JP2014098073A - Method for preparing rubber composition for tire, and rubber composition for tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a rubber composition for tires, which allows wet grip property and rolling resistance of a tire to be improved by blended chitin or chitosan and haves excellent reinforcing effect, and to provide the rubber composition for tires.SOLUTION: The method for preparing the rubber composition for tires comprises the steps of: injecting a dispersion fluid L, which is obtained by dispersing a material M being one of chitin and chitosan in water and is pressurized highly, to make the injected fluid collide with a collision object body 6 so that the material M is micronized to have short fiber-like shapes having 10-100 nm average fiber diameter; dispersing the micronized material M1 in water W to obtain a micronized dispersion fluid L1; mixing the micronized dispersion fluid in a diene rubber R-dissolved rubber composition solution RL to obtain a mixture; and drying the mixture to obtain the solidified rubber composition RS.

Description

  The present invention relates to a method for producing a tire rubber composition and a tire rubber composition. More specifically, the blended chitin or chitosan improves the wet grip property and rolling resistance of the tire and has an excellent reinforcing effect. The present invention relates to a method for producing a tire rubber composition and a tire rubber composition.

  By using a silica-containing rubber for the tread rubber of a tire, the wet grip property and rolling resistance (low fuel consumption) of the tire can be improved. In recent years, demands for these performances are increasing, and it is difficult to meet these demands only by using silica-containing rubber. On the other hand, various proposals have been made to improve wet grip properties and rolling resistance by using a rubber composition containing chitin, chitosan, starch, cellulose and the like for tread rubber (see, for example, Patent Documents 1 to 4).

  For example, in order to improve wet grip and rolling resistance by adding chitin or chitosan to rubber, it is necessary to reduce the size to some extent, but it is difficult to sufficiently reduce these biopolymers. It was. Therefore, there is room for improvement in order to obtain a sufficient improvement effect. Further, if the chitin or chitosan blended in the rubber is not sufficiently refined, there is a problem that the rubber strength (wear resistance, etc.) is adversely affected.

Japanese Patent Laid-Open No. 5-287130 Japanese Patent Laid-Open No. 5-279512 Japanese Patent Laid-Open No. 10-17713 JP 2001-89599 A

  An object of the present invention is to improve the wet grip property and rolling resistance of a tire with the blended chitin or chitosan, and to provide a tire rubber composition manufacturing method and a tire rubber composition capable of obtaining an excellent reinforcing effect Is to provide.

  In order to achieve the above object, a method for producing a rubber composition for a tire according to the present invention includes high-pressure injection of a dispersed fluid in which one of chitin and chitosan is dispersed in water to cause collision with a collision object. After the above-mentioned material is fibrous and refined to an average fiber diameter of 10 nm to 100 nm, and the refined dispersion fluid in which the refined material is dispersed in water is mixed with the rubber composition solution in which the diene rubber is dissolved. A solid rubber composition is obtained by drying.

  The rubber composition for tires of the present invention is characterized in that either one of chitin and chitosan, which are fibrous and refined to an average fiber diameter of 10 nm to 100 nm, is blended with a diene rubber.

  ADVANTAGE OF THE INVENTION According to this invention, the rubber composition by which any one material of the chitin or chitosan refined | miniaturized by fiber shape and the average fiber diameter of 10-100 nm was mix | blended with the diene-type rubber | gum can be obtained. When this rubber composition is used as a tread rubber of a tire, the wet grip property and rolling resistance of the tire are improved by the refined chitin or chitosan as compared with the case where the refined product is not refined, and excellent. A reinforcing effect can be obtained.

It is explanatory drawing which illustrates the process of refining chitin or chitosan. It is explanatory drawing which shows another example of the process of refine | miniaturizing chitin or chitosan. It is explanatory drawing which illustrates the process of drying the rubber composition solution which mixed the refinement | distribution dispersion fluid.

  Hereinafter, the manufacturing method of the rubber composition for tires and the rubber composition for tires of the present invention are explained based on an embodiment.

  In the method for producing a rubber composition for a tire according to the present invention, either the chitin or the chitosan material M is used. For example, as the material M, purified chitin and purified chitosan subjected to deproteinization and decalcification treatment are used. Then, one of the materials M is mixed and dispersed in the water W to prepare a dispersion fluid L. The concentration of the material M in the dispersion fluid L is about 1 to 20% by mass.

  Next, the dispersion fluid L is jetted at high pressure to refine the material M. For this miniaturization, for example, a single nozzle chamber type high-pressure injection device 1A shown in FIG. 1 is used. In the high-pressure injection device 1A, the dispersion fluid L is pressurized to an ultrahigh pressure of 100 to 245 MPa, and is injected through the inflow portion 2 from the fine nozzle 3a (about φ0.1 to 0.8 mm) of the orifice portion 3 at a high pressure.

  The discharge flow from the nozzle 3a becomes a high-speed jet of about 440 to 700 m / s, and a high shearing force is generated in the orifice portion 3 accelerated to that speed. By making the thickness t of the orifice part 3 as extremely thin as about 0.4 mm, almost 100% of the pressure energy can be converted into the velocity energy of the injection.

  Further, cavitation bubbles are generated in a high-speed jet flow of about 440 to 700 m / s, and a strong impact force is generated by the disappearance of the bubbles. Cavitation can be efficiently generated by providing the impact enhancing region 4 having a certain volume after expanding the diameter on the rear side of the orifice portion 3. The Reynolds number Re of the dispersion fluid L immediately after jetting from the nozzle 3a is in the range of 2266 ≦ Re ≦ 3885, for example. The dispersion fluid L that has passed through the impact enhancement region 4 collides with a collision target body 6 made of a ball or flat ceramic hard body provided in the collision chamber 5 and is discharged from the discharge unit 7.

  The processing by the high-pressure injection device 1A is performed once or repeated a plurality of times (50 times or less, 30 times or less, or 10 times or less as necessary). The fibrous material M has a fiber diameter reduced by unwinding the fibers due to the shear force when passing through the nozzle 3a, the cavitation impact force caused by submerged jetting, and the impact force caused by colliding with the collision object 6. The fiber is cut to shorten the fiber length.

  Thus, the material M disperse | distributed to the dispersion fluid L is made into the material M1 refined | miniaturized by the average fiber diameter of 10 nm-100 nm in the shape of a short fiber form or medium-long fiber form. For example, it is a short fiber and is subdivided into an average fiber diameter of 10 nm to 100 nm. The short fiber shape means a fiber length of about 100 nm to 10 μm.

  The aspect ratio (fiber diameter / fiber length) of the refined material M1 is about 1-1000. The average fiber diameter of the refined material M1 is more preferably about 10 nm to 50 nm, and further preferably about 15 nm to 25 nm.

  In order to subdivide the material M, the oblique collision chamber type high-pressure injection apparatus 1B illustrated in FIG. 2 can also be used. In the high pressure injection device 1B, the inflow portions 2 are connected to both sides of the impact chamber 5. In the high pressure injection device 1 </ b> B, the dispersion fluid L is pressurized to an ultrahigh pressure of 100 to 245 MPa, and is injected at a high pressure from the fine nozzle 3 a of the orifice portion 3 through each inflow portion 2. The dispersed fluids L jetted opposite to each other collide in the collision chamber 5. That is, in this high-pressure injection device 1B, the other dispersion fluid L that has been subjected to high-pressure injection so as to face one of the dispersion fluids L that has been subjected to high-pressure injection is used as the collision object 6 provided in the high-pressure injection device 1A shown in FIG. Use.

  Also in the case of using this high-pressure injection device 1B, the process is performed once or repeated a plurality of times (as required, 50 times or less, 30 times or less, or 10 times or less). The fibrous material M has a shearing force when the dispersion fluid L passes through the nozzle 3a, a cavitation impact force due to submerged jetting, an impact force when the materials M collide opposite each other, and a shear due to an increase in relative velocity in the opposing jet. The force unwinds the fibers and reduces the fiber diameter, cutting the fibers and shortening the fiber length. In this way, the material M dispersed in the dispersion fluid L is changed to a material M1 that is in the form of short fibers, medium or long fibers, and is refined to an average fiber diameter of 10 nm to 100 nm. For example, it is a short fiber and is subdivided into an average fiber diameter of 10 nm to 100 nm.

  Next, the refined material M1 is dispersed in water W to prepare a refined dispersion fluid L1. The amount of the material M1 in the finely dispersed fluid L1 is appropriately adjusted so as to be a target part by weight after drying.

  Next, the finely dispersed fluid L1 is mixed with the rubber composition solution RL in which the diene rubber R is dissolved. Examples of the diene rubber R include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), and the like.

  As the rubber composition solution RL, rubber latex or a rubber solution is used, but if rubber latex is used, the handling property is good. As the solvent for the rubber solution, for example, toluene, xylene, chloroform, tetrahydrofuran, hexane, heptane, octane or a mixture of two or more of these can be used.

  Then, the rubber composition solution RL mixed with the finely dispersed fluid L1 is dried to obtain a solidified rubber composition RS containing the finely divided material M1. In order to dry the rubber composition solution RL mixed with the finely dispersed fluid L1, for example, a pulse combustor 8 is used as shown in FIG. The pulse combustor 8 includes a combustion unit 9 provided with a fuel supply port 12 and a starter plug 13. A suction port 10 and a tail pipe 11 are connected to the front and rear of the combustion unit 9, respectively. An injection nozzle 14 and a drying hopper 15 are provided on the rear side of the tail pipe 11.

  In the pulse combustor 8, combustion air A is introduced into the combustion unit 9 from the suction port 10, and fuel F such as natural gas, propane gas, kerosene, etc. is supplied from the fuel supply port 12, and is ignited by the starter plug 13. Blasting occurs. Then, the explosion combustion exhaust gas is ejected to the drying hopper 15 through the tail pipe 11. A rubber composition solution RL mixed with the finely dispersed fluid L1 is sprayed from the spray nozzle 14 and brought into contact with the blown blast combustion exhaust gas.

  By this contact, the rubber composition solution RL is dried instantaneously (for example, about 0.01 seconds). That is, dehydration and drying are instantaneously performed by a combination of shock wave (frequency: 60 to 1000 Hz) by pulse combustion, explosion generated gas, alternating flow, gas temperature (40 ° C. to 200 ° C.), and the like. The drying temperature in this case is preferably 140 ° C. or lower, more preferably 40 to 100 ° C. As a result, a solid rubber composition RS is produced in which the diene rubber R is blended with a material M1 in which either chitin or chitosan is fibrous and refined to an average fiber diameter of 10 nm to 100 nm.

  Other drying methods include natural drying, oven drying, freeze drying, spray drying, and the like. The drying temperature is room temperature (usually 20 to 30 ° C.) in the case of natural drying, and preferably 40 to 80 ° C. in the case of oven drying.

  This rubber composition RS is used as a molded member of a tread rubber for a green tire, and becomes a tread rubber for a tire manufactured by vulcanizing a green tire. In the rubber composition RS of the present invention, one material M of chitin or chitosan is blended, and this material M is, for example, in a short fiber shape and is refined to an average fiber diameter of 10 nm to 100 nm. That is, the material M1 refined more finely than chitin or chitosan blended conventionally is finely dispersed to improve the wet grip property of the tire. Further, since the interaction between the material M1 and the rubber, which are made finer than before, increases, rolling resistance (low fuel consumption) is improved. Furthermore, it was found that an excellent reinforcing effect can be obtained by the refined material M1.

  In the rubber composition RS, the amount of the refined material M1 is preferably 2 parts by mass to 20 parts by mass, more preferably 2 parts by mass to 10 parts by mass with respect to 100 parts by mass of the diene rubber. . If the blending amount of the refined material M1 is less than 2 parts by mass, the effect of improving wet grip properties and rolling resistance becomes small, and if it exceeds 20 parts by mass, the rolling resistance tends to be adversely affected.

  Further, when the rubber composition solution RL in which the diene rubber R is dissolved is dried, it is preferably dried instantaneously using the pulse combustor 8 described above. By drying instantaneously, the miniaturized materials M1 are less likely to agglomerate and the reinforcing effect can be significantly improved.

  The present invention can be applied not only to a rubber composition containing carbon black but also to a rubber composition containing silica (silica and silane coupling agent).

  As shown in Table 1, with respect to 100 parts by mass of natural rubber, any one material of refined chitin, refined chitosan, chitin, and chitosan, and each compounding agent are expressed in parts by mass shown in Table 1. Thirteen types of unvulcanized rubber compositions (conventional examples, Examples 1 to 8, Comparative Examples 1 to 4) were prepared by blending. Each unvulcanized rubber composition was formed into a sheet and vulcanized at 160 ° C. for 15 minutes to prepare a vulcanized rubber sheet (thickness 2 mm). The rubber physical properties of this vulcanized rubber sheet were measured. The results are shown in Table 1.

Preparation of Rubber Composition Conventional Example and Comparative Example 3, 4: 60% concentrated natural rubber latex was dried by removing water under reduced pressure by a general vacuum freeze-drying method to obtain a solid rubber composition. . A compounding agent shown in Table 1 was mixed with the solidified rubber composition by a general method to obtain an unvulcanized rubber composition.

  Examples 1 to 4: A dispersion fluid in which either one of chitin and chitosan is dispersed in water is jetted at high pressure to collide with an object for collision, so that it has a short fiber shape and has an average fiber diameter of 10 nm to 100 nm. A rubber composition obtained by mixing a refined dispersion fluid obtained by dispersing a liquefied material in water with 60% concentrated natural rubber latex, and then removing the water under reduced pressure by a general vacuum freeze-drying method, followed by drying and solidifying. I got a thing. A compounding agent shown in Table 1 was mixed with the solidified rubber composition by a general method to obtain an unvulcanized rubber composition.

  Examples 5 to 8: A dispersion fluid in which any one material of chitin or chitosan is dispersed in water is jetted at high pressure to collide with an object for collision, so that it has a short fiber shape and has an average fiber diameter of 10 nm to 100 nm. A refined dispersion fluid obtained by dispersing the material obtained in water was mixed with 60% concentrated natural rubber latex, and then dried by the above-described drying method using a pulse combustor to obtain a solid rubber composition. . A compounding agent shown in Table 1 was mixed with the solidified rubber composition by a general method to obtain an unvulcanized rubber composition.

  Comparative Example 1: A dispersion fluid in which chitin powder (average particle size: 1 μm) manufactured by Nacalai Tesque Co., Ltd. was dispersed in water was mixed with 60% concentrated natural rubber latex. It was removed and dried to obtain a solid rubber composition. A compounding agent shown in Table 1 was mixed with the solidified rubber composition by a general method to obtain an unvulcanized rubber composition.

  Comparative Example 2: Fine powder chitosan (average particle size 50 μm) manufactured by Yaizu Suisan Kagaku Kogyo Co., Ltd. was mixed in water with 60% concentrated natural rubber latex, and then reduced in pressure by a general vacuum freeze-drying method. Under the condition, water was removed and dried to obtain a solid rubber composition. A compounding agent shown in Table 1 was mixed with the solidified rubber composition by a general method to obtain an unvulcanized rubber composition.

Compounding agent Zinc Hana: “Zinc oxide 3 types” manufactured by Shodo Chemical Industry Co., Ltd.
Stearic acid: “Bead stearic acid” manufactured by NOF Corporation
Silica: “Zeosil 1165MP” manufactured by Rhodia
Carbon black: “Seast 6” manufactured by Tokai Carbon
Anti-aging agent: “6PPD” manufactured by Surexis
Silane coupling agent: “Si69” manufactured by Degussa
Oil: "Extract No. 4 S" manufactured by Showa Shell Sekiyu KK
Sulfur: “Fine powder sulfur with Jinhua seal oil” manufactured by Tsurumi Chemical Co., Ltd.
Vulcanization accelerator 1: “Noxeller CZ-G” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Vulcanization accelerator 2: "Sunceller DG" manufactured by Sanshin Chemical Industry Co., Ltd.

Measurement of rubber physical properties Hardness (20 ° C.): Each vulcanized rubber sheet was measured for Lübke JIS hardness at a temperature of 20 ° C. according to JIS K6253. The numerical values in Table 1 are indexed with the conventional example as 100 as a reference, and the larger the numerical value, the higher the hardness.

  100% modulus: A JIS No. 3 dumbbell-shaped test piece was punched out from each vulcanized rubber sheet, and a tensile test at a tensile speed of 500 mm / min was performed in accordance with JIS K6251 to measure 100% modulus at room temperature. The numerical values in Table 1 are indexed with the conventional example as 100 as a reference. The larger the numerical value, the larger the modulus and the greater the reinforcing effect of the blended material.

  Breaking strength: A JIS No. 3 dumbbell-shaped test piece was punched out from each vulcanized rubber sheet, a tensile test at a tensile speed of 500 mm / min was performed in accordance with JIS K6251, and the tensile breaking strength was measured at room temperature. The numerical values in Table 1 are indexed with the conventional example as 100 as a reference, and the larger the numerical value, the higher the breaking strength and the better the wet grip property.

  Measurement of tan δ: The dynamic viscoelasticity of each vulcanized rubber sheet was measured by using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho, tan δ at an initial strain of 10%, an amplitude of ± 2%, a frequency of 20 Hz, and a temperature of 60 ° C. did. The numerical values in Table 1 are indexed with the conventional example as 100 as a reference, and the smaller the numerical value, the smaller the tan δ and the better the rolling resistance.

  From the results of Table 1, Examples 1 to 8 containing refined chitin or chitosan were wet grip property (breaking strength) and rolling resistance (60 ° tan δ) as compared with the conventional example and Comparative Examples 1 to 4. ) Will improve. Furthermore, it can be seen that an excellent reinforcing effect (100% modulus) can be obtained. Moreover, it turns out that the reinforcement effect improves notably in Examples 5-8 using the drying method by a pulse combustor.

  Table 1 describes a rubber composition based on natural rubber, but based on another diene rubber such as isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), etc. It has been confirmed that similar results can be obtained with the rubber composition.

DESCRIPTION OF SYMBOLS 1A High pressure injection apparatus 1B High pressure injection apparatus 2 Inflow part 3 Orifice part 3a Nozzle 4 Impact enhancement part 5 Collision chamber 6 Collision object 7 Discharge part 8 Pulse combustor 9 Combustion part 10 Suction port 11 Tail pipe 12 Fuel supply port 13 Starter plug 14 Injection nozzle 15 Drying hopper A Combustion air F Fuel L Dispersion fluid L1 Fine dispersion fluid M Material (chitin or chitosan)
M1 Fine material R Diene rubber RL Rubber composition solution RS Rubber composition W Water

Claims (7)

  The dispersion fluid in which either one of chitin and chitosan is dispersed in water is jetted at high pressure to collide with the object to be collided, so that the material is refined to an average fiber diameter of 10 nm to 100 nm. For a tire characterized by obtaining a solid rubber composition by mixing a refined dispersion fluid obtained by dispersing a material obtained in water with a rubber composition solution in which a diene rubber is dissolved and then drying the mixture. A method for producing a rubber composition.   The other dispersion fluid jetted oppositely is made to collide with the other dispersion fluid jetted in the opposite direction by making the other dispersion fluid jetted at a high pressure to face the dispersion fluid jetted at a high pressure. The manufacturing method of the rubber composition for tires of Claim 1.   The method for producing a rubber composition for a tire according to claim 1 or 2, wherein the rubber composition solution is a rubber latex.   The rubber composition solution mixed with the finely dispersed fluid is instantaneously dried by being injected and brought into contact with a blast combustion exhaust gas ejected from a pulse combustor to obtain the solidified rubber composition. The manufacturing method of the rubber composition for tires in any one of claim | item 1-3.   The manufacturing method of the rubber composition for tires in any one of Claims 1-4 which mix | blend 2-20 mass parts of said materials with respect to 100 mass parts of said diene rubbers.   A rubber composition for tires, characterized in that any one material of chitin or chitosan which is fibrous and refined to an average fiber diameter of 10 nm to 100 nm is blended with a diene rubber.   The tire rubber composition according to claim 6, wherein 2 to 20 parts by mass of the material is blended with respect to 100 parts by mass of the diene rubber.

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