JPH03188143A - Production of rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber composition excellent in heat resistance, dynamic properties and fatigue resistance by heating a mixture of a rubber component comprising an ethylene.alpha-olefin.nonconjugated diene copolymer rubber and/or a butyl rubber with a specified dinitrodiamine in a specified amount, adding a filler to the heated mixture and kneading the resulting mixture. CONSTITUTION:A mixture of 100 pts.wt. rubber component comprising an ethylene.alpha-olefin.nonconjugated diene copolymer rubber (e.g. Esprene 671 F, a product of Sumitomo Kagaku) and/or a butyl rubber with 0.1-5 pts.wt. at least one dinitrodiamine of the formula (wherein X is a bivalent acyclic aliphatic, cycloaliphatic or aromatic group; R<1> is H or X; and R<2> and R<3> are each H or 1-12C alkyl) [e.g. N,N'-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane] is heated to 120 deg.C or higher, a filler (e.g. carbon black) is added to the heated mixture, and the resulting mixture is kneaded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an ethylene/α-olefin/nonconjugated tsene copolymer rubber and/or butyl rubber composition. (More specifically, it is an ethylene/α-olefin/non-conjugated diene copolymer that has excellent heat resistance, excellent fatigue resistance not only at room temperature, but also in high temperature atmosphere, and has a low dynamic ratio. Rubber and/or butyl rubber compositions (related to this) The rubber composition of the present invention can be optimally used as, for example, highly durable anti-vibration rubber for automobiles and industries.

<Prior Art> A wide variety of anti-vibration rubbers are used in general transportation such as automobiles and motorcycles, as well as in industrial machinery, etc., to prevent noise and vibration. Special(ko,
In the automotive field, the performance of enodine has improved in recent years, and it has excellent heat resistance, has excellent fatigue resistance not only at room temperature but also at high temperature, and has the ability to prevent noise and vibration. There is an increasing demand for anti-vibration rubber that can provide a comfortable ride.

The characteristics that such anti-vibration rubber should have are (1) excellent heat resistance;

(2) Low dynamic magnification (dynamic modulus/static modulus) to prevent noise and vibration during high-speed running.

(3) Excellent fatigue resistance and durability against repeated external forces (2) at room temperature or high temperature atmosphere over a long period of time.

etc.

Of course, it is also important that static rubber properties such as compression set and tear strength are comparable to those of ordinary rubber.

As conventional anti-vibration rubbers, highly unsaturated rubbers such as natural rubber and styrene-butadiene rubber (SBR) are mainly used. This is because highly unsaturated rubbers such as natural rubber and SBR have the advantage of superior fatigue resistance and dynamic properties compared to low unsaturated rubbers. Saturated rubber is low unsaturated rubber,
For example, it is known that the heat resistance is inferior to that of butyl rubber and ethylene/α-olefin/non-conjugated diene copolymer rubber. This tends to be limited.

On the other hand, low unsaturated rubbers such as butyl rubber and ethylene/α-olefin/nonconjugated diene copolymer rubber exhibit excellent heat resistance, but have the disadvantage of poor fatigue resistance and poor dynamic properties against long-term repeated external forces. Therefore, it could not be used under severe external force or deformation conditions.

<Problems to be Solved by the Invention> Under such circumstances, the present inventors have developed a technology that has excellent heat resistance, fatigue resistance against repeated deformation E at room temperature and high temperature atmosphere, and excellent dynamic properties. The present invention was arrived at as a result of intensive studies with the main purpose of developing a rubber composition.

Here, dynamic characteristics are characteristics represented by the degree of change in the elastic modulus (dynamic elastic modulus), that is, the dynamic magnification (dynamic elastic modulus/static elastic modulus) when vibration is input in the high frequency range. For the purpose of vibration isolation, the dynamic magnification is required to be low.

Means for Solving the Problems> That is, the present invention provides a method for producing a rubber composition, characterized by including the following first step and second step.

First step, rubber component 100 consisting of ethylene/α-olefin/non-conjugated diene copolymer rubber and/or butyl rubber
A step of obtaining a heat-treated mixture by heat-treating a mixture containing 0.1 to 5 parts by weight of at least one type of dinitrodiamine represented by the following general formula (a) at a temperature of 120° C. or higher.

A second step is a step of blending a filler into the heat-treated mixture and kneading it to obtain a rubber composition.

General formula (a) (wherein, X is a divalent chain aliphatic group, cycloaliphatic group, or aromatic group, and may contain a halogen or oxygen in the group. R1 is a hydrogen atom, It is a chain aliphatic group, a cycloaliphatic group, or an aromatic group, but when X and R1 are both chain aliphatic groups, the desired atoms are connected to each other through R1. You may do so.

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).The details will be explained below.

The method of the present invention includes two steps, the first step and the second step, as essential steps.

The first step consists of a rubber component 10 made of ethylene/α-olefin/non-conjugated diene copolymer rubber and/or butyl rubber.
A heat-treated mixture is obtained by heat-treating a mixture containing 0 parts by weight and 0.1 to 5 parts by weight of at least one type of dinitrodiamine represented by the general formula (a) at a temperature of 120'C or higher. It is a process.

The rubber component used in the first step is ethylene/α
- Olefin/non-conjugated diene copolymer rubber and butyl rubber are used alone or together.

Examples of α-olefin, which is one of the constituent components of the ethylene/α-olefin/non-conjugated diene copolymer rubber, include fluoropylene, -butene, and 1-hexene. Further, as the non-conjugated diene, 5-methylene-2-norbolyne is used.

Examples include 5-ethylidene-2-norbornene, dicyclobenotanoene, and 1.4hexanoene.

The present invention (butyl rubber used herein refers to isoprene/isophthylene copolymer rubber and its bromine- or chlorine-modified l)
Refers to halogenated butyl rubber obtained from this.

Note that a mixture of 70% by weight or more of the above ethylene/a-olefin/nonconjugated diene copolymer rubber and/or butyl rubber and another rubber, such as natural rubber, may be used as the rubber component in the first step.

The present invention (the compound represented by the general formula (a) used herein)
Specific examples of the compounds listed below include the following compounds. In addition, the following examples (here, -Z is CH3 CH2CN02 CH.

(1) (2) (3) (4) (5) (6) Z -NH+CH, NH-Z Z -NH+CH2 piece NH-Z Z-NH+CH2 soup NH-Z Z -NH+CH2 piece old-Z Z -NH+C 'fbji NH-Z Z NH+CH2ji NH-Z (8) N02 (-CH2 dry NH+CH2) NH+C
HJ7NO2(9) No2+CH4NH(-C)1
2+-6NH+CH2e7NO2 is shown.

CH.

CH5 (]4) Z　-N(l-CH2淘N CH.

H-Z (48) Z N + Hz The amount of dinitrodiamines used is 0.1 to 5 parts by weight per 100 parts by weight of the rubber component. If the amount is less than this range, the effect of improving dynamic characteristics will be insufficient, and if it is more than this range, the effect will be saturated, resulting in uneconomical results.

A radical generator may be present in the first step. By using a radical generator, it is possible to further improve the fatigue resistance and dynamic properties of the target rubber composition. can.

Examples of the radical generator used here include 2-2 dithiobis-benzothiazole and organic peroxides. Organic peroxides are not particularly limited,
diallyl peroxide, dialkyl peroxide,
One or more types of organic peroxides such as peroxyesters and perketals can be used. Specific examples include benzoyl peroxide, 1-I di-t-butylperoxy 335 trimethylchlorohexane, di-t-butylperoxydiisofuropylbenzene, and dicumyl peroxide.

Examples include 2,5-dimethyl-2,51 di(t-butylperoxy) hexasan.

The amount of peroxide used is not particularly limited, but it is preferably used in an amount of 0.1 to 3 parts by weight per 100 parts by weight of the rubber component. Further, along with these organic peroxides, polyfunctional monomers such as ethylene dimethacrylate, trimethylpropane trimethacrylate, and triallyl isocyanurate can also be used, if necessary.

1st step (here, 1001 parts of rubber component = 30
A filler may be added in a proportion of parts by weight or less. As the filler, carbon black, silica, talc, calcium carbonate clay, etc., which have been conventionally used in the rubber field, are used, but carbon black is preferably used from the viewpoint of fatigue resistance. As the carbon black, for example, HAF, FEF, SRF black, etc. can be used without being limited by the degree of reinforcing property.

When a filler is used in the first step, the amount used must be 30 parts by weight or less per 100 parts by weight of the rubber component. If a filler exceeding the above range is used in the first step, the final rubber composition will be unsatisfactory in terms of its dynamic properties.

In the first step, a rubber component, dinitrodiamines,
and as necessary (accordingly, it is necessary to heat-treat the mixture containing the radical generator and filler at a temperature of 120° C. or higher).

A higher temperature at this time is preferable in terms of improving fatigue resistance and dynamic properties, but if the temperature is too high, oxidative deterioration of the rubber occurs, so it is preferable to complete the process at 220° C. or lower in 1 to 40 minutes.

However, in the first step (in which no filler is used and a radical generator is used), a heat treatment temperature of 100° C. or higher is sufficient.

Specifically, the heat treatment in the first step G refers to mixing the mixture at a temperature of 120°C or higher, or mixing the mixture at around room temperature, and then using an open oven or the like to heat the mixture for 120°C or more.
This is done by heating to a temperature of 0°C or higher.

For mixing, for example, an open roll, an internal kneader, an extruder, etc. are used.

Note that as a method for adding dinitrodiamines, dinitrodiamines may be dissolved in an organic solvent such as hexane, added to the rubber component as a solution, allowed to permeate, and then the organic solvent may be removed by evaporation.

The second step of the present invention is a step of blending and kneading the heat-treated mixed filler obtained in the first step to obtain a rubber composition.

The filler used in the second step is exemplified by the same fillers as those exemplified as the filler that can be used in the first step, and carbon black is most suitable. The filler used in the second step may be the same as the filler used in the first step, or may be different. The amount of filler used in the second step is such that the total amount of the filler used in the first step and the amount of filler used in the second step is the rubber component weight ratio normally used in the rubber industry. The range is controlled in two ways.

That is, the total amount is 3 parts per 100 parts by weight of the rubber component.
It weighs about 0 to 200 parts by weight.

The kneading carried out in the second step is carried out using equipment and conditions commonly used in the rubber industry, and is not particularly limited.

The rubber composition obtained in the second step can be blended with known vulcanizing agents and vulcanization accelerators commonly used in the rubber industry and vulcanized by known methods.

In addition, in the first step and/or the second step, compounding agents other than the filler of the present invention, such as process oil, zinc white, stearic acid, and processing aids, may be added.

<Examples> The present invention will be specifically explained below using Examples.
The present invention is not limited to these numbers.

Examples 1 to 6 and Comparative Examples 1 and 2 Table 1 [Mixing and heat treatment were carried out using a Banbury mixer with an internal capacity of 1.5 t under the first step conditions shown below. Next (this, as the second step), FEF was added to the obtained heat treated mixture.
100 parts by weight of black, paraffin process oil (
35 parts by weight of Diana PW-90 (registered trademark, manufactured by Idemitsu Kosan Co., Ltd.), 5 parts by weight of zinc white, and 1 part by weight of stearic acid were added and kneaded for 3 minutes at 160 to 170°C using a Banbury mixer. Note that parts by weight are values based on 100 parts by weight of the rubber component used (excluding the weight of extension oil) (the same applies hereinafter). After cooling the rubber composition thus obtained to room temperature, As vulcanization accelerators, 2.0 parts by weight of tetramethylthiuram disulfide, 2.5 parts by weight of dibenzothiazyl disulfide, and 1.2 parts by weight of sulfur were added, and 4 parts for oven rolls were added.
A compound was obtained by kneading at 0 to 70°C. The viscosity of this Compawood was measured by the method of JIS K6300. The compound was then processed using a hot press at 170° C. for 10 minutes to form a vulcanized sheet with a thickness of 2 mm. Various evaluations were performed using this vulcanized sheet. The tensile test and tear test were conducted according to the method of JIS K6301.Other evaluation methods are as follows.

Measurements were made using a tan δ viscoelasticity spectrometer at a temperature of 30° C. and an oscillation frequency of 25 Hz.

Dynamic magnification JIS K6383 Static elastic modulus (Ks) calculated based on measured values and dynamic elastic modulus (Kd, Oo measured at 30°C and 100 Hz using a viscoelastic spectrometer) ) ratio (Kd, oo/Ks).

Tensile fatigue properties: Using a bending fatigue tester manufactured by Monsando, the strain rate was O~1.
The number of extensions until breakage was measured under the condition of 50%.

The results are shown in Table IG.

Example 7 A mixture obtained by simmering under the same conditions as the first step of Comparative Example 1 was strained using an oven roll (40 to 60°C) to form a sheet approximately 5 mm thick, and heated in an oven at 160°C for 10 minutes. The first step was completed by processing. The operations and various evaluations after the second step were carried out in the same manner as in Examples 1 to 6. The results are shown in Table 1.

Examples 8 to 1] Mixing and heat treatment were carried out using a Banbury mixer with an internal capacity of 1.5 t under the first step conditions shown in Table 2. Under the second process conditions shown in Table 2 below, Bamba'J -
The mixture was kneaded using a mixer at 160 to 170°C for 3 hours. The following were used as vulcanization accelerators: 2.0 parts by weight of tetramethylthiuram disulfide and 2.5 parts by weight of dibenzothiazyl disulfide (2.0 parts by weight in Example 9), and (1.2 parts by weight of sulfur). Parts by weight were added and kneaded at 40 to 70°C using an oven roll to obtain a compound.The subsequent operations and evaluation were performed in the same manner as in Example 1.The results are shown in Table 2.

Comparative Example 3.4 Example 8~ except that the blending and kneading in the second step were not performed.
It was carried out in the same manner as in 11. The results are shown in Table-2.

<Effects of the Invention> As explained above, the present invention makes it possible to produce a rubber composition that has excellent heat resistance, fatigue resistance against repeated deformation at room temperature and high temperature atmosphere, and excellent mechanical properties. We were able to provide a way to do so.

that's all

Claims (4)

[Claims] (1) A method for producing a rubber composition, comprising the following first step and second step. First step: 100 parts by weight of a rubber component consisting of ethylene/α-olefin/non-conjugated diene copolymer rubber and/or butyl rubber and 0.1 to 5 parts by weight of at least one type of dinitrodiamine represented by the following general formula (a). A step of obtaining a heat-treated mixture by heat-treating a mixture containing 120° C. or more at a temperature of 120° C. or higher. Second step: A step of adding a filler to the heat-treated mixture and kneading it to obtain a rubber composition. General formula (a) ▲ Numerical formulas, chemical formulas, tables, etc. R^1 is a hydrogen atom, a chain aliphatic group, a cycloaliphatic group, or an aromatic group, but when X and R^1 are both chain aliphatic groups, R^1 Nitrogen atoms may be further connected to each other via 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. ) (2) The first step includes 100 parts by weight of a rubber component made of ethylene/α-olefin/nonconjugated diene copolymer rubber and/or butyl rubber, and 0.0 parts by weight of at least one dinitrodiamine represented by the general formula (a). Claim (1), which is a step of obtaining a heat-treated mixture by heat-treating a mixture containing 1 to 5 parts by weight, 30 parts by weight or less of a filler, and/or a radical generator at a temperature of 120°C or higher. the method of. (3) The method according to claim (2), wherein the filler used in the first step is carbon black. (4) The first step includes 100 parts by weight of a rubber component made of ethylene/α-olefin/nonconjugated diene copolymer rubber and/or butyl rubber, and 0.0 parts by weight of at least one dinitrodiamine represented by the general formula (a). The method according to claim 1, which is a step of obtaining a heat-treated mixture by heat-treating a mixture containing 1 to 5 parts by weight of a radical generating agent at a temperature of 100°C or higher.