JPS60141706A - Modification of diene polymer rubber - Google Patents

Abstract

PURPOSE:To obtain modified titled rubber of improved resilience with its wet skid resistance intact, for use in tire tread etc., by the reaction between specific aromatic ketone compound and diene polymer rubber derived from polymerization using a catalytic system containing alkaline earth metal. CONSTITUTION:The objectivae modified rubber can be obtained by the reaction between (A) a diene polymer rubber derived from polymerization using a catalytic system containing alkaline earth metal (e.g. n-butyllithium-dibutylmagnesium-triethylaluminum-barium dinonylphenoxide system) and (B) an aromatic ketone compound of formula (R1 and R2 are each alkyl, cycloalkyl, alkenyl, alkoxy, amino, halogen, etc.; m and n are each integer 0 or 1-5) [e.g. 4,4'- bis(diethylamino)benzophenone].

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for modifying diene polymer rubber, and more specifically to a method for modifying diene polymer rubber, and more specifically, a method for modifying diene polymer rubber polymerized using a catalyst system containing an alkaline earth metal. The present invention relates to a method for modifying diene polymer rubber by reacting it with a group ketone compound.

In recent years, due to demands for lower fuel consumption and driving safety for automobiles, rubber materials with low rolling friction resistance and high wet skid resistance have been strongly desired as rubber for automobile tire treads.

However, these two characteristics are contradictory,
Various improvement methods have been proposed to harmonize these two characteristics. Among these, the use of polybutadiene or butadiene-styrene copolymer rubber, which has a high vinyl bond content in the microstructure of the butadiene unit part, improves wet skid resistance among the above two properties, but improves rolling friction resistance, strength properties, and durability. Abrasion resistance is also insufficient, and improvement is desired.

The present invention has been made in view of this background, and it is an object of the present invention to provide a method for modifying diene polymer rubber that increases rebound resilience, which is correlated with rolling friction resistance, without impairing wet skid resistance.

The object of the present invention is to use a catalyst system containing an alkaline earth metal (polymerized diene-based polymer rubber and a general substituted compound selected from alkenyl groups, alkoxy groups, amine groups, alkylamino groups, dialkylamino groups, halogens). This is achieved by reacting the group with an aromatic ketone compound represented by (5m and n each represent O or an integer from 1 to 5). By carrying out the method of the present invention, it is possible to fabricate a diene polymer rubber having a high trans L4 bond with low rolling friction resistance and improved strength properties, abrasion properties, and rebound resilience without impairing wet skid resistance. becomes.

When the catalyst system containing an alkaline earth metal used in the present invention is used to (co)polymerize a diene monomer, the microstructure of the diene monomer unit in the (co)polymer becomes a high trans L4 bond. It is an anionic catalyst system, for example (1) a complex consisting of 13a tertiary alkoxide/diptyl Mg disclosed in JP-A-52-48910, (2) an organic catalyst disclosed in JP-A-52-9090 etc. [where R is at least 1
are methyl or cyclohexyl groups, and the remaining R is Ct-
represents an alkyl group of S, a: b-99,5-8
8: 0.5-12 (in molar ratio). ] (3) 13 disclosed in JP-A-56-112916
a alcoholade or phenolate/organic Li or Mg
/composite initiator consisting of organic Kl, (4)% 1972-1
7591.30543.9 s O77, JP-A-1983-
112916. Examples include those disclosed in JP-A-57-98077, etc., but there are no particular limitations as long as the catalyst system can yield an active diene (co)polymer having a trans L4 bond content of at least 50L16.

The diene polymer rubber obtained using this catalyst system is L3-
Butadiene, isoprene 1,3-hentadiene, '2
．． Polymers or copolymers of conjugated diene monomers containing 3-dimethyl-L3-butadiene, L3-hexadiene, etc., styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, etc. that can be copolymerized with conjugated diene monomers. Examples include aromatic vinyl compounds containing , unsaturated nitriles such as acrylonitrile and methacrylonitrile, esters of (meth)acrylic acid, copolymer rubbers with vinylpyridine, etc.
It is not limited to these.

Specifically, polybutadiene rubber, polyisoprene rubber,
Examples include butadiene-styrene copolymer rubber and isoprene-styrene copolymer rubber.

The polymerization reaction may be carried out in exactly the same manner as in the case of anionic polymerization using a normal alkali metal-based catalyst, and the polymerization reaction is carried out using a hydrocarbon solvent, tetrahydrofuran.

It is carried out in a solvent that does not destroy the catalyst system, such as tetrahydropyra/dioxane.

Suitable hydrocarbon solvents are selected from aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons.

Especially C1-1. Propane, n-butane% i-butane, n-hentane, i-pentane, n-hexane, cyclohexane, fluorene, 1-butene, i-butane, trans-2-butene, cis-2-butene, Preferred examples include 1-pentene, 2-pentene, 1-hexene, benzene, toluene, xylene, and ethylbenzene.

The polymerization temperature and the amount of catalyst used are not particularly limited as long as they can be carried out according to conventional methods.

The Mooney viscosity of the resulting diene polymer rubber is not particularly limited, but preferably 20 to 150.

The aromatic ketone compounds used in the present invention include general alkyl groups, cycloalkyl groups, alkenyl groups, alkoxy groups, amino groups, alkylamino groups, dialkylamino groups, etc.
m and n are 0 or 1 to
Each represents an integer of 5. ), in which R and R2 are preferably one or more amine groups, alkylamino groups, or dialkylamino groups. For example 6-441-bis(dimethylamino)-benzophenone, 4
4'-bis(diethylamine)-benzophenone, 44
'-Bis(dibutylamino)-benzophenone, 441
-Diaminobenzophenone 4.41-dimethoxybenzophenone, 2,2. '&3'-Tetramebulpenzophenone% 4-dimethylaminobenzophenone and the like are mentioned as preferred compounds.

The amount of the aromatic ketone compound used is 0.05 to 10 mol per mol of active diene polymer rubber, preferably 0.
．． It is 2 to 2 moles. Since the reaction between the aromatic ketone compound and the active diene polymer rubber occurs rapidly, the reaction temperature and reaction time can be selected from a wide range, but generally range from several seconds to several hours at room temperature to 100°C.

The reaction may be carried out by bringing the active diene polymer rubber into contact with the aromatic ketone compound, for example, by polymerizing the diene polymer rubber using the catalyst system, and completing the polymerization reaction with the active polymer. Although a method of adding a predetermined amount of the aromatic ketone compound to a rubber solution is shown as a preferred embodiment, the method is not limited to this method.

After the reaction is complete, the modified diene polymer rubber can be coagulated using the same coagulation methods used in conventional solution polymerization rubber production, such as adding a coagulant from the reaction solution or steam coagulation, and the coagulation temperature is also particularly limited. Not done. For drying the crumb separated from the reaction system, a band dryer, an extrusion type dryer, etc., which are commonly used in the production of synthetic rubber, can be used, and the drying temperature is not particularly limited.

The modified diene polymer rubber obtained in this way has significantly improved rebound properties and is therefore a very useful rubber as a rubber material for fuel-efficient tire treads. Explain.

Example 1 Cleaned a stainless steel polymerization reactor with an internal volume of 21 cm.

After drying and purging with dry nitrogen, L3-butadiene 20
09, n-hexane 800× was added and mixed uniformly. Next, n-butyl Ll, dibutyl Mg, triethyl A7! ,
Catalyst composition (molar ratio) in order of Ba dinonyl phenoxide
is Ba / Mg / Li / AJ = 1 /
1.5/1.5/2, λ3-butadiene/
It was added so that n-butyl LI=300 (g/mmol). Thereafter, polymerization was carried out at 50°C for 15 hours.

After the polymerization reaction was completed, 30 mmol of 44'-bis(diethylamino)benzophenone was added and stirred for 5 minutes.
ml of methanol was added and the mixture was further stirred for 5 minutes. after that,
26-di-1-butyl-p-cresol (BHT)1.
The resulting polymer was taken out into a 5% methanol solution and coagulated. The separated polymer was dried under reduced pressure at 60°C for 24 hours.

The Mooney viscosity (ML1+, 100°C) of the produced polymer was 43, and the microstructure determined by Moléguchi's method using an infrared spectrometer was 17.1'% cis-L4 and 76.9% trans-L4. , vinyl 6.0cm.

Example 2 A polymer was obtained under the same conditions as in Example 1 except that 44'-bis(dimethylamino)benzophenone was used instead of 44'-bis(diethylamino)benzophenone.

9 Example 3 A polymer was obtained under the same conditions as in Example 1 except that the corresponding thiobenzophenone was used instead of 44-bis(diethylamino)benzophenone.

Example 4 A polymer was obtained under the same conditions as in Example 1 except that the amount of 3-butadiene used was 200.9 to 1849 and 16.9 of styrene was used. Mooney viscosity (ML) of the produced polymer
l+4.100'C) is 55, and the microstructure (of the butadiene unit) is cis L427.5%, trans 1,4
67.0, vinyl 5.5, and styrene content 3.9
%Met.

Example 5 Ba[
'(t-Buo)1.8 (OH)0.2] A barium salt with a composition of After polymerization at 50"C for 24 hours, 30 mmol of 44?-bis(diethylamino)benzophenone was added and stirred for 5 minutes. After that, 10-methanol was added and stirred for another 5 minutes, and the same as in Example 1 was carried out. A dried polymer was obtained.The resulting polymer had a Mooney viscosity of 51 and a microstructure of cis 1.417.
5 inch, trans 1,475.1 inch, vinyl 7.4 inch.

Comparative Example 1 A polymer was obtained under the same conditions as in Example 1 except that 44-bis(diethylamino)benzophenone was not added.

The Mooney viscosity of the produced polymer was 40, and the microstructure was almost the same as in Example 1.

Comparative Example 2 A polymer was obtained under the same conditions as in Example 4 except that 44'-bis(diethylamino)benzophenone was not used.

The resulting polymer has a Mooney viscosity of 53 and a microstructure.

The amount of styrene was almost the same as in Example 4.

Comparative Example 3 In Example 1, only n-butyl Ll was used as a catalyst in 1.
A polymer was obtained under the same conditions as in Example 1, except that 8 mmol of diethylene glycol dimethyl ether was used, and 0.5 mmol of diethylene glycol dimethyl ether was used, and the polymerization was carried out at 40° C. for 1 hour.

The resulting polymer had a Mooney viscosity of 50, and a microstructure of 412% cis L, 1,418.2% tra/s, and 69% vinyl.
It was 8th place.

Each of the polymer rubbers obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and the compounding agents listed in Table 1 were kneaded on a roll to prepare compounded rubber compositions. These were press-vulcanized under conditions of 160° C. for 25 minutes.

Table 1 Polymer rubber 100 parts by weight HAF carbon black 50 N Aromatic process oil 5 Zinc white rI&L3 3 tt Stearic acid 2 Sulfur yellow 2 Vulcanization accelerator 1 (N-oxydiethylene-2-benzothiazole Sulfenamide) The impact resilience of the vulcanizate was measured at 49°C using a Dunlop tributometer. Wet skid resistance was measured using a Votaple skid tester (manufactured by Stanley, UK).
C. using an ASTM E303-74 road surface (3M outdoor type B, black, Safety Walk) and expressed as an index with Comparative Example 1 as 100. Further, an abrasion test was conducted using a Pico abrasion tester, and the results were expressed as an index, with Comparative Example 3 being 100. The normal vulcanization physical properties are JISK630.
I followed 1. The above results are shown in Table 2.

13- Table 2 Note) (*) The higher the number, the better (#) The lower the number, the better Patent applicant Zeon Corporation 14- Procedures Amendment March 1989-27 1 Display of the case 1939 patent application No.? fire? ,? g 7 No. 2 Relationship with title of invention case Patent applicant 5, number of inventions increased by amendment 0 6 Subject of amendment 39-

Claims (1)

[Scope of Claims] Diene-based polymer rubber polymerized using a catalyst system containing an alkaline earth metal and general formulas: 1, cycloalkyl, alkenyl, alkoxy, amino, alkylamino, dialkylamino basis,
a substituent selected from halogen, m and n are 0 or 1;
Each represents an integer between ~5. ) A method for modifying diene polymer rubber, which comprises reacting with an aromatic keto/compound represented by: