WO2024138450A1

WO2024138450A1 - Surfactants with improved emulsification performance

Info

Publication number: WO2024138450A1
Application number: PCT/CN2022/143000
Authority: WO
Inventors: Hua Ren; Yang Zhang; Cheng Shen
Original assignee: Dow Global Technologies Llc
Priority date: 2022-12-28
Filing date: 2022-12-28
Publication date: 2024-07-04

Abstract

The present disclosure is concerned with a nonionic surfactant having a nonionic block copolymer structure of Formula I:R-[A]x– [B]y Formula I where R is a C8 to C30 alkyl; x is 8 to 20; y is 2 to 20; the [A]x block is formed from propylene oxide; the [B]y block is formed from ethylene oxide; and the nonionic surfactant has a cloud point higher than 15 ℃.

Description

Surfactants With Improved Emulsification Performance

Field of Disclosure

Embodiments of the present disclosure are directed towards surfactants and specifically surfactants with improved emulsification performance.

Background

Emulsification performance of surfactants is important in many areas, such as cleaning, detergency, and soil removal. Emulsification performance towards vegetable or animal oils is very important for detergency and degreasing performance. To improve emulsification performance, surfactants with varied structures have been developed and commercialized, but there remains a need in the art for surfactants that can provide improvements in emulsification performance, especially when it comes to dealing with vegetable and/or animal oils. One approach to improve cleaning performance has been to use alkaline compounds in detergent formulations. These compounds, however, can cause skin irritation for applications like hand dish cleaning etc. As a result, improving the emulsification performance of surfactants turns out to be a better option than the use of alkaline compounds. Thus, there is a need in the art for an extended nonionic surfactant that can provide strong emulsification performance, especially towards vegetable or animal oils.

One area of interest in improving emulsification performance has been in what are referred to as “extended surfactants. ” Compared with conventional surfactants, extended surfactants include an intermediate polarity spacer, such as a block formed with propylene oxide (PPO) or PPO-polyethylene-oxide (PEO) , which is inserted between the hydrophilic head and hydrophobic tail. Research has indicated that the PO groups with weak lipophilic feature may provide a smooth polarity-transition zone between the hydrophobic tail and hydrophilic head, which can provide better emulsification than traditional surfactant without PO segments. But what structure of extended surfactant can provide best emulsification performance remains unknown and so a need in the art remains.

Summary

The present disclosure relates to the structure performance relationship in terms of the emulsification performance of a nonionic surfactant towards vegetable and animal oils, where the nonionic surfactant structure identified is shown to have improved emulsification performance relative to other surfactants. Such an improvement in nonionic surfactants can be beneficial in the areas of emulsification performance in applications such as cleaning, detergency and soil removal.

To that end, the present disclosure provides for a nonionic surfactant that includes a nonionic block copolymer structure of Formula I:

R- [A] _x– [B] _y Formula I

where R is a C8 to C30 alkyl; x is 8 to 20; y is 2 to 20; the [A] _x block is formed from propylene oxide; the [B] _y block is formed from ethylene oxide; and the nonionic surfactant has a cloud point higher than 15 ℃. For the various embodiments, R can be a C12 to C18 alkyl. For the various embodiments, R can be a linear alkyl. For the various embodiments, x can be 8 to 10. For the various embodiments, y can be 4 to 10. For the various embodiments, R can be C12-C14, x can be 8 and y can be 7. For the various embodiments, R can be C12-C14, x can be 8 and y can be 9. For the various embodiments, R can be 2-ethyl hexyl, x can be 8 and y can be 4. For the various embodiments, R can be C8-C14, x can be 8 and y can be 4. For the various embodiments, R can be C16-C18, x can be 10 and y can be 10.

Brief Description of Drawings

Figs. 1A and 1B provide emulsification performance of formulations comprising EX 1, ethylene glycol phenyl ether solvent and MIPA/DIPA amine according to the present disclosure.

Figs. 2A and 2B provide emulsification performance of formulations comprising CE I, ethylene glycol phenyl ether solvent and MIPA/DIPA amine according to the present disclosure.

Detailed Description

The present disclosure relates to the emulsification performance of a nonionic surfactant towards mineral oil, vegetable and animal oils (referred to hereinafter as “oils” ) , where this nonionic surfactant structure has improved emulsification performance relative to other surfactants. Such an improvement in nonionic surfactants can be beneficial in the areas of emulsification performance in applications such as cleaning, detergency and soil removal. In particular, the nonionic surfactant of the present disclosure can be used in emulsions for the removal of oils from textiles materials such as, but not limited to, fabric, yarn, or other woven material comprising a network of natural or artificial fibers. For example, the nonionic surfactant of the present disclosure may be used in various cleaning processes, such as scouring or laundering (i.e., cleaning) , for the treatment or pre-treatment of the textile material fabric. In order to obtain effective cleaning performance (i.e., effective removal of oils) , the nonionic surfactant composition should have effective emulsification performance, among other properties. Such properties allow the surfactant to penetrate the textile material and surround the oil for removal.

Unless otherwise indicated, numeric ranges, for instance as in “from 2 to 10, ” are real numbers and are inclusive of the numbers defining the range (e.g., 2 and 10) .

Unless otherwise indicated, ratios, percentages, parts, and the like are by weight.

As noted above, the disclosure provides for a nonionic surfactant that includes a nonionic block copolymer structure of Formula I:

R- [A] _x– [B] _y Formula I

where R is a C8 to C30 alkyl; x is 8 to 20; y is 2 to 20; the [A] _x block is formed from propylene oxide (PO) ; the [B] _y block is formed from ethylene oxide (EO) ; and the nonionic surfactant has a cloud point higher than 15 ℃. For the various embodiments, preferably the cloud point of Formula I is higher than 20℃. The propylene oxide used in forming the [A] _x block can be 1, 2-propylene oxide.

For the various embodiments, R can be linear or branched. For the various embodiments, R can be a linear alkyl. Preferably, R is an alkyl no shorter than C8. More preferably, R is an alkyl that is no shorter than C12. In additional embodiments, R can be a C12 to C18 alkyl. For the various embodiments, R can be a C12 to C14 alkyl. For the various embodiments, R can be a C16 to C18 alkyl. For the various embodiments, R can be 2-ethyl hexyl.

For the various embodiments, x is no less than 8. For the various embodiments, x can be 8 to 10. For the various embodiments, y is greater than 2. For the various embodiments, y can be 4 to 10. In more specific embodiments, R can be a C12 to C14 alkyl, x can be 8 and y can be 7. For the various embodiments, R can be C12 to C14, x can be 8 and y can be 9. For the various embodiments, R can be 2-ethyl hexyl, x can be 8 and y can be 4. For the various embodiments, R can be C8-C14, x can be 8 and y can be 4. For the various embodiments, R can be C16 to C18, x can be 10 and y can be 10.

The nonionic block copolymer structure of Formula I can be obtained in conventional manners by reacting an alcohol with alkylene oxides, such as ethylene oxide (EO) and propylene oxide (PO) , in the presence of a catalyst. Polymerization can be bulk polymerization or solution polymerization. Catalysts suitable for polymerization of alkylene oxide can be found in literature, for example F. E. Bailey, Jr., Joseph V. Koleske, “Alkylene Oxides and Their Polymers” Marcel Dekker, New York, 1991, p. 35, including anionic or basic catalysts, acid or cationic catalysts, and coordinate catalysts, for example, postassium hydroixde (KOH) , boron trifluoride, or double metal cyanide complex (DMC) catalysts such as zinc hexacyanocobaltate.

The alkylene oxides are typically fed into a reactor containing dried initiator and the catalyst at temperatures varying from 50 to 160 ℃. When the pressure in the reactor returns to approximately the same pressure before feeding the alkylene oxides, the polymerization is usually considered complete. The catalysts can be neutralized, removed by known means, for example filtration, adsorption, and ionic exchange, or left in the products depending on the products and applications.

The present disclosure further includes a surfactant composition that includes the nonionic surfactant of the present disclosure. For the various embodiments, the surfactant composition can include, but is not limited to, the nonionic surfactant of the present disclosure, water, one or more of an amine, and/or one or more of a solvent. For the various embodiments, the surfactant composition can include 5 to 30 weight percent (wt. %) of the nonionic surfactant of the present disclosure; 70 to 80 wt. %of water; 0 to 25 wt. %of one or more of the amine; and 0 to 25 wt. %of one or more of the solvent, where the wt. %is based on the total weight of the surfactant composition. Embodiments of the surfactant composition also include those in which water is not initially present, where the surfactant composition is subsequently mixed with the water to produce an aqueous solution having, for example a 0.1 to 10 wt. %solution of the surfactant composition.

For the various embodiments, the one or more of the amine can include, but are not limited to, alkanolamines, alkyl alkanolamines and combinations thereof. For example, the one or more of the amine can be selected from the group consisting of monisopropanolamine (MIPA) , diisopropanolamine (DIPA) , ethanolamine (MEA) , triethanolamine (TEA) , diethylethanolamine (DEEA) , dimethylethanolamine (DMEA) , methyl diethanolamine (MDEA) , n-methylethanolamine (NMEA) and combinations thereof.

For the various embodiments, the one or more of the solvent can include, but are not limited to, glycol ethers such as ethylene glycol phenyl ether, propylene glycol phenyl ether, diethylene glycol butyl ether, dipropylene glycol methyl ether, 1- (2-butoxy-1-methylethoxy) propan-2-ol, 1-methoxy-2-propyl acetate, [2- (2-methoxymethylethoxy) methylethoxy] propanol, ethylene glycol monobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monobutyl ether, ethylene glycol monohexyl ether and combinations thereof.

The surfactant composition can further include other optional additives. Examples of such additives include those that do not interfere with the emulsification performance of the nonionic surfactant of the present disclosure and/or the surfactant composition that includes the nonionic surfactant of the present disclosure. Examples of such additives include, but are not limited to, bases such as sodium hydroxide, oxidizing agents such as hydrogen peroxide and other surfactants such as ionic surfactants and non-ionic surfactants, alcohol ethoxysulphates, linear alkylbenzene sulfonate, alkyldiphenyloxide disulfonate, among others known in the art.

For the various embodiments, the surfactant composition of the present disclosure can be used in processes for cleaning and/or scouring of articles that are soiled with oils as provided herein. Such processes can take place at a temperature of 0 to 100 ℃ and a pressure of 0.5 to 1.5 kPa. For example, the surfactant composition of the present disclosure can be used for scouring textile materials by contacting the textile with a surfactant composition that includes the nonionic surfactant.

EXAMPLES

The examples below are provided to be illustrative only and are not intended to define or limit the embodiments in any way. In the Inventive Examples (EX) and Comparative Examples (CE) , various terms and designations for materials are used including, for instance, the following:

Table 1 -Materials

Table 2 –Example (EX) and Comparative Example (CE) Surfactants

a: cloud point measured in 10 wt. %aq. soln.

Synthesis Example 1: Synthesis of nonionic surfactant represented by the formula: L-C _12-14- (PO) ₈- (EO) ₇, where L-C _12-14 refers to a linear C _12-14 moiety. One mole of L-C _12-14 alcohol and aqueous solution of potassium hydroxide (45-50 wt. %) were charged into the reactor. The KOH content was added at around 0.17 wt. %based on the weight of final product. The mixture was heated to around 50-60 ℃ for 30 min. The moisture was controlled to an amount of less than 1000 ppm after vacuum stripping at about 80 ℃, the mixture was then kept at around 110-140 ℃. A first portion of PO in eight moles (corresponding to eight molar equivalents of L-C _12-14 alcohol) was then fed slowly into the reactor. When the pressure in the reactor returned to approximately same as the pressure before PO feeding, seven moles of EO (corresponding to 7 molar equivalents of L-C _12-14 alcohol) was fed into the reactor slowly and the reactor temperature was kept at 110-140 ℃. When the pressure in the reactor returned to approximately same as the pressure before EO feeding, the reaction was maintained at 110-140 ℃ for 2 more hours to ensure a full consumption of EO. After the N ₂ purge to remove residual oxide, the reactor was cooled down to around 60 ℃ at ambient pressure. Then, acetic acid was added into the reactor to neutralize the KOH catalyst. After cooling down to around 40 ℃, the desired product was obtained.

Synthesis Example 2: Synthesis of nonionic surfactant represented by the formula: L-C _12-14- (PO) ₈- (EO) ₉, where L-C _12-14-refer to a linear C _12-14-moiety

Synthesis Example 2 was conducted similar to synthesis example 1, but L-C _12-14 alcohol was used as a starting alcohol in step 1, and the amounts of PO and EO fed into the reactor were changed accordingly.

Synthesis Example 3: Synthesis of nonionic surfactant represented by the formula: 2-ethylhexyl- (PO) ₈- (EO) ₆.

Synthesis Example 3 was conducted similar to synthesis example 1, but 2-ethyl hexanol was used as a starting alcohol in step 1, and the amounts of PO and EO fed into the reactor were changed accordingly.

Synthesis Example 4: Synthesis of nonionic surfactant represented by the formula: L-C _8-14- (PO) ₈- (EO) ₄, where L-C _8-14-refer to a linear C _8-14-moiety

Synthesis Example 4 was conducted similar to synthesis example 1, but L-C _8-14 alcohol was used as a starting alcohol in step 1, and the amounts of PO and EO fed into the reactor were changed accordingly.

Synthesis Example 5: Synthesis of nonionic surfactant represented by the formula: L-C _16-18- (PO) ₁₀- (EO) ₁₀, where L-C _16-18-refer to a linear C _16-18-moiety

Synthesis Example 5 was conducted similar to synthesis example 1, but L-C _16-18 alcohol was used as a starting alcohol in step 1, and the amounts of PO and EO fed into the reactor were changed accordingly.

Synthesis Example 6: Synthesis of nonionic surfactant represented by the formula: L-C _12-14- (PO) ₁₂- (EO) ₆, where L-C _12-14-refer to a linear C _12-14-moiety

Synthesis Example 6 was conducted similar to synthesis example 1, but L-C _12-14 alcohol was used as a starting alcohol in step 1, and the amounts of PO and EO fed into the reactor were changed accordingly.

Formulation Emulsification Performance Evaluation

To test emulsification performance, a 400 μL surfactant solution (1 wt. %of surfactant in water) was dispensed into 1 mL vials, then 150 μL of liquid oil was added on the top of the solution. After capping, the vials were shaken by automated shaker in PICA II robot (an internal imaging robot with vial shaker) at intensity 7 for 60 seconds, then images of the samples were taken after shaking, the gray scale value of the aqueous part of the vial was measured using ImageJ [1. Rasband, W.S., ImageJ, U.S. National Institutes of Health, Bethesda, Maryland, USA, https: //imagej. nih. gov/ij/, 1997-2018. ] to quantify the emulsification performance of the formulation. The higher gray scale value (indicating the whiter appearance of the emulsion) , the better the emulsification performance. For the present tests, the liquid oil was a mixture of corn oil: peanut oil: sunflower seed oil in a 1: 1: 1 by wt. ratio, if not specified otherwise.

Soil Removal Procedure –Detergent Testing

Soil removal performance (detergent testing) of different surfactant solutions was also evaluated using polyester fabric with an olive oil stain. A Tergotometer (Model TRG 800i, Copley) was used for the soil removal test with the following process parameters: Dosage: 0.4 g/L; Temperature: 30 ℃; Stirring rotation speed: 120 rpm; Washing time: 20 minutes; Water: Water hardness 120 ppm; Swatches: The swatches used in this study are listed in table 1 (size 5 cm×5cm)

The color of dry swatches was measured by the spectrophotometer (Konica Minolta Spectrophotometer CM-3600A) before and after washing. Each piece was measured on the soiled side. The output of color measurement included L*, a*and b*. Detergency was calculated based on the following formula:

The standard polyester fabric with olive oil stain was used, the detailed information of the fabric with stain shown in Table 3.

Table 3. Detailed information about the polyester fabric with stain

Swatch Name	Code	Soils/Fabric	Supplier
POP	W‐30 B	Pigment, olive oil/polyester	WFK

Examples for demonstrating the emulsification performance of surfactant

Table 4. Emulsification performance comparison

EX 1-6 shown in Table 4 demonstrate better emulsification performance than comparative examples, where the higher gray scale value indicates better performance. From this data it is determined that nonionic surfactants having the nonionic block copolymer structure of Formula I as provided herein:

R- [A] x– [B] y Formula I

can provide better emulsification performance towards vegetable oils. For example, with the same hydrophobic tail, a more hydrophobic surfactant (lower cloud point) tends to give a better emulsification performance towards the vegetable oil mixture. However, there are some differences between triblock structure (R- [EO] z- [PO] x- [EO] y) and diblock counterpart of the present disclosure (R- [PO] x- [EO] y) . With similar hydrophobicity (similar cloud point) , the surfactants with diblock structure tend to provide better emulsification performance, e.g., EX 2 (C12-14-PO8-EO9) with cloud point = 40 ℃ (at 1 wt. %aq. soln. ) gives better performance than both CE D (C12-14-EO4-PO8-EO4, cloud point=34 ℃, at 1 wt. %aq. soln. ) and CE E (C12-14-EO4-PO8-EO6, cloud point=42 ℃, at 1 wt. %aq. soln. ) , which indicates that, the introduction of internal EO block may hurt the emulsification performance.

The comparison between CE I and EX 3 shows that, minor improvement is observed when only longer internal PO segment is introduced (the number of PO units in CE I is 5, and the PO number in EX 3 is 8) . This comparison indicates that, both a longer hydrophobic tail and a longer PO segment in the general structure are beneficial to provide good emulsification performance; furthermore, the PO segment being directly connected to the hydrophobic tail without extra EO units is beneficial. If extra internal EO units are present, even with longer hydrophobic tail like CE G (C16-18-EO4.42-PO13.74-EO5, with a cloud point of 28 ℃) , the surfactant tends to give lower emulsification performance.

The nonionic surfactants of the present disclosure are also further supported by the comparison with CE P and CE Q surfactants. As the CE P and CE Q surfactants have longer hydrophobic tails (linear C8-14 alcohol with an average carbon number around C10) than that of the CE I surfactant (2-ethyl hexanol) , when longer PO block being introduced, more significant emulsification performance improvement is observed if we compare the performance among CE Q, CE M and CE O. For example, the performance of CE O (12 PO units) is greater than CE M (8 PO units) which is greater than CE Q (3 PO units) , which is well aligned with the number of PO units.

The removal of vegetable oil on polyester also demonstrates the better performance of inventive surfactants with the structure of Formula I, as further demonstrated in Table 5, where the results in Table 5 also confirm the positive emulsification performance on soil removal, especially for polyester fabric.

As seen in Table 5, EX 1 and EX 2 give much better soil removal performance than CE I, CE P and CE Q.

Table 5. Vegetable oil removal performance (olive soil on polyester)

In order to further demonstrate the performance of the nonionic surfactants of the present disclosure, their performance in the above formulated systems was compared with the other surfactants, solvent and amine. A 1%aqueous solution comprising surfactant, solvent and amine was prepared according to the dosage in Table 6, the solution sample was thoroughly mixed to form homogeneous solution at room temperature (23 ℃) , then their emulsification performance was evaluated using the same procedure described in “Formulation Emulsification Performance Evaluation”

Table 6. Composition of Surfactant, Solvent and Amine

In Figs. 1A and 1B, the higher value (axis on the right side of the figures) indicates better performance, therefore the closer the data points are to the axis on the right side of the figures the better the emulsification.

In comparison, the performance of another extended nonionic surfactant CE I was also evaluated and is seen in Figs. 2A and 2B.

It can be clearly seen in both Figs. 1A-1B and 2A-2B that the formulation with the inventive surfactant can give good emulsification performance in the whole dosage range; while for the traditional extended nonionic surfactant as CE I, only the formulations with higher amine dosage can give good performance; as a result, the performance comparison here demonstrates the superior performance of the inventive extended nonionic surfactants with general structure 1.

Based on the results above, it can be concluded that, the nonionic surfactants meeting the below three structure characters: Longer hydrophobic tail (carbon number >= 8, more preferred >= 12) ; Longer propylene oxide (PO) unit (>= 8) and the PO unit being directly connected to the hydrophobic tail.

Claims

A nonionic surfactant, comprising:

a nonionic block copolymer structure of Formula I:

R- [A] _x– [B] _y Formula I

wherein R is a C8 to C30 alkyl; x is 8 to 20; y is 2 to 20; the [A] _x block is formed from propylene oxide; the [B] _y block is formed from ethylene oxide; and the nonionic surfactant has a cloud point higher than 15 ℃.
The nonionic surfactant of claim 1, wherein R is a C12 to C18 alkyl.
The nonionic surfactant of any one of claims 1-2, wherein R is a linear alkyl.
The nonionic surfactant of any one of claims 1-3, wherein x is 8 to 10.
The nonionic surfactant of any one of claims 1-4, wherein y is 4 to 10.
The nonionic surfactant of claim 1, wherein R is C12-C14, x is 8 and y is 7.
The nonionic surfactant of claim 1, wherein R is C12-C14, x is 8 and y is 9.
The nonionic surfactant of claim 1, wherein R is 2-ethyl hexyl, x is 8 and y is 4.
The nonionic surfactant of claim 1, wherein R is C8-C14, x is 8 and y is 4.
The nonionic surfactant of claim 1, wherein R is C16-C18, x is 10 and y is 10.