Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
  • C08L9/02—Copolymers with acrylonitrile
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/14—Peroxides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L15/00—Compositions of rubber derivatives
  • C08L15/005—Hydrogenated nitrile rubber
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/16—Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers

Definitions

• the invention relates to a mixture comprising one or more olefin rubbers and one or more nitrile rubbers, a ner process for their
• Mixtures (blends) of incompatible elastomers are common in technical rubber articles.
• the polymer components are mixed in a mixing cycle together with the usual additives without special measures being taken to improve the phase structure.
• Improved mixing methods provide for more complicated, often multi-stage processes that are time-consuming and result in excessive mixing costs.
• Mixtures of olefin polymers with nitrile rubbers are, for example, from
• EP-A2-0 146 068, EP-A1-0 773 255 and US-A-3,492,370 are known. Even if these appear macroscopically homogeneous, extended domains of disperse phases become clear in phase contrast microscopy (FIG. 1).
• the object of the present invention was to provide a mixture of
• Olefin rubber and nitrile rubber with improved properties.
• the object is achieved by a mixture comprising one or more olefin rubbers and one or more nitrile rubbers, characterized in that there is no phase separation in the mixture.
• olefin rubber means copolymers of ethylene and one or more ⁇ -olefins, terpolymers of ethylene, one or more ⁇ -olefins and one or more non-conjugated dienes, and also mixtures of polymers containing the polymers mentioned.
• the ⁇ -olefins are selected in particular from the group propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-nonen, very particularly propylene, 1-butene, 1-hexene and 1 octene.
• the non-conjugated dienes are selected in particular from the group 1,4-hexadiene, 1,5-heptadiene, 5,7-dimethyl-1, 6-octadiene, 7-methyl-1, 6-octadiene, 4-vinyl l-cyclohexene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene and dicyclopentadiene, especially 1,4-hexadiene, 7-methyl-l, 6-octadiene, 5-ethylidene-2-norbornene, 5- Vinyl-2-norbornene and dicyclopentadiene.
• Suitable olefin rubbers generally have Mooney viscosities (DIN 53 523, ML 1 + 4, 125 ° C) of 20 to 100 ME, in particular 25 to 80 ME, but it is also possible to use liquid olefin rubbers, especially liquid EP (D ) To use M-autschuke.
• the degree of hydrogenation can be determined by NMR and IR spectroscopy.
• Hydrogenated nitrile rubber is characterized by high tear resistance, low abrasion, low deformation after compression and
• Suitable nitrile rubbers generally have Mooney viscosities (DIN 53 523,
• ML 1 + 4, 100 ° C) from 25 to 120 ME, in particular 40 to 100 ME, but it may also be advantageous to use liquid nitrile rubbers.
• phase separation means that the domains of the disperse phases have an average diameter of less than 10 ⁇ m.
• the phases are not spherical structures, but rather irregular structures with constrictions and protuberances (see Fig. 1-3), so that the diameter must be measured at the narrowest point.
• a first assessment is often already possible visually with phase contrast microscopy. So when comparing Figures 1-3, the Difference of the mixtures according to the invention from the prior art is significant (FIG. 1 in comparison to FIGS. 2 and 3).
• the average diameter of the domains of the disperse phases is preferably below 5 ⁇ m.
• Another object of the application is a process for the preparation of a mixture comprising one or more olefin rubbers and one or more nitrile rubbers, characterized in that before or during the preparation of the mixture, small amounts of a crosslinking system which is active at the mixing temperature, in particular a peroxide system with a Decomposition temperature below the mixing temperature.
• any mixing element for rubbers known to the person skilled in the art can be used as the mixing element, in particular kneaders, rollers and screws.
• the Mooney value of the mixture increases during the mixing process.
• the necessary amount of crosslinking agent, in particular peroxide depends on the intended use of the mixture and the desired increase in the Mooney value, but can easily be determined by a few preliminary tests.
• the mixture should not be completely crosslinked.
• the amount of crosslinker required is indirectly proportional to the residual double bond content of the rubber.
• the aim of the mixing process is to produce the mixture in such a way that, when extracted for 10 hours in a Soxhlet attachment, using toluene or a solvent from the group consisting of dichlorobenzene, methyl ethyl ketone or mixtures thereof as extracting agents, more than 90, preferably more than 95,% by weight , based on rubber, is extractable.
• the mixture should therefore not be completely cross-linked.
• Crosslinking in the sense of the invention means that when extracted for 10 hours in a Soxhlet attachment with toluene as the extraction agent, less than 10, preferably less than 5% by weight, based on rubber, can be extracted.
• the crosslinking agent is active at or below the mixing temperature, that is, initiates the crosslinking.
• the decomposition temperature of the peroxide system is below the mixing temperature.
• the following peroxides are suitable, for example, for the process according to the invention:
• the amounts of peroxide are generally in the range from 0.2 to 5 phr, preferably in the range from 0.5 to 3 phr, based on rubber.
• the peroxides can advantageously also be used in polymer-bound form.
• Sulfur can be used as soluble or insoluble sulfur, as a mixture thereof (powdered, coated) or in another suitable form, e.g. B. as a premixed mixture of sulfur and rubber "sulfur batch".
• the dosage is usually in the range of 0.1 to 5 phr, preferably 0.1 to 1.5 phr
• thiuram are generally suitable as sulfur donors, in particular tetramethythiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide and tetrabenzylthuram disulfide. These can in turn be used in combination with other sulfur-containing components, for example dithiomorpholide, dithiocaplolactam or other compounds with a di-, tri-, tetra- or poly-sulfide structure.
• the dosage of the thiuram derivatives is usually in the range from 0.5 to 5 phr, preferably 1 to 2.5 phr.
• Components are generally selected in the range from 0.1 to 3 phr, preferably 0.5 to 1.5 phr.
• Sulfur crosslinking systems can also contain accelerators.
• Mercaptobenzothiazole or accelerators are preferred
• Zinc salts of dithiocarbamic acids in doses in the range from 0.5 to
• Retarders such as phthalic acid, phthalic anhydride, benzoic acid or salicylic acid or other organic acids, such as N-nitroso compounds or such as N-cyclohexylthiophthalimide or other sulfonamide derivatives, such as Vulkalent
• any combination of crosslinking agents and accelerators generally requires activators, preferably zinc oxide and fatty acids.
• the dosage of zinc oxides is usually in the range from 2 to 15 phr, preferably 3 to 5 phr.
• a suitable fatty acid is, for example, stearic acid, which is generally used in doses in the range from 0.1 to 2 phr, preferably 0.3 to 1 phr.
• the mixture generally takes place at temperatures in the range from 150 to 200.degree. C., preferably from 160 to 190.degree. C., optionally under a pressure of 10 to
• the mixtures can be annealed by storage at a higher temperature.
• the mixtures according to the invention can also contain the usual additives.
• Suitable additives are for example those known to those skilled in vulcanization, in particular metal oxides, such as zinc oxide or magnesium oxide, anti-aging agents, such as alkyl-substituted diphenylamine ine, Mercaptobenz- imidazole, unsaturated ethers such as Vulkazon ® AFD (Bayer AG, D) or cyclic, unsaturated acetals, like Vulkazon ® AFS LG (Bayer AG, D) in question.
• plasticizers especially carboxylic acid esters, such as sebacic acid and its derivatives or trimellitic acid and its derivatives
• Processing aids in particular stearic acid and derivatives thereof, such as zinc stearate or polymers, such as poly-ethylene-vinyl acetate (Levapren ® of Bayer AG, D) or poly-ethylene vinyl acrylate / NAMAC ® from DuPont).
• stearic acid and derivatives thereof such as zinc stearate or polymers, such as poly-ethylene-vinyl acetate (Levapren ® of Bayer AG, D) or poly-ethylene vinyl acrylate / NAMAC ® from DuPont).
• fillers into the rubber mixture according to the invention. These can be non-reinforcing or reinforcing.
• fillers are:
• Carbon blacks such as MT, GPF, SRF and especially FEF carbon blacks, metal oxides, such as titanium dioxide (especially as a white pigment), silicates, such as sodium aluminum silicate - silicas, in particular precipitated silicas
• silanes such as Ucarsil ® RC-1 (Union Carbide, US). Pigments can also be added.
• the amounts of the individual components of the mixture depend on the intended use of the mixture and can be determined by a few preliminary tests.
• the additives and fillers are mixed in by mixing processes. It is important to ensure that the mixture is not broken down during the mixing process. It can therefore be advantageous to cool during the mixing process.
• the mixtures prepared in this way can be further mixed with crosslinking agents in order to obtain crosslinkable mixtures which are then finally converted into moldings of all types.
• crosslinkers are usually added whenever there is no need to crosslink with high-energy radiation.
• the crosslinking systems and components already mentioned are suitable here, as are all other crosslinking agents known to those skilled in the art, which are only active above the mixing temperature in the process according to the invention, and explicitly include peroxides with a decomposition temperature above the mixing temperature in the process according to the invention
• peroxides are suitable for example in addition to the peroxides mentioned:
• Peroxide esters e.g. Di-tert-butyl
• the crosslinking system is often added as the last component, possibly in a separate mixing process.
• crosslinkers are sulfur or sulfur donors and combinations of these components already described.
• Mixtures with and without crosslinking agents each result in an at least bimodal elution diagram, which is based on the narrower distribution of the olefin rubber in the range of lower molecular weights and on the broad nitrile rubber distribution in the range of high molecular weight distribution is determined.
• FIGS. 1-3 show the improvement in the phase distribution of the polymer components which can be proven by micro-optical investigations, as shown in FIGS. 1-3.
• Figure 1 shows the phase distribution in a mixture according to the prior art, Figures 2 and 3, the improvement achieved by the inventive method.
• Shaped bodies from conventionally produced mixtures are usually characterized by improved mechanical properties and by better resistance in mineral oils.
• Shaped bodies themselves include both shaped bodies in the classic sense, such as
• adhesion promoters such as dispersions / solutions of halogenated polymers, if appropriate with crosslinking agents / fillers / pigments.
• Residual double bond content IR spectroscopy Mooney viscosity ASTM D 1646 (stated in ME) Volatile constituents (% by weight) ASTM D 1416 Ash content (% by weight) ASTM D 1416 acrylonitrile (ACN) content according to the following specification: (% by weight bound in the polymer)
• the rubber is pyrolyzed in a stream of oxygen on a catalyst at 900 ° C.
• the copper that is not used is used in a copper reduction reactor
• the CO2 contained in a Na2CO3 / NaOH trap and the water contained in a MgClO ⁇ trap are then removed from the analysis gas stream.
• the change in the thermal conductivity of the analysis gas compared to the carrier gas flow is a measure of the nitrogen content of the sample.
• Therban _® * C 3446 70% by weight t Buna ® EP G 3440: 30% by weight Trigonox 29/40: 2% by weight
• the polymeric components are introduced, the peroxide is added after 1 min, and the temperature rises to more than 150 ° C. within a further 2.5 min. After a total mixing time of 3.5 min, the mixture is emptied. The mixture is plastic despite the addition of peroxide.
• the mixture according to the invention shows a significantly higher Mooney viscosity, which speaks for a reaction during the mixing.
• This mixture is produced in a further mixing step in the same mixing unit.
• the mixing conditions are chosen in the usual way, namely:
• This step is demonstrated using the example of the transfer from the GK 1.5 E internal mixer described above to a GK 90 E internal mixer, both with intermeshing rotor geometry.
• Variable motor speeds of initially low speed (20 rpm) and low temperature development are essential to ensure a homogeneous dispersion of the peroxide and then to increase the speed to produce the temperature required for the reaction.
• Fig. 4 Schematic course of the mixture production in the internal mixer GK 90 E
• the melt temperature remains in the low revolution range below 120 ° C. Under these conditions, the peroxide practically does not decompose within the residence time, but is only dispersed. As soon as it is set to 70 rpm, the temperatures of approximately 190 ° C. required for the coupling reaction are reached within the following 4 minutes.
• the peroxide dosage suitable here was determined from the following preliminary tests and in the present case set at 1 phr, since 80-90 ME can still be expected to be easy to process (Table 4): Table 4

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)

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• 2000
  • 2000-08-22 DE DE10041235A patent/DE10041235A1/de not_active Withdrawn
• 2001
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