Universal surfactant and preparation method thereof

Abstract

The invention provides a universal surfactant and a preparation method thereof.The preparation method of the universal surfactant comprises the following steps that S1, a titanate cross-linking agent and a silane coupling agent are mixed and stirred, and a first mixture is obtained; s2, adding a hydrocarbon solvent into the first mixture, and stirring to obtain a turbid second mixture; s3, adding an alcohol solvent into the second mixture, and stirring to obtain a clarified third mixture; and S4, adding a catalyst into the third mixture, and stirring to obtain the universal surfactant. The universal surfactant is non-corrosive, has wide applicability to various base materials and adhesives, can effectively improve the bonding performance of low-surface-energy base materials, and integrates the polyurethane adhesive and the silica gel, and the preparation method is simple, stable and controllable, clear in process index and convenient for industrial large-scale production and popularization.

Description

Technical Field

[0001] This invention belongs to the field of adhesive pretreatment technology, specifically relating to a general-purpose surfactant and its preparation method. Background Technology

[0002] Adhesive technology is increasingly widely used in fields such as electronic equipment, automobile manufacturing, home appliances, and building decoration. However, for low surface energy substrates such as glass, paint, galvanized steel, PP, and PVC, which have strong chemical inertness and poor wettability, direct application of adhesives often results in ineffective spreading and penetration, leading to low bond strength, interface damage, and even debonding. To ensure reliable bonding, surface treatment agents are typically used to wet and activate the substrate surface, removing contaminants, increasing surface energy, and forming an active layer that can chemically bond with the adhesive.

[0003] In existing technologies, commonly used surface treatment agents include polyisocyanate-based polyurethane primers and silane coupling agent-based activators. While polyurethane primers can improve the adhesion of single-component polyurethane adhesives, they suffer from poor storage stability (due to the presence of highly active components), significant pollution (containing solvents such as methyl ethyl ketone and toluene), and poor compatibility with low surface energy substrates (such as glass and oil-based painted panels) and other sealants. Compared to polyurethane primers, silane coupling agent-based activators offer greater advantages. They are primarily composed of silane coupling agents and solvents, featuring simple composition, good storage stability, broad compatibility, and solvent friendliness, making them more promising for practical applications. However, existing silane coupling agent-based activators exhibit problems such as corroding stainless steel and other metal substrates, limited activation and adhesion-enhancing effects on low surface energy substrates, and difficulty in simultaneously addressing the needs of both polyurethane and silicone adhesives. Summary of the Invention

[0004] In view of this, the present invention provides a general-purpose surfactant and its preparation method, which is non-corrosive, has wide applicability to a variety of substrates and adhesives, can effectively improve the bonding performance of low surface energy substrates, and is compatible with both polyurethane adhesives and silicone adhesives. Moreover, the preparation method is simple, stable and controllable, with clear process indicators, which is convenient for large-scale industrial production and promotion.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a general-purpose surfactant, comprising the following steps: S1. Mix the titanate crosslinking agent and the silane coupling agent, and stir to obtain the first mixture; S2. Add a hydrocarbon solvent to the first mixture and stir to obtain a turbid second mixture; S3. Add an alcohol solvent to the second mixture and stir to obtain a clear third mixture; S4. Add the catalyst to the third mixture and stir to obtain a general-purpose surfactant.

[0006] Preferably, in the raw materials for preparing the general-purpose surfactant, the mass percentages of the alcohol solvent, the hydrocarbon solvent, the titanate crosslinking agent, the silane coupling agent, and the catalyst are 5-15%, 80-90%, 1-5%, 1-5%, and 0.1-1%, respectively.

[0007] Preferably, in step S1, the stirring speed is 200~400 rpm and the time is 8~15 min; and / or, In step S2, the stirring speed is 200~400 rpm, and the time is 20~30 min; and / or, In step S3, the stirring speed is 200~400 rpm, and the time is 5~10 min; and / or, In step S4, the stirring speed is 200~400 rpm and the time is 3~5 min.

[0008] Preferably, in steps S1 to S4, stirring is carried out under a nitrogen atmosphere.

[0009] Preferably, the titanate crosslinking agent includes at least one of isopropyltris(dodecylbenzenesulfonyloxy) titanate and isopropyltris(dioctylpyrophosphateoxy) titanate.

[0010] Preferably, the silane coupling agent comprises at least one of γ-aminopropyltriethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0011] Preferably, the catalyst comprises at least one of dibutyltin dilaurate and dibutyltin acetate.

[0012] Preferably, the alcohol solvent includes at least one of ethanol, isopropanol, and methanol.

[0013] Preferably, the hydrocarbon solvent includes at least one of n-heptane and cyclohexane.

[0014] Secondly, the present invention also provides a general-purpose surfactant prepared by the aforementioned preparation method.

[0015] Thirdly, the present invention also provides the application of the general-purpose surfactant in the bonding of a substrate and an adhesive layer.

[0016] Preferably, the substrate includes glass, galvanized sheet, stainless steel sheet, painted sheet, PP sheet, and PVC sheet.

[0017] Preferably, the adhesive layer comprises a one-component polyurethane sealant or a silicone sealant.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The general-purpose surface activator provided by the present invention forms a stable coupling agent activation layer on the surface of the substrate, thereby changing the bonding form between the substrate and the adhesive from physical adsorption to chemical bonding, which significantly increases the proportion of cohesive failure (CF) and improves the bonding reliability; at the same time, it is free of acidic components, which can avoid the corrosion risk when processing metal substrates such as stainless steel; and achieve more reliable interface bonding and corrosion resistance.

[0019] (2) The general-purpose surface activator provided by the present invention, through the compounding of titanate crosslinking agent, silane coupling agent and catalyst, as well as the combination of polar solvent and non-polar solvent, can be applied to low surface energy non-metallic substrates such as glass, paint, galvanized sheet, PP, PVC and stainless steel metal substrates, and exhibits good adhesion promoting effect on polyurethane sealant and silicone sealant; it has wide applicability to a variety of substrates and adhesives.

[0020] (3) The general-purpose surfactant provided by the present invention utilizes the polarity difference of the two solvents and the specific process feeding sequence to use the clear physical state change of "turbidity-clarity" as a quality control indicator, and promotes the efficient compounding of active components, ensuring the uniformity and stability between product batches, which is convenient for large-scale industrial production and promotion. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention. Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art, and all reagents and consumables are commercially available products.

[0022] Example 1 This embodiment provides a general-purpose surfactant prepared from the following raw materials in the indicated mass percentages: 9.5% anhydrous ethanol, 84.0% n-heptane, 3.0% isopropyltris(dioctylpyrophosphoryloxy)titanate, 3.0% γ-aminopropyltriethoxysilane, and 0.5% dibutyltin dilaurate; the preparation steps are as follows: 1. In a dry and clean reaction vessel, add isopropyltris(dioctylpyrophosphoryloxy)titanate and γ-aminopropyltriethoxysilane, introduce nitrogen gas with a purity greater than 95%, start stirring, control the speed at 300 rpm, and continue stirring for 10 minutes to obtain the first mixture. 2. Add n-heptane to the first mixture above, maintain a speed of 300 rpm, and continue stirring for 20 minutes. It can be observed that the mixture becomes slightly turbid, thus obtaining a slightly turbid second mixture. 3. Add anhydrous ethanol to the slightly turbid second mixture and stir for 5 minutes while maintaining a speed of 300 rpm. You can observe that the mixture gradually becomes clear and transparent, thus obtaining a clear third mixture. 4. Add dibutyltin dilaurate to the clarified third mixture above, maintain a speed of 300 rpm, and continue stirring for 3 minutes to ensure that the dibutyltin dilaurate is completely and evenly dispersed; 5. Discharge the material, seal and package it to obtain the final product.

[0023] Example 2 This embodiment provides a general-purpose surfactant prepared from the following raw materials in the indicated mass percentages: 9.5% anhydrous ethanol, 84.0% n-heptane, 1.0% isopropyltris(dioctylpyrophosphoryloxy)titanate, 5.0% γ-aminopropyltriethoxysilane, and 0.5% dibutyltin dilaurate. The preparation method is the same as in Example 1, and the "turbidity-clarity" phenomenon is also observed.

[0024] Example 3 This embodiment provides a general-purpose surfactant prepared from the following raw materials in the indicated mass percentages: 9.5% anhydrous ethanol, 84.0% n-heptane, 2.0% isopropyltris(dodecylbenzenesulfonyloxy)titanate, 4.0% N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and 0.5% dibutyltin dilaurate. The preparation method is the same as in Example 1, and the "turbidity-clarity" phenomenon is also observed.

[0025] Example 4 This embodiment provides a general-purpose surfactant prepared from the following raw materials in the indicated mass percentages: 9.5% anhydrous ethanol, 84.4% n-heptane, 3.0% isopropyltris(dioctylpyrophosphoryloxy)titanate, 3.0% γ-aminopropyltriethoxysilane, and 0.1% dibutyltin acetate. The preparation method is the same as in Example 1, and the "turbidity-clarity" phenomenon is also observed.

[0026] Example 5 This embodiment provides a general-purpose surfactant prepared from the following raw materials in the indicated mass percentages: 4.0% anhydrous methanol, 8.0% anhydrous ethanol, 80.0% cyclohexane, 3.5% isopropyltris(dioctylpyrophosphoryloxy)titanate, 4.0% γ-aminopropyltriethoxysilane, and 0.5% dibutyltin dilaurate. The preparation method is the same as in Example 1, and the "turbidity-clarity" phenomenon is also observed.

[0027] Comparative Example 1 This comparative example provides a surfactant prepared from the following raw materials in the indicated mass percentages: 9.5% anhydrous ethanol, 87.0% n-heptane, 3.0% γ-aminopropyltriethoxysilane, and 0.5% dibutyltin dilaurate. The preparation method is essentially the same as in Example 1, except that step 1 is omitted. In step 2, γ-aminopropyltriethoxysilane and n-heptane are added to a reaction vessel, nitrogen gas with a purity greater than 95% is introduced, stirring is started, and the stirring speed is controlled at 300 rpm for 20 minutes. No obvious turbidity was observed in the mixture during preparation.

[0028] Comparative Example 2 This comparative example provides a surfactant prepared from the following raw materials in the indicated mass percentages: 9.5% anhydrous ethanol, 87.0% n-heptane, 3.0% isopropyltris(dioctylpyrophosphoryloxy)titanate, and 0.5% dibutyltin dilaurate. The preparation method is essentially the same as in Example 1, except that step 1 is omitted. In step 2, isopropyltris(dioctylpyrophosphoryloxy)titanate and n-heptane are added to a reaction vessel, nitrogen gas with a purity greater than 95% is introduced, stirring is started, and the stirring speed is controlled at 300 rpm for 20 minutes. The mixture remains clear throughout the preparation process.

[0029] Comparative Example 3 This comparative example provides a surfactant prepared from the following raw materials in the indicated mass percentages: 9.5% anhydrous ethanol, 84.5% n-heptane, 3.0% isopropyltris(dioctylpyrophosphoryloxy)titanate, and 3.0% γ-aminopropyltriethoxysilane. The preparation method is basically the same as that in Example 1, except that step 4 is not performed, and the mixture remains clear throughout the preparation process.

[0030] Comparative Example 4 This comparative example provides a surfactant prepared from the following raw materials in the indicated mass percentages: 93.5% n-heptane, 3.0% isopropyltris(dioctylpyrophosphoryloxy)titanate, 3.0% γ-aminopropyltriethoxysilane, and 0.5% dibutyltin dilaurate. The preparation method is essentially the same as in Example 1, except that step 3 is omitted. In step 4, dibutyltin dilaurate is added to the slightly turbid second mixture, and the mixture is stirred at 300 rpm for 3 minutes to ensure complete and uniform dispersion of the dibutyltin dilaurate. The mixture did not become clear during the preparation process.

[0031] Comparative Example 5 This comparative example provides a surfactant prepared from the following raw materials in the indicated mass percentages: 94.9% isopropanol, 0.1% hydrochloric acid, 3.0% n-butyl titanate, and 2.0% 3-(2,3-epoxypropoxy)propyltrimethoxysilane; the preparation steps are as follows: 1. In a dry and clean reaction vessel, add a portion of isopropanol (50% by mass) and hydrochloric acid, start stirring, and continue stirring for 20 minutes to obtain the first mixture; 2. Add tetrabutyl titanate and 3-(2,3-epoxypropoxy)propyltrimethoxysilane to the first mixture above within 2 minutes, purge with nitrogen gas of greater than 95% purity, and continue stirring for 20 minutes to obtain the second mixture; 3. Add the remaining isopropanol (44.9% by mass) to the second mixture above and continue stirring for 20 minutes; 4. Discharge the material, seal and package it to obtain the final product.

[0032] Performance Tests and Results The surfactants of Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests, and the test methods are as follows: 1. Adhesive and substrate compatibility bonding: (1) Test substrates: float glass, painted sheet, galvanized sheet, 304 stainless steel sheet, PP sheet, PVC sheet; (2) Adhesives used in the test: single-component polyurethane adhesive (PU adhesive) and silicone adhesive (silicone adhesive) from Huitian New Materials Co., Ltd. (3) Test procedure: First, wipe the substrate surface clean with isopropyl alcohol, and after it evaporates and dries, apply the surface activator and let it dry at room temperature for 3-5 minutes; then prepare the corresponding adhesive for application and cure for 7 days under standard conditions (23±2℃, 55%RH); (4) Test standard: Refer to GB / T 43747-2024 to test the adhesion of the adhesive to the substrate, and observe the failure mode (CF: cohesive failure; AF: interfacial failure) and the bonding ratio.

[0033] 2. Corrosion test: Apply the surfactant to the surface of the newly polished 304 stainless steel plate, and then place it in a constant temperature and humidity chamber (23±2℃, 55%RH) for 168 hours. Observe whether there are rust spots or corrosion marks on the surface; if there are no rust spots or corrosion marks, the corrosion test is passed.

[0034] The test results for each surfactant are shown in Table 1.

[0035] Table 1. Surfactant performance test results

[0036] As can be seen from Table 1, compared with Comparative Example 5, the general-purpose surfactants of Examples 1-5 showed no rust on the stainless steel plate and achieved a high proportion of cohesive failure (≥95% CF). This indicates that the general-purpose surfactant provided by the present invention ensures bonding reliability while avoiding corrosion risks, and has both non-corrosiveness and high bonding strength. The surfactant in Comparative Example 1 showed complete interfacial disruption on the PP board, while the surfactant in Comparative Example 2 exhibited a sharp drop in adhesion on glass. Furthermore, the surfactants in Comparative Examples 1-4 showed low cohesive disruption rates (≤85%) on all tested substrates (glass, painted panels, galvanized sheets, stainless steel sheets, PP boards, PVC boards) and adhesives (PU glue, silicone). The general-purpose surfactants in Examples 1-5 demonstrated high and balanced cohesive disruption rates (≥90% CF) on all tested substrates and adhesives. This indicates that the general-purpose surfactant provided by this invention has a synergistic effect among its components, achieving broad applicability to various substrates and adhesives. Comparative Example 4 failed to complete the "turbid-clarified" transformation during preparation, and the adhesive properties (cohesion destruction rate of 30%~85%) of the obtained surfactant were lower than those of Examples 1~5; indicating that the specific feeding sequence of the present invention is not only a quality control indicator, but also a key process guarantee for achieving efficient compounding of active components and obtaining high-performance products.

[0037] In summary, the universal surfactant provided by this invention is non-corrosive and has wide applicability to a variety of substrates and adhesives. It can avoid the corrosion risk of metal substrates such as stainless steel, and enable a variety of substrates (glass, painted board, galvanized board, stainless steel board, PP board, PVC board) including low surface area substrates to form a high-strength chemical bond with adhesives (PU adhesive, silicone). Moreover, the preparation method is simple, stable and controllable, and the process indicators are clear, which is convenient for large-scale industrial production and promotion.

[0038] Unless otherwise specified, all raw materials used in this invention are existing substances that can be purchased directly from the market.

[0039] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a general-purpose surfactant, characterized in that, Includes the following steps: S1. Mix the titanate crosslinking agent and the silane coupling agent, and stir to obtain the first mixture; S2. Add a hydrocarbon solvent to the first mixture and stir to obtain a turbid second mixture; S3. Add an alcohol solvent to the second mixture and stir to obtain a clear third mixture; S4. Add the catalyst to the third mixture and stir to obtain a general-purpose surfactant.

2. The method for preparing the general-purpose surfactant according to claim 1, characterized in that, In the raw materials for preparing the general-purpose surfactant, the mass percentages of the alcohol solvent, the hydrocarbon solvent, the titanate crosslinking agent, the silane coupling agent, and the catalyst are 5-15%, 80-90%, 1-5%, 1-5%, and 0.1-1%, respectively.

3. The method for preparing the general-purpose surfactant according to claim 1, characterized in that, In step S1, the stirring speed is 200~400 rpm, and the time is 8~15 min; and / or, In step S2, the stirring speed is 200~400 rpm, and the time is 20~30 min; and / or, In step S3, the stirring speed is 200~400 rpm, and the time is 5~10 min; and / or, In step S4, the stirring speed is 200~400 rpm and the time is 3~5 min.

4. The method for preparing the general-purpose surfactant according to claim 1, characterized in that, In steps S1 to S4, stirring is carried out under a nitrogen atmosphere.

5. The method for preparing the general-purpose surfactant according to claim 1, characterized in that, The titanate crosslinking agent includes at least one of isopropyl tris(dodecylbenzenesulfonyloxy) titanate and isopropyl tris(dioctylpyrophosphateoxy) titanate.

6. The method for preparing the general-purpose surfactant according to claim 1, characterized in that, The silane coupling agent includes at least one of γ-aminopropyltriethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

7. The method for preparing the general-purpose surfactant according to claim 1, characterized in that, The catalyst includes at least one of dibutyltin dilaurate and dibutyltin acetate.

8. The method for preparing the general-purpose surfactant according to claim 1, characterized in that, The alcohol solvent includes at least one of ethanol, isopropanol, and methanol.

9. The method for preparing the general-purpose surfactant according to claim 1, characterized in that, The hydrocarbon solvent includes at least one of n-heptane and cyclohexane.

10. A general-purpose surfactant prepared by the preparation method according to any one of claims 1 to 9.

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