Zinc-based heat stabilizer for polyvinyl chloride, composition and application

Abstract

The invention relates to a zinc-based heat stabilizer for polyvinyl chloride, a composition and an application. The zinc-based heat stabilizer is prepared by using urea organic matter and zinc salt through liquid phase reaction. The composition prepared by the zinc-based thermal stabilizer alone or mixed with calcium carboxylate, β-diketone, phosphite and polyalcohols can effectively improve the thermal stability of PVC. The raw material of this zinc-based heat stabilizer is easy to obtain, the synthesis process is simple, it has industrial application prospects, and it also plays an important guiding role in the research and development of new urea heat stabilizers.

Description

technical field [0001] The invention belongs to the technical field of PVC (polyvinyl chloride) heat stabilizers, and in particular relates to a zinc-based heat stabilizer and a composition. Background technique [0002] PVC is one of the polymers with the earliest industrial production time and the widest application field in the world, and is widely used in various fields of industry and agriculture. However, PVC resin is also one of the polymers with the worst thermal stability and the most prone to degradation. It begins to thermally degrade at 120°C, releasing toxic gases (mainly hydrogen chloride), and the color of the product turns red until completely black. The mechanical properties deteriorate and eventually lose the use value, so this defect greatly limits the application field of PVC. In order to effectively avoid the degradation phenomenon of PVC in the process of processing and application, the more common practice in industrial production is to add PVC during ...

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Problems solved by technology

However, although the traditional zinc-based heat stabilizers can effectively inhibit the initial degradation and coloring, the conversion product ZnCl 2 It is also a catalyst for PVC to remove HCl, which will cause malignant degradation of PVC samples and make the material suddenly black, that is, "zinc burning". Therefore, the long-term thermal stability of traditional zinc-based heat stabilizers is relatively poor. Composite use of calcium-based heat stabilizers with good long-term thermal stability

[0004] Mohamed et al studied the thermal stabilization effect of a series of phenylurea and phenylthiourea derivatives as PVC heat stabilizers (Sabaa M W, Mohamed R R, Yassin A A.Organic thermal stabilizers for rigidpoly(vinyl chloride)VIII.Phenylurea and phenylthiourea derivatives[J].Polymerdegradation and stability,2003,81(1):37-45.Sabaa M W,Mohamed R R,Yassin AA.Organic thermal stabilizers for rigid poly(vinyl chloride)IX.N-Benzoyl-N′-p -substituted phenylthiourea derivatives[J].Polymer degradation and stability,2003,81(3):431-440.Sabaa M W,Mohamed R R,Yassin A A.Organic thermalstabilizers for rigid poly(vinyl chloride).Part X:N-acryloyl- N'-p-substitutedphenylthiourea derivatives[J].Polymer degradation and stability,2003,82(3):387-393.), the results show that when used alone for PVC thermal processing, phenylurea and phenylthiourea derivatives It can prolong the induction time of PVC thermal degradation, but it is not ideal in slowing down the HCl removal rate of PVC and inhibiting the degradation and coloring of PVC. If phenylurea and phenylthiourea derivatives are used in combination with zinc stearate, it will To a certain extent, it can not only increase the induction time of PVC thermal degradation, but also reduce the rate of HCl removal

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