Water-dispersible organic silicon epoxy composite resin as well as preparation method and application thereof

Abstract

The invention discloses a water-dispersible organic silicon epoxy composite resin as well as a preparation method and application thereof. The composite resin comprises acrylic acid modified silicon resin, epoxy resin, a cosolvent, a wetting dispersant and deionized water; the preparation method comprises the following steps: preparing acrylic acid modified organic silicon resin from the composite resin through hydrosilylation, sequentially adding the epoxy resin, the cosolvent and the wetting dispersant, uniformly mixing, and gradually dripping deionized water in a heating state to obtain the acrylic acid modified organic silicon resin. The prepared composite resin has good dispersity; after being mixed with a water-based epoxy curing agent, the organic silicon resin can be applied to curing protection of a metal base material, in the coating drying process, due to polarity difference and density difference, the organic silicon resin easily floats on the surface of a coating to form a self-layering structure, and the surface of the cured coating has low surface energy and has hydrophobic and anti-corrosion characteristics; the flexible organic silicon resin has the characteristic of easy flowing in the coating, so that when the coating is damaged, the coating flows through deformation, and a self-repairing effect is formed.

Description

Technical Field

[0001] The present invention relates to a composite resin, in particular to a water-dispersible organosilicon-epoxy composite resin, and also to a preparation method and application of the water-dispersible organosilicon-epoxy composite resin. Background Art

[0002] Self-Stratifying Coatings is a functional coating with unique properties. Its most significant feature is that after construction, it can spontaneously form a multi-layer structure (such as a base layer, an intermediate layer, and a surface layer) through the physical or chemical action of the system's internal components without the need for external forces (such as mechanical stirring or manual stratification). This characteristic makes it significantly superior to traditional multi-layer coating systems in terms of performance and construction efficiency. It has multiple application scenarios, including: industrial anti-corrosion, architectural coatings, automotive and transportation, aerospace, and new energy fields. It mainly achieves this through formula design (such as density differences, surface tension differences, solubility differences, or chemical reaction rate differences between different components) so that the coating automatically layers during the drying and film-forming process.

[0003] However, the formulation design of such coatings is complex (requiring precise control of the stratification dynamics), some high-performance systems are costly, and their high sensitivity to the construction environment (such as temperature, humidity, and coating thickness) limits their large-scale application. Furthermore, due to the poor compatibility of the two polymer phases that make up self-stratifying coatings, the mechanical and corrosion resistance of the prepared paint films often fail to meet actual application requirements due to construction issues. Furthermore, the use of organic solvents can also pose environmental hazards; the development of environmentally friendly self-stratifying coatings with improved dispersion properties and stronger mechanical properties is urgently needed. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a water-dispersible organosilicon-epoxy composite resin with self-stratification and film-forming effect, hydrophobicity and corrosion resistance, and also to provide a preparation method and application of the above-mentioned water-dispersible organosilicon-epoxy composite resin.

[0005] Technical solution: The water-dispersible silicone epoxy composite resin of the present invention comprises the following components in percentage by weight:

[0006]

[0007] The acrylic modified silicone resin is prepared by hydrosilylation of a prepolymer mixture and a platinum water catalyst, and the preparation method comprises the following steps:

[0008] (1) Glycidyl methacrylate, hydrogenated silicone oil and vinyl silicone oil are uniformly mixed;

[0009] (2) adding platinum water catalyst, heating to 150°C to 180°C, and reacting for 10 minutes to 30 minutes;

[0010] (3) Cooling to 40-60°C, adding dipropylene glycol monomethyl ether, diluting, stirring for 10-20 minutes, and mixing evenly;

[0011] (4) adding triethanolamine and stirring the mixture at 40°C to 60°C for 2 to 5 hours to allow the triethanolamine to react with the epoxy groups in the system to undergo a ring-opening reaction;

[0012] (5) Hydrochloric acid is added dropwise to adjust the pH value of the system to 7-8, thereby obtaining acrylic acid-modified silicone resin.

[0013] The prepolymer mixture comprises glycidyl methacrylate, vinyl silicone oil, hydrogenated silicone oil, triethanolamine, hydrochloric acid and dipropylene glycol monomethyl ether in a mass ratio of 10 to 20:30 to 50:10 to 35:2 to 5:2 to 5:10 to 30; the mass of chloroplatinic acid in the platinum water catalyst is 20 ppm to 50 ppm of the mass of the prepolymer mixture.

[0014] The hydrogen content of the hydrogen-containing silicone oil is 1.5% to 1.65%, and the vinyl content of the vinyl silicone oil is 1.6% to 10%.

[0015] Wherein, the epoxy resin is a bisphenol F epoxy resin, and its epoxy value range is 0.44-0.54 mol / 100g.

[0016] Wherein, the wetting and dispersing agent is a nonionic reactive epoxy emulsifier or a nonionic surfactant; specifically, the brand produced by Solvay is Emulsifier, or Dow Triton TM X-405 nonionic surfactant.

[0017] Wherein, the cosolvent is one of ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether.

[0018] The preparation method of the above-mentioned water-dispersible silicone-epoxy composite resin is as follows: prepare an acrylic modified silicone resin by a hydrosilylation method, mix it with an epoxy resin, add a wetting dispersant and a cosolvent and mix evenly, then raise the system temperature to 60°C to 80°C, gradually add deionized water while stirring, and continue stirring for 2 hours to 6 hours after the addition is completed to obtain a water-dispersible silicone-epoxy composite resin.

[0019] The wetting and dispersing agent and the cosolvent are added and mixed, and the stirring condition is 1000 rpm to 2500 rpm for 30 minutes to 60 minutes; deionized water is gradually added dropwise while stirring, and the stirring speed is 1000 rpm to 3000 rpm, and the adding time is 1 hour to 4 hours.

[0020] The water-dispersible silicone epoxy composite resin can also be used in the curing and protection of metal substrates.

[0021] The water-dispersible silicone epoxy composite resin is evenly mixed with the water-based epoxy curing agent and then coated on a metal substrate such as a tinplate by spraying, rolling or the like for curing.

[0022] Principle of the invention: The water-dispersible silicone-epoxy composite resin of the present invention adopts a silicone structure modified by copolymerization of methyl methacrylate glycerol ether, which can effectively enhance its polarity and improve its compatibility with epoxy resin, so that during the curing process, it will not be affected by the poor mechanical and anti-corrosion properties of the coating caused by excessive polarity difference.

[0023] An acrylic-modified silicone resin was prepared through the aforementioned hydrosilylation reaction. This was then mixed with an epoxy resin and uniformly dispersed and stirred at high speed. A cosolvent and a wetting dispersant were then added, followed by further high-speed stirring to achieve uniform mixing. While the system was heated, deionized water was gradually added dropwise to obtain the designed water-dispersible silicone-epoxy composite resin.

[0024] After adding a water-based epoxy curing agent, the water-dispersible silicone-epoxy composite resin of the present invention can be dried and cured at room temperature. During the coating drying process, due to differences in polarity and density, the silicone resin tends to float on the coating surface, forming a self-stratified structure. The cured coating surface has a low surface energy, imparting hydrophobic and corrosion-resistant properties. Furthermore, the flexible silicone resin has easy flow properties within the coating, allowing it to deform and flow when damaged, creating a self-healing effect.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The water-dispersible silicone epoxy composite resin of the present invention has good water-dispersibility. Polymer resins of different polarities can be effectively and evenly dispersed in the aqueous phase system under the action of an emulsifier; after the composite resin forms a cured coating, it has strong mechanical properties and strong anti-corrosion properties. Due to the fluidity of the silicone oil, when the paint film is damaged, the silicone oil can be released from the coating to protect and self-repair the damaged area; (2) Its preparation method does not require high-temperature and high-pressure reactions, and the process is simple; using water as a solvent is safer and more environmentally friendly, and is easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the appearance of the water-dispersible organosilicon-epoxy composite resin prepared in Example 1;

[0027] Figure 2 The cross-sectional morphology of the cured coating of the water-dispersible organosilicon-epoxy composite resin prepared in the example was observed by scanning electron microscopy;

[0028] Figure 3is the contact angle of the cured coating of the water-dispersible organosilicon-epoxy composite resin prepared in Examples 1 to 4;

[0029] Figure 4 This is the self-healing experimental verification of the water-dispersible silicone epoxy composite resin of Example 1. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below with reference to the examples. The test materials used can be purchased through conventional channels.

[0031] Example 1

[0032] The water-dispersible silicone-epoxy composite resin of the present invention comprises the following components in percentage by weight:

[0033]

[0034] The acrylic modified silicone resin is prepared by a hydrosilylation process using a prepolymer mixture and a platinum water catalyst. The prepolymer mixture comprises the following components: 20 wt% glycidyl methacrylate, 30 wt% vinyl silicone oil, 10 wt% hydrogenated silicone oil, 5 wt% triethanolamine, 5 wt% hydrochloric acid (10% wt concentration), and 30 wt% dipropylene glycol monomethyl ether. The amount of chloroplatinic acid, an active ingredient of the platinum water catalyst, added is 20 ppm relative to the prepolymer. The preparation method comprises the following steps:

[0035] (1) Glycidyl methacrylate was mixed with hydrogenated silicone oil and vinyl silicone oil, and stirred at 500 rpm for 30 minutes to mix uniformly;

[0036] (2) Platinum water catalyst was added, the system temperature was raised to 150°C, and the reaction time was controlled within 30 minutes;

[0037] (3) The temperature was lowered to 40°C, and dipropylene glycol monomethyl ether was added to the system at a speed of 3000 rpm, and the mixture was diluted and stirred for 20 minutes to mix evenly;

[0038] (4) Adding triethanolamine in a designed proportion to the system, stirring and reacting at 40°C for 5 hours, triethanolamine reacts with the epoxy groups in the system to undergo a ring-opening reaction;

[0039] (5) Add hydrochloric acid (concentration 10% wt) dropwise in proportion to adjust the pH value of the system to the range of 7 to 8; and obtain an acrylic acid-modified silicone resin.

[0040] The epoxy resin is bisphenol F epoxy resin, and its epoxy value is 0.54 mol / 100 g. The wetting and dispersing agent is a brand produced by Solvay. Emulsifier. The cosolvent is ethylene glycol methyl ether. The raw materials for preparing acrylic modified silicone resin, wherein the hydrogen content of hydrogen-containing silicone oil is 1.65%, and the vinyl content of vinyl silicone oil is 1.6%.

[0041] The preparation method of the above-mentioned water-dispersible silicone-epoxy composite resin is as follows: first, an acrylic modified silicone resin is prepared by a hydrosilylation method, then the acrylic modified silicone resin is mixed with an epoxy resin, a wetting dispersant and a cosolvent are added, and the mixture is stirred at 1000 rpm for 60 minutes to mix evenly. Then, the system temperature is raised to 60°C, the stirring speed is increased to 1000 rpm, and deionized water is gradually added dropwise. The addition time is controlled to be 4 hours. After the addition is completed, the mixture is stirred at the same temperature and the same speed for 6 hours to prepare a water-dispersible silicone-epoxy composite resin by a phase inversion method.

[0042] like Figure 1 As shown in the figure, the physical appearance of the water-dispersible silicone-epoxy composite resin shows that it has good water-dispersibility. Under the action of the emulsifier, polymer resins of different polarities are effectively and evenly dispersed in the aqueous phase system.

[0043] Example 2

[0044] The water-dispersible silicone-epoxy composite resin of the present invention comprises the following components in percentage by weight:

[0045]

[0046] The acrylic modified silicone resin is prepared by hydrosilylation of a prepolymer mixture and a platinum water catalyst. The prepolymer mixture contains the following components: 18 wt% glycidyl methacrylate, 35 wt% vinyl silicone oil, 14 wt% hydrogenated silicone oil, 4 wt% triethanolamine, 4 wt% hydrochloric acid (10% wt concentration), and 25 wt% dipropylene glycol monomethyl ether. The amount of chloroplatinic acid, an active ingredient of the platinum water catalyst, added is 30 ppm relative to the prepolymer. The preparation method comprises the following steps:

[0047] (1) Glycidyl methacrylate was mixed with hydrogenated silicone oil and vinyl silicone oil, and stirred at 1000 rpm for 25 minutes to mix uniformly;

[0048] (2) Platinum water catalyst was added, the system temperature was raised to 160°C, and the reaction time was controlled within 20 minutes;

[0049] (3) The temperature was lowered to 45°C, and dipropylene glycol monomethyl ether was added to the system at a speed of 2800 rpm, and the mixture was diluted and stirred for 18 minutes to mix evenly;

[0050] (4) Adding triethanolamine in a designed proportion to the system, stirring and reacting at 45°C for 4 hours, triethanolamine reacts with the epoxy groups in the system to undergo a ring-opening reaction;

[0051] (5) Add hydrochloric acid (concentration 10% wt) dropwise in proportion to adjust the pH value of the system to the range of 7 to 8; and obtain an acrylic acid-modified silicone resin.

[0052] The epoxy resin is a bisphenol F epoxy resin with an epoxy value of 0.51 mol / 100 g. The wetting and dispersing agent is Triton from Dow Chemical. TM X-405 nonionic surfactant. The cosolvent is ethylene glycol butyl ether. The raw materials for preparing acrylic modified silicone resin include hydrogen content of 1.5% in hydrogen silicone oil and 4% in vinyl content in vinyl silicone oil.

[0053] The preparation method of the above-mentioned water-dispersible silicone-epoxy composite resin is as follows: first, an acrylic modified silicone resin is prepared by a hydrosilylation method, then the acrylic modified silicone resin is mixed with an epoxy resin, a wetting dispersant and a cosolvent are added, and the mixture is stirred at 1500 rpm for 50 minutes to mix evenly. Then, the system temperature is raised to 65°C, the stirring speed is increased to 1500 rpm, and deionized water is gradually added dropwise. The addition time is controlled to be 2 hours. After the addition is completed, the mixture is stirred at the same temperature and the same speed for 4 hours to prepare a water-dispersible silicone-epoxy composite resin by a phase inversion method.

[0054] Example 3

[0055] The water-dispersible silicone-epoxy composite resin of the present invention comprises the following components in percentage by weight:

[0056]

[0057] The acrylic modified silicone resin is prepared by a hydrosilylation process using a prepolymer mixture and a platinum water catalyst. The prepolymer mixture comprises the following components: 10 wt% glycidyl methacrylate, 50 wt% vinyl silicone oil, 26 wt% hydrogenated silicone oil, 2 wt% triethanolamine, 2 wt% hydrochloric acid (10% wt concentration), and 10 wt% dipropylene glycol monomethyl ether. The amount of chloroplatinic acid, an active ingredient of the platinum water catalyst, added is 40 ppm relative to the prepolymer. The preparation method comprises the following steps:

[0058] (1) Glycidyl methacrylate was mixed with hydrogenated silicone oil and vinyl silicone oil, and stirred at 1500 rpm for 15 minutes to mix uniformly;

[0059] (2) Platinum water catalyst was added, the system temperature was raised to 170°C, and the reaction time was controlled within 15 minutes;

[0060] (3) The temperature was lowered to 55°C, and dipropylene glycol monomethyl ether was added to the system at a rotation speed of 2200 rpm, and the mixture was diluted and stirred for 13 minutes to mix evenly.

[0061] (4) Adding triethanolamine in a designed proportion to the system, stirring and reacting at 50°C for 3 hours, triethanolamine reacts with the epoxy groups in the system to undergo a ring-opening reaction;

[0062] (5) Hydrochloric acid (concentration 10% wt) was added dropwise in proportion to adjust the pH value of the system to the range of 7 to 8 to obtain an acrylic acid-modified silicone resin.

[0063] The epoxy resin is a bisphenol F epoxy resin with an epoxy value of 0.51 mol / 100 g. The wetting and dispersing agent is a brand produced by Solvay. Emulsifier. The cosolvent is propylene glycol monomethyl ether. The vinyl content of the vinyl silicone oil is 8%.

[0064] The preparation method of the above-mentioned water-dispersible silicone-epoxy composite resin is as follows: first, an acrylic modified silicone resin is prepared by a hydrosilylation method, then the acrylic modified silicone resin is mixed with an epoxy resin, a wetting dispersant and a cosolvent are added, and the mixture is stirred at 2000 rpm for 40 minutes to mix evenly. Then, the system temperature is raised to 75°C, the stirring speed is increased to 2500 rpm, and deionized water is gradually added dropwise. The addition time is controlled to be 2 hours. After the addition is completed, the mixture is stirred at the same temperature and the same speed for 3 hours to prepare a water-dispersible silicone-epoxy composite resin by a phase inversion method.

[0065] Example 4

[0066] The water-dispersible silicone-epoxy composite resin of the present invention comprises the following components in percentage by weight:

[0067]

[0068] The acrylic modified silicone resin is prepared by a hydrosilylation process using a prepolymer mixture and a platinum water catalyst. The prepolymer mixture comprises the following components: 12 wt% glycidyl methacrylate, 35 wt% vinyl silicone oil, 35 wt% hydrogenated silicone oil, 3 wt% triethanolamine, 3 wt% hydrochloric acid (10% wt concentration), and 12 wt% dipropylene glycol monomethyl ether. The amount of chloroplatinic acid, an active ingredient of the platinum water catalyst, added is 50 ppm relative to the prepolymer. The preparation method comprises the following steps:

[0069] (1) Glycidyl methacrylate was mixed with hydrogenated silicone oil and vinyl silicone oil, and stirred at 2000 rpm for 10 minutes to mix uniformly;

[0070] (2) Platinum water catalyst was added, the system temperature was raised to 180°C, and the reaction time was controlled within 10 minutes;

[0071] (3) The temperature was lowered to 60°C, and dipropylene glycol monomethyl ether was added to the system at a speed of 2000 rpm, and the mixture was diluted and stirred for 10 minutes to mix evenly;

[0072] (4) Adding triethanolamine in a designed proportion to the system, stirring and reacting at 60°C for 2 hours, triethanolamine reacts with the epoxy groups in the system to undergo a ring-opening reaction;

[0073] (5) Add hydrochloric acid (concentration 10% wt) dropwise in proportion to adjust the pH value of the system to the range of 7 to 8; and obtain an acrylic acid-modified silicone resin.

[0074] The epoxy resin is a bisphenol F epoxy resin with an epoxy value of 0.44 mol / 100 g. The wetting and dispersing agent is Triton from Dow Chemical. TM X-405 nonionic surfactant. The cosolvent is dipropylene glycol monomethyl ether. The raw materials for preparing acrylic modified silicone resin include hydrogen silicone oil with a hydrogen content of 1.55% and vinyl silicone oil with a vinyl content of 10%.

[0075] The preparation method of the above-mentioned water-dispersible silicone-epoxy composite resin is as follows: first, an acrylic modified silicone resin is prepared by a hydrosilylation method, then the acrylic modified silicone resin is mixed with an epoxy resin, a wetting dispersant and a cosolvent are added, and the mixture is stirred at 2500 rpm for 30 minutes to mix evenly. Then, the system temperature is raised to 80°C, the stirring speed is increased to 3000 rpm, and deionized water is gradually added dropwise. The addition time is controlled to be 1 hour. After the addition is completed, the mixture is stirred at the same temperature and the same speed for 2 hours to prepare a water-dispersible silicone-epoxy composite resin by a phase inversion method.

[0076] The water-dispersible organosilicon epoxy composite resin prepared in Examples 1 to 4 was used for curing and coating the metal substrate: the water-dispersible organosilicon epoxy composite resin and the water-based epoxy curing agent (Dow DEH TM 805) After being evenly mixed in a mass ratio of 10:3, the mixture was sprayed on a metal substrate plate for curing, and the coating was allowed to stand at room temperature for 7 days to achieve curing.

[0077] Table 1 Mechanical properties of the cured coatings prepared from the water-dispersible organosilicon-epoxy composite resin of the present invention

[0078]

[0079] As shown in Table 1, which verifies the mechanical properties of the cured coating, it can be seen that the effective combination between the silicone resin and the epoxy resin gives the cured coating excellent mechanical properties.

[0080] like Figure 2Figure 2 shows the cured coating and cross-sectional morphology of the water-dispersible silicone-epoxy composite resin of Example 1. The figure indicates that since the silicone oil is chemically modified by glycidyl methacrylate, when it is blended with the epoxy resin, the phase separation trend of the two phases can be effectively suppressed. The silicone resin forms vesicle-like aggregates in the epoxy resin, forming a self-stratified morphology.

[0081] like Figure 3 As shown, the contact angles of the cured coatings prepared using the water-dispersible silicone-epoxy composite resins prepared in Examples 1 to 4 are all greater than 90°, indicating hydrophobicity. This is due to the low surface tension of the silicone oil in the coating.

[0082] like Figure 4 The left image shows the cured composite resin coating of Example 1 after cutting, showing obvious cracks. After the coating was left at room temperature for 60 hours, significant silicone resin coverage was observed in the gaps in the coating. This is due to the fluidity of the silicone oil, which releases from the coating when the paint film is damaged, protecting the damaged area.

Claims

1. A water-dispersible silicone epoxy composite resin, characterized in that: The composite resin comprises the following components in percentage by weight:

2. The water-dispersible silicone-epoxy composite resin according to claim 1, characterized in that: The acrylic modified silicone resin is prepared by hydrosilylation of a prepolymer mixture and a platinum water catalyst, and the preparation method comprises the following steps: (1) Glycidyl methacrylate, hydrogenated silicone oil and vinyl silicone oil are uniformly mixed; (2) adding platinum water catalyst, heating to 150°C to 180°C, and reacting for 10 minutes to 30 minutes; (3) Cooling to 40-60°C, adding dipropylene glycol monomethyl ether, diluting, stirring for 10-20 minutes, and mixing evenly; (4) adding triethanolamine and stirring the mixture at 40°C to 60°C for 2 to 5 hours to allow the triethanolamine to react with the epoxy groups in the system to undergo a ring-opening reaction; (5) Hydrochloric acid is added dropwise to adjust the pH value of the system to 7-8, thereby obtaining acrylic acid-modified silicone resin.

3. The water-dispersible silicone-epoxy composite resin according to claim 2, characterized in that: The prepolymer mixture comprises glycidyl methacrylate, vinyl silicone oil, hydrogenated silicone oil, triethanolamine, hydrochloric acid and dipropylene glycol monomethyl ether in a mass ratio of 10-20:30-50:10-35:2-5:2-5:10-30; the mass of chloroplatinic acid in the platinum water catalyst is 20ppm-50ppm of the mass of the prepolymer mixture.

4. The water-dispersible silicone-epoxy composite resin according to claim 2, wherein: The hydrogen content of the hydrogen-containing silicone oil is 1.5% to 1.65%, and the vinyl content of the vinyl silicone oil is 1.6% to 10%.

5. The water-dispersible silicone-epoxy composite resin according to claim 1, wherein The epoxy resin is a bisphenol F epoxy resin, and its epoxy value range is 0.44-0.54 mol / 100g.

6. The water-dispersible silicone-epoxy composite resin according to claim 1, wherein The wetting and dispersing agent is a nonionic reactive epoxy emulsifier or a nonionic surfactant.

7. The water-dispersible silicone-epoxy composite resin according to claim 1, wherein The cosolvent is one of ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol monomethyl ether and dipropylene glycol monomethyl ether.

8. A method for preparing the water-dispersible organosilicon-epoxy composite resin according to claim 1, characterized in that: The preparation method comprises the following steps: preparing an acrylic modified silicone resin by a hydrosilylation method, mixing the acrylic modified silicone resin with an epoxy resin, adding a wetting dispersant and a cosolvent, and mixing the mixture evenly; then raising the system temperature to 60° C. to 80° C., gradually adding deionized water dropwise while stirring, and continuing stirring for 2 to 6 hours after the addition is completed, thereby obtaining a water-dispersible silicone epoxy composite resin.

9. The preparation method according to claim 8, characterized in that Add the wetting dispersant and the cosolvent and mix them, stirring at 1000-2500 rpm for 30-60 minutes; gradually add deionized water dropwise while stirring, with the stirring speed at 1000-3000 rpm and the addition time at 1-4 hours.

10. Use of the water-dispersible organosilicon-epoxy composite resin according to claim 1 in curing and protecting metal substrates.

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