A method for preparing antibacterial modified acrylic resin

Abstract

The invention relates to the technical field of acrylic resins, and discloses a method for preparing an antibacterial modified acrylic resin. The method comprises reacting a dibromoalkane and a phenylsiloxane tertiary amine monomer to obtain a polyphenylsiloxane quaternary ammonium salt; adding the polyphenylsiloxane quaternary ammonium salt, a defoamer, and a leveling agent to an acrylic resin emulsion, stirring and dispersing the mixture, and obtaining the antibacterial modified acrylic resin. The polyphenylsiloxane quaternary ammonium salt of the invention contains a hydrophobic benzene ring and a siloxane structure, can reduce the water absorption rate of a paint film, is conducive to improving the water resistance of the paint film, and improves heat resistance. The molecular chain of the polyphenylsiloxane quaternary ammonium salt contains an organosilicon quaternary ammonium salt group, so that the paint film exhibits a very high antibacterial zone diameter and antibacterial performance.

Description

Technical Field

[0001] The invention relates to the technical field of acrylic resins, in particular to a method for preparing an antibacterial modified acrylic resin. Background Art

[0002] Acrylic resin is a common polymer resin material with good mechanical properties, high adhesion, and excellent weather resistance. It is widely used in coatings, adhesives, inks, etc. Water-based acrylic resin uses water as a solvent and does not contain toxic and volatile organic solvents. It is green and environmentally friendly and has a wide range of applications. However, water-based acrylic resin has poor water resistance, low heat resistance, and no antibacterial properties, which limits the practical application of acrylic resin.

[0003] Adding or chemically grafting organosilicon monomers, organosilicon polymers, etc. to acrylic resin can improve its water resistance, heat resistance, mechanical strength and other properties. Patent CN105199577B discloses an antibacterial low surface energy marine antifouling coating composition, which uses quaternary ammonium salt-modified polyhydroxy fluorinated acrylic resin, terminal hydroxyl-terminated organopolysiloxane, etc. as raw materials to obtain an acrylic resin-based antifouling coating composition with good antibacterial properties, mechanical strength and other properties. Compared with the acrylic resin-based antifouling coating composition of the patent, the present invention adds polyphenylsiloxane quaternary ammonium salt to acrylic resin to obtain an acrylic resin with better heat resistance, heat resistance and antibacterial properties. Summary of the invention

[0004] The technical problem solved by the invention is to provide a method for preparing an antibacterial modified acrylic resin with good heat resistance.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is: a method for preparing an antibacterial modified acrylic resin:

[0006] (1) Add dibromoalkane and phenylsiloxane tertiary amine monomer to N,N-dimethylformamide, stir and react at 90-120°C for 24-36 hours, add ethanol to dilute the solution, filter, wash the filter cake with ethanol, and dry to obtain polyphenylsiloxane quaternary ammonium salt. The reaction formula is:

[0007]

[0008] (2) Add polyphenylsiloxane quaternary ammonium salt, defoaming agent and leveling agent to acrylic resin emulsion, stir and disperse, and obtain antibacterial modified acrylic resin.

[0009] Preferably, the molar amount of the dibromoalkane is 100-110% of the molar amount of the phenylsiloxane tertiary amine monomer.

[0010] Preferably, the dibromoalkane is any one of 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane and 1,6-dibromohexane.

[0011] Preferably, the mass of the polyphenylsiloxane quaternary ammonium salt is 2-10% of the mass of the acrylic resin emulsion.

[0012] Preferably, the preparation method of phenylsiloxane tertiary amine monomer is:

[0013] (1) Add phenyl glycidyl ether to ethanol, add an aqueous solution of dimethylamine, wherein the molar amount of dimethylamine is 140-180% of the molar amount of phenyl glycidyl ether, heat to 60-70°C, react for 6-10 hours, remove ethanol by distillation under reduced pressure, heat and evaporate until a precipitate is precipitated, then cool in an ice bath to precipitate a large amount of precipitate, filter, and dry to obtain an intermediate.

[0014] (2) Add the intermediate and pyridine to N,N-dimethylformamide, place in an ice bath, add dimethyldichlorosilane, control the molar amount of the intermediate and pyridine to be 200-220% and 200-240% of the molar amount of dimethyldichlorosilane, respectively, then react at 25-40°C for 12-18h, add water and dichloromethane, shake and let stand to separate, collect the dichloromethane extract, dry to remove water, concentrate under reduced pressure, dissolve the product in ethanol and recrystallize to obtain phenylsiloxane tertiary amine monomer. The reaction formula is:

[0015]

[0016] The beneficial effects of the present invention are as follows: phenyl glycidyl ether, dimethylamine and dimethyldichlorosilane are used as reactants to prepare a phenylsiloxane tertiary amine monomer, which then undergoes a quaternization polymerization reaction with dibromoalkanes such as 1,6-dibromohexane to obtain a polyphenylsiloxane quaternary ammonium salt, which is added to an aqueous acrylic resin emulsion, and the paint film still maintains good impact resistance and mechanical properties after curing. At the same time, the polyphenylsiloxane quaternary ammonium salt contains a hydrophobic benzene ring and a siloxane structure, which forms a hydrophobic network in the acrylic resin matrix, reduces the water absorption rate, and is beneficial to improving the water resistance of the paint film. In addition, the benzene ring and the siloxane structure have good high-temperature structural stability, and when added to the acrylic resin, the thermal decomposition temperature of the paint film can be increased, and the heat resistance can be improved.

[0017] The molecular chain of the polyphenylsiloxane quaternary ammonium salt of the present invention contains an organosilicon quaternary ammonium salt group, and the quaternary ammonium salt cation contained therein can combine with the anion in the bacterial cell membrane, destroy the structure of the cell membrane, change the permeability of the cell membrane, make the intracellular substances flow out, inhibit the growth and reproduction of bacteria, and show a very high inhibition zone diameter and antibacterial performance. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The water-based acrylic resin emulsion of the present invention has a model number of YoungSun AC 6127, produced by Guangzhou Yangsong Technology Co., Ltd. The defoamer has a model number of DAPRO DF 675, produced by Jining Fangyu Chemical Co., Ltd. The leveling agent has a model number of EFKA-3650, produced by Jining Fangyu Chemical Co., Ltd.

[0020] Example 1

[0021] (1) Add 60 mmol of phenyl glycidyl ether and 10 mL of an aqueous solution containing 96 mmol of dimethylamine to 150 mL of ethanol, heat to 65°C, react for 10 h, remove ethanol by distillation under reduced pressure, control the vacuum degree to -30 Pa, heat to 100°C, evaporate until a precipitate is precipitated, then cool in an ice bath to precipitate a large amount of precipitate, filter, and dry at 90°C for 8 h to obtain an intermediate.

[0022] (2) Add 66 mmol of the intermediate and 72 mmol of pyridine to 180 mL of N,N-dimethylformamide, place in an ice bath, add 30 mmol of dimethyldichlorosilane, and then react at 25°C for 18 h. Add 300 mL of water and 200 mL of dichloromethane. After shaking, let stand to separate the layers. Collect the dichloromethane extract, dry with anhydrous sodium sulfate to remove water, filter, and concentrate the filtrate under reduced pressure. Control the vacuum degree to -10 Pa. Dissolve the product in 200 mL of ethanol and recrystallize to obtain a phenylsiloxane tertiary amine monomer.

[0023] (3) Add 84 mmol 1,6-dibromohexane and 80 mmol phenylsiloxane tertiary amine monomer to 350 mL N,N-dimethylformamide, stir the mixture at 110 °C for 36 h at a stirring rate of 1500 r / min, add 800 mL ethanol to dilute the solution, filter with suction, wash the filter cake with ethanol, and dry at 80 °C for 2 h to obtain polyphenylsiloxane quaternary ammonium salt.

[0024] (4) Add 20 g of polyphenylsiloxane quaternary ammonium salt, 2 g of defoamer, and 4 g of leveling agent to 1 kg of acrylic resin emulsion, stir and disperse for 20 min at a stirring rate of 3000 r / min to obtain an antibacterial modified acrylic resin.

[0025] Example 2

[0026] (1) Add 60 mmol of phenyl glycidyl ether and 10 mL of an aqueous solution containing 84 mmol of dimethylamine to 100 mL of ethanol, heat to 70°C, react for 6 h, remove ethanol by distillation under reduced pressure, control the vacuum degree to -10 Pa, heat to 100°C, evaporate until a precipitate is precipitated, then cool in an ice bath to precipitate a large amount of precipitate, filter, and dry at 100°C for 5 h to obtain an intermediate.

[0027] (2) Add 66 mmol of the intermediate and 72 mmol of pyridine to 200 mL of N,N-dimethylformamide, place in an ice bath, add 30 mmol of dimethyldichlorosilane, and then react at 25°C for 18 h. Add 300 mL of water and 200 mL of dichloromethane. After shaking, let stand to separate the layers. Collect the dichloromethane extract, dry with anhydrous sodium sulfate to remove water, filter, and concentrate the filtrate under reduced pressure. Control the vacuum degree to -10 Pa. Dissolve the product in 200 mL of ethanol and recrystallize to obtain a phenylsiloxane tertiary amine monomer.

[0028] (3) Add 80 mmol of 1,2-dibromoethane and 80 mmol of phenylsiloxane tertiary amine monomer to 250 mL of N,N-dimethylformamide, stir the mixture at 90 °C for 36 h at a stirring rate of 1500 r / min, add 600 mL of ethanol to dilute the solution, filter with suction, wash the filter cake with ethanol, and dry at 70 °C for 5 h to obtain polyphenylsiloxane quaternary ammonium salt.

[0029] (4) Add 50 g of polyphenylsiloxane quaternary ammonium salt, 8 g of defoaming agent, and 3 g of leveling agent to 1 kg of acrylic resin emulsion, stir and disperse for 30 min at a stirring rate of 2000 r / min to obtain an antibacterial modified acrylic resin.

[0030] Example 3

[0031] (1) Add 60 mmol of phenyl glycidyl ether and 10 mL of an aqueous solution containing 84 mmol of dimethylamine to 100 mL of ethanol, heat to 60°C, react for 10 h, remove ethanol by distillation under reduced pressure, control the vacuum degree to -10 Pa, heat to 100°C, evaporate until a precipitate is precipitated, then cool in an ice bath to precipitate a large amount of precipitate, filter, and dry at 100°C for 6 h to obtain an intermediate.

[0032] (2) Add 60 mmol of the intermediate and 60 mmol of pyridine to 160 mL of N,N-dimethylformamide, place in an ice bath, add 30 mmol of dimethyldichlorosilane, and then react at 40°C for 12 h. Add 300 mL of water and 200 mL of dichloromethane. After shaking, let stand to separate the layers. Collect the dichloromethane extract, dry with anhydrous sodium sulfate to remove water, filter, and concentrate the filtrate under reduced pressure. Control the vacuum degree to -30 Pa. Dissolve the product in 200 mL of ethanol and recrystallize to obtain a phenylsiloxane tertiary amine monomer.

[0033] (3) Add 88 mmol 1,4-dibromobutane and 80 mmol phenylsiloxane tertiary amine monomer to 300 mL N,N-dimethylformamide, stir the mixture at 120 °C for 24 h at a stirring rate of 1000 r / min, add 800 mL ethanol to dilute the solution, filter with suction, wash the filter cake with ethanol, and dry at 70 °C for 5 h to obtain polyphenylsiloxane quaternary ammonium salt.

[0034] (4) Add 80 g of polyphenylsiloxane quaternary ammonium salt, 4 g of defoamer, and 5 g of leveling agent to 1 kg of acrylic resin emulsion, stir and disperse for 20 min at a stirring rate of 3000 r / min to obtain an antibacterial modified acrylic resin.

[0035] Example 4

[0036] (1) Add 60 mmol of phenyl glycidyl ether and 15 mL of an aqueous solution containing 108 mmol of dimethylamine to 150 mL of ethanol, heat to 65°C, react for 10 h, remove ethanol by distillation under reduced pressure, control the vacuum degree to -10 Pa, heat to 100°C, evaporate until a precipitate is precipitated, then cool in an ice bath to precipitate a large amount of precipitate, filter, and dry at 100°C for 5 h to obtain an intermediate.

[0037] (2) Add 63 mmol of the intermediate and 66 mmol of pyridine to 200 mL of N,N-dimethylformamide, place in an ice bath, add 30 mmol of dimethyldichlorosilane, and then react at 30°C for 12 h. Add 300 mL of water and 200 mL of dichloromethane. After shaking, let stand to separate the layers. Collect the dichloromethane extract, dry with anhydrous sodium sulfate to remove water, filter, and concentrate the filtrate under reduced pressure. Control the vacuum degree to -30 Pa. Dissolve the product in 200 mL of ethanol and recrystallize to obtain a phenylsiloxane tertiary amine monomer.

[0038] (3) Add 88 mmol 1,5-dibromopentane and 80 mmol phenylsiloxane tertiary amine monomer to 350 mL N,N-dimethylformamide, stir the mixture at 90 °C for 36 h at a stirring rate of 2000 r / min, add 800 mL ethanol to dilute the solution, filter with suction, wash the filter cake with ethanol, and dry at 80 °C for 2 h to obtain polyphenylsiloxane quaternary ammonium salt.

[0039] (4) Add 100 g of polyphenylsiloxane quaternary ammonium salt, 2 g of defoaming agent, and 5 g of leveling agent to 1 kg of acrylic resin emulsion, stir and disperse for 30 min at a stirring rate of 3000 r / min to obtain an antibacterial modified acrylic resin.

[0040] Comparative Example 1

[0041] (1) Add 2 g of defoamer and 4 g of leveling agent to 1 kg of acrylic resin emulsion, stir and disperse for 20 min at a stirring rate of 3000 r / min to obtain an antibacterial modified acrylic resin.

[0042] Comparative Example 2

[0043] (1) Add 84 mmol 1,6-dibromohexane and 80 mmol N,N,N',N'-tetramethylethylenediamine to 350 mL N,N-dimethylformamide, stir the mixture at 110°C for 36 h at a stirring rate of 1500 r / min, add 800 mL ethanol to dilute the solution, filter with suction, wash the filter cake with ethanol, and dry at 80°C for 2 h to obtain a polyquaternary ammonium salt.

[0044] (2) Add 20 g of polyquaternary ammonium salt, 2 g of defoaming agent, and 4 g of leveling agent to 1 kg of acrylic resin emulsion, stir and disperse for 20 min at a stirring rate of 3000 r / min to obtain an antibacterial modified acrylic resin.

[0045] Comparative Example 3

[0046] (1) Add 66 mmol 3-dimethylamino-1-propanol and 72 mmol pyridine to 180 mL N,N-dimethylformamide, place in an ice bath, add 30 mmol dimethyldichlorosilane, and then react at 25°C for 18 h. Add 300 mL water and 200 mL dichloromethane. After shaking, let stand to separate the layers. Collect the dichloromethane extract, dry with anhydrous sodium sulfate to remove water, filter and concentrate the filtrate under reduced pressure, wash with petroleum ether, and dry at 80°C for 2 h to obtain a siloxane tertiary amine monomer.

[0047] (2) Add 84 mmol 1,6-dibromohexane and 80 mmol siloxane tertiary amine monomer to 350 mL N,N-dimethylformamide, stir the mixture at 110 °C for 36 h at a stirring rate of 1500 r / min, add 800 mL ethanol to dilute the solution, filter with suction, wash the filter cake with ethanol, and dry at 80 °C for 2 h to obtain polysiloxane quaternary ammonium salt.

[0048] (3) Add 20 g of polysiloxane quaternary ammonium salt, 2 g of defoamer, and 4 g of leveling agent to 1 kg of acrylic resin emulsion, stir and disperse for 20 min at a stirring rate of 3000 r / min to obtain an antibacterial modified acrylic resin.

[0049] Pour the antibacterial modified acrylic resin on the surface of the tinplate substrate and heat cure it at 120℃ for 3h to form a paint film. Test the impact resistance according to GB / T 1732-2020 method.

[0050] A paint film with a specification of 8cm×8cm×0.2cm was dried, weighed, and then placed in deionized water and soaked for 48 hours. The paint film was taken out, the residual water on the surface was wiped off, and the film was weighed to calculate the water absorption rate Q.

[0051] Q = (M-M0) / M0 × 100%. M0 is the mass of the paint film before absorbing water, and M is the mass of the paint film after absorbing water.

[0052] The paint film was subjected to a thermal performance test in a thermal performance analyzer under a nitrogen atmosphere, with the temperature rising from room temperature to 700°C at a heating rate of 10°C / min.

[0053] The paint film was made into a circular film with a radius of 4 cm and a thickness of 0.1 mm, and sterilized under ultraviolet light. 0.5 mL of the activated test bacterial suspension (concentration of 10 6 cfu / mL) and coated on the surface of agar medium, the sterilized paint film was placed close to the surface of the medium, cultured in a constant temperature and humidity incubator at 37°C for 24 hours, and then the diameter of the inhibition zone was measured. The larger the diameter of the inhibition zone, the better the antibacterial performance. The test bacteria were Escherichia coli and Staphylococcus aureus.

[0054] Table 1

[0055]

[0056] As shown in Table 1, the acrylic resin of Comparative Example 1 has a relatively large water absorption rate of 9.6%, and poor water resistance. In addition, the mass loss temperature is relatively low, and the heat resistance is poor. At the same time, it does not show an inhibition zone diameter for Escherichia coli and Staphylococcus aureus, and has no antibacterial properties.

[0057] Polyphenylsiloxane quaternary ammonium salt has been added in the acrylic resin of embodiment 1-4, acrylic resin still keeps good impact resistance and mechanical property, contains hydrophobic benzene ring and siloxane structure in the polyphenylsiloxane quaternary ammonium salt simultaneously, forms hydrophobic network in acrylic resin matrix, is conducive to improving the water resistance of paint film, thereby reduces water absorption rate.And benzene ring and siloxane structure have good high temperature structure stability, can improve the thermal decomposition temperature of paint film, improve heat resistance.And contain organosilicon quaternary ammonium salt group in the molecular chain of polyphenylsiloxane quaternary ammonium salt, the quaternary ammonium salt cation it contains can be combined with the negatively charged ion in the bacterial cell membrane, destroys cell membrane structure, changes the permeability of cell membrane, makes intracellular material flow out, suppresses the growth and reproduction of bacteria, improves the inhibition zone diameter and the antibacterial property of paint film to bacteria.

[0058] Comparative Example 2 uses 1,6-dibromohexane and N,N,N',N'-tetramethylethylenediamine to react to obtain polyquaternary ammonium salt. Since the quaternary ammonium salt group has strong hydrophilicity and the polyquaternary ammonium salt does not contain hydrophobic benzene rings and siloxane structures, the hydrophilicity of the paint film becomes greater and the water absorption rate increases, thereby affecting the water resistance of the paint film. In addition, the thermal decomposition temperature of the paint film is low and the heat resistance is poor.

[0059] Comparative Example 3 uses siloxane tertiary amine monomer and 1,6-dibromohexane for polymerization reaction, and the obtained polysiloxane quaternary ammonium salt does not contain a benzene ring structure. The water absorption rate of the paint film is slightly higher than that of each embodiment, and the thermal decomposition temperature is slightly lower than that of each embodiment.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an antibacterial modified acrylic resin, characterized in that: The preparation method is: (1) Adding dibromoalkane and phenylsiloxane tertiary amine monomer to N,N-dimethylformamide to react, adding ethanol to dilute the solution, filtering, washing the filter cake with ethanol, and drying at 70-80° C. for 2-5 hours to obtain polyphenylsiloxane quaternary ammonium salt; The structural formula of the phenylsiloxane tertiary amine monomer is ; (2) adding polyphenylsiloxane quaternary ammonium salt, defoamer and leveling agent to the acrylic resin emulsion, stirring and dispersing for 20-30 minutes at a stirring rate of 2000-3000 r / min to obtain an antibacterial modified acrylic resin; The molar amount of the dibromoalkane is 100-110% of the molar amount of the phenylsiloxane tertiary amine monomer.

2. The method for preparing the antibacterial modified acrylic resin according to claim 1, characterized in that: The reaction is stirred at 90-120° C. for 24-36 h at a stirring rate of 1000-2000 r / min.

3. The method for preparing the antibacterial modified acrylic resin according to claim 1, characterized in that: The dibromoalkane is any one of 1,2-dibromoethane, 1,4-dibromobutane, 1,5-dibromopentane and 1,6-dibromohexane.

4. The method for preparing the antibacterial modified acrylic resin according to claim 1, characterized in that: The mass of the polyphenylsiloxane quaternary ammonium salt is 2-10% of the mass of the acrylic resin emulsion.

5. The method for preparing the antibacterial modified acrylic resin according to claim 1, characterized in that: The preparation method of the phenylsiloxane tertiary amine monomer is: (1) Add phenyl glycidyl ether to ethanol, add an aqueous solution of dimethylamine, heat to 60-70°C, react for 6-10 hours, remove ethanol by distillation under reduced pressure, control the vacuum degree to -10 to -30 Pa, heat to 100°C, evaporate until a precipitate is precipitated, then cool in an ice bath, precipitate, filter, and dry at 90-100°C for 5-8 hours to obtain an intermediate; (2) Add the intermediate and pyridine to N,N-dimethylformamide, place in an ice bath, add dimethyldichlorosilane, and then react at 25-40°C for 12-18h, add water and dichloromethane, shake and let stand to separate, collect the dichloromethane extract, dry with anhydrous sodium sulfate to remove water, filter and concentrate the filtrate under reduced pressure, control the vacuum degree to -10 to -30Pa, dissolve the product in ethanol, and recrystallize to obtain a phenylsiloxane tertiary amine monomer.

6. The method for preparing the antibacterial modified acrylic resin according to claim 5, characterized in that: In the above (1), the molar amount of dimethylamine is 140-180% of the molar amount of phenyl glycidyl ether.

7. The method for preparing the antibacterial modified acrylic resin according to claim 5, characterized in that: In the above (2), the molar amounts of the intermediate and pyridine are 200-220% and 200-240% of the molar amount of dimethyldichlorosilane, respectively.

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