DE102006011226A1 - Preparation of aqueous silicone emulsion comprises mixing polyorganosiloxane containing a silicon unit, emulsifier, water and optionally an additive e.g. preservative or thickener, by agitation and homogenizing the obtained mixture - Google Patents

Abstract

Preparation of aqueous silicone emulsion (A) with an average volume particle size of 1-100 mu m comprises mixing polyorganosiloxane (100 parts by weight) containing a silicon unit (I), an emulsifier (1-30 parts by weight), water (25 parts by weight) and optionally an additive e.g. additional emulsifier, wetting agent, preservative, thickener, dye or aromatic material, by agitation and homogenizing the obtained mixture with a homogenizing system. Preparation of aqueous silicone emulsion (A) with an average volume particle size of 1-100 mu m comprises: mixing polyorganosiloxane (100 parts by weight) containing a silicon unit (I) of formula (Ra(R1>O)bSiO(4-a-b)/2), an emulsifier (1-30 parts by weight), water (25 parts by weight) and optionally an additive e.g. additional emulsifiers, wetting agents, preservatives, thickeners, dyes or aromatic materials, by agitation (where the peripheral velocity of the agitator is smaller than 5 m/s) and homogenizing the obtained mixture with a homogenizing system (where the mixture is led on an average of up to 2 times by the homogenator and the total energy entry, in the homogenator, is up to 200 kJ/kg). R : an univalent, optionally substituted 1-30C hydrocarbon or H (where up to 1 hydrogen atom is directly bound to a silicon atom); R1>H or an univalent, optionally substituted hydrocarbon; and either a, b : 0-3; or a+b : less than or equal to 3.

Description

The The invention relates to a process for the preparation of silicone emulsions, containing in particular highly viscous polyorganosiloxanes and a volume average Particle size of 1-100μm have.

silicones are diverse used. To the application and dosage especially with viscous products to facilitate it is for many applications desirable, that the organosilicon compounds in dilute form available. The use of organic solvents, such as benzene or Chlorinated hydrocarbons, for this purpose is possible, but from ecological and occupational health point of view. Therefore, the use is done mostly in the form of watery Emulsions or dispersions, usually as oil-in-water emulsions (O / W emulsions), which can be diluted with water are. As the oil phase become thereby the water-immiscible organosilicon ones Compounds understood, optionally dissolved in organic solvents.

For many applications, it is advantageous if the silicone has a high molecular weight and thus a high viscosity. A known way to arrive at emulsions containing a high molecular weight silicone is the emulsion polymerization of low molecular weight in particular cyclic organosiloxanes with arylalkylsulfonic acids, as described in DE-OS 1495512. By intensive stirring or homogenization with a high pressure homogenizer exceptionally fine particle sizes are achieved, which are no longer recognizable with an optical microscope. This procedure was later optimized by using linear oligomers instead of cyclic siloxanes. From these oligomers, a paste is formed in the presence of emulsifiers, condensation catalysts and a very small amount of water, in which the polymerization takes place. Subsequently, this paste is diluted to the desired concentration ( EP 93310 B2 ) Again, the fineness of the emulsion is emphasized.

It is believed that a particle size smaller than 300 nm is necessary to allow the emulsion polymerization and to obtain a stable emulsion ( US Pat. No. 6,245,852 B1 ). WO 9818434 describes the use of such finely divided emulsions with particle sizes in cosmetic compositions. High-viscosity silicones having a viscosity greater than 3 Pas can also be converted into emulsion form, for example, if the viscosity of the emulsifier phase is adjusted by adding thickeners to the viscosity of the oil phase, for example, so that the viscosity of the emulsifier phase is at least 10% of the viscosity of the oil phase ( EP 665861 B2 ). However, for some applications, eg in cosmetic preparations, coarser ponds are advantageous ( JP 4230309 A ). Particle sizes of 1-100 μm are achieved when highly viscous polysiloxanes are mixed successively with emulsifiers and portions with water ( EP 579458 B1 ). This procedure has the disadvantage that the dosage and handling of the highly viscous polysiloxane and the maintenance of the individual steps of the emulsifier and water addition are very expensive.

• (a) 100 Gewichtsteile Polyorganosiloxane enthaltend Einheiten der allgemeinen Formel R_a(R¹O)_bSiO_(4-a-b)/2 (I),worin R gleich oder verschieden sein kann und einen einwertigen, gegebenenfalls substituierten Kohlenwasserstoffrest mit 1 bis 30 Kohlenstoffatomen oder Wasserstoffatom bedeutet, wobei an ein Siliziumatom maximal 1 Wasserstoffatom direkt gebunden ist, R¹ gleich oder verschieden sein kann und Wasserstoffatom oder einen einwertigen, gegebenenfalls substituierten Kohlenwasserstoffrest bedeutet, a 0, 1, 2 oder 3 ist und b 0, 1, 2 oder 3 ist, mit der Maßgabe, dass die Summe a + b kleiner oder gleich 3 ist, bevorzugt im Durchschnitt einen Wert von 1,5 bis 2,4, besonders bevorzugt 1,8 bis 2,3, insbesondere von 1,9 bis 2,1, aufweist, und dass die Organopolysiloxane vorzugsweise aus 5 bis 50 000, bevorzugt aus 10 bis 10 000, besonders bevorzugt aus 20 bis 1000, Einheiten der Formel (I) bestehen,
• (b) 1 bis 30 Gewichtsteile eines Emulgators,
• (c) mindestens 25 Gewichtsteile, vorzugsweise mindestens 40 Gewichtsteile, Wasser und
• (d) ggf. weitere Zusätze wie z.B. zusätzliche Emulgatoren, Netzmittel, Konservierungsmittel, Verdicker, Farbstoffe oder Duftstoffe, durch R ühren vermischt werden, wobei die Umfangsgeschwindigkeit des Rührers kleiner als 5 m/s, vorzugsweise kleiner als 2 m/s, ist und in einem 2. Schritt die im 1. Schritt, erhaltene Mischung mit einer Homogenisiereinrichtung homogenisiert wird, wobei die Mischung durchschnittlich maximal 2 mal durch den Homogenisator geführt wird und der gesamte Energieeintrag beim Homogenisieren maximal 200 kJ/kg, vorzugsweise maximal 20 kJ/kg, beträgt.

The invention relates to a process for the preparation of aqueous silicone emulsions having a volume-average particle size of 1-100μm, characterized in that
in a first step

• (A) 100 parts by weight of polyorganosiloxanes containing units of the general formula R _a (R ¹ O) _b SiO _{(4-ab) / 2} (I), wherein R may be the same or different and is a monovalent, optionally substituted hydrocarbon radical having 1 to 30 carbon atoms or hydrogen atom, wherein to a silicon atom at most 1 hydrogen atom is directly bonded, R ^{1 may be the} same or different and is hydrogen atom or a monovalent, optionally substituted hydrocarbon radical a is 0, 1, 2 or 3 and b is 0, 1, 2 or 3, with the proviso that the sum a + b is less than or equal to 3, preferably a value of 1.5 to 2 on average, 4, more preferably 1.8 to 2.3, in particular from 1.9 to 2.1, and that the organopolysiloxanes preferably from 5 to 50,000, preferably from 10 to 10,000, more preferably from 20 to 1000, units of the formula (I) exist,
• (b) 1 to 30 parts by weight of an emulsifier,
• (C) at least 25 parts by weight, preferably at least 40 parts by weight, of water and
• (D) optionally further additives such as additional emulsifiers, wetting agents, preservatives, thickeners, dyes or fragrances are mixed by stirring, wherein the peripheral speed of the stirrer is less than 5 m / s, preferably less than 2 m / s, and in a second step, the mixture obtained in the first step, is homogenized with a homogenizer, the mixture is passed through the homogenizer on average a maximum of 2 times and the total energy input during homogenization a maximum of 200 kJ / kg, vorzugswei maximum 20 kJ / kg.

In a preferred embodiment the method according to the invention are as component (a) polyorganosiloxanes containing units of used in general formula (I), in which in average at least one unit, preferably in 1.5 to 2.5 units, of the formula (I) b is a value greater than or equal to 1.

The viscosity of the polyorganosiloxane (a) is preferably at least 10 times large, in particular at least 50 times as large as the viscosity of the mixture from emulsifier (b) and water (c).

Examples for leftovers R are hydrogen, unsubstituted, branched or unbranched Alkyl radicals, such as methyl, ethyl, propyl, isopropyl, hexyl, 2-ethylhexyl, Octyl or dodecyl radicals; substituted alkyl radicals, such as trifluoropropyl, Cyanoethyl, glycidoxypropyl, polyalkylene glycolpropyl, aminopropyl or Aminoethylaminopropylreste; unsaturated radicals, such as vinyl, methacryloxypropyl or allyl residues; aromatic radicals, such as phenyl, tooleyl, xylyl, naphthyl, Anthracyl or benzyl radicals.

Prefers when R is hydrocarbyl radicals of 1 to 18 Carbon atoms, more preferably the methyl or phenyl radical, in particular more than 80 mol% of the radicals R in the siloxane (a) have the meaning of methyl radicals.

Examples of radicals R ¹ are hydrogen atom, unsubstituted, branched or unbranched alkyl radicals, such as methyl, ethyl, propyl, isopropyl and butyl radicals.

Radical R ¹ is preferably hydrogen and hydrocarbon radicals having 1 to 4 carbon atoms, more preferably hydrogen.

The siloxanes (a) are preferably those of the formula R ¹ O [SiR ₂ -O] _c SiR ₂ -OR ¹ (II), where R and R ^{1 have} the abovementioned meanings and c has a value of from 5 to 50,000, preferably from 10 to 10,000, particularly preferably from 20 to 1,000.

The Polysiloxanes (a) from units of the formula (I) are commercially available products or can after known methods are produced.

When Emulsifiers (b) can in the process according to the invention all for now the preparation of silicone emulsions known emulsifiers used be such. nonionic, anionic or cationic emulsifiers.

Examples for emulsifiers (b) are polyethylene glycol ethers and esters of natural and / or synthetic alcohols or carboxylic acids having 8 to 24 carbon atoms and of natural Glycerides, polyethylene glycol ethers of alkylphenols, alkylpolyglycosides, Amine salts of fatty acids, Alkali sulfosuccinates and tetraalkylammonium halides, e.g. Cetyltrimethalammoniumchlorid, as well as surface-active Compounds that simultaneously acidic or basic catalysts could be.

Prefers become surface-active as emulsifier (b) Compounds used simultaneously acidic or basic catalysts are. Examples of such Emulsifiers (b) are phosphoric acid partial esters, Alkyl or alkylaryl sulfonic acids, acidic alkyl sulfates or tetraalkylammonium hydroxides. The use of such emulsifiers has the advantage that in the context of the method according to the invention the condensation of the polyorganosiloxane (a) takes place in the emulsion can. This optionally carried out condensation is preferably carried out until the desired Viscosity, preferably a viscosity greater than 100 Pas at 25 ° C, reached, what is the neutralization of the resulting emulsion followed. It may be necessary that the condensation step also after the Homogenisierschritt 2 until reaching the desired oil viscosity and the Neutralization is continued.

Especially Component (b) is preferably alkylarylsulfonic acids.

component (b) is used in the process according to the invention in amounts of preferably 2 to 10 parts by weight, per 100 parts by weight Polyorganosiloxane (a) used.

When Water (c) is preferably demineralized water, distilled or (repeatedly) redistilled water, water for medical or pharmaceutical purposes Purposes such as e.g. Purified water (Aqua purificata according to Pharm. Eur.).

The used according to the invention Water (c) preferably has a conductivity of less than 50 μS / cm, especially preferably less than 10 μS / cm, in particular less than 1.3 μS / cm.

In the method according to the invention preferably at least 40 parts by weight of water (c), per 100 parts by weight of polyorganosiloxane (a) are added. Preferably, the total amount of water that is required to adjust the desired solids content, already presented at the beginning of the process in the mixer. However, it is of course possible, the finished emulsion also later to dilute to the desired solids content.

When Component (d) can all known additives, the usual Be added to silicone emulsions, e.g. Preservation or Disinfectants, thickeners, protective colloids, corrosion inhibitors, Dyes or fragrances are added. The addition of this However, components may also be removed after a later process step, e.g. to the second step.

In the process according to the invention, preference is given to using thickener, particularly preferably anionic thickener, as component (d). In particular, these are linear vinyl polymers of the general formula R ³ - (CR ² ₂ -CR ² ₂ ) _n -R ³ (III), wherein R ^{3 may be the} same or different and represents hydrogen atom or the thermally or photochemically formed starting radicals of known radical initiators,
R ^{2 may be the} same or different and is hydrogen, C _1-30 hydrocarbon radicals, carboxyl groups or their salts, groups of the formula -C (O) -OR ⁴ (IV), Groups of the formula -C (O) -NR ⁴ ₂ (V), Groups of the formula -OC (O) -R ⁴ (VI), Groups of the formula -C (O) -OC (O) -, (VII) or an imide ring -C (O) -NR ⁴ -C (O) - (VIII) in which R ⁴ corresponds to a C _1-30 hydrocarbon radical or hydrogen atom,
with the proviso that at least 5 mol% of the radicals R ^{2 represent} carboxyl groups or salts thereof and at least 0.1 mol% of the radicals R ^{2 represent} a hydrocarbon radical having more than 8 carbon atoms or a radical of the formulas (IV), (V) or (VI) wherein R ^{4 is} a hydrocarbon radical having more than 8 carbon atoms
and or
a branched vinyl polymer whose linear chains correspond to the general formula (III) and where these chains are linked via the incorporation of vinyl monomers with at least 2 radically polymerizable unsaturated groups.

If in the method according to the invention component (d) is used, it is preferably amounts of 0.05 to 5 parts by weight, per 100 parts by weight of component (a).

Prefers the components (a), (b), (c) and optionally (d) according to step 1 of the method according to the invention presented by these are metered into the mixing vessel, wherein but not complete Mixing of the polyorganosiloxanes with the other components done should. Preferably, during the dosage of components (a), (b), (c) and optionally (d) the stirrer in the Storage tank, in particular if water phase and oil phase are present next to each other, not in use.

components (b), (c) and optionally (d), on the other hand, can be mixed beforehand and as a homogeneous solution be dosed.

First when components (a), (b), (c) and optionally (d) are practical completely present in the mixer, takes place in process step 1 the full Mixing by simple stirring. As agitators All the stirrers used in the prior art come in Question, in particular propeller stirrer, planetary, and anchor stirrer. Preferably planetary or anchor agitators, in particular those, the one walkable Scraper system have used. The stirrer used has a Peripheral speed less than 5 m / s, preferably less than 2 m / s.

If the components (a), (b), (c) and optionally (d) are mixed uniformly are in step 2, the homogenization of the mixture, wherein at least as much mixing energy is used as necessary is about to complete a conversion in an oil-in-water emulsion to reach. The maximum mixing energy depends mainly on the viscosity the polysiloxanes used and the desired particle size. Preferably is the energy input is less than 20 kJ / kg.

For homogenization according to step 2 of the process according to the invention, the mixture can be passed through a rotor-stator homogenizer. The energy input depends, for example, on the gap width and the peripheral speed. The coordination of gap width and peripheral speed with respect to the desired energy input depend on the number of passes through the homogenizer (eg, the degree of backmixing in batch processes in which is homogenized in the circuit) and the geometry of the homogenizer (eg type and arrangement of the teeth the rotor-stator elements) or from the direction of rotation of the homogenizer (eg in homogenizers ent speaking EP-A 290033). Preferably, the peripheral speed of the homogenizer is less than 30 m / s, in particular less than 20 m / s, and the gap width is, for example, 0.3 to 3 mm.

Instead of of rotor-stator homogenizers can in the 2nd step of the process according to the invention also high-pressure homogenizers can be used, as for example in "Schultz, S. et al. Chemie Ingenieur Technik, 74 (7), 901-909, 2002 ". Particularly preferred are high-pressure homogenizers with radial diffusers e.g. of the Gaulin type or alternatively the so-called Microfluidizer in the latter, the use of chambers with chamber sizes greater than 100 μm preferred is. The pressure is preferably less than 500 bar, in particular less than 200 bar.

The inventive method can be carried out batchwise, semicontinuously or continuously; e.g. Step 1 can be achieved by metering the components (a), (b), (c) and optionally (d) take place in a static mixer, as step 2 an inline homogenizer, optionally further dosing and a storage tank for followed by the optional but preferred condensation reaction.

The inventive method is at temperatures of preferably 10 to 50 ° C and a pressure of the surrounding The atmosphere, ie between 900 and 1100 hPa.

The possibly carried out Condensation reaction preferably takes place at temperatures 40 ° C, especially preferably 5 to 40 ° C, especially at temperatures of 15-25 ° C instead. The necessary reaction time until reaching the desired viscosity is easy to identify by experiment in which samples are taken at regular intervals and after breaking the emulsion, the oil viscosity in these samples by conventional methods, e.g. according to DIN 53018.

If the desired viscosity is reached, the pH is preferably in a range of 4-10 in particular set to a range of 6-8. As a neutralizing agent, can e.g. when using acidic emulsifiers such as alkylbenzenesulfonic acids are alkali metal hydroxides such as 10% sodium hydroxide or amines such as monoethanolamine or triethenolamine.

Of the Solids content of the aqueous prepared according to the invention Emulsions can vary within a wide range, with solids contents of 20-70 wt .-% are preferred.

The produced according to the invention Emulsions are varied can be used as release agents, lubricants, water repellents, for Textile impregnation. Preferably are prepared by the process according to the invention Emulsions in care products, especially in hair care products used.

The inventive method has the advantage of providing stable, stable silicone emulsions can be produced.

Surprisingly succeeds with the method according to the invention easy and inexpensive from commercial Fabrics produce stable emulsions, which are excellent Balance of performance properties, e.g. one clearly improved availability of the silicone drug.

In The following examples are all parts information and percentages, Unless otherwise stated, by weight. Unless otherwise The following examples are given at a pressure of the surrounding The atmosphere, So at about 1000 hPa, and at room temperature, ie about 25 ° C or one Temperature, which occurs when combining the reactants at room temperature without additional Heating or cooling, carried out. All listed in the examples viscosity data refer to a temperature of 25 ° C.

example 1

600 g of an α, ω-hydroxy terminated Polydimethylsiloxane with a viscosity of 2090 mPas are in one Laboratory mixer with anchor stirrer and rotor-stator homogenizer, submitted. This is a mixture from 320 g of deionized water and 30 g of dodecylbenzenesulfonic acid (available under the name Marlonic acid AS 3 at Brenntag Eurochem GmbH DE Mühlheim / Ruhr), 1.2 g of an anionic Acrylate thickener (available under the name Pemulen TR2 at Noveon, Inc./9911 Brecksville Road, Cleve land, Ohio, USA). This mixture had a viscosity of 5.6 mPas.

First after all was submitted, the stirrer was switched on and the Mixture stirred for 30 minutes at 50 revolutions per minute. Subsequently was Mix for 5 minutes with a rotor-stator homogenizer 8000 revolutions per minute (corresponds to a diameter of the rotor of 13 mm of a peripheral speed of about 18 m / s) homogenized. The observed temperature rise was less than 2 K. The Entry at mixing energy was thus less than 10 kJ / kg.

After reaching an oil viscosity greater 500,000 mPas of the approach was neutralized with 84 kg of NaOH. The measured by a Malvern Matsersizer volume average particle size was 13.8 microns, the viscosity of the separated oil from the emulsion was 573000 mPas. The emulsion showed no coalescence or oil separation for more than 6 months and was easily processed further.

Example 2

example 1 is repeated with the amendment, that the mixture instead of the rotor-stator homogenizer with a high-pressure homogenizer type APV 2000 (APV Germany GmbH. D-Unna) at one Pressure of 50 bar is homogenized. The emulsion warmed by 2K, the entry of mixing energy was thus less than 10 kJ / kg.

The measured by a Malvern Mastersizer volume average particle size of the resulting emulsion was 11.2 μm. After reaching an oil viscosity of 800,000 mPas, the emulsion was neutralized with triethanolamine. The emulsion showed longer No coalescence or oil separation than 6 months and was trouble-free further processable.

Example 3

example 1 is repeated with the amendment, that as α, ω-hydroxy terminated Polydimethylsiloxane used with a viscosity of 6000 mPas has been.

The measured by a Malvern Mastersizer volume average particle size of the resulting emulsion was 19.4μm. The emulsion showed longer than 6 months no coalescence or oil separation and was easy to process further.

Example 4

1200 kg of a mixture of equal parts of an α, ω-hydroxy-terminated polydimethylsiloxane with a viscosity of 6000 mPas and one with α, ω-hydroxy terminated Polydimethylsiloxane with a viscosity of 60 mPas are in one Mixer with anchor stirrer and rotor-stator homogenizer, which also operated via a bypass can be submitted. The viscosity of this mixture was 1170 mPas.

Of the stirrer was switched on (peripheral speed maximum 1.0 m / s) and a mixture of 640 kg of purified water Pharm. Eur. and 60 kg dodecylbenzenesulfonic acid (available under the name of marlonic acid AS 3 at Brenntag Eurochem GmbH DE Mühlheim / Ruhr was added. These Mixture had a viscosity of 2.3 mPas.

First After everything was submitted, the stirrer speed was increased 2 m / s increased and 5 minutes over the bypass, wherein the direction of rotation of the homogenizer according to EP-A 290033 for optimal pumping operation selected was homogenized at a peripheral speed of 15 m / s. The level of mixing energy was less than 20 kJ / kg.

To Achieving an oil viscosity greater than 1,000,000 mPas, the batch was neutralized with 84 kg of NaOH. The one with one Malvern Mastersizer measured volume average particle size was 6.6 μm, the viscosity of the oil separated from the emulsion was 1.25 million mPas and a content of low molecular weight cyclic siloxanes of less than 1.5%. The emulsion showed longer No coalescence or oil separation than 6 months and was trouble-free further processable.

Example 5

The according to example 1 prepared emulsion was incorporated into a shampoo formulation, as that it contained 1% by weight of polydimethylsiloxane. This shampoo showed excellent storage stability and excellent Conditioned effect.

Claims (3)

A process for the preparation of aqueous silicone emulsions having a volume-average particle size of 1-100μm, characterized in that in a 1st step (a) 100 parts by weight of polyorganosiloxanes containing units of the general formula R _a (R ¹ O) _b SiO _{(4-ab) / 2} (I) wherein R may be the same or different and is a monovalent, optionally substituted hydrocarbon radical having 1 to 30 carbon atoms or hydrogen atom, wherein to a silicon atom at most 1 hydrogen atom is directly bonded, R ^{1 may be the} same or different and is hydrogen atom or a monovalent, optionally substituted hydrocarbon radical a is 0, 1, 2 or 3 and b is 0, 1, 2 or 3, with the proviso that the sum a + b is less than or equal to 3, (b) 1 to 30 parts by weight of an emulsifier, (c ) at least 25 parts by weight of water and (d) optionally further additives such as additional emulsifiers, wetting agents, preservatives, thickeners, dyes or fragrances, are mixed by stirring, wherein the peripheral speed of the stirrer is less than 5 m / s and in a 2. Step the mixture obtained in the first step is homogenized with a homogenizer, the mixture average ma 2 times through the homogenizer is performed and the total energy input during homogenization is a maximum of 200 kJ / kg. Method according to claim 1, characterized in that the viscosity of the polyorganosiloxane (a) at least 10 times that size like the viscosity the mixture of emulsifier (b) and water (c). Method according to claim 1 or 2, characterized in that as emulsifier (b) surface-active Compounds that are simultaneously acidic or basic Catalysts are.