A tung oil source PVC auxiliary heat stabilizer, its preparation method and application

Abstract

A tung oil-derived PVC auxiliary heat stabilizer, its preparation method, and application are disclosed. Tung oil anhydride and tung maleic anhydride are first subjected to a ring-opening addition reaction with phenylhydrazine, followed by dehydration and cyclization with acetic anhydride to produce modified tung maleic anhydride and tung maleic anhydride (BJT and BJTO) containing an N-maleimide structure. Both can be used as auxiliary heat stabilizers for PVC. The invention utilizes tung oil derivatives—tung oil anhydride and tung maleic anhydride—as raw materials. The resulting tung oil-derived PVC auxiliary heat stabilizers (BJT and BJTO) exhibit good compatibility with polyvinyl chloride resins, delay the "zinc burn" of traditional calcium / zinc heat stabilizers, and exhibit a good synergistic stabilization effect with traditional calcium stearate / zinc heat stabilizers, providing a viable solution to the "zinc burn" phenomenon associated with existing traditional calcium / zinc heat stabilizers.

Description

Technical Field

[0001] The invention belongs to the field of plastic additives, and particularly relates to a tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure, a preparation method and an application thereof. Background Art

[0002] Polyvinyl chloride (PVC) is the world's third most common plastic. Its low price makes it widely used in applications ranging from building decoration to everyday toys. However, when heated to 100°C, PVC undergoes a HCl-removal reaction, accelerating its degradation within its processing temperature (170-200°C). As degradation progresses, the color of the PVC resin darkens, and the mechanical properties of the finished product are severely damaged. Therefore, heat stabilizers are added during PVC processing to absorb the HCl released during PVC degradation and improve its thermal stability.

[0003] Currently, the main PVC heat stabilizers on the market include lead stabilizers, calcium / zinc composite heat stabilizers, organotin heat stabilizers, and metal-free organic heat stabilizers. In comparison, calcium / zinc composite heat stabilizers and metal-free organic heat stabilizers offer greater development potential. Both avoid the serious toxicity issues posed by heavy metal salts such as lead, barium, and cadmium to humans and the environment, and they also avoid the odor issues associated with organotin-based heat stabilizers. However, traditional calcium / zinc heat stabilizers have poor thermal stability and are prone to zinc burn in finished products. This can lead to yellowing (low thermal stability), insufficient whiteness (initial colorability issues), and poor lightfastness (low thermal stability) during PVC profile processing. Therefore, their use is limited in applications requiring high-performance products. Metal-free organic heat stabilizers offer excellent compatibility with polymer materials and contain no heavy metals. Their own stabilization effect is minimal or non-existent, but they exhibit excellent synergistic effects when used with other heat stabilizers.

[0004] With the increasing severity of energy shortages and environmental pollution worldwide, the development and utilization of renewable biomass resources has become particularly urgent. Tung oil anhydride and tung maleic anhydride are the main derivatives of tung oil, a specialty oil in my country. The present invention uses tung oil anhydride and tung maleic anhydride as starting materials to develop a "tung oil-derived PVC auxiliary heat stabilizer product containing an N-maleimide structure" that can effectively improve the thermal stability of general-purpose calcium zinc stearate composite heat stabilizers, in order to address the current situation of poor thermal stability of polyvinyl chloride and the poor thermal stability performance of traditional calcium / zinc heat stabilizers. The present invention has important scientific significance in terms of both resource selection and material performance. Summary of the Invention

[0005] Technical problem to be solved: To address the current situation in which PVC products treated with traditional calcium / zinc heat stabilizers on the market have poor thermal stability, the present invention uses tung oil anhydride and tung maleic anhydride, the main derivatives of tung oil, a specialty oil in my country, as raw materials to provide a tung oil-derived PVC auxiliary heat stabilizer, as well as its preparation method and application. This product has the advantage of delaying the "zinc burn" of traditional calcium / zinc heat stabilizers.

[0006] Technical solution: A preparation method for a tung oil-derived PVC auxiliary heat stabilizer, comprising the following steps: dissolving 35-40 g of anhydride in 200 mL of acetic acid according to proportion, wherein the anhydride is tung maleic anhydride or tung oil anhydride; adding 9-11 g of phenylhydrazine after complete dissolution; reacting at 35° C.-45° C. under closed conditions for 24-30 hours; removing the acetic acid in the reaction system by vacuum distillation to prepare an adduct of phenylhydrazine and the anhydride; then dissolving the adduct of phenylhydrazine and the anhydride in 200 mL of acetic anhydride; and reacting the system in a closed state for 12-16 hours at room temperature; and subsequently removing the acetic anhydride by vacuum distillation to obtain a tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure.

[0007] Preferably, according to proportion, 35 to 40 g of anhydride is dissolved in 200 mL of acetic acid, wherein the anhydride is tung oil anhydride or tung maleic anhydride. After complete dissolution, 9 to 11 g of phenylhydrazine is added, and the mixture is reacted at 35° C. under closed conditions for 24 hours. The acetic acid in the reaction system is distilled off by reduced pressure to prepare an adduct of phenylhydrazine and anhydride; the adduct of phenylhydrazine and anhydride is then dissolved in 200 mL of acetic anhydride, and the system is kept in a closed state for reaction for 12 hours at room temperature; the acetic anhydride is then distilled off by reduced pressure to obtain a tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure.

[0008] The tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure is prepared by the above preparation method.

[0009] The above-mentioned tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure is characterized by having the following structure:

[0010]

[0011] Application of the above BJT or BJTO in the preparation of thermal stabilizers.

[0012] Beneficial Effects: ① Leveraging the molecular properties of tung oil, a novel tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure was designed and synthesized. The N-maleimide structure in this molecule effectively improves the thermal stability of PVC products. This product delays the "zinc burn" of traditional calcium / zinc heat stabilizers and exhibits a synergistic stabilization effect with traditional calcium / zinc stearate heat stabilizers, providing a viable solution to the "zinc burn" phenomenon associated with existing calcium / zinc heat stabilizers. ② Using derivatives of tung oil, a specialty oil in my country, as raw materials to produce high-quality PVC auxiliary heat stabilizers promotes the high-value-added utilization of green, renewable resources and complies with the requirements of environmental protection and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The infrared spectra of tung oil anhydride (TOMA), tung oil anhydride (TMA), modified tung oil anhydride and tung oil anhydride (BJT and BJTO) containing N-maleimide structure are shown.

[0014] Figure 2 It is a product of tung oil anhydride (TMA), tung oil anhydride (TOMA), modified tung oil anhydride and tung oil anhydride containing N-maleimide structure (BJT and BJTO) 1 H-NMR spectrum;

[0015] Figure 3 This is an analysis chart of the thermal stability performance of PVC heat stabilizers in the experimental group and the control group. DETAILED DESCRIPTION

[0016] The parts not mentioned in the text are the same as the existing technology or can be implemented by using the existing technology. The following are the preferred embodiments of the present invention, but the present invention is not limited to the following embodiments. Slight improvements on the embodiments will also be considered as the protection scope of the present invention.

[0017] Example 1

[0018] Preparation of BJT: 39 g of TMA was dissolved in 200 mL of acetic acid, and 10.8 g of phenylhydrazine was added. The mixture was reacted at 35 °C for 24 h. The acetic acid was removed by vacuum distillation. The mixture was then dissolved in 200 mL of acetic anhydride and dehydrated for 12 h. Finally, the generated acetic acid and acetic anhydride were removed by vacuum distillation to obtain BJT.

[0019] Preparation of BJTO: 28.9 g of TOMA was dissolved in 200 mL of acetic acid, and 10.8 g of phenylhydrazine was added. The mixture was reacted at 35°C for 24 h. The acetic acid was removed by vacuum distillation. The mixture was then dissolved in 200 mL of acetic anhydride and dehydrated for 12 h. Finally, the generated acetic acid and acetic anhydride were removed by vacuum distillation to obtain BJTO.

[0020] IR and NMR spectra are shown in Figure 1 and Figure 2 , Figure 1 Compared with tung oil anhydride and tung oil anhydride, BJT and BJTO in the reaction showed obvious secondary amine stretching vibration, which can indicate that phenylhydrazine was successfully added to tung oil anhydride and tung oil anhydride respectively. -1 Peaks appeared near the carbon-carbon double bond, which is due to the carbon-hydrogen stretching vibration on the carbon-carbon double bond. Tungsten anhydride, tungoleic anhydride, BJT and BJTO all retained the double bond, which can explain that the double bond was not destroyed when phenylhydrazine was added to the anhydride. More noteworthy is that Figure 1 In the middle shaded area 1, the peaks of BJT and BJTO are greatly weakened compared with those of tung oil anhydride and tung oil anhydride, respectively. This is a signal that the anhydride is fully reacted. The primary amine on the phenylhydrazine is converted into anhydride and then condensed to form a maleimide structure, which also explains the Figure 1 The peak phenomenon of BJT and BJTO appears in the middle shaded area 2. Figure 2 Nuclear magnetic spectrum, using Chemdraw's nuclear magnetic hydrogen spectrum prediction, the peak positions of the hydrogen spectra of BJT and BJTO are basically the same, which can assist in proving the successful synthesis of BJT and BJTO.

[0021] Example 2

[0022] Preparation of BJT: 37 g of tauricin was dissolved in 200 mL of acetic acid. After complete dissolution, 9.5 g of phenylhydrazine was added and the mixture was allowed to react at 40°C under closed conditions for 28 hours. The acetic acid in the reaction system was removed by vacuum distillation to produce an adduct of phenylhydrazine and tauricin. The adduct of phenylhydrazine and tauricin was then dissolved in 200 mL of acetic anhydride at room temperature for a dehydration and cyclization reaction for 16 hours, maintaining the system in a closed state. Finally, the acetic anhydride was removed by vacuum distillation to produce BJT.

[0023] Preparation of BJTO: 28 g of tung oil anhydride was dissolved in 200 mL of acetic acid. After complete dissolution, 9.5 g of phenylhydrazine was added and the mixture was reacted at 35°C under closed conditions for 26 hours. The acetic acid in the reaction system was distilled off by vacuum to produce an adduct of phenylhydrazine and tung oil anhydride. The adduct of phenylhydrazine and tung oil anhydride was then dissolved in 200 mL of acetic anhydride at room temperature for a dehydration and cyclization reaction for 16 hours, keeping the system closed. Finally, the acetic anhydride was distilled off by vacuum to produce BJTO.

[0024] Example 3

[0025] Preparation of BJT: 38 g of tauricin (tauricin) was dissolved in 200 mL of acetic acid. After complete dissolution, 10 g of phenylhydrazine was added and the mixture was allowed to react at 45°C for 30 h under closed conditions. The acetic acid in the reaction system was removed by vacuum distillation to produce an adduct of phenylhydrazine and tauricin. The adduct of phenylhydrazine and tauricin was then dissolved in 200 mL of acetic anhydride at room temperature for a dehydration and cyclization reaction for 14 h, maintaining the system in a closed state. Finally, the acetic anhydride was removed by vacuum distillation to produce BJT.

[0026] Preparation of BJTO: 29 g of tung oil anhydride was dissolved in 200 mL of acetic acid. After complete dissolution, 10 g of phenylhydrazine was added and the mixture was allowed to react at 35°C for 30 h under closed conditions. The acetic acid in the reaction system was removed by vacuum distillation to produce an adduct of phenylhydrazine and tung oil anhydride. This adduct of phenylhydrazine and tung oil anhydride was then dissolved in 200 mL of acetic anhydride at room temperature for a dehydration and cyclization reaction for 14 h, maintaining the reaction system in a closed state. Finally, the acetic anhydride was removed by vacuum distillation to produce BJTO.

[0027] Example 4

[0028] Preparation of BJT: 39 g of tungiatic anhydride was dissolved in 200 mL of acetic acid. After complete dissolution, 10.8 g of phenylhydrazine was added and reacted at 35°C under closed conditions for 24 h. The acetic acid in the reaction system was distilled off by vacuum distillation to prepare an adduct of phenylhydrazine and tungiatic anhydride. Then, the adduct of phenylhydrazine and tungiatic anhydride was dissolved in 200 mL of acetic anhydride at room temperature and dehydrated and condensed for 12 h. Finally, the acetic anhydride was distilled off by vacuum distillation to prepare BJT.

[0029] Preparation of BJTO: 28.9 g of tung oil anhydride was dissolved in 200 mL of acetic acid. After complete dissolution, 10.8 g of phenylhydrazine was added and the mixture was reacted at 35°C under closed conditions for 24 h. The acetic acid in the reaction system was distilled off by vacuum to prepare an adduct of phenylhydrazine and tung oil anhydride. Then, the adduct of phenylhydrazine and tung oil anhydride was dissolved in 200 mL of acetic anhydride at room temperature and dehydrated and condensed for 12 h. Finally, the acetic anhydride was distilled off by vacuum to prepare BJTO.

[0030] Comparative Example 1:

[0031] The synergistic effect between tung oil-derived auxiliary heat stabilizers (BJT and BJTO) and the calcium stearate / zinc composite heat stabilizer was investigated using a commercially available general-purpose calcium stearate / zinc composite heat stabilizer as the basis. The performance of the BJT and BJTO prepared in Example 1 was compared. The formulations for each PVC film are detailed in Table 1.

[0032] Table 1 PVC film formula

[0033]

[0034] Sample preparation:

[0035] The materials of the control group (PVC-1) and the experimental group (PVC-2 to PVC-5) were mixed evenly, and then plasticized on a two-roll plasticator at 170±2°C for 3 minutes to prepare test pieces with a thickness of 0.3 mm.

[0036] Tensile properties test:

[0037] Tensile Properties Test: Dumbbell-shaped tensile specimens were punched using a punching machine. The tensile zone thickness was ~0.3 mm, the width was 4 mm, and the original gauge length was 20 mm. The tensile properties of the material were measured using a CMT400 microcomputer-controlled electronic universal testing machine (Shenzhen Xinsansi) according to GB / T 13022-91, "Test Method for Tensile Properties of Plastic Films," at a test speed of 20 mm / min.

[0038] Glass transition temperature (Tg): A TA Instruments Q800 dynamic mechanical analyzer (DMA) was operated in tension mode with a pulling force of 0.01 N, an oscillation amplitude of 15 mm, and a frequency of 1 Hz. The sample was 15 mm long, 5 mm wide, and 1 mm thick.

[0039] The mechanical properties of PVC-1, PVC-2 and PVC-3 are compared, and the results are shown in Table 1. It can be found that the addition of BJT and BJTO can reduce the glass transition temperature of the material while ensuring that the mechanical properties of PVC remain unchanged.

[0040] Table 1 Comparison of mechanical properties of PVC materials in the experimental group and the control group

[0041]

[0042] Heat aging test: According to ISO 305:1990(E). Each PVC film was placed in an XH-314B heat aging oven (Xihua, China). Samples were taken out at regular intervals (one sample at a time) and their color changes at adjacent time points were observed. Figure 3 Comparison shows that the long-term thermal stability of PVC-2 and PVC-3 is significantly better than that of PVC-2 and PVC-3, indicating that BJT and BJTO can effectively delay the "zinc burn" phenomenon of calcium stearate / zinc heat stabilizers and have a good synergistic stabilization effect with traditional calcium stearate / zinc heat stabilizers, providing a feasible solution to the "zinc burn" phenomenon caused by existing traditional calcium / zinc heat stabilizers.

Claims

1. A method for preparing a tung oil-derived PVC auxiliary heat stabilizer, characterized in that: The preparation steps are as follows: dissolving 35-40 g of anhydride in 200 mL of acetic acid according to proportion, wherein the anhydride is tung oil anhydride or tung maleic anhydride; adding 9-11 g of phenylhydrazine after the anhydride is completely dissolved; reacting at 35-45° C. under closed conditions for 24-30 hours; distilling off the acetic acid in the reaction system by reduced pressure distillation to prepare an adduct of phenylhydrazine and the anhydride; then dissolving the adduct of phenylhydrazine and the anhydride in 200 mL of acetic anhydride; keeping the system in a closed state for reaction for 12-16 hours at room temperature; and then distilling off the acetic anhydride by reduced pressure distillation to obtain a tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure.

2. The method for preparing the tung oil-derived PVC auxiliary heat stabilizer according to claim 1, wherein: According to the invention, 35-40 g of anhydride is dissolved in 200 mL of acetic acid, wherein the anhydride is tung oil anhydride or tung maleic anhydride. After the anhydride is completely dissolved, 9-11 g of phenylhydrazine is added, and the mixture is reacted at 35° C. under closed conditions for 24 hours. The acetic acid in the reaction system is distilled off by reduced pressure to prepare an adduct of phenylhydrazine and anhydride. The adduct of phenylhydrazine and anhydride is then dissolved in 200 mL of acetic anhydride, and the mixture is reacted for 12 hours while the system is kept closed at room temperature. The acetic anhydride is then distilled off by reduced pressure to obtain a tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure.

3. A tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure obtained by the preparation method according to claim 1 or 2.

4. The tung oil-derived PVC auxiliary heat stabilizer containing an N-maleimide structure according to claim 3, characterized in that: The structure is as follows:

5. Use of the BJT or BJTO according to claim 4 in the preparation of a thermal stabilizer.

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