Highly permeable hydroxyl acrylic emulsion, its preparation method and application

Abstract

The application belongs to the field of coating and particularly relates to a high-permeability hydroxyl acrylic emulsion, a preparation method and application thereof. The high-permeability hydroxyl acrylic emulsion is prepared from the following raw materials by weight: 2-4 parts of emulsifying functional monomer, 4-6 parts of hydroxyl monomer, 1-2 parts of carboxyl monomer, 14-16 parts of soft monomer, 18-20 parts of hard monomer, 0.5-0.6 parts of chain transfer agent, 1.5-2 parts of neutralizing agent, 0.03-0.05 parts of oxidizing agent, 0.01-0.03 parts of reducing agent, 0.06-0.08 parts of initiator and 54-56 parts of solvent. The high-permeability hydroxyl acrylic emulsion has better permeability and warm wood effect compared with the prior art. In addition, the paint film obtained from the emulsion has good quick-drying property, gloss, hardness and water and chemical resistance, and has excellent comprehensive effect.

Description

Technical Field

[0001] This invention belongs to the field of coating, specifically relating to a high-transparency hydroxy acrylic emulsion, its preparation method, and its application. Background Technology

[0002] Water-based wood coatings have gained popularity due to their environmental friendliness, as they use water as a solvent. Acrylic emulsions, as a key resin in water-based wood coatings, are characterized by low cost, good weather resistance, high gloss, and environmental friendliness. In practical applications, to meet the high-performance requirements of wood coatings, such as high hardness, high water and chemical resistance, researchers have also developed hydroxyl acrylic emulsions (referred to as "hydroxypropyl emulsions").

[0003] However, in some market applications, water-based wood coatings require clear varnishes with good wet film transparency to achieve a better warm wood effect; but the hydroxypropyl emulsions commonly found on the market have a milky white appearance and poor transparency, which cannot meet the requirements for a good warm wood effect.

[0004] The invention patent with publication number CN106560494A provides a hydroxy acrylic emulsion for outdoor water-based wood coatings and its preparation method, which mainly solves the problem that the crosslinking density of acrylic emulsion paint film is low and the overall performance of the paint film is poor, which cannot meet the requirements of outdoor wood coating. The invention patent with publication number CN108003303A provides a water-based hydroxy acrylic resin emulsion for wood coatings and its preparation method, which mainly solves the problem of low paint film hardness. The literature "Synthesis of Hydroxy Acrylic Emulsion and Its Application in Water-based Wood Coatings" mainly solves the problem of high hardness, high toughness and other high performance of wood coatings.

[0005] Since the existing technology does not address how to solve the problem of warm wood effect, the present invention is proposed. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention provides a highly permeable hydroxy acrylic emulsion, which is made from the following raw materials in parts by weight: 2-4 parts of emulsifying functional monomer, 4-6 parts of hydroxy monomer, 1-2 parts of carboxyl monomer, 14-16 parts of soft monomer, 18-20 parts of hard monomer, 0.5-0.6 parts of chain transfer agent, 1.5-2 parts of neutralizing agent, 0.03-0.05 parts of oxidizing agent, 0.01-0.03 parts of reducing agent, 0.06-0.08 parts of initiator, and 54-56 parts of solvent.

[0007] Preferably, the emulsifying functional monomer is one of allyl polyoxyethylene ether ammonium sulfate and allyl polyoxyethylene ether sodium sulfate;

[0008] And / or, the hydroxy monomer is one of hydroxyethyl acrylate and hydroxyethyl methacrylate;

[0009] And / or, the carboxyl monomer is one of acrylic acid and methacrylic acid.

[0010] Preferably, the soft monomer is one of butyl acrylate and isooctyl acrylate;

[0011] And / or, the hard monomer is one of methyl methacrylate and butyl methacrylate.

[0012] Preferably, the chain transfer agent is one of n-octyl mercaptan and n-dodecyl mercaptan;

[0013] And / or, the neutralizing agent is one of ammonia, diethanolamine, triethylamine, or AMP-95;

[0014] And / or, the oxidant is tert-butyl hydroperoxide;

[0015] And / or, the reducing agent is one of sodium formaldehyde sulfoxylate, ascorbic acid, and FF6M;

[0016] And / or, the initiator is one of ammonium persulfate, sodium persulfate, and potassium persulfate.

[0017] Based on the same technical concept, another aspect of the present invention is to provide a method for preparing a highly permeable hydroxy acrylic emulsion, the preparation method comprising the following steps:

[0018] (1) Mix and heat a portion of emulsifying functional monomers, a portion of hydroxyl monomers, a portion of carboxyl monomers, a portion of soft monomers, a portion of hard monomers and a portion of solvent, and then add a portion of initiator to initiate polymerization. After completion, a seed emulsion is obtained.

[0019] (2) The remaining emulsifying functional monomers, the remaining hydroxyl monomers, the remaining carboxyl monomers, some soft monomers, some hard monomers, chain transfer agents and some solvents are stirred and mixed to obtain an emulsion;

[0020] (3) The emulsion and the remaining initiator are simultaneously added dropwise to the seed emulsion. After the polymerization reaction is completed, a neutralizing agent is added dropwise to obtain the reaction emulsion.

[0021] (4) The remaining soft monomer, the remaining hard monomer, the oxidant and the reducing agent are added dropwise to the reaction emulsion in batches. After the polymerization is completed, a high-permeability hydroxy acrylic emulsion is obtained.

[0022] To facilitate understanding of the preparation method, the following explanation is provided:

[0023] The preparation method of this invention mainly consists of two steps. The first step is to prepare a hydrophilic polymeric acrylate copolymer emulsion, which is achieved by copolymerizing monomers containing carboxyl and hydroxyl groups and functional monomers using a soap-free emulsion polymerization method to prepare a macromolecular acrylate copolymer emulsion with a certain emulsifying ability. The second step is to prepare a core-shell type hydroxyl acrylate copolymer emulsion, which involves adding hydrophobic monomers such as methyl methacrylate and butyl acrylate to the hydrophilic polymeric acrylate copolymer emulsion obtained in the first step, stirring and emulsifying for a certain period of time, and then initiating polymerization to form a highly permeable hydroxyl acrylate copolymer emulsion with a hydrophobic monomer as the core and a hydrophilic monomer as the shell. The process flow diagram is shown below. Figure 1 As shown.

[0024] Preferably, in step (1), the heating temperature is 72-75°C;

[0025] And / or, in step (1), the polymerization temperature is 79-81°C and the polymerization time is 30-40 min.

[0026] Preferably, in step (3), the emulsion is added over a time of 60-65 minutes, and the initiator is added over a time of 70-75 minutes.

[0027] And / or, in step (3), the polymerization temperature is 79–81°C.

[0028] Preferably, in step (4), the polymerization temperature is 65-68°C.

[0029] Based on the same technical concept, the present invention provides another application of a high-permeability hydroxy acrylic emulsion as a water-based wood coating.

[0030] The beneficial effects of this invention are as follows:

[0031] 1. The high-transparency hydroxy acrylic emulsion of the present invention has better transparency and warm wood effect compared with the prior art; in addition, the paint film obtained by the emulsion has good quick-drying properties, gloss, hardness and water and chemical resistance, and the overall effect is excellent.

[0032] 2. The preparation method of this invention combines soap-free emulsion polymerization technology with core-shell emulsion polymerization process, and scientifically selects raw materials to design the latex particle structure, specifically as follows:

[0033] The design and preparation of core-shell latex particles containing hydrophilic acrylate copolymers encapsulating hydrophobic acrylate copolymers are described. The hydrophilic acrylate copolymers are hydrophilic polymers containing carboxyl and hydroxyl groups in their molecular chains, exhibiting certain emulsifying and dispersing effects and effectively emulsifying acrylate monomers. The hydrophobic acrylate copolymers, on the other hand, are polymers without hydrophilic groups such as carboxyl and hydroxyl groups in their molecular chains. They can be encapsulated by the hydrophilic polymer, facilitating the formation of a well-defined core-shell structure emulsion, resulting in a fine-particle-size, highly permeable emulsion. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a process flow diagram for the preparation of highly permeable hydroxyacrylic acid emulsion.

[0036] Figure 2 These are appearance diagrams of the high-permeability hydroxy acrylic emulsions obtained in Examples 1 to 3 (from left to right: Example 1, Example 2, Example 3).

[0037] Figure 3 These are the appearance images of the highly permeable hydroxy acrylic emulsions obtained in Comparative Examples 1 and 2 (from left to right: Comparative Example 1 and Comparative Example 2).

[0038] Figure 4 This is a particle size and distribution diagram of the high-permeability hydroxyacrylic acid emulsion obtained in Example 1.

[0039] Figure 5 This is a particle size and distribution diagram of the high-permeability hydroxyacrylic acid emulsion obtained in Example 2.

[0040] Figure 6 This is a particle size and distribution diagram of the high-permeability hydroxyacrylic acid emulsion obtained in Example 3.

[0041] Figure 7 This is a particle size and distribution diagram of the high-permeability hydroxyacrylic acid emulsion obtained in Comparative Example 1.

[0042] Figure 8 This is a particle size and distribution diagram of the high-permeability hydroxy acrylic emulsion obtained in Comparative Example 2. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0044] Example 1

[0045] This embodiment provides a method for preparing a high-permeability hydroxy acrylic emulsion, the preparation method being as follows:

[0046] (1) Weigh 1 / 3 of allyl polyoxyethylene ether ammonium sulfate, 1 / 20 of hydroxyethyl acrylate, 1 / 20 of acrylic acid, 1 / 30 of methyl methacrylate, 1 / 149 of butyl acrylate, and 2 / 3 of deionized water, then mix them in a reactor, turn on the stirring and heat to 72°C, then add 2 / 7 of ammonium persulfate, control the system temperature to be maintained at 79°C and continue polymerization for 30 min to obtain seed emulsion;

[0047] (2) Weigh 2 / 3 of allyl polyoxyethylene ether ammonium sulfate, 19 / 20 of hydroxyethyl acrylate, 19 / 20 of acrylic acid, 19 / 30 of methyl methacrylate, 18 / 149 of butyl acrylate, n-octyl mercaptan, and 1 / 6 of deionized water, and then mix them in a monomer reactor to obtain an emulsion; mix 5 / 7 of ammonium persulfate and 1 / 17 of deionized water in an initiator reactor to obtain an initiator solution;

[0048] (3) Continue to maintain the temperature of 79°C, and simultaneously add the emulsion and initiator solution to the seed emulsion. The emulsion is added in 60 minutes and the initiator solution is added in 70 minutes. After the materials are added, keep warm for 30 minutes. After the warming is completed, add ammonia water (in 30 minutes) to adjust the pH value to 8.5-8.8, raise the temperature to 84°C and keep warm for 2 hours to obtain the reaction emulsion;

[0049] (4) Weigh 1 / 3 of methyl methacrylate and 130 / 149 of butyl acrylate, mix them to obtain a monomer mixture; mix tert-butyl hydroperoxide with 1 / 56 of deionized water to obtain an oxidizing agent solution; mix sodium formaldehyde sulfoxylate with 1 / 56 of deionized water to obtain a reducing agent solution.

[0050] (5) Reduce the temperature of the reaction emulsion to 65°C, increase the stirring speed, and slowly add 1 / 2 of the monomer mixture (add all in 30 min). After the addition is completed, keep stirring for 30 min. Then, simultaneously add 1 / 2 of the oxidant solution and 1 / 2 of the reducing agent solution (add all in 30 min). Control the temperature at 65°C and keep it at 30 min. Repeat the above operation to add the remaining material. After the addition is completed, keep it at 65°C for 60 min. Finally, cool it down to below 40°C and filter it through a 200-mesh filter to obtain the high-permeability hydroxy acrylic emulsion.

[0051] The types and weights of raw materials used in this embodiment are shown in Table 1.

[0052] Table 1

[0053] Deionized water 55.5g Allyl polyoxyethylene ether ammonium sulfate 3g ammonium persulfate 0.08g Hydroxyethyl acrylate 5g acrylic acid 1.5g Butyl acrylate 15g Methyl methacrylate 18g n-Octamethrin 0.5g ammonia 1.5g tert-butyl hydroperoxide 0.05g Sodium formaldehyde sulfoxylate 0.02g

[0054] Example 2

[0055] This embodiment provides a method for preparing a high-permeability hydroxy acrylic emulsion, the preparation method being as follows:

[0056] (1) Weigh 1 / 3 of sodium allyl polyoxyethylene ether sulfate, 1 / 20 of hydroxyethyl methacrylate, 1 / 20 of methacrylic acid, 1 / 30 of butyl methacrylate, 1 / 149 of butyl acrylate, and 2 / 3 of deionized water, then mix them in a reactor, turn on the stirring and heat to 75°C, then add 2 / 7 of sodium persulfate, control the system temperature to 81°C and continue polymerization for 40 min to obtain seed emulsion;

[0057] (2) Weigh 2 / 3 of allyl polyoxyethylene ether sodium sulfate, 19 / 20 of hydroxyethyl methacrylate, 19 / 20 of methacrylic acid, 19 / 30 of butyl methacrylate, 18 / 149 of butyl acrylate, n-dodecyl mercaptan, and 1 / 6 of deionized water, and then mix them in a monomer reactor to obtain an emulsion; mix 5 / 7 of sodium persulfate and 1 / 17 of deionized water in an initiator reactor to obtain an initiator solution;

[0058] (3) Continue to maintain the temperature at 81°C, and simultaneously add the emulsion and initiator solution to the seed emulsion. The emulsion is added in 65 minutes and the initiator solution is added in 75 minutes. After the materials are added, keep warm for 30 minutes. After the warming is completed, add diethanolamine (in 30 minutes). Adjust the pH value to 8.5-8.8, raise the temperature to 84°C and keep warm for 2 hours to obtain the reaction emulsion.

[0059] (4) Weigh 1 / 3 of butyl methacrylate and 130 / 149 of butyl acrylate, mix them to obtain a monomer mixture; mix tert-butyl hydroperoxide with 1 / 56 of deionized water to obtain an oxidizing agent solution; mix ascorbic acid with 1 / 56 of deionized water to obtain a reducing agent solution.

[0060] (5) Reduce the temperature of the reaction emulsion to 68°C, increase the stirring speed, and slowly add 1 / 2 of the monomer mixture (add all in 30 min). After the addition is completed, keep stirring for 30 min. Then, add 1 / 2 of the oxidant solution and 1 / 2 of the reducing agent solution simultaneously (add all in 30 min). Control the temperature at 68°C and keep it at 30 min. Repeat the above operation to add the remaining material. After the addition is completed, keep it at 68°C for 60 min. Finally, cool it down to below 40°C and filter it through a 200-mesh filter to obtain the high-permeability hydroxy acrylic emulsion.

[0061] The types and weights of raw materials used in this embodiment are shown in Table 2.

[0062] Table 2

[0063]

[0064]

[0065] Example 3

[0066] This embodiment provides a method for preparing a high-permeability hydroxy acrylic emulsion, the preparation method being as follows:

[0067] (1) Weigh 1 / 3 of allyl polyoxyethylene ether ammonium sulfate, 1 / 20 of hydroxyethyl acrylate, 1 / 20 of methacrylic acid, 1 / 30 of methyl methacrylate, 1 / 149 of isooctyl acrylate, and 2 / 3 of deionized water, then mix them in a reactor, turn on the stirring and heat to 75°C, then add 2 / 7 of potassium persulfate, control the system temperature to 81°C and continue polymerization for 40 min to obtain seed emulsion;

[0068] (2) Weigh 2 / 3 of allyl polyoxyethylene ether ammonium sulfate, 19 / 20 of hydroxyethyl acrylate, 19 / 20 of methacrylic acid, 19 / 30 of methyl methacrylate, 18 / 149 of isooctyl acrylate, n-dodecyl mercaptan, and 1 / 6 of deionized water, and then mix them in a monomer reactor to obtain an emulsion; mix 5 / 7 of potassium persulfate and 1 / 17 of deionized water in an initiator reactor to obtain an initiator solution;

[0069] (3) Continue to maintain the temperature at 81°C, and simultaneously add the emulsion and initiator solution to the seed emulsion. The emulsion is added in 65 minutes and the initiator solution is added in 75 minutes. After the materials are added, keep warm for 30 minutes. After the warming is completed, add triethylamine (in 30 minutes). Adjust the pH value to 8.5-8.8, raise the temperature to 84°C and keep warm for 2 hours to obtain the reaction emulsion.

[0070] (4) Weigh 1 / 3 of methyl methacrylate and 130 / 149 of isooctyl acrylate, mix them to obtain a monomer mixture; mix tert-butyl hydroperoxide with 1 / 56 of deionized water to obtain an oxidizing agent solution; mix FF6M with 1 / 56 of deionized water to obtain a reducing agent solution.

[0071] (5) Reduce the temperature of the reaction emulsion to 68°C, increase the stirring speed, and slowly add 1 / 2 of the monomer mixture (add all in 30 min). After the addition is completed, keep stirring for 30 min. Then, add 1 / 2 of the oxidant solution and 1 / 2 of the reducing agent solution simultaneously (add all in 30 min). Control the temperature at 68°C and keep it at 30 min. Repeat the above operation to add the remaining material. After the addition is completed, keep it at 68°C for 60 min. Finally, cool it down to below 40°C and filter it through a 200-mesh filter to obtain the high-permeability hydroxy acrylic emulsion.

[0072] The types and weights of the raw materials used in this embodiment are shown in Table 3.

[0073] Table 3

[0074] Deionized water 54.9g Allyl polyoxyethylene ether ammonium sulfate 4g Potassium persulfate 0.08g Hydroxyethyl acrylate 5g methacrylic acid 2g Isooctyl acrylate 14g Methyl methacrylate 18g n-Dodecylthiol 0.6g Triethylamine 1.5g tert-butyl hydroperoxide 0.04g FF6M 0.02g

[0075] Comparative Example 1

[0076] This comparative example modifies Example 1 using traditional emulsion preparation technology, as follows:

[0077] (1) In a pre-emulsification kettle, dissolve 2 / 3 of the allyl polyoxyethylene ether ammonium sulfate in 9 / 25 of the deionized water, and then add hydroxyethyl acrylate, acrylic acid, butyl acrylate, methyl methacrylate and n-octyl mercaptan in sequence. Stir at 600 rpm for 30 min and then reduce the stirring speed to 100 rpm. Set aside for use.

[0078] (2) In the initiator tank, dissolve ammonium persulfate in 1 / 10 of the deionized water and set aside for later use;

[0079] (3) Add 23 / 50 of deionized water and 1 / 3 of allyl polyoxyethylene ether ammonium sulfate to the reactor in sequence, start stirring and heat up. When the temperature reaches 80℃, pump 3 / 100 of the total amount of pre-emulsion liquid from the pre-emulsion tank into the reactor. Stir for 10 min, then pump 1 / 50 of the total amount of initiator solution from the initiator tank into the reactor. At the same time, control the temperature to 85℃ and keep it at that temperature for 30 min. Keep the temperature at 85℃±1℃, and then add the materials from the pre-emulsion tank and the initiator tank dropwise. The pre-emulsion liquid is added dropwise over 180 min, and the initiator solution is added dropwise over 185 min. Keep it at that temperature for 60 min. Cool down to 65℃, mix tert-butyl hydrogen peroxide with 1 / 25 of deionized water as an oxidant solution, and mix sodium formaldehyde sulfoxylate with 1 / 25 of deionized water as a reducing agent solution. Add the oxidant solution and the reducing agent solution dropwise at the same time. The dropwise addition is completed in 15 min. Keep it at 65℃ for 30 min.

[0080] (4) Cool down to below 40℃ and filter out the material through a 200-mesh filter.

[0081] The types and weights of raw materials used in this comparative example are shown in Table 4.

[0082] Table 4

[0083]

[0084]

[0085] Comparative Example 2

[0086] In this comparative example, the hydrophilic monomer hydroxyethyl acrylate in the shell of Example 1 was partitioned into the core, as follows:

[0087] (1) Weigh 1 / 3 of allyl polyoxyethylene ether ammonium sulfate, 1 / 20 of acrylic acid, 1 / 30 of methyl methacrylate, 1 / 50 of butyl acrylate, and 2 / 3 of deionized water, then mix them in a reactor, turn on the stirring and heat to 72°C, then add 2 / 7 of ammonium persulfate, control the system temperature to 79°C and continue polymerization for 30 min to obtain seed emulsion;

[0088] (2) Weigh 2 / 3 of allyl polyoxyethylene ether ammonium sulfate, 19 / 20 of acrylic acid, 19 / 30 of methyl methacrylate, 22 / 50 of butyl acrylate, n-octyl mercaptan, and 1 / 6 of deionized water, and then mix them in a monomer reactor to obtain an emulsion; mix 5 / 7 of ammonium persulfate and 1 / 17 of deionized water in an initiator reactor to obtain an initiator solution;

[0089] (3) Continue to maintain the temperature of 79°C, and simultaneously add the emulsion and initiator solution to the seed emulsion. The emulsion is added in 60 minutes and the initiator solution is added in 70 minutes. After the materials are added, keep warm for 30 minutes. After the warming is completed, add ammonia water (in 30 minutes) to adjust the pH value to 8.5-8.8, raise the temperature to 84°C and keep warm for 2 hours to obtain the reaction emulsion;

[0090] (4) Weigh 1 / 3 of methyl methacrylate, 27 / 50 of butyl acrylate and hydroxyethyl acrylate, mix them to obtain a monomer mixture; mix tert-butyl hydroperoxide with 1 / 56 of deionized water to obtain an oxidizing agent solution; mix sodium formaldehyde sulfoxylate with 1 / 56 of deionized water to obtain a reducing agent solution.

[0091] (5) Reduce the temperature of the reaction emulsion to 65°C, increase the stirring speed, and slowly add 1 / 2 of the monomer mixture (add all in 30 min). After the addition is completed, keep stirring for 30 min. Then, simultaneously add 1 / 2 of the oxidant solution and 1 / 2 of the reducing agent solution (add all in 30 min). Control the temperature at 65°C and keep it at 30 min. Repeat the above operation to add the remaining material. After the addition is completed, keep it at 65°C for 60 min. Finally, cool it down to below 40°C and filter it through a 200-mesh filter.

[0092] The types and weights of raw materials used in this comparative example are shown in Table 5.

[0093] Table 5

[0094] Deionized water 55.5g Allyl polyoxyethylene ether ammonium sulfate 3g ammonium persulfate 0.08g Hydroxyethyl acrylate 5g acrylic acid 1.5g Butyl acrylate 15g Methyl methacrylate 18g n-Octamethrin 0.5g ammonia 1.5g tert-butyl hydroperoxide 0.05g Sodium formaldehyde sulfoxylate 0.02g

[0095] Verification Example

[0096] Test method reference: The test methods are in accordance with the standards of "GB / T11175-2002 Test Method for Synthetic Resin Emulsion", "GB / T23999-2009 Waterborne Wood Coatings for Interior Decoration and Renovation" and "GB / T33394-2016 Waterborne Wood Coatings for Children's Room Decoration".

[0097] (a) The emulsions obtained in Examples 1-3 and Comparative Examples 1-2 were tested, and the results are shown in Table 6.

[0098] Table 6

[0099]

[0100] From Table 6 and the image data, we can see that:

[0101] Figure 2 The images show the appearance of the emulsions obtained in Examples 1-3. The emulsions are in a good semi-transparent state.

[0102] Figure 3The images show the appearance of the emulsions obtained in Comparative Examples 1 and 2. The emulsions exhibit poor transparency and are milky white. This is because Comparative Example 1 uses traditional emulsion preparation techniques and does not involve particle design for the polymerization of hydrophilic and hydrophobic monomers, specifically placing the hydroxyl and carboxyl monomers within the shell monomer. Typically, to ensure emulsion stability, hydrophilic and hydrophobic monomers are copolymerized together. This results in latex particles without a clear hydrophilic / hydrophobic distribution, leading to an opaque emulsion appearance. In Comparative Example 2, when hydrophilic monomers are distributed within the core for polymerization, on one hand, the hydrophilic monomers polymerize in the aqueous solution, and the nucleation in the aqueous phase broadens the latex particle distribution. On the other hand, the distribution of hydrophilic monomers on the polymer chains of the core monomers may cause the latex particles to flip or deform, resulting in irregular latex particles and an opaque emulsion appearance.

[0103] Figures 4-8 The figures show the particle size distribution of the emulsions obtained in Examples 1-3 and Comparative Examples 1-2, respectively. As can be seen from the figures, the emulsions obtained in Examples 1-3 have small particle sizes and narrow distributions, and the emulsions are uniform. In contrast, the emulsions obtained in Comparative Examples 1-2 have larger particle sizes and wider distributions, and the large-sized particles initially show obvious characteristic peaks, indicating that agglomeration has already occurred.

[0104] (ii) The emulsions obtained in Examples 1-3 and Comparative Examples 1-2 were directly applied as water-based wood coatings, and the coating film performance was tested, as shown in Table 7.

[0105] Table 7

[0106]

[0107] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A highly permeable hydroxy acrylic emulsion, characterized in that, It is made from the following raw materials in parts by weight: 2-4 parts emulsifying functional monomer, 4-6 parts hydroxyl monomer, 1-2 parts carboxyl monomer, 14-16 parts soft monomer, 18-20 parts hard monomer, 0.5-0.6 parts chain transfer agent, 1.5-2 parts neutralizing agent, 0.03-0.05 parts oxidizing agent, 0.01-0.03 parts reducing agent, 0.06-0.08 parts initiator, and 54-56 parts solvent; The emulsifying functional monomer is one of allyl polyoxyethylene ether ammonium sulfate and allyl polyoxyethylene ether sodium sulfate; The hydroxy monomer is one of hydroxyethyl acrylate and hydroxyethyl methacrylate; The carboxyl monomer is one of acrylic acid and methacrylic acid; The soft monomer is one of butyl acrylate and isooctyl acrylate; The hard monomer is one of methyl methacrylate and butyl methacrylate; The chain transfer agent is one of n-octyl mercaptan and n-dodecyl mercaptan; The neutralizing agent is one of ammonia, diethanolamine, triethylamine, and AMP-95; The oxidant is tert-butyl hydrogen peroxide; The reducing agent is one of sodium formaldehyde sulfoxylate, ascorbic acid, and FF6M. The initiator is one of ammonium persulfate, sodium persulfate, and potassium persulfate; The preparation method of the high-permeability hydroxyacrylic acid emulsion includes the following steps: (1) Mix 1 / 3 of the emulsifying functional monomer, 1 / 20 of the hydroxyl monomer, 1 / 20 of the carboxyl monomer, 1 / 149 of the soft monomer, 1 / 30 of the hard monomer and 2 / 3 of the solvent and heat them. Then add 2 / 7 of the initiator to initiate polymerization. After completion, a seed emulsion is obtained. (2) Mix 2 / 3 of the emulsifying functional monomer, 19 / 20 of the hydroxyl monomer, 19 / 20 of the carboxyl monomer, 18 / 149 of the soft monomer, 19 / 30 of the hard monomer, the chain transfer agent and 1 / 6 of the solvent to obtain an emulsion; mix 5 / 7 of the initiator with 1 / 17 of the solvent to obtain an initiator solution. (3) The emulsion and the initiator solution are simultaneously added dropwise to the seed emulsion. After the polymerization reaction is completed, the neutralizing agent is added dropwise to obtain the reaction emulsion. (4) Add 130 / 149 of the soft monomer, 1 / 3 of the hard monomer and the reducing agent dropwise to the reaction emulsion. After polymerization is completed, a high-permeability hydroxy acrylic emulsion is obtained.

2. The method for preparing the high-permeability hydroxyacrylic acid emulsion according to claim 1, characterized in that, The preparation method includes the following steps: (1) Mix 1 / 3 of the emulsifying functional monomer, 1 / 20 of the hydroxyl monomer, 1 / 20 of the carboxyl monomer, 1 / 149 of the soft monomer, 1 / 30 of the hard monomer and 2 / 3 of the solvent and heat them. Then add 2 / 7 of the initiator to initiate polymerization. After completion, a seed emulsion is obtained. (2) Mix 2 / 3 of the emulsifying functional monomer, 19 / 20 of the hydroxyl monomer, 19 / 20 of the carboxyl monomer, 18 / 149 of the soft monomer, 19 / 30 of the hard monomer, the chain transfer agent and 1 / 6 of the solvent to obtain an emulsion; mix 5 / 7 of the initiator with 1 / 17 of the solvent to obtain an initiator solution. (3) The emulsion and the initiator solution are simultaneously added dropwise to the seed emulsion. After the polymerization reaction is completed, the neutralizing agent is added dropwise to obtain the reaction emulsion. (4) Add 130 / 149 of the soft monomer, 1 / 3 of the hard monomer and the reducing agent dropwise to the reaction emulsion. After polymerization is completed, a high-permeability hydroxy acrylic emulsion is obtained.

3. The method for preparing the high-permeability hydroxy acrylic emulsion according to claim 2, characterized in that, In step (1), the heating temperature is 72~75℃; In step (1), the polymerization temperature is 79~81℃ and the polymerization time is 30~40min.

4. The method for preparing the high-permeability hydroxyacrylic acid emulsion according to claim 2, characterized in that, In step (3), the emulsion is added over a period of 60-65 minutes, and the initiator is added over a period of 70-75 minutes. In step (3), the polymerization temperature is 79~81℃.

5. The method for preparing the high-permeability hydroxyacrylic acid emulsion according to claim 2, characterized in that, In step (4), the polymerization temperature is 65~68℃.

6. The application of the high-permeability hydroxy acrylic emulsion of claim 1 as a water-based wood coating.

Images