JPS6250349A - Improved conjugated diene rubber composition for tire - Google Patents

Abstract

PURPOSE:To improve vulcanization characteristics and processability, by blending natural rubber or polyisoprene rubber and polybutadiene rubber with an amide compd.-modified conjugated diene polymer and using the resulting mixture. CONSTITUTION:30-90wt% conjugated diene polymer (A) having a Moony viscosity of 30-150 and a glass transition temp. of -100--20 deg.C, obtd. by modifying a conjugated diene polymer contg. active lithium terminals with an amide compd. of the formula (wherein R1 is a 1-6C alkyl, etc.; Y is O, S; n is 3-4), 5-65wt% natural rubber or polyisoprene rubber (B) having a cis-1,4 bonded unit content of 90% or above and 5-65wt% polybutadiene rubber or styrene/ butadiene copolymer rubber (C) having a styrene content of 3-50wt% are mixed in such a proportion that the combined quantity is 100wt% and the rubber component obtd. from components A-C has a weight-average glass transition temp. of -95--40 deg.C. The resulting mixture is used as raw rubber.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a conjugated diene rubber composition for tires with improved physical properties and processability of a vulcanizate. The present invention relates to a conjugated diene rubber composition for tires using three types of rubber as raw material rubber: conjugated diene polymer rubber, natural rubber or polyisoprene rubber, polybutadiene rubber, or styrene-butadiene rubber.

[Conventional technology] Conjugated diene rubbers such as natural rubber, styrene-butadiene copolymer rubber, and polybutadiene rubber have traditionally been used in various parts of automobile tires, such as the tread, carcass, sidewall, and bead area. A vulcanized rubber composition containing rubber compounding agents such as carbon black and rubber extender oil is used as a raw material rubber. The rubber compositions used in each part of these tires are required to have different performance depending on the role of each part. For example, the tread part requires not only physical properties such as wear resistance, braking performance, and heat resistance, but also ease of work and processing such as rollability, extrusion workability, tackiness, and adhesion when manufacturing tires. It is considered important from an industrial perspective, and performance in both physical properties and processability is required. In order to satisfy these demands, raw rubber, carbon black, vulcanizing agents, vulcanization accelerators, and other rubber chemicals used in tire rubber compositions for each purpose are manufactured in various types and amounts according to each purpose. It is used in different formulations. Regarding raw rubber, natural rubber and synthetic rubber such as styrene-butadiene rubber, polybutadiene rubber, butyl rubber, and polychloroprene rubber are used, but in many cases these are difficult to meet the required performance. A blend of two or more types is used.

In particular, in terms of performance, in recent years automobile tires have been required to reduce rolling resistance from the standpoint of energy conservation, and to improve steering stability and braking performance on wet road surfaces from the standpoint of safety. It has become desirable to improve productivity by improving processability.In response to these improvement demands, for example, the rolling resistance and wet skid resistance of polymers for tire treads (
As a method for improving the balance of braking performance (braking performance on wet road surfaces), in JP-A-54-82248, the styrene content is 20 to 40%, the amount of vinyl bonds in the butadiene moiety is relatively large, and the glass transition temperature (Tg) is JP-A-57-73030 discloses a method using a styrene/butadiene copolymer with a styrene content of -50°C or higher.
~30%, the amount of vinyl bonds in the butadiene moiety is 60-85
%, a method using a styrene-butadiene copolymer branched with a specific metal compound, etc. have been proposed. However, in these methods, the polymer used has a relatively high molecular weight or a narrow molecular weight distribution;
The flow properties of the compound are often poor, resulting in poor processability, and to compensate for this, processing oil is added to the lines,
When blended with other rubbers such as natural rubber, the physical properties are significantly reduced, and these polymers have a problem in that it is difficult to maintain the targeted performance characteristics.

Furthermore, as a method for improving processability while improving the balance between rolling resistance and wet skid resistance of polymers for tire treads, JP-A-58-162805
JP-A-59-45338 describes a method using a branched styrene-butadiene copolymer bonded by tin with a wide molecular weight distribution, and JP-A-59-45338 describes a method using a combination of tin and a coupling agent other than tin. A method using a branched styrene-butadiene copolymer obtained by the above method is disclosed.

[Problems to be solved by the invention] However, when using the polymers of these methods,
Although it is possible to improve processability to some extent, there is a problem in that when blended with other polymers, characteristic physical properties deteriorate. The reality is that when attempting to improve a product, it is not possible to fully demonstrate its original performance.

The present invention has been made in view of the above points, and provides a tire that maintains physical properties such as rebound resilience, heat resistance, abrasion resistance, wet skid resistance, and mechanical strength. An object of the present invention is to provide a rubber composition for tires that has improved workability during production.

[Means and effects for solving the problems] The present invention has the following features:
As a result of extensive research into conjugated diene polymers with functional groups bonded to their polymer chains and their compositions, we discovered that they were obtained by the reaction of an active polymer with lithium terminals and a specific amide compound with a cyclic structure. A conjugated diene copolymer, at least one selected from natural rubber or polyisoprene rubber, and further selected from polybutadiene rubber or styrene-butadiene copolymer rubber having a styrene content of 3 to 50% by weight. A vulcanized rubber composition using at least three types of rubbery polymers as raw material rubber has superior impact resilience and heat resistance compared to conventional vulcanized rubber compositions using only raw material rubber, This was made based on the discovery that there is a good balance between these and abrasion resistance and wet skid resistance, and that the unvulcanized compound has excellent addability.

That is, in the present invention, [I] 30 to 80% by weight of the raw material rubber is (a) treated with at least one conjugated diene compound or a conjugated diene compound using an organic lithium compound as a polymerization initiator in an R-hydrogen solvent. A polymer having active lithium terminals obtained by polymerizing a vinyl aromatic compound and a general formula (wherein R1 is an alkyl group, a cycloalkyl group, or an alkoxyalkyl group of 01 to C6, and Y is an oxygen group F or sulfur atom, n represents an integer of 3 to 4) or fC in the above general formula
One unit of the hydrogen atom r- of the polymethylene chain represented by H2fn is obtained by reacting an amide compound substituted with an alkyl group of 01 to C6, and (b) Mooney viscosity (MLI, 4.100°C) is 30～
(C) A conjugated diene polymer having a glass transition temperature (Tg) of -100 to -20°C, [II] 5 to 65% of the raw material rubber contains natural rubber or cis-1,4 bond [III] 5 to 65 weight percent of the raw rubber is polybutadiene rubber or styrene content is 3 to 50 weight percent. [IV] The total volume of the raw material rubbers of [I] to [III] is 100 parts by weight, and [1] to [III] The present invention relates to a conjugated diene rubber composition for tires, characterized in that the raw material rubber has a normal H'F average glass transition temperature of -95 to -40°C.

The rubber composition for tires of the present invention has impact resilience, heat resistance,
A conjugated diene rubber composition for tires with improved processability while maintaining the physical properties necessary for tire rubber compositions such as abrasion resistance, wet skid resistance, and mechanical strength. undertread, carcass,
This rubber composition is suitable for various parts of tires such as sidewalls and bead parts.

The present invention will be explained in detail below.

The modified conjugated diene polymer having a specific functional group used as part of the raw material rubber of the composition of the present invention is a conjugated diene polymer having an active lithium end and a specific hydrocarbon group on the nitrogen atom. A bonded amide represented by the general formula (wherein R1 represents a C! to C6 alkyl group, cycloalkyl group, or alkoxyalkyl group, Y represents an oxygen atom or a sulfur atom, and n represents an integer of 3 to 4) compound or (G in the above general formula)
D3) It is important that the reaction consists of a reaction with an amide compound having a structure in which one or more of the hydrogen atoms of the polymethylene chain represented by n is substituted with an alkyl group of 01 to C6. This has extremely important meaning in achieving the present invention. Normally, in the stoichiometric reaction of a conjugated diene polymer that combines an amide compound with an acyclic structure and a lithium atom, the bond between a carbonyl group and a 7-mino group as described in Japanese Patent Publication No. 42-24174 is cleaved, making it impossible to effectively introduce amine groups into conjugated diene-based polymers, and when this reaction product undergoes hydrolysis, it becomes a secondary amine that deactivates the catalyst.

This reaction is not practical.

On the other hand, in the stoichiometric reaction of the amide compound having a cyclic structure used in the present invention and the conjugated diene polymer that binds lithium atoms in a hydrocarbon solvent, the conjugated diene polymer does not liberate the secondary amine. Functional groups such as amine groups can be reliably introduced into the system polymer. When the conjugated diene polymer thus obtained is blended with compounding agents such as carbon black and process oil, mixed and vulcanized, the vulcanized product exhibits excellent impact resilience and heat resistance.

The conjugated diene polymer having active lithium terminals to be reacted with the above specific amide compound is one type selected from butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, etc. using an organic lithium compound as a polymerization initiator. or more conjugated diene compounds, or the conjugated diene compounds and a vinyl aromatic compound selected from styrene, α-methylstyrene, p-methylstyrene, etc., in a hydrocarbon solvent. After the polymerization reaction is substantially completed, it is subjected to a reaction with the specific amide compound.

Mooney viscosity (ML+
, 4, 100°C) is in the range of 30 to 150, and if the Mooney viscosity is less than 30, the physical properties such as impact resilience and heat resistance of the final vulcanized rubber composition will be poor, while if the Mooney viscosity exceeds 150. This results in extremely high viscosity, poor dispersion of compounding agents such as carbon black, and poor wear resistance.
The target performance cannot be achieved.

In addition, the glass transition temperature (Tg) of the modified conjugated diene polymer
is in the range of -100 to -20°C. The glass transition temperature of a modified conjugated diene polymer is measured by D, S, C, (differential thermal scanning needle), and is determined by the type of conjugated diene compound, vinyl aromatic compound, and bond of the conjugated diene compound as monomers. It can be changed depending on the style and composition.

The above range of glass transition temperature is the range necessary for the obtained rubber composition for tires to maintain impact resilience, heat resistance, abrasion resistant adhesion, tensile strength, and low temperature properties, and the above range Otherwise, a problem will occur with either performance.

When the modified conjugated diene polymer is a copolymer of a conjugated diene compound and a vinyl aromatic compound, the content of the vinyl aromatic compound in the polymer is adjusted to be within the above glass transition temperature range. be done. Examples of base polymers for modified conjugated diene polymers include polybutadiene, polyisoprene, isoprene-butadiene copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, and styrene-isoprene-butadiene copolymer. Preferred are polybutadiene and styrene-butadiene copolymers. In this case, the microstructure of the butadiene moiety is preferably in the range of 10 to 85%, and the styrene content is preferably in the range of 0 to 50% by weight.

The basic performance of the above-mentioned conjugated diene polymer varies greatly depending on the amount of vinyl bonds in the butadiene moiety, the content of styrene, and the chain state of the molecules. Various values can be set depending on the type and amount of other rubbery polymers used. In the case of styrene-butadiene copolymer, analysis (high Proceedings of the Molecular Society of Japan Vol. 29, No. 9, p. 2055) states that in order to improve impact resilience and heat resistance, the single styrene chain should be at least 40% by weight of the styrene content, and the styrene length should be 8 or more styrene chains. Preferably, the chains account for less than 5% by weight of the styrene content. Furthermore, the styrene composition distribution of the copolymer may be uniform or unevenly distributed in the molecular chain, but it is not preferable to form a large amount of blocked styrene.

The modified conjugated diene polymer of the present invention has a molecular weight distribution (Mw/Mn) measured by G, P, and C of 1.2 to 3.
The range of 5 is preferable because it shows a relatively good balance between physical properties and processability.

Regarding the shape of the molecular weight distribution, it may be monomodal or bimodal or more, having a large number of c, p, and c chromatographic peaks.

A polymer having active lithium terminals, which is a precursor of a modified conjugated diene polymer, can be obtained by the method shown below.

A conjugated diene compound is polymerized or conjugated using a lithium-based compound such as n-butyllithium or 5eG-butyllithium as an initiator in an inert hydrocarbon solvent such as n-hexane, cyclohexane, or benzene. Copolymerization of a diene compound and a vinyl aromatic compound produces a polymer with active lithium terminals, but the microstructure of the conjugated diene portion of the resulting polymer, the content and composition distribution of the vinyl aromatic compound, and the Various methods can be employed to achieve a desired polymer structure such as molecular weight distribution. For example, polar compounds such as diethyl ether, tetrahydrofuran, ethylene glycol diethyl ether, etc. By adding ethers and amines such as triethylamine and tetramethylethylenediamine, it is possible to control the microstructure of the conjugated diene moiety of the polymer as well as the composition distribution of the vinyl aromatic compound. It is also possible to control the composition distribution and make the vinyl aromatic compound exist uniformly by devising the method of adding the 7-mer into the polymerization system.

Polymerization and copolymerization reactions are usually carried out at a reaction temperature of θ to 150° C., but conditions that deactivate active lithium terminals or conditions that cause gel formation due to crosslinking are not preferred. The polymerization reaction can be carried out by a batch polymerization method, a continuous polymerization method, or a combination thereof.

Next, in the present invention, the amide compound used to react with the polymer having an active lithium terminal to obtain a modified polymer containing a functional group is a compound having the structure of the above general formula, and examples thereof are as follows. Examples include ■-cyclohexyl-2-pyrrolidone, 1-methyl-2-pyrrolidone, 1-
Ethyl-2-pyrrolidone, l-propyl-2-pyrrolidone, 1-butyl-2-pyrrolidone, 1,5-dimethyl-
2-pyrrolidone, 1-methoxyethyl-2-pyrrolidone, 1-methyl-2-piperidone, 1,4-dimethyl-2
-piperidone, 1-isopropyl-2-piperidone, ■
Examples include -isopropyl-5,5-dimethyl-2-piperidone, 1-methyl-2-pyrrolidone and -methyl-2-piperidone are preferred, and 1-methyl-2-pyrrolidone is particularly preferred.

When the specific amide compound used in the present invention comes into contact with a polymer having active lithium terminals, it reacts almost quantitatively, and the reaction conditions are usually in the range of 25 to 150°C and reaction time of 1 second to 3 hours. Selected. The reaction proceeds approximately stoichiometrically.

In the present invention, it is preferred that at least 25% by weight, preferably 40% by weight or more of all polymer molecules be modified with the above-mentioned functional groups.

It is also possible for a part of the polymer to have a branched structure, and such a branched structure is introduced to improve the low-temperature flow and processability of the polymer. Manufacturing techniques for creating a branched structure include copolymerizing a small amount of a difunctional or higher monomer, such as vinylbenzene, or copolymerizing a portion of the active terminal with a trifunctional monomer such as silicon tetrachloride or tin tetrachloride. A method of reacting with an active halogen compound, a polyepoxy compound, a polyester, etc. having a higher molecular weight is adopted. If these branched structures are contained in an extremely large amount, they may cause the modified conjugated diene polymer to lose its characteristics, so the branched structure should be set within a range that maintains the performance characteristics depending on the desired performance. is preferred.

The modified conjugated diene polymer obtained in the reaction solvent by the above production method is processed by adding an antioxidant such as 2,6-tert-butyl-p-cresol after a predetermined reaction. Perform post-processing such as separating the coalescence, washing, and drying,
The desired polymer can be obtained. Further, in a step before the above-mentioned post-treatment, it is also possible to add a rubber extender oil such as paraffinic, nastenic, aromatic, etc. and use it as a masterbatch.

In the conjugated diene rubber composition for tires of the present invention, the specific functional group-containing modified conjugated diene polymer is used in an amount of 30 to 90% by weight, preferably 40 to 85% by weight of the raw rubber component. Ru.

When the amount used exceeds 80% by weight, there is almost no difference from the modified conjugated diene polymer alone, while when it is less than 30% by weight, when comparing the modified and non-modified polymers, 1. There is virtually no difference in performance.

Next, in the conjugated diene rubber composition for tires of the present invention, the rubbery polymer constituting the raw material rubber together with the above-mentioned [I] modified conjugated diene polymer is [II] natural rubber or cis-1,4 bond. 1 liter of polyisoprene rubber-like polymer selected from polyisoprene rubber having an amount of 90% or more, and [ml polybutadiene rubber or styrene-butadiene having a styrene content of 3 to 50% by weight] One or more butadiene-based rubbery polymers selected from copolymer rubbers.

The total amount of the raw rubber in [I] to [ml is 100 parts by weight, and the raw rubber in [■] and [ml] each accounts for 5 to 65% by weight, preferably 10 to 60% by weight of the raw rubber.

Natural rubber or cis-1 as the raw rubber component of [II],
In the conjugated diene rubber composition for tires of the present invention, polyisoprene rubber having a 4-bond content of 90% or more has vulcanizate physical properties such as heat resistance, tensile strength, and bending resistance, as well as roll processability and extrusion processability. It has the effect of making processing properties such as green strength and tack desirable, and this effect is significant in tread applications for large tires and passenger car tires, carcass applications, and sidewall applications.

The raw rubber component [■] is polybutadiene rubber or styrene-butadiene copolymer rubber having a styrene content of 3 to 50% by weight. Examples of polybutadiene rubber include high-cis polybutadiene rubber with a cis-1,4 bond content of 80% or more, low-cis polybutadiene rubber with a lithium-based catalyst, and furthermore, high-cis polybutadiene rubber with a cis-1,4 bond content of 80% or more, and low-cis polybutadiene rubber with a 1.2-vinyl bond content of 30 to 85%. Polybutadiene rubber with medium to high vinyl content is used. In addition, styrene-butadiene copolymer rubbers include those made by emulsion polymerization and those made with a lithium catalyst in which the amount of vinyl bonds in the butadiene portion is 10 to 80%, and the styrene content is in the range of 3 to 50% by weight. If the styrene content exceeds 50% by weight, the abrasion resistance, low-temperature properties, and heat resistance will deteriorate, which is undesirable. a, 100℃
) is in the range of 30 to 150, glass transition temperature is 1110℃
Preferably, the temperature is in the range of -20°C.

The polybutadiene rubber and styrene-butadiene copolymer rubber used have different molecular weights, molecular weight distributions, and degrees of branching depending on the purpose of the tire rubber composition of the present invention.

[I[[]'s raw material rubber component balances the physical properties of the vulcanizate, such as tensile strength, abrasion resistance, wet skid properties, and bending resistance, with the raw material rubber component of [I] in the tire rubber composition of the present invention. It is used to improve processability and control processability such as roll processability and extrusion processability, and this component is particularly used in treads, sidewalls, bead parts, etc. for passenger car tires.

Further, in the present invention, the weight average glass transition temperature of the raw material rubbers [I] and [II] is in the range of -95 to -40°C.

In the present invention, the weight average glass transition temperature of the raw material rubber is a value expressed by the following formula.

Tgm = Σ-jX Tgi/ΣWi However, Tgm: Weight average glass transition temperature Tgi
: Glass transition temperature of component i (measured value by DSC) Wi: Weight fraction of component i The weight average glass transition temperature of the raw rubber is appropriately selected depending on the intended use of the tire rubber composition. For example, raw rubber used for the treads of snow tires and studless tires, where low-temperature performance is important, preferably has a weight-average glass transition temperature in the range of -95 to -70°C, while wet skid resistance and handling Raw material rubber for the treads of high-performance tires and racing tires, where stability is important, has a weight-average glass transition temperature of -65 to -40°C.
The tread range is preferably from -90 to -50 for other passenger JG tires and large tires.
Preferably, it is in the range of °C. Further, the raw material rubber for the composition of each part of the tire other than the tread is also selected from the range of -95 to -40°C depending on the intended use. The glass transition temperature of the raw rubber is a factor that greatly affects the performance of each part of the tire, and for example, in the tread, it is related to rolling resistance performance, abrasion resistance, wet skid resistance, etc. Further, when the weight average glass transition temperature of the raw rubber exceeds 140° C., the low temperature properties deteriorate.

The conjugated diene rubber composition for tires of the present invention is characterized in that raw rubber having a specific structure as described above is used in a specific formulation. It can be put to practical use by blending commonly used carbon black, rubber extender oil, vulcanizing agent, and other rubber compounds.

The above [I], [II], [ml, [17]
In addition to the requirements of [V] and [VI] below:
: [V] Contains 30 to 120 parts by weight of carbon black per 100 parts by weight of raw rubber, [VI] Contains 5 parts by weight of rubber extender oil per 100 parts by weight of raw rubber.
A composition satisfying the requirement of containing up to 80 parts by weight constitutes a preferred embodiment of the present invention.

In the conjugated diene rubber composition for tires of the present invention,
Carbon black per 100 parts by weight of raw rubber, 30
It contains up to 120 parts by weight, preferably 35 to 100 parts by weight. As carbon black, it is preferable to use furnace black with high reinforcing properties, and SAF, l
The properties of the vulcanized rubber vary depending on the use of particle sizes such as 5AF, HAF, FEF, and SRF grade, and those with various struts, but in the conjugated diene rubber composition for tires of the present invention, iodine adsorption is Amount 30-20hg
/g, DBP oil absorption is 60-160cm2/100
It is preferable to use carbon black having a nitrogen specific surface area of 30 to 150 I12/g, either alone or in combination of two or more, depending on the required performance. If the amount of carbon black is less than 30 parts by weight per 100 parts by weight of raw rubber, the reinforcing effect will be small and the tensile strength etc. will not be sufficient, while if it exceeds 120 parts by weight, impact resilience and heat resistance will deteriorate, which is not preferable.

In the conjugated diene rubber composition for tires of the present invention,
The rubber extender oil is contained in an amount of 5 to 80 parts by weight, preferably 5 to 60 parts by weight, per 100 parts by weight of raw rubber. As the rubber extender oil, aromatic, naphthenic, or paraffinic extender oils are used depending on the use of the rubber composition of the present invention. For tread applications of studless tires and snow tires where low-temperature performance is important, and for carcass applications where heat resistance is important, naphthene-based or paraffin-based rubber extension oils are used, and handling stability is required. In terms of applications, methods such as using a relatively large amount of aromatic rubber extender oil are widely practiced.

If the rubber extender oil is less than 5 parts by weight, the effect of improving the dispersion of carbon black by the rubber extender oil is difficult to exhibit, while if it exceeds 80 parts by weight, tensile strength, abrasion resistance, heat resistance, etc. will deteriorate, which is undesirable. .

The vulcanizing agent used in the composition of the present invention mainly contains sulfur, and peroxides and sulfur-donating substances can also be used. The vulcanizing agent is preferably used in an amount of 0.05 to 5 parts by weight per 100 parts by weight of raw rubber.

Furthermore, in the composition of the present invention, various rubber compounding chemicals may be used as necessary. These rubber compounds include vulcanization aids such as stearic acid and zinc white, various types of vulcanization accelerators such as sulfecium, thiuram, and guanidine, amine and phenol anti-aging agents,
There are various chemicals such as ozone deterioration inhibitors, processing aids, and tackifiers. 1 Raw material rubber 10
It is used in a range of 0.05 to 10 parts by weight per 0 parts by weight.

The composition of the present invention is prepared by mixing and kneading the above-mentioned components using an internal mixer, an open roll, etc. of a known rubber kneading machine, and molding the composition through processes such as extrusion. is formed and finally vulcanized at a temperature of 130 to 200°C for 10 to 60 minutes.

The conjugated diene rubber composition for tires of the present invention has excellent impact resilience and heat resistance, and has an improved balance of wear resistance and wet skid resistance compared to compositions using conventional raw material rubber. At the same time, it has good processability, so there is a high degree of freedom in formulating formulations, and in some cases,
By adjusting the type and amount of carbon black and rubber extender oil, it is possible to achieve impact resilience and heat resistance equivalent to rubber compositions using conventional raw material rubber, and to greatly improve abrasion resistance and wet skid resistance. Improving the width is also part of Kaishu.

The conjugated diene rubber composition for tires of the present invention is particularly suitable for treads for various tire applications such as fuel-efficient tires, all-season tires, high-performance tires, studless tires, and snow tires. It can also be used for carcass, bead parts, etc., taking advantage of its excellent balance between vulcanizate physical properties and workability.

[Example] Examples and comparative examples are shown below. They are illustrative of the invention and are not intended to limit its scope.

In the examples, measurements of polymer structure, physical properties of vulcanized products, etc. were carried out according to the methods shown below.

Mooney viscosity is 1 using the L rotor in the usual way.
Measured at 00°C.

The styrene content was determined by ultraviolet absorption spectroscopy.
Calculated from the absorption based on the phenyl group at 62 mm.

The amount of vinyl bonds in the butadiene moiety was determined by measuring the spectrum using an infrared spectrophotometer and calculating the microstructure using the Hampton method.

Glass transition temperature was determined using DEC and ASTM-034.
The temperature change in specific heat was measured according to No. 17-75, and the extrapolated temperature (Taf) was taken as the glass transition temperature.

The tensile strength of the vulcanizate was measured according to JIS-8301.

The repulsion was measured using a Lübke repulsion device, and JIS
- Measured at 70°C according to -6301.

For heat resistance, use a Gutdrich Flexmeter.
Starting temperature 50℃, load 26 bonds, displacement 5.715
The measurement was performed under the conditions of 180 rpm and a rotational speed of 180 rpm, and the difference between the sample temperature after 20 minutes and the starting temperature was used as an index of heat resistance.

The abrasion resistance was measured using a Pico machining tester.

Wet skid resistance was measured using a device manufactured by the British Road Research Institute.

Processability was judged based on the roll operability and extrusion processability of the blend. Roll processability was evaluated using a 6-inch test roll based on the ability to wrap the compound, operability, etc. The evaluation criteria are: A is a product that has good wrapping and is easy to operate without sticking to the roll surface; D is the lowest rank is a product that does not wrap around the roll and is difficult to handle; B is the middle rank; The order was C.

Extrusion processability was determined using a Brabender Plastograph equipped with a Garvey die extruder, based on the shape 1 surface texture of the extrudate. The evaluation criteria is that the best rank is A if the surface texture is smooth and the edges are well cut, the lowest rank is D if the surface texture is rough, there are uneven extrusions, and the shape of the edges is poor, and the middle ones are B and C. The order was as follows.

In Examples and Comparative Examples, polymers shown in Tables 1 to 4 were used.

BR-A-BR-G, 5BR-D-SER shown in Table 1
- all include BR (polybutadiene rubber) and 5BR (styrene-butadiene rubber) modified with a specific cyclic amide compound, and BR-a-BR shown in Table 4
-c, BR unmodified to 5BR-d-SBR-
, SDR, and is a sample for comparison.

These samples were prepared by the method shown below.

Sample BR-A uses cyclohexane as a solvent, butadiene concentration is 16%, and ■-butyllithium is used as butadiene 100%.
Tetrahydrofuran was continuously supplied from section F to the first reactor at a rate of 0.05g per 100g of butadiene, and the internal temperature of the reactor was maintained at 90 to 100°C.
The polymer solution, which had completed the polymerization reaction, was continuously taken out from the upper part of the reactor and supplied to the second reactor. The average residence time of the reaction solution in the first reactor is 60
It was a minute. The temperature of the second reactor was maintained at 90°C, and the 1-
0.0 methyl-2-pyrrolidone per 100g of polymer
74 g of the cyclic amide compound was continuously fed and reacted to introduce a functional group. The polymer solution thus obtained was added with 2,6-tert-butyl- as a stabilizer.
P-cresol was added at a rate of 0.5 g per 100 g of polymer, and the solvent was removed by heating to obtain a polymer.

Sample BR-a was obtained in the same manner as sample BR-A except that methanol was used instead of the cyclic amide compound.

Samples BR-B, 5BR-E, and 5BR-J were prepared by the same continuous polymerization method used to obtain sample BR-A, and a cyclic amide compound was reacted. In preparing each of these samples, the amount of vinyl in the butadiene moiety was controlled by increasing or decreasing the amount of the polar compound tetrahydrofuran, the Mooney viscosity was controlled by the amount of n-butyllithium, and the amount of styrene was controlled by changing the supply ratio of butadiene and styrene. The content was controlled. Sample BR-B used 1-cyclohexyl-2-pyrrolidone as a cyclic amide compound.

Moreover, samples BR-b, 5BR-e, and 5BR-j corresponded to samples BR-B, 5BR-E, and 5BR-J, respectively, and methanol was used instead of the cyclic amide compound.

Sample BR-C used cyclohexane obtained by the batch polymerization method shown below as a solvent, and added 0.2 g per 100 g of 1,3-butadiene to a 15% solution of 1,3-butadiene.
Butyllithium 0 per 100g of 1,3-butadiene
．． 040g was added, and the temperature inside the reactor was maintained at 30 to 35°C, and the reaction was carried out for 12,020 minutes. After the polymerization reaction is completed, the polymer 10
0.071 g of 1-methyl-2-piperidone per 0 g was added and reacted for 10 minutes. 2,6-tert-butyl-p-cresol was added as a stabilizer to the polymerization solution thus obtained at a rate of 0.5 g per 100 g of the polymer, and the solvent was removed by heating.

Sample BR-c was prepared in the same manner as BR-C was obtained, using methanol instead of the cyclic amide compound.

In addition, samples 5BR-D, 5BR-G, 5BR-1
(For 5BR-, in the same batch polymerization method as that used to obtain sample BR-C:, the vinyl amount was adjusted by changing the amount and type of polar compound, and the styrene content was adjusted by changing the ratio of butadiene and styrene. The Mooney viscosity was completely adjusted with the amount of butyllithium, and 1-methyl-2-pyrrolidone was reacted as a cyclic amide compound to obtain a modified polymer.

Samples 5BR-d, SBR-g, 5BR-h,
5I3R- is a polymer containing no functional groups using methanol in place of 1-methyl-2-pyrrolidone.

Furthermore, 5BR-F was obtained by the following method.

Sample BR-C: A styrene-butadiene copolymer with active lithium terminals was produced by the same batch polymerization method as that used to obtain sample BR-C, and then 172 equivalents of F was produced per mole of active lithium terminals.
Active lithium by adding f1 (1/8 mole) of tin tetrachloride as a coupling agent to couple a part of the polymer to make it branched, and then adding 1-methyl-2-pyrrolidone as a cyclic amide compound. A modified polymer was obtained by reacting 1.0 mol with respect to the terminal (0.5 mol with respect to the original active lithium terminal).

2, as a stabilizer to the polymerization solution thus obtained.
Polymer 1 of 6-tert-butyl-p-cresol
The solvent was removed by heating.

As a result of analysis using G, P, and C, the proportion of branches branched by tin tetrachloride was 47%.

Sample 5BR-f is an unmodified polymer obtained by polymerizing in the same manner as obtaining Sample 5BR-F, coupling with tin tetrachloride, and then reacting with methanol without using a cyclic amide compound. It is.

In addition, as the raw material rubber for [II] and [III],
Commercially available raw rubbers shown in Tables 2 and 3 were used.

Example 1, Comparative Example 1 According to the formulation shown in Table 5, a rubber composition having the blend ratio shown in Table 6 was kneaded and mixed using a pressure kneader, and the resulting unvulcanized product was rolled and processed. Extrusion processability was evaluated. Further, the material was cured at 145° C. for an appropriate period of time, and the physical properties of the vulcanized material were evaluated.

The results are shown in Table 6.

As is clear from Table 6, in the blend formulation defined in the present invention, the composition using polybutadiene modified with a functional group exhibits excellent processability, and the physical properties of the vulcanizate include impact resilience and heat generation property. Excellent. On the other hand, compositions using unmodified polybutadiene have poor impact resilience and heat resistance.

Table 5 Polymer - 100 parts by weight Carbon black N339 50 parts by weight Aromatic oil 5 parts by weight Zinc Flower
31 parts stearic acid
2 parts by weight Antioxidant 331) 1 part value @ 1.8 parts by weight Vulcanization accelerator CZ2) 1.2 parts by weight 1) High temperature reaction product of diphenylamine and acetone 2) N-cyclohexyl-2-penzothiazyl Sulfenamide Example 2, Comparative Example 2 A rubber composition with the composition shown in Table 7 was prepared in the same manner as in Example 1 in the same manner as the formulation shown in Table 5, and the processability and physical properties of the vulcanizate were evaluated. did. The results are shown in Table 7.

As shown in Table 7, the composition of the present invention exhibits superior impact resilience and heat resistance compared to the comparative composition.

Example 3, Comparative Example 3 A rubber composition having the composition shown in Table 9 was mixed and kneaded in the same manner as in Example 1 using the formulation shown in Table 8, and the processability and physical properties of the vulcanizate were evaluated. The results are shown in Table 9.

As is clear from Table 9, the composition using the styrene-butadiene rubber modified with the specific functional group of the present invention as a raw material rubber has excellent impact resilience and heat resistance, and also has good wet skid resistance and abrasion resistance. In addition, the processability of the unvulcanized compound is also excellent.

Table 8 Polymer-10
0 parts by weight Carbon black N330 70 parts by weight 3 parts by weight Stearic acid 2 parts by weight Anti-naming agent 81ONAI) 1 part by weight Sulfur
1,75 parts by weight vulcanization accelerator N57)
1.4 parts by weight total
21f3.65 parts by weight 1) N-isopropyl-N
'-Phenyl-p-phenylenediamine? ) N-tert-butyl-2-benzthiazylsulfenamide [Effects of the Invention] The conjugated diene rubber composition for tires of the present invention comprises a conjugated diene rubber composition having a cyclic amide compound of 4. This is a tire rubber composition that uses three types of raw material rubber: a modified conjugated diene polymer monomer obtained by reaction with a polymer, a polyisoprene thread ball composite rubber, and a polybutadiene polymer rubber, and contains no unvulcanized material. In addition to having good processability, it has excellent rebound +71 properties and heat resistance, and the balance between these and abrasion resistance and wet skid resistance is improved compared to conventional compositions, making it suitable for tire treads, undertreads, and carcass. It is suitably used in various parts of tires such as sidewalls, bead parts, etc., and can also be used in other vulcanized rubber applications by taking advantage of its performance, so it has great significance in the T industry.

Claims (1)

[Scope of Claims] [I] 30 to 90% by weight of the raw material rubber contains (a) at least one conjugated diene compound, or a conjugated diene compound and a vinyl aromatic compound in a hydrocarbon solvent using an organolithium compound as a polymerization initiator; There are polymers with active lithium terminals obtained by polymerizing group compounds, and general formulas ▲mathematical formulas, chemical formulas, tables, etc. , Y represents an oxygen atom or a sulfur atom, and n represents an integer of 3 to 4) or -( in the above general formula)
One of the hydrogen atoms of the polymethylene chain represented by CH_2)-
(b) Mooney viscosity (ML_1_+_4, 100°C) is 30 to 150 (c) Glass transition temperature (Tg) is -100 to It is a conjugated diene polymer with a temperature of -20°C, and [II] 5 to 65% by weight of the raw material rubber is one type selected from natural rubber or polyisoprene rubber with a cis-1,4 bond content of 90% or more. [III] 5 to 65% by weight of the raw rubber is one or more selected from polybutadiene rubber or styrene-butadiene copolymer rubber having a styrene content of 3 to 50% by weight, [ IV] The total amount of the raw material rubbers [I] to [III] is 100 parts by weight, and the weight average glass transition temperature of the raw material rubbers [I] to [III] is -95 to -40°C. A conjugated diene rubber composition for tires, characterized by: