A ternary copolymer type defoamer and its preparation method

Abstract

The invention discloses a ternary copolymer defoamer and a preparation method thereof. The preparation steps adopted by the invention are as follows: step 1), placing hydrogen-containing silicone oil, alkynol and allyl polyether in a reaction kettle, heating the temperature to 85-95°C for the first time, evacuating the reaction kettle to a negative pressure of ≤-0.09 MPa, evacuating the reaction kettle for 25-35 minutes, and stopping; placing nitrogen gas, adding a catalyst, heating the reaction kettle to 120-135°C for the second time, keeping the temperature for 3-6 hours, and cooling the reaction kettle to obtain a ternary copolymer; step 2), mixing the ternary copolymer, polyether, a solvent and an emulsifier, heating and stirring the mixture to obtain the ternary copolymer defoamer; the alkynol has a carbon chain number of 6-12 and a hydroxyl number of 4-8. The present invention ternary copolymerizes a small molecule alkynol segment, a large molecule organic silicone oil segment and a polyether segment, and combines the respective advantages of the small molecule alkynol, silicone oil and polyether to solve the three problems of defoaming, foam suppression and compatibility of defoamers in water-based paints and water-based ink systems. It also solves the problems of pinholes, fish eyes and semi-transparency caused by foam in the spray printing process.

Description

Technical Field

[0001] The invention belongs to the field of fine chemicals and relates to a defoamer, in particular to a ternary copolymer defoamer and a preparation method thereof. Background Art

[0002] Water-based paints and inks generate foam during production and use, severely impacting spraying and brushing performance. Alkynol defoamers are small molecule defoamers with excellent surface spreading, instantly eliminating surface foam generated by water-based paints and inks. More importantly, the hydroxyl groups in alkynols can hydrogen bond with the hydroxyl and carboxyl groups in the adhesives used in water-based paints and inks, enhancing their compatibility with the paints and inks and improving their compatibility with the paints and inks. As a result, they exhibit excellent compatibility with water-based paints and inks, but their defoaming properties gradually diminish, making subsequent foaming difficult to eliminate. Adhesives used in water-based paints and inks are high-molecular-weight surfactants, which generate highly viscous and elastic foams. While alkynol defoamers are effective at eliminating low-viscosity, low-elasticity foams, they are less effective at eliminating high-viscosity, high-elasticity foams.

[0003] Silicones have extremely low surface tension and strong bubble-breaking capabilities, effectively eliminating high-viscosity, highly elastic foam generated in inks and coatings. However, due to their long chain length and high lipophilicity, silicones have poor compatibility with ink and coating systems, easily causing problems such as silicon spots and translucency, which in turn lead to cratering in spray printing. Furthermore, as water-based paints and inks are stored for extended periods, the defoamer in the system loses effectiveness, resulting in poor subsequent foam suppression. This prolonged storage can lead to secondary foam recurrence during use, causing problems such as pinholes and translucency. Summary of the Invention

[0004] In order to solve the defects in the above-mentioned prior art, the present invention provides a ternary copolymer defoamer and a preparation method thereof, so as to solve the three problems of defoaming, foam suppression and compatibility of the defoamer in water-based paint and water-based ink systems.

[0005] To this end, the present invention is achieved through the following technical solutions:

[0006] A method for preparing a ternary copolymer defoamer, comprising:

[0007] Step 1) placing hydrogenated silicone oil, acetylene alcohol and allyl polyether in a reaction kettle, heating to 85-95°C for the first time, evacuating to a negative pressure of ≤-0.09 MPa, evacuating for 25-35 minutes, and then stopping; placing nitrogen, adding a catalyst, heating to 120-135°C for the second time, keeping the temperature for 3-6 hours, and cooling to obtain a terpolymer;

[0008] Step 2) mixing the terpolymer, polyether, solvent and emulsifier, heating and stirring to obtain a ternary copolymer defoamer;

[0009] The carbon chain number of the alkynol is 6-12, and the hydroxyl number is 4-8.

[0010] The preparation method of the present invention is simple, has a short reaction cycle, and is easy to operate. The first heating and holding step is to remove low-volatility impurities from the raw materials, and nitrogen is used to prevent oxidation reactions caused by air contact, which could reduce conversion. The second, incremental heating step is intended to prevent implosion and excessive crosslinking. The temperature is then raised in steps to the desired final temperature and then held.

[0011] The main reaction equation of the terpolymer (intermediate A) of the present invention is:

[0012]

[0013] Hydrogenated silicone oil, acetylenic alcohol, and allyl polyether undergo hydrosilylation, breaking the double bond of the allyl polyether and forming a chemical bond with the Si atom on one side of the carbon chain to form silicone oil and polyether segments. The carbon-carbon triple bond in the acetylenic alcohol is broken to form a bidirectional Si-C bond. Finally, with the acetylenic alcohol segment as the center, silicone oil is grafted onto acetylenic alcohol, and polyether is grafted onto silicone oil, forming a ternary copolymer. This ternary copolymer contains hydrophilic -OH and EO segments, and hydrophobic silicone oil and PO segments.

[0014] Water-based paints contain adhesives, which are a type of high-molecular surfactant. The foams caused by them have high viscosity and high elasticity. Alkyl alcohol defoamers have certain advantages in eliminating low-viscosity and low-elasticity foams, but they cannot completely eliminate high-viscosity and high-elasticity foams. Silicones have extremely low surface tension and strong bubble-breaking ability, and can effectively eliminate high-viscosity and high-elasticity foams generated in water-based paints and water-based inks, but their persistence is poor and the anti-foaming effect is not good. Not only that, the silicone chain is long and lipophilic, and its compatibility in water-based paint systems is poor, which can easily cause problems such as silicon spots and semi-permeability.

[0015] Alkynols are small molecule defoamers with excellent surface spreading ability, instantly eliminating foam generated on the surface of water-based paints and inks. More importantly, the hydroxyl groups in alkynols can hydrogen bond with the hydroxyl and carboxyl groups in adhesives used in water-based paints and inks, enhancing their compatibility with these adhesives and improving their compatibility with these materials. Furthermore, conventional dihydroxyl alkynols exhibit poor compatibility with water-based paints and inks with high carboxyl content. However, increasing the hydroxyl content of the alkynol to 4, 6, or 8, allows the multiple hydroxyl groups in the alkynol to form bonds with the acetylenic bonds. These bonds create a synergistic effect, significantly increasing their hydrophilicity and enhancing their binding to the carboxyl groups in water-based paints and inks. Furthermore, as the carboxyl group ratio in water-based paints and inks increases, the bonds between the polyhydroxyl alkynol components and the carboxyl groups become more stable, leading to enhanced compatibility of the polyhydroxyl alkynols in water-based paint systems with high carboxyl content.

[0016] Polyethers disperse well in aqueous systems, especially above the cloud point. Polyether molecules remain free in water, providing excellent anti-foaming properties that do not degrade over time. Depending on the EO and PO ratios, polyethers generally maintain a sustained anti-foaming effect below 85°C. In the production and use of water-based paints and inks, polyethers offer a wider temperature range for anti-foaming.

[0017] The copolymerization of hydrogen-containing silicone oil, acetylene alcohol with high hydroxyl content and allyl polyether (methyl end-capping, random mixture of ethyl epoxide and propyl epoxide) combines the advantages of the three, combining the rapid surface spreading ability (rapid dispersibility) and system compatibility of acetylene alcohol with the good foam breaking ability of silicone and the foam suppression effect of polyether in a wide temperature range, to obtain a ternary copolymer defoamer suitable for water-based paint and water-based ink systems.

[0018] Furthermore, the hydrogen-containing silicone oil is end-containing hydrogen-containing silicone oil, side-containing hydrogen-containing silicone oil or end-side-containing hydrogen-containing silicone oil, the hydrogen content is 0.1-0.5%, and the molar ratio of hydrogen-containing silicone oil, acetylenic alcohol and allyl polyether is 1:(0.25-1.5):(0.5-2.5).

[0019] Furthermore, the allyl polyether has a molecular weight of 450-2000, EO:PO=1:0.2-5, is methyl-terminated, and is a random mixture of ethyl epoxide and propyl epoxide.

[0020] Furthermore, in step 2), the mixture is heated to 35-55° C. and stirred for 1-2 hours to obtain a ternary copolymer defoaming agent.

[0021] Furthermore, the catalyst is chloroplatinic acid, and the dosage is 10-25 ppm.

[0022] Furthermore, the polyether is one or a mixture of monofunctional, difunctional, and trifunctional polyoxyethylene polyoxypropylene ethers.

[0023] Furthermore, the solvent is one or a mixture of castor oil, oleic acid, olein, stearin, and pentaerythritol stearate.

[0024] Furthermore, the emulsifier is one or a mixture of oleic acid polyoxyethylene ether, fatty alcohol polyoxyethylene ether, castor oil polyoxyethylene ether, and PEG200-800.

[0025] Furthermore, the mass fractions of the mixture used in step 2) are: 50-70% of terpolymer, 15-25% of polyether, 10-20% of solvent, and 5-10% of emulsifier.

[0026] The present invention also provides a ternary copolymer defoaming agent prepared by the above preparation method.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1. The present invention synthesizes a ternary copolymer of organosilicon, acetylene alcohol and allyl polyether as a defoamer intermediate, and prepares a ternary copolymer defoamer by designing an emulsification formula.

[0029] 2. Alkynols are small-molecule defoamers with fast surface spreading, dispersion, and defoaming, and they exhibit good compatibility in water-based paints and inks. In particular, polyhydroxyl-containing alkynols bond more firmly with the carboxyl groups in water-based paints, resulting in improved compatibility in water-based paint systems with high carboxyl groups. Silicone oils have very low surface tension and excellent defoaming properties, and are particularly effective in eliminating highly elastic, high-viscosity foams generated by polymer emulsion systems. Polyethers, obtained through the copolymerization of EO and PO, exhibit excellent foam suppression over a wide temperature range, extending the antifoaming effect of water-based paints and inks during use. The ternary copolymerization of a small-molecule alkynol segment with a large-molecule organosilicon segment and a polyether segment combines the respective advantages of small-molecule alkynols, silicone oils, and polyethers, solving the defoaming, foam suppression, and compatibility issues of defoamers in water-based paints and inks. It also addresses the pinhole, fisheye, and translucency problems caused by foam during the spray printing process.

[0030] 3. The defoamer prepared according to the present invention has low surface tension, good chemical stability, and is resistant to acid, alkali and high temperature systems.

[0031] 4. It is used in water-based paint and water-based ink systems with little negative impact on them. It has the characteristics of small dosage, fast defoaming speed, strong anti-foaming ability, non-toxic and harmless, and simple process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a comparison chart of the antifoaming effects of different defoamers in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0033] The invention will be further described in detail below with reference to the embodiments, but they are not intended to limit the invention in any way.

[0034] Example 1

[0035] 1) Hydrogenated silicone oil (0.1% hydrogen content), alkynol (carbon chain number 6, number of hydroxyl groups 4) and allyl polyether (M = 450, EO:PO = 1:0.2) were placed in a reaction kettle at a molar ratio of 1:0.25:0.5, the temperature was raised to 85°C for the first time, and vacuumed to -0.095 MPa for 30 minutes, then stopped, replaced with nitrogen, and 10 ppm (total amount of the system) of catalyst chloroplatinic acid was added. The temperature was raised to 135°C for the second time, maintained at this temperature for 3 hours, and then cooled to obtain terpolymer A;

[0036] 2) 50 g of terpolymer A, 25 g of fatty alcohol polyoxyethylene polyoxypropylene ether, 20 g of castor oil, and 5 g of castor oil polyoxyethylene ether were mixed, heated to 35° C., and stirred for 2 h to obtain terpolymer defoamer B.

[0037] Test method:

[0038] Defoaming test: (Density method) Use styrene butadiene latex as the foaming system, take 200g of styrene butadiene latex, place it in a 500g cup, add 0.2g of defoamer, start stirring, 1200r / min, stir for 3 minutes, then quickly transfer the styrene butadiene latex to two 100ml buckets. When the liquid level (including foam) reaches 100ml, weigh it and record the data to obtain the density.

[0039] Foam suppression (air bubbling method): Take 300g of styrene-butadiene latex, add 0.2g of nonylphenol polyoxyethylene ether 10EO + 0.2g of sodium dodecylbenzene sulfonate, place in a 1000ml graduated cylinder, set the air flow to 2L / min, start bubbling, and record the foam volume per minute.

[0040] Compatibility: Take 200g of paint, add 0.2g of defoamer, stir evenly, and apply evenly on a clean and transparent glass plate. Observe the shrinkage cavities and make a record.

[0041] Example 2

[0042] 1) Hydrogenated silicone oil (0.5% hydrogen content), alkynol (carbon chain number 12, number of hydroxyl groups 6) and allyl polyether (M = 2000, EO:PO = 1:5) were placed in a reaction kettle at a molar ratio of 1:1.5:2.5, the temperature was raised to 95°C for the first time, and vacuumed to -0.095 MPa for 30 minutes, then stopped, replaced with nitrogen, and 25 ppm (total amount of the system) of catalyst chloroplatinic acid was added. The temperature was raised to 120°C for the second time, maintained for 6 hours, and cooled to obtain terpolymer A;

[0043] 2) 70 g of terpolymer A, 15 g of propylene glycol polyoxyethylene polyoxypropylene ether, 10 g of oleic acid glyceride, and 5 g of oleic acid polyoxyethylene ether were mixed, heated to 55° C., and stirred for 1 h to obtain ternary copolymer defoamer B.

[0044] Test method:

[0045] Defoaming test: (Density method) Use styrene butadiene latex as the foaming system, take 200g of styrene butadiene latex, place it in a 500g cup, add 0.2g of defoamer, start stirring, 1200r / min, stir for 3 minutes, then quickly transfer the styrene butadiene latex to two 100ml buckets. When the liquid level (including foam) reaches 100ml, weigh it and record the data to obtain the density.

[0046] Foam suppression (air bubbling method): Take 300g of styrene-butadiene latex, add 0.2g of nonylphenol polyoxyethylene ether 10EO + 0.2g of sodium dodecylbenzene sulfonate, place in a 1000ml graduated cylinder, set the air flow to 2L / min, start bubbling, and record the foam volume per minute.

[0047] Compatibility: Take 200g of paint, add 0.2g of defoamer, stir evenly, and apply evenly on a clean and transparent glass plate. Observe the shrinkage cavities and make a record.

[0048] Example 3

[0049] 1) Hydrogenated silicone oil (0.25% hydrogen content), alkynol (carbon chain number 10, number of hydroxyl groups 8) and allyl polyether (M = 1000, EO:PO = 1:2) were placed in a reaction kettle at a molar ratio of 1:1:1.5, the temperature was raised to 90°C for the first time, and vacuumed to -0.095 MPa for 30 minutes, then stopped, replaced with nitrogen, and 15 ppm (total amount of the system) of catalyst chloroplatinic acid was added. The temperature was raised to 130°C for the second time, maintained at this temperature for 5 hours, and then cooled to obtain terpolymer A;

[0050] 2) 55 g of terpolymer A, 20 g of glycerol polyoxyethylene polyoxypropylene ether, 15 g of glyceryl stearate, and 10 g of fatty alcohol polyoxyethylene ether were mixed, heated to 55° C., and stirred for 1.5 h to obtain ternary copolymer defoamer B.

[0051] Test method:

[0052] Defoaming test: (Density method) Use styrene butadiene latex as the foaming system, take 200g of styrene butadiene latex, place it in a 500g cup, add 0.2g of defoamer, start stirring, 1200r / min, stir for 3 minutes, then quickly transfer the styrene butadiene latex to two 100ml buckets. When the liquid level (including foam) reaches 100ml, weigh it and record the data to obtain the density.

[0053] Foam suppression (air bubbling method): Take 300g of styrene-butadiene latex, add 0.2g of nonylphenol polyoxyethylene ether 10EO + 0.2g of sodium dodecylbenzene sulfonate, place in a 1000ml graduated cylinder, set the air flow to 2L / min, start bubbling, and record the foam volume per minute.

[0054] Compatibility: Take 200g of paint, add 0.2g of defoamer, stir evenly, and apply evenly on a clean and transparent glass plate. Observe the shrinkage cavities and make a record.

[0055] Example 4

[0056] 1) Hydrogenated silicone oil (0.25% hydrogen content), alkynol (carbon chain number 10, number of hydroxyl groups 8) and allyl polyether (M = 1000, EO:PO = 1:2) were placed in a reaction kettle at a molar ratio of 1:1:1.5, the temperature was raised to 90°C for the first time, and vacuumed to -0.095 MPa for 30 minutes, then stopped, replaced with nitrogen, and 15 ppm (total amount of the system) of catalyst chloroplatinic acid was added. The temperature was raised to 130°C for the second time, maintained at this temperature for 5 hours, and then cooled to obtain terpolymer A;

[0057] 2) 55 g of terpolymer A, 20 g of glycerol polyoxyethylene polyoxypropylene ether, 15 g of oleic acid / stearate pentaerythritol ester (mass ratio 1:1), and 10 g of PEG200 / PEG800 (mass ratio 1:1) were mixed, heated to 55° C., and stirred for 1.5 h to obtain ternary copolymer defoamer B.

[0058] Test method:

[0059] Defoaming test: (Density method) Use styrene butadiene latex as the foaming system, take 200g of styrene butadiene latex, place it in a 500g cup, add 0.2g of defoamer, start stirring, 1200r / min, stir for 3 minutes, then quickly transfer the styrene butadiene latex to two 100ml buckets. When the liquid level (including foam) reaches 100ml, weigh it and record the data to obtain the density.

[0060] Foam suppression (air bubbling method): Take 300g of styrene-butadiene latex, add 0.2g of nonylphenol polyoxyethylene ether 10EO + 0.2g of sodium dodecylbenzene sulfonate, place in a 1000ml graduated cylinder, set the air flow to 2L / min, start bubbling, and record the foam volume per minute.

[0061] Compatibility: Take 200g of paint, add 0.2g of defoamer, stir evenly, and apply evenly on a clean and transparent glass plate. Observe the shrinkage cavities and make a record.

[0062] Comparative Example

[0063] Hydrogenated silicone oil (0.1% hydrogen content), acetylene glycol (number of hydroxyl groups: 2) and allyl polyether (M=450, EO:PO=1:0.2) were placed in a reaction kettle at a molar ratio of 1:0.25:0.5. The reaction mixture was heated to 85°C for the first time and vacuumed to -0.095 MPa for 30 min. The reaction mixture was stopped and replaced with nitrogen. 10 ppm (total amount of the system) of catalyst chloroplatinic acid was added. The reaction mixture was heated to 135°C for the second time and kept at this temperature for 3 h. The reaction mixture was then cooled to obtain terpolymer A.

[0064] Mix 50 g of terpolymer A, 25 g of fatty alcohol polyoxyethylene polyoxypropylene ether, 20 g of castor oil, and 5 g of castor oil polyoxyethylene ether, heat to 35° C., and stir for 2 h to obtain ternary copolymer defoamer B.

[0065] Table 1 Density method to test the performance of defoaming agent in styrene-butadiene latex

[0066]

[0067] Table 2 Compatibility of defoamers in coatings tested by brushing

[0068]

[0069] The defoaming test was conducted on styrene-butadiene latex, the main foaming component in water-based paint. As can be seen from Table 1, when no defoamer was added, the density of styrene-butadiene latex after stirring was very low, indicating that the system had a lot of foam. The acetylene alcohol defoamer made the density of styrene-butadiene latex 0.79 (g / cm 3 The density of the comparative example and the four embodiments in styrene-butadiene latex is the largest, indicating that bubbles are the least and the defoaming effect is the best.

[0070] Table 2 shows the compatibility of defoamers in coatings tested by brushing. When the blank was brushed without defoamer, a large number of foam spots were observed but no shrinkage cavities were found. When the silicone defoamer was added alone, no foam spots were observed but a large number of shrinkage cavities were found, indicating poor compatibility. When the comparative defoamer was added alone, a small number of foam spots and shrinkage cavities were found, indicating poor compatibility. The four examples had neither foam spots nor shrinkage cavities, indicating excellent compatibility.

[0071] Figure 1This is a foam suppression test of the defoaming agent. Conventional silicone defoamers have a fast defoaming speed, but poor subsequent foam suppression. Conventional polyether defoamers have a good continuous foam suppression effect but a slow defoaming speed. The comparative example has relatively good defoaming suppression. The four embodiments have great improvements in defoaming speed and foam suppression effect.

[0072] Therefore, the test results further confirm that the ternary copolymer defoamer has substantial improvement and obvious progress in defoaming, foam suppression and compatibility.

[0073] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features therein according to the disclosed technical content without creative labor, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. A method for preparing a ternary copolymer defoamer, characterized in that: include: Step 1), placing hydrogen silicone oil, acetylene alcohol and allyl polyether in a reaction kettle, heating to 85-95°C for the first time, evacuating to a negative pressure of ≤-0.09 MPa, evacuating for 25-35 minutes, and then stopping; placing nitrogen, adding a catalyst, heating to 120-135°C for the second time, keeping the temperature for 3-6 hours, and cooling to obtain a terpolymer; Step 2), mixing the terpolymer, polyether, solvent and emulsifier, heating and stirring to obtain a ternary copolymer defoamer; The alkynol has a carbon chain number of 6-12 and a hydroxyl number of 4-8; The hydrogen-containing silicone oil is end-containing hydrogen-containing silicone oil, side-containing hydrogen-containing silicone oil or end-side-containing hydrogen-containing silicone oil, the hydrogen content is 0.1-0.5%, and the molar ratio of hydrogen-containing silicone oil, acetylenic alcohol and allyl polyether is 1: (0.25-1.5): (0.5-2.5); The allyl polyether has a molecular weight of 450-2000, EO:PO=1:0.2-5, is methyl-terminated, and is randomly mixed with ethyl epoxide and propyl epoxide.

2. The method for preparing the ternary copolymer defoamer according to claim 1, wherein In step 2), the mixture is heated to 35-55° C. and stirred for 1-2 hours to obtain a ternary copolymer defoaming agent.

3. The method for preparing the ternary copolymer defoamer according to claim 1, wherein The catalyst is chloroplatinic acid, and the usage amount is 10-25ppm.

4. The method for preparing the ternary copolymer defoamer according to claim 1, wherein The polyether is one or a mixture of monofunctional, difunctional and trifunctional polyoxyethylene polyoxypropylene ethers.

5. The method for preparing the ternary copolymer defoamer according to claim 1, wherein The solvent is one or a mixture of castor oil, oleic acid, oleic acid glyceryl ester, stearic acid glyceryl ester and pentaerythritol stearate.

6. The method for preparing the ternary copolymer defoamer according to claim 1, wherein The emulsifier is one or a mixture of oleic acid polyoxyethylene ether, fatty alcohol polyoxyethylene ether, castor oil polyoxyethylene ether, and PEG200-800.

7. The method for preparing the ternary copolymer defoamer according to any one of claims 1 to 6, wherein: The mass fractions of the mixture used in step 2) are: 50-70% of terpolymer, 15-25% of polyether, 10-20% of solvent, and 5-10% of emulsifier.

8. A ternary copolymer defoamer prepared by the preparation method according to any one of claims 1 to 7.

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