JPH064262B2 - COMPOSITE INJECTION MOLDED BODY, MOLDING METHOD THEREOF, AND COMPOSITE INJECTION MOLDING APPARATUS - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is applied to a composite injection-molded article, a method for molding the same, and a composite injection-molding apparatus, and more specifically, at least two kinds of first resin and second resin. The present invention relates to a composite injection-molded article, a method for molding the same, and a composite injection-molding apparatus.

(Prior Art) In recent years, due to the demand for weight reduction of automobiles, household electric appliances, cameras, containers, etc., parts constituting various machines, devices, etc. are being changed from metal to resin.

Such resin parts are usually formed of a plurality of molded bodies (hereinafter,
(Referred to as a primary molded body) is assembled and configured,
A seal member made of an elastic polymer such as silicone rubber, urethane rubber, or styrene-butadiene rubber in order to maintain the sealing property or impart cushioning property or anti-slip property to the assembly part of the primary molded body (hereinafter, A secondary molded body) is provided.

Conventionally, since such a secondary molded body is molded separately from the primary molded body and then manually assembled to the primary molded body, the assembling accuracy is poor and the assembling man-hour becomes extremely large. There was a flaw.

As a method capable of eliminating such drawbacks, JP-A-60-52322 is known.
JP-A No. 63-104809 or JP-A No. 63-104809 discloses an elastic polymer which is obtained by injection molding to obtain a primary molded article having a concave portion on its surface, and then forms a secondary molded article in the concave portion of the primary molded article. A composite injection molding method of injection filling has been proposed.

(Problems to be Solved by the Invention) According to the composite injection molding method, a composite molded body in which a primary molded body and a secondary molded body such as a seal member are assembled can be molded at a time by injection molding. Therefore, the assembling accuracy can be significantly improved and the assembling man-hour can be remarkably reduced.

However, since the primary molded body is molded by injection molding, the wall surface of the concave portion of the obtained primary molded body is substantially perpendicular to the bottom surface in order to maintain good handling properties such as taking out the molded product from the injection molding machine. It is formed so as to be in a state.

The secondary molded body injection-filled into the recess of the primary molded body does not have any retaining means formed on the wall surface of the recess, so that the secondary molded body is easily pulled out by an external force.

Therefore, in order to firmly fix the secondary molded body to the recessed portion of such a primary molded body, as proposed in the above-mentioned JP-A-63-104809, the bottom surface of the recessed portion of the primary molded body and the two It is necessary to form a reactive elastomer layer and a primer layer between the molded article and the next molded article to bond them together.

Therefore, an object of the present invention is to mold a composite molded body composed of a primary molded body and a secondary molded body by injection molding, and firmly fix the secondary molded body to the recess of the primary molded body without an adhesive layer. Another object of the present invention is to provide a composite injection molded article, a molding method therefor, and a composite injection molding apparatus.

(Means for Solving the Problem) The inventors of the present invention have conducted various studies to achieve the above-mentioned object, and as a result, have pressed the peripheral portion of the recess formed in the primary molded body obtained by injection molding while pressing the recess wall surface. To form an undercut portion by projecting into the concave portion, and then injection-filling the concave portion of the primary molded body with the resin forming the secondary molded body to prevent the secondary molded body from coming off on the wall surface of the concave portion of the primary molded body. The present invention has been completed by finding that the secondary molded body is firmly fixed to the primary molded body because the portion is formed.

That is, the first invention of the present invention is at least two types of first invention.
A resin and a second resin, and a concave portion formed in the primary molded body made of the first resin, and a convex portion fitted in the concave portion formed in the secondary molded body made of the second resin. In the composite injection-molded body configured by the concave and convex engagement by
At least a part of a side wall of the concave portion of the primary molded body is deformed by a pressure applied to a peripheral portion of the concave portion of the primary molded body, and at least a part of a side wall of the concave portion is formed in a mold releasing direction of a mold. An undercut portion is formed so as to project in a recess in a transverse direction with respect to the recessed portion, and a second resin is filled in the recess to form the protrusion of the secondary molded body. It is in the injection molded body.

The second invention of the present invention is at least two types of first invention.
A resin and a second resin, and a concave portion formed in the primary molded body made of the first resin, and a convex portion fitted in the concave portion formed in the secondary molded body made of the second resin. When injection molding a composite injection-molded body configured by engaging with concaves and convexes by means of the above-mentioned method, when the mold for molding the primary molded body is opened, a concave portion having a shape such that the mold can be easily released is formed. A primary molded body having an opening formed in a portion that is to be a joint surface with the secondary molded body is molded, and then, a sidewall that forms the recess by pressing at least a part of a peripheral portion of the recess of the primary molded body, An undercut portion is provided by projecting into a recess in a direction transverse to the mold releasing direction of the mold for molding the primary molded body, and then in the cavity formed by the mold for molding the recess and the secondary molded body. Injection molding of the second resin into the In the composite injection molding method according to symptoms.

Furthermore, the third invention of the present invention is at least two types of first invention.
A resin and a second resin, and a concave portion formed in the primary molded body made of the first resin, and a convex portion fitted in the concave portion formed in the secondary molded body made of the second resin. A composite injection molding apparatus for injection-molding a composite injection-molded body configured by engaging with a concave-convex shape, wherein a pair of primary moldings having a recessed portion formed at a portion to be a joint surface with the secondary molding is formed. And a direction crossing the side walls of the recess by pressing at least a part of the peripheral portion of the recess of the obtained primary molded body with respect to the mold release direction of the pair of molds for molding the primary molded body. A cavity for a secondary molded body is formed between the mold provided with a pressing portion that protrudes into the recess to form an undercut portion, and the housed primary molded body, and the inside and inside of the cavity are formed. The second resin is injected and filled in the recess of the molded body to Lying in the composite injection molding apparatus according to claim comprising a pair of molds for molding the feature.

In the composite injection-molded article according to the first aspect of the present invention, the concave portion formed in the primary molded article is a groove-like concave portion,
A peripheral portion on one side of the opening edge of the groove-shaped recess is pressed, and one of the side walls of the groove-shaped recess projects into the recess over the entire one side of the opening edge to form an undercut portion. Thus, even if the secondary molded body to be fixed to the primary molded body is an elastically deformable secondary molded body made of an elastic polymer such as silicone rubber, they can be firmly connected.

Particularly, the periphery of the opening of the side wall forming the recess formed in the primary molded body is pressed over the entire circumference of the recess opening, and a part of the side wall of the recess projects into the recess over the entire circumference of the opening. The formation of the undercut portion allows the primary molded body and the elastically deformable secondary molded body made of an elastic polymer such as silicone rubber to be connected more firmly.

In the composite injection molding method according to the second aspect of the present invention, the pressing of the peripheral portion of the recess of the primary molded body is performed by the protrusion provided on the mold, or the protrusion formed in advance in the peripheral portion of the recess. The undercut portion can be easily formed in the concave portion of the primary molded body by pressing the portion.

When the concave portion of the primary molded body is a groove-shaped concave portion, the peripheral portion on one side of the opening edge of the groove-shaped concave portion is pressed over the entire one side of the opening edge, whereby the primary molded body and the silicone rubber, etc. The elastically deformable secondary molded body made of the elastic polymer can be firmly connected.

In particular, by performing the injection filling of the second resin while pressing the entire peripheral portion of the recess opening portion of the primary molded body, it is possible to effectively prevent burrs that tend to occur during molding of the secondary molded body.

Further, in the compound injection molding apparatus according to the third aspect of the present invention, a pair of molds for molding the primary molded body, and a mold for molding the primary molded body in which the convex portion is formed around the concave opening portion. Or a pair of molds for molding the primary molded body,
A mold for molding a primary molded body having a convex portion formed around the opening of a concave portion, or of a pair of molds for forming the primary molded body, the mold is opened after the primary molded body is formed. At this time, the mold on the side where the primary molded body remains adhered can be easily combined with the mold in which the pressing portion that forms the undercut portion is provided in the concave portion of the primary molded body, thereby facilitating the primary molding. An undercut portion can be formed in the recess of the molded body.

In this composite injection molding apparatus, one side peripheral portion of the opening edge of the groove-shaped recess is pressed over the entire edge of the opening to a mold that presses the peripheral portion of the groove-shaped recess formed in the primary molded body. By providing a pressing portion for pressing the second resin, or by providing the die for injection filling the second resin with a pressing portion for pressing the entire peripheral portion of the recess opening portion of the primary molded body. Even if the secondary molded body to be fixed to is an elastically deformable secondary molded body made of an elastic polymer such as silicone rubber,
It is possible to easily form the undercut portion capable of firmly connecting the both in the recess of the primary molded body.

The "undercut portion" in the present invention means that at least one portion narrower than the width of the bottom surface of the recess exists in the recess between the recess opening surface and the bottom surface.

(Operation) According to the present invention, by applying an external force or the like to the peripheral portion of the opening of the recess of the preformed primary molding, the wall surface of the recess is projected into the recess to form the undercut portion and the secondary molding is performed. After providing the retaining portion for the convex portion of the body, the second portion is provided in the concave portion.
Since the resin is injection-filled to form the convex portion of the secondary molded body, the concave portion of the primary molded body of the resulting composite injection molded body and the convex portion of the secondary molded body are firmly engaged with each other.

Moreover, when opening the mold for molding the primary molded body,
After molding a primary molded body in which a recess having a shape that allows the mold to be easily released, is molded, the primary molded body is molded by pressing the peripheral portion of the recess opening of the obtained primary molded body. The undercut portion can be formed by projecting the side wall of the recess into the recess in a direction transverse to the mold releasing direction. Therefore, it is possible to easily form the undercut portion, which is difficult to be directly molded by the mold for molding the primary molded body, in the concave portion of the primary molded body, and the primary molded body and the secondary molded body are firmly engaged with each other by concavo-convex. It is possible to easily obtain a composite injection molded product.

Further, the undercut portion of the concave portion of the primary molded body can be easily formed by clamping the mold for housing the primary molded body and the mold having the pressing portion for pressing the peripheral portion of the concave portion of the primary molded body. You can

(Example) This invention is demonstrated using drawing.

FIG. 1 (a) is a perspective view showing an example of the composite injection-molded article of the present invention, and FIG. 1 (b) is a cross-sectional view taken along the line XX of the composite injection-molded article shown in FIG.

In FIG. 1, a secondary seal ring formed by a second resin made of silicone rubber is formed on a flange portion of a primary molded body A made of a first resin made of glass fiber-containing nylon 6 and formed by a second resin made of silicone rubber. A molded body B and a plurality of bolt holes 10 are provided.

A concave portion 3 is formed on the contact surface of the primary molded body A with the secondary molded body B, and the side wall forming the concave portion 3 projects into the concave portion 3 toward the upper side.

Therefore, as shown in FIG. 1B, the cross-sectional shape of the recess 3 becomes wider as the vicinity 4 of the opening of the recess 3 is narrowest and the bottom 4 of the recess 3 approaches from the vicinity 4 of the opening. It is a so-called reverse taper type, and the vicinity of the bottom portion 5 is an undercut portion.

Such a concave portion 3 is filled with a second resin made of silicone rubber, and the second resin filled in the concave portion 3 forms a convex portion of the secondary molded body B.

Therefore, the convex portion of the secondary molded body B is fitted in the concave portion 3 of the primary molded body 1 in which the undercut portion is formed in the vicinity 5 of the bottom portion, and the protruding portion of the concave portion 3 in the vicinity of the opening portion 2 is doubled. The secondary molded body B is firmly fixed to the recess 3 of the primary molded body A because it serves as a retaining portion of the secondary molded body B.

The composite injection molded body shown in FIG. 1 can be obtained by the injection molding method shown in FIG.

That is, first, the primary molded body A in which the recess 13 is formed is
The primary compact A is left in the mold Z, which is one of a pair of molds to be molded [FIG. 2 (a)]. The recess 13 of the primary molded body A remaining in the mold Z is opened on the upper surface of the primary molded body A.

As shown in FIG. 2 (a), the cross-sectional shape of such a recess 13 is a rectangular shape in which the side wall of the recess 13 is substantially perpendicular to the bottom surface, so that it forms a pair with the mold Z for primary molding. The other mold forming the body A can be easily released from the primary molding A when the mold is opened, and the primary molding A can be left in the mold Z.

Next, the mold Y having the protrusion 6 and the cavity 7 for the secondary molded body and the mold Z in which the primary molded body A is left are clamped, whereby the recess 13 of the primary molded body A is obtained.
The peripheral portion of the opening is pressed [Fig. 2 (a), (b)].

By pressing the peripheral portion of the concave portion 13, both side wall surfaces of the concave portion 13 project into the concave portion 13. As shown by the hatched portion 8 in FIG. 2 (b), the degree of this protrusion is larger toward the upper side of the concave portion, so that the sectional shape of the concave portion is deformed into an inverse tapered shape. An undercut portion is formed in the vicinity 5 of the bottom portion of the recessed portion 3 whose cross-sectional shape is changed, and a retaining portion is formed in the vicinity 4 of the opening portion.

Further, the secondary molded body B is a concave portion of the primary molded body A by injecting the second resin into the concave portion 3 and the cavity 7 of the mold Y and then opening the mold Y and the mold Z. It is possible to obtain a composite molded body firmly fixed to No. 3 [Fig. 2 (b), (c)].

When a resin having an extremely low surface tension such as silicone rubber is used as the second resin forming the secondary molded body B as in this embodiment, the second resin has an extremely narrow gap of about 5 μm. Since it also enters, burrs are easily generated around the secondary molded body B.

In this regard, in the present embodiment, the second resin is formed in the recess 3 and the cavity 7 while pressing the peripheral portion of the opening 3 of the recess 3 of the primary molded body A with the protrusion 6 of the mold Y. By injection filling, the sealing property of the entire peripheral portion of the concave portion 3 is significantly improved, so that burrs generated in the peripheral portion of the secondary molded body B can be prevented.

As a method of providing an undercut by pressing the peripheral portion of the recess 13 formed in the primary molded body A remaining in the mold Z, the projection 6 provided in the mold Y shown in FIG. The undercut portion can be formed in the recess 13 by the method shown in FIG. 3 in addition to the method of pressing the peripheral portion of the recess 13 with.

In the method shown in FIG. 3, a convex portion 9 is provided in advance around the opening of the concave portion 13 of the primary molded body A [FIG. 3 (a)], and the concave portion 9 is provided with a cavity for a secondary molded body. It is a method of pressing with the lower surface of the mold Y (FIG. 3 (a),
(B)].

According to this method, the pressure mark remaining on the upper surface of the primary molded body A can be made smaller than that when pressure is applied by the protrusion 6 of the mold Y shown in FIG. 2 [FIG. 3 (b ),
(C)].

The methods shown in FIGS. 2 and 3 may be used in combination,
Examples thereof are shown in FIGS. 4 and 5.

FIG. 4 shows the periphery of the opening of the recess 13 of the primary molded body A,
This is a method in which the convex portion 9 formed in advance around the opening of the concave portion 13 and the protruding portion 6 provided on the die Y are used for double pressing.

Further, FIG. 5 shows a method of pressing each side of the peripheral portion of the opening of the concave portion 13 by the convex portion 9 or the protrusion portion 6 of the mold Y formed in advance on the peripheral portion of the opening portion of the concave portion 13.

Among such pressing methods, the method shown in FIG.
The degree of protrusion of the wall surface of the into the recess can be maximized.

Although the recess 13 has a substantially rectangular cross-sectional shape in the present embodiment, when the mold forming the primary molded body A paired with the mold Z is opened, the primary molded body A As long as it can be easily released, the cross-sectional shape of the concave portion 13 is punched out, tapered, semicircular,
It may have any shape such as a quadrangle or a semi-elliptical shape.

The cross-sectional shape of the protrusion 6 provided on the mold Y may be wedge-shaped, semi-circular, semi-elliptical, trapezoidal, or the like, and the wedge-shaped peripheral portion of the recess 13 of the primary molded body A is particularly preferable. It is preferable that the protrusions 6 bite into the recesses and the wall surfaces of the recesses can be easily protruded.

Further, similarly, the cross-sectional shape of the convex portion 9 formed in advance around the concave portion 13 of the primary molded body A can be any shape such as a wedge shape, a semicircle, a semielliptic shape, and a trapezoid.

The protrusions 6 and / or the protrusions 9 may be provided so as to press the peripheral portion of the opening 13 of the recess 13 of the primary molded body A, and at least a part of the peripheral portion of the recess 13 may be provided. You may provide so that it may be pressed. What is essential is that the peripheral part of the recess of the primary molded body A is pressed to project the wall surface of the recess.

In this way, in order to press the peripheral portion of the concave portion 13 of the primary molded body A to transform it into the concave portion 3 having the undercut portion, the mold Y of the primary molded body A remaining attached to the mold Z is retained. The mold Y is to be in close contact except for the surface and its recess.
When the mold and the mold Z are clamped, the wall surface of the recess can be easily projected.

As shown in FIG. 6, the mold Y may be provided with an injection hole 11 for injecting and filling a second resin forming the secondary molded body B into the recess and the cavity of the primary molded body A. .

Incidentally, such an injection hole 11 may be provided in a mold different from the mold Y.

FIG. 6 shows a composite injection molding apparatus capable of molding the composite injection molded body of this embodiment.

In the injection molding apparatus shown in FIG. 6, a primary molding injection apparatus 20 and a secondary molding injection apparatus 21 are provided side by side on a machine base 30, and a mold W is provided between a movable platen 24 and a fixed platen 22. , Y, Z
Is provided.

The mold Z is a mold clamping piston 26 that is directly connected to the mold clamping cylinder 27.
The mold Z is bolted to a movable platen 24 which is movable by means of a mold, and the mold Z is connected and clamped with the mold W or the mold Y bolted to the slide plate, or the mold is opened.

The slide plate 25 is slid by the hydraulic cylinder 23 provided on the fixed platen 22, and the mold W or the mold Y is slid to a position where it can be connected and clamped with the mold Z.

In the injection molding apparatus shown in FIG. 6, as shown in FIG. 6 (a), the movable platen 24 is moved rightward by the mold clamping cylinder 27 and the mold clamping piston 26, and the mold Z and the mold W are separated from each other. After the mold is clamped, the injection molding device 30 for primary molding advances and the cavity for primary molding formed by the mold Z and the mold W is injected and filled with molten glass 6 containing glass fiber.

In such molten glass nylon 6 containing glass fibers, solid pelletized nylon 6 resin (containing glass fibers) supplied from a hopper 29 provided on the injection molding device 20 for primary molding is melted in the injection molding device 20 for primary molding. It was done.

After the injection-filled nylon 6 is cooled and solidified and the primary molding injection device 20 is retracted, the movable platen 24 is moved leftward and the mold Z and the mold W are opened. At this time, the primary molded body A remains in the mold Z while the recess 13 opens on the upper surface of the primary molded body A.

Next, the primary molded body A remaining in the mold Z is connected and clamped with the mold Y moved by the slide of the slide plate 25, as shown in FIG. 6 (b).

As shown in FIG. 6 (a), the mold Y is provided with a protrusion 6 on the periphery of a cavity 7 for a secondary molded body, and an injection hole 11 for a second resin made of silicone rubber is provided in the cavity. It is connected to 7.

Further, a recess 40 is provided in the vicinity of the center of the mold Y, and the recess 40 has a structure in which the sprue 33 formed on the primary molded body A is connected to the mold Z as shown in FIG. 6 (b). It is stored when the mold is clamped with the mold Y.

The sprue 33 is made of the first resin filled in the molten resin passage 133 provided between the tip of the nozzle of the primary molding injection device 20 and the cavity for the primary molding when the primary molding A is formed. It is cooled and solidified.

When the mold Z and the mold Y are clamped, the protrusion 6 provided on the mold Y presses the peripheral portion of the opening of the concave portion 13 of the primary molded body A, and the concave portion 13 has a reverse taper shape. It is transformed into the concave portion 3.

The secondary molding injection device 21 advances into the recess 3 and the cavity 7 to inject the second resin made of silicone rubber to mold the secondary molding body B.

The second resin supplies silicone rubber from the pot 31 of the sealing material supply device 28 and supplies a curing agent or the like from the pot 32 to the respective secondary molding injection devices 21, and the secondary molding injection device 2
After the two are mixed in 1, the concave portion 3 and the cavity 7 are injected and filled. The injection-filled second resin cures in the recess 3 and the cavity 7.

Since the second resin is a thermosetting resin, it is necessary to cool the injection device 21 for secondary molding and heat the mold Y to about 120 to 150 ° C. to make the second resin for secondary molding. The recess 3 and the cavity 7 without being cured in the injection device 21.
Can be quickly cured in.

Further, in the temperature range of the mold Y, nylon 6 which is a thermoplastic resin used as the first resin is not particularly affected.

On the other hand, the mold W that forms the primary molded body A has a temperature of 80% in order to rapidly cool and solidify the first resin, which is a thermoplastic resin.
It is preferable to maintain the temperature at about 90 ° C.

In the apparatus of FIG. 6, the recess 13 formed in the primary molded body A
7 is pressed by the protrusions 6 of the mold Y, but an example is shown in FIG. 7 in which the protrusions 9 formed in advance around the openings of the recesses 13 of the primary molded body A are pressed. Show.

The device shown in FIG. 7 is similar to the device shown in FIG.
This is a horizontal mold device in which the mold Z and the nozzles 120 and 121 move laterally when the mold is clamped and opened, and the vertical movement in the drawing is actually movement in the horizontal direction.

As shown in FIG. 7A, the molten first resin is injected from the nozzle 120 of the primary molding injection device 20 into the cavity for the primary molded body formed by the mold Z and the mold W. A convex portion 9 is formed around the opening of the concave portion 13 of the primary molded body A.

Next, after the mold W and the mold Z are opened, the mold Z in which the primary molded body A having the convex portions 9 remains and the mold Y moved by the movement of the slide plate 25 are By the mold clamping, the convex portion 9 of the primary molded body A is pressed by the lower surface of the mold Y, the cross-sectional shape of the concave portion 13 is deformed into an inverse taper shape, and the concave portion 3 having the undercut portion is formed. Further, the recess 3 and the cavity for the secondary molded body are injection-filled with the second resin to form the secondary molded body B.

The second resin is used in the nozzle 1 of the injection machine 21 for secondary molding.
It is injection-filled from 21 through the injection hole 11 [FIG.7 (b)].

As shown in FIG. 7B, the mold Y is provided with a recess 40 for accommodating the sprue 33 formed in the primary molded body A, and the mold Z and the mold Y are clamped. When the sprue 33
Can be done without cutting.

Further, in the apparatus shown in FIG. 6, the mold W and the mold Y are
Are individually bolted to the slide plate 25, but as shown in FIG. 8, the mold W and the mold Y may be bolted to the slide plate 25 having an integrated structure.

The slide plate 25 may be replaced with a rotary type, and in the rotary type, the molds X and Y rotate and move to a position where they are connected and clamped with the mold Z.

The embodiment described so far is the recess 1 of the primary molded body A.
Although the cross-sectional shape of the concave portion 13 is deformed by pressing the upper surfaces of both side portions of the concave portion 13, the cross-section shape of the concave portion 13 is reduced by pressing the upper surface of both side portions because either side portion or one of the concave portions 13 is thin. An example of the one whose shape cannot be changed will be described.

9 and 10 show the case where one side portion (50 in FIG. 9) forming the concave portion 13 of the primary molded body A is thin and the upper surface thereof cannot be pressed.

In this case, as shown in FIG. 9, by pressing one side peripheral portion of the opening edge of the recess 13 on the upper surface of the side 51 that can be pressed, the undercut portion is recessed in the recess 13. It can be provided over the entire edge of the opening edge 13 on one side.

Alternatively, as shown in FIG. 10, the surface 52 of the mold Y that is in contact with the side portion 50 whose upper surface cannot be pressed is inclined, and the side portion 50 is pressed into the concave portion 13 by this surface 52 while the other side is pressed. By pressing the upper surface of the side portion 51 with the protrusion 6 of the mold Y, the concave portion 13 shown in FIG. 10 can be transformed into the inverse tapered concave portion shown in FIG. 4 and the like.

The method shown in FIG. 9 can be used when the cap 100 having the seal member 220 on the bottom is molded by injection molding as shown in FIG.

That is, the side portions 50, 51 forming the concave portion 13 of the primary molded body
Are thin, and it is impossible to press the upper surface thereof. Therefore, by pressing the upper surface of the other side portion 110, one of the wall surfaces of the concave portion 13 is deformed to form the concave portion 3 having the undercut portion. Can be formed.

Further, as shown in FIG. 12, the method shown in FIG. 10 presses the upper portions of the thin side portions 50 and 51 together into the concave portion 13 by the curved surface 52 of the mold Y to form a concave portion having an undercut portion. It can be 3.

Further, FIGS. 13 and 14 show a case where the secondary molded body B is injection molded between the outer pipe and the inner pipe in the double pipe.

In this case, as shown in FIG. 13, when a part of the inner pipe can be deformed, the bottom vicinity 56 of the rod-shaped protrusion 55 of the mold Y is tapered, and the tapered bottom vicinity 56 causes Part of the inner tube is transformed into the recess 13,
The recess 3 has an undercut portion.

On the other hand, as shown in FIG. 14, when the inner pipe cannot be deformed, the pin 57 provided on the mold Y is projected to deform a part of the outer pipe to provide the undercut portion in the recess 3. You can

The method shown in FIGS. 13 and 14 can be used together as shown in FIG. According to the method shown in FIG. 15, the undercut portion is more surely formed in the concave portion 3.
In addition, it is possible to prevent burrs from being generated when the secondary molded body is injected and filled.

When pressing both sides or one side of the concave portion 13, the pressing may be performed over the entire circumference of the concave portion or a part thereof.

Further, in FIG. 16, the concave portion of the primary molded body A is the large groove portion 13
0 and the small groove portion 13 are two-stage grooves, and only the peripheral portion of the opening of the small groove portion 13 is pressed to form the concave portion 3 having the undercut portion, and then the secondary molded body is formed in the large groove portion 130 and the concave portion 3. The case where the resin to be filled is used for injection filling is shown.

In this case, in FIG. 6, the injection hole 11 provided in the mold Y is separated from the mold Y by a mold Y ′ (not shown).
The injection hole 1 in addition to the molds W, Y, Z
This can be achieved by providing a mold Y'where 1 is provided.

That is, the mold W, first Z, is used to mold the primary molded body A in which the concave portions of the two-step groove shown in FIG. 16 (a) are provided.

Next, as shown in FIG. 16 (b), the peripheral portion of the small groove portion 13 of the primary molded body A that remains attached to the mold Z is pressed by the protrusion 6 provided on the mold Y to form the small groove portion. Only the wall surface portion of 13 is projected into the concave portion to form an undercut portion.

After that, the second resin that forms the secondary molded body B from the injection hole 11 provided in the mold Y'by forming a pair of the mold Y'and the mold Z'is used as shown in FIG. 16 (b). In this way, the primary molded body A and the secondary molded body B can be integrated by injection-filling the concave portion and the cavity.

As described above, in this embodiment, nylon 6 which is a thermoplastic resin is used as the first resin forming the primary molded body A.
Although silicone rubber, which is a thermosetting resin, is used as the second resin forming the secondary molded body B, more resins can be used in the present invention.

For example, a general-purpose resin such as polyester, polyvinyl chloride, polyethylene, or polypropylene can be used as the thermoplastic resin, and an epoxy resin, unsaturated polyester, or the like can be used as the thermosetting resin.

Further, not only the combination of the thermoplastic resin and the thermosetting resin, but also in the thermoplastic resin, the composite molded article is formed by injection molding using a resin incompatible with each other, such as polyester and polypropylene. The present invention can be applied also in this case.

According to the present invention, as shown in FIG. 17, a composite molded body in which a seal member made of an elastic polymer which is a secondary molded body B is firmly fixed to a primary molded body A having a complicated shape is provided. , Can be easily obtained by injection molding.

Although the secondary molded body B shown in FIG. 17 was used as a seal member, it can also be used as a cushion member by utilizing its elasticity, and can also be used as a slip prevention member.

In that case, it goes without saying that the optimum polymer for each member can be appropriately selected.

In this embodiment, the horizontal injection molding machine in which the movable plate 24 and the like move in the left-right direction is used, but the present invention is also applicable to the vertical injection molding machine in which the movable plate 24 and the like moves in the vertical direction. You can

(Effect of the Invention) According to the present invention, a composite molded body in which a secondary molded body such as a seal member, a cushion member, or an anti-slip member is firmly fixed to a primary molded body having a complicated shape It can be easily obtained by injection molding while suppressing the occurrence of

Therefore, the number of steps such as manually assembling the seal member and the like into the primary molded body or removing the generated burrs can be significantly reduced, and the molding process can be extremely simplified.

[Brief description of drawings]

FIG. 1 is a perspective view and a sectional view showing an embodiment of a composite injection-molded article of the present invention, FIGS. 2 to 5 are explanatory views for explaining the composite injection-molding method of the present invention, and FIGS. Explanatory drawing explaining the compound injection molding apparatus of this invention, FIGS. 9-16 is explanatory drawing which shows the other Example of this invention, FIG. 17 is a perspective view which shows the other Example of the compound injection molding of this invention. Each figure is shown. In the figure, A ... Primary molded body, B ... Secondary molded body, 3 ... Recessed portion having an undercut portion, 5 ... Recessed portion formed near the bottom portion of the recessed portion 3, W・ ・ ・ Mold for primary molding A, Y ・ ・ ・ Mold that sticks to mold Z and presses the peripheral portion of the concave portion of primary molding A, Z ・ ・ ・ Primary molding A remains adhered Mold on the side to do.

Claims (15)

[Claims] 1. A recess formed in at least two kinds of a first resin and a second resin, the recess being formed in a primary molded body made of the first resin, and a recess formed in a secondary molded body made of the second resin. In the composite injection-molded body configured by engaging the concave portion and the convex portion that are fitted with each other, the concave portion of the primary molded body is caused by the pressure applied to the peripheral portion of the concave portion of the primary molded body. Due to the deformation, at least a part of the side wall of the concave portion projects into the concave portion in a direction transverse to the mold releasing direction of the mold for molding the primary molded body to form an undercut portion, and in the concave portion, A composite injection-molded article, wherein the second resin is filled to form the convex portion of the secondary molded article. 2. The concave portion formed in the primary molded body is a groove-shaped concave portion, a peripheral portion on one side of an opening edge of the groove-shaped concave portion is pressed, and one side wall of the groove-shaped concave portion has the opening edge. The composite injection-molded article according to claim 1, wherein an undercut portion is formed so as to project into the recess over the entire edge on one side. 3. The periphery of the opening of the recess formed in the primary molded body is pressed over the entire circumference of the opening of the recess, and a part of the side wall of the recess projects into the recess over the entire circumference of the opening. The composite injection-molded article according to claim 1, wherein an undercut portion is formed. 4. A recess formed in at least two kinds of a first resin and a second resin, the recess being formed in the primary molded body made of the first resin, and a recess formed in the secondary molded body made of the second resin. When injection molding a composite injection-molded body formed by engaging concave and convex with the concave portion and the fitted convex portion, a primary molded body opened at a portion to be a joint surface with the secondary molded body Then, the side wall forming the recess by pressing at least a part of the peripheral part of the recess of the primary molded body is recessed in a direction transverse to the mold releasing direction of the mold for molding the primary molded body. An undercut portion is provided by projecting inward, and then a second resin is injection-filled into a cavity formed by the recess and a mold for molding the secondary molded body to mold the secondary molded body. And a compound injection molding method. 5. The composite injection molding method according to claim 4, wherein the peripheral portion of the recess of the primary molded body is pressed by a protrusion provided on the mold. 6. The composite injection molding method according to claim 4, wherein the pressing of the peripheral portion of the concave portion of the primary molded body is performed by pressing a convex portion formed in advance in the peripheral portion of the concave portion. 7. The recess of the primary molded body is a groove-shaped recess, and the peripheral portion on one side of the opening edge of the groove-shaped recess is pressed over the entire one side of the opening edge. The composite injection molding method described. 8. The composite injection molding method according to claim 4, wherein the injection filling of the second resin is performed while pressing the entire peripheral portion of the recess opening of the primary molding. 9. A recess formed in at least two kinds of a first resin and a second resin in a primary molded body made of the first resin, and a recess formed in a secondary molded body made of the second resin. A composite injection molding apparatus for injection-molding a composite injection-molded body, which is formed by engaging concave and convex with the concave portion and the fitted convex portion, wherein the concave portion is provided at a portion to be a joint surface with the secondary molded body. A pair of molds for molding a primary molded body having an opening, and a sidewall of the concave portion by pressing at least a part of the peripheral portion of the concave portion of the obtained primary molded body, a pair of molds for molding the primary molded body. For the secondary molded body, the mold is provided between the mold, which is provided with a pressing portion that projects into the recess in a direction transverse to the mold releasing direction to form an undercut portion, and the housed primary molded body. Forming the cavity and inside the cavity and before the primary molding Composite injection molding apparatus characterized by comprising a pair of molds for molding the second resin injected and filled secondary molded body in the recess. 10. The injection composite molding apparatus according to claim 9, wherein the pressing portion of the mold for pressing the peripheral portion of the recess of the primary molded body is a protrusion. 11. The composite injection molding according to claim 9, wherein the pair of molds for molding the primary molded body is a mold for molding the primary molded body in which the convex portion is formed in the peripheral portion of the concave opening. apparatus. 12. A mold for pressing a peripheral portion of a groove-shaped recess formed in a primary molded body, the peripheral portion on one side of an opening edge of the groove-shaped recess extending over the entire one side of the opening edge. The composite injection molding device according to claim 9, further comprising a pressing portion for pressing. 13. A pair of molds forming a primary molded body, the mold on the side where the primary molded body adheres and remains when the mold is opened after the primary molded body is formed. The composite injection molding apparatus according to claim 9, wherein the compound injection molding apparatus is shared by a mold provided with a pressing part that forms an undercut part in the mold. 14. Among a pair of molds for forming a primary molded body, the mold on the side where the primary molded body adheres and remains when the mold is opened after the primary molded body is formed, The composite injection molding apparatus according to claim 9, wherein the composite injection molding apparatus is shared by a metal mold for accommodating a primary molded body among a pair of metal molds to be molded. 15. The composite injection molding apparatus according to claim 9, wherein the mold for injection filling with the second resin is provided with a pressing portion for pressing the entire peripheral portion of the recess opening of the primary molded body.