JPH06106601A - Method and device for extruding short fiber-inclusion elastomer - Google Patents

Abstract

PURPOSE:To provide a constant feeding of a feeding mechanism without technical difficulties and working complexities by shredding sheet elastomer which has been formed by milling into a granulated form, and by bonding anti-adhesion poker to the surfaces of the shredded elastomer to make material for extrusion. CONSTITUTION:Raw material rubber and short fiber that form matrix for elastomer are kneaded by a kneader 2 to make short fiber-included rubber 1a in an ingot form. The rubber 1a is milled by an open roll 3 to form raw material 1b in a continuous sheet form, and at the same time, it is introduced to a net multistage batch off machine 4 as it is, and the rubber sheet 1b is cooled to normal temperatures by a cool air machine, etc. Further, it is shredded by a pelletizer 5 to make rubber 1c in a form of pellets. Finally, by using a power- bonding mayor 6 the rubber 1c in the pellet form is bonded with the anti- adhesion powder, zinc stearate powder (mixing volume e.g. 15g/60g), to prevent mutual adhesion among pellets of rubber 1c, and parts of the screw members etc., at the time of extrusion molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an extrusion method and an extrusion apparatus for performing extrusion molding using a short fiber mixed elastomer obtained by mixing short fibers in an elastomer such as rubber.

[0002]

2. Description of the Related Art Conventionally, when a short fiber mixed rubber obtained by mixing short fibers into a rubber which is an elastomer is used as a raw material and extrusion molding is carried out using a screw type extruder,
The kneaded rubber supplied to the extruder is usually 5 to 8 mm in thickness,
It is a ribbon-shaped rubber with a width of about 5 to 10 mm. Then, the specific step is to wind the sheet-shaped kneaded rubber around the open roll, cut the ribbon-shaped rubber from the sheet-shaped rubber with two cutter knives, and pass the ribbon-shaped rubber through the aqueous solution containing the release agent. Then, it is passed through a batch-off machine, cooled and dried to be used as the material to be supplied to the extrusion equipment. An apparatus for producing such material ribbon is
It is already on the market (for example, "Ribbon Ace" manufactured by Suzuka Engineering Co., Ltd.), and the ribbon-shaped rubber created in such a process is put into the hopper attached to the raw material inlet of the extruder and screw-shaped feed from the inlet. The feeding mechanism is used to feed the ribbon into the barrel.

[0003]

However, when the conventional manufacturing method described above is adopted when extrusion molding is performed using a rubber containing short fibers as a raw material, there are the following problems.

First, even if a kneaded rubber is wrapped around an open roll and cut with a cutter knife, short fibers, which are more difficult to cut than rubber, gather at the blade edge of the knife and hinder the cutting. Have difficulty. Also, even if it can be cut into a ribbon shape, the ribbon will be in a state of being adhered to the open roll, and especially since chloroprene rubber that is usually used as a matrix of short fiber mixed rubber has a strong adhesive force to the roll, it is difficult to peel the ribbon. There's a problem. That is, although the temperature is slightly increased in this step (for example, about 70 to 80 ° C.), in the case of the rubber mixed with short fibers, when the temperature is about 60 ° C. or higher, the rubber is plasticized and the tear strength is extremely lowered, and the ribbon is The ribbon itself could be torn off when peeled off. In addition, there is a problem that the work of supplying the rubber to the cutout portion where the rubber decreases when cut with an open roll becomes very complicated with the rubber containing short fibers.

[0005] On the other hand, a method of stacking sheet-shaped ribbons using a guillotine or a shearing machine can be considered, but it is difficult to cut out long ribbons, and the process becomes very complicated.

Secondly, rubber may crystallize depending on conditions, and chloroprene is particularly likely to crystallize. Therefore, if the ribbon-shaped sheet is folded and crystallized when it is stored, it becomes difficult to remove the folding habit, it is difficult to put it in the hopper of the extruder, and it is necessary to reheat it.

Thirdly, in the case of ordinary rubber containing no short fibers, when a ribbon-shaped raw material is supplied to the raw material feeding port of the extruder, a screw-like material disposed inside the raw material feeding port is provided from the tip end side of the ribbon. By being bitten into the feeding mechanism and pulling the rear portion, the portion that was previously fed is smoothly fed into the barrel of the extrusion device.However, in the case of short fiber mixed rubber, as described above, it is plastic at high temperatures. And the tear strength decreases, so that the sheet cannot be smoothly fed. That is, when the temperature of the input rubber rises in the screw-shaped feeding mechanism, the ribbon is torn by plasticization, so that the portion previously engaged in the screw-shaped feeding mechanism cannot obtain the action of pulling the latter portion, The unfilled part of the ribbon is not plasticized because it is at room temperature, and as a result of being continuously fed to the screw-shaped feeding mechanism side, the rubber plasticized through the screw-shaped feeding mechanism stays in the raw material feeding port. Eventually the raw material input port is blocked. For this reason, the supply of rubber is interrupted in the middle, the discharge speed of the extruded rubber is non-uniform, and the rubber pressure on the tip side of the extruding device varies, making it difficult to obtain the desired quality. If it is attempted to avoid this, it is necessary to supply the ribbon while observing the state of retention of the ribbon-shaped rubber at the raw material input port of the extruder, which is extremely complicated in terms of work.

According to the present invention, the above-mentioned problem is solved by assuming that the ribbon-shaped elastomer is used as an extrusion molding material for continuous feeding of the material, while the ribbon is plasticized at a high temperature in the screw-shaped feeding mechanism. It was made by paying attention to the fact that it is caused by cutting and cutting, and the short fiber mixed elastomer is granulated and extruded using this as a material, that is, the elastomer itself supplied to the screw-like feeding mechanism. The object is to smoothly perform extrusion molding using a short fiber mixed elastomer as a raw material by making the non-continuous shape.

[0009]

In order to achieve the above-mentioned object, the means of the invention of claim 1 is to extrude a short fiber-containing elastomer by extrusion molding using a short fiber-containing elastomer such as rubber as a raw material. As a method, as shown in FIG. 1, a step of kneading short fibers into an elastomer, a step of rolling the short fiber-containing elastomer into a sheet shape, and a step of shredding the sheet-like elastomer formed by rolling into particles. And a step of adhering the adhesion-preventing powder on the surface of the granular elastomer formed by shredding to obtain a material for extrusion.

As shown in FIG. 2, the means taken by the invention of claim 2 is a short fiber in which a short fiber mixed elastomer product having a predetermined shape is produced by extrusion molding using a granular short fiber mixed elastomer as a raw material. Intended for extrusion equipment of mixed elastomers.

Then, a hopper member into which the granular elastomer is charged, a transport mechanism for transporting the granular elastomer charged into the hopper member to a raw material charging port, and a granular elastomer in the raw material charging port which is arranged in the raw material charging port. The configuration is such that detection means for detecting the presence / absence and control means for performing on / off control of the operation of the transport mechanism according to the detection of the detection means are provided.

[0012]

According to the first aspect of the present invention, when the short fiber-containing elastomer is extruded by the above-mentioned method and extruded, the short fiber-containing elastomer is granular, so that it is technically difficult to form the ribbon-like material. It is possible to create an extrusion molding material without inviting the complexity of the sheath.

By extrusion molding using this granular elastomer, even if the granular elastomer supplied to the screw-shaped feeding mechanism in the raw material charging port of the extruder is plasticized in the screw-shaped feeding mechanism, it is cut. In addition, since the adhesion-preventing powder is adhered to the surface, the material can be smoothly fed to the barrel without hindering the feeding in the screw-shaped feeding mechanism. Therefore, a substantially constant feed amount can be secured without causing the problems that occur when a ribbon-shaped material is used.

According to the second aspect of the invention, with the above configuration,
In the extruder, the presence or absence of the granular material is detected by the detection means provided at the raw material input port, and the feeding status of the granular material by the screw-shaped feeding mechanism is accurately grasped. The control means controls the transport mechanism to stop when there is granular material in the raw material input port and to operate the transport mechanism when there is no granular material in the raw material input port. The supply amount is made uniform without causing excessive supply or insufficient supply of the granular material.

[0015]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 shows a step of producing a granular material of short fiber mixed elastomer in the embodiment, that is, a pelletized material. First, a kneader 2 is used to knead a raw material rubber to be an elastomer matrix and short fibers to form an ingot shape. The short fiber mixed rubber 1a is used.

Then, the ingot-shaped rubber 1a is rolled by an open roll 3 into a sheet-shaped raw material 1b, which is continuously guided to a conveyer of a net multistage batch-off machine 4 and is cooled by a cool air blower or the like. Cool 1b to room temperature. In addition, in this batch off machine 4,
One kneading amount in the kneader 2 is stored.

Further, the cooled sheet rubber 1b is shredded into pellet rubber 1c by a pelletizer 5. As the pelletizer 5, one manufactured by Sanriki Seisakusho is used, and circular teeth having widths on the left and right are alternately interlocked and rotated. When the sheet rubber 1b enters the circular teeth, first. After being cut into strips having the same width as the circular teeth, the strip is cut into strip-shaped rubber, that is, pellet-shaped rubber 1c from the strip with the next rotating tooth. The shredding speed at this time is, for example, 15 pieces / min, the pelletizer 5 can be directly connected to the batch-off machine 4, and the sheet rubber 1b once stored is supplied to the pelletizer 5. You may do it.

Finally, using a powdering mixer 6, zinc stearate (zinc stearate, magnesia, etc.) powder, which is an anti-adhesion powder, is adhered to the pelletized rubber 1c (mixing amount is, for example, 15 g / About 60 kg),
Adhesion between the pellet-shaped rubbers 1c and adhesion to a screw member or the like during extrusion molding are prevented.

FIG. 2 shows an outline of an extrusion apparatus 10 for performing extrusion molding using the pellet-shaped rubber 1c produced in the above process as a raw material. A raw material charging port 11 for charging a raw material is opened in the extrusion device 10. Although not shown, the cylindrical barrel 1 is provided inside the raw material charging port 11.
6 and a screw-shaped feeding mechanism 15 that is provided in the barrel 16 and that feeds the raw material from the raw material inlet 11 to the extrusion section.
And are provided. Further, a hopper 12 for charging the pellet rubber 1c and a hopper screw 13 which is a conveying means for conveying the pellet rubber 1c from the hopper 12 to the raw material charging port 11 are provided. Also,
A pair of photoelectric tubes 14a and 14b as detection means for detecting the presence or absence of the pellet-shaped rubber 1c are arranged at a part in front of the screw-shaped feeding mechanism 15 in the raw material charging port 11. That is, the pellet-shaped rubber 1c charged into the hopper 12 is conveyed to the raw material charging port 11 via the hopper screw 13, but the photoelectric tubes 14a and 14b
Detects whether or not the pellet-shaped rubber 1c exists before the screw-shaped feeding mechanism 15 that feeds the pellet-shaped rubber 1c to the barrel, and if the pellet-shaped rubber 1c exists, the raw material is in the screw-shaped feeding mechanism. There are many in
While the operation of the hopper screw 13 is stopped, if the pellet-shaped rubber 1c is not present in front of the screw-shaped feeding mechanism, it is determined that the raw material is insufficient in the screw-shaped feeding mechanism 15, and the hopper screw 13 is driven. I am trying. This control constitutes the control means according to the invention of claim 2.

Therefore, in the above-mentioned embodiment, when extrusion molding is performed using rubber as the raw material, the short fiber mixed rubber is used as the pellet-shaped rubber 1c. It is possible to produce an extrusion molding material without causing a problem.

Further, by extruding the pellet-shaped rubber 1c, it is possible to avoid a problem in the screw-shaped feeding mechanism 15 in the extrusion device 10 that occurs when a ribbon-shaped rubber is used. That is, when the ribbon-shaped rubber is supplied as the material, the material is continuously supplied to the screw-shaped feeding mechanism 15, but in the screw-shaped feeding mechanism 15, the temperature is high and the material is plasticized. The tearing of the ribbon makes it difficult to feed the material smoothly into the barrel. On the other hand, when the pellet-shaped rubber 1c is used as the material for extrusion, the screw-shaped feeding mechanism 1 is used.
Even if the pellet-shaped rubber 1c supplied to No. 5 is plasticized in the screw-shaped feeding mechanism 15, the pellet-shaped rubber 1c does not enter the screw groove and is not clogged. Since zinc stearate) is attached, the material can be smoothly supplied to the barrel without causing any obstruction of the screw-shaped feeding mechanism 15. Therefore, a substantially constant feed amount can be secured, and the quality of the extruded product can be favorably secured.

Further, in the extruder 10, the phototubes 14a and 14b are provided in the raw material inlet 11, and the presence or absence of the pellet rubber 1c is judged by the phototubes 14a and 14b. The feeding status of the rubber 1c is accurately grasped. Then, the control means stops the hopper screw 13 when the pellet-shaped rubber 1c is present in the raw material input port 11, and the raw material input port 1
Since the hopper screw 13 is controlled to operate when the pellet-shaped rubber 1c does not exist in 1, there is no excessive supply or insufficient supply of the pellet-shaped rubber 1c to the barrel by the screw-shaped feeding mechanism 15, and the supply amount Can be made uniform.

[0024]

As described above, according to the invention of claim 1, as a method for extruding rubber containing short fibers, short fibers are kneaded with an elastomer, and the short fiber mixed elastomer is rolled into a sheet, and then a sheet is formed. The granular elastomer is shredded into particles, and the adhesion-preventing powder is adhered to the surface of this granular elastomer, and extrusion molding is performed using this granular elastomer. It is possible to secure a constant feed rate without causing technical difficulties and work complexity, and without disturbing the feed of the material in the screw-like feed mechanism of the extrusion device. It is possible to improve the quality of the extrusion molded product of the mixed elastomer.

According to the invention of claim 2, as the constitution of the extrusion device for extruding the granular short fiber mixed elastomer as the raw material, the granular elastomer is conveyed from the hopper member into which the granular elastomer is charged to the raw material charging port of the extruder. While the transport mechanism is installed, the presence / absence of granular elastomer in the raw material inlet is detected and the operation of the transport mechanism is controlled to be turned on / off depending on the presence / absence of the granular elastomer. The feeding mechanism can be controlled while accurately grasping the feeding status to the extruding section, and the feeding amount can be made uniform without causing excessive feeding or insufficient feeding of the granular elastomer.

[Brief description of drawings]

FIG. 1 is a view showing a pellet manufacturing process of a short fiber mixed elastomer according to an example.

FIG. 2 is a perspective view schematically showing a configuration of a short fiber extrusion device according to an example.

[Explanation of symbols]

 1a Ingot rubber 1b Sheet rubber 1c Pellet rubber 2 Kneader 3 Open roll 4 Batch off machine 5 Pelletizer 6 Powder mixer 10 Extruder 11 Raw material inlet 12 Hopper 13 Hopper screw (Conveying mechanism) 14a, 14b Photocell (Detecting means) ) 15 Screw-shaped feeding mechanism

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area // B29K 21:00 105: 12

Claims (2)

[Claims] 1. A method for extruding a short fiber-containing elastomer, which comprises extruding a short fiber-containing elastomer such as rubber as a raw material, the method comprising kneading the short fiber into the elastomer, and forming the short fiber-containing elastomer into a sheet form. Rolling, a step of shredding the sheet-like elastomer formed by rolling into granules, and a step of adhering anti-adhesion powder to the surface of the granular elastomer formed by shredding to form a material for extrusion. A method for extruding a short fiber-containing elastomer, comprising: 2. A short fiber-containing elastomer extruding apparatus for producing a short fiber-containing elastomer product having a predetermined shape by extrusion molding using a granular short fiber-containing elastomer as a material, and a hopper member into which the granular elastomer is charged. A transport mechanism for transporting the granular elastomer charged into the hopper member to a raw material charging port, a detection unit arranged at the raw material charging port for detecting the presence or absence of the granular elastomer in the raw material charging port, and a detecting unit for detecting the detecting unit. Accordingly, a short fiber mixed elastomer extruding device comprising: a control means for controlling on / off of the operation of the transport mechanism.