Polycaprolactone?

[petergunn]

Is Polycaprolactone moulding plastic okay to use inside flashlights? :thinking:

Melting point is above ~60C (~140F). How hot can batteries/case get?

Seems to be quite easy to get (i.e. "Friendly Plastic" products) and might be useful for making custom battery holders etc.

-PG

 

[SilverFox]

Hello Petergunn,

Welcome to CPF.

In normal use the case of a battery rarely exceeds 100 F. However, if the light has been modified and is drawing higher currents, batteries can exceed 140 F and melt the plastic. This can also happen if the battery shorts out internally.

In non-use conditions, temperatures can exceed 140 F if the light is left on the back window shelf in a car with the windows rolled up in direct sun in the summer. Perhaps the plastic used in cars would be better suited to higher temperatures...

Tom

 

[Ragiska]

just because it melts at 140F doesn't mean it won't soften long before then.

 

[SilverFox]

Hello Ragiska,

It also doesn't mean that it will soften long before then...

Plastics can be manufactured and modified to exhibit a wide variety of physical properties.

Tom

 

[petergunn]

Hey Silverfox/Ragiska, thanks for the insight - didn't think about the car temps

Physical properties of Polycaprolactone:

• Inherent Viscosity (dL/g): 1.00 - 1.30
• Crystalline Melt Transition(°C) : 58 - 63
• Glass Transition Temp (°C) : (-65) - (-60)
• Solubility (at 5% w/w): dichloromethane + chloroform + hexafluoroisopropanol
• Density (g/mL) : 1.11
• Tensile Strength(psi) : 3000-5000
• Elongation (%) : 300 - 500
• Modulus(psi) : 3 - 5x10^4

I think its going to stay hard until at least 58C (136F).

That said, perhaps I might get some just to make moulds for something more durable (the moulds can be melted and reset any number of times) using something like epoxy putty which withstands 500+F and is readily available at a reasonable price :thinking:

-PG