WO1994007975A1

WO1994007975A1 - Free-flowing aqueous alkyl sulphate pastes

Info

Publication number: WO1994007975A1
Application number: PCT/EP1993/002509
Authority: WO
Inventors: Rainer Hofmann; Bert Gruber
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1992-09-25
Filing date: 1993-09-16
Publication date: 1994-04-14
Also published as: KR950703633A; EP0662116A1; DE4232166A1; JPH08501597A

Abstract

The aim of the invention is to provide free-flowing, pumpable aqueous alkyl sulphate pastes with a surfactant content of 30 to 80 per cent by wt. and which have suitable rheological properties but do not contain any additional surfactants to reduce the viscosity. This aim is achieved with surfactant pastes containing 0.5 to 10 % by wt. of unsulphonated fatty alcohols, not more than 0.2 %by wt. of inorganic sulphates plus, optionally, inorganic chlorides. The flow limit of pastes of this kind is at the most 45 Pa at 60 °C and/or the viscosity is at the most 6.5 Pa.s at a shear velocity of 10 s-1 and a temperature of 60 °C.

Description

"Flowable aqueous aikyl sulfate pastes"

The invention relates to flowable and pumpable aikyl sulfate pastes, a process for the production of aikyl sulfate pastes with improved flow properties and the use of such pastes for the production of detergents and cleaning agents.

Anionic surfactants of the alkyl sulfate type, especially those containing alkyl radicals with 16 to 18 carbon atoms, show excellent detergent properties and are used in both liquid and powder detergents.

For the preparation of such agents, one generally starts from aqueous alkyl sulfate pastes. In order to avoid unnecessary mass transport, it is advantageous if the aqueous surfactant pastes have the highest possible solids content. Aikyl sulfate pastes can, however, only be concentrated up to a certain solids content. In addition, such pastes have a non-Newtonian flow behavior. Above a limit of about 55% by weight solids content, the viscosity generally reaches such high values that the pumpability of the surfactant solutions is no longer guaranteed, even at elevated temperatures. For example, aqueous fatty alcohol sulfate pastes with solids contents between 30 and 70% by weight have such high viscosities and flow limits even at ambient temperature that transferring and pumping around are often impossible.

European patent EP 24711 proposes adding polyalkyl ether glycol sulfates as viscosity-reducing additives to surfactant concentrates which are difficult to move. While such compounds are well suited to lowering the viscosity of alkyl ether sulfate, alkyl aryl ether sulfate, alkyl benzene sulfonate and alkyl aryl sulfosuccinate solutions, their performance in the presence of alkyl sulfates, especially linear, primary alkyl sulfates, is often unsatisfactory.

German patent application DE 34 47859 discloses the use of alkanesulfonates as viscosity regulators for highly viscous anionic surfactant concentrates, especially for salts of α-sulfofatty acid esters. German patent application DE 37 18 896 describes the use of alkoxylated alcohols as viscosity regulators for highly viscous alkylbenzenesulfonate concentrates.

German patent application DE 40 32 910 discloses alkyl sulfate pastes with solids contents of 30 to 80% by weight, the flow properties of which are improved by adding sulfonation products of unsaturated fatty acid glyceride esters in amounts of 1 to 50% by weight, based on the solids content of the pastes become.

The object of the invention was to provide aikyl sulfate pastes with high contents of alkyl sulfate, which contain no further surfactants and nevertheless have favorable rheological properties.

It has now been found that the rheological properties such as the yield point and viscosity of aqueous aikyl sulfate pastes can be adjusted in a targeted manner by the type and amount of unsulfonated fatty alcohols, so that the unfavorable flow behavior typical of alkyl sulfates is overcome. This makes it possible to produce aikyl sulfate pastes with high surfactant contents, which are flowable and pumpable even at lower temperatures and low shear rates.

The invention accordingly relates in a first embodiment to an aqueous, flowable and pumpable alkyl sulfate paste with a surfactant content of 30 to 80% by weight, the paste containing unsulfated fatty alcohols in amounts of 0.5 to 10% by weight, inorganic Contains sulfates not above 0.2 wt .-% and optionally inorganic chlorides and the flow limit of the paste at 60 ° C a maximum of 45 Pa and / or the viscosity of the paste at a shear rate of 10 s ~ l and a temperature of 60 ° C maximum 6.5 Pas.

The alkyl sulfates are known anionic surfactants which are generally prepared by reacting aliphatic primary alcohols with a sulfating reagent, for example sulfur trioxide or chlorosulfonic acid. Preferred alkyl sulfates are derived from fatty alcohols with 12 to 22 carbon atoms. Typical examples of this are lauryl alcohol, Myristyl alcohol, cetyl alcohol, stearyl alcohol and behenyl alcohol. A particularly drastic reduction in the paste viscosity is observed in alkyl sulfates which are derived from alcohols having 12 to 18, in particular 14 to 18 or 16 to 18, carbon atoms. The alkyl sulfates can also be derived from technical alcohol mixtures, such as those obtained in the hydrogenation of technical fatty acid ester mixtures of natural origin or from aldehydes from Roelen's oxosynthesis. Alkyl sulfates based on technical coconut or hydrogenated palm kernel cuts are preferred. Preferred pastes contain 40 to 65 wt.%, In particular 45 to 60 wt.

Unsulfated fatty alcohols are primarily linear primary and methyl-branched C12 to C22 ~ fatty alcohols in the 2-position. In particular, it is preferred to use fatty alcohols whose C chain distribution corresponds to the C chain distribution of the fatty alcohol sulfates used. The advantageous viscosity-reducing properties are already achieved when the content of unsulfated fatty alcohols in the pastes is relatively low, preferably 0.7 to 8% by weight and in particular 1 to 5% by weight.

Aikyl sulfate pastes usually contain inorganic salts, especially sulfate, resulting from the production. The amount of these inorganic salts is usually not more than 10% by weight, in particular 2 to 5% by weight, in each case based on the paste. The content of the pastes in sodium sulfate can be, for example, 1 to 3% by weight. In addition, the pastes can contain up to about 1% by weight or 1.5% by weight of sodium chloride. These inorganic salts generally have a viscosity-increasing effect. However, if pastes are produced which contain inorganic sulfates in amounts not above 0.2% by weight and preferably in amounts not above 0.1% by weight, but which contain unsulfated fatty alcohols in the stated amounts, the pastes have the desired rheological properties Properties on. It was particularly surprising that a content of inorganic chlorides, preferably alkali chlorides and especially sodium chloride or potassium chloride, did not adversely affect the rheological properties of the paste influenced, but on the contrary can reduce viscosity. A content of 0.2 to 5% by weight and in particular 0.5 to 2% by weight of alkali metal chloride is preferred.

Such pastes are particularly preferred, the flow limit of which at 60 ° C. is a maximum of 40 Pa and preferably a maximum of 38 Pa and / or the viscosity of the paste at a shear rate of 10 s ^-1 and a temperature of 60 ° C. a maximum of 6 Pas, preferably a maximum of 5 Pas , amount.

For reasons of stability, the pH of the pastes should be at least 9. Preference is given to pH values between 9 and 14, in particular between 10 and 13.

The pastes according to the invention can be prepared, for example, by diluting 90 to 98% by weight aikyl sulfate pastes with water and fatty alcohol and, if appropriate, adding the desired amount of inorganic chloride. It is preferably a paste that is preferably a mixture of either

in particular C14-Cis fatty alcohol sulfate or Cis-Ci _β -fatty alcohol sulfate, or only a fatty alcohol sulfate, which is derived from lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol or behenyl alcohol. However, it is also possible that various pastes of the type indicated are first mixed and then diluted as indicated and, if appropriate, chloride is added. A process is preferred in which a paste produced by a conventional process, which normally contains a surfactant between 30 and 80% by weight, preferably not above 60% by weight, initially contains inorganic salts, in particular of Sodium sulfate, essentially freed, the cleaned paste concentrated to a surfactant content of 90 to 98 wt .-% and then adjusted to the desired surfactant content at temperatures between 60 and 100 ° C with an alkaline solution. The inorganic salts can be removed, for example, by recrystallization with ethanol, the inorganic salts precipitating and being separated, for example being able to be filtered off. The highly concentrated, purified surfactant pastes are then obtained by removing ethanol. The setting of a surfactant content from 30 to 80 wt .-%, preferably from 40 to 65 wt .-% and in particular from 45 to 60% by weight, starting from the cleaned, concentrated paste, is preferably carried out at temperatures from 70 to 90 ° C., with the aid of the alkaline solution, which is preferably an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution pH is adjusted from 9 to 14, preferably from 10 to 13. It is particularly preferred that the pastes are added to the alkaline solution.

If the fatty alcohol content of the pastes produced in this way is less than 0.5% by weight, then the corresponding amounts of fatty alcohol must be added. It is preferred that fatty alcohol is added in such quantities that a fatty alcohol content of 0.7 to 8% by weight and in particular 1 to 5% by weight is set.

In a further preferred embodiment, an inorganic chloride, preferably sodium chloride or potassium chloride, is additionally added in amounts such that a chloride content of 0.2 to 5% by weight, preferably 0.5 to 2% by weight , is set.

The concentrated aikyl sulfate pastes according to the invention have excellent detergent properties. They are therefore preferably used for the production of liquid and solid detergents and cleaning agents, which also include detergents, and for products for hair and body care.

Such liquid agents can easily be prepared by diluting the pastes produced by the process according to the invention with water to the desired active substance concentration. The addition of other constituents customary in such agents, to which in particular builder substances such as zeolites and phyllosilicates, corrosion inhibitors, bleaching agents, bleach activators, optical brighteners, enzymes, graying inhibitors, antimicrobial active ingredients, water-miscible solvents, abrasives, foam stabilizers, Preservatives, colors and fragrances as well as additional surfactants are possible. Examples

A Ci6-Ci8 tallow fatty alcohol sulfate paste (sulfopone ( ^R ) T55, 53% by weight tallow fatty alcohol sulfate, approx. 2% by weight unsulfated fatty alcohol, a maximum of 3% by weight inorganic electrolytes) produced by a customary process (oxidation with sulfur trioxide) such as sodium sulfate and sodium chloride; commercial product of the applicant) was essentially freed from the inorganic electrolytes by recrystallizing three times with ethanol and then concentrated to an approximately 97% by weight surfactant paste which contained less than 1% by weight unsulfated fatty alcohol . This paste was then stirred into an aqueous sodium hydroxide solution while hot, ie above the melting point of the tallow fatty alcohol sulfate, and unsulfated fatty alcohol and sodium chloride were added in quantities such that the resulting pastes Ml and M2 each had 53% by weight tallow fatty alcohol sulfate and M3 54% by weight of tallow fatty alcohol sulfate and the amounts of fatty alcohol or fatty alcohol and sodium chloride given for the agents Ml to M3. The content of sodium sulfate in all 3 agents was less than 0.2% by weight. The pH of the agents was 11 in each case.

Content of the agents Ml to M3 in fatty alcohol and optionally in sodium chloride:

Ml 2% by weight taig fatty alcohol

M2 2% by weight taig fatty alcohol 1% by weight sodium chloride

M3 1% by weight taig fatty alcohol 1% by weight sodium chloride

The rheological properties were measured after a rest period in which the samples were equilibrated and any foam formed. At 60 ° C., the agents M1 to M3 according to the invention had both a lower yield point and a lower viscosity than the commercially available sulfopone ( ^R ) T55 paste (see table).

Table: Flow limits at 60 ° C and viscosities at 60 ° C, shear rate 10 s "l (measurement carried out with a shear stress controlled rotation rheometer Carrimed ( ^R ) CS 100 with P1atte-P1atte measuring system)

Claims

Patent claims

1. Aqueous, flowable and pumpable alkyl sulfate paste with a Tensid¬ content of 30 to 80 wt .-%, characterized in that the paste unsulfated fatty alcohols in amounts of 0.5 to 10 wt .-, inorganic sulfates not above 0.2 wt .-% and optionally contains inorganic chlorides, the flow limit of the paste at 60 ° C a maximum of 45 Pa and / or the viscosity of the paste at a shear rate of 10 s ^-1 and a temperature of 60 ° C a maximum of 6.5 Pas.

2. Composition according to claim 1, characterized in that the content of unsulfated C12-C22 fatty alcohols in the paste is 0.7 to 8% by weight, in particular 1 to 5% by weight, it being preferred that the C chain distribution of the unsulfated fatty alcohol corresponds to the C chain distribution of the fatty alcohol sulfates.

3. Composition according to claim 1 or 2, characterized in that the paste contains 0.2 to 5% by weight, preferably 0.5 to 2% by weight, of alkali metal chloride.

4. Agent according to one of claims 1 to 3, characterized in that the content of the paste

preferably C14-Ci8 fatty alcohol sulfate or cis-cis-fatty alcohol sulfate or C-chain pure fatty alcohol sulfates of this chain length is 40 to 65% by weight, in particular 45 to 60% by weight, the flow limit of the paste being 60 ° C a maximum of 40 Pa and preferably a maximum of 38 Pa and / or the viscosity of the paste at a shear rate of 10 s ~ and a temperature of 60 ° C a maximum of 6 Pas, preferably a maximum of 5 Pas.

5. Composition according to one of claims 1 to 4, characterized in that the pH of the paste is 9 to 14, preferably 10 to 13.

6. A method for producing a paste according to any one of claims 1 to 5, characterized in that one or different 90 to 98 wt .-% aikyl sulfate pastes are diluted with water and fatty alcohol and optionally add the desired amount of inorganic chloride.

7. A process for the preparation of a paste according to any one of claims 1 to 5, characterized in that a paste produced by a conventional process is first freed of inorganic salts, in particular sodium sulfate, substantially, the cleaned paste to surfactant contents between 90 and 98 wt .-% concentrated and then adjusted to the desired surfactant content at temperatures between 60 and 100 ° C with an alkaline solution.

8. The method according to claim 7, characterized in that fatty alcohol is added in the amounts that a fatty alcohol content of 0.7 to 8 wt .-%, preferably from 1 to 5 wt .-%, is adjusted.

9. The method according to claim 7 or 8, characterized in that an inorganic chloride, preferably sodium chloride or potassium chloride, is added in amounts such that a chloride content of 0.2 to 5 wt .-%, preferably from 0.5 to 2 wt .-%, is set.

10. The method according to any one of claims 7 to 9, characterized in that the setting of a surfactant content of 30 to 80 wt .-%, preferably from 40 to 65 wt .-% and in particular from 45 to 60 wt .-%, starting from the cleaned, concentrated paste, is carried out at temperatures from 70 to 90 ° C., with the aid of the alkaline solution, preferably an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution, a pH of 9 to 14, preferably 10 to 13 is set.

11. Use of an aqueous, flowable and pumpable alkyl sulfate paste with a surfactant content of 30 to 80 wt .-%, containing unsulfated fatty alcohols in amounts of 0.5 to 10 wt .-%, inorganic sulfates not above 0.2 wt .-% and optionally inorganic chlorides, for the production of liquid and solid washing or cleaning agents.