What if the TPU material turns yellow?


TPU is favored by the rubber and plastic material industry for its excellent wear resistance, environmental protection, tear resistance, transparency, self-adhesive, elasticity, hand feel and other properties. However, TPU has a natural defect, that is, TPU gradually turns yellow over time. So what if the TPU material turns yellow?


1. Avoid direct sunlight. The storage area of polyurethane shall be cool and ventilated. TPU can be packed in plastic bags and placed in a place without sunshine.

2. Spray anti yellow paint. There are usually two forms of spraying, one is in mold spraying and the other is out of mold spraying. Apply anti yellowing coating on the surface of TPU finished products to form a protective layer to avoid pollution and yellowing caused by TPU skin contact with the atmosphere. This form is now widely used.

3. Add anti yellowing agent. In order to improve the anti yellowing ability of TPU products, special anti yellowing agents are often added to the raw materials, but the anti yellowing agents are expensive. When using anti yellowing agent, its economic benefit should also be measured. For example, our blackbody is not sensitive to yellowing, so we can replace the anti yellowing agent with cheaper non anti yellowing raw materials. As the anti yellowing agent is a raw material additive, it must be mixed with component A to achieve uniform distribution and anti yellowing effect, otherwise local yellowing will occur.

4. Use good mixing ratio. An appropriate proportion of liquid I and liquid p can achieve the most sufficient mixed reaction without incomplete reflection. When these phenomena occur, the hydrolysis resistance and yellowing resistance of the finished product will be greatly reduced, especially when the ISO ratio is too large, the yellowing of the finished product will be accelerated.

5. Avoid contamination during manual operation. Polyurethane (TPU) finished products will be polluted during painting or storage, resulting in yellowing, such as sweat, organic solvents, etc. Therefore, TPU products should pay special attention to the cleanliness of the contact and minimize the painting process.

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