JP4226974B2 - Manufacturing method of two-color molded products - Google Patents

Description

The present invention relates to a two-color molded article prepared how.

  In general, the compact includes a container body having a recess for housing cosmetics and a lid body that covers the container body and has a mirror housing recess on the back surface (see, for example, Patent Document 1). And these compact components, such as a container body and a cover body, are usually molded articles each made of one kind of resin.

  On the other hand, compacts are required not only for functionality but also for beauty of appearance. As one of the methods for expressing the beauty, the outer surface of a container body or lid made of the above-mentioned one kind of resin is used. It is known to coat with a transparent or translucent resin.

As a method for realizing this, there is a two-color molding method. For example, it is a method in which a portion located inside the compact of the container body and the lid body is primarily molded with a colored opaque resin, and a portion located outside thereof is secondarily molded with a transparent or translucent resin.
JP 2003-70531 A

  However, if a two-color molding of a concave peripheral wall with a low height, such as a compact container or lid, warpage occurs in the direction opposite to the concave formation side. The cause of this is not clear, but is considered to be due to low rigidity and thermal residual stress due to the low height of the peripheral wall of the recess. And even if the above warped parts are assembled and made compact, the container body and the lid body cannot be engaged and the lid cannot be formed, or even if the lid is made, there is a gap between the container body and the lid body. I can do it.

The present invention has been made in view of such circumstances, and warpage is unlikely to occur when two-color molding is used to obtain a container having a low peripheral wall height, such as a compact container or lid. providing color article producer how to its purpose.

In order to achieve the above object, a method for producing a two-color molded article of the present invention comprises a two-color molded article that is provided with a flat plate-like portion and a ridge formed around the plate-like portion and is two-color molded in the thickness direction. after a process of manufacturing, to set the height of the upper Kitotsu ridges below 2mm above 8 mm, it was molded primary with a bicycloalkenyl cut softening point 98 ° C. or higher 110 ° C. or less of the MAS resin or a heat ABS resin, on the outside of the plate-shaped portion and the ridges, Ru preparative structure that 2 to primary molding by using a Vicat softening point 82 ° C. or higher 96 ° C. or less of the ABS resin.

The present inventor, when manufacturing a two-color molded product including a flat plate portion and a protruding portion formed around the flat portion, the protruding portion (periphery wall of the recessed portion) like a compact container or lid. In order to make it difficult for warping to occur even when the height of the resin is low, intensive research was conducted on the resin for primary molding .

Results of that study, the use of more than Vicat softening point 98 ° C. as a resin for primary molding, even if primary molding by setting the height of the ridge to below a low value 2mm or 8mm The inventors have found that warpage is less likely to occur and have reached the present invention.

  According to the method for producing a two-color molded product of the present invention, since the resin for primary molding uses a Vicat softening point of 98 ° C. or higher, the height of the protruding portion formed around the flat plate portion is 2 mm. Even if the primary molding is set to a low value of 8 mm or less, warpage is unlikely to occur.

And since the two-color molded product obtained by the manufacturing method of the two-color molded product is molded by the manufacturing method of the two-color molded product, there is almost no warpage.

  Next, the present invention will be described in detail with reference to the drawings.

  1 to 4 show an embodiment of a method for producing a two-color molded product of the present invention. In this method, as shown in FIG. 6, the flat plate-like portions 10a and 20a and the ridges 10b and 20b formed around the plate-like portions 10a and 20a, such as the container body 1 and the lid body 2 which are compact components for housing cosmetics. Two-color molding of a shallow container shape having concave portions 10 and 20 each having a height H (see FIG. 7) of convex portions (peripheral walls of the concave portions 10 and 20) 10b and 20b of 2 mm or more and 8 mm or less. It is a method obtained by. In this method, a resin having a Vicat softening point of 98 ° C. or higher is used as the primary molding resin.

  That is, in this embodiment, the container body 1 will be described as an example. First, as shown in FIG. 1, the first cavity mold 31 and the core mold 40 are clamped, and the primary space is formed in the formed molding space. Inject molding resin. Thereby, the primary molded object 11 in which the said recessed part 10 was formed is formed. At this time, the height H of the convex portion 40a corresponding to the concave portion 10 in the core mold 40 is set to the same value as the height H (see FIG. 7) of the convex portion (the peripheral wall of the concave portion 10) 10b. .

  Next, as shown in FIG. 2, the first cavity mold 31 and the core mold 40 are separated. Then, with the primary molded body 11 remaining in the core mold 40, as shown in FIG. 3, it is moved to a position where the second cavity mold 32 acts, and the second cavity mold 32 and the core mold 40 with the primary molded body 11 remaining therein are clamped, and a secondary molding is formed in a molding space formed between the second cavity mold 32 and the primary molded body 11. Inject resin. Thereby, the secondary molded object 12 is formed in the outer side (opposite side to the recessed part 10 formation side) of the primary molded object 11. FIG. By this formation, the secondary molded body 12 is bonded to the primary molded body 11.

  Then, as shown in FIG. 4, the second cavity mold 32 and the core mold 40 are separated from each other, and a two-color molded product (the container body 1 shown in FIG. 6) composed of the primary molded body 11 and the secondary molded body 12 described above. ) Is obtained.

The lid 2 shown in FIG. 6 is also obtained in the same manner as the method shown in FIGS. That is, as shown in FIG. 5, after forming a primary molded body 21 a recess 20 is formed, by forming a secondary molded body 22 on the outside of the primary molded body 21, these primary molded body A two-color molded product (the lid body 2 shown in FIG. 6) composed of 21 and the secondary molded body 22 is obtained.

  The molding material used for the container 1 and the lid 2 will be described. Examples of the resin having a Vicat softening point of 98 ° C. or higher used for primary molding include MAS resin and heat-resistant ABS resin.

  Moreover, it does not specifically limit as resin used for secondary shaping | molding, ABS resin, PC resin, etc. which are normally used for shaping | molding are mention | raise | lifted. The same resin as the primary molding resin may be used, but it is preferable to use a resin having a lower Vicat softening point than that of the primary molding resin. This is because the warpage can be further reduced.

  In particular, when the two-color molded product of the above example is the container body 1 or the lid body 2 constituting the compact shown in FIG. 6, the inner parts of the compact (primary molded bodies 11, 21) are colored and opaque resin. When the outer portions (secondary molded bodies 12, 22) are molded with a transparent resin, the primary is transmitted through the transparent secondary molded bodies 12, 22 in either a closed state or an open state. Since the molded bodies 11 and 21 can be seen, the appearance can be expressed beautifully. On the other hand, when the inner part of the compact is molded with a transparent resin and the outer part is molded with a colored opaque resin, the inner appearance can be expressed beautifully when the compact is opened.

  The colored opaque resin is colored by adding a pigment or the like to a colorless and transparent resin. In addition, the transparent resin may be translucent, and in that case, it is made translucent by adding a pearl pigment to the colorless and transparent resin. The transparent resin may be colored and transparent. Furthermore, in addition to the pigment, ultraviolet absorbing particles or the like may be added to the resin as appropriate. The above-mentioned “transparent” and “semi-transparent” are transparent so that the color of the colored body can be visually confirmed when the colored body is seen through the molded body made of the transparent or translucent resin. Means sex.

  Next, examples will be described together with comparative examples.

[Example 1]
The compact lid 2 was molded in two colors in the same manner as in the above embodiment. The obtained lid body 2 has a recess 20 in a portion located inside the compact, and the height H of the peripheral wall (projection strip 20b) of the recess 20 is 8 mm. Further, the side where the concave portion 20 was formed was the primary molded body 21, and MAS resin (U-400, manufactured by Mitsubishi Rayon Co., Ltd.) having a Vicat softening point of 98 ° C. was used as the primary molding resin. The outside was used as the secondary molded body 22 and a transparent ABS resin (Denka Co., Ltd., CL-301, Vicat softening point: 82 ° C.) was used as the secondary molding resin. In addition, the said cover body 2 was made into the substantially rectangular shape, and the magnitude | size was 100 mm x 65 mm. Moreover, the said surrounding wall was formed in the periphery of the substantially rectangular flat plate-shaped part 20a, and the thickness of the surrounding wall of the primary molded object was 2 mm, and the thickness of the surrounding wall of the secondary molded object was 1 mm.

[Example 2]
In the said Example 1, transparent ABS resin (The Denka company make, CL-20, Vicat softening point: 96 degreeC) from which Vicat softening point differs was used as resin for secondary shaping | molding. Other than that, it was the same as in Example 1 above.

Example 3
In the said Example 2, the heat resistant ABS resin (The Denka company make, K-095) which is Vicat softening point 110 degreeC was used as resin for primary shaping | molding. Other than that was carried out similarly to the said Example 2.

Example 4
In the said Example 1, the height H of the surrounding wall (projection strip 20b) of the recessed part 20 was 2 mm. Other than that, it was the same as in Example 1 above.

[Comparative Example 1]
In Example 1 described above, a transparent ABS resin (CL-301 manufactured by Denka Co., Ltd.) having a Vicat softening point of 82 ° C. was used for both the primary molding resin and the secondary molding resin. Other than that, it was the same as in Example 1 above.

[Comparative Example 2]
In Comparative Example 1, a transparent ABS resin (Denka Corporation, CL-20) having a Vicat softening point of 96 ° C. was used as the primary molding resin. Other than that, it was the same as in Example 1 above.

  The lids 2 of Examples 1 to 4 and Comparative Examples 1 and 2 obtained in this manner were visually checked for warpage. The results are shown in Table 1 below. In Table 1, the case where there was no warp or even if there was a slight warp was evaluated as ○, and the case where there was a warp was evaluated as x.

  From the results of Table 1, in Examples 1 to 4 using a Vicat softening point of 98 ° C. or higher as the primary molding resin, there was no warpage or very little, and Vicat softening was used as the primary molding resin. It can be seen that warpage occurred in Comparative Examples 1 and 2 using a point of less than 98 ° C.

  In Example 1, even when the height H of the peripheral wall (projection strip 20b) of the recess 20 was set to 7 mm, 6 mm, 5 mm, 4 mm, and 3 mm, there was almost no warpage as in the above examples.

It is explanatory drawing which shows typically embodiment of the manufacturing method of the two-color molded product of this invention. It is explanatory drawing which shows typically the manufacturing method of the said 2 color molded product. It is explanatory drawing which shows typically the manufacturing method of the said 2 color molded product. It is explanatory drawing which shows typically the manufacturing method of the said 2 color molded product. It is explanatory drawing which shows other two-color molded products typically. It is a perspective view which shows embodiment of the two-color molded product obtained by the manufacturing method of the said two-color molded product. It is explanatory drawing which shows the height of the protruding item | line part of the said 2 color molded product.

Explanation of symbols

10a, 20a Flat portion 10b, 20b Projection

Claims (1)

And a flat plate-like portion and its surroundings formed ridges, a method for producing a two-color molded article molded two-color in the thickness direction, or 2mm height of the upper Kitotsu ridges 8mm or less set, after forming the primary using a bi-cut softening point 98 ° C. or higher 110 ° C. or less of the MAS resin or a heat ABS resin, on the outside of the plate-shaped portion and the ridges, Vicat softening point 82 ° C. or higher 96 ° C. A method for producing a two-color molded product, wherein the secondary molding is performed using the following ABS resin .