Method for Scouring Wool
The present invention provides for a method for scouring wool by contacting the wool with an aqueous composition comprising an alcohol alkoxylate, water, and optional additives such as hydrotropes serving as stabilizer and/or dispersant. The compositions were found to exhibit both high detergency in wool scouring, and high stability when stored at room temperature or a lower temperature, while still remain lanolin recovery rate at a high level.
This invention relates to a method for scouring wool, specifically relates to a method for scouring wool with a composition comprising an alcohol alkoxylate.
BACKGROUNDWool straight off a sheep, known as “greasy wool” or “wool in the grease”, contains a high level of lanolin, as well as dirt, dead skin, sweat residue, pesticide, and vegetable matter. Before the wool can be used for commercial purposes, it must be scoured via a process of cleaning the greasy wool. Scouring may be as simple as a bath in warm water, or as complicated as an industrial process using detergent and alkali, and specialized equipment.
Lanolin removed from wool is valuable, for example, it is widely used in cosmetic products such as hand creams. Typically, lanolin is extracted by washing the wool in hot water with a special wool scouring detergent to remove dirt, wool grease (crude lanolin), suint (sweat salts), and anything else stuck to the wool. The wool grease is continuously removed during this washing process by centrifugal separators, which concentrate it into a wax-like substance melting at approximately 36˜42° C. (96˜108° F.).
Like many natural products, lanolin is complex and variable in composition. For example, a typical high purity grade of lanolin is composed predominantly of long chain waxy esters (about 97% by weight) with the remainder being lanolin alcohols, lanolin acids and lanolin hydrocarbons. An estimated 8,000 to 20,000 different types of lanolin esters are present in lanolin, resulting from combinations between the 200 or so different lanolin acids and the 100 or so different lanolin alcohols identified so far. Due to lanolin's complex composition of long chain esters, hydroxy esters, diesters, lanolin alcohols, and lanolin acids, it has been always required to develop a detergent that is capable of removing lanolin and impurities from wool efficiently and quickly.
Generally, there are two key criteria in evaluating a detergent used for wool scouring: 1) degreasing efficiency which is usually characterized by whiteness of the cleaned wool and the residual grease on the wool; and 2) lanolin recovery efficiency from the waste water. For a new developed detergent, both the criteria need to be comparable or better to conventional detergents used in the wool scouring industry, whereby it is preferred that both quantity and quality, i.e. the absence of contaminants, of the lanolin is optimized to maximize the economic benefits. Moreover, environmental aspects of the proposed detergent will also need to be taken into consideration. Therefore it is preferred to have a highly efficient detergent, so that small quantities of detergent can be used, which is further preferred to be easily biodegraded.
WO 94/00508 disclosed that compounds derived from alkenyl succinic anhydrides having particularly C14 to C22 alk(en)yl groups and/or substituents of functional groups elsewhere around the molecule give materials which have significantly and surprisingly different properties. In particular they perform well as nonionic surfactants, particularly in aqueous systems, having unexpected cloud point properties indicating good performance at elevated temperatures and have good behavior in alkaline conditions. Also the surfactants have good biodegradation properties. End uses for the surfactant were also disclosed, which include wool scouring. It was mentioned that the surfactants are very effective wool scouring surfactants, in particular retaining their activity well after multiple scouring cycles, even when used in scouring wool with very fine fibers. The reference disclosed the particular surfactants with good performances in wool scouring, yet did not focus on a composition which includes the surfactants and using such specific combinations as detergent for wool scouring process.
WO 99/16942 disclosed a method of scouring and chemically processing wool or other like fiber in a modified scour in order to produce scoured fibers greatly improved in respect of a number of important quality parameters. Generally, the method involved a series of processes to have fibers such as wool subjected to acid extraction, bleaching, chemical reduction, and treatments with detergents and dispersant step by step, wherein a nonionic detergent was used for scouring the fibers, a low foaming nonionic detergent together with a dispersing agent and an optional reducing agent was used for extra scouring the fibers, and EDTA together with sulphuric acid and optional reducing agent was used for iron extraction from the fibers. The method is a complex process which is a combination of different treatment steps, wherein different chemicals are used for the different treatment steps, respectively.
DESCRIPTION OF THE INVENTIONThe present invention provides for a method for scouring wool with a composition comprising an alcohol alkoxylate. The composition is capable of degreasing wool at a relatively lower dosage, and of removing lanolin or grease from the wool more quickly. Moreover, the composition has excellent storage stability, which overcomes some of the storage problems observed with conventional detergents.
The present invention developed a series of wool scouring detergents based on an aqueous composition comprising an alcohol alkoxylate, water and optional additives including, but not limited to, quaternary ammonium compounds serving as hydrotrope, polymeric dispersants for suspending dirt particles and for preventing stain re-deposition, chelate agents for chelating metal ions such as Ca2+, Mg2+, and fillers for improving antifreeze stability of the formulation and for modifying the rheology of the product. The compositions according to the present invention were found to exhibit both high detergency in wool scouring, and high stability over wide temperature range, along with an increase in the lanoline recovery efficiency and purity.
According to the present invention, the alcohol alkoxylate used as the surfactant is in the form of an alcohol alkoxylate mixture with the following general formula (I):
RO(AO)n—H (I)
Wherein R represents linear or branched hydrocarbyl group having 4 to 22 carbon atoms; preferably having 6 to 13 carbon atoms; more preferably having 9 to 11 carbon atoms.
AO represents a C2-C6 alkyleneoxy unit, n is from 1 to 20, preferably from 2 to 9, more preferably from 4 to 7. “n” means the moles of alkyleneoxy unit addition per mole of the surfactant of formula (I), which is an average value.
The solubility of the detergent and its ability to emulsify lanolin are related to the HLB value of the alcohol alkoxylates used in the composition. Unless otherwise indicated in the present invention, the HLB value is calculated according to Davies scale (0-40), for both cationic and nonionic surfactants mentioned in the present invention. Generally, the length of both the hydrophobic alkyl chain and the hydrophilic alkyloxy chain of alcohol alkoxylates determines the resulting HLB value of alcohol alkoxylates. Preferably the alcohol alkoxylates used in the present invention have an HLB of from 10.0 to 15.0. In addition, by including alcohol alkoxylates with alkyloxy chain as defined above, the cloud point of the resulting wool scouring composition is kept within a range such that the alcohol alkoxylates remain stable during the wool scouring process, while become cloudy or phase separated when the temperature is raised to or above the temperature for lanolin recovery. This is because the alcohol alkoxylates do not behave as an effective emulsifier at a temperature higher than the cloud point. As a result, easier demulsification of lanolin was found to be achieved in lanolin recovery process. Moreover, the alcohol alkoxylates with relatively short hydrophilic alkyloxy chain according to the present invention were found to have improved biodegradation properties in comparison with those having longer hydrophilic alkyloxy chain, and they are therefore more environmental friendly.
Surprisingly, it has also been found that the alkyleneoxy units distribution in the alcohol alkoxylate showed great influence on lanolin detergency and recovery. Specifically, when alcohol alkoxylates of narrow range alkyleneoxy units distribution were used as surfactant in the detergent composition of the present invention, they were observed to result in more effective detergency, and more complete separation of lanolin than those observed with broad range distribution of alkyleneoxy units.
The alcohol alkoxylate used according to the present invention is a mixture which inherently include residue of unreacted alcohol, alcohol alkoxylates with low addition of alkyleneoxy unit, as well as alcohol alkoxylates with excessively high addition of alkyleneoxy unit. Without wishing to be bound by existing theory, it was seen that the residue of unreacted alcohol and alcohol alkoxylates with low addition of alkyleneoxy unit may result in unwanted odor of the degreased wool, and that the alcohol alkoxylates with excessively high addition of alkyleneoxy unit may adversely increase cloud point of the mixture alcohol alkoxylates, for example, to a temperature above the lanolin recovery temperature, which decreases lanolin recovery efficiency.
When used herein, the term “narrow range” means the alcohol alkoxylate for use in the composition has a narrower distribution of the moles of alkyleneoxy addition than a normal alcohol alkoxylate, i.e., “broad range” alcohol alkoxylate. Specifically, the narrow range alcohol alkoxylate used in the present invention has a distribution of the moles of alkyleneoxy units addition not greater than 20, preferably not greater than 9, and more preferably not greater than 7, meanwhile the moles of alkyleneoxy units is preferably not less than 2, and more preferably not less than 4. One of ordinary skill in the art would understand that, due to the preparation process of alcohol alkoxylates, the final product is actually in the form of a mixture of alcohol alkoxylates having different moles of alkyleneoxy units addition, as well as low content of raw material such as unreacted alcohols. For normal processes using KOH, NaOH or the likes as the alkoxylation catalyst to produce alcohol alkoxylates, the distribution of the moles of alkyleneoxy units addition is broad; and for specific processes such as, for example, the process according to EP 0845449 B1 filed by AKZO NOBEL N.V. on Nov. 24, 1997, narrower distribution of the moles of alkyleneoxy units addition was achieved than those obtained with normal processes.
According to the present invention, the narrow range mixture of alcohol alkoxylates is such that, not less than 40 wt %, preferably not less than 60 wt %, more preferably not less than 70 wt %, of the alcohol alkoxylates has a distribution of the moles of alkyleneoxy units addition not greater than 20, preferably not greater than 9, and more preferably not greater than 7, meanwhile the moles of alkyleneoxy units addition is preferably not less than 2, and more preferably not less than 4.
The alcohol alkoxylate used in the composition according to the present invention are advantageously presented as aqueous solution. As discussed above, the cloud point of the composition according to the present invention is kept relatively low, which is actually close to room temperature. Therefore, when at room temperature or a higher temperature that is usually applied in either wool scouring process or lanolin recovery process, it is easy for the composition of the present invention to turn hazy or be further separated into two phases of alcohol alkoxylate and water, depending on the characteristic of different alcohol alkoxylates used in the composition. To stabilize the formulation at a high temperature such as the wool scouring temperature of 65-70° C., a hydrotrope is required to be further added into the composition, to solubilize the nonionic surfactant and to enhance the wetting ability of the composition, such that the otherwise insoluble nonionic surfactant is dissolved in the solution and may exert its wetting ability. A number of hydrotropes for nonionic surfactants have been described in various publications. Generally, the hydrotrope suitable for use in the detergent composition of the present invention should be efficient in solubilizing non-ionic surfactants according to above formula (I).
According to the present invention, the hydrotropes are further selected, so as to minimize or eliminate the adverse effects of hydrotropes on the formulation, such as additional foaming, decreased lanolin recovery, etc. Example of such a hydrotrope includes, but is not limited to, bis(ethoxylated) monoalkyl quaternary ammonium compound having the formula (II),
wherein R is C6-C22 hydrocarbyl, preferably C6-C22 alkyl or alkenyl, more preferably C8-C20 alkyl or alkenyl, and most preferably C10-C18 alkyl or alkenyl; R1 is C1-C4 alkyl, preferably methyl or ethyl, and most preferably methyl; x is a number from 1 to 40, y is a number from 1 to 40 with the provision that x+y is at least 8, preferably at least 9, and most preferably at least 10, and at most 25, preferably at most 20, and most preferably at most 17; A− is an anion, e.g. halide or methylsulfate. The value for individual x and y is not critical, however, the combined total is critical as this effects the HLB of these compounds. Preferably the ammonium compounds useful in the present invention have an HLB of 25.0-31.0 and are very efficient hydrotropes for nonionic surfactants, therefore they aid in the cleaning performance of compositions where they are present in combination with nonionic surfactants.
When used in the composition of the present invention, the weight ratio between the alcohol alkoxylate and the bis(ethoyxlated) monoalkyl quaternary ammonium compound is from 99:1 to 60:40, and preferably from 90:10 to 70:30.
The composition according to the present invention is designed to be diluted in an aqueous system. As the wool varies vastly in grease level and contamination compositions, the concentration of the detergent in the final use solution can be adjusted accordingly. Specifically, the total amount of the alcohol alkoxylate of formula (I) and, if present, the hydrotrope of formula (II) in said aqueous system is greater than 10 ppm, and less than 1000 ppm, preferably greater than 100 ppm, and less than 1000 ppm.
In one aspect of the present invention, a method for scouring wool is provided. The method comprises contacting the wool with a composition comprising alcohol alkoxylates with the general formula (I).
According to one of the embodiments of the present invention, the alcohol alkoxylates used in the composition of the present invention have a narrow range distribution of alkeleneoxy units, wherein not less than 40 wt %, preferably not less than 60 wt %, more preferably not less than 70 wt %, of the alcohol alkoxylates has a distribution of the addition of alkyleneoxy units not greater than 20, preferably not greater than 9, and more preferably not greater than 7, meanwhile the addition of alkyleneoxy units is preferably not less than 2, and more preferably not less than 4.
According to one of the embodiments of the present invention, the alcohol alkoxylates having the general formula (I) are selected from alcohol ethoxylates, alcohol propoxylates, or a combination thereof, wherein AO represents ethyleneoxy unit, propyleneoxy unit, or a combination thereof, R and n being the same as defined above. In the case of the combination of alcohol ethoxylates and alcohol propoxylates, the addition of ethylene oxide units is on average within the range of 2-9, the addition of propylene oxide unit is on average within the range of 0-5.
According to one of the embodiments of the present invention, a hydrotrope selected from bis(ethoxylated) monoalkyl quaternary ammonium compound having the formula (II) is included in such an amount that the weight ratio between the alcohol alkoxylate of formula (I) and the bis(ethoyxlated) monoalkyl quaternary ammonium compound of formula (II) is from 99:1 to 60:40, and preferably from 90:10 to 70:30.
According to one of the embodiments of the present invention, the composition according to the present invention is designed to be diluted in an aqueous system to such a concentration that, the total amount of the alcohol alkoxylate of formula (I) and, if present, the hydrotrope of formula (II) in said aqueous system is greater than 10 ppm, and less than 1000 ppm, preferably greater than 100 ppm, and less than 1000 ppm.
In addition to the above-mentioned components, the composition may also contain other optional additives, such as alkyl glucoside, alkyl sulphate, alkyl ether sulphate, etc. Moreover, the composition may also contain polymeric dispersing agents, chelates, enzymes, pH-controlling agents, bactericides, perfumes, colorants and rheology modifiers, and other components usually appearing in cleaning concentrates.
In yet another aspect of the present invention, the use of the composition according to the present invention is provided. Generally, but not for the purpose to limit the present invention into a specific scope, the composition according to the present invention may be used as a detergent in wool scouring processes and/or lanolin recovery.
The advantages achieved by the composition of the present invention are as follows:
1) By using alcohol alkoxylates with low number of alkylene oxide units per molecule, the composition of the present invention exhibits excellent cleaning efficiency, as compared to conventional detergents used for wool scouring.
2) The composition of the present invention may result in better lanolin recovery. As mentioned above, the alcohol alkoxylates with low number of alkylene oxide units per molecule, while form stable emulsions with lanolin under scouring process, fail to emulsify lanolin in the recovery process where temperature higher than the cloud point is usually applied. Consequently the emulsion break and alcohol alkoxylates may release much more lanolin compared to their higher numbers of alkylene oxide units counterparts.
3) The composition of the present invention exhibits excellent product stability. It may be stored for a long period without clouding or being phase-separated, even during the winter time at those cold areas.
The above and other objectives, features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in embodiments thereof with reference to the accompanying drawings.
The following examples are offered to illustrate, but not to limit the claimed invention. Unless otherwise specified, all percentages are by weight.
EXAMPLE 1Detergent formulations with compositions specified in Table 1 were made. The quanternary ammonium compound was added as a hydrotrope to stabilize the formulation at elevated temperature and to assist cleaning.
To evaluate the cleaning efficiency of the formulations in Table 1 the following wool scouring test was used. Three 800 gram hot (65-70 C) baths were prepared with only the 2nd one containing the detergent blend (0.01%) while the rest two having just tap water. The dirty raw wool (20 gram) was subsequently washed (5 minutes in each bath), squeezed dry, and transferred to one bath after another. The process was designed to mimic the simplified wool scouring process with the 1st bath for suint deposition, the 2nd one primarily for wool cleaning, and 3rd one for rinsing.
The detergent efficiency was evaluated based on the whiteness of the wool after rinsing and drying, and was summarized in
Comparing the detergency results with #1, #2, #3, #4, it is evident that the increasing concentration of hydrotrope improves the whiteness of washed wool. When the blend is composed of 30% of hydrotrope, the whiteness of the washed wool is comparable to that of the wool washed by NP-9. As the detergency efficiency of the nonionic surfactant is constrained by its cloud point which is correlated with the concentration of hydrotrope, this set of scouring results demonstrate that hydrotrope concentration is critical to achieve the optimal detergency efficiency.
EXAMPLE 2Hydrotrope Test
In this example formulations were made with a number of hydrotropes specified in Table 2 to compare hydrotrope efficiency. The less amount of hydrotrope needed to add to turn the formulation to clarity at room temperature, the more effective it is as a solubilizing agent. The numbers in the Table 2 are expressed in wt. %, and water is added to balance the total to 100%.
Lanolin Recovery Efficiency Test
In order to compare lanolin recovery efficiency, a series of formulations with 1.00 g detergent, 8.00 g H2O and 0.50 g lanolin were mixed well, and pictures were taken to characterize the demulsifying process at 70° C.
As shown in
Lanolin was enriched in the nonionic surfactant layer which appears as light amber color. The results show that C9-11-alcohol+4EO (narrow range ethoxylate)started demulsifying within 5 minutes, while the rest didn't start demulsifying until half hour. C9-11-alcohol+4EO and C9-11-alcohol+5.5EO (both narrow range ethoxylate show more complete separation than the rest. These results clearly demonstrate that narrow range alcohol ethoxylates with lower numbers of EO addition have advantages over their normal range counterparts in lanolin recovery. Nonylphenol+9EO in comparison shows little if any lanolin enrichment layer but has all the lanolin well soluablized in the aqueous layer instead.
EXAMPLE 4 Low Temperature Stability TestAs the detergent is usually pumped to the washing bath, it is important to study the stability of the detergent under the cold condition. A series of detergent blends with the compositions listed in Table 3 were mixed, and the phase behavior was observed after the blends were stored overnight at 2 degree C. and −22 degree C.
All five blends appeared clear one phase liquid at room temperature. They turned to hazy translucent liquid under 2 degree C. overnight. No phase separation was observed in any of them. They turned to white solid under −22 degree C. overnight without phase separation. It is worth noting that there was no gelling or precipitation happening for these blends under cold temperature (2 and −22 degree C.), and all samples when taken out of the cold temperature were able to restore to clear one phase liquid without any shaking or mixing when left at room temperature. This study demonstrates that these detergent blends exhibit excellent stability under low temperature. Therefore they are suitable for use during the winter time at those cold areas.
Claims
1. A method for scouring wool, comprising contacting the wool with an aqueous composition comprising an alcohol alkoxylate with the following general formula (I):
- RO(AO)n—H (I)
- wherein R represents linear or branched hydrocarbyl group having 4 to 22 carbon atoms, AO represents an alkyleneoxy unit having 2 to 6 carbon atoms, n is within the range from 1 to 20, and not less than 40 wt % of the alcohol alkoxylates has a distribution of the addition of alcohol alkyleneoxy units ranging from 2-20.
2. A method according to claim 1, wherein not less than 40 wt % of the alcohol alkoxylates has a distribution of the addition of alcohol alkyleneoxy units ranging from 4-9.
3. A method according to claim 1, wherein not less than 40 wt % of the alcohol alkoxylates has a distribution of the addition of alcohol alkyleneoxy units ranging from 4-7.
4. A method according to claim 1, wherein AO is selected from ethylene oxide units, propylene oxide units, or a combination thereof.
5. A method according to claim 3, wherein AO is selected from the combination of ethylene oxide units and propylene oxide units, with the addition of ethylene oxide units being within the range of 2-9, and the addition of propylene oxide units being within the range of 0-5.
6. A method according to claim 1, wherein R represents linear or branched hydrocarbyl group having 4 to 22 carbon atoms.
7. A method according to claim 1, wherein R represents linear or branched hydrocarbyl group having 6 to 13 carbon atoms.
8. A method according to claim 1, wherein R represents linear or branched hydrocarbyl group having 9 to 11 carbon atoms.
9. A method according to claim 1, wherein the composition further comprises a hydrotrope selected from bis(ethoxylated) monoalkyl quaternary ammonium compound having the formula (II), wherein R is C6-C22 hydrocarbyl, preferably C6-C22 alkyl or alkenyl, more preferably C8-C20 alkyl or alkenyl, and most preferably C10-C18 alkyl or alkenyl; R1 is C1-C4 alkyl, preferably methyl or ethyl, and most preferably methyl; x is an number from 1 to 40, y is a number from 1 to 40 with the sum of x+y ranging from 8 to 25; and A− is an anion.
10. A method according to claim 9, wherein the weight ratio between the alcohol alkoxylate of formula (I) and the hydrotrope of formula (II) is from 99:1 to 60:40.
11. A method according to claim 9 wherein the total amount of the alcohol alkoxylate of formula (I) and, if present, the hydrotrope of formula (II) in said composition is from 10 to 1000 ppm.
Type: Application
Filed: Dec 22, 2014
Publication Date: Jan 12, 2017
Inventors: Xiaoyu Wang (Shanghai), Jianmin Xu (Shanghai), Jinnan Liu (Shanghai)
Application Number: 15/107,172
