PVC organic composite heat stabilizer and preparation method thereof

Abstract

The application belongs to the field of plastic chemical additives and processing technology, and relates to a PVC organic composite heat stabilizer and a preparation method thereof.The PVC organic composite heat stabilizer disclosed by the application can be applied to the processing and production of PVC, specifically the processing and production of hard and soft PVC products, can replace organic tin heat stabilizers, can solve the problems of large odor and easy precipitation during processing, and has superior plasticizing effect of organic tin.

Description

Technical Field

[0001] This invention belongs to the field of plastic chemical additives and their processing technology, and relates to a PVC organic composite heat stabilizer and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) is one of the world's five major general-purpose plastics, widely used in toys, packaging, medical supplies, and other fields. PVC plastic has poor thermal stability and is easily decomposed by heat during processing. Therefore, PVC heat stabilizers must be added during processing to provide protection. PVC heat stabilizers are generally classified into lead salts, organotin compounds, metal soaps, and rare earth compounds. However, commonly available lead salts and organotin heat stabilizers have a certain degree of toxicity and are trending towards being replaced by other environmentally friendly rare earth and calcium-zinc heat stabilizers.

[0003] Ordinary calcium and zinc stabilizers mostly consist of fatty acid calcium and zinc salts and some auxiliary stabilizers such as β-diketone, polyols, and hydrotalcite. Their transparency and heat resistance are significantly inferior to those of organotin stabilizers. To improve their performance and replace organotin stabilizers, new effective ingredients must be introduced. Moreover, the presence of only calcium stearate and zinc stearate is insufficient to meet the processing requirements of PVC.

[0004] Therefore, how to provide a high-performance PVC heat stabilizer to replace organotin heat stabilizers is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention addresses the shortcomings of the prior art by providing a PVC organic composite heat stabilizer and its preparation method.

[0006] It should be noted that currently only calcium stearate and zinc stearate are available, which are insufficient to meet the processing requirements of PVC. Therefore, many auxiliary stabilizers need to be added to improve its heat resistance. These auxiliary stabilizers mainly include polyols, epoxy compounds, β-diketones, hydrotalcite, and zeolites. The PVC organic composite heat stabilizer disclosed in this invention can be applied to PVC processing and production, specifically the processing and production of rigid and flexible PVC products. It can replace organotin heat stabilizers, not only solving the problems of strong odor and easy precipitation during processing, but also possessing the superior plasticizing effect of organotin.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A PVC organic composite heat stabilizer, wherein the PVC organic composite heat stabilizer comprises, by weight parts:

[0009]

[0010] Stabilizer A is tetrahydroxyalkyl glycourea, with the following chemical structural formula:

[0011]

[0012] The stabilizer B is zinc stearate, lanthanum stearate, zinc benzoate, zinc octanoate, or zinc laurate;

[0013] The stabilizer C is a dihydropyridine ester, with the following chemical structural formula:

[0014]

[0015] The stabilizer D is calcium stearate, calcium benzoate, calcium octanoate, or calcium laurate.

[0016] The stabilizer E is adipic acid (plasticizer) or ACR resin (impact modifier), and its main function is to accelerate PVC plasticization and improve molding ability.

[0017] Optionally, the pentaerythritol ester is pentaerythritol monostearate, the sac is tris(2-hydroxyethyl) isocyanurate, and the antioxidant is antioxidant 1010, 1076, or a phosphite antioxidant, all of which are commercially available products.

[0018] Furthermore, the tetrahydroxyalkylglycourea is synthesized from dodecylaldehyde and glycourea at 120℃-190℃ in the presence of p-toluenesulfonic acid as a catalyst;

[0019]

[0020] Furthermore, the preparation of the dihydropyridine ester is carried out using a two-step method:

[0021]

[0022] The preparation method specifically includes the following steps:

[0023] (1) Ethyl acetoacetate and stearyl alcohol were subjected to transesterification at 120℃-190℃ to obtain octadecyl acetoacetate;

[0024] (2) Acetic acid was added to the octadecyl acetoacetate obtained in step (1) until it was weakly acidic. Then ammonium acetate and phase transfer catalyst tetradecyltrimethylammonium chloride were added and heated. Hemotropin aqueous solution was slowly added under stirring. After the reaction was completed, the temperature was lowered, and the product was obtained by filtration, washing and drying.

[0025] Furthermore, in step (1), the molar ratio of ethyl acetoacetate to stearyl alcohol is (1.2-1.8):1, and the reaction time is 2-5 h.

[0026] In step (2), the molar ratio of octadecyl acetoacetate to hexamethylenetetramine is (4-6):1, the molar ratio of octadecyl acetoacetate to ammonium acetate is (1-1.5):1, and the weight ratio of octadecyl acetoacetate to tetradecyltrimethylammonium chloride is 1000:(1-5).

[0027] Furthermore, the reaction temperature in step (2) is 125℃-135℃, and the reaction time is 2-8h.

[0028] It should be noted that the dihydropyridine ester is a derivative of dihydropyridine. Because dihydropyridine has a nitrogen-containing heterocyclic structure, it can replace unstable chlorine in the PVC molecular chain, prevent PVC degradation, and improve the initial color.

[0029] Furthermore, due to the small molecular weight of dihydropyridine, there is a risk of precipitation in PVC materials. Therefore, the dihydropyridine ester used in this invention is a modified and chain-extended form of dihydropyridine. The introduced stearic acid molecular chain has good compatibility with PVC, which solves the problem of easy precipitation of dihydropyridine while retaining its thermal stability, making it a good heat-stabilizing agent.

[0030] The tetrahydroxyalkyl glycourea has a C=O structure and multiple hydroxyl groups on its polymer chain, which gives it coordination ability and allows it to absorb HCl. When combined with zinc stearate, it can effectively complex zinc chloride, inhibit the "zinc burning" phenomenon in PVC, improve the heat resistance of PVC, and solve the defect of poor long-term thermal stability of calcium-zinc stabilizers.

[0031] This invention also claims protection for a method for preparing a PVC organic composite heat stabilizer, specifically comprising the following steps:

[0032] In a high-speed mixer at 200–600 r / min and a temperature of 80–90°C, add stabilizer A, stabilizer B, stabilizer C, stabilizer D, stabilizer E, pentaerythritol ester, cyproconazole and antioxidant as described above, mix for 10–30 min, and obtain the PVC organic composite heat stabilizer once the mixture is homogeneous.

[0033] It should be noted that during the product mixing process, heating to 80-90℃ helps to remove moisture from the materials; and the order of adding materials has no significant impact on product quality.

[0034] As can be seen from the above technical solutions, compared with the prior art, the PVC organic composite heat stabilizer and its preparation method provided by the present invention have the following superior effects:

[0035] 1. The tetrahydroxyalkyl glycourea in this invention acts as the main stabilizer, which improves the long-term thermal stability of PVC. When combined with dihydropyridine ester, zinc stearate, and cyproconazole, it produces a good synergistic effect, effectively complexing zinc chloride and alleviating the "zinc burning" phenomenon of PVC. It can also absorb a large amount of HCl, which greatly improves the long-term thermal stability and weather resistance of PVC.

[0036] 2. The PVC organic composite heat stabilizer disclosed in this invention contains highly polar substances, which can rapidly plasticize PVC, and the plasticizing effect is close to that of organotin; moreover, its long-term thermal stability is close to that of organotin, and it can replace organotin stabilizer products.

[0037] 3. The PVC organic composite heat stabilizer disclosed in this invention has good compatibility with PVC resin because it is mainly composed of large-molecule organic substances, which can effectively prevent the problem of precipitation.

[0038] 4. The PVC organic composite heat stabilizer disclosed in this invention is free of heavy metals, non-toxic, environmentally friendly, and odorless. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0040] Figure 1 The figures show the heat resistance test results of the heat stabilizers prepared in the examples and comparative examples after being used in PVC products. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] This invention discloses a method for preparing a PVC organic composite heat stabilizer.

[0043] To better understand the present invention, the following embodiments are provided for further detailed description of the present invention, but they should not be construed as limiting the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are also considered to fall within the protection scope of the present invention.

[0044] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0045] The formulations for Examples 1-6 are shown in Table 1, and the preparation method of the PVC organic composite heat stabilizer is as follows:

[0046] In a high-speed mixer at 200–600 r / min and a temperature of 80–90°C, add tetrahydroxyalkyl glycourea, zinc stearate, dihydropyridine ester, calcium stearate, ACR resin, pentaerythritol ester, saccharin and antioxidant 1010, mix, and obtain the PVC organic composite heat stabilizer after uniform mixing.

[0047] Table 1

[0048]

[0049] Effect test:

[0050] Table 2 shows the formulas for the stabilizers used in static oven heat resistance tests.

[0051] Table 2

[0052]

[0053] Among them, the heat stabilizers used in Examples 1 to 6, and the comparative samples 1 to 3, totaling nine experimental samples.

[0054] First, mix the raw materials according to the formula ratio, and then plasticize them for 5 minutes on a 170℃ two-roll mill. Then, stretch them into 0.4mm sample sheets. Next, cut them into 30*40mm samples, place them on a glass plate, and put them into a 180℃ oven. Take out the PVC sheets every 30 minutes and observe the blackening of the PVC sheets. The whiter the color, the better the heat resistance of the heat stabilizer.

[0055] The experimental results are shown in Table 3 and Figure 1 As shown.

[0056] Table 3

[0057]

[0058] The experimental results are shown in Table 3 and Figure 1 This indicates that the heat resistance of Examples 1-4 is close to that of the organotin sample in Comparative Example 3.

[0059] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A PVC organic composite heat stabilizer, characterized in that, The PVC organic compound heat stabilizer comprises, in weight parts: The stabilizer A is tetrahydroxyalkyl glycol, and its chemical structural formula is as follows: The stabilizer B is zinc stearate, lanthanum stearate, zinc benzoate, zinc octanoate or zinc laurate; The stabilizer C is dihydropyridine ester, and its chemical structural formula is as follows: The stabilizer D is calcium stearate, calcium benzoate, calcium octanoate or calcium laurate; The stabilizer E is adipic acid or ACR resin; The preparation method of the PVC organic compound heat stabilizer specifically comprises the following steps: In a high-speed mixer at 200-600 r / min, with a temperature of 80-90 ℃, the stabilizer A, the stabilizer B, the stabilizer C, the stabilizer D, the stabilizer E, pentaerythritol ester, sik and an antioxidant are added and mixed for 10-30 min, and the PVC organic compound heat stabilizer is obtained after uniform mixing.

2. The PVC organic composite heat stabilizer according to claim 1, characterized in that, The pentaerythritol ester is pentaerythritol monostearate, the sik is tris(2-hydroxyethyl) isocyanurate, and the antioxidant is antioxidant 1010, 1076 or a phosphite antioxidant.

3. The PVC organic composite heat stabilizer according to claim 1 or 2, characterized in that, The tetrahydroxyalkyl glycol is synthesized from dodecanal and glycol under the action of a catalyst p-toluenesulfonic acid at 120-190 ℃.

4. The PVC organic composite heat stabilizer according to claim 1 or 2, characterized in that, The preparation method of the dihydropyridine ester specifically comprises the following steps: (1) acetyl acetate ethyl ester and stearyl alcohol are subjected to ester exchange reaction at 120-190 ℃ to obtain acetyl acetate octadecyl ester; (2) acetic acid is added to the acetyl acetate octadecyl ester obtained in step (1) to weakly acidic, then ammonium acetate and a phase transfer catalyst tetradecyl trimethyl ammonium chloride are added, heating and slowly adding an aqueous solution of urotropine under stirring, and after the reaction is completed, the temperature is lowered, and the dihydropyridine ester is obtained after filtration, washing and drying.

5. The PVC organic composite heat stabilizer according to claim 4, characterized in that, In step (1), the molar ratio of acetyl acetate ethyl ester to stearyl alcohol is (1.2-1.8):1, and the reaction time is 2-5 h.

6. The PVC organic composite heat stabilizer according to claim 4, characterized in that, In step (2), the molar ratio of acetyl acetate octadecyl ester to urotropine is (4-6):1, the molar ratio of acetyl acetate octadecyl ester to ammonium acetate is (1-1.5):1, and the weight ratio of acetyl acetate octadecyl ester to tetradecyl trimethyl ammonium chloride is 1000:(1-5).

7. The PVC organic composite heat stabilizer according to claim 6, characterized in that, The reaction temperature is 125-135 ℃, and the reaction time is 2-8 h.

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