Polyacrylate emulsion for water-based polypropylene engineering plastic paint and preparation method thereof

Abstract

The invention provides a polyacrylate emulsion for water-based polypropylene engineering plastic paint and a preparation method, and belongs to the technical field of acrylic resin. The polyacrylate emulsion is prepared from the following components in parts by mass: 0.05 to 1 part of dioctyl sodium sulfosuccinate; 0.05-1 part by mass of an alkyl alcohol ether sulfate containing an allyl group; 1-4 parts by mass of acrylic polyether phosphate; 38 to 42 parts by mass of butyl methacrylate; 1 to 4 parts by mass of hydroxypropyl methacrylate; 0.1-1 part by mass of acrylic acid; 0.1-1 part by mass of methacrylic acid; 0.1 to 1 part by mass of dodecanethiol; 0.02 to 0.5 part by mass of ammonium persulfate; 1-3 parts by mass of a chlorinated polypropylene emulsion; and 45-55 parts by mass of deionized water. According to the present invention, the ratio of the reaction monomers is designed, and the reaction monomers, the emulsifier, other functional additives and other components are subjected to a synergistic effect so as to form the polyacrylate emulsion with characteristics of good stability, good water resistance, good solvent resistance and good binding property;

Description

Technical Field

[0001] The present invention belongs to the technical field of acrylic resins, and in particular relates to a polyacrylate emulsion for water-based polypropylene engineering plastic paint and a preparation method thereof. Background Art

[0002] Oil-based paints emit a large amount of VOC during their production and use, and cannot adapt to the requirements of environmental development. Therefore, it is necessary to develop other paints with low VOC emissions, such as water-based paints.

[0003] As an important component of water-based paint, the performance of water-based resin ultimately determines the performance of water-based paint. Compared with traditional solvent-based acrylic resin, water-based acrylic resin rarely uses or does not use organic solvents, has the advantages of reducing VOC emissions and being green and environmentally friendly. Water-based industrial paint made with it also has the advantages of low VOC emissions and being green and environmentally friendly during production and use; at the same time, water-based acrylic resin has excellent light, heat and chemical stability and weather resistance, so water-based acrylic resin has become the main direction of the current development of acrylic resin.

[0004] However, the water-based paints or water-based resins currently on the market generally have disadvantages such as poor water resistance, poor solvent resistance, and poor bonding with non-polar engineering plastics. At the same time, the paint film tends to turn white when exposed to water. Summary of the invention

[0005] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a polyacrylate emulsion for water-based polypropylene engineering plastic paint and a preparation method thereof.

[0006] In one aspect of the present disclosure, a polyacrylate emulsion for water-based polypropylene engineering plastic paint is provided, the polyacrylate emulsion comprising: 0.05-1 parts by mass of dioctyl sodium sulfosuccinate; 0.05-1 parts by mass of an allyl-containing alkyl alcohol ether sulfate; 1-4 parts by mass of acrylic acid polyether phosphate; 38-42 parts by mass of butyl methacrylate; 1-4 parts by mass of hydroxypropyl methacrylate; 0.1-1 parts by mass of acrylic acid; 0.1-1 parts by mass of methacrylic acid; 0.1-1 parts by mass of dodecanethiol; 0.02-0.5 parts by mass of ammonium persulfate; 1-3 parts by mass of chlorinated polypropylene emulsion; 45-55 parts by mass of deionized water.

[0007] Another aspect of the present disclosure provides a method for preparing the polyacrylate emulsion for water-based polypropylene engineering plastic paint as described above, the method comprising: S110, placing a mixture of deionized water, all acrylic polyether phosphate emulsifiers, butyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, and dodecanethiol in a stirrer and stirring for 0.1-1 hour to form a monomer pre-emulsion; S120, dividing the ammonium persulfate initiator into two parts, and preparing a first initiator solution and a second initiator solution respectively with deionized water; S130, add deionized water, sodium salt of dioctyl sulfosuccinate emulsifier and allyl-containing alkyl alcohol ether sulfate emulsifier into the reactor, start stirring, heat to the first preset temperature under nitrogen protection, add the monomer pre-emulsion into the reactor for the first time, add the first initiator solution after the temperature stabilizes, keep the temperature for the first preset time, start to drop the monomer pre-emulsion and the second initiator solution for the second time, keep the temperature for the second preset time, add ammonia water and the remaining deionized water, keep the temperature for the third preset time, add the chlorinated polypropylene emulsion, keep the temperature for the fourth preset time, cool down, and filter.

[0008] Optionally, the ammonium persulfate initiator is divided into two parts, and the first initiator solution and the second initiator solution are prepared with deionized water respectively, comprising: The ammonium persulfate is divided into two parts, one part is dissolved in 1-2% deionized water to prepare a first initiator solution, and the other part is dissolved in 9-12% deionized water to prepare a second initiator solution.

[0009] Optionally, in step S110, the content of deionized water is 15-18% of the total amount; and / or, In step S130, the content of deionized water is 60-65% of the total amount.

[0010] Optionally, the content of the monomer pre-emulsion added to the reactor for the first time is 3-8% of its total content; The content of the monomer pre-emulsion added dropwise for the second time is 92-97% of the total content.

[0011] Optionally, the second dropwise addition of the monomer pre-emulsion takes 3-4 hours.

[0012] Optionally, the second initiator solution is added dropwise for 3.1-4.5 hours.

[0013] Optionally, the dripping time of the second initiator solution is 0.1-0.5 hours longer than the dripping time of the monomer pre-emulsion.

[0014] Optionally, the first preset temperature is 70-85°C.

[0015] Optionally, the first preset time is 0.1-0.5 hours; and / or, The second preset time is 1-2 hours; and / or, The third preset time and the fourth preset time are 0.5-1 hour.

[0016] The present disclosure proposes a polyacrylate emulsion for water-based polypropylene engineering plastic paint and a preparation method. The polyacrylate emulsion includes: 0.05-1 parts by mass of dioctyl sodium salt of sulfosuccinate; 0.05-1 parts by mass of allyl-containing alkyl alcohol ether sulfate; 1-4 parts by mass of acrylic acid polyether phosphate; 38-42 parts by mass of butyl methacrylate; 1-4 parts by mass of hydroxypropyl methacrylate; 0.1-1 parts by mass of acrylic acid; 0.1-1 parts by mass of methacrylic acid; 0.1-1 parts by mass of dodecanethiol; 0.02-0.5 parts by mass of ammonium persulfate; 1-3 parts by mass of chlorinated polypropylene emulsion; 45-55 parts by mass of deionized water. The present disclosure designs the ratio of reactive monomers and synergizes each reactive monomer with components such as emulsifiers and other functional additives to form a polyacrylate emulsion with good stability, water resistance, solvent resistance and bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flowchart of a method for preparing a polyacrylate emulsion for water-based polypropylene engineering plastic paint according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0019] In one aspect of the present disclosure, a polyacrylate emulsion for water-based polypropylene engineering plastic paint is provided, comprising: 0.05-1 parts by mass of dioctyl sodium sulfosuccinate; 0.05-1 parts by mass of allyl alkyl alcohol ether sulfate; 1-4 parts by mass of acrylic acid polyether phosphate; 38-42 parts by mass of butyl methacrylate; 1-4 parts by mass of hydroxypropyl methacrylate; 0.1-1 parts by mass of acrylic acid; 0.1-1 parts by mass of methacrylic acid; 0.1-1 parts by mass of dodecanethiol; 0.02-0.5 parts by mass of ammonium persulfate; 1-3 parts by mass of chlorinated polypropylene emulsion; and 45-55 parts by mass of deionized water, with a total amount of 100 parts.

[0020] In this embodiment, dioctyl sodium sulfosuccinate, alkyl alcohol ether sulfate containing allyl groups and acrylic acid polyether phosphate are used as emulsifiers at the same time. Among them, dioctyl sodium sulfosuccinate is used as a non-reactive emulsifier, and has good emulsification. At the same time, compared with ordinary emulsifiers, its molecular chain is longer, the molecular weight is larger, and the amount is smaller, which can greatly reduce the water whitening phenomenon of the paint film. Secondly, alkyl alcohol ether sulfate containing allyl groups and acrylic acid polyether phosphate are used as reactive emulsifiers, containing double bonds and allyl reaction groups, and participate in the reaction like reactive monomers. In the emulsion polymerization process, it can better react with the system monomers, participate in the formation process of the polymer, and be grafted onto the polymer macromolecules, so as to improve the hot water resistance and solvent resistance of the polymer emulsion and the paint film. It will not be free when it meets water, and the water whitening phenomenon will occur, that is, through the complementary effect of non-reactive and reactive emulsifiers, on the one hand, the stability of the emulsion is improved, and on the other hand, the water resistance of the paint film can be effectively improved, and the quality and use effect of the paint film can be guaranteed. Thirdly, by designing the ratio of reactive monomers and synergizing each reactive monomer with components such as emulsifiers and chlorinated polypropylene emulsion additives, a polyacrylate emulsion with good stability, water resistance, solvent resistance and bonding properties is formed.

[0021] In some preferred embodiments, the content of dioctyl sodium sulfosuccinate is preferably 0.05 parts by mass, 0.07 parts by mass, or 1 part by mass. As an important emulsifier, it has an amphiphilic structure, which enables it to be adsorbed on the oil-water interface to play a certain emulsifying role. It also has a good dispersing effect and improves wettability.

[0022] In other preferred embodiments, the content of the allyl-containing alkyl alcohol ether sulfate may preferably be 0.05 parts by mass, 0.07 parts by mass, or 1 part by mass. This component acts as a reactive emulsifier and synergistically with dioctyl sodium sulfosuccinate to improve the emulsification effect. In addition, this component is reactive. During the emulsion polymerization process, the allyl group can participate in the polymerization reaction and react with the monomer, so that the emulsifier molecules can be covalently bonded to the polymer molecular chains to form a stable polymer emulsion, thereby improving the hot water resistance and solvent resistance of the emulsion after film formation.

[0023] It should be noted that the allyl-containing alkyl alcohol ether sulfate of this embodiment is preferably a sodium salt or an ammonium salt. For example, when the ammonium salt is preferred, the structural formula thereof is as follows: , n is 1-3.

[0024] In other preferred embodiments, the content of acrylic polyether phosphate may preferably be 1 part by mass, 2 parts by mass, 3 parts by mass, or 4 parts by mass. This component also acts as a reactive emulsifier, has emulsification and reactivity, and can participate in the polymerization reaction during the emulsion polymerization process, so that the emulsifier molecules can be covalently bonded to the polymer molecular chains to form a stable polymer emulsion, thereby improving the hot water and solvent resistance of the emulsion after film formation, and improving the friction resistance of the paint film.

[0025] In other preferred embodiments, the content of butyl methacrylate may be preferably 38 parts by mass, 39 parts by mass, 40 parts by mass, 41 parts by mass, or 42 parts by mass.

[0026] In other preferred embodiments, the content of hydroxypropyl methacrylate may be preferably 1 part by mass, 2 parts by mass, 3 parts by mass, or 4 parts by mass.

[0027] In other preferred embodiments, the content of acrylic acid may be preferably 0.1 parts by mass, 0.3 parts by mass, 0.5 parts by mass, 0.7 parts by mass, or 1 part by mass.

[0028] In other preferred embodiments, the content of methacrylic acid may be preferably 0.1 parts by mass, 0.3 parts by mass, 0.5 parts by mass, 0.7 parts by mass, or 1 part by mass.

[0029] In this embodiment, butyl methacrylate, hydroxypropyl methacrylate, acrylic acid, and methacrylic acid are used as polymerization monomers to make the plastic paint have good hardness and glossiness.

[0030] In other preferred embodiments, the content of dodecanethiol may preferably be 0.1 parts by mass, 0.3 parts by mass, 0.5 parts by mass, 0.7 parts by mass, or 1 part by mass. This component is used as a chain transfer agent, mainly to control the molecular weight and molecular weight distribution of the polymer so that it meets the expected performance requirements. It can react with the active polymer chain to terminate the growth of the growing polymer chain.

[0031] In other preferred embodiments, the content of ammonium persulfate may preferably be 0.02 parts by mass, 0.03 parts by mass, or 0.05 parts by mass. As an initiator, during the polymerization reaction, ammonium persulfate will decompose when heated or under appropriate reaction conditions to produce sulfate radicals, which can initiate free radical polymerization of the monomers in the emulsion to form a polymer.

[0032] In other preferred embodiments, the content of chlorinated polypropylene emulsion may preferably be 1 part by mass, 2 parts by mass, or 3 parts by mass. This component can combine with the same chemical structure in polyolefin to generate a strong interaction force, thereby playing a role in improving the adhesion of the paint film to the plastic substrate in the plastic paint, improving the film-forming property, and reducing the cost.

[0033] In other preferred embodiments, the content of deionized water may be preferably 45 parts by mass, 47 parts by mass, 50 parts by mass, or 55 parts by mass.

[0034] In this embodiment, the ratio of reactive monomers is designed, and functional additives and reactive emulsifiers are introduced to form an emulsion with good water resistance, solvent resistance and bonding properties. When applied to plastic paint, the paint film also has good adhesion.

[0035] As shown in FIG. 1 , another aspect of the present disclosure provides a method S100 for preparing the aforementioned waterborne polypropylene engineering plastic paint polyacrylate emulsion, which specifically comprises the following steps S110 to S130: S110, putting deionized water, all acrylic polyether phosphate emulsifiers, butyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, and dodecanethiol into a mixed solution, and stirring for 0.1-1 hour to form a monomer pre-emulsion.

[0036] Specifically, in step S110, the content of deionized water is 15-18% of the total amount of deionized water in the formula, that is, 15-18% of 45-55 parts by mass of deionized water is added to step S110.

[0037] S120, dividing the ammonium persulfate initiator into two parts, and preparing a first initiator solution and a second initiator solution respectively with deionized water.

[0038] Specifically, ammonium persulfate is equally divided into two parts, one part is dissolved in 1-2% deionized water to prepare a first initiator solution, and the other part is dissolved in 9-12% deionized water to prepare a second initiator solution.

[0039] S130, add deionized water, sodium salt of dioctyl sulfosuccinate emulsifier and allyl-containing alkyl alcohol ether sulfate emulsifier into the reactor, start stirring, heat to the first preset temperature under nitrogen protection, add the monomer pre-emulsion into the reactor for the first time, add the first initiator solution after the temperature stabilizes, keep the temperature for the first preset time, start to drop the monomer pre-emulsion and the second initiator solution for the second time, keep the temperature for the second preset time, add ammonia water and the remaining deionized water, keep the temperature for the third preset time, add the chlorinated polypropylene emulsion, keep the temperature for the fourth preset time, cool down, and filter.

[0040] Further, in step S130, the amount of deionized water added is 60-65% of the total amount.

[0041] Furthermore, in step S130, the content of the monomer pre-emulsion added to the reactor for the first time is 3-8% of the total content; the content of the monomer pre-emulsion added for the second time is 92-97% of the total content. That is, the monomer pre-emulsion formed in step S110 is divided into two parts, one of which is 3-8% of the total content, which is added to the reaction container for the first time, and the first initiator solution is introduced for reaction, and then the remaining monomer pre-emulsion and the second initiator solution are added to the reaction container for reaction.

[0042] Furthermore, the second dropwise addition of the monomer pre-emulsion takes 3-4 hours, and the second dropwise addition of the initiator solution takes 3.1-4.5 hours.

[0043] It should be understood that in order to make the monomers react better, the second initiator solution is added for 0.1-0.5 hours longer than the monomer pre-emulsion, so that the monomers can react fully when the initiator decomposes to release the initiating groups.

[0044] Furthermore, the first preset temperature is 70-85°C, for example, 70°C, 75°C, 80°C, 85°C, etc.

[0045] Furthermore, the first preset time is 0.1-0.5 hours, for example, 0.1 hours, 0.2 hours, 0.3 hours, 0.4 hours, 0.5 hours, etc.

[0046] Furthermore, the second preset time is 1-2 hours, for example, 1 hour, 1.5 hours, 2 hours, etc.

[0047] Furthermore, the third preset time and the fourth preset time are both 0.5-1 hour, for example, 0.5 hour, 0.7 hour, 1 hour, etc.

[0048] The present invention optimizes the emulsifier components and preparation process parameters to enable the components to work synergistically to form a polyacrylate emulsion with good water resistance, solvent resistance and bonding properties. The preparation method is simple.

[0049] The water-based polypropylene engineering plastic paint formed in this embodiment has good water resistance and solvent resistance, strong bonding with non-polar engineering plastics, and the paint film is not prone to whitening when exposed to water.

[0050] The polyacrylate emulsion and its preparation method will be further described below in conjunction with specific examples: Example 1 A polyacrylate emulsion for water-based polypropylene engineering plastic paint, the raw material components of which are as follows by weight: 0.2 parts of dioctyl sodium sulfosuccinate 0.25 parts of allyl-containing alkyl alcohol ether sulfate 2.5 parts of acrylic acid polyether phosphate 40 parts of butyl methacrylate 2 parts of Hydroxypropyl Methacrylate 0.5 parts of acrylic acid Methacrylic acid 0.5 parts 0.2 parts of dodecanethiol 0.1 part ammonium persulfate 1 part of chlorinated polypropylene emulsion 52.75 parts of deionized water A total of 100 copies.

[0051] Among them, the allyl-containing alkyl alcohol ether sulfate was purchased from Japan Aidi Co., Ltd., SR-1025, and its structural formula is as follows: .

[0052] Furthermore, the preparation method comprises: (1) Monomer pre-emulsion Take 16% of the total amount of deionized water in the above formula, i.e. 8.44 parts, all acrylic polyether phosphate emulsifier, butyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, and dodecanethiol to form a mixed solution, put it into a stirrer and stir for 0.5 hours to make a monomer pre-emulsion for standby use; (2) Preparation of initiator solution The ammonium persulfate initiator is evenly divided into two parts, one part is dissolved in 1.4% of the total amount of deionized water, i.e. 0.7358 parts, to prepare a first initiator solution, and the other part is dissolved in 10% of the total amount of deionized water, i.e. 5.275 parts, to prepare a second initiator solution for standby use; (3) Shell emulsion synthesis process Take 64% of the total amount of deionized water, i.e. 33.76 parts, all the dioctyl sodium salt of sulfosuccinate emulsifier and all the allyl-containing alkyl alcohol ether sulfate emulsifier, add them into a reactor with nitrogen protection, heating, stirring and condensation reflux, start stirring, heat to 80°C under nitrogen protection, take 4% of the monomer pre-emulsion and add it into the reactor, after the temperature stabilizes, add the first initiator solution, keep warm and react for 0.5 hour, start to drop the remaining monomer pre-emulsion and the second initiator solution at the same time, the dropping time is controlled at 3 hours, and the initiator is 0.3 hour longer than the monomer pre-emulsion dropping time. After the dropwise addition is completed, keep warm and react for 1 hour, add ammonia water and the remaining water, keep warm for 0.5 hour, add all the chlorinated polypropylene emulsion, keep warm for 0.5 hour, cool down, and filter.

[0053] Furthermore, the emulsion obtained in Example 1 was used as a polypropylene engineering plastic varnish. After testing, the performance of the paint film was as shown in Table 1. The hardness was H-HB level. There was no whitening under the conditions of immersion in hot water at 40°C for 15 days, immersion in hot water at 70°C for 4 hours, and immersion in hot water at 100°C for 1 hour. The adhesion was level 5, indicating that the paint film in the grid did not fall off at all, and the bonding force between the paint film and the substrate was very strong, which may be due to the formation of good chemical bonding, physical adsorption or mechanical bite between the paint film and the substrate.

[0054] Example 2 A polyacrylate emulsion for water-based polypropylene engineering plastic paint, the raw material components of which are as follows by weight: 0.8 parts of dioctyl sodium sulfosuccinate 0.7 parts of allyl-containing alkyl alcohol ether sulfate 1.5 parts of acrylic acid polyether phosphate Butyl methacrylate 38 parts 4 parts of Hydroxypropyl Methacrylate 0.5 parts of acrylic acid Methacrylic acid 0.5 parts 0.8 parts of dodecanethiol 0.5 parts of ammonium persulfate 3 parts of chlorinated polypropylene emulsion 49.7 parts of deionized water A total of 100 copies.

[0055] Among them, the allyl-containing alkyl alcohol ether sulfate was purchased from Japan Aidi Co., Ltd., SR-1025, and its structural formula is as follows: .

[0056] Furthermore, the preparation method comprises: (1) Monomer pre-emulsion Take 16% of the total amount of deionized water in the above formula, i.e. 7.952 parts, all acrylic polyether phosphate emulsifier, butyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, and dodecanethiol to form a mixed solution, put it into a stirrer and stir for 0.5 hours to make a monomer pre-emulsion for standby use; (2) Preparation of initiator solution The ammonium persulfate initiator is evenly divided into two parts, one part is dissolved in 1.4% of the total amount of deionized water, i.e. 0.696 parts, to prepare a first initiator solution, and the other part is dissolved in 10% of the total amount of deionized water, i.e. 4.97 parts, to prepare a second initiator solution for standby use; (3) Shell emulsion synthesis process Take 64% of the total amount of deionized water, i.e. 31.808 parts, all the dioctyl sodium salt of sulfosuccinate emulsifier and all the allyl-containing alkyl alcohol ether sulfate emulsifier, add them into a reactor with nitrogen protection, heating, stirring and condensation reflux, start stirring, heat to 80°C under nitrogen protection, take 4% of the monomer pre-emulsion and add it into the reactor, after the temperature stabilizes, add the first initiator solution, keep warm and react for 0.5 hour, start to drop the remaining monomer pre-emulsion and the second initiator solution at the same time, the dropping time is controlled at 3 hours, the initiator is 0.3 hour longer than the monomer pre-emulsion dropping time, after the dropping is completed, keep warm and react for 1 hour, add ammonia water and the remaining water, keep warm for 0.5 hour, add all the chlorinated polypropylene emulsion, keep warm for 0.5 hour, cool down, and filter.

[0057] Furthermore, the emulsion obtained in Example 2 was used as a polypropylene engineering plastic varnish. After testing, the performance of the paint film was as shown in Table 1. The hardness was H-HB level. There was no whitening under the conditions of immersion in hot water at 40°C for 15 days, immersion in hot water at 70°C for 4 hours, and immersion in hot water at 100°C for 1 hour. The adhesion was level 5, indicating that the paint film in the grid did not fall off at all, and the bonding force between the paint film and the substrate was very strong, which may be due to the formation of good chemical bonding, physical adsorption or mechanical bite between the paint film and the substrate.

[0058] Example 3 A polyacrylate emulsion for water-based polypropylene engineering plastic paint, the raw material components of which are as follows by weight: 0.2 parts of dioctyl sodium sulfosuccinate 0.25 parts of allyl-containing alkyl alcohol ether sulfate 2.5 parts of acrylic acid polyether phosphate 40 parts of butyl methacrylate 2 parts of Hydroxypropyl Methacrylate 0.5 parts of acrylic acid Methacrylic acid 0.5 parts 0.2 parts of dodecanethiol 0.1 part ammonium persulfate 1 part of chlorinated polypropylene emulsion 52.75 parts of deionized water A total of 100 copies.

[0059] Among them, the allyl-containing alkyl alcohol ether sulfate was purchased from Japan Aidi Co., Ltd., SR-1025, and its structural formula is as follows: .

[0060] Furthermore, the preparation method comprises: (1) Monomer pre-emulsion Take 18% of the total amount of deionized water in the above formula, i.e. 9.495 parts, all acrylic polyether phosphate emulsifier, butyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, and dodecanethiol to form a mixed solution, put it into a stirrer and stir for 0.5 hours to make a monomer pre-emulsion for standby use; (2) Preparation of initiator solution The ammonium persulfate initiator is evenly divided into two parts, one part is dissolved in 2% of the total amount of deionized water, i.e., 1.055 parts, to prepare a first initiator solution, and the other part is dissolved in 12% of the total amount of deionized water, i.e., 6.33 parts, to prepare a second initiator solution for standby use; (3) Shell emulsion synthesis process Take 61% of the total amount of deionized water, i.e. 32.177 parts, all the dioctyl sodium salt of sulfosuccinate emulsifier and all the allyl-containing alkyl alcohol ether sulfate emulsifier, add them into a reactor with nitrogen protection, heating, stirring and condensation reflux, start stirring, heat to 80°C under nitrogen protection, take 6% of the monomer pre-emulsion and add it into the reactor, after the temperature stabilizes, add the first initiator solution, keep warm and react for 0.5 hour, start to drop the remaining monomer pre-emulsion and the second initiator solution at the same time, the dropping time is controlled at 3 hours, the initiator is 0.3 hour longer than the monomer pre-emulsion dropping time, after the dropping is completed, keep warm and react for 1 hour, add ammonia water and the remaining water, keep warm for 0.5 hour, add all the chlorinated polypropylene emulsion, keep warm for 0.5 hour, cool down, and filter.

[0061] Furthermore, the emulsion obtained in Example 3 was used as a polypropylene engineering plastic varnish. After testing, the performance of the paint film was as shown in Table 1. The hardness was H-HB level. There was no whitening under the conditions of immersion in hot water at 40°C for 15 days, immersion in hot water at 70°C for 4 hours, and immersion in hot water at 100°C for 1 hour. The adhesion was level 5, indicating that the paint film in the grid did not fall off at all, and the bonding force between the paint film and the substrate was very strong, which may be due to the formation of good chemical bonding, physical adsorption or mechanical bite between the paint film and the substrate.

[0062] Example 4 A polyacrylate emulsion for water-based polypropylene engineering plastic paint, the raw material components of which are as follows by weight: 0.2 parts of dioctyl sodium sulfosuccinate 0.25 parts of allyl-containing alkyl alcohol ether sulfate 2.5 parts of acrylic acid polyether phosphate 40 parts of butyl methacrylate 2 parts of Hydroxypropyl Methacrylate 0.5 parts of acrylic acid Methacrylic acid 0.5 parts 0.2 parts of dodecanethiol 0.1 part ammonium persulfate 1 part of chlorinated polypropylene emulsion 52.75 parts of deionized water A total of 100 copies.

[0063] Among them, the allyl-containing alkyl alcohol ether sulfate was purchased from Japan Aidi Co., Ltd., SR-1025, and its structural formula is as follows: .

[0064] Furthermore, the preparation method comprises: (1) Monomer pre-emulsion Take 16% of the total amount of deionized water in the above formula, i.e. 8.44 parts, all acrylic polyether phosphate emulsifier, butyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, and dodecanethiol to form a mixed solution, put it into a stirrer and stir for 0.5 hours to make a monomer pre-emulsion for standby use; (2) Preparation of initiator solution The ammonium persulfate initiator is evenly divided into two parts, one part is dissolved in 1.4% of the total amount of deionized water, i.e. 0.7385 parts, to prepare a first initiator solution, and the other part is dissolved in 10% of the total amount of deionized water, i.e. 5.275 parts, to prepare a second initiator solution for standby use; (3) Shell emulsion synthesis process Take 64% of the total amount of deionized water, i.e. 33.76 parts, all the dioctyl sodium salt of sulfosuccinate emulsifier and all the allyl-containing alkyl alcohol ether sulfate emulsifier, add them into a reactor with nitrogen protection, heating, stirring and condensation reflux, start stirring, heat to 78°C under nitrogen protection, take 4% of the monomer pre-emulsion and add it into the reactor, after the temperature stabilizes, add the first initiator solution, keep warm and react for 0.1 hour, start to drop the remaining monomer pre-emulsion and the second initiator solution at the same time, the dropping time is controlled at 4 hours, and the initiator is 0.5 hour longer than the monomer pre-emulsion dropping time. After the dropwise addition is completed, keep warm and react for 2 hours, add ammonia water and the remaining water, keep warm for 1 hour, add all the chlorinated polypropylene emulsion, keep warm for 1 hour, cool down, and filter.

[0065] Furthermore, the emulsion obtained in Example 4 was used as a polypropylene engineering plastic varnish. After testing, the performance of the paint film was as shown in Table 1. The hardness was H-HB level. There was no whitening under the conditions of immersion in hot water at 40°C for 15 days, immersion in hot water at 70°C for 4 hours, and immersion in hot water at 100°C for 1 hour. The adhesion was level 5, indicating that the paint film in the grid did not fall off at all, and the bonding force between the paint film and the substrate was very strong, which may be due to the formation of good chemical bonding, physical adsorption or mechanical bite between the paint film and the substrate.

[0066] Comparative Example 1 A polyacrylate emulsion for water-based polypropylene engineering plastic paint, the raw material components of which are as follows by weight: 2.95 parts of dioctyl sodium sulfosuccinate 40 parts of butyl methacrylate 2 parts of Hydroxypropyl Methacrylate 0.5 parts of acrylic acid Methacrylic acid 0.5 parts 0.2 parts of dodecanethiol 0.1 part ammonium persulfate 1 part of chlorinated polypropylene emulsion 52.75 parts of deionized water A total of 100 copies.

[0067] Furthermore, the preparation method of the emulsion of this comparative example 1 is the same as that of Example 1, and the obtained emulsion is used as a polypropylene engineering plastic varnish. After testing, the performance of the paint film is shown in Table 1. The hardness is H-HB level, whitening occurs under the conditions of immersion in hot water at 40°C for 15 days, immersion in hot water at 70°C for 4 hours, and immersion in hot water at 100°C for 1 hour, and the adhesion is level 3, which means that the adhesion decreases. This shows that when the emulsifier uses a single sodium salt of dioctyl sulfosuccinate, although the polyacrylate emulsion can be stably prepared, its water resistance decreases significantly.

[0068] Comparative Example 2 A polyacrylate emulsion for water-based polypropylene engineering plastic paint, the raw material components of which are as follows by weight: 0.45 parts of allyl-containing alkyl alcohol ether sulfate 2.5 parts of acrylic acid polyether phosphate 40 parts of butyl methacrylate 2 parts of Hydroxypropyl Methacrylate 0.5 parts of acrylic acid Methacrylic acid 0.5 parts 0.2 parts of dodecanethiol 0.1 part ammonium persulfate 1 part of chlorinated polypropylene emulsion 52.75 parts of deionized water A total of 100 copies.

[0069] Among them, the allyl-containing alkyl alcohol ether sulfate was purchased from Japan Aidi Co., Ltd., SR-1025, and its structural formula is as follows: .

[0070] Furthermore, the emulsion preparation method of this comparative example 2 is the same as that of Example 1. Demulsification occurs during the synthesis process, and the target polyacrylate emulsion cannot be prepared normally, indicating that the allyl-containing alkyl alcohol ether sulfate and acrylic polyether phosphate have poor emulsification properties, and the dioctyl sodium salt of sulfosuccinate has good emulsification properties. Combining Examples 1-4 and Comparative Examples 1-2, the dioctyl sodium salt of sulfosuccinate, the allyl-containing alkyl alcohol ether sulfate, and the acrylic polyether phosphate have a synergistic effect, providing emulsification stability and water resistance.

[0071] Comparative Example 3 A polyacrylate emulsion for water-based polypropylene engineering plastic paint, the raw material components of which are as follows by weight: 0.2 parts of dioctyl sodium sulfosuccinate 0.25 parts of allyl-containing alkyl alcohol ether sulfate 2.5 parts of acrylic acid polyether phosphate 40 parts of butyl methacrylate 2 parts of Hydroxypropyl Methacrylate 0.5 parts of acrylic acid Methacrylic acid 0.5 parts 0.2 parts of dodecanethiol 0.1 part ammonium persulfate 53.75 parts of deionized water A total of 100 copies.

[0072] Among them, the allyl-containing alkyl alcohol ether sulfate was purchased from Japan Aidi Co., Ltd., SR-1025, and its structural formula is as follows: .

[0073] Furthermore, the preparation method of the emulsion in this comparative example 3 is the same as that in Example 1, and the obtained emulsion is used as a polypropylene engineering plastic varnish. After testing, the performance of the paint film is shown in Table 1, the hardness is H-HB level, there is no whitening under the conditions of immersion in hot water at 40°C for 15 days, immersion in hot water at 70°C for 4 hours, and immersion in hot water at 100°C for 1 hour, and the adhesion is level 4. It shows that the chlorinated polypropylene emulsion can improve the adhesion of the paint film to the plastic substrate and improve the film-forming property.

[0074] Table 1 Test results of paint film properties of various embodiments and comparative examples

[0075] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A polyacrylate emulsion for water-based polypropylene engineering plastic paint, characterized in that: The polyacrylate emulsion comprises: 0.05-1 parts by mass of dioctyl sodium sulfosuccinate; 0.05-1 parts by mass of an allyl-containing alkyl alcohol ether sulfate; 1-4 parts by mass of acrylic acid polyether phosphate; 38-42 parts by mass of butyl methacrylate; 1-4 parts by mass of hydroxypropyl methacrylate; 0.1-1 parts by mass of acrylic acid; 0.1-1 parts by mass of methacrylic acid; 0.1-1 parts by mass of dodecanethiol; 0.02-0.5 parts by mass of ammonium persulfate; 1-3 parts by mass of chlorinated polypropylene emulsion; 45-55 parts by mass of deionized water.

2. A method for preparing the polyacrylate emulsion for water-based polypropylene engineering plastic paint as claimed in claim 1, characterized in that: The method comprises: S110, placing a mixture of deionized water, all acrylic polyether phosphate emulsifiers, butyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, and dodecanethiol in a stirrer and stirring for 0.1-1 hour to form a monomer pre-emulsion; S120, dividing the ammonium persulfate initiator into two parts, and preparing a first initiator solution and a second initiator solution respectively with deionized water; S130, add deionized water, sodium salt of dioctyl sulfosuccinate emulsifier and allyl-containing alkyl alcohol ether sulfate emulsifier into the reactor, start stirring, heat to the first preset temperature under nitrogen protection, add the monomer pre-emulsion into the reactor for the first time, add the first initiator solution after the temperature stabilizes, keep the temperature for the first preset time, start to drop the monomer pre-emulsion and the second initiator solution for the second time, keep the temperature for the second preset time, add ammonia water and the remaining deionized water, keep the temperature for the third preset time, add the chlorinated polypropylene emulsion, keep the temperature for the fourth preset time, cool down, and filter.

3. The method according to claim 2, characterized in that The ammonium persulfate initiator is divided into two parts, and the first initiator solution and the second initiator solution are prepared with deionized water respectively, comprising: The ammonium persulfate is divided into two parts, one part is dissolved in 1-2% deionized water to prepare a first initiator solution, and the other part is dissolved in 9-12% deionized water to prepare a second initiator solution.

4. The method according to claim 2, characterized in that: In step S110, the content of deionized water is 15-18% of the total amount; and / or, In step S130, the content of deionized water is 68-75% of the total amount.

5. The method according to claim 2, characterized in that: The content of the monomer pre-emulsion added to the reactor for the first time is 3-8% of its total content; The content of the monomer pre-emulsion added dropwise for the second time is 92-97% of the total content.

6. The method according to claim 2, characterized in that The time for the second dropwise addition of the monomer pre-emulsion is 3-4 hours.

7. The method according to claim 2, characterized in that The time for adding the second initiator solution dropwise is 3.1-4.5 hours.

8. The method according to claim 2, characterized in that: The dripping time of the second initiator solution is 0.1-0.5 hours longer than the dripping time of the monomer pre-emulsion.

9. The method according to claim 2, characterized in that: The first preset temperature is 70-85°C.

10. The method according to claim 2, characterized in that The first preset time is 0.1-0.5 hours; and / or, The second preset time is 1-2 hours; and / or, The third preset time and the fourth preset time are 0.5-1 hour.

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