UV absorbers can absorb the energy of ultraviolet rays and convert it into heat for release, preventing the PVC molecular chains from breaking due to the absorption of ultraviolet rays. For example, benzophenone - based and benzotriazole - based UV absorbers can effectively reduce the damage of ultraviolet rays to PVC materials and significantly improve the weather resistance of the materials in outdoor environments. Generally, the addition amount is between 0.1% and 3%.
This type of stabilizer has functions such as capturing free radicals and decomposing peroxides, which can effectively inhibit the photo - oxidative degradation of PVC. Adding an appropriate amount of hindered amine light stabilizers to PVC can greatly extend the service life of the material. The addition amount is usually 0.1% - 1%.
Such as phenolic antioxidants, they can react with the free radicals generated by oxidation in PVC materials to terminate the free - radical chain reaction, thereby delaying the oxidative aging of the material. Common ones include antioxidant 1010, etc., and the addition amount is generally 0.1% - 0.5%.
For example, phosphite - based antioxidants can decompose peroxides and work synergistically with primary antioxidants to improve the antioxidant effect. When used in combination with primary antioxidants, secondary antioxidants can better improve the weather resistance of PVC materials. The addition amount is generally equivalent to that of primary antioxidants.
They have good heat - stabilizing effects and can prevent PVC from decomposing due to heat during processing and use. However, due to the toxicity of lead, their application is limited to some extent.
They have excellent heat - stabilizing properties and good weather resistance. Among them, mercaptan organotin has little initial coloration to PVC and good long - term heat stability, which can effectively improve the performance of PVC materials in outdoor environments. The addition amount is generally 0.5% - 2%.
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Calcium Carbonate: Calcium carbonate is a commonly used filler. Appropriate addition can improve the rigidity, hardness, and dimensional stability of PVC materials, and also improve their weather resistance to a certain extent. Generally, calcium carbonate with a smaller particle size and good surface treatment is selected, and the addition amount is between 5% and 30%.
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Titanium Dioxide: Titanium dioxide is not only a white pigment but also has a good ultraviolet - shielding effect. It can reflect and scatter ultraviolet rays, reducing the penetration of ultraviolet rays into PVC materials, thereby improving the weather resistance of the material. The addition amount is usually 1% - 5%.
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Amount: Plasticizers can increase the flexibility of PVC materials, but excessive plasticizers will reduce the weather resistance of the material. Therefore, it is necessary to reasonably adjust the amount of plasticizers according to specific usage requirements to improve the weather resistance while ensuring the flexibility of the material.
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Type: Select plasticizers with good migration resistance and light resistance, such as trimellitate - based plasticizers, which can reduce the migration and volatilization of plasticizers in outdoor environments and improve the long - term weather resistance of PVC materials.
During the processing of PVC materials, excessively high processing temperatures and overly long processing times can cause material degradation and reduce its weather resistance. Therefore, it is necessary to strictly control the processing temperature and time to ensure that the material does not undergo excessive degradation during processing. Generally, the processing temperature of PVC should be controlled within an appropriate range to avoid excessively high temperatures.
Blending PVC with other polymers with good weather resistance, such as blending with acrylate - based polymers, can improve the weather resistance of PVC materials. The blended material combines the advantages of the two polymers, improving the performance of the material in outdoor environments.
Coating a protective coating, such as an acrylic coating or a silicone coating, on the surface of PVC materials can effectively block the intrusion of ultraviolet rays, oxygen, and moisture, improving the weather resistance of the material. The coating should have good adhesion, water resistance, and ultraviolet resistance.
Treating the surface of PVC materials with a surface treatment agent, such as using a silane coupling agent, can improve the surface performance of the material, enhancing its weather resistance and water resistance. The surface treatment agent can strengthen the isolation effect between the material surface and the external environment, reducing the erosion of environmental factors on the material.
