This goes back to the American patent number about 50 years ago. 278973 1 and British patent nos. 8 13, 5 14, which were written by Leonard? 9? 9 Lawrence? 9? Two patents applied by Maraverno. He applied for a patent for Unilever's striped toothpaste, and its first commercial product was called Signal. The trick is that at the back of the toothpaste tube, there is an empty tube extending slightly inward into the toothpaste tube, so that white toothpaste can pass through this tube. This catheter is surrounded by a funnel-shaped neck of a toothpaste tube, and this catheter has some small holes leading to this funnel. When the toothpaste tube is filled with toothpaste, the red toothpaste is first squeezed into this funnel. When you squeeze the toothpaste, the white toothpaste will pass through the catheter and exert pressure on the red toothpaste, forcing the red toothpaste to enter the catheter through these small holes, thus forming color stripes.
Website: /bbs.php? Mode = theme & GID = 25. bid = 2008 1 10700294776