JP3424960B2 - Method for integrally molding an extruded product having a shape changing portion - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for integrally molding an extruded product having a shape-changing portion used for, for example, wind molding of an automobile. 2. Description of the Related Art Conventionally, a window molding made of an extruded synthetic resin has been used to attach a window glass to a vehicle body and to cover a gap between the two. By the way, as shown in FIG. 6, the wind molding M of the automobile C has a groove-shaped garter drainage at the window side W1 so that water droplets generated by the wiper do not scatter on the window glass on both sides of the vehicle body. The upper part W2 has no gutter so that the water in the window is easily discharged to the outside. [0003] Various methods have been proposed for obtaining an extruded product having a shape-changing portion whose shape partially changes in this way. For example, there is a method in which extruded products having the same cross-sectional shape are continuously manufactured, partially cut out in a later process, and processed into a predetermined product shape. Further, a method is provided in which a movable shutter is provided in front of a die of an extrusion molding machine, and the die is partially opened or closed by the movable shutter to obtain an extruded product whose shape changes (Japanese Patent Laid-Open No. 3-143730). 7 and FIG. 8, the center of the cross section of the extruded product 60 is partially hollowed, and the hollow portion 61 is partially crushed by a pressure roll or the like to form an outer portion of the extruded product 60. There is known a method of changing the shape and eliminating the garter portion 62 (Japanese Patent Laid-Open No. 2-124315). [0005] However, the excision processing shown first is
Not only is the process complicated and the efficiency is not good, but the quality of the finished surface is poor, and there is a problem in quality such as dimensional variations. On the other hand, in the second method, although the appearance of the product is good and no post-processing is required, there is a dislike that the mold structure becomes complicated and its control becomes difficult. Further, in the third method, since the hollow portion 61 is provided in the product, the product does not have rigidity and may not meet the required strength. Furthermore, not only other equipment such as a pressure roll for crushing the hollow portion is necessary,
In some cases, traces of pressure bonding with the roll remained on the surface of the product. SUMMARY OF THE INVENTION The present invention has been proposed in view of the above situation, and has been developed to provide an extruded product having a shape-changed portion having a good product appearance and sufficient strength. It is an object of the present invention to provide a method for economically and efficiently obtaining a simple equipment structure. [0008] That is, the present invention provides:
When continuously and integrally molding a molded product having a shape-changed part in an extruder, the extruder includes:
A main body die outlet for forming a main body of the extruded product and a main body resin flow path, and a die having an inner die outlet and an inner resin flow path formed inside the main body die outlet; And a constant amount of the main body resin material is always supplied from the first extruder through the main body resin flow path, and the inner resin material is supplied from the second extruder to the inner die outlet at the shape changing portion. Supply or stop the supply through the inner resin flow path in total or reduced amount depending on the form, at the time of reduced supply or stop supply of the inner resin material, the amount of the body resin material extruded from the body die outlet A vacuum or reduced pressure space portion is created inside, whereby the main body resin material extruded from the main body die outlet is deformed to form a shape change portion. According to integral molding method of extrusion with Jo change section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing an example of an extruded product having a shape-changed portion obtained by the method of the present invention, and FIG. 2 is an enlarged sectional view showing an extruded product of a portion where the shape-changed portion is completely formed. 3 is an enlarged cross-sectional view showing an extruded product at a portion where no shape change portion is formed, FIG. 4 is a front view showing a die outlet of an extruder for carrying out the method of the present invention, and FIG. 5 shows an outline of the extruder. It is sectional drawing. As shown in FIG. 1, an extruded product 10 obtained by the method of the present invention comprises a main body 11 and a shape changing portion 12 formed integrally with a part of the main body 11. The shape of the shape changing portion 12 is configured to change continuously on the product. That is, in the extruded product 10, the extruded product 10 </ b> A in a state where the shape change portion 12 is completely formed in the main body portion 11, and the shape change portion 12 adheres integrally to the upper edge of the main body portion 11, An extruded product 10B in a state where the shape change portion 12 has disappeared is continuously formed. As shown in FIGS. 2 and 3, the shape-changing portion 12 forms a groove-shaped garter portion 15 with the upper edge of the main body 11 to prevent rainwater from discharging and scattering. Therefore, it is used as a wind molding for automobiles that is functional and effective in appearance. In particular, the extruded product 10A in which the shape changing portion 12 is formed is provided on the side of the window of the automobile to prevent water droplets from scattering on the window glass and to be discharged to the outside. The extruded product 10B in close contact with is preferably used in the upper part of the window because water droplets easily flow backward. Code 16
Denotes a glass holding portion provided on the main body 11, reference numeral 17 denotes an engagement portion with the vehicle body, and reference G denotes a window glass. The extruded product 10 has an inner resin material P2 in a main resin material P1 constituting a main body portion 11 and a shape changing portion 12. The inner resin material P <b> 2 is provided between the main body portion 11 and the shape changing portion 12, and is defined by a thin wall portion 13 and a bent portion 18. The inner resin material P2 is configured such that the supply amount of the resin is changed by controlling the extruder, and the volume thereof is continuously increased and decreased. When this inner resin material P2 is extruded in its entirety, it forms a part of the main body 11 as shown in FIG. Form 10A. As shown in FIG. 3, when the inner resin material P2 is not reduced or extruded, a part of the main body 11 occupied by the inner resin material P2 is created as a space. Since this space portion is decompressed or evacuated in the main body resin material P1, the thin wall portion 13 is bent inward, and the shape change portion 12 comes into close contact with the upper edge of the main body portion 11, thereby forming the extruded product 10B. I do. The volume of the inner resin material P2 is gradually changed between the extruded product 10A and the extruded product 10B,
The rising form of the shape changing portion 12 from the main body 11 is continuously and gradually changed. The resins used for the main resin material P1 and the inner resin material P2 include known thermoplastic resins such as olefin elastomers such as polypropylene and polyethylene, vinyl halides such as vinyl chloride, and ionomer elastomers. It is preferably used. Also, depending on the required physical properties of the extruded product 10, the main resin material P1 and the inner resin material P1 may be used.
It is also possible to constitute 2 from different materials. In addition, a soft resin layer may be provided on the glass holding portion 16 and the engaging portion 17 in order to prevent the window glass G and the vehicle body from being damaged and to enhance the adhesion. Next, the method of the present invention will be described. FIGS. 4 and 5 schematically show an extruder for carrying out the method of the present invention. Reference numeral 20 denotes an extruder, 21 denotes a die, and 22 denotes an extruder. As shown in the figure, the die 21 is provided with a main body die outlet 23 that defines the shape of the extruded product in a state where the shape change portion 12 is completely formed. Connected.
The main body resin flow path 24 is provided with a first extruder 22A for supplying the main body resin material P1. This first extruder 22
A always supplies a constant amount of the main body resin material P1. On the other hand, inside the die 21, an inner resin flow path 25 is formed inside the main body resin flow path 24. The inner resin flow path 25 includes a second extruder 22B that supplies the inner resin material P2, and opens inside the main body die outlet 23. Numeral 26 is the inner die outlet. At this time, the inner die outlet 26 has an appropriate clearance around the inner die outlet 26 so that the thin wall portion 13 and the bent portion 18 are provided in the extruded product 10 by the main body resin material P1 from the main body die outlet 23. It is arranged with. The second extruder 22B supplies or stops supplying the entire amount or the reduced amount according to the form of the shape changing unit 12. First, a predetermined amount of the main resin material P1 is supplied from the first extruder 22A, and the second extruder 2A
From 2B, the entire amount of the inner resin material P2 is supplied. The supplied main body resin material P1 and inner resin material P2 flow through the resin flow paths 24 and 25 in the die 21, respectively, and reach the die outlet. From the main body die exit 23, the die exit 2
Since the entire amount of the inner resin material P2 is extruded from the inner die outlet 26 from the main resin material P1 formed into the three shapes, an extruded product in which the shape change portion 12 as shown in FIG. 10A is obtained. Next, by controlling the second extruder 22B to reduce the supply amount of the inner resin material P2, the inner resin material from the inner die outlet 26 previously occupied by the entire amount of the inner resin material P2. The volume of P2 is reduced, and a space in a vacuum or reduced pressure state is formed in the main body resin material P1. At this time, the thin wall portion 1 that partitions the space portion
3 is depressed inward, and the main body resin material P1 falls down via the bent portion 18. Thereby, an extruded product in which the shape change portion 12 does not completely project from the main body portion 11 is obtained. Subsequently, when the supply of the inner resin material P2 from the second extruder 22B is reduced and further stopped, the predetermined volume in the main resin material P1 occupied by the inner resin material P2 disappears, and The wall portion 13 is deformed until the inner walls of the first and second contact portions are in close contact with each other. Then, an extruded product 10B in which the shape changing portion 12 overlaps the upper edge of the main body portion 11 as shown in FIG. 3 can be obtained. Further, when the supply of the inner resin material P2 from the second extruder 22B is resumed, on the contrary, the volume of the inner resin material P2 in the main resin material P1 increases and the outer shape of the product is formed. The main body resin material P1 to be deformed from inside. Thereby, the wall portion 13 is extended, and the shape changing portion 12 is formed by being gradually pushed up from the main body portion 11. As shown and described above, according to the method for integrally forming an extruded product having a shape-changing portion according to the present invention, not only is a post-process unnecessary and efficient, but also a mold is provided. Since it does not move, the mold structure is simple and extremely economical. Furthermore, the obtained product does not have a hollow portion or the like, so that it has sufficient strength, and has no appearance of pressing by a pressure roll or the like, so that the appearance is good.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an example of an extruded product having a shape changing portion obtained by a method of the present invention. FIG. 2 is an enlarged sectional view showing an extruded product at a portion where a shape change portion is completely formed. FIG. 3 is an enlarged cross-sectional view showing an extruded product at a portion where no shape change portion is formed. FIG. 4 is a front view of a die outlet of an extruder for carrying out the method of the present invention. FIG. 5 is a sectional view schematically showing an extruder. FIG. 6 is a perspective view showing a front portion of the automobile. FIG. 7 is a cross-sectional view showing an example of an extruded product having a conventional shape changing portion. FIG. 8 is a cross-sectional view showing a state in which a shape change portion is not formed in FIG. [Description of Signs] 10 Extrusion molded product 11 Main body 12 Shape change section 13 Wall P1 Body resin material P2 Inside resin material 20 Extruder 21 Die 22 Extruder 23 Body die outlet 24 Body resin flow path 25 Inner resin flow path 26 Inside die exit P1 Body resin material P2 Inside resin material

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 47/00-47/92

Claims (1)

(57) [Claim 1] When an extruder is used to continuously and integrally mold a molded article having a shape-changed portion, the extruder is provided with a main body of the extruded article. A die having a main body die outlet and a main body resin flow path for molding a die, and a die having an inner die outlet and an inner resin flow path formed inside the main body die outlet are attached. A constant amount of the main body resin material is always supplied from the extruder through the main body resin flow path, and the inner resin material is entirely or reduced from the second extruder to the inner die outlet according to the shape of the shape changing portion. And supply or stop supply through the inner resin flow path, at the time of reduced supply or supply stop of the inner resin material,
A vacuum or reduced pressure space is created inside the main body resin material extruded from the main body die outlet, so that the main body resin material extruded from the main body die outlet is deformed to form a shape change portion. An integrated molding method for an extruded product having a shape-changing portion.