Preparation method of modified calcium-zinc stabilizer for SPC

Abstract

The invention discloses a preparation method of a modified calcium-zinc stabilizer for SPC, and relates to the technical field of stabilizer preparation. Comprising the following steps: synthesizing a CaSt2-coated CeSt3 compound, preparing stearic acid modified magnesium-aluminum hydrotalcite, and preparing the modified calcium-zinc stabilizer. Synthesizing a CaSt2-coated CeSt3 compound: preparing the CaSt2-coated CeSt3 compound from a calcium stearate suspension, a Ce (NO3) 3 solution and a sodium stearate solution; preparing stearic acid modified magnesium-aluminum hydrotalcite: preparing the stearic acid modified magnesium-aluminum hydrotalcite from stearic acid and magnesium-aluminum hydrotalcite; the modified calcium-zinc stabilizer is prepared from the following raw materials: stearic acid, nano-zinc oxide, a CaSt2 (at) CeSt3 compound, stearic acid modified magnesium-aluminum hydrotalcite, monoglyceride, polyethylene wax, pentaerythritol, light calcium carbonate, a mildew preventive and an anti-ultraviolet absorbent. The prepared modified calcium-zinc stabilizer has excellent thermal stability, and can effectively enhance the mechanical properties and aging resistance of SPC.

Description

Technical Field

[0001] The present invention relates to the technical field of stabilizer preparation, and in particular to a method for preparing a modified calcium zinc stabilizer for SPC. Background Art

[0002] Stone-plastic composite (SPC) is a new environmentally friendly flooring material made from polyvinyl chloride (PVC) as a base material supplemented with inorganic fillers such as calcium powder through extrusion and calendering processes. Due to its wear resistance, water resistance, and formaldehyde-free properties, it is widely used in home and commercial floor decoration. SPC processing requires high temperatures of 180-200°C, which can easily remove unstable chlorine atoms from the PVC molecular chain and cause degradation. Therefore, a heat stabilizer is added to inhibit this process. Calcium-zinc stabilizers are the mainstream choice because they are free of heavy metals such as lead and cadmium, meeting environmental requirements.

[0003] Calcium zinc stabilizers usually take calcium stearate and zinc stearate as the core, and are compounded with lubricants, auxiliary stabilizers, etc., and work by capturing HCl produced by degradation and replacing unstable chlorine atoms. However, the existing technology has obvious limitations: zinc ions easily catalyze the degradation of polyvinyl chloride at high temperatures; auxiliary stabilizers are difficult to disperse evenly and cannot effectively enhance mechanical properties; and the anti-aging system lacks synergy with the thermal stabilization system. The existing technology with publication number CN118599188A discloses a transparent calcium zinc stabilizer, its preparation method, and its application in PVC. This existing technology mainly relies on the synergy of zinc stearate, calcium stearate and modified silica. It is difficult to cope with the long-term high temperature environment of 180-200°C in SPC processing, has poor thermal stability, and has limited enhancement of mechanical properties. It has not formed a synergistic system of thermal stability and anti-ultraviolet. The prior art with publication number CN119241911A discloses an environmentally friendly calcium-zinc composite thermal stabilizer and a preparation method thereof. This prior art mainly relies on the synergistic effect of β-diketone, modified organic acid intercalated hydrotalcite, and modified silica, resulting in low thermal stabilization efficiency and limited improvement in the mechanical properties of SPC.

[0004] In summary, although the existing technical solutions have improved certain properties of calcium zinc stabilizers to a certain extent, the following technical problems still exist: poor thermal stability and inability to effectively enhance the mechanical properties and anti-aging properties of SPC. Summary of the Invention

[0005] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a method for preparing a modified calcium-zinc stabilizer for SPC, and achieves the following invention objectives: preparing a calcium-zinc stabilizer with high thermal stability, while effectively enhancing the mechanical properties and anti-aging properties of SPC.

[0006] To achieve the above objectives, the technical solutions adopted are as follows: A method for preparing a modified calcium zinc stabilizer for SPC, comprising the steps of synthesizing a CaSt2@CeSt3 complex, preparing stearic acid-modified magnesium aluminum hydrotalcite, and obtaining the modified calcium zinc stabilizer; The synthesis of CaSt2@CeSt3 complex: the CaSt2@CeSt3 complex is prepared from a calcium stearate suspension, a Ce(NO3)3 solution, and a sodium stearate solution; The preparation of stearic acid-modified magnesium aluminum hydrotalcite comprises modifying magnesium aluminum hydrotalcite with stearic acid to obtain stearic acid-modified magnesium aluminum hydrotalcite; The prepared modified calcium zinc stabilizer adopts raw materials including: stearic acid, nano zinc oxide, CaSt2@CeSt3 composite, stearic acid modified magnesium aluminum hydrotalcite, monoglyceride, polyethylene wax, pentaerythritol, light calcium carbonate, mildew inhibitor, anti-ultraviolet absorber; The anti-ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole; the mildew inhibitor is 1,2-benzisothiazolin-3-one; the monoglyceride is molecular distilled monoglyceride; and the particle size of the nano zinc oxide is 50-100 nm.

[0007] The raw materials used to prepare the modified calcium zinc stabilizer are as follows: 60-80 parts by weight of stearic acid, 5-8 parts of nano zinc oxide, 2-5 parts of CaSt2@CeSt3 complex, 2-4 parts of stearic acid-modified magnesium aluminum hydrotalcite, 5-10 parts of monoglyceride, 5-10 parts of polyethylene wax, 2-5 parts of pentaerythritol, 5-10 parts of light calcium carbonate, 1-2 parts of mildew inhibitor, and 2-3 parts of anti-ultraviolet absorber.

[0008] Furthermore, the synthesis of the CaSt2@CeSt3 complex: Calcium stearate is dispersed in deionized water at 60-65° C., with a solid-liquid ratio of calcium stearate to deionized water of 1:10. Ultrasonic treatment is performed at a power of 300-400 W for 10-15 minutes to obtain a calcium stearate suspension.

[0009] The calcium stearate suspension was heated to 70-80°C, stirred at 800-900 rpm, and Ce(NO3)3 solution was slowly added dropwise, with the molar ratio of Ce(NO3)3 to calcium stearate being (2-3):10 and the dropwise acceleration rate being 2-3 mL / min. After the dropwise addition was completed, the stirring reaction was continued for 10-15 minutes. Then, sodium stearate solution was slowly added dropwise, with the molar ratio of sodium stearate to Ce(NO3)3 being (3-3.5:1) and the dropwise acceleration rate being 3-5 mL / min. During the dropwise addition process, the pH value was adjusted to 8-9 with NaOH. After the dropwise addition was completed, the stirring reaction was continued for 1-1.5 hours. After the reaction was completed, filtration was performed to obtain a CaSt2@CeSt3 complex precipitate. The CaSt2@CeSt3 complex is then precipitated and washed with deionized water at 80-85°C until neutral; after washing, it is dried at 60-80°C for 12-14 hours; after drying, it is crushed and then passed through a 200-mesh sieve to obtain a CaSt2@CeSt3 complex. The calcium stearate has a purity of ≥98% and a particle size of 1-5μm; the Ce(NO3)3 solution is prepared by dissolving Ce(NO3)3·6H2O in deionized water at a concentration of 0.5mol / L; the sodium stearate solution is prepared by dissolving sodium stearate in deionized water at 80-90°C at a concentration of 1mol / L; and the concentration of the NaOH solution is 1mol / L.

[0010] Furthermore, the preparation of stearic acid modified magnesium aluminum hydrotalcite: Stearic acid is heated to 70-80°C to obtain molten stearic acid; dried magnesium aluminum hydrotalcite is added to a high-speed mixer, heated to 80-90°C, stirred at 800-1000 rpm; the molten stearic acid is slowly dripped into the mixer at a rate of 5-10 mL / min to a concentration of 1-3% of the mass of the magnesium aluminum hydrotalcite; the stirring is continued for 30-60 minutes after the dripping is completed; the mixture is then crushed in a grinder and passed through a 200 mesh sieve to obtain stearic acid-modified magnesium aluminum hydrotalcite. The magnesium aluminum hydrotalcite has a Mg / Al molar ratio of 3:1 and a particle size of 300-500 nm.

[0011] Furthermore, the prepared modified calcium zinc stabilizer: Heat monoglyceride to 60-70°C to melt, add polyethylene wax, heat to 110-120°C to melt, stir and mix, then cool to 80-90°C, add pentaerythritol, light calcium carbonate and nano zinc oxide, and stir at 800-1000 rpm for 15-20 minutes to obtain mixture A. The reactor is heated to 70-75°C, preheated for 20-40 minutes, and stirred at a rate of 300-500 rpm. Stearic acid is added, stirred and melted, and the temperature is raised to 115-120°C. Mixture A is then added, the stirring rate is increased to 600-800 rpm, and the mixture is stirred for 20-40 minutes. Then, the temperature is raised to 120-130°C, and a CaSt2@CeSt3 complex and a stearic acid-modified magnesium aluminum hydrotalcite are successively added, the stirring rate is increased to 800-1000 rpm, and the mixture is stirred and reacted for 20-40 minutes. Then, a mildew inhibitor and an anti-ultraviolet absorber are added, the stirring rate is reduced to 600-800 rpm, and the mixture is stirred for 10-20 minutes. After standing, the material is discharged and passed through a double-roll cooling tablet press to obtain a modified calcium zinc stabilizer.

[0012] The present invention uses a step-by-step dropwise reaction to directionally deposit CeSt3 on the surface of CaSt2 particles, forming a core-shell structure of "CaSt2 as the core and CeSt3 as the shell", and CeSt3 is evenly coated on the surface of CaSt2 in the form of a nanolayer. In the prior art, CaSt2 and CeSt3 particles are physically mixed, and there is no strong interaction between the particles. They are prone to agglomeration or stratification due to differences in density and surface energy, and the components are unevenly distributed. The effect of the calcium zinc stabilizer depends on its uniform distribution in the matrix; the uneven distribution of components in the prior art will form a local "stable weak zone", causing SPC to preferentially degrade in this weak zone. In addition, the CaSt2@CeSt3 complex is a core-shell structure, and the CeSt3 in the shell layer blocks HCl and free radicals, preventing CaSt2 from premature oxidation; in the early stage of high-temperature processing, CeSt3 is consumed and exerts its effect from the outside to the inside, and CeSt3 gradually participates in the reaction as the processing progresses, achieving "continuous stability" and extending the effective life of the stabilizer.

[0013] The beneficial effects of the present invention are as follows: (1) A modified calcium zinc stabilizer for SPC prepared by the present invention has excellent thermal stability. After heating for 24 hours, the weight loss rate of the modified calcium zinc stabilizer prepared by the present invention is 1.01-1.35%.

[0014] (2) The modified calcium-zinc stabilizer for SPC prepared by the present invention can effectively improve the mechanical properties of SPC. The SPC samples prepared using the modified calcium-zinc stabilizer prepared by the present invention as raw material have a tensile strength of 53.3-56.5 MPa and an elongation at break of 76.9-81.7%.

[0015] (3) The modified calcium zinc stabilizer for SPC prepared by the present invention can effectively enhance the anti-aging properties of SPC. After heat aging and UV aging, the SPC samples prepared using the modified calcium zinc stabilizer prepared by the present invention as raw material showed a Congo red test paper color change time of 89-96 minutes and a tensile strength retention rate of 92.8-94.5%. DETAILED DESCRIPTION

[0016] To make the purpose, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0017] Example 1 Preparation method of modified calcium zinc stabilizer for SPC A method for preparing a modified calcium zinc stabilizer for SPC comprises the following steps: Step 1: Synthesis of CaSt2@CeSt3 complex Calcium stearate was dispersed in deionized water at 60° C., with a solid-liquid ratio of calcium stearate to deionized water of 1:10, and ultrasonic treatment was performed at a power of 300 W for 15 minutes to obtain a calcium stearate suspension.

[0018] The calcium stearate suspension was heated to 70°C, stirred at 800 rpm, and Ce(NO3)3 solution was slowly added dropwise, with a molar ratio of Ce(NO3)3 to calcium stearate of 2:10 and a dropping rate of 2 mL / min. After the addition was completed, the stirring reaction was continued for 15 minutes; then sodium stearate solution was slowly added dropwise, with a molar ratio of sodium stearate to Ce(NO3)3 of 3:1 and a dropping rate of 3 mL / min. During the addition process, the pH value was adjusted to 8 with NaOH. After the addition was completed, the stirring reaction was continued for 1.5 hours; after the reaction was completed, it was filtered to obtain a CaSt2@CeSt3 complex precipitate, and then the CaSt2@CeSt3 complex was washed with 80°C deionized water to neutralize it; after washing, it was dried at 60°C for 14 hours; after drying, it was crushed and then passed through a 200-mesh sieve to obtain a CaSt2@CeSt3 complex. The purity of the calcium stearate is ≥98%, and the particle size is 1-5 μm; the Ce(NO3)3 solution is prepared by dissolving Ce(NO3)3·6H2O in deionized water, and the concentration is 0.5 mol / L; the sodium stearate solution is prepared by dissolving sodium stearate in deionized water at 80-90°C, and the concentration is 1 mol / L; the concentration of the NaOH solution is 1 mol / L.

[0019] Step 2: Preparation of stearic acid modified magnesium aluminum hydrotalcite Stearic acid is heated to 70°C to obtain molten stearic acid; dried magnesium aluminum hydrotalcite is added to a high-speed mixer, heated to 80°C, stirred at 800 rpm; the molten stearic acid is slowly dripped into the mixer at a rate of 5 mL / min to 1% of the mass of the magnesium aluminum hydrotalcite, and stirring is continued for 60 minutes after the dripping is completed; after the reaction is completed, the mixture is dried at 80°C for 3 hours; then pulverized in a grinder and passed through a 200 mesh sieve to obtain stearic acid-modified magnesium aluminum hydrotalcite. The magnesium aluminum hydrotalcite has a Mg / Al molar ratio of 3:1 and a particle size of 300-500 nm.

[0020] Step 3: Prepare modified calcium zinc stabilizer The weight ratio of the raw materials used to prepare the modified calcium zinc stabilizer is: 60 parts of stearic acid, 8 parts of nano zinc oxide, 5 parts of CaSt2@CeSt3 complex, 4 parts of stearic acid modified magnesium aluminum hydrotalcite, 10 parts of monoglyceride, 10 parts of polyethylene wax, 5 parts of pentaerythritol, 10 parts of light calcium carbonate, 2 parts of mildew inhibitor, and 3 parts of anti-ultraviolet absorber.

[0021] The anti-ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0022] The mildew preventer is 1,2-benzisothiazolin-3-one.

[0023] The monoglyceride is molecular distilled monoglyceride.

[0024] The particle size of the nano zinc oxide is 50-100 nm.

[0025] Monoglyceride was heated to 60°C and melted, polyethylene wax was added, and heated to 110°C and melted. After stirring and mixing, the mixture was cooled to 80°C, and pentaerythritol, light calcium carbonate, and nano-zinc oxide were added. The mixture was stirred at 800 rpm for 20 minutes to obtain mixture A. The reactor was heated to 70°C and preheated for 40 minutes. Stirring was started at a stirring rate of 300 rpm, stearic acid was added, stirred and melted, and the temperature was raised to 115°C. Mixture A was then added, the stirring rate was increased to 600 rpm, and stirred for 40 minutes. The temperature was then raised to 120°C, and the CaSt2@CeSt3 complex and stearic acid-modified magnesium aluminum hydrotalcite were added in sequence. The stirring rate was increased to 800 rpm, and the mixture was stirred for 40 minutes. A mildew inhibitor and an anti-ultraviolet absorber were then added, the stirring rate was reduced to 600 rpm, and the mixture was stirred for 20 minutes. After standing, the material was discharged and passed through a double-roll cooling tablet press to obtain a modified calcium zinc stabilizer.

[0026] Example 2 Preparation method of modified calcium zinc stabilizer for SPC A method for preparing a modified calcium zinc stabilizer for SPC comprises the following steps: Step 1: Synthesis of CaSt2@CeSt3 complex Calcium stearate was dispersed in deionized water at 65° C., with a solid-liquid ratio of calcium stearate to deionized water of 1:10, and ultrasonic treatment was performed at a power of 400 W for 10 minutes to obtain a calcium stearate suspension.

[0027] The calcium stearate suspension was heated to 75°C, stirred at 900 rpm, and Ce(NO3)3 solution was slowly added dropwise, with a molar ratio of Ce(NO3)3 to calcium stearate of 3:10 and a dropping rate of 3 mL / min. After the addition was completed, the stirring reaction was continued for 10 minutes; then sodium stearate solution was slowly added dropwise, with a molar ratio of sodium stearate to Ce(NO3)3 of 3.5:1 and a dropping rate of 5 mL / min. During the addition process, the pH value was adjusted to 9 with NaOH. After the addition was completed, the stirring reaction was continued for 1.5 hours; after the reaction was completed, it was filtered to obtain a CaSt2@CeSt3 complex precipitate, and then the CaSt2@CeSt3 complex was washed with 85°C deionized water to neutralize it; after washing, it was dried at 70°C for 14 hours; after drying, it was crushed and then passed through a 200-mesh sieve to obtain a CaSt2@CeSt3 complex. The purity of the calcium stearate is ≥98%, and the particle size is 1-5 μm; the Ce(NO3)3 solution is prepared by dissolving Ce(NO3)3·6H2O in deionized water, and the concentration is 0.5 mol / L; the sodium stearate solution is prepared by dissolving sodium stearate in deionized water at 80-90°C, and the concentration is 1 mol / L; the concentration of the NaOH solution is 1 mol / L.

[0028] Step 2: Preparation of stearic acid modified magnesium aluminum hydrotalcite Stearic acid is heated to 80°C to obtain molten stearic acid; dried magnesium aluminum hydrotalcite is added to a high-speed mixer, heated to 90°C, stirred at 1000 rpm; the molten stearic acid is slowly dripped into the mixer at a rate of 10 mL / min to 3% of the mass of the magnesium aluminum hydrotalcite; the stirring is continued for 60 minutes after the dripping is completed; after the reaction is completed, the mixture is dried at 85°C for 3 hours; then the mixture is crushed in a grinder and passed through a 200 mesh sieve to obtain stearic acid-modified magnesium aluminum hydrotalcite. The magnesium aluminum hydrotalcite has a Mg / Al molar ratio of 3:1 and a particle size of 300-500 nm.

[0029] Step 3: Prepare modified calcium zinc stabilizer The weight ratio of the raw materials used to prepare the modified calcium zinc stabilizer is: 70 parts of stearic acid, 6 parts of nano zinc oxide, 4 parts of CaSt2@CeSt3 complex, 3 parts of stearic acid modified magnesium aluminum hydrotalcite, 8 parts of monoglyceride, 8 parts of polyethylene wax, 4 parts of pentaerythritol, 8 parts of light calcium carbonate, 1.5 parts of mildew inhibitor, and 3 parts of anti-ultraviolet absorber.

[0030] The anti-ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0031] The mildew preventer is 1,2-benzisothiazolin-3-one.

[0032] The monoglyceride is molecular distilled monoglyceride.

[0033] The particle size of the nano zinc oxide is 50-100 nm.

[0034] Monoglyceride was heated to 70°C and melted, polyethylene wax was added, and heated to 120°C and melted. After stirring and mixing, the mixture was cooled to 90°C, and pentaerythritol, light calcium carbonate, and nano-zinc oxide were added. The mixture was stirred at 900 rpm for 15 minutes to obtain mixture A. The reactor was heated to 75°C and preheated for 20 minutes. Stirring was started at a stirring rate of 500 rpm, stearic acid was added, stirred and melted, and the temperature was raised to 120°C. Mixture A was then added, the stirring rate was increased to 700 rpm, and stirred for 30 minutes. The temperature was then raised to 130°C, and the CaSt2@CeSt3 complex and stearic acid-modified magnesium aluminum hydrotalcite were added in sequence. The stirring rate was increased to 900 rpm and the reaction was stirred for 30 minutes. A mildew inhibitor and an anti-ultraviolet absorber were then added, the stirring rate was reduced to 700 rpm, and the mixture was stirred for 10 minutes. After standing, the material was discharged and passed through a double-roll cooling tablet press to obtain a modified calcium zinc stabilizer.

[0035] Example 3 Preparation method of modified calcium zinc stabilizer for SPC A method for preparing a modified calcium zinc stabilizer for SPC comprises the following steps: Step 1: Synthesis of CaSt2@CeSt3 complex Calcium stearate was dispersed in deionized water at 65° C., with a solid-liquid ratio of calcium stearate to deionized water of 1:10, and ultrasonic treatment was performed at a power of 400 W for 15 minutes to obtain a calcium stearate suspension.

[0036] The calcium stearate suspension was heated to 80°C, stirred at 900 rpm, and Ce(NO3)3 solution was slowly added dropwise, with a molar ratio of Ce(NO3)3 to calcium stearate of 3:10 and a dropping rate of 3 mL / min. After the addition was completed, the stirring reaction was continued for 10 minutes; then sodium stearate solution was slowly added dropwise, with a molar ratio of sodium stearate to Ce(NO3)3 of 3.5:1 and a dropping rate of 5 mL / min. During the addition process, the pH value was adjusted to 9 with NaOH. After the addition was completed, the stirring reaction was continued for 1 hour; after the reaction was completed, it was filtered to obtain a CaSt2@CeSt3 complex precipitate, and then the CaSt2@CeSt3 complex was washed with 85°C deionized water to neutralize it; after washing, it was dried at 80°C for 12 hours; after drying, it was crushed and then passed through a 200-mesh sieve to obtain a CaSt2@CeSt3 complex. The purity of the calcium stearate is ≥98%, and the particle size is 1-5 μm; the Ce(NO3)3 solution is prepared by dissolving Ce(NO3)3·6H2O in deionized water, and the concentration is 0.5 mol / L; the sodium stearate solution is prepared by dissolving sodium stearate in deionized water at 80-90°C, and the concentration is 1 mol / L; the concentration of the NaOH solution is 1 mol / L.

[0037] Step 2: Preparation of stearic acid modified magnesium aluminum hydrotalcite Stearic acid is heated to 80°C to obtain molten stearic acid; dried magnesium aluminum hydrotalcite is added to a high-speed mixer, heated to 90°C, stirred at 1000 rpm; the molten stearic acid is slowly dripped into the mixer at a rate of 10 mL / min to 3% of the mass of the magnesium aluminum hydrotalcite; the stirring is continued for 30 minutes after the dripping is completed; after the reaction is completed, the mixture is dried at 85°C for 2 hours; then pulverized in a grinder and passed through a 200 mesh sieve to obtain stearic acid-modified magnesium aluminum hydrotalcite. The magnesium aluminum hydrotalcite has a Mg / Al molar ratio of 3:1 and a particle size of 300-500 nm.

[0038] Step 3: Prepare modified calcium zinc stabilizer The weight ratio of the raw materials used to prepare the modified calcium zinc stabilizer is: 80 parts of stearic acid, 5 parts of nano zinc oxide, 2 parts of CaSt2@CeSt3 complex, 2 parts of stearic acid modified magnesium aluminum hydrotalcite, 5 parts of monoglyceride, 5 parts of polyethylene wax, 2 parts of pentaerythritol, 5 parts of light calcium carbonate, 1 part of mildew inhibitor, and 2 parts of anti-ultraviolet absorber.

[0039] The anti-ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0040] The mildew preventer is 1,2-benzisothiazolin-3-one.

[0041] The monoglyceride is molecular distilled monoglyceride.

[0042] The particle size of the nano zinc oxide is 50-100 nm.

[0043] Monoglyceride was heated to 70°C to melt, polyethylene wax was added, and heated to 120°C to melt. After stirring and mixing, the mixture was cooled to 90°C, and pentaerythritol, light calcium carbonate, and nano-zinc oxide were added. The mixture was stirred at 1000 rpm for 15 minutes to obtain mixture A. The reactor was heated to 75°C, preheated for 20 minutes, and stirred at 500 rpm. Stearic acid was added, stirred and melted, and the temperature was raised to 120°C. Mixture A was then added, the stirring rate was increased to 800 rpm, and stirred for 20 minutes. The temperature was then raised to 130°C, and the CaSt2@CeSt3 complex and stearic acid-modified magnesium aluminum hydrotalcite were added in sequence. The stirring rate was increased to 1000 rpm and the reaction was stirred for 20 minutes. A mildew inhibitor and an anti-ultraviolet absorber were then added, the stirring rate was reduced to 800 rpm, and the mixture was stirred for 10 minutes. After standing, the material was discharged and passed through a double-roll cooling tablet press to obtain a modified calcium zinc stabilizer.

[0044] Comparative Example 1 A method for preparing a modified calcium zinc stabilizer comprises the following steps: Step 1: Preparation of stearic acid modified magnesium aluminum hydrotalcite This step is the same as the operation of "preparing stearic acid-modified magnesium aluminum hydrotalcite" in Example 2.

[0045] Step 2: Prepare modified calcium zinc stabilizer The weight ratio of the raw materials used to prepare the modified calcium zinc stabilizer is: 70 parts of stearic acid, 6 parts of nano zinc oxide, 4 parts of calcium stearate, 3 parts of stearic acid-modified magnesium aluminum hydrotalcite, 8 parts of monoglyceride, 8 parts of polyethylene wax, 4 parts of pentaerythritol, 8 parts of light calcium carbonate, 1.5 parts of mildew inhibitor, and 3 parts of anti-ultraviolet absorber.

[0046] The anti-ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0047] The mildew preventer is 1,2-benzisothiazolin-3-one.

[0048] The monoglyceride is molecular distilled monoglyceride.

[0049] The particle size of the nano zinc oxide is 50-100 nm.

[0050] The purity of the calcium stearate is ≥98%, and the particle size is 1-5 μm.

[0051] Monoglyceride was heated to 70°C to melt, polyethylene wax was added, and heated to 120°C to melt. After stirring and mixing, the mixture was cooled to 90°C, and pentaerythritol, light calcium carbonate, and nano zinc oxide were added. The mixture was stirred at 900 rpm for 15 minutes to obtain mixture A. The reactor was heated to 75°C, preheated for 20 minutes, stirred at 500 rpm, stearic acid was added, stirred and melted, and the temperature was raised to 120°C. Mixture A was then added, the stirring rate was increased to 700 rpm, and stirred for 30 minutes. The temperature was then raised to 130°C, and calcium stearate and stearic acid-modified magnesium aluminum hydrotalcite were added in sequence. The stirring rate was increased to 900 rpm, and the mixture was stirred for 30 minutes. A mildew inhibitor and an anti-ultraviolet absorber were then added, the stirring rate was reduced to 700 rpm, and the mixture was stirred for 10 minutes. After standing, the material was discharged and passed through a double-roll cooling tablet press to obtain a modified calcium zinc stabilizer.

[0052] Comparative Example 2 A method for preparing a modified calcium zinc stabilizer comprises the following steps: Step 1: Synthesis of CaSt2@CeSt3 complex This step is the same as the operation of “Synthesis of CaSt2@CeSt3 Composite” in Example 2.

[0053] Step 2: Prepare modified calcium zinc stabilizer The weight ratio of the raw materials used to prepare the modified calcium zinc stabilizer is: 70 parts of stearic acid, 6 parts of nano zinc oxide, 4 parts of CaSt2@CeSt3 complex, 3 parts of magnesium aluminum hydrotalcite, 8 parts of monoglyceride, 8 parts of polyethylene wax, 4 parts of pentaerythritol, 8 parts of light calcium carbonate, 1.5 parts of mildew inhibitor, and 3 parts of anti-ultraviolet absorber.

[0054] The anti-ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0055] The mildew preventer is 1,2-benzisothiazolin-3-one.

[0056] The monoglyceride is molecular distilled monoglyceride.

[0057] The particle size of the nano zinc oxide is 50-100 nm.

[0058] The Mg / Al molar ratio of the magnesium-aluminum hydrotalcite is 3:1, and the particle size is 300-500 nm.

[0059] Monoglyceride was heated to 70°C and melted, polyethylene wax was added, and heated to 120°C and melted. After stirring and mixing, the mixture was cooled to 90°C, and pentaerythritol, light calcium carbonate, and nano-zinc oxide were added. The mixture was stirred at 900 rpm for 15 minutes to obtain mixture A. The reactor was heated to 75°C and preheated for 20 minutes. Stirring was started at a stirring rate of 500 rpm, stearic acid was added, stirred and melted, and the temperature was raised to 120°C. Mixture A was then added, the stirring rate was increased to 700 rpm, and stirred for 30 minutes. The temperature was then raised to 130°C, and CaSt2@CeSt3 composite and magnesium aluminum hydrotalcite were added in sequence. The stirring rate was increased to 900 rpm, and the mixture was stirred for 30 minutes. A mildew inhibitor and an anti-ultraviolet absorber were then added, the stirring rate was reduced to 700 rpm, and the mixture was stirred for 10 minutes. After standing, the material was discharged and passed through a double-roll cooling tablet press to obtain a modified calcium zinc stabilizer.

[0060] Example 4 Performance Test (I) Thermal stability tests were conducted on the modified calcium zinc stabilizers prepared in Examples 1-3 and Comparative Examples 1-2. The modified calcium zinc stabilizers were heated to 180-200°C for 24 hours, and the weight loss rate was calculated. The specific test results are shown in Table 1.

[0061] Table 1

[0062] From the test results in Table 1, it can be seen that the modified calcium zinc stabilizers prepared in Examples 1-3 and Comparative Examples 1-2 have a weight loss rate of 1.01-1.35% after heating for 24 hours, which proves that the modified calcium zinc stabilizers prepared in the present invention have excellent thermal stability.

[0063] (II) SPC samples were prepared using the modified calcium-zinc stabilizers prepared in Examples 1-3 and Comparative Examples 1-2 as raw materials. The raw material ratios by weight were: 50 parts PVC resin, 150 parts calcium powder, 30 parts recycled material, 5 parts modified calcium-zinc stabilizer, 2.0 parts lubricant, and 3.5 parts acrylic copolymer. The resulting SPC samples were subjected to mechanical property testing: tensile strength and elongation at break were measured according to the test methods specified in GB / T 1040. The specific test results are shown in Table 2.

[0064] Table 2

[0065] As can be seen from the test results in Table 2, the SPC samples prepared using the modified calcium zinc stabilizer prepared in Examples 1-3 and Comparative Examples 1-2 as raw materials have a tensile strength of 53.3-56.5 MPa and an elongation at break of 76.9-81.7%, which proves that the SPC samples prepared using the modified calcium zinc stabilizer prepared in the present invention as raw materials have excellent mechanical properties.

[0066] (III) The prepared SPC samples were subjected to a heat aging test: the SPC samples were heated at 200°C, and the color change time of Congo red test paper was recorded. The prepared SPC samples were also subjected to a UV aging test: according to the test method specified in GB / T 16422, the tensile strength retention of the SPC samples was measured after irradiation in a UV aging chamber for 1000 hours. The specific test results are shown in Table 3.

[0067] Table 3

[0068] As shown in the test results in Table 3, the SPC samples prepared using the modified calcium zinc stabilizer prepared in Examples 1-3 and Comparative Examples 1-2 as raw materials have a Congo red test paper color change time of 89-96 min and a tensile strength retention rate of 92.8-94.5% after thermal aging and UV aging, demonstrating that the SPC samples prepared using the modified calcium zinc stabilizer prepared in the present invention as raw materials have excellent anti-aging properties.

[0069] Obviously, there are many specific implementation methods that can be changed under the concept of the present invention. Here, it should be stated that any changes made under the inventive concept of the present invention will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a modified calcium zinc stabilizer for SPC, characterized in that: The method comprises the steps of synthesizing a CaSt2@CeSt3 composite, preparing stearic acid-modified magnesium aluminum hydrotalcite, and preparing a modified calcium zinc stabilizer; The synthesis of CaSt2@CeSt3 complex: the CaSt2@CeSt3 complex is prepared from a calcium stearate suspension, a Ce(NO3)3 solution, and a sodium stearate solution; The preparation of stearic acid-modified magnesium aluminum hydrotalcite comprises modifying magnesium aluminum hydrotalcite with stearic acid to obtain stearic acid-modified magnesium aluminum hydrotalcite; The prepared modified calcium zinc stabilizer adopts raw materials including stearic acid, nano zinc oxide, CaSt2@CeSt3 compound, stearic acid modified magnesium aluminum hydrotalcite, monoglyceride, polyethylene wax, pentaerythritol, light calcium carbonate, mildew inhibitor and anti-ultraviolet absorber.

2. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 1, characterized in that: The raw materials used to prepare the modified calcium zinc stabilizer are as follows: 60-80 parts by weight of stearic acid, 5-8 parts of nano zinc oxide, 2-5 parts of CaSt2@CeSt3 complex, 2-4 parts of stearic acid-modified magnesium aluminum hydrotalcite, 5-10 parts of monoglyceride, 5-10 parts of polyethylene wax, 2-5 parts of pentaerythritol, 5-10 parts of light calcium carbonate, 1-2 parts of mildew inhibitor, and 2-3 parts of anti-ultraviolet absorber.

3. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 1, characterized in that: The synthesis of the CaSt2@CeSt3 complex comprises the following steps: heating a calcium stearate suspension to 70-80°C, stirring at a rate of 800-900 rpm, slowly dropping a Ce(NO3)3 solution, and continuing to stir and react for 10-15 minutes after the dropwise addition; then slowly dropping a sodium stearate solution, adjusting the pH value to 8-9 with NaOH during the dropwise addition, and continuing to stir and react for 1-1.5 hours after the dropwise addition; and after the reaction is completed, filtering, washing, drying, and pulverizing to obtain the CaSt2@CeSt3 complex.

4. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 3, characterized in that: The calcium stearate suspension is prepared by dispersing calcium stearate in deionized water at 60-65° C., with the solid-liquid ratio of calcium stearate to deionized water being 1:10, and performing ultrasonic treatment for 10-15 minutes to obtain a calcium stearate suspension.

5. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 3, characterized in that: The molar ratio of Ce(NO3)3 to calcium stearate is (2-3):

10.

6. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 3, characterized in that: The molar ratio of sodium stearate to Ce(NO3)3 is (3-3.5):

1.

7. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 1, characterized in that: The preparation method of stearic acid-modified magnesium aluminum hydrotalcite comprises the following steps: heating stearic acid to 70-80° C. to obtain molten stearic acid; adding the dried magnesium aluminum hydrotalcite to a high-speed mixer, heating the mixture to 80-90° C., and stirring the mixture at a speed of 800-1000 rpm; slowly dripping the molten stearic acid into the mixer, and continuing to stir and mix the mixture for 30-60 minutes after the dripping is complete; and drying and crushing the mixture after the reaction is completed to obtain the stearic acid-modified magnesium aluminum hydrotalcite.

8. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 7, characterized in that: The amount of the molten stearic acid added to the mixer is 1-3% of the mass of the magnesium-aluminum hydrotalcite.

9. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 1, characterized in that: The modified calcium zinc stabilizer is prepared by heating monoglyceride to 60-70°C and melting it, adding polyethylene wax, heating it to 110-120°C and melting it, stirring and mixing it, then cooling it to 80-90°C, adding pentaerythritol, light calcium carbonate and nano zinc oxide, and stirring it for 15-20 minutes to obtain a mixture A; heating the reactor to 70-75°C, preheating it for 20-40 minutes, starting stirring, adding stearic acid, stirring and melting it, and heating it to 115-120°C; then adding the mixture A, and increasing the stirring rate to 100-150°C. 600-800 rpm, stirring for 20-40 minutes; then, raising the temperature to 120-130°C, adding the CaSt2@CeSt3 complex and stearic acid-modified magnesium aluminum hydrotalcite in sequence, raising the stirring rate to 800-1000 rpm, and stirring for 20-40 minutes; then, adding the mildew inhibitor and the anti-ultraviolet absorber, reducing the stirring rate to 600-800 rpm, and stirring for 10-20 minutes; after standing, discharging the material, and passing it through a double-roll cooling tablet press to obtain a modified calcium zinc stabilizer.

10. The method for preparing a modified calcium zinc stabilizer for SPC according to claim 1, characterized in that: The anti-ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole; and the mildew preventer is 1,2-benzisothiazolin-3-one.

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