Cationic acrylate emulsion and preparation method thereof
The preparation of cationic acrylate emulsions using glow discharge electrolytic plasma technology solves the stability and cost issues, achieving the preparation of highly stable and environmentally friendly cationic acrylate emulsions while simplifying the reaction apparatus.
Patent Information
- Application Number
- CN202511447389.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-11
- Publication Date
- 2026-01-20
AI Technical Summary
Existing technologies have poor stability of cationic acrylate emulsions, high synthesis costs, and traditional preparation methods suffer from high costs and environmental pollution problems.
The glow discharge electrolysis plasma technology is adopted, using hexadecyltrimethylammonium bromide and lauryl glucoside as composite emulsifiers. Highly active components are generated in aqueous solution through glow discharge electrolysis to initiate the emulsion polymerization of acrylate, avoiding the use of chemical initiators and polyvinyl alcohol protective colloids.
A cationic acrylate emulsion with high stability and uniform particle size distribution was prepared, which simplified the reaction device, reduced costs and environmental pollution.
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Figure CN121362281A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of coating emulsion preparation, in particular to a cationic acrylate emulsion and a preparation method thereof. BACKGROUND
[0002] Acrylate emulsion is widely used in leather, fabric, paper, adhesive, coating and other fields due to its excellent performance. Its common synthesis methods include chemical initiation, radiation initiation, light initiation, microwave initiation, etc. Chemical initiation needs to add sodium persulfate (Na2S2O8) as a polymerization initiator. However, due to the rapid reaction of the initiator, gel is easily produced, and soluble salt by-products such as Na2SO4 exist in the emulsion adhesive after the reaction. Although radiation initiation, light initiation, microwave initiation, etc. do not need an initiator, the cost of the radiation source device is high, and it is limited by the penetration and uniformity of the radiation. The molecular weight distribution of the polymerization product is generally wide, and the adhesion performance is not high.
[0003] In the synthesis of acrylate emulsion, anionic emulsifiers such as sodium dodecyl sulfate and sodium dodecyl sulfonate are usually used, so that the prepared emulsion is mainly anionic emulsion. However, some fields such as oil drilling, papermaking industry, coating, wastewater treatment, etc. need positively charged latex particles, because cationic acrylate emulsion has the advantages of weather resistance, good film forming property, corrosion resistance, sterilization, antistatic property, etc. In recent years, the preparation of cationic emulsion using cationic emulsifiers and cationic initiators has attracted people's attention. However, the stability of cationic acrylate emulsion is poor, and the requirements for emulsifiers and initiators are high. In order to obtain cationic acrylate emulsion with high stability, azo initiators or cationic monomers are usually used, and polyvinyl alcohol is used as a protective colloid to improve the stability of the emulsion. This increases the cost of emulsion synthesis, thereby hindering the development of cationic acrylate emulsion.
[0004] Glow discharge electrolysis is a new type of electrochemical method for generating low-temperature plasma in aqueous solution. By inserting the anode and cathode into the electrolyte solution at the same time, when a certain voltage is applied, plasma is generated at the tip of the anode, and hydrogen radicals (H·), hydroxyl radicals (OH·), oxygen radicals (O·), hydrated electrons (e aq - ), hydrogen peroxide (H2O2) and other high-activity components are generated at the plasma-liquid interface. Among them, OH· and H· have high activity and can initiate free radical initiation chain addition reaction of double bond (C=C) monomers. Compared with traditional cationic emulsion polymerization, glow discharge electrolysis does not need to add polyvinyl alcohol protective colloid or initiator. The prepared cationic acrylate emulsion has high stability, uniform particle size distribution, simple reaction device, no secondary pollution and is green and environmentally friendly. SUMMARY
[0005] The present application aims at the problems in the prior art, and provides a method for preparing cationic acrylate emulsion by using glow discharge electrolytic plasma technology.
[0006] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme.
[0007] The cationic acrylate emulsion is characterized by being composed of the following raw materials in parts by weight: 15-45 parts of hard monomer ethyl methacrylate (EMA), 2 parts of soft monomer butyl methacrylate (BMA), 10-30 parts of soft monomer butyl acrylate (BA), 1 part of functional monomer methacrylic acid (MMA), 2-10 parts of composite emulsifier, and 40-80 parts of deionized water.
[0008] The method for preparing the cationic acrylate emulsion is characterized by comprising the following steps.
[0009] Step one: the composite emulsifier is weighed in a 250 mL three-necked flask, deionized water is added, and heating and stirring are performed to obtain an emulsifier aqueous solution;
[0010] Step two: the hard monomer ethyl methacrylate, the soft monomer butyl methacrylate, the soft monomer butyl acrylate, and the functional monomer methacrylic acid are weighed and added into the three-necked flask of step one, the three-necked flask is placed in an oil bath at a certain temperature, heating and stirring are performed for a period of time, and a pre-emulsion is obtained;
[0011] Step three: the anode platinum needle and the cathode graphite carbon rod are inserted into the three-necked flask, a direct current power source is used to discharge and stir at a certain voltage, and emulsion polymerization is initiated;
[0012] Step four: after the discharge is stopped, the three-necked flask is moved into an oil bath at a certain temperature to perform a post-polymerization reaction, the three-necked flask is taken out after a period of time, is cooled to room temperature, a 200-mesh screen is used to filter and remove the gel, and a milky white polymeric product with blue light is obtained.
[0013] Preferably, in step one, the composite emulsifier is composed of cetyltrimethylammonium bromide (CTAB) and lauryl glucoside (APG-1200) at a ratio of (1-3):(1-3).
[0014] Preferably, the composite emulsifier accounts for 1%-7% of the total amount of monomers.
[0015] Preferably, in step two, the mass ratio of the soft monomer butyl methacrylate, the soft monomer butyl acrylate, the hard monomer ethyl methacrylate, and the functional monomer methacrylic acid is 1:(10-30):(15-45):1.
[0016] Preferably, in step two, the mass ratio of total monomer to deionized water is (22.5-45):(40-80).
[0017] Preferably, in step two, the emulsification temperature is 55-60℃, and the emulsification time is 0.5-1.0h.
[0018] Preferably, in step three, the discharge voltage is 500-600V, and the discharge time is 10-30min.
[0019] Preferably, in step four, the post-polymerization oil bath temperature is 80-100℃, the stirring speed is 80-100r / min, and the polymerization time is 3-5h.
[0020] The beneficial effects of the present application are:
[0021] 1. The present application uses ethyl methacrylate (EMA), butyl methacrylate (BMA), butyl acrylate (BA), and methyl methacrylate (MMA) as hard-soft monomers and functional monomers, cetyltrimethylammonium bromide (CTAB) and lauryl glucoside (APG-1200) as composite emulsifiers, and a one-step cationic acrylate emulsion is prepared by glow discharge electrolytic plasma initiation. The method is simple in device and easy to operate, the synthesis process is controllable, and it is green and environmentally friendly.
[0022] 2. The preparation process of the present application does not require N2, and no by-products (such as Na2SO4) are generated, and the conditions are mild.
[0023] 3. The present application does not need to add a chemical initiator, and does not need to use polyvinyl alcohol to protect the colloid, and the prepared cationic emulsion has high stability and does not produce side reactions.
[0024] 4. The present application uses cetyltrimethylammonium bromide (CTAB) and lauryl glucoside (APG-1200) as composite emulsifiers, making the prepared emulsion more green and environmentally friendly.
[0025] 5. The cationic acrylate emulsion prepared by the present application has high stability, good film-forming property, and strong adhesion. BRIEF DESCRIPTION OF DRAWINGS
[0026] Figure 1 Experimental device for preparing emulsion
[0027] Figure 2 Current-voltage curve (a) of glow discharge electrolysis in Example 1 of the present application and glow photo at 580V (b)
[0028] Figure 3 Infrared spectra of monomers and cationic acrylate emulsion glue film in Example 1 of the present application;
[0029] Figure 4TEM and particle size distribution of the cationic acrylate emulsion in Example 1 (a, a'), Example 2 (b, b') and Example 3 (c, c') of the present application, respectively;
[0030] Figure 5 Zeta potential (a) and particle size test (b) of the cationic acrylate emulsion in Example 1 of the present application;
[0031] Figure 6 Thermogravimetric curve of the cationic acrylate emulsion film in Example 1 of the present application.
[0032] Figure 7 Differential scanning calorimetric graph of the cationic acrylate emulsion film in Example 1 of the present application.
[0033] Figure 8 Contact angle test graph of the cationic acrylate emulsion film in Example 1 of the present application. DETAILED DESCRIPTION
[0034] The technical solutions of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0035] Example 1
[0036] Take 2.25g of composite emulsifier (CTAB, APG-1200 added in a ratio of 2:1) and 80g of deionized water into a 250mL three-necked flask, stir and dissolve to obtain an emulsifier solution. According to the formula, add the monomers respectively: 16g of ethyl methacrylate, 2g of butyl methacrylate, 26g of butyl acrylate, and 1g of methacrylic acid. Put the three-necked flask into a 55℃ oil bath for heating and stirring for pre-emulsification for 45min. After pre-emulsification, take 80mL of the pre-emulsion and carry out glow discharge for 15min under a voltage of 560V. After the discharge is completed, continue to stir and polymerize at an oil bath temperature of 90℃ for 3h, take out, cool to room temperature, filter to remove the gel with a 200 mesh screen, and finally obtain a cationic acrylate emulsion with milky white and blue light. The infrared spectrum is shown in Figure 3 , the TEM is shown in Figure 4 a, the Zeta potential and particle size test is shown in Figure 5 , the thermogravimetric analysis is shown in Figure 6 , the differential thermal analysis is shown in Figure 7 , and the contact angle analysis is shown in Figure 8 .
[0037] Example 2
[0038] Take 2.88 g of composite emulsifier (CTAB, APG-1200 is added according to the ratio of 3:1) and 83 g of deionized water into a 250 mL three-necked flask, stir and dissolve to obtain an emulsifier solution. According to the formula, add monomers respectively: 18 g of ethyl methacrylate, 2 g of butyl methacrylate, 27 g of butyl acrylate, 1 g of methacrylic acid. Put the three-necked flask into a 50℃ oil bath for heating and stirring for pre-emulsification for 30 min. After pre-emulsification, take 80 mL of pre-emulsion for glow discharge for 20 min under 580 V voltage. After the discharge is completed, continue to stir and react for 4 h in a 95℃ oil bath, then take out, cool to room temperature, filter to remove the gel with a 200 mesh screen, and finally obtain a cationic acrylate emulsion with milky white and blue light. The glow photo under 580 V voltage is shown in Figure 2 b, TEM is shown in Figure 4 b.
[0039] Example 3
[0040] Take 2.7 g of composite emulsifier (CTAB, APG-1200 is added according to the ratio of 1:1) and 80 g of deionized water into a 250 mL three-necked flask, stir and dissolve to obtain an emulsifier solution. According to the formula, add monomers respectively: 14 g of ethyl methacrylate, 2 g of butyl methacrylate, 28 g of butyl acrylate, 1 g of methacrylic acid. Put the three-necked flask into a 60℃ oil bath for heating and stirring for pre-emulsification for 25 min. After pre-emulsification, take 80 mL of pre-emulsion for glow discharge for 25 min under 520 V voltage. After the discharge is completed, continue to stir and react for 3 h in a 95℃ oil bath, then take out, cool to room temperature, filter to remove the gel with a 200 mesh screen, and finally obtain a cationic acrylate emulsion with milky white and blue light, TEM is shown in Figure 4 c.
[0041] Example 4
[0042] The structure of the cationic acrylate emulsion prepared by the present application is analyzed and explained by current-voltage curve, infrared spectrum, transmission electron microscope, and thermogravimetric analysis, etc.
[0043] Experimental device: the experimental device is shown in Figure 1 , which is composed of a direct current stabilized voltage and current source (provided by Shanghai Liyou Company) and a reaction container, and the reaction container is combined by an anode platinum wire (diameter of 0.3-0.8 mm), a cathode graphite rod (diameter of 3-7 mm) and a reflux condenser. The cathode and anode are immersed into the liquid surface by 0.5-1.5 cm, and the distance between the electrodes is 1-2 cm. A magnetic stirrer is installed in the three-necked flask, and the reaction container is placed in a constant temperature oil bath.
[0044] 1. Current-voltage curve
[0045] Figure 2a is the current-voltage curve of preparing cationic acrylate emulsion. It can be seen that the current-voltage curve is divided into four stages. In AB section, the current increases with the increase of voltage, which accords with Faraday's law of electrolysis, and belongs to ordinary electrolysis area. In BC section, with the increase of voltage, the current fluctuates suddenly and decreases, and a large number of bubbles can be seen around the anode platinum needle. This is because the steam sheath layer is formed around the anode platinum needle, which makes the anode and the electrolyte solution insulate, causing the current fluctuation; because the conductivity of the electrolyte is much higher than that of the gas film, the equivalent resistance of the gas-liquid interface increases, and the current decreases. At point C, a weak flash can be observed on the anode, which is the critical voltage of glow discharge, and weak glow begins to occur. In CD section, with the increase of voltage, the current is almost constant, but the glow becomes brighter. At this time, a large number of H·, OH·, e aq - , H2O2 and other high active substances are produced at the plasma-liquid interface. In DE section, with the increase of voltage, the current increases rapidly, and the anode glow is abnormally strong at this time, producing Joule heat, which rapidly raises the temperature, leading to the high-temperature melting of the platinum needle, and this area is called abnormal glow discharge area. Therefore, the voltage of 500-600 V is adopted for preparing cationic acrylate emulsion. The glow photo produced at 580 V is shown in Figure 2 b, which confirms that the method for preparing the emulsion is the glow discharge electrolytic plasma technology.
[0046] 2. Infrared test
[0047] The structure of the sample was characterized by iS50 ATR-FTIR spectrometer of Thermo Fisher Corporation of the United States. Figure 3 The infrared spectrum of the hard monomer ethyl methacrylate, the soft monomer butyl acrylate and the cationic acrylate emulsion film. The peaks between 3029-2737 cm -1 are the C-H stretching vibration peaks, and the peak at 1727 cm -1 is the characteristic peak of -C=O. The characteristic peaks of anti-symmetric and symmetric stretching vibration of C-O-C are at 1150 and 1240 cm -1 . After the synthesis of the emulsion, no characteristic peak of C=C is found near 1630 cm -1 , indicating that the monomers all participate in the reaction and the polymerization is complete.
[0048] 3. Transmission electron microscopy test
[0049] The emulsion was diluted to 5% by mass fraction, 10 μL of the sample was taken and dropped on the copper mesh for precipitation for 1 min, and the floating liquid was absorbed by filter paper. Then 10 μL of phosphotungstic acid staining solution was added, and the image was collected after drying for several minutes. Figure 4 The transmission electron microscopy (TEM) of the cationic acrylate emulsion is shown in Figure 4a and a' are transmission electron microscopy (TEM) and particle size analysis images of the cationic acrylate emulsion in Example 1. It can be seen that the latex particles are small spheres, uniformly distributed, and have a particle size of approximately 90.2 nm. Figure 4 b and b' are transmission electron microscopy (TEM) and particle size analysis images of the cationic acrylate emulsion in Example 2. It can be seen that the latex particles are small spherical, uniformly distributed, and have a particle size of approximately 94.5 nm. 4c and c' are TEM and particle size analysis images of the cationic acrylate emulsion in Example 3. It can be seen that the latex particles are small spherical, uniformly distributed, and have a particle size of approximately 83.2 nm. In summary, the latex particles prepared by glow discharge electrolysis are spherical with an average particle size of 80–100 nm.
[0050] 4. Emulsion Zeta potential and particle size
[0051] The zeta potential and particle size of the emulsion were determined using a Zetasizer Nano AS90 from Malvern, UK. Figure 5 This is a diagram showing the Zeta potential and particle size distribution of a cationic acrylate emulsion. Figure 5 As can be seen from a, the Zeta potential of the emulsion is +79.1 mV, and its absolute value is greater than 30 mV, indicating that the emulsion has good stability. The Zeta potential indicates that the latex particles carry a positive charge, indicating that it is a cationic emulsion. This is because the cationic surfactant CTAB was used in the emulsion synthesis process, which makes the surface of the latex particles carry a positive charge. Figure 5 b indicates that the emulsion particle size distribution is between 50 and 150 nm, exhibiting a unimodal distribution, with an average particle size of 95.2 nm. This is consistent with the particle size estimated by TEM.
[0052] 5. Thermogravimetric analysis (TG)
[0053] The thermal stability of cationic acrylate emulsion films was determined using a Shimadzu DTG-60A thermogravimetric analyzer. Figure 6 The thermogravimetric curves of the film show that the initial degradation temperature of the cationic acrylate film is 25–310℃, mainly due to the loss of adsorbed water and low molecular weight substances, leading to mass loss. The latex film begins to decompose at 351℃, primarily due to the breakage of large molecules, resulting in weight loss. The maximum thermal decomposition temperature of the film is 430℃. These data indicate that the cationic acrylate emulsion exhibits good thermal stability.
[0054] 6. Differential Scanning Calorimetry (DSC)
[0055] The glass transition temperature of the film was measured using a Netzsch 214 Polyma differential scanning calorimeter (Germany). Figure 7 It can be seen that this latex film has only one glass transition temperature (T). g= -0.331 °C), indicating that the cationic acrylate emulsion polymerization was complete.
[0056] 7. Contact angle test
[0057] The wetting property of the latex film was tested at room temperature by using a DSA100E contact angle meter from KRUSS, Germany. When the static water contact angle of the latex film surface is less than 90°, it is a hydrophilic material, greater than 90° and less than 150°, it is a hydrophobic material, and greater than 150°, it is a super-hydrophobic material. As shown in Table 1, the contact angle of the cationic acrylate emulsion is about 60.026°, indicating that the latex film is a hydrophilic material. Figure 8
[0058] Example 5
[0059] (1) Mechanical stability test. 1%, 2%, and 3% of the emulsion in Examples 1-3 were respectively taken and centrifuged at a speed of 6000 r·min -1 for 30 min. Whether the emulsion had precipitation and stratification was observed. The experimental results are shown in Table 1.
[0060] (2) Dilution stability. 1%, 2%, and 3% of the emulsion in Examples 1-3 were respectively taken and left still at room temperature for 48 h. Whether the emulsion had precipitation and stratification was observed. The experimental results are shown in Table 1.
[0061] (3) Ca 2+ ion stability. 4 mL of 1%, 2%, and 3% of the emulsion in Examples 1-3 was respectively taken and added to a solution containing 1 mL of 0.5% CaCl2. After being left still at room temperature for 48 h, whether the emulsion had precipitation and stratification was observed. The experimental results are shown in Table 1.
[0062] (4) Thermal stability test. 1%, 2%, and 3% of the emulsion in Examples 1-3 was respectively taken and placed in a glass bottle with good sealing. After being placed in an oven at 60 °C for 48 h, it was taken out and cooled to room temperature. Whether the emulsion had precipitation and stratification was observed. The experimental results are shown in Table 1.
[0063] (5) Freeze-thaw stability test. 1%, 2%, and 3% of the emulsion in Examples 1-3 was respectively taken and placed in a glass bottle with good sealing. After being placed in a refrigerator at -18 °C for 48 h, it was taken out and placed at 30 °C for 48 h. Whether the emulsion had precipitation and stratification was observed. The experimental results are shown in Table 1.
[0064] It can be seen that all the above tests have no stratification and precipitation, indicating that the emulsion has good mechanical stability, dilution stability, Ca 2+ Ion stability, thermal stability and freeze-thaw stability.
[0065] Table 1 Experimental results
[0066] Example Mechanical stability Dilution stability Ca + stability Thermal stability Freeze-thaw stability Example 1 Not delaminated Not delaminated Not delaminated Not delaminated Not delaminated Example 2 Not delaminated Not delaminated Not delaminated Not delaminated Not delaminated Example 3 Not delaminated Not delaminated Not delaminated Not delaminated Not delaminated
[0067] It will be apparent to those skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects as illustrative only and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference herein to any prior art is to be taken as an admission that the application is not entitled to antedate such prior art by virtue of prior application. No reference to an item of prior art in any claim is to be construed as an admission that the item is widely available in the patent and non-patent literature as prior art. Any reference to a document herein is not to be taken as an admission that the document is part of the common general knowledge of the public. No disclaimer of any priority benefit is intended. No disclaimer of any admission is intended. No admission that any reference constitutes prior art is intended. No admission that any portion of a document is prior art is intended. No portion of a document can be construed as a disclaimer of any claim.
Claims
1. A cationic acrylate emulsion, characterized in that, The emulsion is prepared from the following raw materials in parts by weight: 15-45 parts of hard monomer ethyl methacrylate, 2 parts of soft monomer butyl methacrylate, 10-30 parts of soft monomer butyl acrylate, 1 part of functional monomer methacrylic acid, 2-10 parts of composite emulsifier, and 40-80 parts of deionized water.
2. A process for the preparation of a cationic acrylate emulsion, characterized in that, The method comprises the following steps: In step one, the composite emulsifier is weighed into a 250 mL three-necked flask, and deionized water is added, and heated and stirred to obtain an emulsifier solution; In step two, the hard monomer ethyl methacrylate, the soft monomer butyl methacrylate, the soft monomer butyl acrylate, and the functional monomer methacrylic acid are weighed and added into the three-necked flask in step one, and the three-necked flask is placed in an oil bath at a certain temperature, and heated and stirred for a period of time to obtain a pre-emulsion; In step three, an anode platinum needle and a cathode graphite carbon rod are inserted into the three-necked flask, and a direct current power source is used to discharge at a certain voltage for a period of time while stirring to initiate emulsion polymerization; In step four, after the discharge is stopped, the three-necked flask is moved into an oil bath at a certain temperature for polymerization reaction, and after a period of time, the three-necked flask is taken out, cooled to room temperature, filtered through a 200-mesh screen to remove gel, and a milky white blue light-emitting polymerization product is obtained.
3. The method for preparing a cationic acrylate emulsion according to claim 2, characterized in that: In step one, the composite emulsifier is composed of cetyltrimethylammonium bromide and lauryl glucoside.
4. The method for preparing a cationic acrylate emulsion according to claim 3, characterized in that: In step one, the ratio of cetyltrimethylammonium bromide to lauryl glucoside is (1-3):(1-3).
5. The method for preparing a cationic acrylate emulsion according to claim 2, characterized in that: The amount of the composite emulsifier accounts for 1-7% of the total mass of the monomers.
6. The method for preparing a cationic acrylate emulsion according to claim 2, characterized in that: In step two, the mass ratio of the soft monomer butyl methacrylate, the soft monomer butyl acrylate, the hard monomer ethyl methacrylate, and the functional monomer methacrylic acid is 1:(10-30):(15-45):
1.
7. The method for preparing a cationic acrylate emulsion according to claim 2, characterized in that: In step two, the mass ratio of the total mass of the monomers to deionized water is (22.5-45):(40-80).
8. The method for preparing a cationic acrylate emulsion according to claim 2, characterized in that: In step two, the emulsification temperature is 55-60°C, and the emulsification time is 0.5-1.0 h.
9. The method for preparing a cationic acrylate emulsion according to claim 2, characterized in that: In step three, the discharge voltage is 500-600 V, and the discharge time is 10-30 min.
10. The method for preparing a cationic acrylate emulsion according to claim 2, characterized in that: In step four, the polymerization oil bath temperature is 80-100°C, the stirring speed is 80-100 r / min, and the polymerization time is 3-5 h.