High-thermal-stability PVC floor film and preparation method thereof

Abstract

The application discloses a high-thermal-stability PVC floor film and a preparation method thereof. The high-thermal-stability PVC floor film comprises the following components in parts by weight: 100-120 parts of polyvinyl chloride resin, 30-40 parts of a filler, 1-3 parts of a crosslinking agent, 2-3 parts of a main stabilizer and 0.5-1.5 parts of an auxiliary stabilizer. The main stabilizer is a metal organic framework surface growth modified hydrotalcite which is then subjected to surface modification. The PVC floor film prepared by the application has good thermal stability and is not prone to aging, and can still maintain good color and luster after long-time use.

Description

Technical Field

[0001] This application relates to the field of PVC films, and in particular to a high thermal stability PVC floor film and its preparation method. Background Technology

[0002] PVC flooring is a rapidly developing plastic decorative material in recent years, with advantages such as being lightweight, thin, highly elastic, and slip-resistant. However, due to the presence of unstable allyl chloride and tertiary chlorine atoms, double bonds, and polyene structures in the PVC molecule, PVC is prone to oxidative degradation, causing the flooring to yellow or blacken.

[0003] Currently, the thermal stability of PVC flooring membranes is improved by mixing them with stabilizers during the manufacturing process. Commonly used calcium-zinc stabilizers have advantages such as being non-toxic, harmless, environmentally friendly, and inexpensive. However, as calcium-zinc stabilizers replace allyl chloride and tertiary chlorine atoms, they easily form zinc chloride, which has a catalytic dechlorination effect, thereby accelerating the aging of the flooring membrane and resulting in a shorter service life for PVC flooring membranes. Summary of the Invention

[0004] To address the issues of poor thermal stability and short service life of PVC flooring membranes, this application provides a PVC flooring membrane with high thermal stability and its preparation method.

[0005] In a first aspect, a PVC flooring membrane, by weight, comprises the following components: 100-120 parts polyvinyl chloride resin, 30-40 parts filler, 1-3 parts crosslinking agent, 2-3 parts main stabilizer, and 0.5-1.5 parts auxiliary stabilizer; wherein the main stabilizer is obtained by growing hydrotalcite on the surface of a metal-organic framework and then performing surface modification.

[0006] By employing the above technical solutions, metal-organic frameworks (MOFs) can form complexes with PVC molecules, enhancing intermolecular forces and thus improving the thermal stability and mechanical properties of PVC flooring films. Furthermore, MOFs can capture hydrogen chloride and some reactive free radicals released during PVC degradation. The double-bonded groups on the MOFs can combine with the unsaturated groups generated during PVC dehydrochlorination, thereby reducing the catalytic effect of reactive free radicals and hydrogen chloride on the molecular chain dehydrochlorination, and minimizing further degradation and the formation of more unsaturated double bonds. This results in long-term thermal stability and improved mechanical properties for the flooring film. Since chloride ions in PVC molecules affect their dispersion performance, the MOFs, with their large specific surface area, can interact with PVC molecules to improve their dispersion. Additionally, the MOFs have a low crystal density, which, when blended with PVC molecules, lowers the glass transition temperature of PVC molecules, thereby increasing their plasticity.

[0007] Hydrotalcite is a type of layered compound assembled from positively charged main layers and interlayer anions through non-covalent interactions. It can also absorb hydrogen chloride produced by PVC degradation and improve the thermal stability of PVC flooring membranes by replacing chlorine atoms in PVC through anion intercalation in the layered structure. Furthermore, as an inorganic material with a layered structure, hydrotalcite can improve the mechanical properties of PVC flooring membranes, thereby expanding their application range.

[0008] This application employs the growth of hydrotalcite on the surface of a metal-organic framework (MOF). On one hand, because MOFs are formed by the complexation of inorganic and organic materials, their stability is poor, and they easily decompose and lose their effectiveness with increased use. Simultaneously, MOFs have poor mechanical properties, and their addition can negatively impact the mechanical properties of PVC flooring membranes. Growing hydrotalcite on the MOF can slow down the decomposition of the MOF, improve the stability of the main stabilizer, and extend the service life of the PVC flooring membrane. Furthermore, hydrotalcite can form a more complex three-dimensional layered structure on the surface of the MOF, improving both the mechanical properties and thermal stability of the PVC flooring membrane. On the other hand, due to the large number of active hydroxyl functional groups on the surface of hydrotalcite, internal hydrogen bonds are easily formed between hydrotalcite ions, resulting in an aggregation effect. This affects the dispersibility of hydrotalcite during the blending process with PVC. Moreover, the hydrophilic nature of the hydrotalcite surface leads to poor compatibility with PVC, further contributing to the easier aggregation of hydrotalcite during blending with PVC, thus reducing its effectiveness in improving the thermal stability and mechanical properties of PVC. By growing hydrotalcite on the surface of a metal-organic framework (MOF), which has a large specific surface area and can adsorb hydrotalcite, the dispersibility of hydrotalcite during the blending process and its compatibility with PVC molecules can be improved. This, in turn, enhances the compatibility of the main stabilizer with PVC resin and improves the thermal stability and mechanical properties of PVC flooring.

[0009] Preferably, the primary stabilizer comprises, by weight, the following components: 1-2 parts of a metal-organic framework, 10-15 parts of...

[0010] Calcium nitrate, 10-15 parts zinc nitrate, 22-42 parts hexamethylenetetramine, 5-12 parts organic acid, 0.5-2.5 parts sodium stearate.

[0011] By employing the above technical solutions, the hydrotalcite formed using calcium and zinc ions as cations exhibits longer thermal stability and lighter color, with zinc ions also contributing to a brightening effect, thus improving the quality of PVC flooring membranes. Furthermore, after calcium-zinc hydrotalcite grows on a metal-organic framework, the resulting primary stabilizer, auxiliary stabilizer, and filler synergistically enhance the thermal stability and mechanical properties of the PVC flooring membrane. Intercalation modification with organic acids allows the organic acid radicals and the metal-organic framework to bind with PVC molecules, synergistically improving the compatibility between hydrotalcite and PVC. Organic acid radicals also improve the thermal stability of the primary stabilizer, enabling it to significantly improve the thermal stability of the PVC flooring membrane even with a relatively low dosage. Excessive dosage of the primary stabilizer can lead to poor dispersibility, thereby affecting the mechanical properties of the PVC flooring membrane; therefore, the intercalation modification with organic acids indirectly improves the mechanical properties of the PVC flooring membrane. The introduction of sodium stearate as a component, synergistically with the metal-organic framework, improves the dispersibility and compatibility of the hydrotalcite and enhances the plasticity of the PVC flooring membrane.

[0012] Preferably, the main stabilizer is prepared by the following steps:

[0013] Growth of hydrotalcite: Calcium nitrate, zinc nitrate and hexamethylenetetramine are mixed, and then a metal-organic framework and an organic acid are added to react and obtain metal-organic framework-hydrotalcite.

[0014] Surface modification: Mix metal-organic framework-hydrotalcite with ethanol solution, add sodium stearate and mix, stir at 85-95℃ for 20-60 min to obtain the main stabilizer.

[0015] Typical but not limiting steps for hydrotalcite growth, with a reaction temperature of 100-110℃ and a reaction time of 7-9h.

[0016] By employing the above technical solution, calcium-zinc hydrotalcite is first grown on the surface of a metal-organic framework (MOF), allowing for better dispersion of the hydrotalcite on the MOF surface. Then, sodium stearate is used for coating modification, resulting in a primary stabilizer with better compatibility with PVC. Furthermore, by optimizing the preparation method parameters, the resulting PVC floor membrane exhibits better and longer-lasting thermal stability, as well as improved mechanical properties.

[0017] Preferably, the organic acid is one of sodium cinnamate and sodium sorbate.

[0018] By adopting the above technical solutions, cinnamic acid-intercalated hydrotalcite can absorb the active free radicals generated by PVC degradation. Together with the metal-organic framework, it can synergistically reduce the catalytic degradation effect of active free radicals on the PVC membrane, thus significantly improving the long-term thermal stability of the PVC flooring membrane. Furthermore, cinnamic acid-intercalated hydrotalcite also possesses ultraviolet absorption properties, which can reduce aging caused by light exposure and maintain the mechanical properties of the PVC flooring membrane. Similarly, sodium sorbate-intercalated hydrotalcite can absorb the active free radicals generated by PVC degradation. Together with the metal-organic framework, it can synergistically reduce the catalytic degradation effect of active free radicals on the PVC membrane, thus significantly improving the long-term thermal stability of the PVC flooring membrane. In addition, the unsaturated structure in the sorbate group can cross-link with the unsaturated double bond segments generated by the dehydrochlorination of PVC, thereby reducing chain segment decomposition and maintaining the mechanical properties of the PVC flooring membrane.

[0019] Preferably, the metal-organic framework is a metal-organic framework containing rare earth elements, and the raw materials of the metal-organic framework include the following components in parts by weight: 10-20 parts of trimesic acid, 5-8 parts of cerium nitrate, and 7-10 parts of zinc nitrate.

[0020] By adopting the above technical solution, the cerium ions in cerium nitrate are trivalent, which can combine with active free radicals to form tetravalent cerium, thereby reducing the catalytic effect of active free radicals on the dehydrochlorination of PVC and improving the thermal stability of PVC. In addition, the bimetallic organic framework formed by cerium ions and zinc ions has better structural stability and can further form stable complexes with zinc chloride, reducing the occurrence of "zinc burning". After growing hydrotalcite on the surface and modifying it with sodium stearate, the bimetallic organic framework can synergistically improve the thermal stability and plasticity of PVC flooring film while maintaining good mechanical properties.

[0021] Preferably, the metal-organic framework is prepared using the following steps:

[0022] Trimethylbenzene acid, cerium nitrate, and zinc nitrate were ball-milled, and the resulting product was subjected to microwave reaction to obtain a metal-organic framework.

[0023] Typical, but not limiting, ball milling time is 1-2 hours, ball-to-material ratio is 50:1, and microwave reaction time is 20-40 minutes.

[0024] By adopting the above technical solution, the bimetallic organic framework is prepared by ball milling combined with microwave method. It has the advantages of short synthesis time and environmental protection. In particular, when microwave and ball milling are carried out simultaneously, the interfacial energy and reactivity of the reactants can be improved, the effect of the metal-organic framework can be improved, the synergistic effect of the metal-organic framework and other components can be improved, and thus the thermal stability and mechanical properties of PVC can be improved.

[0025] Preferably, the auxiliary stabilizer is a polyol ester.

[0026] By adopting the above technical solution, polyol esters can absorb the released hydrogen chloride and slow down PVC degradation. When the metal-organic framework-hydrotalcite is used as the main stabilizer, the polyol esters re-complex the generated metal chlorides, improving the long-term thermal stability of the PVC flooring film.

[0027] Preferably, the filler is diatomaceous earth.

[0028] By adopting the above technical solution, diatomaceous earth, as a filler, can fill the pores formed during the preparation of PVC flooring membrane, thereby improving the mechanical properties of PVC flooring membrane. Furthermore, when the main stabilizer is metal-organic framework-hydrotalcite, the metal impurities in diatomaceous earth can form complexes with the metal-organic framework, expanding the surface porosity and specific surface area of ​​diatomaceous earth, improving the bonding between diatomaceous earth and PVC, facilitating the dispersion of diatomaceous earth in PVC flooring membrane, and improving the thermal stability and mechanical properties of PVC flooring membrane.

[0029] Preferably, the crosslinking agent is a silane coupling agent.

[0030] Typically, but not limitingly, the silane coupling agent used is one of KH560 or KH570.

[0031] By adopting the above technical solution, silane coupling agents can improve the compatibility between metal-organic framework-hydrotalcite and PVC, and enable the filler to crosslink with polyvinyl chloride resin, thereby improving the modification effect of PVC flooring membrane and enhancing the thermal stability and mechanical properties of PVC flooring membrane.

[0032] In summary, this application has the following beneficial effects:

[0033] 1. A primary stabilizer obtained by growing hydrotalcite on the surface of a bimetallic organic framework and modifying it with stearate can improve the thermal stability and mechanical properties of PVC, and also absorb hydrogen chloride released during the use of PVC flooring film, thereby slowing down the degradation and discoloration of PVC and improving the service life of PVC flooring film. Detailed Implementation

[0034] The raw materials used in the examples and preparation examples are all commercially available and described in detail below. The present application will be further described in detail below with reference to the examples.

[0035] Preparation of metal-organic frameworks

[0036] Preparation Example 1-1: A metal-organic framework was prepared using the following steps:

[0037] 15g of pyromellitic acid, 6.5g of cerium nitrate, 8.5g of zinc nitrate and 1L of water were mixed to obtain a mixed solution. 1500g of stainless steel balls were used to ball mill the mixed solution for 1.5h. After ball milling, the solution was taken out and microwaved for 30min. After filtration, washing and drying, an organometallic framework was obtained.

[0038] Preparation Examples 1-2: A metal-organic framework was prepared using the following steps:

[0039] Take 20g of pyromellitic acid, 8g of cerium nitrate, 10g of zinc nitrate and 1L of water to mix to obtain a mixed solution. Take 1900g of stainless steel balls to ball mill the mixed solution for 2h. After ball milling, take it out and microwave it for 40min. Filter, wash and dry to obtain organometallic framework.

[0040] Preparation Examples 1-3: A metal-organic framework was prepared using the following steps:

[0041] Take 10g of pyromellitic acid, 5g of cerium nitrate, 7g of zinc nitrate and 1L of water to mix to obtain a mixed solution. Take 1100g of stainless steel balls to ball mill the mixed solution for 1 hour. After ball milling, take it out and microwave it for 20 minutes. Filter, wash and dry to obtain an organometallic framework.

[0042] Preparation Examples 1-4, a metal-organic framework, differ from Preparation Example 1-1 in that cerium nitrate is replaced with an equal amount of calcium nitrate.

[0043] Preparation Examples 1-5: A metal-organic framework was prepared by the following steps: 15g of trimesic acid, 6.5g of cerium nitrate, 8.5g of zinc nitrate and 1L of water were mixed to obtain a mixed solution. 1500g of stainless steel balls were used to ball mill the mixed solution for 1.5h. After ball milling, the mixture was removed, filtered, washed and dried to obtain the metal-organic framework.

[0044] Preparation Examples 1-6: A metal-organic framework was prepared by the following steps: 15g of pyromellitic acid, 6.5g of cerium nitrate, 8.5g of zinc nitrate and 1L of water were mixed to obtain a mixed solution. The mixed solution was subjected to microwave reaction for 30min, filtered, washed and dried to obtain the metal-organic framework.

[0045] Preparation of the main stabilizer

[0046] Preparation Example 2-1, a primary stabilizer, was prepared by the following steps:

[0047] Growth of hydrotalcite: 13g calcium nitrate, 13g zinc nitrate and 32g hexamethylenetetramine were mixed, and then 1.5g metal-organic framework and 8.5g sodium sorbate were added. The mixture was reacted at 105℃ for 8h to obtain metal-organic framework-hydrotalcite.

[0048] Surface modification: Take metal-organic framework-hydrotalcite and mix with 1L ethanol solution (water and ethanol volume ratio 1:1), add 1.5g sodium stearate and mix, stir at 90℃ for 40min, and dry to obtain the main stabilizer.

[0049] The metal-organic framework was derived from Preparation Example 1-1.

[0050] Preparation Example 2-2, a primary stabilizer, was prepared by the following steps:

[0051] Growth of hydrotalcite: 10g calcium nitrate, 10g zinc nitrate and 22g hexamethylenetetramine were mixed, then 1g metal-organic framework and 5g sodium sorbate were added, and the mixture was reacted at 100℃ for 7h to obtain metal-organic framework-hydrotalcite.

[0052] Surface modification: Take metal-organic framework-hydrotalcite and mix with 1L ethanol solution (water and ethanol volume ratio 1:1), add 0.5g sodium stearate and mix, stir at 85℃ for 20min, and dry to obtain the main stabilizer.

[0053] The metal-organic framework was derived from preparation examples 1-2.

[0054] Preparation Example 2-3, a primary stabilizer, was prepared by the following steps:

[0055] Growth of hydrotalcite: 15g calcium nitrate, 15g zinc nitrate and 42g hexamethylenetetramine were mixed, then 2g metal-organic framework and 12g sodium sorbate were added, and the mixture was reacted at 110℃ for 9h to obtain metal-organic framework-hydrotalcite.

[0056] Surface modification: Take metal-organic framework-hydrotalcite and mix with 1L ethanol solution (water and ethanol volume ratio 1:1), add 2.5g sodium stearate and mix, stir at 95℃ for 60min, and dry to obtain the main stabilizer.

[0057] The metal-organic frameworks were derived from preparation examples 1-3.

[0058] Preparation Example 2-4, a primary stabilizer, differs from Preparation Example 2-1 in that the metal-organic framework is derived from Preparation Example 1-4.

[0059] Preparation Example 2-5, a primary stabilizer, differs from Preparation Example 2-1 in that the metal-organic framework is derived from Preparation Example 1-5.

[0060] Preparation Examples 2-6, a primary stabilizer, differ from Preparation Example 2-1 in that the metal-organic framework is derived from Preparation Examples 1-6.

[0061] Preparation Example 2-7, a primary stabilizer, differs from Preparation Example 2-1 in that the organic acid used is sodium cinnamate.

[0062] Preparation Example 2-8, a primary stabilizer, differs from Preparation Example 2-1 in that the organic acid used is citric acid.

[0063] Preparation Examples 2-9: A primary stabilizer, prepared using the following steps.

[0064] Growth of hydrotalcite: 6g calcium nitrate, 20g zinc nitrate and 32g hexamethylenetetramine were mixed, and then 3g metal-organic framework and 8.5g sodium sorbate were added. The mixture was reacted at 105℃ for 8h to obtain metal-organic framework-hydrotalcite.

[0065] Surface modification: Take metal-organic framework-hydrotalcite and mix with 1L ethanol solution (water and ethanol volume ratio 1:1), add 1.5g sodium stearate and mix, stir at 90℃ for 40min, and dry to obtain the main stabilizer.

[0066] The metal-organic framework was derived from Preparation Example 1-1.

[0067] Preparation Example 2-10: A primary stabilizer was prepared using the following method.

[0068] Growth of hydrotalcite: 13g calcium nitrate, 13g zinc nitrate and 32g hexamethylenetetramine were mixed, and then 10g sodium sorbate was added. The mixture was reacted at 105℃ for 8 hours to obtain hydrotalcite.

[0069] Surface modification: Take hydrotalcite and add 1L of ethanol solution (water and ethanol volume ratio 1:1), mix, add 1.5g of sodium stearate and mix, stir at 90℃ for 40min, and dry to obtain the main stabilizer.

[0070] Preparation Example 2-11, a primary stabilizer, was prepared by the following method,

[0071] Growth of hydrotalcite: Mix 13g calcium nitrate, 13g zinc nitrate and 32g hexamethylenetetramine, then add 10g sodium sorbate and react at 105℃ for 8h to obtain the main stabilizer;

[0072] Preparation Example 2-12, a primary stabilizer, was prepared by the following method,

[0073] Take a metal-organic framework and add 1L of ethanol solution (water and ethanol volume ratio 1:1), mix, add 1.5g of sodium stearate and mix, stir at 90℃ for 40min, and dry to obtain the main stabilizer.

[0074] The metal-organic framework was derived from Preparation Example 1-1.

[0075] Example

[0076] Example 1: A high thermal stability PVC floor membrane is prepared using the following steps:

[0077] S1. Take 110g of polyvinyl chloride resin, 35g of diatomaceous earth, 2g of KH560, 2.5g of main stabilizer and 1g of auxiliary stabilizer, mix them, stir and disperse to obtain expanded powder;

[0078] S2. Take the expanded powder and melt-extrude it to obtain the rubber compound;

[0079] S3. The rubber compound is calendered into sheets and stretched to obtain PVC flooring film.

[0080] The main stabilizer was derived from Preparation Example 2-1, and the auxiliary stabilizer was bispentaerythritol ester.

[0081] Example 2: A high thermal stability PVC floor membrane is prepared using the following steps:

[0082] S1. Take 120g of polyvinyl chloride resin, 30g of diatomaceous earth, 1g of KH560, 3g of main stabilizer and 1.5g of auxiliary stabilizer, mix them, stir and disperse to obtain expanded powder;

[0083] S2. Take the expanded powder and melt-extrude it to obtain the rubber compound;

[0084] S3. The rubber compound is calendered into sheets and stretched to obtain PVC flooring film.

[0085] The main stabilizer was derived from Preparation Example 2-2, and the auxiliary stabilizer was dipentaerythritol ester.

[0086] Example 3: A high thermal stability PVC floor membrane, prepared using the following steps:

[0087] S1. Take 100g of polyvinyl chloride resin, 40g of diatomaceous earth, 3g of KH560, 2g of main stabilizer and 0.5g of auxiliary stabilizer, mix them, stir and disperse to obtain expanded powder;

[0088] S2. Take the expanded powder and melt-extrude it to obtain the rubber compound;

[0089] S3. The rubber compound is calendered into sheets and stretched to obtain PVC flooring film.

[0090] The main stabilizer was derived from Preparation Examples 2-3, and the auxiliary stabilizer was dipentaerythritol ester.

[0091] Example 4, a high thermal stability PVC flooring film, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-4.

[0092] Example 5, a high thermal stability PVC flooring membrane, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-5.

[0093] Example 6, a high thermal stability PVC flooring membrane, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-6.

[0094] Example 7, a high thermal stability PVC flooring film, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-7.

[0095] Example 8, a high thermal stability PVC flooring membrane, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-8.

[0096] Example 9, a high thermal stability PVC flooring membrane, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-9.

[0097] Example 10, a high thermal stability PVC flooring membrane, differs from Example 1 in that diatomaceous earth is replaced with an equal amount of wood flour.

[0098] Comparative Example

[0099] Comparative Example 1, a PVC flooring film, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-10.

[0100] Comparative Example 2, a PVC flooring film, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-11.

[0101] Comparative Example 3, a PVC flooring film, differs from Example 1 in that the main stabilizer is derived from Preparation Examples 2-12.

[0102] Comparative Example 4, a PVC flooring film, differs from Example 1 in that the auxiliary stabilizer is replaced with an equal amount of the main stabilizer.

[0103] Comparative Example 5, a PVC flooring film, was prepared using the following steps:

[0104] S1. Take 110g of polyvinyl chloride resin, 35g of diatomaceous earth, 2g of KH560, 6g of main stabilizer and 2g of auxiliary stabilizer, mix them, stir and disperse to obtain expanded powder;

[0105] S2. Take the expanded powder and melt-extrude it to obtain the rubber compound;

[0106] S3. The rubber compound is calendered into sheets and stretched to obtain PVC flooring film.

[0107] The main stabilizer was derived from Preparation Example 2-1, and the auxiliary stabilizer was bispentaerythritol ester.

[0108] Comparative Example 6, a PVC flooring film, was prepared using the following steps:

[0109] Take 1000g of PVC, 4g of heat stabilizer, and 35 parts of DOP and mix them on a high-speed mixer. Then pour the mixture into a two-roll mill with a set temperature of 180℃ and a roller gap of 3mm for plasticizing and mixing for 5 minutes to make PVC sheets. Stretch the sheets to obtain PVC flooring film.

[0110] A heat stabilizer was prepared by mixing 16g of lanthanum 2-benzoylbenzoate and 4g of zinc stearate at high speed for 5 minutes.

[0111] Lanthanum 2-benzoylbenzoate was prepared by the following steps.

[0112] (1) Place 13.56 g of 2-benzoylbenzoic acid in a beaker containing 200 mL of anhydrous ethanol solution and stir at a constant speed of 400 r / min to completely dissolve it, and prepare a 0.2 g / mL solution 1.

[0113] (2) Measure 14.8 mL of 1.356 mol / L lanthanum nitrate solution into a beaker according to the molar ratio of lanthanum nitrate: 2-benzoylcarboxylic acid = 1:3. Heat the solution to remove water, and then add anhydrous ethanol solution to prepare 0.2 g / mL solution 2 for later use.

[0114] (3) 60 mL of 1 mol / L sodium hydroxide ethanol solution was slowly added to solution 1 under water bath and stirring conditions, and a white flocculent intermediate product appeared. After stirring for 30 min, solution 2 was slowly added to it, and the white flocculent product disappeared. After stirring for 6 h, the solution was filtered, the filtrate was evaporated and concentrated, cooled and crystallized, washed and dried to obtain lanthanum 2-benzoylbenzoate.

[0115] Performance testing

[0116] The PVC flooring films prepared in Examples 1-10 and Comparative Examples 1-6 were subjected to performance tests. The tests were performed in parallel for 6 times, and the average value was taken.

[0117] Experiment 1: Thermal stability test: The test was conducted according to GB / T 9349-2002. A PVC film with a thickness of approximately 1 mm was cut into 1 cm pieces. 2 A cube was placed on an aluminum sheet and heated at a constant temperature of 190℃ in a thermal aging oven. The color was observed to evaluate thermal stability. The color of the test piece is expressed numerically, and the relationship is shown in Table 1. The test results are shown in Table 2.

[0118] Experiment 2: Mechanical property test: The test was conducted according to GB / T1040-2006 "Determination of tensile properties of plastics". The test results are shown in Table 2.

[0119] Table 1: Color Values ​​of Test Pieces

[0120] color colorless light yellow yellow orange color Orange-red black numerical values 0 1 2 3 4 5

[0121] Table 1: Performance test results of Examples 1-10 and Comparative Examples 1-6

[0122]

[0123] As can be seen from Examples 1-6 and Table 2, both the preparation method and raw materials of the metal-organic framework (MOF) have a certain impact on the effect of the main stabilizer. This is because, after introducing cerium into the MOF, the cerium ions in cerium nitrate are trivalent, which can combine with active free radicals to form tetravalent cerium, thereby reducing the further catalysis of PVC dehydrochlorination by active free radicals and improving the thermal stability of PVC. In addition, the bimetallic organic framework formed by cerium ions and zinc ions has better stability and can further form stable complexes with zinc chloride, reducing the occurrence of "zinc burning". The preparation of bimetallic organic frameworks using a combination of ball milling and microwave method has the advantages of short synthesis time and environmental friendliness. In particular, when microwave and ball milling are carried out simultaneously, the interfacial energy and reactivity of the reactants can be improved, enhancing the effect of the MOF and the synergistic effect between the MOF and other components, thereby improving the thermal stability and mechanical properties of PVC.

[0124] Based on Examples 1 and 7-8, and referring to Table 2, it can be seen that when sodium cinnamate and sodium sorbate are used as organic acids, the main stabilizer is more effective. This is because the cinnamate-intercalated hydrotalcite can absorb the active free radicals generated by PVC degradation. Together with the metal-organic framework, it can synergistically reduce the catalytic degradation effect of active free radicals on the PVC membrane, thus significantly improving the long-term thermal stability of the PVC flooring membrane. Furthermore, the cinnamate-intercalated hydrotalcite also has UV absorption properties, which can reduce aging caused by light exposure and maintain the mechanical properties of the PVC flooring membrane. Similarly, the sodium sorbate-intercalated hydrotalcite can absorb the active free radicals generated by PVC degradation. Together with the metal-organic framework, it can synergistically reduce the catalytic degradation effect of active free radicals on the PVC membrane, thus significantly improving the long-term thermal stability of the PVC flooring membrane. In addition, the sorbate group contains an unsaturated structure, which can cross-link with the unsaturated double bond segments generated by the dehydrochlorination of PVC, thereby reducing chain decomposition and maintaining the mechanical properties of the PVC flooring membrane.

[0125] Based on Examples 1, 9-10, and Comparative Examples 4-5, and referring to Table 2, it can be seen that the selection of PVC flooring components, their proportions, and the choice of components during the preparation of the main stabilizer affect the performance of the high-thermal-stability PVC flooring. This is because, among the components of the PVC flooring, dipentaerythritol ester, when the main stabilizer is a surface-modified metal-organic framework—hydrotalcite—can improve the compatibility between the main stabilizer and PVC, and synergistically absorb the released hydrogen chloride to enhance the stability of the PVC flooring. Compared to wood flour, diatomaceous earth, with its structure and properties, can provide better mechanical properties and thermal stability in synergy with the main stabilizer. Further optimization of the raw material proportions for the preparation of the main stabilizer can improve the effectiveness of the main stabilizer itself and its compatibility with other PVC flooring components.

[0126] Based on Example 1, Comparative Examples 1-3, and Table 2, it can be seen that when metal-organic frameworks, hydrotalcite, or modified hydrotalcite are used alone as the main stabilizers, the thermal stability and mechanical properties of the PVC floor membrane all decrease. This is because, on the one hand, since metal-organic frameworks are formed by the complexation of inorganic and organic materials, their stability is poor, and they easily decompose and lose their effectiveness with increased use. Simultaneously, the mechanical properties of metal-organic frameworks are poor, and their addition will affect the mechanical properties of the PVC floor membrane. By growing hydrotalcite into the metal-organic framework, the decomposition of the metal-organic framework can be slowed down, improving the stability of the main stabilizer and extending the service life of the PVC floor membrane. Furthermore, hydrotalcite can form a more complex three-dimensional layered structure on the surface of the metal-organic framework, which can improve the mechanical properties of the PVC floor membrane while also enhancing its thermal stability. On the other hand, due to the large number of active hydroxyl functional groups on its surface, hydrotalcite is prone to forming internal hydrogen bonds between hydrotalcite ions, resulting in an aggregation effect. This affects the dispersibility of hydrotalcite during the blending process with PVC. Furthermore, the hydrophilic nature of hydrotalcite leads to poor compatibility with the lipophilic PVC, further contributing to its agglomeration during blending and reducing its effectiveness in improving the thermal stability and mechanical properties of PVC. By growing hydrotalcite on the surface of a metal-organic framework (MOF), which has a large specific surface area and can adsorb hydrotalcite, and possesses good lipophilicity, the dispersibility of hydrotalcite during blending and its compatibility with PVC molecules are improved. This enhances the compatibility of the main stabilizer with PVC resin and improves the thermal stability and mechanical properties of the PVC flooring membrane.

[0127] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high thermal stability PVC floor membrane, characterized in that, Based on parts by weight, it includes the following components: 100-120 parts polyvinyl chloride resin, 30-40 parts filler, 1-3 parts crosslinking agent, 2-3 parts main stabilizer, and 0.5-1.5 parts auxiliary stabilizer; the crosslinking agent is a silane coupling agent; The main stabilizer is obtained by growing hydrotalcite on the surface of a metal-organic framework and then modifying the surface. The main stabilizer, by weight, comprises the following components: 1-2 parts metal-organic framework, 10-15 parts calcium nitrate, 10-15 parts zinc nitrate, 22-42 parts hexamethylenetetramine, 5-12 parts organic acid, and 0.5-2.5 parts sodium stearate. The main stabilizer is prepared by the following steps: Growth of hydrotalcite: Calcium nitrate, zinc nitrate and hexamethylenetetramine are mixed, and then a metal-organic framework and an organic acid are added to react and obtain metal-organic framework-hydrotalcite. Surface modification: Mix metal-organic framework-hydrotalcite with ethanol solution, add sodium stearate and mix, stir at 85-95℃ for 20-60 min to obtain the main stabilizer; The organic acid is one of sodium cinnamate and sodium sorbate; The metal-organic framework is a metal-organic framework containing rare earth elements. The raw materials of the metal-organic framework include the following components in parts by weight: 10-20 parts of trimesic acid, 5-8 parts of cerium nitrate, and 7-10 parts of zinc nitrate. The metal-organic framework is prepared using the following steps: Trimethylbenzene acid, cerium nitrate, and zinc nitrate were ball-milled, and the resulting product was subjected to microwave reaction to obtain a metal-organic framework.

2. The high thermal stability PVC floor membrane according to claim 1, characterized in that, The auxiliary stabilizer is a polyol ester.

3. The high thermal stability PVC floor membrane according to claim 1, characterized in that, The filler material is diatomaceous earth.

4. A method for preparing a high thermal stability PVC floor membrane according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Mix polyvinyl chloride resin, filler, crosslinking agent, main stabilizer and auxiliary stabilizer to obtain expanded powder; S2. Take the expanded powder and melt-extrude it to obtain the rubber compound; S3. Take the rubber material, calender it into a sheet, and stretch it to obtain PVC floor film.

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