Plywood was invented during the Second world War but it was primarily used exclusively to build PT BOATS and Landing Craft for the military. After the war they began using plywood for residential construction and furniture but by the end of the 1940's there was a severe shortage of Lumber suitable for making plywood.

Particle board was invented in 1950 as a substitute for plywood but it didnt receive much public attention at first.

Formica had been invented in 1912 by alternately layering kraft brown paper or cloth and melamine resin. Initially it was used to make circuit boards for radio's until 1951 when they came up with the idea of using a finished design pattern on the top layer, which created the formica that we still use today.

It was quickly realized that particle board made a perfect substrate under formica to make counter tops or laminated furniture components.

I was born in 1947 and I can vaguely remember when public restaurants started getting the latest "space age technology" as they installed formica counters and table tops. In the early 50's most homes had huge wall mounted cast iron sinks in the kitchen, while some had built in cabinets with countertops covered with linoleum.

Only the very well to do could afford the space age luxury of built in cabinets and formica countertops.

Crude forms of plastics had also been developed during WWII but again, they did not receive much public attention until the mid 50's.

Primarily all they were making was "Cassein Plastic" which was a hard yellow translucent type of plastic that was primarily used to make insulated handles for screwdrivers.

In those days even toys were primarily made out of steel, die stamped tin, cast pot metal or wood. I can remember buying little cars and trucks in the 5&10 cent store that were being imported from Japan. We would often wear them out, then open them up to find labels on the inside of the tim, which revealed the toys had been made by die stamping old beer cans. (I have a small toy 1952 chevy that has a Black & White "Carlings Black Label" Beer label printed on the inside)

By 1952 or 53 we started seeing a lot of plastic toys, kitchen wares and crudely molded plastic flowers being imported from Japan. In those days the label "Made in Japan" was synonamous with cheap imitation junk, but from that humble beginning the Japanese have primarily taken over the industrial market of the world.

In those days the Japanese had a moto; "There is nothing under the sun, that we can't make at a cheaper price"

Now, getting back to your question, based upon the fact that your cabinet has both particle board and molded plastic parts I would guess its age as mid to late 1950's at best.