JPH03170539A - Preparation of rubber composition containing dinitrodiamine - Google Patents

Abstract

PURPOSE:To improve the processability by compounding a rubber component with a carbon black and dinitrodiamine. CONSTITUTION:100 pts.wt. rubber component comprising a natural rubber or a blend thereof with a synthetic rubber, the natural rubber being the major component, is compounded with 10-150 pts.wt. carbon black and 0.1-10 pts.wt. dinitrodiamine of the formula at 120-220 deg.C, and then compounded further with 0.3-5 pts.wt. stearic acid at 50-120 deg.C. In the formula, X is a divalent linear aliph., cycloaliph., or arom. group, and may contain a halogen or oxygen atom; R<1> is H, a linear aliph., cycloaliph., or arom. group, and when X and R<1> are both linear aliph., two nitrogen atoms may combine with each other through R<1>; and R<2> and R<3> are each H or a 1-12C alkyl group, and they may combine with each other to form a ring.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for producing a rubber composite sole containing dinitrodiamines, and particularly to a method for producing a rubber composition with improved processability. .

BACKGROUND ART In recent years, in the automobile industry, there has been an increasing demand for improvements in various physical properties of various products and parts.

For example, if we take rubber products such as tires and anti-vibration rubber,
Pursuing economic efficiency, such as lower fuel consumption, improved durability, and longer product life, as well as improving ride comfort, such as reducing vibration and noise, are becoming important issues. For this reason, it is important to improve the dynamic properties such as resilience, heat resistance, and dynamic magnification of the vulcanized rubber used in such rubber products.

As methods for improving dynamic properties, methods such as improving the microstructure and molecular weight distribution of rubber, improving the formulation of organic rubber chemicals and reinforcing agents, and adding dynamic property improvers are also known. Among these, the method of adding a dynamic property improver is attracting attention because it can improve dynamic properties more easily than other methods and can also be applied to natural rubber.

As such a dynamic physical property improver, JP-A No. 63-239
Publication No. 42 describes the following general formula (1) (wherein, X is a divalent chain aliphatic group, a cycloaliphatic group, or an aromatic group,
The group may contain halogen or oxygen. R1 is a hydrogen atom, a chain aliphatic group, a cycloaliphatic group, or an aromatic group, but when X and R1 are both chain aliphatic groups, the nitrogen atoms are further bonded to each other via R'. May be connected. R2 and R3 are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and R2 and R3 may be combined to form a ring. ) have been proposed. These dinitrodiamines impart excellent dynamic properties to rubber, so
It is being applied to tires and anti-vibration rubber.

However, these dinitrodiamines have a coupling function between rubber and carbon black, and also have a function of improving the dispersibility of carbon black, so rubber compounds to which they are added have a Mooney viscosity tends to increase and processability tends to deteriorate. For this reason, there is a problem in that molding defects sometimes occur, which hinders the manufacture of rubber products.

(Problems to be Solved by the Invention) Against this background, the present inventors have developed a rubber composition that incorporates the dinitrodiamines while making maximum use of the dynamic properties that are characteristic of the dinitrodiamines. As a result of intensive research to improve the processability of

<Means for Solving the Problems> In other words, the present invention provides a method for producing a rubber composition containing carbon black and dinitrodiamines represented by the general formula [■] above, in which carbon black and dinitrodiamines are first added to the rubber component. The present invention provides a method for producing a dinitrodiamine-containing rubber composition with excellent processability, which comprises blending a dinitrodiamine-containing rubber composition with stearic acid and then blending stearic acid.

As the dinitrodiamines of the general formula [I] used in the present invention, the following compounds are specifically exemplified. In the following examples, -2CH, -C}l, -C-NO, CH, is ? show.

(1) Z-NIHCII2NH-Z (2) Z-N
ll+CH2+T-NH-Z(3) Z-Nll+CH
J7-NH-Z(4) Z-Nl{+CH2}-N}I
-Z(5) Z-NH+CH2inertN}I-Z(6) Z
-NIHCL%NH-Z C}I. CH3 (7) Z-NH-CH2-CH-CH2CH-CH*
-N}I-Z(8) Not-{-CH,←NH+C}
12+TNH-{-CH2+T-NO. 2 (9) NO2+ct+2←N }l+c H JrN
h+c H t+rN O ,2 NO. NO ■ (10) C11. +-CI! -CH2-N}1+CH
2iNH-CI! , -C}I-C}I. NO ■
No. (11) C11,-C}1-CH2-N}I+CH2
．． )-rNI{-CH,-CH-C}I. CH. CH3 {14} z−N+CL+T−N−Z {16} Z− N }! {}NH- 2 Nll-Z (18) Z-NH-CHbeE}CL-NH-Z (20) CH,N}l-Z N 0 2+C }I 2+-f-N }INN H100C }1 No. (25〉 Z- N HEN H - Z NH-2 (27) NOa+co2KeN }luN H+C H 2 catty No
, CH, 8r (35) '2-N }I-C}I 2+C }I 2-N H2 (37) (38>(39> (40) z- N H@NH - Z l-N }I{ yC H ,{}-N H-ZNO2+
CH KanoNH{}CH2{yNH-{-CH. Tsubo NO,z
- No{yo{yNH-2 NH-Z NH-1 NO2 NOx NO, NO, Thus, the substituent X in the general formula [I] is 2
It is a chain aliphatic group, a cyclic aliphatic group, or an aromatic group, and can contain a halogen in the group as in Examples 33 and 34, and as in Examples 40 to 43. can contain oxygen in the base. Among these, those in which X is a chain aliphatic group, particularly a chain aliphatic group having 4 to 12 carbon atoms, are preferably used.

Further, R' in the general formula [I] is a hydrogen atom, a chain aliphatic group, a cycloaliphatic group, or an aromatic group, and X and R
When all of 1 are chain aliphatic groups, the above 23rd
Examples and 24th examples include those in which nitrogen atoms are further connected to each other via Rl and a ring is formed by XSR' and two nitrogen atoms.

Furthermore, R2'J3 and R3 in general formula [I] are
They may be the same or different, and each is a hydrogen atom or an alwyl group having 1 to 12 carbon atoms.

In addition, the above-mentioned 12th example, 13th example, 22nd example, and 30th example
As in the example, those in which R2 and R3 are combined to form a ring are also included.

Such dinitrodiamines may be blended into rubber in any form, including a single compound, a mixture of multiple compounds, a mixture with a carrier such as clay that does not affect the physical properties of the rubber, and furthermore, as described below. It can take the form of a mixture with various compounding agents. Therefore, it can be added to rubber in any of these forms.

The amount of dinitrodiamines used is not particularly limited, but is usually 0.1 to 10 parts by weight per 100 parts by weight of rubber.

In addition, as carbon plaque, various carbon blacks with different reinforcing properties that have been used conventionally, such as SA
F, ISAF, HAF, SPF, FEFSGPF, SR
F, MT, etc. can also be used in the present invention, and the type thereof is not particularly limited. The amount added is also not particularly limited, but is usually 10 to 100 parts by weight per 100 parts by weight of rubber.
It is 150 parts by weight.

In addition to natural rubber, rubbers that can be used in the present invention include polyisoprene rubber, styrene-butadiene copolymer rubber, polybutadiene rubber, acrylonitrile-butadiene copolymer rubber, isoprene-isobutylene copolymer rubber, and ethylene-propylene-diene rubber. Various synthetic rubbers such as polymeric rubber are exemplified, and these rubbers can be used alone or in a blend with different rubbers. Among these, natural rubber alone or a blend system with synthetic rubber mainly composed of natural rubber is preferable.

Carbon black and dinitrodiamines represented by the above general formula [r] are added to such a rubber fraction, and stearic acid is also added. One of the important aspects of the present invention is that stearin It's time to add acid. In other words, rubber components such as natural rubber and/or synthetic rubber,
By adding stearic acid after adding carbon black and dinitrodiamines, a rubber with low Mooney viscosity and excellent processability can be created while making the most of the dynamic properties characteristic of dinitrodiamines. A composition is obtained.

Stearic acid used in the present invention has conventionally been commonly used as a rubber compounding agent, but its addition is usually done before or almost simultaneously with carbon black.

According to such prior art, when the dinitrodiamines are blended with carbon black, the Mooney viscosity of the rubber compound becomes high.

On the other hand, by changing the timing of addition of stearic acid according to the present invention, that is, by blending stearic acid after blending carbon black and dinitrodiamines with the rubber component, it is possible to reduce the Mooney viscosity. The amount of stearic acid added is not particularly limited, but is usually 0.3 to 5 parts by weight per 100 parts by weight of rubber.

In the present invention, the compounding machine used for compounding the rubber can be one commonly used in the rubber industry, and is not particularly limited, but suitable examples include an open roll, a Banbury mixer, and a kneader.

Further, when compounding the rubber, carbon black and the dinitrodiamines are preferably compounded at a temperature of about 120 to 220° C., since the effect of improving the physical properties of the rubber is greater when compounded at a high temperature. On the other hand, stearic acid may be blended at a temperature similar to that of carbon black and dinitrodiamines, but the processability improvement effect is greater when blended at a relatively low temperature, so the temperature is approximately 50 to 120°C. It is preferable to mix it with

In the present invention, various other compounding agents commonly used in the rubber industry can also be used depending on the purpose. Typically, fillers, sulfur, peptizers, zinc white, various vulcanization accelerators, scorch retarder process oils, processing aids, anti-aging agents, antiozonants, waxes, etc. are used. The types, amounts, and order of compounding of these ingredients are as follows:
It can be selected as necessary and is not particularly limited in the present invention.

The rubber composite sole obtained by the present invention is preferably used, for example, in various parts of tires, particularly in tread parts, or as vibration-proof rubber. For example, a tire can be produced by applying this rubber composition to a tread or other member and shaping it by a method commonly used in the tire industry. Furthermore, this rubber composition can be formed into a suitable shape or bonded to metal to form a vibration-proof rubber.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. In the following examples, parts are by weight unless otherwise specified.

Further, the dinitrodiamines used in the examples are as follows, and are indicated by respective symbols below.

A: N,N'-bis(2-methyl-2-nitroprovir)-1,6-diaminohexane B: N,N'-bis(2-methyl-2-ditroprovir)-1,4-diaminobenzene Example 1 Toyo Seiki 250ml as a bumper mixer!
Using a lab blast mill, at an oil bath temperature of 170℃,
100 parts of natural rubber, 45 parts of HAF carbon black,
1 part of dinitrodiamines (A), 3 parts of aromatic process oil, and 5 parts of zinc white were added and kneaded for 5 minutes at a mixer rotation speed of 60 rpm. The temperature of the rubber at this time was 162°C.

Next, in a Laboplastomill with an oil bath temperature of 90°C, 3 parts of stearic acid and 1 part of sulfur were added. 5 parts of Nt-butyl-2-penzothiazylsulfenamide and 0.5 parts of tetramethylthiuram disulfide as vulcanization accelerators, 0.2 parts of N-(cyclohexylthio>phthalimide as a scorch retarder), and N as an anti-aging agent
-Phenyl-N'-1,3-dimethylbutyl-2 parts of p-phenylenediamine were added and kneaded for 3 minutes at a mixer rotation speed of 60 rpm. The temperature of the rubber at this time was 93°C. The Mooney viscosity of the compounded rubber thus obtained was measured.

Furthermore, after being vulcanized for 25 minutes at 145° C. using a vulcanization press, it was subjected to various tests. The respective test methods are as follows.

(1) Based on Mooney viscosity JIS K-6300, ML at 100℃, Yu4
was measured.

(2) Resilience It was measured using a Lübke type testing machine.

(3) Heat resistance ^ Measured in accordance with STM D-623-58. That is, using a Goodrich type heat generation tester, a load of 35
1bs, stroke 6.35m, frequency 180O r
pm, the temperature inside the tank is 40℃, and the exothermic temperature after 40 minutes (
The difference between the rubber temperature after 40 minutes and the initial rubber temperature was measured.

(4) 60°C tan δ (loss factor) Measured using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho under conditions of static load of 300 g, frequency of vibration of 50 Hz, and temperature of 60°C.

(5) Dynamic magnification Measured using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho at a temperature of 25° C. and a vibration frequency of 100 Hz.

Example 2 Dinitrodiamines (A) were converted into dinitrodiamines (B)
A rubber assembly was made in the same manner as in Example 1, except that the following was changed, and the same tests were conducted.

Comparative Example A rubber composition was prepared in the same manner as in Example 1, except that 3 parts of stearic acid was not added in the second step and was mixed simultaneously with carbon black and dinitrodiamines (A) in the first step. A similar test was conducted.

The test results of Examples 1 and 2 and Comparative Example are summarized in Table-1.

Table 1 <Effects of the Invention> According to the present invention, processability, which has been a difficulty in the past, can be improved in the production of rubber composite soles containing dinitrodiamines represented by the general formula [I] and having excellent dynamic properties. Improvements will be made. That is, by changing the order of addition of stearic acid, the Mooney viscosity of unvulcanized rubber can be reduced, thereby eliminating troubles during the production of rubber products.

Claims (5)

[Claims] (1) Rubber components include carbon black and the following general formula [I] ▲Mathematical formula, chemical formula, table, etc.▼[I] (In the formula, X is a divalent chain aliphatic group, a cycloaliphatic group, or an aromatic It is a group group and may contain a halogen or oxygen in the group.R^1 is a hydrogen atom, a chain aliphatic group, a cycloaliphatic group, or an aromatic group, but if both X and R^1 are In the case of a chain aliphatic group, nitrogen atoms may be further connected to each other via R^1.R^2 and R^3
are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and R^2 and R^3 may be combined to form a ring. ) A method for producing a dinitrodiamine-containing rubber composition with excellent processability, which comprises blending the dinitrodiamines represented by the following formula, and then blending stearic acid. (2) The method according to claim 1, wherein the rubber component is natural rubber alone or a blend of natural rubber and synthetic rubber. (3) The method according to claim 1 or 2, wherein X in the general formula [I] is a chain aliphatic group having 4 to 12 carbon atoms. (4) A tire manufactured using the composition obtained by the method according to any one of claims 1 to 3. (5) A vibration-proof rubber manufactured using the composition obtained by the method according to any one of claims 1 to 3.