Polyether-modified polyacrylate defoaming agent and preparation method thereof

Abstract

The application discloses a polyether modified polyacrylate defoaming agent, which is copolymerized by allyl polyether and acrylate and methacrylate, and has the following general formula: wherein x, y and z are positive integers of 1-300, a and b are positive integers of 1-100; R1 and R2 are H, alkyl of 1-33C, hydroxyalkyl or cycloalkyl, and R3 is H, alkyl of 1-18C or alkylacyl of 1-18C. The polyether modified polyacrylate has a molecular weight of 10000-70000, excellent defoaming efficiency and compatibility, and is particularly suitable for defoaming and defoaming of solvent type coatings such as alkyd resin, polyurethane resin and polyester resin, and has good popularization value and market prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of defoaming agents, and particularly relates to a polyether modified polyacrylate defoaming agent and a preparation method thereof. TECHNICAL BACKGROUND

[0002] Foam is a stable dispersion of air in a liquid medium. In general, a pure liquid will not form a stable foam. The air bubbles formed by stirring a pure liquid are less dense than the liquid, and the bubbles gradually move to the surface, where they burst and escape until the bubbles disappear. Only when a surface-active substance is mixed into the liquid can a stable foam be formed. The surface-active substance mixed in will increase the elastic modulus of the liquid bubble membrane, thereby obtaining a stable structure.

[0003] In the prior art, the methods for eliminating the foam in a liquid system mainly include physical defoaming methods and chemical defoaming methods. The commonly used physical defoaming methods mainly include thermodynamic methods, ultrasonic methods, electric methods, vacuum methods and mechanical methods, which mainly use mechanical equipment to exert physical effects on the foam to make the foam lose stability and burst to achieve the effect of defoaming. The disadvantage of the physical defoaming methods is that they depend on mechanical equipment and can only eliminate a small amount of bubbles, and the defoaming efficiency is relatively low. The chemical defoaming method is to add a chemical reagent to the foam base liquid to change the properties of the foaming agent, thereby achieving the purpose of defoaming. The reagent used is a defoaming agent. The chemical defoaming method has the advantages of simple construction and high defoaming efficiency.

[0004] The existing defoaming agents on the market can be divided into mineral oil defoaming agents, polyether defoaming agents, silicone defoaming agents and polyacrylate defoaming agents according to the components. The mineral oil defoaming agent has good compatibility, large dosage tolerance and is not easy to produce shrinkage; the polyether defoaming agent has outstanding foam suppression performance and general defoaming power; the silicone defoaming agent has high defoaming efficiency but poor foam suppression performance; and the polyacrylate defoaming agent has relatively good defoaming power and compatibility but poor foam suppression performance than the polyether defoaming agent.

[0005] In the prior art, there are few defoaming agents that can balance the three properties of defoaming, foam suppression and compatibility. In order to balance these properties, polyether modified silicone defoaming agents, fluorine modified silicone defoaming agents and polyether modified silicone defoaming agents have been developed.

[0006] CN 102027077 A (2011) describes a random defoaming agent for solvent-based coatings. The invention synthesizes a random defoaming agent for solvent-based transparent wood coatings by copolymerizing a vinyl ether monomer with an acrylate monomer.

[0007] CN 107417847 A (2017) describes a fluorine modified polyacrylate defoaming agent and a preparation method thereof. The invention copolymerizes acrylate, methacrylate and fluorine-containing methacrylate monomers, which can effectively reduce the surface tension and improve the defoaming effect of the defoaming agent.

[0008] CN 107652389 A (2018) describes an acrylate antifoaming agent, which is copolymerized with isobornyl methacrylate, methacrylic acid and glycidyl methacrylate using propylene glycol methyl ether acetate as a solvent, and is used for defoaming and antifoaming of alkyd resin and polyester.

[0009] CN 111040504 A (2020) describes a solvent-based coating defoaming agent and a preparation method, which is prepared by solution polymerization of modified acrylate and vinyl-containing silicone oil under the initiation of an initiator, and is mainly used for solvent-based epoxy and acrylic coatings, has fast defoaming and long foam suppression time, and makes the coating surface have better waterproof and anticorrosive properties.

[0010] CN 111484630 A (2020) describes a polymer emulsion type defoaming agent and a preparation method thereof, which synthesizes active substances from acrylate and allyl polyether as monomers, and mixes with filler particles, water, thickening agent and the like to form an emulsion type defoaming agent, solving a series of problems such as oil floating, precipitation and demulsification caused by emulsifiers in traditional organic silicon emulsion type defoaming agents.

[0011] CN 114452686 A (2022) describes a solvent-free polyacrylate defoaming agent, which is synthesized by using acrylate, methacrylate and vinyl ether as comonomers and high-boiling organic solvent as carrier, and has the advantages of compatibility with common polyurethane raw materials, no influence on the appearance transparency of the material when used in transparent polyurethane material, solving the material fogging and whitening phenomenon caused by the addition of defoaming agent in the polyurethane system, and no volatile release, safe and environmentally friendly.

[0012] In the prior art, polyacrylate defoaming agents synthesized with solvents as organic carriers release volatile components into the environment during synthesis, and products also have negative effects on the environment due to the presence of organic solvents; those synthesized with high-boiling solvents will precipitate from the system over time after use, which can seriously affect the performance of the coating. Organic silicon and fluorine-containing defoaming agents can easily produce shrinkage holes when used improperly due to their very low surface tension.

SUMMARY

[0013] To overcome the shortcomings of the prior art, the present application provides a polyether modified polyacrylate defoaming agent and a preparation method thereof, which uses allyl polyether as a substrate and synthesizes by dropping a mixed solution of acrylate, methacrylate and initiator, has the characteristics of simple process, high synthesis efficiency, low VOC of product, safety and environmental protection, etc.

[0014] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0015] A polyether modified polyacrylate defoamer is composed of the following components: the polyether modified polyacrylate defoamer is prepared by copolymerization of polyether, (meth) acrylate monomers and an initiator, the polyether modified polyacrylate copolymer has the following structure:

[0016]

[0017] wherein x, y, z are positive integers of 1-300, a, b are integers of 0-100; R1, R2 are H, alkyl of 1-33C, hydroxyalkyl or cycloalkyl, R3 is H, alkyl of 1-18C or alkanoyl of 1-18C.

[0018] As a further technical solution of the present application, a polyether modified polyacrylate defoamer, the polyether is a single-end allyl polyether, the (meth) acrylate includes acrylic acid and its alkyl ester, methacrylic acid and its alkyl ester, and the initiator is a thermal initiator.

[0019] As a further technical solution of the present application, a polyether modified polyacrylate defoamer, the molecular weight of the polyether and the acrylate copolymer is 10000-70000, the mass percentage content of the allyl polyether is 15-55%, and the mass percentage of the (meth) acrylate is 45-85%.

[0020] As a further technical solution of the present application, a polyether modified polyacrylate defoamer, the monomers of the polyether modified polyacrylate copolymer include the following components:

[0021]

[0022] As a further technical solution of the present application, a polyether modified polyacrylate defoamer, the molecular weight of the allyl polyether is 300-3000, and the EO / PO ratio is 4:6-0:10.

[0023] As a further technical solution of the present application, a polyether modified polyacrylate defoamer, the acrylate includes one or more of butyl acrylate, cyclohexyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, glycidyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, isobornyl acrylate, and glycidyl acrylate.

[0024] As a further technical solution of the present application, a polyether modified polyacrylate defoamer, the methacrylate includes one or more of butyl methacrylate, cyclohexyl methacrylate, isooctyl methacrylate, lauryl methacrylate, stearyl methacrylate, glycidyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, isobornyl methacrylate, and glycidyl methacrylate.

[0025] As a further technical solution of the present application, a polyether modified polyacrylate defoaming agent, the thermal initiator includes any one of azobisisobutyronitrile, azobisisoheptyl nitrile, dibenzoyl peroxide, tert-butyl peroxybenzoate, di-tert-amyl peroxide.

[0026] As a further technical solution of the present application, a polyether modified polyacrylate defoaming agent, the preparation method adopts a solvent-free method of dropping (meth) acrylate monomer and initiator mixed solvent to allyl polyether as the substrate, which has the characteristics of low VOC.

[0027] As a further technical solution of the present application, a polyether modified polyacrylate defoaming agent, the preparation method comprises the following steps:

[0028] Step 1: weigh the allyl polyether, add it to the device with stirring and condensation reflux, weigh the acrylate, methacrylate and 80-90% by weight of the initiator, mix and dissolve uniformly and put into the dropping device for standby;

[0029] Step 2: start stirring and heating the reaction device, the temperature rises to 80-120℃, start dropping the monomer and initiator solution, the dropping time is 3-4.5h, then the temperature is raised to 100-140℃ and kept for 1-3h;

[0030] Step 3: dissolve the remaining 10-20% by weight of the initiator in a small amount of low boiling point solvent and add it to the dropping device for standby, after the temperature holding is completed, start dropping the remaining initiator solution, drop for 0.5-1h, after the dropping is completed, continue to step 4: after the temperature holding is completed, distill under reduced pressure at 100-120℃

[0031] Remove the residual monomer to obtain the polyether modified polyacrylate defoaming agent.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] Using allyl polyether as the reaction substrate, the product is synthesized by dropping other acrylate and initiator mixed solution, which is safe and environmentally friendly, and has no VOC. The present application has excellent defoaming efficiency and compatibility, and is particularly suitable for defoaming and defoaming of solvent-based coatings such as alkyd resin, polyurethane resin and polyester resin, and has good popularization value, which can effectively solve the problems in the technical background.

Specific embodiments

[0034] Example 1

[0035] Formula:

[0036]

[0037] The above allyl polyether was added to a reactor. (Meth)acrylate monomer and 80% of the initiator were weighed and mixed thoroughly. The reactor was heated to 80°C, and the mixed monomer solution was added dropwise over 4 hours. The temperature was controlled at 80–85°C during the dropwise reaction. After the dropwise addition was complete, the temperature was raised to 100°C and held for 2 hours. After the holding time was complete, the remaining 20% ​​of the initiator was dissolved in a small amount of low-boiling-point solvent and slowly added dropwise to the reactor over 30 minutes. After the dropwise addition was complete, the temperature was maintained for another 1 hour, and the reaction was terminated. The residual monomer and solvent were distilled off under reduced pressure at 100–120°C with a vacuum degree of -0.09–0.1 MPa. The product was then cooled to below 60°C and discharged to obtain the polyether-modified polyacrylate defoamer. This was designated as Sample 1.

[0038] Example 2

[0039] formula:

[0040]

[0041]

[0042] The above allyl polyether was added to a reactor. (Meth)acrylate monomer and 80% of the initiator were weighed and mixed thoroughly. The reactor was heated to 90°C, and the mixed monomer solution was added dropwise over 4 hours. The temperature was controlled between 90 and 100°C during the dropwise reaction. After the dropwise addition was complete, the temperature was raised to 105°C and held for 2 hours. After the holding period, the mixture was dissolved in a small amount of low-boiling-point solvent.

[0043] The remaining 20% ​​of the initiator was slowly added dropwise to the reactor over 30 minutes. After the addition was complete, the mixture was kept at the same temperature for 1 hour to complete the reaction. The residual monomer and solvent were then distilled off under reduced pressure at 110–120°C and a vacuum of -0.09–0.1 MPa. The mixture was then cooled to below 60°C and discharged to obtain the polyether-modified polyacrylate defoamer. This was designated as Sample 2.

[0044] Example 3

[0045] formula:

[0046]

[0047] The above allyl polyether is put into a reaction kettle, (meth) acrylate monomer and 80% initiator are weighed and mixed uniformly, the reaction kettle is heated to 100°C, and the mixed monomer solution is started to be added dropwise, the dropwise adding time is 4h, the temperature is controlled at 100-105°C during the dropwise adding reaction, after the dropwise adding is completed, it is heated to 110°C and kept for 2h. After the keeping is completed, the remaining 20% initiator is dissolved in a small amount of low boiling point solvent, slowly added to the reaction kettle, and dropped within 30min, after the dropwise adding is completed, it is kept for 1h, the reaction is ended; the residual monomer and solvent are distilled out under reduced pressure at 110-120°C under vacuum degree of -(0.09-0.1) MPa, cooled to below 60°C, and discharged, thus the polyether modified polyacrylate defoaming agent is obtained. It is recorded as sample 3.

[0048] Example 4

[0049] Formula:

[0050]

[0051] The above allyl polyether is put into a reaction kettle, (meth) acrylate monomer and 80% initiator are weighed and mixed uniformly, the reaction kettle is heated to 100°C, and the mixed monomer solution is started to be added dropwise, the dropwise adding time is 4h, the temperature is controlled at 100-105°C during the dropwise adding reaction, after the dropwise adding is completed, it is heated to 110°C and kept for 2h. After the keeping is completed, the remaining 20% initiator is dissolved in a small amount of low boiling point solvent, slowly added to the reaction kettle, and dropped within 30min, after the dropwise adding is completed, it is kept for 1h, the reaction is ended; the residual monomer and solvent are distilled out under reduced pressure at 110-120°C under vacuum degree of -(0.09-0.1) MPa, cooled to below 60°C, and discharged, thus the polyether modified polyacrylate defoaming agent is obtained. It is recorded as sample 3.

[0052] Example 5

[0053] Formula:

[0054]

[0055] The above allyl polyether is put into a reaction kettle, (meth) acrylate monomer and 80% initiator are weighed and mixed uniformly, the reaction kettle is heated to 100°C, and the mixed monomer solution is started to be added dropwise, the dropwise adding time is 4h, the temperature is controlled at 100-105°C during the dropwise adding reaction, after the dropwise adding is completed, it is heated to 110°C and kept for 2h. After the keeping is completed, the remaining 20% initiator is dissolved in a small amount of low boiling point solvent, slowly added to the reaction kettle, and dropped within 30min, after the dropwise adding is completed, it is kept for 1h, the reaction is ended; the residual monomer and solvent are distilled out under reduced pressure at 110-120°C under vacuum degree of -(0.09-0.1) MPa, cooled to below 60°C, and discharged, thus the polyether modified polyacrylate defoaming agent is obtained. It is recorded as sample 3.

[0056] In a reaction kettle, (meth)acrylate monomers and 80% initiator were weighed and mixed uniformly, the reaction kettle was heated to 120°C to start dropping the mixed monomer solution, the dropping time was 4h, the temperature was controlled at 120-125°C during the dropping reaction, after the dropping was completed, the temperature was increased to 130°C and kept for 2h. After the keeping was completed, the remaining 20% initiator was dissolved in a small amount of low boiling point solvent and slowly dropped into the reaction kettle, the dropping was completed within 30min, after the dropping was completed, the keeping was continued for 1h, the reaction was completed; the residual monomers and solvent were distilled out under reduced pressure at 120-140°C and vacuum degree of - (0.09-0.1) MPa, the temperature was decreased to below 60°C to discharge the material, thus the polyether modified polyacrylate defoaming agent was obtained. It was recorded as sample 5.

[0057] Example 6

[0058] Formulation:

[0059]

[0060] The above allyl polyether was put into a reaction kettle, (meth)acrylate monomers and 80% initiator were weighed and mixed uniformly, the reaction kettle was heated to 122°C to start dropping the mixed monomer solution, the dropping time was 4h, the temperature was controlled at 122-130°C during the dropping reaction, after the dropping was completed, the temperature was increased to 130°C and kept for 2h. After the keeping was completed, the remaining 20% initiator was dissolved in a small amount of low boiling point solvent and slowly dropped into the reaction kettle, the dropping was completed within 30min, after the dropping was completed, the keeping was continued for 1h, the reaction was completed; the residual monomers and solvent were distilled out under reduced pressure at 130°C and vacuum degree of - (0.09-0.1) MPa, the temperature was decreased to below 60°C to discharge the material, thus the polyether modified polyacrylate defoaming agent was obtained. It was recorded as sample 6.

[0061] The defoaming effect tests of examples 1-6 were carried out according to the following test method:

[0062] Bulk density test

[0063] A certain amount of alkyd resin was weighed, 0.3% (active substance, based on the weight of the resin) of the defoaming agent diluted with xylene was added, and then it was dispersed at 800RPM for 5min, and then it was increased to 2000RPM for 30min, 100g of the sample was weighed and measured, and compared with the volume of 100g of the resin, the volume ratio was obtained, the larger the value, the worse the defoaming performance, and the values were divided into 1-5 grades from small to large.

[0064] Then 100g of the above dispersed sample was taken, stirred at 2000RPM for 5min after being placed for 15min, and then its volume was measured and compared with the initial volume; it was dispersed again after being placed for 15min, and the test was repeated for 3 times, and the average value of the volume ratio of the three times was taken as

[0065] The manifestation of the defoaming effect of the defoaming agent is divided into 1-5 levels from small to large values.

[0066] Pouring test

[0067] 100g of the alkyd resin is weighed, 0.3% (active substance, based on the weight of the resin) of the defoaming agent diluted with xylene is added, and first dispersed at 800 RPM for 5 min, and then increased to 2000 RPM for 30 min. After the dispersion is completed, 30g is immediately taken out and poured on a transparent glass plate placed obliquely, and the defoaming condition of the foam is observed. According to the defoaming speed, the smoothness of the plate surface, and the amount of residual foam, the defoaming agent is evaluated from good to bad, and divided into 1-5 levels. In addition, after the foam is completely defoamed, the compatibility of the defoaming agent with the resin is evaluated according to the influence on the transparency of the paint film, and the level 1 is completely or almost no influence, and the influence on the transparency is 5 levels in total, and the influence degree increases in turn.

[0068] Brushing plate test

[0069] A certain amount of curing agent and diluent is added to the alkyd resin, and 0.3% of the defoaming agent is added, and then dispersed at 2000 RPM for 30 min on a dispersing machine. Then, it is taken out and brushed on a 20*30cm beech plate with a brush, and the plate is brushed three times in a cross manner, and the smoothness of the plate surface and the conditions of the bright bubbles and dark bubbles are observed. The plate with almost no bright bubbles and dark bubbles, flat and no shrinkage is level 1, and then divided into 5 levels from good to bad.

[0070] The defoaming performance test results of examples 1-6 are as follows:

[0071]

[0072] The above results show that the defoaming agent of the present application has good performance in dynamic defoaming, static defoaming and actual application, and has good compatibility with the system, wider application, good popularization value and application prospect.

[0073] The numerical range of each process parameter involved in the present application cannot be fully embodied in the above examples, but those skilled in the art can fully imagine that any value falling within the above numerical range can implement the present application, and of course, any combination of specific values within several numerical ranges is also included. Here, specific examples within one or more numerical ranges are omitted, which should not be regarded as insufficient disclosure of the technical solution of the present application.

[0074] Each document mentioned above is incorporated by reference

[0075] incorporated herein by reference in their entirety for all purposes, including the priority to any prior application, whether or not specifically listed above. The reference to any document is not intended to constitute an admission that such document is prior art or constitutes the general knowledge of the skilled person in any jurisdiction. Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word "about."

Claims

1. A polyether-modified polyacrylate antifoam agent, characterized by, The polyether modified polyacrylate defoamer is copolymerized by polyether, acrylate and methacrylate monomers under the initiation of initiator, and the polyether modified polyacrylate copolymer has the following structure: wherein x, y, z are positive integers of 1-300, a, b are integers of 1-100; R1, R2 are H, alkyl of 1-33C, hydroxyalkyl or cycloalkyl, and R3 is H, alkyl of 1-18C or acyl of 1-18C.

2. The polyether-modified polyacrylate defoamer according to claim 1, characterized in that, The polyether is a single-end allyl polyether, the acrylate includes alkyl acrylate, and the methacrylate includes alkyl methacrylate.

3. The polyether-modified polyacrylate defoamer according to claim 1, characterized in that, The molecular weight of the polyether and acrylate copolymer is 10000-70000, the mass percentage content of the polyether is 15-55%, and the mass percentage of the acrylate and the methacrylate together is 45-85%.

4. The polyether-modified polyacrylate defoamer according to claim 3, characterized in that, The polyether modified polyacrylate copolymer comprises the following components: 1-30 parts of allyl polyether, 1-80 parts of acrylate, 1-80 parts of methacrylate and 0.1-2 parts of initiator.

5. The polyether-modified polyacrylate defoamer according to claim 2, characterized in that, The molecular weight of the allyl polyether is 300-3000, and the EO / PO ratio is 4:6-1:

10.

6. The polyether-modified polyacrylate defoamer according to claim 2, characterized in that, The acrylate includes one or more of butyl acrylate, cyclohexyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and isobornyl acrylate.

7. The polyether-modified polyacrylate defoamer according to claim 2, characterized in that, The methacrylate includes one or more of butyl methacrylate, cyclohexyl methacrylate, isooctyl methacrylate, lauryl methacrylate, stearyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and isobornyl methacrylate.

8. The polyether-modified polyacrylate defoamer according to claim 2, characterized in that, The thermal initiator includes any one of azobisisobutyronitrile, azobisisoheptyl nitrile, dibenzoyl peroxide, tert-butyl peroxybenzoate and di-tert-amyl peroxide.

9. A process for the preparation of the polyether-modified polyacrylate defoamer according to claim 1, characterized in that, The preparation method adopts a solvent-free method of dropping acrylate and methacrylate monomers and initiator mixture into allyl polyether as a substrate, and has the characteristics of low VOC.

10. The method for preparing the polyether-modified polyacrylate defoamer according to claim 9, characterized in that, The preparation method comprises the following steps: Step 1: weigh the allyl polyether, add it into a device with stirring and condensation reflux, weigh the acrylate, methacrylate and 80-90% by weight of the initiator, mix and dissolve them uniformly, and put them into a dropping device for standby; Step 2: start stirring and heating in the reaction device, the temperature rises to 80-120℃, then start dropping the monomer and initiator solution, the dropping time is 3-4.5h, then the temperature rises to 100-140℃ and is kept for 1-3h; Step 3: dissolve the remaining 10-20% by weight of the initiator in a small amount of low-boiling-point solvent and add it into the dropping device for standby, then start dropping the remaining initiator solution after the keeping, and the dropping is completed in 0.5-1h, then continue keeping for 1-3h; Step 4: after the keeping is completed, distill the residual monomers at 100-120℃ under reduced pressure to obtain the polyether modified polyacrylate defoamer.

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