Non-toxic polyether defoaming agent and preparation method thereof

Abstract

The invention discloses a non-toxic polyether defoaming agent and a preparation method thereof, and belongs to the technical field of polyether defoaming agent preparation. Mainly comprises the following raw materials in parts by mass: 70-80 parts of a polyether modified organosilicon surfactant, 15-25 parts of simethicone, 4-6 parts of hydrophobic fumed silica, 3-10 parts of an emulsifier, 2-6 parts of a thickener, 1-2 parts of an auxiliary agent and 60-80 parts of deionized water. The surface tension of an aqueous solution of an alkyl-modified organosilicon surfactant is lower, then hydrophobic-treated hydrated silicon dioxide, simethicone and a self-made organosilicon-modified polyether surfactant are compounded to prepare silicon paste, and then the silicon paste is mixed with an emulsifier, deionized water and a thickener to prepare the defoaming agent. Results of thermal stability, centrifugal stability, water dispersibility and practical application evaluation experiments of the defoaming agent show that the defoaming agent has good defoaming and foam inhibition performance, and hydrophobic groups in the defoaming agent can be increased due to the introduction of alkyl in the hydrogen-containing silicone oil.

Description

Technical Field

[0001] The invention belongs to the technical field of polyether defoamer preparation, and in particular relates to a non-toxic polyether defoamer and a preparation method thereof. Background Art

[0002] In most industrial production and applications, a large amount of foam will be generated, and its existence will seriously affect the quality of the product. Bubbles and foam are generated due to surface effects and can be regarded as a coarse dispersion of gas in liquid. The density of the gas and liquid phases is quite different. When the density of the bubbles is less than that of the liquid, the bubbles in the liquid phase will migrate to the surface. If there is a relatively stable liquid film on the liquid surface, the bubbles cannot escape to the outside, and foam will form on the surface of the liquid layer. Therefore, foam can be regarded as an aggregate of bubbles separated by a liquid film, which is thermodynamically unstable. Usually, bubbles formed in low-viscosity pure liquids will burst immediately when they escape from the liquid, and stable and lasting foam cannot be obtained. However, in industrial production, In the past, various additives were added to increase the viscosity of the liquid or reduce the surface tension. For example, the addition of surfactant molecules will cause them to adsorb at the gas-liquid interface, which not only reduces the surface tension between the two phases, but also forms a stable molecular film at the interface to stabilize the bubbles, thus obtaining foam with better stability. In theory, the purpose of defoaming can be achieved by destroying or removing the stable liquid film on the liquid surface. Therefore, as long as a substance that can reduce the strength of the foam liquid film is added to the liquid phase to make the foam liquid film thinner and weaker, the foam can be eliminated. The most commonly used method at present is to add a defoaming agent, which is added to the foaming system in the form of low concentration and low addition amount to control the generation of foam. This defoaming method is both simple and economical.

[0003] The prior art discloses some invention patents in the technical field of polyether defoamer preparation, among which the invention patent with publication number CN113384921B discloses a polyether defoamer and a preparation method thereof, comprising at least one of polyethylene glycol, modified polyethylene glycol or polyethylene glycol 6000 distearate, at least one of glycerol, polyglycerol or polyoxyethylene modified polyoxypropylene amine ether, propylene oxide and an auxiliary agent. The technical scheme prepares a polyether defoamer by mixing polyethylene glycol, modified polyethylene glycol or polyethylene glycol 6000 distearate, glycerol, polyglycerol or polyoxyethylene modified polyoxypropylene amine ether, propylene oxide and an auxiliary agent. Foaming agent, compared with the common polyether defoamers on the market, it has excellent defoaming ability and anti-foaming ability, strong emulsification, dispersion and penetration ability, can self-emulsify in water system, good stability, and has a lasting defoaming effect. The technical scheme still has some shortcomings in the application process. Polyether defoamers can be divided into polyol type, fatty acid ester type and amine ether type according to the different initiators used in the synthesis. Among them, the most widely used are polyol type and fatty acid ester type. Although the application of polyether defoamers is relatively wide, the defoaming ingredients of the defoaming agent are single, mainly using polyether substances, the defoaming effect is poor, and the content of polyether substances is too high, which is not conducive to the application in food.

[0004] Based on this, the present invention designs a non-toxic polyether defoamer and a preparation method thereof to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that polyether defoamers are widely used, but the defoaming components of the defoamers are single, mainly polyether substances are used, the defoaming effect is poor, and the content of polyether substances is too high, which is not conducive to the application in food. A non-toxic polyether defoamer and a preparation method thereof are proposed.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A non-toxic polyether defoamer mainly consists of the following raw materials in parts by mass: 70-80 parts of polyether modified silicone surfactant, 15-25 parts of dimethyl silicone oil, 4-6 parts of hydrophobic fumed silica, 3-10 parts of emulsifier, 2-6 parts of thickener, 1-2 parts of auxiliary agent and 60-80 parts of deionized water;

[0008] The synthesis of the alkyl hydrogen silicone oil comprises:

[0009] A certain amount of hydrogenated silicone oil, α-olefin, allyl alcohol polyoxyalkyl ether and catalyst were added to a four-necked flask, nitrogen was introduced for 12 minutes, and then heating and stirring were performed simultaneously;

[0010] When the temperature inside the four-necked flask is heated to 80°C, stop introducing nitrogen into the four-necked flask and continue heating the four-necked flask to the desired reaction temperature;

[0011] After the reaction is completed, the catalyst is removed by natural cooling to room temperature based on the filtration technology.

[0012] As a further description of the above technical solution:

[0013] The four-necked flask is equipped with an electromagnetic stirrer, a thermometer and a reflux condenser, and the reaction time is 7-9 hours.

[0014] As a further description of the above technical solution:

[0015] In the production of the alkyl hydrogen-containing silicone oil, the hydrogen content of the silicone oil is determined by back titration. The silicon-hydrogen bond reacts with bromine under acidic conditions to generate hydrogen bromide. Excess bromine reacts with potassium iodide, and the precipitated iodine is titrated with sodium thiosulfate. The double bond content of α-olefin and allyl alcohol polyoxyalkyl ether is determined by chloroform-iodine titration. The feed ratio is controlled by determining the double bond content and then the hydrogen content in the hydrogen-containing silicone oil.

[0016] As a further description of the above technical solution:

[0017] The preparation of the catalyst comprises:

[0018] Alumina was used as a carrier, which was immersed in distilled water for 26 h, then dried and kept constant in a vacuum environment at 110 °C until constant weight;

[0019] Weigh a certain amount of aluminum oxide and add it to a four-necked flask, then add a concentrated chloroplatinic acid-isopropanol solution, and reflux at 84°C for 2.6-3h under magnetic stirring of an electromagnetic stirrer, and filter;

[0020] The solid obtained after filtration was washed several times with isopropanol and then dried at a constant temperature of 84°C in a vacuum environment.

[0021] As a further description of the above technical solution:

[0022] The platinum loading in the catalyst is 1.9-2.0%, and the platinum loading in the catalyst is determined by measuring its absorbance at 265nm using an ultraviolet spectrophotometer.

[0023] As a further description of the above technical solution:

[0024] The polyether modified silicone surfactant

[0025] The preparation of the polyether-modified silicone surfactant comprises:

[0026] Weigh a certain amount of allyl polyether and hydrogen-containing silicone oil, add them into a three-necked flask equipped with an electromagnetic stirrer, and heat and stir to mix;

[0027] After the allyl polyether and the hydrogenated silicone oil are uniformly mixed, chloroplatinic acid-isopropanol catalyst is added to the three-necked flask in a dropwise manner;

[0028] After a period of reaction, a transparent viscous liquid is obtained, which is the polyether-modified silicone surfactant.

[0029] As a further description of the above technical solution:

[0030] During the dropwise addition of the chloroplatinic acid-isopropanol catalyst, nitrogen was introduced into the three-necked flask, and after the dropwise addition of the chloroplatinic acid-isopropanol catalyst was completed, the mixture was stirred for 8 minutes, and the temperature was raised to 74-76° C. under the protection of a nitrogen atmosphere. After the temperature was kept for 0.8-1 hour, the alkyl hydrogenated silicone oil prepared in the above step was added dropwise.

[0031] As a further description of the above technical solution:

[0032] After the alkyl hydrogen silicone oil is added dropwise to the three-necked flask, the reaction is carried out for 3-4 hours, and the degree of reaction is controlled by infrared monitoring to see whether the -Si-H peak disappears completely.

[0033] As a further description of the above technical solution:

[0034] The auxiliary agent includes a penetrant, a diffusant and a stabilizer. The penetrant is one of sodium benzoate, methanol or octanol, the diffusant is one of sodium methylenebisphthalate sulfonate or NPE-7, and the stabilizer is one of epoxy triglyceride, epoxy stearate butyl or octyl ester or a mixture of several thereof.

[0035] A method for preparing a non-toxic polyether defoamer, the synthesis of the polyether defoamer comprising the following steps:

[0036] A self-made polyether-modified silicone surfactant, dimethyl silicone oil and hydrophobic fumed silica were sequentially added into a four-necked flask equipped with an electromagnetic stirrer and a thermostat, and the four-necked flask was heated under nitrogen protection. After the temperature inside the four-necked flask was raised to 160° C. and stirred for 3 hours, it was naturally cooled to room temperature to prepare a silicone paste;

[0037] Then, add silicone paste and emulsifier into a three-necked flask equipped with an electromagnetic stirrer and a thermometer, heat the three-necked flask to 60°C and stir for 1 hour until the emulsifier is completely dissolved and evenly mixed with the silicone paste;

[0038] Then use shear emulsification equipment to emulsify for 14-16 mi at a shear speed of 4800-5000 r / min, and slowly add thickener while stirring to keep the system at a constant temperature;

[0039] Then, deionized water is slowly added into the three-necked flask, and stirring is continued for 1-1.2 hours before discharging the material to prepare a non-toxic polyether defoamer.

[0040] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0041] In the present invention, the surface tension of the aqueous solution of the alkyl-modified organic silicon surfactant is lower, and then the hydrophobically treated hydrated silicon dioxide, dimethyl silicone oil and a homemade organic silicon-modified polyether surfactant are compounded to prepare a silicone paste, which is then mixed with an emulsifier, deionized water and a thickener to prepare a defoamer. The thermal stability, centrifugal stability, water dispersibility and practical application evaluation experiments of the defoamer are carried out, and the results show that the defoamer has good defoaming and anti-foaming properties, and the introduction of the alkyl group in the hydrogen-containing silicone oil can increase the hydrophobic group in the defoamer, reduce the surface tension of the defoamer in the action system, make the foam unstable, and be beneficial to the final defoaming effect. DETAILED DESCRIPTION

[0042] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0043] Embodiment 1

[0044] A non-toxic polyether defoamer, mainly composed of the following raw materials in parts by mass: 70 parts of polyether modified silicone surfactant, 15 parts of dimethyl silicone oil, 4 parts of hydrophobic fumed silica, 3 parts of emulsifier, 2 parts of thickener, 1 part of auxiliary agent and 60 parts of deionized water;

[0045] The synthesis of the polyether defoamer comprises the following steps:

[0046] A self-made polyether-modified silicone surfactant, dimethyl silicone oil and hydrophobic fumed silica were sequentially added into a four-necked flask equipped with an electromagnetic stirrer and a thermostat, and the four-necked flask was heated under nitrogen protection. After the temperature inside the four-necked flask was raised to 160° C. and stirred for 3 hours, it was naturally cooled to room temperature to prepare a silicone paste;

[0047] Then, add silicone paste and emulsifier into a three-necked flask equipped with an electromagnetic stirrer and a thermometer, heat the three-necked flask to 60°C and stir for 1 hour until the emulsifier is completely dissolved and evenly mixed with the silicone paste;

[0048] Then use shear emulsification equipment to emulsify for 14-16 mi at a shear speed of 4800-5000 r / min, and slowly add thickener while stirring to keep the system at a constant temperature;

[0049] Then, deionized water is slowly added to the three-necked flask, and the mixture is discharged after stirring for 1-1.2 hours to prepare a non-toxic polyether defoamer;

[0050] Specifically, the synthesis of the alkyl hydrogen silicone oil includes:

[0051] A certain amount of hydrogenated silicone oil, α-olefin, allyl alcohol polyoxyalkyl ether and catalyst were added to a four-necked flask, nitrogen was introduced for 12 minutes, and then heating and stirring were performed simultaneously;

[0052] When the temperature inside the four-necked flask is heated to 80°C, stop introducing nitrogen into the four-necked flask and continue heating the four-necked flask to the desired reaction temperature;

[0053] After the reaction is completed, the catalyst is removed by natural cooling to room temperature based on the filtration technology;

[0054] Specifically, the four-necked flask is equipped with an electromagnetic stirrer, a thermometer and a reflux condenser, and the reaction time is 7-9 hours;

[0055] Specifically, in the production of the alkyl hydrogen-containing silicone oil, the hydrogen content of the silicone oil is determined by back titration, the silicon-hydrogen bond reacts with bromine under acidic conditions to generate hydrogen bromide, the excess bromine reacts with potassium iodide, the precipitated iodine is titrated with sodium thiosulfate, and the double bond content of α-olefin and allyl alcohol polyoxyalkyl ether is determined by chloroform-iodine titration, the double bond content is determined, and then the hydrogen content in the hydrogen-containing silicone oil is determined, so as to control the feed ratio;

[0056] Specifically, the preparation of the catalyst includes:

[0057] Alumina was used as a carrier, which was immersed in distilled water for 26 h, then dried and kept constant in a vacuum environment at 110 °C until constant weight;

[0058] Weigh a certain amount of aluminum oxide and add it to a four-necked flask, then add a concentrated chloroplatinic acid-isopropanol solution, and reflux at 84°C for 2.6-3h under magnetic stirring of an electromagnetic stirrer, and filter;

[0059] The solid obtained after filtration was washed several times with isopropanol and then dried at 84°C in a vacuum environment;

[0060] Specifically, the platinum loading in the catalyst is 1.9-2.0%, and the platinum loading in the catalyst is determined by measuring its absorbance at 265nm using an ultraviolet spectrophotometer;

[0061] Specifically, the polyether-modified silicone surfactant

[0062] The preparation of the polyether-modified silicone surfactant comprises:

[0063] Weigh a certain amount of allyl polyether and hydrogen-containing silicone oil, add them into a three-necked flask equipped with an electromagnetic stirrer, and heat and stir to mix;

[0064] After the allyl polyether and the hydrogenated silicone oil are uniformly mixed, chloroplatinic acid-isopropanol catalyst is added to the three-necked flask in a dropwise manner;

[0065] After a period of reaction, a transparent viscous liquid is obtained, which is the polyether-modified silicone surfactant;

[0066] Specifically, during the dropwise addition of the chloroplatinic acid-isopropanol catalyst, nitrogen was introduced into the three-necked flask, and after the dropwise addition of the chloroplatinic acid-isopropanol catalyst was completed, the mixture was stirred for 8 minutes, and the temperature was raised to 74-76° C. under the protection of a nitrogen atmosphere, and the alkyl hydrogenated silicone oil prepared in the above step was added dropwise after being kept warm for 0.8-1 hour;

[0067] Specifically, after the alkyl hydrogen silicone oil is added dropwise to the three-necked flask, the reaction is continued for 3-4 hours, and the degree of reaction is controlled by infrared monitoring to see whether the -Si-H peak disappears completely;

[0068] Specifically, the auxiliary agent includes a penetrant, a diffusant and a stabilizer. The penetrant is one of sodium benzoate, methanol or octanol, the diffusant is one of sodium methylenebisphthalate sulfonate or NPE-7, and the stabilizer is one of epoxy triglyceride, epoxy stearate butyl or octyl ester or a mixture of several thereof.

[0069] Embodiment 2

[0070] A non-toxic polyether defoamer, mainly composed of the following raw materials in parts by mass: 80 parts of polyether modified silicone surfactant, 25 parts of dimethyl silicone oil, 6 parts of hydrophobic fumed silica, 10 parts of emulsifier, 6 parts of thickener, 2 parts of auxiliary agent and 80 parts of deionized water;

[0071] The synthesis of the polyether defoamer comprises the following steps:

[0072] A self-made polyether-modified silicone surfactant, dimethyl silicone oil and hydrophobic fumed silica were sequentially added into a four-necked flask equipped with an electromagnetic stirrer and a thermostat, and the four-necked flask was heated under nitrogen protection. After the temperature inside the four-necked flask was raised to 160° C. and stirred for 3 hours, it was naturally cooled to room temperature to prepare a silicone paste;

[0073] Then, add silicone paste and emulsifier into a three-necked flask equipped with an electromagnetic stirrer and a thermometer, heat the three-necked flask to 60°C and stir for 1 hour until the emulsifier is completely dissolved and evenly mixed with the silicone paste;

[0074] Then use shear emulsification equipment to emulsify for 14-16 mi at a shear speed of 4800-5000 r / min, and slowly add thickener while stirring to keep the system at a constant temperature;

[0075] Then, deionized water is slowly added to the three-necked flask, and the mixture is discharged after stirring for 1-1.2 hours to prepare a non-toxic polyether defoamer;

[0076] Specifically, the synthesis of the alkyl hydrogen silicone oil includes:

[0077] A certain amount of hydrogenated silicone oil, α-olefin, allyl alcohol polyoxyalkyl ether and catalyst were added to a four-necked flask, nitrogen was introduced for 12 minutes, and then heating and stirring were performed simultaneously;

[0078] When the temperature inside the four-necked flask is heated to 80°C, stop introducing nitrogen into the four-necked flask and continue heating the four-necked flask to the desired reaction temperature;

[0079] After the reaction is completed, the catalyst is removed by natural cooling to room temperature based on the filtration technology;

[0080] Specifically, the four-necked flask is equipped with an electromagnetic stirrer, a thermometer and a reflux condenser, and the reaction time is 7-9 hours;

[0081] Specifically, in the production of the alkyl hydrogen-containing silicone oil, the hydrogen content of the silicone oil is determined by back titration, the silicon-hydrogen bond reacts with bromine under acidic conditions to generate hydrogen bromide, the excess bromine reacts with potassium iodide, the precipitated iodine is titrated with sodium thiosulfate, and the double bond content of α-olefin and allyl alcohol polyoxyalkyl ether is determined by chloroform-iodine titration, the double bond content is determined, and then the hydrogen content in the hydrogen-containing silicone oil is determined, so as to control the feed ratio;

[0082] Specifically, the preparation of the catalyst includes:

[0083] Alumina was used as a carrier, which was immersed in distilled water for 26 h, then dried and kept constant in a vacuum environment at 110 °C until constant weight;

[0084] Weigh a certain amount of aluminum oxide and add it to a four-necked flask, then add a concentrated chloroplatinic acid-isopropanol solution, and reflux at 84°C for 2.6-3h under magnetic stirring of an electromagnetic stirrer, and filter;

[0085] The solid obtained after filtration was washed several times with isopropanol and then dried at 84°C in a vacuum environment;

[0086] Specifically, the platinum loading in the catalyst is 1.9-2.0%, and the platinum loading in the catalyst is determined by measuring its absorbance at 265nm using an ultraviolet spectrophotometer;

[0087] Specifically, the polyether-modified silicone surfactant

[0088] The preparation of the polyether-modified silicone surfactant comprises:

[0089] Weigh a certain amount of allyl polyether and hydrogen-containing silicone oil, add them into a three-necked flask equipped with an electromagnetic stirrer, and heat and stir to mix;

[0090] After the allyl polyether and the hydrogenated silicone oil are uniformly mixed, chloroplatinic acid-isopropanol catalyst is added to the three-necked flask in a dropwise manner;

[0091] After a period of reaction, a transparent viscous liquid is obtained, which is the polyether-modified silicone surfactant;

[0092] Specifically, during the dropwise addition of the chloroplatinic acid-isopropanol catalyst, nitrogen was introduced into the three-necked flask, and after the dropwise addition of the chloroplatinic acid-isopropanol catalyst was completed, the mixture was stirred for 8 minutes, and the temperature was raised to 74-76° C. under the protection of a nitrogen atmosphere, and the alkyl hydrogenated silicone oil prepared in the above step was added dropwise after being kept warm for 0.8-1 hour;

[0093] Specifically, after the alkyl hydrogen silicone oil is added dropwise to the three-necked flask, the reaction is continued for 3-4 hours, and the degree of reaction is controlled by infrared monitoring to see whether the -Si-H peak disappears completely;

[0094] Specifically, the auxiliary agent includes a penetrant, a diffusant and a stabilizer. The penetrant is one of sodium benzoate, methanol or octanol, the diffusant is one of sodium methylenebisphthalate sulfonate or NPE-7, and the stabilizer is one of epoxy triglyceride, epoxy stearate butyl or octyl ester or a mixture of several thereof.

[0095] Embodiment 3

[0096] A non-toxic polyether defoamer, mainly composed of the following raw materials in parts by mass: 75 parts of polyether modified silicone surfactant, 20 parts of dimethyl silicone oil, 5 parts of hydrophobic fumed silica, 6.5 parts of emulsifier, 4 parts of thickener, 1.5 parts of auxiliary agent and 70 parts of deionized water;

[0097] The synthesis of the polyether defoamer comprises the following steps:

[0098] A self-made polyether-modified silicone surfactant, dimethyl silicone oil and hydrophobic fumed silica were sequentially added into a four-necked flask equipped with an electromagnetic stirrer and a thermostat, and the four-necked flask was heated under nitrogen protection. After the temperature inside the four-necked flask was raised to 160° C. and stirred for 3 hours, it was naturally cooled to room temperature to prepare a silicone paste;

[0099] Then, add silicone paste and emulsifier into a three-necked flask equipped with an electromagnetic stirrer and a thermometer, heat the three-necked flask to 60°C and stir for 1 hour until the emulsifier is completely dissolved and evenly mixed with the silicone paste;

[0100] Then use shear emulsification equipment to emulsify for 14-16 mi at a shear speed of 4800-5000 r / min, and slowly add thickener while stirring to keep the system at a constant temperature;

[0101] Then, deionized water is slowly added to the three-necked flask, and the mixture is discharged after stirring for 1-1.2 hours to prepare a non-toxic polyether defoamer;

[0102] Specifically, the synthesis of the alkyl hydrogen silicone oil includes:

[0103] A certain amount of hydrogenated silicone oil, α-olefin, allyl alcohol polyoxyalkyl ether and catalyst were added to a four-necked flask, nitrogen was introduced for 12 minutes, and then heating and stirring were performed simultaneously;

[0104] When the temperature inside the four-necked flask is heated to 80°C, stop introducing nitrogen into the four-necked flask and continue heating the four-necked flask to the desired reaction temperature;

[0105] After the reaction is completed, the catalyst is removed by natural cooling to room temperature based on the filtration technology;

[0106] Specifically, the four-necked flask is equipped with an electromagnetic stirrer, a thermometer and a reflux condenser, and the reaction time is 7-9 hours;

[0107] Specifically, in the production of the alkyl hydrogen-containing silicone oil, the hydrogen content of the silicone oil is determined by back titration, the silicon-hydrogen bond reacts with bromine under acidic conditions to generate hydrogen bromide, the excess bromine reacts with potassium iodide, the precipitated iodine is titrated with sodium thiosulfate, and the double bond content of α-olefin and allyl alcohol polyoxyalkyl ether is determined by chloroform-iodine titration, the double bond content is determined, and then the hydrogen content in the hydrogen-containing silicone oil is determined, so as to control the feed ratio;

[0108] Specifically, the preparation of the catalyst includes:

[0109] Alumina was used as a carrier, which was immersed in distilled water for 26 h, then dried and kept constant in a vacuum environment at 110 °C until constant weight;

[0110] Weigh a certain amount of aluminum oxide and add it to a four-necked flask, then add a concentrated chloroplatinic acid-isopropanol solution, and reflux at 84°C for 2.6-3h under magnetic stirring of an electromagnetic stirrer, and filter;

[0111] The solid obtained after filtration was washed several times with isopropanol and then dried at 84°C in a vacuum environment;

[0112] Specifically, the platinum loading in the catalyst is 1.9-2.0%, and the platinum loading in the catalyst is determined by measuring its absorbance at 265nm using an ultraviolet spectrophotometer;

[0113] Specifically, the polyether-modified silicone surfactant

[0114] The preparation of the polyether-modified silicone surfactant comprises:

[0115] Weigh a certain amount of allyl polyether and hydrogen-containing silicone oil, add them into a three-necked flask equipped with an electromagnetic stirrer, and heat and stir to mix;

[0116] After the allyl polyether and the hydrogenated silicone oil are uniformly mixed, chloroplatinic acid-isopropanol catalyst is added to the three-necked flask in a dropwise manner;

[0117] After a period of reaction, a transparent viscous liquid is obtained, which is the polyether-modified silicone surfactant;

[0118] Specifically, during the dropwise addition of the chloroplatinic acid-isopropanol catalyst, nitrogen was introduced into the three-necked flask, and after the dropwise addition of the chloroplatinic acid-isopropanol catalyst was completed, the mixture was stirred for 8 minutes, and the temperature was raised to 74-76° C. under the protection of a nitrogen atmosphere, and the alkyl hydrogenated silicone oil prepared in the above step was added dropwise after being kept warm for 0.8-1 hour;

[0119] Specifically, after the alkyl hydrogen silicone oil is added dropwise to the three-necked flask, the reaction is continued for 3-4 hours, and the degree of reaction is controlled by infrared monitoring to see whether the -Si-H peak disappears completely;

[0120] Specifically, the auxiliary agent includes a penetrant, a diffusant and a stabilizer. The penetrant is one of sodium benzoate, methanol or octanol, the diffusant is one of sodium methylenebisphthalate sulfonate or NPE-7, and the stabilizer is one of epoxy triglyceride, epoxy stearate butyl or octyl ester or a mixture of several thereof.

[0121] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A non-toxic polyether defoamer, characterized in that: The invention is mainly composed of the following raw materials in parts by mass: 70-80 parts of polyether modified silicone surfactant, 15-25 parts of dimethyl silicone oil, 4-6 parts of hydrophobic fumed silica, 3-10 parts of emulsifier, 2-6 parts of thickener, 1-2 parts of auxiliary agent and 60-80 parts of deionized water; The synthesis of the alkyl hydrogen silicone oil comprises: A certain amount of hydrogenated silicone oil, α-olefin, allyl alcohol polyoxyalkyl ether and catalyst were added to a four-necked flask, nitrogen was introduced for 12 minutes, and then heating and stirring were performed simultaneously; When the temperature inside the four-necked flask is heated to 80°C, stop introducing nitrogen into the four-necked flask and continue heating the four-necked flask to the desired reaction temperature; After the reaction is completed, the catalyst is removed by natural cooling to room temperature based on the filtration technology.

2. A non-toxic polyether defoamer according to claim 1, characterized in that: The four-necked flask is equipped with an electromagnetic stirrer, a thermometer and a reflux condenser, and the reaction time is 7-9 hours.

3. A non-toxic polyether defoamer according to claim 2, characterized in that: In the production of the alkyl hydrogen-containing silicone oil, the hydrogen content of the silicone oil is determined by back titration. The silicon-hydrogen bond reacts with bromine under acidic conditions to generate hydrogen bromide. Excess bromine reacts with potassium iodide, and the precipitated iodine is titrated with sodium thiosulfate. The double bond content of α-olefin and allyl alcohol polyoxyalkyl ether is determined by chloroform-iodine titration. The feed ratio is controlled by determining the double bond content and then the hydrogen content in the hydrogen-containing silicone oil.

4. A non-toxic polyether defoamer according to claim 1, characterized in that: The preparation of the catalyst comprises: Alumina was used as a carrier, which was immersed in distilled water for 26 h, then dried and kept constant in a vacuum environment at 110 °C until constant weight; Weigh a certain amount of aluminum oxide and add it to a four-necked flask, then add a concentrated chloroplatinic acid-isopropanol solution, and reflux at 84°C for 2.6-3h under magnetic stirring of an electromagnetic stirrer, and filter; The solid obtained after filtration was washed several times with isopropanol and then dried at a constant temperature of 84°C in a vacuum environment.

5. A non-toxic polyether defoamer according to claim 4, characterized in that: The platinum loading in the catalyst is 1.9-2.0%, and the platinum loading in the catalyst is determined by measuring its absorbance at 265nm using an ultraviolet spectrophotometer.

6. A non-toxic polyether defoamer according to claim 1, characterized in that: The polyether modified silicone surfactant The preparation of the polyether-modified silicone surfactant comprises: Weigh a certain amount of allyl polyether and hydrogen-containing silicone oil, add them into a three-necked flask equipped with an electromagnetic stirrer, and heat and stir to mix; After the allyl polyether and the hydrogenated silicone oil are uniformly mixed, chloroplatinic acid-isopropanol catalyst is added to the three-necked flask in a dropwise manner; After a period of reaction, a transparent viscous liquid is obtained, which is the polyether-modified silicone surfactant.

7. A non-toxic polyether defoamer according to claim 6, characterized in that: During the dropwise addition of the chloroplatinic acid-isopropanol catalyst, nitrogen was introduced into the three-necked flask, and after the dropwise addition of the chloroplatinic acid-isopropanol catalyst was completed, the mixture was stirred for 8 minutes, and the temperature was raised to 74-76° C. under the protection of a nitrogen atmosphere. After the temperature was kept for 0.8-1 hour, the alkyl hydrogenated silicone oil prepared in the above step was added dropwise.

8. A non-toxic polyether defoamer according to claim 7, characterized in that: After the alkyl hydrogen silicone oil is added dropwise to the three-necked flask, the reaction is carried out for 3-4 hours, and the degree of reaction is controlled by infrared monitoring to see whether the -Si-H peak disappears completely.

9. A non-toxic polyether defoamer according to claim 1, characterized in that: The auxiliary agent includes a penetrant, a diffusant and a stabilizer. The penetrant is one of sodium benzoate, methanol or octanol, the diffusant is one of sodium methylenebisphthalate sulfonate or NPE-7, and the stabilizer is one of epoxy triglyceride, epoxy stearate butyl or octyl ester or a mixture of several thereof.

10. A method for preparing a non-toxic polyether defoamer, according to a non-toxic polyether defoamer according to claim 1-9, characterized in that: The synthesis of the polyether defoamer comprises the following steps: A self-made polyether-modified silicone surfactant, dimethyl silicone oil and hydrophobic fumed silica were sequentially added into a four-necked flask equipped with an electromagnetic stirrer and a thermostat, and the four-necked flask was heated under nitrogen protection. After the temperature inside the four-necked flask was raised to 160° C. and stirred for 3 hours, it was naturally cooled to room temperature to prepare a silicone paste; Then, add silicone paste and emulsifier into a three-necked flask equipped with an electromagnetic stirrer and a thermometer, heat the three-necked flask to 60°C and stir for 1 hour until the emulsifier is completely dissolved and evenly mixed with the silicone paste; Then use shear emulsification equipment to emulsify for 14-16 mi at a shear speed of 4800-5000 r / min, and slowly add thickener while stirring to keep the system at a constant temperature; Then, deionized water is slowly added into the three-necked flask, and stirring is continued for 1-1.2 hours before discharging the material to prepare a non-toxic polyether defoamer.