SE529440C2 - Dispersible silica powder - Google Patents

Abstract

1. Object of the invention is a process for making silica particles, comprising the following steps: 1) An alkali stabilized silica sol with a particle size in the range from 8 to 250 nm is diluted to at most 30 % SiO2 with water and/or a water-soluble organic solvent 2) A silane and/or an organic compound, selected from polyols und dicarboxylic acids, is pumped into the agitated sol of step 1, which is maintained at a temperature between 20 and 75 °C, 3) The sol of step 2 is deionized by contacting it with anion and cation exchange resins 4) The silylated, deionized sol of step 3 is dried by evaporating the water, preferably under vacuum or in an air stream, 5) optionally, the dried sol of step 4 is milled to a fine powder, whereby at least two of the steps 2), 3) and 4) may be carried out in a different order.

Description

529 440 A2. certain minimum value, the nature of the surfaces becomes property-determining even if the internal composition and structure of the particles are also important. The specific surface area is the ratio between the exposed surface area and the mass of the particles and is usually expressed as square meters per gram (m2 / 9). Surface phenomena of solids become increasingly important as specific surface area increases. A specific surface area of about 1 m2 / g can be considered a threshold value, below which surface phenomena can be neglected. For solid, mainly round silicic acid particles, this means an average particle diameter of about 2-3 microns. As the particle size of such particles decreases, the specific surface area increases. As the specific surface area reaches 25 nf / g, or more, the nature of the surface becomes increasingly important and it can e.g. interact strongly with the molecular chains of polymers.

Colloidal particles of silicic acid have reached widespread use in many areas. Among other things, they have been used to fill, extend, thicken and strengthen various organic materials such as plastics, resins, rubber, oils, etc.

U.S. Patent 2,727,876 discloses that a silicic acid powder consisting of aggregates of spherical particles having diameters down to 5 to 7 nanometers whose surface is esterified is readily dispersed in natural rubber. The resulting elastomers give vulcanizates with extremely high tensile and tear strength and elongation. U.S. U.S. Pat. No. 2,974,105 discloses stable organosols of amorphous, solid, substantially non-aggregated silicon spheroids, which are preferably surface esterified, dispersed in alkoxy-substituted ethanols. The organosols can be used to incorporate very fine silicic acid particles such as fillers in polymeric polymers. .

U.S. U.S. Pat. No. 2,786,042 discloses alkali-stabilized aqua and organosols of amorphous silica colloidal particles having an average diameter of from 10 to 150 nanometers.

The particles have monovalent hydrocarbon radicals chemically bonded directly to at least 5% of the silicon atoms in the surface. The organosols are a medium for dispersing colloidal silicic acid as fillers in polymers to improve tensile compression and shear strength. European Patent Application 1,236,765 A1 discloses organosols of colloidal particles of amorphous silicic acid having an average diameter of from 3 to 50 nanometers in polyols, polyamines, linear or branched polyglycol ethers, polyesters and polylactones and their use to make polymers with improved mechanical properties.

PCT application WO 01/05883 A1 claims solid or cellular polyurethanes containing from 0.01 to 20% by weight of discrete, non-aggregated silicic acid particles having an average diameter of from 1 to 500 nanometers. The filler of silicic acid is incorporated into the PUR elastomer by mixing an aquasol or organosol of silicic acid particles in solvents such as e.g. alcohols, low molecular weight diols and alkanes with higher molecular weight polyhydrols and / or low molecular weight chain extenders and / or crosslinkers. Water and / or organic solvent is removed by e.g. distillation.

European patent application 0 236 945 A2 discloses a 3-step process for making a monodisperse glycol suspension comprising small, spherical particles of an amorphous inorganic oxide, e.g. silicic acid, with an average diameter from 0.05 to 5 micrometers suspended in a glycol. In the first step, particles of a metal oxide are made by adding a hydrolyzable organic compound, e.g. tetramethylorthosilicate, to an aqueous solution of an alcohol, perhaps containing a glycol included in step 2. In the second step, the alcohol is replaced with a glycol resulting in a glycol suspension of the small particles. In the third step, a monodisperse glycol suspension of the small particles is obtained by heat treatment.

The product according to the invention is claimed to give polyester films improved smoothness.

U.S. U.S. Patent 6,136,92 and U.S. Patent Application 2001/0027223 disclose liquid silicoacrylic compositions containing a multifunctional acrylic monomer, a silane and discrete silicic acid particles having an average diameter between 5 and 100 nm which can be thermally polymerized or by radiation.

Polymerization, e.g. by radiation, of such a composition 529 440 11 results in transparent, clear films with excellent scratch and wear resistance.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to describe methods for making polymeric materials which contain silicic acid particles in the form of powders which can be easily dispersed in liquid or molten organic compounds. Another object is to provide methods for preparing such a powder in which the silicic acid particles are present as solid primers with a diameter of from 8 to 250 nm. Yet another object is to provide such powders in which the surface of the particles has been modified to modify its chemical nature in a controlled manner; eg by reacting the silanol groups of the surface with silanes.

The powder is used as a reinforcing filler in polymers. It can be dispersed in polyols, isocyanates, carboxylic acids and other raw materials for the production of polyurethanes, polyesters and polyamides. It can also be dispersed directly in molten polymers in extruders.

In other embodiments of the invention, the powder is incorporated into nanocomposites of polyurethanes, polyesters and polyamides. Particularly important embodiments of the invention are nanocomposites of the powder and urethane, ester and amide based thermoelastics, in which the blocks of soft segments dominate over the hard segment blocks in the domain structure which characterize such polymers.

Other polymer properties can also be improved with powders of this invention. Thus, e.g. polyester films often in magnetic strips, optical photography, capacitors and packaging materials, but the low slipperiness of the films causes problems in production, handling and use. The content of polyester films can be improved with powders according to this invention. In other embodiments of the invention, powders may be introduced into a variety of organic media. They can be mixed with liquid lubricants such as hydrocarbon oils, fluorocarbons, silicone oils, vegetable oils and polyether oils, thus providing improved viscosity, wetting, body, and water resistance in many uses of these materials.

Another object of this invention is to improve propellants, e.g. diesel, by dispersing the silicic acid particles of the powder therein and thus providing a catalytic surface for improved combustion.

In yet another embodiment of the invention, waxes, especially those used in coating paper, can be improved by adding these silicic acid powders. The waxes get more "body" in hot condition so that thicker coating is achieved with a single dip, and sticking in hot weather is prevented.

Wax formulations containing pastes of waxes and waxes dissolved in organic solvents can be advantageously modified with powders according to this invention.

Detailed Description of the Invention Silica Particles The raw materials for the silica particles of the present invention are commercial silica sols. Such sols are dispersions in water of spheres of silicic acid without an inner surface or detectable crystallinity. They are usually alkaline by the addition of an alkali hydroxide, usually sodium hydroxide, which reacts with the surface of the particles to form a negative charge. This causes the particles to repel each other and thereby achieve a stable dispersion.

There are also silicic acid sols in which the particles have a positive charge and are dispersed in an acidic environment.

The dry matter content depends on the particle size and varies from about 15% by weight for the smallest particles, 4 to 5 nm, to about 50% by weight for larger particles,> 20 nm. The surface of the particles in aqueous silicic acid sols is covered with surface hydroxyl groups, silanol groups.

Stabilization of commercial silicic acid sols is accomplished by adjusting the pH of the sol to between 8.0 and 10.0 by the addition of alkali, usually a solution of sodium hydroxide.

The sols also contain small amounts of other electrolytes such as sodium chloride and sodium sulfate.

The stability of highly concentrated silicic acid sols, aqueous sols as well as organosols, is very sensitive to electrolytes. The content of electrolytes can be reduced to a minimum by deionizing the suns. This can be accomplished by contacting a silicic acid sol with a cation exchange resin which removes cations, mainly sodium ions, or a mixture of anion and cation exchange resin which removes both anions and cations. The industry is well versed in techniques for deionization. The dry content of this kind of sols can be made high and the high purity makes them particularly suitable for certain purposes of the present invention.

When commercial silicic acid sols are dried by removing the water, the dry sol in the form of flakes or a powder cannot be redispersed in water or organic solvents.

Commercial silica sols are sold under various trade names, e.g. Bindzil® from EKA Chemicals, Sweden.

Ludox® from W.R. Grace, U.S.A., Nalcoag®> from Nalco, U.S.A., Levasil® from H.C. Starck, Germany, Klebosol® from Clariant, France, and Snowtex® from Nissan, Japan.

Süaner The general formula for the silane-type coupling substances used in this invention has functionality of two kinds.

The two ends of the YnSiXMq-Q Silane molecule can be chemically modified, either individually or simultaneously. The X group can be replaced or hydrolyzed without affecting the Y group, or the Y group can be modified without changing the X group. In some cases, the Y group is modified in an aqueous environment in which the X groups are hydrolyzed.

Chemical modification of the Y group may precede bonding to a surface or may take place on the surface after silylation. 529 440 74 The X group can react with hydroxyl groups on the surface of inorganic substrates. The bond between X and the silicon atom in coupling substances is replaced by a bond between the inorganic substrate and the silicon atom. X is a hydrolyzable group, e.g. alkoxy, acyloxy, amine or chlorine groups. The most common alkoxy groups are methoxy and ethoxy, which give methanol and ethanol as by-products in the coupling reaction. Since chlorosilanes produce hydrochloric acid as a by-product in coupling reactions, they are generally not used as much as alkoxysilanes.

Y is a non-hydrolyzable group which may be organoreactive or non-organoreactive. If it is organoreactive, the coupling agent can bind to organic resins and polymers.

Organosilanes can have one, two or three organic substituents. The most common silanes are those with an organic substituent.

In most cases, the silane is hydrolyzed before treating the surface of the substrate. After hydrolysis, reactive silanol groups are formed which can condense with other silanol groups, e.g. such on the surface of silicic acid filler, forming siloxane linkages. Stable condensation products are also formed with other inorganic oxides, e.g. oxides of aluminum, zirconium, tin, titanium and nickel, which have hydroxyl groups on the surface.

Water for hydrolysis can come from different halls. It can be added, it can be on the surface of the substrate or it can come from the atmosphere.

The reaction of silanes takes place in several steps. Initially, the labile X groups attached directly to silicon are hydrolyzed. Then condensation takes place between hydrolysed silanes to siloxanes or with hydroxyl groups on the substrate surface. If the formation of oligomers predominates, the oligomers hydrogen bond with OH groups on the surface of the substrate. Upon drying or curing, covalent bonding with the substrate surface is finally formed during water splitting.

Some commercially available organo-reactive silanes are shown in Table 1. 529 440 8 Table 1. Organo-Reactive Silanes Chemical name Formula Molecule 'K ° k' at point ° C Aminoethylaminopropyl- nmcfhcnzmcmcfrcmsxocn.) 222 - 35 264 trimethoxysilemoxymamanopropylminopropyl 37 122 Vinyltrimethoxysilane Cmä ß ß næh 148-23 125 3-Glycidoxypropyl- / R \ 236-34 262 trimethoxysilane C fl zcncmocnzc fl zclhsñocnà 3-Methacryloxypropyl- / pm 243-35 259 trimethoxyscnoc.

Some commercially available, non-organo-reactive silanes are shown in Table 2.

Table 2. Non-organo reactiva silanes Chemical Name Formula Molecular Weight Boiling weight ° C methyltrimethoxysilane mgSiKmHy3 136.23 103 dimethyldimethoxysilane (c fl gzsi al mngz 120.22 81 isobutyltrimethoxysilane ic¿ @ siKmHg3 178.30 155 Fenyltrimetoxisilane C¿gsi «xm3) 3 198.29 219 methyltrichlorosilane C fl ßich 149.48 66 dimethyldichlorosilane ( c fl gzs fl nê 129.06 70 Trimethylchlorosilane (c fl gasicl 108.64 58 Trialkoxysilanes, RSi (OR) 3, and dialkoxysilanes, R2Si (OR) 2, are gradually hydrolysed in water to the corresponding silanols which can be condensed into siloxanes. Increased organic substitution hydride, ie.

(Me) 3SiOMe> (Me) 2Si (OMe) 2> MeSi (OMe) 3. The rate of hydrolysis of alkoxy groups generally depends on how bulky they are. A 529,440 * l methoxysilane hydrolyzes e.g. 6-10 times faster than an ethoxysilane. Acid hydrolysis is significantly faster than alkaline hydrolysis and is slightly affected by other, carbon-bonded substituents. The rate of condensation of alkoxysilanes depends on the degree of organic substitution and follows the same trends as the rate of hydrolysis of the corresponding organically substituted alkoxysilanes. The reaction rates are strongly dependent on pH but, under common conditions, pH 3.5-5.5, the hydrolysis takes place comparatively fast (minutes) while the condensation reaction is much slower (hours). The most common way to silylate the surface of conventional fillers such as clays is by deposition from an aqueous alcoholic solution. A solution of 95% ethanol and 5% water is adjusted to pH 4.5-5.5 with e.g. acetic acid. The silane is added with stirring to a content of e.g. 2%. The solution is allowed to stand for five minutes for hydrolysis and silanol formation.

Particulate fillers and fiberglass are silylated by stirring them in the silane solution for 2-3 minutes and decanting the solution. Deposition from aqueous solutions is used for most commercial fiberglass systems. The alkoxysilane is dissolved to a content of 0.5-2.0% in water. For less soluble silanes, 0.1% nonionic tensed is added to the water and an emulsion rather than a solution is obtained. If the silane does not contain any amine group, the pH of the solution is adjusted to 5.5 with acetic acid.

The solution is sprayed on the substrate or used as a dip bath.

Silanes are commercial products that can be obtained from e.g.

Dow Corning in the United States and Degussa in Germany.

Silylation of the surface of silicic acid particles with silanes Silylation of the surface of small silicic acid particles according to the present invention is a completely different process compared to silylation of the surface of conventional fillers such as clays and fiberglass Colloidal silicic acid used in the present invention is a dispersion of discrete, non-aggregated, uniformly sized, spherical silicic acid particles in water.

The silylation procedure must be performed under conditions 529,440 IO of pH, concentration, rate of addition of silylation solution and temperature that the particles do not aggregate to form irreversible siloxane bonds with each other.

The stability of silica sols against gelation decreases with increasing content of silicic acid, SiO2. Commercial sols are manufactured with the highest possible silicic acid content, which depends on the particle size, compatible with long-term stability against gelation. Although the silylation process can be carried out at silicic acid levels approaching the levels of commercial sols, it is desirable to use lower silicic acid sols. At concentrations of about 15% SiO2, the average distance between particles is a particle diameter, which results in only moderate interaction between the particles and good stability against gelation.

The silylation solution may be the silane as such, or this in admixture with water and a water-soluble organic solvent, e.g. an alcohol such as ethyl or methyl alcohol, or in a water-soluble organic solvent such as ethyl or methyl alcohol. The silane content is limited by the requirement that the silane molecules must not have time to hydrolyze and condense to polysiloxanes within the time frame of the silylation process. In the present invention it has been found that about 2% of silane is a suitable content but higher levels can be used and are sometimes preferred. In a procedure for preparing silica powder according to the present invention, undiluted silane is added to the silica sol to be silylated.

The pH of the system during the silylation procedure should be such that the silane, hydrolyzed to the corresponding silanol, reacts easily with the OH groups on the surface of the silicic acid particles but does not destabilize the sun. In conventional silicic acid technology, it is well known that the size of the particles in a silicic acid sol can be increased by allowing the silanol groups on the surface of the particles to react with monomeric silicic acid. Such particle size build-up occurs best at 529,440 H pH above 8, preferably between 9 and 10. Silanol groups on silicic acid particles react similarly with the hydroxyl groups on hydrolyzed silanes at pH above 8 to form a coating of organic groups on the particle surface without risking the sun stability within the time frame of the silylation procedure. In conventional silane technology, the surface of fillers such as clays and fiberglass can be easily modified by reacting hydroxyl groups on the surface of the filler with silanols at pH between 3.5 and 5.5. If the silane contains amine groups, the pH of the system must be alkaline in order for the silane molecule to be able to target the surface correctly; i.e. it must approach the particle with the OH groups closest to the surface.

In an acidic environment, the amine groups are positively charged and silanols with amine groups therefore approach the particles with the amine group closest to the weakly negatively charged particle surface and condensation between the OH groups of the silanol molecule and the particle surface does not occur.

The rate of the condensation reaction, like that of any other chemical reaction, increases with temperature while the stability of silica sols decreases with temperature. A temperature of 20-50 ° C allows fast and efficient reaction of the silane with the particle surface without risking the stability of the sun.

Silylation of particulate filler surfaces by deposition from, for example, aqueous alcoholic solutions takes place with ease and is accomplished by stirring the filler particles in the silylation solution for 2-3 minutes.

Silylation of colloidal silicic acid also occurs readily according to the present invention and can be accomplished in a matter of minutes. However, so as not to risk the stability of the colloidal silicic acid, it is preferable to adjust the rate of addition of silylation solution of silylation solution to the suspension of colloidal silicic acid particles so that the silylation of the particle surface takes place over a period of hours instead of minutes. The degree of silylation, expressed as the number of silane molecules per square meter of particle surface area required to give a dispersible powder depends on the chemical structure of the silane but is in the range 1.0 to 7.0, preferably 3.0-4.0, silane molecules per square meter of particle surface area. .

Powders of sols of silylated silica particles The removal of water and alcohol, e.g. methanol or ethanol, from the suspension of silylated silicic acid particles' must take place under conditions of pH and temperature that the formation of irreversible siloxane bonds between the particles is prevented or reduced to a minimum.

The rate of formation of siloxane bonds between the particles increases with pH, ie with increasing concentration of hydroxyl ions, and with temperature.

Water and alcohol, e.g. methanol or ethanol, must therefore be removed at the lowest possible pH, preferably at the zero point charge, which is about 2.0 for colloidal silicic acid, and at moderate temperatures, preferably not higher than about 75 ° C. Using vacuum, water and alcohol, e.g. methanol or ethanol, evaporates rapidly even at temperatures below 50 ° C.

Low pH and low electrolyte contents prevent or minimize destabilization, caused by the formation of siloxane bonds between particles or aggregation of particles, of the silylated sol during the drying step, i.e. the removal of the liquid phase, which consists of water and / or alcohol, from the sun. To achieve maximum stability during the drying step, the silylated sol is treated with anion and cation exchange resin so that virtually complete deionization is achieved. The industry is well aware of methods for achieving such deionization. Suitable methods for deionization are described in U.S. Pat. Patent 2,577,485. As the 529,440 IS anion exchange resin, a strongly basic resin in the hydroxyl form can be used, and as the cation exchange resin, a strongly acidic resin in the hydrogen form can be used. Silylated sol can first pass through a column of cation exchange resin in the hydrogen form and then through a column of anion exchange resin in the hydroxyl form or, alternatively, through a column of the mixed resins.

The ion exchange cycle can be repeated two or more times if necessary.

Another alternative is to stir the silylated sun with a mixture of anchovy and cation exchange resin.

After the silylated silica particles have been dried to constant weight, the cake or lumps of particles are ground to a fine powder, for example in a ball mill. Organic compounds - liquid or molten form Organic compounds such as polyols, isocyanates or carboxylic acids, which may be liquids or solids room temperature, is used in the production of many kinds of polymers, e.g. polyurethanes, polyesters and polyamides.

The powder of silylated silicic acid particles of the present invention can be readily dispersed in such organic compounds by methods well known in the art.

Polyols Polyols used in the present invention to make polyurethanes, including urethane-based thermoelastics, are organic compounds that contain two or more hydroxyl groups.

The term polyol is used for low molecular weight compounds containing two or more hydroxyl groups, e.g. ethylene glycol (1,2-ethanediol) and glycerol (1,2,3-propanediol) as well as for polymeric compounds containing end hydroxyl groups, e.g. polyester polyols and polyether polyols with molecular weights up to several thousand.

Polyols can be divided into two classes; those used to make rigid foams, rigid solid materials and hard 529 440 IH coatings and having a molecular weight in the range 400-1000 and a functionality between 3 ch 8, and those used for making flexible foams and elastomers and having a molecular weight in the range 1000-6500 and functionality 2-3.

Polyols used in the present invention are of the polyether type, polyester type or are based on acrylics.

The molecular weights of the polyester and polyether polyols used in this invention can span low values, corresponding to monomer-type diols and triols, and high values of several thousand.

Polyols used to make nanocomposites of the present invention are commercial products sold under various trade names, e.g. Arcol from Lyondell, Caradol from Shell, Voranol from Dow, Daltolac from Huntsman, Baycoll and Desmophen from Bayer, and Lupranol from BASF.

Polyether polyols Polytetramethylene glycol polyols, PTMEG, produced by acid-catalyzed polymerization of tetrahydrofuran, THF, polypropylene glycol polyols, which can be based only on polypropylene oxide, a mixture of ethylene oxide and propylene oxide or a mixture of propylene oxide, ethylene oxide and polymetallic molybdenum , which are not really polyols but polyamines, are the four main types of polyether polyols used to make polyurethane polymers.

Polyester polyols Polybutanediol adipates, polycaprolactone polyols and polyethylene terephthalate polyols are three important types of polyester polyols. Polyester polyols can be linear or branched and the branching can be weak, moderate or extensive. Polyester polyols can be modified by incorporating low molecular weight saturated fatty acids into their structure.

Acrylic polyols Acrylic polyols are made by polymerizing hydroxyl-containing monomers such as hydroxyethyl methacrylate, 529 440 IS 'hydroxypropyl methacrylate allyl alcohol propoxylate copolymers. such as methyl methacrylate, styrene and butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, methacrylic acid acrylonitrile.

Polyester and polyether polyols are characterized by their hydroxyl functionality, which is related to the average hydroxyl groups per polyol and usually falls in the range from about 2 to almost 4. Acrylic polyols have functionalities from 2 to 8.

Diol-type polyols used in the present invention to make e.g. ester-based thermoelastics, are acyclic and alicyclic dihydroxy compounds. Preferred are diols having 2 to 15 carbon atoms such as ethylene, propylene, tetramethylene, pentamethylene, 2,2'-dimethyltrimethylene, hexemethylene, and decamethylene glycols, dihydroxycyclohexane, cyclohexane dimethanol, etc. Alphathates are particularly preferred. diols containing 2-8 carbon atoms. Corresponding ester-forming derivatives of diols are also valuable, ethylene oxide or ethylene carbonate can e.g. used instead of ethylene glycol.

Other polyols Castor oil, polycarbonate and polybutadiene polyols are other, less commonly used polyols.

The silicic acid powder of the present invention can be readily dispersed in the polyols described herein by methods well known in the art.

ISOCYêIIaÉGI 'The second main type of chemicals used in the commercial production of polyurethanes, including urethane-based thermoelastics, are polyisocyanates, especially diisocyanates. The two main types of diisocyanates are toluene diisocyanates, TDI, and methylenebis (phenyl isocyanates), MDI.

In addition to MDI, HDI, hexamethylene diisocyanate, IDPE, isoprene diisocyanate, and NDI, naphthalene diisocyanate, were used to form hard segments in urethane-based thermoelastics. 529 440 lß Diisocyanates and isocyanates used in the production of polyurethanes, including urethane-based thermoelastics, are commercial products sold under various trade names by e.g. Huntsman, Shell, Bayer, and BASF, Rhodia, and Dow.

Diisocyanates react with and are added to each chemical compound with active hydrogen, e.g. the hydrogen atoms on the hydroxyl groups in polyols and water, on the hydroxyl groups on the surface of silylated silicic acid particles or on the amine groups in primary and secondary amines.

The silicic acid powder of the present invention can be readily dispersed in the isocyanates described herein and in other isocyanates by methods well known in the art. The isocyanates then chemically modify the particle surface by reacting with surface silanol groups. The resulting particles have a chemically active surface that can react with polyols, isocyanates and other components in formulations to make polyurethanes, polyesters and polyamides.

Carboxylic acids Dicarboxylic acids of both aliphatic and aromatic types were used to prepare polyamides and polyesters, including amide and ester based thermoelastics.

Aliphatic carboxylic acids, as the term is used herein, refer to carboxylic acids having two carboxyl groups each attached to a saturated carbon atom. If the carbon atom to which the carboxyl group is attached is saturated and in a ring the acid is called cycloaliphatic. Aliphatic or cycloaliphatic acids having conjugated unsaturation generally cannot be used because they homopolymerize. Some unsaturated acids, such as maleic acids, may be used.

Representative aliphatic and cycloaliphatic acids that can be used in this invention to make amide and ester based thermoelastics are tallow acid, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, glutaric acid, succinic acid, carboxylic acid, oxalic acid, azelaic acid, allylmalonic acid, 4-cyclohexene-1,2-dicarboxylic acid, 2-ethylsuberic acid, 2,2,3,3-tetramethylsuccinic acid, cyclopentanedicarboxylic acid, decahydro- 529 440 I? 1,5-naphthalinedicarboxylic acid, 4'-bicyclohexyldicarboxylic acid decahydro-2,6-naphthalene dicarboxylic acid, 4,4 "-methylenebis (cyclohexanecarboxylic acid), 3,4'-fura-dicarboxylic acid, and 1,1'-cyclobutanedicarboxylic acid. Preferred aliphatic acids are cyclohexanedicarboxylic acids and adipic acid.

Aromatic dicarboxylic acids, As used herein, dicarboxylic acids having two carboxyl groups attached to a carbon atom in an isolated gasoline ring or fused rings.

It is not necessary that the two carboxyl groups be bonded to the same aromatic ring and in the case of several rings they may be joined by aliphatic or aromatic radicals or such radicals as ~ O- or ~ SO2-.

Representative aromatic dicarboxylic acids that can be used to make amide and ester based thermoelastics of this invention include terephthalic acid, phthalic acid and isophthalic acid, bibenzoic acid, substituted dicarboxy compounds with two benzene nuclei such as bis (p-carboxyphenyl) methane, p-oxy (p-carboxyphenyl) acid , ethylene-bis (p-oxybenzoic acid), 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, phenanthrene dicarboxylic acid, anthracene dicarboxylic acid, 4,4'-sulfonyl dibenzoic acid, and C1-C1-alkyl substituents , as halo, alkoxy, and aryl derivatives. Hydroxyl acids such as p (β-hydroxyethoxy) benzoic acid can also be used if an aromatic dicarboxylic acid is also present. Aromatic dicarboxylic acids are preferred in the preparation of ester-based thermoelastics in this invention. Of the aromatic acids, those having 8-16 carbon atoms are preferred, especially phenylene carboxylic acids, i.e. terephthalic, phthalic and isophthalic acids.

The silicic acid powder of the present invention can be readily dispersed in the carboxylic acids described herein by methods well known in the art.

Chain extenders, branchers and crosslinkers Chain extenders, branchers and crosslinkers are compounds present in fairly small amounts, less than 10% by weight and often less than 5% by weight, in formulations for making polyurethanes, including urethane-based thermoelastics, 529 440 IS ester-based thermoelastics and amide-based thermoelastics, in order to modify the properties of these polymers.

Diols such as ethylenediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol, and diamines, such as 4,4 "- diaminodiphenylmethane, 3,3'-dichloro-4,4 ' -diaminodiphenylmethane, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 3,3'-dichlorobenzidine and p-phenylenebenzidine, were used as chain extenders in polyurethane polymers, including urethane-based thermoelastics, ester-based thermoelastics and amesterloids.

Triols such as glycerol, 1,1,1-trimethylolpropane, tris (2-hydroxyethyl) isocyanurate pentaerythritol, trimellitic acid, pyromellitic acid and polyethylene oxide and polypropylene oxide triols having molecular weights of 400-3000 were used as branchers or crosslinkers in polyurethane thermoplastic base polymers; thermoelaster.

The silicic acid powder of the present invention can be readily dispersed in the chain extenders, branchers or crosslinkers described herein by methods well known in the art.

Dispersion of Silylated Silica Powder in Organic Liquids Many kinds of stirring equipment can be used to mix the silicic acid powder of the present invention with organic compounds used to make various kinds of polymers. To ensure perfect dispersion, ie. dispersion of the powder down to the primers in the organic liquid, the equipment should be selected from the more efficient mixing machines, e.g. high speed mixer.

It is important to achieve complete deaeration of the dispersion as air bubbles can cause porosity in the final material. In the preparation of certain polymers, e.g. polyurethanes, it is also important to reduce the water content to below a certain critical value, e.g. 0.1 529 440 H% by weight. It is therefore often advantageous to carry out the whole mixing process in vacuo.

Polymers made of cdmonents containing well dispersed silica powder Polyurethanes The polymer chains in polyurethanes contain the urethane bond -NH-CO-O-_ The simplest and commercially best method for producing the urethane bond is the reaction of the urethane radical -N = C = O, in eg diisocyanates, with a hydroxyl radical in e.g. polyols. The simplest form of a polyurethane polymer is the linear one where the polyol and the isocyanate each have the functionality 2. Linear polyurethanes are used as thermoplastics, e.g. and fiber.

By incorporating materials with functionality greater than 2, polymers can be prepared with varying degrees of crosslinking; from a few to many links. In this way you can make polyurethanes whose properties vary from soft elastomers to rigid, thermosetting resins that are reminiscent of the properties of phenolic resins. The properties of polyurethanes can be further modified by varying the ratio of polyol, which stands for the soft segments, to isocyanate, which stands for the hard segments of the polymer, in the formulation. Higher ratio, ratio, gives softer, more flexible materials because the tensile strength and modulus decrease while the elongation at break The unusual effect of the powder of the present invention to simultaneously increase the tensile strength and elongation at break for polyurethanes is particularly marked at higher ratio of polyol to isocyanate; i.e. Polyurethanes in which the soft block blocks, consisting of polyesters or polyethers, dominate the hard block blocks, consisting of polyisocyanates and chain extenders.

The great diversity of structures in polyurethanes explains the huge variation in physical properties, which makes polyurethanes the group of polymers with the widest range of applications, e.g. as thermoplastics, elastomers 529 440 io and thermosetting plastics, and in the manufacture of soft and rigid foams, fibers, coatings and adhesives.

Urethane-based thermoelastomers Urethane-based thermoelastomers are made by reacting a diisocyanate with a short-chain diol, e.g. 1,4-butanediol, and a long chain diol. The hard segment of the thermoelastomer is formed when the isocyanate reacts with the short-chain diol, which acts as a chain extender. The soft segment of the thermoelastomer is formed when the long chain diol reacts with the isocyanate.

Urethane-based thermoelastics are usually made by reacting the ingredients at temperatures above 80 ° C. The reaction can be carried out in different ways. In the so-called "one-shot" method, all the ingredients are mixed together. In the "prepolymer" method, the polyol is first reacted with the isocyanate to an isocyanate-containing prepolymer, which is then reacted with the chain extender, i.e. a low molecular weight polyol The silicic acid powder of the present invention can be readily incorporated into polyurethanes by dispersing the powder well in one, several or all of the components used in polyurethane manufacturing to give nanocomposites of polyurethanes with superior mechanical properties. and the elongation at break for - polyurethanes is particularly marked at high ratios of polyol to isocyanate; i.e. polyurethanes in which the soft block blocks, consisting of polyesters or polyethers, dominate over the hard block blocks, consisting of polyisocyanates and chain extenders.

In nanocomposites of polyurethane according to the present invention, therefore, the dependence of the polymer properties on the ratio between hard segments and soft segments decreases so that it becomes possible to combine high tensile strength with e.g. high impact strength and excellent low temperature properties. 529 440 ll Ester-based thermoelastics Like urethane-based thermoelastics, ester-based thermoelastics form 2-phase structures consisting of crystalline and amorphous regions, domains. The hard phase in crystalline domains usually consists of lamellar packed segments of polybutylene terephthalate, which form crystallites with melting points as high as 220 ° C. The soft, flexible phase of amorphous domains consists of polybutylene glycol ether, which has a glass transition temperature of -50 ° C when the number of monomer units in the ether is 12-16.

Ester-based thermoelastics can be made by ester exchange of a long chain polyol and a short chain polyol with the methyl ester of a dicarboxylic acid. The polymerization is carried out in the presence of an alkyl titanate, e.g. butyl titanate, and often in combination with alkaline earth metal acetate. The short-chain polyol is in excess and when it is evaporated, the product is driven towards high molecular weight. An ester prepolymer is usually first formed by heating the catalyzed mixture to about 200 ° C while methanol is removed by distillation. The ester prepolymer is driven towards high molecular weight by evaporation of the excess polyol under vacuum, <1 mm Hg, and at temperatures between 240 ° C and 250 ° C.

Ester-based thermoelastics contain the ester linkage -CO-O-.

The silicic acid powder of the present invention can be easily incorporated into ester-based thermoelastics by dispersing the powder well in one, several or all of the components used in the manufacture of ester-based thermoelastics to give nanocomposites of ester-based thermoelastics with superior mechanical properties. and the elongation at break for ester-based thermoelastics is particularly marked at high ratios of polyol to isocyanate; i.e. ester-based thermoelastics in which the soft segment blocks, consisting of e.g. 529 440 22. polybutylene glycol, dominates over the hard block blocks, consisting of eg polybutylene terephthalate.

In nanocomposites of ester-based thermoelastics according to the present invention, therefore, the dependence of the polymer properties on the ratio between hard segments and soft segments decreases so that it becomes possible to combine high tensile strength with e.g. high impact strength and excellent low temperature properties.

Amide-based thermoelastics Amide-based thermoelastics are also 2-phase structures consisting of crystalline and amorphous regions, domains.

The hard phase of crystalline domains consists of polyamide II and polyamide 12 but may also contain segments of polyamide 6, polyamide 66 or copolymers of polyamide 6 and polyamide 11.

The soft, flexible phase of amorphous domains is usually poly (tetramethylene oxide) glycol, but may also be polyethylene glycol or polypropylene glycol.

The three major types of amide-based thermoelastics are called polyesteramides (PEA), polyetheresteramides (PEEA), and polycarbonate esteramides (PCEA).

The amide group is formed during the polymerization of the monomer to PEA, PEEA and PCEA. Polyamides are typically synthesized by condensation reactions of either diamines with dicarboxylic acids or by ring-opening polymerization of cyclic lactams.

PEA, PEEA, and PCEA elastomers are synthesized by condensing the aromatic diisocyanate MDI with aliphatic dicarboxylic acids and a polyether or polyester prepolymer having a molecular weight of 500 to 5000 and terminated with aliphatic carboxylic acid.

The polymerization is usually carried out in homogeneous phase in a polar solvent which does not react with isocyanates at elevated temperatures (200 ° C to 280 ° C) by controlled addition of the disocyanate to the solution of the other monomers. The added dicarboxylic acid serves as a chain extender for the hard segments and forms semi-aromatic hard segments with MDI. It is analogous to the 1,4-butanediol used in 529 440 2.3 to increase the length of urethane blocks in urethane - based thermoelastics. Polyester, polyether or polycarbonate prepolymers terminated with aliphatic carboxylic acids form the soft segments of PEA, PEEA, AND PCEA. These prepolymers are obtained by esterification reactions of dihydroxyl-terminated polyols with an excess of aliphatic carboxylic acid or directly by reaction of a short chain diol with an excess of a carboxylic acid.

Amide-based thermoelastics can be made by reacting a low molecular weight polyamide, such as low molecular weight polyamide 6, polyamide 66 or copolymers of polyamide 6 and polyamide II, with excess dicarboxylic acid at 230 ° C and high pressure,> 2.5 MPa. The polyamide is then reacted with a polyester at 230-280 ° C under vacuum and in the presence of a titanate catalyst.

Amide-based thermoelastics contain the amide linkage -NH-CO-.

The silicic acid powder of the present invention can be easily incorporated into amide-based thermoelastics by dispersing the powder well in one, several or all of the components used in the manufacture of amide-based thermoelastics to give nanocomposites of amide-based thermoelastics with superior mechanical properties. and the elongation at break for amide-based thermoelastics is particularly marked for amide-based thermoelastics, in which the soft block blocks, consisting of e.g. poly (tetramethylene oxide) glycol, dominates over the hard block blocks consisting of e.g. polyamide ll or polyamidl2 12.

In nanocomposites of according to the present invention, therefore, the dependence of the polymer properties on the ratio between hard segments and soft segments decreases so that it becomes possible to combine high tensile strength with e.g. high impact strength and excellent low temperature properties.

Dispersion of silicic acid powders in thermoplastics by combating or "master batching" 529 440 2% Compounding is a process of adding various additives, such as silicic acid powders according to the present invention, to thermoplastics. mixed with the additives in question, eg the silicic acid powder according to the present invention, in an extruder.The polymer melt is extruded and when it cools it is chopped into pellets which can then be used directly by the plastic processor.Masterbatching is a related process in which high levels of additives, t. ex silica powder according to the present invention, is dispersed in a carrier medium, usually a thermoplastic, which can then be used in small amounts directly by the plastic processor to pigment or modify various polymeric materials.

The invention is described in more detail in the following exemplary embodiments.

Examples A. Methods for making silicic acid powder dispersible in polyols, isocyanates, carboxylic acids and other compounds for making polyurethanes, including urethane-based thermoelastics, ester-based thermoelastics, amide-based thermoelastics and thermoplastics.

Example A1.

To 360 g of alkali-stabilized silica sol with a particle size of 10 .mu.m and a content of 50% SiO2 (Nyacol 9950 from Eka Nobel), was added 320 g of methanol. The pH of the methanolic sol was 9.75. 7.2 g of dimethyldimethoxysilane (silane Z-6194 from Dow Corning) was dissolved in 200 g of methanol. The silane solution was added to the diluted sol at a rate of 14 g per hour.

The temperature of the diluted sol was maintained at 27 ° C during the addition of the silane solution. After complete addition, the silylated sol was stirred for 3 hours at 27 ° C. The silylated sol of pH 10.74 was deionized to pH 2.91 by adding a mixture of 74 g of strong cation exchange resin 22 g of strong anion exchange resin. 841 g of deionized, silylated sol was recovered in 529,440 ice and dried by removing the liquid phase consisting of a mixture of methanol and water under vacuum and a temperature not exceeding 10 ° C. 188 g of dry silylated sol was recovered. The dried silylated sol was ground in a ball mill to a fine powder which was easily dispersed in polyols and isocyanates to a clear dispersion.

Example A2 As in Example 1 but the dried silylated sol was ground in a mortar to a fine powder which was easily dispersed in polyols and isocyanates to a clear dispersion.

Example A3 As in Example 1 but the deionized, silylated silica sol was dried by evaporating the liquid phase in the air stream from a fan at 8 ° C. The dried silylated sol was ground in a mortar to a fine powder which was easily dispersed in polyols and isocyanates to a clear dispersion.

Example A4 As in Example 1 but the silane used was methyltrimethoxysilane (silane Z-6070 from Dow Corning).

Example A5 As in Example 1 but use silane was trimethylmethoxysilane Example A6 As in Example 1 but use silane was isobutyltrimethoxysilane (silane Z-2306 from Dow Corning).

Example A7 As in Example 1 but the silane used was n-octyltriethoxysilane (silane Z-6341 from Dow Corning). 529 440 lb Example A8 As in Example 1 but the silane used was aminoethylaminopropyltrimethoxysilane (silane Z-6020 from Dow Corning).

Example A10 As in Example 1 but the silane used was aminopropyltriethoxysilane (silane Z-6011 from Dow Corning).

Example All As in Example 1 but the silane used was vinyltrimethoxysilane (silane Z-6300 from Dow Corning).

Example A12 As in Example 1 but the silane used was 3-glycidoxypropyltrimethoxysilane (silane Z-6040 from Dow Corning).

Example A13 As in Example 1 but the silane used was 3-methacryloxypropyltrimethoxysilane (silane Z-6030 from Dow Corning).

Example A14 150 g of alkali stabilized silicic acid sol with a particle size of 100 nm and a content of 50% SiO2, was diluted to 12% SiO2 with 475 g of water and deionized to pH 3.5 with strong cation exchange resin. 2.25 g of dimethyldimethoxsilane (silane Z-6194 from Dow Corning) was dissolved in 110 g of methanol and partially hydrolyzed by the addition of 0.23 g of water. The silane solution was added to the diluted sol at a rate of 28 g per hour.

The diluted solar temperature was maintained at 25 ° C during the addition of the silane solution. After complete addition, the silylated sol was stirred for 1 hour at 25 ° C. The silylated sol was poured onto two baking trays and the liquid phase consisting of methanol and water was evaporated in the air streams from two fans at 25 ° C. 77 g of dry, silylated was recovered which was ground to a fine powder in a ball mill. The ground powder was easily dispersed in polyols and isocyanates to a clear dispersion. 529 440 2.? Example A15 75 g of alkali stabilized silicic acid sol having a particle size of 100 nm and a content of 50% SiO2, was diluted to 12% Sif »with 238 g of water and deionized to pH 3.5 with strong cation exchange resin. 1.50 g of dimethyl dimethoxysilane (silane Z-6194 from Dow Corning) was dissolved in 50 g of methanol. The silane solution was added to the diluted sun at a rate of 21 g per hour.

The diluted solar temperature was maintained at 35 ° C during the addition of the silane solution. After complete addition, the silylated sol was stirred for 1 hour at 25 ° C. The silylated sol was poured onto a baking tray and the liquid phase consisting of methanol and water was evaporated in an oven with air circulation at 75 ° C. 39 g of dry, silylated was recovered which was ground to a fine powder in a mortar. The ground powder was easily dispersed in polyols and isocyanates to a clear dispersion.

Example A16 To 200 g of alkali-stabilized silicic acid sol with a particle size of 22 nm and a content of 40% SiO2, 200 g of methanol was added. The pH of the methanolic sol was 9.75. 6.24 g of dimethyldimethoxysilane (silane Z-6194 from Dow) was dissolved in 225 g of methanol. The silane solution was added to the diluted sol at a rate of 10 g per hour. The temperature of the diluted sol was maintained at 25 ° C during the addition of the silane solution. After complete addition, the silylated sol was stirred for 3 hours at 25 ° C.

The silylated sol of pH 10.74 was deionized to pH 2.91 by adding a mixture of 88 g of strong ion exchange resin and 26 g of strong ion exchange resin. 592 g of deionized, silylated sol were recovered and dried by pouring the sun onto two baking trays and evaporating the liquid phase consisting of methanol and water in the air streams from two fans at a temperature not exceeding 10 ° C. 80 g of dry, silylated sol was recovered which was ground to a fine powder in a mortar. The ground powder was easily dispersed in polyols and isocyanates to a clear dispersion.

Example A17 529 440 28 To 267 g of alkali-stabilized silicic acid sol with a particle size of 12 nm and a content of 30% SiO2, 133 g of methanol were added.

The pH of the methanolic sol was 9.86. 12.2 g of dimethyldimethoxysilane (silane Z-6194 from Dow) was dissolved in 300 g of methanol. The silane solution was added to the diluted sol at a rate of 14 g per hour. The temperature of the diluted sol was maintained at 25 ° C during the addition of the silane solution. After complete addition, the silylated sol was stirred for 3 hours at 25 ° C.

The silylated sol of pH 10.81 was deionized to pH 2.95 by adding a mixture of 100 g of strong ion exchange resin and 30 g of strong ion exchange resin. 670 g of deionized, silylated sol were recovered and dried by pouring the sol on two baking trays and evaporating the liquid phase consisting of methanol and water in vacuo at a temperature not higher than 10 ° C. 80 g of dry, silylated sol was recovered which was ground to a fine powder in a ball mill. The ground powder was easily dispersed in polyols and isocyanates to a clear dispersion.

Example A18 80 g of alkali stabilized silicic acid sol with a particle size of 100 nm and a content of 50% SiO2 was diluted to 9.3% SiO2 with 350 g of methanol. The methanolic sol of pH 10.51 was deionized to pH 2.98 with a mixture of 31 g of strong cation exchange resin and 14 g of strong anion exchange resin. 408 g of deionized methanolic sol were recovered and dried by pouring the sol on two baking trays and evaporating the liquid phase consisting of methanol and water in the air streams from two fans at 25 ° C. The dry was ground to a fine powder in a mortar. The ground powder was dispersed in polyols and isocyanates to a cloudy dispersion.

Example A19 80 g of alkali stabilized silicic acid sol with a particle size of 10 .mu.m and a content of 50% of SiO2 were diluted to 9.3% of SiO2 with 350 g of methanol. The methanolic sol of pH 9.75 was dried by pouring 529,440 9.9 of the sol on two baking trays and the liquid phase consisting of methanol and water was evaporated in the air streams from two fans at 25 ° C. The dry sun was ground to a fine powder in a mortar. The ground powder was dispersed in polyols and isocyanates to a cloudy dispersion.

B. Mechanical properties of polyurethanes reinforced with small silicic acid particles.

Preparation of samples for mechanical testing was performed according to the methods commonly used in the polyurethane industry.

The raw materials used to make the polymeric materials are defined in Table 4.

The diisocyanate is added to a well-mixed and homogeneous mixture of the polyol, with or without silicic acid particles, and the other ingredients in formulations to make polyurethanes. The formulation was poured into a mold and reacted and cured to a 150x150x5 mm plate. The mechanical properties of the polyurethane were measured for dog bone shaped plates which were punched out of these plates. The measurements were made according to the methods commonly used to test polyurethanes.

Stress-strain measurements were made with a MECMESIN AFC-M 2500N tensile tester.

Breaking strength is given in Table 3 in MPa. The elongation at break is stated as% of the original length of the sample. The composition of the polymer samples made in the patent examples is also given in the table. The polyols and isocyanates are designated by abbreviated trade names as explained in Table 4. MDI refers to the isocyanate used in a special preparation and the number designations are explained in Table 4. The mixing ratio is polyol zisocyanate - the weight ratio. BDO and OH-containing organic solvents (eg for the catalyst) and dispersants (eg for the zeolite) are included in the amount of polyol. The left column of Table 5 shows a typical formulation for a reference PUR, Example B13, and the right column shows the formulation for a PUR containing 10.8% particles, Example B14. Index is given the value 100 when polyol 529 440 (including BDO, dispersants and OH-containing solvents) and isocyanate are present in stoichiometric amounts; systems with indices below and above 100 are sub- and over-crosslinked, respectively.

The size and content of silicic acid particles are also given in the table.

The results in Table 3 show that nanocomposites of polyurethanes, made of many different polyols and isocyanates, and small particles of silicic acid from a powder according to the present invention have improved tensile strength in combination with unchanged or increased elongation at break, which leads to markedly large improvements in fracture energy. The greatest improvements in tensile strength, elongation at break and breaking energy were obtained with high molecular weight polyols. Unexpected was that the degree of improvement went through a maximum with increasing content of silicic acid and that in some systems the maximum was achieved at surprisingly low levels of silicic acid.

Example B1 Polyurethane reference tests were performed on Arcol 1004 and Suprasec 5025 with index 90.

Example B2 Polyurethane was made from Arcol 1004 containing 16.0% by weight of powder from Example A17 and Suprasec 5025 with index 90.

The finished polyurethane contained 10.8% by weight of SiO2.

Examples B3a-c Reference tests of polyurethane were performed by Voranol 4711 and Suprasec 2018 with indices 90, 105 and 120.

Example B4 Polyurethane was made from Voranol 4711 containing 16.0% by weight of powder from Example A17 and Suprasec 5025 with index 90.

The finished polyurethane contained 10.8% by weight of SiO2.

Examples B5a-c Polyurethane was made from Voranol 4711 containing 8.0% by weight of powder from Example A17 and Suprasec 5025 with indexes 90, 105 and 120. The finished polyurethane contained 5.4% by weight of SiO2. 529 440 3> \ Examples B6a-c Reference tests of polyurethane were performed by Caradol 28-02 and Suprasec 2018 with indexes 90, 105 and 120.

Example B7 Polyurethane was made from Caradol 28-02 containing 8.0% by weight of powder from Example A17 and Suprasec 2018 with index 120.

The finished polyurethane contained 5.4% by weight of SiO2.

Example B8 As in Example B7 but the polyol contained 16.0% by weight of powder from Example A17 and the index was 105. The finished polymer contained 10.8% by weight of SiO2.

Example B9a ~ c Polyurethane was made from Caradol 28-02 containing 16.0% by weight of powder from Example A16 and Suprasec 2018 with index 90, 105 and 120. The finished polyurethane contained 10.8% by weight of SiO2.

Examples B10a-c As in Example B9a-b but the polyol contained 5.4% by weight of powder from Example A16.

Examples B1a-c Polyurethane was made from Caradol 28-02 containing 16.0% by weight of powder from Examples A3 and Suprasec 2018 with indices 90, 105 and 120. The finished polyurethane contained 10.8% by weight of SiO2.

Examples B12a-c As in Example B1a-b but the polyol contained 5.4% by weight of powder from Example A3.

Example B13 Reference test of polyurethane was done by Voranol 4711 and Suprasec 2018 with index 105. 529 440 31 Example B14 Polyurethane was made by Voranol 4711 containing 16.0% by weight of powder from Example A 14 and Suprasec 2018 with index 105.

The finished polyurethane contained 10.8% by weight of SiO2.

Example B15 Polyurethane was made from Voranol 4711 containing 16.0% by weight of powder from Example A15 and Suprasec 2018 with index 105.

The finished polyurethane contained 10.8% by weight of SiO2.

Example B16 Reference tests of polyurethane were performed by Lupranol 2090 and Lupranate 134-7 with index 105.

Example B17 Polyurethane was made from Lupranol 2090 containing 16.0% by weight of powder from Example A3, and Lupranate 134-7 with index 105. The finished polyurethane contained 10.8% by weight of SiO2.

Example B18 Reference tests of polyurethane were performed by Lupranol 2090 and Lupranate 134 ~ 7 with index 105.

Example B19 Polyurethane was made from Lupranol 2090 containing 8.0% by weight of powder from Example A16, and Lupranate 134-7 with index 105.

The finished polyurethane contained 5.9% by weight of SiO2.

Example B20 Reference tests of polyurethane were performed by Lupranol 2090 and Lupranate 134-7 with index 105.

Example B21 Polyurethane was made from Lupranol 2090 and Lupranate 134-7 containing 10.0% by weight of powder from Example A3 with index 105.

The finished polyurethane contained 2.1% by weight of SiO2. 529 440 33 Example B22 Reference tests of polyurethane were performed by PTHF 1000 and Lupranate 134-7 with index 105.

Example B23 Polyurethane was made from PTHF 1000 and PTHF 1000 containing 15.0% by weight of powder from Example A3 and Lupranate 134-7 with index 105. The finished polyurethane contained 3.2% by weight of SiO2.

Example B24 Reference tests of polyurethane were performed by PTHF 1000 and METV with index 105.

Example B25 Polyurethane was made from PTHF 1000 and MET containing 15.0% by weight of powder from Example A3 and Lupranate 134-7 with index 105.

Finished polyurethane contained 4.7% by weight of SiO2.

Example B26 Reference tests of polyurethane were performed by PTHF 2000 and Lupranate 134-7 with index 105.

Example B27 Polyurethane was made from PTHF 2000 and PTHF 2000 containing 15.0% by weight of powder from Example A3 and Lupranate 134-7 with index 105. The finished polyurethane contained 5.1% by weight of SiO2.

Example B28 Reference tests of polyurethane were performed by Lupranol 2090 and Suprasec 2018 with index 105.

Example B29 Polyurethane was made from Lupranol 2090 containing 16.0% by weight of powder from Example A18, and Suprasec 2018 with index 105. The finished polyurethane contained 10.8% by weight of SiO2. 529 440 3% Example B30 Polyurethane was made from Lupranol 2090 containing 16.0% by weight of powder from Example A19, and Suprasec 2018 with index 105. Finished polyurethane contained 10.8% by weight of SiO2.

Claims (23)

529 440 Requirements: S5 A process for making particles of silicic acid in the form of a powder comprising the following steps: 1) An alkali-stabilized sol with a particle size in the range from 8 to 250 nm is diluted to a maximum of 30% SiO 2 with water and / or water-soluble organic solvent. 2) A silane is pumped into the sun in step 1 which is kept at a temperature between 20 and 75 ° C, 3) The sun in step 2 is deionized by contacting it with anion and cation exchange resins. 4) The silylated, deionized sun in step 3 is dried by evaporating the water, preferably in a vacuum or in a stream of air. 5). The dried sun in step 4 can be ground to a fine powder. wherein at least two of the steps 2), 3) and 4) can be performed in a different order. A process according to claim 1 wherein the silane is used in a mixture with water and / or a water-soluble solvent. A process according to claim 1 or 2 wherein the silane is dissolved in a lower aliphatic alcohol. A process according to any one of claims 1 to 3 wherein the pH of the diluted sun in steps is between 8.0 and 10.5. A process according to any one of claims 1 to 4 wherein the pH in step 3 is below 10.0. A process according to any one of claims 1 to 5 wherein the silane in step 2 has the general formula RSiX3 and wherein R is a non-hydrolysable group which may be organoreactive or non-organoreactive and X is a methoxy or ethoxy group. 529 440 Bb A process according to any one of claims 1 to 5 wherein the silane in step 2 has the general formula R 2 SiX 3 and wherein R is a non-hydrolysable group which may be organoreactive or non-organoreactive and X is a methoxy or ethoxy group. A process according to any one of claims 1 to 5 wherein the silane in step 2 has the general formula R 3 SiX and wherein R is a non-hydrolysable group which may be organoreactive or non-organoreactive and X is a methoxy or ethoxy group. Silica powder which can be made according to a process according to any one of claims 1 to 8. Silica powder according to claim 9, comprising amorphous, dense, substantially non-aggregated silicon spheres with a diameter of 8 ~ 250 nm. A method of preparing a polymeric material comprising reacting a) a first component with b) a second component and optionally second components characterized in that said first component is a polyol, said second component is an isocyanate, dicarboxylic acid or a amine and that c) small particles of silicic acid from a dispersible silicic acid powder according to any one of claims 9 to 10 are mixed into at least one of said components before the reaction. A method according to claim 11 in which the polymeric material is polyurethane, comprising urethane-based thermoelastics. A method according to claim 11 in which the polymeric material is polyester, comprising ester-based thermoelastics. A method according to claim 11 in which the polymeric material is polyamide, comprising amide-based thermoelastics. A method according to any one of claims 11 to 14, wherein said small particles of silicic acid constitute up to 25% of said polymeric material. " A method according to any one of claims 11 to 15, wherein said polymeric material is selected from the group consisting of urethane-based polymers, comprising urethane-based thermoelastics, and polyurea polymers containing urethane groups. A method according to any one of claims 11 - 16 wherein said other components are chain extenders, branchers, crosslinkers, catalysts, foaming agents and / or defoamers. A polymeric material which can be made by a method according to any one of claims 11 - 17. 529 440 5-1- 19. l9. A method of making a thermoplastic which comprises incorporating the powder according to any one of claims 9 to 10 into the narrow polymer, preferably in an extruder. Use of the silicic acid powder according to any one of claims 9-10 as a filler in the production of polymeric materials. Use of the silicic acid powder according to any one of claims 9-10 as a filler in liquid lubricants, fuels and waxes. Use of a polymeric material according to claim 18 for the production of flexible and rigid foams, fibers, coatings and cast elastomers. Uses according to claim 22, wherein the polymeric material is a polyurethane material.