JPS6225137A - Rubber composition - Google Patents

Abstract

PURPOSE:To provide a rubber composition having high loss tangent and decreased temperature-dependence of loss tangent without deteriorating the original characteristics of the base polymer and suitable for tire tread, by compounding a specific monomaleimide compound to a base polymer. CONSTITUTION:100pts.wt. of a rubber selected from natural rubber and synthetic rubber is compounded with 0.1-10pts.wt. of the monomaleimide compound of formula [R is OH, carboxyl, alkoxycarbonyl, (alkoxy-substituted) 1-18C alkyl, cycloalkyl, aryl, alkanol, aralkyl, anilino or H]. The monomaleimide compound is e.g. N-phenylmaleimide, N-(alpha-naphthyl)maleimide, N-(biphenyl-2-yl) maleimide, N-(2-fluorenyl)maleimide, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a rubber composition, in particular, a rubber composition having a small temperature dependence of a loss tangent (tan δ) value measured by animal viscoelasticity measurement.
The present invention also relates to a rubber composition having a high JAN δ value.

(Prior art) Recently, with the improvement of automobile performance, the paving of roads, and the development of expressway networks, the demand for pneumatic tires with high maneuverability has increased, and grip performance is particularly important. , represented by acceleration performance and braking performance. Therefore, the higher these characteristics are, the faster, more accurately and safely the vehicle can travel.

Conventionally, in order to obtain high grip performance, a styrene-butadiene copolymer rubber with a high styrene content (rubber with a high glass transition temperature) was selected as the tread rubber composition of a tire, or a process oil and carbon black with a high content were selected. Select the filled compounding system and check the JAN δ of the rubber composition.
I needed to increase the value.

Furthermore, as a method for improving grip performance deterioration due to temperature rise, Japanese Patent Application Laid-Open No. 187011/1987 describes a method of combining a heptamine such as 1,3-butadiene, styrene, or isoprene with diphenyl-2-methacryloyloxyethyl phosphide. It is described that a copolymer rubber obtained by copolymerizing an acrylate or methacrylate compound containing a diphenyl phosphate group such as ate or diphenyl-2-acryloyloxyethyl phosphate is used.

(Problem to be solved by the invention) However, in order to obtain high grip performance, styrene
If the styrene content of the butadiene copolymer is increased, the grip performance will certainly increase, but as the temperature of the rubber increases as the tire runs, the JAN δ value will decrease and the grip performance will drop rapidly. On the other hand, although high filling of process oil and carbon blank improves the performance of the grill knob, there is a limit to high filling, and the problem is that high filling of these will significantly reduce fracture properties and wear resistance. There was a point. Furthermore, the above-mentioned method for improving the grip performance deterioration due to temperature rise is not only inapplicable to natural rubber, but also depends on the manufacturing conditions. There was a problem that the characteristics were damaged.

(Means for Solving the Problems) As a result of intensive research in order to solve the above-mentioned problems, the present inventors have found that by blending a specific monomaleimide compound into rubber, it is possible to impair the original properties of the polymer. Not, jan
The present invention was accomplished by confirming that a conventionally unobtainable rubber composition having a small temperature dependence of the δ value and a high JAN δ value can be obtained, and the problems can be solved.

That is, the present invention provides the following general formula (wherein R is a hydroxyl group, a carboxyl group, an alkoxycarbonyl group, The number of carbon atoms that may be substituted with an alkoxy group is 1
0.1 to 10 parts by weight of at least one monomaleimide compound represented by ~18 alkyl groups, cycloalkyl groups, aryl groups, alkanol groups, aralkyl groups, anilino groups, or hydrogen atoms. This is a rubber composition.

The synthetic rubber used in the present invention includes synthetic polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, etc., and may be used alone or as a blend. Natural rubber may also be used alone or in blends with synthetic rubbers.

Examples of the monomaleimide compound used in the present invention include N-phenylmaleimide, N--(α-naphthyl)maleimide, N-(biphenyl-2-yl)maleimide, N-(-2fluorenyl)maleimide)', N-
(-4ethoxycarbonylphenyl)maleimide, N-
(4-ethoxyphenyl)maleimide, N-(-4hydroxyphenyl)maleimide, N-(4-carboxylphenyl)maleimide, 4-(11-carboxyl-n
-undecyl)maleimide, N-methylmaleimide, N
-Tertiary butylmaleimide, N-stearylmaleimide, N-cyclohexylmaleimide, N-orthotolylmaleimide, N-hensylmaleimide N-(5-hydroxy-1-naphthyl)maleimide, N-(4-hydroxy- 1-naphthyl)maleimide, N-anilinomaleimide, N-hydroxymethylmaleimide, maleimide, etc., and these may be used alone or in combination of two or more.

Furthermore, when conducting the tests shown in Examples, monomaleimide compounds were synthesized and used in accordance with known synthesis methods. The blending amount of the monomaleimide compound is 0.1 to 10 parts by weight. If it is less than 0.1 parts by weight, the effect will be lost, and if it exceeds 10 parts by weight, not only will the increasing effect be lost, but it will also have an adverse effect on various physical properties after vulcanization.

The above maleimide compound is added to the double bond of the rubber molecule during kneading or vulcanization of the rubber composition, and by modifying the rubber molecule, increases the slip resistance of the main chain of the rubber molecule. This has the effect of reducing the decrease in the JAN δ value.

In the present invention, in addition to the monomaleimide compound described above, compounding agents commonly used in the rubber industry, such as softeners, anti-aging agents, vulcanization accelerators, vulcanization accelerators, and vulcanizing agents, are used as necessary. It can be blended within the range of usual blending amounts.

Further, the rubber composition of the present invention can be used in all kinds of rubber products such as tires, conveyor belts, hoses, etc.

(Example) The present invention will be explained below with reference to Examples.

First, various monomaleimide compounds used in Examples were synthesized by the methods described in the following Reference Examples.

2 with reflux condenser, thermometer and stirrer with mercury seal
110.3 g (1,125 mol) of maleic anhydride was added to a solution obtained by charging 400 ml of acetone and 69.8 g (0.75 mol) of aniline into a 14-bottle flask.
A solution prepared by dissolving 350 ml of acetone was added dropwise over 2 hours while stirring at room temperature, and the mixture was further stirred at 50°C for 4 hours. Next, after cooling to room temperature, acetic anhydride 191
．． 3 g (1,875 mol) and sodium acetate 18.
5g (0,225 mol) and again at 50°-60°
The reaction was completed by stirring at °C for 6 hours. After cooling to room temperature, 650 ml of water was added little by little to crystallize the target product, which was then filtered, washed thoroughly with water on a filter paper, and then heated at 50°C.
95.1 g of N-phenylmaleimide having a melting point of 87° to 88°C (yield = 73.3
%）I got it.

Reference example 2 α-naphthylamine 107.3g (0
By performing the same operation as in Reference Example 1, except using 131.2 g of N-(α-naphthyl)maleimide (
A yield of 78.4% was obtained.

Reference Example 3 Synthesis of N-(biphenyl-2-yl)maleimide 126.8 g of 2-phenylaniline (0,7
By performing the same operation as in Reference Example 1 except that 5 mol) was used, N having a melting point of 140.5° to 142.5°C was obtained.
-(biphenyl-2-)maleimide 150.2g (
A yield of -80.4%) was obtained.

Seal 1st l± 2-aminofluorene 135.8g (instead of aniline)
By performing the same operation as in Reference Example 1 using 0.75 mol), 168.4 g of N-(2-fluorenyl)maleimide having a melting point of 184.0° to 186.5°C was obtained.
(Yield=86.0%) was obtained.

p-ethoxycarbonylaniline 12 instead of aniline
By performing the same operation as in Reference Example 1 except that 3.8 g (0.75 mol) was used, 110.5° to 112.
127.5 g of N-(4-ethoxycarbonylphenyl)maleimide with a melting point of 13 °C (yield -69.4
%) was obtained.

Reference Example 6 Synthesis of N-(4-ethoxyphenyl)maleimide Instead of aniline, 102.8 g of Kano ethoxyaniline (0.75 g
N having a melting point of 132.0' to 135.0°C was obtained by performing the same operation as in Reference Example 1, except that mol) was used.
-(4-ethoxyphenyl)maleimide 133.6g (
Yield=82.1%) was obtained.

81.8 g of p-aminophenol instead of aniline
N-(4-hydroxyphenyl)maleimide having a melting point of 158.0° to 160.2°C was obtained by performing the same operation as in Reference Example 1, except that (0.75 mol) was used.
4 g (yield -69.4%) was obtained.

Instead of aniline, p-aminobenzoic M102.8g (
By performing the same operation as in Reference Example 1 except that 0.75 mol) was used, N-(4-carboxylphenyl)maleimide 95 having a melting point of 243.1'' to 246.0°C was obtained.
．． 4g (yield=58.6%) was obtained.

12-aminolauric acid 161.3 instead of aniline
N-(11-carboxyl-n-undecyl)maleimide having a melting point of 91.2' to 95.5°C was obtained by performing the same operation as in Reference Example 1 except that g (0,7,5 mol) was used. 144.1 g (yield -65.1%) was obtained.

Instead of aniline, 40% methylamine aqueous solution 58.1
By performing the same operation as in Reference Example 1 except for using methylamine generated by heating (0.75 mol) of N- Methylmaleimide 28.4g (Yield=34.1%
) was obtained.

Instead of aniline, 54.8 g of tertiary butylamine (0
, 75 mol) and subjected to the same reaction and post-treatment as in Reference Example 1. The resulting viscous liquid was distilled under reduced pressure to obtain N-tertiary butyl with a boiling point (1 mmHg vacuum) = 65°C. 35.2g maleimide (yield=30.7%
) was obtained.

Reference Example 12 Instead of aniline, 201.8 g of stearylamine (0
, 75 mol) was carried out in the same manner as in Reference Example 1 to obtain 215.4 g of N-stearylmaleimide (purity 50%) having a melting point of 94'' to 109°C (yield = 82.3%). I got it.

Instead of anilyl, 74.3 g of cyclohexylamine (
104.6 g of N-cyclohexylmaleimide (i(NZ=77
．． 9%).

80.3 g (0.7 g) of orthotoluidine instead of aniline
By carrying out the same operation as in Reference Example 1 except that 5 mol) was used, 96.1 g (yield = 68.5%) of N-orthotolylmaleimide having a melting point of 736 to 76 °C was obtained. .

80.3g of benzylamine (0.7g instead of aniline)
By performing the same operation as in Reference Example 1 except that 5 mol) was used, 103.7 g of N-benzylmaleimide having a melting point of 65.0' to 68.0°C (yield = 73.9%) was obtained.
I got it.

3 with reflux condenser, thermometer and stirrer with mercury seal
In a 00 ml four-loaf flask, add 14.0 g of 5-amino-1-naphthol hydrochloride (mixed well in a mortar).
0,0716 mol), maleic anhydride 7.0 g (0,0
716 mol) and 6.5 g (0,
0,766 mol) was charged, and the
After heating and melting for an hour, it was washed with 200ml of 60°C warm water. Next, 300 ml of water was added dropwise to the filtrate obtained by extraction with warm ethanol at 60°C and hot filtration at 20°C to form a precipitate, which was then filtered to obtain a precipitate. 4. Recrystallize the resulting precipitate from ethanol/water to obtain N-(5-hydroxy-1-naphthyl)maleimide having a melting point of 235°C.
2g (yield=24.6%) was obtained.

Instead of 5-amino-1-naphthol hydrochloride, 4-amino-1-naphthol hydrochloride 14.0 g (0,071
After performing the same operation as in Reference Example 16 except that 6 mol) was used, N having a melting point of 200°C was purified by reprecipitation using an acetic acid/water system instead of recrystallization from an ethanol/water system. -(4-hydroxy-1-naphthyl)maleimide 4.9 g (yield = 28.7%) was obtained.

10.3 g (0,0716 mol) of phenylhydrazine hydrochloride instead of 5-amino-1-naphthol hydrochloride
By performing the same operation as in Reference Example 16, except for using , 4.3 g of N-anilinomaleimide (yield = 31.9%) having a melting point of 255° to 258°C was obtained.

Reference Example 19 N-Hydroxymethylmaleimide 49.0 g (0.5 mol) of maleimide was placed in a four-loaf flask equipped with a reflux condenser, a thermometer, and a stirrer with a mercury seal.
After adding 50ml of 35% formalin aqueous solution,
While stirring at room temperature, add 5% aqueous sodium hydroxide solution 2.
1II! ! was added dropwise, and the mixture was further stirred at room temperature for 4 hours.

After filtering the generated crystals, they were thoroughly washed with water on a filter paper, and then dried with hot air at 50°C for 48 hours to obtain a crystal of 100.5° to 103°C.
．． 40.9 g (yield = 64.4%) of N-hydroxymethylmaleimide having a melting point of 0°C was obtained.

5 cases 1-19. Comparative Example 1 100 parts by weight of styrene-butadiene rubber, 3 parts by weight of aromatic oil, 6 parts by weight of AF force-bon black
5 parts by weight, 3 parts by weight of zinc white, 2 parts by weight each of the monomaleide compounds obtained in Reference Examples 1 to 19, and varying amounts of 1,3-diphenylguanidine, 2-mercaptobenzothiazole, and sulfur. The material was vulcanized to almost equal modulus, and tan δ was measured at 20° C. and 80° C. under the condition of a dynamic strain of 1% using a viscoelasticity measuring tester manufactured by Rheometrics.

The results are shown in Table 1. For comparison, a case in which no monomaleimide compound was blended was evaluated in the same manner and is also listed in Table 1. Examples 1 to 19 in the table correspond to reference examples 1 to 19.
Nineteen monomaleimide compounds were each used.

Examples 20-25. Comparative Example 2 SBI with 35% styrene content? l5 to 100 parts by weight
AF force - 20 parts by weight of bomb black, 80 parts by weight of SAF carbon blank, 100 parts by weight of aroma oil, 1 part by weight of stearic acid, 1 part by weight of anti-aging agent (IPPD),
Reference Examples 2, 3, 6.10.14 and Size 2051515-13 ( whose tread portion was made of a rubber composition containing 5 parts by weight of each of 16 monomaleimide compounds)
Tires 2251515-13 (for front wheels) and 2251515-13 (for rear wheels) were manufactured. These tires were used for 20 laps around a circuit of 4.41 km per lap, and the strap time was measured between the first lap time and the lap time difference at the start of the 20th lap. For comparison, the time difference between tires and tires that do not contain a monomaleimide compound and the best time are expressed as an index, with the best time set as 100.

The results are shown in Table 2. The larger the value, the higher the grip performance.

(Effects of the Invention) As explained above, the rubber composition of the present invention has a structure in which a specific amount of a specific monomaleimide compound is blended into the rubber component, so that the tan δ in the high temperature region is large and the 20'Ctan δ and 80℃tan δ
The temperature dependence of tan δ, which is expressed as the difference between Since it can be suppressed, grip performance is improved.

Claims (1)

[Claims] 1. For 100 parts by weight of at least one rubber selected from the group consisting of natural rubber and synthetic rubber, the following general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (in the formula R has 1 carbon number, which may be substituted with a hydroxyl group, a carboxyl group, an alkoxycarbonyl group, or an alkoxy group.
0.1 to 10 parts by weight of at least one monomaleimide compound represented by ~18 alkyl groups, cycloalkyl groups, aryl groups, alkanol groups, aralkyl groups, anilino groups, or hydrogen atoms. A rubber composition characterized by: 2. The monomaleimide compound is N-phenylmaleimide, N-(α-naphthyl)maleimide, N-(biphenyl-2-yl)maleimide, N-(2-fluorenyl)maleimide, N-(4-ethoxycarbonylphenyl) maleimide, N-(4-ethoxyphenyl)maleimide,
N-(4-hydroxyphenyl)maleimide, N-(
4-carboxylphenyl)maleimide, N-(11-
Carboxyl-n-undecyl)maleimide, N-methylmaleimide, N-tertiary butylmaleimide, N-stearylmaleimide, N-cyclohexylmaleimide, N
-orthotolylmaleimide, N-benzylmaleimide,
N-(5-hydroxy-1-naphthyl)maleimide, N
-(4-hydroxy-1-naphthyl)maleimide, N-
The rubber composition according to claim 1, which is anilinomaleimide, N-hydroxymethylmaleimide, or maleimide.