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Mon, 14 Aug 95 14:15:21
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  This message is resent,.somehow it got sent before I was done..(monday's!)
  
  On 10 August 1995, Dougal Stewart wrote:
  
    >> We have a customer who has been asked by his designers to      
    >> provide boards with a CTI of greater than 400 and a flammability 
    >> rating of 94V-1. They also ask if standard FR4 will comply - at 
    >> least I know the answer to that one.
  
  
    >> I am not sure what laminate will meet this requirement - FR3 
    >> has been suggested, but laminate suppliers always leave off  
    >> the CTI when quoting electrical properties.
  
  
  Dougal,
  
     I sent a response Friday to the second-half of your post, but then 
  came across this message that I hadn't read yet. I would like to add a 
  little more to the post I made Friday to help make that information a 
  little more useful. 
  
     When you speak of CTI, I'm not exactly sure what is meant by that...I 
  don't believe it's coefficient of thermal expansion (CTE) because the 
  values are expressed in parts-per-million...and I can't think of why 
  anyone would want a laminate that has a CTE of 400 ppm anyway, so I'm 
  assuming what it is that you're asking for is laminate that has a glass 
  transition temperature (Tg) of 400 degrees F. or above...that works out 
  to 204.44 degrees celsius (400-32 x 5/9=degrees C.)...I'll list below the 
  important properties of the materials I refered to in my last email:
  
  
                      ** Reinforcing Materials **
  
  
                   Dielectric            CTE,ppm/degree C.
                    Constant
  Material           @ 1 MHz             Long.     Radial         
  
  E-Glass             5.5                 5.5       5.5
  S-Glass             4.5                 2.6       2.6              
  D-Glass             3.6                 3.1       3.1
  Quartz              3.8                 0.54      0.54
  Kevlar-29           4.1                -4.0      60.0
  Kevlar-49           4.1                -5.0      60.0
  E-PTFE              2.0                70.0     120.0
  
  
  
                          ** Bonding Resins **
                                                                Glass
                                                                Transition 
             Generic                        Dielectric  Loss    Temperature
Resin        Type             Supplier      Constant    Tangent (Degrees C.)

G-10FR       /FR-4             Norplex          3.6      .032        125 
RSM-1212     /FR-4             Shell            3.6      .032        125
Quadtrex 5010/Tetra.           Dow              3.6      .032        180
RSM-1151     /Tetra.           Shell            3.6      .032        180
G-200        /BT/Epoxy         Norplex          3.2      .012        185
BT2110F      /BT               Mitsubishi       3.1      .003        250
BT2060BG     /Modified-BT      Mitsubishi       3.9      .001        220
Kerimid      /Polyimide        Rhone Poulenc    3.2      .020        275
RSM-1206     /Polyimide        Shell             -         -          -
RDX 64826    /Cyanate ester-I  Interez          3.1      .005        260
XU-71787     /Cyanate ester-IV Dow              2.8      .004        260
UDEL         /Polysulfone      Union Carbide    3.0      .004        192
ULTEM        /Polyetherimide   General Electric 3.1      .0065       260

Notes: 

* All temperatures are in degrees C.)

* Tetra. is abbreviation for Tetrafunctional Epoxy

* BT is abbreviation for Bismaleimide Triazine, also known as Cyanate ester 

* RSM-1206 is usually provided as a blend with epoxy.

              
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