JP2002338846A - Black composite filling material and tread rubber composition using black composite filling material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a black composite filling material which has high black chromaticity, is suppressed from discoloring by light, and has low intrinsic volume resistance and excellent dispersibility for producing a tread rubber composition that is suppressed from discoloring by light, has a low electric resistance, and is excellent in abrasion resistance and tensile strength. SOLUTION: The black composite filling material is a powder of a composite silica particle which comprises a powder of a silica particle and has an average particle size of 0.001-0.5 μm, wherein the silica particle is coated with an organosilane compound produced from an alkoxysilane or a polysiloxane on the particle surface and is adhered by a carbon black on at least one part of the coated surface; and the carbon black adheres in an amount of 1-1,000 parts by weight relative to 100 parts by weight of the powder of the silica particle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention provides a black composite filler material having a high blackness, suppressing fading due to light, and having a low volume resistivity and excellent dispersibility. When a black composite filler is blended with rubber, the purpose of the present invention is to provide a tread rubber composition in which fading due to light is suppressed, and which has a low electric resistance value and excellent abrasion resistance and tensile strength. I do.

[0002]

[Prior art]

[0003] From the viewpoint of running safety, automobile tires are required to have high grip, abrasion resistance and breaking strength on wet road surfaces. In recent years,
From the viewpoint of energy saving and resource saving, development of so-called fuel-efficient tires that reduce the rolling resistance of automobile tires and reduce fuel consumption has been actively conducted.

[0004] In addition, when the electric resistance value of an automobile tire is high, a discharge due to electrostatic breakdown causes noise to an electronic device such as a radio, or static electricity generated in the automobile is charged and sparks during refueling or the like. Therefore, it is strongly required that the electric resistance value be low because of the danger of ignition.

Conventionally, rubber compositions such as tires have been reinforced,
Carbon black is blended for the purpose of improving wear resistance and reducing electric resistance. However, it is known that tires containing carbon black have high rolling resistance, and therefore increase the fuel consumption of automobiles.

Therefore, it has been proposed to mix silica particle powder capable of reducing the rolling resistance of a tire as compared with carbon black as a filler for reinforcing rubber for tires and the like, and it has already been put to practical use (see, Kaihei 3-239
737).

However, the silica particle powder has a silanol group as a functional group on the particle surface, and the particles tend to agglomerate due to the hydrogen bond of the silanol group. Dispersion was difficult. In addition, the silica particle powder has a low compatibility with rubber generally used for tires because the silanol groups on the particle surface show hydrophilicity, and has a lower reinforcing effect than when carbon black is blended. It is known.

Therefore, it has been proposed to improve the dispersibility in rubber by treating the surface of silica particle powder with an organosilicon compound (JP-A-8-245838).

When silica particle powder is used as the filler, the electrical resistance of the tire increases due to the non-conductivity of the silica particle powder. Has also been used in combination, and has already been put to practical use. (JP-A-52-93452, JP-A-3-93452)
239737, JP-A-8-245838,
Japanese Patent No. 2722077, Japanese Patent No. 2788212, Japanese Patent No. 3160552, etc.)

[0010] Furthermore, tires of automobiles are generally black, and it is strongly required that the degree of blackness be high from the viewpoint of visibility and that fading due to light be suppressed.

[0011]

A tread rubber composition which suppresses fading due to light, and has a low electric resistance value and excellent abrasion resistance and tensile strength, is currently the most demanded. However, a tread rubber composition having such properties has not yet been obtained.

The tread tire composition described in the above-mentioned Japanese Patent Application Laid-Open No. 3-239737 discloses a styrene-based composition obtained by copolymerizing styrene and butadiene with an organolithium compound.
Silica particle powder 10 to 15 parts per 100 parts by weight of blend rubber containing 30 parts by weight or more of butadiene copolymer
The present invention relates to a rubber composition comprising 0 parts by weight and 0 to 100 parts by weight of carbon black. However, since the dispersion of the silica particle powder in the rubber composition is not uniform, excellent wear resistance and tensile strength are obtained. Is difficult to obtain,
Since dispersion of carbon black is also hindered by the silica particle powder, it has been difficult to reduce the electric resistance value.

The tires described in JP-A-52-93452, Japanese Patent No. 2722077 and Japanese Patent No. 3160552 each include silica particles having a surface coated with carbon, or a filler containing the silica particles powder. As for the rubber composition containing as, as all, since the carbon black layer is formed on the silica surface by thermally decomposing the organic matter, as shown in the Comparative Examples below, the carbon black on the silica particle surface Adhesive strength is weak, and when kneaded into the rubber composition, carbon black is desorbed and the silica particle surface is exposed, so that dispersion in the rubber composition becomes uneven, abrasion resistance and tensile strength Decrease.

The rubber composition described in the aforementioned Japanese Patent No. 2788212 relates to a rubber composition for a tire tread containing carbon black surface-treated with silica having a silica amount of 0.1 to 50% by weight. Since the adhesion strength of silica to the surface of carbon black is weak, when kneaded into the rubber composition, the silica is detached from the surface of carbon black, preventing uniform dispersion.

Accordingly, an object of the present invention is to provide a tread rubber composition which is resistant to fading due to light and has a low electric resistance value and excellent abrasion resistance and tensile strength. It is a technical object of the present invention to obtain a filling reinforcing material which has a high dispersibility, suppresses fading due to light, and has a low volume resistivity and excellent dispersibility.

[Means for Solving the Problems]

The above technical object can be achieved by the present invention as described below.

That is, according to the present invention, the average particle diameter of the silica particle powder in which the particle surface is coated with an organosilane compound or polysiloxane formed from alkoxysilane, and at least a part of the coating is coated with carbon black. A composite silica particle powder of 0.001 to 0.5 μm, wherein the amount of the carbon black attached is 1 to 1000 parts by weight based on 100 parts by weight of the silica particle powder. (Invention 1).

Further, the present invention is a black composite filling material characterized in that the particle surface of the composite silica particle powder according to the present invention 1 is coated with a fatty acid, a fatty acid metal salt or a coupling agent. Invention 2).

In the present invention, the particle surface of the silica particle powder according to the present invention 1 or 2 is selected from aluminum hydroxide, aluminum oxide, silicon hydroxide and silicon oxide in advance. A black composite filler material characterized by being coated with at least one kind of intermediate coating. (Invention 3)

Further, the present invention is a tread rubber composition using the black composite filler material according to any one of the present inventions 1 to 3. (Invention 4)

The structure of the present invention will be described in detail as follows.

First, the black composite filling material according to the present invention comprises:
It is composed of silica particle powder in which an organosilane compound or polysiloxane formed from alkoxysilane is coated on the particle surface, and carbon black is adhered to at least a part of the coating.

The silica particles in the present invention include:
Any substance can be used as long as it is a substance containing silica as a main component, such as white carbon such as silicic anhydride, hydrous silicic acid, anhydrous silicate and hydrous silicate. Considering the dispersibility of the obtained black composite filler, silicic anhydride and hydrous silicic acid are preferred.

The particle shape of the silica particle powder may be any shape such as a spherical shape, a granular shape, an irregular shape, a needle shape and a plate shape. Considering the dispersibility of the obtained black composite filler in the tread rubber composition, spherical particles or granular particles are preferable.

The silica particle powder has an average particle diameter of 0.001 to 0.50 μm, preferably 0.002 to
０．４0.45 μm, more preferably 0.003 to 0.40
μm.

When the average particle diameter exceeds 0.50 μm, the resulting black composite filler becomes coarse particles, so that the dispersibility in the tread rubber composition decreases, and
When the particle size is less than 1 μm, aggregation tends to occur due to an increase in intermolecular force due to finer particles, so that uniform coating treatment with alkoxysilane or polysiloxane on the particle surface and uniform adhesion treatment with carbon black are difficult. Become.

The BET specific surface area of the silica particles is 20
m ² / g or more is preferable. BET specific surface area value of 20 m ² /
If less than g, the silica particles are coarse or particles that have been sintered between the particles and between the particles, and the resulting black composite filler becomes coarse particles, so the tread rubber composition contains Dispersibility decreases. Considering the dispersibility in the tread rubber composition, the BET specific surface area value is more preferably at least 25 m ² / g, most preferably 3 m ² / g.
0 m ² / g or more. Considering the uniform coating treatment with the alkoxysilane or polysiloxane and the uniform adhesion treatment with the carbon black on the particle surface of the silica particle powder, the upper limit is preferably 500 m ² / g, more preferably 400 m ² / g, and most preferably 400 m ² / g. Preferably 300 m ² /
g.

The volume resistivity value of the silica particle powder is usually 1.0 × 10 ⁵ Ω · cm or more.

The organosilane compound produced from alkoxysilane in the present invention (hereinafter referred to as "organosilane compound") is an organosilane compound produced from alkoxysilane represented by the following chemical formula 1.

[0030]

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As the alkoxysilane, specifically,
Methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, etc. Can be

In consideration of the adhesion effect and desorption rate of carbon black, an organosilane compound formed from methyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, isobutyltrimethoxysilane, and phenyltriethoxysilane is preferable. Organosilane compounds formed from ethoxysilane, methyltrimethoxysilane and phenyltriethoxysilane are more preferred.

As the polysiloxane in the present invention, a polysiloxane represented by Chemical formula 2, a modified polysiloxane represented by Chemical formula 3, a terminal modified polysiloxane represented by Chemical formula 4, or a mixture thereof can be used.

[0034]

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[0035]

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[0036]

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In consideration of the adhesion effect and desorption rate of carbon black, polysiloxanes having methyl hydrogen siloxane units, polyether-modified polysiloxanes, and terminal carboxylic acid-modified polysiloxanes whose terminals have been modified with carboxylic acids are preferred.

The coating amount of the organosilane compound or the polysiloxane is preferably 0.02 to 5.0% by weight in terms of Si with respect to the organosilane compound-coated silica particle powder or the polysiloxane-coated silica particle powder. Preferably it is 0.03-4.0% by weight, and even more preferably 0.05-3.0% by weight.

When the amount is less than 0.02% by weight, it is difficult to attach 1% by weight or more of carbon black to 100 parts by weight of the silica particle powder.

In order to adhere a sufficient amount of carbon black to the silica particle powder, the upper limit of the coating amount is sufficient to be 5.0% by weight.

The amount of carbon black attached is 1 to 1000 parts by weight based on 100 parts by weight of the silica particle powder.
Preferably 30 to 750 parts by weight, more preferably 50 to 750 parts by weight.
500 parts by weight.

If the amount is less than 1 part by weight, the adhesion amount of carbon black is insufficient, the volume resistivity cannot be sufficiently reduced, and it is difficult to obtain a black composite filling material having sufficient blackness. is there.

When the amount exceeds 1,000 parts by weight, a black composite filler having a sufficient degree of blackness and a specific volume resistivity can be obtained. However, the carbon black adheres in a large amount, so that carbon black is easily detached. And dispersibility in the tread rubber composition is reduced.

The particle shape and particle size of the black composite filler according to the present invention greatly depend on the particle shape and particle size of the silica particles as core particles, and have a particle morphology similar to the core particles.

The particle size of the black composite filling material according to the present invention is such that the average particle size is 0.001 to 0.50 μm, preferably 0.002 to 0.45 μm, more preferably 0.02 to 0.45 μm.
03 to 0.40 μm.

When the average particle size exceeds 0.50 μm, the particle size is too large, and it is difficult to disperse the particles in the tread rubber composition. When the particle size is less than 0.001 μm, aggregation tends to occur due to an increase in intermolecular force due to finer particles, so that dispersion in the tread rubber composition becomes difficult.

[0047] BET specific surface area value of the black composite filling material according to the present invention is preferably 20 to 500 m ² / g, more preferably 25~400m ² / g, and most preferably 30 to 3
00 m ² / g. When the BET specific surface area value is less than 20 m ² / g, the particles are coarse, or the particles are sintered between the particles, and the dispersibility in the tread rubber composition is reduced. . If the BET specific surface area exceeds 500 m ² / g, aggregation tends to occur due to an increase in intermolecular force due to finer particles, so that dispersibility in the tread rubber composition decreases.

The blackness of the black composite filling material according to the present invention is preferably such that the L ^* value is 22.0 or less, more preferably 21.0 or less, and most preferably 20.0 or less. L
^{* When the} value exceeds 22.0, the lightness increases and it is difficult to say that the blackness is excellent. The lower limit of L ^* value is 1
4.5.

The black composite filler according to the present invention preferably has a volume resistivity of less than 1.0 × 10 ⁵ Ω · cm, more preferably 5.0 × 10 ⁴ Ω · cm or less, most preferably 1 × 10 ⁴ Ω · cm or less. 0.0 × 10 ⁴ Ω · cm or less. When the volume resistivity is 1.0 × 10 ⁵ Ω · cm or more, it is difficult to sufficiently reduce the volume resistivity of the obtained tread rubber composition. The lower limit of the volume resistivity is 1.0 ×
It is 10 Ω · cm.

Light fastness of the black composite filling material according to the present invention
Is ΔE in the evaluation method described later. ^*5.0 or less in value
Is more preferable, and it is more preferably 4.0 or less.

The desorption rate of carbon black in the black composite filling material according to the present invention is preferably 20% or less, more preferably 15% or less. Desorption rate of carbon black is 2
If it exceeds 0%, the dispersed carbon black may hinder uniform dispersion in the tread rubber composition.

The black composite filler according to the present invention may further comprise, if necessary, a particle surface of the black composite filler, further comprising a fatty acid,
It may be coated with a fatty acid metal salt or a silane coupling agent, and the dispersibility in the tread rubber composition is improved as compared with a case where it is not coated with a fatty acid, a fatty acid metal salt or a silane coupling agent.

As the fatty acid in the present invention, a saturated or unsaturated fatty acid can be used.
Are preferred.

As the fatty acid metal salt in the present invention, salts of a saturated or unsaturated fatty acid and a metal can be used, and a fatty acid having 12 to 18 carbon atoms and an alkaline earth metal such as magnesium, calcium, strontium and barium can be used. It is preferable to use salts with alkali metals such as lithium, sodium and potassium, and metals such as zinc, aluminum, copper, iron, lead and tin. Considering the dispersibility in the tread rubber composition, an alkaline earth metal salt of stearic acid or zinc stearate is preferred.

As the silane coupling agent in the present invention, those generally used for compounding rubber can be used. For example, vinyltrichlorosilane,
Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β
-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane,
N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxy Silane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, bis- (3-
(Trimethoxysilyl) propyl) tetrasulfen,
γ-trimethoxysilylpropyldimethylthiocarbamyltetrasulfene and γ-trimethoxysilylpropylbenzothiazyltetrasulfene.

Taking into account the reinforcing effect in the tread rubber composition, those having a functional group such as polysulfide, mercapto group, or epoxy group capable of reacting with a carbon-carbon double bond of rubber are preferred. And polysulfides such as bis- (3- (trimethoxysilyl) propyl) tetrasulfene, γ-trimethoxysilylpropyldimethylthiocarbamyltetrasulfene, γ-trimethoxysilylpropylbenzothiazyltetrasulfene And those having a mercapto group include γ-
There are mercaptopropyltrimethoxysilane and the like, and those having an epoxy group include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane.

The coating amount of the fatty acid, fatty acid metal salt or silane coupling agent is preferably 0.1 to 10.0% by weight in terms of C based on the weight of the black composite filling material coated with fatty acid, fatty acid metal salt or silane coupling agent. , More preferably 0.2 to 7.5% by weight, most preferably 0.3 to 5.0% by weight.
% By weight.

If the amount is less than 0.1% by weight, the effect of improving dispersibility in the tread rubber composition cannot be obtained. 1
If the content exceeds 0.0% by weight, the effect of improving the dispersibility in the tread rubber composition is saturated, so that there is no point in covering more than necessary.

The black composite filler according to the present invention 2 has a particle size, a BET specific surface area, a volume resistivity, a blackness, a light resistance and a carbon black similar to those of the black composite filler according to the present invention 1. Has a desorption rate.

The black composite filling material according to the present invention may have, if necessary, a surface of silica particles in advance of at least one selected from hydroxides of aluminum, oxides of aluminum, hydroxides of silicon and oxides of silicon. It may be coated with one kind of intermediate coating, and the desorption rate of carbon black from the particle surface of the silica particle powder can be further reduced as compared with the case where the coating is not coated with the intermediate coating.

[0061] The coating amount by the intermediate coatings, Al converted the silica particles coated with an intermediate coating, SiO ₂
0.0 as the sum of the conversion or Al conversion and SiO ₂ conversion
1-20% by weight is preferred.

If the amount is less than 0.01% by weight, the effect of reducing the desorption rate of carbon black cannot be obtained. 0.0
With a coating amount of 1 to 20% by weight, the effect of reducing the desorption rate of carbon black can be sufficiently obtained.

The black composite filler according to the third aspect of the present invention has substantially the same particle size, BET specific surface area, volume resistivity, blackness and light resistance as the black composite filler according to the first and second aspects of the present invention. have. Also, the desorption rate of carbon black is improved by coating with an intermediate coating,
The desorption rate is preferably 15% or less, more preferably 10%.
It is as follows.

Next, a tread rubber composition using the black composite filler according to the present invention will be described.

In the tread rubber composition using the black composite filler according to the present invention 1, the dispersion state is preferably 4 or 5,
More preferably 5, the wear resistance is preferably 103 or more in relative value, more preferably 105 or more, and the volume resistivity is preferably 1.0 × 10 ⁵ Ω · cm or less,
More preferably, it is 5.0 × 10 ⁴ Ω · cm or less, the tensile strength is preferably 23.0 MPa or more, more preferably 23.5 MPa or more, and the light resistance is ΔE ^* value of 5.
0 or less, more preferably 4.5 or less,
Most preferably, it is 4.0 or less.

The dispersion state of the tread rubber composition using the black composite filler according to the present invention 2 is preferably 5,
The wear resistance is preferably 105 or more, more preferably 10 or more.
7 or more, and the volume resistivity is 1.0 × 10 ⁵ Ω · c
m or less, more preferably 5.0 × 10 ⁴ Ω ·
cm or less, the tensile strength is preferably 23.5 MPa or more, more preferably 24.0 MPa or more, and the light resistance is preferably ΔE ^* value of 4.5 or less, more preferably 4.0 or less, Most preferably, it is 3.5 or less.

The dispersion state of the tread rubber composition using the black composite filler according to the third aspect of the present invention is preferably 5,
The wear resistance is preferably 105 or more, more preferably 10 or more.
7 or more, and the volume resistivity is 1.0 × 10 ⁵ Ω · c
m or less, more preferably 5.0 × 10 ⁴ Ω ·
cm or less, the tensile strength is preferably 23.5 MPa or more, more preferably 24.0 MPa or more, and the light resistance is preferably ΔE ^* value of 4.5 or less, more preferably 4.0 or less, Most preferably, it is 3.5 or less.

The compounding ratio of the black composite filler in the tread rubber composition according to the present invention can be used in the range of 10 to 200 parts by weight with respect to 100 parts by weight of the rubber component. Considering
Preferably from 15 to 150 parts by weight, more preferably from 20 to
100 parts by weight.

The base material constituting the tread rubber composition according to the present invention includes, as necessary, a vulcanizing agent, a vulcanization accelerator, and a cup which are commonly used in the tread rubber composition, together with a black composite filler and a known rubber. Various additives such as a ring agent, a filler, a plasticizer, and an antioxidant are blended.

As the rubber, natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), butyl rubber (IIR), halogenated butyl rubber (X-II)
R), acrylonitrile butadiene rubber (NBR), chloroprene rubber, ethylene-propylene copolymer rubber,
Ethylene-propylene-diene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, isoprene-butadiene copolymer rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber , Silicone rubber, fluorine rubber, urethane rubber and mixtures thereof can be used. As the main components of the rubber, natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), butyl rubber (IIR), halogenated butyl rubber (X-IIR), It is preferable to include a diene rubber such as acrylonitrile butadiene rubber (NBR).

The tread rubber composition according to the present invention is kneaded together with the rubber and the black composite filler material and, if necessary, various additives by a conventional method using a Banbury mixer, a mixing roll or the like, and then kneaded at 120 to 180. It is obtained by vulcanization at ° C.

Next, a method for producing the black composite filling material according to the present invention will be described.

The black composite filling material according to the present invention is obtained by mixing silica particle powder and alkoxysilane or polysiloxane, coating the particle surface of the silica particle powder with alkoxysilane or polysiloxane, and then coating the mixture with alkoxysilane or polysiloxane. It can be obtained by mixing the coated silica particle powder and carbon black fine particle powder.

For coating the silica particle powder with the alkoxysilane or polysiloxane, the silica particle powder and the alkoxysilane solution or polysiloxane are mechanically mixed and stirred, or the silica particle powder is coated with the alkoxysilane solution or the polysiloxane. What is necessary is just to mix and stir mechanically while spraying. Almost all of the added alkoxysilane or polysiloxane is coated on the particle surface of the silica particle powder.

The coated alkoxysilane may be partially coated as an organosilane compound generated from the alkoxysilane, which is generated through a coating process. Even in this case, it does not affect the subsequent adhesion of carbon black.

In order to uniformly coat the surface of the silica particle powder with the alkoxysilane or polysiloxane, it is preferable to previously disaggregate the silica particle powder using a pulverizer.

Mixing and stirring of the silica particle powder and the alkoxysilane or polysiloxane, and mixing and stirring of the carbon black fine particle powder and the silica particle powder coated with an organosilane compound or polysiloxane formed from alkoxysilane on the particle surface. As a device for performing this, a device capable of applying a shearing force to the powder layer is preferable, and in particular, a device capable of simultaneously performing shearing, spatula and compression, such as a wheel-type kneader, a ball-type kneader, and a blade A mold kneader or a roll kneader can be used. In practicing the present invention, a wheel-type kneader can be used more effectively.

Specific examples of the wheel-type kneader include edge runners (synonyms of “mix miller”, “Simpson mill”, and “sand mill”), multi-mul, stots mill, wet pan mill, conner mill, and ring miller. And the like, preferably an edge runner, a multiple, a Stotts mill, a wet pan mill, and a ring muller, and more preferably an edge runner. Examples of the ball-type kneader include a vibration mill and the like. Specific examples of the blade type kneader include a Henschel mixer, a planetary mixer, and a Nauta mixer. Specific examples of the roll-type kneader include an extruder.

The conditions during mixing and stirring are such that the linear load is 19.6 so that the surface of the silica particles is coated with the alkoxysilane or polysiloxane as uniformly as possible.
１９1960 N / cm (2 to 200 kg / cm), preferably 98 to 1470 N / cm (10 to 150 kg / c)
m), more preferably 147 to 980 N / cm (15 to 980 N / cm).
100 kg / cm), and the processing time may be appropriately adjusted within the range of 5 to 120 minutes, preferably 10 to 90 minutes. The stirring speed is 2 to 2000 rpm, preferably 5 to 1000 rpm, more preferably 10 to 800 rpm.
The processing conditions may be appropriately adjusted within the range of m.

The addition amount of the alkoxysilane or polysiloxane is 0.15 to 100 parts by weight of the silica particle powder.
~ 45 parts by weight are preferred. If the amount is less than 0.15 parts by weight, it is difficult to attach carbon black sufficiently to improve the blackness. By adding 0.15 to 45 parts by weight, carbon black can be sufficiently adhered, so that it is meaningless to add more than necessary.

After coating the surface of the silica particle powder with alkoxysilane or polysiloxane, carbon black fine particle powder is added, and the mixture is stirred to deposit carbon black on the alkoxysilane coating or polysiloxane coating. If necessary, drying or heat treatment may be further performed.

The carbon black fine particles are preferably added little by little over time, especially over about 5 to 60 minutes.

The conditions during mixing and stirring are such that the linear load is 19.6 to 19 so that the carbon black adheres uniformly.
60 N / cm (2-200 kg / cm), preferably 9
8 to 1470 N / cm (10 to 150 Kg / cm), more preferably 147 to 980 N / cm (15 to 100 Kg)
g / cm), and the treatment time is 5 to 300 minutes, preferably 10 minutes.
The processing conditions may be appropriately adjusted within a range of up to 240 minutes. The stirring speed is 2 to 2000 rpm, preferably 5 to 1
The processing conditions may be appropriately adjusted within the range of 000 rpm, more preferably in the range of 10 to 800 rpm.

As the carbon black fine particle powder used in the present invention, commercially available furnace black, channel black and the like can be used.
50, # 3150, # 3250, # 3750, # 395
0, MA100, MA7, # 1000, # 2400B,
# 30, MA77, MA8, # 650, MA11, # 5
0, # 52, # 45, # 2200B, MA600, etc. (trade name: Mitsubishi Chemical Co., Ltd.) Seast 9H, Seast 7H, Seast 6, Seast 3H, Seast 300,
Seast FM etc. (trade name, Tokai Carbon Co., Ltd.), Raven 1250, Raven 860,
Raven 1000, Raven 1190 ULTR
A (trade name: Colombian Chemicals Company (manufactured)), Ketjen Black EC, Ketjen Black EC600JD (trade name: Ketjen Black International K.K.), BLACK PEA
RLS-L, BLACK PEARLS 1000, B
LACK PEARLS 4630, VULCAN X
C72, REGAL 660, REGAL 400 (trade name: Cabot Specialty Chemicals, Inc.) or the like can be used.

The average particle diameter of the carbon black fine particles is preferably about 0.005 to 0.05 μm, more preferably 0.1 to 0.05 μm.
It is about 010 to 0.035 μm.

When the particle size is less than 0.005 μm, the carbon black fine particle powder becomes too fine, so that handling becomes difficult.

If the thickness exceeds 0.05 μm, the particle size of the carbon black fine particles is large, so that a very large mechanical shear force is required to uniformly adhere to the alkoxysilane coating, organosilane compound coating or polysiloxane coating. Is required, which is industrially disadvantageous.

The addition amount of the carbon black fine particles was
It is 1 to 1000 parts by weight based on 100 parts by weight of the silica particle powder. If the amount is less than 1 part by weight, the amount of carbon black attached is insufficient, and sufficient blackness cannot be obtained.
When the amount exceeds 1000 parts by weight, sufficient blackness is obtained, but carbon black adheres to the particle, so that carbon black is easily detached from the particle surface. As a result, dispersibility in the tread rubber composition is improved. Decrease.

The heating temperature in the drying or heating treatment is usually preferably from 40 to 150 ° C., more preferably 6 to 150 ° C.
0 to 120 ° C, and the treatment time is preferably 10 minutes to 12 hours, more preferably 30 minutes to 3 hours.

The alkoxysilane used for coating the obtained black composite filling material is coated with an organosilane compound finally produced from the alkoxysilane through these steps.

The black composite filling material according to the present invention 2 can be obtained by coating the black composite filling material obtained above with a fatty acid, a fatty acid metal salt or a silane coupling agent.

The coating of the black composite filling material with a fatty acid, a fatty acid metal salt or a silane coupling agent may be performed by mechanically mixing and stirring the black composite filling material and a fatty acid, a fatty acid metal salt or a silane coupling agent while heating. .

The amount of the fatty acid, fatty acid metal salt or silane coupling agent is preferably 0.13 to 67 parts by weight based on 100 parts by weight of the black composite filler. 0.13-67
The dispersibility of the black composite filler in the tread rubber composition can be further improved by the addition amount by weight.

The heating temperature is preferably at least 40 ° C., more preferably at least 50 ° C., most preferably at least 60 ° C. The upper limit is determined by the melting point or boiling point of the fatty acid, fatty acid metal salt and coupling agent to be coated. is there.

Before the mixing and stirring with the alkoxysilane or the polysiloxane, if necessary,
It may be previously coated with an intermediate coating of at least one selected from aluminum hydroxide, aluminum oxide, silicon hydroxide and silicon oxide.

The coating with the intermediate coating is carried out by adding an aluminum compound to a water suspension obtained by dispersing silica particle powder.
By adding a silicon compound or both compounds and mixing and stirring, or, if necessary, adjusting the pH value after mixing and stirring, the particle surface of the silica particle powder is used to oxidize aluminum hydroxide and aluminum. object,
It is coated with an intermediate coating consisting of at least one selected from the group consisting of hydroxides of silicon and oxides of silicon, and then filtered, washed with water, dried and pulverized. Degas if necessary.
Consolidation treatment or the like may be performed.

As the aluminum compound, aluminum salts such as aluminum acetate, aluminum sulfate, aluminum chloride and aluminum nitrate, and alkali aluminates such as sodium aluminate can be used.

As the silicon compound, No. 3 water glass, sodium orthosilicate, sodium metasilicate and the like can be used.

[0099]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment of the present invention is as follows.
It is as follows.

The average particle diameter of each of the silica particle powder, the carbon black fine particle powder, and the black composite filler material is obtained by enlarging the electron micrograph (× 50,000) four times in the vertical and horizontal directions, respectively. About 3 particles shown
The particle diameters of 50 particles were measured, and the average value was shown.

The specific surface area was shown by a value measured by the BET method.

The amount of Al present on the surface of the silica particles is:
Using a "fluorescent X-ray analyzer 3063M" (manufactured by Rigaku Denki Kogyo Co., Ltd.), the measurement was carried out according to JIS K0119 "General rules for fluorescent X-ray analysis".

The amount of the organosilane compound or polysiloxane formed from the alkoxysilane coated on the particle surface of the silica particle powder, the amount of carbon black adhering to the black composite filler, and the particles of the black composite filler The amount of the fatty acid, fatty acid metal salt or silane coupling agent coated on the surface can be determined by measuring the carbon amount using "HORIBA Metal Carbon / Sulfur Analyzer EMIA-2200" (manufactured by HORIBA, Ltd.). I asked.

The desorption rate (%) of carbon black adhering to the black composite filler was shown by the value obtained by the following method. The closer the desorption rate of carbon black is to 0%, the smaller the desorption amount of carbon black from the particle surface is.

3 g of the black composite filling material and 40 m of ethanol
was placed in a 50 ml sedimentation tube, subjected to ultrasonic dispersion for 20 minutes, and allowed to stand for 120 minutes to separate a black composite filler material and desorbed carbon black due to a difference in specific gravity. Then
Ethanol (40 ml) was added to the black composite filling material again, ultrasonic dispersion was further performed for 20 minutes, and the mixture was allowed to stand for 120 minutes to separate the black composite filling material and the detached carbon black. The black composite filling material was dried at 100 ° C. for 1 hour, and the above-mentioned “Horiba Metal Carbon / Sulfur Analyzer EMIA-
The carbon content was measured using Model 2200 (manufactured by Horiba, Ltd.), and the value determined according to the following equation 1 was defined as the desorption rate (%) of carbon black.

[0106]

## EQU1 ## Desorption rate (%) of carbon black = {(Wa−
We) / Wa} × 100 Wa: Amount of carbon black attached to black composite filler We: Amount of carbon black attached to black composite filler after desorption test

The blackness of the black composite filler and the carbon black fine particles was 0.5 g for the sample and 0.7 m for castor oil.
and kneaded with a Hoover-type muller to form a paste. 4.5 g of clear lacquer is added to the paste, kneaded and made into a paint, and 150 μm (6 mil) is cast on a cast-coated paper.
Coating pieces (coating thickness:
About 30 μm). The paint piece was measured using a multi-source spectrophotometer MSC-IS-2D (manufactured by Suga Test Instruments Co., Ltd.), and the colorimetric index L ^* was determined according to JIS Z 8729 ^. Indicated by value.

Here, the L ^* value represents lightness, and the smaller the L ^* value, the better the blackness.

The specific volume resistance of each of the silica particle powder, the black composite filler and the tread rubber composition was determined by measuring the resistance of a sample prepared by the following method.

In the case of the silica particle powder and the black composite filling material, 0.5 g of the sample particle powder was weighed out, and measured using a KBr tablet press (Shimadzu Corporation) at 1.372 × 10 3
Press molding at a pressure of ⁷ Pa (140 Kg / cm ² )
A cylindrical sample to be measured was prepared. In the case of the tread rubber composition, a resin plate prepared by a method described below was punched out to prepare a cylindrical sample to be measured.

Next, after the sample to be measured was exposed to an environment of a temperature of 25 ° C. and a relative humidity of 60% for 12 hours or more, the sample to be measured was set between stainless steel electrodes, and a Wheatstone bridge (TYPE2768 Yokogawa Hokushin Electric Co., Ltd.) And a resistance R (Ω) was measured by applying a voltage of 15V.

Next, the area A (cm ² ) and the thickness t ₀ (cm) of the upper surface of the sample to be measured (cylindrical) were measured, and the measured values were inserted into the following equation 2 to obtain the volume resistivity ( Ω ・ c
m) was determined.

[0113]

## EQU2 ## Volume specific resistance (Ω · cm) = R × (A / t ₀ )

The light resistance of the black composite filler is shown below.
Cold rolled steel sheet with primary color enamel produced according to the method
(0.8mm x 70mm x 150mm) (JIS G-
3141) with a thickness of 150 μm and drying to form a coating film.
Half of the measurement sample obtained by forming
Cover with a foil made of metal
SUV-W13 "(Iwasaki Electric Co., Ltd.)
Irradiation intensity of 100mW / cm^TwoFor 6 hours
After that, cover the exposed part with a metal foil.
Color with the part that was not irradiated with UV light
(L^*Value, a^*Value, b ^*Value) is set to “Multi light source spectrophotometer MSC
-IS-2D "(manufactured by Suga Test Instruments Co., Ltd.)
UV light by measuring each and covering with metal foil
Based on the measured value of the part that was not irradiated,
Therefore, the calculated ΔE^*The values indicated lightfastness.

[0115]

ΔE ^* value = ((ΔL ^* value) ² + (Δa ^* value) ² +
(Δb ^* value) ² ) ^1/2 ΔL ^* value: Difference in L ^* value of the sample to be compared with / without UV irradiation Δa ^* value: Difference in a ^* value of the sample with / without UV irradiation Δb ^* value: Compare Difference of b ^* value of sample with and without UV irradiation

The primary color enamel was prepared by blending 10 g of the sample powder, 16 g of amino alkyd resin and 6 g of thinner, and adding 90 g of 3 mmφ glass beads to a 140 ml glass bottle.
After mixing and dispersing for 5 minutes, 50 g of an amino alkyd resin was added, and the mixture was further dispersed for 5 minutes using a paint shaker to produce a resin.

The light resistance of the tread rubber composition was measured by covering a half of a resin plate prepared by a processing method described later with a metal foil, and using an eye super UV tester SUV-
After continuously irradiating with UV light at an irradiation intensity of 100 mW / cm ² for 2 hours using “W13” (manufactured by Iwasaki Electric Co., Ltd.), a portion irradiated with the ultraviolet light and a portion not irradiated with the ultraviolet light by covering with a metal foil Hue (L ^* value,
a ^* value, b ^* value) were measured, and the light fastness was indicated by the ΔE ^* value calculated according to the above equation 3 based on the measurement value of a portion where the ultraviolet ray was not irradiated by covering with a metal foil.

The dispersibility in the tread rubber composition was evaluated by visually determining the number of undispersed aggregated particles on the surface of the obtained tread rubber composition, and evaluated on a scale of 1 to 5. 5 indicates that the dispersion state is the best.

[0119] 1: per 1 cm ² 50 or more 2: 1 cm less than 50 10 or more per ² 3: 1 cm less than 5 or 10 or more per ² 4: 1 cm 5 fewer than 1 or more per ² 5: No undispersed material found

The abrasion resistance of the tread rubber composition was measured using a Lambourn abrasion tester under the conditions of a load of 4.5 kg and a slip ratio of 50% in accordance with JIS K 6264. The value of the tread rubber composition was taken as 100, and the amount of wear loss was shown as an index. The larger the index of the wear loss amount, the better the wear resistance.

The tensile strength of the tread rubber composition is determined according to JIS.
The measurement was performed according to K6301. <Production of Black Composite Filling Material> Silica particle powder (particle shape: granular, average particle size 0.022 μm, BET specific surface area value 193.8 m ² / g, volume specific resistance value 3.6 × 10 ⁷ Ω)
330 cm of methyl hydrogen polysiloxane (trade name: TSF484: manufactured by GE Toshiba Silicone Co., Ltd.) was added to 11.0 kg of the silica particle powder while operating the edge runner, and 588 N / cm (60 K) was added.
g / cm) with a linear load of 40 minutes. The stirring speed at this time was 22 rpm.

Next, 11.0 kg of carbon black fine particles (particle shape: granular, particle size 0.022 μm, BET specific surface area value 134 m ² / g, blackness L ^* value 16.6)
Was added over 10 minutes while operating the edge runner, and further mixed and stirred for 80 minutes at a linear load of 588 N / cm (60 Kg / cm) to attach carbon black to the methylhydrogenpolysiloxane coating. Drying was performed at 105 ° C. for 60 minutes using a dryer to obtain a black composite filling material. The stirring speed at this time was 22 rpm.
I went in.

The obtained black composite filling material was granular particles having a particle size of 0.026 μm. The BET specific surface area is 124.2 m ² / g, and the volume resistivity is 7.4.
× 10 Ω · cm, light resistance ΔE ^* value is 2.4, blackness L ^* value is 17.0, carbon black desorption rate is 7.8%, and the coating amount of methyl hydrogen polysiloxane is S
It was 1.30% by weight in terms of i. The amount of the attached carbon black was 48.62% by weight in terms of C (corresponding to 100 parts by weight with respect to 100 parts by weight of the silica particle powder). From the observation result of the electron micrograph, it was confirmed that almost all of the carbon black was adhered to the methylhydrogenpolysiloxane coating since almost no carbon black was recognized.

<Manufacture of Tread Rubber Composition> The tread rubber composition was prepared by mixing and kneading the tread rubber composition in a mixing ratio shown below by a conventional method using a Banbury mixer and a kneading roll machine.

Styrene-butadiene copolymer 100.0 parts by weight Black composite filler 40.0 parts by weight Zinc white 3.0 parts by weight Stearic acid 2.0 parts by weight Antioxidant 2.0 parts by weight Wax 1.0 part by weight Parts Sulfur 1.8 parts by weight Vulcanization accelerator 0.8 parts by weight

The obtained tread rubber composition was press-vulcanized at 160 ° C. for 20 minutes to prepare test pieces, which were subjected to various tests.

The wear resistance of the obtained tread rubber composition was
110, electric resistance value is 3.2 × 10 ^ThreeΩ · cm, tensile strength
24.8MPa, light resistance ΔE^*The value is 0.38
In the tread rubber composition of the black composite filler
The dispersibility was 5.

[0128]

The most important point in the present invention is that the black composite filler in which carbon black is adhered to the particle surface of the silica particle powder via an organosilane compound or polysiloxane has a high blackness and has a fading property due to light. This is the fact that it is suppressed and has low volume resistivity and excellent dispersibility.

The reason why the black composite filler of the present invention has high blackness is that the present inventors use silica particles, which are extenders having no coloring power and no concealing power, as core particles and are also fine particles. Then, the carbon black fine particle powder, which normally behaves as an aggregate, can be uniformly and densely attached to the particle surface of the silica particles via an organosilane compound or polysiloxane generated from alkoxysilane, so that the carbon black to be attached is It is considered that the color was developed without canceling the blackness by the hue of the core particles.

Regarding the reason why the discoloration due to light of the black composite filling material according to the present invention is suppressed, the present inventor reported that silica particle powder was coated with an organosilane compound or polysiloxane having excellent light resistance, and It is considered that the surface activity of the silica particle powder was suppressed by coating with an organosilane compound or polysiloxane.

The present inventor considers the reason why the black composite filler according to the present invention is excellent in dispersibility in a tread rubber composition as follows. Silica particle powder has hydrophilicity due to having a silanol group on the particle surface, has low compatibility with rubber generally used for tires, and has hydrogen of the silanol group. The particles tend to agglomerate due to bonding, and uniform dispersion in a rubber composition such as a tire was difficult, but excellent dispersibility in the rubber composition such as a tire on the particle surface of the silane particle powder. That the carbon black is adhered through an organosilane compound or polysiloxane to improve compatibility with the rubber component used in the tread rubber composition and to remove carbon from the particle surface of the black composite filler material It is considered that the dispersion in the system is not hindered by carbon black due to the small amount of black.

Regarding the reason why the tread rubber composition according to the present invention has excellent light resistance, the present inventor has found that the black composite filler material according to the present invention used as a filler for tread rubber has excellent light resistance. I believe it is due to

Regarding the reason why the tread rubber composition according to the present invention has a low electric resistance value, the present inventor has found that the black composite filling material according to the present invention used as a filler for a tread rubber is high. It is thought to be due to having conductivity.

Regarding the reason why the tread rubber composition according to the present invention has excellent abrasion resistance and tensile strength, the present inventor has proposed that the black composite filling material according to the present invention is used in the tread rubber composition. It is thought that it could be dispersed more uniformly inside.

[0135]

Next, examples and comparative examples will be described.

Core Particles 1 to 3: Various silica particle powders having the properties shown in Table 1 were prepared as core particles.

[0137]

[Table 1]

Core particle 4: A slurry containing the silica particle powder was obtained by using 20 kg of the silica particle powder in which the aggregation of the core particle 1 was disentangled and 150 l of water. The pH value of the dispersion slurry containing the obtained silica particle powder was adjusted to 10.5 using an aqueous sodium hydroxide solution, and then water was added to the slurry to adjust the slurry concentration to 98 g / l. The slurry (150 l) was heated to 60 ° C., and a 1.0 mol / l NaAlO ₂ solution 2722 m
1 (corresponding to 0.5% by weight in terms of Al with respect to the silica particle powder) was added, and after maintaining for 30 minutes, the pH value was adjusted to 7.5 using acetic acid. After maintaining in this state for 30 minutes, filtration, washing with water, drying and pulverization were carried out to obtain silica particle powder whose particle surface was coated with aluminum hydroxide.

Table 2 shows the production conditions and various properties of the obtained surface-treated silica particles.

Core particles 5 and 6: The particle surfaces are coated with the intermediate coating in the same manner as the core particles 4 except that the core particle powder and the type and amount of the intermediate coating are variously changed. A silica particle powder was obtained.

Table 2 shows the production conditions and various properties of the obtained surface-treated silica particle powder. The type A of the coating in the surface treatment step represents an aluminum hydroxide.

[0142]

[Table 2]

Examples 1 to 6, Comparative Examples 1 to 3: Types of core particles, presence or absence of addition of alkoxysilane or polysiloxane,
The invention described above except that the kind and amount of addition, the treatment conditions by the edge runner in the coating step with alkoxysilane or polysiloxane, the kind and amount of the carbon black fine particle powder, and the treatment conditions by the edge runner in the carbon black adhesion step were variously changed. A black composite filling material was obtained in the same manner as in the embodiment. In the black composite filler obtained in each of Examples 1 to 6, the result of electron microscopic observation shows that almost no carbon black is recognized, so that almost all of the carbon black is an organosilane compound generated from alkoxysilane or Adhesion to the polysiloxane compound coating was observed.

Table 3 shows the properties of the carbon black fine particle powders A to C used.

[0145]

[Table 3]

Table 4 shows the main processing conditions at this time, and Table 5 shows various properties of the obtained black composite filler.

[0147]

[Table 4]

[Table 5]

Comparative Example 4 (Japanese Patent No. 3160552)
Additional Test Experiment of Example 1): Using the silica particle powder of the core particles 1 in a rotary continuous heating furnace, the inside of the system was sufficiently replaced with nitrogen to reduce the oxygen concentration to 0.3% by volume or less, and then together with nitrogen gas. While propane gas was flowed at a volume mixing ratio of 10: 1 (nitrogen gas / propane gas), the inside of the system was heated to 900 ° C., and the propane gas was thermally decomposed to form a carbon layer on the particle surface of the silica particle powder. . The coating amount of the carbon layer was 20 parts by weight based on 100 parts by weight of the silica particle powder.

Table 5 shows the properties of the obtained black silica particle powder.

Example 7: 20 g of calcium stearate was added to 2 kg of the black composite filling material, and the temperature was raised to 120 ° C. over 30 minutes while stirring using a Henschel mixer. The surface-coated black composite filler was obtained by cooling to room temperature over a period of minutes.

The production conditions at this time are shown in Table 6, and various properties of the obtained surface-coated black composite filler are shown in Table 7.

Examples 8 and 9: Except that the kind of the black composite filling material, the kind and the amount of the fatty acid, the fatty acid metal salt and the coupling agent and the amount of coating, and the kneading temperature and the kneading time in the coating step using the Henschel mixer were variously changed, In the same manner as in Example 7, a black composite filling material in which the particle surfaces were covered with the coating material was obtained.

The production conditions at this time are shown in Table 6, and various properties of the obtained surface-coated black composite filler are shown in Table 7.

[0154]

[Table 6]

[0155]

[Table 7]

Examples 10 to 18 and Comparative Examples 5 to 10: A tread rubber composition was obtained in the same manner as in the embodiment of the invention except that the kind of the filler was changed variously.

Table 8 shows the production conditions and various properties of the obtained tread rubber composition.

[0158]

[Table 8]

[0159]

The black composite filler according to the present invention has a high blackness, suppresses fading due to light, and has a low volume resistivity and excellent dispersibility. It is suitable as a material filler.

Further, the rubber composition in which the above-mentioned black composite filling material is blended with rubber has a low level of fading due to light, and has a low electric resistance value and excellent abrasion resistance and tensile strength. Therefore, it is suitable as a tread rubber composition.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hiroko Morii 1-4, Meiji Shinkai, Otake City, Hiroshima Prefecture Toda Kogyo Co., Ltd. Otake Creative Center F term (reference) 4J002 AC011 AC031 AC061 AC071 AC081 AC091 BB151 BB181 BG041 DA037 FB076 FB096 FB236 FD016 4J037 AA18 CA02 CA12 CA23 CA24 CB09 CB23 CC28 DD05 DD11 EE03 EE04 FF05 FF11 FF15 FF17 FF18 FF22

Claims (4)

[Claims] An average particle diameter of a silica particle powder in which an organosilane compound or a polysiloxane formed from an alkoxysilane is coated on the particle surface and carbon black is adhered to at least a part of the coating.
A composite silica particle powder having a particle size of from 0.1 to 0.5 μm, wherein
A black composite filling material characterized by being 1 to 1000 parts by weight based on parts by weight. 2. A black composite filling material, wherein the particle surface of the composite silica particle powder according to claim 1 is coated with a fatty acid, a fatty acid metal salt or a coupling agent. 3. The particle surface of the silica particle powder according to claim 1 or 2, wherein the particle surface is selected from at least one of aluminum hydroxide, aluminum oxide, silicon hydroxide and silicon oxide. Black composite filling material, characterized by being coated with an intermediate coating. 4. A tread rubber composition using the black composite filler according to any one of claims 1 to 3.