JP2001105470A - Method for manufacturing curved member and weatherstrip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a curved member wherein the curved member having a curved part of a very large curvature can be manufactured only by extrusion molding without using a mold, and a weather strip which is excellent in strength of the curved part, light in weight and low in manufacturing cost. SOLUTION: In a method for manufacturing a curved member by using a head having a die and a pin wherein mutual positional relation can be changed in extrusion molding of a thermoplastic elastomer composition or a thermoplastic resin composition, a manufacturing method for the curved member wherein a positional relation of the die and the pin, and an extruded amount are controlled by being linked with, and a weatherstrip which is manufactured by the manufacturing method for the curved member, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bent member and a weather strip manufactured by the method.

[0002]

2. Description of the Related Art Automotive weather strips include doors,
It is installed on the roof side, etc., and aims to prevent wind and rain and sound from entering the room. Conventionally, rubber and soft polyvinyl chloride have been used for weather strips for automobiles.
Extruded products of the thermoplastic elastomer composition have been used (JP-A-9-176408). In this case, even if the weather strip obtained by extrusion molding is used as it is to mount it on a door or the like, it has been difficult to bring the weather strip into close contact with the shape of the corner portion of the door or the like. Therefore, under the present circumstances, after extrusion, it is used after being shaped with a mold and the like to conform to the shape of a corner portion of a door or the like, and the number of working steps is increased accordingly. In addition, conventional weatherstrips have low strength at the bends,
There has been a demand for a weatherstrip having excellent strength in a bent portion.

On the other hand, JP-A-59-123636 and JP-A-8-34069 propose a method and an apparatus for manufacturing a bent pipe, which include a radiator hose, a heater hose, a duct hose and the like. Accordingly, it has not been possible to manufacture a bent member having a bent portion with a very large curvature, such as a weather strip for an automobile, by these methods.

Japanese Patent Application Laid-Open No. 5-104606 discloses a method for manufacturing a specially shaped weather strip whose width changes in the length direction, even if the extrusion opening area is changed by a movable member. Is disclosed, but the method is unsuitable for producing a weatherstrip having a substantially constant width in the length direction and having corners and / or sharp corners. there were.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a bent member having a bent portion having an extremely large curvature by only extrusion molding, and a method for manufacturing a bent member having excellent strength at the bent portion and light weight. An object of the present invention is to provide a weather strip which is inexpensive to manufacture.

[0006]

SUMMARY OF THE INVENTION The present inventor has developed a bending member having a bent portion having an extremely large curvature, particularly a weather strip having a width which is substantially constant in a longitudinal direction and which has a corner portion and / or an acute angle portion. To manufacture, the extrusion shape is changed by widening and narrowing the interval between the die and the pin in the direction perpendicular to the axial direction, and the extrusion amount is also positively changed if necessary, and constant extrusion is used if unnecessary. The inventors have found that it is effective to control the amount to be maintained, and have completed the present invention.

That is, the present invention relates to an extrusion molding of a thermoplastic elastomer composition or a thermoplastic resin composition.
A method for manufacturing a bent member using a head having a die and a pin capable of changing a mutual positional relationship, wherein the positional relationship between a die and a pin and an extrusion amount are controlled in conjunction with each other. Provided is a method for manufacturing a bent member.

Further, the present invention relates to an extrusion molding of a thermoplastic elastomer composition or a thermoplastic resin composition,
At least one corner and / or using a head having a die and a pin capable of changing the positional relationship with respect to each other;
Or, a method of manufacturing a weather strip having an acute angle portion, wherein the method controls the extrusion shape and the extrusion amount by interlocking the positional relationship between the die and the pin and the extrusion amount. I do.

It is preferable that the thermoplastic elastomer composition or the thermoplastic resin composition is a foam.

It is preferable that the thermoplastic elastomer composition is a thermoplastic elastomer composition in which the continuous phase is a thermoplastic resin composition and the dispersed phase is at least partially a dynamically crosslinked elastomer composition. .

Further, the present invention provides a weather strip manufactured by the method for manufacturing a bent member.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. According to a first aspect of the present invention, there is provided a method for manufacturing a bent member using a head having a die and a pin capable of changing a positional relationship with each other in extrusion molding of a thermoplastic elastomer composition or a thermoplastic resin composition. A method for manufacturing a bent member, wherein the positional relationship between the die and the pin and the extrusion amount are controlled in conjunction with each other.

In the method for manufacturing a bent member according to the present invention, a head having a substantially cylindrical die and a pin inserted into the die is used for extrusion molding. The die and pin
A tubular mouth for extruding the tubular body is formed. In the head, the die and the pin are provided so that the positional relationship between them can be changed. One of the die and the pin may be fixed and the other may be movable, or both the die and the pin may be movable. The die and the pin change their positional relationship with each other by moving one or both mainly in a direction perpendicular to the extrusion direction. The means for changing the positional relationship between the die and the pin is not particularly limited, and a known device such as an actuator can be used.

In the method for manufacturing a bent member according to the present invention, the thermoplastic elastomer composition or the thermoplastic resin composition is extruded from the head by an extruder or the like, and is extruded. In the present invention, during extrusion molding,
When the shape of the tubular mouth is changed by changing the positional relationship between the die and the pin, a bent member is obtained. Specifically, the positional relationship between the die and the pin is adjusted in advance so that the extrudate is extruded linearly from the head along the extrusion direction, and the positional relationship between the die and the pin is changed from that state to change the tubular port. When the shape of the die is changed and extruded, the flow rate at the wider gap between the inner wall of the die and the pin increases, so the wall thickness at the wider gap increases, and as a result, the tube extruded from the head The body bends in a direction that is located outward when the thickness increases.

Here, a feature of the present invention resides in that in the above-mentioned extrusion molding, the positional relationship between the die and the pin and the extrusion amount are controlled in conjunction with each other. That is, in the present invention, the amount of extrusion is increased or decreased in accordance with the timing of forming the linear portion or the bent portion. The means for controlling the positional relationship between the die and the pin in conjunction with the extrusion amount is not particularly limited, but a program for linking the operation of the device for operating the positional relationship between the die and the pin with the operation of the device for performing the extrusion is provided. An incorporated control panel or the like can be used.

A specific example of controlling the positional relationship between the die and the pin and the extrusion amount in conjunction with each other will be described below. (1) When forming a straight portion, the positional relationship between the die and the pin is set so that the extrudate is pushed straight out of the head along the extrusion direction, and the state is not changed. The amount should be kept constant. (2) In the case where the curvature of the bent portion is formed to be constant, the positional relationship between the die and the pin is changed from the positional relationship of (1) to maintain a constant state, and to form a straight line portion. It is only necessary to keep a constant extrusion rate smaller than in the case. In this case, it is preferable to increase or decrease the amount of extrusion in accordance with the amount of change in the positional relationship between the die and the pin. That is, when the amount of change in the positional relationship from the above (1) is large, it is preferable to greatly reduce the extrusion amount, and when it is small, it is preferable to slightly reduce the extrusion amount. (3) In the case where the curvature of the bent portion is changed, the amount of change in the positional relationship may be increased or decreased, and the extrusion amount may be increased or decreased at the same time. For example, when the amount of change in the positional relationship is increased, the amount of extrusion is reduced accordingly, and when the amount of change in the positional relationship is reduced, the amount of extrusion is increased accordingly.

By combining the method of controlling the positional relationship between the die and the pin and the extrusion amount in conjunction with each other, it is possible to easily form a bent member having a bent portion having a large curvature. Also, by changing the speed at which the positional relationship between the die and the pin is changed, the time for maintaining the position at the changed position, and the like, bent members having various shapes can be obtained.

Hereinafter, the method for manufacturing a bent member of the present invention will be described in more detail with reference to the accompanying drawings. Note that the present invention is not limited to those described in the accompanying drawings. FIG.
1 is a sectional view of a head used in the present invention. The head 1 has a die 2 and pins 3. Inner wall of die 2 and pin 3
A thermoplastic elastomer composition or a thermoplastic resin composition 4 (hereinafter, referred to as “composition 4”) is extruded from the tubular opening formed by the above. In FIG. 1, the pin 3 is movable, and when the pin 3 moves to change the positional relationship with the die 2, the composition 4 extruded from the head 1.
Changes. In FIG. 1, the distance between the position of the pin 3 and the lower side of the inner wall of the die 2 is wider than the distance between the upper side and the extrusion amount from the lower side. After being extruded from 1, it bends in a direction in which the lower side is located outside.

FIG. 2 shows an example of a head shape suitably used in the present invention. The die 2 has a taper 6 on the inner surface, and has a cylindrical portion on the composition supply side (left side in the figure) and the tip side (right side in the figure) from the taper 6. The pin 3 has a taper 5, and has a cylindrical portion on the composition supply side (left side in the figure) and the tip side (right side in the figure) from the taper 5. According to the present head shape, the thermoplastic elastomer composition or the thermoplastic resin composition is rectified by the parallel portion formed by the cylindrical portion of the die 2 and the cylindrical portion of the pin 3 on the tip side, and the desired dimensional stability is obtained. Is improved. As shown in FIG. 2, when the pin 3 is located at the center of the head 1,
The inner wall of the die 2 and the pin 3 form a tubular opening having a width of 1.5 mm. The pin 3 can move up and down (or left and right), preferably in any radial direction, up to 1 mm from the center of the head 1.

FIG. 3 is a conceptual view showing an example of a bending member manufacturing apparatus for implementing the bending member manufacturing method of the present invention. The bending member manufacturing apparatus 7 includes a head 1, an extruder 8 that supplies the composition 4 to the head 1, and an actuator that is connected to the head 1 and determines the positional relationship between the die 2 and the pin 3 by operating the position of the pin 3. And a control panel 1 for controlling the actuator 9 and the rotation speed of the extruder 8 in conjunction with each other.
0 is provided. The control panel 10 incorporates a program for linking the actuator 9 for operating the pin 3 and the rotation speed of the extruder 8. The position of the pin 3 is adjusted to the center in advance so that the composition 4 extruded from the head 1 is extruded linearly from the head 1 along the extrusion direction. When a straight portion is manufactured by the bending member manufacturing apparatus 7, the position of the pin 3 is fixed to the center as it is,
What is necessary is just to keep the rotation speed of the extruder 8 constant.

When the bent portion is manufactured, the pin 3 is moved by the actuator 9 to reduce the rotation speed of the extruder 8. In this case, the displacement of the pin 3 and the rotation speed of the extruder 8 are controlled by the control panel 10 in an interlocked manner. Therefore,
The composition 4 having a desired shape can be easily obtained. Specifically, when increasing the curvature, the displacement amount of the pin 3 is increased, and the decrease in the rotation speed of the extruder is increased.
Control is performed in conjunction with the control panel 10. When a bending member having a small curvature is used, the displacement is controlled by the control panel 10 so that the displacement of the pin 3 is reduced and the rotation speed of the extruder is reduced. For example, when the angle is an acute angle, the extrusion amount is reduced to 50% or less, when the angle is a right angle, the extrusion amount is reduced to 50 to 70%, and when the angle is an obtuse angle, the amount is 70 to 90%.
%.

FIG. 4 shows a manufacturing apparatus 7 for a bent member.
It is a figure which shows an example in the case of manufacturing a weatherstrip abcdea with (A) the shape of a weatherstrip, (B) the position (movement amount) of the pin 3, and (C) the rotation speed of the extruder 8. FIG. Here, the weather strip shown in FIG. 4A has a substantially constant width in the length direction.
Moreover, it is a weatherstrip having corners and / or sharp corners. The weatherstrip is substantially constant in width and has at least one portion (corner, acute) that changes direction at a right angle or less. On the other hand, it also has an obtuse angle part and a straight part.

In the straight section from the point a to the vicinity of the point b, the position of the pin 3 and the rotation speed of the extruder 8 are constant. The pin 3 is located at the center of the head 1 (movement amount 0 mm), and the rotation speed of the extruder 8 is 40 rpm. The same applies to the straight line portion from the vicinity of the point b to the vicinity of the point c, the straight line portion from the vicinity of the point c to the vicinity of the point d, the straight line portion from the vicinity of the point d to the vicinity of the point e, and the straight line portion from the vicinity of the point e to the point a. . Since the vicinity of the point b is a curved portion having a large curvature, the pin 3 is largely moved by the control panel 10 so that the rotation speed of the extruder 8 is reduced synchronously. The movement amount of the pin 3 is 1.0 mm at the maximum, and the rotation speed of the extruder is 10 rpm at the minimum. Since the vicinity of the point c is a curved portion having a small curvature, the pin 3 is moved small by the control panel 10 so that the rotation speed of the extruder 8 is reduced synchronously. The maximum travel of pin 3 is 0.3
mm, and the rotation speed of the extruder is at least 30 rpm. Since the vicinity of the point d and the vicinity of the point e are curved portions having an intermediate curvature between the vicinity of the point b and the vicinity of the point c, the position of the pin 3 and the rotation speed of the extruder 8 are intermediate therebetween. Pin 3
Is 0.6 mm at the maximum, and the rotation speed of the extruder is 20 rpm at the minimum.

Japanese Patent Application Laid-Open No. 59-123636 has a die and a core for extruding a tubular body, and the die or the core is formed so as to be movable in a direction transverse to the extrusion direction. 2. Description of the Related Art An apparatus for manufacturing a bent tube including a moving means for moving a die or a core has been proposed. Also, JP-A-8-3
Japanese Patent No. 4069 proposes an improved product thereof. However, in practice, it has not been possible to manufacture a bent member having a bent portion with a large curvature. On the other hand, according to the present invention, not only the positional relationship between the die and the pin but also the extrusion amount is changed, and these are controlled in conjunction with each other. The extruding amount can be reduced in conjunction with, and the speed of changing the positional relationship between the die and the pin can be made sufficiently large with respect to the extruding speed, so that a bent portion having a large curvature can be easily formed. it can. Japanese Patent Application Laid-Open No. 5-104606 discloses a method of manufacturing a weather strip having a special shape in which the width changes in the length direction. The discharge amount per unit area is always constant even when the extrusion opening area is changed by a movable member. The method is a technique for changing the width of a linear weather strip, and as in the present invention, the width is almost constant in the length direction and the curvature is large. It is not possible to produce a weatherstrip with bent parts (corners and / or sharp corners).

In the present invention, a thermoplastic elastomer composition or a thermoplastic resin composition is used for extrusion molding. The thermoplastic elastomer composition used in the present invention is not particularly limited, and includes, for example, polystyrene (for example, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylenebutylene-styrene block copolymer), Polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polyvinyl chloride-based thermoplastic elastomer compositions, but in terms of heat resistance, durability, and flexibility, the continuous phase is a thermoplastic resin composition, Preferably, the dispersed phase is a thermoplastic elastomer composition wherein the elastomer composition is at least partially dynamically crosslinked.

The thermoplastic resin composition used for the continuous layer of the thermoplastic elastomer composition in which the continuous phase is a thermoplastic resin composition and the dispersed phase is at least partially a dynamically crosslinked elastomer composition is as follows: For example, the following thermoplastic resins and any resin mixtures containing them can be mentioned. Polyolefin-based resins (eg, high density polyethylene (HDPE), low density polyethylene (LDPE),
Ultra high molecular weight polyethylene (UHMWPE), isotactic polypropylene, ethylene propylene copolymer resin), polyamide resin (for example, nylon 6 (N6),
Nylon 66 (N66), Nylon 46 (N46), Nylon 11 (N11), Nylon 12 (N12), Nylon 610 (N610), Nylon 612 (N61)
2), nylon 6/66 copolymer (N6 / 66), nylon 6/66/610 copolymer (N6 / 66/61)
0), nylon MXD6 (MXD6), nylon 6T,
Nylon 6 / 6T copolymer, Nylon 66 / PP copolymer, Nylon 66 / PPS copolymer), polyester resin (for example, polybutylene terephthalate (PBT),
Polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polyester copolymer, P
ET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, aromatic polyester such as polyoxyalkylenediimidic acid / polybutylate terephthalate copolymer),
Polyether resin (for example, polyacetal (PO
M), polyphenylene oxide (PPO), polysulfone (PSF), polyetheretherketone (PEE)
K)), polynitrile resins (eg, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer) , Polymethacrylate resins (eg, polymethyl methacrylate (PMMA), polyethyl methacrylate), polyvinyl resins (eg, vinyl acetate (EVA), polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), Vinylidene chloride (PVDC), polyvinyl chloride (PV
C), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate copolymer), cellulosic resins (eg, cellulose acetate, cellulose acetate butyrate),
Fluorinated resin (for example, polyvinylidene fluoride (PVD)
F), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene /
Examples include ethylene copolymer (ETFE)), imide-based resin (for example, aromatic polyimide (PI)), and polyacetal. Above all, considering cost, coefficient of friction, etc., polyolefin resin, polyamide resin,
Polyester-based resins, polyether-based resins, and fluorine-based resins can be suitably used.

The elastomer composition used for the dispersed phase of the thermoplastic elastomer composition can be, for example, the following elastomers and any mixture containing them. Diene rubbers and hydrogenated products thereof (eg, NR, IR, epoxidized natural rubber, SBR, BR
(High cis BR and low cis BR), NBR, hydrogenated NB
R, hydrogenated SBR), olefin rubbers (eg, ethylene propylene rubber (EPDM, EPM), maleic acid-modified ethylene propylene rubber (M-EPM), IIR, isobutylene and aromatic vinyl or diene monomer copolymer, acrylic rubber (ACM), ionomer), halogen-containing rubber (for example, bromide of Br-IIR, CI-IIR, isobutylene paramethylstyrene copolymer (Br)
-IPMS), CR, hydrin rubber (CHR), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-
CM), silicone rubber (eg, methyl vinyl silicone rubber, dimethyl silicone rubber, methyl phenyl vinyl silicone rubber), sulfur-containing rubber (eg, polysulfide rubber), fluorine rubber (eg, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene) -Propylene rubber, fluorine-containing silicon rubber,
Fluorinated phosphazene-based rubber), urethane rubber, epichlorohydrin rubber, and thermoplastic elastomers (for example, styrene-based elastomer, olefin-based elastomer, ester-based elastomer, urethane-based elastomer, and polyamide-based elastomer). Of these, diene rubbers and hydrogenated products thereof, olefin rubbers, halogen-containing rubbers, fluorine rubbers, urethane rubbers, and epichlorohydrin rubbers can be suitably used in consideration of cost, weather resistance, chemical resistance, and the like.

The combination of the thermoplastic resin composition and the elastomer composition constituting the thermoplastic elastomer composition is not particularly limited, and a composition of at least one thermoplastic resin selected from the above thermoplastic resins, One or more elastomer compositions selected from the above elastomers can be used in combination.

The ratio between the thermoplastic resin composition and the elastomer composition is not particularly limited, but preferably, the thermoplastic resin composition / elastomer composition = 85/15 to 50% by weight.
15/85. In addition, the thermoplastic elastomer composition or the thermoplastic resin composition used in the present invention may contain a water repellent, if necessary. This water repellent reduces the surface tension of the thermoplastic elastomer composition or the thermoplastic resin composition to form a surface layer having good lubricity. Specific examples of the water repellent include a silicone water repellent and a fluorine water repellent. Specifically, dimethylpolysiloxane, dimethyltrimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, etc .; modified polysiloxane such as epoxy-modified, carboxy-modified, alcohol-modified, etc .; polytetrafluoroethylene, tetrafluoroethylene-par Fluoroalkyl vinyl ether copolymer,
Tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkylvinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride And the like. These may be used alone or in combination of two or more.
In the thermoplastic elastomer composition or the thermoplastic resin composition used in the present invention, the content of the water repellent is 0.1.
The amount is from 0.5 to 20% by weight, and preferably from 0.2 to 5% by weight in consideration of the balance between the physical properties of the molded article and the water repellency. When the content of the water repellent is less than 0.05% by weight, the water repellency becomes insufficient, and when the content exceeds 20% by weight,
The physical properties of the molded product are reduced.

The thermoplastic resin composition and / or the elastomer composition may have the object of the present invention in order to improve the fluidity, heat resistance, physical strength, cost and the like of the thermoplastic elastomer composition. Add necessary amounts of compounding agents, such as reinforcing agents, fillers, water repellents, foaming agents, softeners, plasticizers, antioxidants, stabilizers, processing aids, etc., which are added to ordinary compositions, as long as they do not impair. You can also. Further, a pigment can be added to the thermoplastic resin composition for the purpose of coloring or the like.

The vulcanizing agent, vulcanization aid, vulcanization conditions (temperature, time) and the like used for vulcanizing the elastomer composition used in the thermoplastic elastomer composition depend on the composition of the elastomer composition to be added. It may be determined appropriately according to need, and there is no particular limitation. As the vulcanizing agent, a general rubber vulcanizing agent (crosslinking agent) can be used. Specifically, examples of the sulfur-based vulcanizing agent include powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, and alkylphenol disulfide. About 4 phr (parts by weight per 100 parts by weight of the elastomer component (polymer)) may be used.

The organic peroxide-based vulcanizing agents include:
Benzoyl peroxide, t-butyl hydroperoxide, 2,4-dichlorobenzoyl peroxide,
Examples thereof include 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethylhexane-2,5-di (peroxylbenzoate).
About 1 to 15 phr may be used. Further, examples of the phenolic resin-based vulcanizing agent include bromide of an alkylphenol resin, a mixed crosslinking system containing a halogen donor such as tin chloride or chloroprene and an alkylphenol resin, and for example, about 1 to 20 phr is used. I just need.

In addition, zinc white (about 5 phr),
Magnesium oxide (about 4 phr), litharge (10 to 10 phr)
About 20 phr), p-quinone dioxime, p-dibenzoylquinone dioxime, tetrachloro-p-benzoquinone, poly-p-dinitrosobenzene (2 to 10 phr)
Degree) and methylin dianiline (about 0.2 to 10 phr).

[0034] If necessary, a vulcanization accelerator may be added. Examples of the vulcanization accelerator include common vulcanization accelerators such as aldehyde / ammonia, guanidine, thiazole, sulfenamide, thiuram, dithioate, and thiourea, for example, 0.5 to 2 phr. The degree may be used.

In the method for producing the thermoplastic elastomer composition, the thermoplastic resin composition and the elastomer composition (unvulcanized product in the case of rubber) are melt-kneaded in advance by a twin-screw kneading extruder or the like, and the continuous phase ( By dispersing the elastomer composition as a dispersed phase (domain) in the thermoplastic resin composition forming the matrix phase). Next, in order to vulcanize the elastomer composition, a vulcanizing agent is added under kneading, and the elastomer composition is dynamically vulcanized. In addition, various additives to the thermoplastic resin composition or the elastomer composition,
Although it may be added during the kneading, it is preferable to mix them before kneading. At this time, a vulcanizing agent may be mixed in the elastomer composition in advance, and vulcanization may be simultaneously performed during kneading of the thermoplastic resin composition and the elastomer composition. The kneading machine used for kneading the thermoplastic resin composition and the elastomer composition is not particularly limited, and a screw extruder, a kneader, a Banbury mixer, a twin-screw kneading extruder or the like can be used. Among them, it is preferable to use a twin-screw kneading extruder for kneading the thermoplastic resin composition and the elastomer composition and for dynamic vulcanization of the elastomer composition. Further, two or more kinds of kneaders may be used and the kneading may be performed sequentially. As the conditions for the melt-kneading, the temperature may be at least the temperature at which the thermoplastic resin melts. Further, the shear rate at the time of kneading is preferably from 500 to 7500 sec ^-1 . The total kneading time is preferably 30 seconds to 10 minutes, and the vulcanization time after addition is preferably 15 seconds to 5 minutes.

In the present invention, the thermoplastic resin composition used for extrusion molding is the same as that used for the continuous phase of the above-mentioned thermoplastic elastomer composition.

In the present invention, the above-mentioned thermoplastic elastomer composition or thermoplastic resin composition is preferably a foam. The foam is obtained by adding a foaming agent to a thermoplastic elastomer composition or a thermoplastic resin composition, and heating and foaming the composition. Examples of the foaming agent used in the present invention include a physical foaming agent and a chemical foaming agent.
The physical foaming agent is, for example, an inorganic physical foaming agent (for example,
Nitrogen, air, water); aliphatic hydrocarbons (eg, pentane, butane, hexane), chlorinated aliphatic hydrocarbons (eg, methyl chloride, methylene chloride), fluorinated aliphatic hydrocarbons (eg, trichlorofluoromethane, Organic physical foaming agents such as dichlorodifluoromethane, trichlorotrifluoroethane, chlorodifluoroethane, and hydrofluorocarbon). Chemical blowing agents include, for example, inorganic blowing agents (eg, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, ammonium nitrite,
Azide compounds, sodium borohydride); azo compounds (eg, azodicarbonamide, azobisformamide, azobisisobutyronitrile, barium azodicarboxylate), nitroso compounds (eg, N, N′-dinitrosopentamethylenetetramine) , N, N'-dinitroso-N, N'-dimethylterephthalamide), sulfonylhydrazide compounds (eg, benzenesulfonylhydrazide, p-toluenesulfonylhydrazide, p, p
Organic blowing agents such as' -oxybisbenzenesulfonyl hydrazide) and sulfonyl semicarbazide compounds (for example, p-toluenesulfonyl semicarbazide). In the present invention, foamable beads may be used as the foaming agent.

The physical foaming agent gasifies and foams by heating or the like, and the chemical foaming agent generates gas by a chemical change such as thermal decomposition. In the present invention, the foaming agent can be foamed by heating for softening / melting the thermoplastic elastomer composition or the thermoplastic resin composition to contain bubbles.

The bending member manufactured according to the present invention has an advantage of being excellent in strength because the outside of the bending portion is thick. Further, when the thermoplastic elastomer composition or the thermoplastic resin composition used in the present invention is a foam, in order to reduce the number of revolutions of the extruder at a bent portion, the material temporarily stays in the extruder. The time gets longer. During this time, the foaming gas partially escapes out of the system, so that the foaming ratio decreases at the bend where the molding speed is slowed, and the strength of the bend can be maintained. Therefore, it is preferable that the thermoplastic elastomer composition or the thermoplastic resin composition is a foam because the weight of the bent member can be reduced while maintaining excellent strength of the bent portion.

The method for manufacturing a bent member according to the present invention can be widely used for manufacturing a weather strip, a hose, and other bent members having a bent portion. However, a bent member having a bent portion having a large curvature can be manufactured. In this regard, one preferred embodiment is used for the production of weatherstrips. Further, it is preferable in that the number of work steps is small and the work cost can be reduced as compared with the conventional weather strip manufacturing method.

A second aspect of the present invention is a weatherstrip manufactured by the method for manufacturing a bent member. ADVANTAGE OF THE INVENTION The weatherstrip of this invention is excellent in the intensity | strength of a bending part. In particular, it is preferable to use a foamed material because the weight can be reduced without lowering the strength of the bent portion. Also, compared to conventional weatherstrips,
It is also preferable in that it can be manufactured at low cost.

The use of the weatherstrip of the present invention is not particularly limited, and it is suitably used for weatherstrips for automobiles such as doors, roofsides, sunroofs, drips, trunk lids, and glass runs.

[0043]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. 1. Preparation of Thermoplastic Elastomer Composition First, the raw materials shown in the column of the elastomer composition in Table 1 were charged into rubber bumpers at respective weight ratios, kneaded for 3 minutes, and then released. The obtained elastomer composition was pelletized using a rubber pelletizer. Next, the thermoplastic resin and the elastomer composition were dry-blended at the compounding ratio (weight ratio) shown in Table 1 and the first mixture was placed in a twin-screw kneading extruder.
Feed from the feeder, disperse the elastomer composition in the resin while heating and melting with a twin screw, then add the vulcanizing system and water repellent, crosslink the elastomer composition under kneading and thermoplastic An elastomer composition was obtained. The kneading conditions were a temperature of 200 to 250 ° C., a shear rate of 1000 sec ⁻¹ , a total melt-kneading time of about 3 minutes, and a cross-linking time after adding the vulcanization system of about 1 minute.

(1) Thermoplastic resin Nylon 6/66 copolymer (nylon 666): CM
6001, Toray's polypropylene: MS230, Tokuyama's (2) Elastomer composition Acrylonitrile-butadiene rubber (NBR): Ni
pol 1043, ethylene-propylene-diene rubber (EPDM) manufactured by Zeon Corporation: E
PT4070, carbon black (HAF grade) manufactured by Mitsui Chemicals, Inc .: Seast 3, dioctyl phthalate (DOP) manufactured by Tokai Carbon Co., Ltd. paraffin oil: machine oil 22, manufactured by Showa Shell Sekiyu KK (3) vulcanized sulfur: Sulfur powder, Karuizawa Refining Co., Ltd. Zinc flower: Zinc flower No. 3, Shodo Chemical Co., Ltd. Stearic acid: Beads stearic acid, Nippon Yushi Co., Ltd. Brominated phenolic resin: Tackilol 250-I, Taoka Chemical Co., Ltd. (4 ) Water repellent dimethyltrimethylpolysiloxane: DCQFI-35
93A, manufactured by Toray Silicone Co., Ltd. (5) Blowing agent Azodicarbonamide: Uniform AZ Ultra # 1
100, manufactured by Otsuka Chemical Co., Ltd.

2. Manufacture of weather strip (Example 1) φ4 with a die having the shape shown in FIG. 2 attached to the tip
Using a 0 mm single screw extruder, the thermoplastic elastomer composition obtained above was extrusion-molded to produce a weatherstrip having a shape shown in FIG. 4A (the cross-sectional shape was FIG. 5). Extrusion molding was performed by the mechanism shown in FIG. 3, and molding conditions were controlled as shown in FIGS. 4 (B) and 4 (C). (Example 2) A weather strip was produced in the same manner as in Example 1 except that a different thermoplastic elastomer composition was used. (Example 3) A weather strip was prepared in the same manner as in Example 2, except that the thermoplastic elastomer composition was dry-blended with a foaming agent in advance and used. (Comparative Example 1) The same thermoplastic elastomer composition as in Example 3 was extruded using a head having a die and a pin whose relative positions could not be changed to obtain a linear extrudate. After extrusion, it was press-fitted into a mold composed of an outer mold and a middle mold so as to have the same shape as in Examples 1 to 3, and heated to perform habituation. Finally, the middle mold was removed to obtain a weatherstrip.

3. Physical property test, etc. A strength test was performed on the obtained weather strip. In the strength test, a (linear portion) and d shown in FIG.
Each part of the (bent part) was cut out from the weather strip obtained above, and the tensile strength was measured by an autograph. For Example 3 and Comparative Example 1, the expansion ratio was measured. The expansion ratio is in accordance with JIS K7222.
The foam density was measured and converted to an expansion ratio. In addition, the number of man-hours required for fabricating the weather strip was compared.

The results are shown in Table 1. The number of working steps is shown as a relative value with Comparative Example 1 being 100. It can be seen that the method of manufacturing a bent member of the present invention (Examples 1 to 3) has an advantage that the number of working steps is significantly smaller than that of a conventional method of manufacturing a weather strip (Comparative Example 1). This is because, according to the method for manufacturing a bent member of the present invention, a bent member having a bent portion having a large curvature such as a weather strip can be manufactured only by extrusion molding, and the customization after extrusion is unnecessary. Further, it can be seen that the weatherstrip of the present invention (Examples 1 and 2) obtained by the method for manufacturing a bent member of the present invention has a bent portion having the same strength as a straight portion. This is because, according to the method for manufacturing a bent member of the present invention, the outside of the bent portion becomes thick. In particular, when the thermoplastic elastomer composition or the thermoplastic resin composition is a foam (Example 3),
It can be seen that since the foaming ratio is reduced at the bend where the molding speed is slow, the weight can be reduced while improving the strength of the bend where the stress is concentrated.

[0048]

[Table 1]

[0049]

The method for manufacturing a bent member according to the present invention is a method capable of manufacturing a bent member having a bent portion having a large curvature only by extrusion molding without requiring molding, and is suitable for manufacturing weather strips, hoses and the like. Used for Moreover, the weatherstrip of the present invention obtained by the method for manufacturing a bent member of the present invention has excellent durability at the bent portion, and thus has sufficient durability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of the concept of a head used in a method for manufacturing a bent member according to the present invention.

FIG. 2 is an example of a head shape suitably used in the method for manufacturing a bent member of the present invention, which is a head shape used in an embodiment of the present invention.

FIG. 3 is a conceptual diagram showing one embodiment of a bending member manufacturing apparatus for performing the bending member manufacturing method of the present invention.

FIGS. 4A and 4B are diagrams illustrating (A) a shape of a weather strip, (B) a position (amount of movement) of a pin 3, and (C) a rotation speed of an extruder 8 when a weather strip abcdea is manufactured by a bending member manufacturing apparatus 7. FIG.

FIG. 5 is a cross-sectional view of an example of the weather strip of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Head 2 Die 3 Pin 4 Thermoplastic elastomer composition or thermoplastic resin composition 5 Pin taper 6 Die inner surface taper 7 Bending member manufacturing apparatus 8 Extruder 9 Actuator 10 Control panel

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masuda Kuroda 2-1 Oiwake, Hiratsuka-shi, Kanagawa F-term in the Hiratsuka Factory of Yokohama Rubber Co., Ltd. (Reference) 3D024 AA06 AA27 AB33 AB41 AB57 4F207 AA45 AG20 AH23 AR07 AR14 AR15 KA01 KA11 KF01 KK07 KL62 KM15

Claims (4)

[Claims] 1. A method for producing a bent member using a head having a die and a pin capable of changing a positional relationship between each other in extrusion molding of a thermoplastic elastomer composition or a thermoplastic resin composition, A method for manufacturing a bent member, wherein a positional relationship between a die and a pin and an extrusion amount are controlled in conjunction with each other. 2. The method according to claim 1, wherein the thermoplastic elastomer composition or the thermoplastic resin composition is a foam. 3. The thermoplastic elastomer composition according to claim 1, wherein the continuous phase is a thermoplastic resin composition, and the dispersed phase is at least partially a dynamically crosslinked elastomer composition. Item 3. The method for manufacturing a bent member according to Item 1 or 2. 4. A weather strip manufactured by the method for manufacturing a bent member according to claim 1.