Contradiction matrix: Striped toothpaste

Let's see how we can spot TRIZ in action in the invention of the humble striped toothpaste!

Squeezing toothpaste out seems like a simple act, until one thinks about how the stripe is maintained perfectly when squeezed out of a tube without looking like a mess of colors.  

From TRIZ's contradiction matrix, let's choose "Stability of the object's composition" as the improving feature, as we want to make sure the colored and white paste doesn't mix.

And then we choose "Device complexity" as the worsening feature in the TRIZ contradiction matrix as we want striped toothpaste from a simple toothpaste tube, cheap to make and not complicated like an ice cream maker machine.

The matrix suggests 4 principles:

Principle 2: Extraction, Separation, Removal, Segregation

Principle 35: Transformation of the physical and chemical states of an object, parameter or properties change

Principle 22: Convert harm into benefit, "blessing in disguise"

Principle 26: Copying

Here's an early patent for producing striped toothpaste called "Striping dispenser" filed in April 23, 1957!

 

The white paste or base material fills most of the tube towards the tail end. Colored paste fills the head end but stopping just before the thin pipe (48). Any pressure exerted on the tube will push the white paste through the thin tube, but at the same time push the colored paste through tiny holes on the thin pipe. An interesting point is that the white and colored paste does not need to be in separate compartments as they're thick enough to not mix.

Based on this design, there is certainly a large element of principle 2, where the colored and white paste is separated. Principle 22 also features prominently as the action of pushing the paste out of the tube from the tail end makes the invention work, as opposed to squishing the paste together into a mess (blessing in disguise). 

But what about principle 35 and 26? I'll leave that interpretation to you...