[78-L] Pressed in WHAT material...

[Kristjan Saag]

Royal Pemberton wrote:

> Polyvinyl chloride was developed in the 1930s, and was used for pressing
> transcriptions almost immediately.  It wasn't used for commercially 
> released
> records until the late 1940s.
---
A little bit of chemistry, here:
Polyvinyl chloride was discovered as early as in the 1830's and rediscovered 
a few times before anyone managed to make gramophone records of it.
The plastic was even in production in the 1920's but it was hard and brittle 
and both the B F Goodrich Co and Union Carbide & Carbon experimented how to 
make it elastic. Waldo Semon of the Goodrich Co succeeded in 1926, but it 
wasn't his discovery that became important for record production (which is 
often claimed, his soft plastic was used to coat shower cabin curtains etc). 
It was Joseph G Davidson of Union Carbide who developed the elastic gummy 
mess suitable for discs. This was done by creating a copolymer of vinyl 
chloride and vinyl acetate. Which was introduced as Vinylite.
Most PVC produced worldwide today is in its homopolymer form. So the correct 
chemical abbreviation for the copolymer compound you find in your Perry Como 
LP's is PVCA.
So we'd better keep calling them just "vinyl records". Which would include 
even the Victrolacs (a vinyl compound, according to Edward Wallerstein, who 
developed the 1948 vinyl record) and the polystyrenes.
What I'd like to know, though, is in what way the RCA compound differed from 
the one used by Western Electric for its radio transcriptions and by Muzak, 
who was also among the vinyl pioneers. Who was using Vinylite and who 
wasn't?

Kristjan