JPH1046047A - Production of surface treated carbon black and rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain surface treated carbon black capable of improving physical properties such as reduction in tan δ of a vulcanized rubber composition and improvement in wear resistance by sticking a silica in specific thickness and width to the surface of carbon black. SOLUTION: This method for producing surface treated carbon black comprises bringing a silane and/or a polysiloxane in which the whole organic groups are bonded through oxygen to silicon into contact with carbon black at <=200 deg.C to stick the silica in a size of 0.1-20nm thickness and 1-40nm width to the surface of carbon black.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing carbon black in which silanol groups are present on the surface by adhering silica to the surface, and a rubber composition containing the carbon black. The rubber composition obtained is: It is suitably used for manufacturing tire treads and belts.

[0002]

2. Description of the Related Art Tan index is an index of heat generation when a vulcanized rubber composition containing reinforcing particles is repeatedly deformed.
For example, it is known that tan δ at 50 to 70 ° C. should be reduced to reduce the rolling resistance of the tire tread and reduce fuel consumption. On the other hand, the braking characteristics on wet road surfaces are 0
The larger the tan δ around ℃, the better. This tan
As a method of improving the temperature dependence of δ, that is, reducing tan δ at 50 to 70 ° C. and increasing tan δ near 0 ° C., attempts have been made to blend silica as a filler. For example, JP-A-3-252433 describes that silica and a silane coupling agent are blended in a solution polymerization method SBR. Japanese Patent Application Laid-Open No. 7-165991 describes that a silane coupling agent which is particularly bifunctional which can react with silica and rubber is excellent.

This is because particles having silanol groups on the surface, for example, silica particles, are kneaded into a diene rubber together with a silane coupling agent such as bis (3-triethoxysilylpropyl) -tetrasulfane and vulcanized. To
It is known that particles and rubber are chemically bonded via a coupling agent, whereby tan δ around 60 ° C. of the particle-containing vulcanized rubber composition is reduced, and abrasion resistance is improved. It is considered that the improvement of physical properties is seen.

[0004]

However, when silica is blended as a filler, the temperature dependency of tan δ can be improved, but the silica filler has a strong self-cohesive force and is hardly dispersed in rubber. There is a problem that workability is poor. Further, since it is necessary to add an expensive silane coupling agent to silica in an amount of usually 5 to 15%, there is a problem that the compound cost is increased.

[0005] When a silane coupling agent having a sulfur atom as described above is blended without blending a silica filler with carbon black, the particle-containing rubber composition 6
There is a case where tan δ around 0 ° C. is considerably reduced.
However, at low temperature (−10 to 0 ° C.), under low strain (0.1 to 1)
Braking characteristic for complex elastic modulus (E ^*) and dynamic elastic modulus (E ') is high in%) there is a drawback to decrease.

On the other hand, it has been proposed that carbon black to be blended in a rubber composition is surface-treated with silica or silane. For example, JP-A-53-100190 and JP-A-61-291659 describe a method in which an organic compound or organometallic compound of silicon dissolved in a solvent or water is mixed with carbon black and dried. Typically, dimethylpolysiloxane or silicone oil is used as the silicon compound. JP-A-56-38357 proposes a surface-hydrophobized carbon black having a surface treated with a cyclic alkylpolysiloxane or a silicon compound. JP-A-58-125249 describes a carbon black whose surface is coated with a silane coupling agent dissolved in a solvent. JP-A-63-63755 proposes a method of dispersing carbon black in water and neutralizing sodium silicate with sulfuric acid to deposit amorphous silica on the carbon black surface. However, it is hard to say that any of these methods is suitable for industrialization in terms of process and economy such as removal and recovery of a solvent or neutralization operation. Also, Japanese Patent Application Laid-Open No. Hei 4-233976 proposes chemically modifying carbon black with a specific organic silicon compound (specifically, a sulfur-containing silane coupling agent having a specific structure). However, this method also has process and economic problems such as an extraction operation and a post-treatment for denaturation. Moreover, these carbon blacks are silica,
In the method of treating with a surface treating agent such as silane, it is also expected that the surface treating agent does not adhere sufficiently uniformly to all carbon black surfaces.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, the present inventors have determined that carbon black has viscoelastic properties (temperature dependence of tan δ) comparable to that of silica, and that silica has a low dispersibility and a low processability. In order to provide a similarly improved reinforcing particle and a rubber composition containing the same, a method for attaching silica to the surface of carbon black has been studied.

As a result, the surface treatment of the carbon black by the specific method using the specific silicon-containing compound allows the silanol groups to be efficiently and effectively present on the carbon black surface. The rubber composition containing the surface-treated carbon black was found to exhibit excellent properties, and the present invention was completed.

That is, the present invention provides a surface-treated carbon black characterized in that a silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen at 200 ° C. or lower is brought into contact with the surface of the carbon black. And a rubber composition containing the surface-treated carbon black. According to the present invention, since a silanol group can be introduced into the surface of carbon black, a reduction in tan δ of the vulcanized rubber composition at around 60 ° C., which has been attempted by blending particles having a silanol group such as silica particles, has been attempted. Improvements in physical properties such as abrasion can be achieved without blending particles such as silica.

In addition, a low temperature range (-10 to 0) such as when a silane coupling agent having a sulfur atom is blended.
° C), complex elastic modulus (E ^* ) under low strain (0.1-1%)
It is also possible to eliminate the drawback that the braking characteristics are reduced due to high dynamic elastic modulus (E '). Moreover, according to the surface-treated carbon black obtained in the present invention, it is possible to improve the difficulty of dispersibility and the difficulty of processing, which are disadvantages of silica, to the same level as carbon black. Thus, according to the present invention,
A reinforcing particle having both advantages of silica and carbon black, that is, a reinforcing particle having viscoelastic properties (temperature dependence of tan δ) comparable to silica, and having hardly dispersible and difficult to process silica as improved as carbon black. , It is possible to provide a rubber composition comprising the same.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, carbon black as a raw material to be subjected to a surface treatment in the present invention is not particularly limited, but when blended with rubber, various types known as usable in the rubber industry, for example, furnace black (A
Classification according to STM D 1765), channel black, thermal black, acetylene black and the like are preferred. In order to produce such a raw material carbon black, for example, in the case of furnace black, a highly aromatic heavy oil is introduced into a high-temperature gas stream, and the heavy oil can be obtained by incomplete combustion or thermal decomposition.

In the present invention, carbon black is brought into contact with a specific silicon compound. That is, all organic groups come into contact with silane and / or polysiloxane which are bonded to silicon via oxygen. Here, the silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen means that hydrogen, an alkyl group,
A silane to which a vinyl group, a phenyl group or another functional group is bonded, and / or (Si—O) n as a main chain (the main chain may be branched or form a ring);
Refers to a polysiloxane in which hydrogen, an alkyl group, a vinyl group, a phenyl group, or another functional group is bonded via O.

Preferably, a tetraalkoxysilane and / or a polyalkoxypolysiloxane in which a C1-4 alkoxy group is bonded to Si is used. The latter can be easily obtained as the former low condensate. Examples of the latter include those represented by the following general formula (A).

[0014]

Embedded image (RO) ₃ —Si—O— [Si (OR) _n —O _(3-n) ] _m R

Here, n = 1 or 2, m is an integer of 0 or more;
R is a C1-4 alkyl group which may be different from each other. The alkyl group may be replaced by hydrogen. Especially R
= CH _3- , there is an oligomer which is a low condensate of tetramethoxysilane, and "MK" manufactured by Mitsubishi Chemical Corporation.
C-silicate MS51 "is preferable because the content of the monomer (that is, tetramethoxysilane) is as small as 1% by weight or less, and therefore, the quality is excellent, the toxicity due to the monomer is small, and the use is safe. In the present invention, silanes and / or polysiloxanes in which all of these organic groups are bonded to silicon via oxygen can be used as they are, but water and a hydrolysis catalyst are added thereto to carry out hydrolysis. Alternatively, a hydrolyzed condensate obtained by further condensing a hydrolyzed product may be used.

Examples of the hydrolytic condensate include “MKC silicate MS51SG1” (manufactured by Mitsubishi Chemical Corporation) obtained by hydrolyzing and condensing the above oligomer of tetramethoxysilane in alcohol. This is preferably used since a large number of silanol groups are generated by hydrolysis. Since these tetraalkoxysilanes and / or polyalkoxypolysiloxanes have a large number of alkoxy groups, they are extremely excellent in adhering to carbon black and generating silanol groups, and the resulting surface-treated carbon black and a rubber composition containing the same are compounded. It is conceivable that the properties of the product are greatly improved.

The alkoxy group of the tetraalkoxysilane and / or polyalkoxypolysiloxane can be appropriately modified with another organic group by transesterification or other means. Specifically, a desired organic group may be introduced with various active hydrogen-containing compounds, for example, by reacting with an alcohol having a longer-chain organic group to introduce a longer-chain organic group.

Alternatively, a mixture of silane and / or polysiloxane in which all of these organic groups are bonded to silicon via oxygen and other organic components such as a silane coupling agent is brought into contact with carbon black. I do not care. In this case, the other organic components are silanes and / or polysiloxanes 10 in which all organic groups are bonded to silicon via oxygen.
The amount is preferably 50 parts by weight or less, more preferably 20 parts by weight or less based on 0 parts by weight. Examples of the organic component include various resin components and the like in addition to various silane coupling agents, and may be appropriately selected as needed, and may be blended with the silane and / or polysiloxane.

Surface treatment of carbon black with silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen is performed by contacting these compounds with carbon black at 200 ° C. or lower. . 2
When the temperature exceeds 00 ° C., evaporation (gasification) of silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen is promoted, and problems such as a decrease in the adhesion yield during spraying are caused. Occurs.

The amount of the silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen is not particularly limited, but usually 0.1 to 50 parts by weight per 100 parts by weight of carbon black. Can be More preferably, it is 0.2 to 30 parts by weight. If the amount is too small, the effect of improving the temperature dependency of tan δ is small, while if it is too large, the dispersibility during kneading deteriorates and the cost increases.

The contact between the silane and / or polysiloxane in which all of the organic groups are bonded to silicon via oxygen and carbon black can be carried out at 200 ° C. or lower as described above. There is no particular limitation, and the contact can be easily made by adding one to the other. In particular, it is preferable that they are brought into contact in the step of granulating carbon black. That is, by adding or adding silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen to ungranulated carbon black, granulation is performed uniformly and simply. Can be attached to the carbon black surface. The granulation step is preferably wet granulation. From the viewpoint of the process, a method of adding silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen in the same amount of granulated water as ungranulated carbon black is preferable. More preferably, a method is used in which silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen are emulsified and dispersed in granulated water with a nonionic surfactant or the like, and then added. By performing the contact in the "in the presence of water" in this manner, in the subsequent drying step, hydrolysis of the organic group bonded to silicon via oxygen is promoted, and a large number of silanol groups are generated.

After the granulation, a drying step is performed, and the residual moisture in the drying step is preferably adjusted to 5% by weight or less. The drying step can be performed using a device such as a dryer in the presence of moisture. At this time, it is considered that a part of the organic group bonded to silicon via oxygen is hydrolyzed to generate a silanol group.

The surface-treated carbon black obtained by the method of the present invention is not particularly limited, but has a nitrogen specific surface area of 2
0-300m ² / g, DBP 50-250cc / 10
It is preferably 0 g. According to the production method of the present invention,
Carbon black to which silica is attached can be easily produced without requiring complicated operations such as treatment with water glass. Further, as described below, according to the production method of the present invention, substantially the entire amount of the silica component can be uniformly present as a fine region on the surface of the carbon black, so that a large amount of a large effect can be obtained. A silica-attached carbon black exhibiting the effect can be obtained. Also, quality control is easy. Further, according to the present invention, almost all of the charged amount of the silica component,
That is, 80% by weight or more and 90% by weight can be attached to carbon black, and the yield is very good.

The carbon black of the present invention can be obtained by the production method of the present invention described above. That is, the carbon black having silica adhered to the surface, and 80% by weight or more of the adhered silica has a thickness of 0.1 to 2%.
The carbon black has a size of 0 nm and a width of 1 to 40 nm. The attached silica has a thickness of 0.
1 to 15 nm, width 1 to 30 nm, and further width 1 to 20 nm
It can also be. Further, 90% by weight or more of the attached silica can be set in the above range. That is,
The carbon black of the present invention can adhere the silica component in a fine and uniform state, and can exhibit high characteristics. Here, the thickness of the silica refers to a direction perpendicular to the surface of the carbon black, and the width refers to a direction perpendicular to the thickness direction. The size of the silica component can be confirmed by a transmission electron micrograph. Specifically, for a portion confirmed to be a silica component by means such as EDX, the shape is confirmed by a transmission electron microscope photograph,
The thickness and width can be measured by image processing as needed.

Further, almost all of the silica component can be present on the surface of the carbon black. The carbon black of the present invention is treated with a specific silicon compound. That is, it is a silane and / or siloxane in which all organic groups are bonded to silicon via oxygen. Since the surface treatment is performed using such a compound, a large amount of OH groups are easily formed on the surface of the surface-treated carbon black. Can also be excellent in familiarity.

The amount of the rubber is usually 10 to 200 parts by weight, preferably 20 to 1 part by weight, per 100 parts by weight of the rubber component.
50 parts by weight. The rubber component used in the rubber composition of the present invention is not particularly limited, but is preferably a crosslinkable rubber. More preferred is a sulfur-vulcanizable diene rubber. The rubbers may be used alone or in combination of two or more.

In the rubber composition of the present invention, in addition to the surface-treated carbon black obtained by the production method of the present invention, ordinary carbon black or silica may be used in combination. However, it is desirable that the compounding amount does not exceed 5 times the above-mentioned surface-treated carbon black. The rubber composition of the present invention preferably contains a silane coupling agent. As the silane coupling agent, a conventionally used one can be arbitrarily compounded, and particularly, a silane coupling agent having at least bifunctionality capable of reacting with a silanol group and a rubber-based polymer is preferable. Specific examples include bis (3-triethoxysilylpropyl) -tetrasulfide and mercaptopropyltriethoxysilane. This is because the silanol groups on the surface of the carbon black produced according to the present invention react and bond with the alkoxy part of the silane coupling agent during kneading, and the sulfide part reacts with the rubber polymer in the vulcanization reaction. In this case, by using the surface-treated carbon black obtained according to the present invention,
The compounding amount of the silane coupling agent can be smaller than the usual compounding of silica. That is, the usual silica compounding, an expensive silane coupling agent, usually 100 parts by weight of silica,
However, according to the present invention, the compounding amount of the silane coupling agent is determined by adding silica to the surface-treated carbon black obtained by the present invention. Although depending on the amount, 1 to 10 parts by weight is sufficient. This is due to the fact that the total amount of silanol groups present on the carbon black surface is smaller than the silanol groups on the normal silica particle surface, meaning that a sufficient amount of silane coupling agent to react is sufficient. I have. Therefore, according to the present invention, there is also an advantage that the compound cost is lower than that of the silica-based compound.

The rubber composition containing the surface-treated carbon black obtained in the present invention is suitably provided for use in tires such as tire treads, undertreads, side treads, and general rubber members such as vibration-proof rubbers and belts. Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. [Examples 1 to 7] Preparation of surface-treated carbon black "N220"("DIABLACK-
I ": 1000 g of ungranulated product of Mitsubishi Chemical Corporation) is placed in a laboratory granulator. As a silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen,
Oligomers that are low condensates of tetramethoxysilane (trade name: "MKC silicate MS51" Mitsubishi Chemical Corporation)
Is emulsified with a nonionic surfactant (trade name: "Emulgen 920", Kao Corporation) and added to the carbon black together with water. Close the lid of the lab granulator and stir at 60 ° C. for 1 minute. The granules thus obtained were dried with a dryer to obtain surface-treated carbon blacks of Examples 1 to 6.

Next, as silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen,
"MKC silicate MS51" in ethanol, MS
A hydrolyzed condensate obtained by adding 0.57 mole times the amount of water to the alkoxy group of No. 51 and hydrolyzing (trade name: “MKC
The same operation as above was performed using "silicate MS51SG1" (Mitsubishi Chemical Corporation) to obtain a surface-treated carbon black of Example 7.

[Comparative Examples 1 to 3] On the other hand, the same operation as in the Example was performed except that no silane and / or polysiloxane in which all organic groups were bonded to silicon via oxygen and a nonionic surfactant were added. Was performed to obtain a normal carbon black to which silica was not attached in Comparative Example 1. Comparative Example 2 is a simple mixture of silica (trade name: "Nipsil AQ" Nippon Silica Industry Co., Ltd.), and Comparative Example 3 is a mechanical mixture (blend) of carbon black and silica (Nipsil AQ).

Silica content of surface-treated carbon black
Measurement of Amount and Colloidal Characteristics The surface-treated carbon black was ashed at 750 ° C. in accordance with the ash measurement method of JIS K6221, and the ash content was determined. The amount obtained by subtracting the carbon black ash content of Comparative Example 8 to which silica was not attached from this ash content was regarded as the silica content. Table 1 shows the results together with other colloidal characteristic values.
It was shown to. The method for measuring the colloidal characteristic value is as follows.

Nitrogen specific surface area: ASTM D3037 CTAB specific surface area: ASTM D3765 Iodine adsorption amount: JIS K6221 "Testing method for carbon black for rubber" DBP oil absorption: JIS K6221 "Testing method for carbon black for rubber"

Surface treated carbon black-containing rubber composition
Preparation and Measurement of Rubber Physical Properties Each component shown in Table 2 was mixed and kneaded with a Banbury mixer and an open roll mixer according to a conventional method to prepare a rubber composition. (In Table 2, "SBR1502" is styrene butadiene rubber "1502" manufactured by Nippon Synthetic Rubber Co., Ltd.)
(23.5% by weight of styrene). ) These rubber compositions were press-vulcanized at 160 ° C to prepare vulcanized rubber test pieces. Various tests were performed by the following test methods, and the physical properties were measured.

(1) E ^* , tan δ: E ^* and tan δ, which are dynamic viscoelastic properties, were measured under the following conditions using “DVE Rheospectral” manufactured by Rheology Co., Ltd. E ^* : Static strain 10%, dynamic strain (amplitude) 0.3%, frequency 20 Hz, measurement temperature −10 ° C. tan δ: static strain 10%, dynamic strain (amplitude) 4%, frequency 20 Hz, measurement temperature (2) Abrasion resistance: Measured using a Lambourn abrasion tester under the following conditions. Test piece: thickness 10mm, outer diameter 44mm, test load 4k
g, 45% slip ratio between grindstone and test piece, measurement temperature 25 ° C

(3) Degree of dispersion of reinforcing particles in rubber (D
%): Carbon black dispersion degree measurement method ASTM D2
663-B method (aggregate count method). That is,
Vulcanized rubber is sledge type microtome (Leitz)
Slice into a thin film with a light microscope, measure the total cross-sectional area occupied by agglomerates of reinforcing particles (carbon black or silica) of 5 μm or more in the composition with an optical microscope, and calculate the total cross-sectional area of the reinforcing particles added to the composition (calculated value ), The percentage of the reinforcing particles dispersed within 5 μm or less was determined and defined as the degree of dispersion (D%). Table 3 shows the obtained results of (1) to (3).

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

It can be seen from Table 1 that, according to the present invention, the surface treatment of carbon black with silane and / or polysiloxane in which all the organic groups are bonded to silicon via oxygen allows almost theoretical amount of SiO _{2 to} be obtained. It turns out that it is attached to carbon black. In other words, "MKC silicate MS
51 "or" a SiO ₂ minutes theoretical value resulting from MKC Silicate MS51SG1 ", by subtracting the ash content of the carbon black which is not surface-treated from the ash content of the surface-treated carbon black (Comparative Example 1)" deemed SiO ₂ amount " Are almost the same, indicating that the particles are attached in good yield.

As is clear from Tables 2 and 3, carbon black subjected to the surface treatment according to the present invention (Examples 1 to 3)
The rubber composition blended with 7) is a rubber composition blended with ordinary carbon black without surface treatment (Comparative Example 1-
Compared with 1), only tan δ in the high temperature range (60 ° C.) is reduced while tan δ in the low temperature range (0 ° C.) is kept high. That is, when this rubber composition is used for a tire tread or the like, a tire having reduced rolling resistance without sacrificing braking performance on a wet road surface is obtained. Also, the abrasion resistance has not deteriorated.

Further, normally, no silane coupling is added to the carbon black type, but in Comparative Example 1-2 in which 5 parts by weight of Si69 is added, the tan δ balance between the low temperature range and the high temperature range is quite close to that of the silica type, and is improved. I have. However, since the complex elastic modulus E * at low temperature and under low strain is high, the braking characteristics particularly on a road surface with a low friction coefficient are inferior. On the other hand, in the example, the E * is low, and it can be seen that it is improved.

Next, when compared with Comparative Example 2 in which ordinary silica was blended, the tan δ balance in the low temperature region and the high temperature region was the same (as silica), and the abrasion resistance and the dispersibility of the reinforcing particles were low. Excellent (normal carbon black). That is, the examples have viscoelastic properties comparable to silica (tan δ balance between low and high temperatures and E ^* properties under low temperature and low strain), and abrasion resistance and particle dispersibility comparable to carbon black. I understand.

Comparative Example 3 is a blend of ordinary carbon black and silica. As is clear from comparison with Example 5 in which the total silica content in the particles is almost the same, the effect of the present invention was not obtained by a simple blend of carbon black and silica, and the surface was treated by the method of the present invention. It can be seen that it is expressed only using carbon black.

Examples 8 and 9 "N339" manufactured by Mitsubishi Chemical Corporation as carbon black
(Iodine adsorption amount 92 m ² / g, nitrogen adsorption specific surface area 105
m ² / g), and using the same method as in Example 1 except that “MS-51” was used so that the amount of silica was 1% by weight and 5% by weight (in terms of the charged amount), respectively. The attached carbon black was obtained. Table 4 shows the conductivity (volume resistivity) of the obtained carbon black. Furthermore,
By using these silica-attached carbon blacks,
Each component shown in Table 5 was mixed and kneaded with a Banbury mixer and an open roll mixer to prepare a rubber composition.
Table 4 shows the physical properties (tan δ) of the obtained rubber composition.

A transmission electron micrograph (2,000,000) of the carbon black to which the silica obtained in Example 8 was adhered.
1 is shown in FIG. 1, and the EDX spectra of the A part and the B part in FIG. 1 are shown in FIGS. 2 and 3, respectively. Thereby, the part A is a silica component, and the thickness of the silica component is about 10 n.
It can be seen that m and the width are about 20 nm. The same applies to other parts of the carbon black.

Comparative Examples 4 and 5 Carbon black was charged into the apparatus used in Example 1 and sodium silicate (reagent grade) diluted with water so as to have a concentration of 1% by weight was used. %. Further, 5% sulfuric acid was added to adjust the pH to 9, and the lid of the laboratory granulator was closed.
Stir at 0 ° C. for 1 minute at high speed. The granules thus obtained were dried with a dryer to obtain carbon black to which silica had adhered. Conductivity (volume resistivity) as in Example 8
Is shown in Table 4. A rubber composition was prepared in the same manner as in Example 8, and the physical properties (tan δ) of the obtained rubber composition are shown in Table 4.

[0047]

[Table 4] (The conductivity (Ω · cm) of “N339” is 8.76.
E + 03, conductivity (Ω · cm) of silica is 5.75E
+13. )

[0048]

[Table 5] In Table 5, * 3), * 4), * 5) and * 6) are as shown in Table 2.
Same as inside. Aroma oil is available from Fujikosan Co., Ltd.
Was used.

As is clear from Table 4, Examples 8 and 9 treated with a siloxane compound are superior in both rubber physical properties and conductivity as compared with Comparative Examples 4 and 5 treated with water glass (sodium silicate). You can see that.

[0050]

As described above, according to the present invention, since a silanol group can be introduced into the surface of carbon black, the vulcanized rubber composition, which has been tried by blending particles having a silanol group such as silica particles, has been tried. Improvement of physical properties such as reduction of tan δ around 60 ° C and improvement of wear resistance,
This can be achieved without blending particles such as silica. In addition, the complex elastic modulus (E ^* ) and the dynamic modulus in a low temperature range (−10 to 0 ° C.) and a low strain (0.1 to 1%), such as when a silane coupling agent having a sulfur atom is blended, It is also possible to eliminate the drawback that the braking characteristics are reduced due to the high elastic modulus (E '). Furthermore, according to the surface-treated carbon black of the present invention, the dispersibility, which is a disadvantage of silica,
Difficult-to-workability can be improved to the same level as carbon black. Therefore, according to the present invention, reinforcing particles having both advantages of silica and carbon black, that is, having viscoelastic properties (temperature dependence of tan δ) comparable to silica, and having low dispersibility and difficult processing properties of silica as compared with carbon black. And a rubber composition obtained by blending the reinforcing particles.

[Brief description of the drawings]

FIG. 1 is a transmission electron micrograph showing a particle structure of carbon black to which silica obtained in Example 8 is adhered.

FIG. 2 is a view showing an EDX spectrum of a part A in FIG.

FIG. 3 is a view showing an EDX spectrum of a portion B in FIG. 1;

Claims (11)

[Claims] 1. A carbon black having silica attached to its surface, wherein the attached silica has a thickness of 0.1 to 20 nm and a width of 1 to 40 nm. 2. A method for producing a surface-treated carbon black, comprising contacting silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen at 200 ° C. or lower with carbon black. 3. Granulation while adding silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen to ungranulated carbon black, or carbon black after adding this. The surface-treated carbon according to claim 2, wherein the silane and / or polysiloxane in which all the organic groups are bonded to silicon via oxygen are brought into contact with the carbon black by granulation in the carbon black granulation step. Black manufacturing method. 4. The method for producing a surface-treated carbon black according to claim 3, wherein the step of granulating the carbon black is a wet granulation, and after the granulation, a step of drying with a dryer until the water content becomes 5% by weight or less. . 5. The silane according to claim 2, wherein all the organic groups are bonded to silicon via oxygen and / or the groups bonded to silicon in the polysiloxane are alkoxy groups. A method for producing surface-treated carbon black. 6. The method according to claim 5, wherein the alkoxy group is a methoxy group.
The method for producing the surface-treated carbon black according to the above. 7. The carbon black according to claim 2, wherein the silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen are condensates of tetraalkoxysilane. Production method. 8. The method for producing a surface-treated carbon black according to claim 7, wherein the tetraalkoxysilane is tetramethoxysilane. 9. The use amount of silane and / or polysiloxane in which all organic groups are bonded to silicon via oxygen is 0.1 to 50 parts by weight based on 100 parts by weight of carbon black. The method for producing a surface-treated carbon black according to any one of the above. 10. A rubber composition obtained by blending carbon black obtained by the method according to claim 2 with a rubber component. 11. A rubber composition comprising the carbon black according to claim 1 and a rubber component.