JPS5923550B2 - Method for molding long objects made of synthetic resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding a long object made of synthetic resin, which enables a long object having a desired uneven shape to be molded by injection molding, and more specifically to a method for forming a long object made of a synthetic resin by injection molding. Regarding the legal improvement, the purpose is to form the next unit while melting it by the residual heat of the molten material at the rear end which is the part to be melted of the unit molded in the light removal molded unit. A method for molding a long object made of synthetic resin, which can increase the strength of the long object by significantly increasing the strength of the connecting section by integrally forming the connecting section between the single bodies by heat fusion. It is on offer.

Conventionally, as a method for molding a long object having an uneven shape on the surface, Japanese Patent Application Laid-open No. 83150/1983 and Japanese Patent Application Laid-open No. 65/1983 have been used.
No. 257, JP-A No. 49-41450, JP-A No. 49-Sho.
No. 74745 and Japanese Unexamined Patent Publication No. 50-8150 are known inventions, in which a single unit is molded by ordinary injection molding, and the unit is moved so that a part of the unit remains in the mold, This unit is connected to the next unit to sequentially mold a long item of a desired length, but when the unit is connected, the portion remaining in the mold of the previously molded unit is filled with, for example, JP-A No. 48 - No. 831
As in the invention disclosed in Publication No. 50, a protrusion having a spear-shaped cross section is formed, and the next single molding material is poured so as to cover the protrusion, thereby integrally forming a connecting part. As in the invention described in the same publication, the outlet is located in the opposite direction to the moving direction of the previously molded unit, so the injected material does not reach the remaining portion of the previously molded unit in the entire mold. During this time, the melting temperature of the material decreases, and the protrusions of the two parts are simply covered and connected without melting.

Therefore, when the protrusions are buried in material and connected, there are serious problems such as cracks, breakage, or looseness in these parts after the connection.

Further, even when the two units are connected by face-to-face contact as shown in FIG. 12, there is also the problem that this portion may break.

Therefore, in a long object formed by connecting each connecting part in this way, the connection state at the connecting part is weak in terms of strength, and this part may break, break, crack, or peel off of the covered material. There was a fatal flaw.

In any case, in the conventional method of molding this type of long object, the long object has been subject to bending, destruction, cracking, looseness, peeling, etc. at the connecting parts of the long object, and has not been put to practical use.

Focusing on these points, the present invention aims to connect the single bodies by first molding the rear end, which is the part to be melted, when molding the single body, and then injecting the rear end from a material injection port provided on the top surface. Features of a method for molding long objects made of synthetic resin that can guarantee the strength of long objects by melting the material with residual heat and heat-fusing it with the next element to form a strong connection. When the fixed mold and the movable mold are closed, the single body is injection molded so that the rear end as the melted part is formed, and after molding, the movable mold is opened and the mold is at least rearward of the molding position. A molten material injection port is provided on the upper surface of the rear end of the unit to move the unit outward so that the end portion to be melted remains in the cavity, and when the movable mold is next closed. The material injected from the mold flows in one direction opposite to the rear end while melting the melted part remaining in the cavity, so that the rear end and the front end of the next single piece are fused and integrated. After that, the movable mold is opened in the same way as described above to move this single piece to the outside, and this process is repeated one after another to form a long article by arranging a large number of single pieces in a row.

An embodiment of the present invention will be described below regarding a rod having a circular cross section and having through holes formed in the radial direction at equal intervals.

First, in order to carry out the present invention, a molding machine main body 1 consisting of a known injection molding machine, a fixed mold 2 and a movable mold 3 equipped thereon, and a feeding mechanism 4 such as an air cylinder are required.

A female mold 5 having a semicircular cross section is formed in the fixed mold 2 and intersects with the molding machine main body 1, and the molding machine main body is located near the opening of the female mold 5 on the side opposite to the feeding mechanism 4. An injection port 6 for the resin to be pumped out from 1 is open.

Further, at one end of the female mold 5 there is a tip of a feeding mechanism 4 such as a piston rond tip of an air cylinder, and the other end is in an open state.

On the other hand, the movable mold 3 forming the opposite corner to the fixed mold 2 is formed with a male mold 5' opposite to the female mold 5, and a hole protrusion T is formed at an appropriate position.
The drilling protrusion 1 has a length such that its tip can come into contact with the inner surface of the female mold 5 of the fixed mold 2 when the movable mold 3 is closed.

Next, I will explain the molding method in more detail.
First, move the movable mold 3 to the fixed mold 2 side and close both molds, then press the resin into the cavity formed by the female mold 5 and male mold 5' from the molding machine main body 1 through the injection port 6. do.

When the resin is press-fitted in this way, the rear end A as the melted part is projected from the body of the unit 8 by the molds 5 and 5' as shown in FIG. 3, and a rod-shaped unit 8 with a circular cross section is formed. Ru.

Moreover, the rod-like single body 8 is penetrated by the perforating projection I.

Next, after molding the single body 8 having the rear end A in this manner, the movable mold 3 is moved backward to open the fixed mold 2 as well, and at the same time, the feeding mechanism 4 is operated and the female part on the fixed mold 2 side is Type 5
The rod-shaped unit 8 inside is inserted into the injection port 6 with its piston rond.
It is forced to be pushed until immediately after passing through.

At this time, as shown in FIG. 4, the pitch is guided so that the part to be melted, which is the rear end A of the rod-like unit 8, remains inside the female mold 5, that is, within the cavity.

After the feeding guide, the piston rod of the feeding mechanism 4 is returned to its original position.

Incidentally, the rod-shaped single body 8 that is fed and guided has a radial through hole 9.
is drilled.

Next, the movable mold 3 is closed by the same operation as described above, and the resin is injected into the injection port 6 formed at the upper surface of the rear end A.
When the resin is press-fitted from the injection port 6, one side of the cavity is divided by the forwarded rod-shaped unit 8, and the other side is divided by the tip of the feeding mechanism 4. In this state, the resin press-fitted from the injection port 6 is As shown in the figure, the surface of the part to be melted, which is the rear end A of the previously molded rod-like unit 8, is melted by the residual heat while flowing in the opposite direction to the rear end A, and the next rod-shaped unit 8 is melted.
At the same time as molding, the front end B and the rear end A of the hardened rod-like unit 8 are thermally fused and become fused and connected as shown in FIG. 4C.

In particular, since the injection port 6 is opened directly above the part to be melted, which is the rear end A, the new material that is successively press-fit melts the upper surface of the part to be melted and flows in one direction on the opposite side of the rear blade end. As a result, as the melting of the melted portion progresses, the next single body is formed, and the state of fusion becomes particularly good.

Moreover, since the material flows only in one direction, the part to be melted is always melted by the residual heat of the new material, which significantly increases the melting effect.

Next, from this state, the movable mold 3 is opened again as shown in FIG. 5, and the rod-shaped single body 8' is pushed out.

After that, by repeatedly closing the movable mold, molding, fusing, opening the movable mold, and pushing the single piece, a series of long through holes in the radial direction were bored at equal intervals as shown in Figure 6. A rod-shaped body C having a circular cross section can be obtained.

Incidentally, the shape of the rear end as the part to be melted is not necessarily limited to the above example, but if it is formed to have a concave cross section as shown in FIG. Not only can a better fused continuous state be obtained, but also a stronger continuous state can be achieved by forming the anchor part 9 in an uneven shape as shown in FIG.

Note that the rear end A of the rod-like unit 8 is formed in an oval shape in cross section in the direction of movement of the molded product having a material flow surface (3) and a welding surface, so that the material melts along the flow surface H during one molding. Molding the next unit 8' while melting the surface, thus forming unit 8, 8'
There is a practical benefit of significantly increasing the strength of the connections between the two.

Moreover, since the surface area of the welding surface is larger than that of the flow surface (2), the melting strength can be further increased, and the occurrence of cracks and distortion between the individual parts can be reliably prevented.

As a result, it has become possible to mold a very thin long article with a length of about 1 m to 5 wrL.

A more important point is that in this embodiment, the position of the injection port 6 is
Since it is provided on the back side 11 opposite to the front side 10 of the unit 80 where the desired uneven shape is formed as shown in the figure opening or FIG. This is extremely useful in the continuous arrangement of the two parts by tightly merging them at the continuous part and preventing gaps.

However, the position of the injection port 6 is not necessarily limited to the front side.

In addition, in the present invention, by varying the operating stroke of the feed mechanism 4, the perforation pitch can be set arbitrarily, and it is possible to perform perforations not only at equal intervals, but also at unequal intervals. Using a mold as shown in FIG. 9, it is possible to mold the surface into an uneven shape or pattern as shown in FIG. 10.

Thanks to this invention, it is possible to mold long decorative boards, decorative sticks, etc. in various shapes.

In addition, in this embodiment, when the movable mold is opened, the molded unit remains on the fixed mold side, so the feeding mechanism for that single unit is attached to the fixed mold side, but when the molded unit is left on the movable mold side In this case, the feeding mechanism is attached to the movable mold side.

In short, all you have to do is mount the unit in a position where it can be sent.

Further, in this embodiment, an extrusion tool such as a piston rond is used as the feeding mechanism, but if the single body is a soft molded body such as polyethylene, it is preferable to feed it by a pulling mechanism from the other direction rather than extrusion.

In the above embodiment, the resin is separated during molding on one side by the rear end of the single piece that has been advanced, and on the other side by the tip of the feeding mechanism in the fixed mold. If the tip of the mechanism is outside the mold, the resin on the other sides is separated by the mold.

Next, another embodiment of the present invention will be described with reference to FIG.

FIG. 11 shows a molding method for forming a synthetic resin layer on the surface of a long core material according to the present invention, and shows the fixed mold 3 of the injection molding machine main body 1 disposed so as to cross the longitudinal direction of the long core material E. Located in the opposing gap when the movable mold 3 is opened, and when the movable mold 3 is closed,
A part of the long core material E is accommodated in the cavity of the mold according to the width interval between the two molds, and resin is injected into the cavity formed on the inner surface between the molds to coat the outer peripheral surface of the core material. A rear end is formed on the resin layer to be formed, and then the movable mold 3 is opened and the core material E is fed by a feeding mechanism to at least the rear end of the resin layer formed on the outer peripheral surface of the core material E. The part A to be melted is moved in the longitudinal direction so that it remains in the cavity, and at the same time the part E' of the next core material E where the resin layer is not formed is moved into the cavity of the mold, and then the movable mold 3 is moved. When the cavity is closed, the material injected from the molten material injection port 6 provided on the upper surface of the part to be melted, which is the rear end A of the resin layer, melts the part to be melted that remains in the cavity, while melting the part to be melted, which is the rear end A of the resin layer. Part A
The resin flows in one direction on the opposite side, and the rear end A and the front end B of the next resin layer are fused and integrated with each other, and the next resin layer is connected to the outer circumferential surface of the elongated core material. It forms a synthetic resin layer like this.

In this way, this embodiment can coat the surface of a long core material with a resin layer having desired irregularities, holes, patterns, etc. at equal or unequal intervals, or coat the surface of a rigid core material such as an iron pipe. The practical effect of forming a resin layer is significant.

Therefore, it has the advantage that materials that can be used for furniture, building materials, etc., such as handrails and supports for stairs, can be produced in large quantities extremely easily and inexpensively.

The temperature during molding is preferably a relatively high temperature, for example, when the material is styrene resin, a temperature of 230 DEG to 250 DEG C. or higher improves the fusion state between the single bodies.

Similarly, the faster the injection speed, the better.

The present invention relates to an improvement in the method of molding a long article made of synthetic resin having a desired shape or pattern such as an uneven surface or holes on the surface. The unit is moved outward so that its rear end remains in the mold, and the molten material is press-fitted from an injection port opened on the upper surface of the rear end of the moving hind limb to form the rear end. The part to be melted is melted and flowed to the opposite side to mold the next unit, and at the same time, the unit is fused and integrated with the front end and the rear end of the unit to form a long item, and the injection port is placed first. Since it is provided inside the rear end of the molded unit, that is, on the top surface, the next unit can be molded while the rear end is melted by the residual heat of the new material that is successively press-fitted, compared to the conventional method. As a result, it is possible to reliably and easily integrate the unit with the next unit, and there are no cracks, breaks, etc. from the connecting part as in the past, and this has led to its successful practical application. be.

Therefore, the continuous part of the long object molded in this way is formed by fusing and integrating the rear end and the front end of the single body, so the continuous part is strong and durable. The strength of the shakumono is significantly greater than that of conventional connections.

Particularly in the formation of long objects, the strength of the connecting portions has been considered to be the greatest difficulty, but the present invention has sufficiently ensured this strength, and the practical effects of this are particularly remarkable.

In particular, when long objects are thin, integral connection, which was extremely difficult with conventional physical connection, is possible by the fusion of the rear end of the present invention, and the connected state is completely free from cracks, peeling, etc. It has become a strong state that will never go away.

Furthermore, if the injection port is located on the back side of the unit, the state of fusion at the continuous portion between the units becomes even tighter, which is extremely beneficial for the integration of the two units.

In addition, this method can be widely used as a manufacturing method for various products such as furniture surrounds and picture frames, and its practical effects are particularly remarkable.

In addition, by coating the surface of a long core material with a synthetic resin layer using this method, it is possible to continuously form a resin layer with a desired uneven shape on the surface of a long core material such as an iron pipe, which was previously impossible. It has advantages such as being able to be formed.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of a device necessary for implementing the present invention. FIG. 2 is a front view of the fixed mold same as above. FIG. 3 is a schematic diagram of a single unit with a molded rear end. Figure 4 A is a front view of the fixed mold during molding, the mouth is a sectional view during molding,
C is a sectional view of the main parts of the decorative material after molding. FIG. 5 is an explanatory diagram of the operation. FIG. 6 is a front view of a long rod-shaped body as an example after molding. FIG. 7 shows the narrow shape of the rear end, and A is a sectional view of the main part. A sectional view of the main part during molding, C is a perspective view after molding. FIG. 8 is a sectional view showing a portion of the anchor formed at the rear end. FIG. 9 is a plan view of a mold as another embodiment. FIG. 10 shows a long object as another embodiment, in which A is a plan view, the mouth is a front view, and C is a sectional view of a main part. FIG. 11 shows another embodiment, in which A is a plan view during molding, and the opening is a perspective view of the molded product. FIG. 12 is a sectional view of main parts showing a conventional example. 2... Fixed mold, 3... Movable die, 4... Extrusion mechanism, 6... Injection port, A... Rear end.

Claims (1)

[Claims] 1 When the fixed mold 2 and the movable mold 3 are closed, a material flow surface H consisting of a face perpendicular to the direction of movement of the molded product is located at a position that has slowly advanced from the material injection port 6 opened on the fixed mold 2 side.
and a fusion surface that is perpendicular to the material flow surface H and parallel to the traveling direction of the molded product to be located directly below the material injection port 6, thereby creating an abbreviated cross-sectional shape on the side of the material injection port 6 in the traveling direction of the molded product. The single body 8 is injection molded so that the rear end A as the part to be melted is formed as much as possible, and after molding, the movable mold 3 is opened and the fusion surface of the rear end A is smaller than the molding position. The unit 8 is moved outward so that the rim is located directly below the material injection port 6, and when the movable mold 3 is next closed, the opposite surface of the fusion surface comes into contact with the movable mold 3, and this state So the single unit 8
The molten material injection port 6 provided above the welding surface of the rear end A of the unit 8 melts the welding surface along the flow surface H of the rear end A of the single body 8 and melts the welding surface. The next unit 8' is molded so that the flow flows in one direction opposite to part A, and the rear end A and the front end B of the next unit 8' are fused together, and then the movable metal is molded in the same manner as above. A method for molding a long article made of synthetic resin, characterized in that a mold 3 is opened, the single body is moved outward, and this process is repeated in sequence to form a long article by arranging a large number of single bodies.