DD285100A5 - MEANS FOR THE THERMAL VOLULATION OF RUBBER MIXTURES - Google Patents

Abstract

The invention describes an agent for the thermal vulcanization of rubber mixtures in the temperature range of 130C to 250C for the production of highly dynamic resilient rubber products, such. As car tires, rubber springs, rubber coupling elements u. ae. The addition of a dispersant adduct consisting of an adsorptive carrier material zeolite and / or layered silicate and an adsorbed surface-active substance (eg surfactant or emulsifier) influences the specific properties of the rubber mixtures in the production, processing and vulcanization process in such a way the production of the above Rubber products is possible. Furthermore, the dispersant adduct improves the economy of the production process. {Zeolite; Layer silicate; surfactant; emulsifier; thermal vulcanization; dynamically heavy-duty rubber products; Dispersant adduct}

Description

OZ 3258

Means for thermal vulcanization of rubber compounds

Field of application of the invention

The invention relates to a means for the thermal vulcanization of rubber mixtures in the rubber industry for the production of rubber products with high dynamic load utility properties such. B. vehicle tires, rubber spring and rubber couplers and other special rubber products

Characteristic of the known state of the art

The use of oberflächenafrbiven substances, such as _f, surfactants, emulsifiers, and soaps, products for the production of plastic, plastic and rubber with certain specific utility properties known.

Thus, an extensive field of application is the use of surfactants as antistatic agents (D. Erwied "Antistatic agents for plastics" in rubber 74 ^ 9847, 10; HW Fink in plastics 64 ^ T9747i 64i W · Biedermann in plastic and rubber 16 £} <&% % 8i OH-PS 554 483) ·

Plastics with antistatic properties prevent electrical charging and they are therefore primarily for the production of packaging materials in microelectronics, floor coverings, records u. a. well suited (DD-PS 256 142) DD-PS 256 143i DD-PS 256 144).

The use of surface-active substances for the polymerization of monomeric organic compounds from aqueous media for the production of certain plastics is also described

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Polyvinyl chloride (I ³ VD), polyvinyl copolymers, styrene acrylonitrile copolymers (SAN), styrene-methyl methacrylate copolymers (SMMA) and the like. DE-OS 2 429 326, DE-OS 2 633 833, DD-PS 246 304i DD-PS 246 305).

In this case, the surface-active substance before the polymerization but also after the polymerization, for example in the processing of the polymer in the calender, are added (DE-OS 3 012 822) _o These technical ancestors, the transparency, the yellowness and the antistatic properties of the polymers improved "

In the OH-PS 577 013 and AT-PS 336 910 the vulcanizable Ileoprenkautschukmischungen surface-active substances in combination with other substances, such as. Magnesium oxide, pentaerythritol and metal soaps, to provide improved Mooney Scorch protection (t / jQ time) and improved processing and storage safety of the unvulcanized neoprene in processing the neoprene rubber blends Vulkanistion be applied by neoprene and they are not transferable to other vulcanization systems. By incorporation of surface-active substances in Piastund Elastmischungen finished products can be produced with hydrophilic character (DD-PS 25I 887) · The products are due to their stain-resistant properties a priority for conveyor belts with dirt-repellent cover plates in the opencast lignite industry and other industries, where In this technical process, the surfactant additives in the rubber mixtures have a positive effect on the contact angle, the surface tension and the distribution of the mixture components. The disadvantage of this process, however, is a decrease in scorch time due to the surfactant additives, which can only be achieved by means of a suitable process Use of an accelerator can be compensated in conjunction with a Vulkanisationsverzögerer. Furthermore, due to the consistency of the surfactants (liquid or pasty), this method leads to an upper dosage of the surfactants and a larger technical

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Effort to homogenize the plastic or Elastmischungen and thus to a deterioration of the economy by increasing the cost.

Object of the invention

The object of the invention is the development of a rubber vulcanization thermal curing agent which aims at improving the technology in the preparation and processing of the rubber compounds, in the vulcanization behavior of the rubber compounds and in the specific utility properties of the rubber products.

Explanation of the essence of the invention

The object of the invention is to develop a means for the thermal vulcanization of rubber mixtures in the temperature range between 150 ⁰ C to 250 ⁰ C, which improves the specific properties of the rubber mixtures and rubber products. Particularly important here is the improvement of the cold compatibility of the mixture ingredients in the Polymermat.vix, the fillability of the polymer matrix with fillers or polymers, the flow behavior and the vulcanization behavior of rubber compounds and the specific utility properties of the rubber products · The task was solved by the filler-containing rubber mixtures Base of natural and / or synthetic elastomers and / or plastomers with the usual Mischingingredienzien a homogeneous dispersant adduct in the concentration range of 1 to 25 % _t preferably 2 to 1O %, based on the total mass of the rubber mixture, in a single-stage mixing process of the mixture is added the homogeneous dispersant adduct is understood to mean a rubber compounding ingredient consisting of an adsorptive carrier material zeolite and / or layered silicate and an adsorbed surface-active substance, such as e.g. As surfactant or emulsifier, according to the invention in the following limits:

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2851OO

Zeolite and / or phyllosilicate 95 to 50 %

Surfactant and / or emulsifier 5 to 50 %

The adsorptive carrier material consists of synthetic powdery and anhydrous zeolites of the A, X and Y types and / or a layered silicate of the magadiite type. As adsorbed surfactants and / or emulsifiers anionic, nonionic, cationic and ampholytic substances can be used. The low-priced surfactants alkyl sulfate, alkylbenzene sulfonate and alkylphenol ethoxylate have proven particularly useful. Surprisingly, when using the composition according to the invention, it was found that effects were achieved by the synergistic activity of the dispersant adduct, resulting in an improvement in the technological production of the rubber mixtures, in the processing and vulcanization behavior of the rubber mixtures and in the physical-mechanical property profile and in the aging behavior of the rubber Rubber products showed. At the same time, these positive effects have been associated with a reduction in substances, greater manufacturing efficiency, saving time, cost and energy, improved storage stability and processing safety.

In the preparation of the rubber compounds, a faster and better dispersion and homogenization of the mixture ingredients was achieved. This ensured a higher stability of the homogeneous distribution and a reduced segregation and migration of the mixture ingredients.

This improved cold compatibility of the blend components allows a higher degree of filling of the polymer matrix with fillers or with polymers that are difficult to combine under normal conditions. Through this extended variation and blend options by fillers or polymers, the specific property picture of a rubber product can be specifically improved, such. B. the improvement of the cold behavior based on natural rubber for the production of dynamically heavy-duty rubber element products (eg, springs, couplings) by a

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2 8 5 ί Ο Ο

increase in the percentage of 1,4-iso-polybutadiene in the natural rubber polymer matrix. ·

In the manufacturing, extraction and molding process, the wall adhesion problems in the processing machines are reduced. By lowering the elastic component in the visco-elastic system of the polymer blends, the elastic recovery (injection swelling) is reduced, which makes it possible to process high-carbohydrate-containing mixtures on the extruder. In the vulcanization process can be dispensed with the use of an amine secondary accelerator. As a result, the Vulkanisa, tion behavior of such rubber mixtures manageable. The improved cold compatibility of the blend ingredients reduces stress corrosion, improves surface strength and increases the dynamic and static ozone resistance of the rubber products.

The following example is intended to illustrate the agent according to the invention without limiting it.

embodiment

The rubber clogs were produced in a laboratory internal mixer type GK 4N and on a rolling mill according to a uniform mixing procedure.

The processing behavior of the rubber compounds was tested and evaluated as a function of the shear rate by means of an MPT measuring device (Monsanto Processability Tester). The rheological-vulcanic behavior of the rubber mixtures was determined by taking up cross-linking isotherms on the rheometer and the physical-mechanical characteristics of the vulcanizates were tested and evaluated according to valid TGL regulations.

test formulation

mix version A B C D 100.0 100.0 e F G H Concentration: Mass fractions in ingredients 100.0 100.0 42.5 42.5 100.0 100.0 100.0 100.0 1,4-poly-iso- 42.5 42.5 butadiene 46.5 46.5 - - 25.0 25.0 25.0 25.0 polyisoprene 46.5 46.5 - - 25.0 25.0 2 ', 0 25.0 FEF carbon black - - 1.5 1.5 38.0 38.0 30.0 30.0 paraffinic softener - - 3.0 3.0 5.0 5.0 5.0 5.0 stearic acid 1.5 1.5 1.0 1.0 1.5 1.5 1.5 1.5 zinc oxide 3.0 3.0 1.5 1.5 3.0 3.0 3.0 3.0 2-Merkap t obenz o- thiazole 1.0 1.0 1.0 1.0 1.0 1.0 sulfur 1.5 1.5 mm 1.5 1.5 1.5 1.5 Alkylbenzen- Ii / * I. A sulfonate 4.0 8.0 - mm 4.0 "· MM MS 4A / alkylbenzene zensulfonat adduct - - - - 8.0 - (50 ϊ 50) - 8.0 MS 4A / alkylphenol ethoxylate adduct - - - - - 8.0 (70: 30) test results:

Table 1: Determination of the energy consumption during the mixing process with constant mixing time (6 min ₀ ) corresponds to cold compatibility

Mixture variant Energy intake ^ L 7 Percentage in %

A 36 173 100.0

B 32 161 88.9

0 24 869 68.8

D 24 492 67.7

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e 47 465 P 40 273 G 28 123 H 27 572

100.0 84.8 59.2 58.1

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Table 2: Determination of the processing characteristics of the rubber compounds in the MPT tester as a function of the shear rate

Conditions: Dü3e - 2i temperature; 100 250 C kPaoS mn ⁰ C a MPa 500 C kPa.S a MPa 750 C kPa.S a MPa 1000 C kPa.S Shear rate / cm / sec7 b MPa 1.51 27.53 b MPa 0.86 29.65 b MPa 0.61 31.03 b MPa 0.48 characteristics a MPa 0.38 1.34 d 25.65 0.43 0.78 27.24 0.46 0.59 29.51 0.49 0.47. A 24.13 0.34 1.07 28 21.93 0.42 0.67 22,75 0.44 0.56 23.86 0.46 0.44 B 21.93 0.27 1.02 26 21.37 0.38 0.63 22.41 0.40 0.54 23.44 0.41 0.43. C 17.10 0.25 2.82 21 30.89 0.38 1.42. 31.85 0.40 1.08 32.75 0.41 0.62 D 16.20 0.43 2.41 20 28.61 0.47 1.18 28.41 0.48 0.87 30.13 0.49 0.54 e 29.30 0.39 1.34 16 22.41 0.44 0.72 23.31 0.44 0.59 23,79 0.46 0.43 25.37 0.28 1.12 15 22.06 0.39 0.69 22,75 C, 41 0.56 23.99 0.41 0.44 G 19,03 0.27 13 In the table mean: 0.39 0.40 0.41 e 13.06 12 Annotation :

a = injection pressure, ΐ> = shear stress, c = viscosity, d = injection swelling

Table 3:

Determining the rheologically-vulkametrischen characteristics of the rubber compounds at T = 150 ⁰ C.

characteristics

^M L

EE EE

t ₂ time min,

₉ min,

₉ Minute

mix 8 42 5.2 12.5 7, 3 34 I50 6 H ⁰ o variant 7 44 4.9 12.1 7, 2 37 Vulcanization time * 15 Sh Minute A 6 48 4.7 11.2 6 5 42 Specimen; B 6 52 4.6 10.8 6 2 46 ^M 300 ^{Γ D} C 16 68 6.4 14.2 7, 8th 52 MPa MPa % D 14 72 5.8 12.4 6 6 58 e 12 73 5.3 11.3 6 0 63 F 12 78 5.2 10.8 5, 6 66 G (tg _O -t ₂ ) = characteristic value as an expression : For vulcanization mm test flaps H speed W Annotation; (Mjjg-M ^) ^xx = characteristic value as expression for the networking K / mm Degree Determination of physico-mechanical characteristics the vulcanizates Table 4: Temperature: Conditions: Ke.cnwerte

Mixture variant A

4.9 5.3 6.1 6.4

8.1

9.1 9.4

38 38 40 43

9.7 11.4 12.1

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e 9.8 11.4 475 58 14.5 F 10.9 12.1 434 .60 17.3 G 13.3 14.1 368 63 21.3 H 13.7 14.4 65 21.8

As a result of the composition according to the invention, the specific properties of the rubber mixtures and their vulcanizates (variants O, D, G, H) were markedly improved compared to the procedure not according to the invention (variants Δ, B, E, F). This was reflected in a significant improvement in KalOvorträglichkeit of the mixture components in the preparation of rubber mixtures and in an associated increase in the fluidity of the rubber mixtures in the processing process such _o B ₀ viscosity, injection pressure, Spritzciuellung and shear stress · Furthermore the Dispergiennittel adduct caused in the vulcanisation the rubber blends an increase of the vulcanization rate and the Vemetsungsdichte. This has been important specific

Characteristics of the vulcanizates of such _e B ₀ Spanniingswerte, vulcanisate hardness, tensile strength and tear resistance, improved significantly.

Claims (5)

claims * Means for the thermal vulcanization of rubber mixtures based on natural and / or synthetic elastomers and / or plastomers with the usual Mischingingredienzien in the temperature range between 130 ⁰ O to 250 ⁰ C, characterized in that a homogeneous Dispergiennittel adduct consisting of an adsorptive carrier substance Zeolite and / or layered silicate and an adsorbed surface-active substance is added, with a concentration of 1 to 25 % based on the total mass of the rubber mixture, in a one-stage process of the mixture. 2. Composition according to claim 1, characterized in that the dispersant adduct is added in a concentration of 2 to 10 % based on the total mass of the rubber mixture of the mixture. .3 Composition according to Claims 1 and 2, characterized in that the adsorptive carrier substances are synthetic, anhydrous and pulverulent zeolites of the A, X and Y type and / or layered silicates of the magadiite type. 4. Composition according to claims 1 and 3, characterized in that the surface-active substances are anionic, nonionic, cationic and ampholytic surfactants and / or emulsifiers. 5. Composition according to Claims 1 to 4, characterized in that the composition of the homogeneous dispersant adduct lies within the following limits: Zeolite and / or Phyllosilicates, t 95 to 50 % Surfactant and / or Emulsifier 5 to 50 %