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

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Discussion Overview

The discussion revolves around the differences between polypropylene (PP) and cast polypropylene (CPP), particularly in the context of their use as dielectric materials in coaxial cables. Participants explore the manufacturing processes, material properties, and applications of both types of polypropylene.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Exploratory

Main Points Raised

  • Some participants propose that CPP refers to cast polypropylene and inquire about its differences from standard polypropylene.
  • Questions are raised regarding the manufacturing process of CPP and whether it involves extrusion or casting.
  • One participant mentions that they have not encountered coaxial cables using PP as a dielectric core, prompting requests for specific manufacturer details.
  • It is suggested that there is little difference in dielectric constant between PP and CPP, with the coefficient of thermal expansion potentially having a greater effect on capacitance than the production process itself.
  • Another participant introduces the concept of cellular polypropylene, questioning if the CPP referenced in a datasheet is cellular rather than cast.
  • Links to external sources are provided to support claims about the properties and applications of CPP.

Areas of Agreement / Disagreement

Participants express varying views on the definitions and applications of CPP and PP, with some agreeing on the similarities in dielectric properties while others raise questions about specific applications and manufacturing processes. The discussion remains unresolved regarding the exact distinctions and applications of the different types of polypropylene.

Contextual Notes

There are limitations in the discussion regarding assumptions about the definitions of CPP and PP, as well as the specific contexts in which they are used. The exact manufacturing processes and their implications on material properties are not fully explored.

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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