A polyglycerol-modified surfactant, its preparation method and application

Abstract

This invention relates to a polyglycerol-modified surfactant, its preparation method, and its application. The preparation method includes the following steps: mixing polyglycerol, a silane coupling agent, and a catalyst, and reacting at 22-40°C for 0.1-2 h to obtain the polyglycerol-modified surfactant; the mass ratio of polyglycerol to the silane coupling agent is 1:3-5; and the silane coupling agent has ≥3 alkoxy groups. The polyglycerol-modified surfactant of this invention has an HLB value between 10 and 20 and exhibits good stability at high temperatures due to its three-dimensional structure, thus demonstrating excellent emulsifying properties at high temperatures and applicable to high-temperature cleaning scenarios in metal processing, automotive manufacturing, and other fields.

Description

Technical Field

[0001] This invention relates to the field of surfactant technology, and more specifically, to a polyglycerol-modified surfactant, its preparation method, and its application. Background Technology

[0002] In metal processing, automobile manufacturing, and other fields, high-temperature cleaning of parts is often required, and cleaning agents are typically used repeatedly and for extended periods. These high-temperature cleaning scenarios necessitate the use of surfactants with high HLB values ​​(10-20), primarily anionic surfactants such as sulfonates and carboxylates. However, these anionic surfactants can corrode metal materials, easily causing corrosion to cleaning equipment, and may also pollute the environment.

[0003] Organosilicon surfactants are widely used in cosmetics and other fields due to their advantages of low or non-toxicity to humans, mild properties, excellent physicochemical properties, and high plasticity. Organosilicon surfactants are mainly obtained by introducing hydrophilic groups or hydrophilic segments (such as polyether segments) onto polysiloxane chains, as exemplified by the Chinese patent entitled "Organosilicon Surfactants and Their Preparation Methods and Applications." Existing organosilicon surfactants typically have HLB values ​​of 10-20, meeting the requirements for everyday cleaning applications. However, existing organosilicon surfactants are prone to decomposition at high temperatures, thus reducing their cleaning efficiency and making them unsuitable for high-temperature cleaning applications in metal processing, automotive manufacturing, and other fields. Summary of the Invention

[0004] The primary objective of this invention is to overcome the problem of poor high-temperature resistance of existing organosilicon surfactants and to provide a method for preparing a polyglycerol-modified surfactant. This polyglycerol-modified surfactant has an HLB value between 10 and 20 and exhibits good stability at high temperatures due to its structural characteristics, thus enabling it to exert excellent emulsifying effects at high temperatures and be applied in high-temperature cleaning scenarios in metal processing, automotive manufacturing, and other fields.

[0005] A further object of the present invention is to provide a polyglycerol-modified surfactant.

[0006] Another objective of this invention is to provide the use of a polyglycerol-modified surfactant in the preparation of emulsifiers, lubricants, or coatings.

[0007] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0008] A method for preparing a polyglycerol-modified surfactant includes the following steps:

[0009] Polyglycerol, silane coupling agent and catalyst are mixed and reacted at a temperature of 22~40℃ for 0.1~2 h to obtain the polyglycerol modified surfactant.

[0010] The mass ratio of the polyglycerol to the silane coupling agent is 1:3~5;

[0011] The silane coupling agent has ≥3 alkoxy groups.

[0012] The inventors of this invention discovered through research that when polyglycerol and silane coupling agents react at certain temperatures and times, on the one hand, hydrolytic condensation reactions can occur between the silane coupling agents to form polysiloxane segments; on the other hand, utilizing the polyhydroxy structure of polyglycerol and the multiple alkoxy groups of the silane coupling agent, a condensation reaction can occur to form a polyglycerol-modified surfactant with a three-dimensional structure. The HLB of this polyglycerol-modified surfactant is between 10 and 20, and due to the characteristics of its three-dimensional structure, it has good stability at high temperatures, thus enabling it to exert its good emulsifying effect at high temperatures and be applied to high-temperature cleaning scenarios in fields such as metal processing and automobile manufacturing.

[0013] If the silane coupling agent used has two alkoxy groups or other hydrophilic modifiers (such as polyethylene glycol) are used, a linear or network structure will be formed, and a three-dimensional structure cannot be formed, resulting in a surfactant with poor high-temperature stability. If the reaction temperature is too high (e.g., 60°C), the reaction time is too long (e.g., 4 hours), or the amount of silane coupling agent used is too large (e.g., a mass ratio of polyglycerol to silane coupling agent of 1:6), gelation is likely to occur during the reaction, and the resulting product cannot be used as a surfactant. If the reaction temperature is too low, the reaction time is too short, or the amount of silane coupling agent used is too small, the surfactant will not be able to form a complete three-dimensional structure, resulting in poor thermal stability of the surfactant.

[0014] Preferably, the alkoxy group is at least one of methoxy or ethoxy.

[0015] Preferably, the reaction time is 0.5 to 2 hours.

[0016] Preferably, the temperature is 25~40℃.

[0017] Preferably, the silane coupling agent has 3 to 4 alkoxy groups.

[0018] More preferably, the silane coupling agent has four alkoxy groups.

[0019] The inventors of this invention have discovered that when the number of alkoxy groups in the silane coupling agent is four, the resulting polyglycerol-modified surfactant exhibits better thermal stability.

[0020] Preferably, the polyglycerol has an average degree of polymerization of 5 to 10.

[0021] Preferably, the silane coupling agent is at least one selected from ethyl silicate, N-propyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, or γ-glycidoxypropyltrimethoxysilane.

[0022] More preferably, the silane coupling agent is ethyl silicate.

[0023] Preferably, the catalyst is at least one of dibutyltin dilaurate, dioctyltin dilaurate, diphenyl dibutyltin, or triethylstannic acid.

[0024] Preferably, the amount of catalyst used is 1 to 3‰ of the total mass of polyglycerol and silane coupling agent.

[0025] Preferably, the reaction is followed by purification and drying steps.

[0026] Preferably, the purification includes washing and extraction.

[0027] Washing is primarily for removing unreacted silane coupling agents; extraction is for separating polyglycerol and polyglycerol-modified surfactants.

[0028] More preferably, the washing and extraction process is as follows: add dichloromethane to the reaction system after the reaction is completed, stir, let stand to separate the layers, and take the upper layer; add water to the upper layer, then add acetonitrile, shake, let stand, and take the upper layer.

[0029] More preferably, the drying temperature is 70–90°C.

[0030] The present invention also protects a polyglycerol modified surfactant prepared by the above preparation method.

[0031] The present invention also protects the use of the above-mentioned polyglycerol modified surfactant in the preparation of emulsifiers, lubricants or coatings.

[0032] Preferably, the emulsifier is an emulsifier used for high-temperature cleaning.

[0033] Preferably, the coating is a high-temperature coating.

[0034] More preferably, the high temperature is 80~120℃.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] The polyglycerol modified surfactant of the present invention has an HLB value between 10 and 20, and exhibits good stability at high temperatures due to its bulk structure. Therefore, it can exert its good emulsifying effect at high temperatures and be applied to high-temperature cleaning scenarios in fields such as metal processing and automobile manufacturing. Attached Figure Description

[0037] Figure 1 Infrared spectra of decaglycerol, ethyl silicate, and the polyglycerol-modified surfactant prepared in Example 1. Detailed Implementation

[0038] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0039] Example 1

[0040] This embodiment provides a method for preparing a polyglycerol-modified surfactant, comprising the following steps:

[0041] 1) Polyglycerol, silane coupling agent and catalyst were added to a flat-bottomed beaker, mixed and reacted at 27°C for 0.5 h with stirring. During the reaction, the reaction system gradually showed a milky white gel-like appearance. The mass ratio of polyglycerol to silane coupling agent was 1:4. The polyglycerol was deca-polyglycerol, the silane coupling agent was ethyl silicate, and the catalyst was dibutyltin dilaurate. The amount of dibutyltin dilaurate was 2‰ of the total mass of polyglycerol and silane coupling agent.

[0042] 2) Add 25 mL of dichloromethane to the reaction system after the reaction in step 1), stir for 0.3 h to ensure sufficient contact between the dichloromethane and the unreacted silane coupling agent. After standing for 1 h, separation occurs. Separate the lower layer (washing solvent layer) and the upper layer (target product layer) using a separatory funnel to wash out the unreacted silane coupling agent. Add 30 mL of deionized water to the obtained upper layer, then transfer it to a separatory funnel, and add 30 mL of acetonitrile for extraction. The extraction process is as follows: shake for 5 min, stand for 1 h, and collect the upper layer. Place the upper layer in a constant temperature oven and dry at 80℃ to obtain the polyglycerol modified surfactant.

[0043] Example 2

[0044] This embodiment provides a method for preparing a polyglycerol-modified surfactant, which differs from Example 1 in that the mass ratio of polyglycerol to silane coupling agent is 1:3.

[0045] Example 3

[0046] This embodiment provides a method for preparing a polyglycerol-modified surfactant, which differs from Example 1 in that the mass ratio of polyglycerol to silane coupling agent is 1:5.

[0047] Example 4

[0048] This embodiment provides a method for preparing a polyglycerol-modified surfactant, which differs from Example 1 in that ethyl silicate is replaced with 3-methacryloyloxypropyltrimethoxysilane.

[0049] Example 5

[0050] This embodiment provides a method for preparing a polyglycerol-modified surfactant, which differs from Example 1 in that ethyl silicate is replaced with γ-glycidyl etheroxypropyltrimethoxysilane.

[0051] Example 6

[0052] This embodiment provides a method for preparing a polyglycerol modified surfactant, which differs from Example 1 in that ethyl silicate is replaced with N-propyltriethoxysilane.

[0053] Example 7

[0054] This embodiment provides a method for preparing a polyglycerol modified surfactant. The difference from Example 1 is that the temperature in step 1) is 25°C.

[0055] Example 8

[0056] This embodiment provides a method for preparing a polyglycerol modified surfactant, which differs from Embodiment 1 in that the temperature in step 1) is 40°C.

[0057] Example 9

[0058] This embodiment provides a method for preparing a polyglycerol modified surfactant, which differs from Example 1 in that the reaction in step 1) is carried out for 2 hours.

[0059] Comparative Example 1

[0060] This comparative example provides a method for preparing a polyglycerol-modified surfactant, which differs from Example 1 in that the mass ratio of polyglycerol to silane coupling agent is 1:1.

[0061] Comparative Example 2

[0062] This comparative example provides a method for preparing a polyglycerol modified surfactant, which differs from Example 1 in that the temperature in step 1) is 15°C.

[0063] Comparative Example 3

[0064] This comparative example provides a method for preparing a polyglycerol-modified surfactant. The difference from Example 1 is that the silane coupling agent is dimethyldiethoxysilane.

[0065] Comparative Example 4

[0066] This comparative example provides a method for preparing a polyethylene glycol-modified surfactant, the preparation steps of which are as follows:

[0067] S1. Maleic anhydride, polyethylene glycol (average degree of polymerization 16), and titanium isopropoxide catalyst are polymerized at 200°C to obtain maleic anhydride-polyethylene glycol. The mass ratio of maleic anhydride to polyethylene glycol is 1:2, and the amount of titanium isopropoxide catalyst is 2‰ of the total mass of polyethylene glycol and maleic anhydride.

[0068] S2. Maleic anhydride-polyethylene glycol, ethyl silicate, and titanium isopropoxide catalyst were reacted at 125℃ for 4 h to obtain a polyethylene glycol-modified surfactant. The mass ratio of maleic anhydride-polyethylene glycol to ethyl silicate was 1:4, and the amount of titanium isopropoxide catalyst was 2‰ of the total mass of maleic anhydride-polyethylene glycol and ethyl silicate.

[0069] Characterization and performance testing

[0070] 1. Sample characterization

[0071] Fourier transform infrared spectroscopy (FTIR) was performed on decaglycerol, ethyl silicate, and the polyglycerol-modified surfactants prepared in each example. The polyglycerol organosilicon surfactants prepared in the experiment were viscous liquids and could be directly measured using the KBr smear method. After obtaining the background spectrum, a small amount of the product was coated onto the surface of a KBr slide and then placed in the sample chamber for infrared spectroscopy scanning. Figure 1 Infrared spectra of decaglycerol, ethyl silicate, and the polyglycerol-modified surfactant prepared in Example 1.

[0072] from Figure 1 It can be known that 1124 cm -1 A characteristic Si-O-Si peak appears at 3360 cm⁻¹. -1 The peak at 2902 cm⁻¹ is the -OH peak. -1 The peak shown at 1078 cm⁻¹ is a CH stretching vibration peak, indicating that ethyl silicate undergoes hydrolysis to produce silicic acid and ethanol, followed by a condensation reaction of silicic acid and silicic acid to form polysiloxane segments, hence the characteristic Si-O-Si peak. This peak is similar to that of ethyl silicate at 1078 cm⁻¹. -1 Compared to the Si-OC characteristic peak appearing at 1054 cm⁻¹, the polyglycerol-modified surfactant of Example 1 showed a peak at 1054 cm⁻¹. -1The appearance of the Si-OC characteristic peak, i.e., a blue shift of the Si-OC characteristic peak, indicates that the alkoxy group of ethyl silicate reacts with the hydroxyl group of polyglycerol to form a Si-OC bond, meaning that ethyl silicate and polyglycerol have reacted. The infrared spectra of other embodiments are similar to those of Example 1, indicating that reactions occurred between the silane coupling agents and between the silane coupling agents and polyglycerol, thereby obtaining the polyglycerol-modified surfactant of the present invention.

[0073] 2. Determination of HLB value

[0074] The HLB values ​​of samples from each embodiment and comparative example were tested using an emulsification method. Span 80 (HLB: 4.3) and Tween 80 (HLB: 15) were mixed at a specific mass ratio to prepare oil phases with different HLB values. Water, surfactant, and oil phases with different HLB values ​​were mixed evenly at a mass ratio of 80:5:15, and the emulsification effect was observed. The emulsion sample with the best emulsification effect was selected, and its corresponding HLB value was taken as the HLB value of the sample. The results are shown in Table 1.

[0075] 3. Determination of thermal stability

[0076] The emulsion samples with the best emulsification effect in the above HLB value determination were placed in a temperature control chamber and placed at 100℃ for 10 h. The emulsion was observed to see if there was any separation every 2 h. The results are shown in Table 1.

[0077] Table 1. HLB values ​​and thermal stability test results of surfactants in each example and comparative example.

[0078]

[0079] As shown in Table 1, the HLB values ​​of the polyglycerol modified surfactants prepared in each embodiment are all between 10 and 20. In addition, under high temperature conditions, the emulsion samples of the polyglycerol modified surfactants prepared in each embodiment can remain stable without separation within 8 hours, indicating that the polyglycerol modified surfactant of the present invention has good thermal stability and can exert its good emulsifying effect at high temperatures, making it suitable for high-temperature cleaning scenarios in fields such as metal processing and automobile manufacturing.

[0080] The amount of silane coupling agent used in Comparative Example 1 was too small or the reaction temperature in Comparative Example 2 was too low, so the polyglycerol modified surfactant was not enough to form a complete three-dimensional structure. The emulsion samples prepared by them separated into layers within 6 h and 4 h under high temperature conditions, respectively, indicating that the thermal stability of the surfactants in Comparative Example 1 and Comparative Example 2 was poor.

[0081] The silane coupling agent used in Comparative Example 3 had two alkoxy groups, and the emulsion sample prepared with its surfactant separated into layers within 4 hours, indicating that it had poor stability at high temperatures.

[0082] Comparative Example 4 was not suitable for using other hydrophilic modifiers (polyethylene glycol). The emulsion sample prepared with its surfactant separated into layers within 4 hours, indicating that its stability at high temperatures was not bad.

[0083] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a polyglycerol-modified surfactant, characterized in that, Includes the following steps: Polyglycerol, silane coupling agent and catalyst are mixed and reacted at 22~40℃ for 0.1~2 h to obtain the polyglycerol modified surfactant. The mass ratio of the polyglycerol to the silane coupling agent is 1:3~5; The silane coupling agent has ≥3 alkoxy groups.

2. The preparation method according to claim 1, characterized in that, The reaction time is 0.5 to 2 hours.

3. The preparation method according to claim 1, characterized in that, The silane coupling agent has 3 to 4 alkoxy groups.

4. The preparation method according to claim 1, characterized in that, The polyglycerol has an average degree of polymerization of 5 to 10.

5. The preparation method according to claim 1, characterized in that, The silane coupling agent is at least one of ethyl silicate, N-propyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, or γ-glycidoxypropyltrimethoxysilane.

6. The preparation method according to claim 1, characterized in that, The catalyst is at least one of dibutyltin dilaurate, dioctyltin dilaurate, diphenyl dibutyltin, or triethylstannic acid.

7. The preparation method according to claim 1, characterized in that, The amount of catalyst used is 1 to 3‰ of the total mass of polyglycerol and silane coupling agent.

8. The preparation method according to claim 1, characterized in that, The reaction is followed by purification and drying steps.

9. A polyglycerol-modified surfactant, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 8.

10. The use of the polyglycerol modified surfactant of claim 9 in the preparation of emulsifiers, lubricants or coatings.

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