JP2002059493A - Automotive weather strip and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the adhesive bonding strength when a channel portion is extruded and then a flange lip is molded as a secondary molding in a door glass run made of a thermoplastic elastomer to integrate the two. . SOLUTION: When extruding a channel portion 6, joint layers 11 and 12 are simultaneously extruded in advance on a portion to be a joint surface with a flange lip 7 and 8. When the pair of flange lips 7 and 8 are molded (injection molded), the bonding layers 11 and 12 are plasticized again due to the thermal influence of the molding material, and the bonding layers 11 and 12 are used to form the channel portion 6. The flange lips 7 and 8 are integrally and firmly bonded to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weather strip for automobiles formed of a thermoplastic elastomer and a method for producing the same, and for example, an extruded portion formed into a long and uniform cross-sectional shape by an extrusion method. The present invention relates to a weather strip having a die forming part integrally formed as a deformed part molded part on a part of the extruded part and a method of manufacturing the same.

[0002]

2. Description of the Related Art As is well known, in a door glass run of an automobile, a rubber material such as EPDM (ethylene propylene rubber) or a soft synthetic resin material represented by an olefin-based or styrene-based thermoplastic elastomer is used. Generally, it is formed. And, for example, in FIGS.
As shown in the figure, a door glass run 31 disposed at a portion along the center pillar of a front door (a right side door is viewed from the vehicle interior side in this drawing) 30 has a door waist from an upper portion thereof. In some cases, a shape whose cross-sectional shape gradually changes toward the lower part on the part side is required. This is the original channel part 3 of the door glass run 31
Although the cross-sectional shape of 2 does not basically change, the flange lip 34 on the vehicle interior side of the pair of flange lips 33 and 34 that fits into the flange portion of the door sash portion is This is based on the fact that the length W gradually increases toward the bottom according to the shape.

When such a door glass run 31 is formed of a thermoplastic elastomer, the channel portion 32, which has a common shape in any cross section as shown in FIG. The door glass run 31 having the required cross-sectional shape is formed by molding both flange lips 33 and 34 while forming the channel portion 32 previously extruded as a secondary molding in a predetermined mold. I'm trying to get

More specifically, when extruding the channel portion 32, waste portions 35 and 36 that are unnecessary as a final product shape are formed in a part of the channel portion 32,
Immediately before molding the flange lips 33, 34, the waste portions 35, 36 are cut to expose a cut surface 37, and the cut surface 37 is used as a joint surface to form the flange lip 3.
By molding the molds 3 and 34, the door glass run 31 having the required shape in which the channel portion 32 and the flange lips 33 and 34 are integrated with each other is first obtained.

The sliding surfaces for facilitating sliding with the door glass are provided on the outer surface sides of the pair of seal lips 38 and 39 protruding inside the channel portion 32 and on the inner bottom of the channel portion 32. The conductive resin layer 40 is co-extruded.

The reason why the waste portions 35, 36 are cut immediately before the flange lips 33, 34 are molded is that if the cut surface 37 to be the joining surface is exposed from an early stage, the cut surface is cut. This is because the bleed-out phenomenon of the components contained in the material occurs on the material 37, or dust or moisture adheres to the material 37, and the adhesive bonding strength between the material and the flange lips 33 and 34 decreases.

[0007]

In the above-described conventional technology for manufacturing a door glass run made of a thermoplastic elastomer,
It is necessary to cut the waste portions 35 and 36 prior to molding, so that the cost increases due to the increase in the number of processes, and especially in the case of a door glass run made of a resin such as a thermoplastic elastomer. Since the adhesive bonding strength at the bonding surface is lower than that of rubber, it is necessary to pay close attention to the management of molding conditions and the like, which makes the process management complicated, which is not preferable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and particularly relates to a weather strip made of a thermoplastic elastomer having an extruded portion and a die formed portion as represented by the above-mentioned door glass run. A weather strip and a method of manufacturing the same that eliminate the need for a cutting process after extrusion molding and before molding, and at the same time dramatically improve the bonding strength at the junction between the extrusion molding and the molding. It is what we are going to offer.

[0009]

According to a first aspect of the present invention, there is provided an extruded portion formed of a thermoplastic elastomer and formed by an extrusion method, and a part of the extruded portion formed by a mold forming method. A weather strip for an automobile, comprising a mold forming part integrally formed with the molding part, wherein a part of the extrusion forming part which is to be a joining surface with the mold forming part is formed when forming the extrusion forming part itself. The extrusion layer is simultaneously extruded and the extruded section and the mold section are adhesively bonded to each other with this bonding layer.

The above-mentioned automotive weather strip is a general term for a concept including various types of automotive sealing members such as a door glass run and the like, that is, a sealing member used for an opening / closing portion of a window frame or a door of an automobile. It is not limited to door glass runs only.

The thermoplastic elastomer (TPE), which is a material of the extruded part and the molded part, is one of soft synthetic resins and is a polymer substance having rubber-like elasticity at room temperature. In this state, the crosslinked rubber is dispersed. As a typical example, an olefin type (referred to as TPO) or a styrene type is used. Of these, the extruded part material must be capable of conforming to the shape of a door, a vehicle body or a door glass, and satisfying the sealing property between them, and in many cases, the surface hardness after molding is (JIS). A) 80 ° or less is used.

On the other hand, it is absolutely necessary that the bonding layer has an excellent affinity for the extruded portion and the die-molded portion, and therefore has excellent bonding strength, and that it can be co-extruded with the extruded portion itself. When the extruded section and the mold forming section are made of an olefin-based or styrene-based thermoplastic elastomer as described above, the bonding layer includes the extruded section and the mold. A thermoplastic elastomer or vinyl acetate resin (EVA) of the same type as the material of the molding part, which has a high resin content,
That is, those having a surface hardness after molding higher than those of the extruded part and the mold part, for example, those having a hardness (JIS A) of 90 ° or more are used.

According to a second aspect of the present invention, there is provided a weather strip forming technique according to the first aspect of the present invention, in view of a manufacturing method. A joint layer is simultaneously extruded at the time of molding the extruded portion itself on a portion to be a joining surface with, and molding of the mold molding portion is performed while facing this joint layer in a predetermined mold. The present invention is characterized in that the extruded part and the mold part are bonded to each other with a bonding layer.

Therefore, according to the first and second aspects of the present invention, the joint layer is exposed on a part of the outer surface of the extruded portion by simultaneously extruding the joint layer when the extruded portion is formed. Both are molded integrally in the form. At this stage, as if the bonding layer substantially functions as a part of the extruded portion, a skin layer containing a large amount of resin is formed on the surface layer.

Subsequently, the extrusion-molded portion with the bonding layer is set in a predetermined mold, and the mold-forming portion is formed in a predetermined shape with the bonding layer facing a space (cavity) in a product shape portion in the mold. , Ie, by a known injection molding method. Although the bonding layer is in a solidified state until then, it is plasticized again due to its thermal influence by injecting a plasticizing material to be a mold molding. At this time, even if the components of the extruded part material bleed out or dust or moisture adhered to the surface of the joining layer, the skin layer containing a large amount of resin is plasticized and fluidized, and the adhesion inhibiting component is contained in the fluidized resin. It is presumed to be unevenly dispersed. As a result, it serves to fuse and integrate the extruded part and the mold part with each other due to the affinity characteristics of the materials.

[0016]

According to the first and second aspects of the present invention, at the time of forming the extruded portion, the joint layer which functions as an adhesive joint portion at the time of molding is simultaneously extruded. It is not necessary to cut a part of the extruded part prior to mold forming as in the past, and it is possible to significantly reduce costs by reducing the number of steps. The interposition of the bonding layer between them has the effect of further increasing the bonding strength between the two.

[0017]

1 to 3 show the structure of a door glass run as a preferred embodiment of the present invention.
A front door 1 shown in FIG. 1 (this figure shows a view of the front door as viewed from the vehicle interior side) 1 is along a center pillar, that is, when the door is applied to a glass run vertical side 3 of a glass run 2. An example is shown. It is well known that the glass run vertical side portion 3 is connected to the glass run upper side portion 5 which is a general portion via a corner-shaped forming portion 4.

As shown in FIGS. 1 and 2, the glass run vertical side portion 3 includes a channel portion 6 having a substantially U-shaped cross section.
A pair of flange lips 7, 8 which are bent so as to be folded outward from the left and right opening edges of the channel portion 6.
And the channel portion 6 is formed to have a uniform cross-sectional shape over its entire length in the longitudinal direction, whereas only the flange lips 7, 8 or one of them, that is, only the flange lip 8 on the vehicle interior side, is formed. FIG.
Similarly, the flange length W is formed so as to gradually change in the longitudinal direction. Note that a pair of seal lips 9,
10 are formed to project obliquely. A slidable resin layer for facilitating sliding with the door glass is simultaneously extruded on the outer surface side of both seal lips 9 and 10 and the inner bottom of channel portion 6 as in FIG. In some cases, a surface treatment agent for imparting slidability may be applied.

Then, after the channel portion 6 is extruded singly as a uniform cross-sectional shape by the extrusion molding method,
The channel portion 6 is subjected to secondary molding, and both flange lips 7, 8 are formed by an injection molding method as a mold forming method, so that the flange lips 7, 8 are integrated with the channel portion 6 for the first time. Thus, here, the channel portion 6 functions as an extrusion molding portion, while the two flange lips 7, 8 function as a mold molding portion.

In this embodiment, as shown in FIG. 3, when the channel portion 6 is extruded, a bonding layer is formed on a portion of the channel portion 6 which is to be a bonding surface with both flange lips 7 and 8. 11 and 12 are co-extruded in advance, and the flange lips 7 and 8 are integrally bonded together with the bonding layers 11 and 12 at the time of die molding (injection molding) as secondary molding following the extrusion. I have.

The thermoplastic elastomer (TPE) which is a material of the channel portion 6 as an extruded portion and the flange lips 7 and 8 as a molded portion is a polyolefin (TPO) or polystyrene type. Is preferably used, and the surface hardness after molding is preferably (JI
SA) Those having an angle of 80 ° or less are used. For example, as a material of the channel portion 6 as an extruded portion, “Santoprene 121-73W175” manufactured by AES which is a polyolefin-based thermoplastic elastomer (TPO) is used. The material No. 8 is a polyolefin-based thermoplastic elastomer (TPO) manufactured by AES “Santoprene 12”.
1-79W233 "is used.

On the other hand, the material of the bonding layers 11 and 12 is that it has excellent affinity for the channel portion 6 and the flange lips 7 and 8 and therefore has excellent bonding strength, and that it can be co-extruded with the channel portion 6. When a polyolefin-based or polystyrene-based thermoplastic elastomer is used as a material for the channel portion 6 and the flange lips 7, 8, the channel portion 6 and the flange lip are used as materials for the bonding layers 11, 12. The same kind of thermoplastic elastomer or vinyl acetate resin (EVA) as that of the materials 7 and 8 is used.
As a material higher than 8, a material having a hardness (JISA) of 90 ° or more is used. For example, as a material of the bonding layers 11 and 12, a polyolefin-based thermoplastic elastomer (T
PO), “Santoprene 123-
50 "is used.

That is, in the present embodiment, as shown in FIG. 3A, the thickness dimension of the portion to be joined to the flange lips 7 and 8 is 50 to 1 by a known extrusion molding method.
The channel portion 6 having the bonding layers 11 and 12 of about 00 μm is extruded into a uniform cross-sectional shape, cut into a predetermined length, set in an injection mold for flange lip molding, and clamped. I do. At that time, the channel section 6
The above-mentioned joining layers 11 and 12 are arranged so as to face the cavities (product shape space) of the injection mold to become the flange lips 7 and 8, and a predetermined resin material plasticized in that state is disposed. The flange lips 7 and 8 are injection-molded as secondary molding by injection. Thereby, the bonding layers 11,
The channel portion 6 and the flange lips 7, 8 are bonded and bonded to each other via 12.

At this time, the bonding layers 11 and 12 which are formed integrally with the channel portion 6 in advance as a part thereof are thermally affected by the material to be the flange lips 7 and 8 being injected. Is plasticized again, and if the bonding layer 11,
Even if the component of the material of the channel portion 6 bleeds out or dust or moisture adheres to the surface of the channel 12, the skin layer containing a large amount of resin is plasticized and fluidized, and Since the bonding layers 11 and 12 are non-uniformly dispersed in the inside, the bonding layers 11 and 12 serve to firmly fuse and join the channel portion 6 and the flange lips 7 and 8 due to the affinity effect.

Here, even if it takes a predetermined time from the extrusion of the channel portion 6 to the joint formation of the channel portion 6 and the flange lips 7, 8, the bonding layers 11, 12 remain intact. The bonding function of the channel portion 6 and the flange lips 7, 8 is firmly bonded with the bonding layers 11, 12 without lowering the bonding function.

The present inventors prepared dumbbell-shaped test pieces (No. 3 test pieces) S1, S2 and S3 as shown in FIG. 4 in accordance with JIS K6251 and conducted a tensile test.
The breaking strength was measured. Test piece S shown in FIG.
Reference numeral 1 is obtained by punching and forming a half-split test piece Sa from an extruded resin plate, injection-molding the remaining half-split test piece Sb using it as an insert, and forming and bonding the two with a bonding surface P. . Test piece S shown in FIG.
2. First, a half-split test piece Sa is stamped and formed from an extruded resin plate, and a surface to be a joining surface P is cut and exposed, and the remaining half-split test piece Sb is injection-molded as an insert. Thus, the two are formed and bonded together with the bonding surface P. Further, a test piece S3 shown in FIG. 3 (C) is obtained by first forming a half-split test piece Sa from a resin plate obtained by simultaneously extruding a joining layer Sc together with a resin plate, and then using the same as an insert to form the remaining half-split test. Piece Sb
Are injection-molded, and both are formed and bonded together with a bonding layer Sc. Note that the test piece S2 in (B) corresponds to that of the conventional technique, and the test piece S2 in (C)
Reference numeral 3 corresponds to the above embodiment.

The results of the tensile test show that the test piece S1 in FIG. 5A has a breaking strength of 2.5 MPa and the test piece S1 in FIG.
2 has a breaking strength of 2.9 MPa, and the test piece S3 shown in FIG.
Has a breaking strength of 3.9 MPa, indicating that the breaking strength of the above-described embodiment is the most excellent.

The half-split test piece Sa was left indoors at room temperature for 2 weeks, and the remaining half-split test piece Sb was injection-molded using the insert as an insert. As a result of conducting a tensile test,
Its breaking strength was 3.4 MPa. This is equivalent to that of the prior art.
It is superior to 9 MPa, and it can be understood from the above that the one in the above-described embodiment is more effective for the bleed-out phenomenon due to the change with time.

[Brief description of the drawings]

FIG. 1 is an inside perspective view of an automobile door showing a mounted state of a door glass run.

FIG. 2 is a cross-sectional view of the door glass run shown in FIG.

FIG. 3 is an explanatory sectional view showing a manufacturing procedure of the door glass run shown in FIG. 2;

FIG. 4 is an explanatory view of a dumbbell-shaped test piece for evaluating the breaking strength of the door glass run.

FIG. 5 is an explanatory view showing an example of a conventional door glass run.

FIG. 6 is a sectional view taken along line DD of FIG. 5;

FIG. 7 is a sectional view of a general part of the door glass run shown in FIG. 6;

[Explanation of symbols]

 2: Door glass run (weather strip for automobiles) 3: Glass run vertical side portion 6: Channel portion (extrusion molding portion) 7, 8: Flange lip (mold molding portion) 9, 10: Seal lip 11, 12: Joining layer

Claims (2)

[Claims] 1. An extruded part formed of a thermoplastic elastomer and formed by an extrusion method, and a mold part integrally joined to a part of the extruded part by a mold forming method. A weather strip for an automobile, comprising: simultaneously extruding a joining layer on a portion of the extruded portion to be a joining surface with a mold forming portion when the extruded portion itself is formed; A weather strip for automobiles, characterized in that an extruded part and a mold part are adhesively bonded to each other with the above. 2. An extruded portion formed of a thermoplastic elastomer and formed by an extrusion method, and a mold formed portion integrally joined to a part of the extruded portion by a mold forming method. A method for manufacturing a weather strip for an automobile, comprising: simultaneously extruding a joining layer on a portion of the extruded portion to be a joining surface with a mold forming portion when forming the extruded portion itself. An automobile characterized in that a molding part is formed while a joining layer faces a predetermined mold, and the extruded part and the molding part are bonded and bonded to each other with the joining layer. Of manufacturing weatherstrips for automobiles.