DE19620405B4 - Process for the preparation of aqueous silicone emulsions - Google Patents

Abstract

Process for the preparation of aqueous silicone emulsions, characterized in that
(1) 1 to 40 parts by weight of a homogeneous mixture of
(1a) 0.1 to 5 parts by weight of a first nonionic emulsifier having an HLB value less than 13,
(1b) 0.1 to 5 parts by weight of a second nonionic and / or ionic emulsifier having an HLB value greater than 17,
(1c) 0.1 to 5 parts by weight of a third nonionic emulsifier whose HLB value is between that of the first and the second emulsifier, as well as
(1d) 1 to 5 parts by weight of water per part of emulsifier,
and
(2) 10 to 70 parts by weight of at least one organosilicon compound of the general formula R _a (R ¹ O) _b SiO _{(4-ab) / 2} (I) wherein R is the same and / or different, saturated and / or unsaturated, substituted and / or unsubstituted monovalent hydrocarbon radicals having 1 to 30 carbon atoms and R ^{1 is} hydrogen and / or C ₁ to C ₄ alkyl and a values between 0 and 3 and b Take values between 0 and 4,
homogeneously mixed and
(3) to a total of 100 parts by weight with ...

Description

The The invention relates to a novel process for preparing aqueous silicone emulsions. This may be in solution present and / or mixed with highly dispersed silicic organosilicon Compounds in a homogeneous mixture of three different emulsifiers and water introduced.

silicones are diverse used. To the application and dosage especially viscous Products, it is desirable for many applications that the organosilicon compounds in dilute form. The usage of organic solvents, as benzene or chlorinated hydrocarbons, for this purpose is possible, however from ecological and occupational health point of view. Therefore, the use is done usually in the form of aqueous emulsions or dispersions, usually as oil-in-water emulsions (O / W emulsions) which are dilutable with water. As oil phase are doing the water-immiscible organosilicon compounds understood, possibly solved in organic solvents.

To prepare a finely divided emulsion, the oil phase must be distributed as highly as possible in the water phase. The use of surface-active substances, so-called emulsifiers, is required which reduce the interfacial tension between the oil phase and water and thus facilitate the dispersion. These emulsifiers prevent by steric shielding or electrostatic repulsion that the "oil droplets" meet, unite and grow with it (coalescence). The choice of emulsifiers is thus essential for the fineness of the emulsion as well as for its coalescence stability. Examples of suitable emulsifiers for the preparation of aqueous compositions containing organosilicon compounds include special polyvinyl alcohols ( DE 11 27 078 A ), Polyethers with hydrocarbon groups ( DD 298 651 A5 ), Alkylpolyglycosides ( EP 418 479 A1 ), Polyoxyethylene (16) tridecyl alcohol ( EP 366 133 A2 ) Dodecylsulfonic acid and its salts ( EP 245 658 A2 ) and alkyl phosphates ( DE 27 30 923 A1 ).

In order to obtain stable emulsions, combinations of two liquid emulsifiers are frequently used, such as nonylphenol ethoxylates in combination with anionic surfactants (US Pat. EP 259 734 A2 ), ethoxylated and nonethoxylated sorbitan esters ( US 4,741,861 ), Combinations of polyoxyethylene triglycerides with dioxyethylene-oleyl alcohol ( EP 130 521 A1 ), Mixtures of octylphenol ethoxylates with 3 or 14 ethylene oxide groups ( DE 30 24 870 A1 ) and combinations of an ethoxylated tridecyl alcohol having an HLB value of 11.4 with an ethoxylated triglyceride having an HLB value of 18.1 ( DE 42 23 768 A1 ). The combination of two solid emulsifiers brings, for example, technical advantages in cosmetics ( EP 579 455 A1 ).

Special emulsification processes or combinations of more than two emulsifiers are also possible. For example, it may be advantageous to introduce the emulsifiers one after the other into the mixture and to mix them individually, with water portions also being able to be dosed in between ( EP 463 431 A2 ) EP 200 009 A2 , Also described are specific processes using three specially selected, different emulsifiers, which include polymers ( US 4,788,001 . US 4,803,233 ), which leads to high, not always desirable viscosities.

The aqueous emulsions or dispersions known from the prior art, as oily Phase organosilicon compounds are often not sufficiently stable, too viscous, contain ecologically questionable emulsifiers or the needed Need emulsifiers be incorporated in a complex Dosierregime.

In DE 4332607 A1 For stabilizing silicone-containing wax dispersions, mixtures of several nonionic, cationic or amphoteric emulsifiers are used.

It It was therefore an object of the invention to provide a process for preparing aqueous silicone emulsions which makes it possible to dilute in any proportion with water, stable emulsions reliable and to obtain reproducible.

• (1) 1 bis 40 Gew.-Teile einer homogenen Mischung aus (1a) 0,1 bis 5 Gew.-Teilen eines ersten nichtionogenen Emulgators mit einem HLB-Wert kleiner 13, (1b) 0,1 bis 5 Gew.-Teilen eines zweiten nichtionogenen und/oder ionischen Emulgators mit einem HLB-Wert größer 17, (1c) 0,1 bis 5 Gew.-Teilen eines dritten nichtionogenen Emulgators, dessen HLB-Wert zwischen dem des ersten und dem des zweiten Emulgators liegt, sowie (1d) 1 bis 5 Gew.-Teilen Wasser je Teil Emulgator, und
• (2) 10 bis 70 Gew.-Teile mindestens einer siliciumorganischen Verbindung der allgemeinen Formel R_a(R¹O)_bSiO_(4-a-b)/2 (I),worin R gleiche und/oder verschiedene, gesättigte und/oder ungesättigte, substituierte und/oder unsubstituierte einwertige Kohlenwasserstoffreste mit 1 bis 30 Kohlenstoffatomen sowie R¹ Wasserstoff und/oder C₁ bis C₄-Alkyl bedeuten und a Werte zwischen 0 und 3 sowie b Werte zwischen 0 und 4 annehmen, homogen vermischt und
• (3) auf insgesamt 100 Gew.-Teile mit Wasser verdünnt.

According to the invention

• (1) 1 to 40 parts by weight of a homogeneous mixture of (1a) 0.1 to 5 parts by weight of a first nonionic emulsifier having an HLB value less than 13, (1b) 0.1 to 5 parts by weight of a second nonionic and / or ionic emulsifier having an HLB value greater 17, (1c) 0.1 to 5 parts by weight of a third nonionic emulsifier whose HLB value is between that of the first and of the second emulsifier, and (1d) 1 to 5 parts by weight of water per part of emulsifier, and
• (2) 10 to 70 parts by weight of at least one organosilicon compound of the general formula R _a (R ¹ O) _b SiO _{(4-ab) / 2} (I), wherein R is the same and / or different, saturated and / or unsaturated, substituted and / or unsubstituted monovalent hydrocarbon radicals having 1 to 30 carbon atoms and R ^{1 is} hydrogen and / or C ₁ to C ₄ alkyl and a values between 0 and 3 and b Assume values between 0 and 4, homogeneously mixed and
• (3) diluted to a total of 100 parts by weight with water.

Preferably the emulsifier (1a) has an HLB value between 9 and 13 or less 7. It is particularly preferred that the emulsifier (1c) a HLB value between 15 and 16 has. As a second hydrophilic emulsifier (1b) can ionic, preferably anionic, or nonionic emulsifiers be used.

Of the Term HLB value is z. In "Das Atlas HLB system "Atlas Chem. Ind. 1963 and in K. Shinoda "Emulsion, Microemulsion and Solubilization" (J. Wiley and Sons Inc. 1979).

For the process control according to the invention in a first process step, the emulsifiers and water with each other mixed. This can be achieved both by simple stirring and with homogenizers like colloid mills or rotor-stator homogenizers done. Most of it is simple stir perfectly adequate. For some, especially solid or pasty emulsifiers it may be useful, this mixing process by heating, for. B. at 50 to 70 ° C. to support.

The Emulsifier mixture, which also separated from the actual emulsification in a separate container can be prepared and stored contains 50 to 90 wt .-% water, based on the total amount of emulsifier mixture, wherein 55 to 80 % By weight of water are preferred. Both for the sake of simple process management as also for the quality Of the emulsions produced, it is advantageous if the mixtures from the first, second, third emulsifier and water a homogeneous Represent single-phase system, with which then the organosilicon Compound of the general formula (I), if appropriate in solution and / or as a homogeneous mixture with highly dispersed silicic acid, under the action of shear forces first be processed into a stable paste. This is not a special one Temperature regime necessary, z. B. can the viscosity of the organosilicon Compound, for example by dilution with solvent and / or by heating, on the technical conditions (pump capacity, pipe diameter u. Ä.) Are adapted. The incorporation can be done by simple stirring. However, it is also possible and especially for highly viscous products, it is preferred that the mixture under the action of shear forces, z. Through the use of colloid mills and rotor-stator homogenizers, gives a stable paste and homogenized for at least 10 minutes and then with the up to 100 parts by weight required amount of water dilute become.

For the implementation of the inventive method are mixers with kneading units and homogenizers such as colloid mills, rotor-stator homogenizers or fast stirrer particularly suitable.

To diluting can be a final one single or multiple homogenization with a high pressure homogenizer respectively.

The class of nonionic emulsifiers useful in the process of the invention includes a wide variety of compounds. Such compounds include sorbitan esters, ethoxylated sorbitan esters, ethoxylated fatty alcohols, ethoxylated fatty acids, alkyl polyglycosides, ethoxylated synthetic alcohols, especially branched alkyl, ethoxylated alkyl phenols and many other known emulsifiers. For these nonionic emulsifiers, the HLB value within a class of compounds can vary widely by varying the length of the polyoxyethylene chain on the hydrocarbon radical. Such products are known and commercially available. Preference is given to using ethoxylated triglycerides, ethoxylated fatty alcohols, polyoxyethylene esters of fatty acids and / or ethoxylated synthetic alcohols having at least 12 carbon atoms. As emulsifier (1b), ethoxylated triglycerides having an HLB value greater than 18 are preferred.

Examples for commercially known anionic emulsifiers are sulfuric monoesters of fatty alcohols, Paraffin sulfonates, alkyl succinates, salts of long chain carboxylic acids and many other compounds known to those skilled in the art. Especially preferred are alkyl sulfates, alkyl sulfonates and alkylarylsulfonates.

Examples of preferred emulsifiers are: Emulsifier (1a): Polyoxyethylene (6) tridecyl alcohol (HLB = 11.4) Polyoxyethylene (2) tridecyl alcohol (HLB = 6.2) Polyoxyethylene (3) stearate (HLB = 6.4) sorbitan (HLB = 4.7) Emulsifier (1b): Polyoxyethylene (200) triglyceride (HLB = 18.1) Polyoxyethylene stearate (100) (HLB = 18.8) Polyoxyethylene (40) C _16/18 alkyl ether (HLB = 17.4) Polyoxyethylene (80) C _16/18 alkyl ether (HLB = 19.1) Emulsifier (1c): Polyoxyethylene (15) tridecyl alcohol (HLB = 15.5) Polyoxyethylene (10) tridecyl alcohol (HLB = 14.1) Polyoxyethylene (20) stearate (HLB = 15.0) Polyoxyethylene (10) C _16/18 alkyl ethers (HLB = 12.6) Polyoxyethylene (10) C _12/14 alkyl ethers (HLB = 14.2)

Based on the total amount of the aqueous silicone emulsion are in each case 0.1 to 5% by weight, preferably 0.5 to 2% by weight, used per emulsifier (1a), (1b) and (1c).

When organosilicon compounds of the general formula (I) all known commercially available, water-insoluble organosilicon compounds, in particular organosilicon Polymers used. As radicals R in compound (I) are methyl groups prefers. However, R can also be any other known hydrocarbon radical be. That concludes u. a. following radicals: n-alkyl radicals having 2 to 40 carbon atoms, such as Ethyl, hexyl, cyclohexyl; Iso-alkyl radicals with 3 to 20 carbon atoms, such as isopropyl and isoamyl radicals; alkyl with tertiary Carbon atoms, such as tert-butyl and tert-pentyl radicals; aromatic hydrocarbon radicals, such as. B: phenyl, naphthyl, anthryl radicals; Alkylaryl radicals in which the Silicon either to an aromatic carbon, such as. B. at Tolyl radicals, or to an aliphatic carbon, such as. B. when benzyl radicals, is bound; Radicals with olefinic double bonds, such as As vinyl, allyl and Norbornylreste, as well as substituted Hydrocarbon radicals, such as. Trifluoropropyl, cyanoethyl, Aminopropyl, alkoxyaryl, alkoxyalkyl and haloaryl radicals.

Prefers is the use of silicone oils and silicone resins or their solutions as compounds of general formula (I).

Silicone oils are known as organosilicon compounds in which in general Formula (I) a assumes values of 1.8 to 2.2 and b of 0 to 0.01 and the one viscosity from 10 to 1,000,000 mPas, preferably from 200 to 60,000 mPas, exhibit. Furthermore you can Mixtures of high-viscosity silicone oils with low-viscosity silicone oils or cyclic oligomeric diorganosiloxanes can be used. Especially preferred are polydimethylsiloxanes with hydroxy, trimethylsiloxy and / or Dimethylpolysiloxane. The emulsions prepared according to the invention can also mixtures of silicone oils with fillers, such as As silica, are added. The silicone oils usually become obtained by polymerization and / or polycondensation of the hydrolysis products of dimethyldichlorosilane.

Silicone resins are compounds consisting predominantly of units of the formula RSiO _3/2 . In formula (I), this corresponds to compounds with values of a from 1 to 1.5 and b from 0 to 0.5. The production of these products is also known. They arise z. As in the hydrolysis of trichloro- or trialkoxyorganosilanes, optionally in admixture with other organochlorine or organoalkoxysilanes. Most of this reaction is carried out in several stages in the presence of an organic solvent. Suitable solvents are, for. As aromatics such as toluene, but also aromatic-free white spirits. The solvent can be distilled off during the emulsification process. The radical R in the silicone resins is preferably methyl, phenyl or octyl.

When other ingredients can the inventively prepared aqueous silicone emulsions Thickener, such. B. bentones, polyacrylates, polyvinyl alcohols, cellulose ethers and polyurethanes and biocides, dyes, corrosion inhibitors, Buffers and other known additives contain.

The inventive method allows stable and finely divided emulsions based on silicones very effective and technologically simple to produce.

ever according to the type of silicone contained, the inventively produced Emulsions, for example, as a release agent, as a hydrophobing agent, as a fabric softener, as a defoamer and as an additive to paints and polishes or in other known formulations become.

embodiments

example 1

A solution from 90 wt .-% silicone resin in aromatic-free white spirit with a viscosity from 20 pas at 25 ° C was at 60 ° C heated. At this temperature, the silicone resin solution was well pumpable through tubing. 400 kg of this silicone resin solution were metered into a mixer equipped with an anchor stirrer and a rotor-stator homogenizer was provided. To this solution a homogeneous mixture was added by mixing 6 kg of an ethoxylated tridecyl alcohol having an HLB value of 11.6, 6 kg of an ethoxylated tridecyl alcohol with an HLB value of 14.1, 6 kg of an ethoxylated triglyceride having an HLB value of 18.1 and 33 kg of water had been prepared. Already at stir in in the silicone resin solution a homogeneous white was created until clear solid paste. This was homogenized and gradual diluted with water to 60 wt .-% silicone resin content. The production time was 1.5 h.

Example 2

example 1 was repeated in a 4 liter laboratory mixer. Again it was born from the beginning a homogeneous mixture.

Example 3

Implementation analog Example 2, but instead of the ethoxylated tridecyl alcohol with an HLB value of 14.1 an ethoxylated tridecyl alcohol with used an HLB value of 15.1.

Example 4

Implementation analog Example 2, but instead of the silicone resin solution (60 wt .-%, based on the Total formulation) a polydimethylsiloxane (35 wt .-%, based on the total formulation) of a viscosity of 12500 mPas.

Comparative Example V5

Implementation analog Example 1, except that a mixture of 9 kg of an emulsifier ethoxylated tridecyl alcohol with an HLB value of 11.6 and 30 kg of a 30% solution of an ethoxylated triglyceride having an HLB value of 18.1. The result was an inhomogeneous mixture. After portioned slower Addition of water was homogenized with simultaneous intensive cooling. After 4 hours, 600 kg of a white water dilutable Emulsion received.

Comparative Example V6

Analogous Example 2, except that 120 g of an ethoxylated tridecyl alcohol were used as emulsifier used with an HLB value of 16.3.

Comparative Example V7

Analogous Example 2, only the emulsifiers were successively in the Silicone resin solution mixed.

All the emulsions obtained were centrifuged for 1 h at 4000 min ^-1 to check the emulsion stability and then the clear serum was assessed (centrifuge test) and the volume-average particle size was measured with a laser granulometer.

The Results are summarized in Table 1.

Table 1

It is evident that through the application of the method according to the invention the emulsion quality essential was improved. The according to the examples 1 to 4 produced emulsions have particle sizes of approx. 0.5 μm on. These small particle sizes effect a high stability (see centrifuge test) of the emulsion.

Examples 8 to 13

Implementation analog Example 4, only different emulsifiers were tested. The used emulsifiers are listed in Table 2.

Table 2

In all cases For example, stable emulsions with volume average particle sizes have become essential less than 1 micron.

Example 14

600 kg of a hydroxy-terminated polydimethylsiloxane having a viscosity of 80 mPas and 100 kg of a mixture of ethoxylated tridecyl alcohol with an HLB value of 11.6, ethoxylated tridecyl alcohol with a HLB value of 14.1, ethoxylated triglyceride with an HLB value of 18.1 and water in the ratio 1: 1: 1: 7 were in a stirred tank stirred. 300 kg of water were slowly stirred into the mixture. It there was a white one homogeneous emulsion by homogenizing three times with a High-pressure homogenizer at 25 MPa is completed. The emulsion had excellent stability.

Claims (11)

Process for preparing aqueous silicone emulsions, characterized in that (1) 1 to 40 parts by weight of a homogeneous mixture of (1a) 0.1 to 5 parts by weight of a first nonionic emulsifier having an HLB value less than 13, (1b ) 0.1 to 5 parts by weight of a second nonionic and / or ionic emulsifier having an HLB value greater than 17, (1c) 0.1 to 5 parts by weight of a third nonionic emulsifier whose HLB value between the des and (1d) 1 to 5 parts by weight of water per part of emulsifier, and (2) 10 to 70 parts by weight of at least one organosilicon compound of the general formula R _a (R ¹ O) _b SiO _{(4-ab) / 2} (I) wherein R is the same and / or different, saturated and / or unsaturated, substituted and / or unsubstituted monovalent hydrocarbon radicals having 1 to 30 carbon atoms and R ^{1 is} hydrogen and / or C ₁ to C ₄ alkyl and a values between 0 and 3 and b Take values between 0 and 4, mix homogeneously and (3) dilute to a total of 100 parts by weight with water. Method according to claim 1, characterized in that that the Emulsifier (1a) has an HLB value between 9 and 13 or less than 7. Method according to claim 1, characterized in that that the Emulsifier (1c) has an HLB value between 15 and 16. Method according to claim 1, characterized in that that as nonionic emulsifiers ethoxylated triglycerides, ethoxylated fatty alcohols and / or polyoxyethylene esters of fatty acids and / or ethoxylated synthetic Alcohols having at least 12 carbon atoms can be used. Method according to claim 1, characterized in that that as ionic emulsifiers (1b) alkyl sulfates, alkyl sulfonates or alkylarylsulfonates be used. Method according to claim 1, characterized in that that pro Emulsifier (1a), (1b) and (1c) each 0.5 to 2 parts by weight, based to 100 parts by weight of total preparation. Method according to claim 1, characterized in that that as organosilicon compounds of the general formula (I) such be used in which a values between 1.8 and 2.2 as well b assume values between 0 and 0.01. Method according to claim 1, characterized in that that as organosilicon compounds of the general formula (I) such where a values between 1 and 1.5 and b Assume values between 0 and 0.5. Method according to claim 1, characterized in that that as organosilicon compounds of the general formula (I) such be used, which has a viscosity between 10 and 1 000 000 mPas have. Method according to claim 1, characterized in that that the organosilicon compound of general formula (I) dissolved in one organic solvents is used. Method according to claim 1, characterized in that that the organosilicon compound of general formula (I) as a mixture with highly dispersed silicic acid is used.