Polyglycerol modified surfactant as well as preparation method and application thereof

Abstract

The invention relates to a polyglycerol modified surfactant as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing polyglycerol, a silane coupling agent and a catalyst, and reacting at 22-40 DEG C for 0.1-2 hours to obtain the polyglycerol modified surfactant, the mass ratio of the polyglycerol to the silane coupling agent is 1: (3-5); the number of alkoxy groups in the silane coupling agent is greater than or equal to 3. The HLB (Hydrophile-Lipophile Balance) of the polyglycerol modified surfactant is between 10 and 20, and the polyglycerol modified surfactant has good stability at high temperature due to the characteristics of a body structure, so that the polyglycerol modified surfactant can play a good emulsifying role at high temperature, and is applied to high-temperature cleaning scenes in the fields of metal processing, automobile manufacturing and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of surfactants, and more specifically, to a polyglycerol modified surfactant and a preparation method and application thereof. Background Art

[0002] In the fields of metal processing and automobile manufacturing, it is often necessary to clean parts at high temperatures, and cleaning agents are usually used repeatedly and for long periods of time. In these high-temperature cleaning scenarios, surfactants with high HLB values ​​(10-20) are required. Currently, anionic surfactants such as sulfonates and carboxylates are mainly used. However, these anionic surfactants have a certain corrosive effect on metal materials, which can easily cause corrosion to cleaning equipment, and these anionic surfactants may pollute the environment.

[0003] Silicone surfactants have the advantages of low or even non-toxicity to the human body, mild nature, excellent physical and chemical properties, and strong plasticity, and are often used in the fields of cosmetics. Silicone surfactants are mainly obtained by introducing hydrophilic groups or hydrophilic segments (such as polyether segments) into polysiloxane segments, such as the Chinese patent named Silicone Surfactants and Preparation Methods and Applications thereof. The HLB value of existing silicone surfactants can usually reach 10~20, which meets the requirements for use in cleaning scenarios in daily life. However, existing silicone surfactants are prone to decomposition at high temperatures, thereby reducing their cleaning efficiency, and therefore are difficult to use in high-temperature cleaning scenarios in metal processing, automobile manufacturing and other fields. Summary of the invention

[0004] The primary purpose of the present invention is to overcome the problem of poor high temperature resistance of existing organosilicon surfactants and provide a method for preparing a polyglycerol modified surfactant. The HLB of the polyglycerol modified surfactant is between 10 and 20, and due to the characteristics of its body structure, it has good stability at high temperatures, so that it can exert its good emulsification effect at high temperatures and is applied to high temperature cleaning scenarios in the fields of metal processing, automobile manufacturing, etc.

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

[0006] Another object of the present invention is to provide a use of a polyglycerol-modified surfactant in the preparation of an emulsifier, a lubricant or a coating.

[0007] The above-mentioned object of the present invention is achieved by the following technical solutions: A method for preparing a polyglycerol modified surfactant comprises the following steps: The polyglycerol, silane coupling agent and catalyst are mixed and reacted at a temperature of 22-40° C. 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 number of alkoxy groups of the silane coupling agent is ≥3.

[0008] The inventors of the present invention have found through research that when polyglycerol and silane coupling agents react at a certain temperature and time, on the one hand, a hydrolysis condensation reaction can occur between the silane coupling agents to form polysiloxane segments, and on the other hand, a condensation reaction can occur by utilizing the characteristics of the polyhydroxy structure of polyglycerol and the multiple alkoxy groups of the silane coupling agent to form a polyglycerol-modified surfactant with a three-dimensional structure. The HLB of the polyglycerol-modified surfactant is between 10 and 20, and due to the characteristics of the three-dimensional structure, it has good stability at high temperatures, so that it can exert its good emulsification effect at high temperatures and is applied to high-temperature cleaning scenarios in the fields of metal processing and automobile manufacturing.

[0009] If the number of alkoxy groups of the selected silane coupling agent is 2 or other hydrophilic modifiers (such as polyethylene glycol) are selected, a linear structure or a network structure is formed, and a three-dimensional structure cannot be formed, and the obtained surfactant has poor high-temperature stability. If the reaction temperature is too high (for example, 60°C), the reaction time is too long (for example, 4 h) or the amount of silane coupling agent is too large (for example, the mass ratio of polyglycerol to silane coupling agent is 1:6), it is easy to gel during the reaction, and the obtained 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 is too little, the surfactant is not enough to form a relatively complete three-dimensional structure, resulting in poor thermal stability of the surfactant.

[0010] Preferably, the alkoxy group is at least one of a methoxy group and an ethoxy group.

[0011] Preferably, the reaction time is 0.5 to 2 h.

[0012] Preferably, the temperature is 25-40°C.

[0013] Preferably, the silane coupling agent has 3 to 4 alkoxy groups.

[0014] More preferably, the silane coupling agent has four alkoxy groups.

[0015] The inventors of the present invention have found that when the number of alkoxy groups of the silane coupling agent is 4, the obtained polyglycerol-modified surfactant has better thermal stability.

[0016] Preferably, the average degree of polymerization of the polyglycerol is 5 to 10.

[0017] Preferably, the silane coupling agent is at least one of ethyl silicate, N-propyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane or γ-glycidyloxypropyltrimethoxysilane.

[0018] More preferably, the silane coupling agent is ethyl silicate.

[0019] Preferably, the catalyst is at least one of dibutyltin dilaurate, dioctyltin dilaurate, diphenyldibutyltin or triethylstannoic acid.

[0020] Preferably, the amount of the catalyst is 1-3‰ of the total mass of polyglycerol and silane coupling agent.

[0021] Preferably, after the reaction, purification and drying steps are also included.

[0022] Preferably, the purification comprises washing and extraction.

[0023] The washing is mainly to remove the unreacted silane coupling agent; the extraction is to separate the polyglycerol and the polyglycerol-modified surfactant.

[0024] More preferably, the washing and extraction process is: adding dichloromethane to the reaction system after the reaction is completed, stirring, standing to separate layers, and taking the upper layer liquid; adding water to the upper layer liquid, then adding acetonitrile, shaking, standing, and taking the upper layer liquid. More preferably, the drying temperature is 70-90°C.

[0025] The present invention also protects a polyglycerol modified surfactant prepared by the above preparation method.

[0026] The present invention also protects the use of the polyglycerol modified surfactant in the preparation of emulsifiers, lubricants or coatings.

[0027] Preferably, the emulsifier is an emulsifier for high temperature cleaning.

[0028] Preferably, the coating is a high temperature coating.

[0029] More preferably, the high temperature is 80-120°C.

[0030] Compared with the prior art, the present invention has the following beneficial effects: The HLB of the polyglycerol-modified surfactant of the present invention is between 10 and 20, and due to the characteristics of its body structure, it has good stability at high temperatures, so that it can exert its good emulsification effect at high temperatures and is applied to high-temperature cleaning scenarios in the fields of metal processing, automobile manufacturing, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1The infrared spectra of decaglycerol, ethyl silicate and the polyglycerol modified surfactant prepared in Example 1 are shown. DETAILED DESCRIPTION

[0032] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0033] Example 1 This embodiment provides a method for preparing a polyglycerol modified surfactant, comprising the following steps: 1) Add polyglycerol, silane coupling agent and catalyst into a flat-bottom beaker, mix, and react for 0.5 h under stirring at 27°C. During the reaction, the reaction system gradually presents a milky white gel appearance. The mass ratio of polyglycerol to silane coupling agent is 1:4, the polyglycerol is decaglycerol, the silane coupling agent is ethyl silicate, the catalyst is dibutyltin dilaurate, and the amount of dibutyltin dilaurate is 2‰ of the total mass of polyglycerol and silane coupling agent. 2) Add 25 mL of dichloromethane to the reaction system after the reaction in step 1) and stir for 0.3 h to allow the dichloromethane to fully contact with the unreacted silane coupling agent. After standing for 1 h, the system separates. Use a separatory funnel to separate the lower liquid (washing solvent layer) and the upper liquid (target product layer) to wash out the unreacted silane coupling agent. Add 30 mL of deionized water to the upper liquid, then transfer it to a separatory funnel, and then add 30 mL of acetonitrile for extraction; the extraction process is: shake for 5 min, stand for 1 h, take the upper liquid; place the upper liquid in a constant temperature oven and dry it at 80°C to obtain a polyglycerol modified surfactant.

[0034] Example 2 This embodiment provides a method for preparing a polyglycerol-modified surfactant. The difference from Embodiment 1 is that the mass ratio of polyglycerol to silane coupling agent is 1:3.

[0035] Example 3 This embodiment provides a method for preparing a polyglycerol-modified surfactant. The difference from Embodiment 1 is that the mass ratio of polyglycerol to silane coupling agent is 1:5.

[0036] Example 4 This embodiment provides a method for preparing a polyglycerol-modified surfactant. The difference from Embodiment 1 is that ethyl silicate is replaced by 3-methacryloxypropyltrimethoxysilane.

[0037] Example 5 This embodiment provides a method for preparing a polyglycerol-modified surfactant. The difference from Embodiment 1 is that ethyl silicate is replaced by γ-glycidyloxypropyltrimethoxysilane.

[0038] Example 6 This embodiment provides a method for preparing a polyglycerol-modified surfactant. The difference from Embodiment 1 is that ethyl silicate is replaced by N-propyltriethoxysilane.

[0039] Example 7 This embodiment provides a method for preparing a polyglycerol-modified surfactant. The difference from Embodiment 1 is that the temperature in step 1) is 25°C.

[0040] Example 8 This embodiment provides a method for preparing a polyglycerol modified surfactant. The difference from Embodiment 1 is that the temperature in step 1) is 40°C.

[0041] Example 9 This embodiment provides a method for preparing a polyglycerol-modified surfactant. The difference from Embodiment 1 is that the reaction in step 1) is carried out for 2 h.

[0042] Comparative Example 1 This comparative example provides a method for preparing a polyglycerol-modified surfactant. The difference from Example 1 is that the mass ratio of polyglycerol to silane coupling agent is 1:1.

[0043] Comparative Example 2 This comparative example provides a method for preparing a polyglycerol-modified surfactant. The difference from Example 1 is that the temperature in step 1) is 15°C.

[0044] Comparative Example 3 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.

[0045] Comparative Example 4 This comparative example provides a method for preparing a polyethylene glycol-modified surfactant, and the preparation steps are as follows: S1. Maleic anhydride, polyethylene glycol (average degree of polymerization is 16) and catalyst titanium isopropoxide 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 catalyst titanium isopropoxide is 2‰ of the total mass of polyethylene glycol and maleic anhydride.

[0046] S2. Maleic anhydride-polyethylene glycol, ethyl silicate and catalyst titanium isopropoxide are reacted at 125°C for 4 h to obtain a polyethylene glycol-modified surfactant, wherein the mass ratio of maleic anhydride-polyethylene glycol to ethyl silicate is 1:4, and the amount of catalyst titanium isopropoxide is 2‰ of the total mass of maleic anhydride-polyethylene glycol and ethyl silicate.

[0047] Characterization and performance testing 1. Sample characterization Decaglycerol, ethyl silicate and the polyglycerol modified surfactant prepared in each embodiment were tested by Fourier infrared spectroscopy. The polyglycerol organosilicon surfactant prepared in the experiment was a viscous liquid and could be directly measured by the KBr smear method. After measuring the background spectrum, a small amount of the product was coated on the surface of the KBr sheet, and then placed in the sample chamber for infrared spectrum scanning. Figure 1 The infrared spectra of decaglycerol, ethyl silicate and the polyglycerol modified surfactant prepared in Example 1 are shown.

[0048] from Figure 1 It can be seen that 1124 cm -1 The Si-O-Si characteristic peak appears at 3360 cm -1 The peak at 2902 cm -1 The peak of CH stretching vibration is shown at 1078 cm, indicating that ethyl silicate undergoes hydrolysis to generate silicic acid and ethanol, followed by silicic acid condensation to form polysiloxane segments, resulting in the appearance of Si-O-Si characteristic peaks; -1 Compared with the Si-OC characteristic peak at 1054 cm -1 The Si-OC characteristic peak appears at , that is, the Si-OC characteristic peak is blue-shifted, indicating that the alkoxy group of ethyl silicate reacts with the hydroxyl group of polyglycerol to form a Si-OC bond, that is, ethyl silicate and polyglycerol react. The infrared spectra of other embodiments are similar to that of embodiment 1, indicating that the silane coupling agents react with each other, and the silane coupling agents and polyglycerol also react with each other, thereby obtaining the polyglycerol modified surfactant of the present invention.

[0049] 2. Determination of HLB value The HLB values ​​of the samples of the embodiments and comparative examples were tested by emulsification method. Span 80 (HLB: 4.3) and Tween 80 (HLB: 15) were mixed in a certain mass ratio to prepare oil phases with different HLB values. Water, surfactants and oil phases with different HLB values ​​were mixed evenly in a mass ratio of 80:5:15, and the emulsification effect was observed. The emulsion sample with the best emulsification effect was selected, and the HLB value corresponding to the oil was the HLB value of the sample. The results are shown in Table 1.

[0050] 3. Determination of thermal stability The emulsion samples with the best emulsification effect in the above HLB value determination were placed in a temperature-controlled box at 100°C for 10 h, and the emulsion was observed every 2 h to see if there was any stratification. The results are shown in Table 1.

[0051] Table 1 HLB values ​​and thermal stability test results of surfactants in various embodiments and comparative examples

[0052] As can be seen from Table 1, the HLB of the polyglycerol-modified surfactants prepared in each embodiment is between 10 and 20. In addition, under high temperature environment, the emulsion samples of the polyglycerol-modified surfactants prepared in each embodiment can be stable without stratification within 8 hours, indicating that the polyglycerol-modified surfactants of the present invention have good thermal stability and can exert their good emulsification effect at high temperature, and are applied to high-temperature cleaning scenarios in the fields of metal processing, automobile manufacturing, etc.

[0053] In Comparative Example 1, the amount of silane coupling agent used is too small or the reaction temperature in Comparative Example 2 is too low, and the obtained polyglycerol-modified surfactant is insufficient to form a relatively complete body structure. The obtained emulsion samples are stratified within 6 h and 4 h respectively under high temperature conditions, indicating that the thermal stability of the surfactants in Comparative Examples 1 and 2 is poor.

[0054] The silane coupling agent selected in Comparative Example 3 has two alkoxy groups, and the emulsion sample prepared with the surfactant delaminated within 4 hours, indicating that it has poor stability at high temperatures.

[0055] In Comparative Example 4, the use of other hydrophilic modifiers (polyethylene glycol) is not appropriate. The emulsion sample prepared with the surfactant stratifies within 4 hours, indicating that its stability at high temperature is not bad.

[0056] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a polyglycerol modified surfactant, characterized in that: The following steps are involved: The polyglycerol, silane coupling agent and catalyst are mixed and reacted at a temperature of 22-40° C. 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 number of alkoxy groups of the silane coupling agent is ≥3.

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

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 average polymerization degree of the polyglycerol is 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-propyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane or γ-glycidyloxypropyl trimethoxysilane.

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

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

8. The preparation method according to claim 1, characterized in that: After the reaction, purification and drying steps are also included.

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

10. Use of the polyglycerol modified surfactant according to claim 9 in the preparation of an emulsifier, a lubricant or a coating.

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