JP4651243B2 - Molding method of resin molded product with foamed resin sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for molding a resin molded product with a foamed resin sheet, and more particularly, to a method for molding a resin molded product with a foamed resin sheet by joining the foamed resin sheet to a resin molded part molded into a required shape. Is.
[0002]
[Prior art]
For example, an air conditioner case that constitutes an in-vehicle air conditioner unit that is used for air conditioning in a passenger car or the like often employs a synthetic resin molded product in which a resin material such as polypropylene (PP) is injection-molded into a box shape. In addition to the air conditioner case of the air conditioner unit described above, various in-vehicle devices, in-vehicle components, and the like are often composed of injection-molded synthetic resin molded products.
[0003]
[Problems to be solved by the invention]
By the way, in recent years, weight reduction of vehicles has become an important issue in order to reduce fuel consumption as part of environmental measures, and in order to realize weight reduction for each individual vehicle component constituting the vehicle. Various prototypes and developments such as material changes have been made. Here, in the air conditioner case etc. of the air conditioner unit described above, a so-called “resin molded product with a foamed resin sheet” in which a portion that is not required to have a high strength is replaced with a foamed resin sheet that is lighter than a normal resin can reduce the weight. Proposals have been made to plan. In such a resin molded product with a foamed resin sheet, it is possible to improve heat insulation performance, soundproofing / sound absorption performance, etc. as well as weight reduction due to the characteristics of the foamed resin sheet.
[0004]
However, in the resin molded product with the foamed resin sheet described above, the resin molded part and the foamed part are foamed by sticking or adhering the edge part of the foamed resin sheet to the resin molded part that has been injection molded into a required shape in the subsequent process. The resin sheet was joined. For this reason, in order to manufacture a resin molded product with a foamed resin sheet, a molding process for the resin molded part and a joining process for the foamed resin sheet to the resin molded part are required. There was an inherent problem to be invited. In addition, when the resin molded portion and the foamed resin sheet are joined, the edge portion of the foamed resin sheet and the required position of the resin molded portion may not be reliably adhered or adhered (such as an operator's work mistake). It was impossible to stabilize the bonding strength between the resin molded part and the foamed resin sheet at a high level.
[0005]
OBJECT OF THE INVENTION
The present invention has been proposed in order to suitably solve the above-described problem, and simultaneously reduces the cost by simultaneously performing the molding step of the resin molded portion and the bonding step of the foamed resin sheet to the resin molded portion. An object of the present invention is to provide a method for molding a resin molded product with a foamed resin sheet that can stabilize the bonding strength between the resin molded part and the foamed resin sheet.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems and achieve the intended purpose, the present invention provides :
The molding surface of the first mold constituting the Lee Njekushon mold sets foamed resin sheet molded to the required shape,
By closing the first mold and the second mold that is paired with the first mold, the foamed resin sheet is held at a required position in a cavity defined in both molds,
Injecting the resin in the molten state into the cavity, and bringing the resin into contact with the edge of the foamed resin sheet, the edge is in a molten state,
A method of molding a resin molded product with a foamed resin sheet in which a resin molded part and a foamed resin sheet are joined together by fusing the resin in a molten state and the edge portion in a molten state to each other ,
A space portion that communicates with the cavity and allows inflow of the resin in a molten state at a portion facing the edge of the foamed resin sheet on at least one molding surface of the first mold and the second mold. Provided,
Only the end edge portion is melted by adjusting the pressure by the inflow of the resin into the space portion .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, the method for molding a resin molded product with a foamed resin sheet according to the present invention will be described below with reference to the accompanying drawings, taking a preferred example.
[0008]
FIG. 1 is a schematic perspective view showing an example of a resin molded product with a foamed resin sheet molded by the molding method according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. The entire resin molded product 10 with a foamed resin sheet has a tray shape, and a resin molded portion 12 molded in a tray shape from an olefin-based resin material such as polypropylene, and a substantially entire bottom portion 14 of the resin molded portion 12. And a substantially rectangular foamed resin sheet 16 formed by foaming an olefin-based resin material such as polypropylene. In such a resin molded product 10 with a foamed resin sheet, since the foamed resin sheet 16 is formed in a light weight, it is considerably lighter in weight than a resin molded product having the same shape in which the entire resin molded part is formed by injection molding. It is planned. In addition, due to the characteristics of the foamed resin sheet 16, improvements in heat insulation performance, soundproofing / sound absorption performance, and the like can be expected. However, since the foamed resin sheet 16 has appropriate elasticity and flexibility, the strength and rigidity are somewhat lowered.
[0009]
FIG. 3 is a cross-sectional view schematically showing an example of an injection mold 20 that can mold the resin molded product 10 with a foamed resin sheet shown in FIGS. 1 and 2. The injection mold 20 includes a first mold (core mold) 22 having a convex molding surface 24 and a second mold that forms a concave molding surface 28 and forms a pair with the first mold 22. (Cavity mold) 26, and by closing the molds 22, 26, a cavity 30 for molding the resin molded product 10 with the foamed resin sheet is defined inside (FIG. 4). Here , an example of a vertically opened type in which the first mold 22 and the second mold 26 are opened in the up-down direction is illustrated, but a left-right opened type in which the first mold 22 and the second mold 26 are opened in the left-right direction. It is possible to suitably mold the resin molded product 10 with the foamed resin sheet of the embodiment even with this injection mold.
[0010]
On the molding surface 24 of the first mold 22, a plurality of locking pins 32 for temporarily fixing the sheet 16 are arranged at appropriate positions so that the foamed resin sheet 16 can be set as will be described later. It is installed. On the other hand, on the molding surface 28 of the second mold 26, the foam temporarily fixed to the molding surface 24 of the first mold 22 when the first mold 22 is closed to the second mold 26. A linear projecting piece portion (linear contact portion) 34 is provided so as to linearly crush the inner portion offset inward by a required amount (for example, about 5 mm) along the edge portion 18 of the resin sheet 16. (FIGS. 4 and 5). As shown in an enlarged view in FIG. 5, the cross-sectional shape in the short direction of the linear projecting piece portion 34 is a substantially trapezoidal shape having a narrow strip-like plane at the tip, and enters the foamed resin sheet 16. Thus, the sheet 16 is easily crushed.
[0011]
Next, the foamed resin sheet shown in FIG. 1 is utilized by using the injection mold 20 shown in FIG. 3 comprising the first mold 22 and the second mold 26 of the upper and lower open type configured as described above. A method for molding the resin-molded product with material 10 will be specifically described.
[0012]
(Set of foamed resin sheet material)
First, as shown in FIG. 3, the foamed resin sheet 16 shaped into a required shape and size is mounted on the molding surface 24 of the first mold 22 in the injection mold 20 that has been opened using the locking pins 32. set. The protruding length of the locking pin 32 is preferably set shorter than the thickness B of the foamed resin sheet 16. Further, in the resin molded product 10 with the foamed resin sheet of the embodiment, since the foamed resin sheet 16 is disposed on the flat bottom surface portion 14 in the resin molded portion 12, the preforming of the sheet 16 is not necessary, When the shape is complicated, it is desirable to preform the sheet 16 in a required shape in advance by vacuum forming or the like.
[0013]
(Closing mold)
When the setting of the foamed resin sheet 16 is completed, the first mold 22 is closed to the second mold 26 paired with the first mold 22. As a result, the foamed resin sheet 16 is sandwiched from above and below by the molding surface 24 of the first mold 22 and the molding surface 28 of the second mold 26 as shown in FIG. Is done. The thickness C of the portion where the foamed resin sheet 16 is held in the cavity 30 is set to be slightly smaller than the thickness B of the foamed resin sheet 16, and the sheet 16 is moved in the thickness direction by closing the molds 22 and 26. It is sandwiched while being compressed appropriately.
[0014]
When the first mold 22 and the second mold 26 are closed, as shown in FIGS. 5A and 5B, the first mold 22 and the second mold 26 project from the molding surface 28 of the second mold 26. The linear protruding piece 34 comes into the inner portion along the edge 18 of the foamed resin sheet 16 and when the molds 22 and 26 are completely closed, the inner portion is crushed. To come. The protruding amount of the linear protruding piece 34 is set so as to crush the sheet 16 to such an extent that each internal space of the foamed resin sheet 16 formed by foaming is crushed. It is about 1/3 of the normal thickness B of the sheet 16.
[0015]
(Resin injection)
When the first mold 22 and the second mold 26 are closed, the injection nozzle 38 is positioned at the injection port 36 facing the side surface of the mold 20 as shown in FIG. An amount of molten resin 40 is injected into the cavity 30. Thus, the injected resin 40 is sequentially filled into the cavity 30 and finally comes into contact with the end edge 18 of the foamed resin sheet 16 (FIG. 7A).
[0016]
Here, the end edge portion 18 of the foamed resin sheet 16 is heated to a high temperature, and the resin 40 in a molten state is in direct contact with the edge portion 18 and is instantaneously in a molten state. In addition, since the injection pressure is applied to the resin 40, the entire edge 18 is melted at a stretch, and the molten resin 40 reaches the linear projecting piece 34. However, the resin 40 that has reached the linear projecting piece 34 is dammed in the vicinity of the linear projecting piece 34, and the melting of the foamed resin sheet 16 by the resin 40 remains only at the end edge 18. Only the edge 18 is in a molten state (FIG. 7B).
[0017]
When the injection of the required amount of the resin 40 by the injection nozzle 38 is completed, the resin 40 is held as it is until it is solidified to a predetermined hardness. At this time, since the foamed resin sheet 16 and the resin 40 injected into the cavity 30 are both olefin-based resins, as described above, the molten edge portion 18 and the molten resin 40 are different from each other. They will mix and fuse with each other. Therefore, the resin molding part 12 and the edge part 18 of the foamed resin sheet 16 are solidified while being fused to each other.
[0018]
When the resin 40 and the edge 18 are solidified, the first mold 22 is lifted from the second mold 26 to open the mold 20, and then the molding surface 24 of the first mold 22. The resin molded product 10 with the foamed resin sheet formed from is removed from the mold (FIG. 8). At this time, the foamed resin sheet 16 sandwiched between the molds 22 and 26 and appropriately compressed returns to its original thickness B. Then, after removing the mold, the unnecessary portion 42 is cut to complete the molding of the resin molded product 10 with the foamed resin sheet.
[0019]
Thus, in the molding method of the resin molded product with the foamed resin sheet using the injection mold 20 shown in FIG. 3, the molding process of the resin molded part 12 by injection molding and the foamed resin sheet 16 with respect to the resin molded part 12 are performed. Since a joining process can be performed simultaneously, the significant cost reduction concerning shaping | molding of the resin molded product 10 with a foamed resin sheet can be aimed at. In addition, the edge portion 18 of the foamed resin sheet 16 is fused while being mixed with the resin 40 after the molten resin 40 comes into contact with the molten resin 40 so that the molded resin is molded. It is possible to stabilize the bonding strength between the molded part 12 and the foamed resin sheet 16 at a high level. Therefore, insufficient strength and peeling due to defects associated with the joining of the resin molded portion 12 and the foamed resin sheet 16 are appropriately prevented.
[0020]
FIG. 9 is an explanatory sectional view showing an injection mold 20 according to an embodiment of the present invention . The foamed resin sheet is formed on the molding surface 24 of the first mold 22 based on the injection mold shown in FIG. As shown in FIG. 9 (a), a space portion 44 that communicates with the cavity 30 and allows the inflow of the resin 40 in a molten state is additionally formed at a portion facing the end edge portion 16 of FIG. . In the mold 20 of this embodiment , it is difficult to control the injection pressure of the resin 40 injected into the cavity 30 by the injection nozzle 38, and the progress of the resin 40 cannot be blocked by the linear projecting piece 34. When the foamed resin sheet 16 is melted more than necessary, a part of the resin 40 is caused to flow into the space 44 to adjust the pressure. Thereby, even when the injection pressure of the resin 40 is too high, the melting of the foamed resin sheet 16 by the resin 40 can be melted only at the end edge 18 so that only the end edge 18 can be melted. (FIG. 9B).
[0021]
FIG. 10 is an explanatory cross-sectional view showing another example of the linear contact portion for restricting the progress of the resin 40 injected into the cavity 30. For example, in FIG. 10A, two rows of linear protrusions 34 and 34 that crush the edge 18 of the foamed resin sheet 16 from the lower side are adjacent to and parallel to the molding surface 28 of the second mold 26. Since the crushing region with respect to the end edge portion 18 is enlarged, the progress of the resin 40 can be more reliably stopped. Further, FIG. 10B shows that two rows of linear projecting pieces 34, 34 that crush the lower side of the edge 18 of the foamed resin sheet 16 are appropriately spaced from the molding surface 28 of the second mold 26. In addition to projecting in parallel, one row of linear projecting piece portions 34 that crush the upper side of the end edge portion 18 are projected from the molding surface 24 of the first mold 22, and a total of three linear shapes are provided. Since the crushing region with respect to the end edge 18 is further expanded by the projecting pieces 34, 34, 34, the progress of the resin 40 can be more reliably blocked. Further, in FIG. 10C, a linear protruding piece 34 that pushes up the lower side of the edge 18 of the foamed resin sheet 16 protrudes from the molding surface 28 of the second mold 26 and the linear protruding piece. The linear groove portion 46 that accommodates the edge portion 18 pushed up by the portion 34 is formed in a concave shape on the molding surface 24 of the first mold 22, and is formed by the linear protrusion piece portion 34 and the linear groove portion 46. Since the end edge 18 is crushed while being largely deformed, the progress of the resin 40 can be reliably dammed.
[0022]
In the above embodiment, the case where the linear projection piece 34 is provided on the molding surface 28 of the second mold 26 is illustrated, but the linear projection piece 34 is provided on the molding surface 24 of the first mold 22. You may do it.
[0023]
Further, the resin molded product 10 with the foamed resin sheet that can be molded by the molding method of the resin molded body with the foamed resin sheet of the present embodiment is not limited to the shape illustrated in FIG. Sizes can be molded.
[0024]
【The invention's effect】
As described above, in the method for molding a resin molded body with a foamed resin sheet according to the present invention, the molding step of the resin molded portion and the bonding step of the foamed resin sheet to the resin molded portion can be performed simultaneously. There is a beneficial effect that can greatly reduce the cost of molding a resin molded product with a foamed resin sheet. Moreover, since the edge of the foamed resin sheet is once melted by the resin in the molten state and then melted while being mixed with the resin, the molded resin molded portion and the foamed resin sheet are joined. It is possible to stabilize the strength at a high level. Therefore, there are advantages such as insufficient strength related to the bonding between the resin molded portion and the foamed resin sheet, and prevention of peeling due to defects. In addition, since the pressure of the resin is adjusted in the space that allows the inflow of the resin, it is possible to appropriately melt only the edge of the foamed resin sheet.
Further, at least one of the molding surface of the first mold and the second mold in the mold, linear to crush the inner portion along the edge portion of the foamed resin sheet upon mold closing the molds by the abutment projecting from, Ru can der thereby melting only the edge of the dam by the foam resin sheet material and resin in a molten state in the linear contact portion.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an example of a resin molded product with a foamed resin sheet molded by a molding method according to a preferred embodiment of the present invention.
2 is a cross-sectional view taken along line II-II in FIG.
FIG. 3 is an explanatory cross-sectional view showing a state in which a foamed resin sheet is set on the molding surface of the first mold when the first mold and the second mold constituting the injection mold are opened. .
FIG. 4 is an explanatory cross-sectional view showing a state in which a first mold in which a foamed resin sheet is set and a second mold paired with the first mold are closed.
FIGS. 5A and 5B are cross-sectional views of a main part when the first mold and the second mold are closed, in which FIG. 5A shows a state immediately before the mold closing is completed, and FIG. The state where the linear protruding piece projecting from the molding surface of the second mold upon completion of the closing crushes the inner part along the edge of the foamed resin sheet is shown.
FIG. 6 is an explanatory cross-sectional view showing a state in which resin is injected into a cavity of a mold that is closed.
FIG. 7 (a) is an explanatory cross-sectional view showing a state in which the molten resin melts the edge of the foamed resin sheet when the injection of the resin into the cavity is completed; (b) is the A section enlarged view of (a).
FIG. 8 is an explanatory cross-sectional view showing a state where the first mold is opened from the second mold after the injected resin is solidified, and the molded resin molded product with the foamed resin sheet is removed.
FIG. 9A is a cross-sectional view showing the injection molding die of the embodiment provided with a space for adjusting the pressure in a state where the mold is closed with the foamed resin sheet set, and FIG. It is sectional drawing shown in the state which injected resin to the cavity.
FIG. 10 is an explanatory cross-sectional view showing another example of the linear contact portion, in which (a) shows a configuration in which two rows of linear projecting piece portions project from the molding surface of the second mold. , (B) shows a form in which two linear protrusions project from the molding surface of the second mold and one linear projection protrudes from the molding surface of the first mold. c) shows a form in which a linear groove portion is provided in the molding surface of the first mold when a linear projection piece is provided on the molding surface of the second mold.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Resin molded product with a foamed resin sheet 12 Resin molding part 16 Foamed resin sheet 18 End edge part 20 Injection molding die 22 1st metal mold | die 26 2nd metal mold | die 30 Cavity 34 Linear protrusion part (linear contact part)
40 Resin 44 Space

Claims (2)

The molding surface of the Lee Njekushon mold first mold constituting the (20) (22), sets the foamed resin sheet (16) molded to the required shape,
By closing the first mold (22) and the second mold (26) that is paired with the first mold (22), the foamed resin sheet (16) is defined inside both molds (22, 26). Hold it in the required position in the cavity (30),
The molten resin (40) is injected into the cavity (30), and the resin (40) is brought into contact with the edge (18) of the foamed resin sheet (16) so that the edge (18 ) In a molten state,
Foamed resin in which the resin molded part (12) and the foamed resin sheet (16) are joined by fusing the resin (40) in a molten state and the edge part (18) in a molten state to each other A method of molding a resin molded product (10) with a sheet ,
The cavity (30) communicates with a portion facing the edge (18) of the foamed resin sheet (16) on at least one molding surface of the first mold (22) and the second mold (26). A space (44) that allows the resin (40) in a molten state to flow in,
A foamed resin sheet characterized in that only the end edge (18) is melted by adjusting the pressure by inflow of the resin (40) into the space (44). Molding method for resin-molded products. At least one molding surface of the first mold (22) and second mold (26), said second mold (26) and said first mold (22) and upon closing mold Protruding a linear contact portion (34) that crushes the inner portion along the edge (18) of the foamed resin sheet (16),
The resin (40) said linear contact portion (34) with dam stopped as foam molding method of the resin sheet laminated resin molded article of claim 1 wherein the the in a molten state.

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