Chlorinated-epoxy resin obtained by a suspension process

Abstract

This invention relates to the field of chemical synthesis, specifically to a chloroethyl ether resin obtained by suspension polymerization; it is formed by copolymerization of the following monomers: 68-75 parts vinyl chloride; 22-32 parts isobutyl vinyl ether; 0.05-1.0 parts functional monomer A; 0.5-1.0 parts functional monomer B; 0.05-1.0 parts functional monomer C; and the total amount of functional monomers A, B, and C is 0.1-2.0 parts; wherein functional monomer A is selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, and acrylamide; wherein functional monomer B is selected from one or more of ethylene tert-carbonate, trifluoroethyl methacrylate, or fluorinated acrylates; and wherein functional monomer C is selected from one or more of C12-C18 long-chain acrylates. This invention, through research on the structure of functional monomers and suspension polymerization process, classifies functional monomers into three categories and introduces them at different stages of polymerization, enabling each type of monomer to form a synergistic effect in the resin molecular structure.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis, and more specifically to a chlorinated ether resin obtained by suspension method. Background Technology

[0002] Chlorinated ether resins are a type of thermoplastic resin typically produced by copolymerizing vinyl chloride with vinyl ether monomers. Due to their good chemical resistance, film-forming properties, adhesion, and ability to wetting and disperse pigments, they are widely used as binding resins in industrial anti-corrosion coatings, heavy-duty protective coatings, and ink systems, and are especially suitable for protective coatings on metal substrates.

[0003] In existing technologies, the preparation methods of chloroethyl ether resins mainly include two categories: emulsion polymerization and suspension polymerization. Chloroethyl ether resins prepared by the emulsion method have good solubility and pigment development in various organic solvents due to their small polymer particle size and relatively uniform molecular chain distribution, thus finding application in some high-end inks and fine coatings. However, emulsion polymerization typically requires a large amount of emulsifier, and the post-processing involves steps such as demulsification, washing, and dehydration, resulting in a complex process, high water consumption, and high production costs. Furthermore, emulsion-processed chloroethyl ether resins often use water-soluble initiation systems, and the resulting resins still have limited thermal stability under high-temperature conditions and anti-sagging properties under thick-film application conditions.

[0004] In comparison, suspension-processed chloroethylene resins offer advantages such as simpler processing, lower dispersant usage, and lower post-treatment costs, resulting in better anti-sagging properties in coating applications, especially in marine coatings. However, traditional suspension-processed chloroethylene resins typically use vinyl chloride and vinyl ether monomers as the main copolymer system, limiting the content of functional groups in the resin molecule. Consequently, their thermal stability and anti-sagging properties under thick-film application conditions still struggle to simultaneously meet practical application requirements.

[0005] Furthermore, existing modified chloroethyl ether resin technologies primarily focus on formulation adjustments, with less emphasis on altering resin particle growth behavior and monomer characteristics at different reaction stages during suspension polymerization. This fails to fully leverage the impact of polymerization conversion rate variations on resin microstructure formation during suspension polymerization. Therefore, obtaining suspension-polymerized chloroethyl ether resins with good thermal stability and anti-sagging properties through rational formulation adjustments and preparation methods, while maintaining the stability and low-cost advantages of suspension polymerization, remains a pressing technical challenge in this field. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a chloroether resin obtained by suspension polymerization, which, by mass, is formed by copolymerization of the following monomers: Vinyl chloride 68-75 parts; 22-32 parts of isobutyl vinyl ether; Functional monomer A: 0.05–1.0 parts; Functional monomer B: 0.5–1.0 parts; Functional monomer C: 0.05–1.0 parts; Furthermore, the total amount of functional monomers A, B, and C used is 0.1 to 2.0 parts; The functional monomer A is selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, and acrylamide; The functional monomer B is selected from one or more of ethylene tert-carbonate, trifluoroethyl methacrylate, or fluorinated acrylates; The functional monomer C is selected from one or more of C12 to C18 long-chain acrylates.

[0007] Preferably, the amount of functional monomer A is 0.2 to 0.35 parts; the amount of functional monomer B is 0.7 to 0.85 parts.

[0008] Preferably, the functional monomer C is selected from one or more of lauryl methacrylate, hexadecyl acrylate, or octadecyl acrylate.

[0009] The present invention provides a suspension-modified chlorinated ether resin as described in the second aspect, which is suitable for anti-corrosion coatings on metal substrates, especially in the field of marine coatings.

[0010] A third aspect of this invention provides a method for preparing the suspension-modified chloroether resin, employing a staged feeding suspension polymerization process, comprising the following steps: 1) Add the dispersant system, isobutyl vinyl ether, the full amount of functional monomer B, a portion of the buffer and oil-soluble initiator to the aqueous phase to form a stable suspension system; 2) Introduce vinyl chloride and heat to the polymerization temperature to cause vinyl chloride, isobutyl vinyl ether, and functional monomer B to undergo a copolymerization reaction; 3) When the polymerization reaches the intermediate conversion rate, functional monomer A is introduced to participate in the copolymerization of the outer chain segments of the particles; 4) Introduce functional monomer C in the later stage of polymerization to achieve flexible chain segment regulation; 5) Terminate the polymerization and perform degassing, washing, dehydration and drying to obtain the target suspension chloroether resin.

[0011] Preferably, the dispersant system includes anionic dispersant, nonionic dispersant and suspending agent, wherein the mass ratio of anionic dispersant to nonionic dispersant is (1-3):(1).

[0012] Preferably, the polymerization temperature in step 2) is controlled at 60-65°C.

[0013] Preferably, the functional monomer A is added by continuous dripping over a period of 30 to 90 minutes.

[0014] Preferably, the buffer is selected from one or more of sodium sulfite, sodium bisulfite, sodium carbonate, ammonium bicarbonate, ammonia, or sodium hydroxide, and is used to maintain the pH of the polymerization system at 6.0 to 8.5.

[0015] Preferably, the oil-soluble initiator is selected from one or more of azobisisobutyronitrile, azobisisovalerate, benzoyl peroxide, or tert-butyl peroxide-2-ethylhexanoate.

[0016] By adopting the above technical solution, the present invention has the following beneficial effects: This invention, through research on the structure of functional monomers and suspension polymerization processes, classifies functional monomers into three categories and introduces them at different stages of polymerization, enabling each type of monomer to exert a synergistic effect within the resin molecular structure. Specifically, functional monomer B, added in the early stages of polymerization, improves overall thermal stability; functional monomer A, added in the middle stages of polymerization, significantly enhances the interfacial bonding between the resin and the metal substrate; and functional monomer C, added in the later stages of polymerization, improves anti-sagging properties under thick-film application conditions. Through the synergistic effect of the above formulation and process, this invention, while maintaining the simplicity and low cost of suspension polymerization, enables the resulting chloroether resin to possess both excellent thermal stability and anti-sagging properties, overcoming the technical shortcomings of existing technologies where single modification methods cannot simultaneously achieve multiple properties. Detailed Implementation

[0017] This invention provides a chloroether resin obtained by suspension polymerization, which, by mass, is formed by copolymerization of the following monomers: Vinyl chloride 68-75 parts; 22-32 parts of isobutyl vinyl ether; Functional monomer A: 0.05–1.0 parts; Functional monomer B: 0.5–1.0 parts; Functional monomer C: 0.05–1.0 parts; Furthermore, the total amount of functional monomers A, B, and C used is 0.1 to 2.0 parts; The functional monomer A is selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, and acrylamide; The functional monomer B is selected from one or more of ethylene tert-carbonate, trifluoroethyl methacrylate, or fluorinated acrylates; The functional monomer C is selected from one or more of C12 to C18 long-chain acrylates.

[0018] Functional monomer A In this invention, functional monomer A refers to monomer A used in suspension polymerization to introduce polar functional groups into the outer chain segments of resin particles to enhance the interfacial interaction between the resin and the metal substrate.

[0019] Functional monomer A, introduced in the middle and late stages of polymerization, improves the adhesion and interfacial stability of suspension-polymerized chloroether resin on metal substrates without significantly damaging the main structure and thermal stability of the resin.

[0020] Preferably, the functional monomer A is selected from one or more olefin monomers containing carboxyl, hydroxyl, or amide groups, specifically including but not limited to: acrylic acid, methacrylic acid, hydroxyethyl acrylate or hydroxyethyl methacrylate, and acrylamide. Preferably, it is one or a combination of two of the carboxyl-containing acrylic acid or methacrylic acid.

[0021] In a preferred embodiment, the functional monomer A is composed of acrylic acid and methacrylic acid in a mass ratio of (40-60):(40-60), more preferably 1:1, and the total amount of functional monomer A is 0.2-0.35 parts by mass.

[0022] In this invention, functional monomer A is not added at the initial stage of polymerization, but rather introduced during the middle stage of the suspension polymerization reaction when the monomer conversion rate reaches 50-70%. The preferred method of adding functional monomer A is continuous dropwise addition over a period of 30-90 minutes to avoid excessively high local concentrations that could cause particle instability or aggregation. The preferred amount of functional monomer A is 0.2-0.35 parts. This is because when the amount is less than 0.2 parts, the number of polar functional groups is insufficient, making it difficult to form an effective interface; when the amount is greater than 0.35 parts, it can easily lead to increased acidity of the system and excessive polarization of the particle surface, thereby affecting the stability of the suspension system and the thermal stability of the resin.

[0023] Functional monomer B In this invention, functional monomer B refers to a comonomer introduced in the early stage of suspension polymerization and participating in the formation of the internal structure of the chloroether resin molecule.

[0024] Functional monomer B, through the rigid groups or high bond energy structures in its molecular structure, forms a thermally stable structure in the copolymer backbone, thereby improving the glass transition temperature, thermal decomposition stability, dimensional stability and thermal flow resistance of suspension chloroether resin under high temperature conditions.

[0025] Functional monomer B is selected from one or more olefin monomers with special side chain structures, including but not limited to: ethylene tert-carbonate, trifluoroethyl methacrylate, and one or more fluorinated acrylate monomers; preferably ethylene tert-carbonate or a combination thereof with trifluoroethyl methacrylate.

[0026] The amount of functional monomer B is controlled at 0.7~0.85 parts (based on a total monomer content of 100 parts). In a further preferred embodiment: the amount of ethylene tert-carbonate is 0.4~0.6 parts; the amount of trifluoroethyl methacrylate is 0.25~0.35 parts; when the amount of functional monomer B is less than 0.7 parts, the effect on improving thermal stability is not significant; when its amount is more than 0.85 parts, it may lead to excessive stiffening of the resin, affecting flexibility and processing performance.

[0027] In this invention, functional monomer B is added to the reaction system simultaneously with vinyl chloride and isobutyl vinyl ether during the initial stage of suspension polymerization. In the early stages of polymerization, the resin particles have low viscosity and short chain segments, allowing functional monomer B to easily diffuse and uniformly embed within the particles. As polymerization progresses, the particles gradually become denser, and the later-added monomers tend to be distributed on the surface. Therefore, introducing functional monomer B earlier is beneficial for it to function as an internal framework. Through this introduction method, functional monomer B is mainly distributed in the internal main chain structure region of the resin particles, rather than on the surface.

[0028] If functional monomer B is missing, or if it is added in the later stages of polymerization, the resulting chloroether resin is prone to softening, sagging, or dimensional instability under high temperature or thick film application conditions, making it difficult to meet the heat resistance requirements of heavy-duty protective and industrial anti-corrosion coatings.

[0029] Functional monomer C In this invention, functional monomer C refers to a flexible segmental comonomer introduced in the later stages of suspension polymerization to regulate the molecular chain mobility and macroscopic rheological behavior of chloroethyl ether resin. By introducing long-chain flexible side groups into the resin molecular structure, functional monomer C improves the anti-sagging properties and film-forming flexibility of suspension-polymerized chloroethyl ether resin under high-temperature or thick-film application conditions without significantly reducing the resin's thermal stability or increasing the degree of crosslinking.

[0030] The functional monomer C is selected because its molecule contains an unsaturated double bond structure that can participate in free radical copolymerization; its side chain has a long, flexible alkyl structure, which can effectively increase the free volume of the chain segment; it can significantly improve rheological properties under low dosage conditions without compromising the stability of the suspension system. Based on the above principles, the functional monomer C is selected from one or more of C12-C18 long-chain acrylates or methacrylate monomers, more preferably one or more of lauryl methacrylate (C12), hexadecyl acrylate (C16), and octadecyl acrylate (C18); lauryl methacrylate is preferred, or a combination of lauryl methacrylate as the main component and supplemented with C16-C18 long-chain acrylates.

[0031] The amount of functional monomer C is controlled at 0.35 to 0.42 parts (based on a total monomer amount of 100 parts). In a preferred embodiment, functional monomer C is 0.35 to 0.4 parts of lauryl methacrylate and 0 to 0.1 parts of octadecyl acrylate.

[0032] When the amount of functional monomer C is less than 0.35 parts, the improvement effect on anti-sagging and flexibility is not obvious; when its amount is more than 0.42 parts, it may lead to excessive plasticization of the resin, affecting the mechanical strength and heat resistance of the coating film.

[0033] The key structural feature of functional monomer C lies in its long, hydrophobic, flexible alkyl side chains. When introduced into the resin molecule, these chains increase the free volume between chain segments, thereby reducing tight packing and delaying overall chain slippage under high temperature or high shear conditions. The long, flexible side groups of functional monomer C do not significantly lower the glass transition temperature of the main chain; rather, they modulate local chain segment movement behavior, resulting in a smoother rheological response in the resin.

[0034] In this invention, the functional monomer C is introduced in the later stage of suspension polymerization, specifically when the monomer conversion rate reaches 80-90%. This is because the resin particles become denser in the later stages of polymerization, and the newly introduced monomer tends to participate in the growth of the outer layer or end segments of the particles. Due to its hydrophobicity and volume effect, the functional monomer C preferentially distributes on the surface of the particles or in the end-chain region, thus forming a flexible segment regulation layer on the resin particle structure, rather than being uniformly distributed within the main chain. The above preparation method facilitates the preferential rheological regulation of the functional monomer C during application and film formation, while avoiding adverse effects on the overall thermal stability of the resin.

[0035] In this invention, functional monomers A, B, and C are selected through formulation, preparation process settings, and a specific structure of the suspension-modified chloroether resin. Functional monomer B is introduced in the early stages of polymerization and preferentially enters the resin backbone, providing thermal stability to the system. Functional monomer A is introduced in the middle stages of polymerization and enriched on the surface of resin particles, enhancing the interfacial bonding between the resin and the metal substrate through polar functional groups such as carboxyl groups. Functional monomer C is introduced in the later stages of polymerization and mainly distributed at the chain ends or on the outer layer of particles, regulating the mobility of molecular chain segments through flexible long-chain side groups, thereby buffering the rigidity effect brought by the heat-resistant skeleton and polar groups. Through the phased introduction and synergistic effect of these three types of functional monomers, the resulting chloroether resin achieves a balance and improvement in adhesion, thermal stability, and anti-sagging properties in a single system, avoiding the technical defects of performance trade-offs under single modification methods.

[0036] The present invention provides a suspension-type chloroether resin as described in the second aspect that is suitable for anti-corrosion coatings on metal substrates, especially in the field of marine coatings.

[0037] Preparation process The method for preparing the suspension polymerization chloroether resin of this invention employs a staged feeding suspension polymerization process, with a total monomer content of 100 parts by mass and the monomer ratios as follows: Vinyl chloride (VCM): 70 parts; Isobutyl vinyl ether (IBVE): 28.5 parts; Functional monomer A: 0.15 parts acrylic acid (AA) and 0.15 parts methacrylic acid (MAA) (total 0.3 parts); Functional monomer B: 0.5 parts of ethylene tert-carbonate (VEC) and 0.3 parts of trifluoroethyl methacrylate (TFEMA) (total 0.8 parts); Functional monomer C: 0.25 parts lauryl methacrylate (LMA) and 0.15 parts octadecyl acrylate (ODA) (total 0.4 parts); A third aspect of this invention provides a method for preparing the suspension-modified chloroether resin, employing a staged feeding suspension polymerization process, comprising the following steps: Step S1: Add 180 parts of deionized water to a high-pressure polymerization reactor equipped with mechanical stirring, jacket temperature control, and pressure resistance. Start stirring at 25°C, setting the stirring speed to 300 r / min. Add the dispersant system and a portion of the buffer and initiator sequentially, specifically: sodium dodecylbenzenesulfonate: 0.30 parts; fatty alcohol polyoxyethylene ether (AEO-9): 0.20 parts; polyvinyl alcohol (PVA, degree of polymerization approximately 1700): 0.20 parts; sodium hydroxide: 0.25 parts; sodium carbonate: 0.20 parts; azobisisobutyronitrile (AIBN): 0.40 parts.

[0038] Continue stirring for 10 minutes to fully dissolve the dispersant and buffer salt, then add the following to the vessel: 28.5 parts IBVE; 0.5 parts VEC; and 0.3 parts TFEMA.

[0039] After the addition is complete, close the lid, evacuate to -0.09 MPa, purge with nitrogen twice, evacuate to -0.09 MPa again, and pre-stir at 300 r / min for 15 min to form a uniform and stable organic phase droplet suspension system.

[0040] Step S2: Under stirring conditions of 25℃ and 300r / min, continuously introduce 70 parts of VCM into the suspension system obtained in step S1, then turn on the jacket heating to gradually raise the system temperature to 62℃, the pressure inside the reactor to about 0.65~0.7MPa, the stirring speed to 220r / min, and polymerize for 3.5h.

[0041] Step S3: Maintaining the reaction temperature at 62℃ and the stirring speed at 220 r / min, continuously add the entire amount of functional monomer A (0.15 parts acrylic acid and 0.15 parts methacrylic acid) dropwise into the polymerization reactor using a metering pump; the dropping time is controlled at 60 min. During the dropping process, add 0.10 parts sodium carbonate to neutralize some of the free acid, stabilizing the system pH at approximately 7.2. After the dropping is complete, continue the reaction at 62℃ and 220 r / min for 1.5 h.

[0042] Step S4: When the total polymerization time reaches approximately 5.0 h and the monomer conversion rate is approximately 85%, adjust the reaction temperature to 58 °C and maintain a stirring speed of 220 r / min. Add 0.25 parts of functional monomer C:LMA and 0.15 parts of ODA via a metering pump over a period of 45 min. Simultaneously, add 0.15 parts of ammonium bicarbonate to the system to adjust the pH to approximately 7.6. After the addition is complete, continue polymerization at 58 °C and 220 r / min for 1.0 h.

[0043] Step S5: When the pressure inside the reactor drops to approximately 0.25–0.3 MPa, and the basic conversion of the monomer is confirmed by the rate of change in reactor pressure, add 0.10 parts of terminator and antioxidant to the system, and stir for 10 minutes to terminate the polymerization reaction. Then stop heating, cool the system to approximately 45°C, slowly depressurize to atmospheric pressure, and recover unreacted vinyl chloride monomer from the reactor. Reheat to 85°C and maintain for 40 minutes to remove residual vinyl ethers and other low-boiling substances. Then cool to below 35°C, discharge the polymerized resin slurry, and wash twice with deionized water. After each wash, remove the aqueous phase by filtration or centrifugation until the conductivity of the filtrate drops below the process control value. Finally, place the wet resin in a vacuum drying oven at 40–45°C and dry for 12–15 hours to obtain a powdered suspension-processed vinyl chloride ether resin product.

[0044] In this invention, the monomer conversion rate during polymerization is determined by combining reaction time with changes in reactor pressure. After reacting at 62°C for approximately 3.5 hours, the reactor pressure decreases by approximately 35% compared to the initial pressure, indicating that the monomer conversion rate has reached approximately 60%, at which point functional monomer A is introduced. As the reaction continues, the reactor pressure tends to stabilize and decreases only slowly, indicating that the monomer conversion rate has reached approximately 85%, at which point functional monomer C is introduced.

[0045] This invention employs a staged suspension polymerization process, selecting three different monomers to achieve the directional distribution of each monomer within the resin. Therefore, this invention, through the combination of formulation and preparation process, yields different single-monomer suspension-polymerized chloroether resins.

[0046] The present invention will be further explained below with reference to specific embodiments.

[0047] Example 1 The suspension-type chloroether resin provided in this embodiment has a total monomer content of 100 parts by mass, and the monomer ratio is as follows: VCM: 70 copies; IBVE: 28.5 servings; Functional monomer A: AA 0.15 parts, MAA 0.15 parts (total 0.3 parts); Functional monomer B: 0.5 parts VEC, 0.3 parts TFEMA (total 0.8 parts); Functional monomer C: LMA 0.25 parts, ODA 0.15 parts (total 0.4 parts); This embodiment provides a method for preparing the suspension-modified chloroether resin, including the following steps: Step S1: Add 180 parts of deionized water to a high-pressure polymerization reactor equipped with mechanical stirring, jacket temperature control, and pressure resistance. Start stirring at 25°C, setting the stirring speed to 300 r / min. Add the dispersant system and a portion of the buffer and initiator sequentially, specifically: sodium dodecylbenzenesulfonate: 0.30 parts; fatty alcohol polyoxyethylene ether (AEO-9): 0.20 parts; polyvinyl alcohol (PVA, degree of polymerization approximately 1700): 0.20 parts; sodium hydroxide: 0.25 parts; sodium carbonate: 0.20 parts; azobisisobutyronitrile (AIBN): 0.40 parts.

[0048] Continue stirring for 10 minutes to fully dissolve the dispersant and buffer salt, then add the following to the vessel: 28.5 parts IBVE; 0.5 parts VEC; and 0.3 parts TFEMA.

[0049] After the addition is complete, close the lid, evacuate to -0.09 MPa, purge with nitrogen twice, evacuate to -0.09 MPa again, and pre-stir at 300 r / min for 15 min to form a uniform and stable organic phase droplet suspension system.

[0050] Step S2: Under stirring conditions of 25℃ and 300r / min, continuously introduce 70 parts of VCM into the suspension system obtained in step S1, then turn on the jacket heating to gradually raise the system temperature to 62℃, the pressure inside the reactor to about 0.65~0.7MPa, maintain the stirring speed at 220r / min, and polymerize for 3.5h.

[0051] Step S3: Maintaining the reaction temperature at 62℃ and the stirring speed at 220 r / min, continuously add the entire amount of functional monomer A (0.15 parts AA and 0.15 parts MAA) dropwise into the polymerization reactor using a metering pump; the dropping time is controlled at 60 min. During the dropping process, add 0.10 parts sodium carbonate to neutralize some of the free acid, stabilizing the system pH at approximately 7.2. After the dropping is complete, continue the reaction at 62℃ and 220 r / min for 1.5 h.

[0052] Step S4: When the total polymerization time reaches approximately 5.0 h and the monomer conversion rate is approximately 85%, adjust the reaction temperature to 58 °C and maintain a stirring speed of 220 r / min. Add 0.25 parts of functional monomer C:LMA and 0.15 parts of ODA via a metering pump over a period of 45 min. Simultaneously, add 0.15 parts of ammonium bicarbonate to the system to adjust the pH to approximately 7.6. After the addition is complete, continue polymerization at 58 °C and 220 r / min for 1.0 h.

[0053] Step S5: When the pressure inside the reactor drops to approximately 0.25–0.3 MPa, and the basic conversion of the monomer is confirmed by the rate of change in reactor pressure, add 0.10 parts of terminator and antioxidant to the system, and stir for 10 minutes to terminate the polymerization reaction. Then stop heating, cool the system to approximately 45°C, slowly depressurize to atmospheric pressure, and recover unreacted vinyl chloride monomer from the reactor. Reheat to 85°C and maintain for 40 minutes to remove residual vinyl ethers and other low-boiling substances. Then cool to below 35°C, discharge the polymerized resin slurry, and wash twice with deionized water. After each wash, remove the aqueous phase by filtration or centrifugation until the conductivity of the filtrate drops below the process control value. Finally, place the wet resin in a vacuum drying oven at 40–45°C and dry for 12–15 hours to obtain a powdered suspension-processed vinyl chloride ether resin product.

[0054] Example 2 The difference from Example 1 is that the formula has been changed: The monomer ratios of the suspension-type chloroether resin provided in this embodiment are as follows: VCM: 71 copies; IBVE: 27.65 units; Functional monomer A: 0.15 parts AA, 0.15 parts MAA; Functional monomer B: 0.4 parts VEC, 0.25 parts TFEMA; Functional monomer C: LMA 0.4 parts; Comparative Example 1 The difference from Example 1 is that it does not contain functional monomer A, and the remaining components are as follows: VCM: 70 copies IBVE: 28.5 servings Functional monomer B: 0.5 parts VEC, 0.3 parts TFEMA Functional monomer C: 0.25 parts LMA, 0.15 parts ODA Comparative Example 2 The difference from Example 1 is that it does not contain functional monomer B, and the remaining components are as follows: VCM: 70 copies IBVE: 28.5 servings Functional monomer A: 0.15 parts AA, 0.15 parts MAA Functional monomer C: 0.25 parts LMA, 0.15 parts ODA Comparative Example 3 The difference from Example 1 is that it does not contain the functional monomer C, and the remaining components are as follows: VCM: 70 copies IBVE: 28.5 servings Functional monomer A: 0.15 parts AA, 0.15 parts MAA Functional monomer B: 0.5 parts VEC, 0.3 parts TFEMA Comparative Example 4 The difference from Example 1 is that the formulation is the same as in Example 1, but: functional monomer A is added at the beginning, that is, AA and MAA are added at the beginning of polymerization along with VCM.

[0055] Comparative Example 5 The difference from Example 1 is that the formulation is the same as in Example 1, but: functional monomer B is added in the middle stage, that is, VEC and TFEMA are added when the conversion rate is about 60%.

[0056] Comparative Example 6 The difference from Example 1 is that the formulation is the same as in Example 1, but the functional monomers C and B are added at the beginning, that is, LMA and ODA are added at the beginning of polymerization.

[0057] Comparative Example 7 The difference from Example 1 is that functional monomer A uses only acrylic acid, and the formulation is as follows: VCM: 70 copies IBVE: 28.5 servings Functional monomer A: AA 0.3 parts Functional monomer B: 0.5 parts VEC, 0.3 parts TFEMA Functional monomer C: 0.25 parts LMA, 0.15 parts ODA Comparative Example 8 The difference from Example 1 is that the functional monomer C uses only short-chain acrylates, and the formulation is as follows: VCM: 70 copies IBVE: 28.5 servings Functional monomer A: 0.15 parts AA, 0.15 parts MAA Functional monomer B: 0.5 parts VEC, 0.3 parts TFEMA Functional monomer C: Butyl acrylate (BA) 0.4 parts.

[0058] Performance testing: illustrate: Test 1: Tg: Glass transition temperature was determined by differential scanning calorimetry (DSC). Before the test, the resin sample was dried to constant weight under vacuum at 50°C to remove residual moisture and volatile components. Approximately 10 mg of the dried resin sample was weighed and placed in an aluminum crucible, with an empty aluminum crucible used as a reference. During the test, under nitrogen protection, the temperature was increased from 20°C to 120°C at a rate of 20°C / min. The heat flow curve of the sample was recorded, and the midpoint temperature of the heat flow abrupt change range was taken as the glass transition temperature (Tg) of the sample.

[0059] Test 2: T5: Thermogravimetric analysis (TGA) 5% weight loss temperature in nitrogen; The resin sample dried to constant weight was ground into powder, and approximately 10 mg was weighed and placed in a crucible. The temperature was increased from room temperature to 500℃ at a rate of 10℃ / min under a nitrogen atmosphere. The mass change curve of the sample as a function of temperature was recorded, and the temperature corresponding to the initial mass loss of the sample reaching 5% was defined as the 5% weight loss temperature (T5), serving as a characterization index of the resin's thermal stability.

[0060] Test 3: Sagging resistance: Under the same coating formulation conditions, refer to standard GB / T 9264-2012.

[0061] Test 4: Paint film appearance and flexibility: Under the same paint formulation conditions, the paint film appearance and flexibility were tested according to standard GB / T 1731-2020.

[0062] This performance test is only for comparing the differences between suspension chloroether resins obtained by different polymerization methods and does not represent the actual performance of downstream applications.

[0063] Table 1 Performance Test Results

[0064] As shown in Table 1, the suspension-modified chloroether resins obtained in Examples 1 and 2 exhibit excellent and balanced performance in terms of Tg, T5, and anti-sagging properties. Among them, the maximum anti-sagging wet film thickness of Example 1 is significantly higher than that of the comparative examples. When any functional monomer is removed (Comparative Examples 1-3), or the introduction sequence of the corresponding functional monomer is changed (Comparative Examples 4-6), or the structural combination of functional monomers is changed (Comparative Examples 7 and 8), at least one key performance is significantly reduced. This indicates that the present invention achieves a comprehensive improvement in thermal stability and anti-sagging properties in a single resin system through the synergistic effect of functional monomers A / B / C and the synergistic cooperation of the staged feeding suspension polymerization process.

[0065] 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; and these 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 chloroether resin obtained by suspension method, characterized in that, It is formed by copolymerization of the following monomers in parts by weight: Vinyl chloride 68-75 parts; 22-32 parts of isobutyl vinyl ether; Functional monomer A: 0.05–1.0 parts; Functional monomer B: 0.5–1.0 parts; Functional monomer C: 0.05–1.0 parts; Furthermore, the total amount of functional monomers A, B, and C used is 0.1 to 2.0 parts; The functional monomer A is selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, and acrylamide; The functional monomer B is selected from one or more of ethylene tert-carbonate, trifluoroethyl methacrylate, or fluorinated acrylates; The functional monomer C is selected from one or more of C12 to C18 long-chain acrylates.

2. The chloroether resin obtained by suspension method according to claim 1, characterized in that, The amount of functional monomer A is 0.2 to 0.35 parts; the amount of functional monomer B is 0.7 to 0.85 parts.

3. The chloroether resin obtained by suspension method according to claim 1, characterized in that, The functional monomer C is selected from one or more of lauryl methacrylate, hexadecyl acrylate, or octadecyl acrylate.

4. The chloroether resin obtained by suspension method according to any one of claims 1 to 3, characterized in that, The resin is suitable for anti-corrosion coatings on metal substrates, especially in the field of marine coatings.

5. A method for preparing the chloroether resin obtained by suspension method according to any one of claims 1 to 3, characterized in that, The suspension polymerization process employing staged feeding includes the following steps: 1) Add the dispersant system, isobutyl vinyl ether, the full amount of functional monomer B, a portion of the buffer and oil-soluble initiator to the aqueous phase to form a stable suspension system; 2) Introduce vinyl chloride and heat to the polymerization temperature to cause vinyl chloride, isobutyl vinyl ether, and functional monomer B to undergo a copolymerization reaction; 3) When the polymerization reaches the intermediate conversion rate, functional monomer A is introduced to participate in the copolymerization of the outer chain segments of the particles; 4) Introduce functional monomer C in the later stage of polymerization to achieve flexible chain segment regulation; 5) Terminate the polymerization and perform degassing, washing, dehydration and drying to obtain the target suspension chloroether resin.

6. The preparation method according to claim 5, characterized in that, The dispersant system includes anionic dispersants, nonionic dispersants, and suspending agents.

7. The preparation method according to claim 5, characterized in that, In step 2), the polymerization temperature is controlled at 60-65℃.

8. The preparation method according to claim 5, characterized in that, The functional monomer A is added by continuous dripping over a period of 30 to 90 minutes.

9. The preparation method according to claim 5, characterized in that, The buffer is selected from one or more of sodium sulfite, sodium bisulfite, sodium carbonate, ammonium bicarbonate, ammonia, or sodium hydroxide, and is used to maintain the pH of the polymerization system at 6.0 to 8.

5.

10. The preparation method according to claim 5, characterized in that, The oil-soluble initiator is selected from one or more of azobisisobutyronitrile, azobisisovalerate, benzoyl peroxide, or tert-butyl peroxide-2-ethylhexanoate.

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