Amino-functionalized MOFs composite thermal stabilizer and preparation method and application thereof

Abstract

This invention discloses an amino-functionalized MOFs composite heat stabilizer, its preparation method, and its application, belonging to the field of polymer materials technology. The amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts amino-functionalized protonated MOFs, 20-30 parts zinc stearate, and 10-15 parts polyol. The amino-functionalized MOFs stabilizer provided by this invention utilizes the large specific surface area and numerous pores of MOFs to adsorb HCl generated during PVC processing, while -NH3... + MOFs form hydrogen bonds or electrostatic interactions with HCl, or undergo ion exchange reactions to generate -NH3Cl; after protonation, the inner surface of the pores of MOFs carries positive charges or acidic groups, which can better selectively adsorb polar molecules such as HCl; zinc stearate inhibits the degradation of PVC by HCl through its reaction with HCl and its cross-linking reaction with PVC; ZnCl2 generated during the reaction of zinc stearate with hydrogen chloride complexes with polyols, and the three work together to improve the thermal stability of PVC.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an amino-functionalized MOFs composite heat stabilizer, its preparation method, and its application. Background Technology

[0002] Polyvinyl chloride (PVC) is a widely used synthetic resin material. Due to its excellent chemical resistance, electrical insulation, abrasion resistance, and processability, it is widely used in building materials, electronics, automobiles, packaging, and other fields. However, PVC is susceptible to the effects of heat and light during processing and use, leading to decomposition, discoloration, and performance degradation. Therefore, the application of heat stabilizers is crucial for ensuring the quality and durability of PVC products.

[0003] The primary function of PVC heat stabilizers is to prevent or delay the thermal degradation of PVC during heat processing and long-term use. Traditional heat stabilizers include metal soaps such as lead salts, barium zinc, and cadmium zinc, as well as organotin and rare earth stabilizers. While these heat stabilizers are indeed effective in practical applications, lead salt heat stabilizers are gradually being phased out due to increasingly stringent environmental regulations and growing public concern for health and environmental protection. Although organotin stabilizers are more environmentally friendly than lead stabilizers, they still possess a degree of toxicity. Furthermore, organotin compounds may migrate to surfaces or leach from PVC materials during use, especially under high-temperature or prolonged conditions, leading to decreased product performance and potential health risks. Compared to traditional lead salt and organotin stabilizers, rare earth environmentally friendly stabilizers are often more expensive, which may hinder their adoption in some price-sensitive applications. Therefore, developing environmentally friendly and efficient PVC heat stabilizers has become an urgent technical challenge.

[0004] CN 115010947 A discloses a polyvinyl chloride (PVC) stabilizer, its preparation method, and its application. Under alkaline conditions, small molecules containing functional groups are grafted onto a metal-organic framework material using diacyl chloride. The stabilizer prepared has a stability time of approximately 30 minutes. The preparation process of this stabilizer is complex, and its stability time can be further improved. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the purpose of this invention is to provide an amino-functionalized MOFs composite heat stabilizer.

[0006] Another object of the present invention is to provide an application of an amino-functionalized MOFs composite heat stabilizer in the preparation of PVC materials.

[0007] Another object of the present invention is to provide a PVC pipe material.

[0008] Another object of the present invention is to provide a PVC pipe.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts amino-functionalized protonated MOFs, 20-30 parts zinc stearate, and 10-15 parts polyol.

[0011] The amino-functionalized protonated MOFs are at least one of amino-functionalized protonated UiO-66, MIL-101, MOF-5, and ZIF-8.

[0012] This invention utilizes amino-functionalized protonated MOFs, zinc stearate, and polyols to prepare a composite heat stabilizer. Due to the large specific surface area and numerous pores in the MOFs structure, intermolecular forces can bind gas within the framework pores. Therefore, this composite heat stabilizer is used in the preparation of PVC materials. The amino-functionalized protonated MOFs can adsorb HCl generated during PVC processing, and the amino groups on their ligands, after protonation, form -NH3. + Firstly, it can form hydrogen bonds or electrostatic interactions with HCl, or undergo ion exchange reactions to generate -NH3Cl. Secondly, after protonation, the inner surface of the pores of MOFs carries positive charges or acidic groups, which can better selectively adsorb polar molecules HCl, thereby improving the thermal stability of PVC.

[0013] Zinc stearate, as a heat stabilizer for PVC, will undergo the following reactions: (1) Capturing HCl: Zinc heat stabilizer can react with HCl, which can inhibit the degradation effect of HCl on PVC to a certain extent; (2) Crosslinking reaction: Conjugated double bonds are generated during the decomposition of PVC. Double bonds are easily attacked by external factors such as heat, light, and oxygen, forming highly active free radicals, which will cause the material to degrade and discolor, thus leading to a decrease in the thermal stability of PVC material. Zinc stearate can undergo a crosslinking reaction with the conjugated double bonds in the material, making the material structure more stable. This crosslinking effect helps to improve the heat resistance and mechanical properties of the material.

[0014] The ZnCl2 generated during the reaction of zinc stearate and hydrogen chloride exhibits catalytic activity, potentially accelerating PVC degradation and causing discoloration. This is because zinc chloride promotes the dehydrochlorination reaction of PVC, forming a conjugated double bond system that causes the material to turn yellow or brown. Amino-functionalized MOFs can absorb most of the hydrogen chloride generated during decomposition, reducing this reaction and effectively improving the thermal stability of PVC. Polyols, as auxiliary stabilizers, can form complexes with zinc chloride, reducing the amount of free zinc chloride in the system.

[0015] It should be noted that zinc stearate can also be used as an external lubricant, which can reduce the friction between molecular chains and between PVC and processing equipment during PVC processing, thereby reducing frictional heat generation during processing. This lubrication helps to prevent premature decomposition of PVC and improve the initial thermal stability of the PVC system.

[0016] It should be noted that the amino-functionalized protonation described in this invention refers to first amino-functionalizing the MOF material and then protonating it.

[0017] Preferably, the amino-functionalized protonated MOFs are amino-functionalized protonated UiO-66.

[0018] Traditional MOF structures have relatively low hydrothermal and chemical stability. The UiO-66 used in this invention has outstanding hydrothermal and chemical stability, and its crystal structure can remain stable at 500℃.

[0019] More specifically, the amino functionalization includes replacing the organic ligands of UiO-66, MIL-101, or MOF-5 with organic ligands containing amino groups, or modifying ZIF-8 with organic amines.

[0020] More specifically, the amino-containing organic ligand is at least one of 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, and 2,3-diaminoterephthalic acid.

[0021] More specifically, the organic amine is at least one of ethylenediamine, 1,3-propanediamine, and 1,4-butanediamine.

[0022] More specifically, the organic amine modification of ZIF-8 includes the following steps:

[0023] ZIF-8 was vacuum activated and then placed in saturated vapor of ethylenediamine. After that, it was added to an aqueous solution of ethylenediamine, separated and dried to obtain amino-functionalized ZIF-8.

[0024] Specifically, the acid used for protonation is at least one of phosphoric acid, formic acid, and acetic acid.

[0025] More specifically, the protonation includes the following steps:

[0026] The amino-functionalized MOFs were placed in an acidic solution, stirred, separated, and dried to obtain the amino-functionalized protonated MOFs.

[0027] Preferably, the polyol is at least one of pentaerythritol, pentaerythritol distearate, and pentaerythritol monostearate.

[0028] Specifically, the preparation method of the composite heat stabilizer includes the following steps:

[0029] Amino-functionalized protonated MOFs, zinc stearate, and polyols are mixed evenly to obtain the amino-functionalized MOFs composite heat stabilizer.

[0030] This invention also protects the application of an amino-functionalized MOF composite stabilizer in the preparation of PVC materials.

[0031] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5-15 parts inorganic filler, 3-8 parts composite heat stabilizer, 1-2 parts lubricant, and 1-5 parts processing aid.

[0032] Specifically, the inorganic filler is at least one of calcium carbonate, talc, and silica fume.

[0033] Specifically, the lubricant is at least one of paraffin wax, stearic acid, and polyethylene wax.

[0034] Specifically, the processing aid is at least one of MBS (methyl methacrylate-butadiene-styrene copolymer), CPE (chlorinated polyethylene), and POE (ethylene-octene copolymer).

[0035] Specifically, the preparation method of the PVC pipe material includes the following steps:

[0036] Polyvinyl chloride, inorganic filler, the composite heat stabilizer, lubricant, and processing aid are mixed evenly to obtain the PVC pipe material.

[0037] A PVC pipe material, comprising the PVC pipe material.

[0038] The method for preparing the PVC pipe includes the following steps:

[0039] The PVC pipe material is melted, extruded, and shaped to obtain the PVC pipe.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The amino-functionalized protonated MOF stabilizer provided by this invention utilizes the characteristics of MOFs—large specific surface area and numerous structural pores—to adsorb HCl and -NH3 generated during PVC processing. + MOFs form hydrogen bonds or electrostatic interactions with HCl, or undergo ion exchange reactions to generate -NH3Cl; after protonation, the inner surface of the pores of MOFs carries positive charges or acidic groups, which can better selectively adsorb polar molecules such as HCl; zinc stearate inhibits the degradation of PVC by HCl through its reaction with HCl and its cross-linking reaction with PVC; ZnCl2 generated during the reaction of zinc stearate with hydrogen chloride complexes with polyols, and the three work together to improve the thermal stability of PVC.

[0042] The PVC material prepared by the amino-functionalized MOFs stabilizer provided by the present invention has excellent thermal stability, with a thermal stability time ≥45 min. Attached Figure Description

[0043] Figure 1 The figures show the test results of the torque rheometer for the examples and comparative examples. Detailed Implementation

[0044] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0045] Polyvinyl chloride: Manufacturer: Xinjiang Zhongtai (Group) Co., Ltd., Model: SG-5.

[0046] The preparation method of amino-functionalized UiO-66 includes the following steps:

[0047] N,N-dimethylformamide (DMF), deionized water, and glacial acetic acid were added to the liner and stirred until homogeneous. ZrCl4 was added, and the mixture was stirred for 10 minutes to obtain mixed solution A. A 0.4M 2-aminoterephthalic acid / DMF solution was prepared and designated as solution B. Solution B was added to solution B and stirred for 1 hour. The solution was then placed in the liner of a hydrothermal reactor, and the reactor was placed in an oven at 110°C for 48 hours. After the reaction was completed, the resulting suspension was placed in a centrifuge, and the supernatant was discarded. DMF was added for washing, and the centrifugation operation was repeated 3 times. The solution was then washed with acetone, and the sample was dried in an oven at 100°C for 8 hours to obtain UiO-66.

[0048] The preparation method of UiO-66 is the same as that of amino-functionalized UiO-66, except that solution B is 0.3M terephthalic acid / DMF.

[0049] The preparation methods of amino-functionalized MIL-101 and amino-functionalized MOF-5 are similar to those described above. In the specific implementation of this invention, the metal ion of amino-functionalized MIL-101 is Cr. 3+ The metal center of amino-functionalized MOF-5 is Zn. 2+ .

[0050] The preparation method of amino-functionalized ZIF-8 includes the following steps:

[0051] S1. Zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in deionized water to prepare a zinc nitrate solution; then, 2-methylimidazole was dissolved in another 160g of deionized water to prepare a 2-methylimidazole solution. Both solutions were vigorously stirred at room temperature, and the resulting colorless solution immediately turned milky white. After stirring for 20 minutes, the synthesized ZIF-8 particles were collected by centrifugation (9000 r / min, 10 min) and washed three times with deionized water.

[0052] S2. The synthesized ZIF-8 particles were dried at 50 °C for 12 hours and then activated under vacuum at 150 °C for 1 hour. They were then placed in saturated vapor of ethylenediamine (EDA) for 3 hours, followed by the addition of 25% EDA aqueous solution and reaction at 117 °C for 2 hours. Afterwards, the amination-modified ZIF particles were collected by centrifugation (9000 r / min, 10 min), washed three times with deionized water, and completely dried in a vacuum oven at 50 °C for 12 hours.

[0053] The preparation method of protonated MOFs includes the following steps:

[0054] The prepared amination MOFs were placed in a 1M phosphoric acid solution and stirred at 60°C for 24 hours. After the reaction was complete, the desired solid was obtained by centrifugation, followed by washing the solid with ethanol until the washing solution was neutral. The washed sample was then vacuum dried at 60-80°C or air dried until the sample was completely dehydrated.

[0055] The preparation method of amino-functionalized MOFs composite heat stabilizers includes the following steps:

[0056] The raw material components are mixed evenly to obtain the amino-functionalized MOFs composite heat stabilizer.

[0057] The preparation method of PVC pipe material includes the following steps:

[0058] Each raw material component is added to a high-speed mixer and mixed evenly to obtain PVC pipe material.

[0059] The preparation method of PVC pipes includes the following steps:

[0060] The obtained PVC pipe material is added to a screw extruder, and after melt extrusion and die shaping, PVC pipe material is obtained.

[0061] Example 1

[0062] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized protonated UiO-66, 20 parts of zinc stearate, and 10 parts of pentaerythritol.

[0063] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5 parts calcium carbonate, 8 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 3 parts MBS.

[0064] Example 2

[0065] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized protonated UiO-66, 25 parts of zinc stearate, and 10 parts of pentaerythritol.

[0066] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 8 parts calcium carbonate, 4 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 3 parts MBS.

[0067] Example 3

[0068] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized protonated MIL-101, 30 parts of zinc stearate, and 15 parts of pentaerythritol.

[0069] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 15 parts calcium carbonate, 4 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 2.5 parts MBS.

[0070] Example 4

[0071] The specific components and preparation method of an amino-functionalized MOFs composite heat stabilizer are the same as in Embodiment 1.

[0072] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5 parts calcium carbonate, 6 parts MOF composite heat stabilizer, 1.5 parts paraffin wax, and 2.5 parts MBS.

[0073] Example 5

[0074] The specific components and preparation method of an amino-functionalized MOFs composite heat stabilizer are the same as in Embodiment 2.

[0075] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5 parts calcium carbonate, 6 parts MOF composite heat stabilizer, 1.5 parts paraffin wax, and 3 parts MBS.

[0076] Example 6

[0077] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized protonated ZIF-8, 25 parts of zinc stearate, and 15 parts of pentaerythritol.

[0078] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5 parts calcium carbonate, 5 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 2.5 parts MBS.

[0079] Example 7

[0080] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized protonated MOF-5, 25 parts of zinc stearate, and 15 parts of pentaerythritol.

[0081] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5 parts calcium carbonate, 5 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 2.5 parts MBS.

[0082] Comparative Example 1

[0083] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized protonated UiO-66, 25 parts of zinc stearate, and 5 parts of pentaerythritol.

[0084] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 6 parts calcium carbonate, 4 parts MOF composite heat stabilizer, 1 part paraffin wax, and 3.5 parts MBS.

[0085] Comparative Example 2

[0086] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized protonated UiO-66, 5 parts of zinc stearate, and 12 parts of pentaerythritol.

[0087] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5 parts calcium carbonate, 5 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 2.5 parts MBS.

[0088] Comparative Example 3

[0089] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized protonated UiO-66, 40 parts of zinc stearate, and 10 parts of pentaerythritol.

[0090] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 10 parts calcium carbonate, 6 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 3 parts MBS.

[0091] Comparative Example 4

[0092] An amino-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of amino-functionalized UiO-66, 25 parts of zinc stearate, and 10 parts of pentaerythritol.

[0093] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 10 parts calcium carbonate, 8 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 3 parts MBS.

[0094] Comparative Example 5

[0095] A heat stabilizer comprising the following components in parts by weight: 100 parts zinc stearate and 50 parts pentaerythritol.

[0096] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 10 parts calcium carbonate, 8 parts heat stabilizer, 2 parts paraffin wax, and 3 parts MBS.

[0097] Comparative Example 6

[0098] A proton-functionalized MOFs composite heat stabilizer comprises the following components in parts by weight: 100 parts of protonated UiO-66, 20 parts of zinc stearate, and 10 parts of pentaerythritol.

[0099] A PVC pipe material comprises the following components in parts by weight: 100 parts polyvinyl chloride, 10 parts calcium carbonate, 5 parts MOF composite heat stabilizer, 2 parts paraffin wax, and 3 parts MBS.

[0100] Performance testing

[0101] The heat stability time of the PVC pipe materials in the examples and comparative examples was tested, and the specific methods are as follows:

[0102] (1) Torque rheometer test method: The torque rheometer is used to conduct rheological experiments on PVC pipe material. The test temperature is 185℃ and the rotation speed is 27rpm. Samples are taken at intervals and the color difference meter is used to observe the color change. The time it takes for the color to change from colorless to yellow is the thermal stability time.

[0103] (2) Congo Red Method: According to GB / T 2917.1-2002 Determination of the release of hydrogen chloride and any other acidic products at high temperature from blends and products mainly composed of vinyl chloride homopolymers and copolymers, Congo Red Method, the test temperature is 200℃. The HCl gas generated during the decomposition of PVC reacts with the Congo Red test paper, causing the test paper to change color. By measuring the time required for the test paper to change color, the thermal stability of PVC can be evaluated.

[0104] It should be noted that the two testing methods are based on different principles. The Congo red method mainly tests the hydrogen chloride produced by the decomposition of the material, while the torque rheometer tests the color of the actual sample. This color change is mainly due to the unsaturated double bonds generated by the decomposition of PVC, which cause the material to turn yellow.

[0105] Specific test results are as follows: Figure 1 As shown in Table 1:

[0106] Table 1. Results of Congo Red Method Test

[0107] Thermal stability time / min Example 1 51 Example 2 46 Example 3 47 Example 4 47 Example 5 49 Example 6 45 Example 7 46 Comparative Example 1 36 Comparative Example 2 31 Comparative Example 3 25 Comparative Example 4 40 Comparative Example 5 12 Comparative Example 6 15

[0108] Based on the results of torque rheometer testing and Congo red method testing, the composite heat stabilizer prepared in this invention has a thermal stability time of over 45 minutes, exhibiting excellent thermal stability. As shown in Example 2 and Comparative Example 4, the protonated amino groups on the ligands can react with hydrogen chloride, effectively improving the long-term thermal stability of PVC pipes. The test results of Comparative Example 4 and Example 2 show that the unprotonated MOFs exhibit good thermal stability, but there is still a certain gap compared to the protonated MOFs. This performance difference may be due to the different binding forces of the two materials to hydrogen chloride. Unprotonated MOFs fix hydrogen chloride through van der Waals forces, while protonated MOFs fix hydrogen chloride in the MOF pores through electrostatic attraction.

[0109] As can be seen from Example 1 and Comparative Example 5, the PVC material has poor thermal stability without amino-functionalized protonated MOFs in the heat stabilizer. This indicates that amino-functionalized protonated UiO-66 can significantly improve the thermal stability of PVC materials.

[0110] The test results of Example 2, Comparative Example 2 and Comparative Example 3 show that protonated UiO-66-NH2 can effectively absorb hydrogen chloride gas generated during PVC processing and improve the thermal stability of the material. However, excessive zinc stearate can lead to the side reaction of ZnCl2, which accelerates the decomposition of PVC. On the other hand, insufficient zinc stearate can lead to poor early thermal stability of the polymer. This indicates that zinc stearate has a significant impact on the initial thermal stability of the entire system. Therefore, it is necessary to control the proportion of zinc stearate in the composite heat stabilizer.

[0111] As can be seen from Comparative Example 6 and Example 2, protonation of MOFs alone did not improve the thermal stability of the system. This may be because the selected MOFs did not have suitable sites to supply protons, so the protonation effect was poor.

[0112] The test results of Comparative Example 1 and Example 2 show that a low pentaerythritol content will affect the thermal stability of PVC materials. This is because pentaerythritol can effectively complex ZnCl2 produced by the side reaction, reduce the free ZnCl2 in the system, and thus inhibit the decomposition of PVC materials.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An amino-functionalized MOFs composite heat stabilizer, characterized in that, The components include the following parts by weight: 100 parts of amino-functionalized protonated MOFs, 20-30 parts of zinc stearate, and 10-15 parts of polyol; The amino-functionalized protonated MOFs are at least one of amino-functionalized protonated UiO-66, MIL-101, MOF-5, and ZIF-8. The polyol is at least one of pentaerythritol, pentaerythritol distearate, and pentaerythritol monostearate.

2. The composite heat stabilizer according to claim 1, characterized in that, The amino functionalization includes replacing the organic ligands of UiO-66, MIL-101, or MOF-5 with organic ligands containing amino groups, or modifying ZIF-8 with organic amines.

3. The composite heat stabilizer according to claim 2, characterized in that, The amino-containing organic ligand is at least one of 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, and 2,3-diaminoterephthalic acid.

4. The composite heat stabilizer according to claim 2, characterized in that, The organic amine is at least one of ethylenediamine, 1,3-propanediamine, and 1,4-butanediamine.

5. The composite heat stabilizer according to claim 1, characterized in that, The acid used for protonation is at least one of phosphoric acid, formic acid, and acetic acid.

6. The composite heat stabilizer according to claim 1, characterized in that, The preparation method of the composite heat stabilizer includes the following steps: Amino-functionalized protonated MOFs, zinc stearate, and polyols are mixed evenly to obtain the amino-functionalized MOFs composite heat stabilizer.

7. The application of an amino-functionalized MOFs composite heat stabilizer as described in any one of claims 1 to 6 in the preparation of PVC materials.

8. A PVC pipe material, characterized in that, It comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5-15 parts inorganic filler, 3-8 parts composite heat stabilizer as described in any one of claims 1 to 6, 1-2 parts lubricant, and 1-5 parts processing aid; The processing aid is at least one of methyl methacrylate-butadiene-styrene copolymer, chlorinated polyethylene, and ethylene-octene copolymer.

9. A PVC pipe, characterized in that, The PVC pipe includes the PVC pipe material as described in claim 8.

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