JP2013203803A - Rubber/cellulose master batch and rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber/cellulose master batch which can improve dispersibility of a fibrillated cellulose fiber into a rubber component and can exhibit an excellent reinforcing effect.SOLUTION: Mechanical shearing force is applied to an aqueous suspension containing a cellulose fiber and a water-soluble cellulose derivative to fibrillate the cellulose fiber. The obtained aqueous suspension, which contains the fibrillated cellulose fiber and the water-soluble cellulose derivative, is mixed with rubber latex to obtain a liquid mixture. The liquid mixture is dried to obtain the rubber/cellulose master batch. The obtained rubber/cellulose master batch is blended into a rubber composition.

Description

  The present invention relates to a rubber / cellulose masterbatch containing fibrillated cellulose fibers, a method for producing the same, and a rubber composition using the masterbatch.

  Cellulose is known to have a reinforcing effect on resins and rubbers. For example, Patent Document 1 listed below proposes using finely powdered cellulose fibers as a reinforcing agent for the purpose of increasing the rigidity of a tire rubber composition. Yes. However, such cellulose powder is in the form of particles in which fibers are intertwined, and there is room for improvement in order to obtain a high reinforcing effect utilizing the fine fiber shape of cellulose.

  Further, in Patent Document 2 below, short fibers such as cellulose are fibrillated in order to enhance the reinforcing property of the rubber composition, and water dispersion of fibrillated short fibers is performed in order to improve dispersibility in the rubber. It is disclosed that a rubber / short fiber master batch is obtained by stirring and mixing a liquid and a rubber latex and removing water from the mixed liquid. However, fibrillated cellulose fibers tend to aggregate and are difficult to disperse uniformly in the rubber component, and there is room for improvement in order to obtain a high reinforcing effect utilizing the fine fiber shape.

  In Patent Document 3 listed below, in order to improve the compatibility between microfibril cellulose and rubber, chemically modified microfibril cellulose subjected to chemical modification such as acetylation or alkyl esterification may be added to the rubber composition. It is disclosed. However, use of a water-soluble cellulose derivative for the purpose of highly dispersing microfibril cellulose is not disclosed.

  Patent Document 4 listed below discloses that a dry product obtained by combining microfibril cellulose and mineral particles is blended in a rubber composition, and that the carboxylated cellulose can be combined with the microfibril as an additive. Is disclosed. Further, this document discloses that when the dried product is used as a reinforcing filler for a polymer, the dried product is mixed with latex as a polymer. However, fibrillation of cellulose fibers in the presence of a water-soluble cellulose derivative is not disclosed.

JP-A-2005-75856 JP 2006-206864 A JP 2009-84564 A JP-T-2002-503621

  An object of the present invention is to provide a rubber / cellulose masterbatch that can exhibit an excellent reinforcing effect by improving the dispersibility of fibrillated cellulose fibers in a rubber component.

  The method for producing a rubber / cellulose masterbatch according to the present invention comprises subjecting an aqueous suspension containing cellulose fibers and a water-soluble cellulose derivative to mechanical shearing force to fibrillate the cellulose fibers, and an aqueous suspension obtained. The rubber latex is mixed and the mixed solution is dried. The rubber / cellulose masterbatch according to the present invention is produced by the production method. The rubber composition according to the present invention is obtained by blending the rubber / cellulose master batch produced by the production method.

  According to the present invention, fibrillated cellulose fibers are highly dispersed in an aqueous suspension by using a water-soluble cellulose derivative. Mixing rubber latex into such highly dispersed water suspension, drying and masterbatching improves dispersibility and adhesion of fibrillated cellulose fibers to rubber components, so excellent reinforcing effect A rubber / cellulose master batch can be obtained. Therefore, a rubber composition having high rigidity and mechanical properties can be obtained by using the master batch.

  Hereinafter, matters related to the implementation of the present invention will be described in detail.

  In the method for producing a rubber / cellulose masterbatch according to the present embodiment, the cellulose fibers are refined, that is, fibrillated by a fibrillation treatment that imparts mechanical shearing force to an aqueous suspension containing cellulose fibers and a water-soluble cellulose derivative. To do. In the aqueous suspension containing the fibrillated cellulose fiber and the water-soluble cellulose derivative thus obtained, the water-soluble cellulose derivative is adsorbed on the surface of the fibrillated cellulose fiber by hydrogen bonding, hydrophobic interaction, or the like. In particular, a water-soluble cellulose derivative having a cellulose molecular skeleton is considered to be effectively adsorbed to fibrillated cellulose fibers. The water-soluble cellulose derivative adsorbed in this manner acts as a protective colloid to inhibit aggregation of fibrillated cellulose fibers due to hydrogen bonding, and thus the fibrillated cellulose fibers are highly dispersed in the suspension. it is conceivable that. In particular, by fibrillating (that is, fibrillation treatment) in the presence of a water-soluble cellulose derivative, the water-soluble cellulose derivative is more effectively adsorbed on the surface of the fibrillated cellulose fiber, and the fibrillated cellulose fiber is highly dispersed. Can be demonstrated.

  In the present embodiment, as the cellulose fiber to be defibrated, cellulose fibers (pulp) prepared from various natural plant fibers such as wood, rice husk, straw, and bamboo can be used. Preferably, powdered cellulose fibers obtained by chemically treating natural plant fibers with chemicals such as sodium hydroxide or ozone are used. The average particle diameter of the powdery cellulose fiber is not particularly limited, but is preferably 100 μm or less, more preferably 1 to 50 μm. Here, the average particle diameter is an average particle diameter (50% integrated value particle diameter) obtained by a laser diffraction / scattering method.

As the water-soluble cellulose derivative, water-soluble cellulose ether in which hydrogen atoms of hydroxyl groups of cellulose molecules are appropriately substituted with other groups so that hydrogen bonding between the hydroxyl groups does not occur can be used. More specifically, it is a cellulose derivative represented by the following formula (1), and three Rs in the formula are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxy group having 1 to 6 carbon atoms. It is an alkyl group or a carboxyalkyl group having 1 to 6 carbon atoms, and the original three hydrogen atoms are appropriately substituted with these alkyl group, hydroxyalkyl group and / or carboxylalkyl group. Note that n is an integer of 1 or more.

Specific examples of the water-soluble cellulose derivative include alkyl celluloses such as methyl cellulose (in formula (1), R = H or CH ₃ ) and ethyl cellulose (in formula (1), R = H or CH ₂ CH ₃ ); hydroxyethyl cellulose (In formula (1), R = H or (CH ₂ ) ₂ OH) or the like hydroxyalkyl cellulose; hydroxymethyl methyl cellulose (in formula (1), R = H, CH ₃ or CH ₂ OH), hydroxyethyl methyl cellulose ( wherein (1), R = H, CH 3 or _{(CH 2) 2} OH), in hydroxypropylmethyl cellulose (equation (1), R = H, CH 3 or _CH 2 CHOHCH _3), hydroxyethyl cellulose (wherein ( _{1), R = H, CH 2 CH} 3 or _{(CH 2)} 2 OH) hydroxyalkyl alkyl such as Cellulose; (wherein (1), R = H, CH 2 COOH) carboxymethylcellulose include carboxyalkyl cellulose, such as these can be used singly or in combination of any two or more. Among these, at least one selected from the group consisting of alkylcellulose, hydroxyalkylcellulose and hydroxyalkylalkylcellulose is used as a water-soluble cellulose derivative having a hydrophobic functional group in order to enhance the adsorptivity to fibrillated cellulose fibers. It is preferably at least one selected from the group consisting of alkyl cellulose and hydroxyalkyl alkyl cellulose.

  The degree of etherification (substitution degree) of the water-soluble cellulose derivative is in the range of 0.1 to 3.0, usually 0.1 to 2.5. Although not particularly limited, the degree of etherification is preferably in the range of 0.2 to 2.0, and more preferably in the range of 0.5 to 1.5. The degree of etherification is the number of ether substituents per unit of anhydrous glucose.

  The aqueous suspension used for the defibrating treatment contains the cellulose fiber and the water-soluble cellulose derivative, that is, a slurry in which the cellulose fiber is dispersed in water. This can be prepared by mixing and stirring the cellulose fiber and water-soluble cellulose derivative in water. The water-soluble cellulose derivative is dissolved in water and hydrogen bonds and hydrophobicity are formed on the surface of the cellulose fiber in the aqueous suspension. It is adsorbed by interaction. Although the density | concentration of the cellulose fiber in this water suspension is not specifically limited, It is preferable that it is 0.5-30 mass%, More preferably, it is 1-20 mass%. The water-soluble cellulose derivative is preferably added in the range of 0.1 to 50% by mass with respect to the cellulose fiber, that is, the amount of the water-soluble cellulose derivative is 0.1 to 100 parts by mass of the cellulose fiber. It is preferable that it is 50 mass parts, More preferably, it is 0.1-25 mass parts, More preferably, it is 1-10 mass parts.

  The defibrating treatment that imparts mechanical shearing force to the aqueous suspension is not particularly limited, and examples thereof include a high-pressure homogenizer, a jet mill, a ball mill, and the like in addition to a grinding treatment by a stone mill method (other names: disk mill, grinder). It is done. Here, in the stone mill method, cellulose fibers are refined (that is, fibrillated) by passing the aqueous suspension through a rubbing portion arranged with a plurality of abrasive grain plates facing each other. In the aqueous suspension thus fibrillated, the cellulose fibers are dispersed in water in a fibrillated (microfibrillated) state, and the water-soluble cellulose derivative is bonded to the surface of the fibrillated cellulose fibers with hydrogen bonds and hydrophobicity. The fibrillated cellulose fibers are highly dispersed by being adsorbed by sexual interaction and acting as a protective colloid.

  Although the diameter (namely, fiber diameter) of a fibrillated cellulose fiber is not specifically limited, It is preferable that an average fiber diameter exists in the range of 0.003-10 micrometers, More preferably, it is 0.01-1 micrometer. Further, the length of the fibrillated cellulose fiber (that is, fiber length) is not particularly limited, but the average fiber length is preferably in the range of 1 to 1000 μm. Here, as for the average fiber diameter, ten fibrillated cellulose fibers are randomly extracted from a scanning electron microscope observation (SEM) image, the short diameter is measured, and the arithmetic average is defined as the average fiber diameter. The average fiber length is measured according to JIS P8121 using a fiber length measuring machine (FS-200) manufactured by KAJANI.

  In the method for producing a rubber / cellulose masterbatch according to this embodiment, the water suspension that has been defibrated as described above and rubber latex are mixed, and the mixture is dried. Thus, the fibrillated cellulose fiber physically surface-modified by adsorption of the water-soluble cellulose derivative is further mixed with the rubber latex and dried, but due to the presence of the water-soluble cellulose derivative, dispersibility in the rubber component and It is considered that the adhesion with the rubber component is enhanced, and as a result, a high reinforcing effect is exhibited.

  As the rubber latex, in addition to a synthetic rubber latex synthesized by an emulsion polymerization method, a natural rubber latex (for example, a field latex, a concentrated latex, etc.) or a latex obtained by emulsifying and dispersing a rubber synthesized by a solution polymerization method in water. Various rubber latexes can be used. The content of the rubber component (rubber polymer) in the latex is not particularly limited, but generally 10 to 70% by mass can be used. Specific examples of the rubber component include natural rubber (NR), polyisoprene rubber (IR), styrene butadiene rubber (SBR), polybutadiene rubber (BR), nitrile rubber (NBR), chloroprene rubber (CR), butyl rubber ( IIR) and other diene rubbers may be mentioned, and these may be used alone or in combination of two or more. Preferably, NR, IR, SBR, BR, or a blend rubber of two or more of these is used.

  The mixing method of the water suspension containing the fibrillated cellulose fiber and the water-soluble cellulose derivative and the rubber latex is not particularly limited. For example, a known mixer such as a homogenizer, a propeller type stirring device, or a rotary type stirring device is used. Can be done.

  The method of obtaining the rubber master batch by drying the liquid mixture thus obtained is not particularly limited, and water is removed from the liquid mixture by a general method such as spray drying, natural drying, oven drying, freeze drying and the like. do it. Preferably, it is spray-dried, and a rubber / cellulose masterbatch can be prepared with the water-soluble cellulose derivative adsorbed well on the surface of the fibrillated cellulose fiber. The dispersibility of the fibrillated cellulose fiber in the rubber , Adhesion can be further improved. Spray drying can be performed using a known spray drying apparatus. Examples of the spray drying method include a nozzle type and a disk type, and a nozzle type spray dryer is preferable. As drying temperature, it is preferable that it is 100 degreeC or more, More preferably, it is 120 degreeC or more. Although the upper limit of drying temperature is not specifically limited, Usually, it is 200 degrees C or less.

  In the rubber / cellulose master batch of the present embodiment thus obtained, the mixing ratio of the fibrillated cellulose fiber and the rubber component is not particularly limited, but the fibrillated cellulose with respect to 100 parts by mass of the rubber component (solid content). It is preferable that a fiber is 0.5-100 mass parts, More preferably, it is 1-50 mass parts, More preferably, it is 5-30 mass parts. By setting it as such a compounding quantity, the outstanding reinforcement effect by a fibrillated cellulose fiber can be exhibited more effectively.

  In the rubber / cellulose masterbatch, the amount of the water-soluble cellulose derivative is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 25 parts by mass with respect to 100 parts by mass of the fibrillated cellulose fiber. Part, more preferably 1 to 10 parts by mass. By setting it as such a compounding quantity, rigidity can be improved, suppressing the deterioration of low exothermic property.

  The rubber composition according to the present embodiment includes the rubber / cellulose master batch (hereinafter sometimes simply referred to as a master batch). As described above, in the masterbatch, the fibrillated cellulose fiber has a water-soluble cellulose derivative adsorbed on the fiber surface, that is, includes a fibrillated cellulose fiber surface-treated with the water-soluble cellulose derivative. Therefore, the rubber composition contains fibrillated cellulose fibers surface-treated with a water-soluble cellulose derivative.

  In the rubber composition, the rubber component may be composed only of the rubber polymer derived from the master batch, but apart from the one blended from the master batch, a normal natural rubber or a diene synthetic rubber ( For example, it may contain any one or more of various rubber polymers such as IR, BR, SBR, CR, NBR, IIR and the like. The rubber component derived from the master batch with respect to the entire rubber component in the rubber composition is preferably 30% by mass or more, and more preferably 50% by mass or more.

  Moreover, content of the said fibrillated cellulose fiber in a rubber composition is not specifically limited, What is necessary is just to set suitably so that the reinforcement property requested | required according to the use of a rubber composition may be exhibited. Preferably, the content of fibrillated cellulose fiber is 0.1 to 50 parts by weight, more preferably 1 to 40 parts by weight, and still more preferably 100 parts by weight of the total rubber component contained in the rubber composition. 5 to 30 parts by mass.

A reinforcing filler such as silica or carbon black can be appropriately added to the rubber composition according to the purpose at the time of rubber kneading. Examples of the silica include wet silica and dry silica, but wet silica is preferable. Although the specific surface area of a silica is not specifically limited, It is preferable that a nitrogen adsorption specific surface area is 100-300 m < ² > / g, More preferably, it is 150-250 m < ² > / g. Here, the nitrogen adsorption specific surface area is measured according to the BET method described in ISO 5794. Further, as the carbon black, various grades such as SAF, ISAF, HAF, FEF, GPF, and SRF can be used depending on the application. Although the compounding quantity of these silica and / or carbon black is not specifically limited, It is preferable that it is 20-100 mass parts with respect to 100 mass parts of rubber components, More preferably, it is 30-80 mass parts.

  The rubber composition is also blended with various additives generally used in the rubber industry, such as softeners, plasticizers, anti-aging agents, zinc white, stearic acid, resins, vulcanizing agents, and vulcanization accelerators. be able to. Examples of the vulcanizing agent include sulfur, a sulfur-containing compound, and the like, and are not particularly limited. However, the blending amount is 0.1 to 10 parts by mass with respect to 100 parts by mass of all rubber components in the rubber composition. It is preferable that it is 0.5-5 mass parts. Moreover, as a compounding quantity of a vulcanization accelerator, it is preferable that it is 0.1-7 mass parts with respect to 100 mass parts of all the rubber components in a rubber composition, More preferably, it is 0.5-5 mass parts. is there.

  The rubber composition can be produced by adding an additive to the master batch and kneading according to a conventional method using a commonly used mixer such as a Banbury mixer, a kneader, or a roll. More specifically, in the first mixing stage (NP), the master batch, optionally other rubber components, and chemicals excluding vulcanizing additives such as vulcanizing agents and vulcanization accelerators are kneaded. Then, in the subsequent second mixing stage (FN), the rubber composition can be prepared by adding and mixing the vulcanizing additive to the kneaded product obtained above.

  The rubber composition thus obtained is vulcanized and molded at 140 to 200 ° C. according to a conventional method, for example, tires such as treads, sidewalls, bead fillers, rim strips, conveyor belts, vibration-proof rubbers, etc. It can be used for various applications. Preferably, the rubber composition can be used as a rubber member of a pneumatic tire because it can enhance the reinforcement while suppressing deterioration of low heat build-up, and the reinforcement and low fuel consumption required for the tire. The balance can be improved.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Preparation of master batch>
[Example 1]
Fine powdered cellulose (“KC Flock W-400G” manufactured by Nippon Paper Chemical Co., Ltd.) is used as the cellulose fiber, and methylcellulose (“Methylcellulose 1500 cP” manufactured by Wako Pure Chemical Industries, Ltd.), degree of etherification: 0.78 is used as the water-soluble cellulose derivative. ~ 0.99) was used. 20 parts by mass of cellulose fiber and 0.5 parts by mass of a water-soluble cellulose derivative are mixed and stirred with 980 parts by mass of water to prepare an aqueous suspension (slurry). A grinding process was performed. The grinding treatment was performed using “Supermass colloider MKCA6-2” (abrasive plate: MKG, abrasive grain size: No. 120) manufactured by Masuko Sangyo Co., Ltd., with the clearance of the abrasive plate: 0 μm (contact operation), abrasive The rotation speed of the granule plate was set to 1500 rpm, and the number of passes was set to 5 times, and the aqueous suspension was passed through the sliding portion of the apparatus. Thereby, an aqueous suspension containing fibrillated cellulose fibers (MFC) and methylcellulose (MC) was obtained. The average fiber diameter of the fibrillated cellulose fibers after the grinding treatment was 15 nm.

  The water suspension after the grinding treatment and the styrene butadiene rubber latex (“SB Latex Nipol LX110” manufactured by Nippon Zeon Co., Ltd., solid content concentration = 40.5% by mass) with respect to 100 parts by mass of the rubber component (SBR) Then, the mixture is stirred and mixed using a homogenizer so that the fibrillated cellulose fiber (MFC) becomes 20 parts by mass, and the obtained mixed solution is put into a spray drying apparatus (“Spray dryer ADL311S-A” manufactured by Yamato Scientific Co., Ltd.). The rubber / cellulose master batch A was obtained by spray drying at a drying temperature (nozzle temperature) = 160 ° C.

[Example 2]
When mixing the cellulose fiber and the water-soluble cellulose derivative, 20 parts by mass of the cellulose fiber and 1 part by mass of the water-soluble cellulose derivative are mixed with 980 parts by mass of water. Got. The average fiber diameter of the fibrillated cellulose fiber after the grinding treatment was 12 nm.

[Example 3]
When mixing the cellulose fiber and the water-soluble cellulose derivative, 20 parts by mass of the cellulose fiber and 5 parts by mass of the water-soluble cellulose derivative are mixed with 980 parts by mass of water. Got. The average fiber diameter of the fibrillated cellulose fibers after the grinding treatment was 15 nm.

[Example 4]
As the water-soluble cellulose derivative, hydroxypropyl methylcellulose (HPMC, “Metrozu 65SH” manufactured by Shin-Etsu Chemical Co., Ltd., degree of etherification: 1.8) was used in place of methylcellulose. Cellulose masterbatch D was obtained. The average fiber diameter of the fibrillated cellulose fiber after the grinding treatment was 18 nm.

[Comparative Example 1]
20 parts by weight of finely powdered cellulose (“KC Flock W-400G” manufactured by Nippon Paper Chemical Co., Ltd.) is added to 980 parts by weight of water and stirred to prepare an aqueous suspension (slurry). On the other hand, the same grinding treatment as in Example 1 was performed to obtain an aqueous suspension containing fibrillated cellulose fibers (MFC). The average fiber diameter of the fibrillated cellulose fiber after the grinding treatment was 20 nm. The obtained water suspension and styrene butadiene rubber latex (“SB Latex Nipol LX110” manufactured by Zeon Corporation, solid content = 40.5 mass%) are fibrillated with respect to 100 parts by mass of the rubber component (SBR). A rubber / cellulose master batch E was obtained by spray-drying the resulting mixed solution in the same manner as in Example 1 with stirring and mixing using a homogenizer so that the modified cellulose fiber (MFC) was 20 parts by mass. .

[Comparative Example 2]
In place of the water-soluble cellulose derivative, polyethylene oxide (PEO, “Polyethylene oxide 200000” manufactured by Wako Pure Chemical Industries, Ltd.) was used as the water-soluble polymer, and the rubber / cellulose master batch F was obtained in the same manner as in Example 1. It was. The average fiber diameter of the fibrillated cellulose fiber after the grinding treatment was 18 nm.

[Comparative Example 3]
After grinding treatment in the same manner as in Comparative Example 1, methylcellulose (“Methylcellulose 1500 cP” manufactured by Wako Pure Chemical Industries, Ltd.) was added to the resulting aqueous suspension, and the blending amount thereof was 20 mass of fibrillated cellulose fibers. It added so that it might become 1 mass part with respect to a part, and mixed and stirred. Thereafter, in the same manner as in Example 1, it was mixed with a styrene butadiene rubber latex and further spray-dried to obtain a rubber / cellulose master batch G.

<Preparation and evaluation of rubber composition>
According to the blending (parts by mass) shown in Table 1 below, first, in the first mixing stage, the blending components excluding sulfur and the vulcanization accelerator are kneaded for 5 minutes using a lab mixer (labor plast mill), and then The resulting kneaded product was added with sulfur as a vulcanizing agent and a vulcanization accelerator at the final mixing stage and mixed for 1 minute to obtain a rubber composition. The details of each component in Table 1 are as follows.

SBR: styrene butadiene rubber obtained by spray-drying “SB Latex Nipol LX110” manufactured by Nippon Zeon Co., Ltd. Silica: “Ultrasil VN3” manufactured by Degussa, BET specific surface area = 175 m ² / g
・ Zinc oxide: “Zinc Hana 3” manufactured by Mitsui Mining & Smelting Co., Ltd.
・ Stearic acid: “Lunac S-20” manufactured by Kao Corporation
Silane coupling agent: “Si75” manufactured by Degussa
・ Sulfur: “Powder sulfur” manufactured by Tsurumi Chemical Co., Ltd.
・ Vulcanization accelerator CZ: “Soccinol CZ” manufactured by Sumitomo Chemical Co., Ltd.
・ Vulcanization accelerator D: “Noxeller D” manufactured by Ouchi Shinsei Chemical Co., Ltd.

Each rubber composition obtained was molded into a predetermined shape and then vulcanized at 160 ° C. for 30 minutes in a mold to prepare a test piece. Using the obtained test pieces, the breaking strength TB, the elongation at break EB, the complex elastic modulus E ^* as a reinforcement index, and the loss coefficient tan δ as a low heat generation index were measured. The measuring method is as follows.

TB, EB: Breaking strength and elongation at break were measured by a tensile test according to JIS K6251 (Dumbell-shaped No. 3 type), and displayed as an index with the value of Comparative Example 4 being 100. The larger the index, the greater the breaking strength and elongation at break.

E ^* , tan δ: According to JIS K6394, a viscoelasticity measurement test is performed under the conditions of a temperature of 23 ° C., a frequency of 10 Hz, a dynamic strain of 2%, and a static strain of 5% to obtain a complex elastic modulus E ^* and a loss coefficient tan δ. In each case, the value of Comparative Example 4 was expressed as an index of 100. The larger the E ^* index, the higher the reinforcement and the higher the rigidity, and the lower the tan δ index, the smaller the energy loss, and thus the less heat is generated, and the lower the heat generation (low fuel consumption). It shows that.

  The results are as shown in Table 1. In Comparative Example 4, the masterbatch containing fibrillated cellulose fibers was blended, so that the rigidity was higher than that of Comparative Example 6 and the low heat build-up was improved. In Examples 5 to 8, by adding a masterbatch containing fibrillated cellulose fibers surface-treated with a water-soluble cellulose derivative, higher rigidity was achieved with respect to Comparative Example 4, and mechanical properties were also excellent. At the same time, the low heat build-up was improved and the balance between them was excellent. On the other hand, in Comparative Example 5 using PEO having the same hydrogen bonding ability instead of the water-soluble cellulose derivative, although performance improvement was seen with respect to Comparative Example 6, as in Examples 5-8 There was no significant performance improvement. Thus, no significant performance improvement can be seen only by having a hydrogen bonding ability, and the water-soluble cellulose derivative having a cellulose molecular skeleton effectively adsorbs on the surface of the fibrillated cellulose fiber and inhibits the aggregation of the fibrillated cellulose fiber. Thus, it is considered that the dispersibility with respect to the rubber component and the adhesion between the rubber component are improved, and thereby significant performance improvement is obtained in high rigidity and mechanical characteristics and low heat generation. Moreover, in Comparative Example 7, since the water-soluble cellulose derivative was added after the grinding treatment of the cellulose fiber, compared with Examples 5 to 8, the effect of achieving both high rigidity and low exothermicity was inferior.

Claims (6)

  Applying mechanical shearing force to an aqueous suspension containing cellulose fiber and a water-soluble cellulose derivative to fibrillate the cellulose fiber, mixing the obtained aqueous suspension and rubber latex, and drying the mixture A process for producing a rubber / cellulose masterbatch characterized by   The method for producing a rubber / cellulose masterbatch according to claim 1, wherein the water-soluble cellulose derivative is at least one selected from the group consisting of alkylcellulose, hydroxyalkylcellulose and hydroxyalkylalkylcellulose.   The method for producing a rubber / cellulose masterbatch according to claim 1 or 2, wherein the amount of the fibrillated cellulose fiber is 1 to 50 parts by mass with respect to 100 parts by mass of the rubber component in the rubber latex. .   The amount of the water-soluble cellulose derivative is 0.1 to 25 parts by mass with respect to 100 parts by mass of the fibrillated cellulose fiber. A method for producing a cellulose masterbatch.   A rubber / cellulose masterbatch produced by the method according to claim 1.   The rubber composition which mix | blended the rubber / cellulose masterbatch manufactured with the method of any one of Claims 1-4.