JPS59106946A - Preparation of vulcanizable rubber compound - Google Patents

Abstract

PURPOSE:To enable the continuation of a kneading process, by directly kneading granular ethylene/alpha-olefin copolymer rubber, a filler, a softener and a vulcanizer in a twin-shaft extruder. CONSTITUTION:Copolymer rubber is an ethylene/alpha-olefin/polyene copolymer and one of which the mole ratio of ethylene and alpha-olefin is about 60/40-85/15, the polyene content is about 3-30 in the display of an iodine value and Moony viscosity ML1+4 (100 deg.C) is about 20-120 is pref. used and a granular one having a wt. per 100 particles of about 0.1-200g, pref., about 1-50g is used. The copolymer rubber is subjected to continuous kneading treatment by a twin-shaft extruder and the vulcanized rubber physical properties of the copolymer rubber molded product obtained by vulcanization molding is not inferior as compared with the one subjected to kneading treatment by a batch method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing vulcanizable rubber compounds. More specifically, the present invention relates to a method for producing a vulcanizable ethylene/α-olefin/polyene copolymer rubber compound.

Traditionally, fillers such as carbon black, silica, clay, talc, and calcium carbonate, softeners such as mineral oil,
When kneading and compounding a vulcanizing agent such as sulfur, a sulfur compound, or an organic peroxide into rubber, an oven mill such as a two-reel type or an internal mixer such as a Banbury mixer is used. However, all of these kneading methods are patch-type and require a lot of manpower for preparation for the kneading operation and post-processing, and are therefore inferior in economic efficiency. Furthermore, it cannot cope with the recent continuous molding and vulcanization processes.

By the way, ethylene/α-olefin/polyene copolymer rubber itself has excellent heat resistance, so rubber compounds using this copolymer rubber as a pace polymer can withstand high temperatures that cannot be achieved with other diene rubber compounds. Continuous vulcanization methods such as high frequency vulcanization method (UHIF method), hot air vulcanization method (HAv method), and powder vulcanization method (POM method) have been proposed because short-time vulcanization is possible. These are put into practical use in combination with a calendar molding method, a continuous molding method using various types of pressers, etc. However, as long as the kneading process, which is the previous stage, is a batch method in which only one state remains, the adoption of each of the continuous methods described above cannot result in true labor and energy savings. desired.

The present invention aims to solve this problem, and it has been found that this problem can be solved by directly kneading particulate copolymer rubber with various compounding agents in a twin-screw extruder. .

Therefore, the present invention relates to a method for producing a vulcanizable rubber compound, and the method for producing a vulcanizable rubber compound comprises particulate ethylene α
-Olefin/polyene rubber, filler, softener, and vulcanizing agent are directly fed to a twin screw extruder and kneaded continuously.

The copolymer rubber is made of ethylene and α-olefin, such as propylene, 1-butene, ■-pentene, 1-hexene,
-Methyl-1-pentene, 1-octene, 1-decene,
1-tetradecene, 1-octadecene, etc., preferably a copolymer of propylene and polyene, with a molar ratio of ethylene and α-olefin of about 60/40 to 85/1.
5. The polyene content is approximately 3 to 30 in terms of iodine value. Mooney viscosity MLI+4 (100℃) is approximately 20 to 1
20 is preferably used.

In this copolymer, the polyenes include 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,
Chained non-conjugated dienes such as 5-hexadiene, 6-methyl-1,5-hebutadiene, 7-methyl-1,6-octadiene, cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene , 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2
- cyclic non-conjugated dienes such as norbornene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-flubornadiene, 1,3.7 Examples include trienes such as -octatriene and 1,4.9-decatriene, among which cyclic nonconjugated dienes, particularly dicyclopentadiene and 5-ethylidene-2-norbornene, are preferably used.

The copolymer rubber made of each of these copolymer components is used in the form of particles having a specific size, that is, a weight of about 0.1 to 200 particles, preferably about 1 to 50 particles. If the size of this particulate copolymer rubber is too large, it will not be possible to obtain a rubber compound that will be uniform and give a vulcanizate with the desired physical properties, while if the particle size is small, it will not be possible to obtain a rubber compound that is uniform and gives a vulcanizate with desired physical properties. It is difficult to manufacture, and even if it were possible to do so, it would be uneconomical, and therefore, a size within the above range is generally used. Such particulate copolymer rubber is disclosed, for example, in the US patent ff!, which describes the invention filed by the present applicant. It can be easily produced using a pelletizer that simultaneously performs the removal of the polymerization solvent and the pelletizing step according to the method described in No. 3,586,089.

As fillers, SRF, GPF, F'11E
F, HAF.

Carbon black such as SAF, SAF, FT XMT and reinforcing fillers such as finely divided silicic acid, or non-reinforcing fillers such as light calcium carbonate, heavy calcium carbonate, talc and clay can be used. These fillers are generally copolymer rubber 10
It is used in a proportion of about 20 to 200 parts by weight per 0 parts by weight.

Examples of softeners include process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petroleum substances such as petrolatum, coal tar such as coal tar pitchnat, castor oil, linseed oil, rapeseed oil, Fatty oils such as coconut oil, tall oil, waxes such as beeswax, carnauba wax, and lanolin, fatty acids or their metal salts such as ricinoleic acid, palmitic acid, barium stearate, calcium stearate, and zinc laurate, petroleum resins. , ``Synthetic polymer substances such as atactic polypropylene and coumaron indene resin are used. These softeners are generally used in an amount of about 5 to 150 parts by weight per 100 parts by weight of the copolymer rubber.

The softener can be blended into the copolymer rubber together with fillers, vulcanizing agents, etc., but only the softener can be blended in advance when the copolymer rubber is granulated. The use of such a copolymer rubber containing a softener eliminates variations in the supply of the softener to the twin-screw extruder, and also prevents the softener from adhering to the inner wall of the twin-screw extruder and causing slippage during kneading. This is particularly preferred since it does not cause shortages.

Furthermore, sulfur compounds or organic peroxides are generally used as the vulcanizing agent.

As the sulfur compound, for example, sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, selenium dimethyldithiocarbamate, etc. are used, and the use of sulfur is particularly preferred. These sulfur compounds are used in an amount of about 0.1 to 10 parts by weight, preferably about 0.5 to 5 parts by weight, per 100 parts by weight of the copolymer rubber.

When using a sulfur compound as a vulcanizing agent, it is preferable to use a vulcanization accelerator in combination. u as a vulcanization accelerator, e.g. jr
-N-cyclohexyl-2-benzothiazole-sulfenamide, N-oxydiethylene-2-benzothiazole-sulfenamide F,N.

N-diisopropyl-2-benzothiazolesulfenamide, 2-mercaptobenzothiazole 2-(2,4
-dinitrophenyl)mercaptobenzothiazole, 2
- Thiazole series such as (2,6-danityl-4-morpholinothio)benzothiazole and dibenzothiazyl-disulfide; guanidine series such as nidiphenylguanidine, triphenylguanidine, diorthotolylguanidine, orthotolyl biguanide, and diphenylguanidine phthalate; Aldehyde-amine or aldehyde-ammonia systems such as acetaldehyde-aniline condensation products, butyraldehyde-aniline condensation products, hexamethylenetetramine, acetaldehyde-ammonia; imidacillin systems such as 2-mercaptoimidacillin;
Thiourea series such as thiocarpanilide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetrasulfide, etc. Zinc thiuram 5-dimethyldithiocarbamate,
Dithioate salts such as zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, etc. Xanthate-based substances such as zinc; other examples include zinc carbonate, stearic acid, and zinc stearate. These vulcanization accelerators are used in an amount of about 0.1 to 2 per 100 parts of copolymer rubber.
0 parts by weight, preferably about 0.2 to 10 parts by weight.

Examples of harsh organic substances include dicumyl peroxide,
2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-
Di(tert-butyl≠ruberoxy)hexyne-3, di-tert-butyl peroxide, di-tert-butyl peroxy-3,3,5
-) Limethyl cyclohexane, tert-butyl human tetraperoxide, etc. are used, especially dicumyl peroxide, di-tert-butyl peroxide, di-tert-butyl peroxy-3
, 3,5=trimethylcyclobexane is preferably used.

These organic peroxides are used in an amount of about 0.1 to 10 parts by weight, preferably about 0.5 to 8 parts by weight, per 100 parts by weight of the copolymer rubber.

When using an organic peroxide as a vulcanizing agent, it is preferable to use a vulcanizing aid in combination. Examples of vulcanization aids include sulfur,
Quinone dioxime systems such as p-quinone dioxime, methacrylate systems such as polyethylene glycol dimethacrylate, allyl systems such as diallyl phthalate and triallyl cyanurate, other maleimide systems, and divinylbenzene are used. Such a vulcanization aid is used in a proportion of about 0.5 to 2 moles, preferably about 1 mole, per mole of organic peroxide used.

The above fillers, softeners, and vulcanizing agents are uniformly mixed together with vulcanization accelerators, stabilizers, colorants, etc. as necessary, and then supplied to a twin-screw extruder, where they are continuously mixed with the copolymer rubber. Kneaded separately.

As a twin-screw pushing machine, the commonly used Japan Steel Works O Engineering M99S, Kobe Steel New Auto mi, xer
M2S etc. are used, and Ml jf of the rubber compound is kept at a temperature such that the vulcanizing agent does not perform the vulcanizing action, generally about 10
The kneading operation is performed under conditions such that the residence time is about 0.1 to 1 minute while cooling with water to a temperature of 0 to 130°C. The kneading process performed in this way is
Since it enables continuous operation, it is combined with the subsequent continuous vulcanization process and continuous molding process, making it possible to vulcanize and mold the copolymer rubber in a consistent manner as a whole. The physical properties of the vulcanized rubber of the final vulcanized copolymer rubber molded product are also comparable to those kneaded by the batch method.Therefore, ethylene which can be vulcanized at high temperature and in a short time・α−
The characteristics of olefin/polyene copolymer rubber will be fully exhibited.

Next, the present invention will be explained with reference to examples.

Example 1 Ethylene/propylene/5-ethylidene-2-norbornene copolymer rubber (ethylene/propylene molar ratio 68/3
2. Particulate matter (weight 10 particles per 100 particles) of iodine monovalent 14) was continuously passed through a twin-screw pusher (Japan @ Kosho C-M90s; screw outer diameter 90) using a screw feeder.
+vm, L/D-12).

Each compounding agent listed in Table 1 below was mixed uniformly with a Henschel mixer, then adjusted with a table feeder so that the blending ratio with the copolymer rubber was as shown in Table 1, and this was continuously extruded using the above 2i111 extrusion. I started supplying it to the machine.

Table 1 Particulate copolymer rubber 100 m
lead flower
5 stearic acid l5R
F Carbon Black (Asahi Carbon Products Asahi $50)
75 Heavy calcium carbonate (Shiraishi Calcium Products Whiten SB) 30 Clay (Southern Easton Clay Products Crown Clay) 30 Process oil (Idemitsu Kosan Products pw380) 35 Vulcanization accelerator MBT (Anauchi Shinko Chemical Products Tsukusela M)
0.75tt MBTS (Anauchi Shinko Chemical Products Tsukseller DM) 0.75s TMTD (Anauchi Shinko Chemical Products Tsukseller TT) 0.5i
Oh
1 of the above formulation at 10 per hour.
Adjust the feed rate to 0Kp using a feeder, feed it to a twin screw press with a screw rotation speed of 1100 rpm, cool it with water, and knead it while controlling fW so that the temperature of the compounded rubber is about 100 to 130 °C. A vulcanizable rubber compound (unvulcanized rubber compound) was prepared.

Comparative Example 1 In Example 1, a normal veil type copolymer rubber was used as the copolymer rubber, and the most common patch method mixture w41! !
Henschel mixer (Kobe Steel vJ4.a p
ooa type) and kneaded for 4 minutes to prepare an unvulcanized rubber compound.

Example 2 Particulates (weight 5 g per 100 particles) of ethylene-propylene-dicyclopentadiene copolymer comb (ethylene/propylene molar ratio 65/35, iodine value 15),
Continuous twin-screw pushing machine with screw feeder (Kobe Steel New Auto mixθr M2S i screw outer diameter 6
Each compounding agent listed in Table 2 below was mixed uniformly in a Henschel mixer, and then blended with the copolymer rubber in a table feeder. The ratio was adjusted as shown in Table 2, and the mixture was continuously fed to the twin screw press.

Table 2 Particulate copolymer rubber 100 Heavy F Zinc Flower
5 Stearin City 11 FI'
? Carbon No Tsuku (Asahi Carbon Products Asahi $60)
150 process oil
104 Defoaming agent (Benjo lime product Bester PF)
10 Vulcanization accelerator MBT
O, 4 TL (Kawaguchi Chemical Accel T
L) 0.5tt DPTT (Omukai Shinko Kagaku Tsukusera TRA) o, s// TM
DT 1s M
DB (Omukai Shinko Chemical Products Tsukseller MDB) 1
．． 5 I Ou
0.7 The above compound was adjusted with a feeder so that the feed rate was 60 Kf/hour, fed to a twin screw press with a screw rotation speed of 200 rpm, and cooled with water until the temperature of the compound rubber was about 110 to 130°C. An unvulcanized rubber compound was prepared by kneading and adjusting the mixture so that the following properties were achieved.

Comparative Example 2 In Example 2, a conventional veil-shaped copolymer rubber was used, and the same batch kneading as in Comparative Example 1 was carried out to prepare an unvulcanized rubber compound.

Example 3 In Example 2, 140 parts by weight of particulate copolymer rubber (207 parts by weight per 100 particles) was used, in which 40 parts by weight were previously blended out of 104 parts by weight of softener process oil, and 2 An unvulcanized rubber compound was prepared by kneading with an extruder.

Comparative Example 3 In Example 3, an ordinary veil-shaped copolymer rubber was used, and the same batch kneading as in Comparative Example 1 was carried out to prepare an unvulcanized rubber compound. Regarding the unvulcanized rubber formulations obtained in the comparative example, the Mooney viscosity MTJ, +4 (100°C) and density were evaluated, and these formulations were tested at 160°C.
Regarding the sheet-like body (14 cm x 12 cm x 2 m) obtained by press vulcanization for 30 minutes (Example 1, Comparative Example 1) or 20 minutes (other Examples, Comparative Examples),
The physical properties of the vulcanized rubber were measured. The results obtained are shown in Section 3 below.

Table 3 Example 1 67 1.26 82 153
500 61 Comparative Example 1 69 1.27 8
5 149 480 60 Example 2 72
1.15 84 105 420 67 Comparative example 2 70 1.15 - 110 2
80 67 Example 3 95 1.16 110
155 450 70 Comparative Example 3 90 1
．． 15 105 150 400 70 Representative Patent Attorney Yoshi 1) Toshio

Claims (1)

[Claims] 1. l'f' heptadolar ethylene/α-olefin/polyene copolymer rubber, filler, softener, and vulcanizing agent are directly fed to a twin-screw extruder and continuously kneaded. A method for producing a vulcanizable rubber compound, the method comprising: 2. A method for producing a vulcanizable rubber compound according to claim 1, wherein a particulate copolymer rubber having a weight of about 0.1 to 200 g per 100 particles is used. 3. A method for producing a vulcanizable rubber compound according to claim 1 or 2, wherein a particulate copolymer rubber containing some or all of the softening agent is used.