MXPA00003481A - Highly alkaline compositions containing a hexyl glycoside as a hydrotrope - Google Patents

Abstract

The present invention relates to a clear and stable, highly alkaline composition with controlled foaming, containing a high amount of surface active nonionic alkylene oxide adduct and a hexyl glycoside as a hydrotrope. This composition has a very good wetting and cleaning ability and can be used for cleaning of hard surfaces, in a mercerization process and for a cleaning, desizing or scouring process of fibres and fabrics.

Description

HIGHLY ALKALINE COMPOSITIONS CONTAINING A HEXYL GLICOSIDE LIKE A HYDROTHROP DESCRIPTION OF THE INVENTION The present invention relates to a clear and stable, highly alkaline composition with controlled foaming, which contains a high amount of nonionic, surface active alkylene oxide adduct, and a hexyl glycoside as a hydrotrope. This composition has a very good wetting and cleaning ability and can be used to clean hard surfaces, in a mercerization process, and for a process of cleaning, desizing or scouring of fibers and fabrics. Highly alkaline compositions, such as concentrates having a high content of alkaline agents, such as alkali hydroxides, alkaline complexing agents and silicates, and having a pH value above 11, preferably above 13, are frequently used for cleaning hard surfaces, mercerizing, scouring, etc. A good wetting ability combined with a good cleaning effect is essential in the aforementioned applications, which requires the presence of considerable amounts of suitable surfactants to decrease the high surface tension caused by the high amount of electrolytes. It is also important to have a controlled foam formation in these systems. To minimize the cost of transportation, these concentrates should contain quantities of water and other solvents as small as possible. It is also advantageous if the concentrates remain homogeneous during transportation and storage. Since these compositions contain high amounts of electrolytes, such as complexing agents with alkali and / or alkali metal, it is difficult to dissolve large amounts of surfactants, especially nonionic surfactants. Therefore, in order to improve solubility, hydrotropes are frequently added, and the most commonly used hydrotropes are ethanol and sodium xylene or cumene sulfonate. Ethanol is rather efficient, but presents an explosion hazard, and sodium xylene or cumene sulfonate is relatively inefficient at higher levels of surfactant.

If a surfactant that is soluble in aqueous alkaline solutions is used without the addition of a hydrotrope, there will be a problem with too much foam, which requires the addition of a foam depressant. Alkyl glycosides have previously been used in highly alkaline compositions, see for example EP-B1-589,978, EP-A1-638, 685 and US-4, 240, 921. In addition, alkyl glycosides are well known as cleaning agents active in cleaning compositions commonly used, see for example WO 97/34971, US-4,627,931 and EP-B1-075, 995. European Patent EP-B1-589, 978 describes the use of alkyl glycosides of 8 to 14 carbon atoms as surface active auxiliaries in the desalting, bleaching and alkaline scouring of sheet-like, natural and / or synthetic textile materials, threads or fluffs, while European Patent EP-Al-638, 685 refers to a mercerization wetting agent containing, either alone or in combination, an alkyl glycoside of 4 to 18 carbon atoms, an alkyl glycine amide of 4 to 18 carbon atoms and the corresponding sulfonated derivatives. Highly alkaline, liquid-containing cleaning liquids containing an alkyl glycoside or an alkyl glycidyl ether and non-ionic alkylene oxide adducts are described in US Pat. No. 4,240,921. Preferred alkylene oxide adducts are those capable of acting as foam depressants, such as polyoxyethylene / polyoxypropylene block copolymers and cased alcohol ethoxylates. The concentrate contains: a) 10 to 35% by weight of alkali metal hydroxide b) 10 to 50% by weight of a mixture of a first nonionic surfactant which is a polyoxypropylene-polyoxyethylene condense which acts as a foam depressant, and a second nonionic surfactant which is a casted ethoxylated alcohol, together with an alkyl glycoside or an alkyl glycidyl ether, where the weight ratio between the alkyl glycoside or the glycidyl alkyl ether and the first and second surfactants non-ionic aforementioned, is between 5: 1 to 10: 1 and c) the rest of water. These concentrates are used to formulate low foaming cleaning compositions which are useful for example in the food industry. However, the above composition described in US Patent No. 4,240,921 requires a rather high proportion of alkyl glycoside to the other nonionic surfactants present in the composition. Furthermore, it is well known that the inclusion of larger amounts of PO in an alkoxylate, such as in the foam depressants of the Pluronic type, has a negative influence on the biodegradation capacity of the product. Finally, a cased alcohol ethoxylate is usually a poor wetting agent and also has a low cleaning ability. Their presence also increases the need for an extra amount of the alkyl glycoside or the glycidyl alkyl ether. There is consequently a need for highly alkaline compositions with improved properties. It has now been found that highly alkaline compositions have a pH above 11, preferably at least 13 and more preferably above 13.7, which show excellent cleansing and wetting ability, can be prepared by the use of a glycoside of hexyl that has the formula CßHiaOGn (I where G is a monosaccharide residue and n is from 1 to 5, as a hydrotrope for a surface active nonionic alkylene oxide adduct that is insoluble in the highly alkaline composition and contains a hydrocarbon group or an acyl group of 8 to 24 carbon atoms and at least one primary hydroxyl group in the alkoxylated part of the molecule. Suitably, the adduct has the formula R (AO) x (C2H40) and H (II) where R is an alkoxy group R 'O- having from 8 to 24 carbon atoms or a group R "' CONR '' ', where R" is a hydrocarbon group having 7 to 23 carbon atoms, R' '' is hydrogen or a group - (AO) x (C2H40) and H, preferably hydrogen, AO is an alkyleneoxy group having 2 to 4 carbon atoms, x is a number from 0 to 5 and y is a number from 1 to 10.

The present invention also relates to a composition having a pH value above 11, which contains a) from 3 to 50% by weight of alkali metal hydroxide and / or complexing agents, alkaline, b) of 0.05 to 30% by weight of an adduct of nonionic alkylene oxide, active surface, having a hydrocarbon group or an acyl group of 8 to 24 carbon atoms and having at least one primary hydroxyl group in the alkoxylated part of the molecule, c) from 0.04 to 30% by weight of a hexyl glycoside, and d) from 20 to 97% by weight of water. The proportion by weight between the hexyl glycoside and the surfactant according to formula II is from 1:10 to 10: 1, preferably from 1:10 to 4: 1. It should be noted that the alkyl glucosides have been used in less alkaline detergent compositions, where the conditions are different. Examples of such compositions are to be found in U.S. Patent No. 4,488.91 and European Patent EP-B1- 136, 844.

U.S. Patent No. 4,488,981 and European Patent EP-B1-136, 844 describe the use of the alkyl glycosides of 2 to 6 carbon atoms to reduce the viscosity and prevent phase separation in an aqueous liquid detergent, for example in liquid shampoos and soaps and in heavy-duty liquids. The alkyl glycosides of 2 to 4 carbon atoms are the most preferred alkyl glycosides, since these are more effective in reducing viscosity. In addition, US Patent No. 5,525,256 and Statutory Invention H 468 disclose liquid, alkaline, industrial and institutional cleaning compositions containing alkyl glycosides of 8 to 25 carbon atoms as cleaning agents. However, none of these references describe the unexpected effects of hexyl glycosides in highly alkaline cleaning compositions, containing at least 3%, preferably at least 20% alkaline and / or alkaline additives and having a pH value above. of 11, preferably at least 13, and more preferably above 13.7.

Suitable examples of nonionic surfactants according to formula II are alkylene oxide adducts obtained by the alkoxylation of an alcohol or an amide. The group R in formula II can be branched or linear, saturated or unsaturated, aromatic or aliphatic. Examples of suitable hydrocarbon groups R 'are 2-ethylhexyl, octyl, decyl, cocoalkyl, lauryl, oleyl, rapeseed alkyl and bait alkyl. Particularly suitable hydrocarbon groups R 'are those obtained from oxoalcohols, Guerbet alcohols, methyl substituted alcohols, with 2 to 4 groups having the formula -CH (CH3) - included in the alkyl chain, and linear alcohols. Other suitable R groups are the aliphatic amido groups R''CONH-, where R "CO is preferably derived from aliphatic acids such as 2-ethylhexanoic acid, octanoic acid, decanoic acid, lauric acid, coconut fatty acid, oleic acid, fatty acid rapeseed oil and fatty acid bait. The alkali hydroxide in the composition is preferably sodium or potassium hydroxide. The alkaline complexing agent can be inorganic as well as organic. Typical examples of inorganic complex forming agents used in the alkaline composition are alkali salts of silicates and phosphates, such as sodium tripolyphosphate, sodium orthophosphate, sodium pyrophosphate, sodium phosphate and the corresponding potassium salts. Typical examples of organic complexing agents are alkaline aminopolyphosphonates, organic phosphates, polycarboxylates, such as citrates; aminocarboxylates, such as sodium trilotriacetate (Na3NTA), sodium ethylenediaminetetraacetate, sodium diethylenetriaminepentaacetate, sodium 1,3-propylenediaminetetraacetate, and sodium hydroxyethylethylenediaminetriacetate. The wetting of the composition is attributable to the nonionic surfactant present. Hexyl glycoside is not a wetting agent by itself, but by acting as a hydrotrope for the surfactant, it improves the wetting ability of the composition, since the otherwise insoluble surfactant is now dissolved and can exert its ability to wetting Concentrates with unexpectedly high amounts of surfactants can be dissolved in a highly alkaline aqueous phase, and the amount of hydrotrope required to obtain a stable, clear concentrate or composition is lower than in the prior art. This is very surprising, since in formulations with other short chain alkyl glycosides, it is not possible to include such large amounts of nonionic, surface active alkylene oxide adducts, as when the n-hexyl glucoside is present in the formulations For comparison, the formulations have also been made with shorter and longer alkyl glycosides, which are illustrated in Example 1. The composition of the present invention also shows controlled foam formation without the need to add foam depressants. , like those used in the prior art. The products in the composition all have good environmental properties. These are easily biodegradable and have low toxicity. The composition has an excellent wetting and cleaning ability and can be advantageously used for the alkaline cleaning of hard surfaces, for example, cleaning of vehicles, in a mercerization process and for a process of cleaning, desizing or scouring of fibers and fabrics performed at a pH above 11.

When used for cleaning hard surfaces, the composition is usually diluted with water before use, while in a mercerization process, the composition can be used as such. For cleaning, desizing and scouring of fibers and fabrics the composition should be either used as such or diluted. When woven fabrics are produced, the warp yarns are subject to extreme stresses and must therefore be provided with a protective coating - the squeezing agent - which adheres to the fiber, forming an elastic, abrasion resistant film. The two main groups of preparation agents are macromolecular natural products and their derivatives, for example starches and carboxymethylcellulose, and synthetic polymers, for example polyvinyl compounds. The dressing agent must be completely removed when the garment has been woven, as it usually has a damaging effect on the subsequent finishing processes. The sizing process can be enzymatic or oxidative, and is usually carried out to completion in the subsequent alkaline blanching and scouring stages, where the starch degradation products initially insoluble in water, and the residual binders are partially broken from hydrolitically and partially oxidatively, and eliminated. During the scouring, the intra- and intermolecular hydrogen bonds of the cellulose are broken, and the polar hydroxyl groups of the polysaccharide are solvated. The transport of the impurities from the internal part to the outer part of the fiber occurs then. In the alkaline environment the hydrolytic decomposition of the different plant parts and fats takes place and the waxes are also hydrolyzed. The alkali concentration used is approximately 4 to 6% when NaOH is used. In the scouring process there is a need for auxiliaries, to effect perfect wetting, emulsification and dispersion of insoluble impurities in water, formation of complexes of heavy metal ions and prevention of damage to the fiber by oxygen atmospheric. Here, alkali-stable wetting agents and detergents are an important group of additives. It is also very important that an adequate amount of wetting agent / detergent be soluble in the aqueous alkaline solution, which frequently requires the addition of a hydrotrope. The same applies to an even greater degree for the mercerization process, which is mainly carried out in order to improve the dyeing capacity of cotton. The process involves treating cotton under tension with approximately 20 to 26% caustic soda solution at 15 to 25 ° C for 25 to 40 seconds. This treatment destroys the spiral shape of cellulose, which improves the accessibility of water, and consequently, of water-based dyes. In addition to good wetting ability and alkaline stability, it is also important that the additives do not cause foaming, as this could impede the rapid wetting required in the mercerization baths. The present invention is further illustrated by the following examples.

Example 1 This example illustrates the amount of different hydrotropes of alkyl glucoside R0 (G) n, which is necessary to obtain clear solutions of 5% nonionic surfactant in solutions containing 10, 20, 30 and 40% NaOH. The nonionic surfactant used was an alcohol of 9 to 11 carbon atoms with a linearity above 80% which had been ethoxylated with 4 moles of ethylene oxide per mole of alcohol in the presence of a narrow-field catalyst. The glycosides tested are laboratory samples, except for the butyl glucoside which is a commercial sample of SEPPIC. The degree of polymerization falls between 1.4 and 1.6 with somewhat higher amounts of glucose for the longer alkyl chains.

Process : % non-ionic surfactant was added to aqueous solutions with different amounts of sodium hydroxide. The hydrotropes tested were added dropwise at room temperature to those aqueous mixtures of nonionic and sodium hydroxide in an amount that was just sufficient to obtain a clear solution. no clear solution was obtained, a glycoside based on an alcohol substituted with methyl, containing groups having the formula -CH (CH 3) - included in the alkyl chain.

From the results it is evident that the solubilization effect of the hexyl glucoside is superior to the solubilization effects of the alkyl glucosides used for the comparison.

Example 2 To compare the efficiency of n-hexyl glucoside to other types of hydrotropes, the same procedure as described in Example 1 was followed. no clear solution was obtained The tests show an unexpectedly good solubilization ability of n-hexyl glucoside, especially at high contents of alkaline material.

Example 3 The surface tension was measured according to du Nouy (DIN 53914). The first three solutions contained 5% of the same nonionic that was used in Examples 1 and 2, and the different amounts of the hydrotropes were the same as in Example 2. For the solutions containing only n-hexyl glucoside the amounts were (5 + x)%, where x represents the amounts used in Examples 1 and 2. no clear solution was obtained, and the surface tension was not measured for these formulations.

Example 4 The modified Drave test was used to measure the wetting ability of highly alkaline compositions containing n-hexyl glucoside and non-ionic surfactants, in comparison to n-hexyl glucoside alone. In the modified Drave test, the immersion time in seconds is measured for a specified cotton yarn in approximately 0.1% surfactant solution. In this example, the concentrations for the hexyl glycoside and the non-ionic surfactant specified in the following table were used.

The decyl glucoside is used for a comparison, since it represents an example of a non-ionic surfactant which is soluble in aqueous alkaline solution in the absence of any hydrotrope. As can be seen from the table, n-hexyl glucoside has no ability to wet itself.

Example 5 The contact angle was measured with surfactant solutions, at concentrations specified in the following table, against a hydrophobic polymeric material (Parafilm). The angle is measured with a goniometer 1 minute after the application of the fluid. The decyl glucoside is used for a comparison.

Example 6 The foam is measured as mm of foam produced in a 500 ml measuring cylinder with internal diameter of 49 mm from a solution of 200 ml of surfactant when the cylinder is turned 40 times in one minute. The test is performed at room temperature and the height of the foam is recorded directly and after 1 and 5 minutes.

The decyl glucoside is used for a comparison.

Example 7 The following two formulations were prepared to evaluate the cleaning efficiency of a formulation using n-hexyl glucoside as a hydrotrope, compared to a formulation using sodium eumeno sulfonate as a hydrotrope. 11 This amount was necessary to obtain a clear solution.

The cleaning efficiency of the formulations in the above table was evaluated using the following cleaning test: Plates painted white were daubed with a mixture of oil-soot obtained from diesel engines. 25 ml of the test solutions are emptied onto the top of the plates smeared with oil and left there for one minute. The plates are then rinsed with a rich flow of water. All solutions and water are maintained at a temperature of approximately 15-20 ° C. Both test solutions were placed on the same plate. The reflectance of the plates was measured with a Minolta Chroma Meter CR-200 reflectometer before and after cleaning. The test was carried out with the concentrates and with the solutions diluted 1: 3 with water. Washed dirt was calculated by the computer program built into the meter, whereby for the formulation I according to the invention approximately 85% of washed dirt was obtained and for the reference formulation II about 44% washed dirt was obtained. For the diluted 1: 3 solutions, the corresponding amounts were 68 and 21% respectively. It was also found that, when n-hexyl glycoside is used as a hydrotrope, the hydrophobic powder which is emulsified in the cleaning process can be easily separated from the waste water after dilution with water. This is an important advantage, since there is a growing environmental demand for the low oil content in the wastewater.

Example 8 The following table shows some examples of how much n-hexyl glucoside is needed to obtain a clear solution in water with different types and amounts of non-ionic surfactants, with different amounts of Na3NTA added.

Claims (12)

1. The use of a hexyl glycoside having the formula C6H13OGn (I), wherein G is a monosaccharide residue and n is from 1 to 5, in a highly alkaline composition having a pH value above 11, containing an adduct of nonionic alkylene oxide, surface active, which is not soluble in the highly alkaline composition, and contains a hydrocarbon group or an acyl group of 8 to 24 carbon atoms, and at least one primary hydroxyl group in the alkoxylated part of the molecule, like a hydrotrope.

2. The use according to claim 1, wherein the adduct has the formula R (AO) x (C2H40) and H (II), where R is an alkoxy group R 'O- having 8 to 24 carbon atoms or a group R '' CONR '' '- where R "is a hydrocarbon group having 7 to 23 carbon atoms, R' '' is hydrogen or the group - (AO) x (C2H40) and H, AO is an alkyleneoxy group with 2 to 4 carbon atoms, x is a number from 0 to 5 and y is a number from 10.

3. The use according to claim 1 or 2, wherein the alkaline composition has a pH value above 134.

The use according to claims 1, 2 or 3, wherein the glycoside is an n-hexyl glycoside.

5. An aqueous alkaline composition having a pH value above 11, characterized in that it contains: a) 3 to 50% by weight of alkali metal hydroxide and / or alkaline complexing agents; b) 0.05 to 30% by weight of an adduct of nonionic alkylene oxide, surface active having a hydrocarbon group or an acyl group of 8 to 24 carbon atoms and having at least one primary hydroxyl group in the alkoxylated part of the molecule; c) 0.04 to 30% by weight of a hexyl glycoside; and d) 20 to 97% by weight of water.

6. A composition according to claim 5, characterized in that the nonionic surfactant is an alkoxylate having the formula R (A0) x (C2H4O) and H (II), wherein R is an alkoxy group R '0- having 8 a 24 carbon atoms or a group R "-CONR" '- where R "is a hydrocarbon group having 7 to 23 carbon atoms, R' '' is hydrogen or the group - (AO) x (C2H40) and H, AO is an alkyleneoxy group with 2 to 4 carbon atoms, x is a number from 0 to 5 and e is a number from 1 to 10.

7. A composition according to claims 1-6, wherein the weight ratio between c) and b) is from 1:10 to 4: 1.

8. A composition according to claims 5-7 having a pH value above 13.

9. A composition according to claims 5-8 wherein the hexyl glycoside is n-hexyl glycoside.

10. The use of the alkaline composition according to claims 5-9, in a mercerization process.

11. The use of the alkaline composition according to claims 5-9 in a hard surface cleaning process.

12. The use of the alkaline composition according to claims 5-9 in a process of cleaning, deburring or scouring fibers and fabrics.