JPS61225229A - Modifier rubber composition - Google Patents

Abstract

PURPOSE:The titled composition excellent in green strength and moldability and capable of giving a vulcanizate excellent in strength properties, fatigue resistance and resiliency, comprising polyisoprene rubber modified with a Lewis acid, COOH group-containing polyisoprene rubber, etc. CONSTITUTION:100pts.wt. polyisoprene of a cis 1,4-bond content >=90%, etc., are dissolved in an organic solvent so that the concentration may be 1-30wt%. This solution is mixed with 0.1-5pts.wt. Lewis acid such as SnCl4 and reacted at -20-100 deg.C for 2min-10hr by using such a modifying condition that the glass transition temperature can be increased by 0.3-2.7 deg.C as compared with that of the starting polyisoprene and the Wallace plasticity can be increased by 2-35 points as compared with that of the starting material to obtain a Lewis acid-modified polyisoprene rubber (A). 100pts.wt. butadiene rubber having a vinyl bond content of 0-98% and a trans-1,4-bond content of 0-95% in a state dissolved in an organic solvent or in a like state is kneaded with 0.01-20pts.wt modifier such as maleic anhydride in the presence of heat or a peroxide to obtain a COOH group-containing butadiene rubber (B). 1-99pts.wt. component A is mixed with 99-1pt.wt. component B.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention improves the green strength and vulcanization of the carbon-containing unvulcanized product by mixing Lewis acid-modified polyisoprene rubber and carboxyl group-containing butadiene rubber. This invention relates to an invention that improves both the rebound modulus and abrasion resistance of a product.

(Prior Art) Conventionally, rubbers into which carxyl groups have been introduced are used as rubbers for the purpose of obtaining rubber compositions with improved green strength, for example, hydroxamylkloride such as maleic anhydride and terephthalohydroxamylchloride acid. How to react acids (
Special Publication No. 48-10635) is known. Furthermore, a reaction in which polyisoprene rubber is treated with a Lewis acid such as 5nC1a is known for the purpose of obtaining a rubber composition with improved rebound properties.

However, these modification reactions cannot improve green strength, rebound resilience, and abrasion resistance in a well-balanced manner, and are particularly insufficient in meeting the performance requirements of tire materials.

(Problems to be Solved by the Invention) Therefore, the inventor of the present invention has conducted various studies in order to develop a rubber material with excellent green strength, tensile stress, rebound modulus, and abrasion resistance. The inventors have discovered that the desired object can be achieved by mixing a modified I-lisoprene rubber and a butadiene-based rubber containing xyl groups, and have thus arrived at the present invention.

(Ninth Means for Solving the Problems) That is, the present invention provides a modified rubber composition comprising a polyisoprene rubber modified with a Lewis acid and a carboxyl group-containing butadiene rubber. be.

Polyisoderenco 9 modified with Lewis acid in the present invention
The rubber can be obtained by treating a solution of polyimprene rubber in an organic solvent or a polyisoprene rubber cement after polymerization with a Lewis acid.

The polyisoprene rubber used as a raw material here is preferably polyisoprene with a ratio of cis-1.4 bonds of 90 or more, which is polymerized using a Ziegler type catalyst or a lithium-based catalyst. ◎Solvents include benzene, toluene, etc. Aromatic solvents such as butane, hexane, etc., cycloparaffinic solvents such as cyclohexane, 710% hydrocarbon solvents such as cycloform, ethylene dichloride, etc., alone or in combination. It can be used as However, the amount of solvents that are active against Lewis acids, such as alcohols, ketones, and ethers, is limited. The concentration of rubber in solution is 1-3
It is appropriately determined within the range of 0% by weight. Further, it is desirable that the water content in the solution is usually 400 ppm or less.

Generally known Lewis acids can be used in the present invention, and representative examples include metal or semimetal halides, such as Be, LAz, and s+.

P, So Tl, V, Fe, Zn, Gas
Gem As, Se, Zr*Nb.

Mo, CcL Snt Sb+ T@, Ta, W
, Hg, Bl, U or other elements such as PO9SeO-
These include halides of oxygen-element combinations such as 5O0SO2-VO, organic halides, and complexes thereof. More specifically, BF3. (CH,)2BP,
AtC1,,AtBr,e (c2u5)Azcz2
゜POCl,; TiCl2. VCl4. MoC1
6, (CH,)SnCt, T@Br4, etc., particularly preferably BF30(C2H5)2.5nC14°5b
Examples include Cj wct8nBr41BCIs, TeC2a, and the like.

The amount of Lewis acid required for modification cannot be generally specified because it is greatly affected by the type of solvent, water in the solution, and other coexisting substances, but it is usually 0.01 to 0.000 parts by weight per 100 parts by weight of rubber.
5 parts by weight. In addition, by coexisting an appropriate amount of a compound having active hydrogen such as trichloroacetic acid, tribromoacetic acid, water or methyl alcohol, or a halide such as t-butyl chloride or benzyl chloride,
It is possible to significantly reduce the amount of Lewis acid. The reaction temperature during treatment with Lewis acid is not particularly limited, and is usually -20°C to 100°C, preferably 10°C to 6°C.
It is 0°C. The reaction time is not particularly limited,
Usually, it is set appropriately between 2 minutes and 10 hours. A Lewis acid is added to a solution of polyisoprene rubber and treated for a specified period of time with stirring.The reaction is stopped and the rubber is coagulated by adding a large amount of alcohol or hot water, followed by washing and treatment. A modified rubber is obtained by drying.

The above modification conditions with Lewis acid result in a glass transition temperature of 0.3°C to 2.0°C compared to the polyisoprene rubber before modification.
．． It is desirable to select such that the temperature rises by 7°C and the warp/less plasticity increases by 2 to 35 points. If the increase in the glass transition temperature or the increase in Wallace plasticity is lower than the above range, the improvement in rebound resilience and heat generation property is insufficient, and if it is higher than the above range, the rebound modulus will decrease and heat generation will increase. This will cause performance deterioration. Further, it is desirable that the conditions for modification with Lewis acid are selected so that the generation of ruple is as small as possible. If the amount of glue in unmodified polyisoprene is significantly increased (for example, 101 or more) compared to the unmodified polyisoprene, processability will be deteriorated.

In the present invention, the cal-xyl group-containing butadiene-based rubber means that even in a solution of butadiene-based rubber dissolved in an organic solvent,
Alternatively, it is a rubber obtained by introducing a carboxylic group in a rubber mixer in the absence of a solvent.

Examples of the butadiene rubber include polybutadiene rubber, styrene-butadiene copolymer rubber, butadiene-piperylene copolymer rubber, butadiene-acrylonitrile copolymer rubber, butadiene-isoprene-acrylonitrile copolymer rubber, and the like. It is of course possible to use two or more of these in combination. These butadiene-based rubbers are selected depending on the application, but polybutadiene rubber (hereinafter sometimes referred to as BR) or styrene-butadiene copolymer rubber (hereinafter sometimes referred to as SBR) is the most representative for tires. It is both effective and highly effective. BR is prepared by solution polymerization using a conventional catalyst such as a Ziegler type catalyst or an organic alkali metal catalyst, and has a vinyl bond content of 0 to 98%, and a lance 1.4 bond content of O to 95%. Examples include: Examples of SBR include those prepared by ordinary emulsion polymerization or solution polymerization, and have a styrene bond content of 5 to 40% by weight and a vinyl bond content of the butadiene moiety of 0 to 98% by weight.

The carboxyl group introduction reaction method is not particularly limited, but specific examples include maleic anhydride addition reaction with heat or in the presence of peroxide (CA'79 (2) 66
43Z), method of reacting hydroxamylkloridic acid such as FClxamylchloridic acid (JP-A-48-10635), addition reaction of 3-carboxylphenylmaleimide (KauchRsz)
lna 19748-10 Chavchich, T
5tal), a method of introducing a carboxyl group by reacting with carbon monoxide in the presence of a metal carbonyl (CA'77
(12) 76298P), 4-cal? Xyl-7
Carboxyl group introduction reaction using enyl-1.2.4-triazoline-3,5-dione (JP-A-49-86477
), etc.

The solvent and reaction conditions (temperature, pressure, 1 hour) used in the carboxyl group introduction reaction are generally selected from the same range as in the modification reaction with Lewis acid described above, but more specifically, depending on the reaction method. It is sufficient to adopt the conditions described in the above-mentioned documents and patents.

The amount of the modifier used in the carboxyl group introduction reaction is not particularly limited, but is usually per 100 parts by weight of rubber. 0.01 to 20 parts by weight, preferably 0.1 to 20 parts by weight
It is 10 parts by weight.

The mixing ratio of the Lewis acid-modified polyisoprene rubber and the carboxyl group-containing butadiene rubber is appropriately selected from the range of 1 to 99% by weight for the former and 99 to 1% by weight for the latter, depending on the purpose. For tires, the former is preferably 50 to 95% by weight, and the latter 50 to 5% by weight.

The method of mixing rubber in the present invention is not particularly limited, but
Usually, a method is used in which the polymer solution after the modification reaction is mixed using a stirrer or using various comb kneaders.

In addition, in particular, Cargon plastic, resin, and various process oils may be mixed in advance with modified polyisoprene rubber and/or cargexyl group-containing butadiene rubber to form a Cargen master patch or an oil master patch, and then the rubbers are mixed together. You can also do it.

(Effect of the invention) The rubber composition of the present invention can be used as a vulcanizing agent, a vulcanization accelerator, a vulcanization aid,
The unvulcanized compound obtained by mixing with conventional rubber compounding agents such as reinforcing agents and softeners, and optionally other conventional rubbers, exhibits excellent green strength and is therefore extremely easy to mold. This vulcanizate has excellent strength properties, fatigue resistance, rebound properties, and abrasion resistance, and is used not only for general purposes, but also for applications that require these properties, such as passenger car tires, trucks, and tires. , large tire carcass for passing,
Suitable for applications such as treads, sidewalls, bead fillers, inner liners, various anti-vibration rubbers, industrial belts, and hoses. Note that the rubber composition of the present invention can also be used in the form of latex for ordinary latte and drink applications.

(Example) Next, the present invention will be specifically explained using examples.

The methods for analyzing the rubber on each side, the methods for preparing unvulcanized rubber compounds and vulcanized products, and the methods for testing their physical properties are as follows.

〔Glass-transition temperature〕

Daini Seiko Kin High Sensitivity Differential Scanning Calorimeter (DSC) SSC-
560, and was determined from the inflection point of the measurement curve.

[Pumu Wallace plasticity]

100℃ using Wallace Ravid Blastmeter
Measure with friends.

[Amount of calxyl group introduced into rubber]

After purifying and removing the low-molecular components in the gum, the measurement was performed by neutralization titration (back titration with sodium methylate/hydrochloric acid).

[Preparation of unvulcanized rubber compound]

The modified rubber was cross-mixed in a small Banbury mixer with various compounding ingredients other than sulfur and vulcanization accelerator in the following formulation, and sulfur and vulcanization accelerator were added to the resulting mixture on a small roll. A rubber unvulcanized compound was prepared by kneading.

Mixing prescription (parts by weight) Cis-polyisoprene rubber 100 -
-cispolytadiene rubber 10
0 - Vinyl polybutadiene rubber --
100HAF carbon 50 50 5
0 Aromatic oil 5 5 5 Zinc oxide 5 3 ゛3 Stearic acid 2 2
2 Sulfur 2.5
1.5 1.0 (vulcanization accelerator) N-isopropyl-N'-phenyl-p-7 enylenenoamine 1.0
1.0 1.0 [Green strength] The unvulcanized rubber compound was press-molded at 100°C for 5 minutes to form an unvulcanized sheet with a thickness of 2 mm, and a dumbbell-shaped JIS No. 3 test piece was punched out. °C, 500m/ml
The value of tensile stress at an elongation of 500 inches when a tensile test is conducted at a tensile speed of n.

[Tensile test]

Press vulcanize the unvulcanized compound at 145°C (160°C for the vinyl polybutadiene compound) for a predetermined time.
A dumbbell-shaped No. 3 test piece specified in JIS-K 6301 was punched out as a thick sheet and 500 mm/mm at 25°C.
The tensile speed was mln.

[Repulsion modulus]

The vulcanized product obtained by heating the unvulcanized mixture at 145°C (160°C for the vinyl polybutadiene mixture) for a predetermined period of time was heated at 25°C using a Danro and Ptorign meter.
It was measured with

[Pico wear]

It was measured using a Guttori-Chi type Pico abrasion tester in accordance with ASTM D-2228.

Example 1 Polyisozolempum (cis 1.4 bonds g8%) 160I
4 i! The Lewis acid and cocatalyst listed in Table 1 were dissolved in dehydrated benzene and stirred in a glass closed container (seven-paraple flask) at 25°C under a nitrogen atmosphere, and the Lewis acids and cocatalysts listed in Table 1 were added as benzene solutions. After reacting under the conditions shown in the table, 100+d of methanol was added to stop the reaction.

The obtained rubber solutions are designated as A and B.

On the other hand, polybutadiene rubber (98% of cis 1.4 bonds) 1
4 for 60.51! was dissolved in benzene, and each of the compounds listed in Table 2 was added as a methanol solution at 60°C under a nitrogen atmosphere while stirring in a glass sealed container (7) Rubble flask). After reacting for 3 hours, 36% HC120-
The reaction was stopped by adding 200 g of methanol in which was dissolved. The resulting carmexyl group-introduced polybutadiene rubber solution was labeled C.

Called D. Polyisoprene rubber solutions A and B and carboxyl group-introduced polybutadiene rubber solutions C and D were mixed in the proportions shown in Table 3. After that, the reaction solution was poured into the methyl alcohol of No. 41. Completely coagulate the product, and wash the coagulated material into small pieces. Then about 2.9 anti-aging agents (2,
6-di-tert-butyl-4-methylphenol)
A rubber composition was obtained by immersing the coagulated pieces in 3J of methyl alcohol containing the following ingredients, washing them, and drying them in a vacuum dryer overnight.

For comparison, the same benzene solution as above of unmodified polyisoprene rubber or a mixed solution of this and the same benzene solution as above or rubber solution C of unmodified polybutadiene rubber was treated in the same manner as above to obtain a rubber composition. Get things9.

Next, unvulcanized mixtures and vulcanized products were prepared using each comb composition, and their physical properties were measured. The results are shown in Table 3. Example 2 I-lisoprene rubber (98% cis 1.4 bonds) 1601
f: Dissolved in 4 J of dehydrated benzene and placed in a closed glass container (
Lewis acid and cocatalyst in the amounts listed in Table 4 were added as benzene solutions at 25°C under a nitrogen atmosphere while stirring in a 4' rubble flask) and reacted for 60 minutes.
The reaction was stopped by adding 00-methanol. The obtained comb solution is 8! The column was poured into methanol to coagulate it, and the coagulated material was washed as fine pieces. Sample E was then obtained by soaking the coagulated pieces in 3J of methanol containing 2I anti-aging agent (2,6-di-tert-butyl-4-methylphenol), washing and drying in a vacuum dryer overnight. , got F.

On the other hand, I ribtadiene comb (vinyl bond 70) 16
01 was dissolved in 4j of toluene and reacted under the reaction conditions listed in Table 5 under a nitrogen atmosphere while stirring in a closed glass container (seven paraple flask), and then the reaction solution was dissolved in 2.
6-ditertiary-butyl-4-methylphenol 1%
methanol solution 3! The rubber was completely coagulated and the coagulated material was washed in small pieces. Thereafter, samples G and H were obtained by drying in a vacuum dryer for a day and a night.

The obtained samples E-H were mixed in a small rubber mixer according to the formulations shown in Table 6, and the physical properties were evaluated in the same manner as in Example 1 together with the comparative examples.

From Tables 3 and 6, it can be seen that the samples of the present invention have a much better balance of green strength, rebound modulus, and pico wear amount than the comparative samples.

Claims (1)

[Claims] A modified rubber composition comprising a polyisoprene rubber modified with a Lewis acid and a carboxyl group-containing butadiene rubber.