JPH01297438A - Rubber composition for tire - Google Patents

Abstract

PURPOSE:To provide the subject composition having good processability and excellent strength and wear resistance by compounding a specific carbon black and a vulcanizing agent with raw material rubber components comprising a specified polybutadienic composite polymer and a natural rubber polymer. CONSTITUTION:35-80 pts.wt. of reinforcing carbon black having an iodine adsorbing amount of 90-140mg/g and a DBP oil-absorbing amount of 110-140ml/100g and 0.5-3 pts.wt. of a vulcanizing agent are compounded with 100 pts.wt. of raw material rubber components comprising (A) 10-70wt.% of a composite polymer having a trans bond amount (bond amount) of 55-80% and a Mooney viscosity of 25-150 and comprising (i) a block copolymer comprising resinous trans-polybutadiene blocks having a crystal melting point of 30-130 deg.C, a bond amount of >=80% and a weight-average mol.wt. of 20,000-200,000 and rubbery polybutadiene blocks having a glass transition point of <=-70 deg.C, a bond amount of 40-60% and a weight-average mol.wt. of 40,000-400,000 and (ii) a rubbery polybutadiene having the same physical properties as the above-mentioned rubbery blocks and (B) 20-90wt.% of natural rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a rubber composition for tires having excellent processing performance and improved physical properties. More specifically, the present invention uses an improved butadiene-based composite polymer and a natural rubber-based polymer as raw material rubber, as well as a tire that uses a specific carbon black and has good processability and excellent strength and wear resistance. This relates to rubber compositions for use in rubber compositions. This rubber composition is a composition suitable for use in various tires including tread compositions for large tires such as trucks and buses.

[Prior Art] Conventionally, rubber compositions for automobile tire treads have been made of natural rubber, styrene-butadiene copolymer rubber, polybutadiene, and other synthetic rubbers, either singly or appropriately blended, depending on the intended use of the tire. It is used as.

Recently, the transportation of goods by automobiles has become popular, and large trucks are increasingly used to transport goods in large quantities, at high speeds, and over long distances. In addition to properties such as heat resistance and heat resistance, good abrasion resistance is now required.

In contrast, conventionally, for the treads of large tires, natural rubber or a blend of natural rubber and polybutadiene rubber has been used as the rubber, and carbon black, which has high reinforcing properties, has been used to improve wear resistance. was common.

However, when natural rubber is used alone, strength and heat resistance are good, but there are problems with abrasion resistance.On the other hand, when natural rubber and polybutadiene rubber are used, especially high-cis polybutadiene rubber as polybutadiene rubber, Although there was some improvement in abrasion resistance, there were problems with cut resistance and chipping resistance.

In order to improve both the abrasion resistance and chip cut resistance of rubber compositions for treads of large tires, JP-A-61-143453 discloses that the amount of trans-1,4 bonds is increased as raw material rubber. Rubber compositions using 70% or more of polybutadiene rubber, natural rubber, and other rubbers and further using specific carbon black have been proposed. but,
Polybutadiene rubber with a high trans-1,4 bond does not have sufficient processability in the molding process due to crosstalk even when blended with natural rubber, which has good processability. There were problems such as the quality became inferior.

In addition, as a method for improving high trans polybutadiene, Japanese Patent Application Laid-Open No. 61-238845 discloses a high trans polybutadiene.
A block copolymer consisting of BR and high vinyl SBR has been proposed, and a vulcanized rubber composition containing this block copolymer has also been proposed, but high trans SBR has a high glass transition temperature due to the copolymerization of styrene. Moreover, the crystal melting point was low, such as below room temperature, or did not exist, and the effects of improving wear resistance and strength that the high trans portion had were insufficiently expressed.

[Problems to be solved by the invention] The present invention solves problems that could not be solved by the conventional methods described above.
The aim is to provide a rubber composition for tires that maintains the basic performance of tires such as heat resistance and braking properties, has improved wear resistance and cut resistance, and also has good moldability. It is.

[Means for Solving the Problems] In order to solve the above problems, the present inventors conducted intensive studies on polymers used in rubber compositions, and found that by using a composite polymer consisting of a polymer with a specific structure, The inventors discovered that the object could be achieved and completed the present invention.

That is, the present invention provides a rubber composition for tires having the following components (I>, (n), and (III)).

<I> Component: Consists of the following (A) component, (B) component and (C) component,
Raw rubber components whose total amount is 100 parts by weight.

Component (A): Block copolymer having a resinous trans polybutadiene block and a rubbery polybutadiene block (A-1
), and a polybutadiene-based composite polymer mainly composed of rubber-like polybutadiene (A-2), which is a block copolymer (A-2).
1) The crystalline melting point of the resinous transpolybutadiene in
0 to 130℃ trans bond amount is 80% or more, weight average molecular weight is 20,000 to 200,000, glass transition temperature of rubber-like polybutadiene block is 170℃ or less, trans bond amount is 40 to 60%, weight The average molecular weight is 40,000 to 400,000, the glass transition temperature of the rubbery polybutadiene (A-2) is 170°C or less, the trans bond amount is 40 to 60%, and the weight average molecular weight is 40,000 to 400,000, The amount of trans bonds in the entire composite polymer is 55 to 80%, and the Mooney viscosity (ML
, 100°C) of 25 to 150 and 1+4.

Component (B): 20 to 90% by weight of natural rubber or polyisoprene rubber having a cis bond content of 90% or more.

(C) Component Polybutadiene rubber or styrene-butadiene copolymer rubber O-3 having a glass transition temperature of -110 to -30°C
0 weight 1%.

Component (II): Reinforcing carbon black with an iodine adsorption amount of 90 to 140 ffig/g and a DBP oil absorption amount of io to 140 d/100 g (I>35 to 8 d/g for 100 parts by weight of component)
0 parts by weight.

Component (m): 0.5 to 3.0 vulcanizing agent per 100 parts by weight of component (I)
Heavy interspace.

The present invention will be explained in detail below.

The raw rubber components of the rubber composition of the present invention are (A>component: 10 to 10% by weight of polybutadiene composite polymer, (B)
Ingredients: Natural rubber or polyisoprene rubber with a cis bond content of 90% or more, 20 to 90% by weight, component (C) polybutadiene rubber or styrene-butadiene copolymer rubber with a Nigaras transition temperature of -110 to -30°C. 0
~30% by weight.

Next, the polybutadiene composite polymer of component (A) will be explained.

The polybutadiene-based composite polymer of the present invention is mainly composed of a block copolymer (A-1) having a resinous transpolybutadiene block and a rubbery polybutadiene block, and a rubbery polybutadiene (A-2).

The block copolymer (A-1) consists of a resinous transpolybutadiene block and a rubbery polybutadiene block, and the resinous transpolybutadiene block has a crystal melting point of 30 to 130°C, a trans bond content of 80% or more,
The weight average molecular weight ranges from 20,000 to 200,000, while the rubbery polybutadiene block has a glass transition temperature of 170°C.
Below, the trans bond amount is in the range of 40 to 60%, and the weight average molecular weight is in the range of 40,000 to 400,000.

In addition, rubbery polybutadiene (A
-2) has a glass transition temperature of 170°C or less, a trans bond content of 40 to 60%, and a weight average molecular weight of 40,000 to 400,000, and is the same as the rubbery polybutadiene block in the block copolymer. It may be a polymer or may have a different polymer structure.

If the crystalline melting point of the resinous transpolybutadiene block in the block copolymer is lower than 30°C, the strength, abrasion resistance, and cut resistance of the resulting composition will be poor; on the other hand, if the crystalline melting point exceeds 130°C, the resinous The trans-polybutadiene block is difficult to crosslink sufficiently, resulting in decreased strength and poor heat resistance.

In the present invention, the crystalline melting point of the resinous transpolybutadiene block is preferably in the range of 40 to 120°C, more preferably in the range of 50 to 110°C.

If the amount of trans bonds in the resinous trans polybutadiene block in the block copolymer is lower than 80%, wear resistance, strength, and hardness will decrease, which is undesirable.

It is more preferable that the amount of trans bonds in the resinous trans polybutadiene moiety is 82 to 95%.

If the weight average molecular weight of the resinous transpolybutadiene block in the block copolymer is lower than 20,000, the strength, abrasion resistance, heat resistance, and anti-bacterial properties will be poor; on the other hand, if the weight average molecular weight exceeds 200,000, This is not preferable because the composite polymer becomes hard, the processability of kneading, molding, etc. deteriorates, and it becomes difficult for the composite polymer to exhibit its original performance. The weight average molecular weight of the resinous transpolybutadiene portion is 40,000 to 20
More preferably, it is 10,000.

The molecular weight distribution of the resinous transpolybutadiene block of the block copolymer (the ratio of the mold mouth average molecule n (Mw) to the number average molecule ffl (Mn) (Mw /Mn)) is from 1.2 to
The range of 4 is preferable, and the range of 1.2 to 3 is more preferable.

Next, a block copolymer (A-
1) The rubbery polybutadiene block and rubbery polybutadiene (A-2) have a glass transition temperature of 170°C.
If the glass transition temperature exceeds 170°C, the wear resistance will decrease. The polybutadiene rubber having a glass transition temperature of 170° C. or less is a Li-based polybutadiene rubber having a vinyl bond of about 35% or less. Glass transition temperature is -100
-80 degreeC is more preferable.

The rubbery polybutadiene block of the block copolymer and the trans bond content of the rubbery polybutadiene are 40 to 60.
If the amount of trans bonds is less than 40%, the strength and abrasion resistance will be poor, while if the amount of trans bonds exceeds 60%, the static and dynamic rubber-like properties of the composite polymer will be lost. The trans bond amount is more preferably 45 to 55%.

The weight average molecular weight of the rubbery polybutadiene block and rubbery polybutadiene of the block copolymer is 40,000 to 40.
If the weight average molecular weight is lower than 40,000, physical properties such as heat resistance, anti-friction elasticity, abrasion resistance, and strength will be poor.
On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity of the compound increases, causing problems in roll processability and extrusion processability.
It becomes difficult to exhibit good dynamic performance characteristics. The weight average molecular weight is more preferably in the range of 50,000 to 300,000. The molecular weight distribution (Mw/Mn) of the rubbery polybutadiene block and rubbery polybutadiene is preferably in the range of 1.2 to 3.0.

The rubbery polybutadiene block in the block copolymer (A-1) and the rubbery polybutadiene (A-2) may have the same structure or may have different structures within the above range.

In the present invention, the homopolymer of resinous transpolybutadiene is not included in the composite polymer, or the homopolymer of resinous transpolybutadiene has a crystal melting point of 30 to 130°C, a trans bond amount of 80% or more, and a weight of The average molecular weight is 20,000 to 200,000, and the amount is 30% by weight based on the total amount of the resinous trans-polybutadiene block in the block polymer (A-1) and the amount of this resinous trans-polybutadiene homopolymer. % or less.

Resinous trans polybutadiene portion (total amount of both resinous trans polybutadiene blocks and resinous trans polybutadiene homopolymer in the block copolymer)
is preferably contained in a large amount in the block copolymer (A-1) from the viewpoint of wear resistance and heat resistance of the composition, and the amount as the resinous transpolybutadiene homopolymer is the amount of the resinous transpolybutadiene portion. More preferably, it is 20% or less.

Further, the amount of the resinous transpolybutadiene portion is 3 to 70% by weight of the amount of the composite polymer. If the base content of the resinous transpolybutadiene portion is less than 3%, there will be little improvement in processability, strength, and wear resistance, and if these two exceed 70%, the rebound resilience and heat resistance will deteriorate. The amount of resinous transpolybutadiene moiety is 5 to 6 times the amount of composite polymer.
Preferably it is 0% by weight.

In the present invention, the amount of the block copolymer (A-1) forming the composite polymer is at least 5% of the amount of the composite polymer.
Preferably, it is % by weight.

If this amount is less than 5%, the balance between workability and wear resistance will deteriorate, which is not preferable. More preferably, the amount of block copolymer is at least 10% of the amount of composite polymer.

In the present invention, the content of the homopolymer rubbery polybutadiene forming the composite polymer is preferably in the range of 0 to 90% by weight, and more preferably in the range of 0 to 80%.

The amount of trans bonds in the entire composite polymer of the present invention is 55 to 8
The range is 0%. If the amount of transformer bonding ports is less than 55%, the strength and wear resistance of the composition will not be sufficient, and if the amount of transformer bonding exceeds 80%, the heat resistance and low temperature characteristics of the composition will deteriorate. This trans bond amount is 60 to 75
% range is particularly preferred.

Furthermore, the Mooney viscosity (ML
, 100°C) is in the range of 25-150.

1+4 If the Mooney viscosity is lower than 25, the heat resistance, abrasion resistance, and strength of the composition will be poor, and if the Mooney viscosity exceeds 150, the roll processability and extrusion processability of the composition will deteriorate. When the Mooney viscosity of the composite polymerizable product is 70 or more, it is possible to adjust the Mooney viscosity to a range that is easy to process by adding 5 to 50 parts of rubber extender oil per 100 parts of the composite polymer.

The weight average molecular weight of the composite polymer of the present invention is preferably in the range of 40,000 to 400,000.

The molecular weight distribution (Mv/Mn) of the composite polymer of the present invention is 1
．． 2 to 5 are preferable, and 1.2 to 3 are more preferable.

The polybutadiene-based composite polymer of the present invention can be produced by (a) preparing a monomer solution consisting of a butadiene monomer and an inert solvent, and (b) using a catalyst consisting of a rare earth element compound and an organomagnesium compound. Butadiene at a temperature of 80 °C
% or more of trans bonds, (e) Subsequently, an organolithium compound is further added to the above catalyst, and 30 to 2
Produced by a production method whose basic steps are: polymerizing butadiene to 60% or less trans bonds at a temperature of 00°C; (d) removing the inert solvent from the resulting composite polymer. .

The manufacturing method may be a batch polymerization method or a continuous polymerization method.

Step (a) is a step of preparing a monomer solvent consisting of a butadiene monomer and an inert solvent. The inert solvent used in this step is not particularly limited as long as it does not deactivate the catalyst used, but the solvents used include aliphatic or fatty acids such as n-pentane, n-hexane, n-hebutane, and cyclohexane. Cyclic hydrocarbons, benzene,
Aromatic hydrocarbons such as toluene are preferred, and these may be a mixture of two or more or may contain a small amount of impurities. Butadiene is formulated in a solvent at a concentration of 1 to 50%, preferably 5 to 30%. Butadiene may also contain a small amount of allenes such as propadiene and 1,2-butadiene.

Step (b) is a step in which butadiene is polymerized into trans bonds by 80% or more at a temperature of 0 to 150° C. using a catalyst comprising a rare earth element compound and an organomagnesium compound. The rare earth element compounds used in this process, which are the main components of the catalyst, include lanthanum, cerium,
Element number 57 such as praseodymium, neodymium, samarium, etc.
It is a compound containing ~71 elements, and preferable elements include lanthanum, cerium, and neodymium, and organic acid salts thereof are used as suitable compounds. Examples of organic acids include alcohols, thioalcohols, phenols, thiophenols, carboxylic acids, thiocarboxylic acids, alkylarylsulfonic acids, monoalcohol esters of sulfuric acid, phosphoric acid compounds, and the like. Another catalyst component in step (b) is an organomagnesium compound, examples of which include:
Diethylmagnesium, di-n-propylmagnesium, diisopropylmagnesium, di-n-butylmagnesium and the like are preferred. These two component catalysts have a rare earth compound/organomagnesium compound ratio of 11
It is used in the range of 0.1 to 1150.

Furthermore, in this step, in order to enhance the activity of the organomagnesium compound, it is also possible to coexist an organolithium compound or an organoaluminum compound. Preferred examples of organolithium compounds include n-propyllithium, isopropyllithium, n-butyllithium, 5ec-butyllithium, and tert-butyllithium. It is possible to change the amount of trans binding in the polybutadiene obtained. Preferred examples of the organoaluminum compound include [-limethylaluminum, triethylaluminum, triisopropylaluminium, 1-lysobutylaluminium, and diethylaluminium hydride.

In this step, the polymerization reaction uses the above catalyst system,
The polymerization is carried out at a temperature of 0 to 150°C, preferably 30 to 120°C, and the polymerization format may be a batch method or a continuous method. In this step, the polymerization is allowed to proceed so that the proportion of the obtained high trans polymer in the reactivated polymer is 3 to 70% by weight, preferably 5 to 60% by weight, and the following (C) Subsequently, an organolithium compound is further added to the above catalyst, and the process proceeds to a step of polymerizing butadiene to 60% or less trans bonds at a temperature of 30 to 200°C.

The organic lithium compound used in this step is n
- Propyllithium, isopropyllithium, n-butyllithium, 5ee-butyllithium, tert-butyllithium, etc. are preferred, and the amount of these organolithium compounds to be used is determined between the lithium atom in the organolithium compound and the amount in the organomagnesium compound. Li/Mg molar ratio is 2.
0 or more, preferably 2.5 or more, especially when the trans bond amount of the polybutadiene polymerized in this step is 55
% or less, it is 3.0 or more, preferably 4.0 to 5.0 or more.

Further, like the organolithium compound added in this step, a Lewis base can be used in the catalyst for the purpose of increasing the polymerization activity or increasing the amount of 1,2-vinyl bonds and lowering the amount of trans bonds. Suitable Lewis bases include ethers, thioethers, tertiary amines, etc. Examples of these include dimethyl ether,
Ethers such as diethyl ether, tetrahydrofuran, anisole, monoglyme, diglyme, triethylamine, tripropylamine, N, N, N', N'-
These are tertiary amines such as tetramethylethylenediamine and dipiperidinoethane, and thioethers such as thiophene and thiotetrahydrofuran. The preferred amount of these Lewis bases used is 0.0 per mole of organolithium compound.
It is about 1 to 50 moles.

Polymerization is carried out at a temperature of 30 to 200°C, preferably 50 to 150°C, using a catalyst additionally added with the above-mentioned organolithium compound. In this step, the monomer mixture prepared in step (a) or the monomer mixture prepared in another composition may be introduced into the polymerization system. In this case, both the residual monomer that was unreacted in the step (b) and the monomer introduced in the step (C) are polymerized in the step (C). Step (C) is a step of polymerizing butadiene into a substance having a trans bond of 60% or less, preferably 55% or less, and the portion having a relatively low amount of trans bonds polymerized in the step (C) The proportion in composite polymer is 30-97%
Polymerization is allowed to proceed as follows. After the polymerization reaction reaches a predetermined reaction rate, a known polymerization terminator is added to the reaction system to stop the polymerization reaction. Next, in step (d), the polymerized composite polymer and the solvent are separated by a solvent removal and drying method used in the production of ordinary rubbery polymers.

In the above manufacturing method, the molecular weight, number of molecules, microstructure, etc. of each component constituting the composite polymer are (b) and (C).
It is possible to control the control depending on the composition of the catalyst used in the process, the stirring specific polymerization wetness, the amount of monomers, etc.

In addition, in the step (C), utilizing the reactivity of the activated lithium-terminal end of the produced polymer, a known coupling reaction technique or terminal modification technique is applied to impart a branched structure (6), It is also possible to expand the molecular M distribution and improve the interaction between the polymer and the additive.In these coupling reaction techniques, polyfunctional compounds with more than two functionalities are used. as dibutyltin dichloride,
DiA-ctyl tin dichloride, medyl benzoate, butyl tin trichloride, butyl silicon trichloride, tin tetrachloride, silicon tetrachloride, diethyl adipate, dimethyl carbonate, epoxidized soybean oil, liquid epoxidized polybutadiene, ethylene bistrichlor Examples include silane, tetraglycidyldiaminomedylcyclohexane, and tetraglycidyldiaminodiphenylmethane.

Through the coupling reaction, the resulting composite polymer has improved cold flow, green strength, processability, and the like.

In addition, terminal modification techniques include the reaction of active lithium terminals with trialkyl tin chloride or triallyl tin chloride, and compounds I having a 10-N< bond in the molecule (where X represents an oxygen or sulfur atom). ), N, N-
Examples include reactions with active compounds such as dialkylamino aromatic aldehyde compounds, N,N-dialkylamino aromatic ketone compounds, isocyanate compounds, thioisocyanate compounds, and carbodiimide compounds; introduction of these reactive groups When the resulting composite polymer is made into a vulcanized rubber composition, it has improved dynamic performance such as rebound elasticity and heat resistance.

The amount of the composite polymer which is component <A> of the raw material rubber described above is 10 to 70% by weight of the raw material rubber.

If the amount of component (A) is less than 10%, the effect of improving the wear resistance and processability of the vulcanized composition will not be sufficient, and
If it exceeds %, heat resistance and low temperature performance will be poor.

The amount of component (A) is preferably in the range of 20 to 60% by weight of the raw rubber.

Next, component (B) of the raw rubber component is natural rubber or polyisoprene rubber having a cis bond content of 90% or more.

This raw rubber component, together with component (A), is a main component of the tire rubber composition according to the present invention, and is an essential component for making the rubber composition excellent in strength, durability, and heat resistance.

Crumb rubber, which is produced in various countries around the world, is a natural rubber.
Sheet rubber is used. Polyisoprene rubber having a cis content of 90% or more is a synthetic rubber polymerized using a Zeigler-Natta catalyst or a l-i catalyst. The rubber base of these component (B) is 20 to 9 of the raw rubber.
It is 0 weight and 1%. If component (B) is less than 20% by weight, strength, chip cut resistance, and heat resistance are insufficient, and if it exceeds 90% by weight, wear resistance is poor. It is more preferable that the component (B) is 30 to 80% of the weight of the raw rubber.

Furthermore, as the raw material rubber component, as component (C), 0 to 3% of polybutadiene rubber or styrene-butadiene copolymer rubber having a glass transition temperature of -110 to -30'C is used.
It can be used in a range of 0% by weight. Component (C) is used to give the rubber composition performance that is not necessarily sufficient when the rubber composition uses only the above-mentioned (A) and (B) components as raw rubber, such as wet skid resistance. be done. Rubbers used as component (C) include high cis polybutadiene rubber, low cis polybutadiene rubber, high vinyl polybutadiene rubber, emulsion polymerized styrene-butadiene copolymer rubber, and solution polymerized low vinyl styrene-butadiene copolymer rubber. , solution-polymerized vinyl styrene-butadiene copolymer rubber, solution-polymerized high vinyl styrene-butadiene copolymer rubber, etc. may be used within the range that does not impair the desired characteristics of the rubber composition of the present invention.

Next, in the rubber composition of the present invention, carbon black has an iodine adsorption amount of 90 to 140 mg/'i,
A proportion of 35 to 80 parts by weight of DBP having an oil absorption of 110 to 140rd/100g is blended to 100 parts by weight of raw rubber.

Iodine adsorption amount of carbon black is 90mFi/';J
If it is not swirled, it will not have sufficient strength and wear resistance, and 140In
When FI/'j is exceeded, heat resistance and anti-slip elasticity deteriorate. In addition, if the DBP oil absorption amount is less than 110 m1/100 g, the wear resistance and cut resistance will be poor;
If it exceeds g, the modulus becomes too high and workability deteriorates, which is not preferable. The iodine adsorption amount of carbon black is preferably in the range of 100 to 135/Ffff/g, and the DBP oil absorption amount is more preferably in the range of iio to 130 d/100 g.

If the amount of carbon black is less than 35 parts by weight per 10 parts by weight of raw rubber, strength, abrasion resistance, and cut resistance will be poor, and if it exceeds 80 parts by weight, heat resistance and chipping resistance will be reduced. Raw rubber 100 between carbon black
More preferably 400 to 75 parts per 1,000 parts.

Next, in the rubber composition of the present invention, 0.0% of the vulcanizing agent is added.
Mix 5 to 3.0 parts.

Sulfur is a typical vulcanizing agent and is preferably used, and other vulcanizing agents include sulfur-containing compounds such as tetramethylthiuram, disulfide, morpholine, and disulfide.
Oximes and peroxides are used.

Furthermore, in the rubber composition of the present invention, a rubber extender oil and a rubber chemical are blended as necessary. Extending oil for rubber is
It is used to improve the processability of compounds and to adjust the hardness of compounds, and aromatic, naphthenic, and paraffinic types are typical.
0 to 30 parts by weight per i part. Rubber chemicals include vulcanization accelerators such as zinc white and stearic acid, vulcanization accelerators such as sulfenamides, thiurams, thiazoles, and guanidines, anti-aging agents such as amines, phenols, etc. Antioxidants, ultraviolet absorbers, tackifiers, plasticizers, inorganic fillers, etc. are blended depending on the intended use.

The rubber composition of the present invention is produced by mixing and kneading the above-mentioned components using a rubber mixing device such as a rubber kneading roll, an internal mill, or an extruder, and then molding and assembling it into a tire using a conventional method. It is vulcanized under pressure at a temperature of ~200°C and ready for use.

The composition of the present invention obtained as described above exhibits the following characteristics compared to existing vulcanized rubber compositions in which carbon black is blended with natural rubber/synthetic rubber.

It has better tensile strength, abrasion resistance, and processability than a composition using ordinary polybutadiene rubber (high-cis polybutadiene or low-cis polybutadiene) as a synthetic rubber.

Moreover, the processability is better, and the strength and cut resistance are also better than a composition using polybutadiene having a 1-lance bond content of 70% or more as a synthetic rubber.

Furthermore, compared to compositions using styrene-butadiene copolymer as the synthetic rubber, the composition has better abrasion resistance, rebound resilience, and heat resistance.

[Example] Hereinafter, the characteristics of the composition of the present invention will be explained in more detail with reference to Examples.

(2) Preparation of the polymer of the present invention used in the Examples A composite polymer (sample A) used in the rubber composition for tires of the present invention was obtained by the following method.

Two stainless steel reactors with an internal volume of 10 g and a height-to-inner diameter ratio (L/D) of 4 and a jacket are connected in series, and from the bottom of the first reactor 1, 3 A solution of -butadiene in n-hekyrin and lanthanum versatate, dibutylmagnesium, and n-butyllithium as catalysts were continuously supplied, and the internal temperature of the reactor was maintained at 77°C to carry out the polymerization reaction. The solution concentration of butadiene was 18%, and the feed rate of butadiene was 0.67 K.
It was set as l/hr. The amount of catalyst supplied is 100g of butadiene.
0.15 mmol of lanthanum versatate per
, dibdelmagnesium was set to 0.80 mm0I, and n-butyllithium was set to o, 10 mm0+.

Once the polymerization reaction in the first reactor had reached a steady state and was stable, the polymer solution was poured from the head outlet of the first reactor, and the union rate was measured and found to be 69.4%. The microstructure of the obtained polymer was 87% trans bonds, 7% cis bonds, and 6% vinyl bonds, and the glass transition temperature measured by DSC was -86°C1.The crystalline melting point was -8.
Molecular weight by GPC at 5°C: MW = 117,000, M
n = 51,000, MW /Mn = 2.3, and the shape of the curve was one gentle peak.

The polymer solution from the first reactor is introduced into the bottom of the second reactor, and additional n-1,3-butadiene is added from the bottom of the second reactor.
Hekylin solution and n-butyllithium were fed continuously. The concentration of the butadiene solution introduced into the second reactor was 18% by weight, and the feed rate of butadiene was 0.67 Ny/
It was set as hr. The amount of n-butylriboum introduced into the second reactor was 1.60 mmol per 100 g of butadiene supplied to the second reactor. After polymerization was carried out while maintaining the internal temperature of the second reactor at 120'C, 2,4-jet was added as a stabilizer to the polymer solution coming out from the head of the second reactor.
ert-butyl-p-cresol is continuously fed and mixed at 0.6 parts per 100 parts of polymer, and the polymer solution is then introduced into hot water and steam stripped to remove the solvent. Removed. The obtained rubbery polymer was dried with a hot roll to obtain the desired composite polymer sample A).

The reaction rate at the outlet of the second reactor was 99.8% based on the total feed. The microstructure of the obtained polymer was 64% trans bonds, 26% cis bonds, and 10% vinyl bonds, and the Mooney viscosity (ML,
100'C) is 52, MW by GPC = 1 + 4 202,000, Mn-7o, 0,000, Mw /Mn = 2
．． 02, and the shape of the GPC curve was a gentle curve.

From the above analysis results, the resinous trans polybutadiene portion polymerized in the first reactor with a trans bond content of 87% is 35% by weight based on the total gold polymer, and the low trans polybutadiene portion polymerized in the second reactor is The rubbery polybutadiene portion is 65% by weight of the composite monomer body, and its microstructure is reduced to 52% trans bonds, 35% cis bonds, and 13% vinyl bonds.

After heating and dissolving 2 g of the obtained composite polymer in 100M1 of a mixed solvent of n-hexane and cyclohexane, this was OoC.
The mixture was cooled to 0.degree. C. and centrifuged while being maintained at 0.degree. C. to separate the precipitate and the solution. When the obtained precipitate was dried and weighed, it was found to be 0.8i1% based on the composite polymer. However, high trans resinous polybutadiene homopolymer is
The amount was 2.3% by weight based on the polybutadiene obtained in the first group (total amount of high trans resinous polybutadiene and resinous trans polybutadiene homopolymer in the block polymer). Table 1 shows the analytical values of the composite polymer (sample A).

Polymerization conditions such as the amount of catalyst, the composition ratio of each component of the catalyst, the ratio of supply to the first reactor and the second reactor of the seven-unit reactor, and the polymerization temperature were determined in the same manner as for obtaining sample A. Samples B to N having the analytical values shown in Table 1 were obtained by varying the values. Sample N is 1
It is a polymer only for the base reactor. Note that Sample G was prepared not by the continuous polymerization method but by the batch polymerization method. Therefore, the analytical values in Table 1 for the polymer discharged from the first reactor are the analytical values for the polymer lean-pulled immediately before adding additional butadiene and )-butyllithium during the reaction.

Furthermore, rubbery transpolybutadiene (Sample P) prepared using the barium-magnesium catalyst shown in Table 2
and a commercially available rubbery polymer (sample Q-T) were prepared.

Next, the measurement method used in the present invention will be explained.

Analysis of the microstructure of polybutadiene in the present invention is as follows:
The sample was dissolved in carbon disulfide, and the infrared absorption spectrum was measured using an infrared spectrophotometer (JASCO Model A-202), and the amounts of cis, trans, and vinyl bonds were measured using the Morello method.

In the present invention, the molecular weight is measured by GPC (Shimabara Seisakusho, L.
C-5A type, Columnide l5G40.50.60゜1 each
The average molecular weight of polybutadiene was calculated in accordance with a conventional method using a calibration curve previously determined from the relationship between the molecular weight of the peak of standard polystyrene and the number of elution counts.

The glass transition temperature and crystal melting point were measured using a DSCC (Seiko Electronics, DSC-20 model) at a heating rate of 10°C/
Measured at min. The glass transition temperature is the starting point of the DSC curve, and the crystalline melting point is the peak temperature (midpoint).

(Left below) ■Preparation and measurement of rubber composition The rubber composition was prepared according to the evaluation formulation shown in Table 3, with a content of 1
．． 7. ASTM-D-3403-7 using a Q test Panbury millimeter and a 10-inch test roll.
After kneading and molding according to the mixing specifications of Method B of the standard mixing procedure shown in Section 5, the mixture was vulcanized at 145° C. for 35 minutes, and the physical properties were measured. The measurements were carried out according to the following method.

(1) Blend Mooney viscosity=Using an L-type rotor, 1
Measured at 00'C.

(2) Hardness, tensile test, JIS-K-6301
Measured according to.

(3) Anti-l! ii! Elasticity: JIS-K-63
Using the No. 01 impact measuring device, the sample was preheated in an oven at 70°C for 1 hour, then quickly taken out and the impact resilience at 70'C was measured.

(4) Gutsudori heat generation: Using a Gutsudori flexometer, the test was carried out on strip 1 with an applied load of 24 bonds, a displacement of 0, 225 inches, a start of 50'C, and a rotation speed of 180 Orpm, and after 20 minutes. The temperature rise difference was measured.

(5) Wear resistance: Measured using an improved Lambourn abrasion tester under the conditions of a non-pull rotation speed of 50 Trt/min, a slip rate of 24%, and a load of 5 kg. Expressed as an index with the standard formulation using natural rubber set as 100. The higher the number, the better the wear resistance.

(6) Cut resistance Using a DuPont type dart tester, the thickness of 5 was placed horizontally.
A blade with a tip shape of 1 # x 10 m and an angle of 30° is placed on a vulcanized rubber sample of mm in diameter, and a predetermined amount of sag is allowed to fall naturally onto the blade. Cut resistance is determined by the initial height and hanging weight. It is graded from 1 to 5, and the higher the number, the better the cut resistance.

(7) Roll operability: Stuck state of compound stock on 10-inch roll;
Determined by the shape of the edge. The higher the number, the better.

Examples 1-1 to 1-7, Comparative Examples 1-1 to 1-9 Samples A-G, which are composite polymers within the scope of the present invention, and polymers 11 to Q outside the scope of the present invention shown in Table 4 were used. Using the composition with natural rubber as a raw material rubber, compositions having the formulations shown in Table 3 were prepared, and the processability was determined and the vulcanizate properties were measured. The results are shown in Table 4.

As shown in Table 4, Examples 1-1 to 1 consisting of a composite polymer having the structural factors specified in the present invention and natural rubber
Composition -7 has good processability and a good balance of tensile strength, rebound resilience, abrasion resistance, and processing resistance, but the composition consists of a polymer outside the scope of the present invention and natural rubber. The product has poor processability or some of the vulcanizable properties.

(Left below) Raw material rubber for table evaluation N 220 Carbon Black Zinc White No. 1 Stearic acid anti-aging agent 87 ON 8 * 2 Io * 1 Tokai Carbon Co., Ltd., Commercial Ir Iodine absorption 121 mg / DBP oil absorption 11 nop -Phenylenediami*3 N-tert-butyl-1 Benzothiazyl Suno-100 parts*1 50 parts 3 parts 2 parts 2 parts 1, 75 parts 1 part Ciestro'J' 100g 4' -Phenyl-mine? - Lefurenamide Examples 2-1 to 2-5, Comparative Examples 2-1 to 2-5 Using sample A (composite polymer) and natural rubber as raw rubber,
It is shown in Table 5 as carbon black. Rubber compounds having the compositions shown in Table 6 were prepared using rubber compounds having different amounts of iodine adsorption and DBP oil absorption, and the processability and physical properties of the vulcanizates were evaluated. The results are shown in Table 6.

As is clear from the results in Table 6, iodine absorption 1 and DBP
The compositions of Examples 2-1 to 2-5 using carbon black with oil absorption within the range defined by the present invention all have good physical properties of the vulcanizate, but Comparative Examples 2-1 to 2-2 Compositions using carbon black outside the scope of the present invention in No. 3 have poor tensile strength and abrasion resistance even when composite polymers are used as raw rubber.

(Left below) Examples 3-1 to 3-7, Comparative Examples 3-1 to 3-5 Using the evaluation formulations shown in Table 3, compositions using raw rubber having the composition shown in Table 7 were prepared and evaluated. The results are shown in Table 7.

As is clear from the results in Table 7, the compositions of Examples using IJu raw rubber components having compositions within the range defined by the present invention have good vulcanizate physical properties; Compositions of comparative examples that fall outside the range have problems with any of the physical properties of the vulcanizate.

(Left below) Examples 4-1 to 4-4, Comparative Examples 4-1 to 4-4 The evaluation formulations shown in Table 8 and the formulations with the compositions in Table 9 were obtained, and the processability and physical properties of the vulcanizate were evaluated. did. The results are shown in Table 9.

As is clear from the results in Table 9, the vulcanized rubber compositions of Examples have good physical properties of the vulcanizate, whereas Comparative Examples 4-1 to 4-1, in which the amount of carbon black is outside the range of the present invention. The vulcanized rubber composition No. 2 has poor abrasion resistance, tensile strength, processability, and cut resistance.

(Left below) Table 8 Evaluation formulation N 220 carbon black Variable aromatic oil *1 Variable zinc white No. 1
3 parts stearic acid 2 parts anti-aging agent 8
1ONA Part 2
1.75 parts vulcanization accelerator NS 1 part *1: Kyodo Sekisonic It has characteristics such as good abrasion resistance, tensile strength, heat resistance, and crack resistance, and by taking advantage of these characteristics, it is used for light tires such as 1 to 2 tires for large tires such as trucks and buses. It is a vulcanized rubber composition that is suitable for use in 1 - rack treads and construction vehicle 1 - leads, and is also suitably used in parts other than treads of various tires, and is useful in many fields. .

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. A rubber composition for tires having the following components (I), (II) and (III). Component (I): A raw rubber component consisting of the following components (A), (B), and (C) in a total amount of 100 parts by weight. Component (A): Block copolymer having a resinous trans polybutadiene block and a rubbery polybutadiene block (A-1
), and a polybutadiene-based composite polymer mainly composed of rubber-like polybutadiene (A-2), wherein the crystal melting point of the resinous trans polybutadiene in the block copolymer (A-1) is 30 to 130 °C trans bond amount is 80% or more, the weight average molecular weight is 20,000 to 200,000, and the glass transition temperature of the rubbery polybutadiene block is -70%.
℃ or less, the amount of trans bond is 40 to 60%, the weight average molecular weight is 40,000 to 400,000, and rubbery polybutadiene (A-
2) has a glass transition temperature of -70°C or lower, a trans bond content of 40 to 60%, a weight average molecular weight of 40,000 to 400,000, a trans bond content of the entire composite polymer of 55 to 80%, and a Mooney viscosity ( ML_1_+_4, 100℃) is 25-15
10 to 70% by weight of a polybutadiene composite polymer with a
. Component (B): 20 to 90% by weight of natural rubber or polyisoprene rubber having a cis bond content of 90% or more. Component (C): Polybutadiene rubber or styrene-butadiene copolymer rubber 0 to 3 having a glass transition temperature of -110 to -30°C
0% by weight. Component (II): 35 to 80 parts by weight of reinforcing carbon black having an iodine adsorption amount of 90 to 140 mg/g and a DBP oil absorption amount of 110 to 140 ml/100 g per 100 parts by weight of component (I). Component (III): Add 0.5 to 3.0 parts of vulcanizing agent to 100 parts by weight of component (I).
0 parts by weight.