EP0725805A1

EP0725805A1 - Process for producing wax dispersions

Info

Publication number: EP0725805A1
Application number: EP94931535A
Authority: EP
Inventors: Bernd Wahle; Peter Waltenberger; Claudia Klink; Thomas Förster; Thomas Engels
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1993-10-29
Filing date: 1994-10-20
Publication date: 1996-08-14
Also published as: JPH09504315A; US5723137A; WO1995011936A2; WO1995011936A3; DE4337030A1

Abstract

Finely dispersed wax dispersions with a long shelf life can be obtained by heating: (A) 10 to 80 wt. % of wax with, (B) 0.5 to 30 wt. % of a hydrophilic non-ionic dispersant with an HLB value of 8 to 18 and, (C) 1 to 30 wt. % of a hydrophobic Co dispersant from the group of fatty alcohols with 12 to 22 C atoms or the partial esters of polyols with 3 to 6 C atoms with fatty acids with 12 to 22 C atoms, provided that the ratio of components (B) and (C) is in the range from 0.5:1 to 20:1, in the presence of 15 to 85 wt. % of water to a temperature above the melting point of the mixture of components (A) to (C) and then heating the dispersion obtained to a temperature within or above the phase inversion point, or producing the dispersion directly at this temperature, and subsequently cooling the dispersion to a temperature below the phase inversion range and possibly further diluting it with water.

Description

"Process for the Production of Wax Dispersions"

Field of the Invention

The invention relates to a process for the preparation of wax dispersions under conditions which lead to finely dispersed and long-term stable dispersions.

State of the art

It is known that oil-in-water emulsions, henceforth called O / W emulsions, which are produced and stabilized with nonionic emulsifiers, undergo phase inversion when heated. This process of phase inversion means that the outer, aqueous phase becomes the inner phase at higher temperatures. This process is generally reversible, which means that the original emulsion type re-forms when it cools down. It is also known that the position of the phase inversion temperature depends on many factors, for example the type and phase volume of the oil component, the hydrophilicity and the structure of the emulsifier or the composition of the emulsifier system, compare, for example, K. Shinoda and H. Kunieda in Encyclopedia of Emulsion Technology, Volume I, P. Becher (ed.), Marcel Decker, New York 1983, pp. 337 ff.

DE-A-38 19 193 discloses a process for producing low-viscosity O / W emulsions using phase inversion technology. This technique is applied to mixtures containing an oil component, a nonionic emulsifier and a coemulsifier in an aqueous medium. The oil component should consist of 50-100% special mono- or diesters, 0-50% Cg-C22-F ^et ' ^ts acid triglycerides and optionally 0-25% of a hydrocarbon oil.

DE-A-41 40 562 discloses a process for producing O / W emulsions with particularly polar oil bodies by means of phase inversion technology. Particularly polar oil bodies are understood to mean oils with a dipole moment above 1.95 D. The technique of phase inversion is applied to mixtures which contain the above-mentioned particularly polar oils, a nonionic emulsifier, possibly a coemulsifier, and an interface moderator, which is from the group of tocopherols, Guerbet alcohols with 16 to 20 carbon atoms or a steroid with 1 to 3 OH groups is selected.

DE-A-38 19 193 and DE-A-4140 562 do not disclose any further components beyond the components mentioned. In particular, these publications do not contain any indication as to whether and by what measures it is possible to produce finely dispersed and long-term stable wax dispersions.

Description of the invention

The object of the present invention was to develop a method for producing finely dispersed and long-term stable wax dispersions.

This object was achieved in that

(A) 10 to 80 wt .-% of a wax with

(B) 0.5 to 30% by weight of a hydrophilic nonionic dispersant with an HLB value of 8 to 18 and

(C) 1 to 30% by weight of a hydrophobic co-dispersant from the group of fatty alcohols with 12 to 22 C atoms or the partial esters of polyols with 3 to 6 C atoms with fatty acids with 12 to 22 C atoms, with with the proviso that the ratio of components (B) and (C) is in the range from 0.5: 1 to 20: 1, in the presence of 15 to 85% by weight of water to a temperature above the melting point of the mixture of the Components (A) to (C) heated and the dispersion obtained is then heated to a temperature within or above the phase inversion temperature range - or the dispersion is produced directly at this temperature - and then the dispersion is cooled to a temperature below the phase inversion temperature range and optionally further diluted with water.

The invention therefore relates to a process for the preparation of wax dispersions

(A) 10 to 80 wt .-% of a wax with

(C) 1 to 30% by weight of a hydrophobic co-dispersant from the group of fatty alcohols with 12 to 22 C atoms or the partial esters of polyols with 3 to 6 C atoms with fatty acids with 12 to 22 C atoms, with with the proviso that the ratio of components (B) and (C) is in the range from 0.5: 1 to 20: 1, in the presence of 15 to 85% by weight of water to a temperature above the melting point of the mixture of the Components (A) to (C) are heated and the dispersion obtained is then heated to a temperature within or above the phase inversion temperature range - or the dispersion is produced directly at this temperature - and then the dispersion is cooled to a temperature below the phase inversion temperature range and optionally further diluted with water.

The process according to the invention has the advantage that particularly finely divided dispersions are obtained which have excellent storage stability. Compared to the known prior art, e.g. B. DE-OS-38 19 193, the phase inversion temperature is also reduced, which is particularly advantageous in practice because of the energy savings associated therewith.

Under waxes, ie component (A), are - following the usual use in the specialist world (cf., for example, 0.-A. Neumüller, "Römpps-Chemie-Lexikon, 7th edition, Stuttgart 1977, page 3857) - understood natural or artificial substances that are solid and kneadable at 20 ° C, are coarse to fine crystalline and only change to a flowable, lower viscous state above about 40 ° C. without decomposition.

The type and origin of the waxes (A) are not subject to any restrictions in the context of the present invention. The waxes (A) can accordingly be selected from each of the three groups into which the waxes are usually classified. These three groups are

1) Natural waxes, namely: (a) vegetable waxes, which are divided into recent waxes such as candelilla, caranuba, japan, esparto grass, ouricoury wax and fossil waxes such as montan wax, etc .; (b) animal waxes such as bees wax, shellac wax, walrus, lanolin (wool wax), pretzel fat, etc .; (c) mineral waxes (petroleum waxes) such as ceresin, ozokerite (earth wax), petrolatum, paraffin and micro waxes,

2) chemically modified waxes e.g. B. the oxidized products made from raw montan wax,

3) synthetic waxes, also called synthetic waxes, e.g. B. from the paraffins obtained by the Fischer-Tropsch process, which are converted into a series of hard waxes by air oxidation, selective solvent treatment, esterification, saponification, etc. Polyethylene waxes, which are produced partly from high-molecular low-pressure polyethylene by high-pressure polymerization of ethylene and partly by cracking, as well as corresponding oxidized products, belong to the synthetic waxes.

In addition to the waxes (A), if desired, liquid oils and / or liquid hydrocarbons can also be present. The characteristic "liquid" refers to the consistency of the oils or hydrocarbons at 20 ° C.

Particularly suitable oils are mono- and diesters of the general formula (I), (II) and (III)

(I) Rl-COOR ²

(II) R2-00C-R3-C00R ²

(III) R1-C00-R3-00C-R ¹ wherein R ^{1 is} an alkyl group with 8 to 22 C atoms and R ^{2 is} an alkyl group with 3 to 22 C atoms and R3 alkylene groups with 2 to 16 C atoms, with the proviso that the total number of C atoms in the compounds (I) to (III) is at least 11.

Oils of the type of the mono- and diesters of the formulas (I), (II) and (III) are known as cosmetic and pharmaceutical oil components and as lubricants and lubricants. Monoesters (I) suitable as oils are e.g. the isopropyl esters of fatty acids with 12 to 22 carbon atoms, e.g. Isopropyl myristate, isopropyl palmitate, isopropyl stearate, isopropyl oleate. Other suitable monoesters are e.g. n-butyl stearate, n-hexyl laurate, n-decyl oleate, isooctyl stearate, isononyl palmitate, isononyl isononanoate, 2-ethylhexyl palmitate, 2-ethylhexyl laurate, isotridecyl palmitate / stearate, 2-hexyldecyl-octyl-stylate , Oleyl oleate, Oleylerucat, Erucyloleat as well as esters, which are obtainable from technical aliphatic alcohol mixtures and technical aliphatic carboxylic acids, eg Esters from saturated and unsaturated fatty alcohols with 12 to 22 C atoms and saturated and unsaturated fatty acids with 12 to 22 C atoms, as are obtainable from animal and vegetable fats. Naturally occurring monoester or wax ester mixtures, such as those e.g. in jojoba oil or sperm oil, provided that they are liquid at 20 ° C.

Suitable dicarboxylic acid esters (II) are e.g. Di-n-butyl adipate, di-n-butyl sebacate, di- (2-ethylhexyl) adipate, di- (2-hexyldecyl) succinate and di-isotridecyl acelaate. Suitable diol esters (III) are e.g. Ethylene glycol dioleate, ethylene glycol di-isotridecanoate, propylene glycol di- (2-ethylhexanoate), propylene glycol di-isostearate, propylene glycol di-pelargonate, butanediol di-isostearate and neopentyl glycol di-caprylate.

Esters of trihydric and polyhydric alcohols, in particular vegetable triglycerides, e.g. Olive oil, almond oil, peanut oil, sunflower oil or also the esters of pentaerythritol with e.g. Pereganoic acid or oleic acid.

As fatty acid triglycerides, natural, vegetable oils, e.g. B. olive oil, sunflower oil, soybean oil, peanut oil, rapeseed oil, almond oil, palm oil, but also the liquid portions of coconut oil or palm kernel oil as well as mineral oils such as B. claw oil, the liquid portions of beef tallow or synthetic triglycerides, as obtained by esterification of glycerol with fatty acids with 8 - 22 carbon atoms, for. B. triglycerides of caprylic acid-capric acid mixtures, triglycerides from technical oleic acid or from palmitic acid-oleic acid mixtures are used.

Examples of suitable hydrocarbons are paraffin oils and synthetic hydrocarbons, e.g. B. liquid polyolefins or defined hydrocarbons, for. B. alkylcyclohexanes such. B. the 1,3-di-isooctylcyclohexane.

Substances suitable as hydrophilic nonionic dispersants (B) are characterized by a lipophilic, preferably linear alkyl or acyl group and a hydrophilic group formed from low molecular weight glycol, glucose and polyol ethers.

The dispersants (B) are used in the wax dispersions according to the invention in an amount of 0.5 to 30% by weight, preferably 3 to 20% by weight.

Particularly suitable dispersants (B) are ethylene oxide adducts on fatty alcohols with 16 to 22 carbon atoms. Such products are commercially available. The technical products are mixtures of homologous polyglycol ethers of the starting fatty alcohols, the average degree of oxyethylation of which corresponds to the molar amount of ethylene oxide added. Ethylene oxide addition products onto partial esters of a polyol with 3 to 6 C atoms and fatty acids with 14 to 22 C atoms can also be used as dispersants. Such products are produced, for example, by ethoxylation of fatty acid partial glycerides or of mono- and di-fatty acid esters of sorbitan, for example sorbitan monostearate or sorbitan sesquioleate. The dispersants suitable for the process according to the invention should have an HLB value of 8 to 18. The HLB value (hydrophile-lipophile balance) is to be understood as a value that can be calculated according to HLB = 100 - L

where L is the weight fraction of the lipophilic groups, i.e. H. the percentage of fatty alkyl or fatty acyl groups in the ethylene oxide adducts.

Preferred dispersants (B) are fatty alcohol polyglycol ethers (B1) of the general formula (IV)

R4- (0-CH ₂ -CH ₂ ) _n -0H (IV)

in which R 1 is a saturated or unsaturated, straight-chain or branched hydrocarbon radical having 8 to 22 carbon atoms, preferably 12 to 22 carbon atoms and n an integer from 10 to 50, preferably 10 to 30, and addition products from 4 to 20 moles of ethylene oxide to one or more fatty acid partial glycerides (B2).

Fatty acid partial glycerides (B2) of saturated or unsaturated fatty acids with 10 to 20 C atoms are technical mixtures of fatty acid mono-, di- and triglycerides which are esterified by 1 mole of glycerol with 1 to 2 moles of a (Cιo- 2θ) " ^{f: et} ' ^fcs ^ure or by transesterification of 1 mole of a (Cιo_2θ) ~ ^{fatty acid} tr i9Ϊy ^cer ids, for example beef tallow, lard, palm oil, sunflower oil or soybean oil with 0.5 to 2 moles of glycerol Two types of partial glycerides are commercially available: Partial glycerides of type I contain 35 to 60% monoglycerides, 35 to 50% diglycerides and 1 to 20% triglycerides contain 90 to 96% monoglycerides, 1 to 5% diglycerides and less than 1% triglycerides (see also: a) G. Schuster and W. Adams: Zeitschrift für Lebensmitteltechnologie, 1979, volume 30 (6), pp. 256-264 ; b) G. Schuster (ed .) "Food Emulsifiers", Springer-Verlag, 1985). The fatty acid partial glycerides used according to the invention should contain 35 to 96% monoglycerides, 1 to 50% diglycerides and 0.1 to 20% triglycerides. Addition products of 8 to 12 mol ethylene oxide onto saturated fatty alcohols having 16 to 22 carbon atoms are particularly suitable as dispersants. For the inventive alloying of oil components which do not contain non-polar hydrocarbon oils, which therefore consist of 50 to 100% by weight of mono- and diesters of the formulas I, II and III and 0 to 50% by weight of fatty acid triglycerides are particularly suitable as dispersants adducts of 8 to 12 moles of ethylene oxide with a saturated fatty alcohol having 18 to 22 carbon atoms.

In addition to the dispersant (B), the process according to the invention requires the presence of a co-dispersant (C). As co-dispersants according to the invention are those of the type of fatty alcohols with 16 to 22 C atoms, e.g. B. cetyl alcohol, stearyl alcohol, arachidyl alcohol or behenyl alcohol or mixtures of these alcohols, as are obtained in the industrial hydrogenation of vegetable and animal fatty acids with 16 to 22 C-atoms or the corresponding fatty acid methyl ester. Also suitable as co-dispersants are partial esters made of a polyol with 3 to 6 carbon atoms and fatty acids with 14 to 22 carbon atoms. Such partial esters are e.g. B. the monoglycerides of palmitic and / or stearic acid, the sorbitol mono- and / or diesters of myristic acid, pal itic acid, stearic acid or mixtures of these fatty acids, the monoesters of trimethylolpropane, erythritol or pentaerythritol and saturated fatty acids with 14th up to 22 carbon atoms. The technical monoesters which are obtained by esterification of 1 mole of polyol with 1 mole of fatty acid and which are a mixture of monoesters, diesters and unesterified polyol are also understood as monoesters.

Cetyl alcohol, stearyl alcohol or a glycerol, sorbitan or trimethylolpropane monoester of a fatty acid with 14 to 22 carbon atoms or mixtures of these substances are particularly suitable as co-dispersants for the process according to the invention.

The co-dispersants (C) are used in the wax dispersions according to the invention in an amount of 1 to 30% by weight. The range from 2 to 20% by weight is preferred. As already mentioned, the ratio of components (B) and (C) is a critical parameter for the success of the method according to the invention. The ratio of (B) and (C) should be in the range from 0.5: 1 to 20: 1. A range from 1: 1 to 10: 1 is preferred. From a functional point of view, the ratio of components (B) and (C) is set such that the phase inversion temperature of the entire composition is above the melting point of the solid wax (A) and below 100 ° C.

In addition to the components mentioned, other components can also be contained in the wax dispersion. In this context, interface moderators from the group of tocopherols, Guerbet alcohols with 16 to 20 C atoms and steroids with 1 to 3 OH groups may be mentioned in particular.

Tocopherols are natural substances with a vitamin E character which are derived from 2-methyl-2- (4 '.8'.12'-trimethyltridecyl) -chroman-6-ol, the so-called tocol. The identification is made with Greek letters (see "Römpps Chemie-Lexikon", 0.-A.Neumüller (ed.), 7th edition, Stuttgart 1977, p. 3615f). Especially preferred is α-tocopherol, the most common and technically most important tocopherol, which is often referred to as the actual vitamin E. Guerbet alcohols are to be understood as meaning special branched alcohols (cf. eg AJ 0'Lenick Jr., RE Bilbo, Soap Cos. Chem. Spec. 1987 (4) 52). The Guerbet alcohols to be used according to the invention should have 16 to 20 C atoms, such as 2-hexyldecanol or 2-0ctyldodecanol. 2-0ctyldodecanol is particularly suitable. Steroids are to be understood as a group of naturally occurring or synthetically obtained compounds which are based on the framework of the (partially) hydrogenated cyclopenta [a] phenanthrene, cf., for example, OA Neumüller, Römpps Chemie-Lexikon, 7th ed. , Stuttgart 1975, pp. 3336 ff. The steroids should have 1 to 3 OH groups. The sterols in which an OH group is located on the third carbon atom of the steroid structure are particularly suitable. The sterols occur in all animal and plant cells. After their occurrence, they are divided into zoosterols, for example cholesterol, and phytosterols, which are predominantly found in higher plants. A particularly suitable steroid is cholesterol. The process according to the invention can be carried out by first determining the phase inversion temperature by heating a sample of the dispersion prepared in the customary manner using a conductivity meter and determining the temperature at which the conductivity decreases sharply. The decrease in the specific conductivity of the oil-in-water dispersion initially present usually decreases over a temperature range from 5 to 15 ° C. from initially approximately 50 microsiemens per cm to values below 5 microsiemens per cm. The corresponding temperature range is referred to as the phase inversion temperature range (PIT range).

After the PIT range is known, the process according to the invention can be carried out either by subsequently heating the dispersion initially prepared as usual to a temperature which is within or above the phase inversion temperature range, or in the way that a temperature that is within or above the phase inversion temperature range is selected immediately during the preparation of the dispersion. It is also possible to dilute an anhydrous or low-water concentrate at the phase inversion temperature with hot or cold water (hot-hot or hot-cold process).

Wax dispersions, such as those obtained by the process according to the invention, are used in cosmetics, for. B. as a skin and body care product. The method according to the invention is particularly preferably suitable for the preparation of preparations for skin and hair treatment. In addition, the wax dispersions according to the invention are also suitable for textile finishing, in particular for finishing (finishing).

The following examples serve to illustrate the invention and are not to be understood as restrictive. Examples

1. Substances used a) solid waxes (A)

W-l: paraffin wax ("Paraffin 5213"; Fa ter-HELL)

W-2: stearyl stearate ("Loxiol G41"; Fa. Henkel / Düsseldorf) b) dispersants (B)

D-1: adduct of 10 moles of ethylene oxide with a C22 fatty alcohol ("Mergital BIO"; Sidobre Sinnova)

D-2: adduct of 40 moles of ethylene oxide with a Ciö / ig fatty alcohol ("Disponil TA40"; Henkel / Düsseldorf) c) co-dispersants (C)

CoD-1: glycerol monostearate ("Cutina GMS"; Fa. Henkel / Düsseldorf) d) liquid oils (D)

Oil: iso-tridecyl palmitate / stearate ("Loxiol G40"; Fa. Henkel / Düsseldorf)

2. Preparation and characterization of the dispersions

2.1. Preparation of the dispersions (customary procedure)

A mixture of components (A) to (C) and water was heated to a temperature slightly above the melting point of the mixture and homogenized. The composition of the dispersions is shown in Table 1.

2.2. Preparation of the dispersions according to the invention

The dispersions were, as in 2.1. prepared and then briefly (about 1 minute) heated to 95 ° C. Then the dispersions were rapidly, i. H. at a cooling rate of about 2 ° C per minute, cooled to room temperature with stirring.

2.3. Determination of the phase inversion temperature

The electrical conductivity of the emulsions as a function of the temperature was determined using a conductivity measuring bridge (from Radiometer / Copenhagen). For this purpose, the dispersions were first cooled to + 20 ° C. At this temperature, they showed a conductivity of over 50 microsiemens per cm. By slowly warming up with a A heating rate of approx. 0.5 ° C / min, which was controlled with the aid of a temperature programmer in connection with a cryostat, a conductivity diagram was created. The temperature range within which the conductivity dropped to values below 5 microsiemens per cm was noted as the phase inversion temperature range.

2.4. Assessment of the emulsions

The phase inversion temperatures (PIT) of the compositions of Examples B1 to B7 and VI are shown in Table 2.

The viscosity of the compositions according to Table 1 was determined at 25 ° C. using a Brookfield rotary viscometer at 20 revolutions per minute; Depending on the viscosity range, one of the spindles 3, 5 or 7 was used. The results of the viscosity measurements can be found in Table 2.

Table 2 also provides information on the appearance of the dispersion. The blue appearance of the dispersions according to B1 to B7 indicates particle sizes below 1 micrometer, that is to say that the dispersions are particularly fine.

Table 1: Composition of the dispersions

Table 2: Characterization of the dispersions

Dispersion Viscosity Appearance PIT range (Pas) (° C)

Bl 0.7 blue dispersion 80 - 88 B2 11.0 blue dispersion 80 - 88 B3 64.0 blue dispersion 80 - 88 B4 0.5 blue dispersion 80 - 88 B5 4.2 blue dispersion 80 - 88 B6 31.0 blue Dispersion 80 - 88 B7 0.7 blue dispersion 75 - 85

VI fixed 2 phases no PIT available

Claims

Patent claims

1. A process for the preparation of wax dispersions, characterized gekennzeich¬ net that

(A) 10 to 80% by weight of a wax

(C) 1 to 30% by weight of a hydrophobic co-dispersant from the group of fatty alcohols with 12 to 22 C atoms or the partial esters of polyols with 3 to 6 C atoms with fatty acids with 12 to 22 C atoms , with the proviso that the ratio of components (B) and (C) is in the range from 0.5: 1 to 20: 1, in the presence of 15 to 85% by weight of water to a temperature above the melting point of the mixture heated from components (A) to (C) and then heating the dispersion obtained to a temperature within or above the phase inversion temperature range - or producing the dispersion directly at this temperature - and then the dispersion to a temperature below the Cooling phase inversion temperature range and optionally further diluted with water.

2. The method according to claim 1, wherein the ratio of components (B) and (C) is adjusted so that the phase inversion temperature of the entire composition is above the melting point of the solid wax and below 100 ° C.

3. Use of the wax dispersions according to claim 1 or 2 in cosmetics, for. B. as a skin and body care product.

4. Use of the wax dispersions according to claim 1 or 2 for textile finishing.