the main body portion that circumscribes the main body portion.

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