Fabric softener active composition

[0001] The invention relates to compositions of active fabric softeners with low content of flammable solvents, low melt viscosity and high melt stability.

[0002] Quaternary ammonium salts containing two hydrophobic long chains of hydrocarbon moieties have found wide application as active agents of fabric softeners. Alkanolamine quaternary ammonium salts esterified with an average of two fatty acid moieties per molecule, commonly referred to as ester quats, have largely replaced earlier alkyl quaternary ammonium compounds due to their biodegradability.

[0003] Bis- (2-hydroxyethyl) dimethylammonium chloride fatty acid dispersers that have been used commercially are difficult to carry clean, because the solid tends to clumping and the alloy has high viscosity at low melting points and unsatisfactory stability at higher melting points. Thus, fatty acid disetryl bis (2-hydroxyethyl) dimethylammonium chloride are usually provided in the form of a molten composition containing at least 13% by mass of ethanol or 2-propanol which has a viscosity at 65 to 75 ° C which is low enough for pumping. However, such compositions have a low flash point, below 30 ° C, and therefore are subject to regulatory restrictions and require additional safety measures during handling.

[0004] WO 2007/026314 suggests replacing a flammable solvent for such compositions with 2 to 40% by mass of a diluent selected from alkyl esters or polyesters, alkyl amides or polyamides, fatty acids, nonionic surfactants or mixtures thereof, and in particular hydrogenated fat from tallow, hydrogenated tallow fatty acid, hydrogenated coconut oil, hydrogenated palm stearin, hydrogenated soybean oil, ethylene glycol distearate, hard soy sucrose ester, cetyl palmitate and pentaerythritol tetracaprylate / tetracaprate as suitable diluents. WO 2007/026314 further suggested the use of an additional coupling agent selected from polyhydric alcohols, partial esters of polyhydric alcohols, nonionic surfactants in an amount of 0.1 to 15% by mass. However, the compositions proposed by WO 2007/026314 have the disadvantage of low molten state stability with respect to dealkylation of the quaternary ammonium salt, which leads to an increase in the free amine ester content during molten transport and transfer. Another important state of the art includes US 2003/0220210 and 98 2007 734.

[0005] Therefore, there is still a need for active compositions for fabric softeners that have low melt viscosity and high melt stability and at the same time have low flammability.

[0006] It has been found that active fabric softener compositions based on bis (2-hydroxyethyl) dimethylammonium chloride fatty acid filters made from fatty acids with a specific chain length and saturation level and a specific molar ratio of fatty acid to amino groups, which contain specific amounts of fatty acid triglyceride with a defined smaller chain length of fatty acid moieties, as well as a specific amount of alcohol selected from ethanol, 1-propanol and 2-propanol, they show an unexpected combination of low melt viscosity, high stability against melted dealkylation and low flammability.

[0007] The invention is therefore directed to an active composition for fabric softening agents comprising

a) from 65 to 95% by mass of bis- (2-hydroxyethyl) dimethylammonium chloride fatty acid ester with a molar ratio of fatty acid moieties to amino moieties from 1.80 to 1.96, average chain length of fatty acid moieties from 16 to 18 carbon atoms and values iodine number, calculated as free fatty acid, in the range of 0 to 50,

b) from 2 to 8% by mass of fatty acid triglyceride with an average chain length of 10 to 14 carbon atoms and iodine value, calculated as free fatty acid, in the range from 0 to 15, and

c) from 3 to 12% by mass of an alcohol selected from ethanol, 1-propanol and 2-propanol.

[0008] The invention is further directed to a method of making such compositions, comprising the steps of

a) reacting a mixture containing 78 to 95% by mass of bis- (2-hydroxyethyl) methylamine fatty acid ester with a molar ratio of fatty acid groups to amino groups from 1.80 to 1.96, average chain length of 16 to 18 fatty acids carbon atoms and iodine value, calculated as free fatty acid, in the range of 0 to 50, from 2 to 9% by mass of fatty acid triglyceride with an average chain length of 10 to 14 carbon atoms and iodine value, calculated as free fatty acid, in the range from 0 to 15, and from 3 to 13% by mass an alcohol selected from ethanol, 1-propanol and 2-propanol with an excess of methyl chloride at a temperature of 60 to 120 ° C to form a reaction mixture, and

b) separating unreacted methyl chloride from the reaction mixture of step a) by distilling off the methyl chloride and alcohol mixture, condensing the alcohol from the methyl chloride and alcohol mixture, and returning the condensed alcohol to the reaction mixture to obtain an alcohol content of from 3 to 12% by mass.

[0009] The invention is further directed to an alternative method of making such compositions, comprising the steps of

a) reacting a mixture containing 88 to 98% by mass of bis- (2-hydroxyethyl) methylamine fatty acid ester with a molar ratio of fatty acid moieties to amine moieties from 1.80 to 1.96, average chain length of 16 to 18 fatty acids carbon atoms and iodine value, calculated as free fatty acid, in the range of 0 to 50, from 2 to 9% by mass of fatty acid triglyceride with an average chain length of 10 to 14 carbon atoms and iodine value, calculated as free fatty acid, in the range from 0 to 15, and from 0 to 3% by mass an alcohol selected from ethanol, 1-propanol and 2-propanol with an excess of methyl chloride at a temperature of 60 to 120 ° C to form a reaction mixture,

b) adding more alcohol to the reaction mixture from step a) to obtain an alcohol content of 3 to 12% by mass, and

c) separating unreacted methyl chloride from the mixture of step b) by distilling off the methyl chloride and alcohol mixture, condensing the alcohol from the methyl chloride and alcohol mixture, and returning the condensed alcohol to the reaction mixture to obtain an alcohol content of from 3 to 12% by mass.

[0010] The active composition of the fabric softener according to the invention contains from 65 to 95% by mass of bis- (2-hydroxyethyl) dimethylammonium chloride fatty acid ester. The composition preferably contains 80 to 90% by mass of the ester.

[0011] The bis- (2-hydroxyethyl) dimethylammonium chloride fatty acid ester contains at least one disester of formula (CH3) 2N⁺(CH2CH2OC (= O) R) 2 Cl^- and at least one monoester of formula (CH3) 2N⁺ (CH2CH2OH) (CH2CH2OC (= O) R) Cl^-wherein R is a hydrocarbon group of the RCOO fatty acid moiety. The bis (2-hydroxyethyl) dimethylammonium chloride fatty acid ester has a molar ratio of fatty acid moieties to amine moieties from 1.80 to 1.96, and preferably from 1.85 to 1.94. The defined molar ratio ensures high fabric softening efficiency in the rinse cycle of the fabric softener.

[0012] The bis (2-hydroxyethyl) dimethylammonium chloride fatty acid ester can be obtained from pure fatty acid or a mixture of fatty acids of formula RCOOH, where R is a hydrocarbon group. The hydrocarbon group may be branched or unbranched, and is preferably unbranched.

[0013] The fatty acid moiety has an average chain length of 16 to 18 carbon atoms and an iodine value, calculated as free fatty acid, in the range of 0 to 50. The average chain length is preferably 16.5 to 17.8 carbon atoms . Preferably, the fatty acid moiety has an iodine value of 1.0 to 50, more preferably 2 to 50, even more preferably 5 to 40, and most preferably 15 to 35. Average

- 4 chain length is calculated based on the weight share of individual fatty acids in the fatty acid mixture. For branched chain fatty acids, chain length refers to the longest consecutive chain of carbon atoms. Iodine value is the amount of iodine in g of double bonds used in the reaction with 100 g of fatty acid, determined by the method of ISO 3961. To provide the required average chain length and iodine value, the fatty acid moiety may be derived from a mixture of fatty acids containing both saturated and unsaturated fatty acids. The unsaturated fatty acids are preferably monounsaturated fatty acids. The bis (2-hydroxyethyl) dimethylammonium chloride fatty acid ester preferably contains less than 6% by mass of polyunsaturated fatty acids. Examples of suitable saturated fatty acids are palmitic acid and stearic acid. Examples of suitable monounsaturated fatty acids are oleic acid and elaidic acid. The cis-trans double bond ratio of unsaturated fatty acid moieties is preferably greater than 55:45, and more preferably greater than 65:35. The fraction of polyunsaturated fatty acids can be reduced by selective tactile hydrogenation, which is a hydrogenation that selectively hydrogenates one double bond in the carrier -CH = CH-CH2-CH = CH- but not double bonds in monounsaturated hydrocarbon groups. Specified average chain length and iodine value are key to achieving high softening performance and low melting point at the same time. If the average chain length is less than 16 carbon atoms or the iodine value is higher than 50, the softening performance will be unsatisfactory, while the melting point of the composition may be too high if the average chain length is greater than 18 carbon atoms.

[0014] The fatty acid moiety may be derived from fatty acids of natural or synthetic origin and preferably derived from fatty acids of natural origin, and most preferably from tallow fatty acid. The required iodine value can be obtained by using a mixture of natural fatty acids that already has an iodine value, for example, tallow fatty acid. Alternatively, the required iodine value can be obtained by partially hydrogenating the fatty acid mixture or the triglyceride mixture with a higher iodine value. In another and preferred embodiment, the required iodine value is obtained by mixing a mixture of fatty acids with a higher iodine value with a mixture of saturated fatty acids. A mixture of saturated fatty acids can be obtained by hydrogenating a mixture of fatty acids containing unsaturated fatty acids or from a mixture of hydrogenated triglyceride, for example hydrogenated vegetable oil.

[0015] The active composition of the fabric softening agents according to the invention further comprises from 2 to 8% by mass and preferably from 3 to 6% by mass of fatty acid triglyceride with an average chain length of fatty acid moieties from 10 to 14 carbon atoms and iodine value, calculated to free fatty acid, in the range of 0 to 15. The average chain length of fatty acid moieties is preferably

- 5 is from 12 to 13.8 carbon atoms. The fatty acid triglyceride is preferably coconut oil or hydrogenated coconut oil, and most preferably refined coconut oil. The specified amount of fatty acid triglyceride and the average chain length of fatty acid moieties are key to achieving a low melting point and low flammability of the fabric softening active composition simultaneously. Surprisingly, a certain amount of fatty acid triglyceride also improves the effectiveness of the rinse cycle softener made from the active fabric softener composition of the invention.

[0016] The active composition of the fabric softening agents of the invention also contains from 3 to 12% by mass, and preferably from 6 to 10% by mass of an alcohol selected from ethanol, 1-propanol and 2-propanol. The alcohol is preferably ethanol or 2-propanol, and most preferably 2-propanol. The determined amount of alcohol is crucial for the simultaneous low flammability of the active fabric softener composition and high melt stability of the composition against dealkylation of the bis- (2-hydroxyethyl) dimethylammonium chloride fatty acid ester. The improvement in stability that can be achieved by the right amount of alcohol appears to be characteristic of chloride salts and has not been recognized in the prior art.

[0017] The combined amount of fatty acid triglyceride and alcohol is preferably from 10 to 15% by mass.

[0018] The active fabric softener compositions according to the invention show a combination of high melt dealkylation stability, low melt viscosity and low flammability. The active composition of fabric softeners containing 86% by mass of tallow fatty acid ester of bis- (2-hydroxyethyl) dimethylammonium chloride, 3% by mass of coconut oil and 9% by mass of 2-propanol has a flash point of 38 ° C determined in accordance with DIN 53213.

[0019] The active composition of the fabric softening agents of the invention can be prepared by mixing bis- (2-hydroxyethyl) dimethylammonium chloride fatty acid ester, fatty acid triglyceride and alcohol in specific amounts. However, the active composition of the fabric softening agents is preferably prepared by one of the two methods of the invention that share the quaternization of bis- (2-hydroxyethyl) methylammonium chloride fatty acid ester with excess methyl chloride in the presence of fatty acid triglyceride and then separating the excess methyl chloride in the presence of alcohol. [0020] The first method of the invention comprises two stages.

[0021] In the first stage, the mixture contains from 78 to 95% by mass of bis- (2-hydroxyethyl) methylamine fatty acid ester, from 2 to 9% by mass of fatty acid triglyceride and from 3 to 13% by mass of an alcohol selected from ethanol, 1-propanol and 2-propanol are reacted with an excess of methyl chloride at a temperature of 60 to 120 ° C, preferably 90 to 110 ° C. The molar amount of methyl chloride is greater than the molar amount of bis- (2-hydroxyethyl) methylamine fatty acid ester, and the molar ratio of chloride

The methyl to bis- (2-hydroxyethyl) methylamine fatty acid ester is preferably from 1.1 to 1.5. The bis- (2-hydroxyethyl) methylamine fatty acid ester has a molar ratio of fatty acid groups to amino groups from 1.80 to 1.96, preferably from 1.82 to 1.92, average chain length of fatty acid groups from 16 to 18 atoms carbon, preferably 16.5 to 17.8 carbon atoms and iodine value, calculated as free fatty acid, in the range from 0 to 50, preferably from 1.0 to 50, preferably from 2 to 50, more preferably from 5 to 40, and most preferably from 15 to 35. The fatty acid triglyceride has an average chain length of fatty acid groups from 10 to 14 carbon atoms, preferably from 12 to 13.8 carbon atoms and an iodine value, calculated as free fatty acid, in the range of 0 to 15 and is preferably coconut or hydrogenated oil coconut oil. The reaction is preferably carried out in a pressure vessel at a total pressure of 1 to 10 bar, preferably 3 to 8 bar. Methyl chloride is preferably added to the mixture of bis- (2-hydroxyethyl) methylamine fatty acid ester, fatty acid triglyceride and alcohol at a rate that avoids pressure increases above a certain upper limit. The reaction is preferably carried out until more than 80%, preferably more than 85%, of bis- (2-hydroxyethyl) methylamine fatty acid ester has reacted. Suitable reaction times range from 2 to 8 hours depending on reaction temperature and pressure.

[0022] In the second stage, the unreacted methyl chloride is separated from the reaction mixture of step a) by distilling off the methyl chloride and alcohol mixture, condensing the alcohol from the methyl chloride and distilled alcohol mixture, and returning the condensed alcohol to the reaction mixture to obtain an alcohol content of from 3 up to 12% by mass in the reaction mixture. The mixture of methyl chloride and alcohol is preferably distilled off at a total pressure of 0.2 to 1 bar. The alcohol is preferably condensed from the mixture of methyl chloride and alcohol in the partial condenser at a temperature between the boiling points of methyl chloride and the alcohol at the pressure used for distillation. All or part of the condensed alcohol may be recycled to the reaction mixture, depending on the alcohol content that is required for the resulting mixture.

[0023] The second method according to the invention comprises three steps and differs from the first method according to the invention in that in the first step the initial mixture contains from 88 to 98% by mass of bis- (2-hydroxyethyl) methylamine fatty acid ester and from 0 to 3% alcohol by mass and by the fact that in an additional stage more alcohol is added to the reaction mixture of the first stage to obtain an alcohol content of 3 to 12% by mass, before carrying out the step of separating unreacted methyl chloride from the mixture.

[0024] Two methods of the invention have the advantage of providing an active composition for fabric softening with a low content of unquaternized bis- (2-hydroxyethyl) methylamine fatty acid ester in short reaction times. Second way

- according to the invention, there is the additional advantage of a low level of formation of by-products from alcohol alkylation and an additional reduced reaction time for the alkylation.

[0025] The invention is illustrated by the following examples, which are not intended to limit the scope of the invention in any way.

Examples [0026] The active fabric softener compositions were made from coconut oil, 2-propanol and tallow fatty acid ester bis- (2-hydroxyethyl) dimethylammonium chloride with an iodine value of 20, calculated as free fatty acid, with a molar ratio of fatty acid groups to amino groups from 1.89 and containing 0.044 mmol / g of bis- (2-hydroxyethyl) methylamine fatty acid ester, 0.041 mmol / g fatty acid bis- (2-hydroxyethyl) methylamine chloride and 0.111 mmol / g fatty acid by mixing the powdered quaternary ammonium salt with the solvents in the amounts given in Table 1 and melting the mixtures.

[0027] Storage stability was determined for fabric softening active compositions that were stored for 5 days at 100 ° C in closed glass bottles.

[0028] Melt viscosity was measured at 90 ° C with a REOLOGICA® StressTech rheometer using 50 mm parallel plates, a plate distance of 1 mm and a shear rate of 1, 10 and 100 s^-1.

Table 1

<td colspan="4">Properties of active compositions for fabric softening</td>

<td>Example</td><td> 1*</td><td> 2*</td><td> 3</td>

<td>Quat fraction: Coconut oil: 2-propanol in mass%</td><td> 92:0:8</td><td> 96:4:0</td><td> 88:4:8</td>

<td>Melt viscosity at 1 s^-1 in mPa * p</td><td> 272</td><td> 13200</td><td> 262</td>

<td>Melt viscosity at 10 s^-1 in mPa * p</td><td> 237</td><td> 9010</td><td> 236</td>

<td>Melt viscosity at 100 s^-1 in mPa * p</td><td> 219</td><td> 2290</td><td> 194</td>

<td>Fraction of dealkylated quat after 5 days storage in 100 ° C in%</td><td> 7,8</td><td> 10,0</td><td> 7,9</td>

<td colspan="4">* Not according to the invention</td>

Dorota Rzążewska Patent attorney