Concentrated surfactant composition and use thereof

Abstract

The present invention relates to a concentrated surfactant composition comprising an anionic surfactant represented by chemical formula 1. The surfactant has a structure in which C8 to C18 alkyl groups and 12 to 20 moles of ethylene oxide (EO) are added, and exhibits both excellent contaminant removal capability and low foaming properties (reduction in foam generation). In addition, the composition contains 75 to 95 wt% of the surfactant of chemical formula 1 in the form of a neutralized solid, in which an inorganic salt is adjusted to a range of 0.5 to 3.5 wt%, so that the composition exhibits excellent fluidity and phase stability even at high concentrations. Therefore, the composition has the advantage of maintaining a transparent appearance and stable properties even during long-term storage and distribution.

Description

Concentrated surfactant composition and use thereof

[0001] The present invention relates to a concentrated surfactant composition and its use.

[0002]

[0003] Surfactants are generally designed to generate foam to enhance cleaning effectiveness, but some applications require surfactants designed to minimize foaming. For example, in laundry detergents and personal care products, low foaming and rapid rinsing are important factors for consumer convenience and product performance. In particular, shampoos and cleansing products for pets with thick fur require rapid rinsing after cleaning to reduce residual surfactant and foam.

[0004] Furthermore, in the case of laundry detergents, excessive foam can interfere with the mechanical operation of the washing machine, reducing the efficiency of removing stains from clothing. In particular, in washing machines that utilize mechanical rotational force, such as front-load washers, foam can cause bubble-buffering, reducing washing efficiency.

[0005] Furthermore, the main reason foam remains even after repeated rinsing after washing is the fiber-absorbing nature of the small amount of remaining surfactant. Since most of the typical foam-controlling ingredients (antifoaming agents) are released during the initial rinsing process, the foam-suppressing effect is limited during the second and third rinses.

[0006] Therefore, solving these problems requires molecular design, not simply using additives, but rather manipulating the surfactant's structure to impart superior rinsability and water-soluble properties. Furthermore, maintaining a balance without compromising cleaning power (contaminant removal) is crucial in this structural design.

[0007] Meanwhile, alkyl ether carboxylates can generally be manufactured into highly concentrated products in their acidic form (acid state), but after neutralization, fluidity decreases and gelation occurs, making commercialization of high-concentration products difficult. In particular, when the molar number of ethylene oxide (EO) added is high, the melting point rises and viscosity increases, which reduces fluidity. Therefore, the higher the molar number of EO, the more limited the manufacturing of high-concentration products becomes.

[0008] Theoretically, commercialization is possible as a high-concentration surfactant product at the level of 60% only when the EO added mole number is low, but in the case of alkyl ether carboxylate with a high EO added mole number, commercialization is difficult at a concentration of 20% or more.

[0009] Highly concentrated surfactant compositions are essential not only for reducing transportation and distribution costs, but also as a base material for the manufacture of capsule-type detergents and high-performance laundry detergents. In particular, for capsule-type detergents, surfactants with high moisture content can compromise the stability of packaging films (such as PVA). Therefore, securing a highly concentrated composition with low moisture content and stable viscosity is essential.

[0010]

[0011] The present invention seeks to provide a concentrated surfactant composition that has low foaming, excellent rinsability, and can maintain phase stability and viscosity stability even in a highly concentrated state.

[0012]

[0013] The present inventors have confirmed that an alkyl ether carboxylate compound prepared by adding 12 to 20 mol of ethylene oxide to a fatty alcohol having an alkyl group carbon number of C8 to C18 simultaneously exhibits excellent low-foaming properties and stain removal effects when applied to a laundry detergent. In particular, it was confirmed that even under conditions where the compound is neutralized to prepare a salt form and an inorganic salt such as sodium chloride generated during the manufacturing process is adjusted to remain at a level of 0.5 to 3.5 wt%, a highly concentrated surfactant composition containing a solids content of 75 to 95% can be prepared. In addition, it was confirmed that the highly concentrated surfactant composition prepared in this way maintains a transparent liquid state without phase separation and also maintains excellent fluidity.

[0014] Conventional highly concentrated liquid surfactant compositions have been limited in their processability by requiring the addition of large amounts of water for dilution due to increased viscosity or phase separation, which has resulted in various problems such as reduced production efficiency, deteriorated storage stability, and increased distribution volume. However, the present invention has confirmed that it is possible to produce a concentrated surfactant composition with excellent fluidity and phase stability even at high concentrations when the alkyl ether carboxylate structure is combined with a specific molar number of EO and a certain range of inorganic salts are simultaneously included.

[0015] Accordingly, the present invention aims to provide a concentrated surfactant composition capable of maximizing efficiency in the manufacturing and distribution process while maintaining a high concentration of solid content by precisely controlling the inorganic salt content through a filtering process, a laundry detergent composition including the same, and a method for manufacturing the same.

[0016]

[0017] The present invention relates to a concentrated surfactant composition comprising an alkyl ether carboxylate anionic surfactant represented by chemical formula 1.

[0018] The surfactant compound represented by the above chemical formula 1 is prepared by adding 12 to 20 moles of ethylene oxide to the alkyl group C8 to C18, and has the advantages of low foaming and excellent contamination removal ability.

[0019] In addition, the concentrated surfactant composition contains 75 to 95 wt% of solid content and 0.5 to 3.5 wt% of inorganic salt within the solid content, so it has the advantage of being stable and maintaining fluidity without gelation even in a highly concentrated state.

[0020]

[0021] Figure 1 shows the amount of foaming (mm) according to the molar number of EO (ethylene oxide) added for alkyl ether carboxylate surfactants having alkyl groups of 12 to 14. The amount of foaming significantly decreased when the molar number of EO added was 12 mol or more, indicating that compositions containing 12 mol or more of EO are suitable for low-foaming properties and easy-rinsing laundry detergent products.

[0022] Figure 2 shows the contamination removal power (%) according to the molar number of ethylene oxide added to alkyl ether carboxylate (C12-14). The contamination removal power is excellent when the molar number of EO added is 12-20 mol.

[0023]

[0024] The following describes this specification in more detail.

[0025] This is specifically explained as follows. Meanwhile, each description and embodiment disclosed in the present invention can also be applied to other descriptions and embodiments thereof. In other words, all combinations of the various elements disclosed in the present invention fall within the scope of the present invention. Furthermore, the scope of the present invention is not limited by the specific descriptions described below.

[0026] Expressions such as “comprising” as used herein should be understood as open-ended terms implying the possibility of including other embodiments, unless specifically stated otherwise in the phrase or sentence in which the expression is included.

[0027] The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0028]

[0029] Concentrated surfactant composition

[0030] In one aspect, the present invention provides a concentrated surfactant composition comprising an anionic surfactant represented by chemical formula 1.

[0031] [Chemical Formula 1]

[0032]

[0033] In the above chemical formula 1, m is an integer from 7 to 17, n is an integer from 12 to 20, and X can be H, Na, K, ammonium, or amine.

[0034] Specifically, n is an integer from 12 to 18, and X can be H, Na, K, ammonium, or amine.

[0035] More specifically, m may be an integer from 11 to 13, n may be an integer from 12 to 16, or X may be H, Na, K or an amine.

[0036] The above anionic surfactant is an alkyl ether carboxylic acid prepared by adding 12 to 20 moles of ethylene oxide to a fatty alcohol having an alkyl group of C8 to C18 and subjecting it to a carboxylation reaction, or an alkyl ether carboxylate neutralized by reacting a carboxylating agent with a basic neutralizing agent. When applied to a laundry detergent, it produces little foam (low foaming), is quickly rinsed during the rinsing process, leaves no residual foam, and has excellent contamination removal power.

[0037] The concentrated surfactant composition according to the present invention contains 75 to 95 wt% of the solid content of the surfactant and 5 to 25 wt% of the moisture.

[0038] The above anionic surfactant is contained in a content of 75 to 95 wt%, preferably 75 to 85 wt%, based on the solid content, and the moisture content is adjusted to 5 to 25 wt%. The above solid content refers to the active surfactant, and refers to the effective ingredient that actually performs the surfactant action.

[0039] In particular, the solid content may contain 0.5 to 3.5 wt% of inorganic salts based on 100 wt% of surfactant active ingredients. This exists in the form of inorganic salts such as sodium chloride and potassium chloride generated during the manufacturing process and remaining partially after the filtration process. The content of inorganic salts can be controlled by filtration through a filter with a size of 20 to 400 mesh, which contributes to ensuring flexibility in process control and stability in product quality.

[0040] Additionally, the anionic surfactant may include an inorganic salt containing 0.5 to 3.5 wt% of sodium ions or potassium ions based on 100 wt% of the surfactant active ingredient. Such inorganic salts exist in the form of sodium chloride, potassium chloride, etc., and are naturally generated during the reaction process and remain in the composition.

[0041] The above-mentioned inorganic salt can reduce the electric double layer of the anionic surfactant, shrink the lamellar structure, and compress the molecular alignment, thereby contributing to lowering the viscosity and improving the fluidity.

[0042] As the above-mentioned inorganic salt, an inorganic salt containing a monovalent cation such as sodium or potassium may be used, and an inorganic salt containing a divalent cation such as magnesium may be selected as needed. Specifically, a monovalent cation inorganic salt such as sodium chloride or potassium chloride may be used, and a divalent cation inorganic salt such as magnesium chloride may also be used as needed. In particular, it was confirmed that when the composition contained 0.4 to 2.8 wt% of sodium chloride or potassium chloride under the condition that the solid content of the surfactant was about 80 wt%, the composition became transparent and the long-term storage stability was improved. The content of the above-mentioned inorganic salt can be controlled by a filtration process using a filter having a size of 20 to 400 mesh, and this can be implemented in a manner that some of the salts generated by the carboxylation reaction during the manufacturing process are filtered and retained. The above surfactant is a neutralized surfactant containing 0.5 to 3.5 wt% of an inorganic salt. The inorganic salt is included by selectively removing and controlling the residual amount of salts such as sodium chloride and potassium chloride generated during the reaction through a filter with a size of 20 to 400 mesh. The concentration of the inorganic salt induces the formation of a lamellar structure of the surfactant, thereby contributing to lowering viscosity and improving fluidity. However, since negative effects such as phase separation or increased viscosity may occur depending on the type and concentration of the inorganic salt, it is important to control the content within an appropriate range. In the present invention, 0.4 to 2.8 wt% of the inorganic salt was left on the basis of 80 wt% of the solid content (0.5 to 3.5 wt% based on 100 wt% of the active ingredient). It was confirmed that when the amount exceeds 3.5 wt% based on 100 wt% of the active ingredient, there is a risk of precipitation due to decreased solubility in water.

[0043] Despite their high solids content, these concentrated surfactant compositions maintain a clear liquid state without phase separation. They also exhibit excellent fluidity, exhibiting a viscosity of 500 to 13,000 cPs at room temperature. This facilitates handling during pumping, filling, and packaging processes, and ensures superior cleaning power and ease of use when applied to end-user products.

[0044] Furthermore, this composition can be applied to personal care products, pet shampoos, cleansing products, and more, in addition to laundry detergents. It can be widely utilized in a variety of product groups that simultaneously require low foaming, high cleaning power, and rapid rinsing properties. In particular, its highly concentrated composition offers advantages such as high transport and storage efficiency, and it offers environmental friendliness and economical benefits compared to low-concentration, diluted products.

[0045] The surfactant of the above chemical formula 1 has low-foaming properties, which significantly reduce the amount of foam generated and improve rinsability after washing when the added mole number of ethylene oxide is 12 or more. Specifically, it has excellent low-foaming properties when the added mole number of ethylene oxide is 12 to 20. In addition, the surfactant of the above chemical formula 1 has the characteristic of maintaining excellent contamination removal ability when the added mole number of ethylene oxide is 12 to 20.

[0046] In addition, the composition maintains phase stability and viscosity stability for more than 30 days at room temperature, and the viscosity at room temperature is 500 to 13,000 cPs. More specifically, the phase stability and viscosity stability within the above range are maintained for 30 days to 2 years. The concentrated surfactant composition of the present invention must be stored and distributed in a liquid state (liquid) for the convenience of the user, and generally, the surfactant concentration for maintaining the liquid state must be a low concentration of 24% or less to ensure fluidity. However, such a low-concentration composition has a high water content, so it is disadvantageous in terms of economic feasibility because it incurs manufacturing costs, packaging costs, and transportation costs that are about three times or more compared to 80% raw materials.

[0047] Accordingly, in the experimental examples of the present invention, tests were performed under various solid concentration conditions including inorganic salts in order to produce a surfactant composition having both transparency and fluidity at high concentrations. As a result, when the solid content of the surfactant was 20% or less, the viscosity was very low, but when the solid content increased to 30% or more, the arrangement of the surfactant molecules converted to a liquid crystal state, causing a rapid increase in viscosity, and at a certain concentration, gelation occurred, making viscosity measurement impossible. However, when the solid concentration was further increased, the viscosity tended to decrease again as the surfactant formed a lamellar structure, and the viscosity decrease phenomenon was particularly noticeable in the section where the solid content was around 80% (Table 1). In addition, in order to precisely confirm the viscosity characteristics at a concentration where the surfactant solid content is around 80%, alkyl ether carboxylates with C12-C14 alkyl groups and 15 mol of ethylene oxide were manufactured by gradually changing the solid content from 75% to 85%. At this time, sodium chloride was used as the inorganic salt, and it was adjusted to remain at a level of 2.0 wt% based on the surfactant active content. As a result of viscosity analysis of the manufactured composition, it was confirmed that when the solid content was in the range of about 76% to 83%, the surfactant formed a lamellar structure and the viscosity decreased rapidly. This suggests that the corresponding range is an appropriate concentration condition for simultaneously securing the fluidity and transparent liquid properties of the surfactant (Table 2).

[0048] Furthermore, in the present invention, alkyl ether carboxylate was synthesized by reacting a carboxylating agent (monochloroacetic acid) with an alcohol ethoxylate. The inorganic salt (sodium chloride) produced during this process was partially removed by filtration, and the remaining portion was controlled by remaining within the alkyl ether carboxylate. The surfactant manufactured in this neutralized form was confirmed to have excellent viscosity stability and phase stability, and to be able to maintain stable properties for a long period of time among various synthesis methods.

[0049] Conventional alkyl ether carboxylate surfactants are generally known to be manufactured by the following two methods.

[0050] The first method is to produce a carboxylate by oxidizing ethylene oxide (EO) as shown in reaction scheme 1.

[0051] [Reaction Formula 1]

[0052] R(EO) n OH + {O} → R(EO) n-1 OCH2COOH

[0053] R(EO) n-1 OCH2COOH + NaOH → R(EO) n-1 OCH2COONa + H2O

[0054] The second method is to substitute the terminal OH of ethoxy alcohol with a carboxymethyl group using sodium monochloroacetate (ClCH2COONa) under alkaline conditions as shown in Reaction Scheme 2.

[0055] [Reaction Formula 2]

[0056] R(EO) n OH + ClCH2COONa → R(EO) n OCH2COONa + NaCl + H2

[0057] In this second method, when alkaline conditions are created using NaOH and the reaction proceeds, more than 5% of sodium chloride (NaCl) is generated and precipitated during the reaction. To remove this, water and an acidic solution (sulfuric acid or hydrochloric acid) are added to the product, alkyl ether carboxylate, to convert it into alkyl ether carboxylic acid, and then phase-separate it into a water layer containing sodium chloride and an alkyl ether carboxylic acid layer, and then the water layer is removed.

[0058] The conventional method of reaction scheme 2 produces an acidic alkyl ether carboxylic acid containing about 10% moisture due to the inherent water-containing properties of the surfactant. When a neutralizing agent is added to neutralize this again to produce an alkyl ether carboxylate, gelation occurs, making stirring itself impossible. Furthermore, even if a concentrated alkyl ether carboxylate is produced using mechanical force, it is difficult to produce a concentrated surfactant having a solids content of 60% surfactant active ingredient.

[0059] Due to these limitations, the structures that can be commercialized by Scheme 2 are limited to alkyl ether carboxylic acid forms with 80 to 90% surfactant content, alkyl ether carboxylates containing a large amount of water and having a solid content of about 24% (Comparative Example 1), and rarely paste-type alkyl ether carboxylates with a solid content of about 60% (Comparative Example 2).

[0060] Thus, the reason why there are two types of alkyl ether carboxylate surfactants, 24% and 60%, is that when the alkyl ether carboxylate surfactant exceeds 24%, it changes to a liquid crystal state in an aqueous solution, rapidly solidifies, and becomes impossible to stir. It only temporarily recovers fluidity at around 60%, and then gels again when it exceeds that amount.

[0061] In the present invention, based on the conditions of Reaction Scheme 2, alkyl ether carboxylate was prepared using monochloroacetic acid and sodium chloride, and then the water content was distilled under reduced pressure to within 3%, and then an inorganic salt was precipitated at 60 to 75°C. The amount of the inorganic salt (sodium chloride) produced at this time was 5 to 8 wt% based on 100 wt% of the surfactant active ingredient. Thereafter, the temperature was maintained and the pore size of the filter was adjusted to filter so that only a portion (0.5 to 3.5 wt%) of the inorganic salt (sodium chloride when NaOH was used) remained. Thereafter, water of approximately 15 to 25% of the total content was added to prepare a fluid alkyl ether carboxylate composition having a surfactant content of 75 to 85%. In particular, the remaining sodium chloride reduces the electric double layer of the negatively charged carboxyl group, inducing the formation of a lamellar structure, thereby obtaining a concentrated surfactant composition having fluidity. However, when the concentration of inorganic salt (sodium chloride) exceeds 2.8 wt% based on 80 wt% of surfactant, precipitation occurs and the properties become unstable. Therefore, it was confirmed that the concentration of inorganic salt (sodium chloride) is appropriate at 0.4 to 2.8 wt%.

[0062] Meanwhile, after producing alkyl ether carboxylate using sodium monochloroacetate as in Reaction Scheme 2, by adding hydrochloric acid or sulfuric acid to change to acidic conditions and removing the produced inorganic salt by filtering, an acidic alkyl ether carboxylic acid can be produced. This method can produce an alkyl ether carboxylic acid with excellent fluidity and a purity of 98% or more, close to 100%, with almost no moisture. In this case, it is desirable to remove as much sodium chloride as possible.

[0063] In the present invention, a method for removing sodium chloride may include a vacuum filter, a rotary vacuum drum filter, a Nutsche filter, a horizontal pressure leaf filter, a vertical pressure leaf filter, a centrifuge filter, a filter press, a screw press, etc., and is not limited to the listed equipment. However, in order to control the inorganic salts such as sodium chloride to a level of 0.5 to 3.5 wt%, it is preferable to set the pore size of the filter to 20 to 400 mesh (0.0015 to 0.033 inch).

[0064]

[0065] Laundry detergent composition

[0066] In another aspect, the present invention provides a laundry detergent composition comprising the concentrated surfactant composition.

[0067] The above laundry detergent composition may be in the form of a capsule-type detergent, a liquid detergent, or a concentrated gel-type detergent that maintains fluidity, and the concentrated surfactant composition of the present invention can provide properties that meet the technical requirements of each detergent formulation.

[0068] More specifically, the concentrated surfactant composition has a high solids content and excellent viscosity stability, making it easy to apply to gel-type formulations that maintain fluidity, and has low foaming and excellent rinsability, making it suitable for capsule-type or liquid-type detergents. In addition, the surfactant composition of the present invention has excellent cleaning power (stain removal power) and long-term storage stability at both high and low temperatures, so that it can exhibit excellent washing effects regardless of the type of washing machine or washing conditions. In addition, the concentrated surfactant composition of the present invention is transparent and has phase stability, and can improve work efficiency in the manufacturing and filling processes by optimizing the viscosity through the control of the inorganic salt.

[0069] The description of the above concentrated surfactant composition can be applied without limitation as a composition included in the present laundry detergent composition, and is interpreted to include all of the various compositions described in the claims and examples / experimental examples.

[0070] The above laundry detergent composition, by including the concentrated surfactant composition of the present invention, exhibits superior stain removal properties while suppressing foaming. Therefore, when applied to drum washing machines or high-speed rotation washing machines, it avoids sensor malfunctions and rinse residue issues due to excessive foaming. Furthermore, even with small loads of laundry, it provides sufficient cleaning effectiveness and rapid rinsing, thereby offering practical consumer benefits such as water savings and reduced time.

[0071] Furthermore, the concentrated surfactant composition of the present invention maintains stable fluidity and phase stability in a liquid state despite its solids content being controlled at 75 to 95 wt%, thereby maintaining product quality without separation or discoloration during long-term storage. This contributes to ensuring reliable product quality during distribution and consumer use.

[0072] Meanwhile, the concentrated surfactant composition of the present invention can be widely applied not only to laundry detergents for clothes but also to various other uses as follows. For example, it can be applied to personal care products that require low irritation and cleaning power, such as body wash, cleansing foam, and facial wash. In addition, it can be applied to pet shampoo or cleansing products because it has little foam, is easy to rinse, and has little concern about residue, making it suitable for sensitive animal skin. In addition, it can be used to clean work clothes, machine parts, etc., and can be applied to industrial detergents because it maintains its properties and cleaning power even in environments that require high-temperature stability.

[0073] As such, the concentrated surfactant composition of the present invention is evaluated as an excellent functional composition that satisfies the performance requirements required in various cleaning fields and provides both flexibility in formulation and the economic advantage of a highly concentrated composition.

[0074]

[0075] Method for preparing a concentrated surfactant composition

[0076] In another aspect, the present invention provides a method for preparing the concentrated surfactant composition.

[0077] The method for preparing the above-mentioned concentrated surfactant composition comprises the steps of (a) synthesizing an anionic surfactant represented by chemical formula 1 by carboxylating an alcohol ethoxylate having 8 to 18 carbon atoms (having an ethylene oxide addition mole number of 12 to 20);

[0078] (b) a step of removing some of the inorganic salts in the surfactant synthesized in step (a) through a filter to adjust the content of the inorganic salts to 3.5 wt% or less; and (c) a step of adjusting the total solid content to 75 to 95 wt% by adding purified water.

[0079] The above step (a) includes a step of synthesizing an alkyl ether carboxylate by reacting a carboxylating agent and a basic neutralizing agent to induce a carboxylation reaction, wherein the carboxylation reaction is a reaction that introduces a carboxyl group (-COOH) to a terminal hydroxyl group (OH) of an alcohol ethoxylate to form an anionic surfactant structure, and by using a carboxylating agent and a basic neutralizing agent together, a neutralized form of an ether carboxylate can be produced. This synthesis is carried out at a temperature of about 60 to 80°C and under stirring conditions, and inorganic salts such as sodium chloride generated during the reaction are simultaneously formed.

[0080] Monochloroacetic acid, sodium monochloroacetate, or bromoacetic acid can be used as the above-mentioned carboxylating agent. Sodium oxide, potassium hydroxide, ammonia water, or ethanolamines can be used as the above-mentioned basic neutralizing agent, and the ethanolamines can be monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), etc.

[0081] In the above step (b), it is important to appropriately remove inorganic salts formed excessively among the reaction products, leaving only a portion behind, as this can cause problems such as reduced transparency, phase instability, and gelation. In the present invention, inorganic salts are efficiently filtered using a filter with a mesh size of 20 to 400, and the inorganic salt content is adjusted to 0.5 to 3.5 wt% based on 100% of the surfactant active ingredient, thereby ensuring viscosity stability and long-term storage stability of the product.

[0082] In the above step (c), it is important to manufacture the product in a liquid form that maintains fluidity while controlling the solids content to 75-95 wt%. The amount of purified water added at this time is controlled to 5-25 wt% of the total weight. If the solids concentration is excessively low, economic feasibility is reduced, and conversely, if it is too high, viscosity rapidly increases due to the formation of a liquid crystal structure and gelation. Therefore, the moisture content is precisely controlled within the optimal range obtained experimentally.

[0083] Concentrated surfactant compositions manufactured using this method exhibit excellent fluidity despite their high solids content and can maintain a stable, transparent liquid state for long periods without phase separation. This technological advantage not only enhances storage and distribution stability as a high-concentration raw material, but also increases its potential for direct application in a variety of products, including laundry detergents, personal care products, pet shampoos, and cleansing products.

[0084]

[0085] Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention may be implemented in various different forms and is not limited to the examples described below.

[0086]

[0087] Experimental Example 1. Evaluation of foaming power according to the number of EO moles added to alkyl ether carboxylate (C12~14)

[0088] Alkyl ether carboxylates are representative anionic surfactants. Their excellent foam-generating and long-lasting properties make them widely used as foam-enhancing surfactants in personal care products such as shampoos and body cleansers. However, in laundry detergents, excessive foaming can interfere with the mechanical cleaning action and reduce rinsing efficiency, requiring low foaming and rapid removal. For these reasons, alkyl ether carboxylates have had limited use as laundry surfactants.

[0089] In the present invention, the foaming power of alkyl ether carboxylates having alkyl groups of C12 to C14 was evaluated according to the molar number of ethylene oxide (EO) added. Through this, the foaming characteristics according to the amount of EO added were analyzed and a low-foaming structure suitable for laundry detergents was identified.

[0090] Ethylene oxide (EO) was added to fatty alcohols having alkyl groups of C12 to C14 in an average amount of 3 to 18 mol at 3 mol intervals, and then alkyl ether carboxylates were synthesized through a carboxylation reaction. Each of the synthesized surfactant samples was dissolved in distilled water to 0.5 wt% to prepare a test detergent with a concentration of 0.5%, and these were used to evaluate the foaming ability.

[0091] The evaluation was conducted by placing a test detergent solution in a measuring cylinder, rotating it for 3 minutes using a rotary device, and measuring the height of the generated foam using the measuring cylinder scale.

[0092] Figure 1 shows the foaming power according to the mole number of EO added for alkyl ether carboxylates having C12~14 alkyl groups. The test results showed a tendency for the amount of foaming to decrease significantly when EO was added in amounts of 12 moles or more. Through this, it was confirmed that the condition of 12 moles or more of EO exhibited low-foaming characteristics and had the effect of quickly removing residual foam even during the washing machine rinsing process.

[0093]

[0094] Experimental Example 2. Evaluation of the contamination removal ability of alkyl ether carboxylate (C12~14) according to the number of EO moles added.

[0095] In this experiment, ethylene oxide (EO) was added to fatty alcohols having alkyl groups of C12 to C14 in 3-mol intervals from an average of 3 to 18 mol, and a carboxylating agent was reacted to synthesize alkyl ether carboxylates. Each of the synthesized surfactant samples was dissolved in distilled water to a concentration of 0.5 wt% to prepare a 0.5% concentration test detergent, and the contamination removal power (%) in a washing machine was evaluated.

[0096] The contamination removal power (%) was evaluated by loading a standardized contamination sheet with 1.5 kg of general laundry into a drum washing machine, washing was performed, and the contamination removal rate was calculated by comparing the reflectivity before and after washing.

[0097] The contamination sheets used were as follows, with 5 sheets of each type used:

[0098] - EMPA116 and EMPA117: Protein contamination

[0099] - W-10D and W-20D: Sebum contamination cloth

[0100] - JIS E-124: Japanese contamination cloth

[0101] The contaminated cloth was washed with the cloth evenly attached to the flat surface of the laundry. After washing, the cloth was dried and evenly spread out, and the change in reflectance was measured using a colorimeter.

[0102] Figure 2 shows the evaluation of the contamination removal ability according to the molar number of EO addition for alkyl ether carboxylate having a C12~14 alkyl group. As a result of the test, the optimal contamination removal ability was shown at the molar number of ethylene oxide (EO) addition of 12~18 mol, and when the molar number of addition exceeded 20 mol, the low-temperature stability was rapidly reduced, making it difficult to maintain a fluid liquid state at room temperature.

[0103]

[0104] Experimental Example 3. Preparation of surfactant compositions and evaluation of viscosity changes according to solid content concentration.

[0105] After installing a vacuum Nutsche Filter at the bottom of a 2 L reactor capable of heating and depressurizing, 886.84 g (1.0 eq) of alcohol ethoxylate (15 EO, molecular weight 846.17 g / mol) was added and heated while stirring. When the internal temperature reached 60°C, 89.04 g (0.9 eq) of monochloroacetic acid (molecular weight 94.5 g / mol) was added, then the stirring speed was reduced and 75.39 g (1.8 eq) of NaOH (molecular weight 40 g / mol) was added. In this state, the reaction was completed by stirring for 2 hours under conditions of 75°C and reduced pressure.

[0106] After the reaction was completed, the pressure was released, and the drain valve was opened while maintaining stirring, and the reactants were filtered through a Nutsche filter equipped with a 40 mesh screen. Some of the sodium chloride (NaCl) produced during this process was removed through filtration, and some remained in the final product, the alkyl ether carboxylate. At this time, the sodium chloride was adjusted so that it remained at a level of 2.0 wt% based on the alkyl ether carboxylate active ingredient.

[0107] The obtained alkyl ether carboxylate was stirred at 50-60°C, and purified water was added and mixed. The viscosity of each composition prepared according to the purified water content is as shown in Table 1.

[0108] According to Table 1, when the solid content was 20% or less, the viscosity was very low and the fluidity was excellent, but when the solid content increased to 30% or more, the orientation of the surfactant was converted to a liquid crystal state, the viscosity increased rapidly, and at some concentrations, gelation or phase separation occurred to the extent that viscosity measurement was impossible.

[0109] The effect of lamellar phase formation on viscosity was analyzed while continuously increasing the surfactant concentration. As a result, it was confirmed that viscosity decreased when the solids concentration reached around 80%.

[0110] Solids (%), Purified Water (%), Viscosity (cPs), 1000, Not measurable / Phase separation, 90, 10, Not measurable, 80, 20, 18, 20, 70, 30, Not measurable, 60, 40, 50, 50, 40, 60, 30, 70, 20, 80, 50, 10, 90, 30

[0111] To analyze this viscosity change range more precisely, surfactant compositions were prepared in the solids range of 75-85% and the viscosity changes were measured. The measurement results are shown in Table 2. According to Table 2, in the narrow concentration range of 76-83% solids, the surfactant was oriented in a lamellar structure and the viscosity showed a nonlinear decreasing trend. In particular, the lowest point (viscosity minimum value) appeared around 80%, and as the concentration increased thereafter, a viscosity increase and phase separation trend were observed again.

[0112] Solids (wt%)Water (wt%)Viscosity (cPs)8515Not measurable / Phase separation8416Not measurable / Phase separation831712,88082187,35081193,61080201,82079211,88078222,82077235,90076249,5427525Not measurable

[0113] As a result of confirming the viscosity change according to the solid content concentration of the surfactant composition according to the present invention, when the solid content is 20% or less, the viscosity is very low and the fluidity is excellent, and when the solid content is 30% or more, the viscosity increases rapidly, and at some concentrations, gelation or phase separation occurred, making it difficult to measure the viscosity. However, when the solid content is in the range of about 76-83%, a section was confirmed in which the viscosity decreased again due to the formation of a lamellar structure, proving that it is possible to prepare a highly concentrated composition with a solid content concentration of 75% or more even with an alkyl ether carboxylate surfactant in the form of a neutralized salt.

[0114]

[0115] Experimental Example 4. Comparison of inorganic salt content, viscosity, and phase stability according to filtering and composition conditions.

[0116] In this experimental example, the effects of the filtering process and composition conditions on the inorganic salt (residual sodium chloride) content, viscosity, and phase stability of the surfactant compositions manufactured were evaluated. Examples 1-5 were manufactured using ethoxylates in which 15 mol or 12 mol of ethylene oxide (EO) was added to lauryl alcohol, and surfactant compositions with various solid concentrations were manufactured by varying the filter size and the amount of purified water added. Comparative Examples 1-5 attempted to manufacture compositions with various concentrations without filtering, or to manufacture high-concentration compositions through oxidation or neutralization processes.

[0117]

[0118] Example 1. Preparation of 80% lauryl ether carboxylate (EO 15 mol) composition

[0119] After installing a vacuum Nutsche Filter at the bottom of a 2 L reactor capable of heating and depressurizing, 886.84 g (1.0 eq) of alcohol ethoxylate (EO 15 mol, molecular weight 846.17 g / mol) was added to the reactor and heated while stirring. When the internal temperature reached 60°C, 89.04 g (0.9 eq) of monochloroacetic acid (molecular weight 94.5 g / mol) was added, and then 75.39 g (1.8 eq) of NaOH (molecular weight 40 g / mol) was added while reducing the stirring speed. The reaction was completed by stirring at 75°C under reduced pressure for 2 hours.

[0120] After the reaction was completed, the pressure was released, the drain valve was opened while maintaining stirring, and the reactants were filtered through a Nutsche filter equipped with a 40-mesh mesh. Some of the sodium chloride (NaCl) produced during this process was removed by filtration, and some remained in the final product.

[0121] The obtained alkyl ether carboxylate was 982.5 g, and this was stirred while maintaining the temperature at 50 to 60°C, and 245.5 g of purified water was sequentially added and uniformly mixed to prepare a surfactant composition with 80% solids.

[0122]

[0123] Example 2. Preparation of 83% lauryl ether carboxylate (EO 15 mol) composition

[0124] The reaction was carried out in the same manner as in Example 1, and 201 g of purified water was added to 902.5 g of the obtained alkyl ether carboxylate and mixed uniformly to prepare a composition with a concentration of 83%.

[0125]

[0126] Example 3. Preparation of a 76% composition of lauryl ether carboxylate (EO 15 mol)

[0127] The reaction was carried out in the same manner as in Example 1, and 310 g of purified water was added to 902.5 g of the obtained alkyl ether carboxylate and mixed uniformly to prepare a composition with a concentration of 76%.

[0128]

[0129] Example 4. Preparation of 80% lauryl ether carboxylate (EO 12 mol) composition

[0130] In the same manner as in Example 1, 754.8 g (1.0 eq) of alcohol ethoxylate (molecular weight 714.2 g / mol) of EO 12 mol was added to the reactor and heated while stirring. When the internal temperature reached 60°C, 89.04 g (0.9 eq) of monochloroacetic acid was added, and then NaOH was added under the same conditions to complete the reaction. After the reaction, the mixture was filtered, and 229.8 g of purified water was added to 919.2 g of the obtained alkyl ether carboxylate and mixed uniformly to prepare a composition with a concentration of 80%.

[0131]

[0132] Example 5. Preparation of 80% lauryl ether carboxylate (EO 15 mol) composition (100 mesh filter applied)

[0133] A composition was prepared under the same reaction conditions as Example 1, but a 100 mesh filter was used instead of a 40 mesh filter in the filtration step. 236 g of purified water was added to 953 g of the alkyl ether carboxylate obtained after the reaction and mixed evenly to prepare a composition with a concentration of 80%.

[0134]

[0135] Comparative Example 1. Preparation of a 24% composition containing low-concentration lauryl ether carboxylate (EO 15 mol).

[0136] 698 g of lauryl alcohol ethoxylate (EO 15 mol) was added to a reactor and heated to 70-75°C under a nitrogen atmosphere. Then, 74 g of a mixture of sodium monochloroacetate and sodium borohydride was added, followed by dropwise addition of 43 g of a 50% aqueous sodium hydroxide (NaOH) solution. Subsequently, the pressure was reduced to 30 Torr to remove moisture, and the reaction was carried out for 5 hours.

[0137] 20 g of purified water was added, stirred, and aged for 1 hour. Then, 35% hydrochloric acid was added to reach pH 3, and water was added until the precipitated sodium chloride (NaCl) was completely dissolved. The resulting solution was then stirred at 90°C for 1 hour and left for another hour to separate the oil layer. The separated oil layer is lauryl ether carboxylic acid, and in order to convert it to lauryl ether carboxylate, 76 wt% of the obtained product was added with purified water and NaOH beads, and the pH was neutralized to around 7 to prepare a lauryl ether carboxylate composition with a concentration of 24%.

[0138]

[0139] Comparative Example 2. Preparation of a 60% composition containing medium-concentration lauryl ether carboxylate (EO 15 mol).

[0140] The oil layer lauryl ether carboxylic acid was obtained in the same manner as in Comparative Example 1, and in order to convert the obtained product into lauryl ether carboxylate, 40% by weight of purified water and NaOH beads were added based on the obtained product, and neutralized to about pH 7 to prepare a 60% concentration lauryl ether carboxylate composition. At this time, it was impossible to manufacture with a general stirrer due to a rapid increase in viscosity, and neutralization was attempted by raising the temperature to a high temperature of 80 to 90°C and using a scraper-type neutralization reactor separately in an anchor-type stirrer, and as a result, a 60% lauryl ether carboxylate paste with extremely low fluidity in the gel type could be obtained.

[0141]

[0142] Comparative Example 3. Preparation of a 70% composition containing high concentration lauryl ether carboxylate (EO 15 mol).

[0143] In order to obtain lauryl ether carboxylic acid of the oil layer obtained in the same manner as in Comparative Example 1, and to convert the obtained product into lauryl ether carboxylate, 30% by weight of purified water and NaOH beads were added relative to the obtained product and neutralized to about pH 7 to prepare a lauryl ether carboxylate composition having a concentration of 70%. However, despite using a scraper-type neutralization reactor separately in an anchor-type stirrer, it was impossible to manufacture due to a rapid increase in viscosity.

[0144]

[0145] Comparative Example 4. Preparation of 80% high-concentration lauryl ether carboxylate (EO 15 mol) composition

[0146] In order to obtain lauryl ether carboxylic acid of the oil layer obtained in the same manner as in Comparative Example 1, and to convert the obtained product into lauryl ether carboxylate, 20% by weight of purified water and NaOH beads were added relative to the obtained product to neutralize the product to a pH of around 7, thereby producing 80% lauryl ether carboxylate. However, despite using a scraper-type neutralization reactor separately in an anchor-type stirrer, production was impossible due to a rapid increase in viscosity.

[0147]

[0148] Comparative Example 5. Preparation of 80% lauryl ether carboxylate (EO 15 mol) composition through oxidation reaction.

[0149] In a 1,000 mL multi-neck flask, 250 g of lauryl alcohol ethoxylate (EO 15 mol) was added, and 15 g of a metal catalyst doped with rhenium was added under a nitrogen atmosphere, followed by heating to 180-185°C and stirring. 47 g of a 40% sodium hydroxide (NaOH) aqueous solution was added dropwise over 8 hours. During the reaction, a vacuum condition was created to remove water. Once the addition of sodium hydroxide was completed, the mixture was stirred for an additional 30 minutes and the reaction was terminated. The reactant was filtered through a Buchner funnel, and 20 wt% of purified water was added to prepare lauryl ether carboxylate (EO 15 mol), but gelation occurred, making it impossible to prepare a composition with a solid content of 80%.

[0150]

[0151] [Experimental Results]

[0152] The results of Experimental Example 4 are shown in Table 3, and the characteristics of the surfactant composition were evaluated according to changes in solid content, filtering conditions, and EO mole number.

[0153] As a result, in Examples 1 to 5, where the solid content was approximately 76 to 83% (moisture content 17.2 to 23.7%), the viscosity was maintained in the range of 1,270 to 11,950 cPs, and phase stability was maintained at room temperature for 30 days. These compositions were able to secure a uniform and fluid state even at high solid content concentrations.

[0154] In particular, Example 5 was able to control the residual sodium chloride content to a low level of 0.88% by using a 100 mesh filter, and Example 4 (12 moles) with a different EO mole number also showed a viscosity of 1,270 cPs and phase stability, confirming that the manufacturing method of the present invention is effective when the EO mole number is 12 to 20 moles.

[0155] On the other hand, Comparative Examples 2 to 5 were either impossible to manufacture or exhibited an immobile state due to a rapid increase in viscosity or gelation under conditions of high solids content, limiting their industrial application. Comparative Example 1 had a high moisture content of 75.8%, resulting in low viscosity and maintained phase stability, but its application as a concentrated surfactant with a high solids content was limited.

[0156] Accordingly, the present invention has been proven to be effective in the practical production of a high-concentration surfactant composition, as it can achieve stable viscosity and phase stability while securing a solid content of 75% or more.

[0157] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Moisture content (%) (karlfischer) 19.7 17.2 23.7 20.1 20.2 75.8 40.0 30.0 20.0 20.0 Sodium chloride content (%) 1.3 8 1.4 21.3 31.2 30.8 80.1 10.2 8 Not manufacturable Not manufacturable Not manufacturable Viscosity (cPs, 25℃) 1,980 11,950 9,2 201,2 701,750 17 Not measurable Stability (25℃, 30 days) Stable Stable Stable Stable Stable Non-flowability

Claims

1. A concentrated surfactant composition comprising an anionic surfactant represented by chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, m is an integer from 7 to 17, n is an integer from 12 to 20, and X is H, Na, K, ammonium, or amine.

2. A concentrated surfactant composition according to claim 1, wherein n is an integer from 12 to 18, and X is H, Na, K, or an amine.

3. A concentrated surfactant composition according to claim 1, wherein the composition contains 75 to 95 wt% of the solid content of the surfactant and 5 to 25 wt% of the moisture.

4. A concentrated surfactant composition in the third paragraph, wherein the solid content contains 0.5 to 3.5 wt% of an inorganic salt based on 100 wt% of the surfactant active ingredient.

5. A concentrated surfactant composition in accordance with claim 4, wherein the content of the inorganic salt is controlled by filtration using a filter having a size of 20 to 400 meshes.

6. In the first paragraph, the surfactant of the chemical formula 1 has a low-foaming property in which the amount of foam generated is significantly reduced when the number of added moles of ethylene oxide is 12 or more, thereby improving the rinsability after washing.

7. A concentrated surfactant composition in claim 6, wherein the surfactant of the chemical formula 1 maintains excellent contamination removal ability at an added mole number of ethylene oxide of 12 to 20.

8. A concentrated surfactant composition according to claim 1, wherein the composition maintains phase stability and viscosity stability at room temperature for 30 days or more.

9. A laundry detergent composition comprising a concentrated surfactant composition according to any one of claims 1 to 8.

10. A laundry detergent composition according to claim 9, wherein the laundry detergent composition is in the form of a capsule-type detergent, a liquid detergent, or a concentrated gel-type detergent that maintains fluidity.

11. A method for producing a concentrated surfactant composition according to paragraph 1, (a) A step of synthesizing an anionic surfactant represented by chemical formula 1 by carboxylating an alcohol ethoxylate having 8 to 18 carbon atoms (having an ethylene oxide addition mole number of 12 to 20); (b) a step of removing some of the inorganic salts in the surfactant synthesized in step (a) through a filter to adjust the content of the inorganic salts to 3.5 wt% or less; and (c) A method for producing a concentrated surfactant composition, characterized by comprising a step of adjusting the total solid content to 75 to 95 wt% by adding purified water.

12. In the 11th paragraph, the step (b) is a method for producing a concentrated surfactant composition, wherein the content of inorganic salt is adjusted to 0.5 to 3.5 wt% based on 100 wt% of surfactant active ingredient using a filter having a mesh size of 20 to 400.

13. In the 11th paragraph, the step (a) includes a step of synthesizing an alkyl ether carboxylate by reacting a carboxylating agent and a basic neutralizing agent to induce a carboxylation reaction, A method for producing a concentrated surfactant composition, wherein in the step (c) above, the moisture content is controlled to 5 to 25 wt%.

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