A process for the preparation of a peelable emulsion

Abstract

This disclosure relates to the field of polymer emulsions, specifically to a method for preparing a peelable emulsion. The method includes: reacting glycidyl methacrylate, amino-terminated silicone oil, and sodium flakes at room temperature with stirring in the dark, and filtering to obtain double-bond modified silicone oil; separating a vinyl monomer into a first monomer and a second monomer, and dispersing the double-bond modified silicone oil in the first monomer to obtain a third monomer; preparing a pre-emulsion by ultrasonic emulsification of the second monomer, an emulsifier, and water; adding the pre-emulsion, an aqueous solution of the crosslinking monomer, and an aqueous solution of the first ammonium persulfate to a reaction vessel to form a core-phase emulsion; adding the third monomer and the aqueous solution of the second ammonium persulfate dropwise into the core-phase emulsion to form a core-shell emulsion; naturally cooling the core-shell emulsion, adjusting the pH to 7-8 with ammonia, and filtering to obtain a peelable emulsion. The method for preparing a peelable emulsion provided in this disclosure aims to overcome problems such as weakened peelable coating performance caused by excessive use of release agents.

Description

Technical Field

[0001] This disclosure relates to the field of polymer emulsions, and more specifically to a method for preparing a peelable emulsion. Background Technology

[0002] my country's export of wind turbine towers and blades has achieved economies of scale. However, these towers and blades are susceptible to damage from impacts, scratches, and rain during sea transport. To prevent damage to their surfaces, a feasible method is to spray a peelable coating for temporary protection, which is then removed upon delivery. Currently, peelable coatings are widely used for temporary protection in ship painting, offshore oil platforms, glass / metal curtain walls, component machining, and welding. Peelable coatings prevent mechanical damage such as trampling, impacts, and scratches, as well as rain erosion. They have moderate adhesion and can be easily peeled off after use, significantly reducing the costs associated with rework and surface repair.

[0003] Peelable coatings are water-based coatings composed of film-forming agents, release agents, fillers, and additives. Acrylic resin emulsions are commonly used as film-forming agents. Due to their good adhesion, low surface energy substances such as organosilicon, organofluorine compounds, or calcium carbonate powders are usually added as release agents to achieve good peeling results. The low adhesion between the release agent and the substrate reduces the overall adhesion of the coating. Because of insufficient compatibility between the release agent and the film-forming agent, it forms an island-like structure in the coating, resulting in a discontinuous distribution of strong and weak adhesion. Therefore, a large amount of release agent is usually required. However, excessive introduction of release agents often weakens the mechanical and water resistance properties of the coating.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this disclosure is to provide a method for preparing a peelable emulsion, which aims to overcome, to some extent, the problem of weakened peelable coating performance caused by excessive use of peeling agents.

[0006] Other features and advantages of this disclosure will become apparent from the following detailed description, or may be learned in part from practice of this disclosure.

[0007] According to one aspect of the present disclosure, a method for preparing a peelable emulsion is provided, comprising: reacting glycidyl methacrylate, amino-terminated silicone oil, and sodium flakes in a light-protected stirring reaction at room temperature, and filtering to obtain double-bond modified silicone oil; resolving a vinyl monomer into a first monomer and a second monomer, and dispersing the double-bond modified silicone oil in the first monomer to obtain a third monomer; preparing a pre-emulsion by ultrasonic emulsification of the second monomer, an emulsifier, and water, and adding the pre-emulsion, an aqueous solution of a crosslinking monomer, and an aqueous solution of a first ammonium persulfate to a reaction vessel to form a core-phase emulsion; adding the third monomer and the aqueous solution of the second ammonium persulfate dropwise into the core-phase emulsion to form a core-shell emulsion; naturally cooling the core-shell emulsion to lower its temperature, adjusting the pH to 7-8 with ammonia water, and filtering to obtain a peelable emulsion.

[0008] According to some embodiments of this disclosure, based on the foregoing scheme, the molar ratio of the glycidyl methacrylate and the amino-terminated silicone oil is (1-2):1.

[0009] According to some embodiments of this disclosure, based on the foregoing scheme, the amine value of the amino-terminated silicone oil is 0.15-0.3 mL·1NHCl / g.

[0010] According to some embodiments of this disclosure, based on the foregoing scheme, the vinyl monomer is a mixture of methyl methacrylate and butyl acrylate; the mass ratio of methyl methacrylate to butyl acrylate is 1:(0.8-1.5).

[0011] According to some embodiments of this disclosure, based on the foregoing scheme, the mass ratio of the double bond modified silicone oil to the vinyl monomer is (1-2):200.

[0012] According to some embodiments of this disclosure, based on the foregoing scheme, the emulsifier is a mixture of sodium dodecyl sulfate and OP-10; the mass ratio of sodium dodecyl sulfate to OP-10 is 2:1; and the amount of sodium dodecyl sulfate and OP-10 used is 1 to 4% of the mass of the vinyl monomer.

[0013] According to some embodiments of this disclosure, based on the foregoing scheme, the crosslinking monomer is N,N-methylenebisacrylamide, and the amount of N,N-methylenebisacrylamide used is 0.5-1.5% of the mass of the vinyl monomer; the crosslinking monomer aqueous solution is an N,N-methylenebisacrylamide aqueous solution, and the concentration of the N,N-methylenebisacrylamide aqueous solution is 3-7%.

[0014] According to some embodiments of this disclosure, based on the foregoing scheme, the mass ratio of ammonium persulfate in the first and second ammonium persulfate aqueous solutions is the same, and the mass of the ammonium persulfate is 2-3% of the mass of the vinyl monomer.

[0015] According to some embodiments of this disclosure, based on the foregoing scheme, the step of adding the pre-emulsion, crosslinking monomer aqueous solution, and ammonium persulfate aqueous solution to a reaction vessel to form a nucleus emulsion includes: adding the pre-emulsion to the reaction vessel and heating it to 75°C; simultaneously adding the crosslinking monomer aqueous solution and the ammonium persulfate aqueous solution to the pre-emulsion within 1 hour, and maintaining the temperature for 2 hours to form the nucleus emulsion.

[0016] According to some embodiments of this disclosure, based on the foregoing scheme, the step of adding the third monomer and the second ammonium persulfate aqueous solution dropwise into the core phase emulsion to form a core-shell emulsion includes: simultaneously adding the third monomer and the second ammonium persulfate aqueous solution dropwise into the core phase emulsion within 1 hour, and maintaining the temperature for 2 hours to form the core-shell emulsion.

[0017] The exemplary embodiments disclosed herein may have some or all of the following beneficial effects:

[0018] In some embodiments of this disclosure, the technical solutions provided include, on the one hand, the room-temperature ring-opening reaction of epoxy groups and amino groups to graft glycidyl methacrylate containing highly reactive double bonds onto terminal amino silanes, and the in-situ introduction of low surface energy double-bond modified silicone oil into the polyacrylate polymer chain, thereby reducing the overall polarity of the polyacrylate molecules at the microscopic molecular level, weakening its intrinsic adhesion, and thus effectively reducing the amount of release agent required, avoiding its impact on the overall performance of the coating, and giving it excellent peelability; on the other hand, the core-shell emulsion polymerization method is used to introduce the pre-crosslinked monomer N,N-methylenebisacrylamide into the core phase to crosslink the acrylate polymer chain, effectively improving its mechanical properties, while the introduction of double-bond modified silicone oil into the shell phase, utilizing its long molecular chains to physically entangle with the polyacrylate molecular chains, enhances the interaction between latex particles and the density of the emulsion film, which can also improve its mechanical properties.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0021] Figure 1 The illustration shows a schematic flowchart of a method for preparing a peelable emulsion according to an exemplary embodiment of the present disclosure.

[0022] Figure 2 A transmission electron microscope image of a core-shell structured peelable emulsion prepared according to exemplary embodiment 1 of this disclosure is shown.

[0023] To further illustrate the implementation scheme of this disclosure, the various embodiments of this disclosure are described below. Detailed Implementation

[0024] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art.

[0025] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0026] my country's export of wind turbine towers and blades has achieved economies of scale. However, these towers and blades are susceptible to damage from impacts, scratches, and rain during sea transport. To prevent damage to their surfaces, a feasible method is to spray a peelable coating for temporary protection, which is then removed upon delivery. Currently, peelable coatings are widely used for temporary protection in ship painting, offshore oil platforms, glass / metal curtain walls, component machining, and welding. Peelable coatings prevent mechanical damage such as trampling, impacts, and scratches, as well as rain erosion. They have moderate adhesion and can be easily peeled off after use, significantly reducing the costs associated with rework and surface repair.

[0027] Peelable coatings are water-based coatings composed of film-forming agents, release agents, fillers, and additives. Acrylic resin emulsions are commonly used as film-forming agents. Due to their good adhesion, low surface energy substances such as organosilicon, organofluorine compounds, or calcium carbonate powders are usually added as release agents to achieve good peeling results. The low adhesion between the release agent and the substrate reduces the overall adhesion of the coating. Because of insufficient compatibility between the release agent and the film-forming agent, it forms an island-like structure in the coating, resulting in a discontinuous distribution of strong and weak adhesion. Therefore, a large amount of release agent is usually required. However, excessive introduction of release agents often weakens the mechanical and water resistance properties of the coating.

[0028] Therefore, this disclosure provides a method for preparing a peelable emulsion, which aims to overcome, to some extent, the problem of weakened peelable coating performance caused by excessive use of peeling agents.

[0029] The implementation details of the technical solutions of the embodiments of this disclosure are described in detail below.

[0030] Figure 1 This schematically illustrates a process flow diagram of a method for preparing a peelable emulsion according to an exemplary embodiment of the present disclosure. Figure 1 As shown, the method for preparing the peelable emulsion includes steps S101 to S105:

[0031] Step S101: Glycidyl methacrylate, amino-terminated silicone oil and sodium flakes are stirred and reacted at room temperature in the dark, and filtered to obtain double bond modified silicone oil.

[0032] Step S102: The vinyl monomer is split into a first monomer and a second monomer, and the double bond modified silicone oil is dispersed in the first monomer to obtain a third monomer;

[0033] Step S103: The second monomer, emulsifier and water are ultrasonically emulsified to prepare a pre-emulsion, and the pre-emulsion, crosslinking monomer aqueous solution and first ammonium persulfate aqueous solution are added to the reaction vessel to form a nucleus emulsion;

[0034] Step S104: The third monomer and the second ammonium persulfate aqueous solution are added dropwise to the core phase emulsion to form a core-shell emulsion;

[0035] Step S105: The core-shell emulsion is naturally cooled down, the pH is adjusted to 7-8 with ammonia, and then filtered to obtain a peelable emulsion.

[0036] In some embodiments of this disclosure, the technical solutions provided include, on the one hand, the room-temperature ring-opening reaction of epoxy groups and amino groups to graft glycidyl methacrylate containing highly reactive double bonds onto terminal amino silanes, and the in-situ introduction of low surface energy double-bond modified silicone oil into the polyacrylate polymer chain, thereby reducing the overall polarity of the polyacrylate molecules at the microscopic molecular level, weakening its intrinsic adhesion, and thus effectively reducing the amount of release agent required, avoiding its impact on the overall performance of the coating, and giving it excellent peelability; on the other hand, the core-shell emulsion polymerization method is used to introduce the pre-crosslinked monomer N,N-methylenebisacrylamide into the core phase to crosslink the acrylate polymer chain, effectively improving its mechanical properties, while the introduction of double-bond modified silicone oil into the shell phase, utilizing its long molecular chains to physically entangle with the polyacrylate molecular chains, enhances the interaction between latex particles and the density of the emulsion film, which can also improve its mechanical properties.

[0037] In one embodiment of this disclosure, the molar ratio of glycidyl methacrylate to the amino-terminated silicone oil in step S101 is (1-2):1. The amine value of the amino-terminated silicone oil is 0.15-0.3 mL·1NHCl / g.

[0038] In one embodiment of this disclosure, the vinyl monomer in step S102 is a mixture of methyl methacrylate and butyl acrylate, wherein the mass ratio of methyl methacrylate to butyl acrylate is 1:(0.8-1.5).

[0039] In one embodiment of this disclosure, when the double bond modified silicone oil is dispersed in the first monomer in step S102, the mass ratio of the double bond modified silicone oil to the vinyl monomer is (1-2):200.

[0040] In one embodiment of this disclosure, the emulsifier in step S103 is a mixture of sodium dodecyl sulfate and OP-10, with a mass ratio of sodium dodecyl sulfate to OP-10 of 2:1, and the amount of sodium dodecyl sulfate and OP-10 used is 1 to 4% of the mass of the vinyl monomer.

[0041] In one embodiment of this disclosure, the crosslinking monomer in step S103 is N,N-methylenebisacrylamide, and the amount of N,N-methylenebisacrylamide used is 0.5-1.5% of the mass of the vinyl monomer. The crosslinking monomer aqueous solution is an aqueous solution of N,N-methylenebisacrylamide with a concentration of 3-7%.

[0042] In one embodiment of this disclosure, the specific process of adding the pre-emulsion, crosslinking monomer aqueous solution and first ammonium persulfate aqueous solution to the reaction vessel in step S104 to form a nucleus emulsion is as follows: first, the pre-emulsion is added to the reaction vessel and heated to 75°C, and then the crosslinking monomer aqueous solution and the first ammonium persulfate aqueous solution are simultaneously added dropwise to the pre-emulsion within 1 hour, and the reaction is kept at the temperature for 2 hours to form a nucleus emulsion.

[0043] In one embodiment of this disclosure, the specific process of adding the third monomer and the second ammonium persulfate aqueous solution to the core phase emulsion in step S105 to form a core-shell emulsion is as follows: the third monomer and the second ammonium persulfate aqueous solution are simultaneously added to the core phase emulsion within 1 hour, and the reaction is kept at a certain temperature for 2 hours to form a core-shell emulsion.

[0044] It should be noted that the mass ratio of ammonium persulfate in the first and second ammonium persulfate aqueous solutions is the same, and the mass of ammonium persulfate is 2-3% of the mass of the vinyl monomer. Therefore, in the preparation, the ammonium persulfate aqueous solution with the above mass ratio can be prepared first, and then it can be divided into the first and second ammonium persulfate aqueous solutions, and the ratio of the first and second ammonium persulfate aqueous solutions is 2:1.

[0045] Example 1

[0046] (1) Add 0.01 mol glycidyl methacrylate, 0.01 mol amino-terminated silicone oil with an amine value of 0.15 and 0.5 g clean sodium flakes to a single-necked flask, stir and react at room temperature in the dark for 12 h, and filter to obtain double bond modified silicone oil.

[0047] (2) Weigh 33.34g of methyl methacrylate and 26.66g of butyl acrylate and mix them. Divide the mixed monomers into two parts in a 1:1 ratio, and label them as the second monomer and the first monomer, respectively. Disperse 0.6g of double bond modified silicone oil in the first monomer to obtain the third monomer.

[0048] (3) Heat the 250mL reactor equipped with a stirrer and reflux device to 75℃, and prepare a pre-emulsion by ultrasonic emulsification of the second monomer, 1.2g sodium dodecyl sulfate, 0.6g OP-10 and 30g water. Within 1h, add 6g of 5% N,N-methylenebisacrylamide aqueous solution and 30g of 3.34% ammonium persulfate aqueous solution dropwise into the reactor and keep it at the temperature for 2h to form a nucleus emulsion.

[0049] (4) The remaining 15g of 3.34% ammonium persulfate aqueous solution and the third monomer were simultaneously added dropwise into the reactor within 1 hour. The reaction was kept at the temperature for 2 hours to form a core-shell emulsion. The mixture was then allowed to cool naturally, and the pH was adjusted to 7-8 with ammonia water. The mixture was then filtered and discharged.

[0050] (5) Take 60 parts of the product emulsion, add 3 parts of calcium carbonate peeling agent, 0.6 parts of silica filler, 10 parts of sepiolite filler, 0.3 parts of defoamer and 0.3 parts of thickener in sequence while stirring, and mix them to form a water-based peelable coating. Spray the coating on the tinplate sheet, and test the peel strength and tensile strength after the coating dries.

[0051] Example 2

[0052] (1) Add 0.01 mol glycidyl methacrylate, 0.01 mol amino-terminated silicone oil with an amine value of 0.2 and 0.5 g clean sodium flakes to a single-necked flask, stir and react at room temperature in the dark for 12 h, and filter to obtain double bond modified silicone oil.

[0053] (2) Weigh 50g of methyl methacrylate and 50g of butyl acrylate and mix them. Divide them into two parts in a 1:1 ratio and label them as the second monomer and the first monomer, respectively. Disperse 0.5g of double bond modified silicone oil in the first monomer to obtain the third monomer.

[0054] (3) Heat the 500mL reactor equipped with a stirrer and reflux device to 75℃, and prepare a pre-emulsion by ultrasonic emulsification of the second monomer, 0.67g sodium dodecyl sulfate, 0.33g OP-10 and 50g water. Within 1h, add 20g of 3% N,N-methylenebisacrylamide aqueous solution and 50g of 2.22% ammonium persulfate aqueous solution dropwise into the reactor and keep it at the temperature for 2h to form a nucleus emulsion.

[0055] (4) The remaining 25g of ammonium persulfate aqueous solution with a concentration of 2.22% and the third monomer were simultaneously added dropwise into the reactor within 1 hour. The reaction was kept at the temperature for 2 hours to form a core-shell emulsion. The mixture was then cooled naturally, and the pH was adjusted to 7-8 with ammonia water. The mixture was then filtered and discharged.

[0056] (5) Following the same formulation as in Example 1, the product emulsion was prepared into a water-based peelable coating. The coating was sprayed onto a tinplate sheet, and the peel strength and tensile strength were tested after the coating was completely dry.

[0057] Example 3

[0058] (1) Add 0.02 mol glycidyl methacrylate, 0.01 mol amino-terminated silicone oil with an amine value of 0.3 and 0.5 g clean sodium flakes to a single-necked flask, stir and react at room temperature in the dark for 12 h, and filter to obtain double bond modified silicone oil.

[0059] (2) Weigh 40g of methyl methacrylate and 60g of butyl acrylate and mix them. Divide them into two parts in a 1:1 ratio and label them as the second monomer and the first monomer, respectively. Disperse 0.75g of double bond modified silicone oil in the first monomer to obtain the third monomer.

[0060] (3) Heat the 500mL reactor equipped with a stirrer and reflux device to 75℃, and prepare a pre-emulsion by ultrasonic emulsification of the second monomer, 2.67g sodium dodecyl sulfate, 1.33g OP-10 and 50g water. Within 1h, add 21.4g of 7% N,N-methylenebisacrylamide aqueous solution and 50g of 3.34% ammonium persulfate aqueous solution dropwise into the reactor and keep it at the temperature for 2h to form a nucleus emulsion.

[0061] (4) The remaining 25g of 3.34% ammonium persulfate aqueous solution and the third monomer were simultaneously added dropwise into the reactor within 1 hour. The reaction was kept at the temperature for 2 hours to form a core-shell emulsion. The mixture was then cooled naturally, and the pH was adjusted to 7-8 with ammonia water. The mixture was then filtered and discharged.

[0062] (5) Following the same formulation as in Example 1, the product emulsion was prepared into a water-based peelable coating. The coating was sprayed onto a tinplate sheet, and the peel strength and tensile strength were tested after the coating was completely dry.

[0063] This disclosure also provides comparative examples.

[0064] Comparative Example 1

[0065] (1) Weigh 33.34g of methyl methacrylate and 26.66g of butyl acrylate and mix them. Divide them into two parts in a 1:1 ratio and label them as the second monomer and the first monomer, respectively.

[0066] (2) Heat the 250mL reactor equipped with a stirrer and reflux device to 75℃. Prepare a pre-emulsion by ultrasonic emulsification of the second monomer, 1.2g sodium dodecyl sulfate, 0.6g OP-10 and 30g water. Add 6g of 5% N,N-methylenebisacrylamide aqueous solution and 30g of 3.34% ammonium persulfate aqueous solution to the reactor dropwise within 1h. Keep the reaction at the temperature for 2h to form a nucleus emulsion.

[0067] (3) The remaining 15g of 3.34% ammonium persulfate aqueous solution and the third monomer were simultaneously added dropwise into the reactor within 1 hour. The reaction was kept at the temperature for 2 hours to form a core-shell emulsion. The mixture was then cooled naturally, and the pH was adjusted to 7-8 with ammonia water. The mixture was then filtered and discharged.

[0068] (4) Following the same formulation as in Example 1, the product emulsion was prepared into a water-based peelable coating. The coating was sprayed onto a tinplate sheet, and the peel strength and tensile strength were tested after the coating was completely dry.

[0069] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain double bond modified silicone oil, while everything else remains the same.

[0070] Comparative Example 2

[0071] In Comparative Example 2, the amount of calcium carbonate peeling agent in step (4) was changed to 6 parts according to the process formula of Comparative Example 1, while the rest remained unchanged.

[0072] The mechanical properties and peel strength of the coatings prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2 were tested using a universal tensile testing machine. The results are shown in Table 1.

[0073] Table 1. Performance comparison of the peelable emulsions prepared in the examples and comparative examples.

[0074]

[0075] From the perspective of mechanical properties, as shown in Comparative Examples 1 and 2 in Table 1, when the amount of calcium carbonate is doubled, its tensile strength drops sharply by 60%, indicating that excessive calcium carbonate is very detrimental to the mechanical properties of the coating.

[0076] As can be seen from the comparison of Examples 1-3 with Comparative Example 1 in Table 1, the introduction of silicone oil will slightly reduce the mechanical properties of the coating. As the silicone oil content increases, the tensile strength of the coating continues to decrease. When the silicone oil content is 1%, the tensile strength decreases the most, reaching 21%.

[0077] Therefore, increasing the amount of calcium carbonate release agent and silicone oil will reduce tensile strength, but compared with this disclosure, increasing the amount of silicone oil has a smaller negative impact on the mechanical strength of the coating.

[0078] As shown in Table 1, when the amount of calcium carbonate in Comparative Example 2 was doubled, the peel strength of the coating decreased by 32%, with Comparative Example 1 as the control group.

[0079] In Example 2, with the introduction of only 0.5% silicone oil, the coating peel strength decreased sharply by 43%. As the amount of silicone oil was further increased, in Example 3, the amount of silicone oil was 0.75%, and the coating peel strength decreased by 51%. In Example 1, the amount of silicone oil was 1%, and the coating peel strength decreased by 58%.

[0080] This also demonstrates that the introduction of silicone oil in this disclosure can significantly reduce the peel strength of the coating and improve its peelability, with an effect far superior to adding calcium carbonate as a peeling aid.

[0081] Figure 2 A transmission electron microscope image of the core-shell structured peelable emulsion prepared according to exemplary embodiment 1 of this disclosure is shown. The peelable emulsion includes a shell layer 201 and a core layer 202 of the core-shell emulsion. The core layer 202 of the peelable emulsion contains an N,N-methylenebisacrylamide crosslinking network, and the shell layer 201 contains low-polarity silicone oil segments, forming core-shell structured latex particles.

[0082] Based on the above method, this disclosure modifies silicone oil by covalent grafting of the epoxy group of glycidyl methacrylate with the amino-terminated silicone oil, thereby grafting active double bonds onto the silicone oil molecules. Low-polarity silicone oil molecules are introduced into the molecular side chains of polyacrylate by in-situ core-shell emulsion polymerization, reducing the overall polarity of the polyacrylate molecules and weakening its intrinsic adhesion, thereby reducing the amount of release agent required and avoiding the adverse effects of adding too much release agent on mechanical properties.

[0083] On the other hand, core-shell structured latex particles containing N,N-methylenebisacrylamide crosslinking networks in the core and low-polarity silicone oil segments in the shell were prepared by core-shell emulsion polymerization. This not only improved the mechanical properties of the emulsion itself, but also reduced the polarity at the molecular level, effectively improving its peelability.

[0084] The water-based peelable coating prepared using the above-mentioned peelable emulsion has superior mechanical properties and peelability.

[0085] The objectives of this invention have been fully and effectively achieved through the above embodiments. Those skilled in the art will understand that this invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments described above. Although the invention has been described with reference to what is currently considered the most practical and preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments, and any modifications that do not depart from the functional and structural principles of the invention will be included within the scope of the claims.

[0086] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein.

[0087] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A process for the preparation of a peelable emulsion characterized in that, include: Glycidyl methacrylate, amino-terminated silicone oil, and sodium flakes were reacted by stirring in the dark at room temperature, and the mixture was filtered to obtain double-bond modified silicone oil. The vinyl monomer is split into a first monomer and a second monomer, and the double bond modified silicone oil is dispersed in the first monomer to obtain a third monomer; the mass ratio of the double bond modified silicone oil to the vinyl monomer is (1~2):200; the vinyl monomer is a mixture of methyl methacrylate and butyl acrylate; The second monomer, emulsifier, and water are ultrasonically emulsified to prepare a pre-emulsion. The pre-emulsion, the crosslinking monomer aqueous solution, and the first ammonium persulfate aqueous solution are then added to a reaction vessel to form a core-phase emulsion. The crosslinking monomer is N,N-methylenebisacrylamide. The third monomer and the second ammonium persulfate aqueous solution are added dropwise to the core phase emulsion to form a core-shell emulsion; The core-shell emulsion was allowed to cool naturally, and the pH was adjusted to 7-8 with ammonia water. The emulsion was then filtered to obtain a peelable emulsion.

2. The method of preparing a peelable emulsion according to claim 1, characterized in that, The molar ratio of glycidyl methacrylate to amino-terminated silicone oil is (1~2):

1.

3. The method of preparing a peelable emulsion according to claim 1, characterized in that, The mass ratio of methyl methacrylate to butyl acrylate is 1:(0.8~1.5).

4. The method of preparing a peelable emulsion according to claim 1, characterized in that, The emulsifier is a mixture of sodium dodecyl sulfate and OP-10; the mass ratio of sodium dodecyl sulfate to OP-10 is 2:1; the amount of sodium dodecyl sulfate and OP-10 used is 1 to 4% of the mass of the vinyl monomer.

5. The method of preparing a peelable emulsion according to claim 1, characterized in that, The amount of N,N-methylenebisacrylamide used is 0.5-1.5% of the mass of the vinyl monomer; the crosslinking monomer aqueous solution is an aqueous solution of N,N-methylenebisacrylamide, and the concentration of the aqueous solution of N,N-methylenebisacrylamide is 3-7%.

6. The method of preparing a peelable emulsion according to claim 1, characterized in that, The first and second ammonium persulfate aqueous solutions contain the same mass percentage of ammonium persulfate, and the mass of the ammonium persulfate is 2-3% of the mass of the vinyl monomer.

7. The method of preparing a peelable emulsion according to claim 1, characterized in that, The step of adding the pre-emulsion, crosslinking monomer aqueous solution, and ammonium persulfate aqueous solution to the reaction vessel to form a core-phase emulsion includes: The pre-emulsion was added to the reactor and heated to 75°C. The crosslinking monomer aqueous solution and the ammonium persulfate aqueous solution are simultaneously added dropwise to the pre-emulsion within 1 hour, and the reaction is kept at a certain temperature for 2 hours to form the nucleus emulsion.

8. The method of preparing a peelable emulsion according to claim 1, characterized in that, The step of adding the third monomer and the second ammonium persulfate aqueous solution dropwise into the core-phase emulsion to form a core-shell emulsion includes: The third monomer and the second ammonium persulfate aqueous solution are simultaneously added dropwise to the core phase emulsion within 1 hour, and the reaction is maintained at a certain temperature for 2 hours to form the core-shell emulsion.

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