JPH06210635A - Supplying method for raw rubber - Google Patents

Abstract

PURPOSE:To automatically supply raw rubber to a compounding device. CONSTITUTION:Raw rubber with an average particle size of 5cm or less is supplied to a grinder along with a flocculation inhibitor and the obtained raw rubber powder of which the 30-mesh passing amt. is 80wt.% or more is supplied to a compounding device using a weighing device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a method for supplying raw rubber which can be used in the rubber manufacturing industry and the rubber processing industry.

[0002]

2. Description of the Related Art Conventionally, when obtaining a rubber product, raw rubber, filler, rubber chemicals and the like are kneaded with a Banbury mixer or a kneader to form a compound, which is molded by various means and then heat-treated. Vulcanization was performed, and then the molded product was deburred to obtain a product.

[0003]

By the way, from the past,
Raw rubber is generally supplied as a sheet-shaped material called a sheet or a veil or a solid material having a rectangular parallelepiped shape. Therefore, when the solid raw rubber is charged into a so-called compounding device such as a Banbury mixer or a kneader, it is necessary to cut and measure the lump of raw rubber in order to match the amount of the solid input with the set weight. there were. It is difficult to automate (unmanned) this process because it is time-consuming and dangerous to accurately cut the raw rubber to a desired weight.

Since fillers, rubber chemicals and the like are generally supplied in the form of powder or pellets, it is easy to automate these supply devices. Therefore, it is the current situation that only the raw rubber supply device remains difficult to automate.

On the other hand, from a long time ago, attempts have been made to produce and utilize powdered raw rubber in an attempt to rationalize the rubber processing step. For example, from the idea of shortening the kneading work time by a kneader or a roll by using powder rubber, or the idea of shortening the processing time when dissolving or swelling raw rubber in a solvent or the like. From the above, or from the idea that it is desired to have a more microscopic mixture when an alloy is produced by mixing and extruding with a resin or the like using an extruder, or powder rubber when molding using a rubber injection molding machine. There have been many attempts, including the expectation that a significant rationalization can be achieved by using.

Grinding of raw rubber is one of the very technically difficult things, and it is well known that it can be ground to about 20 mesh at room temperature by a machine of the type called a jet grinder. Among the pulverizers belonging to this type, the turbo mill type pulverizer can pulverize with the smallest particle size at room temperature, and when pulverizing raw rubber while supplying the anti-adhesion agent like the pulverizer used in the present invention, it passes 30 mesh. It is also possible for the amount to be greater than 80 weight percent. However, in the turbo mill type crusher, a large amount of heat is generated during crushing, which causes a temperature rise of 50 to 100 ° C. even when air is flowing, and the amount of energy (electric power) consumed is large. Even if the crusher itself is water-cooled, the discharged fluid is 40 to 60
There is also a disadvantage that the physical properties of the powdered raw rubber obtained tend to differ from those of the feed because of the temperature rise of ℃. On the other hand, when crushed at room temperature using an ordinary jet crusher, the crushing level reaches about 20 mesh as described above. In the prior art, this method has been regarded as the most economical, and powder rubber of around 20 mesh is used especially for the purpose of using a dissolving step in a solvent and for the purpose of manufacturing a resin compound by mixing and extruding with a resin or the like. Has been done.
However, even in the field of use of the above rubber powder, there is a demand for an economical method for producing raw rubber having a smaller particle size, because the post-process can be rationalized if the powder can be finely pulverized and the performance of the final product can be expected to improve.

If powdered rubber, a filler and a rubber drug are mixed in a mixer to form a compound in which powders are mixed and the compound can be directly applied to a rubber injection molding machine to obtain a rubber product, it is compared with a normal working process. It is possible to achieve a large rationalization. However, the particle size of raw rubber is 2
If it is about 0 mesh, a good rubber product cannot be molded. The reason is that the rubber particle size is large, and sufficient dispersion cannot be achieved only by kneading in the injection molding machine.

[0008] There have also been attempts to make powder rubber compounds usable by, for example, lengthening the kneading time required for kneading in a rubber injection molding machine, but it is necessary to drastically change the mechanical structure. It was suspended for economic reasons.

At present, the rubber injection molding machine is already widely used as a raw material for a compound obtained by kneading in advance in a Banbury mixer, a kneader or the like.

Therefore, it has been expected that if raw rubber can be pulverized to about 100 mesh, it will be widely used in many fields mentioned above.

It is not impossible to crush raw rubber to about 100 mesh, and there is freeze pulverization as a method for doing so. This method utilizes the fact that if the raw rubber is cooled to a glass transition temperature Tg or lower, the altitude is remarkably increased, so that the pulverization is easy.
The pulverization itself is possible if the pulverizer is also cooled in a low temperature environment such as 00 ° C.

However, in this case, it has no meaning economically. That is, the crushing itself generates heat, which greatly expands the cooling cost. Moreover, if the seal with the surrounding environment is not perfect, the moisture in the atmosphere will be absorbed, and a large amount of moisture will be adsorbed to the obtained rubber powder, and even if pulverization is performed while adding various additives, the particles will be separated from each other. Aggregate.

The present invention has been made in view of the above circumstances, and it is possible to automate the supply of raw rubber, and
It is an object of the present invention to provide a raw rubber supply method which can be rationalized in other various operations and can provide a simplified manufacturing method of a raw material compound for a rubber injection molding machine.

[0014]

In order to achieve the above object, the present invention supplies raw rubber having an average diameter of 5 cm or less to a pulverizer as described below together with an anti-agglomeration agent to obtain most of the raw materials.
The content of the raw rubber powder is smaller than 0 mesh, and the obtained rubber powder is supplied to the compounding device using a measuring device.

[0015]

[Function] If the raw rubber is made into fine powder as described above, the raw rubber manufacturer supplies the user with the powder rubber, and
The user can store this in the tank or hopper and use it automatically for weighing. In addition, since it is possible to use tank trucks and flexible containers for transporting raw rubber,
It can also streamline transportation.

When the raw rubber is made into fine powder as in the present invention, the raw rubber is put into a solution and dissolved to form a rubber liquid,
Adhesives, rubber-based packing materials, rubber-based sealing materials, etc. can be finally manufactured, and in these fields, the measuring process and the melting process can be greatly rationalized.

In the present invention, raw rubber can be made into a fine powder,
In a rubber compound kneading process using a kneader, it is possible to greatly reduce the weighing and kneading time. In the present invention, the raw rubber fine powder may be weighed and blended with other chemicals and used as it is, or the raw rubber fine powder finely adjusted with the raw rubber fine powder of the present invention to obtain a compound. You can also ding.

Further, in the present invention, since raw rubber can be made into fine powder, it is weighed and then mixed with a filler and a rubber drug in a Henschel mixer or the like to form a compound, which is directly fed to a rubber injection molding machine. As a raw material,
It is possible to manufacture products of the same quality as conventional products, and in this case, it is possible to greatly rationalize equipment and work.

The operation of the present invention will be described in more detail.
It is as follows. The raw rubber to which the present invention is applied,
At room temperature, it is generally very sticky and
Any raw rubber that easily causes cold flow, such as BR, can be used. That is, NR, SBR, BR, I
Rubbers such as R, IIR, NBR, CR, EPR, acrylic rubber, silicone rubber and fluorine rubber, or oil-extended rubbers or mixtures thereof can be used.

Regarding the form of these rubbers when they are fed to the crusher, it is usually preferable that they are in the form of flakes or particles or lumps having a diameter of 5 cm or less. Usually, in the production of synthetic rubber, a flake-shaped step is often performed, and in that case, the flake-shaped rubber can be used as it is.

On the other hand, it is preferable to use a coarsely crushed product, more preferably 2-3 cm, in order to obtain a product having a diameter of 5 cm or less.
It is recommended to crush it to a small size before supplying.

Air is usually blown to the crusher by a blower. At the exit of the crusher, two cyclone type classifiers are usually arranged in series. Large particle size products are collected by the front cyclone, small particle size products are collected by the rear cyclone, and gas that has passed through both cyclones is collected. Is preferably purified by a bag filter and discharged or circulated.

In this case, when flakes of crude rubber or coarsely crushed products are added, powder rubbers having different particle diameters can be obtained from the two cyclones. The air flow rate and the feed rate are adjusted so that the powder rubber having the target particle size can be obtained in the maximum ratio in the subsequent cyclone. Then, the coarsely crushed product obtained by the previous cyclone is appropriately recycled to the inlet.

According to the crusher used in the present invention, it is possible to easily crush a finer than 30 mesh at a rate of 80% or more in one pass without adjusting the machine.
When targeting -100 mesh, it is necessary to finely adjust the gap between the crushing section and the casing. In addition, it becomes necessary to adjust the addition ratio of the coagulation inhibitor to be described later.

As the anti-agglomeration agent, the role is to coat the surface of the rubber powder to prevent the rubber powder from adhering to each other, so that any substance that is not self-adhesive can be used.

However, the coagulation inhibitor is preferably a filler or the like finally contained in the rubber compound. For example, powders of calcium carbonate, magnesium carbonate, clay, talc, silica, metal stearate, carbon black, or the like can be used as the anticoagulant.

The anticoagulant is required in a sufficient amount to prevent the adhesion of the rubber powder, and the amount greatly changes under various conditions. Since it is generally difficult to determine the supply amount of the anti-aggregation agent, a method of facilitating this is to supply a large amount of the anti-aggregation agent that can also be used as a filler.
For example, the amount of rubber is preferably 1 to 35% by weight, more preferably 5 to 30% by weight, still more preferably 10 to 25% by weight.

When a large amount of the anticoagulant is supplied in this manner, the anticoagulant is separated by using an air separator composed of several stages, that is, either a cyclone or a bag filter, and this is recycled. Just do it.

If the raw material raw rubber, air and the coagulation inhibitor are supplied and the operating condition of the crusher is stabilized, the composition of the recovered rubber powder is also stabilized. The rubber powder having a stable composition as described above can be sufficiently used as an intermediate raw material by measuring the amount of raw rubber and the amount of filler contained in the rubber powder.

The powder rubber obtained as described above can be stored in a hopper or the like. Therefore, tank cars,
It can also be transported in flexible containers.

After transportation, it can be transferred to a hopper or the like again, and can be supplied to the compounding device by using an ordinary measuring device for treating powder and an automatic measuring and feeding device.

Further, it is necessary to provide an air outlet in the hopper to prevent blocking of the rubber powder in the hopper, or to install a water cooling device in the hopper to prevent the temperature rise of the rubber powder in the summer. However, even if these devices are provided, it is possible to reduce the manual labor by automatic weighing to the compounding device, at least.

[0033]

【Example】

(Example-1) Using an ultra rotor type crusher model III A type manufactured by Altemburger, NBR (trade name JSR N240S, Mooney viscosity 100 ° C 63, bound acrylonitrile 20%) flakes before veil forming Was crushed.

As shown in FIGS. 1 and 2, the crusher has an inlet (2) through which gas and raw materials pass, a rotary blade (4) attached to a vertical rotary shaft (3). A crushing section (5), a casing (1) forming a narrow gap with the crushing section, and a discharge section (7) for discharging gas and crushed material,
And a rotator plate (8), and the crushing section (5) forms a chamber-like empty chamber (6) along the outer circumference. Each room (6)
As shown in FIG. 2 and FIG. 3, the partition plate has an adjusting plate (9).
Is attached, and each adjustment plate (9) can be moved in the radial direction to adjust the gap with the casing (1). The adjusting plate 9 is not shown in FIG. 1 because the drawing becomes complicated.

Here, the crushing section (5) and the casing (1)
Set the gap between and to be 2 mm, and rotate at 2500
Adjust between ~ 3000 rpm, adjust the air flow appropriately,
150 kg / hr of the above flake rubber from the raw material charging port
Then, the light calcium carbonate filler was added at 15 kg / hr.

The charged raw material is repelled upward by the rotary plate (8), crushed by the rotary blade (4), and is carried by the air flow into the crushing unit (5) between the casing (1) and the casing (1). To do. With the rotation of the crushing section (5),
The jet airflow S is generated in the space (6) and in the space surrounded by the casing (1), the inflowing raw materials collide with each other, rise while being crushed, and are discharged from the discharge part (7) together with the gas. It

When the crushed product was collected by two cyclones and a bag filter connected to the outlet of the crusher, a 25 kg / hr coarse crushed product (10-40 mesh) was obtained from the previous cyclone, and From the cyclone, 135 kg / hr of powdered rubber (60 to 100 mesh) was obtained. This powder rubber contained 9.6 wt% filler. The powdered NBR rubber was weighed, and a powdered rubber compound was prepared according to the formulation shown in Table 1.

[0038]

[Table 1]

That is, all of the compounding ratios were put into a Henschel mixer, the blade speed was gradually increased to 3000 rpm.
And the stirring was completed after 4 minutes.

Using the rubber injection molding machine manufactured by Morikawa Seisakusho, the powder rubber compound was molded into dumbbell No. 3 shaped pieces under the molding conditions shown in Table 2. The results of measuring the physical properties are shown in Table 3. This result shows that a product almost equivalent to the conventional method of Reference Example-1 can be produced.

[0041]

[Table 2]

[0042]

[Table 3]

Reference Example-1 A kneaded product was obtained by the roll kneading method using bale rubber at the compounding ratio shown in Table 4.
Using this as a raw material, a dumbbell No. 3 piece was molded by an ordinary press molding method. The press conditions were 170 ° C. and 4 minutes. The evaluation results are shown in Table 3.

[0044]

[Table 4]

Reference Example-2 A kneaded product was obtained by the roll kneading method at the compounding ratio shown in Table 5. This was used as a raw material, charged into the same injection molding machine as in Example-1, and molded and evaluated under the same conditions. The formulation is substantially the same as in Table 1. The evaluation results are shown in Table 3.

[0046]

[Table 5]

(Comparative Example-1) Conventionally, it was not impossible to pulverize the adhesive raw rubber, and it has been tested with many pulverizers and pulverization conditions. There are also examples of pulverization at an ultralow temperature such as -100 ° C. According to these, 40 to 50 mesh pulverization is possible, but it is expensive and practically meaningless.

The 20-mesh level is practically used in the conventional mechanical grinding method. NBR was pulverized by a jet pulverization type commercial machine in the same manner as in Example-1 to obtain NBR powder rubber (average mesh 25, containing 9.6% of light calcium carbonate filler) of 20 mesh pass.

This NBR rubber was mixed in a Henschel mixer using the same formulation as in Table 1 as in Example-1. The obtained compound was used and injection-molded in the same manner as in Example-1 to evaluate the obtained molded product. The results are shown in Table 3.

Now, the relationship between Example-1, Reference Examples-1 and 2, and Comparative Example-1 will be summarized with reference to Table 3. First, Reference Examples 1 and 2 are molding processing methods that are currently generally performed. In each case, there is a kneading step with a kneader or a Banbury mixer, and the consumption time is long, but particularly in Reference Example-1 using a press machine, the consumption time is the longest. On the other hand, in Example-1, since only mixing was performed to form the compound, the total consumption time was remarkably shorter than that of Reference Example-2.

In the product evaluation of Example-1, the tensile strength is slightly worse than that of Reference Examples-1 and 2. However, considering the reduction in time, it can be said that there is sufficient merit. If the physical properties required for the product are not at the last level, Example-1
Can be used as a product evaluation with substantially no difference from Reference Examples-1 and 2.

On the other hand, Comparative Example-1 and Example-1 consume the same time in both steps. However, their physical properties are very different. This difference is mostly due to the small particle size of the raw rubber powder, and partly due to the fact that Example-1
It is considered that this is due to the fact that there is no heat alteration at all because of the fact that almost no heat generation is observed.

In the case of direct rubber injection molding using a powdered rubber compound, the smaller the particle size of the powdered rubber is, the more preferable the product evaluation is. When the system according to the present invention is used, the particle size is markedly smaller than that of the conventional ground product. Since raw rubber powder having a diameter that is not thermally altered can be obtained, it is possible to open the way to a new method of using powdered rubber.

In order to make Example-1 more understandable,
A process comparison is shown in FIG. The image of the length of the process time is shown by the lengths of the vertical arrows a, b, and c, but the system using the powder rubber of the present invention consumes less overall time and does not require manpower, so it is fully automated. Is also possible.

(Example-2) Using an ultra rotor type crusher Model III A type manufactured by Altenburger S,
BR (product name JSR 1712) BR (product name JS
R BR01) was ground as follows.

In this embodiment, the gap between the crushing section and the casing is set to be 2 mm, and the rotation speed is 2500 to 30.
Adjusted between 00 rpm and the air flow rate, 150 kg / hr of flakes of SBR (product name JSR1712) (the product before being compressed into a veil at the factory) and HAF black (product First name N-
330) was charged at 16.5 kg / hr.

When the crushed product was collected by two cyclones and a bag filter connected to the outlet of the crusher, about 10 to 20 mesh product was obtained from the previous cyclone at about 31 kg / hr, and from the subsequent cyclone. 60
About 100 mesh product was obtained at about 131 kg / hr.

When the rubber powder obtained from the subsequent cyclone was analyzed, the filler was contained in an amount of 9.1 wt%. BR (brand name JSR BR0
When 1) was crushed from flakes, a 60 to 100 mesh product was obtained, and the filler content was 9.5 wt%. It was clear that both rubber powders had no adhesive property at all and could be handled like sand.

For a passenger car tire tread, a kneading process was carried out using a No. 9 Banbury mixer (capacity: 200 liters) with the following composition. SBR (Brand name JSR 1712) 64.20 kg BR (Brand name JSR BR01) 20.00 kg Zinc oxide (# 3) 2.00 kg Stearic acid 1.33 kg HAF black (Brand name N-330) 56.67 kg Intermediate oil ( Brand name JSR AROMA) 13.33 kg Anti-aging agent (brand name IPPD) 0.67 kg Vulcanization accelerator (brand name OBS) 0.80 kg Sulfur 1.00 kg

When charging these raw materials, the SBR was one 35 kg bale and the SBR obtained in the previous step.
32.123 kg of powdered rubber was used, and 22.100 kg of BR powdered rubber obtained in the previous step was also used for BR. Also,
HAF black was used by subtracting the amount contained in the rubber powder from the above table and using 51.647 kg.

It was found that the raw material supply to the Banbury mixer can be completely automated and unmanned by charging these powdered rubbers using an automatic powder metering feeder and charging the bale rubbers using an automatic charging device. . In addition, the properties of the final product using the obtained rubbery rubber were completely the same as those of the conventional operation.

[0062]

According to the method for feeding raw rubber of the present invention, the raw rubber powder obtained by feeding flaky raw rubber or raw rubber roughly crushed to a major axis of 5 cm or less to a pulverization system together with an anti-agglomeration agent (filler) is obtained. Is fed to the compounding device (mixer) using a weighing device, so that the raw rubber can be easily weighed and a desired amount of raw rubber can be quickly fed to the compounding device (mixer). Weighing can be automated, and if a computer is used, it can be completely automated.

Therefore, when supplying raw rubber to the compounding device, it is necessary to cut the rubber veil and finely measure and integrate, so that it is troublesome to supply the compounding device to the compounding device. And the supply work will be more efficient and rationalized.

Conventionally, it was dangerous to use a large cutting machine or a kitchen knife for cutting work, whereas the present invention eliminates the need for such a cutting machine. Therefore, these dangerous works can be eliminated.

Further, the raw rubber which can be fed by the raw rubber feeding method according to the present invention has a particle size smaller than that of any raw rubber powder conventionally known and used in the industry. Is big. In particular, since it is not possible to find an element that makes the crushing process cost higher than the conventional crushing cost, there are great practical advantages.

[Brief description of drawings]

FIG. 1 is a perspective view conceptually showing a crusher adopted in a raw rubber supply method according to the present invention.

FIG. 2 is a plan view conceptually showing a crusher adopted in the raw rubber supply method according to the present invention.

FIG. 3 is a plan view conceptually showing a crushing state of a crusher adopted in the raw rubber supplying method according to the present invention.

FIG. 4 is a block diagram conceptually showing a crushing system in the raw rubber supply method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Entrance part 3 Rotating shaft 4 Rotating blade 5 Grinding part 6 Vacancy 7 Discharge part 8 Rotating plate 9 Adjusting plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Maruyama 4-6-5 Higashiueno, Taito-ku, Tokyo Yamashonai Co., Ltd.

Claims (7)

[Claims] 1. A raw rubber having an average diameter of 5 cm or less is supplied to a pulverizer together with an agglomerating agent, and the obtained raw rubber powder having a 30-mesh passing amount of 80% by weight or more is supplied to a compounding device using a measuring device. A method for supplying raw rubber characterized by: 2. The crusher comprises a casing (1), an inlet (2) provided in the casing for supplying gas and raw materials, and a rotary blade (4) supported by a vertical rotary shaft (3). And a crushing section (5), and the crushing section (5) has a small chamber-like empty chamber (6) along the outer circumference, and the crushing section (5) has a predetermined gap with the casing (4). It is placed without any further
The casing (1) is provided with a discharge part (7) for discharging the gas and the crushed material, wherein the discharge part (7) is provided.
The method for supplying raw rubber according to. 3. The casing (1) comprises the crushing section (5).
The method for supplying raw rubber according to claim 1, further comprising means for adjusting a gap between the raw rubber and the raw rubber. 4. The method for supplying raw rubber according to claim 1, wherein the aggregation preventing agent is an inorganic or organic filler used as a rubber filler. 5. A component other than the gas of the fluid discharged from the crusher is separated into at least two components by using a separator, and one component has a 30 mesh passage amount of 80% by weight or less and is insufficiently pulverized. Let the ingredients gather,
The method for supplying raw rubber according to claim 1, wherein the raw rubber is recycled to the inlet of the crusher. 6. A component other than the gas of the fluid discharged from the pulverizer is separated into at least two components by using a separator, and one component is made to collect an agglomeration inhibitor not adhered to the raw rubber powder. The raw rubber supply method according to claim 1, wherein the raw rubber is recycled to the inlet of the crusher. 7. The method for supplying raw rubber according to claim 1, wherein the raw rubber powder obtained from the separator system according to claim 5 is supplied to the compounding device by using an automatic powder measuring device.