Spray Can Applicable Thermochromic paint
Q. I am doing layman’s research for a new product that would be sprayed onto typically plastic materials, and cause a change in color when that material comes in contact with another moving metal part. The change in color would need to be visible in daylight conditions to provide immediate short-term visible feedback of the previous contact between the metal and the plastic so the operator can make an adjustment of the metal material’s path relative to the plastic material. The color change would then need to disappear with the subsequent cooling of the plastic material back to room temperature. Contact with the moving metal part would cause a surface temperature rise in the plastic of ~5-10°C.
Although initially intended for commercial application in high-speed manufacturing, this would ultimately be a consumer product, preferably packaged in pressurized spray cans, encouraging mass marketing through retail outlets for maximum investor appeal.
What thermochromic products would you recommend that offer the greatest color change, and what would those colors be? What is the temperature change necessary to effect this color change? How long would the change be visible with unassisted air cooling back to room temperature? Are these materials safe enough for a consumer to apply outdoors without concern for exposure or inhalation hazards? Feel free to point out any homework I might need to do before asking these questions. L. C.
A. While it is true that I am a paint consultant, it is not true that I know everything. Although I worked with them in the laboratory, I know very little about thermochromic materials. Unfortunately, I can’t fully answer your first three questions. However, I can tell you that if you want to market a consumer product, it must be done in compliance with existing health and safety regulations. Therefore, your first homework assignment is to query spray can-paint suppliers about these regulations. Your second assignment is to determine if your thermochromic paint can be applied by spray can.
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