JP2012121942A - Rubber composition and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a rubber composition dispensing with additional facility investment, without lowering productivity and sufficiently decreasing the ratio of an unreacted silane coupling agent and to provide the rubber composition produced by the production method.SOLUTION: There is provided the method for producing the rubber composition by compounding a raw rubber for tire, silica and a silane coupling agent. The production method comprises a kneading process to knead a rubber material obtained by compounding 100 pts.mass of a raw rubber for tire with 5-150 pts.mass of silica based on 100 pts.mass of the raw rubber for tire together with the silane coupling agent using an internal kneader and, successive to the kneading process, a holding process to hold the kneaded rubber mass in a hot atmosphere under the closed kneader for a definite time and supply the rubber mass with heat sufficient for reacting the silica with the silane coupling agent. There is further provided the rubber composition produced by the method for producing the rubber composition.

Description

  The present invention relates to a rubber composition and a method for producing the same, and more particularly to a method for producing a rubber composition in which silica and a silane coupling agent are sufficiently reacted, and a rubber composition produced using the production method.

  In recent years, in pneumatic tires, there has been a strong demand for both low fuel consumption and improved wet grip performance.To meet this demand, silica is used as a reinforcing agent in rubber compositions used in extruded products such as treads. Blending is done.

  However, since sufficient reinforcement cannot be obtained with silica alone, conventionally, in the kneading process, a silane coupling agent containing an alkoxyl group is added together, and the reinforcement between the silica and the silane coupling agent is achieved. It is intended to improve. However, in the conventional kneading step, it has been difficult to sufficiently complete the reaction between silica and the silane coupling agent.

  As a countermeasure, it was considered to sufficiently supply the amount of heat necessary for the reaction between the silica and the silane coupling agent by kneading the rubber for a long time, but when this kneading method was adopted, Due to the kneading for a long time, the productivity may be deteriorated, or the rubber may be gelled and cannot be produced.

  Therefore, as a method of obtaining sufficient reinforcement with silica, conventionally, it is common to mix and knead more silane coupling agents than necessary, assuming that unreacted silane coupling agents remain. Was done.

  However, when this kneading method is employed, the reaction of the remaining unreacted silane coupling agent occurs by heating the kneaded rubber composition in the extrusion step provided after the kneading step. There has been a new problem in that alcohol such as ethanol is generated to generate bubbles in the extruded product.

  Further, as a kneading method for suppressing deterioration of productivity and gelation of rubber in the kneading step and sufficiently reacting with the silane coupling agent, a heating chamber such as an oven is installed, and the rubber composition is heated to 40 to 100 ° C. There has also been proposed a method in which the amount of heat is given by heating within the range (for example, Patent Document 1).

  However, this method requires new capital investment, and it cannot be said that a sufficient amount of heat can be supplied to sufficiently reduce the unreacted rate of the silane coupling agent.

JP 2007-246929 A

  Therefore, in view of the above problems, the present invention does not require a new capital investment, and does not cause deterioration in productivity, and a method for producing a rubber composition in which the unreacted rate of the silane coupling agent is sufficiently reduced. And a rubber composition produced using the production method.

In order to solve the above problems, a method for producing a rubber composition according to the present invention comprises:
A rubber composition production method for producing a rubber composition by blending silica and a silane coupling agent into a raw material rubber for tires,
A rubber material in which 100 parts by mass of raw rubber for tires and 5-150 parts by mass of silica is blended with respect to 100 parts by mass of raw rubber for tires is kneaded together with a silane coupling agent using a closed kneader. A kneading step,
Subsequent to the kneading step, the rubber lump obtained by kneading is held for a predetermined time in a high-temperature atmosphere below the closed kneading machine, and the rubber lump has a heat amount necessary for the reaction between silica and the silane coupling agent. A holding process to supply;
It is characterized by having.

The method for producing the rubber composition includes
Wherein the quantity of heat Q ₁ generated by the kneading in the kneading step, based on the total mixing amount of heat Q which is the grand total of the amount of heat Q ₂ to which is supplied by holding the rubber mass in said holding step, preparation of the rubber composition It is characterized by controlling.
However, Q = ΣQ ₁ + ΣQ ₂
Q ₁ = EXP [(−20 / (1.987 / 0.001)
× {1 / (T ₁ +273.16) −1 / 414.86}] × t ₁
Q ₂ = EXP [(− 20 / (1.987 / 0.001)
× {1 / (T ₂ +273.16) −1 / 414.86}] × t ₂
0.5 ≦ t ₂ ≦ 6.0
141.7 ≦ T ₂ ≦ 165.0
t ₁ : kneading time (minutes)
t ₂ : Holding time (minutes) below the closed kneader
T ₁ : Kneaded rubber temperature (° C)
T ₂ : rubber temperature (° C.) during holding below the closed kneader

The method for producing the rubber composition includes
The total mixing heat quantity Q satisfies the following formula.
8 ≦ Q ≦ 30

The method for producing the rubber composition includes
The total mixing heat quantity Q satisfies the following formula.
18 ≦ Q ≦ 30

And the rubber composition which concerns on this invention is
It is manufactured using the manufacturing method of the said rubber composition, It is characterized by the above-mentioned.

  In the present invention, after kneading a rubber material in which silica and a silane coupling agent are mixed, the rubber material is not extruded immediately, but is held for a predetermined time in a high temperature atmosphere below the closed kneader so that the rubber lump has silica and silane coupling. A holding step for supplying the amount of heat necessary for the reaction with the agent is provided. For this reason, the silane coupling agent reacts sufficiently with silica, and the generation of alcohol by the unreacted silane coupling agent in the extrusion process and the generation of bubbles in the extruded product can be suppressed. .

  And in a holding process, since it hold | maintains only in the high temperature atmosphere under a closed kneading machine, it is not necessary to make new capital investment. Further, since it is not necessary to knead the rubber for a long time, the productivity does not deteriorate and the rubber is not gelled. Furthermore, since the next rubber material can be kneaded during the holding time, productivity is not deteriorated from this point.

  In addition, since the unreacted rate of the silane coupling agent can be controlled based on the total mixing heat quantity defined by the kneading conditions (kneading time, kneaded rubber temperature) and the holding conditions (holding time, rubber temperature during holding), the rubber The production of the composition can be easily controlled.

  And the pneumatic tire excellent in wet grip performance with low fuel consumption can be provided by using the tread which consists of a rubber composition manufactured in this way.

It is a figure which shows the relationship of the unreacted rate of the rubber composition of an Example, abrasion resistance, and total mixing calorie | heat amount. It is a figure which shows the logarithmic relationship of the unreacted rate (y) of the rubber composition of an Example, and total mixing calorie | heat amount (x).

A. Basic concept of the present invention First, the basic concept of the present invention will be described.

  In the conventional kneading step, immediately after kneading, the obtained rubber lump is discharged from the closed kneader and dropped onto the extruder to form a sheet. In the kneading step, it was difficult to sufficiently complete the reaction between silica and the silane coupling agent.

On the other hand, it has been known that the following relationship exists between the amount of heat (mixing heat amount Q _M ) given to the rubber composition in the kneading step and the unreacted rate (y%) of the silane coupling agent.
y = −Aln (Q _M ) + B (A and B are constants)

From the above formula, it can be seen that in order to reduce the unreacted rate of the silane coupling agent, the mixing heat quantity Q _M may be increased.

Therefore, as a means to increase the mixing amount of heat Q _M, prolonged, a method of kneading was considered, as described above, a problem such as gelation of the productivity deteriorates and the rubber occurs, appropriate means I couldn't say that.

Therefore, the present inventor does not knead for a long time, but holds the kneaded rubber lump discharged from the closed kneader for an appropriate time in a high-temperature atmosphere on the extruder or roll below the closed kneader. by (residence be), is further supplied with heat, it reaches think that you can increase the mixing amount of heat Q _M, the result of an experiment, by employing this method, without the need for new capital investment, productivity It has been found that the unreacted rate of the silane coupling agent can be sufficiently reduced without causing problems such as deterioration of the rubber and gelation of rubber.

The constants A and B in the above formula are to change the mixing heat quantity Q _M and the unreacted rate of the silane coupling agent in the rubber composition by changing several kneading and holding (retention) conditions. On the other hand, this value varies depending on the blending, but the amount of silica usually blended in the tread, that is, when the silica is 5 to 150 parts by mass with respect to 100 parts by mass of the raw rubber, the above-described A, The change width of B is small, and A and B can be treated as constant, and the relationship between the unreacted rate of the silane coupling agent and the total amount of mixing heat (total amount of mixing heat) given during kneading and holding is almost constant. It can be treated as.

  For this reason, the unreacted rate of the silane coupling agent can be easily and accurately controlled based on the kneading conditions (kneading time, kneading temperature) and the holding conditions (holding time, holding temperature), and the silica compounding performance is sufficient. It was found that how to knead the rubber material to be drawn out can be determined quantitatively.

  Specifically, as a result of the experiment, the constants A and B of the above formula are 0.0696 and 0.2488, respectively. Based on the above-described values, the unreacted rate of the silane coupling agent and the mixing heat quantity By creating a graph showing the relationship, the required amount of heat corresponding to the unreacted rate of the desired silane coupling agent is obtained.

  The amount of heat to be supplied in the holding step is determined by determining the difference between the required amount of heat and the amount of heat given by the kneading conditions within a range that does not reduce productivity, and is held on an extruder or a roll. The required retention time can be determined from the retention temperature, and the unreacted rate of the silane coupling agent is sufficiently maintained by retaining (retaining) the rubber mass after kneading at the retention temperature. A reduced rubber composition can be easily obtained.

B. Production of Rubber Composition in the Present Invention Next, production of the rubber composition in the present invention will be described.

1. Manufacturing apparatus and manufacturing method As a manufacturing apparatus in manufacturing the rubber composition according to the present invention, a conventional closed kneader, such as a Banbury mixer or a kneader, can be used, and no new capital investment is required. .

  Moreover, as a manufacturing method, the conventional manufacturing method can be fundamentally employ | adopted except providing the holding process which hold | maintains the rubber lump obtained by kneading | mixing below the closed kneader. Then, based on the graph showing the relationship between the unreacted rate of the silane coupling agent prepared by the above-described method and the mixing calorie, the kneading temperature and kneading time, the holding temperature and the holding time in a range not reducing the productivity Should be set appropriately.

The amount of heat Q given to the rubber composition at this time is, as described above, the total amount of the amount of heat Q ₁ generated by kneading in the kneading step and the amount of heat Q ₂ supplied by holding the rubber lump in the holding step ( Total mixing calorie).

Then, when the total mixing heat quantity is expressed by an equation taking into consideration an appropriate rubber temperature at the time of holding in the lower part of the closed kneader and an appropriate holding time, it can be expressed as the following equation.
Q = ΣQ ₁ + ΣQ ₂
However, Q ₁ = EXP [(−20 / (1.987 / 0.001)
× {1 / (T ₁ +273.16) −1 / 414.86}] × t ₁
Q ₂ = EXP [(− 20 / (1.987 / 0.001)
× {1 / (T ₂ +273.16) −1 / 414.86}] × t ₂
0.5 ≦ t ₂ ≦ 6.0
141.7 ≦ T ₂ ≦ 165.0
t ₁ : kneading time (minutes)
t ₂ : Holding time (minutes) below the closed kneader
T ₁ : Kneaded rubber temperature (° C)
T ₂ : rubber temperature (° C.) during holding below the closed kneader

In the above equation, (−20 / 1.987 / 0.001) is the Arrhenius equation k = A · exp (−E / RT)
However, A: Constant independent of temperature (frequency factor)
E: Activation energy
R: Gas constant
T: Absolute temperature (K)
In corresponds to (-E / R), 414.86 corresponds to _{T 2} of the absolute temperature of the lower limit temperature 141.7 ℃ (K).

What the holding temperature T ₂ and 141.7 ° C. or more, 141.7 is less than ° C., the silica and silane coupling agent and does not sufficiently react, the characteristics of the silica compounded is due to not be sufficiently exhibited. The reason why the temperature is 165.0 ° C. or lower is that when the temperature exceeds 165.0 ° C., the sulfur atom contained in the silane coupling agent causes the crosslinking reaction to progress to gelation.

Further, the holding time t _2, is are we 0.5-6.0 minutes, due to considering the viewpoint of reaction and workability.

  Then, based on the above formula, by setting an appropriate kneading temperature and kneading time, and holding temperature and holding time, a rubber composition can be produced while controlling the unreacted rate of the silane coupling agent to be low. .

  Further, if the unreacted rate of the silane coupling agent exceeds 10%, alcohol is generated in the form of bubbles in the extrusion process and porosity (porosity) is generated in the tire. It is known that a problem will occur. For this reason, it is desirable to set the total mixing heat quantity so that the unreacted rate of the silane coupling agent is 10% or less.

  As a result of the experiment, it is preferable to set the kneading conditions and the holding conditions so that the total mixing heat quantity Q corresponding to an unreacted rate of 10% or less of the silane coupling agent is 8, and the total mixing heat quantity Q is 8 or more. .

  Further, when the unreacted rate of the silane coupling agent is 5% or less, the wear resistance of the tire can be improved. Similarly, from the results of the experiment, the kneading conditions and the holding conditions are set so that the total mixing heat quantity Q corresponding to an unreacted rate of 5% or less of the silane coupling agent is 18, and the total mixing heat quantity Q is 18 or more. Thus, a more preferable rubber composition can be produced.

  The unreacted rate of the silane coupling agent is less than 1% when the total mixing calorie Q is 30, and even if a higher calorie is applied, no further reduction can be expected, reducing productivity. End up. For this reason, it is preferable to set the kneading conditions and the holding conditions so that the total mixing heat quantity Q does not exceed 30.

  The rubber composition after the holding step is extruded in accordance with the shape of the tread at an unvulcanized stage, and is molded together with other tire members by a normal method on a tire molding machine. Molded into sulfur tires. Thereafter, a pneumatic tire excellent in fuel consumption and wet grip performance can be manufactured by heating and pressurizing the unvulcanized tire in a vulcanizer.

2. Rubber material As a material used for the rubber composition according to the present invention, various rubber materials similar to those in the past can be used in the same composition as in the prior art. Hereinafter, among various rubber materials, raw rubber, silica, and silane coupling agent related to the present invention will be described, and further, carbon black which is a reinforcing filler will be described.

(1) Raw rubber As the raw rubber, diene rubber is preferably used. Specific examples include natural rubber (NR), styrene butadiene rubber (SBR), isoprene rubber (IR), butadiene rubber (BR), and the like, which can be used in any combination.

(2) Silica Silica is blended in order to enhance the reinforcing property of the rubber composition and further improve the rolling resistance characteristics. Examples of the silica include silica produced using a wet method, silica produced using a dry method, and the like, but are not particularly limited, and one kind may be used alone. You may use combining more than a kind.

When the nitrogen adsorption specific surface area (N ₂ SA) of silica is too small, sufficient reinforcement cannot be obtained. On the other hand, when too large, the dispersibility of a silica will fall, a hysteresis loss will be increased, and rolling resistance characteristics will deteriorate. A preferable range is 170-250 m < ² > / g, and it is more preferable in it being 200-230 m < ² > / g. The N ₂ SA value of the silica described above is a value measured by the BET method according to ASTM D3037-81.

  When the amount of silica is too small, sufficient reinforcing properties cannot be obtained. On the other hand, when the amount is too large, dispersibility is lowered and hysteresis loss is increased, and rolling resistance characteristics are deteriorated. A preferable range is 5 to 150 parts by mass with respect to 100 parts by mass of the raw rubber, more preferably 10 to 80 parts by mass, and further preferably 30 to 60 parts by mass.

(3) Silane coupling agent As a silane coupling agent, generally an alkoxyl group-containing silane coupling agent is preferably used. Specific examples include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, and bis (3-triethoxysilylpropyl) disulfide. Among these, bis (3-triethoxysilylpropyl) tetrasulfide is preferable because it has a large reinforcing effect. These silane coupling agents may be used alone or in combination of two or more.

  When the amount of the silane coupling agent is too small, the viscosity of the unvulcanized rubber composition increases and the processability deteriorates. On the other hand, if the amount is too large, an effect commensurate with the increase in cost cannot be obtained. A preferable range is 1 to 20 parts by mass and more preferably 2 to 15 parts by mass with respect to 100 parts by mass of silica.

(4) Carbon black It is preferable to mix | blend carbon black as a filler with the rubber composition of this invention. Thereby, reinforcement property can be improved and abrasion resistance can be improved more. Examples of carbon black include GPF, FEF, HAF, ISAF, and SAF. One kind may be used alone, or two or more kinds may be used in combination.

When N ₂ SA of carbon black is too small, sufficient reinforcement cannot be obtained. On the other hand, if it is too large, the dispersibility is lowered and the rolling resistance characteristics are deteriorated. A preferable range is 50 to ²⁰⁰ m ² / g, and more preferably 100 to 150 m ² / g. Note that the N ₂ SA value of the carbon black described above is a value measured by the A method of JIS K6217.

  When the amount of carbon black is too small, sufficient reinforcing properties cannot be obtained. On the other hand, when the amount is too large, dispersibility is lowered and rolling resistance characteristics are deteriorated. A preferable range is 10 to 100 parts by mass with respect to 100 parts by mass of the raw rubber, more preferably 20 to 80 parts by mass, and further preferably 30 to 60 parts by mass.

  Next, based on an Example, this invention is demonstrated further more concretely.

1. Rubber material In the following Examples, each rubber material shown in Table 1 was used. Below, each rubber material shown by Table 1 is demonstrated.

(1) Raw material rubber As raw material rubber, SBR and BR were used in combination below.
SBR: Asahi Kasei Corporation, E10 (solution polymerization, terminal group: amino acid, modification rate: 51% by mass, styrene content: 39% by mass, vinyl bond content: 31% by mass, Mw / Mn: 2.1)
BR: manufactured by Ube Industries, BR150B

(2) Compounding chemical (a) Silica: manufactured by Degussa, Ultrasil VN3 (N ₂ SA: 175 m ² / g)
(B) Carbon black: Show Black N220 (N ₂ SA: 111 m ² / g) manufactured by Cabot Japan
(C) Silane coupling agent: Si69 {Bis (3-triethoxysilylpropyl) tetrasulfide} manufactured by Degussa
(D) Aromatic oil: JOMO Process X140, manufactured by Japan Nagi
(E) Wax: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., Sunnock N
(F) Antiaging agent: Nouchi 6C {N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine} manufactured by Ouchi Shinsei Chemical Co., Ltd.
(G) Stearic acid: manufactured by NOF Corporation, cocoon (h) zinc oxide: manufactured by Mitsui Kinzoku Mining Co., Ltd., zinc white No. 1 (i) sulfur: manufactured by Tsurumi Chemical Co., Ltd., powdered sulfur (j) vulcanization accelerator CZ: Nouchira N5 (N-tert-butyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Co., Ltd.
(K) Vulcanization accelerator DPG: Ouchi Shinsei Chemical Industries, Noxeller D

2. Production of rubber compound (1) 1st kneading step (including holding step after kneading)
(A) Kneading step Each of the raw rubbers and chemicals shown in the 1st kneading among the “blending contents” in Table 1 was put into a Banbury mixer and kneaded to reach 140 ° C. in 3 minutes. Kneading and holding were performed at the kneading temperature and kneading time shown in 1st kneading.

(B) Holding step After kneading, the obtained rubber mass is discharged to the lower part of the Banbury mixer, and then held at the holding temperature and holding time shown in 1st kneading among the “kneading and holding temperature and time” in Table 1. did.

(2) 2nd kneading step (including holding step after kneading)
(A) Kneading step Next, each of the chemicals shown in 2nd kneading among the “contents of blending” in Table 1 is put into a Banbury mixer together with a rubber lump and kneaded so as to reach 140 ° C. in 3 minutes. Kneading was performed at the kneading temperature and kneading time shown in 2nd kneading among “Kneading and holding temperature and time” in Table 1.

(B) Holding step After kneading, the obtained rubber lump is discharged to the lower part of the Banbury mixer, and then held at the holding temperature and holding time shown in 2nd kneading among the “kneading and holding temperature and time” in Table 1. did.

(3) Final kneading step Next, each of the chemicals shown in the final kneading in Table 1 is put into a Banbury mixer together with a rubber lump, kneaded for 3 minutes at 90 ° C, and not added. A vulcanized rubber composition was obtained.

3. Mixing heat, the heat quantity Q ₂ to which is supplied by retaining the rubber mass in heat Q ₁ and each holding step occurring by kneading in unreacted rate and the calculation of the productivity (1) each kneading step of calculating the mixing heat, under Calculated by the formula.
Q ₁ = EXP [(−20 / (1.987 / 0.001)
× {1 / (T ₁ +273.16) −1 / 414.86}] × t ₁
Where t ₁ : kneading time (minutes)
T ₁ : kneading temperature (° C.)
Q ₂ = EXP [(− 20 / (1.987 / 0.001)
× {1 / (T ₂ +273.16) −1 / 414.86}] × t ₂
Where t ₂ : holding time (minutes)
T ₂ : Holding temperature (° C.)

By summing the Q _1, Q ₂ to which obtained in the above, 1st kneading process, the mixing amount of heat for each 2nd kneading step determined sums them to obtain a total mixing quantity of heat Q. The results are shown in Table 1.

(2) Calculation of the unreacted rate of the silane coupling agent About the unvulcanized rubber composition obtained in each Example, the unreacted rate from the ratio of the peak area of unreacted Si69 extracted using liquid phase chromatography Asked. Specifically, from each unvulcanized rubber composition, unreacted Si69 was extracted with acetone, the peak area was measured by liquid phase chromatography, and the peak area measured in the same manner for Si69 before compounding. The ratio was determined. The results are shown in Table 1.

(3) Calculation of productivity The productivity of the kneading time in Example 1 (including 3 minutes for reaching the 140 ° C of the 1st kneading and the 2nd kneading) was set to 100, and the productivity was obtained by the following formula. It shows that productivity is high (a kneading amount increases), so that a numerical value is large. The results are shown in Table 1.
Productivity = (kneading time of Example 1 / kneading time of each Example) × 100

4). Manufacture and performance evaluation of vulcanized rubber and test tire (1) Manufacture of vulcanized rubber and test tire (a) Preparation of vulcanized rubber The unvulcanized rubber composition obtained in each example was treated at 170 ° C. for 15 minutes. Vulcanized rubber was obtained by press vulcanization.

(B) Preparation of test tire The unvulcanized rubber composition obtained in each example was processed into a tread shape and bonded to another tire member, and then vulcanized at 170 ° C. for 15 minutes to perform a test. Tires (tire size: 195 / 65R15) were produced.

(2) Performance evaluation (a) Abrasion resistance Using a Lambourn-type wear tester, the Lambourn wear amount of each vulcanized rubber composition was measured at room temperature, a load of 1.0 kgf, and a slip rate of 30%. The volume loss was determined from the obtained amount of lambourne wear. And the abrasion index was calculated | required by the following Formula by making the volume loss amount of Example 1 into 100. FIG. The larger the value, the higher the wear resistance (the smaller the volume loss). The results are shown in Table 1.
Wear index = (volume loss amount of Example 1 / volume loss amount of each example) × 100

(B) Grip index Each vehicle was run on a dry asphalt road test course using each test tire. The test driver evaluated the stability of control during steering at that time, and the index was displayed with Example 1 as 100. The larger the value, the higher the grip performance (driving stability) on the dry road surface. The results are shown in Table 1.

(C) Rolling Resistance Index Using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho), tan δ of each vulcanized rubber composition was measured under the conditions of 70 ° C., initial strain 10%, and dynamic strain 2%. Then, with tan δ of Example 1 being 100, the rolling resistance index was determined by the following equation. It shows that rolling resistance characteristic is excellent, so that a numerical value is large (rolling resistance is low). The results are shown in Table 1.
Rolling resistance index = (tan δ of Example 1 / tan δ of each Example) × 100

(Discussion)
As shown in Table 1, in Examples 1 to 7, the unreacted rate of the silane coupling agent decreased with an increase in total mixing calorie, and the rubber produced from Example 1 except for the holding step. It is clearly lower than the unreacted rate (20%) of the silane coupling agent measured in the composition (comparative example).

  Moreover, it can be seen from Table 1 that when the unreacted rate of the silane coupling agent is reduced, the wear resistance performance, grip performance, and rolling resistance index are improved.

  In Examples 3 and 4, although the unreacted rate of the silane coupling agent is sufficiently reduced, the kneading time in the 1st kneading and the 2nd kneading is increased, and thus the productivity is lowered.

  Next, FIG. 1 shows the relationship between the unreacted rate and wear resistance performance of the rubber composition shown in Table 1 and the total mixing heat quantity. In FIG. 1, the horizontal axis represents the total mixing heat, the left vertical axis represents the unreacted rate (%) of the silane coupling agent, and the right vertical axis represents the wear resistance performance.

  Moreover, based on Examples 5-7 which showed the result excellent in both productivity and the unreacted rate of a silane coupling agent in Table 1, FIG. 2 shows unreacted rate (y) and total of a rubber composition. The logarithmic relationship of mixing calorie | heat amount (x) is shown. In FIG. 2, the horizontal axis represents the logarithm of the total mixing heat quantity, and the vertical axis represents the unreacted rate of the silane coupling agent.

  As can be seen from FIG. 1, the unreacted rate of the silane coupling agent can be controlled to 10% or less when the total mixing calorie is 8 or more. When the unreacted ratio of the silane coupling agent is 10% or less, as described above, the alcohol is generated in the form of bubbles in the extrusion process, and the porosity (porous) is generated in the tire. The occurrence of serious problems can be suppressed.

  It can also be seen that the unreacted rate of the silane coupling agent can be controlled to 5% or less if the total mixing heat quantity is 18 or more. When the unreacted ratio of the silane coupling agent is 5% or less, as described above, it is possible to improve the wear resistance of the tire. This can also be seen from Table 1.

  In addition, as shown in FIG. 1, when the total mixing calorie Q is 30, the unreacted rate of the silane coupling agent is less than 1%, and beyond that, even if the amount of heat is increased, the unreacted rate cannot be expected to decrease. I understand.

  2 that the constants A and B are obtained. In addition to the above examples, the present inventor has confirmed that A and B hardly change even when the amount of the silane coupling agent is appropriately changed within a preferable range.

  Although the present invention has been described based on the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiments within the same and equivalent scope as the present invention.

Claims (5)

A rubber composition production method for producing a rubber composition by blending silica and a silane coupling agent into a raw material rubber for tires,
A rubber material in which 100 parts by mass of raw rubber for tires and 5-150 parts by mass of silica is blended with respect to 100 parts by mass of raw rubber for tires is kneaded together with a silane coupling agent using a closed kneader. A kneading step,
Subsequent to the kneading step, the rubber lump obtained by kneading is held for a predetermined time in a high-temperature atmosphere below the closed kneading machine, and the rubber lump has a heat amount necessary for the reaction between silica and the silane coupling agent. A holding process to supply;
A process for producing a rubber composition, comprising: Wherein the quantity of heat Q ₁ generated by the kneading in the kneading step, based on the total mixing amount of heat Q which is the grand total of the amount of heat Q ₂ to which is supplied by holding the rubber mass in said holding step, preparation of the rubber composition The method for producing a rubber composition according to claim 1, wherein the rubber composition is controlled.
However, Q = ΣQ ₁ + ΣQ ₂
Q ₁ = EXP [(−20 / (1.987 / 0.001)
× {1 / (T ₁ +273.16) −1 / 414.86}] × t ₁
Q ₂ = EXP [(− 20 / (1.987 / 0.001)
× {1 / (T ₂ +273.16) −1 / 414.86}] × t ₂
0.5 ≦ t ₂ ≦ 6.0
141.7 ≦ T ₂ ≦ 165.0
t ₁ : kneading time (minutes)
t ₂ : Holding time (minutes) below the closed kneader
T ₁ : Kneaded rubber temperature (° C)
T ₂ : rubber temperature (° C.) during holding below the closed kneader The method for producing a rubber composition according to claim 2, wherein the total mixing heat quantity Q satisfies the following formula.
8 ≦ Q ≦ 30 The method for producing a rubber composition according to claim 3, wherein the total mixing heat quantity Q satisfies the following formula.
18 ≦ Q ≦ 30   A rubber composition manufactured using the method for manufacturing a rubber composition according to any one of claims 1 to 4.

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