A rare earth composite stabilizer for PVC and its preparation method

Abstract

The present invention provides a rare earth composite stabilizer for PVC and its preparation method. The rare earth composite stabilizer comprises the following components in parts by weight: 2-10 parts of a triazine carboxylic acid rare earth salt, 1-5 parts of a stearate, and 1-5 parts of a functional additive. The preparation method comprises the following steps: placing the triazine carboxylic acid rare earth salt, stearate, and functional additive in a ball mill, adding anhydrous ethanol, mixing at 200-500 rpm for 10-20 minutes, and post-processing to obtain the rare earth composite stabilizer. The rare earth composite stabilizer of the present invention effectively improves the mechanical properties, thermal stability, and light aging resistance of PVC materials. The rare earth composite stabilizer has abundant raw material sources and a simple preparation process, making it suitable for industrial large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of PVC stabilizers, and in particular relates to a rare earth composite stabilizer for PVC and a preparation method thereof. Background Art

[0002] Polyvinyl chloride (PVC) is one of the most widely used synthetic resins in the world. It boasts advantages such as lightweight, excellent chemical resistance, superior mechanical properties, and a simple production process. However, a drawback of PVC is that its decomposition temperature is typically lower than its processing temperature. At temperatures above 100°C or after prolonged exposure to sunlight, it decomposes to produce hydrogen chloride, which then undergoes autocatalytic decomposition, causing discoloration and a rapid decline in physical and mechanical properties. Therefore, to prevent decomposition of PVC resin during processing and molding, stabilizers must be added.

[0003] Currently, widely used PVC stabilizers can be mainly divided into lead salt stabilizers, metal soap stabilizers, organotin stabilizers, calcium zinc stabilizers, and rare earth stabilizers. Among them, rare earth stabilizers are a new type of stabilizer developed in recent years. They have advantages such as low toxicity, good transparency, and high weather resistance. However, when used alone, they still have problems such as poor initial thermal stability of the material. In the existing technology, rare earth salts are modified with carboxylic acid compounds such as imidazole-4,5-dicarboxylic acid. Although the thermal stability of the resulting stabilizer is improved, the light stability is relatively poor, and the thermal stability still needs further improvement.

[0004] In order to improve the stability of rare earth stabilizers, the existing technology improves the thermal stability of rare earth stabilizers by adding functional additives such as polyurea. However, although the thermal stability is improved when applied to PVC materials, there are still disadvantages such as low mechanical properties and poor initial thermal stability of the material. In addition, the light stability is still relatively poor, resulting in the material being improved ineffectively.

[0005] In view of the problems existing in the prior art, how to provide a rare earth composite stabilizer so that the prepared PVC material has better mechanical properties, thermal stability and light aging resistance is a problem to be solved urgently by the present invention. Summary of the Invention

[0006] The object of the present invention is to provide a rare earth composite stabilizer for PVC and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides a rare earth composite stabilizer for PVC, characterized in that the rare earth composite stabilizer comprises the following components in parts by weight: 2-10 parts of a triazine carboxylic acid rare earth salt, 1-5 parts of a stearate, and 1-5 parts of a functional additive;

[0008] The triazine carboxylic acid rare earth salt is 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt;

[0009] The functional auxiliary agent is modified polyurea.

[0010] As a further improvement, the synthesis of the 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt comprises the following steps:

[0011] (1) Dissolve the rare earth salt in deionized water by stirring, then add 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and anhydrous ethanol, and heat under reflux at 60-70° C. while stirring;

[0012] (2) adding NaOH solution to the step (1) to adjust the pH value to 6-7, continuing stirring for 2-3 hours, and post-treating to obtain 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt.

[0013] As a further improvement, the rare earth salt is at least one of rare earth chloride, rare earth nitrate or rare earth sulfate.

[0014] As a further improvement, the rare earth is at least one of the light rare earth elements selected from lanthanum, cerium, praseodymium, neodymium, promethium, samarium and europium.

[0015] As a further improvement, the modified polyurea is prepared by reacting isocyanate, polyetheramine and silane coupling agent.

[0016] As a further improvement, the synthesis of the modified polyurea comprises the following steps:

[0017] (1) slowly adding isocyanate dissolved in an organic solvent to the polyetheramine while stirring, and reacting for 1-3 hours under a nitrogen atmosphere;

[0018] (2) Adding a silane coupling agent to step (1), continuing to stir and react for 1-3 hours, completing the reaction, and post-processing to obtain a modified polyurea.

[0019] As a further improvement, the isocyanate is at least one of hexamethylene diisocyanate, toluene-2,4-diisocyanate, isophorone diisocyanate, and 4,4'-diphenylmethane diisocyanate.

[0020] In order to have better mechanical properties, preferably, the isocyanate is 4,4'-diphenylmethane diisocyanate.

[0021] As a further improvement, the silane coupling agent is at least one of KH-550, KH-570, KH-540, and A-151.

[0022] In order to have better stability, preferably, the silane coupling agent is KH-550 and the organic solvent is N,N-dimethylformamide.

[0023] As a further improvement, the stearate is at least one of calcium stearate, zinc stearate, barium stearate, aluminum stearate, magnesium stearate, and sodium stearate.

[0024] In order to have better stability, preferably, the stearate is calcium stearate.

[0025] The present invention provides a method for preparing a rare earth composite stabilizer for PVC, which is characterized by comprising the following steps:

[0026] The triazine carboxylic acid rare earth salt, stearate and functional additive are placed in a ball mill, anhydrous ethanol is added, and the mixture is mixed at 200-500 rpm for 10-20 minutes, and then post-treated to obtain a rare earth composite stabilizer.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a rare earth composite stabilizer for PVC and a preparation method thereof. When the prepared rare earth composite stabilizer is used in PVC material, it not only improves the mechanical properties of the PVC material, but also significantly improves the thermal stability and light aging resistance of the PVC material. In addition, the raw material source of the rare earth composite stabilizer is abundant, the preparation process is simple, and the stabilizer is suitable for industrial large-scale production. DETAILED DESCRIPTION

[0029] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following examples are illustrative of the present invention and are intended only to illustrate the present invention and are not intended to limit the present invention. Other combinations and various modifications within the scope of the present invention may be made without departing from the spirit or scope of the present invention.

[0030] In the following examples, except for triazine carboxylic acid rare earth salt, imidazole carboxylic acid rare earth salt, polyurea, and modified polyurea, the remaining compound monomers and related reagents used can be purchased from the market, among which 2,4,6-tris(aminocaproic acid)-1,3,5-triazine was purchased from Jiangsu Aikon Biopharmaceutical Research and Development Co., Ltd., model AK00IDFP, polyetheramine was purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd., model P108071, and PVC was purchased from Guangdong Weilinna New Materials Technology Co., Ltd., model PVC1302.

[0031] The preparation method of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt comprises the following steps:

[0032] (1) 10 mmol of lanthanum nitrate hexahydrate was dissolved in 20 mL of deionized water by stirring, and then 10 mmol of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and 20 mL of anhydrous ethanol were added thereto, and the mixture was heated under reflux at 60° C. and stirred for half an hour;

[0033] (2) After adding 1 mol / L NaOH solution to step (1) to adjust the pH value to 6, stirring was continued for 2 h. After the reaction was completed, suction filtration was performed and the mixture was repeatedly washed with anhydrous ethanol and water for 3 times. The obtained solid was dried at 80° C. to obtain 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt.

[0034] The preparation method of imidazole-4,5-dicarboxylic acid rare earth salt comprises the following steps:

[0035] (1) 8 mmol of imidazole-4,5-dicarboxylic acid was dissolved in 20 mL of deionized water by stirring, and then 5 mmol of lanthanum chloride solution was added thereto, and the mixture was heated under reflux at 60° C. and stirred for half an hour;

[0036] (2) After adding 1 mol / L NaOH solution to step (1) to adjust the pH value to 5, stirring was continued for 5 h. After the reaction was completed, suction filtration was performed and the mixture was washed three times with deionized water. The obtained solid was dried at 80° C. to obtain imidazole-4,5-dicarboxylic acid rare earth salt.

[0037] The preparation method of polyurea comprises the following steps:

[0038] 11 mmol of 4,4'-diphenylmethane diisocyanate was dissolved in 30 mL of N,N-dimethylformamide, and then slowly added dropwise to 10 mmol of polyetheramine while stirring. The mixture was reacted for 3 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was dried at 110°C for 50 minutes to obtain polyurea.

[0039] The preparation method of modified polyurea comprises the following steps:

[0040] (1) Dissolve 11 mmol of 4,4'-diphenylmethane diisocyanate in 30 mL of N,N-dimethylformamide, then slowly add dropwise to 10 mmol of polyetheramine while stirring, and stir under nitrogen atmosphere for 2 h;

[0041] (2) Add 1 mmol of silane coupling agent KH-550 to step (1), stir and react for 3 hours, and after the reaction is completed, bake at 110° C. for 30 minutes to obtain modified polyurea.

[0042] The preparation methods of Examples 1-3 and Comparative Example 2 comprise the following steps:

[0043] Triazine carboxylic acid rare earth salt, stearate, and functional additives were placed in a ball mill according to weight, 30 mL of anhydrous ethanol was added and mixed, the mixture was mixed at 300 rpm for 20 min, filtered, and dried with cold air to obtain a rare earth composite stabilizer.

[0044] The preparation method of Comparative Example 1 comprises the following steps:

[0045] According to weight, imidazole carboxylic acid rare earth salt, stearate, and functional additives were placed in a ball mill, 30 mL of anhydrous ethanol was added and mixed, the mixture was mixed at 300 rpm for 20 min, filtered, and dried with cold air to obtain a rare earth composite stabilizer.

[0046] The components and contents used in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1 below:

[0047] Table 1

[0048]

[0049] Take 100 parts of PVC and 5 parts of composite stabilizer by weight, stir mechanically at 40°C for 30 minutes at a stirring speed of 800 rpm to obtain PVC formula material, and perform performance testing accordingly.

[0050] The test method is as follows:

[0051] Tensile strength: tested according to GB / T 1040-2006;

[0052] Impact strength: tested according to GB / T 1043-1993;

[0053] Bending strength: tested according to GB / T 9341-2008;

[0054] Congo red discoloration: tested according to GB / T 2917.1-2002;

[0055] Light aging resistance: tested according to GB / T 16422.3-2014. The wavelength of the UV lamp is 313nm. The sample is exposed to light at 70℃ for a total test time of 300h. The tensile strength test is performed every 150h.

[0056] The test results are shown in Table 2 and Table 3, as follows:

[0057] Table 2

[0058]

[0059] Table 3

[0060]

[0061] It can be seen from Example 2 and Comparative Example 1 in Tables 2 and 3 that, compared with the rare earth composite stabilizer prepared from imidazole-4,5-dicarboxylic acid rare earth salt, the rare earth composite stabilizer prepared using 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt, when applied to PVC material, has a smaller change in tensile strength with the increase of light aging time, indicating better anti-light aging performance, a longer Congo red to blue time, good thermal stability, and can also improve the impact strength and flexural strength of the PVC material to a certain extent.

[0062] It can be seen from Example 2 and Comparative Example 2 that compared with the rare earth composite stabilizer prepared using conventional functional additives such as unmodified polyurea, the rare earth composite stabilizer prepared using polyurea modified by a silane coupling agent has better tensile strength, impact strength, and flexural strength when applied to PVC materials, and can also prolong the time for Congo red to turn blue to a certain extent, indicating that the thermal stability is better. At the same time, as the light aging time increases, the change in tensile strength is smaller, and the anti-light aging performance is better.

[0063] From the test results of Examples 1-3, it can be seen that the rare earth composite stabilizer prepared by the preparation method provided by the present invention, when applied to PVC materials, has better tensile strength, impact strength, and flexural strength, indicating better mechanical properties, and has a longer Congo red to blue time, indicating better heat resistance. Even under longer illumination time, the PVC material still has good tensile strength, indicating better anti-light aging performance.

[0064] The above embodiments are only for illustrating the technical concept and features of the present invention. Its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rare earth composite stabilizer for PVC, characterized in that: The rare earth composite stabilizer comprises the following components in parts by weight: 2-10 parts of triazine carboxylic acid rare earth salt, 1-5 parts of stearate, and 1-5 parts of functional additive; The triazine carboxylic acid rare earth salt is 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt; The functional additive is modified polyurea; The preparation method of the 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt comprises the following steps: (1) Dissolve the rare earth salt in deionized water by stirring, then add 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and anhydrous ethanol, and heat under reflux at 60-70°C while stirring; (2) adding NaOH solution to the mixture in step (1) to adjust the pH value to 6-7, continuing stirring for 2-3 hours, and post-treating to obtain 2,4,6-tris(aminocaproic acid)-1,3,5-triazine rare earth salt; The rare earth is at least one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and europium; The synthesis of the modified polyurea comprises the following steps: (1) Slowly add isocyanate dissolved in an organic solvent to the polyetheramine while stirring, and react under a nitrogen atmosphere for 1-3 hours; (2) adding a silane coupling agent to step (1), continuing to stir and react for 1-3 hours, completing the reaction, and post-processing to obtain a modified polyurea; The isocyanate is at least one of hexamethylene diisocyanate, toluene-2,4-diisocyanate, isophorone diisocyanate, and 4,4'-diphenylmethane diisocyanate.

2. A rare earth composite stabilizer for PVC according to claim 1, characterized in that: The rare earth salt is at least one of rare earth chloride, rare earth nitrate or rare earth sulfate.

3. A rare earth composite stabilizer for PVC according to claim 1, characterized in that: The silane coupling agent is at least one of KH-550, KH-570, KH-540, and A-151.

4. A rare earth composite stabilizer for PVC according to claim 1, characterized in that: The stearate is at least one of calcium stearate, zinc stearate, barium stearate, aluminum stearate, magnesium stearate, and sodium stearate.

5. The method for preparing a rare earth composite stabilizer for PVC according to claim 1, characterized in that: The following steps are involved: The triazine carboxylic acid rare earth salt, stearate and functional additive are placed in a ball mill, anhydrous ethanol is added, and the mixture is mixed at 200-500 rpm for 10-20 minutes, and then post-treated to obtain a rare earth composite stabilizer.

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