Defoaming agent for oil paint and preparation method thereof

Abstract

The invention provides a defoaming agent for oil paint and a preparation method thereof, in particular to a fluorine-containing modified organic silicon defoaming agent, which is prepared by the following steps: stirring and mixing fluorine-modified silicone oil, methyl silicone oil and MQ resin, reacting with the MQ resin by using polyether amine as a dispersing agent, adding silyl ether, and carrying out heat preservation and rapid cooling processes. Polyether amine is used as a dispersing agent, the solubility of MQ resin in silicone oil can be improved, meanwhile, fluorine-modified silicone oil, the polyether amine dispersing agent and applicable silicon polyether of a full PO structure in a system all improve the foam eliminating and inhibiting performance, in addition, all the components are stirred and mixed and then subjected to a heat preservation reaction, and all the components are mixed more evenly, so that the effect is better achieved. The prepared defoaming agent has good defoaming and foam-inhibiting performance in the oil paint industry, meanwhile has the effects of being high in dispersity, improving the glossiness of a paint film and enabling the paint film to be fuller, and also has a good defoaming and foam-inhibiting effect on foam generated by other anion surface activity systems.

Description

Technical Field

[0001] The present invention relates to an antifoaming agent for oil-based coatings and a preparation method thereof, which is related to the preparation of fine chemical additives, and thus belongs to the technical field of fine chemical preparations. Background Art

[0002] In recent years, due to the country's emphasis on the environmental protection field, water-based coatings have gradually replaced traditional oil-based coatings, especially in the home decoration field. However, due to its unique properties such as waterproofing, anti-corrosion, wear resistance, and durability, oil-based coatings are still widely used, such as in construction, machinery manufacturing, railways, ships, aerospace, etc. In the construction field, oil-based coatings are widely used for waterproofing and moisture-proofing treatments on the exterior walls, roofs, and walls of buildings, and can also be used for fire protection treatments. The formed protective film can effectively prevent or delay the erosion of water, oxygen, etc. on building materials, thereby extending the service life of buildings. In addition, oil-based coatings can also be used in underground engineering, water conservancy projects and other fields.

[0003] The existing antifoaming agents on the market can be classified into mineral oil antifoaming agents, polyether antifoaming agents, silicone antifoaming agents, and polyacrylate antifoaming agents according to their components. Mineral oil antifoaming agents have good compatibility, large dosage tolerance, and are not prone to shrinkage holes; polyether antifoaming agents have outstanding foam suppression performance, but general defoaming power; silicone antifoaming agents have high defoaming efficiency, but poor foam suppression performance; polyacrylate antifoaming agents have relatively good defoaming power and compatibility, but their foam suppression performance is worse than that of polyether antifoaming agents.

[0004] In the prior art, there are few antifoaming agents that can balance these three properties of defoaming, foam suppression, and compatibility. In order to balance these characteristics, there are polyether-modified silicone antifoaming agents, fluorine-modified silicone antifoaming agents, and polyether-modified silicone antifoaming agents.

[0005] CN 107417847 A describes a fluorine-modified polyacrylate antifoaming agent and a preparation method thereof. The invention copolymerizes acrylate, methacrylate, and fluorine-containing methacrylate monomers, which can effectively reduce the surface tension and improve the defoaming effect of the antifoaming agent. Patent CN110960892A discloses a coating antifoaming agent, the main components of which are polyether silicone, silica, and alkylated oil, which improves the defoaming problem in high-viscosity coatings. However, silica is likely to form silica scale and silica spots in the coating; Patent CN106810934A discloses a thick-film coating antifoaming agent and a preparation method thereof. The antifoaming agent contains methyl silicone oil, higher fatty alcohol, and modified glycerol polyether. Pure silicone oil is difficult to emulsify in the system and is prone to demulsification. Moreover, the melting point of higher fatty alcohol is relatively high, and it is easy to crystallize and precipitate solids at low temperatures, resulting in difficult use. Summary of the Invention

[0006] The present invention provides a fluorine-modified silicone defoamer for the field of oil-based coatings. The fluorine-modified silicone oil, methyl silicone oil, and MQ resin are stirred and mixed. Using polyetheramine as a dispersant, it reacts with the MQ resin. After adding silicone ether, through a heat preservation and rapid cooling process, the defoamer is obtained. Using polyetheramine as a dispersant can increase the solubility of MQ resin in silicone oil. At the same time, the fluorine-modified silicone oil, polyetheramine dispersant, and applicable silicone polyether with a full PO structure in the system all improve the defoaming and foam suppression performance. In addition, after the components are stirred and mixed, a heat preservation reaction is carried out, making the components mix more evenly and thus better play their effects. The defoamer prepared by the present invention is mainly applied to the oil-based coating industry, has good defoaming and foam suppression performance, and at the same time has strong dispersibility, can improve the gloss of the paint film, and make the paint film more plump. It also has good defoaming and foam suppression effects on the foam generated by other anionic surfactant systems.

[0007] A. Fluorine-modified silicone oil

[0008] Preparation of fluorine-modified silicone oil: Add amino silicone oil, perfluoropropylene oxide, isopropyl alcohol, and catalyst KOH into a reaction flask, carry out a pressurized reaction for 3 - 12 h, neutralize the catalyst with glacial acetic acid, and remove the solvent by rotary evaporation to obtain fluorine-modified silicone oil.

[0009] The structural formula of the fluorine-modified silicone oil is as follows:

[0010]

[0011] Among them, R is -CH3 or -H; R2 is CH2CH2CH2NHCH2CH2NHCF2CF(CF3)O-[CF2CF(CF3)O] q -H;

[0012] m = 10 - 500, n = 1 - 100, p = 1 - 100, q = 2 - 6. The dosage of the fluorine-modified silicone oil is 1 - 8% of the total mass of the defoamer.

[0013] B. Methyl silicone oil

[0014] The methyl silicone oil generally selects methyl silicone oil with a dynamic viscosity of 100 - 1000 mPa·s at 25°C, and the dosage of the methyl silicone oil is 5 - 15% of the total mass of the defoamer.

[0015] C. Silicone polyether

[0016] The general structural formula of the silicone polyether in the present invention is as follows:

[0017]

[0018] In the formula, Me is methyl, x and y are degrees of polymerization, x is an integer from 1 to 100, and y is an integer from 1 to 50; P is selected from methyl and polyether groups, and at least one P is a polyether group. The general structural formula of the polyether group is as follows:

[0019] -CH2CH2CH2(OCH2CHCH3) d OH

[0020] In the general structural formula, d is the degree of polymerization, which is an integer from 10 to 50. The dosage of the silicone polyether accounts for 2% to 9% of the total mass of the defoamer.

[0021] D. MQ silicone resin

[0022] The MQ silicone resin refers to a silicone resin composed of the chain unit CH3SiO l / 2 (M unit) and the chain unit SiO 4 / 2 (Q unit), and the molar ratio between the two is 0.4:1.0 to 1.2:1.0, preferably 0.5:1.0 to 0.8:1.0. The dosage of the MQ silicone resin is 2% to 10% of the total mass of the defoamer.

[0023] E. Dispersant

[0024] The dispersant is a polyetheramine dispersant, and the structural formula is as follows

[0025] R’-[OCH2CH2] a -[OCH2CH(CH3)] b -NH2

[0026] Wherein R’ is selected from -H or -CH3, a ranges from 0 to 5, and b ranges from 9 to 30; the dosage of the dispersant is 0.5% to 3.5% of the total mass of the defoamer.

[0027] F. Organic solvent

[0028] The organic solvent is selected from ethylene glycol, tripropylene glycol butyl ether, dipropylene glycol butyl ether, propylene glycol butyl ether, tripropylene glycol methyl ether, dipropylene glycol methyl ether, dipropylene glycol propyl ether, ethylene glycol hexyl ether, diethylene glycol hexyl ether, diethylene glycol butyl ether, ethylene glycol butyl ether, 1,4-butanediol monomethyl ether. The dosage of the organic solvent is 60% to 85% of the total mass of the defoamer.

[0029] A preparation method of a defoamer for oil-based coatings is as follows:

[0030] 1) Put the fluorine-modified silicone oil, methyl silicone oil and MQ resin into a reaction vessel, start stirring and heat up to 50 - 120 °C, add the dispersant, continue stirring, and keep warm for 0.5 - 2 h after fully mixing;

[0031] 2) After the heat preservation ends, slowly add the silicone polyether and continue to keep warm for 1 - 2 h;

[0032] 3) After the heat preservation is completed, quickly cool down to 20 - 30 °C, and control the cooling time within 5 - 8 min;

[0033] 4) After cooling, add the remaining solvent, and stir and mix for 1 - 2 h to obtain the defoamer. Specific embodiments

[0034] Example of component A fluorine - modified silicone oil:

[0035]

[0036] Example of component C silicone polyether:

[0037]

[0038] Example 1

[0039] 1) Put 7.5 parts of fluorine - modified silicone oil A1, 15 parts of methyl silicone oil with a viscosity of 200 mPa·s and 5 parts of MQ resin with a molar ratio of M:Q = 0.4:1.0 into a reaction vessel, start stirring and heat up to 60 °C, add 3.5 parts of polyetheramine dispersant H - [OCH2CH(CH3)] 30 -NH2, continue stirring, and after making them fully mixed, keep warm for 0.5 h;

[0040] 2) After the heat preservation is completed, slowly add 9 parts of silicone polyether C1, and continue to keep warm for 1 h;

[0041] 3) After the heat preservation is completed, quickly cool down to 25 °C, and control the cooling time within 5 min;

[0042] 4) After cooling, add 60 parts of the solvent diethylene glycol butyl ether, and stir and mix for 2 h to obtain the defoamer.

[0043] Example 2

[0044] 1) Put 5.5 parts of fluorine - modified silicone oil A2, 6 parts of methyl silicone oil with a viscosity of 100 mPa·s and 8 parts of MQ resin with a molar ratio of M:Q = 0.8:1.0 into a reaction vessel, start stirring and heat up to 50 °C, add 2.5 parts of polyetheramine dispersant CH3 - [OCH2CH2]5 - [OCH2CH(CH3)] 15 -NH2, continue stirring, and after making them fully mixed, keep warm for 0.5 h;

[0045] 2) After the heat preservation is completed, slowly add 8 parts of silicone polyether C2, and continue to keep warm for 1 h;

[0046] 3) After the heat preservation is completed, quickly cool down to 30 °C, and control the cooling time within 5 min;

[0047] 4) After cooling, add 70 parts of the solvent tripropylene glycol methyl ether and stir and mix for 0.5 h to obtain the defoamer.

[0048] Example 3

[0049] 1) Put 8 parts of fluorine-modified silicone oil A3, 10 parts of methyl silicone oil with a viscosity of 500 mPa·s and 10 parts of MQ resin with a molar ratio of M:Q = 0.8:1.0 into a reaction vessel, start stirring and heat up to 80 °C, and add 3 parts of polyetheramine dispersant H-[OCH2CH2]4-[OCH2CH(CH3)] 22 -NH2, continue stirring, and keep warm for 1 h after fully mixing;

[0050] 2) After the heat preservation is over, slowly add 4 parts of silicone polyether C3 and continue to keep warm for 2 h;

[0051] 3) After the heat preservation is over, quickly cool down to 20 °C, and control the cooling time within 6 min;

[0052] 4) After cooling, add 65 parts of the solvent ethylene glycol and stir and mix for 1 h to obtain the defoamer.

[0053] Example 4

[0054] 1) Put 4.5 parts of fluorine-modified silicone oil A4, 8 parts of methyl silicone oil with a viscosity of 800 mPa·s and 2 parts of MQ resin with a molar ratio of M:Q = 1.2:1.0 into a reaction vessel, start stirring and heat up to 100 °C, and add 0.5 part of polyetheramine dispersant CH3-[OCH2CH2]2-[OCH2CH(CH3)]9-NH2, continue stirring, and keep warm for 2 h after fully mixing;

[0055] 2) After the heat preservation is over, slowly add 5 parts of silicone polyether C4 and continue to keep warm for 2 h;

[0056] 3) After the heat preservation is over, quickly cool down to 25 °C, and control the cooling time within 7 min;

[0057] 4) After cooling, add 80 parts of the solvent 1,4-butanediol monomethyl ether and stir and mix for 1.5 h to obtain the defoamer.

[0058] Example 5

[0059] 1) Put 1 part of fluorine-modified silicone oil A5, 5 parts of methyl silicone oil with a viscosity of 1000 mPa·s and 6 parts of MQ resin with a molar ratio of M:Q = 1.0:1.0 into a reaction vessel, start stirring and heat up to 120 °C, and add 1 part of polyetheramine dispersant CH3-[OCH2CH2]3-[OCH2CH(CH3)] 12 -NH2, continue stirring, and keep warm for 1 h after fully mixing;

[0060] 2) After the heat preservation is completed, slowly add 2 parts of silicone polyether C5 and continue heat preservation for 2 h;

[0061] 3) After the heat preservation is completed, quickly cool down to 30 °C, and control the cooling time within 8 min;

[0062] 4) After cooling, add 85 parts of the solvent ethylene glycol hexyl ether and stir and mix for 1 h to obtain the defoamer.

[0063] Example 6

[0064] 1) Put 1.5 parts of fluorine-modified silicone oil A6, 12 parts of methyl silicone oil with a viscosity of 500 mPa·s and 4 parts of MQ resin with a molar ratio of M:Q = 0.5:1.0 into a reaction vessel, start stirring and heat up to 80 °C, and add 1.5 parts of polyetheramine dispersant H-[OCH2CH2]-[OCH2CH(CH3)] 25 -NH2, continue stirring, and after sufficient mixing, keep warm for 1 h;

[0065] 2) After the heat preservation is completed, slowly add 6 parts of silicone polyether C6 and continue heat preservation for 1 h;

[0066] 3) After the heat preservation is completed, quickly cool down to 20 °C, and control the cooling time within 6 min;

[0067] 4) After cooling, add 75 parts of the solvent dipropylene glycol propyl ether and stir and mix for 2 h to obtain the defoamer.

[0068] Comparative Example 1

[0069] 1) Put 7.5 parts of polyether-modified silicone oil, 15 parts of methyl silicone oil with a viscosity of 200 mPa·s and 5 parts of MQ resin with a molar ratio of M:Q = 0.4:1.0 into a reaction vessel, start stirring and heat up to 60 °C, and add 3.5 parts of polyetheramine dispersant H-[OCH2CH(CH3)] 30 -NH2, continue stirring, and after sufficient mixing, keep warm for 0.5 h;

[0070] 2) After the heat preservation is completed, slowly add 9 parts of silicone polyether C1 and continue heat preservation for 1 h;

[0071] 3) After the heat preservation is completed, quickly cool down to 25 °C, and control the cooling time within 5 min;

[0072] 4) After cooling, add 60 parts of the solvent diethylene glycol butyl ether and stir and mix for 2 h to obtain the defoamer.

[0073] Comparative Example 2

[0074] 1) Put 5.5 parts of fluorine-modified silicone oil A2, 6 parts of methyl silicone oil with a viscosity of 100 mPa·s, and 8 parts of MQ resin with a molar ratio of M:Q = 0.8:1.0 into a reaction vessel. Start stirring and heat up to 50 °C. Add 2.5 parts of the dispersant dodecyl dimethyl betaine, continue stirring, and keep it warm for 0.5 h after thorough mixing;

[0075] 2) After the heat preservation ends, slowly add 8 parts of silicone polyether C2 and continue to keep it warm for 1 h;

[0076] 3) After the heat preservation ends, quickly cool down to 30 °C, and control the cooling time within 5 min;

[0077] 4) After cooling, add 70 parts of the solvent tripropylene glycol methyl ether and stir and mix for 0.5 h to obtain the defoamer.

[0078] Comparative Example 3

[0079] 1) Put 8 parts of fluorine-modified silicone oil A3, 10 parts of methyl silicone oil with a viscosity of 500 mPa·s, and 10 parts of MQ resin with a molar ratio of M:Q = 0.8:1.0 into a reaction vessel. Start stirring and heat up to 80 °C. Add 3 parts of the polyetheramine dispersant H-[OCH2CH2] 10 -[OCH2CH(CH3)] 40 -NH2, continue stirring, and keep it warm for 1 h after thorough mixing;

[0080] 2) After the heat preservation ends, slowly add 4 parts of silicone polyether C3 and continue to keep it warm for 2 h;

[0081] 3) After the heat preservation ends, quickly cool down to 20 °C, and control the cooling time within 6 min;

[0082] 4) After cooling, add 65 parts of the solvent ethylene glycol and stir and mix for 1 h to obtain the defoamer.

[0083] Comparative Example 4

[0084] 1) Put 4.5 parts of fluorine-modified silicone oil A4, 8 parts of methyl silicone oil with a viscosity of 800 mPa·s, and 2 parts of MQ resin with a molar ratio of M:Q = 1.2:1.0 into a reaction vessel. Start stirring and heat up to 100 °C. Add 0.5 parts of the polyetheramine dispersant CH3-[OCH2CH2]2-[OCH2CH(CH3)]9-NH2, continue stirring, and keep it warm for 2 h after thorough mixing;

[0085] 2) After the heat preservation ends, slowly add 5 parts of silicone polyether R1O(EO) x (PO) y R2 (R1 = CH3(CH2) 17 -, R2 = CH3(CH2) 10CO-, x = 20, y = 50), keep warm for another 2 h;

[0086] 3) After the heat preservation ends, quickly cool down to 25 °C, and control the cooling time within 7 min;

[0087] 4) After cooling, add 80 parts of solvent 1,4-butanediol monomethyl ether, and stir and mix for 1.5 h to obtain the defoamer.

[0088] Comparative Example 5

[0089] 1) Put 1 part of fluorine-modified silicone oil A5, 5 parts of methyl silicone oil with a viscosity of 5000 mPa·s and 6 parts of MQ resin with a molar ratio of M:Q = 1.0:1.0 into a reaction vessel, start stirring and heat up to 120 °C, and add 1 part of polyetheramine dispersant CH3-[OCH2CH2]3-[OCH2CH(CH3)] 12 -NH2, continue stirring, and after making them fully mixed, keep warm for 1 h;

[0090] 2) After the heat preservation ends, slowly add 2 parts of silicone polyether C5, and continue to keep warm for 2 h;

[0091] 3) After the heat preservation ends, quickly cool down to 30 °C, and control the cooling time within 8 min;

[0092] 4) After cooling, add 85 parts of solvent ethylene glycol hexyl ether, and stir and mix for 1 h to obtain the defoamer.

[0093] Comparative Example 6

[0094] 1) Put 1.5 parts of fluorine-modified silicone oil A6, 12 parts of methyl silicone oil with a viscosity of 500 mPa·s and 4 parts of MQ resin with a molar ratio of M:Q = 0.5:1.0 into a reaction vessel, start stirring and heat up to 80 °C, and add 1.5 parts of polyetheramine dispersant H-[OCH2CH2]-[OCH2CH(CH3)] 25 -NH2, continue stirring, and after making them fully mixed, slowly add 6 parts of silicone polyether C6, stir and mix evenly, and then quickly cool down to 20 °C, and control the cooling time within 6 min;

[0095] 2) After cooling, add 75 parts of solvent dipropylene glycol propyl ether, and stir and mix for 2 h to obtain the defoamer.

[0096] Performance Test

[0097] Defoaming and foam suppression performance test:

[0098] High-speed dispersion test method: Add 200 ml of the prepared coating into a 1000-ml cup, then add 0.3% defoamer. Use a laboratory high-speed disperser to disperse at a speed of 1000 rpm for 10 minutes. Immediately pour it into a 1000-ml graduated cylinder after stopping. Record the weight and volume of the liquid, calculate the specific gravity. A larger specific gravity value indicates less gas content, showing good defoaming and foam suppression performance of the defoamer. The test results are as follows:

[0099]

Claims

1. A defoamer for oily paint, characterized in that: The defoamer comprises the following components: A. Fluorinated modified silicone oil Preparation of fluorine-containing modified silicone oil: amino silicone oil, perfluoropropylene oxide, isopropanol and catalyst KOH are added to a reaction bottle, reacted under pressure for 3 to 12 hours, the catalyst is neutralized with glacial acetic acid, and the solvent is removed by rotary evaporation to obtain fluorine-containing modified silicone oil; the amount of the fluorine-containing modified silicone oil is 1 to 8% of the total mass of the defoamer; B. Methyl silicone oil The dosage of methyl silicone oil is 5-15% of the total mass of the defoamer; C. Silicone polyether The amount of silicone polyether used accounts for 2-9% of the total mass of the defoamer; D.MQ Silicone Resin The dosage of MQ silicone resin is 2-10% of the total mass of the defoamer; E. Dispersant The amount of dispersant used is 0.5-3.5% of the total mass of the defoamer; F. Organic solvents The amount of organic solvent used is 60-85% of the total mass of the defoamer; The defoamer for oily paint is prepared by the following method: 1) Put fluorine-modified silicone oil, methyl silicone oil and MQ resin into a reaction vessel, start stirring and heat to 50-120°C, add dispersant, continue stirring, mix thoroughly, and keep warm for 0.5-2h; 2) After the heat preservation is completed, slowly add silicone polyether and continue to keep warm for 1 to 2 hours; 3) After the insulation is completed, the temperature is quickly lowered to 20-30°C, and the cooling time is controlled within 5-8 minutes; 4) After cooling, the remaining solvent is added, and the mixture is stirred for 1 to 2 hours to obtain the defoaming agent.

2. A defoamer for oily paint according to claim 1, characterized in that: The structural formula of the fluorine-containing modified silicone oil is as follows: Wherein, R is -CH3 or -H; R2 is CH2CH2CH2NHCH2CH2NHCF2CF(CF3)O-[CF2CF(CF3)O] q -H; m=10~500, n=1~100, p=1~100, q=2~6.

3. A defoamer for oily paint according to claim 1, characterized in that: The methyl silicone oil is generally selected from methyl silicone oils having a dynamic viscosity of 100 to 1000 mPa·s at 25°C.

4. A defoamer for oily paint according to claim 1, characterized in that: The general structure of the silicon polyether is as follows: In the formula, Me is a methyl group, x and y are the degree of polymerization, x is an integer of 1 to 100, and y is an integer of 1 to 50; P is selected from a methyl group and a polyether group, and at least one P is a polyether group, wherein the general structural formula of the polyether group is as follows: -CH2CH2CH2(OCH2CHCH3) d OH In the general structural formula, d is the degree of polymerization, which is an integer of 10-50.

5. A defoamer for oily paint according to claim 1, characterized in that: The MQ silicone resin is composed of CH3SiO l / 2 (M unit) and chain SiO 4 / 2 (Q unit) composed of silicone resin.

6. A defoamer for oily paint according to claim 1, characterized in that: The dispersant is a polyetheramine dispersant, and the structural formula is as follows R'-[OCH2CH2] a -[OCH2CH(CH3)] b -NH2 Wherein R' is selected from -H or -CH3, a is 0-5, and b is 9-30.

7. A defoamer for oily paint according to claim 1, characterized in that: The organic solvent is selected from ethylene glycol, tripropylene glycol butyl ether, dipropylene glycol butyl ether, propylene glycol butyl ether, tripropylene glycol methyl ether, dipropylene glycol methyl ether, dipropylene glycol propyl ether, ethylene glycol hexyl ether, diethylene glycol hexyl ether, diethylene glycol butyl ether, ethylene glycol butyl ether, and 1,4-butanediol monomethyl ether.

8. A defoamer for oily paint according to claim 1, characterized in that: The molar ratio of the M unit to the Q unit of the MQ silicone resin is 0.4:1.0 to 1.2:1.0.

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