| Recorded: |
March 22, 2011 |
| Presented by: |
Greg Fedor,
RTP Company |
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Do complex UL ratings and regulations covering flame retardant plastics have you scratching your head?
Then join Greg Fedor, senior product development engineer at custom compounder RTP Company, as he explains everything you ever wanted to know about flame retardant plastic compounds.
During this easy to follow webinar, Greg will cover how fire affects plastics and the protection FR additives provide, review available FR chemistries, explain how regulations impact FR product selection, Global FR test methods, including UL94, and discuss the various ratings that can appear on a “yellow card”.
Regardless of your knowledge level, Greg’s informative presentation is not only an introduction to FR technologies, but also a valuable update for those already well versed in the subject matter.
Questions & Answers
Q: Are there preferred colors, others to be avoided?
A: Natural color of most FR materials will be off-white, so they are readily colorable products. But, due to the FR content the base color can be difficult to get rich/dark colors (BLACK, BLUE, etc.) in some resins such a Polypropylene. Color is something that has to be addressed on a specific compound basis.
Q: What is the approximate cost of UL testing?
A: For RTP Company to pursue a simple UL94 horizontal or vertical burn rating the approximate cost is $4450. Additional heat aging or weatherability testing will increase this cost.
Q: What OEM restrictions are new for the automotive industry?
A: I am not aware of any FR restrictions within the auto industry specifically.
Q: What is red phosphorus? Is it considered more hazardous than any other type of phosphorus?
A: Red phosphorus is not an FR additive that RTP Company is actively working with as it does have some safety concerns with handling and processing.
Q: If you chose a resin with a poor flammability rating and already have a tool made and thus limited resin choices is there something you can do to improve the flammability characteristics? Change processing parameters to improve flammability characteristics?
A: Depending on the resin selected there should be a flame retardant version that could be formulated and produced. The flame retardant additive will have little to no effect on shrink rate and therefore could be molded in the same tooling. Processing adjustments will not be able to influence the flammability characteristics inherent in the material.
Q: Have you had any experience combining FR additives to PLA?
A: We are currently exploring the use of FR additives in conjunction with compounds with PLA content. We do not have anything commercialized at this time.
Q: Isn't there a 5V UL flame rating too?
A: Yes, the 5V testing is a two-fold test that is commonly required of electronic enclosures. There is a vertical burn test and an additional panel burn test associated. The 5VA rating requires material to pass both tests, while the 5VB rating only need to pass vertical burn portion.
Q: Can RTP Company conduct RTI testing in house?
A: RTP Company would be able to do some thermal aging in house for screening, but cannot perform the official UL RTI testing for acceptance by UL.
Q: What majority of these plastics are FDA aprroved, BPA free?
A: There are no FR additives that are currently FDA approved, so we will not be able to provide a FDA FR compound. We can provide BPA free products.
Q: What in the chemical/polymer structure causes "inherent" flame resistance
A: Some of the inherently flame retardant resins contain chlorine and fluorine in the polymeric structures which create the ability to self-extinguish. The other high temperature resin systems (PEEK, PEI, PES, etc.) polymeric structures consist mainly of ring systems which retain their structure more readily under heat and tend to form a protective char network when exposed to flame.
Q: How do we test fibers?
A: Fibers would be difficult to test and quantify any flame testing results as is. A better approach would be to fire test the finished article.
Q: Any FR for clear PMMA?
A: We do not currently have any options for clear flame retardant PMMA.
Q: Do tool steels need to be better/different quality to handle FR additives?
A: FR additives tend to be corrosive; therefore the selection of tool steel is important. Selection to prevent corrosion should be Stainless Steel, Chrome or Nickel Plating. During extended periods of shut-down or storage, molds should be dismantled and cleaned, then coated with a neutralizer and dehydrator containing a rust inhibitor. Corrosive vapors which could cause severe mold and equipment corrosion consist of a degradation mechanism which is very time/temperature dependent.
Q: Are some FRs better for use in hot runner systems?
A: FR's in hot runner systems follow very similar paths as a cold runner system, with the exception that the results are accelerated do to the residence heat and stagnant areas that may occur in a hot runner system. The systems should be designed for the application and cavitations of the desired mold in mind. Hot runners or manifolds should be constructed of similar tool steels to prevent corrosion (i.e. Stainless Steel, Chrome or Nickel coatings); they should be constructed to have very minimal residence time or chamber storage. During any period of shut down they should be completely disassembled, clean and coated with a neutralizer and dehydrator containing a rust inhibitor.
Q: How is HB-specimen marked (at 25 and 100 mm) in a way that it doesn't affect the flammability result?
A: A simple mark with pen/marker on the surface will not influence the results of the testing
Q: Any about transparent matters?
A: Transparent FR Polycarbonate options are available.
Q: If we add color pigments we will loose the UL-listing and we will have to apply for a UL-listing for the particular colors again? How do we get an "all color listing"? What colors do we have to submit for that listing? Will our company be the UL certificate holder?
A: As a raw material supplier we can submit for ALL COLOR listing where we would hold the certificate and can provide any color requested under that certification (as long as within UL pigment limits). The other option would be to UL list a material in conjunction with MB for coloring. If any coloring is done at the press without a UL approved MB, the UL listing will be void.
Q: How do you know from a yellow card which outdoor test was passed when 'f2' is listed? UV or Immersion?
A: Information for this would be kept in the raw material suppliers UL file.
Q: Can RTP do UL Flame Testing of end product samples vs just plaques?
A: RTP can do screening tests as well as other analytical testing to confirm a part is flame retardant. But, unless the part is large enough to cut flat 125mm X 12.5 mm specimens at uniform thickness, we cannot do testing in accordance with UL94. |
