Star-shaped polyether silicone copolymer, and preparation method and application thereof

Abstract

The application belongs to the technical field of polyether organosilicon copolymer preparation, and relates to a star-shaped polyether organosilicon copolymer, a preparation method and application thereof. Dimethylcyclosiloxane and octamethylcyclotetrasiloxane are subjected to ring-opening polymerization, crosslinking with 1,5-hexadiene to prepare a hydrogen-containing polymethylsiloxane skeleton, 2,4,7,9-tetramethyl-5-decyne-4,7-diol is used as raw material, ring-opening polymerization with propylene oxide to obtain an alkyne diol ether intermediate, and then the star-shaped polyether organosilicon copolymer is prepared by the silicon-hydrogen addition of the hydrogen-containing polymethylsiloxane, which can be used as an active ingredient of a defoaming agent. Compared with linear polyether, the star-shaped branched structure diversifies the van der Waals force, hydrogen bond and other forces, can more quickly destroy the stability of the foam liquid film, and realizes rapid defoaming.

Description

Technical Field

[0001] This invention relates to the field of polyether silicone copolymer preparation technology, and in particular to a star-shaped polyether silicone copolymer, its preparation method and application. Background Technology

[0002] Linear polyether silicone copolymers are a class of high-performance materials formed by combining polyether segments with siloxane backbones. This combination creates new materials that combine the advantages of both, such as self-emulsifying defoamers and high-efficiency foam levelers, which are widely used in the chemical industry. However, their performance is limited by the molecular chain mobility of the linear structure. Introducing star-shaped or comb-shaped branched structures can enhance their functionality. Star-shaped structures, due to their unique topological morphology, exhibit significant advantages in reducing solution viscosity, improving surface activity, and regulating phase behavior.

[0003] Chinese patent application CN104448323A discloses a star-shaped comb-like polyether silicone copolymer and its preparation method. In this copolymer, a diene and heptamethyltrisiloxane are linked by silicon-carbon bonds to form branching points. Polysiloxane side chains are introduced, with Si-H-Si chains connecting the branching points. The side chains are polyether chains, linked to the polysiloxane chains by silicon-carbon bonds. In this structure, the Si-H bonds are prone to hydrolysis, dehydrogenation condensation, or hydrosilylation side reactions at high temperatures or in the presence of Lewis acid or alkali catalysts. Alternatively, silanol groups may be generated in oxidizing environments, initiating chain segment degradation or cross-linking, thus disrupting the copolymer's molecular structure and affecting its surface activity, defoaming properties, or mechanical properties. Summary of the Invention

[0004] This invention aims to provide a star-shaped polyether silicone copolymer, its preparation method, and its application. This star-shaped polyether silicone copolymer is the active ingredient in water-based coating defoamers. The silicone main chain branches polyether multi-arm segments, which dynamically extend and adsorb onto the surfaces of multiple bubbles, rapidly disrupting the elasticity of the liquid film and increasing the defoaming speed. The star-shaped branched structure reduces chain entanglement and lowers the system viscosity, making it easier to penetrate to the foam interface and form a durable barrier at the interface, inhibiting foam regeneration.

[0005] To achieve the above objectives, the present invention provides a star-shaped polyether silicone copolymer, the structure of which is shown below:

[0006]

[0007] Where m takes the value of an integer between 5 and 10; α is 1, and β takes the value of an integer between 2 and 5.

[0008] This invention also provides a method for preparing a star-shaped polyether organosilicon copolymer, comprising:

[0009] Step S1: Disperse 2,4,7,9-tetramethyl-5-decyn-4,7-diol in the first solvent, add propylene oxide and the first catalyst, and after the reaction is complete, add acetic acid, filter, and obtain the acetylenic diol ether intermediate;

[0010] Step S2: Disperse dimethylcyclosiloxane and octamethylcyclotetrasiloxane in a second solvent, add a second catalyst, and after a first reaction, add 1,5-hexadiene, a third catalyst, and triethylamine, and after a second reaction, obtain hydrogen-containing polymethylsiloxane;

[0011] Step S3: Add the acetylacetonate diol ether intermediate to the hydrogen-containing polymethylsiloxane, add a third catalyst, and react to obtain a star-shaped polyether organosilicon copolymer.

[0012] Preferably, in step S1, the first solvent is any one or more of tetrahydrofuran, toluene, and dioxane.

[0013] Preferably, in step S1, the first catalyst is any one or more of sodium hydroxide and potassium hydroxide.

[0014] Preferably, in step S1, the reaction temperature is 80–100°C and the reaction time is 4–6 hours.

[0015] Preferably, in step S1, the mass ratio of 2,4,7,9-tetramethyl-5-decyn-4,7-diol, the first solvent, propylene oxide, and the first catalyst is 1:(3-5):(2.5-5.5):(0.01-0.03).

[0016] Preferably, in step S2, the second solvent is any one or more of toluene and xylene.

[0017] Preferably, the second catalyst is concentrated sulfuric acid.

[0018] Preferably, in step S2, the temperature of the first reaction is 40–60°C, and the reaction time is 6–8 hours.

[0019] Preferably, in step S2, the third catalyst is chloroplatinic acid.

[0020] Preferably, in step S2, the temperature of the second reaction is 60-80°C, and the reaction time is 2-3 hours.

[0021] Preferably, in step S2, the mass ratio of dimethylcyclosiloxane, octamethylcyclotetrasiloxane, the second solvent, the second catalyst, 1,5-hexadiene, the third catalyst, and triethylamine is 1:(12.3-24.6):(30-50):(0.05-0.1):(5-12):(0.025-0.05):(0.1-0.15).

[0022] Preferably, in step S3, the reaction temperature is 60–80°C and the reaction time is 4–6 hours.

[0023] Preferably, in step S3, the mass ratio of the hydrogen-containing polymethylsiloxane, the acetylacetonate intermediate, and the third catalyst is 1:(1.25-2.55):(0.00025-0.00035).

[0024] This invention also provides the application of a star-shaped polyether silicone copolymer in the preparation of defoamers.

[0025] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0026] (1) In this invention, octamethylcyclotetrasiloxane and dimethylcyclosiloxane are ring-opened polymerized, and 1,5-hexadienyl is used as a crosslinking agent to prepare a hydrogen-containing polymethylsiloxane skeleton crosslinked with siloxane and carbon chain. The low surface energy of siloxane and the hydrophobicity of carbon chain combine to make the product have stronger defoaming ability and durability in aqueous system. The presence of carbon chain can reduce intermolecular forces and improve the fluidity of lubricant. Acrylene glycol ether and siloxane are introduced into polyether segment through hydrosilylation to obtain star-shaped polyether organosilicon copolymer.

[0027] (2) The active ingredient of the star-shaped polyether organosilicon copolymer waterborne coating defoamer prepared in this invention has multiple branches in its star structure compared with that of linear polyether. The intermolecular forces such as van der Waals forces and hydrogen bonds are diversified. When in contact with foam, it can destroy the stability of the foam liquid film more quickly and achieve rapid defoaming. The multiple branches in the structure increase the flexibility and fluidity of polymer molecules, which is conducive to its diffusion in the foam system. That is, when the defoamer molecules diffuse into the foam liquid film, they will change the local composition and properties of the liquid film, reduce the surface viscosity and elasticity of the liquid film, and make the foam easier to break. In contrast, the structure of linear polyether defoamer has poor diffusion performance and requires more time to reach an effective concentration in the foam liquid film to achieve defoaming. Attached Figure Description

[0028] Figure 1 This is the synthetic route for alkynyl diol ether intermediates.

[0029] Figure 2 This is the synthetic route for star-shaped polyether organosilicon copolymers.

[0030] Figure 3 This is a picture of a star-shaped polyether silicone copolymer defoamer. Detailed Implementation

[0031] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0032] Unless otherwise specified, all reagents and equipment used in the following examples were purchased from commercial channels.

[0033] Example 1

[0034] A star-shaped polyether silicone copolymer, the preparation method of which includes:

[0035] Step S1: 10g of 2,4,7,9-tetramethyl-5-decyn-4,7-diol was dispersed in 30g of dioxane, 25g of propylene oxide and 0.1g of sodium hydroxide were added, and the mixture was reacted at 80℃ for 6h. Acetic acid was added to neutralize the excess sodium hydroxide, and the mixture was filtered to obtain the acetylinyl diol ether intermediate, as shown below. Figure 1 As shown.

[0036] Step S2: Disperse 1g of dimethylcyclosiloxane and 12.3g of octamethylcyclotetrasiloxane in 30g of toluene, add 0.05g of concentrated sulfuric acid, react at 40℃ for 8h, add 5g of 1,5-hexadiene, 0.025g of chloroplatinic acid and 0.1g of triethylamine, react at 60℃ for 3h to obtain hydrogen-containing polymethylsiloxane.

[0037] Step S3: Add 10g of acetylacetonate diol ether intermediate to 12.5g of hydrogen-containing polymethylsiloxane, add 0.0025g of chloroplatinic acid, and react to obtain a star-shaped polyether organosilicon copolymer, such as... Figure 2 As shown.

[0038] Example 2

[0039] A star-shaped polyether silicone copolymer, the preparation method of which includes:

[0040] Step S1: 10g of 2,4,7,9-tetramethyl-5-decyn-4,7-diol was dispersed in 40g of tetrahydrofuran, 40g of propylene oxide and 0.2g of potassium hydroxide were added, and the mixture was reacted at 90℃ for 5h. Acetic acid was added to neutralize excess potassium hydroxide, and the mixture was filtered to obtain the acetylacetonate intermediate, as shown below. Figure 1 As shown.

[0041] Step S2: Disperse 1g of dimethylcyclosiloxane and 18.5g of octamethylcyclotetrasiloxane in 40g of xylene, add 0.1g of concentrated sulfuric acid, react at 50℃ for 7h, add 8g of 1,5-hexadiene, 0.04g of chloroplatinic acid and 0.15g of triethylamine, react at 70℃ for 2.5h to obtain hydrogen-containing polymethylsiloxane.

[0042] Step S3: Add 10g of acetylacetonate diol ether intermediate to 17.5g of hydrogen-containing polymethylsiloxane, add 0.003g of chloroplatinic acid, and react to obtain a star-shaped polyether organosilicon copolymer, such as... Figure 2 As shown.

[0043] Example 3

[0044] A star-shaped polyether silicone copolymer, the preparation method of which includes:

[0045] Step S1: Disperse 10g of 2,4,7,9-tetramethyl-5-decyn-4,7-diol in 50g of toluene, add 55g of propylene oxide and 0.3g of sodium hydroxide, react at 100℃ for 4h, add acetic acid to neutralize excess sodium hydroxide, filter, and obtain the acetylacetonate intermediate, as shown below. Figure 1 As shown.

[0046] Step S2: Disperse 1g of dimethylcyclosiloxane and 24.6g of octamethylcyclotetrasiloxane in 50g of toluene, add 0.1g of concentrated sulfuric acid, react at 60℃ for 6h, add 12g of 1,5-hexadiene, 0.05g of chloroplatinic acid and 0.15g of triethylamine, react at 80℃ for 2h to obtain hydrogen-containing polymethylsiloxane.

[0047] Step S3: Add 10g of acetylacetonate diol ether intermediate to 25.5g of hydrogen-containing polymethylsiloxane, add 0.0035g of chloroplatinic acid, and react to obtain a star-shaped polyether organosilicon copolymer, such as... Figure 2 As shown.

[0048] Example 4

[0049] An antifoaming agent, the preparation method of which includes:

[0050] The star-shaped polyether silicone copolymer prepared in Example 1 was dispersed in propylene glycol, Span-80 and deionized water were added, and homogenization was performed to obtain an aqueous defoamer emulsion. Polyvinyl alcohol, sodium benzoate, and attapulgite were added, and the mixture was stirred to obtain the star-shaped polyether silicone copolymer defoamer. Figure 3 As shown.

[0051] Example 5

[0052] An antifoaming agent, the preparation method of which includes:

[0053] The star-shaped polyether silicone copolymer prepared in Example 2 was dispersed in propylene glycol, Span-80 and deionized water were added, and homogenization was performed to obtain an aqueous defoamer emulsion. Polyvinyl alcohol, sodium benzoate, and attapulgite were added, and the mixture was stirred to obtain the star-shaped polyether silicone copolymer defoamer. Figure 3 As shown.

[0054] Example 6

[0055] An antifoaming agent, the preparation method of which includes:

[0056] The star-shaped polyether silicone copolymer prepared in Example 3 was dispersed in propylene glycol, Span-80 and deionized water were added, and homogenization was performed to obtain an aqueous defoamer emulsion. Polyvinyl alcohol, sodium benzoate, and attapulgite were added and stirred to obtain the star-shaped polyether silicone copolymer defoamer. Figure 3 As shown.

[0057] Comparative Example 1

[0058] A commercially available silicone defoamer, model number TEGO-902W (BASF).

[0059] Comparative Example 2

[0060] A commercially available silicone defoamer, model number BYK-022 (BYK, Germany).

[0061] Performance testing:

[0062] (1) Defoaming efficiency test: 50 mL of foaming liquid was measured into a 100 mL stoppered graduated cylinder, and 1 mL of defoaming agent was added into the stoppered graduated cylinder with a pipette. The cylinder was shaken vigorously 30 times at room temperature and allowed to stand. At the same time, a stopwatch was started to record the time required for the foam volume to be less than 5 mL.

[0063] (2) Thermal stability test:

[0064] Static thermal stability test: The defoamers prepared in Examples 4 to 6 were placed in a high-temperature aging chamber and left to stand at 150°C for 24 hours. Their appearance was observed and their defoaming efficiency was tested using the method in (1).

[0065] Dynamic high-temperature defoaming test: The foaming liquid was added to the autoclave and continuously aerated at 150℃ and 5MPa. The time required for the foam height to be less than 5mL was recorded.

[0066] (3) Evaluation of coating defects: The defoamers of Examples 4 to 6 and Comparative Examples 1 and 2 were mixed with waterborne acrylic coating, waterborne polyurethane coating and waterborne epoxy resin coating respectively, applied to glass substrates and dried at 50 to 60°C for 1 to 2 hours. The coating surface was then observed for peeling, pinholes, cracks and shrinkage cavities.

[0067] Table 1 Defoaming efficiency test data

[0068]

[0069] As shown in Table 1, the defoamers prepared in Examples 4 to 6 all reduced the foam height from 50 mL to below 5 mL within 15 seconds, while the defoamer in Comparative Example 1 reduced the foam height from 50 mL to below 5 mL in 31 seconds, and the defoamer in Comparative Example 2 reduced the foam height from 50 mL to below 5 mL in 28 seconds. The experiments demonstrate that the defoamers prepared in Examples 4 to 6 have excellent defoaming performance.

[0070] Table 2 Thermal stability test data

[0071]

[0072]

[0073] As shown in Table 2, after adding the defoamers of Examples 4 to 6 and Comparative Examples 1 to 2, and placing them at high temperature for 24 hours, the morphology and appearance of all samples remained unchanged, and no layering or thickening occurred. Furthermore, the defoamers could reduce the foam from 50 mL to below 5 mL within 15 seconds. Under conditions of 150°C and 5 MPa, when continuously aerated until the foam height reached 50 mL, the defoamers prepared in Examples 4 to 6 reduced the foam from 50 mL to below 5 mL within 20 seconds, while Comparative Example 1 required 47 seconds and Comparative Example 2 required 49 seconds.

[0074] Table 3. Coating Defect Assessment Test Results

[0075]

[0076] As shown in Table 3, none of the three coatings with added Examples 4 to 6 exhibited peeling or cracking, and the coatings were smooth and free of pinholes and craters. The coatings with added defoamers from Comparative Examples 1 and 2 also showed no peeling, but some individual coating surfaces had pinholes and craters. The experiment demonstrates that the defoamers from Examples 4 to 6 have good compatibility and dispersibility with the coatings. When added to the coatings, they effectively defoam without affecting the coating's curing, appearance, or performance.

[0077] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A star-shaped polyether silicone copolymer, characterized in that, The structure of the star-shaped polyether silicone copolymer is shown below: Where m takes the value of an integer between 5 and 10, α is 1, and β takes the value of an integer between 2 and 5.

2. The method for preparing a star-shaped polyether organosilicon copolymer according to claim 1, characterized in that, include: Step S1: 2,4,7,9-Tetramethyl-5-decyn-4,7-diol is dispersed in the first solvent, propylene oxide and the first catalyst are added, acetic acid is added after the reaction is completed, and the mixture is filtered to obtain the acetylacetonate intermediate. Step S2: Disperse dimethylcyclosiloxane and octamethylcyclotetrasiloxane in a second solvent, add a second catalyst, and after a first reaction, add 1,5-hexadiene, a third catalyst, and triethylamine, and after a second reaction, obtain hydrogen-containing polymethylsiloxane; Step S3: Add the acetylacetonate diol ether intermediate to the hydrogen-containing polymethylsiloxane, add a third catalyst, and react to obtain a star-shaped polyether organosilicon copolymer.

3. The method for preparing a star-shaped polyether organosilicon copolymer according to claim 2, characterized in that, In step S1, the first solvent is any one or more of tetrahydrofuran, toluene, and dioxane; the first catalyst is any one or more of sodium hydroxide and potassium hydroxide; the reaction temperature is 80–100°C, and the reaction time is 4–6 h.

4. The method for preparing a star-shaped polyether organosilicon copolymer according to claim 2, characterized in that, In step S1, the mass ratio of 2,4,7,9-tetramethyl-5-decyn-4,7-diol, the first solvent, propylene oxide, and the first catalyst is 1:(3-5):(2.5-5.5):(0.01-0.03).

5. The method for preparing a star-shaped polyether organosilicon copolymer according to claim 2, characterized in that, In step S2, the second solvent is any one or more of toluene and xylene; the second catalyst is concentrated sulfuric acid.

6. The method for preparing a star-shaped polyether organosilicon copolymer according to claim 2, characterized in that, In step S2, the temperature of the first reaction is 40-60°C and the reaction time is 6-8 hours; the third catalyst is chloroplatinic acid; the temperature of the second reaction is 60-80°C and the reaction time is 2-3 hours.

7. The method for preparing a star-shaped polyether organosilicon copolymer according to claim 2, characterized in that, In step S2, the mass ratio of dimethylcyclosiloxane, octamethylcyclotetrasiloxane, the second solvent, the second catalyst, 1,5-hexadiene, the third catalyst, and triethylamine is 1:(12.3-24.6):(30-50):(0.05-0.1):(5-12):(0.025-0.05):(0.1-0.15).

8. The method for preparing a star-shaped polyether organosilicon copolymer according to claim 2, characterized in that, In step S3, the reaction temperature is 60–80°C and the reaction time is 4–6 hours.

9. The method for preparing a star-shaped polyether organosilicon copolymer according to claim 2, characterized in that, In step S3, the mass ratio of the hydrogen-containing polymethylsiloxane, the alkynyl glycol ether intermediate, and the third catalyst is 1:(1.25-2.55):(0.00025-0.00035).

10. The application of the star-shaped polyether silicone copolymer according to claim 1 in the preparation of defoamers.

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