What is the difference between PP(polypropylene) and CPP?

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SUMMARY

The discussion clarifies that CPP stands for cast-polypropylene, which is utilized as a dielectric material in coaxial cables. Both PP (polypropylene) and CPP are fundamentally the same material, with negligible differences in dielectric constant. The coefficient of thermal expansion significantly influences capacitance more than the production process. The manufacturing of CPP typically involves an extrusion process, which allows for tighter tolerances compared to simple extrusion methods.

PREREQUISITES
  • Understanding of dielectric materials in coaxial cables
  • Familiarity with polypropylene (PP) and cast-polypropylene (CPP)
  • Knowledge of extrusion processes in manufacturing
  • Basic concepts of dielectric constant and thermal expansion
NEXT STEPS
  • Research the properties of dielectric materials used in coaxial cables
  • Learn about the extrusion process for producing CPP
  • Investigate the thermal expansion effects on capacitance in dielectric materials
  • Explore the differences between cellular polypropylene and cast polypropylene
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Engineers, materials scientists, and professionals involved in cable manufacturing and design, particularly those working with dielectric materials in coaxial cables.

Tae Hwan Kim
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To my knowledge, CPP means cast-polypropylene, which I've seen used in a coaxial cable. Some cables use CPP as dielectric material. My question is:

1. what is the difference between PP(polypropylene) and CPP?
2. How is CPP made?
3. Is the permittivity and loss tangent of CPP different from that of PP?

thank you. :)
 
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Tae Hwan Kim said:
I've seen used in a coaxial cable.
What manufacturer and part number?
I'm familiar with PE and TFE, but have never seen coax using a PP dielectric core.
 
Asymptotic said:
What manufacturer and part number?
I'm familiar with PE and TFE, but have never seen coax using a PP dielectric core.
here it is:)
 

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Baluncore said:
CPP = Cast PP
https://www.mitsuichemicals.com/film_cp_cast_polypropylene.htm

There will be little difference in dielectric constant between PP and CPP. They are the same material so the coefficient of thermal expansion will have a greater effect on capacitance than will the production process.

thank you sir :)
 
A manufacturer makes PP core coax cable ...I learn something new every day. :)
 
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Considering they produce 5km reels this must be done with some type of extrusion process. Casting a 5km part would be difficult to put it mildly.

http://www.profol.com/en/about-cpp-film-faq.html

Based on the information linked above I would guess that there is a post extrusion sizing and cooling die to maintain tighter tolerances vs simple extrusion.

BoB
 
Cellular polypropylene, CPP, with a dielectric constant of about 1.3 is used as a dielectric in some data cables.

Google Books.
Cable Engineering for Local Area Networks. Barry J. Elliott. Page 94.
 
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Baluncore said:
Cellular polypropylene, CPP,

So is the CPP in the datasheet probably Cellular not Cast?

BoB
 
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