JP2018030286A - Rubber material kneading method and apparatus - Google Patents

Abstract

A rubber material kneading method and apparatus capable of obtaining a rubber material with stable quality while suppressing an excessive temperature rise in a kneading chamber of a closed kneader. A cooling medium C is introduced into a kneading chamber 4a by a refrigerant charging mechanism 14 to lower the temperature in the kneading chamber 4a. Then, the cooling medium C contains the amount of water generated in the kneading chamber 4a. The water content adjusting mechanism 15 reduces the water content of at least one non-vulcanizing compounding agent N1 in advance, and a part of the non-vulcanizing compounding agent N2 including the non-vulcanizing compounding agent N1 thus adjusted is reduced. Prior to charging into the kneading chamber 4a and stirring by rotating the rotor 3, the raw rubber G and the remaining non-vulcanized compounding agent N3 are then charged into the kneading chamber 4a and the rotor 3 is rotated. Thus, the rubber material R is kneaded while maintaining a predetermined temperature range. [Selection] Figure 3

Description

  The present invention relates to a rubber material kneading method and apparatus, and more particularly, a rubber material kneading method capable of obtaining a rubber material with stable quality while suppressing an excessive temperature rise in a kneading chamber of a closed kneader, and It relates to the device.

  For the tire tread rubber and the like, the rolling resistance and wet grip performance of the tire can be improved by using silica-containing rubber. In the kneading step of the silica-blended rubber, in order to improve the dispersibility of the silica, a coupling agent is blended and kneaded by a coupling reaction with silica. Due to the coupling reaction heat or the like, a large amount of heat storage occurs in the closed kneader that is kneading.

  When multiple batches of silica compounded rubber are kneaded continuously using a closed-type kneader, the heat storage cannot be sufficiently removed in the interval between batches, and the temperature in the kneading chamber (casing inner wall surface, rotor, etc.) rises excessively. To do. Not only silica-blended rubber but also rubber material must be kneaded in a predetermined temperature range, and the temperature rises when the rotor is rotated and kneaded. Therefore, when the temperature in the kneading chamber is excessively increased, the rotor cannot be sufficiently rotated and kneaded, and there is a problem that the rubber quality is affected. For rubber materials other than silica-blended rubber, when the temperature in the kneading chamber rises excessively, the same problem arises because the rotor cannot be sufficiently rotated and kneaded.

  For example, a method has been proposed in which steam is supplied to a kneading chamber to knead unvulcanized rubber, silica, and a coupling agent (see Patent Document 1). In this kneading method, only a predetermined amount of water required for the reaction between silica and the coupling agent is supplied as steam (paragraph 0016), and it is not intended to reduce the temperature in the kneading chamber by steam. . Moreover, since only water vapor is not supplied to the kneading chamber first, the temperature in the kneading chamber cannot be sufficiently lowered by this water vapor.

JP 2006-123272 A

  An object of the present invention is to provide a rubber material kneading method and apparatus capable of obtaining a rubber material with stable quality while suppressing an excessive temperature rise in a kneading chamber of a closed kneader.

  The rubber material kneading method of the present invention for achieving the above object is a rubber material kneading method in which a rubber material comprising a raw rubber and a plurality of types of non-vulcanized compounding agents is kneaded with a closed kneader. A cooling medium is introduced into the kneading chamber of the closed kneader to lower the temperature in the kneading chamber, and then the water content is reduced and adjusted in advance according to the amount of water generated in the kneading chamber by the introduced cooling medium. A part of the non-vulcanizing compounding agent including the non-vulcanizing compounding agent of a kind is introduced into the kneading chamber in advance and stirred by rotating a rotor provided in the kneading chamber, The raw rubber and the remaining type of non-vulcanized compounding agent are put into the kneading chamber and the rotor is rotated to knead the rubber material while maintaining it in a predetermined temperature range. .

  The rubber material kneading apparatus of the present invention has a rotor provided in a kneading chamber, and the rubber material composed of raw rubber and a plurality of types of non-vulcanized compounding agents is rotated by rotating the rotor. In a rubber material kneading apparatus provided with a closed kneading machine for kneading in a kneading chamber, the refrigerant material charging mechanism for charging a cooling medium into the kneading chamber and a water content adjusting mechanism are provided, and the water content adjusting mechanism is charged into the kneading chamber In accordance with the amount of water generated in the kneading chamber by the cooling medium, the water content is adjusted in advance by the water content adjusting mechanism with respect to at least one of the non-vulcanized compounding agents, and the cooling medium is mixed with the kneading chamber. The temperature in the kneading chamber is lowered by being charged into the chamber, and then a part of the non-vulcanized compounding agent including the non-vulcanized compounding agent whose water content has been adjusted to be reduced in advance is preceded by the Put into the kneading chamber, Then, the rubber material is brought to a predetermined temperature range by feeding the raw rubber and the remaining types of non-vulcanizing compounding ingredients into the kneading chamber and rotating the rotor. It is characterized in that it is maintained and kneaded.

  According to the present invention, the temperature in the kneading chamber can be sufficiently lowered by introducing the cooling medium into the kneading chamber of the closed kneading machine in an empty state. In addition, the non-vulcanized compounding agent is prepared by rotating the rotor together with the cooling medium and stirring the non-vulcanizing compounding agent whose water content is reduced according to the amount of water generated in the kneading chamber by the introduced cooling medium. The agent can absorb moisture from the cooling medium. Therefore, the amount of water as the rubber material becomes appropriate, and it is possible to avoid the occurrence of excessive slip between the rubber material and the rotor. Accordingly, it becomes possible to obtain a rubber material with stable quality.

It is explanatory drawing which illustrates the kneading apparatus of the rubber material of this invention. It is explanatory drawing which illustrates the kneading | mixing chamber by AA sectional view of FIG. It is explanatory drawing which illustrates the state which supplied the cooling medium to the kneading | mixing chamber of FIG. FIG. 4 is an explanatory diagram illustrating a state where a part of the non-vulcanized compounding agent including a non-vulcanized compounding agent whose water content has been adjusted in advance after the state of FIG. 3 is put into the kneading chamber and stirred. . It is explanatory drawing which illustrates the state which knead | mixes the rubber material with the kneading apparatus after the state of FIG.

  Hereinafter, the rubber material kneading method and apparatus of the present invention will be described based on the embodiments shown in the drawings.

  A rubber material kneading apparatus 1 (hereinafter, referred to as a kneading apparatus 1) of the present invention illustrated in FIGS. 1 to 2 kneads an unvulcanized rubber material R. In this embodiment, the rubber material R is a silica-blended rubber composed of a raw rubber G and a plurality of types of non-vulcanized compounding agents N (N1, N2, N3) including silica N1 and a coupling agent N2. Thus, the non-vulcanized compounding agent N is uniformly dispersed in the raw rubber G to obtain an appropriate viscosity.

  As the raw rubber G, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), 1,2-polybutadiene, chloroprene rubber, butyl rubber, styrene-butadiene rubber (SBR), nitrile rubber (acrylonitrile rubber, Examples thereof include hydrogenated nitrile rubber) and ethylene propylene diene rubber. These are used individually by 1 type or in combination of 2 or more types.

  As the silica N1 and the coupling agent N2, well-known compounds blended in the rubber composition for uses such as tires can be used. As non-vulcanizing compounding agent N, in addition to silica N1 and coupling agent N2, as required, other non-vulcanizing compounding agents N3 include various fillers (for example, carbon black), zinc oxide, Stearic acid or the like is used. Depending on the rubber material R, the non-vulcanized compounding agent N may not contain the silica N1 and the coupling agent N2.

  The kneading apparatus 1 includes a hermetic kneader 2 such as a Banbury mixer having a rotor 3 in a kneading chamber 4a, a temperature sensor 11, a control unit 12 that controls the rotation of the rotor 3, and a cooling medium in the kneading chamber 4a. A refrigerant charging mechanism 14 for charging C and a water content adjusting mechanism 15 are provided.

  A ram chamber 4b is connected above the kneading chamber 4a. The kneading chamber 4a is provided with a pair of rotors 3 and an oil charging portion 5 that are arranged to face each other. Blades 3b are projected from the rotation shafts 3a of the respective rotors 3, and the rotation shafts 3a arranged in parallel are rotated by a driving motor. A discharge door 10 that opens and closes is provided on the bottom surface of the kneading chamber 4a.

  A circulation path through which cooling water flows is formed inside the casing forming the kneading chamber 4a and inside the rotating shaft 3a. By circulating cooling water through this circulation path, the inside of the kneading chamber 4a can be cooled.

  In the ram chamber 4b, a ram 8 that moves up and down to adjust the pressure (ram pressure) in the kneading chamber 4a is disposed. The ram chamber 4 b is further provided with a rubber charging unit 6 for charging the raw rubber G and a compounding agent charging unit 9 for charging the non-vulcanized compounding agent N from the hopper 7.

  The temperature sensor 11 is provided in the kneading chamber 4a with its tip portion exposed. The temperature sensor 11 sequentially detects the temperature of the rubber material R kneaded in the kneading chamber 4a. Data detected by the temperature sensor 11 is input to the control unit 12.

  The refrigerant charging mechanism 14 includes a storage tank 14a for the cooling medium C, a nozzle 14b, and a supply path 14c that connects the storage tank 14a and the nozzle 14b. The nozzle 14 b is connected to a hole formed in the kneading chamber 4 a as the refrigerant supply unit 13. Depending on the specifications of the nozzle 14b, the cooling medium C can be sprayed or dropped as well as simply being put into the kneading chamber 4a. The refrigerant supply unit 13 can be provided not only on the front and rear wall surfaces of the casing forming the kneading chamber 4a but also on a curved side wall surface, the ram 8 or the like.

  Examples of the cooling medium C include water, ice, and dry ice. The water used as the cooling medium C can be set not only at room temperature (about 25 ° C.) but also at an arbitrary temperature of about 0 ° C. to 80 ° C., for example.

  The water content adjusting mechanism 15 includes a dryer 15a and a weighing scale 15b. The water content adjusting mechanism 15 adjusts the water content to be reduced with respect to at least one of the plurality of types of non-vulcanizing compounding agents N constituting the rubber material R. In this embodiment, silica N1 is dried using a dryer 15a to adjust the weight loss. Specifically, an amount of water corresponding to the amount of water generated in the kneading chamber 4a is dried from the silica N1 by the cooling medium C introduced into the kneading chamber 4a. Then, it is confirmed by measuring with the weigh scale 15b whether or not the water content has been reduced. In this manner, silica N1 obtained by drying the same amount of water as the amount of water generated in the kneading chamber 4a by the cooling medium C introduced into the kneading chamber 4a is prepared in advance with respect to the initial silica N1.

  A wattmeter 12 a is attached to the control unit 12. Instantaneous power required for rotationally driving the rotor 3 is sequentially detected by the wattmeter 12a. Data detected by the wattmeter 12 a is input to the control unit 12. The control unit 12 calculates an integrated electric energy obtained by integrating the instantaneous electric power, and can grasp the electric energy (load acting on the rotor 3) required for the rotational driving of the rotor 3 in an arbitrary kneading period. In addition, the rotational speed of the rotor 3, the ram pressure, and the like are input to the control unit 12.

  The control unit 12 controls the rotational speed of the rotor 3, the ram pressure (the ram's vertical movement), the operation of the refrigerant supply mechanism 14, and the like. According to the specifications of the rubber material R to be kneaded, the control unit 12 has an optimum predetermined temperature range of the rubber material R to be maintained when kneading, the timing of supplying the cooling medium C from the refrigerant supply mechanism 14, and the supply amount thereof. Etc. are entered. The rotational speed of the rotor 3 is controlled based on the detection data from the temperature sensor 11. Basically, the temperature of the rubber material R being kneaded increases as the rotational speed of the rotor 3 is increased (the rotational speed is increased).

  The procedure of the rubber material kneading method of the present invention will be described below.

  The present invention is applied, for example, when a plurality of batches of rubber material R are kneaded continuously. In the closed kneader 2 in which the rubber material R has already been kneaded, the heat generated by the kneading of the rubber material R is considerably stored. Therefore, even if the cooling water circulates in the circulation path formed inside the casing forming the kneading chamber 4a or inside the rotating shaft 3a, the inside of the kneading chamber 4a (the inner wall surface of the kneading chamber 4a, the rotor 3 or the like) It is too hot.

  Therefore, in the present invention, first, as illustrated in FIG. 3, the cooling medium C is put into the kneading chamber 4a. At this time, when the rotor 3 is rotated, the cooling medium C can be widely distributed in the kneading chamber 4a. By introducing the cooling medium C, the stored heat can be taken away by the cooling medium C, and the temperature in the kneading chamber 4a can be sufficiently lowered.

  If the temperature of the cooling medium C is low, it is easy to take away a large amount of stored heat, but even if the temperature of the water used as the cooling medium C is high, a cooling effect due to the heat of vaporization can be expected. The cooling medium C is advantageous for wide distribution when sprayed.

  Next, silica N1 whose water content has been adjusted in advance as described above is put into the kneading chamber 4a and stirred by rotating the rotor 3. As a result, the cooling medium C is absorbed by the silica N1 that has been dried from the beginning.

  Thereafter, as illustrated in FIG. 4, the coupling agent N <b> 2 is charged into the kneading chamber 4 a and stirred by rotating the rotor 3. Thereby, silica N1 and coupling agent N2 are mixed and reaction is accelerated | stimulated. In this way, among the plurality of types of non-vulcanized compounding agents N to be charged, silica N1 and coupling agent N2 are charged in advance into the kneading chamber 4a and mixed in advance.

  Next, as illustrated in FIG. 5, the raw rubber G and the remaining non-vulcanized compounding agent N3 are charged into the kneading chamber 4a, and the rotor 3 is moved while oil is being charged into the kneading chamber 4a through the oil charging unit 5. The rubber material R is rotated and maintained in a predetermined temperature range (for example, 130 ° C. to 180 ° C.) and kneaded. In the present invention, the temperature in the kneading chamber 4a is sufficiently cooled by introducing the cooling medium C while the kneading chamber 4a is substantially empty. Accordingly, in the step of kneading the rubber material R, kneading can be performed at a necessary number of revolutions without suppressing the number of revolutions of the rotor 3.

  Further, the cooling medium C is introduced in order to lower the temperature in the kneading chamber 4a, but the water in the kneading chamber 4a that is increased by the cooling medium C is preliminarily dried in consideration of the amount of water. Absorbed by N1. Therefore, the amount of water in the kneading chamber 4a becomes appropriate, and it is possible to avoid the problem that excessive sliding occurs between the rubber material R and the rotor 3 and the kneading cannot be sufficiently performed. Therefore, it becomes possible to obtain a rubber material R with stable quality. In the rubber material R in which the silica N1 and the coupling agent N2 are not blended, the water content is adjusted to be reduced as in the silica N1 described above with respect to the non-vulcanized compounding agent N such as carbon black.

  In this embodiment, the cooling medium C is charged into the kneading chamber 4 a from the refrigerant charging portion 13, and the non-vulcanizing compounding agent N is charged into the kneading chamber 4 a from the compounding agent charging portion 9. If both charging parts are the same, there is a risk that the unvulcanized compounding agent N is solidified by the moisture of the cooling medium C and the charging part is clogged. preferable.

DESCRIPTION OF SYMBOLS 1 Kneading apparatus 2 Sealed kneading machine 3 Rotor 3a Rotating shaft 3b Blade 4a Kneading chamber 4b Ram chamber 5 Oil charging unit 6 Rubber charging unit 7 Hopper 8 Ram 9 Compounding agent charging unit 10 Discharge door 11 Temperature sensor 12 Control unit 12a Power meter 13 Refrigerant charging part 14 Refrigerant charging mechanism 14a Storage tank 14b Nozzle 14c Supply path 15 Water content adjusting mechanism 15a Dryer 15b Weigh scale C Cooling medium G Raw rubber N (N1, N2, N3) Non-vulcanized compounding agent R Rubber material

Claims (5)

In a rubber material kneading method in which a rubber material composed of raw rubber and a plurality of types of non-vulcanizing compounding agents is kneaded by a closed kneader,
A cooling medium is introduced into the kneading chamber of the closed kneader to lower the temperature in the kneading chamber, and then the water content is reduced and adjusted in advance according to the amount of water generated in the kneading chamber by the introduced cooling medium. A part of the non-vulcanizing compound containing one kind of the non-vulcanizing compound is added to the kneading chamber in advance and stirred by rotating a rotor provided in the kneading chamber, Next, the rubber material is kneaded while maintaining the rubber material in a predetermined temperature range by charging the raw rubber and the remaining type of non-vulcanizing compounding agent into the kneading chamber and rotating the rotor. To knead rubber material.   Silica and a coupling agent are included in the non-vulcanized compounding agent, and the silica and the coupling agent are preceded in the kneading chamber as a non-vulcanized compounding agent in which the water content is adjusted to reduce the water content. The method for kneading a rubber material according to claim 1 to be charged.   The rubber material kneading method according to claim 1, wherein water, ice, or dry ice is used as the cooling medium.   The method for kneading a rubber material according to any one of claims 1 to 3, wherein the cooling medium and the non-vulcanized compounding agent are charged into the kneading chamber from separate charging portions. A sealed kneader having a rotor installed in a kneading chamber and kneading a rubber material composed of raw rubber and a plurality of types of non-vulcanizing compounding agents in the kneading chamber by rotating the rotor. In the rubber material kneading apparatus provided,
The non-vulcanizing system includes a refrigerant charging mechanism for charging a cooling medium into the kneading chamber, and a moisture content adjusting mechanism, and the non-vulcanizing system according to the amount of water generated in the kneading chamber by the cooling medium charged into the kneading chamber For at least one of the compounding agents, the water content is adjusted in advance by the water content adjusting mechanism, and the cooling medium is introduced into the kneading chamber to lower the temperature in the kneading chamber. A part of the non-vulcanized compounding agent including the non-vulcanized compounding agent whose amount of water has been adjusted in advance is previously introduced into the kneading chamber and stirred by rotating the rotor, and then The raw material rubber and the remaining types of the non-vulcanized compounding ingredients are put into the kneading chamber and the rotor is rotated so that the rubber material is kneaded while maintaining a predetermined temperature range. Characterized by Kneading apparatus of the non-material.

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