JP3321022B2 - Die structure for compound extrusion of extruder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die structure for an extruder, and more particularly to an improved die structure for a composite extrusion in which a coating liquid or a paint made of a thermosetting material is applied to the surface of a molded product simultaneously with extrusion. About.

[0002]

2. Description of the Related Art A long and the same cross-sectional shape such as a weather strip for automobiles and a glass run is generally formed by extrusion molding of rubber or synthetic resin. Paint may be applied. As an example, in a glass run having a substantially U-shaped cross section that slidably seals an end surface of a window glass of an automobile, a sliding surface is reduced on a bottom surface in contact with the window glass and inner wall surfaces of both seal lips to reduce sliding resistance and improve durability. In order to achieve this, a coating liquid such as polyurethane is applied.

It is naturally inefficient to apply such a liquid in a separate step after extrusion. In view of this, composite extrusion molding that enables the application of this liquid to be performed simultaneously with extrusion has been employed. In this composite extrusion molding, as described in Japanese Patent Publication No. 7-64006, a main die in which a material passage having a shape corresponding to a desired molded product shape is formed as a die structure,
A coating die which is superposed on the outside of the main die, wherein the coating die is located within a range corresponding to a desired liquid application portion of the extruded product, and a position of a passage inner wall surface of a material passage of the main die. And a side wall surface close to the shape of the molded product so as to have a slight step, and a liquid discharge port is formed in the side wall surface so as to discharge the coating liquid toward the surface of the extruded product. ing. Therefore, while sending a coating liquid such as a coating liquid from the liquid discharge port of the coating die,
By extruding through the main die, extrusion and application to a desired site can be performed simultaneously and continuously.

[0004]

However, in the above-mentioned conventional die structure, the liquid discharge port of the coating die is heated by the heat transmitted from the main die to the coating die or the heat transmitted from the extruded molding material to the coating die. The temperature in the vicinity tends to rise, and when a thermosetting coating liquid is used, a thermosetting reaction occurs near the liquid discharge port, and the coating liquid gels and the liquid discharge port is partially clogged. In addition, there is a problem that the coating thickness becomes non-uniform and coating unevenness easily occurs.

[0005] For example, when a coating liquid composed of polyurethane is applied to the surface of a glass run formed by extruding a rubber material, the main die is at about 90 ° C. In addition, the coating liquid composed of polyurethane is 4
The temperature of the coating die is supplied to the coating die while being kept at about 5 to 50 ° C., and immediately after the start of the operation, the temperature of the coating die itself is close to this. Temperature rises to about 80 ° C. Since the polyurethane starts to cure at about 60 ° C., it is easily heated and gelled while passing through the coating die.

[0006]

Means for Solving the Problems] Therefore, the present invention, cold
By using a cooling fluid made of water, a rise in the temperature of the coating solution is avoided, and the above-mentioned uneven coating is prevented from occurring.

That is, the present invention provides a main base, which is attached to a tip end of an extruder and has a material passage formed in a shape corresponding to a desired shape of a molded product, and is disposed outside the main base. In addition, in a range corresponding to a desired liquid application site of the extruded product, the extruded product has a side wall surface close to the shape of the molded product so as to have a slight step with respect to the inner wall position of the material passage of the main die, and A coating die having an opening formed so that the coating liquid is discharged toward the surface of the extruded product on the side wall surface, and a coating liquid made of a thermosetting material is extruded from the main die. In a composite extrusion die structure of an extrusion molding machine adapted to be applied to the surface of a molded article, a cooling plate is interposed between the main die and the coating die, and the cooling plate is Molding extruded from die There with moldings passage can pass is formed through, the interior of the cooling plate,
It is characterized in that a cooling passage is formed so that cooling water flows without contacting the molded article . In this configuration, the cooling water flows through the cooling passage formed in the cooling plate. Since the cooling plate is interposed between the main die and the coating die, the cooling water
Insulation is provided between the main base and the coating base to suppress the transfer of heat from the main base to the coating base, and at the same time, the coating base is cooled and its temperature is kept low.

[0008] In the second aspect, the cooling passage is recessed in a joint surface of the cooling plate with the main base, and is formed as a passage between the cooling plate and the surface of the main base.

That is, the main die, the cooling plate, and the coating die each have a plate shape, and are used by being overlapped with each other. The cooling passage is formed as a concave portion on one surface of the cooling plate, and becomes a passage when combined with the main base.

[0010]

[0011]

Further, in the invention according to claim 3 , the cooling passage is formed in a range including the projected shape of the liquid supply passage in the coating die.

Thus, the liquid supply passage leading to the liquid discharge port of the coating die is reliably cooled. Therefore, the amount of heat received while the coating liquid flows through the liquid supply passage of the coating die is reduced, and gelation of the coating liquid is suppressed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

This embodiment is an example in which the present invention is applied to extrusion molding of a glass run 31 for automobiles having a substantially U-shaped cross section made of rubber as shown in FIG. 8, and a bottom portion 32 contacting a window glass (not shown). The coating liquid 35 made of polyurethane is applied to the central part surface of the substrate and the surfaces of the left and right seal lips 33 and 34, respectively.

FIG. 1 shows a base of a die structure to which the present invention is applied .
FIG. 3 is a cross-sectional view showing a reference example including the basic configuration,
Based on this, the basic configuration will be described. A disc-shaped main base 2 is attached to the tip of the cylinder barrel 1 of the extruder, and a semicircular coating base 3 is provided on the front surface, that is, the outlet side of the main base 2.
Further, between the main base 2 and the application base 3, a cooling plate 4 having a disk shape like the main base 2 is interposed. These three are closely overlapped with each other and are firmly fixed to each other.

The main base 2 comprises a first plate 2a located on the outside and a second plate 2b located on the inside. The first plate 2a has a desired molded product shape, that is, a cross-sectional shape of the glass run 31 described above. A material passage 5 having a shape corresponding to the shape is formed through. In addition, the second plate 2
A tapered inlet 6 is formed in b to guide the plasticized material into the material passage 5. Therefore,
The rubber material sequentially pressurized and supplied from the cylinder barrel 1 of the extruder by a screw (not shown) is
Is extruded through the material passage 5 in a predetermined shape.

The coating die 3 is, as shown in FIG.
The center of the lower edge is cut out substantially corresponding to the cross-sectional shape of the glass run 31 so as to allow the molded product extruded from the main base 2 to pass therethrough. Then, the application site of the coating liquid 35 of the glass run 31, that is, the left and right seal lip 3
Along the surfaces 3 and 34 and along the bottom 32, a side wall surface 7 parallel to the extrusion direction is provided. The side wall surface 7 is accurately processed so as to have a slight step (for example, about 0.1 mm) with respect to the inner wall surface of the material passage 5 of the main base 2. FIG. 2 shows the back surface of the coating die 3 joined to the cooling plate 4, as shown in FIG.
A liquid supply passage 8 is formed in a substantially sector shape on the back surface of the coating die 3, and the tip thereof is opened as the liquid discharge port 8 a on the side wall surface 7. Specifically, the liquid supply passage 8 and the liquid discharge port 8a are respectively formed corresponding to three application portions. A liquid inlet 9 is connected to an upstream end of the liquid supply passage 8. This liquid inlet 9
Penetrates the coating die 3 and is provided with a liquid supply pipe 10 (FIG. 1).
See). In this embodiment, two liquid inlets 9 are provided at two places, and two liquid supply passages 8 are connected to one of them.

The liquid supply pipe 10 is connected to a supply pump (not shown), and a polyurethane coating liquid is supplied at a predetermined pressure. Therefore, immediately after the glass run 31 is extruded, the coating liquid is continuously applied by passing through the coating die 3.

The cooling plate 4 interposed between the main base 2 and the coating base 3 is made of metal like the two bases 2 and 3, and as shown in FIG. A molded product passage 11 through which a molded product extruded from the main base 2 can pass is formed through the center portion. In this example,
The molded product passage 11 has a cross section substantially equal to the material passage 5 of the main die 2, but may have a shape slightly larger than the material passage 5. A cooling passage 12 is formed inside the cooling plate 4 so as to surround the molded product passage 11. The cooling passage 12 is formed as a concave portion on the back surface of the cooling plate 4, that is, the joint surface with the main base 2, and is formed in a passage shape between the cooling plate 12 and the surface of the main base 2. Have been. The cooling passage 12 is formed on substantially the entire surface of the disk-shaped cooling plate 4, and is formed in the molded product passage 11 so as to leave a constant thickness around the molded product passage 11. They are formed close to each other. Therefore, the cooling passage 12 extends in a range covering the projected shape of the liquid supply passage 8 in the coating die 3. In addition, air inlets 13 are formed at two upper and lower locations 180 ° apart from the cooling plate 4,
A plurality of air outlets 14 are formed on the side of the cooling plate 4. As shown in FIG. 1, the air inlet 13 is connected to an air pump (not shown) via an air introduction pipe 15, and the pump is used to feed cooling air. Further, the cooling passage 12
, Specifically, a surface serving as a bottom surface of a concave portion provided from one surface of the cooling plate 4 is formed as a corrugated surface having a triangular cross section. In other words, the concave grooves 12a having a triangular cross section are formed in parallel at regular intervals. The concave groove 12a is formed along a direction orthogonal to a line connecting the pair of air inlets 13. By providing such an uneven surface, the contact area with the cooling air increases, and the cooling efficiency improves.

[0021] Thus, the cooling air flowing from the air inlet 13 flows through the cooling passage 12 as indicated by an arrow in FIG. 3,
Thereby, the vicinity of the molded article passage 11 is cooled. Further, since an air layer is formed over substantially the entire surface of the cooling plate 4, the space between the main base 2 and the coating base 3 is insulated,
The amount of heat transmitted from the main die 2 to the coating die 3 is reduced.
In particular, the liquid supply passage 8 reaching the liquid discharge port 8a of the coating die 3
The liquid supply passage 8 is reliably cooled because the cooling passage 12 is widened in a range covering the liquid supply passage 8. Therefore, the coating liquid is not heated while flowing through the liquid supply passage 8 of the coating die 3, and the gelation of the coating liquid and, consequently, the clogging of the liquid discharge port 8a are suppressed.

Next, FIGS. 4 and 5 show a second reference example . Examples of this are the cooling plate 4, there is miniaturized to Ryakuhan circular like the coating die 3, with the molded product passage 11 is notched formed on its lower edge center portion, in the interior , A cooling passage 12 is formed. This cooling passage 12 is also formed as a concave portion on the back surface of the cooling plate 4, that is, the joint surface with the main base 2, and is formed in a passage shape between the cooling passage 12 and the surface of the main base 2. It is configured. The cooling passage 12 is formed on substantially the entire surface of the cooling plate 4.
In the range covering the projected shape of the liquid supply passage 8 in FIG. Further, in this embodiment, a single air inlet 13 is formed on the upper part of the cooling plate 4, and a plurality of air outlets 14 are formed on the side of the cooling plate 4. . Further, the bottom 32 of the glass run 31
The air outlet 16 is formed in a portion corresponding to the air outlet 17 so that the cooling air does not stay.
Is communicated through. In this embodiment, an inclined surface 12b is provided on the inner wall surface of the cooling passage 12.
The air inlet 13 is connected to an air pump (not shown) via an air introduction pipe 15.

Therefore, the cooling air flowing from the air inlet 13 flows as indicated by the arrow in FIG. 5, and is partially discharged from the air discharge port 14 on the side, and partially discharged to the portion corresponding to the bottom 32. after cooling and Ru is discharged from the air discharge port 16 to the outside.

Next, FIGS. 6 and 7 show an embodiment of the present invention using the cooling water as a cooling fluid, above
The differences from the reference example will be described. The cooling plate 4 of this embodiment has a substantially semicircular shape similarly to the above-mentioned second reference example, and a molded article passage 11 is cut out at the center of the lower edge thereof. Inside, a cooling passage 12 is formed. This cooling passage 12 is also formed as a concave portion on the back surface of the cooling plate 4, that is, the joint surface with the main base 2, and is formed in a passage shape between the cooling passage 12 and the surface of the main base 2. It is configured. The cooling passage 12 is formed on substantially the entire surface of the cooling plate 4, and particularly, the liquid supply passage 8 in the coating die 3.
In the range that covers the projected shape of In addition, a cooling water inlet 21 is formed in an upper portion of the cooling plate 4, and a portion corresponding to a bottom portion 32 of the glass run 31 is
A cooling water discharge port 22 is formed, and communicates with a cooling water outlet 23 opened on the surface on the coating die 3 side through a tunnel-shaped cooling water discharge passage 24. In this embodiment, a projection 25 projecting in an arc-shaped cross section is formed on the inner wall surface of the cooling passage 12 so as to follow an arc concentric with the outer circumference of the cooling plate 4. Cooling water inlet 21
Is connected to a cooling water pump (not shown) via a cooling water introduction pipe 26.

Accordingly, the cooling water flowing from the cooling water inlet 21 is diffused and flows by the projections 25 as shown by arrows in FIG. After passing through the portion corresponding to 32 and cooling the vicinity, it is discharged from the cooling water discharge port 22. Also in this embodiment, the cooling action and the heat insulating action of the cooling water can prevent the temperature of the coating die 3 from rising, and can prevent clogging.

As is clear from the above description, according to the composite extrusion die structure of the extrusion molding machine according to the present invention, the temperature rise of the coating die through which the coating liquid composed of the thermosetting material flows, particularly, The rise in the temperature of the liquid supply passage is suppressed, and clogging due to gelling of the thermosetting coating liquid can be prevented. Therefore, uneven coating due to the clogging does not occur.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the entire die structure showing a first reference example .

FIG. 2 is a sectional view taken along line AA of FIG. 1 showing only a coating die.

FIG. 3 is a sectional view taken along line BB of FIG. 1 showing only a cooling plate.

FIG. 4 is a sectional view of the entire die structure showing a second reference example .

FIG. 5 is a sectional view taken along the line CC of FIG. 4 showing only the cooling plate.

FIG. 6 is a cross-sectional view of the entire die structure showing one embodiment of the present invention.

FIG. 7 is a sectional view taken along the line DD of FIG. 6 showing only the cooling plate;

FIG. 8 is a cross-sectional view of a glass run as an example of a molded product.

[Explanation of symbols]

2 ... Main base 3 ... Coating base 4 ... Cooling plate 11 ... Molded product passage 12 ... Cooling passage 21 ... Cooling water inlet 22 ... Cooling water outlet

Claims (3)

(57) [Claims] 1. A main die which is attached to a tip of an extruder and has a material passage having a shape corresponding to a desired shape of a molded product formed through the main die. The main die is disposed outside the main die.
In the range corresponding to the desired liquid application site of the extruded product, the extruded product has a side wall surface which is close to the shape of the molded product so as to have a slight step with respect to the position of the inner wall surface of the material passage of the main die. A coating die having a liquid discharge opening formed so as to discharge the coating liquid toward the surface of the extruded product, wherein the coating liquid made of a thermosetting material is extruded from the main die. In a composite extrusion die structure of an extrusion molding machine adapted to be applied to a product surface, a cooling plate is interposed between the main die and the coating die, and the cooling plate is with extruded molded articles molded article passage can pass is formed through, the interior of the cooling plate, molding
A composite extrusion die structure for an extrusion molding machine , wherein a cooling passage is formed so that cooling water flows without contacting a product . 2. The cooling passage is connected to a cooling plate .
2. A composite extrusion die structure for an extrusion molding machine according to claim 1, wherein the die structure is recessed in a joint surface with the main die, and is formed in a passage shape with the surface of the main die. Wherein said cooling passages, composite extrusion of the extruder according to claim 1 or 2, characterized in that it is formed in a range including the projection shape of the liquid supply path in the coating die Base structure.