JP4204104B2 - Manufacturing method of epidermis - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a resin skin having a protective layer as an innermost layer.
[0002]
[Prior art]
As automotive interior parts such as instrument panels, resin molded products in which the surface of a hard synthetic resin core is covered with a soft synthetic resin skin may be used. In addition, the resin molded product as described above is manufactured by a so-called skin-integrated injection molding method in which a skin is placed in an injection mold, a molten resin is injected onto the inner surface of the skin, and a core is integrally molded with the inner surface of the skin. Often.
[0003]
In the above-mentioned skin integral injection molding method, since the molten resin is injected on the inner surface of the resin skin, the skin is melted and deformed by the heat of the molten resin at the resin inlet, and the effect appears on the surface of the skin. The appearance of the resin molded product may be impaired. In particular, in the case of a resin molded product that requires a soft feeling on the surface, the outer skin may be composed of a plurality of layers and a foam layer formed on the innermost layer (back layer), in which case the foam layer is non-foamed. Since it has the property of being more easily thermally deformed than the above-mentioned one, the problem caused by the molten resin during the skin-integrated injection molding becomes large.
[0004]
In order to eliminate the problems during the skin integral injection molding, it has been proposed that a protective layer made of a hard resin is provided on the entire back surface of the skin as the innermost layer of the skin.
[0005]
However, when a skin having a protective layer as the innermost layer is manufactured by the powder slush molding method, which is often used as a simple molding method for a resin skin, the hard protective layer formed on the entire back surface of the skin interferes. Therefore, it is difficult to remove the mold at the undercut shape, and if the mold is forcibly removed, there is a problem that the surface of the skin is broken and wrinkles or scratches occur.
[0006]
In the powder slush molding method, a thermoplastic resin powder is adhered to and melted on the mold surface by the heat of the mold surface of the mold, and then a resin film is formed. Therefore, when molding a multi-layer skin having the protective layer as the innermost layer, it is difficult for heat from the mold surface to be transferred to the resin portion for the protective layer, and the protective layer cannot be formed due to insufficient heating. There is also a problem that the quality of the protective layer tends to deteriorate. In particular, when powder slush molding is performed on a skin having a foam layer as an intermediate layer, the heat of the mold surface is not easily transmitted to the protective layer resin due to the heat insulating property of the foam layer, and it is more likely to cause poor molding of the skin.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems, and can form a protective layer at a desired position on the back surface of the skin, and can be easily removed from the powder slush mold, and further, the number of defective products can be reduced. Thus, the production efficiency is improved, and in addition, an economical method for producing a resin skin is provided.
[0008]
[Means for Solving the Problems]
That is, according to the first aspect of the present invention, in the production of a resin skin having a protective layer as an innermost layer in a predetermined portion of the skin, a single-layer or multiple-layer resin film is formed on the mold surface of the slush molding die by powder slush molding. Then, the protective layer planned portion on the inner surface of the resin film in the slush mold is surrounded by a masking plate, and a gap is provided between the lower end of the masking plate and the inner surface of the resin film, and the protective layer resin powder is formed in the protective layer planned portion. the deposited in layers by powder coating Rutotomoni, near the periphery of the protective layer portion reserved when powder coating, the protective layer of the resin powder for protective layer rebounded by spraying resin powder for the protective layer on the masking plate The present invention relates to a method for producing an epidermis, wherein the epidermis is demolded after adhering to the vicinity of the periphery of a predetermined portion, heating and melting, and forming a protective layer by cooling.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing a part of a skin manufactured according to an embodiment of the present invention, FIG. 2 is a process view showing a powder slush molding process, FIG. 3 is a cross-sectional view showing a powder coating process, and FIG. FIG. 5 is a cross-sectional view showing a part of the skin manufactured according to another embodiment.
[0010]
FIG. 1 is a sectional view showing a part of an outer skin 10 manufactured according to an embodiment of the present invention. The skin 10 is made of a thermoplastic synthetic resin, and is composed of a surface layer 20 and a protective layer 40 laminated on a required portion of the back surface thereof, and has a surface shape corresponding to the use of the skin 10.
[0011]
The surface layer 20 is formed by powder slush molding as will be described later. The surface layer 20 is made of a soft resin such as a polyolefin-based thermoplastic elastomer resin (TPO) and constitutes the design surface of the skin 10. The protective layer 40 is formed integrally with a required portion on the back surface of the surface layer 20 by powder coating as will be described later. The protective layer 40 is made of an olefin resin or the like and is usually harder than the surface layer 20. Moreover, when it has the site | part 12 which becomes an undercut shape with respect to the demolding direction at the time of skin manufacture like the skin 10 of this example, the undercut shape site | part 12 is located outside the periphery of the said protective layer 40. Thus, the protective layer 40 is not present in the undercut portion 12. As a result, the flexibility of the epidermis is not impaired even in the undercut-shaped portion 12, and demolding is facilitated. In addition, although the skin 10 of this example consists of two layers, the other layer which consists of a foaming layer etc. may be provided between the said surface layer 20 and the protective layer 40, and may be made into three or more layers as a whole.
[0012]
Next, the method for manufacturing the skin according to the present invention will be described taking the case of the skin 10 as an example. The production of the skin consists of a powder slush molding step shown in FIG. 2 and a powder coating step shown in FIGS.
[0013]
In the powder slush molding step, as shown in FIG. 2A, the resin film to be the surface layer 20 is molded using a molding device 30 including a powder slush molding die 31 and a bucket 35. The powder slush mold 31 has a mold surface 33 adapted to the outer surface shape of the skin 10, and the mold surface 33 can be heated to a required temperature by the heating means 38. The heating means 38 in this example is provided by disposing a heat medium supply pipe on the back side of the mold surface 33 and flowing heating oil or the like through the heat medium supply pipe. Further, the bucket 35 is formed with an open accommodating portion 36, and a thermoplastic resin powder 60 such as TPO is accommodated in the accommodating portion 36.
[0014]
The mold surface 33 of the powder slush mold 31 is heated to a predetermined temperature at which the resin powder 60 is melted, and the periphery of the powder slush mold 31 and the bucket 35 are combined with no gap and closed. Then, the molding device 30 is rotated around the rotation shaft 37 by a rotation device (not shown), and the resin powder 60 in the bucket 35 is replaced with the powder slush molding die 31 as shown in FIG. It is dropped and brought into contact with the surface 33. The resin powder 60 in contact with the mold surface 33 is melted by the heat of the mold surface 33 and adheres to the mold surface 33, thereby forming a molten resin film 61 (FIG. 2C). Further, when the powder slush mold 31 is inverted and the bucket 35 returns to its original position, the excess resin powder 60 that has not adhered to the mold surface 33 falls freely and is returned into the bucket 35.
[0015]
By repeating the rotation of the powder slush molding device 30 for a required time or a predetermined number of times, the resin film 61 formed on the mold surface 33 of the powder slush molding die 31 has a predetermined thickness, and then the rotation is stopped. As for the heating, the heat (temperature) of the resin film 61 is set to a heat amount (temperature) at which the resin powder for the protective layer can be melted during the powder coating process to be performed later. The heating is stopped or the heating is continued in consideration of the time until or the type of the protective layer resin powder sprayed in the powder coating process.
[0016]
Next, the powder slush mold 31 and the bucket 35 are separated and a powder coating process is performed to form the protective layer 40. In this powder coating process, first, as shown in FIGS. 3 and 4, the protective layer planned portion 22 on the surface of the resin film 61 in the slush mold 31 is surrounded by a masking plate 54.
[0017]
The masking plate 54 is made of a metal plate or the like. In this example, the masking plate 54 is provided so as to hang from the frame 50 combined with the powder slush mold 31. The lower end 55 of the masking plate 54 is spaced a predetermined distance above the inner surface of the resin film 61 to provide a gap 57. The gap 57 is preferably about 5 to 10 mm. Furthermore, in this example, the positional relationship between the peripheral edge 23 of the protective layer planned portion where the masking plate 54 is arranged and the portion 12 that is an undercut shape with respect to the demolding direction at the time of subsequent demolding is as described above. The undercut-shaped portion 12 is arranged outside the peripheral edge 23 of the protective layer planned portion.
[0018]
After the protective layer planned portion 22 is surrounded by the masking plate 54, the protective layer resin powder 62 is sprayed onto the protective layer planned portion 22 of the resin film by a spray gun 51 connected to a powder coating machine (not shown). Coating is performed, and the protective layer resin powder 62 is adhered to the protective layer planned portion 22 in layers by the heat of the resin film, and melted to form the molten protective resin layer 63. As the protective layer resin powder 62, an appropriate thermoplastic resin powder is used, but in order to improve the compatibility (adhesiveness) with the resin film 61, the same or the same kind of material as the resin film 61 is preferable. In this example, the resin film 61 is made of a polypropylene resin similar to TPO.
[0019]
Since the protective layer planned portion 22 is surrounded by the masking plate 54 during the powder coating, the protective layer resin powder 62 is prevented from adhering to other portions than the protective layer planned portion 22. Further, around the periphery of the protective layer planned portion 22, the protective layer resin powder 62 is sprayed on the masking plate 54 and the bounced resin powder 62 is caused to enter the gap 57 at the lower end 55 of the masking plate. It is performed by adhering to the surface of the resin film 61. In this way, the protective layer resin powder 62 is less likely to leak out of the protective layer planned portion 22 and can be sufficiently adhered to the periphery 23 of the protective layer planned portion 22. Further, since the lower end 55 of the masking plate 54 is not in contact with the resin film 61, the protective layer resin powder 62 continuously adheres from the lower portion of the masking plate 54 to the protective layer planned portion 22 to form a protective layer. The protective layer is not pulled by the lower part of the masking plate at the time of subsequent demolding, and is not torn or irregular, resulting in poor demolding.
[0020]
In addition, it is preferable to use electrostatic powder coating as the powder coating. In electrostatic powder coating, if the resin powder for the protective layer is charged by corona discharge or friction and the protective layer planned part side is grounded, the resin film on the protective layer planned part side has little heat. Even if it exists, resin powder can be made to adhere efficiently. The resin powder attached to the resin film can be heated by heating from above the powder slush mold with a heater or the like.
[0021]
Then, the resin film 61 and the molten resin layer 63 for the protective layer are cured by natural cooling thereafter, blowing cold air, or flowing cold water into the heating medium supply pipe, and the surface layer 20 formed from the resin film 61. 1 is formed by integrating the protective layer 40 formed from the molten resin layer 63 for protective layer, and is removed from the powder slush mold 31. At this time, since the protective layer 40 does not exist in the undercut portion 12, the demolding of the skin 10 is not disturbed.
[0022]
In the case of manufacturing a three-layer structure in which the foam layer 24 is provided between the surface layer 20A and the protective layer 40A, as in the skin 10A shown in FIG. 5, in the powder slush molding step, the resin film on the surface layer After the formation, the bucket may be replaced with a bucket in which the foam layer resin powder is accommodated to continue the powder slush molding, and then the powder coating process may be performed. Further, in the production of a skin composed of four or more layers, a required number of resin films may be laminated in the powder slush molding process in the same manner as described above, and then the powder coating process may be performed.
[0023]
【The invention's effect】
As described above, according to the method for manufacturing the skin of the present invention, since the protective layer is formed by powder coating using a masking plate after powder slush molding, the protective layer is placed at a desired position. It can be provided, and it is not necessary to form a protective layer in unnecessary parts, so material can be saved, and it is difficult to remove due to the presence of the protective layer in the undercut shape part, and creases and scratches caused by the difficulty in removing the mold A skin with a good appearance can be obtained economically. Furthermore, since the protective layer, which is the innermost layer of the epidermis, is formed by powder coating following powder slush molding, the heat retained by the resin film during powder slush molding can be used, providing efficient and economical protection. A layer can be formed. In addition, the skin manufactured in this way is suitable for skin-integrated injection molding.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a part of an epidermis obtained by an embodiment of an epidermis manufacturing method of the present invention.
FIG. 2 is a process diagram of powder slush molding.
FIG. 3 is a cross-sectional view during powder coating.
4 is an enlarged cross-sectional view of a main part of FIG.
FIG. 5 is a cross-sectional view showing a part of the skin manufactured in another example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10,10A Skin 12 Undercut shape part 20 Surface layer 22 Protection layer planned part 23 Protection layer planned part periphery 24 Foam layer 30 Powder slush molding device 31 Powder slush molding die 33 Mold surface 35 Bucket 36 Housing part 37 Rotating shaft 40, 40A Protective layer 51 Spray 54 Masking plate 55 Lower end of masking plate 57 Gap 60 Resin powder for resin film 61 Resin film 62 Resin powder for protective layer 63 Resin powder for molten protective layer

Claims (1)

In the production of a resinous skin having a protective layer as an innermost layer in a predetermined part of the skin, a single-layer or multiple-layer resin film is formed on the mold surface of the slush molding die by powder slush molding, and then the resin in the slush molding die The protective layer planned portion on the inner surface of the film is surrounded by a masking plate, a gap is provided between the lower end of the masking plate and the inner surface of the resin film, and the protective layer resin powder is adhered to the planned protective layer portion by powder coating. In addition, when powder coating is performed around the periphery of the protective layer planned portion, the protective layer resin powder bounced off by spraying the protective layer resin powder onto the masking plate is adhered to the vicinity of the protective layer planned portion. A method for producing an epidermis, wherein the epidermis is demolded after heating and melting and forming a protective layer by cooling.

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