JPH07137089A - Injection molding of different material quality resin molded product - Google Patents

Abstract

PURPOSE:To prevent the separation of primary and secondary molded parts by selecting specific resins not fused or hard to fuse at the mutual contact surface of resins as resins used in two-color injection molding and injecting a secondary resin into a primary resin to deform the same to leave a projection in the secondary molded part. CONSTITUTION:In the primary resin of a first shot in a two-color molding method, either a specific resin A (polyacetal resin, polyamide resin or polypropylene resin) a specific resin B (styrenic resin such as an ABS resin or polycarbonate resin) is used and, as the secondary resin of a second shot, the other one of the specific resins is used. A projection 6a such as a rib 6 left in a secondary molded part 9 deformed at the time of the injection molding of the secondary resin is formed at the proper place of a primary molded part 6. In the case of insert molding or outsert molding, the projection may be provided at the proper place of the resin molded product inserted in a mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combination of resin moldings such as keypads for various inputs such as touch-tone telephones and computers, housings of electronic devices, housings for waterproofing and dustproofing, and resins of different materials. The present invention relates to an injection molding method for molding by.

[0002]

2. Description of the Related Art A two-color molding method in which a molding part on a primary side and a molding part on a secondary side are alternately injection-molded with two kinds of resins, and the resin molding around a resin-molded part inserted in a mold. The injection molding method of injecting a resin of a different type from the part to integrate it with the resin molded part, or the resin molded part inserted in the mold partly or partly different from the resin molded part By using the outsert molding method, etc., in which the resin of
Various resin molded products (parts and final products) are molded by combining different resins.

In such injection molding of resins having different materials such as color and physical properties, in the case of the two-color molding method, the contact portion between the molding portion on the primary side and the molding portion on the secondary side, or the insert molding method. In the case of the outsert molding method or the outsert molding method, at the contact part between the resin molded part inserted in the mold and the injection molded resin, the resin is fused and integrated, and the combination of resins is selected as if it were one molded product. Has been done. As a typical combination of resins fused on the contact surface, a combination of ABS resins and a combination of ABS resin and polycarbonate resin are known.

However, in recent years, in order to enhance the function of the resin molded product, there is an increasing number of cases where molding is performed by a combination of resins in which fusion does not occur at the contact surfaces of the resins or in which fusion does not easily occur. As a typical combination of resins that do not or do not easily fuse on the contact surface, polyacetal resin, polyamide resin or polypropylene resin is used for one of the two types, and ABS resin or polycarbonate resin is used for the other one. There are combinations that use.

In the case of molding with such a combination of resins, there is no fusion or insufficient fusion at the contact surfaces of the resins, so it is used during molding or as a product. In the middle of the process, the two types of resin were separated at the contact surface, and one side might drop off.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a primary side and a secondary side in the case of a two-color molding method even if injection molding is performed by using a combination of resins which are not fused on the contact surface or are difficult to fuse. To provide an injection molding method for a resin molded product of a different material, which does not separate or drop the molded portion of the resin on the next side or separate or drop the resin molded part and the injection molded resin in the case of the insert molding method or the outsert molding method. Is.

[0007]

In the injection molding method for a resin molded product of a different material according to the present invention, the primary side resin is injection-molded by the first shot and the secondary side resin is injection-molded by the second shot. In the two-color molding method, one of the specific resin A (polyacetal resin, polyamide resin or polypropylene resin) and the specific resin B (styrene resin such as ABS resin or polycarbonate resin) is used as the resin on the primary side of the first shot. Then
The other of the specific resins A and B is used as the resin on the secondary side of the second shot. The projections such as ribs that are deformed and remain inside the molded portion of the resin on the secondary side are
It is made of resin on the next side and placed.

According to another aspect of the injection molding method of the present invention, the resin molding part is inserted into a mold, and the resin is injection-molded around the resin molding part to integrate the resin molding part with the insert molding. In a method or an outsert molding method in which a resin molded part is inserted into a mold, and a resin is injection-molded on a part or a plurality of parts of the resin molded part to integrate the resin molded part into the mold. Specific resin A (polyacetal resin, polyamide resin or polypropylene resin) and specific resin B are used as molding materials for the resin molded parts
(Styrene-based resin such as ABS resin or polycarbonate resin) is used, and the other of the above-mentioned specific resins A and B is used as the resin to be injection-molded during insert molding or outsert molding. Protrusions such as ribs, which are deformed by the resin injected during insert molding or outsert molding and remain inside the injection molded resin, are formed at appropriate places of the resin molded component to be inserted.

In the injection molding method of the present invention using a resin molded product as a key top, the primary resin molded portion 6 representing the letters, numbers, or figures is injection-molded by the resin on the primary side of the first shot, and the second shot. In the two-color molding method in which the secondary resin molding part 9 surrounding the secondary resin is injection-molded, the specific resin A (polyacetal resin, polyamide resin or polypropylene resin) is used as the primary side resin of the first shot. And specific resin B (styrene resin such as ABS resin or polycarbonate resin) are used, and the other of the specific resins A and B is used as the secondary side secondary resin, and the first shot primary resin is used. The side resin molding portion 6 is deformed at the time of the second shot injection molding, and is deformed in the secondary resin molding portion 9 at a proper position. A projection such as a rib remaining in parts, placed to form a resin of the primary side of the first shot.

In the injection molding method according to another aspect of the present invention in which a resin molded product is used as a key top, a part of characters, numbers or figures is surrounded by a primary side resin molded portion 11 representing the characters, numbers or figures. Separated part 12 of secondary resin
a is present, injection molding is performed on the primary resin molding portion 11 that represents letters, numbers, or figures by the resin on the primary side of the first shot, and around the primary resin molding portion 11 by the resin on the secondary side of the second shot. A method for injection molding of a key top for injection-molding an outer resin molding portion 12 of a secondary resin and an isolation portion 12a of the secondary resin surrounding the first resin, wherein a specific resin A (polyacetal resin) is used as a resin on the primary side of the first shot. , Polyamide resin or polypropylene resin) and specific resin B (styrene resin such as ABS resin or polycarbonate resin),
When the other of the specific resins A and B is used as the resin on the secondary side of the second shot, the resin on the secondary side of the second shot is injection-molded at a position protruding into the space 22d for forming the isolated portion of the secondary resin. A protrusion such as a rib that deforms into a mold is formed by molding the resin on the primary side of the first shot.

[0011]

In the case of the two-color molding method, the key top is formed by molding the portion representing the letters, numbers or figures with the resin on the primary side of the first shot, and surrounding it with the resin on the secondary side of the second shot. As an example, as shown in FIG. 1, the first shot upper mold 2 includes a primary resin molding space 4 filled with the primary resin in the first shot and a primary resin molding space 4 A wedge rib forming space 4a extending from the above is formed.

In the first shot, the resin on the primary side is filled by the injection molding machine from the resin injection port 5 of the first shot into the primary resin molding space 4 and the wedge rib molding space 4a in the mold. As shown, the primary resin molded portion 6 including the wedge rib 6a is molded.

As shown in FIGS. 2 and 3, the first shot upper mold 2 is replaced with the second shot upper mold 3, and the second shot secondary side resin is injected with the injection molding machine. The secondary resin molding space 7 is filled from the inlet 8.

At this time, the heat and pressure of the secondary resin filled in the secondary resin molding space 7 deforms the wedge rib 6a that has been molded in advance, and as shown in FIGS. The deformed shape is left as the deformed wedge rib 6b inside the resin on the secondary side with the shape deformed due to the cooling and solidification of the resin on the secondary side.

As described above, the protrusions such as ribs are provided at appropriate places on the resin molding portion on the primary side of the first shot, and the protrusions such as ribs are deformed by the injection of the molding resin on the secondary side at the time of the second shot to change the primary shape. The method of the present invention for preventing the separation and dropping of the resin on the secondary side and the secondary side can, of course, be applied to the case of molding a resin molded product other than the key top by the two-color molding method.

Next, the case of the insert molding method will be described. As shown in FIG. 12, the insert molding part 23 is preliminarily formed with insert molding part wedge ribs 23a.

As shown in FIG. 13, the insert-molded part 23 is inserted into a predetermined position of the insert-side die 24 of the insert, and the injection-side die 25 of the insert is closed. Resin is filled from the inlet 27 into the molding space 26 of the insert.

At this time, the heat and pressure of the resin filled in the molding space 26 of the insert deforms the wedge ribs 23a of the insert-molded component, and the resin remains in the deformed shape as the filled resin is cooled and solidified. Left inside.

Next, the case of the outsert molding method will be described. As shown in FIG. 14, the resin case 29, which is a resin molded part at the time of outsert, has a wedge rib 29a of the resin case formed in advance. There is.

As shown in FIG. 15, a resin molded part is inserted into the outsert insertion side mold 30 at a predetermined position, and the outsert injection mold 31 is closed. Resin is filled into the molding space 32 of the outsert from the resin injection port 33.

At this time, the space 32 for molding the outsert
The wedge ribs 29a of the resin case are deformed by the heat and pressure of the resin filled in the resin, and as shown in FIG. 16, after being molded into the resin with the deformed shape as the resin filled and cooled and solidified. It is left as a wedge rib 29b.

[0022]

As described above, according to the injection molding method of the different material resin molded product of the present invention using the specific resins A and B, in the two-color molding method, the rib provided on the primary resin molded portion of the first shot is used. Since the projections such as are deformed by the injection molding of the resin on the secondary side of the second shot and remain inside the resin on the secondary side, resin molding parts to be inserted into the mold by the insert molding method or the outsert molding method. Since ribs and other protrusions that have been formed in advance are deformed by injection molding and remain inside the injection-molded resin, even if the resins that do not fuse to each other peel off at the contact surface, the deformed ribs and other protrusions As described above, the molded portions of the resin are connected to each other, and the molded portion of the resin on one side does not fall off.

[0023]

[First Embodiment] First shot including number part 1
This is a two-color molding of a key top in which the next resin molding portion 6 is injection-molded and the second resin molding portion 9 which covers the outside while leaving a numeral portion on the second shot is injection-molded. As shown in FIG. In the upper mold 2 of the shot, the primary resin molding space 4 filled with the resin on the primary side in the first shot, the wedge rib molding space 4a extending from the side surface of the primary resin molding space 4 and the first shot. Resin injection port 5
Are formed.

In the lower mold 1 which is commonly used for both the first shot molding and the second shot molding, the ejecting pin 10 is inserted at a position where it hits both the primary resin molding portion 6 and the secondary resin molding portion 9. Has been.

In the first shot, as shown in FIG. 1, the lower die 1 and the first shot upper die 2 are used.
After closing, the polyacetal resin was used as the resin on the primary side, and the resin injection port 5 of the first shot was used to fill the space 4 for forming the primary resin and the space 4a for forming the wedge rib in the mold by the injection molding machine. As shown in FIG. 5, the primary resin molding portion including the wedge rib 6a is molded.

In the second shot, as shown in FIG. 2, after replacing the first shot upper mold 2 with the second shot upper mold 3 in which the secondary resin molding space 7 is formed, an injection molding machine is used. The secondary resin is filled with ABS resin from the second shot resin injection port 8 provided in the second shot upper mold 3 into the secondary resin molding space 7.

At this time, the heat and pressure of the secondary side resin filled in the secondary resin molding space 7 deforms the wedge rib 6a which was previously molded in the first shot, and as shown in FIG. The deformed wedge rib 6b remains inside the resin on the secondary side with the shape deformed due to the cooling and solidification of the resin on the secondary side.

The key top after the second shot is opened after the upper die 3 of the second shot is opened.
The protrusion pin 10 protrudes from the lower mold 1 and separates it.

As shown in FIG. 6, since the wedge rib 6a extending from the primary resin molding portion 6 remains as a deformed wedge rib 6b having a complicatedly deformed shape inside the resin on the secondary side, Even if the contact portion between the resin molded portion 6 and the secondary resin molded portion 9 separates, the primary resin molded portion 6 and the secondary resin molded portion 9 do not separate and fall off.

[0030]

[Embodiment 2] There is an "O" figure in the resin molding portion on the primary side of the first shot, and the resin on the secondary side of the second shot covers the surroundings by leaving the "O" figure and "O".
When the key top that fills the inside of the key top is molded by the two-color molding method, as shown in FIG.
, There is a secondary resin isolation portion 12a surrounded by the graphic portion of the primary resin molding portion 11 representing "O".

Further, on the back side of the "O" figure portion of the primary resin molding portion 11, the resin on the secondary side from the outer portion 12 of the secondary resin to the secondary resin separating portion 12a at the time of the second shot. Outer resin passage 1 that is a resin flow path that guides
2b and the secondary resin connecting passage 12c and the secondary resin inner passage 12d remain, and the outer portion 12 of the secondary resin and the separating portion 12a of the secondary resin are connected to each other on the back side of the key top.

A primary resin molding portion 11 and a secondary resin molding portion, which are the resin molding portion on the primary side, which is a resin molding portion which is not fused by the two-color molding method or which is unlikely to cause fusion bonding. Outer part 12 of secondary resin, and 2
When the key top of the isolated portion 12a of the secondary resin is molded, the isolated portion 12a of the secondary resin is 1 times larger than the outer portion 12 of the secondary resin which covers the periphery of the primary resin molded portion 11.
It is easier to fall off from the next resin molded portion 11.

Particularly, when another resin molded product is welded to the back side of the key top by ultrasonic welding, the outer passage 12b of the secondary resin or the inner passage of the secondary resin is vibrated by vibration during ultrasonic welding. The resin on the secondary side is divided at or near the portion 12d, and the isolated portion 12a of the secondary resin easily falls off from the primary resin molded portion 11.

When the key top having the secondary resin isolation portion 12a is formed by the two-color molding method, as shown in FIG.
As shown in FIG. 1, the first shot upper mold 13 has a primary resin molding space 15 and an upper surface 15b of the primary resin molding space 15b which extends from the primary resin molding space 15 and corresponds to the graphic display portion of the key top. A wall-shaped wedge rib molding space 15a which is low in height and does not come into contact with the primary resin molding space inner wall 15c surrounding the periphery thereof, and a first shot resin injection port 19 are formed.

Also, the first shot upper mold 13
In the second shot, from the space 22 for forming the outer side of the secondary resin to the space 22d for forming the isolated part of the secondary resin,
In order to form an outer passage forming space 22a of the secondary resin and an inner passage forming space 22c of the secondary resin, which serve as passages for filling the resin on the next side, the outer closing pin 16 and the inner closing pin 17 are It is inserted at a position where the outer portion 12 of the secondary resin and the isolation portion 12a of the secondary resin are formed, and at a position where it contacts the slide pin 18 inserted into the lower mold 14.

The lower mold 14 which is commonly used for the first shot and the second shot has a secondary mold for filling the isolated partial molding space 22d of the secondary resin with the secondary resin during the second shot. The slide pin 18 for forming the secondary resin connecting passage forming space 22b, which is a space connecting the resin outer passage forming space 22a and the secondary resin inner passage forming space 22c, is used for forming the primary resin. Space 1
It is inserted to the position where it touches 5.

Polyacetal resin (Yupital F40-20, manufactured by Mitsubishi Gas Chemical Co., Inc.) is used as the resin on the primary side of the first shot, and the wedge rib molding space 15 is fed from the resin injection port 19 of the first shot from the injection molding machine.
The primary resin molding space 15 including a is filled with the resin on the primary side, and the molding portion 11 of the primary resin including the wedge rib 11a is molded as shown in FIG.

After the first shot is completed, the outer closing pin 16 and the inner closing pin 17 are moved in the upper direction of FIG. 8 to separate the secondary resin from the secondary resin separating portion molding space 22d during the second shot. A space 22a for forming an outer passage of the secondary resin and a space 22c for forming an inner passage of the secondary resin, which serve as passages for filling the inner space, are formed. Then, the first shot upper mold 13 including the outer closing pin 16 and the inner closing pin 17 is separated from the lower mold 14,
As shown in FIG. 5, the second molding upper mold 20 is replaced with the outer molding space 22 for the secondary resin and the space 22d for forming the isolated portion of the secondary resin.

Further, the slide pin 18 inserted into the lower mold 14 is slid in the downward direction of FIG. 9 to form a space 22b for molding the secondary resin connecting passage.

A as the resin on the secondary side of the second shot
BS resin (made by Japan Synthetic Rubber Co., Ltd., JSR ABS3
8B) is used to fill the space 22 for molding the outside of the secondary resin from the resin injection port 21 of the second shot from the injection molding machine, and the space 2 for molding the outside passage of the secondary resin.
The space 22b for connecting and molding 2a and the secondary resin and the space 22c for molding the inner passage of the secondary resin are filled in the space 22d for the isolated partial molding of the secondary resin.

At that time, the wedge rib 11a is deformed by the heat and pressure of the resin on the secondary side filled in the space 22d for forming the isolated part of the secondary resin, and as shown in FIG. The wedge rib 11b after the deformation remains in the deformed shape due to the cooling and solidification, and remains inside the isolated portion 12a of the secondary resin.

The key top after the second shot is released from the lower die 14 by the ejection pin 10 after the upper die 20 of the second shot is opened.

On the back side of the key top having the deformed wedge ribs 11b formed by the two-color forming method of the present invention and on the back side of the key top formed by the conventional two-color forming method having no deformed wedge ribs 11b, Another resin molded part was welded by ultrasonic welding, and a test was conducted to cause the isolated portion 12a of the secondary resin to fall off due to the vibration generated at the time of ultrasonic welding. The dropout rate of the part is 2%, and the dropout rate of the isolated part is 10% in the key top formed by the conventional method.
According to the method of the present invention, the result that the occurrence of dropout can be improved was obtained.

In this embodiment, the wedge rib 11a is 1
A wall-shaped rib that is lower in height than the resin molding space upper surface 15b and does not contact the primary resin molding space inner wall 15c is provided, but it does not fall off from practical use, and the secondary resin isolation portion molding space 22d is formed. If the filling of the secondary side resin into the resin is not hindered, the end of the wall-shaped rib is extended to
5c may be integrated, or the rib may have a cylindrical shape, a conical shape, or other shape protrusions at one or more locations.

[0045]

Example 3 In the insert molding method according to this example,
Preliminarily insert molded part wedge rib 2 as shown in FIG.
The insert-molded part 23 containing 3a is molded by a usual injection molding method using a polyacetal resin.

In the insert-side die 24 of the insert, a part of the insert molding space 26 and the insert molding component 2 are inserted.
A space into which the insert pin 3 is inserted is formed, and the ejecting pin 10 is inserted into an appropriate position corresponding to the insert forming space 26.

After inserting the insert-molded part 23 into a predetermined position of the insert-insertion mold 24, the insert-side mold having the remaining portion of the insert-molding space 26 and the insert resin injection port 27 is formed. 25 and the insert side mold 24 of the insert are closed.

ABS resin is used as the injection molding resin,
The molding space 26 of the insert is filled from the resin injection port 27 of the insert by an injection molding machine.

At this time, the wedge resin 23b for insert molding is deformed by the heat and pressure of the ABS resin filled in the molding space 26 of the insert, and the shape of the wedge rib 23a is deformed as the filled resin is cooled and solidified. It remains inside the ABS resin.

After the injection molding is completed, the insert injection-side mold 25 is separated, and the insert-molded part 23 and the ABS resin as the injection-molding resin are integrated. It is ejected from 24 and separated.

The dissimilar material resin molded product of the present invention molded by using the insert molded part 23 made of polyacetal resin and the injection molded resin made of ABS resin is not affected by vibration and shock due to the effect of the complicatedly deformed insert molded part wedge rib 23a. It will be a solid one that will not fall out even if it is received.

[0052]

[Embodiment 4] In the outsert molding method according to this embodiment, as shown in FIG. 14, the parts for outsert molding have an outsert molding wedge rib 29a molded by ordinary injection molding using a polyacetal resin. The inner case 28 is fitted in the resin case 29 including the inner case 28 with such strength that the inner case 28 does not fall off.

The insert side mold 30 of the outsert has a space for inserting the parts for the outsert molding and a part of the molding space 32 for the outsert, and is projected to an appropriate position corresponding to the parts for the outsert molding. The pin 10 is inserted.

The outsert molding part was inserted into a predetermined position of the outsert insertion side mold 30, and the resin injection port 33 of the outsert and the remaining part of the molding space 32 of the outsert were formed. The injection side mold 31 of the outsert is closed.

ABS resin is used as the injection molding resin,
The injection molding machine fills the outsert molding space 32 from the outsert resin injection port 33.

At this time, the space 32 for molding the outsert
The wedge rib 29a of the resin case is deformed by the heat and pressure of the ABS resin filled in the resin, and remains as the deformed wedge rib 29b inside the resin in the deformed shape as the filled resin is cooled and solidified. .

After the injection molding is completed, the injection-side die 31 of the outsert is separated, and the outsert molding part and the ABS resin which is the injection molding resin are integrated into a molded product.
Insert side die 3 of outsert by the protruding pin 10
It is ejected from 0 and separated.

The foreign material resin molded product of the present invention molded by using the polyacetal resin as the outsert molding component 29 and the ABS resin as the injection molding resin has the effect of vibrations and vibrations due to the effect of the vertically deformed vertical ribs 29b. It is a strong unit that does not fall off even if it receives a shock.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a mold before starting a first shot when a key top is molded by a two-color molding method according to an embodiment of the method of the present invention.

FIG. 2 is a vertical sectional view of a mold before the second shot is started in the two-color molding method.

FIG. 3 is a lateral cross-sectional view of a mold before the second shot is started in the two-color molding method.

FIG. 4 is a cross-sectional view of a mold at the end of the second shot of the two-color molding method.

FIG. 5 is a perspective view of a primary resin molded portion molded by the first shot.

FIG. 6 is a perspective view of a key top completed by the second shot, showing a part of a secondary resin molding portion cut away.

FIG. 7 is a perspective view of a key top manufactured by a two-color molding method according to another embodiment of the method of the present invention.

8 is a vertical cross-sectional view of a mold before starting a first shot of a two-color molding method used for molding the key top of FIG. 7. FIG.

FIG. 9 is a perspective view of a primary resin molded portion molded by the first shot.

10 is a vertical cross-sectional view of a mold before the start of the second shot of the two-color molding method used for molding the key top of FIG. 7.

FIG. 11 is a vertical cross-sectional view of the key top completed by the second shot.

FIG. 12 is a perspective view of a molded part for insert used in an insert molding method according to still another embodiment of the method of the present invention.

13 is a vertical cross-sectional view of an insert molding die in which the insert molded component of FIG. 12 is inserted into a predetermined position.

FIG. 14 is a perspective view of an outsert molding component used in an outsert molding method according to still another embodiment of the method of the present invention.

15 is a vertical cross-sectional view of an outsert molding die in which the outsert molding component of FIG. 14 is inserted at a predetermined position.

FIG. 16 is a perspective view of a molded product completed by the outsert molding method, in which a part of a secondary resin molded portion is cut away.

[Explanation of symbols]

 1 Lower mold of two-color molding method 2 Upper shot of first shot of two-color molding method Upper mold of second shot of two-color molding method 4 Space for primary resin molding 4a Space for wedge rib molding 5 First shot Resin injection port 6 Primary resin molding part 6a Wedge rib 6b Wedge rib after deformation 7 Secondary resin molding space 8 Second shot resin injection port 9 Secondary resin molding part 10 Ejection pin 11 Primary resin molding part 12 2 Outer portion of secondary resin 12a Secondary resin isolation portion 12b Secondary resin outer passage 12c Secondary resin connecting passage 12d Secondary resin inner passage 13 First shot upper mold of two-color molding method 14 Two-color molding method Lower mold 15 Primary resin molding space 15a Wedge rib molding space 15b Primary resin molding space Upper surface 15c Primary resin molding space Inner wall 16 Outside closed Pin 17 Inner closing pin 18 Slide pin 19 First shot resin injection port 20 Second shot upper mold of two-color molding method 21 Second shot resin injection port 22 Secondary resin outer formation space 22a Secondary resin outer passage Molding space 22b Secondary resin connection passage molding space 22c Secondary resin inner passage molding space 22d Secondary resin isolated part molding space 23 Insert molding part 23a of insert molding method Insert molding part wedge rib 24 Insert Insert side mold 25 Insert injection side mold 26 Insert molding space 27 Insert resin injection port 28 Outsert molding part interior part 29 Outsert molding part 29a Outsert molding part wedge rib 29b Wedge after deformation Rib 30 Outsert insertion side mold 31 Out Tosert injection side mold 32 Outsert molding space 33 Outsert resin injection port

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area B29K 55:02 59:00 69:00 77:00 B29L 31:34

Claims (4)

[Claims] 1. A two-color molding method in which a resin on the primary side is injection-molded by a first shot and a resin on the secondary side is injection-molded by a second shot, wherein a specific resin is used as the resin on the primary side of the first shot. Either A (polyacetal resin, polyamide resin or polypropylene resin) or specific resin B (styrene resin such as ABS resin or polycarbonate resin) is used, and the specific resins A and B are used as the secondary side secondary resin. The other one is used, and it is deformed during the injection molding of the resin on the secondary side of the second shot and remains inside the molded portion of the resin on the secondary side at a proper position in the molded portion of the resin on the primary side of the first shot. An injection molding method for a resin molded product of different material, characterized in that protrusions such as ribs are formed of a resin on the primary side of the first shot. 2. An insert molding method in which a resin molded part is inserted into a mold and a resin is injection-molded around the resin molded part to be integrated with the resin molded part, or a resin molded part is inserted into the mold. Then, in the outsert molding method in which a resin is injection-molded on a part or a plurality of parts of the resin-molded part to be integrated with the resin-molded part, the specific resin A is used as a molding material for the resin-molded part to be inserted into the mold. Either one of (polyacetal resin, polyamide resin or polypropylene resin) and specific resin B (styrene resin such as ABS resin or polycarbonate resin) is used, and is specified as a resin to be injection-molded during insert molding or outsert molding. The other resin, A or B, was used and injected into the appropriate position of the resin molded part to be inserted into the mold during insert molding or outsert molding. An injection molding method for a resin molded product of a different material, characterized in that projections such as ribs which are deformed by the resin and remain inside the injection molded resin are formed. 3. A resin molded product is used as a key top, and a primary resin molded portion 6 representing letters, numbers, or figures is injection-molded by the resin on the primary side of the first shot, and the resin on the secondary side of the second shot is injected. In the two-color molding method in which the secondary resin molding portion 9 surrounding the periphery of the first shot is injection-molded, the specific resin A (polyacetal resin, polyamide resin or polypropylene resin) and the specific resin B (ABS Styrene resin such as resin or polycarbonate resin), and the other of the specific resins A and B as the secondary side resin of the second shot, and the primary side resin molding portion 6 of the first shot. In place, protrusions such as ribs which are deformed during the second shot injection molding and remain inside the secondary resin molding portion 9, The injection molding method according to claim 1, wherein the first shot is made of resin on the primary side. 4. A resin molded product is used as a key top, and a secondary side resin isolation portion 12a surrounded by a primary side resin molded portion 11 representing a character, number or figure is formed on a part of the letters, numbers or figures. Exists and first shot 1
Injection molding of the primary resin molded portion 11 representing characters, numbers or figures is performed by the resin on the secondary side, and the outer resin molding of the secondary resin that surrounds the periphery of the primary resin molded portion 11 by the resin on the secondary side of the second shot. In the two-color molding method in which the part 12 and the isolated part 12a of the secondary resin are injection-molded, the specific resin A (polyacetal resin, polyamide resin or polypropylene resin) and the specific resin B (ABS are used as the primary side resin of the first shot. Styrene resin such as resin or polycarbonate resin), and the other of the specific resins A and B as the resin on the secondary side of the second shot, in the space 22d for forming the isolated portion of the secondary resin. At the protruding position, a protrusion such as a rib that is deformed at the time of injection molding of the resin on the secondary side of the second shot is provided for the first shot. Injection molding method according to claim 1, characterized in that previously molded by the following side of the resin.