JPH11235763A - Automotive thermoplastic extrusion molding and method for processing terminal thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To finish the terminal of an automotive extrusion molding so that its appearance is satisfactory by thermally melting the end face of the molding with a spongelike foamed layer consisting of a thermoplastic material to make the end face a skin layer. SOLUTION: An elastomer which is thermoplastic and thermally fusible is used as a material for a weather strip 1. Further, the elastomer is extrusion- molded in one piece in such a manner that a cylindrical main seal part 2, a tonguelike seal lip part 3 and a fitting part 4 are continuously integrated. The molding is of such a construction that the entire weather strip 1 including the main seal part 2 and the seal lip part 3 is a spongelike foamed layer and the periphery excepting a cut end face 5 is covered with a skin layer 6 formed during extrusion molding. After that, the weather strip 1 is cut using a hot cutter H and the cut end face 5 is thermally fused to be solidified and thus the skin layer 6 is formed on the cut end face 5. Consequently, the appearance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruded product such as a weather strip for an automobile using a thermoplastic material such as a thermoplastic elastomer (hereinafter sometimes referred to as "TPE") or a thermoplastic resin and the like. It relates to a terminal processing method.

[0002]

2. Description of the Related Art As shown in FIG. 8, a weather strip 100 attached to a door opening of an automobile has a cylindrical main seal portion 102, a tongue-shaped seal lip portion 103, and an attachment fitted to a retainer. It is generally known that they are provided with a portion 104 and are integrally formed by extrusion molding of rubber or the like. The main seal portion 102 is interposed between the door and the body when the door is closed to seal these gaps, and is formed of a sponge-like foam layer together with the seal lip portion 103 to improve flexibility and the like. ing.

By the way, these weather strips 100
For the terminal treatment of the foamed extruded product such as, for example, a method of cutting off the end face 105 as shown in FIG. 8, a method of sealing and closing the terminal by die molding, or a method of joining the terminals, There is a method of closing or joining the terminals with an adhesive.

FIG. 9 shows a conventional method of sealing and closing the end of an extruded product by a molding section 107. The end of the extruded product is set in a mold, and rubber is newly injected and closed. The terminal is sealed by vulcanization bonding with the molded part 107 thus formed.

FIG. 10 shows a conventional method of sealing the end of an extruded product by using an adhesive, and deforms the cylindrical main seal portion 102 so as to crush it.
9 seals and seals the overlapping cylindrical inner surfaces 108.

FIG. 11 shows a method of joining the terminals of a conventional extruded product, and the extruded product 10 is inserted into a mold.
0 terminal is set, rubber is newly injected, and the molding section 1 is formed.
They are joined by vulcanization adhesion of 10.

[0007]

However, any of the above terminal processing methods has the following drawbacks.
First, as shown in FIG. 8, when the end face 105 of the extruded product 100 such as a weather strip is cut off,
There are difficulties such as poor appearance and poor water absorption. That is, each seal portion 102 of the weather strip 100,
The foamed layer forming the surface 103 has a skin layer 106
Can be extruded in a state of being covered with, but the sponge portions of the foam layers of the seal portions 102 and 103 are easily seen from the cut end surface 105 of the terminal, and the appearance is poor. Further, there is a problem that water is easily sucked into the weather strip from the foamed surface, and oozes into the vehicle when the door is closed.

For this reason, as shown in FIG. 9, a method of adding another terminal forming part 107 to the cut end face 105 of the extruded product 100 or bonding the crushed terminal with an instant adhesive 109 as shown in FIG. However, in the former case, the man-hour, the cost of the rubber injection machine and the mold are increased, and the appearance of the molding part 107 is different from that of the extrusion molding part 100. In the latter, there is a problem that the adhesive is adhered to other portions and the quality is unstable, and the number of steps is increased.

On the other hand, as shown in FIG. 11, in the processing method of joining the terminals to each other by the molding section 110, a mold and a rubber injection machine are required, which leads to an increase in cost and an extrusion molding with the molding section 110. The color of the part 100 is different, and the appearance is not good.

[0010]

SUMMARY OF THE INVENTION In view of the above, the inventors of the present invention have proposed, in order to reduce costs and improve the appearance of extruded products for automobiles and their terminal treatment methods, to use these extruded products as materials. The focus was on using a thermoplastic material such as a thermoplastic elastomer (TPE) or a thermoplastic resin instead of rubber. Unlike rubber, a thermoplastic material has the property that the steps of heating and melting and solidifying by cooling can be repeated, and that fusion bonding is also possible. In particular, TPE
It is known that at room temperature, it exhibits rubber elasticity similar to vulcanized rubber, and can be easily plasticized and molded at high temperatures. Moreover, unlike the case of rubber, there is an advantage that rubber does not have, such as recyclability.

The present inventors have paid attention to the properties of these thermoplastic materials such as TPE, and if this is used to terminate the end of an extruded product such as a weather strip, a new material such as rubber can be obtained. It was found that there was no need to inject and the appearance of the terminal was improved. The method of terminating three thermoplastic extruded products will be described below.

First, the first terminal treatment method is a method in which an end face of an extruded product for automobiles having a sponge-like foamed layer made of a thermoplastic material is hot-melted to form a skin layer. Thereby, the skin layer can be easily formed, and the appearance and the water absorption resistance can be improved. In this case, there is a method in which the end face is pressed against a hot press or the like after the terminal is cut to perform hot melting. However, forming the skin layer by hot melting simultaneously with cutting can simplify the skin layer forming process. There are various methods for performing cutting and melting at the same time, and examples thereof include laser cutting and a method using a hot cutter (heated blade tool).

As the thermoplastic material, thermoplastic resin or TP
Any of E may be used, but it is particularly effective to use TPE which exhibits rubber-like elasticity similar to that of rubber and which is also used as a substitute for rubber for automobile parts. Extruded products do not need to be entirely foamed,
What is necessary is just to form a foam layer in at least one copy. For example, in a weather strip, a case where a mounting portion is a solid layer and a sealing portion is a foam layer is exemplified. In addition, as an extruded product for an automobile, it is needless to say that it can be applied not only to a weather strip but also to an opening trim, various moldings, and the like. These points are common to the second terminal processing method and the third terminal processing method described later.

The second terminal treatment method is a method in which the end of the cylindrical hollow portion of the thermoplastic material is thermally deformed by a hot press to close the hollow portion, and the thermoplastic material is melted and deformed by the hot press to close the hollow portion. Because of the blockage, the blockage can be performed without supplying new material, and the appearance is improved. Furthermore, even if the hollow portion is made of a foam material, it can be solidified by melting to form a skin layer on the end face, so that the hollow portion can be closed and the water absorption resistance can be increased.

[0015] In this case, the hot press uses a simple type heat press to crush only the hollow portion from above and below to deform it flat (see Fig. 4), or use a hot press mold to remove the entire terminal. Any of the methods of inserting into a mold press and applying pressure and heating to perform melt deformation (see FIG. 5) can be adopted. In particular, it is preferable that the entire terminal is melted and deformed by being inserted into a mold press in terms of appearance.

Further, as the cylindrical hollow portion, a hollow seal portion of a weather strip which can be elastically contacted with a door or the like can be exemplified. However, the present invention is not limited to this and can be applied to a hollow mounting portion. Alternatively, the present invention can be applied to various extruded products for automobiles having a hollow portion. Further, these materials can be applied irrespective of whether they are foam materials or not, unlike the first terminal treatment method.

The third terminal processing method is a method in which the terminals of an extruded product for automobiles made of a thermoplastic material are butted together and are welded and joined. Unlike rubber, in the case of thermoplastic, the ends are butted and melted (including softening)
It is more advantageous than rubber in that it can be easily joined just by doing.

The butt surface in this case may be an end surface perpendicular to the extrusion direction of the extruded product, but it is preferable that the butt joint area be larger since the joining force increases. As a method of increasing the bonding area, a method of diagonally cutting the ends of the extruded product (see FIG. 7A),
A method of cutting the terminals into a substantially V-shape that can be fitted to each other (see FIG. 7B) and a method of cutting the terminals into a stepped shape that can be fitted to each other (see FIG. 7C) can be exemplified. .

[0019]

Embodiments of the present invention will be described below with reference to the drawings. Each of the drawings shows an example in which the present invention is applied to a weather strip as an extruded product for automobiles. A first terminal treatment method is a method of forming a skin layer on an end face, and a second terminal treatment method. A method for sealing terminals will be described as a method, and a method for bonding end faces will be described as a third processing method.

[First Terminating Method] FIG. 1 shows a method of cutting a terminal of a weather strip using a hot cutter and simultaneously melting the terminal to form a skin layer. The weather strip 1 is made of an elastomer (TPE) having thermoplasticity and heat fusibility as its material, and has a cylindrical main seal portion 2, a tongue-shaped seal lip portion 3, a body and a retainer ( (Not shown) and the mounting portion 4 to be continuously extruded and integrally formed.

In this embodiment, the entire weather strip 1 including the main seal portion 2 and the seal lip portion 3 is formed of a sponge-like foam layer. It is covered by a skin layer 6 formed at the time of molding.

The skin layer 6 is formed by cutting with a hot cutter (hot cutting blade) H so that the cut end faces 5 of the seal portions 2 and 3 and the mounting portion 4 are thermally melted.
The skin layer 6 is formed by solidification as shown in FIG.

The skin layer 6 can be formed by cutting the weather strip with a normal blade and then pressing a heated press or the like against the cut end face. Then, since the skin layer 6 is formed at the same time as the cutting, it is effective in that the process can be simplified.

FIG. 2 shows a laser cut L, and a cut end face L1.
FIG. 3 is a perspective view showing an embodiment in which a skin layer 6 is formed in FIG.
Indicates an end face cut by this. In this example, CO 2 gas or helium / neon gas is used as a medium of the laser oscillator 7 and cut and melted at a temperature of 200 ° C. to 400 ° C. By this laser cutting,
As shown in FIG. 3, the skin layer 6 is formed on the cut end surface.

[Second Terminal Processing Method] FIG. 4 is a diagram showing a method of closing a terminal using a simple heat press. The extruded weather strip 1 has the same configuration as that used in the first terminal processing method, as shown in FIG. In this embodiment, as shown in (B), the cut portion of the cylindrical main seal portion 2 is hot-pressed by a simple hot press P including a pair of upper and lower hot plates P1 and P2 so that the tube is crushed. While deforming flat,
As shown in (C), the cylindrical inner surfaces 9 overlapping by this deformation are thermally fused to each other to close the terminal.

Although the closing of the terminal by the hot press P is performed only on the seal portion 2, the hollow portion 4 a of the mounting portion 4 may be simultaneously closed by simultaneously thermally deforming the mounting portion 4. This terminal processing method can also be used for a weather strip having only a tongue-shaped seal portion such as the seal lip portion 3. Further, in the above embodiment, the weather strip 1 is cut by a normal cutter, but the hot cutter H shown in FIG.
After forming the skin layer 6 on the end face by performing the laser cutting shown in (1), closing the terminal by the hot press P is an effective treatment method from the viewpoint of appearance and water absorption resistance.

FIG. 5 is a diagram showing a method of closing a terminal and molding it into a predetermined shape using a mold heat press. The mold press 10 includes an upper mold 10a and a lower mold 10b whose mold temperature is set to 120 ° C. to 150 ° C.
Although 0b is formed in a plane so as to match the bottom surface of the mounting portion 4, a cavity surface 11 having a semi-conical shape is formed in the mold surface of the upper mold 10a according to the closed shape. The terminal portion of the weather strip 1 is inserted into the mold, the upper die 10a is closed, and the pressure is heated for 5 to 10 seconds to melt and deform the terminal portion. The part 12 is formed.

By adopting such a terminal processing method, a good-looking terminal closing portion 12 can be obtained without supplying new material. Further, since the end of the weather strip to be inserted into the mold press 10 only needs to be directly inserted after being cut by a normal cutter, the processing method is also simplified.

[Third Terminal Processing Method] FIG. 6 shows a processing method of joining the terminals of the weather strip using the joining jig 14. The joining jig 14 is composed of upper and lower joining dies 14a and 14b each having a concave portion having the same cross section as that of the weather strip, and has a length in the extrusion direction of 30 to 50 mm.

When joining the ends of the weather strip 1, the end portions are inserted into the joining dies 14a and 14b, the ends of the both ends are butted, and the end faces are pushed out in the pushing direction by 10 to 5 mm.
0 g of pressure is applied, and the mold temperature is set at 120-150 ° C. for 10
By heating for ~ 20 seconds, the joining surfaces are melted and welded together.

In this case, as the contact area of the joining portion 16 is larger, the joining force is improved. FIG. 7 shows an end face shape for increasing the bonding area. FIG. 3A shows an oblique 16a end surface.
(B) shows an example in which the terminal is cut into a shape having a substantially V-shaped concave portion and a convex portion 16b which can be fitted to each other, and FIG. Step shape 16
Examples of c are shown below.

[0032]

As is apparent from the above description, according to the present invention, by utilizing the properties of a thermoplastic material such as TPE, by heating and melting at the same time as cutting, the end face of a foam extruded molded article that has not been cut off can be obtained. Even if a skin layer is formed, the appearance and the water absorption resistance are also improved. In addition, if a method of closing the hollow part of the extruded product by a hot press or a method of thermally welding the terminals using a joining jig is adopted, it is possible to perform good-looking terminal processing without supplying new material. Become.

[Brief description of the drawings]

FIG. 1 is a process chart showing a weather strip terminal processing method using a hot cutter according to a first embodiment of the present invention;

FIG. 2 is a perspective view showing a terminal processing method by laser cutting.

FIG. 3 is a diagram showing an end face similarly cut;

FIG. 4 is a diagram showing a method of closing a terminal using a simple heat press.

FIG. 5 is a diagram showing a method of closing a terminal using a mold heat press.

FIG. 6 is a diagram showing a terminal processing method for joining terminals using a joining jig.

FIGS. 7A, 7B, and 7C are diagrams showing a technique for increasing the bonding area.

FIG. 8 is a perspective view of a conventional cut weather strip.

FIG. 9 is a perspective view showing a terminal treatment of a weather strip by conventional molding.

FIG. 10 is a perspective view showing a conventional terminal treatment of a weather strip by bonding.

FIG. 11 is a perspective view showing a terminal treatment of a weather strip by conventional joining.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Weather strip 2 Main seal part 3 Seal lip part 4 Attachment part 5 Cutting end surface 6 Skin layer 7 Laser oscillator 10 Type heat press 14 Joining jig P Simple heat press H Hot cutter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 31:30 (72) Inventor Tomohito Ueda 1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka Toyo Tire & Rubber Co., Ltd.

Claims (11)

[Claims] 1. An end treatment method in which an end face of an extruded product for an automobile having a sponge-like foam layer made of a thermoplastic material is heat-melted to form a skin layer. 2. The extruded product is hot-melted simultaneously with cutting by laser cutting, and its end surface is used as a skin layer.
Terminal processing method as described. 3. The terminal treatment method according to claim 1, wherein the extruded product is hot-melted simultaneously with cutting by using a hot cutter, and an end surface thereof is used as a skin layer. 4. A terminal treatment method for an extruded product made of a thermoplastic material and having a cylindrical hollow portion, wherein the terminal of the hollow portion is thermally deformed by a hot press and closed. 5. A terminal treatment method in which terminals of an extruded product for an automobile made of a thermoplastic material are joined to each other by abutting and heat welding. 6. The terminal processing method according to claim 5, wherein after the terminals of the extruded product are cut obliquely, the terminals are butted and welded together to join. 7. The terminal processing method according to claim 5, wherein the extruded products are cut into a substantially V-shape which can be fitted to each other, and then the cut end faces are joined by heat welding. 8. The terminal processing method according to claim 5, wherein the extruded products are cut into a stepped shape that can be fitted to each other, and then the cut end faces are joined by heat welding. 9. An automobile weather strip in which the extrusion-molded article is formed by integrally extruding a mounting portion attached to a peripheral edge of a door opening of an automobile and a hollow seal portion elastically contactable with the door. The terminal processing method according to claim 1. 10. The terminal treatment method according to claim 1, wherein the thermoplastic material is a thermoplastic elastomer. 11. A thermoplastic extruded product for automobiles obtained by the terminal treatment method according to any one of claims 1 to 10.