DE1955556C3 - Liquid dispersion medium - Google Patents

Description

The invention relates to liquid aqueous dispersion media and their use for the production of dispersions with a stable disperse phase of finely divided solid material, from droplets of spherical material, e.g. B. with water immiscible liquids, and from gas bubbles, such dispersions in temperature ranges from -5 to 30 ⁰ C are stable.

It is known that the suspension capacity of aqueous solutions of a nonionic surface-active agent is dependent on micellar effects. At low concentrations of nonionic surface-active agendas, a simple micella shape prevails, consisting of spherical aggregates of molecules of the surface-active agent with the water-soluble head groups on the surface and the hydrocarbon chains forming a liquid core. At higher concentrations, the spherical shape is replaced by more elongated micella shapes, e.g. by cylindrical types (Francois υ, a, J. Colloid Int Sei, 21, p. 293 [1966]). Simple watery

ίο Solutions of a nonionic surface active

Agents do not have the ability to suspend because of the Degree of action between the non-ionic Micelles is insufficient The invention relates to that in the claims

marked items.

Compared to the previously known liquid dispersion media, the inventive show the advantage that dispersions can be obtained with them which are stable for significantly longer; are also the dispersion

media can be used more universally.

Presumably, the nonionic surfactant and the soap form mixed mixtures which unusually active surfaces due to the small size of the water-soluble group of the nonionic surface-active agent and therefore have a low degree of hydration on the micella surface. In in practice, the small size of this water-soluble group makes it nonionic surface-active Agent too insoluble to form micelles on its own, and the surprisingly small amount of soap acts as a a mixed micelle-forming agent to form a micellar solution of the nonionic surfactant in to generate the water.

The additive is said to be on the micellar surface

adsorb to an increase in the micellar interaction within this mixed micellar To cause a solution which gives suspending power to the dispersion medium

The relevant nonionic surfactants

Agents are on the verge of micelle formation in water. The HLB value is the hydrophilic / hypophilic balance (W. C Griffin, J. Soc. Cosmetic Chemists, /, [1949J P. 311). The HLB value calculated for a surfactant is not accurate. In practice you can nonionic surfactants, that are

Alkylene oxide condensates, which are complex mixtures

are controlled to determine whether they have an appropriate HLB value.

The determination is carried out by testing their solubility

ability in 5 weight percent concentration in distilled Water at the required temperature from a number of condensates of alkylene oxide with the reagent which forms the hydrophobic group. This series is increasing using Quantities of alkylene oxide formed. The first non-ionic surface-active agent, which is a sharp Decrease in turbidity relative to the previous condensate of lower alkylene oxide content shows, indicates the critical point in the series at which micellar formation begins. A condensate, whose HLB value is calculated or determined to be half a unit below that which one shows sharp decrease in opacity, is at the limit of the formation of micelles and is to

Use suitable.

The HLB value of an ethylene oxide condensate is approximately equal to one fifth percent by weight of that at Ethylene oxide used for condensation. That the

condensate showing a sharp decrease in turbidity contains more than one additional ethylene oxide unit the usable condensate, and an ethyylene oxide unit corresponds to about half an HLB unit

Cooling or heating of the dispersion medium below or above that used in the test Temperature can result in a decrease or loss of suspending ability.

Suitable nonionic surface-active agents can be found among fatty acid alkylolamides and alkylene oxide condensates of aliphatic alcohols, alkylphenols, alkylamines, fatty acid alkylolamides and alkyl mercaptans. The ethylene oxide condensates are preferred.Suitable nonionic surface-active agents for liquid media, usable for the preparation of dispersions for storage and use at up to 30 ° C (their calculated HLB values are given in brackets) are: Condensates of nonylphenol with 7 molar equivalents of ethylene oxide (11 , 6), pentadecanol with 6 molar equivalents of ethylene oxide (11.5), CirCM-alkylamine with 3 molar equivalents of ethylene oxide (11.5), octylphenol with 6 molar equivalents of ethylene oxide (11.6), coconut monoethanolamide with 2 molar equivalents of (10), CirC _M -alkanol with 6 molar equivalents of ethylene oxide (11.4), and in particular lauric diethanolamide (10.0). The HLB values of the condensates mentioned are those of the pure condensates, free of impurities that may be present in commercial products.

The concentration of the nonionic surfactant is preferably from 5 to 15 percent by weight of the dispersion medium, and is the most effective Concentration will be within these limits for various non-ionic surface-active agents fluctuate, because the micella shape is synonymous with the Concentration varies as with the chemical type of the nonionic surface active agent the optimal concentration for one agent may be 6%, but for another 6% may not be enough, but with him 10% are required.

The soap can be an alkali metal soap, e.g. the sodium and potassium salt or an ammonium or organic ammonium salt, e.g. a diethanolamine salt a fatty acid with 12 to 19 carbon atoms. Natural fatty acid mixtures, for example the Fatty acids from peanut oil and coconut oil can be used as acid components in soap. Suitable Soaps are sodium runate, sodium stearate, diethanolamine oleate and the potassium soap of peanut oil fatty acids. Diethanolamine laurate is preferably used The preferred concentration of soap is from 0.02 to 0.08 percent by weight of the dispersion medium.

Particularly suitable additives which have the required solubility in dodecane and in water up to are soluble to the extent indicated in brackets are: n ^ hexane (0.015), n-heptane (0.01), cyclohexene (0.02), dipentene (0.04), terpinolene (0.04), benzene (0.18), Toluene (0.06), xylene (0.02), nitrobenzene (0.25), chlorobenzene (0.03), 34 * dimethoxy-4-chlorobenzene (0.02), Safro! (0.02), dibutyl phthalate (0.01), n-octyl alcohol (0.06), 2-ethylhexanol (0.02), Laüfylalköhöl (0.01) and decylamine (0.04). Preferably from 0.5 to 1% of the additive is present by weight of the dispersing medium.

Organic bases containing fewer than 8 carbon atoms are unsuitable, for example n-hexylamine, aniline and cyclohexylamine. Synthetic anionic detergents must be removed from the dispersion medium be excluded.

Some commercial grades of usable non-chemical surface-active agents may contain one or the other essential component, ζ, B, soap, or the additive can also be present be. Many commercial grades of lauric diethanolamide contain dietbanol amulaurate, which is a soap if the nonionic surfactant is a Commercial ethylene oxide condensate of an alcohol

to is, it may very well be some unreacted alcohol lock in. When this alcohol meets the definition of the additive and in prescribed amounts is present, the dispersion medium can be made nonionic by simply mixing this commercially available one surfactant and a soap in

Water build up. If the alcohol is such

is a defined additive, then it must be removed, before the dispersion medium is made.

The solid, fine-particle material in the dispersions,

which are produced using the dispersion medium can be, for example: particles made of silica, quartz. Feldspar, kaolin, carborundum, encapsulated material, insoluble active detergent material, solid germicide and solid soil redeposition additive.

The solid particles can range in particle size, for example from 1 to 5000 microns in diameter. The upper? Size limit depends on the density of the particles to the extent that the closer the particles are to the particle size required for a stable suspension so smaller particles of a size of 100 micron diameter and a density of 2J5 g / cc, z. B. powdered silica can be suspended in a stable manner. To determine whether a given particulate material can be consistently suspended the following equation can be used. This equation relates to the ratio of densities to maximum particle size for the suspension. If d, is the density in g / cc of the particles to be suspended and d _o c? 'E density of the dispersion medium, then the diameter D in microns of the largest particles to be suspended can be derived from the equation D (d, -d _o ) = \ 5Q to be calculated. Particles larger in diameter than the size calculated from the above equation can only be suspended for shorter times.

If pourable suspensions are required, at least 30% of the dispersion medium should be used in terms of weight of the entire compilation

so be present. The dispersion preferably contains from 5 to 55 percent by weight of solid, finely divided material from the dispersion. However, if desired, the dispersion may contain less than 5%, for example 0.1 to 5%. A dispersion medium useful for pourable dispersions has a viscosity of 0.2 to 3 poises as measured at a shear ratio within the range of 5 to 1000 seconds. ^1st

If the dispersion contains drops of an immiscible liquid, their size can be selected,

eo to give a visible effect. The droplet size can be between 1 and 2000 microns, preferably from 50 to 2000 microns, in diameter, and the The concentration of the droplets is preferably from 0.1 to 20 percent by weight of the dispersion. Higher Concentrations of droplets can affect the distribution of the nonionic surfactant, soap and Additive to the detriment of the suspension capacity. The migration of the soap to intermediate

area is probably responsible for this effect. The size of the existing droplets hingt upon the relative viscosities of the droplets and aer Dispersionsmediumsund from the expended in preparing the dispersion energy.

The aqueous dispersions can also contain dispersed gas phases. Suitable dimensions for such Bubbles are under 150 microns in diameter, and their concentration can range from 0.002 to 0.1 percent by weight of the dispersion.

To produce the dispersion medium according to the invention, the nonionic surface-active Agent dissolved in water along with the soap as the mixed micellarizing agent; the additive will

then added to form the dispersion medium, wherein the solid, liquid or gaseous material is then dispersed.

The invention is illustrated by the following examples. An abbreviation such as e.g., Nonylphenol. 7 ÄO means the condensation product of nonylphenol and 7 molar equivalents of ethylene oxide. That used Commercially available lauric diethanolamide contained 3 percent by weight DiethanoIaminJaurat, In Examples I. to 11, the specified amounts are by weight of the dispersion medium; in Examples 12-20 it is by weight based on the total aqueous dispersion and the remainder to 100% is water.

Examples
No. Nonionic surfactant soap Additive 1 10% nonylphenyl-7 AO 0.02% dietbanolamine laurate 0.9% benzene 2 10% PentadecanolHf) ÄO 0.03% diethanolamine laurate 0.5% benzene 3 8% Gi2-14-alkylamine-3 ÄO 0.08% diethanolamine laurate ■ 0.9% benzene 4th 10% octylphenol-6 ÄO 0.03% diethanolamine laurate 0.9% dipentene 5 10% C, 2-M-Alkanol-6 ÄO 0.05% diethanolamine laurate 0.9% nitrobenzene 6th 10% pentadecanoI-6 EO 0.03% diethanolamine laurate 1% lauryl alcohol 7th 10% NonyIphenol-7 ÄO 0.025% sodium stearate 0.5% benzene 8th 10% nonylphenol-7 ÄO 0.06% sodium laurate 0.9% benzene 9 10% nonylphenol-7 ÄO 0.1% potassium peanut oil soap 0.5% benzene (commercially available) 10 8% commercial laurine 0.024% diethanolamine laurate 1% benzene diethanolamide as an impurity Il 8% commercial laurine 0.024% diethanolamine laurate 1% n-hexane diethanolamide as an impurity

In each of the compositions of Examples 1 to 11, the solid, finely divided material is as required dispersed

No. Compositions Particle size of suspen
dated material
in density in g / cc Stability at 25 ° C in microns 2.6 12th 83% nonylphenol-7 EO
0.017% diethanolamine laurate
0.765% benzene
15% kaolin 20-50 2.4 Just a small amount of clearer
Liquid on the surface of the
System after 6 months. That
suspended material was good
distributed in the bulk of the solution 13th 9.0% pentadecanol-6 AO
0.027% diethanolamine laurate
0.45% benzene
10% silica 2%> 100
48%:
50-100
50% <50 2.7 Resistant after 6 months 14th 8% nonylphenyl-7 AO
0.048% sodium laurate
0.72% benzene
20% calcite 50-80 2.4 Resistant after 6 months 15th 5.6% Ci2-H-alkylamine-3 ÄO
0.056% diethanolamine laurate
0.63% benzene
30% silica 2%> 100
48%:
50-100
50% <50 Resistant after 6 months. One
small amount of clear liquid
on the surface
9 months

(Continuation)

Compositions

Particle size of suspended material in density

Stability at 25 ° C

in microns

in g / cc

16 6% nonylphenol-7 ÄO 50-80 2.7 0.06% potassium soap from peanut oil fatty acids

0.3% benzene 40% calcium it

17 4.8% commercial lauric 2%> 100 2.4 ethanolamide, containing 0.14% 48%: Diethanolamine Laurate 50-100

0.6% benzene 50% <50

40% silica

18 7.2% commercial laurindi- 0.1-0.2 2.4 ethanolamide, containing 0.22 "/ ο

Diethanolamine laurate 0.9% n-hexane 10% silica

19 6.4% commercial laurindi- 150-250 3.2 ethanolamide, containing 0.19%

Diethanolamine laurate 0.8% benzene 20% carborundum

20 8% commercial Laurindi- 500! 7

ethanolamide, containing 0.24%
Diethanolamine laurate
0.8% benzene
1.0% silicone oil with a
Viscosity of 10 poises
0.02% more soluble in silicone oil
dye

Resistant after 8 months; no visible sign of deposition

Persistent after 8 months; no sign of deposition

Resistant after 6 months; no sign of deposition

Although the maximum particle size for an optimal suspension with that density is 65 microns. the particles still remained suspended after 3 months in the liquid and only 5% clear liquid had settled on the surface

Resistant after 6 months

Claims (6)

Claims; J, Liquid dispersion medrome, consisting of Water, a nonionic surface-active agent and a soap, characterized in that that the nonionic surfactant has from 12 to 16 carbon atoms in the hydrophobic part of its molecule, has an HLB value of 10 to 12 and is close to formation of micelles at the temperature at which dispersibility is required is from 0.01 to 0.2% of the weight of the liquid medium soap is present, and that in addition 0.5 to 2% by weight of the liquid medium is present on an additive, which is an organic compound is that in dodecane in an amount of at least 10 percent by weight at 25 ° C and in distilled Water in an amount of 0.01 to 2 percent by weight at 25 "C is soluble and from the group Consists of benzene, substituted benzenes, naphthalene, alcohols with 8 to! 4 carbon atoms, paraffinic hydrocarbons with 6 to 8 Carbon atoms, unsaturated hydrocarbons with S to 14 carbon atoms, in particular Terpenes, dibutyl phthalate and aliphatic amines with at least 8 carbon atoms is selected. 2. Liquid dispersion medium according to claim 1, characterized in that from 5 to 15% of the nonionic surfactant present by the weight of the liquid dispersion medium are. 3. Liquid medium according to claim 1 or 2, characterized in that the nonionic surfactant is a fatty acid alkylolamide or an alkylene oxide condensate of an aliphatic alcohol, an alkylphenol, an alkyiamine, a fatty acid alkylolamine or an alkyl mercaptan is. 4. Liquid medium according to claim 1 or 2, characterized in that the nonionic surface-active agent is lauric diethanolamide 5. Liquid medium according to one of the preceding claims, characterized in that the Soap is diethanolamine laurate 6. Use of the liquid medium according to one of the preceding claims for the production of dispersions with a constant disperse phase from finely divided solid material, from droplets a liquid immiscible with water or from gas bubbles.