JP2014234468A - Rubber composition and tire prepared using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition which provides a tire having improved reduced rolling resistance and wear resistance at high levels by combining a specific rubber component with a specific carbon black, and a tire prepared using the same.SOLUTION: According to a rubber composition of the present invention, a natural rubber to be used is one obtained by hydrolysis of phospholipid, for example, hydrolysis by enzyme treatment of lipase and/or phospholipase, and obtained by blending high hydrogen carbon black with the rubber composition. There is also provided a tire prepared using the rubber composition.

Description

  The present invention relates to a rubber composition and a tire using the same, and more specifically, a rubber composition in which low heat buildup and wear resistance are improved by blending natural rubber hydrolyzed with specific carbon black. The present invention relates to a thing and a tire using the same.

  In recent years, there has been an increase in demands for fuel efficiency reduction of automobiles in connection with the global movement of regulation of carbon dioxide emissions due to increasing interest in environmental issues, and tires are also required to reduce fuel consumption, that is, reduce rolling resistance. It has been. In order to reduce rolling resistance in a tire, a general method is to use a rubber composition having low heat generation.

  The rubber composition usually contains carbon black for rubber. Carbon black improves the performance of the compounded rubber composition by its physicochemical characteristics, that is, the unit particle diameter, the surface area per unit mass (specific surface area), the degree of particle connection (structure), and the surface properties. It has a big impact. For this reason, carbon black having different characteristics is selectively used depending on required rubber performance, environment in which it is used, and the like. In particular, rubber compositions used for tires are excellent in wear resistance (wear resistance) due to contact with the road by rotating at a high speed, and at the same time, repeated deformation of the rubber composition caused by contact with the road surface. It is an important factor to reduce the hysteresis loss characteristic due to (low heat generation property). However, wear resistance and low heat build-up are mutually contradictory characteristics. In order to solve this problem, carbon black having various characteristics has been proposed.

Natural rubber is also frequently used in many fields such as industrial equipment such as tires, rubber belts, rubber rolls, priders, and fenders, and sporting goods such as tennis balls, basketball, soccer balls, and volleyball. It is also frequently used in the bio field. Further, in tires, it is used as a material for all components constituting rubber tires such as treads, sidewalls, ply coating rubbers, and bead fillers.
In recent years, it has been proposed that natural rubber latex be chemically or enzymatically treated to decompose or remove components other than rubber components contained in natural rubber, thereby improving the properties of natural rubber (reducing exothermic properties). Has been.

  For example, it has been proposed to chemically reduce the total nitrogen amount in natural rubber (see Patent Document 1) and to repeat saponification and washing in order to reduce the amount of phosphorus in natural rubber (Patent Document 2). Patent Document 3 and Patent Document 4).

  To further improve wear resistance and low heat build-up in recent years, further improve wear resistance and low heat build-up by combining natural rubber and reinforcing filler, especially specific carbon black, whose characteristics are not reduced. There is a need for rubber compositions and tires that can be used.

JP-A-6-329838 JP 2010-174169 A JP 2010-138360 A JP 2010-138359 A

  The present invention provides a rubber composition that gives a tire having a high level of reduction in rolling resistance and wear resistance by combining a rubber component and a specific carbon black, and a tire using the rubber composition. Objective.

In the present invention, phospholipid is hydrolyzed by binding to the end of a natural rubber molecule, and the high hydrogen carbon black sufficiently exhibits affinity and binding to the hydroxyl group generated at the end of the hydrolyzed portion of the phospholipid. Thus, the above object is achieved.
The present invention uses natural rubber as a rubber component, further hydrolyzes the phospholipid bonded to the end of the natural rubber molecule, and is reactive with the hydroxyl group generated at the end of the hydrolyzed portion of the phospholipid. By giving affinity to and binding to high hydrogen carbon black, and making natural rubber reactive without compromising the quality of natural rubber such as aging resistance, and using it with high hydrogen carbon black The above-mentioned purpose has been achieved.
That is, the rubber composition of the present invention is characterized in that high hydrogen carbon black is blended with natural rubber obtained by hydrolyzing phospholipids of natural rubber molecules.

Natural rubber obtained by hydrolyzing phospholipids is expected to have affinity with high hydrogen carbon black and bonding properties such as radical bonding and hydrogen bonding. From the viewpoint of not impairing the original properties of natural rubber, an enzyme-treated phospholipid is preferable because it does not impair the properties of natural rubber while exhibiting affinity and binding properties with high hydrogen carbon black. .
In the natural rubber phospholipid hydrolysis treatment, phospholipid ester bonds in the natural rubber raw latex are released to separate fatty acids such as oleic acid and palmitic acid. The ester decomposition treatment of the phospholipid in the latex can be a chemical treatment, but an enzyme treatment of lipase and / or phospholipase is preferable.

In the hydrolysis of phospholipids in natural rubber, it is preferable that phospholipids in natural rubber are degraded by 50% or more, more preferably 70% or more, and even more preferably 85% or more. This is because the hydrous silicic acid having a specific structure exhibits sufficient affinity and binding to natural rubber. The undegraded phospholipid of the natural rubber is preferably 0.66 wt% or less, more preferably 0.4 wt% or less, and further preferably 0.3 wt% or less.
In the hydrolysis treatment of natural rubber, it is preferable to use a natural rubber latex that is adjusted to pH 7 or more within 1 hour after collection.
The degradation amount (%) of phospholipid is determined by setting an index of reactivity (indicating an increase in fatty acid in a latex solution of fatty acid generated by ester decomposition from phospholipid as an index).
In addition, the enzyme treatment is preferably performed at an optimum pH and an optimum temperature. In the present invention, the pH is preferably 5 or more and 11 or less, and is preferably 70 ° C. or less. If necessary, it is preferable to treat with a surfactant in addition to the enzyme treatment.

The high hydrogen carbon black used in the present invention is a carbon black having a specific property obtained by a specific process.
That is, using a reactor in which a combustion gas generation zone, a reaction zone, and a reaction stop zone are connected in series, high-temperature combustion gas is generated in the combustion gas generation zone, and then the raw material is sprayed into the reaction zone Then, after forming a reaction gas flow containing carbon black, the reaction gas flow is rapidly cooled by a multistage rapid refrigerant introduction means in the reaction stop zone to terminate the reaction.
In order to obtain a high hydrogen carbon black, the following relational expressions (1) and (2)
10 <X <40 (1)
90 <Z <100 (2)
(However, X represents the toluene coloring permeability (%) of carbon black after introduction of the first quenching medium from the raw material introduction position, and Z represents the toluene coloring permeability of carbon black after the last quenching medium introduction ( %).)).

In addition, the residence time in the zone from when the raw material is sprayed into the reaction zone until the first quenching medium is introduced is t ₁ (seconds), and the average reaction temperature in this zone is T ₁ (° C.). The residence time in the zone from the introduction of the first quenching medium to the introduction of the second quenching medium is t _{2 (} seconds), and the average reaction temperature in this zone is T ₂ (° C.). Furthermore, the residence time in the zone from the introduction of the second quenching medium to the introduction of the last quenching medium is t ₃ (seconds), and the average reaction temperature in this zone is T ₃ (° C. ), The following relational expressions (3), (4) and (5)
2.00 ≦ α1 ≦ 5.00 (3)
5.00 ≦ α2 ≦ 9.00 (4)
−2.5 × (α1 + α2) + 85.0 ≦ β ≦ 90.0 (5)
(However, α1 = t ₁ × T ₁ , α2 = t ₂ × T ₂ , β = t ₃ × T _3. )
It is preferable to obtain high hydrogen carbon black by controlling so as to satisfy.

Further, the high hydrogen carbon black has the following relational expressions (6), (7) and (8):
20 <X <40 (6)
50 <Y <60 (7)
90 <Z <95 (8)
(In the formula, Y represents the toluene coloring permeability of carbon black after introduction of the second quenching medium, and X and Z are the same as described above.)
It is preferable that it is obtained by controlling so as to satisfy.

The hydrogen release rate of the high hydrogen carbon black of the present invention is preferably 0.30% by mass or more. Usually, the carbon black obtained by the conventional method is about 0.15% by mass, but the one obtained by introducing the above-mentioned rapid refrigerant body has a high hydrogen release rate and has an affinity with the natural rubber. , Fully exhibits binding. Therefore, when such carbon black is blended in a rubber composition, a rubber composition in which wear resistance and low heat build-up (low rolling resistance) are balanced at a high level can be provided.
Further, high hydrogen carbon black having a DBP absorption amount of 95 to 220 mL / 100 g, a 24M4 DBP absorption amount of 90 to 200 mL / 100 g, and a CTAB adsorption specific surface area of 70 to ²⁰⁰ m ² / g is preferable in view of the above effects.

In such a rubber composition of the present invention, it is preferable to contain 10% by mass or more of natural rubber with respect to the total amount of the rubber component, and 10% of high hydrogen carbon black is added to 100 parts by mass of the rubber component. It is preferable to contain in the ratio of -250 mass parts.
Furthermore, this invention also provides the tire which uses a rubber composition.

    According to the rubber composition according to the present invention, the ester bond in the phospholipid of natural rubber is hydrolyzed to generate a hydroxyl group at the end, and in particular, it is selectively hydrolyzed by enzymatic treatment, so that the natural rubber has The stable characteristics are not impaired, and the generation of this hydroxyl group improves the affinity with the high hydrogen carbon black, and causes the bonding such as radical bonding and hydrogen bonding. As a result, the rubber composition of the present invention The tire obtained by using is excellent in oxidation aging resistance and abrasion resistance, and rolling resistance is improved.

It is the figure which showed the decomposition reaction of the phospholipid in the natural rubber latex decomposed | disassembled by a phospholipase process. It is a graph of the reactivity parameter | index which shows the increase amount of the fatty acid in the latex produced by enzymatic decomposition with respect to the enzyme amount shown in FIG. FIG. 2 is a chart of FT-IR showing a decrease in ester bond and an increase in fatty acid in latex caused by the enzymatic degradation of FIG. 1. It is a partial longitudinal front explanatory drawing of an example of the carbon black manufacturing furnace for manufacturing high hydrogen carbon black.

  The rubber composition of the present invention comprises natural rubber obtained by hydrolyzing phospholipids of natural rubber molecules and high hydrogen carbon black.

<Natural rubber>
The natural rubber used in the present invention is obtained by hydrolyzing a phospholipid bonded to the natural rubber, and the hydrolysis is for treating a latex of the natural rubber.
As shown in FIG. 1, the natural rubber molecule contains phospholipid. Phospholipids produce free fatty acids such as oleic acid and palmitic acid by ester decomposition.
As shown in FIG. 2, in the hydrolysis, the amount of fatty acid generated by the decomposition is set as an index of phospholipid decomposition reactivity.
As shown in FIG. 3, the amount of fatty acid in the latex solution generated by enzyme degradation is determined by measuring the peak amount of [—COOH] in the vicinity of 1710 [cm ⁻¹ ] using an FT-IR measuring device (manufactured by Varian). .

The index of reactivity is set by measuring the amount of initial fatty acid in the raw latex solution used in advance, and setting this value as the phospholipid decomposition rate of 0%. The latex solution contains 100 mass of latex as the solid content of natural rubber. Phospholipase is added at a ratio of 0.1, 0.2, 0.5, 1.0, and 5.0 parts by mass, respectively. As shown in FIG. 3, the amount of change in the fatty acid peak in the latex solution after the reaction was measured, and as shown in FIG. 2, the maximum amount of fatty acid was determined from the change in the amount of fatty acid in the reference curve. The decomposition rate of phospholipid is 100%. In the estimation of the maximum value, a value at an infinite enzyme addition amount is estimated based on the reference curve characteristic.
Therefore, the degradation rate (%) of phospholipid in the natural rubber as a raw material = {(measured fatty acid amount) − (initial fatty acid amount)} / {(maximum fatty acid amount set as an index) − (initial fatty acid amount)} × 100. The amount of undegraded phospholipid (based on the amount of fatty acid) (wt%) in the raw latex (100 g) is (maximum fatty acid amount g) − (initial fatty acid amount g), and after the predetermined reaction treatment The amount (wt%) of undegraded phospholipid in the latex is (maximum fatty acid amount g) − (measured fatty acid amount g).
Here, 2000 LEN / g (Novozyme standard unit) phospholipase (manufactured by Novozyme) was used as the enzyme used in the index setting. The reaction conditions were such that a latex solution having a latex solid content concentration of 20 wt% was used, the pH was set to 8, and the reaction was performed at room temperature (25 ° C.) for 16 hours.

The natural rubber latex used as a raw material means a field latex obtained from a natural rubber tree, and either a commercially available ammonia-treated latex or a fresh field latex can be used as the latex.
In the present invention, the latex is preferably adjusted to pH 7 or more within 1 hour after collection. When such a latex is used, it is easy to uniformly disperse the added enzyme in the latex solution.

Examples of the enzyme that degrades phospholipids of natural rubber include lipase and / or phospholipase used as a measurement index as described above.
The lipase and phospholipase are not particularly limited, and any of those derived from bacteria, those derived from filamentous fungi, and those derived from yeast may be used. Moreover, lipase and phospholipase are international unit 100 (U / g) or more, preferably 1000 (U / g) or more, more preferably 10,000 (U / g) or more, and further preferably 100,000 (U / g) or more. That is good. Examples of such lipases and phospholipases include commercially available NS44151 (a product manufactured by Novozyme), lipase M “Amano” 10 (a product manufactured by Amano Enzyme Co., Ltd.), lipase OF (a product manufactured by Meika Inc.), phospholipase A1. (Product of Sankyo Co., Ltd.).
In addition, in the use of the above-described indicator enzyme, it is preferable to use an enzyme having a purity of 2000 LEN / g (Novozyme standard unit) or higher phospholipase (manufactured by Novozyme) or higher.
The amount of lipase and / or phospholipase added during such enzyme treatment is in the range of 0.01 to 10 parts by weight, particularly 0.1 to 5 parts by weight, based on 100 parts by weight of the solid component in the natural rubber latex. It is preferable. If the addition amount is in the above range, a decomposition rate of 50% or more of the phospholipid in the natural rubber latex can be achieved.

The natural rubber used in the present invention may be further subjected to an enzyme treatment with a protease in addition to lipase and / or phospholipase.
Like the lipase and phospholipase, the protease is not particularly limited, and may be any of bacteria, filamentous fungi, or yeast. Further, the titer of the protease is preferably 100 (U / g) or more, preferably 1000 (U / g) or more, more preferably 10,000 (U / g) or more, and further preferably 100,000 (U / g). That is good. Examples of such proteases include commercially available Alcalase 2.5L-type DX (manufactured by Novozymes), pro leather FG-F (manufactured by Amano Enzymes) and the like.
In the present invention, in addition to the above-mentioned enzymes, peptidase, cellulase, pectinase, esterase, amylase and the like can be used in combination.

In addition, when such an enzyme is added, other additives such as phosphates such as potassium phosphate, potassium phosphate and sodium phosphate, and acetates such as potassium acetate and sodium acetate as pH adjusters. Furthermore, acids such as sulfuric acid, acetic acid, hydrochloric acid, nitric acid, citric acid and succinic acid or salts thereof, or ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate and the like can be used.
In the present invention, the enzyme treatment is preferably performed at an optimum pH, but considering the dispersibility in latex, pH 5 to 11 is preferable, and pH 7 to 10 is particularly preferable.

In the present invention, the enzyme treatment is performed at a temperature of 70 ° C. or less, preferably at a temperature of 60 ° C. or less, more preferably at 50 ° C. or less.
When the enzyme treatment temperature exceeds 70 ° C., the stability of the natural rubber latex decreases, and the latex coagulates during the enzyme treatment. After coagulation, the degradation effect by the enzyme decreases. For this reason, it becomes difficult to produce natural rubber having excellent processability.
When the enzyme treatment temperature exceeds 70 ° C., the stability of the natural rubber latex decreases, and the latex coagulates during the enzyme treatment. After coagulation, the degradation effect by the enzyme decreases. For this reason, it becomes difficult to produce natural rubber having excellent processability.

  In the present invention, the enzyme treatment time is 12 hours or longer, more preferably 16 hours or longer and 48 hours or shorter. With such a reaction time, the phospholipid in the latex is sufficiently decomposed. Phospholipid degradation is 50% or more, more preferably 70% or more, and still more preferably 80% or more. For this reason, if it is the said preferable processing time, reaction can fully be achieved.

The natural rubber latex according to the present invention is preferably treated in combination with the enzyme treatment and a surfactant. As the surfactant, nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants and the like can be used. In particular, nonionic surfactants and anionic surfactants can be used. It is preferable to use an agent or the like.
As the nonionic surfactant, for example, polyoxyalkylene ether, polyoxyalkylene ester, polyhydric alcohol fatty acid ester, sugar fatty acid ester, and alkyl polyglycoside are suitable.
As the anionic surfactant, for example, carboxylic acid type, sulfonic acid type, sulfuric acid ester type, and phosphoric acid ester type are suitable.
Examples of the carboxylic acid surfactant include fatty acid salts, polyvalent carboxylates, rosinates, dimer salts, polymer acid salts, tall oil fatty acid salts, and the like. Examples of the sulfonic acid surfactant include alkylbenzene sulfonate, alkyl sulfonate, alkyl naphthalene sulfonate, naphthalene sulfonate, and diphenyl ether sulfonate. Examples of sulfate surfactants include alkyl sulfates, polyoxyalkylene alkyl sulfates, polyoxyalkylene alkyl phenyl ether sulfates, tristyrenated phenol sulfates, polyoxyalkylene distyrenated phenol sulfates. Etc. Examples of phosphate ester surfactants include alkyl phosphate ester salts and polyoxyalkylene phosphate ester salts.

  The natural rubber latex treated with the enzyme as described above coagulates without completely separating non-rubber components. When the non-rubber component is separated, the aging resistance is poor. The rubber component obtained by coagulating the treated latex is washed and then dried using a normal dryer such as a vacuum dryer, air dryer, drum dryer or the like, whereby the natural rubber used in the present invention can be obtained. .

<High hydrogen carbon black>
The high hydrogen carbon used in the present invention uses a reaction apparatus in which a combustion gas generation zone, a reaction zone, and a reaction stop zone are connected in series, and generates high-temperature combustion gas in the combustion gas generation zone, After the raw material is sprayed and introduced into the reaction zone to form a reaction gas flow containing carbon black, the reaction gas flow is quenched in the reaction stop zone by a multistage rapid refrigerant introduction means to terminate the reaction. And is manufactured as follows.

The interior of the carbon black production furnace has a structure in which a combustion zone, a reaction zone, and a reaction stop zone are connected, and the whole is covered with a refractory.
The carbon black production furnace uses a rectifying plate to rectify the oxygen-containing gas introduced from the outer periphery of the furnace head and the oxygen-containing gas introduction pipe into the flammable fluid introduction chamber as a combustion zone. An oxygen-containing gas introduction cylinder to be introduced, and a fuel oil spraying device introduction pipe installed on the central axis of the oxygen-containing gas introduction cylinder and introducing the hydrocarbon for fuel into the combustible fluid introduction chamber. In the combustion zone, high-temperature combustion gas is generated by combustion of hydrocarbons for fuel.

   The carbon black production furnace includes a reaction chamber in which a cylinder gradually converges, a raw material oil introduction chamber including, for example, four raw oil spray ports on the downstream side of the convergence chamber, and a reaction chamber on the downstream side of the raw material oil introduction chamber. With. The feed oil spray port sprays feed hydrocarbons into the hot combustion gas stream from the combustion zone. In the reaction zone, the raw material hydrocarbon is sprayed into the high-temperature combustion gas stream, and the raw material hydrocarbon is converted into carbon black by incomplete combustion or thermal decomposition reaction.

FIG. 4 is a partially longitudinal front explanatory view of an example of a carbon black production furnace for producing the high hydrogen carbon black, and a reaction chamber into which a high-temperature gas containing a carbon black raw material (raw material hydrocarbon) is introduced. 10 and the reaction continuation / cooling chamber 11 are shown. As shown in FIG. 4, the carbon black production furnace 1 includes a reaction continuation / cooling chamber 11 having a multistage rapid refrigerant introduction means 12 as a reaction stop zone. The multistage rapid refrigerant introduction means 12 sprays a rapid refrigerant such as water on the high-temperature combustion gas flow from the reaction zone. In the reaction stop zone, the high-temperature combustion gas flow is quenched by the quenching refrigerant to terminate the reaction.
The carbon black production furnace 1 may further include a device for introducing a gas body in the reaction zone or the reaction stop zone. Here, as the “gas body”, air, a mixture of oxygen and hydrocarbon, a combustion gas obtained by a combustion reaction thereof, or the like can be used.
In this way, in the production of carbon black, the average reaction temperature and residence time in each zone until the reaction gas flow enters the reaction stop zone are controlled, and the toluene color permeability X, Y and Z are set to desired values. As a result, the high hydrogen carbon black used in the present invention is obtained.

More specifically, the combustion zone is a region where a hot gas flow is generated by the reaction of fuel and air, and this downstream end is the point where feedstock is introduced into the reactor (at multiple locations). When it is introduced, it indicates the most upstream side), for example, the upstream side (left side in FIG. 4) from the point where the feedstock is introduced.
The reaction zone refers to the multistage quench water spray means 12 in the reaction continuation / cooling chamber 11 from the point where the raw material hydrocarbon is introduced (the most upstream in the case of a plurality of positions) (these means are the reaction continuation / cooling chamber). 11 can be inserted and removed freely, and the use position is selected according to the type of product to be produced and the characteristics thereof) to the point of operation (introducing a cooling medium such as water). That is, for example, when the raw material oil is introduced at the third raw material oil spray port and water is introduced by the multistage rapid refrigerant introduction means 12, the region between these becomes the reaction zone. The reaction stop zone refers to a zone below (on the right side in FIG. 5) below the point where the quench water injection spray means is operated.

In FIG. 4, the name of the reaction continuation / cooling chamber 11 is used because the reaction zone is from the raw material introduction time to the operation time of the quenching water injection spraying means for stopping the reaction, and the reaction stop zone is thereafter. This is because the cold water introduction position may move depending on the required carbon black performance.
The high hydrogen carbon black thus obtained has the following relational expressions (1) and (2):
10 <X <40 (1)
90 <Z <100 (2)
It is necessary to satisfy.
X represents the toluene coloring permeability (%) of carbon black after the rapid refrigerant introduction from the first rapid refrigerant introduction means (12-X in FIG. 4) from the raw material introduction position, and Z is the last 4 shows the toluene coloring permeability (%) of carbon black after the rapid refrigerant body is introduced by the rapid refrigerant body introducing means (12-Z in FIG. 4). That is, the first carbon black after introduction of the quenching medium has a toluene color permeability higher than 10% and less than 40%, and the carbon black (high hydrogen carbon black) after the last quenching process is introduced is toluene. The color transmission needs to be higher than 90% and less than 100%. If the high-hydrogen carbon black has a toluene-colored transmittance of 90% or less, the carbon black has a large amount of heavy tar component contained therein, and can give sufficient reinforcement to rubber. This is not possible and wear resistance is reduced.
Further, when X is 40 or more, the reinforcing property of the carbon black is lowered and the wear resistance is lowered.

The high hydrogen carbon black having such properties can be obtained by controlling the reaction temperature and residence time as described below.
That is, the residence time in the zone from when the raw material is sprayed into the reaction zone until the first quenching medium is introduced is t ₁ (seconds), and the average reaction temperature in this zone is T ₁ (° C.). And the residence time in the zone from the introduction of the first quenching medium to the introduction of the quenching medium by the second quenching medium introducing means (12-Y in FIG. 4) is t ₂ (seconds). The average reaction temperature in this zone is T ₂ (° C.), and the residence time in the zone from the introduction of the second sudden refrigerant body to the introduction of the last sudden refrigerant body (that is, the reaction stop zone) When the residence time in the zone until passage is t ₃ (seconds) and the average reaction temperature in this zone is T ₃ (° C.), the following relational expressions (3), (4) and (5)
2.00 ≦ α1 ≦ 5.00 (3)
5.00 ≦ α2 ≦ 9.00 (4)
−2.5 × (α1 + α2) + 85.0 ≦ β ≦ 90.0 (5)
(However, α1 = t ₁ × T ₁ , α2 = t ₂ × T ₂ , β = t ₃ × T _4. )
By controlling to satisfy the above, the high hydrogen carbon black can be obtained.

The carbon black production furnace 1 has a structure in which thermocouples can be inserted into an arbitrary number of locations in order to monitor the temperature in the furnace. To calculate the average reaction temperature _{T 1,} T 2, _{T 3,} at each step (each band), at least two positions, preferably it is preferable to measure the temperature of 3-4 points.
Further, the residence times t ₁ , t ₂ , and t ₃ are calculated by calculating the volume of the introduced reaction gas fluid by a known thermodynamic calculation method and calculating by the following formula. Note that the increase in volume due to the decomposition reaction of the feedstock oil and the rapid cooling medium is ignored.
Residence time t1 (sec) =
{Reactor passing volume from raw material hydrocarbon introduction position to first quenching medium introduction position (m ³ ) / reaction gas fluid volume (m ³ / sec)}
Residence time t ² (sec) =
{Reactor passing volume (m ³ ) / volume of reaction gas fluid (m ³ / sec) from introduction of first quenching medium to introduction of second quenching medium}
Residence time t ³ (sec) =
Reactor passing volume (m ³ ) / reaction gas fluid volume (m ³ / sec) from the second quenching medium introduction position to the time when the last quenching medium is introduced

Further, as the high hydrogen carbon black, the following relational expressions (6), (7) and (8)
20 <X <40 (6)
50 <Y <60 (7)
90 <Z <95 (8)
(In the formula, Y represents the toluene coloring permeability of carbon black after introduction of the second quenching medium, and X and Z are the same as described above.)
What was obtained by controlling to satisfy | fill can be used suitably.
The toluene coloring transmittance is measured by the method described in Method B of Item 8 of JIS K 6218: 1997, and is expressed as a percentage with pure toluene.

The high hydrogen carbon black preferably has a hydrogen release rate exceeding 0.3% by mass. When this hydrogen release rate exceeds 0.3% by mass, the rubber composition of the present invention has high wear resistance and low heat generation. The hydrogen release rate is preferably 0.35% by mass or more. The upper limit is usually about 0.4% by mass.
The hydrogen release rate is as follows: (1) a carbon black sample is dried in a constant temperature dryer at 105 ° C. for 1 hour, cooled to room temperature in a desiccator, and (2) about 10 mg is added to a tubular tube sample container made of tin. Weigh accurately, crimp and seal, and (3) measure the amount of hydrogen gas generated when heated at 2000 ° C for 15 minutes under an argon stream with a hydrogen analyzer (Horiba EMGA621W), and display the mass fraction. .

Further, the high hydrogen carbon black has a dibutyl phthalate absorption (DBP) of 95 to 220 mL / 100 g, a compressed DBP absorption (24M4DBP) of 90 to 200 mL / 100 g, and a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 70 to What is 200 m < ² > / g is preferable.
The dibutyl phthalate absorption amount (DBP) and the compressed DBP absorption amount (24M4DBP) are measured by the method described in ASTM D2414-88 (JIS K6217-4: 2001) and are absorbed per 100 g of carbon black. DBP) in mL. The cetyltrimethylammonium bromide adsorption specific surface area (CTAB) is measured by the method described in JIS K6217-3: 2001, and is expressed as a specific surface area m ² / g per unit mass of carbon black.

<Rubber composition>
The rubber composition of the present invention preferably contains 10% by mass or more, particularly 30% by mass or more of the above natural rubber with respect to the total amount of the rubber component. By including the natural rubber, the effect of the high hydrogen carbon black is sufficiently enhanced.
As the rubber component, polybutadiene rubber, styrene-butadiene copolymer rubber, synthetic isoprene rubber, ethylene-propylene-diene rubber, chloroprene rubber, and the like can be included in addition to the natural rubber.

Moreover, it is preferable to contain high hydrogen carbon black in the ratio of 10-250 mass parts with respect to 100 mass parts of rubber components.
A rubber composition containing high hydrogen carbon black in such a range has desired physical properties such as wear resistance and low rolling resistance. Furthermore, the content of the high hydrogen carbon black is preferably 20 to 150 parts by mass, and more preferably 30 to 120 parts by mass with respect to 100 parts by mass of the rubber component.
The high hydrogen carbon black is manufactured by the above-described method and has the above-described physical properties. Examples of the carbon black include FEF, SRF, HAF, ISAF, ISAF-LS, SAF-LS. And so on.
In addition to the rubber component and high hydrogen carbon black, the rubber composition of the present invention includes other components such as carbon black other than high hydrogen carbon black, inorganic fillers, vulcanizing agents, vulcanization accelerators, zinc oxide, stearin. A compounding agent usually used in the rubber industry such as an acid and an anti-aging agent can be appropriately selected and compounded within a range not impairing the object of the present invention. As these compounding agents, commercially available products can be suitably used. The rubber composition is prepared by blending a rubber component, high hydrogen carbon black, and various appropriately selected compounding agents, kneading using a Banbury mixer, roll, internal mixer, intensive mixer, etc. It can be prepared by placing, extruding and the like.

<Tire>
The tire of the present invention is characterized in that the rubber composition is applied to any of tire members. Here, in the tire of the present invention, it is particularly preferable to use the rubber composition of the present invention for a tread. The tire using the rubber composition for a tread has excellent wear resistance and low rolling resistance and low fuel consumption. Excellent in properties. In addition, as gas with which the tire of the present invention is filled, normal or air with a changed oxygen partial pressure, or an inert gas such as nitrogen is exemplified. When the rubber composition of the present invention is used for a tread, for example, it is extruded on a tread member, and is pasted and molded by a usual method on a tire molding machine to form a raw tire. The green tire is heated and pressed in a vulcanizer to obtain a tire.

The present invention will be described below based on examples, but the configuration of the present invention is not limited to the following examples.
<Production example of hydrolyzed natural rubber>
(Production example a)
(1) Enzymatic treatment process of natural rubber latex Water added to natural rubber latex (within 1 hour after collection) treated with clone species GT-1 and NH ₃ 0.4 wt% to a solid content concentration of 15 wt% To the prepared latex solution 1000 g, phospholipase (2000 LEN / g Novozyme) was added to each 100 parts by mass of latex solids in a proportion of 5.0 parts by mass, stirred, and dispersed. It was allowed to stand for 16 hours. The latex solution was adjusted to pH 8 and reacted at room temperature (25 ° C.).
(2) Coagulation / Drying Step Next, formic acid was added to the obtained latex to adjust the pH to 4.7 and coagulate. This solid was crushed 5 times with a scraper through a shredder, and then dried with a hot air dryer at 110 ° C. for 210 minutes to obtain natural rubber.
The degradation rate of phospholipid was 87%, and the amount of undegraded phospholipid of natural rubber was 0.12 wt%.

<Production example of high hydrogen carbon black>
(Production Example 1: Production of carbon black A)
Carbon black A was manufactured using the carbon black manufacturing furnace shown in FIG. However, in FIG. 4, as the multistage rapid refrigerant introduction means 12, a three-stage configuration comprising a first rapid refrigerant introduction means 12-X, a second rapid refrigerant introduction means 12-Y, and a final rapid refrigerant introduction means 12-Z. The rapid refrigerant introduction means was used.
Moreover, in order to monitor the temperature in a manufacturing furnace, the said manufacturing furnace provided with the structure where a thermocouple can be inserted in a furnace in arbitrary several places was used. In the carbon black production furnace, A heavy oil having a specific gravity of 0.8622 (15 ° C./4° C.) was used as the fuel, and heavy oil having the properties shown in Table 1 below was used as the feed oil. The operating conditions of the carbon black production furnace and the characteristics of carbon black are shown in Table 2 below.

(Examples 1-4 and Comparative Examples 1-4)
Extracted from each production example, in Examples 1 to 4, using the production example a of natural rubber phospholipid enzymatic decomposition, using a production example A and B of high hydrogen carbon, Banbury mixer, the following Table 3 Eight types of rubber compositions were prepared according to the formulation of the rubber composition shown below. In Comparative Examples 1 to 4, natural rubber is usually used (the amount of enzyme added in Production Example a is 0, the degradation rate of phospholipid is 0%, and the amount of undegraded phospholipid of natural rubber is 0.91 wt%). The rubber composition was adjusted.

Next, eight types of truck tires having a tire size of 11R22.5 using these eight types of rubber compositions as treads were produced, and rolling resistance and wear resistance were evaluated. These results are shown in Table 4 below.
The tire wear resistance and rolling resistance were evaluated according to the following methods.
(1) Wear resistance evaluation method The test tire is mounted on a vehicle, the remaining amount of the groove is measured when the vehicle runs 40,000 km, and the index is displayed with the reciprocal of the remaining amount of the tire of Comparative Example 1 being 100. did. The larger this value, the better the wear resistance.
Wear resistance index = (remaining groove of the test tire) × 100) / (remaining groove of the tire of Comparative Example 1)
(2) Evaluation method of rolling resistance The running resistance when the drum was rotated freely on the drum was measured. Based on the rolling resistance value thus obtained, a rolling resistance index was determined according to the following formula. The higher the value, the better the rolling resistance.
Rolling resistance index = (Rolling resistance value of test tire × 100) / (Rolling resistance value of tire of Comparative Example 1)

  As is clear from the results of Table 4 above, Examples 1-4, which are the scope of the present invention, have characteristics such as wear resistance and reduced rolling resistance, compared to Comparative Examples 1-4, which are outside the scope of the present invention. It was found to be excellent.

  The rubber composition and tire according to the present invention are a combination of natural rubber and reactive high hydrogen carbon black, which exhibits reactivity and improved oxidative aging characteristics, thereby reducing wear resistance and rolling resistance. It has excellent characteristics and has high industrial applicability.

Claims (7)

Using a reaction apparatus in which a natural rubber obtained by hydrolyzing phospholipids of natural rubber molecules, a combustion gas generation zone, a reaction zone, and a reaction stop zone are connected in series, a high-temperature combustion gas is generated in the combustion gas generation zone. And then forming a reaction gas stream containing carbon black by spraying the raw material into the reaction zone, and then quenching the reaction gas stream by the multistage rapid refrigerant introduction means in the reaction stop zone. High hydrogen carbon black obtained by terminating
Further, high hydrogen carbon black is used in the multistage rapid refrigerant introduction means in the following relational expressions (1) and (2).
10 <X <40 (1)
90 <Z <100 (2)
(However, X represents the toluene coloring permeability (%) of carbon black after introduction of the first quenching medium from the raw material introduction position, and Z represents the toluene coloring permeability of carbon black after the last quenching medium introduction ( %)).) A rubber composition characterized by satisfying The residence time in the zone from when the raw material is sprayed into the reaction zone until the first quenching medium is introduced is t ₁ (seconds), the average reaction temperature in this zone is T ₁ (° C.), The residence time in the zone from the introduction of the first quenching medium to the introduction of the quenching medium by the second quenching medium introduction means is t ₂ (seconds), and the average reaction temperature in this zone is T _2. (° C.), and the residence time in the zone from the introduction of the second quenching medium to the introduction of the last quenching medium is t ₃ (seconds), and the average reaction temperature in this zone is T ₃ (° C.), the following relational expressions (3), (4) and (5)
2.00 ≦ α1 ≦ 5.00 (3)
5.00 ≦ α2 ≦ 9.00 (4)
−2.5 × (α1 + α2) + 85.0 ≦ β ≦ 90.0 (5)
(However, α1 = t ₁ × T ₁ , α2 = t ₂ × T ₂ , β = t ₃ × T _4. )
The rubber composition according to claim 1, wherein the rubber composition is controlled so as to satisfy a high hydrogen carbon black.   The rubber composition according to claim 1 or 2, wherein 50% or more of the phospholipid in the natural rubber is decomposed. The rubber composition according to any one of claims 1 to 3, wherein undegraded phospholipid in the natural rubber is 0.66% by weight or less.
(The undegraded lipid is weight% representing the amount g of fatty acid contained in 100 g of rubber.)   The rubber composition according to any one of claims 1 to 4, wherein the hydrolysis of the phospholipid is an enzyme treatment.   The rubber composition according to any one of claims 1 to 5, comprising 10% by mass or more of natural rubber based on the total amount of the rubber component.   A tire using the rubber composition according to any one of claims 1 to 6.

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