Polyhydroxymethyl melamine-based PVC (polyvinyl chloride) composite heat stabilizer
By using polymethylol melamine-based composite heat stabilizers and utilizing the effects of their amino and primary hydroxyl groups, the problems of toxicity and insufficient performance of PVC heat stabilizers are solved, achieving a non-toxic, environmentally friendly and low-cost high-efficiency heat stabilization effect.
Patent Information
- Application Number
- CN202511036029.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-26
- Publication Date
- 2025-09-30
AI Technical Summary
The lead salt compounds in existing PVC heat stabilizers are toxic, which limits their use. In addition, the performance of existing environmentally friendly heat stabilizers is insufficient and it is difficult to meet the demand for low cost and high performance.
A composite heat stabilizer with polymethylol melamine as the main component, combined with zinc stearate, hydrotalcite and auxiliary heat stabilizers, absorbs HCl and chelates Zn2+ through the action of the amino group and primary hydroxyl group of polymethylol melamine, thereby improving the thermal stability of PVC.
It achieves non-toxic and environmentally friendly high-efficiency PVC thermal stability, significantly improves the thermal stability of PVC, and reduces production costs.
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Figure CN120718341A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a PVC heat stabilizer, in particular to a polymethylol melamine-based PVC composite heat stabilizer, and belongs to the field of polymer material processing aids. Background Art
[0002] PVC is prone to decomposition at processing temperatures, causing the product's color to darken and its structure and properties to change. Therefore, heat stabilizers must be added during PVC processing to prevent or reduce its decomposition. Currently, commonly used heat stabilizers include lead salts, organotin compounds, metal soaps, and composite heat stabilizers. Lead salt heat stabilizers are the earliest developed PVC heat stabilizers and exhibit excellent thermal stability. However, due to the high toxicity of lead salt compounds, which pose a threat to human health and environmental safety, countries around the world are gradually restricting their use. Therefore, it is of great significance to develop low-cost, high-performance, environmentally friendly PVC composite heat stabilizers to replace lead salt heat stabilizers and promote the "lead-free" PVC industry.
[0003] Nitrogen-containing compounds are an important class of environmentally friendly PVC heat stabilizers, including nitrogen-containing heterocyclic compounds, amides, Schiff bases, and amino-based heat stabilizers. These compounds enhance the heat resistance of PVC by absorbing hydrogen chloride released during PVC thermal degradation, reacting with conjugated polyene groups in the PVC chain, and coordinating with metal ions. To further enhance the performance of PVC composite heat stabilizers, the development of new, highly efficient, and low-cost nitrogen-containing organic heat stabilizers remains a key technical challenge for those skilled in the art. Summary of the Invention
[0004] The present invention aims to provide a polymethylol melamine-based PVC composite heat stabilizer, which has polymethylol melamine as a main component, has the advantages of being non-toxic, environmentally friendly and low in cost, and can significantly improve the thermal stability of PVC.
[0005] In order to achieve the above objectives, the technical solution adopted by the present invention is to provide a polymethylol melamine-based PVC composite heat stabilizer, comprising the following components by mass: Polymethylol melamine: 40-60%; Zinc stearate: 25-35%; Hydrotalcite: 10-25%; Auxiliary heat stabilizer: 3-6%; The molecular structural formula of the polymethylol melamine is: , where x is 1 or 2, y is 1 or 2, and z is 1 or 2; The auxiliary heat stabilizer is β -diketone compound or 1,3-dimethyl-6-aminouracil.
[0006] Furthermore, the polymethylol melamine is prepared using melamine and paraformaldehyde as raw materials.
[0007] Furthermore, the β - The diketone compound is dibenzoylmethane, stearoylbenzoylmethane, zinc acetylacetonate or calcium acetylacetonate.
[0008] The present invention uses polymethylol melamine as the main component of the PVC composite heat stabilizer. The molecular structure of polymethylol melamine contains a large number of amino groups and primary hydroxyl groups. The amino groups can absorb HCl released by PVC degradation and inhibit the autocatalytic degradation of PVC by HCl. The primary hydroxyl groups can chelate Zn 2+ , inhibiting zinc burn. Through these effects, polymethylol melamine exhibits excellent thermal stability for PVC. Furthermore, polymethylol melamine is prepared from melamine and paraformaldehyde under mild conditions, resulting in low cost. The components of the present invention exhibit excellent synergistic effects, significantly improving the thermal stability of PVC. DETAILED DESCRIPTION
[0009] The specific embodiments of the present invention will be described in further detail below. For those skilled in the art, the above and other objects, features and advantages of the present invention will be apparent from the detailed description of the present invention.
[0010] Preferred preparation of polymethylol melamine: Polymethylol melamine is prepared by a nucleophilic addition reaction between melamine and paraformaldehyde. The preferred preparation process is as follows: 1 mol of melamine and 4 mol of paraformaldehyde (calculated as the amount of formaldehyde) are dispersed in water, heated to 70°C, triethanolamine is added, the pH value of the reaction system is maintained at 8.5, the reaction is stirred for 1 hour, and then the water is removed to obtain polymethylol melamine.
[0011] Example 1: The composite heat stabilizer of this embodiment contains the following components in mass fractions: polymethylol melamine: 50%; zinc stearate: 30%; hydrotalcite: 15%; and 1,3-dimethyl-6-aminouracil: 5%.
[0012] Example 2: The composite heat stabilizer of this embodiment contains the following components in mass fractions: polymethylol melamine: 40%; zinc stearate: 35%; hydrotalcite: 22%; and dibenzoylmethane: 3%.
[0013] Example 3: The composite heat stabilizer of this embodiment comprises the following components in mass fractions: polymethylol melamine: 55%; zinc stearate: 25%; hydrotalcite: 14%; and stearyl benzoyl methane: 6%.
[0014] Example 4: The composite heat stabilizer of this embodiment contains the following components in mass fractions: polymethylol melamine: 50%; zinc stearate: 30%; hydrotalcite: 15%; zinc acetylacetonate: 5%.
[0015] Example 5: The composite heat stabilizer of this embodiment contains the following components in mass fractions: polymethylol melamine: 50%; zinc stearate: 30%; hydrotalcite: 15%; calcium acetylacetonate: 5%.
[0016] Thermal stability test The performance of the composite heat stabilizer was tested using a Harp RM-200A torque rheometer under the following conditions: material temperature of 190°C, test load of 5 kg, and rotation speed of 35 rpm. The test sample composition was: 54 parts PVC (SG-3) resin, 1.6 parts composite heat stabilizer, 12 parts CaCO3, 5 parts CPE, 1.6 parts titanium dioxide, 0.2 parts pentaerythritol monostearate, 0.1 parts antioxidant 1010, 0.2 parts PE wax, and 1 part ACR. After mixing in the torque rheometer for 5 minutes, the sample was removed and tested for initial whiteness using a colorimeter. A separate sample was also taken to measure dynamic thermal stability time. The test results are shown in Table 1.
[0017] Table 1: PVC sheet thermal stability test results.
[0018]
[0019] The results in Table 1 indicate that the polymethylol melamine-based composite heat stabilizer provided by the present invention can effectively inhibit the initial coloration of PVC and exhibit excellent dynamic long-term thermal stability for PVC, making it an excellent composite heat stabilizer for PVC. Furthermore, polymethylol melamine is a low-cost raw material and is easy to synthesize.
[0020] It should be understood that although the present invention has been clearly illustrated through the above embodiments, without departing from the spirit and essence of the present invention, technicians in the relevant technical field can make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims of the present invention.
Claims
1. A polymethylol melamine-based PVC composite heat stabilizer, characterized in that: Contains the following components by mass: Polymethylol melamine: 40-60%; Zinc stearate: 25-35%; Hydrotalcite: 10-25%; Auxiliary heat stabilizer: 3-6%; The molecular structural formula of the polymethylol melamine is: , where x is 1 or 2, y is 1 or 2, and z is 1 or 2; The auxiliary heat stabilizer is β -diketone compound or 1,3-dimethyl-6-aminouracil.
2. The composite thermal stabilizer according to claim 1, characterized in that The polyhydroxymethyl melamine is prepared using melamine and paraformaldehyde as raw materials.
3. The composite thermal stabilizer according to claim 1, characterized in that described β - The diketone compound is dibenzoylmethane, stearoylbenzoylmethane, zinc acetylacetonate or calcium acetylacetonate.