when did they start using plastic?

[Neon_WA]

picking up this nice early ALU from 1971 made me wonder when chip manufacturers started using plastic

Think I have seen some from 1970 but would be nice to see when they started to appear

[Robev]

Plastic encapsulation was first used around 1949. The documentation is a patent that was filed in April of that year

The P-DIP (Plastic Dual In-line Package) format was the most important breakthrough in the
entire packaging history, and is still the foundation of modern non-hermetic, low-cost packaging.
While it is difficult to attribute the DIP to a single inventor, the earliest patent found was filed in
1964 and was designed for multiple transistors rather than an IC (b). The DIP was there first low
cost plastic package that could be used with ICs and the flagship of the plastic package revolution
for many decades. The DIP, SIP and quad-type versions dominated the industry until the SMT
finally became the preferred style in the late 1980’s. But, from time to time, the DIP leads were
bent outward to enable SMT even before surface mount became popular. Texas Instruments used
this idea for their calculators some time in the 1970’s.

http://www.et-trends.com/files/Milestones_in_Packaging.pdf

[Neon_WA]

nice background

thou still interested when they commercially started to appear

[UMMR]

Hello,
interesting discussion!
The book "Microelectronic Circuits and Applications" by Carroll (it's in fact a collection of many articles appeared in "Electronics" and similar engineering journals), published in 1966, has a reference to a plastic DIP-like package developed for military use in 1963 by Fairchild.
With the help of the historical work of Khambata, "Introduction to integrated semiconductor circuits", I think the Texas Instruments' SN158xx DTL (1965/1966) was the first commercial logic family packaged in modern looking plastic DIP. The oldest non-TI plastic DIP I know is a Motorola MC8xx RTL, dated 1967, along with the long living Philips FC DTL series.
Paolo

[magictom]

Very interesting indeed!

Below are 2 examples of plastic DIPs from 1966 (Motorola & TI),
and a TI flat pack in plastic enclosure from 1962 (SN514)