The question seems to inquire about the material or product specification related to "20th Century Plastics." It appears to be asking if a particular stock or product, referred to as "TL-20," is made from PVC (Polyvinyl Chloride). Without specific details about the "TL-20" designation, it's challenging to give a definitive answer. However, 20th Century Plastics was a company that likely produced an array of plastic goods, potentially including items made from PVC, which is a common, versatile type of plastic widely used for various products due to its durability and flexibility. It's important to check the product specifications or contact the manufacturer (or their successors, if the company has since been acquired or undergone a name change) for precise information regarding the material composition of the TL-20 product.

[The drying time for PVC cement can vary depending on factors such as the brand, pipe diameter, and environmental conditions. Generally, it sets enough to handle within 2 minutes to 30 minutes but can take up to 24 hours to fully cure and achieve maximum strength. Environmental conditions such as temperature and humidity can significantly impact drying times; warmer, drier conditions tend to speed up the process, while cooler or more humid environments can prolong it. It's crucial to follow the manufacturer's instructions for the specific cement you're using and to allow sufficient drying time before subjecting the PVC joints to any pressure.]

Polyvinyl Chloride (PVC) cables are generally not inherently UV resistant. PVC material tends to degrade under extended exposure to ultraviolet (UV) rays, resulting in discoloration, brittleness, and ultimately a reduction in the material’s mechanical and insulation properties. However, many manufacturers add UV stabilizers to their PVC cables to enhance their resistance to UV radiation, making the cable more suitable for outdoor applications. These stabilizers absorb or block UV radiation, thereby protecting the cable from the harmful effects of the sun. It’s essential for consumers to specifically look for UV-stabilized PVC cables when they require solutions for outdoor use to ensure longevity and reliability of the cables in such environments.