JP2005053190A - Method for producing kneaded material and apparatus used in the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously and efficiently produce a kneaded material which can improve the dispersion and distribution properties of a chemical and is excellent in uniformity. <P>SOLUTION: Rubber G sent quantitatively from a rubber supply means 2 and the chemical C sent quantitatively from a chemical supply means 3 are charged simultaneously into a first single screw type rubber extruder 4 to knead primarily kneaded rubber G1. After that, the primarily kneaded rubber G1 is further kneaded by a second twin taper screw type rubber extruder 5 to form the kneaded material G0. The spiral pitch P of the taper screw shaft 31 of the second rubber extruder 5 is made to be 1.1-1.5 times as large as the diameter d on the large diameter side of the taper screw shaft 31. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a kneaded body manufacturing method capable of continuously and efficiently manufacturing a kneaded body in which rubber and chemicals are uniformly dispersed, and an apparatus used therefor.

  Known devices for kneading kneaded rubber with chemicals such as vulcanizing agents and vulcanization accelerators include, for example, hermetic mixers such as Banbury mixers and uniaxial or biaxial screw rubber extruders. ing.

  Among these, the closed mixer is kneaded in a closed system, so that it is possible to uniformly disperse the chemical throughout the kneaded body and to form a high-quality kneaded body. is there. However, in a closed mixer, since a large amount of rubber is kneaded at a time, a calorific value is large, and a rubber composition having a low vulcanization temperature may cause burning during kneading. In addition, until the kneading is finished, the next step, for example, the lump kneading from the hermetic mixer is used as a material for feeding into the final rubber product molding extruder (referred to as a product extruder for convenience). It is necessary to stop and wait for the process of forming the body into a strip-like strip or pellet, causing a reduction in production efficiency. In addition, since a kneaded body of the same composition is formed in a large amount at a time, there is a problem that the material stock becomes excessive particularly in the manufacture of tires that have a strong tendency to produce a variety of products in small quantities.

  Therefore, in recent years, it has been proposed to continuously form a kneaded body using a screw type rubber extruder. However, since this is kneaded while being continuously extruded in a single cylinder, the chemicals are dispersed to some extent uniformly in the cross-sectional direction of the cylinder, but the mixing ratio in the extrusion direction is coarse. As a result, the uniformity of distribution is inferior, and the quality of the kneaded body is impaired as compared with a closed mixer. In addition, since the conveyance efficiency by a screw shaft differs between rubber | gum and a chemical | drug | medicine, even when a chemical | medical agent is continuously injected | thrown-in with a uniform distribution ratio, the fluctuation | variation of a distribution ratio will be caused in an exit.

Japanese Patent Laid-Open No. 60-15110

  Accordingly, in the present invention, the primary kneading is performed by the first rubber extruder of the single screw type, and then the second kneading is performed by the second rubber extruder of the biaxial taper screw type, and the helical pitch P of the tapered screw shaft is specified. A method for producing a kneaded body of a kneaded body that can improve the dispersibility and dispersibility of chemicals and can produce a kneaded body with excellent uniformity continuously and efficiently, and an apparatus used therefor It is intended to provide.

In order to achieve the above object, the invention of claim 1 of the present application is a kneaded body manufacturing method for manufacturing a kneaded body of rubber and chemicals,
The rubber sent quantitatively from the rubber supply means and the chemical sent quantitatively from the chemical supply means are simultaneously put into a single screw type first rubber extruder and kneaded to form the first kneaded rubber as the first kneaded rubber. A primary kneading step continuously extruded from a rubber extruder;
The primary kneaded rubber is put into a biaxial taper screw type second rubber extruder, and further includes a secondary kneading step of further kneading the primary kneaded rubber and extruding a kneaded body from the second rubber extruder. With
The second rubber extruder is characterized in that the helical pitch P of the taper screw shaft is 1.1 to 1.5 times the diameter d on the large diameter side of the taper screw shaft.

The invention of claim 2 is an apparatus for producing a kneaded body for producing a kneaded body of rubber and chemicals,
Rubber supply means for quantitatively supplying the rubber;
A medicine supply means for quantitatively supplying the medicine;
The rubber supply means, the rubber supplied simultaneously from the chemical supply means, the first rubber extruder of the single screw type, which kneads the chemical and continuously extrudes it as the primary kneaded rubber;
And further comprising a biaxial taper screw type second rubber extruder for further kneading the primary kneaded rubber and extruding the kneaded body,
The second rubber extruder is characterized in that the helical pitch P of the taper screw shaft is 1.1 to 1.5 times the diameter d on the large diameter side of the taper screw shaft.

  Since the present invention is configured as described above, the dispersibility and dispersibility of the chemical can be improved, and a kneaded body excellent in uniformity can be produced continuously and efficiently.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing a production apparatus for carrying out the method for producing a kneaded body of the present invention.
In FIG. 1, a kneaded body manufacturing apparatus 1 includes a rubber supply means 2 for quantitatively supplying rubber G, a chemical supply means 3 for quantitatively supplying chemical C, and the rubber G and chemical C are kneaded. It comprises at least a first rubber extruder 4 that continuously extrudes as the primary kneaded rubber G1, and a second rubber extruder 5 that further kneads the primary kneaded rubber G1 and continuously extrudes it as a kneaded body G0. The

  Here, the rubber G is a plastic raw rubber kneaded by a hermetic mixer as is well known, and in this example, a long strip Gs having a constant width and thickness is used. . The strip Gs can be formed by forming a raw rubber from a closed mixer or the like into a sheet with, for example, a sheeting roll and cutting it to a certain width with a slitter or the like, or extruding with a strip forming extruder. If the width and thickness vary, the amount of rubber G to be supplied fluctuates, so that the compounding ratio of the chemical C itself becomes unstable, making it difficult to obtain a high-quality kneaded body G0.

  Further, as the medicine C, powder, granule and pellets can be used. In particular, the so-called rubber masterbatch pellet in which rubber is appropriately blended with medicine has little adhesion to the surface of the medicine supply means 3, Further, it can be preferably used because there is little adhesion and aggregation between chemicals. In addition, as a pellet of a rubber masterbatch, the thing of 0.01g-1.0g is suitable.

  Next, the rubber supply means 2 of the manufacturing apparatus 1 in this example transports the roll stand 6 that holds the roll body R of the strip Gs and the strip Gs that is rewound from the roll body R to the downstream side. A conveyor 7, measuring means 8 for measuring the weight of the transported strip Gs in a reference length unit, and a supply conveyor 9 for supplying the weighted strip Gs to the first rubber extruder 4 are provided.

  In this example, the rubber supply means 2 quantitatively sends the strip Gs to the first rubber extruder 4 by feeding the strip Gs having a constant cross-sectional shape and continuous in the length direction at a constant speed. Can be supplied. The strip Gs can be cut in units of a reference length and intermittently supplied in a fixed amount with the cut piece as a unit.

  The measuring means 8 has a well-known weighing scale with a conveyor, measures the weight of the reference length unit of the strip Gs moving on the weighing scale, and outputs it to the control means 10. When measuring the continuous strip Gs as in this example, in addition to the weighing scale, a speedometer for measuring the moving speed of the strip Gs, for example, a rotary encoder is provided, and the moving speed and the reference length unit are measured. The weight is output to the control means 10, and the substantial supply amount of the rubber to be supplied quantitatively is calculated.

  Next, in this example, the medicine supply means 3 stores, for example, a storage hopper 11 having a capacity of about 50 liters for storing the medicine C, and a capacity for receiving the medicine C conveyed from the storage hopper 11 via the transport pipe 12. A weighing hopper 13 of about 0.3 liters, a measuring means 14 for measuring the weight of the chemical C sent to the weighing hopper 13, and a supply pipe 15 for supplying the weighted chemical C to the first rubber extruder 4 With. The storage hopper 11 is provided with measuring means 16 for measuring the storage amount of the medicine to be stored, and manages the storage amount between the upper limit value and the lower limit value. The measuring means 16 may be a weighing scale or a level meter that measures the level height of the upper surface of the medicine.

  In addition, a feeder such as an electromagnetic vibration type or a screw type is disposed in the transport pipe 12, and the medicine C in the storage hopper 11 is gradually transferred to the weighing hopper 13.

  The measuring means 14 is a weigh scale, and measures the weight of the medicine C transferred to the weighing hopper 13 and outputs it to the control means 10. And the control means 10 operates the said feeder until the chemical | medical agent weight in the said measurement hopper 13 reaches the supply amount corresponding to the rubber supply amount measured by the said measurement means 8. FIG. The chemical supply amount corresponding to the rubber supply amount is calculated from a preset blending ratio of the rubber and the chemical in the kneaded body.

  Similarly to the transfer pipe 12, the supply pipe 15 is provided with a feeder such as an electromagnetic vibration type or a screw type, and a chemical C having a weight corresponding to the rubber supply amount is supplied to the rubber G from the rubber supply means 2. At the same time, it is supplied to the first rubber extruder 4. At this time, in order to more uniformly distribute and supply the chemical C and to improve the uniformity of the kneaded body, it is preferable to set the supply cycle of the chemical C in the range of 1 to 10 seconds.

  Next, the first rubber extruder 4 is a so-called single-screw extruder, and a screw shaft 22 is placed in a cylinder 21 provided with an insertion port 21a into which rubber G and chemical C are introduced simultaneously. Contained well-known structure. Then, by the rotation of the screw shaft 22 by the electric motor, the charged rubber G and the chemical C are pushed forward while being kneaded, and are continuously discharged from the discharge port 23 at the front end as the primary kneaded rubber G1 (primary kneading step).

  Here, the main purpose of the first rubber extruder 4 is to knead the rubber G and the chemical C, which are quantitatively introduced simultaneously, so as to be surely set in the reference length unit. Especially, high mixing performance is not required. Therefore, as shown in FIGS. 3 and 4, in addition to using a general-purpose rubber extruder in which the ratio L / D between the outer diameter D and the length L of the screw shaft 22 is larger than 10, as in this example. It is also possible to use a short rubber extruder having the ratio L / D of 4 to 10, more preferably 4 to 8.

  Next, the second rubber extruder 5 is a so-called biaxial taper screw type extruder, and as shown in FIGS. 2A and 2B, the casing 30 and the casing 30 are rotated. And two tapered screw shafts 31 supported horizontally. The primary kneaded rubber G1 supplied from the charging port 30a is further kneaded by the rotation of the tapered screw shaft 31 by an electric motor, and continuously discharged as a kneaded body G0 from the discharge port 30b at the front end (secondary kneading step). ).

  At this time, the primary kneading rubber G1 is charged by separating the discharge port 23 and the charging port 30a without directly connecting the extruders 4 and 5, and the primary kneading rubber G1 from the discharge port 23 is used in the present example. As shown in FIG. 3, it is preferable that the material is naturally dropped or, after being transported through the conveyor 32 as shown in FIG. This increases the chance that the portion discharged first and the portion discharged later in the primary kneaded rubber G1 will be mixed, that is, the opportunity to mix before and after the time axis direction of kneading increases. Can be increased. The primary kneaded rubber G1 can be fed into the second rubber extruder 5 in the form of a continuous strip. However, it is possible to further improve the distribuability by sequentially cutting at the discharge port 23 and feeding in the pellet state. Preferred above. In addition, the diameter in the case of a pellet has the preferable range of 10-30 mm.

  In the second rubber extruder 5, the taper screw shafts 31 are arranged in a horizontal plane so that the shaft centers approach each other toward the front end, and are formed around the base shaft portion 31a of the taper screw shaft 31. The direction of the spiral of the blade 31b to be rotated and the direction of rotation are different between the taper screw shafts 31 and 31.

  Particularly important in the second rubber extruder 5 is that the helical pitch P of the blade 31b is in a range of 1.1 to 1.5 times the diameter d on the large diameter side of the taper screw shaft 31. It is to be.

  Here, in the first screw extruder 4 of the single screw type, rubber is wound between the blades of the screw shaft 22, and the kneading proceeds by the torsional rotation of the rubber between the blades and the large rotation with respect to the screw shaft 22. Therefore, the range of mixing before and after the kneading time axis is very small, and the distribution is poor.

  On the other hand, in the second rubber extruder 5 of the biaxial taper screw type, the rubber between the blades is radially outward by the rotation of the taper screw shaft 31 rather than being wound around the blades and sequentially fed forward. The kneading proceeds while the mutual movement between the taper screw shafts 31 and 31 is repeated, such as being taken in and kneaded by the taper screw shaft 31 on the other side. Therefore, this movement greatly expands the range of mixing, and not only dispersibility but also distribution can be greatly enhanced.

  However, when the ratio P / d between the helical pitch P and the diameter d is less than 1.1, rubber is easily caught in the blade, and movement between the taper screw shafts 31 and 31 is suppressed. Is not expected. On the other hand, when the ratio P / d exceeds 1.5, it hardly moves forward, and the necessary extrusion amount cannot be secured.

  The kneaded body G0 from the second rubber extruder 5 is discharged in a continuous strip state or discharged while being sequentially cut into a pellet state in order to use as a material to be charged into the product extruder. be able to. In the case of a strip, it is usually wound on a reel by a winding device and stored once, but it may be put into a product extruder as it is without being wound.

  Further, in the manufacturing apparatus 1, in order to further improve the uniformity of the kneaded body G0, a third rubber extruder 33 is arranged on the downstream side of the second rubber extruder 5, as shown in FIGS. Can be set. This third rubber extruder 33 is a uniaxial screw type similar to the first rubber extruder 4 in this example, and when using a total of three extruders, the first and third rubber extruders 33 are used. As the extruders 4 and 33, those having a short shaft in which the ratio L / D of the screw shaft is 4 to 10, and further 4 to 8 can be adopted. In addition, it is preferable that the kneaded body G0 is charged into the third rubber extruder 33 in such a manner that the respective extruders 5 and 33 are not directly connected, and are naturally dropped through or not via the transport conveyor 32. The kneaded body G0 from the third rubber extruder 33 can also be in a strip state or a pellet state.

  Note that a biaxial taper screw type similar to the second rubber extruder 5 may be employed as the third rubber extruder 33 as required. In particular, when forming a kneaded body with a high chemical compounding ratio, forming a higher quality kneaded body, or forming a kneaded body with a low chemical compounding ratio, the second rubber extruder 5 The first and second rubber extruders 4 and 5 can be sequentially connected to the downstream side.

  Next, as the rubber supply means 2, as described above, the strip Gs is cut in units of a reference length, and supplied to the first rubber extruder 4 intermittently in a fixed amount in units of the cut pieces. it can. In such a case, a cutting means for cutting the strip Gs by a reference length unit and a side length meter for determining the cutting length, such as a rotary encoder, are provided. The measuring means 8 measures the weight of one piece.

  When a cut piece is used, the cut piece previously introduced into the hopper of the first rubber extruder 4 in order to securely set the cut piece and a fixed amount of chemical from the chemical supply means 3. It is preferable to transfer the next cut piece and the chemical after the chemical and the chemical are transferred into the cylinder 21 and disappear from the hopper. The length of the cut piece is preferably in the range of 100 mm to 1000 mm.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

It is a side view which shows one Example of the manufacturing apparatus for enforcing the manufacturing method of the kneaded body of this invention. (A), (B) is the top view explaining the principal part of a 2nd rubber extruder, and sectional drawing. It is a side view which shows the other Example of a manufacturing apparatus. It is a side view which shows the further another Example of a manufacturing apparatus.

2 Rubber supply means 3 Chemical supply means 4 First rubber extruder 5 Second rubber extruder 31 Tapered screw shaft G Rubber G0 Kneaded body G1 Primary kneaded rubber C Chemical

Claims (2)

A kneaded body manufacturing method for manufacturing a kneaded body of rubber and chemicals,
The rubber sent quantitatively from the rubber supply means and the chemical sent quantitatively from the chemical supply means are simultaneously put into a single screw type first rubber extruder and kneaded to form the first kneaded rubber as the first kneaded rubber. A primary kneading step continuously extruded from a rubber extruder;
The primary kneaded rubber is put into a biaxial taper screw type second rubber extruder, and further includes a secondary kneading step of further kneading the primary kneaded rubber and extruding a kneaded body from the second rubber extruder. With
In the second rubber extruder, the helical pitch P of the taper screw shaft is 1.1 to 1.5 times the diameter d on the large diameter side of the taper screw shaft. Method. A kneaded body manufacturing apparatus for manufacturing a kneaded body of rubber and chemicals,
Rubber supply means for quantitatively supplying the rubber;
A medicine supply means for quantitatively supplying the medicine;
The rubber supply means, the rubber supplied simultaneously from the chemical supply means, the first rubber extruder of the single screw type, which kneads the chemical and continuously extrudes it as the primary kneaded rubber;
And further comprising a biaxial taper screw type second rubber extruder for further kneading the primary kneaded rubber and extruding the kneaded body,
In the second rubber extruder, the helical pitch P of the taper screw shaft is 1.1 to 1.5 times the diameter d on the large diameter side of the taper screw shaft. apparatus.

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