Embedded heat stabilizer for PVC (polyvinyl chloride) as well as preparation method and application of embedded heat stabilizer

Abstract

The invention relates to an embedded heat stabilizer for PVC (polyvinyl chloride) as well as a preparation method and application of the embedded heat stabilizer, which can be applied to the field of downstream processing and application of PVC. The preparation method comprises the following steps: firstly, synthesizing a Zn-Sm structure precursor with a hydrotalcite structure through a hydrothermal method, and then carrying out modification treatment through stearic acid to synthesize the Zn-Sm embedded type heat stabilizer. The thermal stabilizer has a relatively better structure and more active centers, so that the adsorption and conversion of HCl in the PVC thermal decomposition process are facilitated, the oxidation resistance is improved through the efficient synergistic effect of rare earth elements samarium and zinc which are introduced into a plurality of orbits and have larger radiuses, and the zinc burning phenomenon caused in the PVC thermal decomposition process is prevented.

Description

Technical Field

[0001] This invention relates to an intercalation-type heat stabilizer for PVC, which can be used as a heat stabilizer in the downstream processing of PVC to improve the thermal stability of the processing, thereby improving the color and stability of the product. Background Technology

[0002] Polyvinyl chloride (PVC) is one of the five major thermoplastic general-purpose resins, second only to polyethylene in production volume. Molded PVC possesses high mechanical strength and good chemical stability, making it widely used in construction, industry, agriculture, and medical fields. However, PVC is difficult to process and mold, and its poor thermal stability makes it prone to decomposition due to HCl removal, degradation, and discoloration. This is because many structural defects in its molecular chain lead to poor thermal stability. Therefore, heat stabilizers need to be added during the production and processing of PVC to improve the product's thermal stability.

[0003] Currently, traditional lead-based heat stabilizers are gradually being replaced by composite heat stabilizers, such as calcium-zinc or barium-zinc composite heat stabilizers and rare-earth composite heat stabilizers, due to their superior performance and low cost but high toxicity. Rare-earth heat stabilizers are a new generation of environmentally friendly PVC heat stabilizers that have developed rapidly in recent years. In addition to excellent heat stabilization performance, they also have coupling and toughening effects, reducing melt viscosity and improving product application and processing performance. However, studies have found that their initial thermal stability is not high, and their initial coloring is poor.

[0004] Hydrotalcite has long been a focus of research in materials science. It has the ability to absorb and neutralize hydrogen chloride, and it also provides thermal stability for PVC. Furthermore, the thermal stabilizing effect is even more pronounced when hydrotalcite is combined with other thermal stabilizing agents. Hydrotalcite contains bound water and has a lamellar structure, which can absorb the heat released by PVC combustion, suppressing smoke production and thus improving the flame retardancy of PVC products. Studies by Soma et al. have found that PVC with added hydrotalcite exhibits the same high oxygen index as Al(OH)3, indicating its good flame retardant effect. Bao Yongzhong et al. synthesized PVC / hydrotalcite nanocomposite resin and further processed it to obtain nanocomposite materials. Tests showed that the addition of hydrotalcite improved the tensile strength and impact strength of the product. Vander VenL et al. studied the thermal stabilizing effect of hydrotalcite with different anionic structures on PVC, finding that the introduction of long-chain stearic acid resulted in better HCl absorption and improved product stability.

[0005] To overcome the shortcomings of existing technologies, this study combines the advantages of hydrotalcite and rare earth thermal stabilizers. Based on the hydrotalcite structure, rare earth elements with large ionic radii and numerous orbitals are introduced, and hydrothermal synthesis is performed under unique conditions to form a hydrotalcite structural carrier. Subsequently, long-chain stearic acid is used for modification, retaining the hydrotalcite anion CO3. 2- At the same time, it replaces and substitutes part of the OH- This comprehensively enhances the adsorption and conversion capacity for HCl and the ability to replace unstable groups in the PVC chain structure. Summary of the Invention

[0006] The purpose of this invention is to provide a highly efficient and environmentally friendly intercalation heat stabilizer for PVC processing applications, its synthesis method, and its application.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] On the one hand, the present invention also provides a method for preparing an interlocking heat stabilizer for PVC, the method comprising the following steps: synthesizing hydrotalcite material as a precursor by hydrothermal method, and then modifying it with stearic acid to obtain the interlocking heat stabilizer.

[0009] Specifically, the preparation method includes the following steps:

[0010] (6) Prepare a mixed aqueous solution containing soluble zinc salt, soluble samarium salt, surfactant, and mineralizer;

[0011] (7) Add a precipitant to the mixed aqueous solution obtained in step (1) and carry out a hydrothermal reaction;

[0012] (8) After the reaction is complete, the mixture is cooled, filtered, washed, dried, and ground to obtain hydrotalcite Zn-Sm-CO3-

[0013] LDHs;

[0014] (9) Using ethanol as a solvent, after dissolving stearic acid, add the hydrotalcite Zn-Sm-CO3- obtained in step (3).

[0015] LDHs, continue stirring in the water bath reaction;

[0016] (10) Cool the slurry obtained in step (4), filter it, wash it, dry it and grind it to obtain the hydrotalcite intercalated heat stabilizer (Zn-Sm)st.

[0017] In this invention, the soluble zinc and samarium salt in step (1) are selected from one or more of zinc chloride, zinc nitrate, samarium nitrate, and samarium chloride. The concentrations of the soluble zinc and samarium salt in the mixed aqueous solution in step (1) are both 0.1-0.4 mol / L, and the preferred molar ratio of soluble zinc and samarium salt is 1-4:1.

[0018] In this invention, the surfactant in step (1) is selected from CTAB (hexadecyltrimethylammonium bromide) and PEG (polyethylene glycol), and its concentration in the mixed aqueous solution in step (1) is 0.027-0.055 mol / L.

[0019] In this invention, the mineralizing agent in step (1) is selected from HF and NaF, wherein the concentration of F ions in the mixed aqueous solution in step (1) is 0.3-1 mol / L.

[0020] In this invention, the precipitant in step (2) is selected from one or more of ammonia, ammonium carbonate, and ammonium bicarbonate. The amount of precipitant added is 0.8-5 mol, based on a total molar amount of zinc and samarium of 1 mol.

[0021] In this invention, the temperature of the hydrothermal reaction in step (2) is 40-60℃, and the reaction time is 30-60 minutes.

[0022] In this invention, the temperature after cooling in step (3) is preferably 20-35℃, the filtration is carried out in a Buchner funnel, and the filter paper used for filtration has a pore size of 0.2-0.5 micrometers; the washing solvent is selected from one or more of deionized water and methanol, and there is no particular limitation on the number of washings, preferably 1-5 times; the drying process is carried out in a constant temperature oven, the drying temperature is 50-60℃, the drying time is 12-24 hours, and the particle size after grinding is 200-500 micrometers.

[0023] In this invention, in step (4), the total molar amount of zinc and samarium in the powder sample is 1 mole, the amount of stearic acid is 0.5-5 mol, the water bath reaction temperature is 70-90℃, and the water bath reaction time is 0.2-1.0 h.

[0024] In this invention, the temperature after cooling in step (5) is preferably 20-35℃, the filtration is carried out in a Buchner funnel, and the pore size of the filter paper used for filtration is 0.1-1μm; the washing solvent is selected from one or more of deionized water and methanol, and there is no particular limitation on the number of washings, preferably 1-5 times; the drying process is carried out in a constant temperature oven, the drying temperature is 50-60℃, the drying time is 12-24h, and the particle size after grinding is 200-500μm.

[0025] On the other hand, the present invention provides an intercalation-type heat stabilizer for PVC prepared by the above method.

[0026] On the other hand, the present invention also provides the application of the intercalation heat stabilizer in improving the thermal stability of PVC.

[0027] Compared with the prior art, the present invention has the following advantages and outstanding effects: the components are environmentally friendly and non-toxic. By modifying the hydrotalcite as a base, its structural characteristics and the high thermal stability achieved through multiple synergistic effects can be fully utilized. Under the same dosage, the heat stabilizer of the present invention has a better effect on improving product stability after combining with rare earth element Sm with an excellent structural basis. Attached Figure Description

[0028] Figure 1 The effect of different heat stabilizers on the whiteness of PVC after heat aging;

[0029] Figure 2 The effect of different heat stabilizers on the whiteness of PVC mixing;

[0030] Figure 3 The effect of different heat stabilizers on the whiteness of PVC during open milling. Detailed Implementation

[0031] Raw materials and sources:

[0032] The chemicals used in this invention—zinc nitrate hexahydrate, zinc chloride, samarium nitrate hexahydrate, samarium chloride hexahydrate, sodium fluoride, cetyltrimethylammonium bromide (CTAB), ethanol, methanol, polyethylene glycol, ammonia (25%), urea, and ammonium carbonate—are all from Macklin Reagents; stearic acid, zinc stearate, barium stearate, dioctyl phthalate, polyethylene wax, and organotin compounds are all from Aladdin Reagents; and the polyvinyl chloride (PVC) used in the test is Wanhua PVC product WH-1000F.

[0033] Performance testing:

[0034] Static thermal stability test: The thermal aging whiteness test of products with different heat stabilizers was carried out using the PVC thermal aging whiteness test method in accordance with GB / T 15595-2008.

[0035] Dynamic thermal stability test (internal mixing): The test was conducted on a torque rheometer. The feed mass (after mixing) was 60g, the temperature of all three zones of the mixer was 180℃, the rotation speed was 30r / min, and the sample block was taken out after internal mixing for 10min. It was then molded at 180℃ and its whiteness value was tested.

[0036] Dynamic thermal stability test (open mill): The test was conducted on a two-roll open mill with a feed mass (after mixing) of 30g, a front and rear roll temperature of 190℃, a rotation speed of 24:16r / min, and a sample sheet thickness (0.3mm) was taken every 10 minutes after 30 minutes of open milling. Subsequently, its whiteness value was tested.

[0037] The technical solution of the present invention will be further described below with reference to the embodiments:

[0038] In the following examples and comparative examples, HT represents the hydrothermal method, CP represents the coprecipitation method, SM represents the saponification method, and DD represents the metathesis method.

[0039] Example 1: Preparation of (Zn-Sm)st-HT-1 heat stabilizer

[0040] a) Add 100g of deionized water to a 200ml beaker and stir on a magnetic stirrer. Weigh out 0.02mol of zinc chloride and 0.02mol of samarium nitrate hexahydrate and add them to the beaker in sequence. Then add 1g of CTAB and 0.3g of NaF and keep stirring for 1h.

[0041] b) Take the mixed solution obtained in step a) and continue to stir and mix it in a water bath at 50°C for 30 minutes. Then add 0.04 mol of urea and continue to stir in a water bath for 30 minutes.

[0042] c) Transfer the mixed solution obtained in step b) to a 150 ml hydrothermal reactor and react hydrothermally at 120 °C for 12 h, then cool to room temperature;

[0043] d) The reaction solution obtained in step c) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain Zn-Sm-CO3-LDHs-1.

[0044] e) Place a 500ml three-necked flask in a water bath, set the temperature to 70℃, mechanically stir at 450r / min, add 250ml of ethanol, then weigh out 0.02mol of stearic acid and slowly add it, continue stirring for 30min until the solid is completely melted;

[0045] f) Slowly add the powder obtained in step d) into the flask in e), and after stirring thoroughly, keep it for 0.2 hours, then cool it to room temperature;

[0046] g) The reaction solution obtained in step f) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain (Zn-Sm)st-HT-1 heat stabilizer.

[0047] Example 2: Preparation of (Zn-Sm)st-HT-2 heat stabilizer

[0048] a) Add 100g of deionized water to a 200ml beaker and stir on a magnetic stirrer. Weigh 0.02mol of zinc nitrate hexahydrate and 0.02mol of samarium chloride hexahydrate and add them to the beaker in sequence. Then add 2g of PEG and 1g of HF (1% concentration) and keep stirring for 1h.

[0049] b) Take the mixed solution obtained in step a) and stir it in a water bath at 40°C for 30 minutes, then add 0.08 mol of ammonium carbonate and continue stirring in a water bath for 30 minutes;

[0050] c) Transfer the mixed solution obtained in step b) to a 150 ml hydrothermal reactor and react hydrothermally at 100 °C for 12 h, then cool to room temperature;

[0051] d) The reaction solution obtained in step c) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground, and sieved through a 60-mesh sieve to obtain Zn-Sm-CO3-

[0052] LDHs-2;

[0053] e) Place a 500ml three-necked flask in a water bath, set the temperature to 80℃, mechanically stir at 500r / min, add 250ml of ethanol, then weigh out 0.04mol of stearic acid and slowly add it, continue stirring for 30min until the solid is completely melted;

[0054] f) Slowly add the powder obtained in step d) into the flask in e), and after stirring thoroughly, keep it for 0.4 h, then cool it to room temperature;

[0055] g) The reaction solution obtained in step f) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain (Zn-Sm)st-HT-2 heat stabilizer.

[0056] Example 3: Preparation of (Zn-Sm)st-HT-3 heat stabilizer

[0057] a) Add 100g of deionized water to a 200ml beaker and stir on a magnetic stirrer. Weigh out 0.03mol of zinc nitrate hexahydrate and 0.01mol of samarium nitrate hexahydrate and add them to the beaker in sequence. Then add 1.5g of CTAB and 0.5g of HF (1%).

[0058] (Concentration), keep stirring for 1 hour;

[0059] b) Take the mixed solution obtained in step a) and stir it in a water bath at 50°C for 30 minutes, then add 0.16 mol of ammonium carbonate and continue stirring in a water bath for 30 minutes;

[0060] c) Transfer the mixed solution obtained in step b) to a 150 ml hydrothermal reactor and react hydrothermally at 120 °C for 12 h, then cool to room temperature;

[0061] d) The reaction solution obtained in step c) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground, and sieved through a 60-mesh sieve to obtain Zn-Sm-CO3-

[0062] LDHs-3;

[0063] e) Place a 500ml three-necked flask in a water bath, set the temperature to 90℃, mechanically stir at 550r / min, add 250ml of ethanol, then weigh out 0.08mol of stearic acid and slowly add it, continue stirring for 30min until the solid is completely melted;

[0064] f) Slowly add the powder obtained in step d) into the flask in e), stir thoroughly and keep for 1 hour, then cool to room temperature;

[0065] g) The reaction solution obtained in step f) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain (Zn-Sm)st-HT-3 heat stabilizer.

[0066] Example 4: Preparation of (Zn-Sm)st-HT-4 heat stabilizer

[0067] a) Add 100g of deionized water to a 200ml beaker and stir on a magnetic stirrer. Weigh 0.03mol of zinc nitrate hexahydrate and 0.01mol of samarium nitrate hexahydrate and add them to the beaker in sequence. Then add 1.5g of PEG and 0.5g of NaF and keep stirring for 1h.

[0068] b) Take the mixed solution obtained in step a) and stir it in a water bath at 50°C for 30 minutes, then add 0.12 mol of ammonium carbonate and continue stirring in a water bath for 30 minutes;

[0069] c) Transfer the mixed solution obtained in step b) to a 150 ml hydrothermal reactor and react hydrothermally at 120 °C for 12 h, then cool to room temperature;

[0070] d) The reaction solution obtained in step c) was filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain Zn-Sm-CO3-LDHs-4.

[0071] e) Place a 500ml three-necked flask in a water bath, set the temperature to 80℃, stir mechanically at 500r / min, add 250ml of ethanol, then weigh out 0.12mol of stearic acid and slowly add it, continue stirring for 30min until the solid is completely melted;

[0072] f) Slowly add the powder obtained in step d) into the flask in e), and after stirring thoroughly, keep it for 0.5 hours, then cool it to room temperature;

[0073] g) The reaction solution obtained in step f) was filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain (Zn-Sm)st-HT-4 heat stabilizer.

[0074] Example 5: Preparation of (Zn-Sm)st-HT-5 heat stabilizer

[0075] a) Add 100g of deionized water to a 200ml beaker and stir on a magnetic stirrer. Weigh out 0.032mol of zinc nitrate hexahydrate and 0.008mol of samarium nitrate hexahydrate and add them to the beaker in sequence. Then add 1.0g of PEG and 0.5g of NaF and keep stirring for 1h.

[0076] b) Take the mixed solution obtained in step a) and stir it in a water bath at 40°C for 30 minutes, then add 0.12 mol of ammonium carbonate and continue stirring in a water bath for 30 minutes;

[0077] c) Transfer the mixed solution obtained in step b) to a 150 ml hydrothermal reactor and react hydrothermally at 140 °C for 8 h, then cool to room temperature;

[0078] d) The reaction solution obtained in step c) was filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain Zn-Sm-CO3-LDHs-5.

[0079] e) Place a 500ml three-necked flask in a water bath, set the temperature to 90℃, mechanically stir at 500r / min, add 250ml of ethanol, then weigh out 0.16mol of stearic acid and slowly add it, continue stirring for 30min until the solid is completely melted;

[0080] f) Slowly add the powder obtained in step d) into the flask in e), and after stirring thoroughly, keep it for 0.6 hours, then cool it to room temperature;

[0081] g) The reaction solution obtained in step f) was filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 h, ground and sieved through a 60-mesh sieve to obtain (Zn-Sm)st-HT-5 heat stabilizer.

[0082] Example 6: Preparation of (Zn-Sm)st-HT-6 heat stabilizer

[0083] a) Add 100g of deionized water to a 200ml beaker and stir on a magnetic stirrer. Weigh out 0.03mol of zinc chloride and 0.01mol of samarium chloride hexahydrate and add them to the beaker in sequence. Then add 1.0g of PEG and 0.6g of NaF and keep stirring for 1h.

[0084] b) Take the mixed solution obtained in step a) and stir it in a water bath at 50°C for 30 minutes, then add 0.12 mol of ammonium carbonate and continue stirring in a water bath for 30 minutes;

[0085] c) Transfer the mixed solution obtained in step b) to a 150 ml hydrothermal reactor and react hydrothermally at 120 °C for 14 h, then cool to room temperature;

[0086] d) The reaction solution obtained in step c) was filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain Zn-Sm-CO3-LDHs-6.

[0087] e) Place a 500ml three-necked flask in a water bath, set the temperature to 75℃, mechanically stir at 500r / min, add 250ml of ethanol, then weigh out 0.2mol of stearic acid and slowly add it, stirring continuously for 30min until the solid is completely melted;

[0088] f) Slowly add the powder obtained in step d) into the flask in e), and after stirring thoroughly, keep it for 0.8 hours, then cool it to room temperature;

[0089] g) The reaction solution obtained in step f) was filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain (Zn-Sm)st-HT-6 heat stabilizer.

[0090] The mainstream synthesis processes for rare earth stearate heat stabilizers employ saponification and metathesis methods. Based on relevant literature, the synthesis of hydrotalcite also involves coprecipitation, which is illustrated below by comparing the proportions (using the optimal proportions from the hydrothermal method).

[0091] Comparative Example 1: Preparation of (Zn-Sm)st-CP heat stabilizer

[0092] a) Add 100g of deionized water to a 200ml beaker and stir on a magnetic stirrer. Weigh out 0.03mol of zinc chloride and 0.01mol of samarium chloride hexahydrate and add them to the beaker in sequence.

[0093] b) Take the mixed solution obtained in step a) and stir it in a water bath at 50°C for 30 minutes. Add 0.2 mol of ammonia water and continue stirring in the water bath for 30 minutes. Then cool it down to room temperature.

[0094] c) The reaction solution obtained in step b) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain Zn-Sm-OH-LDHs-6.

[0095] d) Place a 500ml three-necked flask in a water bath, set the temperature to 80℃, stir mechanically at 500r / min, add 250ml of ethanol, then weigh out 0.12mol of stearic acid and slowly add it, continue stirring for 30min until the solid is completely melted;

[0096] e) Slowly add the powder obtained in step c) into the flask in e), and after stirring thoroughly, keep it for 0.5 hours, then cool it to room temperature;

[0097] f) The reaction solution obtained in step e) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain (Zn-Sm)st-CP heat stabilizer.

[0098] Comparative Example 2: Preparation of (Zn-Sm)st-SM heat stabilizer

[0099] MCln+n NaOH+n RCOOH→(RCOO)nM+n NaCl+n H2O

[0100] In the formula: M - rare earth elements, zinc; n - the valence of the element.

[0101] a) Weigh 0.03 mol zinc chloride and 0.01 mol samarium chloride hexahydrate and add them to a beaker in sequence. Add water to prepare a 45% solution and then prepare a 50% sodium hydroxide solution.

[0102] b) Place a 500ml three-necked flask in a water bath without initial heating, mechanically stir at 500 rpm, add 200ml of water, then add...

[0103] a) A mixed metal solution, 85% alkaline solution, and 0.16 mol stearic acid were prepared.

[0104] c) Heat the water bath to 70°C and keep it at that temperature for 15 minutes. Then, add the remaining diluted alkali solution dropwise over 20 minutes. Continue to keep the reaction at that temperature for 15 minutes, and then cool it down to room temperature.

[0105] d) The reaction solution obtained in step c) is filtered in a vacuum filtration flask, washed with deionized water, dried at 50°C for 12 hours, ground and sieved through a 60-mesh sieve to obtain (Zn-Sm)st-SM heat stabilizer.

[0106] Comparative Example 3: Preparation of (Zn-Sm)st-DD heat stabilizer

[0107] a) Weigh 0.03 mol zinc chloride and 0.01 mol samarium chloride hexahydrate and add them to a beaker in sequence. Add water to prepare a 45% solution and then prepare a 50% sodium hydroxide solution.

[0108] b) Place a 500ml three-necked flask in a water bath, set the temperature to 80℃, stir mechanically at 500r / min, add 250ml of ethanol, then weigh out 0.12mol of stearic acid and slowly add it, continue stirring for 30min until the solid is completely melted;

[0109] c) First, add the alkaline solution from a) dropwise to b), and keep stirring while reacting for 30 minutes;

[0110] d) Add the salt solution from a) dropwise to b), and react with stirring for 30 minutes, then cool to room temperature;

[0111] e) Take the reaction solution obtained in step d) and filter it in a vacuum filtration flask. Wash it with deionized water, dry it at 50°C for 12 hours, grind it and sieve it through a 60-mesh sieve to obtain (Zn-Sm)st-DD.

[0112] The performance of the heat stabilizer of the present invention will be explained below with reference to application examples:

[0113] Application Example 1:

[0114] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-HT-1. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0115] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-HT-1, add 5g of DOP and mix thoroughly. Weigh 60-62g of the sample and test it on a torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and the mixing is carried out for 10min. After mixing, take out the sample block, weigh 50-55g, and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0116] Whiteness test of open mill: Weigh 30g of PVC powder, weigh 0.3g of heat stabilizer (Zn-Sm) st-HT-1, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the rotation speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0117] Application Example 2: The preparation method of the heat stabilizer is the same as in Example 2.

[0118] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-HT-2. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0119] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-HT-2, add 5g of DOP and mix thoroughly. Weigh 60-62g of sample and test on torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and after intensive mixing for 10min, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0120] Whiteness test of open mill: Weigh 30g of PVC powder and 0.3g of heat stabilizer (Zn-Sm) st-HT-2, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0121] Application Example 3: The preparation method of the heat stabilizer is the same as in Example 3.

[0122] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-HT-3. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0123] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-HT-3, add 5g of DOP and mix thoroughly. Weigh 60-62g of the sample and test it on a torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and the mixing is carried out for 10min. After mixing, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0124] Whiteness test of open mill: Weigh 30g of PVC powder and 0.3g of heat stabilizer (Zn-Sm) st-HT-3, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0125] Application Example 4: The preparation method of the heat stabilizer is the same as in Example 4.

[0126] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-HT-4. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0127] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-HT-4, add 5g of DOP and mix thoroughly. Weigh 60-62g of the sample and test it on a torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and the mixing is carried out for 10min. After mixing, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0128] Whiteness test of open mill: Weigh 30g of PVC powder and 0.3g of heat stabilizer (Zn-Sm) st-HT-4, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0129] Application Example 5: The preparation method of the heat stabilizer is the same as in Example 5.

[0130] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-HT-5. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0131] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-HT-5, add 5g of DOP and mix thoroughly. Weigh 60-62g of sample and test on torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and after intensive mixing for 10min, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0132] Whiteness test of open mill: Weigh 30g of PVC powder and 0.3g of heat stabilizer (Zn-Sm) st-HT-5, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0133] Application Example 6: The preparation method of the heat stabilizer is the same as in Example 6.

[0134] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-HT-6. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0135] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-HT-6, add 5g of DOP and mix thoroughly. Weigh 60-62g of sample and test on torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and after intensive mixing for 10min, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0136] Whiteness test of open mill: Weigh 30g of PVC powder and 0.3g of heat stabilizer (Zn-Sm) st-HT-6, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0137] Application Example 7: The preparation method of the heat stabilizer is the same as that of Comparative Example 1.

[0138] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-CP. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0139] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-CP, add 5g of DOP and mix thoroughly. Weigh 60-62g of sample and test on torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and after intensive mixing for 10min, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0140] Whiteness test of open mill: Weigh 30g of PVC powder and 0.3g of heat stabilizer (Zn-Sm) st-CP, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0141] Application Example 8: The preparation method of the heat stabilizer is the same as that of Comparative Example 2.

[0142] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-SM. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0143] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-SM, add 5g of DOP and mix thoroughly. Weigh 60-62g of sample and test on torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and after intensive mixing for 10min, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0144] Whiteness test of open mill: Weigh 30g of PVC powder and 0.3g of heat stabilizer (Zn-Sm) st-SM, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0145] Application Example 9: The preparation method of the heat stabilizer is the same as that of Comparative Example 3.

[0146] Aging Whiteness Test: Weigh 20g of PVC powder and 0.2g of heat stabilizer (Zn-Sm) st-DD. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0147] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.5g of heat stabilizer (Zn-Sm) st-DD, add 5g of DOP and mix thoroughly. Weigh 60-62g of sample and test on torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and after intensive mixing for 10min, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0148] Whiteness test of open mill: Weigh 30g of PVC powder and 0.3g of heat stabilizer (Zn-Sm) st-DD, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0149] Application Example 10: An existing Ba-Zn heat stabilizer was selected as Comparative Example 4.

[0150] Aging Whiteness Test: Weigh 20g of PVC powder, and weigh 0.1g each of heat stabilizers Ba stearate and Zn stearate. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Grind the sample into powder, fill it into a 10mm transparent cuvette, and test the whiteness of the sample in reflectance mode.

[0151] Whiteness test of intensive mixing: Weigh 60g of PVC powder, weigh 0.25g each of heat stabilizer stearic acid Ba and stearic acid Zn, add 5g of DOP and mix thoroughly. Weigh 60-62g of sample and test on torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and after intensive mixing for 10min, take out the sample block, weigh 50-55g and press it into a sheet with a thickness of 1mm in a 180℃ molding press. Then test the whiteness value of the sample sheet.

[0152] Whiteness test of open mill: Weigh 30g of PVC powder, weigh 0.15g each of heat stabilizer stearic acid Ba and stearic acid Zn, add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0153] Application Example 11: An existing organotin heat stabilizer was selected as Comparative Example 5.

[0154] Aging whiteness test: Weigh 20g of PVC powder and 0.2g of organotin heat stabilizer. Mix thoroughly, then weigh 10-10.3g of the mixed sample and place it in a constant temperature oven at 160℃ (stabilize for at least 30 minutes). Heat for 10 minutes, then remove and cool to room temperature in a drying basin. Subsequently, grind the sample into powder, fill it into a transparent cuvette (10mm), and test the whiteness of the sample in reflectance mode.

[0155] Whiteness test of intensive mixing: Weigh 60g of PVC powder, 0.5g of heat stabilizer organotin, 1g of PE wax, and 0.5g of stearic acid. Add 5g of DOP and mix thoroughly. Weigh 60-62g of the sample and test it on a torque rheometer. The temperature of all three zones of the mixer is 180℃, the speed is 30r / min, and the mixing is intensive for 10min. Take out the sample block, weigh 50-55g, and press it into a sheet with a thickness of 1mm in a molding press at 180℃. Then test the whiteness value of the sample sheet.

[0156] Whiteness test of open mill: Weigh 30g of PVC powder, 0.3g of heat stabilizer organotin, 0.4g of PE wax, and 0.2g of stearic acid. Add 12g of DOP and mix thoroughly. Test on a two-roll open mill with the front and rear roll temperatures at 190℃ (stabilized for more than 30 minutes) and the rotation speed at 24:16r / min. After 30 minutes of open milling, take a sample every 10 minutes to test the thickness (0.3mm), and then test the whiteness value of the sample.

[0157] Figure 1 The study revealed the differences in whiteness after thermal aging among different heat stabilizer samples. It was found that the (Zn-Sm)st-HT-4 sample had the highest whiteness, indicating that it provided better protection for PVC during heating and slowed down continuous aging and the formation of double bonds.

[0158] Figure 2 The results of mixing different heat stabilizers show that the samples synthesized by hydrothermal method have higher whiteness. Thanks to the unique structural advantages of hydrothermal method, the absorption and conversion of HCl released during the mixing process by the synthesized hydrotalcite structure sample is the fundamental reason for its excellent performance. In addition, after modification with stearic acid, its active groups can replace unstable groups such as allyl chloride on the PVC chain, thus preventing the continuous aging process.

[0159] Figure 3 The results of open refining with different heat stabilizers show relatively small differences compared to internal refining, because HCl is released and escaped under open refining conditions, thus avoiding its own autocatalytic phenomenon. The low whiteness of the saponification samples obtained from internal refining may be due to high ion concentration, high sodium soap gelation energy, and low solubility, leading to insufficient stearic acid displacement reaction and insufficient active groups. Compared to the currently used Ba-Zn heat stabilizer system, the (Zn-Sm)st system benefits from its hydrotalcite structure, carrying more CO32-. 2- Anionic groups can effectively adsorb and convert HCl, while rare earth ions with large ionic radii can form ionic bonds with organic ligands, preventing zinc burning of zinc stearate. The synergistic effect of Zn-Sm gives it highly efficient and excellent thermal stability.

Claims

1. A method for preparing an interlocking heat stabilizer for PVC, the method comprising the following steps: synthesizing hydrotalcite material as a precursor by hydrothermal method, and then modifying it with stearic acid to obtain the interlocking heat stabilizer.

2. The method as described in claim 1, characterized in that, Includes the following steps: (1) Prepare a mixed aqueous solution containing soluble zinc salt, soluble samarium salt, surfactant and mineralizer; (2) Add a precipitant to the mixed aqueous solution obtained in step (1) and carry out a hydrothermal reaction; (3) After the reaction is complete, the mixture is cooled, filtered, washed, dried and ground to obtain hydrotalcite Zn-Sm-CO3-LDHs; (4) Using ethanol as a solvent, after dissolving stearic acid, add the hydrotalcite Zn-Sm-CO3-LDHs obtained in step (3) and continue stirring in a water bath. (5) Cool, filter, wash, dry and grind the slurry obtained in step (4) to obtain hydrotalcite intercalated heat stabilizer (Zn-Sm)st.

3. The method as described in claim 1 or 2, characterized in that, In step (1), the soluble zinc and samarium salt are selected from one or more of zinc chloride, zinc nitrate, samarium nitrate, and samarium chloride. The concentrations of the soluble zinc and samarium salt in the mixed aqueous solution in step (1) are both 0.1-0.4 mol / L, and the preferred molar ratio of soluble zinc and samarium salt is 1-4:

1.

4. The method according to any one of claims 1-3, characterized in that, In step (1), the surfactant is selected from CTAB (hexadecyltrimethylammonium bromide) and PEG (polyethylene glycol), and its concentration in the mixed aqueous solution in step (1) is 0.027-0.055 mol / L; and / or, in step (1), the mineralizer is selected from HF and NaF, wherein the concentration of F ions in the mixed aqueous solution in step (1) is 0.3-1 mol / L.

5. The method according to any one of claims 1-4, characterized in that, The precipitant in step (2) is selected from one or more of ammonia, ammonium carbonate, and ammonium bicarbonate. The amount of precipitant added is 0.8-5 mol, with the total molar amount of zinc and samarium being 1 mol.

6. The method according to any one of claims 1-5, characterized in that, The hydrothermal reaction temperature in step (2) is 40-60℃ and the reaction time is 30-60 minutes; and / or, the particle size after grinding in step (3) is 200-500 micrometers.

7. The method according to any one of claims 1-6, characterized in that, In step (4), the total molar amount of zinc and samarium in the powder sample is 1 mole, the amount of stearic acid is 0.5-5 mol; and / or, the water bath reaction temperature is 70-90℃; the water bath reaction time is 0.2-1.0 h.

8. The method according to any one of claims 1-7, characterized in that, The preferred temperature after cooling in step (5) is 20-35℃, and / or the filtration is carried out in a Buchner funnel, and the filter paper used for filtration has a pore size of 0.1-1μm; and / or the washing solvent is selected from one or more of deionized water and methanol; and / or the drying temperature is 50-60℃, the drying time is 12-24h, and the particle size after grinding is 200-500μm.

9. A PVC intercalating heat stabilizer prepared by the method according to any one of claims 1-8.

10. The use of the intercalation heat stabilizer for PVC prepared by the method of any one of claims 1-8 or the intercalation heat stabilizer as described in claim 9 in improving the thermal stability of PVC.

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