Preparation method of UV-moisture multiple curing polyurethane modified acrylate three-protection paint

Abstract

The application relates to the polyurethane technical field and discloses a preparation method of UV-humidity multi-curing polyurethane modified acrylate three-protection paint. 100 parts by weight of polyurethane modified acrylate, 12-18 parts by weight of tertiary amine diacrylate diluent, 0.5-1 parts by weight of thickening agent and 3.3-3.8 parts by weight of photoinitiator are mixed to obtain the UV-humidity multi-curing polyurethane modified acrylate three-protection paint. The terminal of the polyurethane modified acrylate is introduced with active chlorine atoms, can be subjected to quaternization reaction with the tertiary amine groups of the tertiary amine diacrylate diluent, thereby introducing the antibacterial quaternary ammonium salt groups, and the polyurethane paint is endowed with excellent antibacterial and bactericidal properties. The polyurethane modified acrylate simultaneously exists in the wet curing, light curing crosslinking and hydrogen bond crosslinking and other multiple crosslinking actions, so that the polyurethane adhesive film shows higher tensile strength and elongation at break. And the polyurethane adhesive film has good water resistance and salt fog resistance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of polyurethane, in particular to a preparation method of UV-humidity multi-curing polyurethane modified acrylate three-protection paint. BACKGROUND

[0002] The polyurethane modified acrylate contains light-curable alkenyl groups, and can be used to prepare light-cured paint coatings, adhesives and other products, and has wide application in PCB circuit boards, electronics and electrical appliances, building materials, mechanical equipment and the like. The active diluent of the light-cured polyurethane modified acrylate mainly includes dipropylene glycol diacrylate, tripropylene glycol diacrylate and trimethylolpropane triacrylate.

[0003] Isocyanate and siloxane groups are introduced into the molecular chain of the polyurethane modified acrylate, and the molecular chain is crosslinked at room temperature by reacting with water in the air, so that the crosslinking density of the molecular chain is improved, and good wet curing performance is obtained. The Chinese patent with the publication number CN117925153B discloses a high-adhesion UV-humidity dual-curing three-protection paint and a preparation method thereof. The three-protection paint is prepared by using a triazine-containing nitrogen heterocyclic organic compound containing three isocyanate groups, a hydroxyl-containing acrylate derivative, a double-end hydroxyl hydrogenated polybutadiene, an active diluent and a free radical type photoinitiator as raw materials. The prepared dual-curing three-protection paint has the advantages of high adhesion, good salt mist resistance and high flexibility. However, the three-protection paint does not have good antibacterial performance, which limits its practical application in antibacterial and mildew-proof aspects. SUMMARY

[0004] (I) The technical problem solved by the present application is to provide a UV-humidity multi-curing polyurethane modified acrylate three-protection paint with good mechanical properties and excellent antibacterial and mildew-proof performance.

[0005] (II) The technical solution is a preparation method of a UV-humidity multi-curing polyurethane modified acrylate three-protection paint, which comprises the following steps.

[0006] Step A: In a nitrogen atmosphere, vacuum-dried polyether polyol, diisocyanate, 3-chloro-2-hydroxypropyl methacrylate and N,N-dimethylformamide are added to a reaction container, and then dibutyltin dilaurate is added dropwise after stirring. The mixture is heated to 85-95 DEG C and reacted for 1.5-3 hours. After cooling, a polyurethane modified acrylate is obtained.

[0007] Step B: 100 parts by weight of the polyurethane modified acrylate, 12-18 parts by weight of a tertiary amine diacrylate diluent, 0.8-1.4 parts by weight of a defoaming agent, 0.6-1 part by weight of a leveling agent and 0.5-1 part by weight of a thickening agent are added to a container and stirred uniformly. Then, 3.3-3.8 parts by weight of a photoinitiator is added to obtain a UV-humidity multi-curing polyurethane modified acrylate three-protection paint.

[0008] Preferably, the molar ratio of the polyether polyol, the diisocyanate, and the 3-chloro-2-hydroxypropyl methacrylate is 1:(1.3-1.36):(0.28-0.35).

[0009] Preferably, the temperature of the reaction in step A.

[0010] Preferably, the polyether polyol is polyethylene glycol, polypropylene glycol, or polytetrahydrofuran ether glycol.

[0011] Preferably, the diisocyanate is isophorone diisocyanate or toluene-2,4-diisocyanate.

[0012] Preferably, the photoinitiator is photoinitiator 1173 or photoinitiator 184.

[0013] Preferably, the preparation method of the tertiary amine diacrylate diluent comprises:

[0014] (1) adding a solvent, isocyanatoethyl methacrylate, N-methyldiethanolamine, and triethylamine in a molar ratio of (2.8-3.6):1:(0.2-0.26) into a reaction container, reacting at 20-50°C for 6-12h, removing the solvent by rotary evaporation, and separating by silica gel column chromatography to obtain the tertiary amine diacrylate diluent.

[0015]

[0016] Preferably, the solvent in (1) is dichloromethane or tetrahydrofuran.

[0017] (III) Technical effects: The present application uses 3-chloro-2-hydroxypropyl methacrylate to cap the generated terminal isocyanate prepolymer, and by adjusting the reaction ratio of the polyether polyol, the diisocyanate monomer, and the 3-chloro-2-hydroxypropyl methacrylate, the alkene group for light curing polymerization and the isocyanate group for wet curing are introduced at both ends of the polyurethane, respectively, which endows the polyurethane modified acrylate with good light curing and wet curing properties.

[0018] The present application introduces active chlorine atoms at the end of the polyurethane modified acrylate, which can undergo quaternization reaction with the tertiary amine group of the tertiary amine diacrylate diluent during the curing process, thereby introducing the antibacterial quaternary ammonium salt group into the molecular chain of the polyurethane modified acrylate, which endows the polyurethane paint with excellent antibacterial and bactericidal properties.

[0019] The tertiary amine diacrylate diluent of the present application contains urethane groups, which can form hydrogen bond crosslinking with urethane groups in the polyurethane molecular chain, so that the polyurethane modified acrylate simultaneously has multiple crosslinking effects of moisture curing, light curing crosslinking, hydrogen bond crosslinking, etc., the crosslinking degree between molecular chains is improved, and the polyurethane film shows higher tensile strength and elongation at break. And it has good water resistance and salt fog resistance. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present application, the present application will be described in more detail below. However, it should be understood that the present application can be realized in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the disclosure of the present application more thorough and comprehensive.

[0021] Example 1:

[0022] (1) Add 500 mL of dichloromethane, 68 mmol of isocyanatoethyl methacrylate, 20 mmol of N-methyldiethanolamine, 5.2 mmol of triethylamine to a reaction container, react at 30°C for 8 h, remove the solvent by rotary evaporation, and separate by silica gel column chromatography to obtain the tertiary amine diacrylate diluent.

[0023] (2) Under a nitrogen atmosphere, add 100 mmol of vacuum-dried and dehydrated polytetrahydrofuran ether glycol 1000, 136 mmol of toluene-2,4-diisocyanate, 28 mmol of 3-chloro-2-hydroxypropyl methacrylate, 15 mL of N,N-dimethylformamide to a reaction container, add 0.17 g of dibutyltin dilaurate after stirring, heat to 85°C, react for 3 h, and cool to obtain the polyurethane modified acrylate.

[0024] (3) Add 1000 g of the polyurethane modified acrylate, 120 g of the tertiary amine diacrylate diluent, 8 g of the defoaming agent Lenco 2192, 10 g of the leveling agent TEGO 4100, and 7 g of the thickening agent TT-935 to a container, stir and mix uniformly, and add 33 g of the photoinitiator 1173 to obtain the UV-humidity multi-curing polyurethane modified acrylate three-protection paint.

[0025] Comparative Example 1: The difference between this comparative example and Example 1 is that hydroxyethyl methacrylate is used instead of 3-chloro-2-hydroxypropyl methacrylate.

[0026] (1) Into a reaction vessel was added 100 mmol of vacuum dried dehydrated polytetramethylene ether glycol 1000, 136 mmol of toluene-2,4-diisocyanate, 28 mmol of hydroxyethyl methacrylate, 15 mL of N,N-dimethylformamide, after stirring, 0.17 g of dibutyltin dilaurate was added dropwise, heated to 85°C, reacted for 3 h, and cooled to obtain a urethane-modified acrylate.

[0027] (2) Into a vessel was added 1000 g of the urethane-modified acrylate, 120 g of the tertiary amine diacrylate diluent, 8 g of the defoamer Lencol o 2192, 10 g of the leveling agent TEGO 4100, 7 g of the thickener TT-935, stirred and mixed uniformly, and 33 g of the photoinitiator 1173 was added to obtain a UV-humidity multi-curing urethane-modified acrylate three-antifouling paint.

[0028] Comparative Example 2: The difference between this comparative example and Example 1 is that the dipropylene glycol diacrylate was used as the diluent instead of the tertiary amine diacrylate diluent.

[0029] (1) Into a reaction vessel was added 100 mmol of vacuum dried dehydrated polytetramethylene ether glycol 1000, 136 mmol of toluene-2,4-diisocyanate, 28 mmol of 3-chloro-2-hydroxypropyl methacrylate, 15 mL of N,N-dimethylformamide, after stirring, 0.17 g of dibutyltin dilaurate was added dropwise, heated to 85°C, reacted for 3 h, and cooled to obtain a urethane-modified acrylate.

[0030] (2) Into a vessel was added 1000 g of the urethane-modified acrylate, 120 g of the dipropylene glycol diacrylate diluent, 8 g of the defoamer Lencol o 2192, 10 g of the leveling agent TEGO 4100, 7 g of the thickener TT-935, stirred and mixed uniformly, and 33 g of the photoinitiator 1173 was added to obtain a UV-humidity multi-curing urethane-modified acrylate three-antifouling paint.

[0031] Comparative Example 3: The difference between this comparative example and Example 1 is that 2-acrylic acid-1,1'-[(methylamino)di-2,1-ethanediyl] ester (CAS No. 18507-41-0, structural formula ) was used instead of the tertiary amine diacrylate diluent.

[0032] (1) Into a reaction vessel, 100 mmol of vacuum-dried dehydrated polytetrahydrofuran ether glycol 1000, 136 mmol of toluene-2,4-diisocyanate, 28 mmol of 3-chloro-2-hydroxypropyl methacrylate, 15 mL of N,N-dimethylformamide were added, 0.17 g of dibutyltin dilaurate was added dropwise after stirring, heated to 85°C, reacted for 3 h, cooled, to obtain a polyurethane-modified acrylate.

[0033] (2) Into a container, 1000 g of polyurethane-modified acrylate, 120 g of 2-acrylic acid-1,1'-[(methylamino)di-2,1-ethanediyl] ester, 8 g of antifoaming agent Lencol o 2192, 10 g of leveling agent TEGO4100, 7 g of thickening agent TT-935 were added and stirred uniformly, 33 g of photoinitiator 1173 was added to obtain a UV-humidity multi-curing polyurethane-modified acrylate three-protection paint.

[0034] Example 2:

[0035] (1) Into a reaction vessel, 600 mL of tetrahydrofuran, 72 mmol of isocyanatoethyl methacrylate, 20 mmol of N-methyldiethanolamine, 5.2 mmol of triethylamine were added and reacted at 50°C for 6 h, the solvent was removed by rotary evaporation, and the tertiary amine diacrylate diluent was separated by silica gel column chromatography.

[0036] (2) Into a reaction vessel, 100 mmol of vacuum-dried dehydrated polyethylene glycol 1000, 133 mmol of isophorone diisocyanate, 32 mmol of 3-chloro-2-hydroxypropyl methacrylate, 15 mL of N,N-dimethylformamide were added, 0.18 g of dibutyltin dilaurate was added dropwise after stirring, heated to 95°C, reacted for 1.5 h, cooled, to obtain a polyurethane-modified acrylate.

[0037] (3) Into a container, 1000 g of polyurethane-modified acrylate, 140 g of tertiary amine diacrylate diluent, 8 g of antifoaming agent Lencol o 2192, 10 g of leveling agent TEGO4100, 5 g of thickening agent TT-935 were added and stirred uniformly, 33 g of photoinitiator 184 was added to obtain a UV-humidity multi-curing polyurethane-modified acrylate three-protection paint.

[0038] Example 3:

[0039] (1) Into a reaction vessel, 500 mL of dichloromethane, 56 mmol of isocyanatoethyl methacrylate, 20 mmol of N-methyldiethanolamine, 4 mmol of triethylamine were added and reacted at 20°C for 12 h, the solvent was removed by rotary evaporation, and the tertiary amine diacrylate diluent was separated by silica gel column chromatography.

[0040] (2) Into a reaction vessel were added 100 mmol of vacuum-dried dehydrated polytetramethylene ether glycol 1000, 130 mmol of isophorone diisocyanate, 35 mmol of 3-chloro-2-hydroxypropyl methacrylate, 20 mL of N,N-dimethylformamide, after stirring, 0.18 g of dibutyltin dilaurate was added dropwise, heated to 90°C, reacted for 2 h, and cooled to obtain a polyurethane-modified acrylate.

[0041] (3) Into a container were added 1000 g of the polyurethane-modified acrylate, 160 g of a tertiary amine diacrylate diluent, 14 g of an antifoaming agent Lenco 2192, 6 g of a leveling agent TEGO 4100, and 8 g of a thickening agent TT-935, which were stirred and uniformly mixed, and 38 g of a photoinitiator 1173 was added to obtain a UV-humidity multi-curing polyurethane-modified acrylate three-protection paint.

[0042] Example 4:

[0043] (1) Into a reaction vessel were added 100 mmol of vacuum-dried dehydrated polytetramethylene ether glycol 1000, 130 mmol of isophorone diisocyanate, 35 mmol of 3-chloro-2-hydroxypropyl methacrylate, 20 mL of N,N-dimethylformamide, after stirring, 0.18 g of dibutyltin dilaurate was added dropwise, heated to 90°C, reacted for 2 h, and cooled to obtain a polyurethane-modified acrylate.

[0044] (2) Into a container were added 1000 g of the polyurethane-modified acrylate, 180 g of a tertiary amine diacrylate diluent (prepared according to the method of Example 1), 12 g of an antifoaming agent Lenco 2192, 6 g of a leveling agent TEGO 4100, and 10 g of a thickening agent TT-935, which were stirred and uniformly mixed, and 38 g of a photoinitiator 1173 was added to obtain a UV-humidity multi-curing polyurethane-modified acrylate three-protection paint.

[0045] The polyurethane-modified acrylate three-protection paint was poured into a substrate, and first light-cured in a UV light-curing machine that had been preheated for 20 s, the main wavelength of the light-curing machine was 365 nm, and the light intensity was 800 mW / cm 2 . Then, the wet curing was performed at 25°C for 7 days, and the relative humidity was 60%.

[0046] The tensile properties of the cured film were tested according to the GB / T 1040.1-2018 standard.

[0047] The salt spray resistance of the paint film was tested according to the GB / T 1771-2007 standard. The water washing resistance was tested according to the GB / T 1733-1993 standard. The substrate was tinplate.

[0048] The antibacterial performance of the paint film was tested according to GB / T 21866-2008 standard. The test bacteria were Escherichia coli and Staphylococcus aureus. The antibacterial rate R = (B-C) / B x 100%.

[0049] B is the average number of recovered bacteria (cfu / piece) after 24 hours of the blank control sample, with the paint film of Comparative Example 1 as the blank control sample.

[0050] C is the average number of recovered bacteria (cfu / piece) after 24 hours of the antibacterial sample.

[0051] Table 1 Performance test of polyurethane-modified acrylate three-protection paint

[0052]

[0053] Table 2 Antibacterial rate test

[0054]

[0055]

[0056] As can be seen from Example 1 and Comparative Examples 1-3, the polyurethane-modified acrylate three-protection paint of Example 1 has higher tensile strength and elongation at break, and has very high antibacterial and mildew-resistant performance. At the same time, it can maintain good water resistance and salt resistance. This is mainly because the terminal isocyanate prepolymer is capped with 3-chloro-2-hydroxypropyl methacrylate, which introduces an alkene group for light-curing polymerization and a wet-curable isocyanate group at both ends, giving the polyurethane-modified acrylate good light-curing and wet-curing performance. At the same time, the active chlorine atom is introduced at the end, which can undergo quaternization with the tertiary amine group of the tertiary amine diacrylate diluent during the curing process, thereby introducing an antibacterial quaternary ammonium salt group into the molecular chain of the polyurethane-modified acrylate, giving the polyurethane paint excellent antibacterial and bactericidal performance. At the same time, the tertiary amine diacrylate diluent contains urethane groups which can form hydrogen bond cross-linking with the urethane groups in the polyurethane molecular chain, so that the polyurethane-modified acrylate has multiple cross-linking effects such as wet-curing, light-curing cross-linking, and hydrogen bond cross-linking, improving the cross-linking degree between molecular chains, and making the polyurethane film exhibit higher tensile strength and elongation at break.

[0057] Comparative Example 1 uses hydroxyethyl methacrylate instead of 3-chloro-2-hydroxypropyl methacrylate, resulting in the absence of chlorine atoms at the end of the polyurethane-modified acrylate, which cannot undergo quaternization with the tertiary amine diacrylate diluent, resulting in poor antibacterial performance of Comparative Example 1. However, the tertiary amine diacrylate diluent can undergo hydrogen bond cross-linking with the polyurethane, which is beneficial to improving the tensile properties of the polyurethane film.

[0058] Comparative Example 2 uses dipropylene glycol diacrylate as a diluent instead of a tertiary amine diacrylate diluent, which does not contain a tertiary amine group and cannot undergo quaternization with the terminal chlorine atoms of the polyurethane-modified acrylate, resulting in poor antibacterial performance and being unable to hydrogen bond with the polyurethane, resulting in poor tensile performance.

[0059] Comparative Example 3 uses 2-acrylic acid-1,1'-[(methylamino)di-2,1-ethanediyl] ester instead of a tertiary amine diacrylate diluent, which contains a tertiary amine group and can undergo quaternization with the terminal chlorine atoms of the polyurethane-modified acrylate, resulting in good antibacterial performance, but is unable to hydrogen bond with the polyurethane, resulting in poor tensile performance.

[0060] As can be seen from Examples 2-4, the polyurethane-modified acrylate three-antibiotic paints prepared from different types of polyether polyols and diisocyanate, and different amounts of tertiary amine diacrylate diluent, all have good antibacterial rates, tensile properties, and water and salt spray resistance.

Claims

1. A method for preparing a UV-moisture multi-curing polyurethane modified acrylic conformal coating, characterized in that, The preparation method includes the following steps: Step A: Under a nitrogen atmosphere, vacuum-dried and dehydrated polyether polyol, diisocyanate, 3-chloro-2-hydroxypropyl methacrylate, and N,N-dimethylformamide are added to a reaction vessel. After stirring, dibutyltin dilaurate is added dropwise. The reaction is heated and then cooled to obtain polyurethane-modified acrylate. The polyether polyol is polyethylene glycol, polypropylene glycol, or polytetrahydrofuran ether glycol, and the diisocyanate is isophorone diisocyanate or toluene-2,4-diisocyanate. Step B: Add 100 parts by weight of polyurethane-modified acrylate, with the structural formula [structure not specified], to the container. 12-18 parts by weight of tertiary amine diacrylate diluent, 0.8-1.4 parts by weight of defoamer, 0.6-1 parts by weight of leveling agent, and 0.5-1 parts by weight of thickener are mixed and stirred. Then, 3.3-3.8 parts by weight of photoinitiator are added to obtain a UV-moisture multi-curing polyurethane modified acrylic conformal paint. The preparation method of the tertiary amine diacrylate diluent includes: adding solvent, isocyanate methacrylate, N-methyldiethanolamine, and triethylamine to a reaction vessel; removing the solvent by rotary evaporation after reaction; and separating by silica gel column chromatography to obtain the tertiary amine diacrylate diluent.

2. The preparation method of the UV-moisture multi-curing polyurethane modified acrylic conformal coating according to claim 1, characterized in that, The molar ratio of the polyether polyol, diisocyanate, and 3-chloro-2-hydroxypropyl methacrylate is 1:(1.3-1.36):(0.28-0.35).

3. The preparation method of the UV-moisture multi-curing polyurethane modified acrylic conformal coating according to claim 1, characterized in that, The reaction temperature in step A is 85-95℃, and the reaction time is 1.5-3h.

4. The preparation method of the UV-moisture multi-curing polyurethane modified acrylic conformal coating according to claim 1, characterized in that, The photoinitiator is photoinitiator 1173 or photoinitiator 184.

5. The preparation method of the UV-moisture multi-curing polyurethane modified acrylic conformal coating according to claim 1, characterized in that, The solvent used in the preparation method of the tertiary amine diacrylate diluent is dichloromethane or tetrahydrofuran.

6. The preparation method of the UV-moisture multi-curing polyurethane modified acrylic conformal coating according to claim 1, characterized in that, The molar ratio of isocyanate methacrylate, N-methyldiethanolamine, and triethylamine is (2.8-3.6):1:(0.2-0.26).

7. The preparation method of the UV-moisture multi-curing polyurethane modified acrylic conformal coating according to claim 1, characterized in that, The reaction temperature in the preparation method of the tertiary amine diacrylate diluent is 20-50℃, and the reaction time is 6-12h.

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