JP5614372B2 - Rubber composition for tire - Google Patents

Description

  The present invention relates to a rubber composition for tires, and more specifically, improves the vulcanization speed of a rubber composition containing silica, enables improvement of modulus of vulcanized rubber, reduction of rolling resistance, and weight reduction of tire, Relates to a rubber composition for tires using environmentally friendly materials.

  Recently, silica tends to be used as a filler in tire rubber compositions, particularly in tread rubber compositions for pneumatic tires (Non-Patent Document 1: Journal of Adhesion Society of Japan, Vol. 37, No. 37, page 197). Silica can reduce rolling resistance compared to carbon black, but there is a problem that rolling resistance deteriorates when the amount of silica is further increased in order to increase the modulus and the like. Moreover, when the compounding quantity of a silica increases, there exists a problem of acting on the direction which a vulcanization | cure speed | rate becomes late | slow and worsening productivity.

  Therefore, in Patent Documents 1 and 2 (Japanese Patent Laid-Open Nos. 2008-308615 and 2010-248282), the improvement is achieved by blending a lignin sulfonate or a modified product thereof into a silica-blended tire. However, the vulcanization rate was slow and suitable for weight reduction, but the tire strength tended to be slightly weakened.

On the other hand, due to increasing environmental problems such as global warming and fossil fuel depletion, it is an urgent need to actively use biomass materials instead of petroleum-derived materials. There are also movements such as producing biomass fuel (for example, bioethanol) from bamboo and forest thinning. At this time, when biomass fuel is extracted, a large amount of residue called “lignocellulose” is obtained, but no effective utilization method has been found so far.
The “lignocellulose” referred to here is a generic name for lignin, cellulose and the like which are wood components.

JP 2008-308615 A JP 2010-248282 A

Journal of the Adhesion Society of Japan Vol. 37, No. 5, 197

  The present invention has been made in view of the above circumstances, improves the vulcanization speed of the rubber composition compounded with silica, enables improvement of the modulus of the vulcanized rubber, reduction of rolling resistance and weight reduction of the tire, An object of the present invention is to provide a rubber composition for tires using environmentally friendly materials.

  As a result of researches to solve the above problems, the present inventor improves the modulus of rubber and reduces rolling resistance by blending silicone-modified lignocellulose with a rubber composition containing diene rubber and silica. A rubber composition that can be obtained was obtained, and the productivity was improved by increasing the vulcanization rate of the rubber composition, and the present invention was achieved. This is probably because the compatibility between the filler and the rubber could be improved.

Accordingly, the present invention provides the following rubber composition for tires.
Claim 1:
Including 100 parts by mass of diene rubber, 10 to 100 parts by mass of silica , and 1 to 30 parts by mass of silicone-modified lignocellulose in which silane or silicone compound is chemically adsorbed after low-temperature plasma treatment at 20 to 300 ° C. A rubber composition for tires, characterized in that
Claim 2 :
The tire rubber composition according to claim 1, wherein the silane or the silicone compound is Si-H group-containing compound.
Claim 3 :
3. The tire use according to claim 1, wherein the silicone-modified lignocellulose is obtained by performing chemical adsorption treatment with a silane coupling agent containing a sulfur atom after chemically adsorbing silane or a silicone compound. Rubber composition.
Claim 4 :
The tire rubber composition according to any one of claims 1 to 3 , wherein the low-temperature plasma is water vapor, oxygen, or ammonia plasma.

  According to the present invention, by adding silicone-modified lignocellulose to a rubber composition containing silica, the vulcanization speed of the rubber composition is improved, the modulus of the vulcanized rubber is improved, the rolling resistance is reduced, and the tire It is possible to reduce the weight of lignocellulose, and it leads to the effective use of lignocellulose, a biomass material residue that is an environmentally friendly material.

  The rubber composition of the present invention is a tire rubber composition containing diene rubber, silica, and silicone-modified lignocellulose.

  In the present invention, 10 to 100 parts by mass of silica, preferably 20 to 90 parts by mass, and 1 to 30 parts by mass, preferably 5 to 25 parts by mass of silicone-modified lignocellulose, per 100 parts by mass of the diene rubber. Blend. If the blending amount of silica is small, the reinforcing property of the rubber becomes insufficient. Conversely, if the silica content is large, the mixing processability deteriorates and the rolling resistance also deteriorates. On the other hand, when the blending amount of the silicone-modified lignocellulose is small, the vulcanization speed is slow, and conversely when it is large, the balance between rolling resistance and modulus is lost.

<Diene rubber>
Here, the diene rubber used in the present invention may be any rubber that can be used for tires, such as natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer. Combined rubber (SBR), various modified butyl rubbers, ethylene-propylene rubber (EPDM) and the like can be used singly or in an arbitrary blend of two or more.

<Silica>
There is no restriction | limiting in particular in the silica which can be used in this invention, Arbitrary silica which can be used for tires can be used. However, BET specific a surface area of 180 m ² / g or less of silica is preferably measured at ASTM D1993-03, more preferably by using a silica 20~178m ² / g, it is possible to further reduce the rolling resistance. Commercially available silica can be used as such silica, and examples include Zeosil 165GR manufactured by Rhodia Co., Ltd., and Nippon Sil ER manufactured by Tosoh Silica.

<Silicone-modified lignocellulose>
According to the present invention, by adding silicone-modified lignocellulose to a silica-based compound, the modulus of the vulcanization compound is improved, the rolling resistance is reduced, and the vulcanization speed of the compound is slowed by the silica compounding. The effect of speeding up the tire and the weight reduction of the tire are achieved.

Here, the silicone-modified lignocellulose used in the present invention will be described.
Lignocellulose used for silicone-modified lignocellulose is a general term for what is obtained as a residue when biomass fuel is extracted, and contains cellulose and / or lignin as wood components. As the content, since cellulose is used for biomass, it becomes lignin-rich. The shape is a brown to brown powder. However, the present invention is not limited to this, and lignin powder extracted from waste wood may be used.
The average particle size of lignocellulose is preferably from 0.01 to 100 μm, more preferably from 0.1 to 80 μm, particularly preferably from 1 to 50 μm.

The silicone-modified lignocellulose is preferably subjected to low-temperature plasma treatment using the above lignocellulose.
Plasma means a state in which a gas is ionized. In the plasma, positive and negative charged particles fly around at high speed, and a large Coulomb force acts between the charged particles, so that the kinetic energy of the particles increases. For this reason, due to the presence of atoms and molecules that are disconnected by high-energy particles, plasma-ized water vapor and oxygen have a very strong oxidizing power and reducing power. By performing this plasma treatment, hydroxyl groups, carboxyl groups and the like are introduced to the lignocellulose surface, so that the following silicone treatment can be performed more effectively.

  Such plasma is not limited by its generation method or generator, but is preferably water vapor plasma, oxygen plasma or ammonia plasma generated by high frequency induction heating, and the high frequency output is 10 to 500 kW, 20 to 200 kW is particularly preferable for supplying stable plasma. The frequency is preferably 10 to 20 kHz, and the pressure is preferably 0.01 to 10 Torr.

  Moreover, the temperature of the said plasma has the preferable range of 20-300 degreeC from a viewpoint of the versatility of a process, and an energy cost, More preferably, it is 20-250 degreeC, More preferably, it is 25-150 degreeC. The plasma treatment time is preferably 20 to 360 minutes, particularly preferably 30 to 120 minutes.

  It is preferable that the surface is treated by chemically adsorbing silane or silicone on the above-obtained lignocellulose subjected to the low temperature plasma treatment. There are no particular limitations on the silane or silicone used in the treatment, but Si-H group-containing silane compounds or Si-H group-containing silicone (siloxane) compounds are particularly preferred. The Si—H group-containing silane or silicone compound used in the present invention is not particularly limited as long as it contains one or more Si—H groups, but the following general formulas (1), (2) and What is shown by (3) is preferable.

(H) _n SiR _(4-n) (1)
(In the formula, R is the same or different alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and n = 1, 2, or 3).

  Here, R in the formula (1) is the same or different alkyl group having 1 to 20 carbon atoms, particularly 1 to 10 carbon atoms, or alkoxy group having 1 to 4 carbon atoms, specifically a methyl group, an ethyl group, Examples include propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, methoxy group, ethoxy group, propoxy group, isopropoxy group and the like. Examples of such silane compounds include the following.

HSi (CH ₃ ) ₃ ,
H ₂ Si (CH ₃ ) ₂ ,
H ₃ Si (CH ₃ ),
SiH ₄ ,
HSi (CH ₂ CH ₃ ) ₃ ,
H ₂ Si (CH ₂ CH ₃ ) ₂ ,
H ₃ Si (CHCH ₃ ),
HSi (OCH ₃ ) ₃ ,
H ₂ Si (OCH ₃ ) ₂ ,
H ₃ Si (OCH ₃ ),
HSi (OCH ₂ CH ₃ ) ₃ ,
H ₂ Si (OCH ₂ CH ₃ ) ₂ ,
H ₃ Si (OCH ₂ CH ₃ )
Among them, HSi (OCH ₃ ) ₃ and HSi (OCH ₂ CH ₃ ) are preferable.

（式中、Ｒ¹は水素原子、同一もしくは異種の炭素数１〜２０のアルキル基、又は炭素数６〜２０のアリール基である。）

(In the formula, R ¹ is a hydrogen atom, the same or different alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.)

Here, R ¹ in the formula (2) is independently a hydrogen atom, the same or different alkyl group having 1 to 20 carbon atoms, particularly 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, particularly 6 to 12 carbon atoms. Yes, specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, cyclopentyl group , A cyclohexyl group, a cycloheptyl group, a phenyl group, a tolyl group, a naphthyl group, and the like, and a methyl group is preferable. Specific examples of such a siloxane compound include the following.

である。 Of these, preferably

It is.

（式中、Ｒ¹は上記と同じ、Ｘはそれぞれ独立に水素原子、同一もしくは異種の炭素数１〜２０のアルキル基、炭素数６〜２０のアリール基、炭素数１〜２０のアルコキシ基、又はヒドロキシル基、Ｙはそれぞれ独立にＸ又は−［Ｏ−Ｓｉ（Ｘ）₂］_c−Ｘで示される同一又は異種の基、ａは０〜１，０００の整数、ｂは０〜１，０００の整数、ｃは１〜１，０００の整数であり、分子中にＨ−Ｓｉ基を１個以上含有する。）

(Wherein R ¹ is the same as above, X is independently a hydrogen atom, the same or different alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, Or a hydroxyl group, Y is independently the same or different group represented by X or — [O—Si (X) ₂ ] _c —X, a is an integer of 0 to 1,000, and b is 0 to 1,000. And c is an integer of 1 to 1,000 and contains at least one H-Si group in the molecule.)

Here, R ¹ in formula (3) is the same as defined in formula (2). X is independently a hydrogen atom, the same or different alkyl group having 1 to 20 carbon atoms, particularly 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, particularly 6 to 12 carbon atoms, 1 to 20 carbon atoms, particularly 1 to 4 carbon atoms. Alkoxy group, or hydroxyl group, specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, Hexadecyl, octadecyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl, tolyl, naphthyl, methoxy, ethoxy, propoxy, butoxy, hexyloxy, heptyloxy, octyloxy, decyloxy Group, tetradecyloxy group and the like.

It is preferable that at least one of the three Xs at both ends is H. Y is independently the same or different group represented by X or — [O—Si (X) ₂ ] _c —X, and when a is greater than 1,000, the resulting lignocellulose has poor permeability. Since there are cases, it is an integer of 0 to 1,000, preferably an integer of 0 to 200. Moreover, since the permeability to lignocellulose to be obtained may deteriorate when b is larger, it is an integer of 0 to 1,000, preferably an integer of 0 to 200. c is an integer of 1 to 1,000, particularly 1 to 500.

Specific examples of such silicone compounds include the following.

（ａ，ｂ，ｃは上記の通り。）

(A, b, and c are as described above.)

  When these Si—H group-containing silanes or silicone compounds are treated with low-temperature plasma-treated lignocellulose, a method of chemical adsorption in the gas phase is more preferred. In the temperature range of 20 to 300 ° C., particularly 20 to 200 ° C., it is preferable to contact the Si—H group-containing silane or silicone compound vaporized by decompression. The reaction time is preferably 1 to 48 hours, more preferably 2 to 24 hours.

  The treatment amount of the Si-H group-containing silane or silicone compound is preferably treated in the range of 0.3 to 15% by mass with respect to the low-temperature plasma-treated lignocellulose. More preferably, it is 2-10 mass%. When the treatment amount of the Si—H group-containing silane or silicone compound is less than 0.3% by mass, the effect of improving the modulus of the compound and the effect of reducing the rolling resistance cannot be obtained, and the mixing property may be deteriorated. On the contrary, even if the amount exceeding 15% by mass is processed, no further improvement is observed, which may be disadvantageous in cost.

  In order to make the Si-H group-containing compound react more strongly after the treatment, ammonia vapor or the like may be contact-treated.

This may be used as a constituent as it is, but may further be treated with a sulfur atom-containing silane coupling agent as shown in the following general formula (4).
(R ² ) _d (R ³ ) _e Si-A (4)
Wherein R ² is an alkoxy group having 1 to ³ carbon atoms, R ³ is an alkyl group, alkenyl group or alkyl polyether group having 1 to 40 carbon atoms, A is a functional group containing a sulfur atom, and d is 1 to 3 D + e = 3.)

The sulfur atom-containing silane coupling agent represented by the general formula (4) comprises an R ² group capable of reacting with a hydroxyl group in lignocellulose and a functional group A containing a sulfur atom capable of reacting with a diene rubber. Thus, by treating lignocellulose with this, the vulcanization rate can be improved or the reinforcement can be improved.

In Formula (4), R ² includes a methoxy group, an ethoxy group, a propoxy group, and an isopropoxy group, and more preferably a methoxy group or an ethoxy group. R ³ is an alkyl group, alkenyl group or alkyl polyether group having 1 to 40 carbon atoms, particularly 1 to 20 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t- Examples thereof include alkyl groups such as butyl group, hexyl group, octyl group, nonyl group and decyl group, and alkenyl groups such as vinyl group and allyl group. R ³ is preferably an alkyl group having 1 to 4 carbon atoms or an alkenyl group, and more preferably an alkyl group having 1 to 4 carbon atoms. For R ³ , the alkyl polyether group is —O— (R ^a —O) _k —R ^b (where R ^a is an alkylene group having 1 to 4 carbon atoms, R ^b is 1 to 16 carbon atoms, In particular, the alkyl group is 1 to 8, and k is preferably 1 to 20, particularly 1 to 15. Examples of R ^a include a methylene group, ethylene group, propylene group, butylene group, and examples of R ^b include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkyl polyether group include —O— (CH ₂ CH ₂ —O) ₅ — (CH ₂ ) ₁₀ CH ₃ , —O— (CH ₂ CH ₂ —O) ₅ — (CH ₂ ) ₁₁ CH ₃ , — O— (CH ₂ CH ₂ —O) ₅ — (CH ₂ ) ₁₂ CH ₃ , —O— (CH ₂ CH ₂ —O) ₅ — (CH ₂ ) ₁₃ CH ₃ , —O— (CH ₂ CH ₂ — O) ₅ — (CH ₂ ) ₁₄ CH ₃ , —O— (CH ₂ CH ₂ —O) ₃ — (CH ₂ ) ₁₂ CH ₃ , —O— (CH ₂ CH ₂ —O) ₄ — (CH ₂ ) ₁₂ CH ₃ , —O— (CH ₂ CH ₂ —O) ₆ — (CH ₂ ) ₁₂ CH ₃ , —O— (CH ₂ CH ₂ —O) ₇ — (CH ₂ ) ₁₂ CH _{3 and the} like.

Moreover, as a functional group A in Formula (4), the following general formula (5)-(7) is mentioned as a preferable thing.
—R ⁴ —S _x —R ⁵ —Si (R ² ) _c (R ³ ) _d (5)
-R ⁶ -SH (6)
^{-R 7 -S-CO-R 8} (7)

In the formula, R ⁴ and R ⁵ are each independently an alkylene group having 1 to 8 carbon atoms, more preferably an alkylene group having 2 to 4 carbon atoms, such as a methylene group, an ethylene group, a propylene group, And a butylene group. R ⁶ is an alkylene group having 1 to 16 carbon atoms, and more preferably an alkylene group having 2 to 4 carbon atoms. R ⁷ is an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 2 to 4 carbon atoms, and examples thereof include a methylene group, an ethylene group, a propylene group, and a butylene group. R ⁸ is an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 5 to 9 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group. . x is 2 to 8, more preferably 2 to 4. In addition, x has a normal distribution, that is, it is generally marketed as a mixture having different numbers of sulfur chain bonds, and x represents an average value thereof. R ² , R ³ , c, and d are the same as defined in the above formula (3).

  Examples of the sulfide silane coupling agent in which the functional group A is represented by the above formula (5) include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, and bis (2- Triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) disulfide and the like are preferable.

Examples of the mercaptosilane coupling agent in which the functional group A is represented by the above formula (6) include γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, mercaptopropylmethyldimethoxysilane, and mercaptopropyldimethylmethoxysilane. , Mercaptoethyltriethoxysilane, and VP Si363 (R ² : —OC ₂ H ₅ , R ³ : —O (C ₂ H ₄ O) _k —C ₁₃ H ₂₇ , R ⁶ : — (CH _{2 3} ), c = average 1, d = average 2, k = average 5) and the like are preferable.

  Preferred examples of the protected mercaptosilane coupling agent in which the functional group A is represented by the above formula (7) include 3-octanoylthio-1-propyltriethoxysilane, 3-propionylthiopropyltrimethoxysilane, and the like. It is done.

  When the above sulfur atom-containing silane coupling agent is treated with silicone-modified lignocellulose, a method of chemical adsorption in the gas phase is more preferable. In a temperature range of 20 to 300 ° C., particularly 20 to 200 ° C., it is preferable to contact with a sulfur atom-containing silane coupling agent vaporized by reduced pressure. The reaction time is preferably 1 to 48 hours, more preferably 2 to 24 hours, still more preferably 5 to 20 hours. The processing amount of the sulfur atom-containing silane coupling agent is preferably 0.5 to 15% by mass with respect to the silicone-modified lignocellulose. More preferably, it is 2-10 mass%. If the treatment amount of the sulfur atom-containing silane coupling agent is less than 0.5% by mass, sufficient reinforcement and vulcanization rate may not be obtained. Conversely, the amount exceeding 15% by mass. Even if it treats, the further improvement of reinforcement property is not seen, but low exothermic property may be impaired on the contrary.

  In addition to the components described above, the rubber composition according to the present invention includes other reinforcing agents (fillers) such as carbon black, vulcanization or crosslinking agents, vulcanization or crosslinking accelerators, various oils, anti-aging agents, plastics Various additives that are generally blended for tires such as additives, and other rubber compositions can be blended, and such additives are kneaded by a general method to form a composition, which is then vulcanized or crosslinked. Can be used to do. As long as the amount of these additives is not contrary to the object of the present invention, a conventional general amount can be used.

  The rubber composition of the present invention can be obtained by kneading each of the above components at 100 to 200 ° C. for 1 to 120 minutes by a conventional method, and sulfur is added thereto and heated at 50 to 150 ° C. for 1 to 60 minutes. Thus, a vulcanized rubber can be obtained.

  Hereinafter, the present invention will be specifically described with reference to production examples, examples, and comparative examples. The following examples do not limit the present invention.

<Production Example 1>
[Preparation of silicone-modified lignocellulose (1)]
Pre-dried lignocellulose powder (biofuel residue, brown powder, average particle size 30 μm) is set in a reaction vessel, adjusted to a high frequency output of 45 W, a frequency of 13.56 kHz, a pressure of 0.6 Torr, and a plasma temperature. Was set at 25 ° C. and oxygen gas was supplied for 70 minutes.

The lignocellulose powder subjected to plasma treatment was taken out, 1,3,5,7-tetramethylcyclotetrasiloxane was introduced under reduced pressure (100 mmHg), vaporized at 30 ° C., and subjected to gas phase treatment for 12 hours. . Thereafter, deaeration treatment was performed to remove unreacted silane, and ammonia gas was introduced into the silane for further reaction to obtain silicone-modified lignocellulose (1).
The amount of siloxane treated was 15% by mass.

<Production Example 2>
[Preparation of silicone-modified lignocellulose (2)]
A silicone-modified lignocellulose (2) was obtained in the same manner as in Production Example 1 except that the oxygen gas in Production Example 1 was replaced with water vapor. The amount of siloxane treated was 11% by mass.

<Production Example 3>
[Preparation of silicone-modified lignocellulose (3)]
A silicone-modified lignocellulose (3) was obtained in the same manner as in Production Example 1 except that the oxygen gas in Production Example 1 was replaced with ammonia. The amount of siloxane treated was 15% by mass.

<Production Example 4>
[Preparation of silicone-modified lignocellulose (4)]
Pre-dried lignocellulose powder (biofuel residue, brown powder, average particle size 30 μm) is set in a reaction vessel, adjusted to a high frequency output of 45 W, a frequency of 13.56 kHz, a pressure of 0.6 Torr, and a plasma temperature. Was set at 25 ° C. and oxygen gas was supplied for 70 minutes.

The lignocellulose powder subjected to plasma treatment was taken out, 1,3,5,7-tetramethylcyclotetrasiloxane was introduced under reduced pressure (100 mmHg), vaporized at 30 ° C., and subjected to gas phase treatment for 12 hours. . Thereafter, deaeration treatment was performed to remove unreacted silane, and ammonia gas was introduced into the silane for further reaction. The amount of siloxane treated was 15% by mass.
After that, under reduced pressure (5 mmHg), γ-mercaptopropyltrimethoxysilane was introduced at 200 ° C., gas phase treatment was performed, then degassing treatment was performed to remove unreacted silane, and ammonia gas was introduced there. Further reaction was performed. The amount of γ-mercaptopropyltrimethoxysilane treated was 5% by mass.

<Production Example 5>
[Preparation of silicone-modified lignocellulose (5)]
The same treatment was carried out except that γ-mercaptopropyltrimethoxysilane in Production Example 4 was replaced with bis (3-triethoxysilylpropyl) disulfide. The throughput of bis (3-triethoxysilylpropyl) disulfide was 3% by mass.

<Examples 1-8 and Comparative Examples 1-4>
Sample preparation In the formulations shown in Tables 1 and 2, the components other than the vulcanization accelerator and sulfur were kneaded with a 1.8 liter closed mixer for 5 minutes and released when the temperature reached 150 ° C to obtain a master batch. It was. A vulcanization accelerator and sulfur were kneaded with this master batch with an open roll to obtain a rubber composition. Using this rubber composition, unvulcanized physical properties were evaluated by the following test methods. The results are shown in Tables 1 and 2 as index values with the value of Comparative Example 1 being 100.

  Next, the resulting rubber composition was vulcanized in a 15 × 15 × 0.2 cm mold at 160 ° C. for 20 minutes to prepare a vulcanized rubber sheet. The physical properties of the vulcanized rubber were measured by the following test methods. It was measured. The results are shown in Tables 1 and 2 as index values with the value of Comparative Example 1 being 100.

(Rubber property evaluation test method)
Vulcanization rate: T95 (time to reach a vulcanization degree of 95% at 160 ° C.) was measured with a rheometer in accordance with JIS K6300-2. The smaller this value, the faster and better the vulcanization rate.

  300% modulus: evaluated by a tensile test according to JIS K6251. A larger value indicates better.

  Wet performance (0 ° C. tan δ) and rolling resistance (60 ° C. tan δ): Loss tangent (tan δ) at 0 ° C. and 60 ° C. was measured according to JIS K6394. The measurement was carried out using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho Co., Ltd. under the conditions of an initial strain of 10%, an amplitude of ± 2%, and a frequency of 20 Hz. The larger the value of 0 ° C. tan δ, the better the wet performance, and the smaller the value of 60 ° C. tan δ, the better the rolling resistance.

(note)
* 1: Natural rubber (TSR-20)
* 2: Nipol 1502 manufactured by Nippon Zeon Co., Ltd.
* 3: Seast N made by Tokai Carbon Co., Ltd.
* 4: Zeosil 165GR manufactured by Rhodia Co., Ltd. (BET = 165 m ² / g)
* 5: Three types of zinc oxide manufactured by Shodo Chemical Industry Co., Ltd. * 6: Bead stearic acid manufactured by NOF Corporation * 7: Bis- [3- (triethoxysilyl) -propyl] manufactured by Shin-Etsu Chemical Co., Ltd. Tetrasulfide (KBE-846)
* 8: Fine powder sulfur with Jinhua seal oil manufactured by Tsurumi Chemical Industry Co., Ltd. * 9: N-cyclohexyl-2-benzothiazylsulfenamide (Noxeller CZ-G) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

  According to the present invention, by adding silicone-modified lignocellulose to a rubber composition containing silica, it is possible to improve modulus, reduce rolling resistance, improve vulcanization speed, and reduce weight, and for pneumatic tires. In particular, it is useful as a rubber composition for the tread.

Claims (4)

Including 100 parts by mass of diene rubber, 10 to 100 parts by mass of silica , and 1 to 30 parts by mass of silicone-modified lignocellulose in which silane or silicone compound is chemically adsorbed after low-temperature plasma treatment at 20 to 300 ° C. A rubber composition for tires, characterized in that The tire rubber composition according to claim 1, wherein the silane or the silicone compound is Si-H group-containing compound. 3. The tire use according to claim 1, wherein the silicone-modified lignocellulose is obtained by performing chemical adsorption treatment with a silane coupling agent containing a sulfur atom after chemically adsorbing silane or a silicone compound. Rubber composition. The tire rubber composition according to any one of claims 1 to 3 , wherein the low-temperature plasma is water vapor, oxygen, or ammonia plasma.