A hydroxyl fluorosilicone oil modified waterborne silicone antifoam

Abstract

The application relates to a hydroxyl fluorosilicone oil modified water-based organic silicon defoaming agent and belongs to the technical field of defoaming agents. The hydroxyl fluorosilicone oil modified water-based organic silicon defoaming agent comprises the following components in parts by mass: 5-50 parts of polydimethylsiloxane, 0.1-5 parts of hydroxyl fluorosilicone oil, 0.1-5 parts of white carbon black, 1-30 parts of polyether modified silicone oil, 1-30 parts of emulsifier, 0-5 parts of thickening agent and 20-90 parts of deionized water, wherein the proportion of fluorine elements in the total components except the deionized water is not less than 0.5 wt%. The hydroxyl fluorosilicone oil is chemically bonded with the polyether modified organic silicon in situ, the stability of the defoaming agent is improved, and good defoaming effect on a strong foaming system at an extremely low dosage can be realized.

Description

Technical Field

[0001] This invention relates to a hydroxyl fluorosilicone oil modified waterborne organosilicon defoamer; belonging to the field of defoamer technology. Background Technology

[0002] Water-based defoamers are widely used in coatings, water treatment, agrochemicals, and daily chemicals. Due to varying application conditions in different fields, a single general-purpose defoamer often cannot meet the needs of multiple applications. Therefore, specific defoamers need to be developed for different application systems. For example, in the agrochemical field, defoamers with good acid and alkali resistance are often required. Furthermore, different addition processes place different demands on defoamer performance. For instance, single-addition processes typically require higher defoaming suppression properties; continuous addition processes require better instantaneous defoaming properties. Simultaneously, defoamers are usually used as additives and need good compatibility with other auxiliaries; otherwise, demulsification and failure may occur. Therefore, the stability of defoamers also has certain requirements.

[0003] On the other hand, the overall cost-effectiveness of defoamers is also a parameter that needs to be considered in practical applications. Firstly, there is the balance between raw material cost and performance. For example, using single-polyether or single-silicone defoamers is inexpensive, but their application areas are narrow and they are difficult to apply under harsh conditions. Secondly, there is the balance between dosage and performance. Currently, commonly used general-purpose polyether-modified silicone defoamers can combine good defoaming properties with stability, but at low dosages, they often perform worse than single-silicone defoamers, mainly because the former has a slightly higher surface tension. Therefore, adding fluorine to polyether-modified silicone defoamers is an effective way to reduce surface tension. For example, Chinese invention patents CN202210364140 and CN201710264878 introduce fluorine into defoamers by grafting fluoroalkyl ethylene with hydrogen-containing silicone oil; Chinese invention patents CN202210207158 and CN202010448993 introduce fluorine by grafting allyl polyether with hydrogen-fluorinated silicone oil; methyl, vinyl, and hydrogen-fluorinated silicone oils can also be directly applied to defoamer formulations (Chinese invention patents CN201210347025 and CN201310134731, etc.) to improve the acid and alkali resistance of defoamers; in addition, there are also methods to prepare fluorosilicone oils with special structures (Chinese invention patent CN201410648599) to achieve defoaming in special systems. However, some of the current technical solutions involve complex and demanding processes, some have high costs for fluorinated raw materials, and some require the addition of high fluorine content to achieve good results, resulting in limited overall cost-effectiveness. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a water-based silicone defoamer modified with hydroxyl fluorosilicone oil. The silicone defoamer of this invention exhibits excellent defoaming performance under both conventional and harsh conditions, and demonstrates superior storage stability.

[0005] The technical solution of the present invention to solve the above problems is as follows:

[0006] A hydroxyl fluorosilicone oil modified waterborne silicone defoamer, comprising the following components in parts by weight:

[0007] The ingredients are: 5-50 parts of polydimethylsiloxane, 0.1-5 parts of hydroxyl fluorosilicone oil, 0.1-5 parts of silica, 1-30 parts of polyether modified silicone oil, 1-30 parts of emulsifier, 0-5 parts of thickener, and 20-90 parts of deionized water, wherein the proportion of fluorine in the total components excluding deionized water is not less than 0.5 wt%.

[0008] As a preferred embodiment of the above technical solution, the hydroxyl fluorosilicone oil-modified waterborne silicone defoamer comprises the following components in parts by weight:

[0009] 5-20 parts of polydimethylsiloxane, 0.1-2 parts of hydroxyl fluorosilicone oil, 0.1-2 parts of silica, 2-6 parts of polyether modified silicone oil, 2-10 parts of emulsifier, 0-1 part of thickener, and 20-90 parts of deionized water.

[0010] As a preferred embodiment of the above technical solution, the viscosity of the polydimethylsiloxane is 300~2000 cP.

[0011] The hydroxyl fluorosilicone oil mentioned above is obtained by ring-opening polymerization of fluorosilane rings and deionized water under the action of an acid catalyst. oh, oh -Dihydroxy polyfluorosiloxane, obtained by ring-opening copolymerization of fluorosilane cyclic compound, dimethylsiloxane cyclic compound, and deionized water under the action of an acid catalyst. oh, oh - At least one of dihydroxy poly(fluorosiloxane-dimethylsiloxane).

[0012] Preferably, the fluorinated silane cyclic compound is either trifluoropropylmethylsiloxane cyclic compound or nonafluorohexylmethylsiloxane cyclic compound; the acid catalyst is a protic acid.

[0013] As a preferred embodiment of the above technical solution, the specific surface area of ​​the silica is not less than 160 m². 2 / g.

[0014] As a preferred embodiment of the above technical solution, the viscosity of the hydroxyl fluorosilicone oil is 50~500 cP.

[0015] As a preferred embodiment of the above technical solution, the polyether-modified silicone oil is obtained by hydrosilylation of monoallyl-terminated polyether with hydrogen-containing silicone oil under the action of a platinum catalyst.

[0016] Preferably, the monoallyl-terminated polyether has the general structural formula as follows:

[0017] CH2=CHCH2O(CH2CH2O) m (CH(CH3)CH20) n R,

[0018] Wherein, m is 2~20, n is 0~30, R is hydrogen or a C1-C4 saturated alkyl group, and m and n are both positive integers; the hydrogen content of the hydrogen-containing silicone oil is 0.05~0.4wt%; the platinum catalyst is any one of a cassiterite catalyst or a chloroplatinic acid catalyst.

[0019] As a preferred embodiment of the above technical solution, the emulsifier is at least one of Span 20, Tween 20, Span 60, Tween 60, Span 80, and Tween 80.

[0020] As a preferred embodiment of the above technical solution, the thickener is at least one selected from hydroxypropyl cellulose, sodium carboxymethyl cellulose, polyvinyl alcohol, polyethylene oxide, sodium alginate, polyacrylamide, and sodium polyacrylate.

[0021] Another object of the present invention is to provide a method for preparing the above-mentioned organosilicon defoamer.

[0022] A method for preparing a hydroxyl fluorosilicone oil-modified waterborne organosilicon defoamer includes the following steps:

[0023] Take 5-50 parts of polydimethylsiloxane and 0.1-5 parts of... oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane and 0.1-5 parts of fumed silica are mixed at 120-140℃ for 1-3 hours; the mixture is then cooled to 50-70℃, and 1-30 parts of the above polyether-modified silicone oil, 1-30 parts of emulsifier, 0-5 parts of thickener, and 20-90 parts of deionized water are added and mixed evenly to obtain a hydroxyl fluorosilicone oil-modified waterborne organosilicon defoamer.

[0024] As a preferred embodiment of the above technical solution, the preparation method of the hydroxyl fluorosilicone oil modified waterborne organosilicon defoamer includes the following steps:

[0025] Take 5-40 parts of polydimethylsiloxane and 0.1-3 parts of... oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane and 0.1-3 parts of fumed silica are mixed at 120-140℃ for 1-3 hours; the mixture is then cooled to 50-70℃, and 2-15 parts of the above polyether-modified silicone oil, 2-15 parts of emulsifier, 0-1 part of thickener, and 30-90 parts of deionized water are added and mixed evenly to obtain a hydroxyl fluorosilicone oil-modified waterborne organosilicon defoamer.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention utilizes in-situ chemical bonding between hydroxyl fluorosilicone oil and polyether-modified organosilicon to improve the stability of the defoamer, while achieving good defoaming effect on strongly foaming systems at extremely low dosages. By adjusting the structure of the hydroxyl fluorosilicone oil, the amount of fluorine introduced can be controlled, thereby improving the overall cost-effectiveness. At the same time, it achieves applicability to a wide range of silica, polyether-modified silicone oils, and emulsifiers. Detailed Implementation

[0028] The following specific embodiments are merely illustrative of the invention and are not intended to limit it. Any modifications made by those skilled in the art after reading this specification, as long as they fall within the scope of the claims, will be protected by patent law.

[0029] Example 1

[0030] Under nitrogen protection, 250 parts of polyether CH2=CHCH2O(CH2CH2O)5(CH(CH3)CH2O)3H were taken, and 1.4 parts of chloroplatinic acid (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (containing hydrogen in the side chain and terminal methyl, with a hydrogen content of 0.40%) were added. The mixture was reacted at 120°C for 3-4 hours to obtain polyether-modified polysiloxane.

[0031] Take 500 parts of trifluoropropylmethylcyclotrisiloxane, 5 parts of deionized water, add 2 parts of trifluoromethanesulfonic acid, and stir at 130℃ for 8 hours. After post-treatment, obtain... oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane, viscosity 250 cP.

[0032] Take 90 parts of polydimethylsiloxane with a viscosity of 600 cP and 5 parts of the above-mentioned polydimethylsiloxane with a viscosity of 250 cP. oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane, 5 parts fumed silica (specific surface area 200 m²) 2 The mixture (g) was stirred at 130°C for 2 hours. The mixture was then cooled to 60°C, and 40 parts of the above-mentioned polyether-modified polysiloxane, 25 parts of a mixture of Span 60 and Tween 60, 2 parts of sodium carboxymethyl cellulose, and 250 parts of deionized water were added. The mixture was stirred until homogeneous to obtain the fluorinated water-based defoamer. Calculations showed that fluorine accounted for 1.1% of the components excluding deionized water.

[0033] Example 2

[0034] Under nitrogen protection, 660 parts of polyether CH2=CHCH2O(CH2CH2O) were taken. 18 (CH(CH3)CH20) 12 Add 1.4 parts of chloroplatinic acid (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (containing hydrogen in the side chain and terminal methyl, with a hydrogen content of 0.40%), and react at 120°C for 3-4 hours to obtain polyether-modified polysiloxane.

[0035] Take 90 parts of polydimethylsiloxane with a viscosity of 900 cP and 5 parts of the polydimethylsiloxane with a viscosity of 250 cP from Example 1. oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane, 5 parts fumed silica (specific surface area 220 m²) 2 The mixture (g) was stirred at 130°C for 2 hours. The mixture was then cooled to 60°C, and 30 parts of the above-mentioned polyether-modified polysiloxane, 35 parts of Span 60, 1 part of polyethylene oxide, and 660 parts of deionized water were added. The mixture was stirred until homogeneous to obtain the fluorinated water-based defoamer. Calculations showed that fluorine accounted for 1.1% of the components excluding deionized water.

[0036] Example 3

[0037] Under nitrogen protection, 120 parts of polyether CH2=CHCH2O(CH2CH2O)4H were taken, and 1.4 parts of caster catalyst (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (containing hydrogen in the side chain and terminal methyl, with a hydrogen content of 0.40%) were added. The mixture was reacted at 120°C for 3-4 hours to obtain polyether-modified polysiloxane.

[0038] Take 500 parts of trifluoropropylmethylcyclotrisiloxane, 10 parts of deionized water, add 2 parts of trifluoromethanesulfonic acid, and stir at 130℃ for 8 hours. After post-treatment, obtain... oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane, viscosity 100 cP.

[0039] Take 90 parts of polydimethylsiloxane with a viscosity of 800 cP, and 5 parts of the above-mentioned polydimethylsiloxane with a viscosity of 100 cP. oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane, 5 parts hydrophobic silica (specific surface area 160 m²) 2 The mixture (g) was stirred at 130°C for 2 hours. The mixture was then cooled to 60°C, and 35 parts of the above-mentioned polyether-modified polysiloxane, 35 parts of a mixture of Span 80 and Tween 60, 4 parts of sodium carboxymethyl cellulose, and 660 parts of deionized water were added. The mixture was stirred until homogeneous to obtain a fluorinated water-based defoamer. Calculations showed that fluorine accounted for 1.1% of the components excluding deionized water.

[0040] Example 4

[0041] Under nitrogen protection, take 100 parts of polyether CH2=CHCH2O(CH2CH2O). 22 (CH(CH3)CH20) 22 H, add 0.3 parts of chloroplatinic acid (containing 0.5% platinum) and 120 parts of hydrogen-containing silicone oil (containing hydrogen in the side chain and terminal methyl, with a hydrogen content of 0.083%), and react at 120°C for 3-4 hours to obtain polyether-modified polysiloxane.

[0042] Take 92 parts of polydimethylsiloxane with a viscosity of 1000 cP and 3 parts of the polydimethylsiloxane with a viscosity of 250 cP from Example 1. oh, oh- Dihydroxy polytrifluoropropylmethylsiloxane, 5 parts ultrafine silica (specific surface area 240 m²) 2 The mixture (g) was stirred at 130°C for 2 hours. The mixture was then cooled to 60°C, and 35 parts of the above-mentioned polyether-modified polysiloxane, 35 parts of a mixture of Span 60 and Tween 60, and 660 parts of deionized water were added. The mixture was stirred until homogeneous to obtain the fluorinated water-based defoamer. Calculations showed that fluorine accounted for 0.65% of the components excluding deionized water.

[0043] Example 5

[0044] Under nitrogen protection, 130 parts of polyether (CH2=CHCH2OCH2CH2O(CH(CH3)CH2O)) were taken. 10 Add 0.6 parts of chloroplatinic acid (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (containing hydrogen in the side chain and terminal methyl groups, with a hydrogen content of 0.18%), and react at 120°C for 3-4 hours to obtain polyether-modified polysiloxane.

[0045] Take 90 parts of polydimethylsiloxane with a viscosity of 1200 cP and 5 parts of the polydimethylsiloxane with a viscosity of 250 cP from Example 1. oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane, 5 parts hydrophobic silica (specific surface area 170 m²) 2 The mixture (g) was stirred at 130℃ for 2 hours. The mixture was then cooled to 60℃, and 40 parts of the above-mentioned polyether-modified polysiloxane, 25 parts of a mixture of Span 20 and Tween 20, 4 parts of sodium alginate, and 660 parts of deionized water were added. The mixture was stirred until homogeneous to obtain the fluorinated water-based defoamer. Calculations showed that fluorine accounted for 1.1% of the components excluding deionized water.

[0046] Example 6

[0047] Under nitrogen protection, 280 parts of polyether CH2=CHCH2O(CH2CH2O) were taken. 15 (CH(CH3)CH20) 18 H, add 0.6 parts of caster catalyst (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (containing hydrogen on the side chain and terminal methyl, with a hydrogen content of 0.14%), and react at 120℃ for 3~4h to obtain polyether-modified polysiloxane.

[0048] Take 300 parts of a mixture of trifluoropropylmethylcyclotrisiloxane and 200 parts of dimethylcyclosiloxane, 10 parts of deionized water, add 5 parts of sulfuric acid, and stir at 130°C for 8 hours. After post-treatment, obtain... oh, oh - Dihydroxy poly(trifluoropropylmethylsiloxane-dimethylsiloxane), viscosity 100 cP.

[0049] Take 90 parts of polydimethylsiloxane with a viscosity of 900 cP, and 5 parts of the above-mentioned polydimethylsiloxane with a viscosity of 100 cP. oh, oh- Dihydroxy poly(trifluoropropylmethylsiloxane-dimethylsiloxane), 5 parts fumed silica (specific surface area 200 m²) 2 The mixture (g) was stirred at 130°C for 2 hours. The mixture was then cooled to 60°C, and 30 parts of the above-mentioned polyether-modified polysiloxane, 30 parts of a mixture of Span 60 and Tween 60, 1 part of hydroxypropyl cellulose, and 110 parts of deionized water were added. The mixture was stirred until homogeneous to obtain the fluorinated water-based defoamer. Calculations showed that fluorine accounted for 0.64% of the components excluding deionized water.

[0050] Example 7

[0051] Under nitrogen protection, 230 parts of polyether CH2=CHCH2O(CH2CH2O) were taken. 15 (CH(CH3)CH20) 19 CH3 was mixed with 0.3 parts of caster catalyst (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (end-hydrogen, hydrogen content 0.096%), and reacted at 120℃ for 3-4 h to obtain polyether-modified polysiloxane.

[0052] Take 90 parts of polydimethylsiloxane with a viscosity of 700 cP, and 2.5 parts of the polydimethylsiloxane with a viscosity of 100 cP from Example 3. oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane, 2.5 parts of the 100 cP viscosity from Example 6 oh, oh - Dihydroxy poly(trifluoropropylmethylsiloxane-dimethylsiloxane), 5 parts fumed silica (specific surface area 200 m²) 2 The mixture (g) was stirred at 130℃ for 2 hours. The mixture was then cooled to 60℃, and 50 parts of the above-mentioned polyether-modified polysiloxane, 50 parts of a mixture of Span 80 and Tween 80, 5 parts of sodium carboxymethyl cellulose, and 1800 parts of deionized water were added. The mixture was stirred until homogeneous to obtain the fluorinated water-based defoamer. Calculations showed that fluorine accounted for 0.72% of the components excluding deionized water.

[0053] Example 8

[0054] Under nitrogen protection, take 80 parts of polyether CH2=CHCH2O(CH2CH2O). 13 Add 0.3 parts of caster catalyst (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (containing hydrogen in the side chain and methyl at the end, with a hydrogen content of 0.083%) to (CH(CH3)CH2O)3H, and react at 120℃ for 3-4 hours to obtain polyether-modified polysiloxane.

[0055] Take 500 parts of nonafluorohexylmethylcyclotrisiloxane, 15 parts of deionized water, add 20 parts of acidic clay, and stir at 130℃ for 10 hours. After post-treatment, obtain... oh, oh - Dihydroxy polynonafluorohexylmethylsiloxane, viscosity 250 cP.

[0056] Take 90 parts of polydimethylsiloxane with a viscosity of 1500 cP and 5 parts of the above-mentioned medium viscosity of 250 cP. oh, oh - Dihydroxy polynonafluorohexylmethylsiloxane, 5 parts fumed silica (specific surface area 220 m²) 2 The mixture (g) was stirred at 130°C for 2 hours. The mixture was then cooled to 60°C, and 30 parts of the above-mentioned polyether-modified polysiloxane, 30 parts of Span 80, 1 part of sodium polyacrylate, and 660 parts of deionized water were added and mixed thoroughly to obtain the fluorinated waterborne defoamer. Calculations showed that fluorine accounted for 1.6% of the components excluding deionized water.

[0057] Example 9

[0058] Under nitrogen protection, 300 parts of polyether CH2=CHCH2O(CH2CH2O) were taken. 15 (CH(CH3)CH20) 19 CH3 was mixed with 0.5 parts of caster catalyst (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (containing hydrogen in the side chain and terminal methyl groups, with a hydrogen content of 0.14%), and reacted at 120°C for 3-4 hours to obtain polyether-modified polysiloxane.

[0059] Take 200 parts of a mixture of nonafluorohexylmethylcyclotrisiloxane and 250 parts of dimethylcyclosiloxane, 15 parts of deionized water, add 20 parts of cation exchange resin, and stir at 130℃ for 8 hours. After post-treatment, obtain... oh, oh - Dihydroxy poly(nonafluorohexylmethylsiloxane-dimethylsiloxane), viscosity 300 cP.

[0060] Take 87 parts of polydimethylsiloxane with a viscosity of 800 cP and 5 parts of the above-mentioned polydimethylsiloxane with a viscosity of 300 cP. oh, oh - Dihydroxy poly(nonafluorohexylmethylsiloxane-dimethylsiloxane), 8 parts silica (specific surface area 180 m²) 2 The mixture (g) was stirred at 130℃ for 2 hours. The mixture was then cooled to 60℃, and 50 parts of the above-mentioned polyether-modified polysiloxane, 40 parts of a mixture of Span 60 and Tween 80, 6 parts of polyacrylamide, and 770 parts of deionized water were added. The mixture was stirred until homogeneous to obtain the fluorinated water-based defoamer. Calculations showed that fluorine accounted for 0.62% of the components excluding deionized water.

[0061] Example 10

[0062] Under nitrogen protection, 350 parts of polyether CH2=CHCH2O(CH2CH2O)6(CH(CH3)CH2O)4H were taken, and 2.1 parts of caster catalyst (containing 0.5% platinum) and 100 parts of hydrogen-containing silicone oil (containing hydrogen in the side chain and at the end, with a hydrogen content of 0.60%) were added. The mixture was reacted at 120°C for 3-4 hours to obtain polyether-modified polysiloxane.

[0063] Take 90 parts of polydimethylsiloxane with a viscosity of 900 cP and 5 parts of the polydimethylsiloxane with a viscosity of 250 cP from Example 1. oh, oh - Dihydroxy polytrifluoropropylmethylsiloxane, 5 parts fumed silica (specific surface area 200 m²) 2 The mixture (g) was stirred at 130°C for 2 hours. The mixture was then cooled to 60°C, and 20 parts of the above-mentioned polyether-modified polysiloxane, 20 parts of the polyether-modified polysiloxane described in Example 7, 25 parts of Span 60, 0.5 parts of polyvinyl alcohol, and 660 parts of deionized water were added. The mixture was stirred until homogeneous to obtain the fluorinated water-based defoamer. Calculations showed that fluorine accounted for 1.1% of the components excluding deionized water.

[0064] Comparative Example 1

[0065] Commercially available water-based defoamers mainly consist of polydimethylsiloxane, silica, polyether-modified polysiloxane, and water.

[0066] Comparative Example 2

[0067] Take 90 parts of polydimethylsiloxane with a viscosity of 900 cP, 5 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 100 cP, and 5 parts of fumed silica (specific surface area 220 m²). 2 Mix the polyether-modified polysiloxane ( / g) at 130℃ for 2 hours. Cool down to 60℃, add 50 parts of the polyether-modified polysiloxane from Example 7, 30 parts of the mixture of Span 60 and Tween 60, 5 parts of hydroxypropyl cellulose, and 660 parts of deionized water, and mix evenly to obtain a hydroxyl-terminated polydimethylsiloxane-modified waterborne defoamer.

[0068] Comparative Example 3

[0069] Commercially available fluorinated water-based defoamers mainly consist of polydimethylsiloxane, polytrifluoropropylmethylsiloxane, silica, polyether-modified polysiloxane, and water.

[0070] Performance testing

[0071] (1) Conventional defoaming performance test: Take 50g of conventional foaming liquid (0.5%, surface tension ~34mN / m) and place it in a 100mL stoppered graduated cylinder. Shake the graduated cylinder 30 times to fill the graduated cylinder with foam. Add 1g of defoamer dilution (effective content 1%) and record the time t when the foam completely disappears.

[0072] (2) Defoaming performance test under harsh conditions: Take 90g of strong foaming liquid (0.4%, surface tension ~25mN / m) and place it in a 100mL stoppered graduated cylinder, add 0.8g of defoamer dilution (effective content 1%). Shake the graduated cylinder 30 times, let it stand for 1min and then calculate the foam volume V1.

[0073] (3) Defoaming performance test under extremely harsh conditions: Take 90g of strong foaming liquid (0.4%, surface tension ~25mN / m) and place it in a 100mL stoppered graduated cylinder, add 0.4g of defoamer dilution (effective content 1%). Shake the graduated cylinder 30 times, let it stand for 1min and then calculate the foam volume V2.

[0074]

[0075] The performance test results show that the defoamers prepared in the examples outperformed both the commercially available non-fluorinated aqueous defoamer (Comparative Example 1) and the hydroxyl-terminated polydimethylsiloxane-modified aqueous defoamer (Comparative Example 2). The defoaming performance of the defoamers prepared in the examples is similar to that of the commercially available polytrifluoropropylmethylsiloxane-modified aqueous defoamer (Comparative Example 3) under conventional defoaming conditions. Some examples showed better defoaming performance under harsh conditions than the commercially available polytrifluoropropylmethylsiloxane-modified aqueous defoamer (Comparative Example 3). All examples showed better defoaming performance under extremely harsh conditions than the commercially available polytrifluoropropylmethylsiloxane-modified aqueous defoamer (Comparative Example 3).

Claims

1. A waterborne organosilicon defoamer modified with hydroxyl fluorosilicone oil, comprising the following components in parts by weight: 5-50 parts polydimethylsiloxane, 0.1-5 parts hydroxyl fluorosilicone oil, 0.1-5 parts silica, 1-30 parts polyether-modified silicone oil, 1-30 parts emulsifier, 0-5 parts thickener, and 20-90 parts deionized water, wherein fluorine accounts for not less than 0.5 wt% of the total components excluding deionized water; The polyether-modified silicone oil is obtained by hydrosilylation of monoallyl-terminated polyether with hydrogen-containing silicone oil under the action of a platinum catalyst. The monoallyl-terminated polyether has the general structural formula as follows: CH2=CHCH2O(CH2CH2O) m (CH(CH3)CH20) n R, in, m is 2~20, n is 0~30, R is hydrogen or C1-C4 saturated alkyl group, and m and n are both positive integers.

2. The waterborne organosilicon defoamer modified with hydroxyl fluorosilicone oil according to claim 1, characterized in that: The hydroxyl fluorosilicone oil modified waterborne silicone defoamer comprises the following components in parts by weight: 5-40 parts of polydimethylsiloxane, 0.1-3 parts of hydroxyl fluorosilicone oil, 0.1-3 parts of silica, 2-15 parts of polyether modified silicone oil, 2-15 parts of emulsifier, 0-1 part of thickener, and 30-90 parts of deionized water.

3. A hydroxyl fluorosilicone oil-modified waterborne organosilicon defoamer according to claim 1 or 2, characterized in that: The viscosity of the polydimethylsiloxane is 300~2000 cP.

4. A hydroxyl fluorosilicone oil-modified waterborne organosilicon defoamer according to claim 1 or 2, characterized in that: The hydroxyl fluorosilicone oil is at least one of α,ω-dihydroxy polyfluorosiloxane obtained by ring-opening polymerization of fluorosilane cyclic compound and deionized water under the action of an acid catalyst, and α,ω-dihydroxy poly(fluorosiloxane-dimethylsiloxane) obtained by ring-opening copolymerization of fluorosilane cyclic compound, dimethylsiloxane cyclic compound and deionized water under the action of an acid catalyst.

5. The waterborne organosilicon defoamer modified with hydroxyl fluorosilicone oil according to claim 4, characterized in that: The fluorinated silane cyclic compound is either trifluoropropylmethylsiloxane cyclic compound or nonafluorohexylmethylsiloxane cyclic compound; the acid catalyst is a protic acid.

6. A hydroxyl fluorosilicone oil-modified waterborne organosilicon defoamer according to claim 1 or 2, characterized in that: The specific surface area of ​​the silica is not less than 160 m². 2 / g.

7. A hydroxyl fluorosilicone oil-modified waterborne organosilicon defoamer according to claim 1 or 2, characterized in that: The hydrogen content of the hydrogen-containing silicone oil is 0.05~0.4%.

8. A hydroxyl fluorosilicone oil-modified waterborne organosilicon defoamer according to claim 1 or 2, characterized in that: The platinum catalyst is either a cassiterite catalyst or a chloroplatinic acid catalyst.

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