A high humidity environment primer and preparation method

Abstract

The present invention belongs to the field of fine chemical technology and specifically relates to a high-humidity environment primer and its preparation method. This primer not only rapidly penetrates, forming an integrated network structure between the treated surface and the penetrated interior, but also rapidly removes adsorbed moisture from the adhered surface under high humidity conditions, reducing the effect of moisture on adhesion. The polyalkoxysilane containing hydroxylamine groups in the primer further enhances the adhesion between the polyurethane urea sealant and the adherend. The high-humidity environment primer of the present invention can strengthen the bond between the polyurethane urea sealant or epoxy resin adhesive and the adherend in high-humidity environments with a relative humidity of 85% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemical industry, and particularly relates to a high-humidity environment primer and a preparation method thereof. Background Art

[0002] Polyurethane, polyurea and polyurethane urea are diverse in variety, have a wide range of raw material choices, and have excellent comprehensive performance. They are widely used as adhesives, potting compounds, sealants, etc. in many fields.

[0003] Traditional polyurethane primers are divided into one-component and two-component types. One-component primers are convenient to use, but their performance is inferior to that of two-component primers. Two-component polyurethane primers generally use isocyanate and polyether polyol to prepare a prepolymer, which is then cured with a diamine curing agent. The product has a large molecular weight and is difficult to penetrate into surface molecules like vulcanized rubber, resulting in little improvement in the adhesion of vulcanized rubber.

[0004] When bonding polyurethane urea sealants to various rubber surfaces, they have the disadvantage of weak adhesion to non-polar rubber. In this case, a layer of polyurethane or epoxy primer needs to be pre-coated on the rubber surface to enhance the adhesion between the polyurethane urea sealant and the rubber. This is especially true in the bonding and sealing of underwater facilities, in long-term dynamic vibration environments, and in the bonding and sealing of test pieces in long-term alternating temperature (low temperature) environments. These occasions require particularly high bonding strength, and commonly used polyurethane or epoxy primers can no longer meet the needs.

[0005] Polyurethane urea sealants are used in certain special environments, and the construction environment is harsh. For example, in the coastal areas of northern China, construction often needs to be carried out at low temperatures in winter, which is not friendly to epoxy primers that have high requirements for curing temperature. In summer, the high humidity environment will cause water vapor to accumulate on the rubber surface, which is also not friendly to polyurethane primers.

[0006] Therefore, there is a need for a polyurethane primer that can effectively remove water vapor that is easily accumulated on the rubber surface, easily penetrate into the rubber surface, and effectively increase the adhesion of polyurethane urea.

[0007] CN114381197A discloses a method for preparing a water vapor-resistant polyurethane primer. The primer comprises an isocyanate prepolymer, a silane coupling agent, and an alkane or cycloalkane solvent oil. The isocyanate prepolymer is prepared by polymerizing a polyisocyanate with a polyether polyol. This primer is primarily used for bonding various decorative panels to concrete surfaces and significantly reduces the foaming problem caused by the reaction of isocyanate with water on wet composite panels.

[0008] CN12675584B discloses a polyurethane primer for spraying polyurea concrete surfaces, its preparation method, and its application. The system is a two-component system: Component A is an isocyanate prepolymer prepared by polymerizing PAPI and a polyether polyol, and Component B is an amino chain extender, preferably MOCA. Because the polyether polyol used in this primer has a high molecular weight after curing, it provides excellent pore-blocking properties when applied to concrete surfaces. Furthermore, the direct curing using an ammonia-based curing agent offers the advantage of rapid curing.

[0009] CN103820017A discloses an epoxy-modified polyurethane primer and its preparation method. The system is a two-component system: Component A is an isocyanate prepolymer prepared by polymerizing polyisocyanates and polyether polyols, and Component B is a mixture of an amino curing agent and a hydroxyl curing agent. Because the polyether polyol used in this primer has a high molecular weight after curing, it offers excellent pore-blocking properties and strong adhesion when applied to concrete surfaces. Summary of the Invention

[0010] The present invention mainly provides an antioxidant based on lignin, having more phenolic hydroxyl groups and better compatibility with polyurethane, and a method for preparing the antioxidant. The technical solution is as follows:

[0011] A high-humidity environment primer comprises a component A and a component B in a mass ratio of (2-3):1; in parts by mass, the component A comprises 90-100 parts of a polyisocyanate oligomer and 0.1-0.5 parts of a catalyst; the component B comprises 10-30 parts of a polyalkoxysilane, 10-20 parts of a latent curing agent and 10-20 parts of a solvent; the polyalkoxysilane self-polymerizes under the action of divalent cations; the divalent cations comprise one or more of calcium ions, copper ions, zinc ions, strontium ions, barium ions, cobalt ions, nickel ions and manganese ions.

[0012] Furthermore, the polyisocyanate oligomer is one or more of polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate trimer, hexamethylene diisocyanate dimer, hexamethylene diisocyanate biuret, toluene diisocyanate dimer, toluene diisocyanate trimer, and toluene diisocyanate-trimethylolpropane adduct; the catalyst is one or both of dibutyltin dilaurate and stannous octoate; the latent curing agent is one or more of oxazolidine, ketimine, or aldimine latent curing agents; and the solvent is one or both of butanone and ethyl acetate.

[0013] A method for preparing the above-mentioned high-humidity environment primer comprises the following steps:

[0014] a. Preparation of a polyalkoxysilane containing a hydroxylamine group using γ-aminopropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane;

[0015] b. hydroformylating a polyalkoxysilane containing a hydroxylamine group to obtain a reaction solution containing a hydroformylated polyalkoxysilane;

[0016] c. rapidly placing sodium oxybate in a reaction solution containing a aldehyde-containing polyalkoxysilane to react and obtain a polyalkoxysilane;

[0017] d. Mixing the polyisocyanate oligomer and the catalyst according to the formula to obtain component A; mixing the polyalkoxysilane, the latent curing agent and the solvent according to the formula to obtain component B;

[0018] e. Mix component A and component B evenly.

[0019] Furthermore, the preparation of the polyalkoxysilane containing a hydroxylamine group in step a includes the following steps: at 50° C., taking γ-aminopropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane in a substance ratio of 1:2, respectively, and adding γ-glycidyloxypropyltrimethoxysilane to γ-aminopropyltriethoxysilane at a rate of 2 to 6 mL / min while stirring. After the addition, continue stirring and reacting for 4 to 8 hours, and then let it stand for 42 to 54 hours to obtain a reaction solution of the polyalkoxysilane containing a hydroxylamine group.

[0020] Furthermore, the hydroformylation in step b includes the following steps: preparing a saturated solution of sodium periodate, adding the saturated sodium periodate solution to the polyalkoxysilane reaction solution containing a hydroxylamine group obtained in step a, reacting for 1 to 2 hours at room temperature in the dark, placing it in a refrigerated environment and quickly cooling it to 0 to 2° C. to obtain a reaction solution containing hydroformylated polyalkoxysilane.

[0021] Furthermore, the molar ratio of the sodium periodate in step b to the γ-aminopropyltriethoxysilane in step a is (2-2.5):1.

[0022] Furthermore, the preparation of the polyalkoxysilane in step c comprises the following steps:

[0023] Prepare a 1-1.2 mol / L sodium oxybate ethanol solution, then add the sodium oxybate ethanol solution dropwise to the reaction solution containing the aldehyded polyalkoxysilane at a rate of 2-6 mL / min, add hydrogen peroxide solution, and then heat to 80-90° C. and react for 16-20 hours to obtain the product.

[0024] Furthermore, the molar ratio of the sodium oxybate to the γ-aminopropyltriethoxysilane in step a is (2-2.5):1; the molar ratio of the hydrogen peroxide to the sodium oxybate is 1:(1-1.2).

[0025] The high humidity environment primer is used in the bonding of polyurethane sealant and weak polar materials, and the relative humidity of the high humidity environment is above 85%.

[0026] Furthermore, the weak polar material includes one of styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, butyl rubber or glass fiber reinforced plastic.

[0027] By adopting the above scheme, the method of the present invention has the following advantages:

[0028] 1. Using the primer of the present invention to perform surface treatment on non-polar materials can significantly improve the interfacial bonding strength, so that the test piece can adapt to the use in the alternating fatigue environment and improve the durability, which is particularly suitable for use in harsh environments.

[0029] 2. The primer of the present invention adopts isocyanate oligomer, which has the ability of rapid penetration compared with the traditional isocyanate prepolymer primer. Under high humidity conditions, the present invention can significantly improve the interfacial bonding strength between polyurethane urea sealant and rubber, and is particularly suitable for the filling construction of large-scale mobile polyurethane sealants (such as shipbuilding industry).

[0030] 3. After the polyalkoxysilane coupling agent of the present invention is added to the system, due to the large number of alkoxy groups on a single molecule, it can react with the surface of fillers in the adherend material, such as reinforcing carbon black, to form cross-linking points in the system, thereby playing a reinforcing role.

[0031] 4. The polyalkoxysilane coupling agent of the present invention undergoes self-crosslinking under the action of water vapor in the environment, generating polysiloxane chains with a spatial structure, which coat and entangle the reinforcing fillers and molecular chains in the adhered material, thereby improving the bonding strength with the adhered material.

[0032] 5. In practical applications, the sodium ions in the polyalkoxysilane in the primer of the present invention that can be in contact with the outside world are easily replaced by divalent metal ions in the environment and form cross-linking nodes, which further cross-links itself and makes the structure tighter, further preventing the entry of water vapor on the surface and eliminating the negative impact of water vapor on adhesion.

[0033] 6. The polyalkoxysilane and latent curing agent in the primer of the present invention have a synergistic effect. Using polyalkoxysilane or latent curing agent alone has limited improvement on the mechanical properties of the treated material, but using both simultaneously can significantly improve the mechanical strength of the material.

[0034] 7. The primer of the present invention has a fast reaction speed and can achieve a rapid increase in bonding strength in a few minutes, and is highly practical. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Example 1:

[0037] Weigh the following weights of raw materials of component A: 100 g of hexamethylene diisocyanate trimer and 0.5 g of dibutyltin dilaurate, and mix the above components evenly to obtain component A of the primer.

[0038] Weigh the following weights of the raw materials of component B: 20 ​​g TP-830 oxazolidine latent curing agent, 15 g polyalkoxysilane, and 15 g butanone solution, and mix the above components evenly to obtain component B of the primer.

[0039] Mix components A and B in a ratio of 2:1 to obtain the primer.

[0040] Example 2:

[0041] Weigh the following weights of raw materials of component A: 100 g of toluene diisocyanate trimer and 0.5 g of dibutyltin dilaurate, and mix the above components evenly to obtain component A of the primer.

[0042] Weigh the following weights of the raw materials of component B: 20 ​​g of DT-134 ketimine latent curing agent, 15 g of polyalkoxysilane, and 15 g of ethyl acetate solution, and mix the above components evenly to obtain component B of the primer.

[0043] Mix components A and B in a ratio of 2:1 to obtain the primer.

[0044] Comparative Example 1:

[0045] Weigh the following weights of raw materials of component A: 100 g of toluene diisocyanate trimer and 0.5 g of dibutyltin dilaurate, and mix the above components evenly to obtain component A of the primer.

[0046] Weigh the following weights of the raw materials of component B: 30 g of DT-134 ketimine latent curing agent and 20 g of ethyl acetate solution, and mix the above components evenly to obtain component B of the primer.

[0047] Mix components A and B in a ratio of 2:1 to obtain the primer.

[0048] Comparative Example 2:

[0049] Weigh the following weights of raw materials of component A: 100 g of toluene diisocyanate trimer and 0.5 g of dibutyltin dilaurate, and mix the above components evenly to obtain component A of the primer.

[0050] Weigh the following weights of the raw materials of component B: dissolve 20 g of di-o-chlorodiphenylamine curing agent in 30 g of ethyl acetate solution to obtain component B of the primer.

[0051] Mix components A and B in a ratio of 2:1 to obtain the primer.

[0052] Comparative Example 3:

[0053] Weigh the following weights of raw materials of component A: 100 g of hexamethylene diisocyanate trimer and 0.5 g of dibutyltin dilaurate, and mix the above components evenly to obtain component A of the primer.

[0054] Weigh the following weights of the raw materials of component B: 30 g of polyalkoxysilane and 25 g of ethyl acetate solution, and mix the above components evenly to obtain component B of the primer.

[0055] Mix components A and B in a ratio of 2:1 to obtain the primer.

[0056] Comparative Example 4:

[0057] Weigh the following weights of raw materials of component A: 100 g of hexamethylene diisocyanate trimer and 0.5 g of dibutyltin dilaurate, and mix the above components evenly to obtain component A of the primer.

[0058] Weigh the following weights of the raw materials of component B: 20 ​​g of TP-830 oxazolidine latent curing agent, 15 g of γ-glycidyloxypropyltrimethoxysilane, and 15 g of butanone solution, and mix the above components evenly to obtain component B of the primer.

[0059] Mix components A and B in a ratio of 2:1 to obtain the primer.

[0060] Example sample test:

[0061] (1) Clean the surface of the treated material: wipe the surface with acetone solution to remove dirt;

[0062] (2) Post-treatment placement: The primer of each embodiment and comparative example was sprayed onto the surface of the treated material to complete the surface treatment. After standing for 0.5 hours to 7 days, a polyurethane urea system sealant was used for bonding. The physical strength of the surface-treated styrene-butadiene rubber and untreated styrene-butadiene rubber of each embodiment and comparative example, as well as the treated fiberglass, was tested according to the above steps. The test results of Examples 1-2 and the sample without primer at 23°C and 90% humidity with styrene-butadiene rubber as the treated material are shown in Table 1 below:

[0063] Table 1:

[0064]

[0065] After the primer coating of Example 1 is applied, it can significantly improve the shear strength and peel strength of the styrene-butadiene rubber after standing for 0.5 hours, and the data after standing for 0.5 and 7 days do not change much, indicating that the primer can fully react in just 0.5 hours and achieve the target performance, with high efficiency and strong practicality. In addition, the improvement of the mechanical properties of the styrene-butadiene rubber in Examples 1 and 2 is significantly higher than that in the control example without primer coating, and the improvement is doubled, indicating that the primer of the present invention can not only increase the viscosity of the sealant, but also improve the physical and mechanical properties of the treated material.

[0066] At 23° C. and 90% humidity, the properties of the primers of Example 1 and Comparative Examples 1 to 4 were tested using styrene-butadiene rubber as the treated material. The results are shown in Table 2 below:

[0067] Table 2:

[0068]

[0069] As shown in Table 2, compared to Example 1, the shear and peel strengths of the materials in Comparative Examples 1 and 2, which lack polyalkoxysilane, and Comparative Example 3, which lacks a latent curing agent, are significantly reduced, indicating that the use of polyalkoxysilane or latent curing agent alone has limited effect on improving the mechanical properties of the materials. Furthermore, Comparative Example 4, which utilizes untreated conventional alkoxysilane, improves the mechanical properties of styrene-butadiene rubber only slightly more than Comparative Examples 1 and 2, which lack polyalkoxysilane, demonstrating a significant difference compared to Example 1. This suggests that the polyalkoxysilane of the present invention and the latent curing agent exhibit a synergistic effect compared to conventional alkoxysilanes.

[0070] At 23°C and 90% humidity, the performance of the primers of Example 1 and Comparative Example 1 was tested using glass fiber reinforced plastic as the treated material. The results are shown in Table 3 below:

[0071] Table 3:

[0072] Example 1 Comparative Example 1 Placement time after treatment 0.5h 0.5h Shear strength MPa 10.5 5.4

[0073] The primer of Example 1 has an effect of improving the shear strength of FRP that is nearly twice as strong as that of Comparative Example 1 in which no polyalkoxysilane is used, indicating that the primer of the present invention can be applied to materials of various properties.

[0074] At 23°C and different humidity conditions, the performance of the primer of Example 1 was tested using styrene-butadiene rubber as the treated material. The results are shown in Table 4 below:

[0075] Table 4:

[0076] Example 1 Example 1 Example 1 Example 1 relative humidity 90％ 50％ 75％ 95％ Placement time after treatment 0.5h 0.5h 0.5 0.5h Shear strength MPa 5.3 5.2 5.5 5.1 Peel strength kN / m 8.8 8.8 8.7 8.6

[0077] As can be seen from Table 4, the primer of the present invention can react and work normally in a humidity environment of 50-95%, and the effect of improving the mechanical properties of styrene-butadiene rubber remains at the same level, indicating that the primer of the present invention can adapt to a wide range of humidity environments, has low humidity requirements, and is extremely widely used.

[0078] Those skilled in the art can make various other corresponding changes and deformations based on the technical solutions and concepts described above, and all of these changes and deformations should fall within the scope of protection of the claims of the present invention.

Claims

1. A high humidity environment primer, characterized in that: The invention comprises a component A and a component B in a mass ratio of (2-3):1; in parts by mass, the component A comprises 90-100 parts of a polyisocyanate oligomer and 0.1-0.5 parts of a catalyst; the component B comprises 10-30 parts of a polyalkoxysilane, 10-20 parts of a latent curing agent, and 10-20 parts of a solvent; the polyalkoxysilane self-polymerizes under the action of divalent cations; the divalent cations comprise one or more of calcium ions, copper ions, zinc ions, strontium ions, barium ions, cobalt ions, nickel ions, and manganese ions; and the preparation of the polyalkoxysilane comprises the following steps: a. At 50°C, add γ-aminopropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane in a 1:2 molar ratio. While stirring, add γ-glycidyloxypropyltrimethoxysilane to γ-aminopropyltriethoxysilane at a rate of 2-6 mL / min. Continue stirring after addition for 4-8 hours, then allow the mixture to stand for 42-54 hours to obtain a reaction solution of a polyalkoxysilane containing a hydroxylamine group. b. Prepare a saturated solution of sodium periodate and add the saturated sodium periodate solution to the reaction solution of the polyalkoxysilane containing hydroxylamine groups obtained in step a. Allow to react at room temperature in the dark for 1-2 hours. Then, refrigerate and quickly cool to 0-2°C to obtain a reaction solution containing the formaldehyded polyalkoxysilane. c. Prepare a 1-1.2 mol / L sodium oxybate ethanol solution, then add the sodium oxybate ethanol solution dropwise to the reaction solution containing the aldehyded polyalkoxysilane at a rate of 2-6 mL / min. Add hydrogen peroxide solution, and then raise the temperature to 80-90°C and react for 16-20 hours to obtain the polyalkoxysilane.

2. The high humidity environment primer according to claim 1, characterized in that: The polyisocyanate oligomer is one or more of polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate trimer, hexamethylene diisocyanate dimer, hexamethylene diisocyanate biuret, toluene diisocyanate dimer, toluene diisocyanate trimer, and toluene diisocyanate-trimethylolpropane adduct; the catalyst is one or both of dibutyltin dilaurate and stannous octoate; the latent curing agent is one or more of oxazolidine, ketimines, or aldimines; and the solvent is one or both of butanone and ethyl acetate.

3. The high humidity environment primer according to claim 1, characterized in that The molar ratio of the sodium periodate in step b to the γ-aminopropyltriethoxysilane in step a is (2-2.5):

1.

4. The high humidity environment primer according to claim 1, characterized in that The molar ratio of the sodium oxybate to the γ-aminopropyltriethoxysilane in step a is (2-2.5):1; the molar ratio of the hydrogen peroxide to the sodium oxybate is 1:(1-1.2).

5. A method for preparing a high-humidity environment primer according to any one of claims 1 to 2, characterized in that: The following steps are involved: Preparation of polyalkoxysilane containing hydroxylamine groups using γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; hydroformylating a polyalkoxysilane containing a hydroxylamine group to obtain a reaction solution containing the hydroformylated polyalkoxysilane; Rapidly placing sodium oxybate in a reaction solution containing aldehyde-containing polyalkoxysilane to react and obtain polyalkoxysilane; Mixing a polyisocyanate oligomer and a catalyst according to the formula amount to obtain component A; mixing a polyalkoxysilane, a latent curing agent and a solvent according to the formula amount to obtain component B; Mix component A and component B evenly.

6. Use of the high-humidity environment primer according to claim 1 in bonding polyurethane sealants to weakly polar materials, characterized in that: The relative humidity of the high humidity environment used is above 50%.

7. The use according to claim 6, characterized in that The weakly polar material includes one of styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, butyl rubber or glass fiber reinforced plastic.

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