A polymer emulsion

Abstract

This invention provides a polymer emulsion. The polymer emulsion comprises a cross-linked latex particle core and a hydroxyl-containing shell coating the surface of the cross-linked latex particle core; wherein the glass transition temperature of the cross-linked latex particle core is -60℃ to -30℃, and the glass transition temperature of the hydroxyl-containing shell is 30℃ to 70℃. The polymer emulsion provided by this invention exhibits excellent hardness and good impact resistance.

Description

Technical Field

[0001] This invention relates to the field of polymer emulsions, and more particularly to a polymer emulsion. Background Technology

[0002] Hydroxyl emulsions are widely used in the industrial coatings industry as a basic film-forming substance. Their applications mainly include single-component baking paints formulated with amino resins and two-component paints formulated with isocyanate curing agents. Hydroxyl emulsions possess excellent adhesion, good chemical resistance, and are easy to process, making them an important component in the industrial coatings field.

[0003] Patent document CN111087554 A discloses a high-impact acrylate-styrene-acrylonitrile grafted polymer, its preparation method, and its applications. The acrylate-styrene-acrylonitrile grafted polymer particles have a four-layer structure. The combined effect of a hard internal AS seed layer, a moderately cross-linked core, and a highly cross-linked mantle layer endows the particles with high elasticity. This high elasticity allows the resin to absorb more energy when subjected to external force and to return to its original state after the force disappears, thus giving the resin high impact resistance. The aromatic vinyl compound vinyl cyanide shell grafted outside the mantle layer increases the dispersion performance of the particles in the base resin, which is beneficial for improving impact strength. This technology is used for toughening plastics but is not suitable for the coatings industry.

[0004] However, currently used polymer emulsions cannot achieve a balance between hardness and impact resistance, which greatly limits the application of polymer emulsions. Summary of the Invention

[0005] This invention provides a polymer emulsion that, by defining the structural composition of the polymer emulsion, enables it to achieve both excellent hardness and impact resistance.

[0006] The present invention provides a polymer emulsion comprising a cross-linked latex particle core and a hydroxyl-containing shell covering at least a portion of the surface of the cross-linked latex particle core;

[0007] The glass transition temperature of the hydroxyl-containing shell is 30℃-70℃;

[0008] The core of the cross-linked latex particle is obtained by cross-linking the first component and the cross-linking agent; the glass transition temperature of the first component is -60℃ to -30℃, and the mass percentage of the cross-linking agent accounts for 1wt% to 4wt% of the mass of the core of the cross-linked latex particle; the first component is obtained by polymerization of acrylate compounds and / or vinyl compounds.

[0009] The polymer emulsion described above further includes an intermediate transition layer between the cross-linked latex particle core and the hydroxyl-containing shell; the intermediate transition layer is obtained by polymerization of acrylate compounds and / or vinyl compounds.

[0010] In the polymer emulsion described above, the glass transition temperature of the intermediate transition layer is 70°C-155°C.

[0011] As described above, based on the mass of the polymer emulsion, the mass percentage of the cross-linked latex particle core is 40wt% to 60wt%, the mass percentage of the intermediate transition layer is 0wt% to 40wt%, and the mass percentage of the hydroxyl-containing shell is 10wt% to 45wt%.

[0012] The polymer emulsion described above, wherein the hydroxyl-containing shell is obtained by a third polymerization of acrylate compounds and / or vinyl compounds, hydroxy acrylate monomers, and acid functional monomers.

[0013] In the polymer emulsion described above, during the third polymerization process, the acrylate hydroxy ester monomer accounts for 4 wt%-12 wt% of the total polymer mass, and the acid functional monomer accounts for 0.1 wt%-1 wt% of the total polymer mass.

[0014] In the polymer emulsion described above, the acrylate compound is selected from one or more of methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isooctyl acrylate, isobornyl acrylate, and isobornyl methacrylate.

[0015] And / or, the vinyl monomer is selected from one or more of vinyl acetate, vinyl propionate and vinyl butyrate.

[0016] In the polymer emulsion described above, the crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, ethylene glycol diacrylate, and allyl acrylate.

[0017] In the polymer emulsion described above, the hydroxy acrylate monomer is selected from one or more of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, and 6-hydroxyhexyl acrylate.

[0018] In the polymer emulsion described above, the acid-functionalized monomer is selected from one or more of sulfonic acid monomers, carboxylic acid monomers, phosphonate monomers, phosphate monomers, sulfonate monomers, monoalkyl esters of divalent acids, and monoalkyl esters of divalent anhydrides.

[0019] The polymer emulsion provided by this invention has a core-shell structure, with the cross-linked latex particles forming the core and the hydroxyl-containing shell forming the outer shell, both possessing specific glass transition temperatures. On one hand, the cross-linked structure formed by the first component and the cross-linking agent in the cross-linked latex particles provides high mechanical strength and stability, making the material less prone to deformation or breakage under external forces. Furthermore, the first component, with its relatively low glass transition temperature, maintains a certain degree of flexibility, which helps absorb and disperse impact energy, improving impact resistance. On the other hand, the hydroxyl-containing shell has a relatively high glass transition temperature, resulting in high hardness. The synergistic effect of the shell and core gives the polymer emulsion excellent hardness and impact resistance. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] Polymer emulsions often face a trade-off between hardness and impact resistance in applications. On the one hand, high-hardness polymers typically have higher crystallinity and stronger intermolecular forces, making the material harder. However, this rigid structure often leads to brittleness, reducing the impact resistance of the polymer emulsion. On the other hand, impact resistance usually requires the polymer to have a certain degree of flexibility and ductility, which can be achieved by increasing the flexibility of the polymer chains or introducing plasticizers. However, this flexible structure reduces the hardness of the polymer emulsion.

[0022] To simultaneously improve hardness and impact resistance, it is necessary to explore the structural composition of polymer emulsions.

[0023] The present invention provides a polymer emulsion comprising a cross-linked latex particle core and a hydroxyl-containing shell covering at least a portion of the surface of the cross-linked latex particle core;

[0024] The glass transition temperature of the hydroxyl-containing shell is 30℃-70℃;

[0025] The core of the cross-linked latex particle is obtained by cross-linking the first component and the cross-linking agent; the glass transition temperature of the first component is -60℃ to -30℃, and the mass percentage of the cross-linking agent accounts for 1wt% to 4wt% of the mass of the core of the cross-linked latex particle; the first component is obtained by polymerization of acrylate compounds and / or vinyl compounds.

[0026] The polymer emulsion provided by the present invention has a core-shell structure, consisting of a cross-linked latex particle core and a hydroxyl-containing shell.

[0027] In detail, the first component is obtained by polymerizing acrylate compounds and / or vinyl compounds. These compounds are commonly used to prepare polymers with good flexibility and transparency. Acrylate compounds provide good weather resistance and optical properties, while vinyl compounds can be used to adjust the mechanical properties of the polymer by selecting different monomers.

[0028] The glass transition temperature (Tg) of the first component of this invention includes, but is not limited to, a range of -60°C, -55°C, -50°C, -45°C, -40°C, -35°C, -30°C, or any combination thereof. The lower glass transition temperature gives the first component excellent flexibility and ductility, enabling it to effectively absorb and disperse impact energy.

[0029] When the first component is cross-linked with a certain mass content of cross-linking agent, a cross-linked structure is formed between the first component and the cross-linking agent, which improves the structural integrity of the core of the cross-linked latex particles, so that the core of the cross-linked latex particles maintains a certain shape and size stability.

[0030] The mass percentage of the crosslinking agent includes, but is not limited to, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, or any combination thereof.

[0031] The hydroxyl groups in the hydroxyl-containing shell can increase the polarity of the polymer emulsion, thereby improving the compatibility and adhesion of the polymer emulsion with other materials during use. The glass transition temperature of the hydroxyl-containing shell includes, but is not limited to, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, or any combination thereof.

[0032] The polymer emulsion provided by this invention exhibits excellent hardness and good impact resistance. On one hand, the cross-linked structure formed by the first component and the cross-linking agent in the cross-linked latex particles provides rubber-like mechanical strength and impact resistance, making the material less prone to damage under external forces, thus helping to absorb and disperse impact energy and improve impact resistance. On the other hand, the hydroxyl-containing outer shell is reactive, and after reacting with the curing agent, it acquires high hardness. The synergistic effect of the outer shell and the core results in the polymer emulsion possessing excellent hardness and impact resistance.

[0033] The glass transition temperature range of the hydroxyl-containing shell can be adjusted according to the matching curing agent. In one specific embodiment, the polymer emulsion is used in combination with an amino resin curing agent, and the glass transition temperature of the hydroxyl-containing shell is 30°C-50°C. In another specific embodiment, the polymer emulsion is used in combination with an isocyanate curing agent, and the glass transition temperature of the hydroxyl-containing shell is 40°C-70°C.

[0034] In one specific embodiment, an intermediate transition layer is further included between the core of the cross-linked latex particle and the hydroxyl-containing shell; the intermediate transition layer is obtained by polymerization of acrylate compounds and / or vinyl compounds.

[0035] In one specific embodiment, the glass transition temperature of the intermediate transition layer is 70°C-155°C.

[0036] In detail, the glass transition temperature of the intermediate transition layer includes, but is not limited to, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 155°C, or any combination thereof.

[0037] The cross-linked latex particle core and the hydroxyl-containing shell have a large polarity difference. The presence of the intermediate transition layer can not only improve the compatibility between the cross-linked latex particle core and the hydroxyl-containing shell, ensuring the overall uniformity and preparation stability of the material, but also provide more stable high hardness performance and optimize the overall performance of the polymer emulsion.

[0038] For polymer emulsions, the mass percentage of each component directly affects hardness and impact resistance. In one specific embodiment, based on the mass of the polymer emulsion, the mass percentage of the cross-linked latex particle core is 40wt%–60wt%, the mass percentage of the intermediate transition layer is 0wt%–40wt%, and the mass percentage of the hydroxyl-containing shell is 10wt%–40wt%.

[0039] In detail, the mass percentage of the cross-linked latex particle core includes, but is not limited to, 40 wt%, 42 wt%, 44 wt%, 46 wt%, 48 wt%, 50 wt%, 52 wt%, 54 wt%, 56 wt%, 58 wt%, 60 wt%, or any combination thereof.

[0040] The mass content of the intermediate transition layer includes, but is not limited to, 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, or any combination thereof, preferably, the mass content of the intermediate transition layer is 20 wt%-30 wt%.

[0041] The mass content of the hydroxyl-containing shell includes, but is not limited to, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, or any combination thereof, preferably, the mass content of the hydroxyl-containing shell is 20 wt%-30 wt%.

[0042] When the mass percentage of each component of the polymer emulsion is within the above range, it can effectively balance the impact resistance of the cross-linked latex particles and the hardness of the hydroxyl-containing shell, so that the polymer emulsion can take into account both impact resistance and hardness.

[0043] In one specific embodiment, the hydroxyl-containing shell is obtained by a third polymerization of acrylate compounds and / or vinyl compounds, hydroxyl acrylate monomers, and acid functional monomers.

[0044] Acrylates and / or vinyl compounds offer good mechanical properties and weather resistance. Hydroxyl acrylate monomers can introduce hydroxyl groups, which ensure the polymer's reactivity. Acid-functionalized monomers can improve emulsion stability.

[0045] In one specific embodiment, the hydroxy acrylate monomer accounts for 4 wt%-12 wt% of the total polymer and the acid functional monomer accounts for 0.1 wt%-1 wt% of the total polymer.

[0046] Through this specific combination and mass ratio of monomers, polymer emulsions can provide excellent performance in a variety of applications, including coatings, adhesives, and sealants. This design not only improves the functionality of the material but also enhances its reliability and durability in practical applications.

[0047] In one specific embodiment, the acrylate compound is selected from one or more of methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isooctyl acrylate, isobornyl acrylate, and isobornyl methacrylate.

[0048] In one specific embodiment, the crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, ethylene glycol diacrylate, and allyl acrylate.

[0049] When the crosslinking agent is selected from the above types, on the one hand, the crosslinking agent can better crosslink with the first component to form a three-dimensional network structure, thereby improving the impact resistance of the polymer.

[0050] In one specific embodiment, the hydroxy acrylate monomer is selected from one or more of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, and 6-hydroxyhexyl acrylate.

[0051] Preferably, the hydroxy acrylate monomer is selected from one or more of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl acrylate.

[0052] In another specific embodiment, the acid functional monomer is selected from one or more of sulfonic acid monomers, carboxylic acid monomers, phosphonate monomers, phosphate monomers, sulfonate monomers, monoalkyl esters of divalent acids, and monoalkyl esters of divalent anhydrides.

[0053] Preferably, the acid-functionalized monomer is selected from carboxylic acid monomers, such as acrylic acid and methacrylic acid.

[0054] The present invention will be further described below through specific embodiments.

[0055] Example 1

[0056] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0057] Component A: Mix 80g of water, 1.5g of sodium dodecyl sulfonate (SDS), 221g of butyl acrylate (BA), and 9g of ethylene glycol dimethacrylate (EGDMA) to form a pre-emulsion (Tg: -54℃, accounting for 58% of the total content; crosslinking agent accounts for 4% of the total mass of BA, MMA, and EGDMA in Component A).

[0058] Component B: Mix 40g of water, 0.5g of SDS, and 90g of methyl methacrylate (MMA) to form a pre-emulsion (Tg is 105℃, accounting for 22%).

[0059] Component C: Mix 40g water, 1g emulsifier 710, 0.5g SDS, 37g MMA, 23g BA, 19g 2-hydroxyethyl methacrylate (HEMA), and 1g acrylic acid (AA) to form a pre-emulsion (Tg is 30℃, accounting for 20%).

[0060] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer, and heat to 85℃. Add 20g of component A, 0.5g of sodium polydisulfide dipropane sulfonate (SPS), and 5g of water to the flask. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise simultaneously. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0061] Example 2

[0062] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0063] Component A: Mix 80g water, 1.5g SDS, 221g BA, and 9g EGDMA to form a pre-emulsion (Tg: -54℃, accounting for 58% of the total; crosslinking agent accounts for 4% of the total mass of BA, MMA, and EGDMA in Component A).

[0064] Component B: Mix 40g of water, 0.5g of SDS, and 90g of MMA to form a pre-emulsion (Tg is 105℃, accounting for 22%).

[0065] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 45g of MMA, 15g of BA, 19g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 50℃, accounting for 20%).

[0066] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0067] Example 3

[0068] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0069] Component A: Mix 80g water, 1.5g SDS, 27.7g BA, and 2.3g EGDMA to form a pre-emulsion (Tg: -54℃, accounting for 58% of the total; crosslinking agent accounts for 1% of the total mass of BA, MMA, and EGDMA in Component A).

[0070] Component B: Mix 40g of water, 0.5g of SDS, and 90g of MMA to form a pre-emulsion (Tg is 105℃, accounting for 22%).

[0071] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 37g of MMA, 23g of BA, 19g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 30℃, accounting for 20%).

[0072] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0073] Example 4

[0074] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0075] Component A: Mix 80g water, 1.5g SDS, 121g BA, 37.4g MMA, and 1.6g EGDMA to form a pre-emulsion (Tg: -30℃, accounting for 40% of the total; crosslinking agent accounts for 1% of the total mass of BA, MMA, and EGDMA in Component A).

[0076] Component B: Mix 40g of water, 0.5g of SDS, and 120g of MMA to form a pre-emulsion (Tg105, 30%).

[0077] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 88g of MMA, 12g of BA, 19g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 50℃, accounting for 30%).

[0078] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0079] Example 5

[0080] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0081] Component A: Mix 80g water, 1.5g SDS, 120g BA, 38.4g MMA, and 1.6g EGDMA to form a pre-emulsion (Tg: -30℃, accounting for 40% of the total; crosslinking agent accounts for 1% of the total mass of BA, MMA, and EGDMA in Component A).

[0082] Component B: Mix 40g of water, 0.5g of SDS, and 120g of MMA to form a pre-emulsion (Tg is 105℃, accounting for 30%).

[0083] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 71g of MMA, 9g of BA, 39g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 70℃, accounting for 30%).

[0084] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0085] Example 6

[0086] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0087] Component A: Mix 80g water, 1.5g SDS, 170g BA, 26g MMA, and 4g EGDMA to form a pre-emulsion (Tg: -50℃, 50% of the total content; crosslinking agent accounts for 2% of the total mass of BA, MMA, and EGDMA in Component A).

[0088] Component B: Mix 40g of water, 0.5g of SDS, 70g of MMA, and 10g of BA to form a pre-emulsion (Tg is 73℃, accounting for 20%).

[0089] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 71g of MMA, 9g of BA, 39g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 70℃, accounting for 30%).

[0090] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0091] Example 7

[0092] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0093] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0094] Component A: Mix 80g of water, 1.5g of sodium dodecyl sulfonate (SDS), 221g of butyl acrylate (BA), and 9g of ethylene glycol dimethacrylate (EGDMA) to form a pre-emulsion (Tg: -54℃, accounting for 58% of the total content; crosslinking agent accounts for 4% of the total mass of BA, MMA, and EGDMA in Component A).

[0095] Component B: This component was not added.

[0096] Component C: Mix 80g of water, 1g of emulsifier 710, 1g of SDS, 96g of MMA, 54g of BA, 19g of 2-hydroxyethyl methacrylate (HEMA), and 1g of acrylic acid (AA) to form a pre-emulsion (Tg is 30℃, accounting for 42%).

[0097] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer, and heat to 85°C with stirring. Add 20g of component A, 0.5g of sodium polydisulfide dipropane sulfonate (SPS), and 5g of water to the vessel. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise simultaneously. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2°C for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component C, 0.3g of SPS, and 20g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2°C for 1 hour. Cool to below 50°C, adjust the pH to 7-8 with ammonia, and discharge to obtain a polymer emulsion without an intermediate transition layer.

[0098] Comparative Example 1

[0099] The method for preparing the polymer emulsion provided in this comparative example includes the following steps:

[0100] Component A: Mix 80g of water, 1.5g of SDS, and 230g of BA to form a pre-emulsion (Tg: -54℃, 58% content, excluding crosslinking agent).

[0101] Component B: Mix 40g of water, 0.5g of SDS, and 90g of MMA to form a pre-emulsion (Tg is 105℃, accounting for 22%).

[0102] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 37g of MMA, 23g of BA, 19g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 30℃, accounting for 20%).

[0103] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0104] Comparative Example 2

[0105] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0106] Component A: Mix 80g of water, 1.5g of SDS, and 230g of BA to form a pre-emulsion (Tg: -54℃, 58% content, excluding crosslinking agent).

[0107] Component B: Mix 40g of water, 0.5g of SDS, and 90g of MMA to form a pre-emulsion (Tg is 105℃, accounting for 22%).

[0108] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 45g of MMA, 15g of BA, 19g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 50℃, accounting for 20%).

[0109] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0110] Comparative Example 3

[0111] The method for preparing the polymer emulsion provided in this comparative example includes the following steps:

[0112] Component A: Mix 80g of water, 1.5g of SDS, 121g of BA, and 39g of MMA to form a pre-emulsion (Tg: -30℃, 40% of the total, excluding crosslinking agent).

[0113] Component B: Mix 40g of water, 0.5g of SDS, and 120g of MMA to form a pre-emulsion (Tg is 105℃, accounting for 30%).

[0114] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 88g of MMA, 12g of BA, 19g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 50℃, accounting for 30%).

[0115] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0116] Comparative Example 4

[0117] The method for preparing the polymer emulsion provided in this comparative example includes the following steps:

[0118] Component A: Mix 80g of water, 1.5g of SDS, 173g of BA, and 27g of MMA to form a pre-emulsion (Tg: -50℃, 50% of the total, excluding crosslinking agent).

[0119] Component B: Mix 40g of water, 0.5g of SDS, 70g of MMA, and 10g of BA to form a pre-emulsion (Tg is 73℃, accounting for 20%).

[0120] Component C: Mix 40g of water, 1g of emulsifier 710, 0.5g of SDS, 71g of MMA, 9g of BA, 39g of HEMA, and 1g of AA to form a pre-emulsion (Tg is 70℃, accounting for 30%).

[0121] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer. Stir and heat to 85℃. Add 20g of component A, along with 0.5g of SPS and 5g of water. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0122] Comparative Example 5

[0123] The method for preparing the polymer emulsion provided in this comparative example includes the following steps:

[0124] The method for preparing the polymer emulsion provided in this embodiment includes the following steps:

[0125] Component A: Mix 80g of water, 1.5g of sodium dodecyl sulfonate (SDS), 150g of butyl acrylate (BA), 71g of MMA, and 9g of ethylene glycol dimethacrylate (EGDMA) to form a pre-emulsion (Tg is -20℃, accounting for 58%, and the crosslinking agent accounts for 4% of the total mass of BA, MMA, and EGDMA in Component A).

[0126] Component B: Mix 40g of water, 0.5g of SDS, and 90g of methyl methacrylate (MMA) to form a pre-emulsion (Tg is 105℃, accounting for 22%).

[0127] Component C: Mix 40g water, 1g emulsifier 710, 0.5g SDS, 37g MMA, 23g BA, 19g 2-hydroxyethyl methacrylate (HEMA), and 1g acrylic acid (AA) to form a pre-emulsion (Tg is 30℃, accounting for 20%).

[0128] Add 400g of water and 0.5g of emulsifier SDS to a four-necked flask equipped with an ice tube, dropping device, stirrer, and thermometer, and heat to 85℃. Add 20g of component A, 0.5g of sodium polydisulfide dipropane sulfonate (SPS), and 5g of water to the flask. Wait 15-30 minutes, then begin to add the remaining component A, 0.5g of SPS, and 20g of water dropwise simultaneously. The dropping time is 2-3 hours. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain the core of the cross-linked latex particles. Continue to add component B, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 30 minutes to obtain an intermediate with an intermediate transition layer. Continue to add component C, 0.3g of SPS, and 10g of water dropwise for 1 hour. After the dropping is completed, maintain the temperature at 85±2℃ for 1 hour. The temperature was lowered to below 50°C, and the pH was adjusted to 7-8 with ammonia water. The product was then discharged to obtain a polymer emulsion with a hydroxyl-containing outer shell.

[0129] Test case

[0130] The hardness and impact resistance of the polymer emulsions provided in the examples and comparative examples were tested using amino resin curing agents and isocyanate curing agents, respectively.

[0131] The formulations using polymer emulsion and amino resin curing agent are shown in Table 1, and the formulations using polymer emulsion and isocyanate curing agent are shown in Table 2. The test samples in Tables 1 and 2 refer to the polymer emulsions provided in different embodiments.

[0132] Table 1

[0133]

[0134] Table 2

[0135]

[0136]

[0137] The testing methods, instruments, and standards are shown in Table 3.

[0138] Table 3

[0139]

[0140]

[0141] Suitable curing agents were selected based on the principle of preference for performance testing. The test results of using amino curing agents in Examples 1, 2, 3, 4, 7 and Comparative Examples 1, 2, 3, 5 are shown in Table 4, while the test results of using isocyanate curing agents in Examples 2, 4, 5, 6 and Comparative Examples 2, 3, 4 are shown in Table 5.

[0142] Table 4

[0143]

[0144] Table 5

[0145]

[0146] As shown in Tables 4 and 5, the polymer emulsion provided by the present invention has high hardness and excellent impact resistance after reacting with the curing agent.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polymer emulsion, characterized in that, It includes a cross-linked latex particle core and a hydroxyl-containing shell covering at least a portion of the surface of the cross-linked latex particle core; The glass transition temperature of the hydroxyl-containing shell is 30℃-70℃; The core of the cross-linked latex particle is obtained by cross-linking the first component and the cross-linking agent; the glass transition temperature of the first component is -60℃ to -30℃, and the mass percentage of the cross-linking agent accounts for 1wt% to 4wt% of the mass of the core of the cross-linked latex particle; the first component is obtained by polymerization of acrylate compounds and / or vinyl compounds.

2. The polymer emulsion according to claim 1, characterized in that, The cross-linked latex particle core and the hydroxyl-containing shell further include an intermediate transition layer; the intermediate transition layer is obtained by polymerization of acrylate compounds and / or vinyl compounds.

3. The polymer emulsion according to claim 2, characterized in that, The glass transition temperature of the intermediate transition layer is 70℃-155℃.

4. The polymer emulsion according to claim 2, characterized in that, Based on the mass of the polymer emulsion, the mass percentage of the cross-linked latex particle core is 40wt% to 60wt%, the mass percentage of the intermediate transition layer is 0wt% to 40wt%, and the mass percentage of the hydroxyl-containing shell is 10wt% to 45wt%.

5. The polymer emulsion according to claim 2, characterized in that, The hydroxyl-containing shell is obtained by a third polymerization of acrylate compounds and / or vinyl compounds, hydroxy acrylate monomers, and acid functional monomers.

6. The polymer emulsion according to claim 5, characterized in that, In the third polymerization process, the hydroxy acrylate monomer accounts for 4 wt%-12 wt% of the total polymer and the acid functional monomer accounts for 0.1 wt%-1 wt% of the total polymer.

7. The polymer emulsion according to claim 5, characterized in that, The acrylate compounds are selected from one or more of methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isooctyl acrylate, isobornyl acrylate, and isobornyl methacrylate. And / or, the vinyl monomer is selected from one or more of vinyl acetate, vinyl propionate and vinyl butyrate.

8. The polymer emulsion according to claim 1, characterized in that, The crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, ethylene glycol diacrylate, and allyl acrylate.

9. The polymer emulsion according to claim 6, characterized in that, The hydroxy acrylate monomer is selected from one or more of the following: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, and 6-hydroxyhexyl acrylate.

10. The polymer emulsion according to claim 6, characterized in that, The acid functional monomer is selected from one or more of sulfonic acid monomers, carboxylic acid monomers, phosphonate monomers, phosphate monomers, sulfonate monomers, monoalkyl esters of divalent acids, and monoalkyl esters of divalent anhydrides.

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