JP6554802B2 - Kneading apparatus and kneading method - Google Patents

Description

  The present invention relates to a kneading apparatus including a kneader and a predetermined strainer, and a kneading method using the kneading apparatus.

  Natural rubber is used in large quantities in each rubber industry in view of its excellent physical properties, availability (inexpensive), and environmental issues. Natural rubber has a larger molecular weight than ordinary synthetic rubber and is inferior in processability. Therefore, natural rubber is kneaded with a small amount of peptizer, and the molecular weight of the raw rubber is moderately lowered to improve processability. A process, a method of performing a kneading process of adding a compounding agent such as a reinforcing agent and a softening agent after kneading after removing a foreign substance contained in natural rubber using a mesh-like member, is known. It has been.

  However, natural rubber produced by conventional methods has a specific odor, and there is a problem that natural rubber is used as a raw material and gives off a specific odor in the process of manufacturing rubber products. There is a problem of giving off a specific odor. Therefore, in order to solve these problems, there is a demand for natural rubber with a reduced specific odor.

  Various techniques have been proposed as a method for reducing the odor of natural rubber. For example, Patent Documents 1 to 3 describe a tire rubber composition having a sustained fragrance by adding a fragrance such as a terpene compound during rubber kneading, but these mask the odor of vulcanized rubber. Therefore, it is not a method for reducing the natural rubber odor, and the odor reduction effect is not sufficient.

  Further, Patent Document 4 describes that, by using a deproteinized natural rubber, color turbidity and rubber odor can be eliminated as much as possible, but deproteinization processing takes time and the odor reduction effect is not sufficient. .

JP 2007-8225 A JP 2012-255066 A JP 2007-51265 A Japanese Patent No. 3806317

  It is an object of the present invention to provide a kneading apparatus and a kneading method that can remove the characteristic odor of natural rubber.

  The inventor has found that the odor peculiar to natural rubber is reduced by subjecting the kneaded material discharged from the kneading machine to a strainer treatment using a strainer equipped with a deaeration means, and has completed the present invention. It was.

  That is, the present invention relates to a kneading apparatus having a kneader and a strainer provided with a deaeration means.

  It is preferable that the strainer is a strainer further provided with water supply means.

  Furthermore, the present invention relates to a method for kneading a rubber composition including a mastication step for natural rubber by the kneading apparatus.

  According to the kneading apparatus and the kneading apparatus having the strainer provided with the deaeration means of the present invention and the kneading method for kneading natural rubber by the kneading apparatus, the characteristic odor of natural rubber can be reduced easily and effectively. A kneading apparatus and a kneading method can be provided.

It is the schematic of the kneading apparatus which is one Embodiment of this invention.

  Hereinafter, the kneading apparatus and the kneading method of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to this embodiment. FIG. 1 shows a kneading apparatus having a kneading machine 1, an extruder 2, a strainer 3 and an extrusion head 4 as one embodiment of the present invention. In addition, the extruder 2, the strainer 3, and the extrusion head 4 are shown with sectional drawing.

  As shown in FIG. 1, the kneading apparatus of the present embodiment includes a kneading machine 1, a charging port 21 into which the kneaded material R1 discharged from the kneading machine 1 is charged, and an extrusion screw 22 that pushes out the charged kneading material R1. This is a kneading apparatus having an extruder 2, a mesh member 31 inside, a strainer 3 provided with a deaeration means 32 and a water supply means 33, and an extrusion head 4 serving as a discharge hole.

  The kneader 1 is not particularly limited, and a kneader conventionally used for manufacturing rubber products such as a Banbury mixer and an open roll can be used. Among these, a Banbury mixer is preferable because of its excellent productivity.

  The kneaded material discharged from the kneader 1 may be supplied to the strainer 3 by the extruder 2 as shown in FIG. 1, or may be supplied by other methods instead of the extruder. For the reason that the kneaded material can efficiently pass through the mesh-like member 31 in the strainer by the extrusion pressure by the extrusion screw 22, it is preferable to supply the strainer by the extruder. As shown in FIG. 2 and the strainer 3 are more preferably connected. Even if it is another method, as long as the kneaded material R1 can be passed through the mesh member 31 in the strainer, the kneaded material may be supplied to the strainer by another method.

  The extruder in the case of providing the extruder 2 is not specifically limited, The extruder conventionally used for manufacture of a rubber product etc. can be used. For example, an extruder equipped with an inlet for charging the kneaded material and an extrusion screw for extruding the charged kneaded material as shown in FIG.

  The strainer 3 has a mesh-like member 31 disposed therein, and all of the kneaded material conveyed into the strainer 3 passes through the mesh of the mesh-like member 31, so that the dust contained in the kneaded material, etc. Unnecessary material can be removed (strainer treatment). The strainer according to the present invention is provided with a deaeration means 32. By degassing the inside of the strainer 3 by the deaeration means 32, the odor peculiar to natural rubber can be reduced, and further, the passage in the strainer process is performed. Performance can be improved and the required time can be shortened.

  The deaeration means 32 can be a device comprising a vacuum pump and a trap, and the inside of the strainer 3 is connected to the trap and the vacuum pump. By operating the vacuum pump, the air in the strainer 3 is deaerated. The odor peculiar to natural rubber can be reduced. Here, the trap is a cylindrical device connected downstream of the vacuum pump, and is a facility that aggregates and captures foreign matters such as water sucked by the vacuum pump by cooling with liquid nitrogen or the like. By providing the trap, it is possible to prevent a decrease in the deaeration speed due to foreign matter mixing in the vacuum pump.

  The connection location of the deaeration means 32 in the strainer 3 is downstream of the mesh member 31 (the reverse side of the kneader and the extruder with respect to the mesh member 31). This is preferable because the passage can be assisted by a suction force, the passage in the strainer process can be improved, and the required time can be shortened.

  The degassing speed inside the strainer 3 by the degassing means 32 is that the volatile odor components peculiar to natural rubber can be sufficiently degassed, and that water can be sufficiently degassed (suctioned) when water is supplied. For the reason, 8.5 L / min or more is preferable, and 10 L / min or more is more preferable.

  As shown in FIG. 1, the strainer 3 preferably further includes water supply means 33. By supplying a liquid such as water from the water supply means 33 to the kneaded material in the strainer 3, the odor component peculiar to natural rubber is dissolved in water, and the deaeration means 32 sucks the odor component together with water. The odor peculiar to natural rubber can be further reduced. In addition, the connection part of the water supply means 33 in the strainer 3 is upstream of the mesh member 31 (the kneader and the extruder are on the same side with respect to the mesh member 31), so that the natural rubber can be efficiently used. It is preferable because it can reduce the odor.

  Examples of the liquid supplied from the water supply means 33 include water such as pure water, distilled water, tap water, and well water, and pure water is preferable because it does not cause natural rubber alteration or contamination. .

  The amount of liquid supplied by the water supply means 33 is preferably 0.5 g or more, more preferably 1.0 g or more with respect to 1 kg of natural rubber, for the purpose of exhibiting a sufficient odor reduction effect. Moreover, since there exists a possibility that it may not be able to attract | suck and remain | survive when there is too much supply amount, 50 g or less is preferable with respect to 1 kg of natural rubber, and 40 g or less is more preferable.

  It is preferable that an extrusion head 4 for forming the kneaded material into a sheet-like rubber sheet R2 is provided downstream of the strainer 3. By forming the sheet-like rubber sheet R2, the handling in the subsequent kneading step becomes easy. Note that a roller head or the like may be provided instead of the extrusion head 4.

  The kneading method of the present invention is a kneading method using the kneader. That is, the kneaded material R1 kneaded by the kneader 1 is supplied to the strainer 3 by the extruder 2 and subjected to the strainer treatment, and further molded into the rubber sheet R2 by the extrusion head 4. Moreover, it can be set as the kneading | mixing method including the mastication method of the natural rubber of this invention. That is, a kneading method of a rubber composition comprising a kneading step of kneading natural rubber with the kneading apparatus and kneading the natural rubber after mastication with other rubber components and additives, and kneading of the present invention This is a kneading method in which by using natural rubber that has been masticated by an apparatus, a kneading step with reduced odor peculiar to natural rubber is obtained, and a rubber composition with further reduced odor is obtained.

  As said natural rubber, what is common in rubber industry, such as SIR20, RSS # 3, TSR20, can be used. In the natural rubber mastication step, a kneading accelerator common in the rubber industry may be blended. In addition, a filler having low dispersibility such as carbon black or silica may be added in the mastication step because the dispersibility in the rubber component is improved.

  Other rubber components include isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile butadiene. Synthetic rubber such as rubber (NBR) may be mentioned, and may be appropriately selected depending on the purpose of use of the rubber product.

  Additives include various reinforcing agents, softeners, zinc oxide, various anti-aging agents, anti-ozone degradation agents, coupling agents, vulcanizing agents such as waxes, sulfur or sulfur compounds, and vulcanization accelerators in the rubber industry. What is necessary is just to select suitably the compounding agent generally used according to the use purpose etc. of a rubber product.

  The rubber composition produced through the kneading method of the present invention can be used for each member of a tire because a rubber composition with reduced natural odor is obtained.

  The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Hereinafter, various chemicals used in Examples and Comparative Examples will be described together.
Natural rubber: TSR20
Carbon Black: Show Black N220 (N2SA: 111 m ² / g) manufactured by Cabot Japan

Examples and Comparative Examples 10 kg of natural rubber and 2 kg of carbon black were masticated with a 16 L Banbury mixer, and a strainer treatment with a strainer directly connected to the discharge part was performed under the conditions shown in Table 1. The following evaluation was performed with respect to the obtained kneaded material (kneaded material).

<Odor evaluation>
Ten panelists evaluated the odor of the kneaded material 60 minutes after the end of the mastication process according to the following criteria. The most frequently evaluated results are shown in Table 1.
◎ No odor ○ Slight odor × Odor

<Strainer passability>
The time required for the strainer treatment was measured, and the passing speed was calculated. A result is shown by the index | exponent which sets the comparative example 1 to 100 by the following formula. The higher the index, the shorter the time taken for the strainer treatment.
(Passability index) = (Passing speed of each Example) / (Passing speed of Comparative Example 1) × 100

  From the results shown in Table 1, it can be seen that the kneading apparatus and the kneading method of the present invention are a kneading apparatus and a kneading method that can easily and effectively reduce the characteristic odor of natural rubber.

DESCRIPTION OF SYMBOLS 1 Kneading machine 2 Extruder 21 Input port 22 Extrusion screw 3 Strainer 31 Mesh-like member 32 Deaeration means 33 Water supply means 4 Extrusion head R1 Kneaded material R2 Rubber sheet

Claims (4)

Kneader, a kneading apparatus having mesh member for passing a kneaded material containing a natural rubber, degasser, and a strainer having an extrusion head or roller head for molding the kneaded mixture into a sheet. The kneading apparatus according to claim 1, wherein the strainer is a strainer further provided with water supply means. The kneading apparatus according to claim 1 or 2 , wherein the deaeration means is connected downstream of the mesh member. A method for kneading natural rubber with a kneading machine having a kneader, a mesh-like member for allowing a kneaded material containing natural rubber to pass through, and a strainer provided with a deaeration means .

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