Preparation method of polyether composition

Abstract

The invention relates to a preparation method of a polyether composition. The raw materials comprise branched synthetic fatty alcohol polyether, secondary alcohol polyether, oleic acid polyether, silicon dioxide and a synergist. The components are mixed according to a certain process to form the stable polyether composition, foam can be controlled at an acceptable degree, and the stable polyether composition has a good synergistic effect on wetting and leveling. The polyether composition not only can be used for foam control and surface control of water-based paint, but also can be used in other systems, such as water-based ink, a water-based adhesive, industrial slag water, landfill leachate and the like, which cannot use an organic silicon defoaming agent.

Description

Technical Field

[0001] This invention relates to a method for preparing a polyether composition, belonging to the field of fine chemical technology. Background Technology

[0002] The coatings industry is an important sector of the national economy. In recent years, with increasing awareness of environmental protection, many cities have begun to switch from oil-based to water-based coatings, leading to a booming development of water-based coatings.

[0003] Water-based coatings generally consist of water-based binders, pigments, fillers, dispersants, thickeners, wetting agents, leveling agents, and defoamers. Wetting agents, leveling agents, and dispersants are all surfactants, which easily foam during the coating grinding and dispersion process, leading to decreased production efficiency or even halted production. The resulting dry film may also exhibit defects such as pinholes and fisheyes, failing to achieve satisfactory results. Therefore, foam control is a crucial and indispensable step, making defoamers an essential additive in water-based coatings.

[0004] Defoamers used in water-based coatings fall into two main categories: modified silicone defoamers and mineral oil defoamers. Mineral oil defoamers, as an earlier developed type of coating defoamer, are widely used in some coating systems. However, their poor defoaming ability, high dosage requirements, and impact on gloss have limited their application and promotion in mid-to-high-end coating systems. Modified silicone defoamers have also been extensively documented in coating applications. For example, CN102527096A describes a method for preparing a silicone defoamer by grafting dendritic polyether groups onto the silicone backbone, addressing the issues of defoaming speed and temperature sensitivity. CN102993815A describes a composition of end-capped polyether-modified silicone as a degassing agent in coating application. CN104667585A describes a method for preparing a defoamer by compounding polyether-modified polysiloxane with a surfactant, demonstrating good defoaming performance. These technologies all use polyether-modified polysiloxanes, supplemented with silicone paste or a large amount of precipitated silica to enhance defoaming properties. These products exist in two main forms: one is a 100% water- and diluent-free product; the other is an emulsion product formed by dispersing active ingredients in water through emulsification. Furthermore, the primary control point for these products is foam control, with minimal impact on the wetting and leveling properties of coatings and inks.

[0005] Through extensive experimental research, the inventors of this patent discovered that the product obtained by blending synthetic alcohol polyethers, secondary alcohol polyethers, and alkynyl alcohol polyethers can control foam to an acceptable level and has a good synergistic effect on wetting and leveling. This polyether composition can be used not only for foam control and surface control in water-based coatings, but also in other systems where silicone defoamers cannot be used, such as water-based inks, water-based adhesives, industrial slag water, and landfill leachate systems. Summary of the Invention

[0006] The purpose of this invention is to disclose a polyether composition that combines foam control and surface control features in water-based coating systems.

[0007] The raw materials for preparing the polyether composition include: (A) branched synthetic fatty alcohol polyether, (B) secondary alcohol polyether, (C) oleic acid polyether, (D) silica and (E) synergist.

[0008] A. Branched synthesis of fatty alcohol polyethers

[0009] Branched synthetic fatty alcohol polyethers are synthesized by combining synthetic fatty alcohol polyethers with trimethylolpropane under alkaline conditions.

[0010] The synthetic fatty alcohols mentioned refer to alcohols obtained from ethylene using the Ziegler process or the OXO process.

[0011] The synthetic fatty alcohol polyether is prepared by an addition reaction of a synthetic fatty alcohol with a monofunctional group having 6 to 30 carbon atoms with ethylene oxide (EO) and propylene oxide (PO). Its general structural formula is as follows:

[0012] RO(EO) a (PO) b H

[0013] (I)

[0014] In formula (Ⅰ), R is the functional group in the polyether initiator; the subscripts a and b are the degree of polymerization of EO and PO, respectively, where a is 0 or 1 to 10 and b is 10 to 40.

[0015] The mass ratio of the main raw material for preparing the branched synthetic fatty alcohol polyether, synthetic fatty alcohol polyether, and trimethylolpropane is 5:1 to 35:1.

[0016] The catalyst for preparing the branched synthetic fatty alcohol polyether is selected from sodium hydroxide, potassium hydroxide, and cesium hydroxide, and the amount used is 0.5-2% of the total mass of the synthetic fatty alcohol polyether and trimethylolpropane. The catalyst is used in the form of an aqueous solution with a mass percentage concentration of 30-50%.

[0017] The solvent used to prepare the branched synthetic fatty alcohol polyether is one or a mixture of toluene and xylene, and the amount used is 50-70% of the total mass of the synthetic fatty alcohol polyether and trimethylolpropane.

[0018] The method for preparing the aforementioned branched synthetic fatty alcohol polyether is as follows:

[0019] The required amounts of synthetic fatty alcohol polyether, catalyst aqueous solution, and solvent are added to a reactor equipped with a stirrer, thermometer, and condenser. The temperature is then raised to reflux temperature and maintained for 1–3 hours. Trimethylolpropane is then slowly added dropwise to the system over 20–120 minutes. After the addition is complete, the reaction continues at reflux temperature for 6–24 hours. Finally, the solids are removed by filtration, and the solvent toluene is removed by distillation and vacuum distillation to obtain the branched synthetic fatty alcohol polyether.

[0020] The amount of the branched synthetic fatty alcohol polyether used is 60-80% of the total mass of the polyether composition.

[0021] B. Secondary alcohol polyether

[0022] The secondary alcohol polyether is prepared by an addition reaction of a monohydric alcohol with an active hydroxyl group at the secondary position having 4 to 22 carbon atoms with ethylene oxide (EO) and propylene oxide (PO) as an initiator.

[0023] The general structural formula of the secondary alcohol polyether is as follows:

[0024] R 1 O(EO) c (PO) d H

[0025] (II)

[0026] In formula (II), the subscripts c and d represent the degree of polymerization of EO and PO, where c is 1 to 10 and d is 5 to 25;

[0027] The amount of the secondary alcohol polyether used is 5-15% of the total mass of the polyether composition;

[0028] The mass ratio of the branched synthetic fatty alcohol polyether to the secondary alcohol polyether is 15:1 to 4:1.

[0029] C. Oleic acid polyether

[0030] The oleic acid polyether is used to emulsify and disperse polyether compositions, and its general structural formula is as follows:

[0031] C 17 H 33 COO(EO) e OCH 33 C 17

[0032] (III)

[0033] In formula (Ⅲ), the subscript e represents the degree of polymerization of ethylene oxide (EO), which is 6 to 15.

[0034] The amount of oleic acid polyether used is 5-20% of the total mass of the polyether composition.

[0035] D. Silicon dioxide

[0036] Silica is classified into two types according to its manufacturing method: precipitated silica and fumed silica. It is also classified into two types according to its surface properties: hydrophilic silica and hydrophobic silica. Hydrophobic silica is obtained by heating and stirring hydrophilic silica and a hydrophobic agent in a reaction vessel. Materials that make silica surfaces hydrophobic include low-viscosity trimethylsiloxy-terminated polydimethylsiloxane, low-viscosity hydroxyl-terminated polydimethylsiloxane, hexamethyldisilazane, hexamethyldisilazane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, tetrachlorosilane, stearic acid, stearyl alcohol, octamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, and hexamethylcyclotrisiloxane.

[0037] The silica described in this invention has a specific surface area of ​​60–400 m². 2 / g precipitated hydrophobic silica, the hydrophobic treatment agent is hexamethyldisilazane, and the hydrophobicity value by methanol method is 40-60%.

[0038] The amount of silica used is 3 to 10% of the total mass of the polyether composition.

[0039] E. Synergists

[0040] The synergist is mainly used to further improve the defoaming effect of the polyether composition. It is a product formed by polyethylsiloxane, hydrophobic silica and lipophilic polyether-modified polysiloxane under the action of an alkaline catalyst. It is selected from Dow Corning's 1247, 1266, DC544, 7600, 7800 and Wacker's SD 850, SD 860, Pulpsil235C.

[0041] The amount of the synergist used is 0.1-3% of the total mass of the polyether composition.

[0042] The method for preparing the polyether composition of the present invention is as follows:

[0043] At room temperature, branched synthetic fatty alcohol polyether and secondary alcohol polyether are added to a container, and stirring is started at a speed of 1000-3000 rpm. Then, silica is added to the reactor within 5-30 minutes, and dispersion is continued for 1-3 hours. After that, the mixture is processed through a homogenizer at a pressure of 3-10 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion". Finally, oleic acid polyether and a synergist are added to the "polyether-silica dispersion" at a speed of 500-2000 rpm, and the mixture is stirred for 10-30 minutes to obtain the product of this invention. Detailed Implementation

[0044] Example 1:

[0045] Examples of synthetic fatty alcohols:

[0046] Synthetic fatty alcohol polyether SAP Initiator a b SAP-1 Alfol20+ 0 25 SAP-2 Nafol20+A 2 38 SAP-3 Nafol 22+ 10 10 SAP-4 Nafol2022 6 16 SAP-5 Nafol20+A 5 28

[0047] Example 2:

[0048] Preparation of branched synthetic fatty alcohol polyether A1:

[0049] 100g of synthetic fatty alcohol polyether SAP-1, 1.2g of 50% sodium hydroxide aqueous solution, and 60g of toluene were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. The temperature was then raised to reflux temperature and maintained for 1 hour. 20g of trimethylolpropane was then slowly added dropwise to the system over 100 minutes. After the addition was complete, the reaction was continued at reflux temperature for another 18 hours. Finally, the solids were removed by filtration, and the solvent toluene was removed by distillation and vacuum distillation to obtain branched synthetic fatty alcohol polyether A1.

[0050] Example 3:

[0051] Preparation of branched synthetic fatty alcohol polyether A2:

[0052] 105g of synthetic fatty alcohol polyether SAP-5, 3.6g of 30% potassium hydroxide aqueous solution, and 75g of xylene were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. The temperature was then raised to reflux temperature and maintained for 3 hours. 3g of trimethylolpropane was then slowly added dropwise to the system over 25 minutes. After the addition was complete, the reaction was continued at reflux temperature for another 6.5 hours. Finally, the solids were removed by filtration, and the solvent toluene was removed by distillation and vacuum distillation to obtain branched synthetic fatty alcohol polyether A2.

[0053] Example 4:

[0054] Preparation of branched synthetic fatty alcohol polyether A3:

[0055] 100g of synthetic fatty alcohol polyether SAP-4, 5.2g of 40% sodium hydroxide aqueous solution, and 63g of toluene were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. The temperature was then raised to reflux temperature and maintained for 2.5h. 5g of trimethylolpropane was then slowly added dropwise to the system over 115min. After the addition was complete, the reaction was continued at reflux temperature for another 24h. Finally, the solids were removed by filtration, and the solvent toluene was removed by distillation and vacuum distillation to obtain branched synthetic fatty alcohol polyether A3.

[0056] Example 5:

[0057] Preparation of branched synthetic fatty alcohol polyether A4:

[0058] 100g of synthetic fatty alcohol polyether SAP-3, 1.1g of 50% cesium hydroxide aqueous solution, and 57g of toluene were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. The temperature was then raised to reflux temperature and maintained for 2 hours. 3-Trimethylolpropane was then slowly added dropwise to the system over 90 minutes. After the addition was complete, the reaction was continued at reflux temperature for 16 hours. Finally, the solids were removed by filtration, and the solvent toluene was removed by distillation and vacuum distillation to obtain branched synthetic fatty alcohol polyether A4.

[0059] Example 6:

[0060] Preparation of branched synthetic fatty alcohol polyether A5:

[0061] 100g of synthetic fatty alcohol polyether SAP-2, 2.1g of 40% potassium hydroxide aqueous solution, and 73g of xylene were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. The temperature was then raised to reflux temperature and maintained for 1.5h. 5g of trimethylolpropane was then slowly added dropwise to the system over 105min. After the addition was complete, the reaction was continued at reflux temperature for 13h. Finally, the solids were removed by filtration, and the solvent toluene was removed by distillation and vacuum distillation to obtain branched synthetic fatty alcohol polyether A5.

[0062] Example 7:

[0063] Preparation of polyether composition PC1:

[0064] At room temperature, 60 parts of branched synthetic fatty alcohol polyether A2 and 14 parts of secondary alcohol polyether (the initiator was a secondary alcohol with 4 carbon atoms, the average degree of polymerization of ethylene oxide was 1.2, and the average degree of polymerization of propylene oxide was 16.3) were added to a container, and stirring was started at 1200 rpm. Then, within 20 minutes, 5 parts of silica (with a specific surface area of ​​220 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 43% by methanol method), and dispersed for 2 hours, then passed through a homogenizer at a pressure of 6.5 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 20 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 8.8) and 1 part of synergist Dow 1266 were added to the "polyether-silica dispersion" at a speed of 1100 rpm, and mixed for 15 minutes to obtain the polyether composition PC1.

[0065] Comparative Example 1:

[0066] Preparation of polyether composition PC1-A: [using non-branched fatty alcohol polyether SAP-5]

[0067] At room temperature, 60 parts of synthetic fatty alcohol polyether SAP-5 and 14 parts of secondary alcohol polyether (initiator was a secondary alcohol with 4 carbon atoms, ethylene oxide had an average degree of polymerization of 1.2, and propylene oxide had an average degree of polymerization of 16.3) were added to a container, and stirring was started at 1200 rpm. Then, within 20 minutes, 5 parts of silica (with a specific surface area of ​​220 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 43% by methanol method), and dispersed for 2 hours, then passed through a homogenizer at a pressure of 6.5 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 20 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 8.8) and 1 part of synergist Dow 1266 were added to the "polyether-silica dispersion" at a speed of 1100 rpm, and mixed for 15 minutes to obtain the polyether composition PC1-A.

[0068] Comparative Example 2:

[0069] Preparation of polyether composition PC1-B: [Without secondary alcohol polyether]

[0070] At room temperature, 74 parts of branched synthetic fatty alcohol polyether A2 were added to a container, and stirring was started at 1200 rpm. Then, within 20 minutes, 5 parts of silica (with a specific surface area of ​​220 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 43% by methanol method), and dispersed for 2 hours, then passed through a homogenizer at a pressure of 6.5 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 20 parts of oleic acid polyether (average degree of polymerization of ethylene oxide of 8.8) and 1 part of synergist Dow 1266 were added to the "polyether-silica dispersion" at a speed of 1100 rpm, and mixed for 15 minutes to obtain the polyether composition PC1-B.

[0071] Comparative Example 3: [Ratio 3:1]

[0072] Preparation of polyether composition PC1-C:

[0073] At room temperature, 56 parts of branched synthetic fatty alcohol polyether A2 and 18 parts of secondary alcohol polyether (the initiator was a secondary alcohol with 4 carbon atoms, the average degree of polymerization of ethylene oxide was 1.2, and the average degree of polymerization of propylene oxide was 16.3) were added to a container, and stirring was started at 1200 rpm. Then, within 20 minutes, 5 parts of silica (with a specific surface area of ​​220 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 43% by methanol method), and dispersed for 2 hours, then passed through a homogenizer at a pressure of 6.5 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 20 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 8.8) and 1 part of synergist Dow 1266 were added to the "polyether-silica dispersion" at a speed of 1100 rpm, and mixed for 15 minutes to obtain the polyether composition PC1-C.

[0074] Comparative Example 4: [Ratio 17.5:1]

[0075] Preparation of polyether composition PC1-D:

[0076] At room temperature, 70 parts of branched synthetic fatty alcohol polyether A2 and 4 parts of secondary alcohol polyether (the initiator was a secondary alcohol with 4 carbon atoms, the average degree of polymerization of ethylene oxide was 1.2, and the average degree of polymerization of propylene oxide was 16.3) were added to a container, and stirring was started at 1200 rpm. Then, within 20 minutes, 5 parts of silica (with a specific surface area of ​​220 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 43% by methanol method), and dispersed for 2 hours, then passed through a homogenizer at a pressure of 6.5 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 20 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 8.8) and 1 part of synergist Dow 1266 were added to the "polyether-silica dispersion" at a speed of 1100 rpm, and mixed for 15 minutes to obtain the polyether composition PC1-D.

[0077] Comparative Example 5: [Without added silica]

[0078] Preparation of polyether composition PC1-D:

[0079] At room temperature, 64 parts of branched synthetic fatty alcohol polyether A2 and 15 parts of secondary alcohol polyether (the initiator is a secondary alcohol with 4 carbon atoms, the average degree of polymerization of ethylene oxide is 1.2, and the average degree of polymerization of propylene oxide is 16.3) were added to a container, and stirring was started at 1200 rpm. Then, at 1100 rpm, 20 parts of oleic acid polyether (the average degree of polymerization of ethylene oxide is 8.8) and 1 part of synergist Dow 1266 were added to the polyether-silica dispersion and mixed for 15 min to obtain the polyether composition PC1-D.

[0080] Comparative Example 6: [Silica with a very high hydrophobic value]

[0081] Preparation of polyether composition PC1-E:

[0082] At room temperature, 60 parts of branched synthetic fatty alcohol polyether A2 and 14 parts of secondary alcohol polyether (the initiator was a secondary alcohol with 4 carbon atoms, the average degree of polymerization of ethylene oxide was 1.2, and the average degree of polymerization of propylene oxide was 16.3) were added to a container, and stirring was started at 1200 rpm. Then, within 20 minutes, 5 parts of silica (with a specific surface area of ​​220 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 72% by methanol method), and dispersed for 2 hours, then passed through a homogenizer at a pressure of 6.5 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 20 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 8.8) and 1 part of synergist Dow 1266 were added to the "polyether-silica dispersion" at a speed of 1100 rpm, and mixed for 15 minutes to obtain the polyether composition PC1-E.

[0083] Example 8:

[0084] Preparation of polyether composition PC2:

[0085] At room temperature, 80 parts of branched synthetic fatty alcohol polyether A4 and 6 parts of secondary alcohol polyether (the initiator was a secondary alcohol with 8 carbon atoms, the average degree of polymerization of ethylene oxide was 9.6, and the average degree of polymerization of propylene oxide was 24.6) were added to a container, and stirring was started at 2800 rpm. Then, within 6 minutes, 5 parts of silica (with a specific surface area of ​​380 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 58% by methanol method), and dispersed for 1.2h, then passed through a homogenizer at a pressure of 9.6MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 6 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 6.2) and 3 parts of Dow 7600 synergist were added to the "polyether-silica dispersion" at a speed of 1900rpm, and mixed for 28min to obtain the polyether composition PC2.

[0086] Example 9:

[0087] Preparation of polyether composition PC3:

[0088] At room temperature, 72 parts of branched synthetic fatty alcohol polyether A5 and 7.8 parts of secondary alcohol polyether (the initiator was a secondary alcohol with 22 carbon atoms, the average degree of polymerization of ethylene oxide was 6.8, and the average degree of polymerization of propylene oxide was 5.6) were added to a container, and stirring was started at 1350 rpm. Then, within 28 minutes, 10 parts of silica (with a specific surface area of ​​70 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 48% by methanol method), and dispersed for 3 hours, then passed through a homogenizer at a pressure of 3.5 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 10 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 14) and 0.2 parts of Wacker Chemie SD850 were added to the "polyether-silica dispersion" at a speed of 600 rpm, and mixed for 12 minutes to obtain the polyether composition PC3.

[0089] Comparative Example 7: (using primary alcohol polyether instead of secondary alcohol polyether)

[0090] Preparation of polyether composition PC3-A:

[0091] At room temperature, 72 parts of branched synthetic fatty alcohol polyether A5 and 7.8 parts of primary alcohol polyether (initiator was a primary alcohol with 22 carbon atoms, ethylene oxide had an average degree of polymerization of 6.8, and propylene oxide had an average degree of polymerization of 5.6) were added to a container, and stirring was started at 1350 rpm. Then, within 28 minutes, 10 parts of silica (with a specific surface area of ​​70 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 48% by methanol method), and dispersed for 3 hours, then passed through a homogenizer at a pressure of 3.5 MPa to further disperse the silica particles, thus obtaining a "polyether-silica dispersion"; finally, 10 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 14) and 0.2 parts of Wacker Chemie SD850 were added to the "polyether-silica dispersion" at a speed of 600 rpm, and mixed for 12 minutes to obtain the polyether composition PC3-A.

[0092] Example 10:

[0093] Preparation of polyether composition PC4:

[0094] At room temperature, 68 parts of branched synthetic fatty alcohol polyether A1 and 9.7 parts of secondary alcohol polyether (the initiator was a secondary alcohol with 18 carbon atoms, the average degree of polymerization of ethylene oxide was 5.3, and the average degree of polymerization of propylene oxide was 22.7) were added to a container, and stirring was started at 2550 rpm. Then, within 15 minutes, 7.9 parts of silica (with a specific surface area of ​​110 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 52% by methanol method), and dispersed for another 2.5h, the silica particles were further dispersed by a homogenizer at a pressure of 6MPa to obtain a "polyether-silica dispersion". Finally, 13 parts of oleic acid polyether (average degree of polymerization of ethylene oxide of 10.5) and 1.4 parts of synergist Wacker Chemie SD860 were added to the "polyether-silica dispersion" at a speed of 1400rpm and mixed for 15min to obtain the polyether composition PC4.

[0095] Example 11:

[0096] Preparation of polyether composition PC5:

[0097] At room temperature, 79 parts of branched synthetic fatty alcohol polyether A3 and 6.7 parts of secondary alcohol polyether (the initiator was a secondary alcohol with 14 carbon atoms, the average degree of polymerization of ethylene oxide was 6.2, and the average degree of polymerization of propylene oxide was 16.8) were added to a container, and stirring was started at 2200 rpm. Then, within 25 minutes, 4.5 parts of silica (with a specific surface area of ​​320 m²) were added to the reactor. 2 / g, treated with hexamethyldisilazane (hydrophobicity value of 43% by methanol method), and dispersed for another 1.8h, the silica particles were further dispersed by a homogenizer at a pressure of 4MPa to obtain a "polyether-silica dispersion". Finally, 9 parts of oleic acid polyether (average degree of polymerization of ethylene oxide is 12.3) and 0.8 parts of synergist DC544 from Dow Chemical Company were added to the "polyether-silica dispersion" at a speed of 1750rpm and mixed for 15min to obtain the polyether composition PC5.

[0098] Comparative Example 8:

[0099] CPC, a mineral oil defoamer prepared from end-capped polyether according to Example 1 of patent CN101811007.

[0100] Performance testing

[0101] 1. Comparison of foam performance control:

[0102] Weigh 200g of commercially available water-based paint, 100g of deionized water, and 0.2g of the test sample into a container. Disperse the mixture at 1500rpm for 5 minutes. Immediately after dispersion, pour a portion of the dispersion into a graduated cylinder and read the volume V. Weigh the dispersion into the graduated cylinder and record the weight M. The dispersion density ρ is then calculated using the following formula:

[0103] ρ(g / mL)=M / V×100%

[0104] 2. Wettability test:

[0105] Take a small amount of the dispersion liquid that has been tested for dispersion density and drop it onto black and white paper. Use a 75-micron wet film preparer to scrape it evenly at a constant speed and observe the state of the dispersion liquid on the glass plate (the state of pinholes). The pinholes are expressed as 1 mm per square centimeter of dry film.

[0106] 3. Centrifugal stability test:

[0107] Take 8 ml of sample and place it in a 10 ml glass centrifuge tube. Centrifuge at 3000 rpm for 15 min and observe the precipitation or sedimentation on the surface and bottom of the centrifuge tube.

[0108] Table 1. Results of sample dispersion density, wettability, and stability tests.

[0109] Test sample High-speed dispersion density / g / mL Wettability / each Centrifugal stability test PC1 1.4423 1 No precipitation, no sedimentation PC1-A 1.4319 4 No precipitation, no sedimentation PC1-B 1.4002 0 No precipitation, no sedimentation PC1-C 1.4607 2 No precipitation, no sedimentation PC1-D 1.3923 1 No precipitation, no sedimentation PC1-E 1.4415 3 There is 1ml of viscous sediment at the bottom. PC-2 1.4458 1 No precipitation, no sedimentation PC-3 1.4528 1 No precipitation, no sedimentation PC-3A 1.4653 6 No precipitation, no sedimentation PC-4 1.4437 0 No precipitation, no sedimentation PC-5 1.4618 0 No precipitation, no sedimentation CPC 1.4137 4 Polyether precipitate at the bottom

[0110] The test data above shows that:

[0111] The samples PC1 to PC5 of the patented invention produced significantly fewer pinholes in the coating compared to the comparative sample, and the coating density after high-speed dispersion was also relatively high.

[0112] Through PC1 and PC1-A~C, a synergistic effect exists between secondary alcohol polyethers and branched synthetic fatty alcohol polyethers. The presence of secondary alcohol polyethers is beneficial to improving wetting properties, but it weakens the defoaming effect. By comparing PC3 and PC3-A, it can be found that the synergistic effect between secondary alcohol polyethers and branched synthetic fatty alcohol polyethers is much greater than that between primary alcohol polyethers and branched synthetic fatty alcohol polyethers. Primary alcohol polyethers affect wetting properties.

[0113] By comparing PC1 with PC1-D to E, it can be found that the hydrophobicity of silica cannot be too high, as this will affect stability. However, silica is indispensable as an antifoaming agent.

Claims

1. A polyether composition, characterized in that, The raw materials for preparing the polyether composition are branched synthetic fatty alcohol polyether A, secondary alcohol polyether B, oleic acid polyether C, silicon dioxide D and synergist E; A, branched synthetic fatty alcohol polyether The branched synthetic fatty alcohol polyether is synthesized from synthetic fatty alcohol polyether and trimethylolpropane under alkaline conditions; The synthetic fatty alcohol polyether is prepared by addition reaction of monofunctional synthetic fatty alcohol with carbon atom number of 6-30 as starting agent and ethylene oxide EO and propylene oxide PO, and its general structure is as follows: RO (EO) a (PO) b H (Ⅰ) In formula (I), R is the functional group in polyether starting agent; subscripts a and b are the polymerization degrees of EO and PO respectively, a is 0 or 1-10, and b is 10-40; The method for preparing the branched synthetic fatty alcohol polyether is as follows: In a reactor equipped with a stirrer, a thermometer and a condenser, the required amount of synthetic fatty alcohol polyether, aqueous catalyst solution and solvent are added, then the temperature is raised to reflux temperature and kept for 1-3 h; then trimethylolpropane is slowly added dropwise to the system within 20-120 min, after the dropwise addition is completed, the reaction is continued at reflux temperature for 6-24 h, finally the solid is removed by filtration, and then toluene is removed by distillation and vacuum distillation to obtain the branched synthetic fatty alcohol polyether; The amount of the branched synthetic fatty alcohol polyether is 60-80% of the total mass of the polyether composition; B, secondary alcohol polyether The secondary alcohol polyether is prepared by addition reaction of monohydric alcohol with active hydroxyl group at secondary position and carbon atom number of 4-22 as starting agent and ethylene oxide EO and propylene oxide PO; The general structure of the secondary alcohol polyether is as follows: R 1 O(EO) c (PO) d H (Ⅱ) In formula (II), subscripts c and d are the polymerization degrees of EO and PO respectively, c is 1-10, and d is 5-25; The amount of the secondary alcohol polyether is 5-15% of the total mass of the polyether composition; C, oleic acid polyether The oleic acid polyether is used to emulsify and disperse the polyether composition, and its general structure is as follows: C 17 H 33 COO(EO) e OCH 33 C 17 In formula (III), subscript e is the polymerization degree of ethylene oxide EO, which is 6-15; The amount of the oleic acid polyether is 5-20% of the total mass of the polyether composition; D, silicon dioxide The silica has a specific surface area of 60 to 400 m 2 / g precipitated hydrophobic silica, the hydrophobic treatment agent is hexamethyldisilazane, and the methanol method hydrophobic value is 40 to 60%. The amount of the silicon dioxide is 3-10% of the total mass of the polyether composition; E, synergist The synergist is selected from 1247, 1266, DC544, 7600 and 7800 of Dow Corning Company and SD850, SD 860 and Pulpsil 235C of Wacker Company, and its amount is 0.1-3% of the total mass of the polyether composition; The method for preparing the polyether composition is as follows: At room temperature, the branched synthetic fatty alcohol polyether and the secondary alcohol polyether are put into a container, stirring is started at a rotation speed of 1000-3000 rpm, then the silicon dioxide is added to the reactor within 5-30 min, and the dispersion is continued for 1-3 h, then the "polyether-silicon dioxide dispersion" is further treated by a homogenizer with a pressure of 3-10 MPa to make the silicon dioxide particles disperse, and finally the oleic acid polyether and the synergist are added to the "polyether-silicon dioxide dispersion" at a rotation speed of 500-2000 rpm, and mixed for 10-30 min to obtain the product of the present application.

2. A polyether composition according to claim 1, characterized in that The mass ratio of the main raw material of the branched synthetic fatty alcohol polyether, the synthetic fatty alcohol polyether, and trimethylolpropane is 5:1-35:

1.

3. A polyether composition according to claim 1, wherein The catalyst for preparing the branched synthetic fatty alcohol polyether is selected from sodium hydroxide, potassium hydroxide, and cesium hydroxide, and the amount is 0.5-2% of the total mass of the synthetic fatty alcohol polyether and trimethylolpropane, and the catalyst is used in the form of an aqueous solution, and the mass percentage concentration of the aqueous solution is 30-50%.

4. The polyether composition of claim 1, wherein The solvent for preparing the branched synthetic fatty alcohol polyether is one or a mixture of toluene and xylene, and the amount is 50-70% of the total mass of the synthetic fatty alcohol polyether and trimethylolpropane.

5. The polyether composition of claim 1, wherein The mass ratio of the raw material of the branched synthetic fatty alcohol polyether to the secondary alcohol polyether in the preparation of the polyether composition is 15:1-4:1.