Hmm, so basically it's a heated syringe? Is there a reason you couldn't just use a regular syringe and heat it up?

A lot of diy/custom lure makers are are already doing something very similar.

The process involves a plastic mix called Plastisol https://en.wikipedia.org/wiki/Plastisol which is initially liquid but after heating it for the first time and letting it cool it becomes rubbery.

In small scale setups the heating is typically done in a glass beaker and microwave or other heater. Injection is done using giant metal syringe (which are sold for exactly this purpose).

If you look up some videos of people doing it the process is quite messy. Search "making soft plastic lures" on youtube. Looks like this product just tries to streamline the process by integrating syringe, heater and mixer (typically you would mix in a dye and or glitter preferably without introducing a lot of air bubbles), while at the same time comparing their product to everything else except the direct competitors based on similar technology.

Considering the target audience (a lot of fishing lures) and information about their plastic/rubber - initially liquid, needs to be heated to ~180℃, becomes rubbery after cooling, recyclable seems likely that the rubber they are using is very similar to the plastisol stuff.

The recyclability claim is a bit weird. Yes you can remelt that stuff, which is not a problem if you heat it in a pot. Not sure how well it would work with their product which has the heater integrated and relies on the rubber initially being liquid at room temperature before the first heating so that you can suck it into syringe.

Using PLA molds also seems a bit of stretch. While their heater can be set to lower temperatures, the existing plastisol requires ~180℃ and screen in their own videos are showing similar temperature. PLA is melting temperature is ~210 and it becomes soft at 60. Might get away with PLA mold for some shapes once or twice. Maybe not so bad if it cools fast enough and actual melting temperature is lower than 180. In most of the lure making videos I have seen they are usually using aluminum molds.

The Kickstarter video shows temperatures of 180°C, and polypropylene syringes don't support that. You can probably use a glass syringe but I suspect that would gum up quickly.