WO2006010764A1 - Procede de fabrication d'une charge oxydique traitee en surface - Google Patents

Procede de fabrication d'une charge oxydique traitee en surface Download PDF

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Publication number
WO2006010764A1
WO2006010764A1 PCT/EP2005/053659 EP2005053659W WO2006010764A1 WO 2006010764 A1 WO2006010764 A1 WO 2006010764A1 EP 2005053659 W EP2005053659 W EP 2005053659W WO 2006010764 A1 WO2006010764 A1 WO 2006010764A1
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groups
filler
weight
compositions
reactive
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PCT/EP2005/053659
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German (de)
English (en)
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Harald Ehret
Wilhelm Weber
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Ge Bayer Silicones Gmbh & Co. Kg
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Publication of WO2006010764A1 publication Critical patent/WO2006010764A1/fr

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    • 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
    • C08K9/00—Use of pretreated ingredients
    • C08K9/04—Ingredients treated with organic substances
    • C08K9/06—Ingredients treated with organic substances with silicon-containing compounds
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/20—Protective coatings for natural or artificial teeth, e.g. sealings, dye coatings or varnish
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/90—Compositions for taking dental impressions
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
    • C08L83/04—Polysiloxanes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
    • C08G77/16—Polysiloxanes containing silicon bound to oxygen-containing groups to hydroxyl groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups

Definitions

  • the present invention relates to a process for the preparation of a modified, in particular surface-modified, oxidic filler, the filler enthal ⁇ tend compositions and their use. It also relates to storage-stable polysiloxane compositions which after vulcanization give permanently water-wettable elastomers and their use as dental impression materials or pressure pads.
  • Molding compounds often consist of a binder or polymer and a filler.
  • silicone rubbers when they are used for the molding of objects such as teeth, consist of a polydimethylsiloxane and a finely divided silica.
  • Silicas cause a disperse phase in high or low viscosity liquid polymer phases such as a polydimethylsiloxane both a thickening and a higher rubber mechanical strength when they are cured by cross-linking to an elastomer.
  • the thickening causes an increased viscosity level at low to medium shear rate D of 0.001 to 10 s -1 .
  • oxidic fillers such as silica, a certain structural viscosity is almost always observed, ie a change in viscosity with the shear rate gradient or even a yield value does not have the pure polymer of this size.
  • the thickening influence of e.g. Silica increases when polar polymers such as polyethers are present. These are used in particular for the modification, in particular for the hydrophilization of the surfaces of polysiloxane compositions.
  • WO 98/58997 or US Pat. No. 4,785,047 attempt to overcome the above-described problem by the use of a silica which is obtained by a so-called ' in situ ' treatment, in which the silica initially in the presence is mixed by silazanes and water in polyorganosiloxanes and nachträg ⁇ Lich with further hexamethyldisilazane is brought into contact.
  • a silica which is obtained by a so-called ' in situ ' treatment, in which the silica initially in the presence is mixed by silazanes and water in polyorganosiloxanes and nachträg ⁇ Lich with further hexamethyldisilazane is brought into contact.
  • the silicas used still lead to a pronounced thickening of the uncured polymer compositions.
  • WO 00/61074 uses a silicic acid for producing a composition which is used for the production of hydrophilic duplicating compositions.
  • the silicas treated by the process described therein do not provide for the intermediate removal of water and other low-boiling constituents.
  • the use of these silicas also leads in the presence of small amounts of surfactants, in particular of polyethers, in the polymer composition to a strong thickening, which makes their processing difficult.
  • the inventors have now surprisingly found it possible to provide a process by means of which oxidic filler can be obtained which does not impair the flowability of uncured polymer compositions and at the same time does not lead to deterioration of the (rubber) mechanical properties in the cured polymer composition.
  • the inventors also found that it using this special filler, it is also possible to produce, in particular, polymer-containing polymer compositions which have a low viscosity and intrinsic viscosity, in spite of the effect of the polyethers which reinforces the thickening effect of the silica.
  • compositions with which silicone rubbers can be prepared which, after crosslinking, have a persistently long hydrophilicity and which can be used, for example, as impression compounds for dental impressions.
  • silicic acid is hydrophobized according to a cited prior art in a single step with the addition of hexamethyldisilazane twice. The addition occurs before and during the incorporation of the silica into the polymer. The addition of water is optional.
  • WO 98/58997 discloses a process in which in the first step an amount of more than 1 to 3 wt .-% and - A -
  • an amount of from 10 to 15% by weight of treatment agent per silicic acid is used.
  • the effectiveness of the second step can be markedly increased by the intermediate separation of the low-boiling components after the first hydrophobic treatment, especially if the quantities of surface treatment agent used are kept within certain limits and if water is used in the following stage or step is not added to the steps of re-adding a hydrophobing agent.
  • novel polymer-filler mixtures according to the invention are particularly suitable for producing highly flowable, self-leveling, hydrophilic or antistatic silicone rubbers which are eg can be used as addition-crosslinkable Silikonkaut ⁇ schuke for Dentalabformassen or ink stamp in Päd Printing process advantageous.
  • the systems mentioned here are only permanently hydrophilic to a limited extent since the surface-active compounds partly separate from the polydiorganosiloxane, migrate on the surface thereof or are extracted by the poor bond to the polyorganosiloxane in contact with aqueous media.
  • the water wettability is then, for example, by rinsing with water, decorating during disinfecting, producing duplicates with the aid of water-containing impression materials, such as gypsum lost before the desired impression with reproducible wetting properties of the silicone mold is achieved after demolding from the moist replicate surface.
  • alkylene ether copolymers are known as anti-fogging agents or hydrophilic silicone rubbers which, by using siloxane-soluble polyethers or reactive polyethersiloxanes which bind to siloxane by hydrosilylation reaction contain.
  • These reactive polyethersiloxanes contain e.g. Vinyl groups or optionally Si-H groups.
  • EP-A-231 420 discloses silicone impression compositions in which the attachment of polyether units to a component of the polyorganosiloxane is suggested to obtain permanently water-wettable vulcanizates.
  • this composition and those of DE 1 519 412 the production-related content of hydrosilylation catalyst still present in the polyethers limits any use in reactive polysiloxane rubbers with a minimum storage time of several days.
  • EP-A-398 745 and EP-A-429 069 disclose silicone rubber compositions using polyether radicals bonded to siloxanes.
  • EP 602 128 solves the problem of storage stability of hydrophilic silicone rubbers with chemically bound polyether part by the use of a noble metal-free polyethersiloxane, according to the aforementioned proposals.
  • the present invention therefore provides a process for the preparation of an oxidic filler comprising the steps:
  • Step a) involves mixing at least one reactive silane i) with at least one oxidic filler, if appropriate in the presence of water.
  • Step a) is useful in a temperature range of about room temperature (25 0 C) to about 200 0 C and about normal pressure (1013 mbar) to about 30 bar.
  • the mixing is carried out at room temperature and atmospheric pressure.
  • the mixing is carried out in a conventional mixing apparatus, such as kneaders, dissolvers, mixing turbines, screw mixers, extruders, stirred tanks, preferably in a kneader or dissolver.
  • the mixing time ranges, for example, from about 10 minutes to about 400 minutes.
  • Step a) is carried out in the presence of water when the reactive silane i) is selected from organosilazanes, hexaorganodisilazanes, trialkylsilylamines, trialkylsilyloximes, trialkylsilylamides or organoalkoxysilanes.
  • water serves as a reaction partner for the formation of hydroxy-functional intermediates of said reactive silanes.
  • organosilanols are used as reactive silanes i)
  • the addition of water may be omitted, but this does not preclude the addition of water.
  • water can also serve as a liquid continuous phase in step a) in which the reactive silane i), the oxidic filler, the abovementioned intermediates and cleavage products from the reaction of water and reactive silanes i) are dispersed or dissolved.
  • the liquid continuous phase may also be formed by other solvents, such as inorganic or organic solvents, low or high viscosity polymers. That is to say that the polymers whose reinforcement is intended to be the filler can already be present during the modification of the filler, or in other words that the modification of the filler in the presence of the polymers or the curing composition to be reinforced, for example in the presence component a) of a curable polyorganosiloxane composition described below can take place.
  • the amount of water used in step a) must be at least such that the said reactive silanes i) can be hydrolyzed. Expediently, sufficient water is added to the mixture in step a) so that the reaction products of the reaction of the reactive silane i) with the water can still remain in the aqueous phase or can be sufficiently diluted.
  • the amount of water is at least about 5 parts by weight of water per 100 parts by weight of the silane i), preferably the amount of water used is about 10 to 50 parts by weight per 100 parts by weight of the reactive silane i).
  • the amount of water used is preferably at least about 300 parts by weight per 100 parts by weight of the oxidic filler.
  • the amount thereof is preferably at least about 150 parts by weight per 100 parts by weight of the oxidic filler.
  • the water used in step a) may be separately added water and / or water introduced with the filler.
  • Step a) of mixing the reactive silane i) with the oxidic filler can optionally also be carried out in the presence of a catalyst.
  • the presence of a catalyst is preferably carried out when organoalkoxysilanes or organosilanols are used as reactive silanes i).
  • the catalysts include spielmud: Weak bases and acids with pK a values between 4 to 9. Examples include: ammonia, alkylamines, carboxylic acids, bicarbonates, Hydrogenphospate, hydrogen sulfates, acidic salts of carboxylic acids, Kohlenklare ⁇ semester, etc.
  • the catalyst is suitably used in amounts of 0.5 to 20 wt .-% based on the amount of the reactive silane i).
  • the amounts of the reactive silane i) and of the oxidic filler used in step a) depend inter alia on its type, for example on the specific surface of the filler. In order to achieve a sufficient modification of the filler in step a), it is expedient to use at least about 3 parts by weight of the reactive silane i) per 100 parts by weight of the oxidic filler. An amount of less than 3 parts by weight of the reactive silane i) per 100 parts by weight of the oxidic filler is generally less preferred, since it must be expected that the surface modification is too small.
  • the reactive silane i) is preferably used in an amount of at most about 30 parts by weight of the reactive silane i) per 100 parts by weight of the oxidic filler.
  • the fillers can only absorb a certain amount of the reactive silane i), and the specific surface of the oxidic fillers currently available on the market leads to a restriction of the silane that can be bound to the surface.
  • a preferred amount range of the reactive silane i) used is about 8 to 15 parts by weight of the reactive silane i) per 100 parts by weight of the oxidic filler.
  • the reactive silane i) used in step a) is a silane which is capable of forming, if appropriate by reaction with water, suitable reactive intermediates capable of reacting with the surface of an oxidic filler.
  • such reactive silanes i) are selected from the group consisting of organosilazanes, hexaorganodisilazanes, organosilanols, trialkylsilylamines, trialkylsiloximes, trialkylsilylamides or organoalkoxysilanes.
  • the reactive silanes i) are selected from hexaorganodisilazanes and organosilanols. Particularly preferred are hexamethyldisilazane, 1, 3-divinyltetra methyldisilazane, trimethylsilanol and vinyldimethysilanol.
  • the oxidic filler used in step a) may be any metal oxide. It is expedient to choose from silicic acids, aluminum oxides, aluminum hydroxides, titanium oxides which are prepared by various processes, such as flame hydrolysis, precipitation processes, etc.
  • the BET specific surface area of the oxidic fillers is preferably at least about 20 m 2 / g, more preferably at least about 40 m 2 / g, more preferably at least about 100 m 2 / g, even more preferably at least about 130 m 2 / g. Examples include fumed silicas such as Aerosil (Degussa), HDK (Wacker), Cab-O-Sil (Cabot).
  • a preferred filler which is treated according to the invention is silica, preferably having a BET specific surface area of at least about 130 m 2 / g.
  • Step b) comprises separating low-boiling constituents from the mixture obtained in step a) by adjusting such pressure and temperature conditions that the low-boiling constituents contained in the mixture evaporate.
  • Such low-boiling constituents are, in particular, constituents having a boiling point of less than 180 ° C. under atmospheric pressure (1013 mbar), such as water, ammonia, alcohols, amines, hydroxylamines, amides and silanols which have formed in step a).
  • Suitable pressure and temperature conditions are for example temperatures of 30 to 250 0 C and pressures of about 0.01 to 1013 mbar.
  • step b) Temperatures of more than 25O 0 C are less preferred in step b), since it can lead to decomposition of the liquid continuous phase, in particular when it comes to liquid polymers. Moreover, such a high temperature is less desirable from an economic and ecological point of view.
  • the evaporation of the low-boiling constituents takes place at a temperature of 120 to 180 ° C and vacuum (10- 50 mbar).
  • Step b) expediently takes place in the mixing apparatus mentioned in step a) with stirring or kneading.
  • Step b) is expediently carried out until the proportion of low-boiling components of the mixture has been reduced to less than 10% by weight, more preferably less than 5% by weight, even more preferably less than 0.5% by weight .
  • the proportion of low-boiling constituents in the mixture obtained in step b) is advantageously determined by keeping the mixture at a temperature of 15O 0 C / 20 mbar for 45 minutes and determining the resulting weight loss (initial weight - final weight) according to the formula:
  • Percentage of low boiling components in weight percent (weight loss / original weight) x 100.
  • Step c) of the process according to the invention involves the addition of at least one reactive silane ii), without the addition of water and optionally the
  • step b) Heating the resulting mixture.
  • the addition of the reactive silane ii) after the Separation of the low-boiling constituents in step b) is expediently carried out after adjustment of such pressure and temperature conditions under which the contact time between the reactive silane ii) and the pretreated oxidic filler permits adequate reaction of the two components.
  • the admixing of the reactive silane (ii) can be carried out, for example, at a temperature of from room temperature to 150 ° C., preferably under atmospheric pressure. The addition preferably takes place at room temperature.
  • the temperature may optionally be increased as long as one of the silanes remains in the mixture for a certain time or remains in contact with the pretreated oxidic filler.
  • the contact time after addition should expediently be at least about 30 minutes.
  • the contact time depends on the contact temperature, the reactivity of the silanes ii) and their concentration in the mixture.
  • the contact time may preferably be up to 2 days, in particular if the contact takes place at room temperature.
  • the conditions of this further separation step can essentially correspond to the conditions of step b). If appropriate, steps b) and c) can be repeated once or several times.
  • the reactive silanes ii) of step c) may be the same or different than the reactive silanes used in step a). Preference is given in
  • Step c) uses the same reactive silanes as in step a).
  • the reactive Silanes ii) of step c) are preferably selected from the group consisting of organosilazanes, hexaorganodisilazanes, trialkylsilylamines, trialkylsilyloximes or trialkylsilylamides. More preferably, the reactive silanes ii) are selected from hexaorganodisilazanes. Particularly preferred are hexamethyldisilazane and 1,3-divinyltetramethyldisilazane.
  • the amount of reactive silane ii) used in step c) is generally lower than the amount of reactive silane i) used in step a).
  • the amount of reactive silane ii) used in step c) depends, for example, on the amount of reactive silane i) used in step a). In principle, the smaller the amount of the reactive silane i) used in step a), the greater must be the amount of the reactive silane ii) used in step c).
  • less than about 15 parts by weight of the reactive silane ii) is suitably used per 100 parts by weight of the oxidic filler, more preferably less than about 3 parts by weight of the reactive silane ii).
  • An amount less than 0.1 parts by weight of the reactive silane ii) per 100 parts by weight of the oxide filler is generally less preferred because the amount can not sufficiently reliably interact with the surface of the oxide filler.
  • Step c) is carried out without the addition of water.
  • the addition of water, as carried out in step a), in step c) surprisingly results in insufficient reduction of the intrinsic viscosity in the composition with the polymers.
  • oxidic fillers are produced, which cause less thickening than the hydrohob striv according to the previous methods of the prior art fillers effect at the same starting surface.
  • the use of large amounts of reactive silanes in a single-stage modification process does not lead to such a thickening behavior or degree of surface modification, as according to the invention two- or multi-stage modification process is achieved.
  • the surface of the oxidic filler becomes accessible for complete reaction with the reactive silane only by the intermediate separation of the low-boiling components in step b), or that this reaction takes place because of suitable conditions.
  • the thickening effect occurring with the aid of polyethers was chosen as the benchmark for the completeness of the modification.
  • the invention thus relates not only to the fillers prepared by the process according to the invention, but also to compositions which comprise the filler according to the invention and at least one polymer or a crosslinkable composition.
  • Preferred polymers or crosslinkable compositions into which the fillers prepared according to the invention can be incorporated include, for example, reactive resins such as epoxies, polyesters and coating compositions, and in particular polyorganosiloxanes.
  • the filler according to the invention for preparing the composition according to the invention in at least one polymer or in a curable composition or at least a single component thereof in the usual manner with conventional mixing equipment is incorporated, such as kneader , Dissolvers, mixers, such as screw mixers.
  • modified filler produced according to the invention can be used in silicone rubber compositions, a preferred composition using the modified oxidic filler containing the following constituents:
  • At least one hydrosilylation-promoting catalyst selected from the group of compounds or metals containing at least one element selected from Pt, Ru, Rh, Ni, Ir, Ru and Pd,
  • (F) optionally one or more surfactants or other excipients.
  • silicone rubber compositions having the alkenyl group-containing polyorganosiloxane (A) preferably has a viscosity range from 0.025 to 500 Pa.s, preferably from 0.1 to 200 Pa.s (25 0 C; Schergeschwin- dtechniksge hope D of 1 s "1). It may consist of a uniform polymer or mixtures of different polyorganosiloxanes, such as different polymers (A1) or mixtures of the substantially linear polymers (A1) and linear or branched polymers (A2), as described in more detail below, consist.
  • the polyorganosiloxanes (A) can in principle be selected from two groups (A1) and (A2).
  • the group (A1) represents the group of polyorganosiloxanes having a low alkenyl group content of about 0.002 to about 3.0 mmol / g, more preferably between 0.004 to 1.5 mmol / g. These polyorganosiloxanes are generally substantially linear ,
  • Group (A2) represents the group of polyorganosiloxanes having a high alkenyl group content of about 3.0 to about 22 mmol / g. These may include both linear and branched polyorganosiloxanes.
  • the polyorganosiloxanes (A) are preferably prepared by catalytic equilibration or catalyzed polycondensation, as described in US Pat. No. 6,387,487, column 3 u. 4 discloses.
  • the polyorganosiloxanes (A) can be described by the general formula (I):
  • R an optionally substituted organic group, preferably unsubstituted or substituted saturated hydrocarbon radicals, more preferably n-, iso-, tert- or C r C 2 alkyl, (2 Ci-Ci) alkyl Ci-C 2 alkoxy, C 5 - C 30 -cycloalkyl or C 6 -C 3 o-aryl, CrCl 2 - alkyl (C 6 -Cio) aryl, where these radicals R can optionally be substituted in each case by one or more F atoms and / or one or more -O Groups may contain.
  • Suitable monovalent hydrocarbon radicals R include alkyl groups, preferably CH 3 , CH 3 CH 2 , (CH 3 ) 2 CH, CsHi 7 and CioH 2 i groups, cycloaliphatic groups, such as cyclohexylethyl, aryl groups, such as phenyl, ToIyI, XyIyI, aralkyl groups such as benzyl and 2-phenylethyl groups.
  • Preferred monovalent halohydrocarbon radicals R have in particular the formula C n F 2n + iCH 2 CH 2 - where n has a value of 1 to 10, such as, for example, CF 3 CH 2 CH 2 -, C 4 FgCH 2 CH 2 - and C 6 Fi 3 CH 2 CH 2 -.
  • a preferred radical is the 3,3,3-trifluoropropyl group.
  • Particularly preferred radicals R include methyl, phenyl and 3,3,3-trifluoropropyl.
  • R 1 R or an unsubstituted or substituted C 2 -C 2 -alkenyl, which are preferably selected with the proviso that at least two radicals R 1 are an alkenyl-containing organic group consisting of: unsubstituted and substituted alkenyl-containing hydrocarbon radicals, such as n-, iso -, tert - or cyclic C 2 -C 2 alkenyl, vinyl, allyl, hexenyl, C 6 -C 30 -cycloalkenyl, cycloalkenylalkyl, norbornenylethyl, limonenyl, C 8 -C 3 o-alkenylaryl, wherein optionally one or several - O atoms may be present (corresponding to ether residues) and which may be substituted by one or more F atoms.
  • R 1 R or an unsubstituted or substituted C 2 -C 2 -alkenyl, which are preferably selected with
  • Preferred radicals R 1 are groups such as vinyl, allyl, 5-hexenyl, cyclohexenylethyl, limonenyl, norbomenylethyl, ethylidene norbornyl and styryl, particularly preferably vinyl.
  • R 2 a divalent aliphatic n-, iso-, tert- or cyclic d-Ci 4 alkylene radical, or a C ⁇ -Cu-arylene or Alkylenarylrest is, in each case two siloxy units M, D or T bridged, R 2 , as defined in formula (I), bridges two siloxy units M, D or T.
  • the divalent units R 2 bridge two siloxane units, for example -DR 2 -D-.
  • R 2 is preferably selected from divalent aliphatic or aromatic n-, iso-, tert- or cyclic C 1 -C 14 -alkylene, C 6 -C 4 -arylene or -Alkylenaryl phenomenon.
  • Suitable divalent hydrocarbon groups R 2 which can bridge siloxy units include all alkylene and dialkylarylene radicals, preferably those such as -CH 2 -, -CH 2 CH 2 -, CH 2 (CH 3 ) CH-, - (CH 2 ) 4 , -CH 2 CH (CH 3 ) CH 2 -, - (CH 2 ) 6 - - (CH 2 ) 8 - and - (CH 2 ) i 8 -cycloalkylene groups such as cyclohexylene, arylene groups such as phenylene, xylene. Their proportion generally does not exceed 30 mol% of all siloxy units. Preferred are groups such as alpha.omega-ethylene, alpha.omega-hexylene or alpha.omega-phenylene.
  • siloxy units M, D, T and Q can be distributed in blocks or randomly in the polymer chain and linked together.
  • each siloxane unit may be the same or different.
  • the indices represent average degrees of polymerization.
  • the indices are preferably as follows and are expediently chosen in accordance with the desired viscosity.
  • the aforementioned polyorganosiloxanes (A1) preferably have a structure of the general formula (Ia)
  • R and R 1 are as defined above and b1 ⁇ 3000.
  • the polyorganosiloxanes (A1) of the formulas (Ia) and (Ia ') are substantially linear and have a content of unsaturated organic groups which is preferably between 0.002 to 3.0, more preferably between 0.004 to 1.5 mmol / g.
  • the content of unsaturated organic groups refers to polymethylvinyl siloxane and must be adjusted accordingly within the given viscosity limits to siloxy groups with other substituents having different molecular weights.
  • Preferred siloxy units in the polyorganosiloxanes (A) are, for example, alkenylsiloxy units, such as dimethylvinylsiloxy, alkylsiloxy units, such as trimethylsiloxy, dimethylsiloxy and methylsiloxy units, arylsiloxy units, such as phenylsiloxy units, such as triphenylsiloxy-dimethylphenylsiloxy, diphenylsiloxy
  • the radical R is preferably present as the methyl radical with at least 90 mol% (preferably 90 to 99.99 mol% relative to Si atoms).
  • the alkenyl groups may be attached either at the chain end of a silioxane molecule or as a substituent on a silicon atom in a siloxane chain.
  • the alkenyl groups are preferably present only at the chain end of the siloxane molecule. If alkenyl groups are present on internal silicon atoms of the siloxane chains, their content in the case of the alkenyl-poor polyorganosiloxanes (A1) is therefore preferably less than 0.01 mmol / g or less than 0.0074 mol%, based on siloxane units.
  • blends of different polymers ie there are at least two polymers (A1) or at least one polymer (A1) and (A2)) with different alkenyl content and / or used different chain length, wherein the total content of unsaturated groups 3.0 mmol / g in the component (A) based on vinyl-containing polydimethylsiloxanes expediently does not exceed.
  • Both the polyorganosiloxane (A1) and the mixture of (A1) and (A2) preferably have a viscosity of 0.025 to 500 Pa.s, very particularly preferably 0.2 to 100 Pa.s at 25 0 C.
  • the polyorganosiloxane (A1) has a number of siloxy units from 20 to 3000, particularly preferably 100 to 1500 (average degree of polymerization P n , which refers to polymethylvinylsiloxane and adjust within the predetermined viscosity limits on siloxy groups with other substituents with different molecular weights accordingly is.)
  • P n average degree of polymerization
  • the alkenyl content is determined here by 1 H-NMR - see AL Smith (ed.): The Analytical Chemistry of Silicones, J. Wiley & Sons 1991 Vol. 112 p. 356 ff. In Chemical Analysis ed. By JD Winefordner.
  • a further class of preferred polymers (A) which together with (A1) can form the component (A) are vinyl-rich, optionally branched polyorganosiloxanes (A2) which, for the purpose of enhancing e.g. the tear strength or tensile strength in combination with other polyorganosiloxanes, such as those defined above, can be used.
  • branched alkenyl-rich polyorganosiloxanes are z.
  • branching units should be limited by the fact that this component should preferably be liquid, low-melting (mp ⁇ 16O 0 C) or with the other polymers (A1) miscible, transparent silicone compositions (> 70% transmission at 400 nm and 2 mm layer thickness).
  • the above-mentioned branched polyorganosiloxanes (A2) are polymers containing the aforementioned M, D, T and Q units. They preferably have the general formula (II), (IIa) to (IIb):
  • R 4 is a Ci to C 22 organic radical, such as alkyl, aryl or arylalkyl.
  • the molar ratio M: Q can assume values of 0.1 to 4: 1 or M: T of 0.1 to 3: 1, the ratio of D: Q or D: T of 0 to 333: 1, where the units M, D and T may contain the radicals R or R 1 .
  • Alkenyl group-rich branched polyorganosiloxanes include in particular liquid polyorganosiloxanes, solid resins or liquid resins soluble in organic solvents, preferably consisting of trialkylsiloxy (M units) and silicate units (Q units), and preferably vinyldimethylsiloxy units in an amount of at least 3 mmol / g. These resins may also have up to a maximum of 10 mol% of alkoxy or OH groups on the Si atoms.
  • polyorganosiloxanes (A2) have the general formula (Ia) with the proviso that they have an increased vinyl content as defined under (A2).
  • the radical R is preferably present as the methyl radical with at least 50 mol% (i.e., 50 to 95 mol% with respect to Si atoms), preferably at least 80 mol%.
  • the alkenyl-rich, preferably vinyl group-rich, polyorganosiloxane (A2) preferably has an alkenyl group content of more than 3 mmol / g to about 22 mmol / g, which relates to polymethylvinyl siloxanes and within the prescribed viscosity limits siloxy groups with other substituents on the silicon atom with a different molecular weight is to be adjusted accordingly.
  • the polyorganosiloxane (A) comprises substantially vinyl-poor linear polyorganosiloxanes (A1) as above described.
  • Vinyl-rich polyorganosiloxanes (A2) as described above can be added to improve mechanical properties, especially when the amount of filler is limited, for example, for reasons of viscosity.
  • Another preferred blend of the polyorganosiloxanes (A) contains at least two substantially linear alkenylene end-stopped polyorganosiloxanes (A1) having different alkenyl, preferably vinyl, contents.
  • the lowest possible viscosity of the silicone composition should be prescribed, on the other hand, a crosslinking structure with the Si-H compounds of component (B) defined below be made possible, which effects the highest possible mechanical strengths, such as elongation and tear propagation resistance of the crosslinked silicone rubbers. If larger amounts of short-chain alpha-omega-vinylsiloxanes (conveniently below a viscosity of 10 Pa.s) are used, this requires larger amounts of alpha, omega-Si-H-siloxanes as chain extenders to form suitable crosslinking structures.
  • An alkenyl group-containing which does not consist of a mixture of a polydiorganosiloxane of the type (A), is defined by the fact that the distribution of the weight and number average from one of the known polymerization reactions, preferably from the equilibration or polycondensation with basic or acid catalysts.
  • Such processes with alkaline or acidic catalysts are disclosed, for example, in US Pat. No. 5,536,803, column 4.
  • the average degree of polymerization P n of the polyorganosiloxanes (A), measured as number average M n by GPC and with polystyrene as standard, is preferably in the range of P n > 20 to 3000, the more preferred range is P n 200 to 1500.
  • polymers (A) defined herewith, in combination with suitable polyhydrogenorganosiloxanes of component (B) described below, permit the preparation of flowable casting compositions which have sufficiently good rubber-mechanical properties, such as elongation at break, tensile strength and tear resistance, and stability of the mechanical properties.
  • Component (B) Si-H-containing polysiloxanes
  • the polyorganohydrogensiloxanes (B) are preferably selected from linear, cyclic or branched SiH-containing polyorganosiloxanes of the general formula (II):
  • R 2 a divalent aliphatic n-, iso-, tert-, or cyclic CRCI 4 alkylene radical, or a C ⁇ -C M arylene or alkylenearyl radical, the bridging two siloxy units M, D or T,
  • the siloxy units can be present in blocks or randomly linked to one another in the polymer chain. Each siloxane unit of the polysiloxane chain may carry identical or different radicals.
  • the indices of the formula (III) describe the average degree of polymerization Pn measured as the number average Mn, determined by GPC (polystyrene as standard), which relate to polyhydrogenmethylsiloxane and are adapted within the given viscosity limits to siloxy groups having different substituents and different molecular weights.
  • the polyorganohydrogensiloxane (B) comprises, in particular, all the liquid, flowable and solid polymer structures of the formula (III) having the degrees of polymerization resulting from the abovementioned indices. Preference is given to the low molecular weight polyorganohydrogensiloxanes (B) which are liquid at 25 ° C., ie less than about 60,000 g / mol, preferably less than 20,000 g / mol.
  • the preferred polyorganohydrogensiloxanes (B) are structures selected from the group which can be described by the formulas (IIIa-IIIe)
  • a preferred embodiment of the class of compounds (MIe) and (MIf) are, for example, monomeric to polymeric compounds which can be described by the formula [(Me 2 HSiO) 4Si] m3 .
  • the SiH concentration is preferably in the range of 0.1 to 17 mmol / g, which relates to polyhydrogenmethylsiloxanes and is to be adapted within the given viscosity limits to siloxy groups with other substituents.
  • the polyorganohydrogensiloxane (B) consists of at least one polyorganohydrogensiloxane (B1) having two Si-H groups per molecule and at least one polyorganohydrogensiloxane of the type (B2) having more than two Si-H groups per molecule ,
  • component (B) consists of at least two different organohydrogenpolysiloxanes which produce different crosslinking structures to give, in conjunction with low viscosity polysiloxanes of component (A), silicone elastomers of high strength.
  • These different organo hydrogenpolysiloxanes can be assigned essentially two functions.
  • Bifunctional polyorganohydrogensiloxanes (B1) act as chain extenders, while the polyorganohydrogensiloxanes (B2) of higher functionality (> 2) act as crosslinkers.
  • the silicone composition used according to the invention preferably contains at least one bifunctional chain extender (B1) and at least one crosslinker (B2).
  • component (B1) in the silicone rubber composition of the invention examples include the chain extenders (B1) such as:
  • the crosslinkers (B2) contain compounds such as:
  • crosslinking rate is necessary, this can be achieved, for example, by increasing the ratio SiH to alkenyl, an increased amount of catalyst (d) or by increasing the proportion of polyorganosiloxanes (B2) which contain HMe 2 SiO 2 , 5 units. be achieved.
  • the chain length of the crosslinkers as component (B2) which consist predominantly of MeHSiO units, is preferably from 3 to 200, more preferably from 15 to 60 MeHSiO units.
  • the chain length of the chain extenders as component (B1) is preferably from 2 to 100, more preferably from 2 to 60 Me 2 SiO units.
  • the SiH content is determined in the present invention by 1 H-NMR see AL Smith (Ed.): The Analytical Chemistry of Silicones, J. Wiley & Sons 1991 Vol. 12 p. 356 et seq. In Chemical Analysis ed. By JD Winefordner.
  • the polyorganohydrogensiloxanes (B) can be prepared by methods known per se, for example by acidic equilibration or condensation, as disclosed, for example, in US Pat. No. 5,536,803.
  • the polyorganohydrogensiloxanes (B) can also be reaction products which have arisen from a hydrosilylation of organohydrogensiloxanes with alkenyl-containing siloxanes in the presence of the catalysts (c), the resulting SiH content preferably being within the previously defined limits. This results in R 2 - or alkylene-bridged organohydrogensiloxanes (B).
  • the polyorganohydrogensiloxanes (B) may also be reaction products resulting from the condensation of e.g. Organohydrogenalkoxysiloxanen (B) with hydroxy or alkoxysilanes or siloxanes have emerged, such. in US 4 082 726 e.g. Columns 5 and 6 described.
  • the ratio of component (B) to component (A) is preferably chosen such that a molar ratio of Si-H to Si-alkenyl units of about 0.5 to 20: 1, preferably from 1 to 3: 1 is present ,
  • the preferred amount of the polyorganohydrogensiloxanes (B) is 0.1 to 200 parts by weight based on 100 parts by weight of the component (A).
  • the component (D), the hydrosilylation catalyst preferably contains at least one metal selected from the group consisting of Pt, Pd, Rh, Ni, Ir or Ru.
  • the hydrosilylation catalyst can be used in metallic form, in the form of a complex compound and / or as a salt.
  • the catalysts can be used with or without support materials in colloidal or powdered state.
  • the amount of component (D) is preferably 0.1-5000 ppm, preferably 0.5-1000 ppm, more preferably 1-500 ppm, more preferably 2-100 ppm, calculated as metal, based on the weight of the components (A ) to (C) + (F).
  • Pt catalysts are exemplified in US 3,715,334 or US 3 419 593 and Lewis, Colborn, Grade, Bryant, Sumpter and Scott in Organometallics, 1995, 14, 2202-2213.
  • the preferred Pt ° olefin complexes are prepared in the presence of 1,3-diaminotetamethyldisiloxane (M V
  • these platinum catalysts contain, in addition to the vinyl siloxanes bound to platinum, free, non-complexed vinyl siloxanes. It may be diluted with vinyl-terminated polydimethylsiloxanes (A) to a platinum concentration of about 0.5 to 2% by weight before use for better dosage.
  • the rate of hydrosilylation is determined by the selected catalyst compound, its amount, and the type and amount of additional inhibitor component (E).
  • the carriers for the catalysts all solids can be selected as long as they do not undesirably inhibit hydrosilylation.
  • the carriers can be selected from the group of powdered silicic acids or gels or organic resins or polymers and are used in accordance with the desired transparency; preference is given to non-opacifying carriers.
  • the surface-modified oxidic fillers obtained by the process according to the invention are preferably added to the compositions according to the invention in amounts of about 0.001 to about 70 parts by weight per 100 parts by weight of the polymers or of the crosslinkable compositions (crosslinkable polymer and crosslinker). More preferred are about 1 to about 50, more preferably 5 to 40 parts by weight of the modified oxidic filler per 100 parts by weight of the polymers or crosslinkable compositions.
  • the composition according to the invention may contain one or more further fillers which are not surface-treated by the process according to the invention, as long as the solution of the problem according to the invention is not impaired. These may be, in particular, surface-poor fillers having BET surface areas of less than about 10 m 2 / g.
  • the reaction rate can be reduced, if appropriate, by addition of inhibitors (E), such as vinylsiloxanes, 1,3-divinyltetramethyldisiloxane or tetravinyltetramethyltetracyclosiloxane, at concentrations above 30 ppm of platinum.
  • inhibitors such as vinylsiloxanes, 1,3-divinyltetramethyldisiloxane or tetravinyltetramethyltetracyclosiloxane
  • Other known inhibitors can also be used, for example ethynylcyclohexanol, 3-methylbutynol or dimethyl maleate.
  • composition of the invention may further optionally contain one or more hydrosilylation reaction retarding inhibitors (E). They serve to delay the crosslinking reaction at room temperature for a certain time. Thus, at temperatures from 0 to 3O 0 C both a time-limited Inhibition (pot life) as well as a sufficiently fast and complete wettability (to the extent of free of charge) at elevated temperature.
  • E hydrosilylation reaction retarding inhibitors
  • Inhibitors are used, if not enough already by selecting the ligands of the catalyst (D) a sufficiently long processing time is achieved.
  • a preferred embodiment is the catalyst with at least one inhibitor
  • the best known class of inhibitors are the alkynols as described in US 3,445,420. These are e.g. Ethinylcyclohexanol and 3-methylbutynol and the unsaturated carboxylic acid esters of US Pat. No. 4,256,870 as well as diallylmaleate and dimethyl maleate and the fumarates of US Pat. Nos. 4,562,096 and 4,774,111, such as diethyl fumarate,
  • R w is selected from the group of d-do alkyl radicals such as methyl, ethyl, propyl, isopropyl, butyl, etc., and aryl radicals such as phenyl or benzyl, an alkenyl radical such as
  • W is independently selected from divalent C 2 -C 4 -alkylene radicals, the subscript V is 0 or 1.
  • the amount of the inhibitor component (E) is suitably chosen so that the desired crosslinking time under the selected processing conditions, in particular in coordination with the catalyst (D) and the other Components in a suitable manner, ie time and temperature can be adjusted.
  • the amount of inhibitor component (E) is preferably from 0.0001 to 2% by weight of one or more inhibitors based on the total amount of components (A) to (C) + (F).
  • the inhibitor component (E) is used, more preferably about 0.001 to 0.5% by weight, more preferably 0.05 to 0.2% by weight, based on the total amount of the components (A) to (C) + (F) preferably alkynols at metal contents of component (D) of 10 to 100 ppm added.
  • component (E) is selected from the group consisting of alkynols and vinylsiloxanes.
  • inventive compositions containing the filler according to the invention, in particular polyorganosiloxane compositions further ent contain optionally one or more auxiliaries (F), such as plasticizers or release oils, such as polydimethylsiloxane oils, without reactive alkenyl or SiH groups having a viscosity of preferably 0.001-10 Pa.s at 25 0 C.
  • auxiliaries such as plasticizers or release oils, such as polydimethylsiloxane oils, without reactive alkenyl or SiH groups having a viscosity of preferably 0.001-10 Pa.s at 25 0 C.
  • said composition contains at least one surfactant as auxiliary (F).
  • surfactant here means, in particular, a surface-active compound which in particular does not interfere with the hydrosilylation reaction, which, for example, enters into the system described above.
  • surfactants include, for example, nonionic surfactants such as polyethers, polyesters, polyamides or copolymers of these types, as well as cationic surfactants, etc. These surfactants are used, in particular in the case of polyorganosiloxane compositions in which the fillers (C) prepared according to the invention are contained, to make the surface of the cured compositions wettable or to make them more hydrophilic or antistatic.
  • the auxiliaries mentioned, in particular the surfactants (F), are preferably present in the compositions according to the invention in an amount of about 0.1 to 20 parts by weight, based on 100 parts by weight of the polymers (A) + ( B) or the crosslinkable Contain compositions (crosslinkable polymer and crosslinker) and the filler.
  • the surface-active, hydrophilic-enhancing additives are understood to be all conceivable surface-active compounds, in particular nonionic ethoxylated surfactants which contain, in addition to polyalkene oxide units, further solubilizing units such as perfluoroalkyl radicals, polyorganosiloxane radicals, alkylsiloxy radicals, alkyl radicals, alkylaryl radicals, C r C 3 o-fatty acid ester radicals , Fatty alcohol radicals or C 2 -C 20 -alkylphenolpolyether radicals may contain.
  • nonionic ethoxylated surfactants which contain, in addition to polyalkene oxide units, further solubilizing units such as perfluoroalkyl radicals, polyorganosiloxane radicals, alkylsiloxy radicals, alkyl radicals, alkylaryl radicals, C r C 3 o-fatty acid ester radicals , Fatty alcohol radicals or C 2 -C 20 -al
  • the surfactants include, for example, polyhydroxylated fatty alcohols, amides of polyethers or polyalcohols, polyhydroxylated fatty amines, polypropylene oxide compounds or polyethylene oxide compounds.
  • surfactants also include polyether siloxanes, wherein the polyether group is selected from polyethylene oxide or polypropylene oxide and these
  • polyalcohols such as alkylglucosides, alkylpolyglucosides, sugar esters, sugar esters, sugar glycerides, esters of sorbic acid.
  • the surface-active compounds can be present individually or as a mixture.
  • alkylbenzene sulfonates alkyl sulfates, alkyl ether sulfates, and alkylaryl ether sulfates.
  • alkyl succinates also include alkyl succinates, the alkyl carboxylates, the derivatives of hydrolyzed proteins, alkyl phosphates, aryl phosphates, alkyl ether phosphates, if appropriate their alkali metal or alkaline earth metal salts or mixtures with the abovementioned surface-active agents.
  • the surface-active compounds may also include cationic surfactants such as trialkyl ammonium benzyl halides, tetraalkyl ammonium halides or mixtures thereof.
  • surfactants such as alkyl betaines, alkyl dimethyl betaines, alkyl amidopropyl betaines, alkylamidopropyl dimethyl betaines are also suitable.
  • Surfactants also include alkyltrimethylsulfobetaines, derivatives of imidazolines, such as the alkylamphoacetates, alkylamphodiacetates, alkylamphopropionates, alkylamphodipropionates, alkyl sultans, alkylamidopropylhydroxysultes, condensation products of fatty acids, and hydrolyzates of proteins.
  • alkyltrimethylsulfobetaines such as the alkylamphoacetates, alkylamphodiacetates, alkylamphopropionates, alkylamphodipropionates, alkyl sultans, alkylamidopropylhydroxysultes, condensation products of fatty acids, and hydrolyzates of proteins.
  • alkyltrimethylsulfobetaines such as the alkylamphoacetates, alkylamphodiacetates, alkylamphopropionates, alkylamphodipropionates, alkyl
  • the surfactants (Fa) and (Fb) are preferably soluble in polyorganosiloxanes, ie there is no segregation, if 10 wt.% Polyether or polyether siloxane present in a polyorganosiloxane having a viscosity of 10 Pa.s at 25 0 C.
  • the surfactants (Fa) and (Fb) suitably contain one or more solubilizing groups which suppress this segregation.
  • the polyethersiloxanes (Fb) preferably also contain at least one unsaturated aliphatic or cycloaliphatic C 2 -C 10 -group, which together with SiH groups can be converted into SiC bonds in a hydrosilylation reaction.
  • the surfactants (FA) suitably contain as solubilizing groups, for example preferably one or more hydrocarbon or perfluoroalkyl groups, which render the surfactants soluble or dispersible in the crosslinking systems, in particular the polyorganosiloxanes.
  • the surfactants (Fb) are useful as solubilizing groups additionally one or more polyorganosiloxane groups.
  • (Fa) and (Fb) may contain hydrophilic groups which impart a hydrophilic surface to the crosslinked compositions of the invention.
  • Ethoxylated surfactants which contain a hydrocarbon-matrix-solubilizing group, ie are fat-soluble, are described in "Surfactants and Detersive Systems", Kirk-Othmer Encyclopedia of Chemical Technology, 3rd Ed., 22, 360-377 (1983). Ethoxylated surfactants are furthermore described, for example, in US Pat. Nos. 3,505,377, 3,980,688 and 4,431,789. Furthermore, it is preferred that the polyethersiloxanes (Fb) themselves have a Pt-containing content of less than 1 ppm.
  • the surfactant must be present in a sufficient amount with a sufficient number of hydrophilic groups in order to be able to provide the surface of the polymer, such as that of the crosslinked silicone elastomer, with sufficient hydrophilicity.
  • the preferred amount of the hydrophilic additive of the present invention will be in the range of 0.1 to 30 weight percent, more preferably 1 to 15 weight percent, most preferably 3 to 10 weight percent of the total composition.
  • Sufficient wettability is characterized in that the contact angle of the crosslinked silicone composition has a 3-minute value below 65 °.
  • the term ' 3-minute contact angle ' means a contact angle formed by a drop of distilled water applied after 3 minutes of crosslinking to a cured polymer, particularly silicone surface. It can be measured at 25 ° C. with a goniometer (eg Model 100 from Rame-Hart, Ine, Mountain Lakes, NJ). The measuring method has been described in W. NoII, "Chemistry and Technology of Silicones” (1982) pp. 447-448.
  • a measurement is carried out in such a way that, in particular, the silicone composition is cured on a smooth surface, for example a glass or polished metal surface, and after the mold surface and crosslinked silicone elastomer have been separated, a drop of water is applied to the smooth, cured silicone topcoat. area brings.
  • the compositions according to the invention preferably have a 3-minute value against water of below 45 °, more preferably of below 30 °, most preferably of below 10 °.
  • the size of the contact angle depends strongly on the amount of the surfactant on the surface of the polymer, such as the silicone elastomer. In general, the amount of surfactant on the surface increases with increasing amount of ethylene oxide units in the surfactant. The contact angle decreases to the same extent.
  • the surfactants (F) which are preferably used according to the invention may in principle be those which have reactive groups which lead to incorporation into the polymeric siloxane network, or are those which have no reactive groups which they contain
  • the surfactants which contain no reactive groups which make them capable of incorporation into the polymeric network can be, for example, the above-described surfactants, in particular non-reactive polyether compounds.
  • the surfactants which contain reactive groups which make them capable of incorporation into the polymeric network when using the hydrosilylation reaction may be, for example, those which contain reactive groups selected from hydroxyl groups, Si-alkenyl groups, alkenyloxy groups, such as Allyloxy, and Si-H groups.
  • both the surfactants (Fa) and (Fb) may have reactive groups.
  • the choice of reactive groups depends on the nature of the reactive groups of the crosslinkable polymer system used. In principle, it can therefore be any desired functional group which can participate in the crosslinking of the crosslinkable polymer system. However, it may also be any other functional group capable of reacting with the crosslinking groups of the crosslinkable polymer system. These include, for example, OH groups which can form SiOC or SiOSi bonds, but also other organofunctional groups such as epoxy, halogen, amino groups, which can bond to the Si functionalized moieties on the Si, when in the polyanagnosiloxane composition, the crosslinking or vulcanization by hydrosilylation is initiated or the composition is heated to at least 6O 0 C. , As a result, in a preferred embodiment, these reactions lead to binding of the hydrophilizing surfactant to the polyorganosiloxanes.
  • curable polysiloxane compositions which are preferably crosslinked by hydrosilylation reaction, come in particular alkenyl-containing surfactants, in particular polyether compounds in question, the terminal Alkenyl- bezw. Wear cycloalkeny groups.
  • alkenyl group-containing surfactants include, for example, the linear, cyclic or branched polysiloxane-polyether copolymers described in US Pat. No. 6,013,711, which are selected, for example, from the following formulas:
  • the values of the indices m, p, q, r and v in the formulas (IV) are preferably selected such that the total number of silicon atoms per molecule is 2 to 20, preferably 2 to 10, more preferably 2 to 5, inclusive in that there is at least one Z and at least one R 5 per molecule, v has the value 0 to 1; with 3>m> 0 and 0> q and p ⁇ 3.
  • R is as defined above.
  • R is preferably methyl, particularly preferred is a trisiloxane.
  • R 5 is a CrC 20 , preferably unsaturated, monovalent organic d-Ci 2 group, which can be hydrosilylated with SiH groups and then forms a Silizium-Kohlenstoffbin fertil.
  • unsaturated groups which represent R 5 are alkenyl groups, for example the vinyl, allyl, methallyl, 5-hexenyl, vinylcyclohexyl, limonyl,
  • R 5 may be phenyl or 3,3,3-trifluoropropyl.
  • R has the meaning as defined above and preferably represents a saturated, monovalent organic d-Ci 2 group.
  • the radical R can also be a functionalized organic group R f , such as the chloropropyl, Heptafluorisopropyl-, C 6 Fi 3 -ethylene , 3,3,3-trifluoropropylaminoalkyl, epoxyalkyl and cyanoethyl groups.
  • Suitable ethoxylated surfactants containing perfluoroalkyl groups as solubilizing groups are described in US 2,915,544 or US 4,484,990.
  • Z is a polyether-containing group which preferably binds to a polyorganosiloxane block via a silicon-carbon bond.
  • Z has the general formula (Va): R '- (OC 2 H 3 R) ⁇ (OC 3 H 6 ) y R 2 - (Va)
  • R ' is R or hydrogen and R 2 are as defined above and R' is preferably R f and x is an integer in the range 1-20, preferably 2-8 and y is an integer from 0 to 5.
  • the oxyalkylene groups for the polyether part of one type of these copolymers are the oxyethylene, oxy-1,2-propylene, oxy-1,2-butylene, oxy-2,2-dimethyl-1,3-propylene group and like.
  • the polyether portion of the copolymer may contain oxyalkylene units of one or more types. For the optimum of hydrophilicity, it is desirable that at least 40% by weight and preferably at least 50% by weight of the oxyalkylene or alkyleneoxy groups are ethyleneoxy groups.
  • R 1 is hydrogen or a linear or cyclic C 1 -C 9 -alkyl or C 1 -C -acyl group or a vinyl, ether or organosilyl group.
  • the radicals R 1 which are exemplary of alkyl groups are methyl, tert-butyl and 2-ethylhexyl.
  • acyl end groups are acetoxy, acetoacetoxy, acryloxy, methacryloxy and benzoyl groups.
  • Organosilyl end groups include the saturated trialkylsilyl groups such as trimethylsilyl, triethyl, ethylisopropyl, tert-hexyldimethyl, tert-butyldimethyl, tert-butyldiphenyl; the unsaturated end groups include groups such as vinyldimethyl, divinyloctyl, ethynyldimethyl and Propynyldimethyl groups.
  • OH-terminated polyether molecules are often present as starting material during the synthesis of the polysiloxane-polyether copolymers.
  • nominally terminated copolymer products may also contain non-terminated polysiloxane polyether copolymers.
  • Z is as defined above and is preferably Z1 with
  • Z1 - (CH 2 J 3 O (C 2 H 4 O) I -20
  • R 'and R' H, C 1 -C 18 -alkyl, - (CH 2 ) 3 O (C 2 H 4 O) 7, 5 CH 3 , - (CH 2 J 3 O (C 2 H 4 O) 5 (C 3 H 6 O) 2 H, or - (CH 2 J 3 O (C 2 H 4 O) 3 CH 3 ,
  • x is selected to be sufficiently large and y is selected to be sufficiently small to achieve the desired 3 minute value for to achieve the water contact angle.
  • the polyethers may be random or block-structured polymers of different alkylene oxides. However, it is preferable to construct polyether units of essentially ethyleneoxy and propyleneoxy units, of which in turn the block copolymers are preferred in the presence of C2 and C3 units. In particular, however, it is preferred that the polyether has only ethylene oxide units with C1-Cig-alkyl end groups.
  • SILWET® General Electric Silicones
  • Preferred SILWET surfactant types are copolymers such as SILWET L-77, L-7600 and L-7602.
  • polyethers (Fb) may be polyethersiloxanes of the formula (VIII):
  • R 7 is independently a monovalent hydrocarbon radical, with the proviso that the majority (> 50 mol%) of R 7 are sterically hindered sec- or tert-C 3 -C 18 -alkyl or cycloalkyl groups with c> 4, d> O, and with the further proviso that, by the appropriate choice of c and d, they are small enough to set the aforementioned ' 3-minute value ' for the contact angle on the surface of the crosslinked elastomer.
  • T is hydrogen or a monovalent alkyl or alkenyl radical or a group of the formula -Si (R) [OSi (OR 7 ) 3 ] 2 .
  • T is -CH 3
  • R 7 is sec-butyl
  • c is> 5
  • d O.
  • Exemplary ethoxylated surfactants of formula (VIII) are described in US Pat. Nos. 4,160,776; US 4,226,794 and US 4,337,168. The products were, for example, under the name "SILFAC” Fa. ONn Corp. available as polyethoxylated silicates such as SILFAC 12M.
  • compositions of the invention may be present in admixture with the other individual components of the composition and stored as conventional curable silicone compositions.
  • the surfactant may expediently be present in all or one of the components in order, if appropriate, to react with a reactive component of the multicomponent silicone compositions, as in the case of remaining SiH 2.
  • Groups in a silicone polyether polymer to exclude.
  • mold release agents such as fatty acid or fatty alcohol derivatives, colorants and / or color pigments or stabilizers may be used as adjuvant (F).
  • the stability to hot air exposure can be increased, for example, with known hot air stabilizers, such as Fe, Ti, Ce compounds in the form of their oxides, inorganic and organic salts and complexes but a number of organic antioxidants.
  • one or more non-curing partial mixtures can be provided in a manner known per se, which are mixed with one another before the application or curing to form the curing composition, and wherein at least one the said, non-curing sub-mixtures containing the modified oxidic filler according to the invention.
  • an addition-crosslinking silicone rubber mixture is prepared by preparing at least two partial mixtures (1) and (2) which comprises more than one but not all of the components (A) to (F) and the filler according to the invention.
  • the preferred division into partial mixtures serves to improve handling and storage, in which the reaction of the hardening components with one another is achieved by dividing the reactive and catalyzing components containing constituents (A) to (F) and the filler according to the invention until immediately before mixing - can postpone all components before mixing.
  • a partial mixture (1) consisting of the components (A), filler and (C) and optionally (D) and (F), as well as a partial mixture (2), consisting at least of Component (B) and optionally filler, (E) and (F) prepared by mixing.
  • all possible sub-mixtures can be used for a longer storage, as long as the components (A), (B) and (C) are not present simultaneously in a partial mixture. Therefore, it is convenient to separate component (B) and (C) when simultaneously (A) is present or when one separates (B) and (A) when (C) is present in the same part mixture at the same time.
  • the component (C) can be kept more or less advantageously in each of the components, as long as the mutually reacting grain components (A), (B) are present side by side.
  • the inhibitor (E) can be present in each partial mixture, the combination in a partial mixture with (B) being preferred.
  • compositions described above which contain the surface-modified oxidic fillers obtained by the process according to the invention are used, for example, for the production of molded articles, impression compounds or coatings.
  • the fillers produced according to the invention serve to reinforce the (rubber) mechanical properties.
  • Preferred examples of said shaped articles are, for example, impression compounds, such as dental impression compounds, replica forms, gaskets, such as so-called “formed-in-place” gaskets, so-called “conformal coatings", any shaped articles, such as (embossing ) Stamping and (embossing) pressure pads for the "padprinting” process, printing inks (low viscosity compositions for marking or labeling flexible substrates, such as indexable mats)
  • the filler modified according to the invention is used to prepare hydrophilic silicone rubber compositions containing it by way of example have the following components:
  • R ' C 1 -C 9 -alkyl
  • compositions containing the fillers according to the invention are expediently obtained by curing the compositions containing the fillers according to the invention.
  • the compositions are poured into molds or offered as a curable casting material.
  • mixture A 150 g of mixture A were mixed with 165 g of the vinyl-terminated polydimethylsiloxane having a viscosity of 1 Pas mixed and obtained in this way a mixture B with a concentration of 15 wt.% Of silica.
  • the weight fraction of trimethylsiloxy groups taken up by the filler surface in the above process was not taken into account in the calculation.
  • 98.6 g of the mixture B 1.6 g of a trimethylolpropane-started polyether having a molecular weight of about 6000 and an EO: PO ratio of 30: 70 was mixed. This resulted in a no longer flowing mixture.
  • This polyether-containing blend and blend B without polyether additive were measured in a rotary mode using a Bohlin cone / plate geometry rheometer. The measurement began at a shear rate of 0.1 [s "1] nand 25 0 C. The shear rate was reduced to 10 [s" increased 1], and then backwards again reduced to 0.1 [s "1] The return curve. evaluated.
  • This example demonstrates the strong thickening effect of the polyether in a blend of polydimethylsiloxane and hydrophobic silica made according to the prior art, as described for example in US 4,101,499, US 4,162,243 or in US 5,777,002 Technique was hydrophobicized.
  • This comparative example shows the behavior obtained by adding further hexamethyldisilazane after mixing in the silica without first removing the volatiles.
  • Such a method as described in US 4,785,047 or WO 98/58997 or WO 00/61074, brings no improvement.

Abstract

L'invention concerne un procédé de fabrication d'une charge oxydique traitée en surface, des compositions contenant ladite charge ainsi que leur utilisation.
PCT/EP2005/053659 2004-07-28 2005-07-27 Procede de fabrication d'une charge oxydique traitee en surface WO2006010764A1 (fr)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006061057A1 (de) * 2006-12-22 2008-06-26 Wacker Chemie Ag Organofunktionelle Silikonharzschichten auf Metalloxiden
WO2009077437A1 (fr) * 2007-12-19 2009-06-25 Wacker Chemie Ag Hydrophobation de silices en conditions oxydantes
EP2436735A1 (fr) * 2010-09-30 2012-04-04 Sika Technology AG Composition silicone bi-composants

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Publication number Priority date Publication date Assignee Title
DE19507878A1 (de) * 1994-03-10 1995-09-14 Gen Electric Verfahren zum Behandeln von Füllstoff in situ für RTV-Silicone
EP0849331A2 (fr) * 1996-12-21 1998-06-24 Hüls Silicone Gesellschaft mit beschränkter Haftung Procédé de préparation de mélanges-maítre de polymères de silicone fortement chargés
US6013711A (en) * 1997-06-18 2000-01-11 Ck Witco Corporation Hydrophilic polysiloxane compositions
US6762242B1 (en) * 1999-04-09 2004-07-13 Rhodia Services Hydrophilic silicone elastomer material used in particular for impressions

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19507878A1 (de) * 1994-03-10 1995-09-14 Gen Electric Verfahren zum Behandeln von Füllstoff in situ für RTV-Silicone
EP0849331A2 (fr) * 1996-12-21 1998-06-24 Hüls Silicone Gesellschaft mit beschränkter Haftung Procédé de préparation de mélanges-maítre de polymères de silicone fortement chargés
US6013711A (en) * 1997-06-18 2000-01-11 Ck Witco Corporation Hydrophilic polysiloxane compositions
US6762242B1 (en) * 1999-04-09 2004-07-13 Rhodia Services Hydrophilic silicone elastomer material used in particular for impressions

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006061057A1 (de) * 2006-12-22 2008-06-26 Wacker Chemie Ag Organofunktionelle Silikonharzschichten auf Metalloxiden
WO2008077814A3 (fr) * 2006-12-22 2009-06-04 Wacker Chemie Ag Couches de résine silicone organofonctionnelles sur des oxydes métalliques
WO2009077437A1 (fr) * 2007-12-19 2009-06-25 Wacker Chemie Ag Hydrophobation de silices en conditions oxydantes
JP2011506259A (ja) * 2007-12-19 2011-03-03 ワッカー ケミー アクチエンゲゼルシャフト 酸化条件下でのシリカの疎水化法
KR101259244B1 (ko) * 2007-12-19 2013-04-29 와커 헤미 아게 산화 조건 하에 실리카의 소수화
US8470443B2 (en) 2007-12-19 2013-06-25 Wacker Chemie Ag Hydrophobicization of silicas under oxidizing conditions
EP2220172B1 (fr) 2007-12-19 2016-03-02 Wacker Chemie AG Hydrophobation de silices en conditions oxydantes
EP2436735A1 (fr) * 2010-09-30 2012-04-04 Sika Technology AG Composition silicone bi-composants
WO2012041952A1 (fr) * 2010-09-30 2012-04-05 Sika Technology Ag Composition de silicone à deux composants
US9228119B2 (en) 2010-09-30 2016-01-05 Sika Technology Ag Two-component silicone composition

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