CA2016366A1 - Insulating electromagnetic shielding resin composition - Google Patents

Abstract

ABSTRACT
Filler blends of electroconductive particles with electrically non-conductive particles are provid-ed which are useful in making electromagnetic shield-ing resins for encapsulating electronic devices.

Description

. .

2~63~6 , .1 , IN~ilJLATX~ ~LECTROMAG~ETIG SHIELDI~
RESIN ~O~'OSITInN

~ his ~nven~n ~ ~llr~ct~d ~o a filler bl~nd 5 fo~ n~akir~g ~ trom~gn~tl~ ~h~eldln~ r~in~ w~ich ~re ~ct~c~lly r~on-condu~ve ~nd which a~@ p~rt~cul~rly u~e~ 8 co~n~ n~ps~ n~0 ~
~ounted and ~xi~l 1B~d~t ind~c~or~. Sp~lfi~ally, ChB
in~n~lon 1~ t~r0ct~d ~o a fill~ blend ~ 8~E!lt8n 10 ~i~lly ~iphe~e~l el~ctrocon~uctiv~ p~ ele~ rld ~lsc~rlcally non~condu~iv@ par~icleQ in ~ z~
r~ng~s ~n~ ~rolume r~tio~ æuch ~h~t ~h~n c~b~n~d ~ h 2n eLect~ically ~on~c~nduc~iY~ r~a~n b~nd~rg ~o~
an elect~i~ally ~on~conduc'c~ ncap~ul~ or co~n~
1~ with ~ ero~a~tiotic ~h~ldin~ prop~t~s~, Cert~in ~ troni~ ~ompoT~er~ r~
~lec~o~nagslet~c ~h~eldin~ ~o pl~c~ ttl~m ~n ~lo~
p~oxlP~ y ~o o~h~r ~omponent6 on p~n~d C~U~
~oard~ o~ever, ~uch ~omp~nent~ mu~ be ~l~cer~slly 20 ~n~ulAted f~om ~h~ u~F~undl~ ncludlng co~e~
lea~s ~d ~'ch~r con~Ctin~ port~on~ of ~h~ inti~ldu~l co~pon~n~ whlch of~n mu~t b~ ~le~ri~ally ~ol~d from ea~h ~th~r and &~nno~ conk~ w~h ~n~
ng m~e~i&l.
n~g, ~ 8 191~\W lla~t~Ol~
pli~ed l~y ~ p~e~e~ iron ~hl~lt whi~h ~ncompa~ ho dev~c~ T~t~ d ~ y ~o~
from ~h~ e ~nd oth~r c~mpo~en~ ~n th~ c~r~ul~.

30 I~ ~o~Lt~
Dod~e No . 1~24A

, . 2~163~6 ~;uch ~ .ce~ ~re rel~t~v~ly l~r~a in ~g 8n~ req~
additivn~l proc2e8in~ p~ ~:o ~ru~t1læe.
~ he ~omp~tlons provided ~n ~h~ p~ent invent:lon ~llow r~or ~lhe ~ncap3ulatiorl o ~n~u~tos~ d o~h~r ~ o~ b~h ~ n~
parti~ e elec~con~u~l~lvç p~rti¢le~ o B~ 8~arl-pherlC!Rl cr~ ti~ ola~d ~ ach o~&h~r by electri~lly slos~orlduct~vP- p~a~ti~le o~
~ub~tar.t~ally sph~xic~l ~ro~ ect~o~. Th~ re~ c~r lû b~ ~ppl~d di~e~ly ~o t~le ~nduc~or de~ b~u~e i'c ha6 acc~p~ble ~lectr~l in~ul~tlng ch~r~ct~ri~ic3 at moder~te to 1DW volt8~6~3. The U~ of ~h~ ill~d resln ~n the ~nu~ctu~e o~ ~hlold~d de~ic~ ha~ ~he net e~ect of ~educin~ ~h~ size Rnd ~e~h~ o~ ~h~
~hi~ld~ lndu~tor packsgQ ~nd pel~lli~CB ~h~lr u~ in a ~or~ co~p~c~ cir~u~.
It i~ th~e~o~e ~n ob~c~ o~ ~h~ ~nv~n~lon to provlde a flller blend for m~clng ~lecl:ro~agnetlc ~h~eld~ng r~ 6 whl~h co~prl~o ~0 1~) 8 to 55 po2~en~: ~y ~ol~e o~ c~o~
cond~ v~ cles o~ t~nt~lly sphe~lc~l cro~ ct~onal d~ lon w~eh ~ p~r~i~le Isi~ rsn~in~ ~rom 2S O . 5 ~o SO mlc~on~ di~ , and ~b3 ~lo~:tri~ nDn~conducti~re p~ lo~
r~g~ p~ n~ ~
O ~ 005 to ~ m~cron~ ~n d~ te~

3~ .
I~ ld ~ c~ o ~e ln~tl~n ~o pro~id~ ~or ~n el~ronl~ oo~p~nent p~lCk8~ ¢~mpo~l-~ion ~omp~J.~in~ ~ un~f~rm mis:ture o ~ blnd~r r~in with f~ 30 ~co ~0 p~c~n~ l~y volu~e o;e ~ r bl~nd 35 e~p~

~16366 ~) B ~o 55 pe~cer~t l~y volu~ o~ ~lL~2tro~
~orl~u~tilr~ p~ cl~a3 o~ ~ubat~ng~lly ~ph~ric~1 cr4~ c~ion~l dimerJ~Iion ~l~h ~r8g~ pa~ le ~ r~n~ing ~rom 0 ~ 5 to 50 ~ic~o~B iT~ d~a~m~t~, and ~b) elee~rlc~lly r.or.-~ondll~ti~e p~tlcl~s o ~e~ e part~cl~ e r~n~ng Prom 0.00$ to 2 ml~ron~ in diam~tQr, 1~
The lnven~on ~130 ~ncludea L~n elec~ro~lc d~ ld~d ~y ~n efe~tlve ~moun~ he p~ot~c~
~ve el~ctr~n~ ~hield~n~ pa~ka~ng r~ein, A~ ~nde~ re~ s m~y be 6~mploy~d emg 15 tri~lly non-con~ ive thærmopl~ ho~mosaetin~
~e~ln wh~ch c~n be fo~n~ d w~th th~ ela¢tron~aRn~tic er ~lend wiehout destroy~ th~ ect~e dl~t~i-bu~ion o:E ~lectrom~gn~ p~ les a~d ~n~ula~or p~ cles. Su~h ~ins m~ ln kh~ ~rm of ~ta ~0 ly2~t ~old~r~g ~o~po~ d~, ~e~¢tlon iL~ .t~ in~
~nd ~he~o~ c r~sis-~.
~ der 2~e~1n0 m~y b~ ~lo~ed ~ro~ poly~
epoxldo~, polye~ti~r~, polyur~hane~ 9 poly~o~yanu-r~te~, polya~ide~ ~ pPlye~ r~liEorleQ, poly~ld~s, ~nd ~5 mis~l;Ur~ ~h~r~o~. Re~in8 which are r~etlon In~ct~v able ~y b~ ~ele~d rom el:hylen~c~lly un~tt~ eed poly~e~s, ~r$nyle~ p~lye~r ur~h~ne~, 2~:hyl ~eS~ ry~ , v~y~ao/:y~n~ han~, poly~pa~le3, r~ylorL~ ~nd ~lerld~ 'ch~r~o$. ~h~o~l~st~e 30 blnde2~ ~n~ de polya&~yl~ea, poly~sg~n~s po~g~inyl ~hlori~e~, pv~y~lriyl iCl~o~ld~, poly~h~lon~, p~ly~
propylen~, ~n~ polyt~tra~luoro~hylen~ re~ln~
con~ rub~r~ ~uch ~ polyd Lmethyl iloJt~ r~
~l~o ~ u'l~ SuGh r~in6 wh~n fully cur~d h~v~
35 ~olum~ re~.L~ y ~ B~ 1 X 1~1O ohm~cm~

... .
- ., ~ . _1 l I ' . L I-ll.'l-l, ~ 1 I tL I lI I: ~i .L ~' . -il-l, i /.. ::J hi J.:'.J ~Ji J

~ pse~ntak~ p~ly~poxlde9 ~ri~ re~ on produ~t~ of dl~lyc~yl e~hi~rs o~ ~isph~nol A oa: ~r~301 novol~c~ w~thi v~ouæ cl~ , polyol~7 ~:lo~n~t~d po~yol~ th~ lik~ ln the pr~ai~n~e of ~ e~aLly~
S ~ h ~8 a bsr~n ~ri~luori~ ~min~ &o~plexl Rep~en~
~a~i~e ~f ~uch ar~ ~hose ~slec~d ~om '~rdu~a" X
sv~ ble :~ro~ ~hell Ghemic~l Company wh$~h i~
ldyl e~e~ prodllc~d by r~Qc~in~ epich~rohydr~r ixtur~ of ~ur~e~d~ ~lg~ly br8nahed malnly 10 tert~ m~no~ xyl~ ld~ h~ ng C~5 Clo ~nd Cll ~h~in len~h~ t"V~s~tlc" ~id~ enepoxy" M205 ~hich i5 ~ mo~ d dl~ly¢ldyl ~he~ ~ bi~ph~ ol A, Av~
bl~ ~o~ G neral M~ nc. 5 9'~pon" ~1~, w~lch iB
diglycidyl ~ther o~ glycer~ v~ bl~ ~rom Shell 15 Ch~mic~l ~omp~y~ "Epon" 826 whi~h ~ c%n~ lly pu~ d~glycidyl ~her of b~pherl~l A~ o a~ ble ~rom Sl~ell ~he~le~l ~ompatly~ ~nd "Epon" ~28 ~hich 1B 1~
h~ly ~e~inii~ o~m o~ l'Eponll 826, ~ r*m Shell ~h~cal ~o~2pa~y, A pr~e~d r~sî~ ~ d~ t 20 from ~plchlorohydr~n ~n~ or~o~ no~ol~ç pracur~o~
ECP~-~B60 ~v~llabl~ f~om Cib~ gy Co.
Al~o ~nclud~t ar~ ~el~mine ~ormald~hyde re~i~s wh~ch r~fe~ to ~ho3e ma~e~ial~ ~hi~h ~r~ ~oll known ln ~he art sn~ pr~p~ed by ~ea~ing mel.~ine and ~5 formald~hyde~ 2~odlfi~d ~el~m~ne or~Aldohyde $~o~ns ~u~h ~ alkyl~ed m~l~min2 f~ 1dQh~d~ r~ $nclude yl~t~d mel~in~ fo~ hyte ~in~3 R~p~o~n~d ~el~m~n~ f~m~ald~hyds ~ w~ ~a~y b~ ~3mploy~
~Ln~-lu~ or ~æ~mpl~ ~uch ~ rcially ~v~ bl~
30 ~e~n~ ~18 IlC~lol" 300, "l~ l" 301 ~nt ~Cy~el" 303 ~11 of w~ich ~re av~iLl4~ ro~ ~es~a~ Cy~mid~
l~p~l~y.
Polye~r~ a~e~ pria~a~ly polyRs~r~c~tion pro~ucts o:E un~tur~ed di~ oxyllc scids ~n~ polyhy-~5 dr~ c ~l~ohvl~ hsv~n~ 2~26 ~a~bon ~o~ anthyd~oxyl ~ollps ~x~pl:Lf~d ~ p~l~ols ~uch . , .

!

6 ~ S 6 ethylene E~ly~ol, dle~hylene ~lycol, p~opyl~ne ~lycol diprDpylene glycol, glyc~2~01~ pent~erythit~ o~bi-tol, lP8nnitol~ ~orbi~n, ~ry~lsol, ~i~pt;~rlol A ~nd m~t p~e:Ee~bly, ~lko~cyl~d de~ rattv~R 9~ 2, 2~di-5 ~4~ydroxyph~nyl)propane ha:vln~ ~ ~A-Ige of 2~2~ ~noles o~ e~hyl~sle o~ o~ p~opyl~ne ~x~d~ pQr ~ol~. Th~
dl¢ar~oxyli~ ~cld fn~y b~ ~s~ura~ad dica~o~yli~ ~cid ~uch a~ furnar~c and T~ ram~ c ~ h ~2s ph~hl~ , te~phthal$c~ l~oph~h~llc or al~phstle 10 df ~ xyl~ id~ h ~ ~u~cln~, a~ipi~, ~ub~ri~ 9 ~zelalc, a~b~c, t$~ehyl su~ç~ te ~n~ ha~o~ e~
d*~ o~ ch~ c~ su~h ~B te~chloro phth~l-ic sçid, Polyes~er ~e~ h~ving ~ so~nin~ po:~nt in the ran~e o 75-120C h~ve ~en four~d ~o be p~ cu-.15 1~ eful 1~ b$nd~r ~ln~.
Poly~ocy~nurl~ re~ln~ ~r~3 us~l~lly ~onO~nl3r so1u~ions of i~ocyAnura~e b~sQd ~n ~olu~n~ di~ocy~-naee ~nd hydroxyp~opyl ~neeh~ryl~ which ~r~ 401~1 1n a~ lea0~ on~ o~ ~h~ f~11s~n~ e ~ic~l poly~
~0 ~er~æ~ble e~hyl~n~c~1ly un~aSur~t~ ~or.omer~ ~uch ~B
yl ~n~ 9 ~y:re~ ~y~ yl~o~ yl ~e~h~c~yl~ hyl~cry1~e, ~hy1 me~h~c2~y1~t~, ~vethylh~x~l ~cryl~t~, 2~thylhe~yl ~th~rylato, bu~yl~c~yl~te, bll~yl m~h~crylEI~e, t~tra~hyl~n~
25 gly~o1 d~cryl~e, ~rimekhylol prop~ne ~rl~cry1~ ~, penl:~ery~hito1 t~cryl~Lt~ eop~nta~lyco1 di~cr~1st~, 1,3-bu~y1~n~ ~ly~ol dlac~yl~e~ d~br~ p~opyl~
~ory1~, 2,3~dib~ pr~pylm~th~ 4~ ycloh~r1 a~ryl~t~, ~y~loh~xyl ~ ha~ryla~ yli~ ~o~Ld, 30 m@th~ryli~ , hytroxy~t~yl ~ , hy~oxyotlhyl m~th~cryla~e ~ h~o~yp~opyl ~yl~e, hydr~x~propyl ~etha~ryl~e~, ~hïoroatyrene 7 acrylorlitrll~ n~llyl~
dene chlo~e, virlyl ~ , vinyl ~te~r~e, vlnyl ~col~n~ 7 hexan~ dLol d~a~yl~t~, h~xan~ dlol d~h-35 ac~yl~t~ ~Ttd ~n~xtu~ hereo~.

~ acki~n in,~ ~ol;ab~ oldin~ proc~ bl~
polym~r3 o~n b~ d ~ b~rld~r re~in~ For gx~apl~, un~ r~t~d poly~ter~, 1am~ ~e~:~rdant ~ tur~ted poly~ r~ ~n~ po~ echan~ e u~ful ~nasr~s ms~e~i~
5 ~1 for ~lectr~ net~c ~h~eldirl~ na~t~ inyl ~so~y~nur~, howe~ , o~fer~ high ~p~rae~lre proport~ee, corr~ioll ro~ n~e ~nd d:Lm~n3~0nal ~ta~ cyO Vlnylmal~tP ur~.thsnæ~, $1~m~ ~ets~d~nt rr~ n ~e~st~n~ po~ r~n~ ~A~
10 R~in~ n ~l~o ~e u~ed a~ bln~er mats~s~ m~ al~
~or the inv~n~i~n. In ~ti~lon~ ~he ~r~kan~ Vinyl-r~ by Dow G~e~icals carl ~e ~mploy~t~ R~l p~o~
~ble ~pox~eæ, pol~e~hy~ h~cryl~t~ ~nt tho nylo~
sre other candid~te~ ~or ~r~x ~ind~r r~B8~n9.
15 Poly~e~ ~lloys or bl~nd~ srQ other cl~ o 1~ABt/3 als i~o~ ~he m~trix ~at~rial, For ~smplæ~ alloy~ o~
un~tu~ted polye~ /vinyl~s~:ers ~nd pol~r~h r.
- of v~riou~ ~o~pofil~ions ~n be ~i~ren ~ ran~e o~
:~ properti~s ~ discl~ed in ~u~chin~on U.~O ~t~n~ No.
2~ 3, ~0~, 7~ .
g~ly~ a pr~pol3n~eY~ wh4~h ~ro r~act~o~
p~odu~ o~ a~ methyl~ cos~po1ar.ds ~l~h ~
~; imidl~ or tlam~neQ wilth ulai~i¢ n~ydr~d~ ar~ ul or ~n co~n~lorl wI~ch poly~ on~ os poly-25 ~h~rsul~one~. 5uits~1e ~o~a~ic poly~th~r~slon~ a~
b~r, er re~ns ~re tho~e whlch ~r@ lin~r polymer~
n~nin~S thr~ k~nd~ o~ unit bon~s ¢onqi~:in$ o~ ~n ~ylene b~d, ~n ~hæ~ bon~ ~nd ~ sul~o~ ~o~d. ~ush poly~ther3tl1on~ ra~in ar~ 8~ 5 unde~r: th~
3~ d~ k Y~ X~ p~ h~ sl~.
Th~ f~ r ~l~r,d of ~h~ lnY~n~on ¢~prl~
~ub~t~n~i~lly aph~c~ ocondu~ e psr~cl~s wi~h ~ y ~on~n~u~ p~
The~ ~oDIp~nen~ m~y be b~ ded ~o~th~ by ~ry ~x~rl%
~5 app~op~ia~ q~lanti~ies o ~ne or ~30~0 o~ h ~yp~ o~
p~ th~ u~u~y ~ r .:

2~63~6 7_ ~l~c~oaond~ct~ve p~r~i~le i~ ~urrounded by u8u211y ll~r ~ non~cunductlve p~I~lcl~. Op~ra~le ~lller ~l~nds ~ o ~wh~n th~ r~10 o the ~ 59 p~r~icl~ di~m~t~r of th~ electr~c~ ontu~ti~e 5 p~ e ~va~e p~ic~ ze ~ ~h~ ~n~
~onductlve p~rtlcleo r~n~es from 20-fi0. Ths elQc~ro-~on~uctlve p~l~ticle 9iZe! l~qly ~an~ roT~ 0~5~5~ ml~ron~
iam~t~r and are p~en~ ~n ehe blqlld ~n ~ ~an~e o~
~-55X ~nd p~erably 14 to ~5 percen~ Vby ~olum~
lû wheræin the volume I~tiO o~ ~he non-conductiv~ p~rtl cl@~ ~0 ~h~ ~le~tro~orldl~e~e pArtit:le~ ~n~ f~om 0~25-0.7~. Th~ avera~ di~ter o~ the ~on~¢o~tu~t~
p~rtlcle~ have ~n av~r~ge p~r~lcle ~i~e r~n~ o~
0.005~2 ml~on~ ~nd are pr~s~n~ in ~h~ bl~nd in 15 llmou~ts ~ h ~h~ ~he volt~me ~ o~ th~ norl~conS-du~ p~r~i~les to the ~lec:~o~ondu~ p~r~icl~
er th~T~ 0.25 bUt 1eY~ ~h~n 0.72. A ~erred ra~o ~ abou~ .3 -~4.
Irl prep~ri~ the flllex bl~t o th~ ve 20 ~ he par~icl~s ~y b~ ix~ ~o~her dry ~y ~h~kln~, ~u~ling or ball~miLllln~. In ~om~ ~n~ s, p3:e~er~d to w~ mix ~h@ ~mb~raQ~or ~n l;l.'Sfi'bi=
li2~ad ~qu~oua ~l~r~le~ or a~ ~ r~in we~ d p~e wh~ch C~ e ~ur~her ~ixod tl~c~y 7~i~h ~he ~ind~
~5 ~ n. ~r~ m~ny ~ns~ t ~h~ p~ ul~ nt0 ~e pyropho21c ~nd ~om~ lo~ivo ~ot ~ich ~3~t h~ a wl~;h du~ ~u~n. l~h~g prq~l~m dry blorldi~ in an ~n~t ~tmo~ph~r~.
e~on~u~ e ~a~cl~ p~-~ to omploy p~rt~cl~ ha~ln~ in ~2~o r~n~
~ Z ~o lS tn~cx~n~. Su~h par~ 0 m~y b2 ~ c~d ron ~ e~pç~lly ~ onyl ~on ~uch ~a thal:
~o~m$d fro~ the ~o~troll~d ~ l d~or~pos~t~on of $ron pent~ bor~yl ~ in ~e ~p~c~ ~o prod~c~
~5 ~ph~re~ w~kh a char~ç~r~stl~ ~n~or.~0k$~ st~uc~ur~ d~
to m~nu~;e ~ta~b~n d¢po~$~ ln ~l~ern~n~ l~y~x~s. A

~ 1 1 Ll.l - _JLI 1` 1~ l .L ~ L~ ' I hl'J-~ 1 I rL I ILI ~ :.lt, 1.$~ s~
20:~3~

pa~tlc~ ar~al h~ av~r~ge p~r~:icl~ d~

4~6 ~cr~ns ~ p~ovid~d by ~iene~l An~l~no ~n~ Film Co, ~ ~A~9 Type E. Ad~ltlon41 ma~erialB ~de by thl~
t~hni~qu~ pro~id~d a~ i~on ~ y~ h o~h~

5 t~n~ior~ m~S~a~s. Tn ~ddi~:~on, p~rtic~ ce~
~y ~e ~esl~ed from ~lumixl~m, COpp8~ $1;tlas ~n~
~teel ~n~ oeh~r~ ~lect~d ~:rom par~le~ ~ho~e r~g~-Y ~B 1~B~ ~h~n l ~ l~ o~ t~
oxi~Q ~u~h ~8 oxldes of lroll ~nt chromium a~
lQ corl~mp~ ~ted.
Non~conduc~r~ p~ le~ ~ro ~e~ d ~cho~ with ~reat~r ~hsn 1 x l~ ohm ~ s'G~vity.
R~pr~nl:~eiv~ non~o~duc~ve p~r~ e 01 ln Sho fo~ of mlc~, quar~z, ~ g ~nd o~er ~llea~
15 ~ h ~ e~lc~um ~ilicate, ~lumi~um s~lic~a, ~ireon~um te ~nd ehe l~kev ~l~mlr~a ~n l:h~ ~o~m of al~ni~um a~e~ nl~n dioxide ~nd ~lt~ e~ ~ch ~
b~r~um t;L~nst~, ca~bon~te ~ h ~ e~ luta ea~orlat~, ~ul~t~ ~uçh a6 eal~iuD~ s~ , ox~d~s o~ ~ron ~h 20 ~ f~r~ oxlde and other~ ~u~ ~8 lithiu~ ~luminurn ~lic~t~, ~llicon c~bl~e, ~n~gne~i~am ~il$~t~J ~rco-r~m oxi~@ ant o~h~ gla~e compo~$~or~ ch ~a m~ob~lloon~. O~ co~po. ~tion~ ~nclude plilr~ 5 of ~n~olu~le r~$1n~ ~uch as phenol~c mi~ oorl~ ~nd 25 ~h~ l~k~. ~u~h non-cond~ctlv~ psYti~1~4 ~e p~f~r~d to h~v~ ~ $~bs~n~ially ~ph~ric~l cro3s-~eG~on ~ch Inelude~ ~ph~r~s, ~od~ ~er~ ~nd ~lak~.
The ele~es~m~ne~ r ~ ndl ~y ~o~iLn~d ~ith ~bo~@~d@~crl~ed ~sin ~n~di~nt~ b~ d~
30 ~x~n~ p~til~ Co ~l~d p~dorot 3~in, ~ mix~
~h~ough ~o~ nt depo~ition o~ by ad~ on 'eo polylD~$-i~ing ~e~lns ~u~h ~ ~ho~ u~ n ra~c~lon ~n~t~osl molt~n~ teçhn~qu~ A pr~ r~d ~hod iB ~ Lod out wh~n ~h~ d~d ~nd ~n~ d ~t~
~5 melt~ p~polymers be~ow th~ ng t~mp~tu~4 of ~h~
- ~aé~lyet. ~le~l:r~nlc ~ompanen~ n b~ 4n~b~3cld~d -- ~01636~

~u~h ~lllaa r~s~ ~t a t~mpe~tu2~ ~ove th~ meltlng pO$1~t ~T~d curin~ t~mp~r~ r~v Th~ lend ~n b~ ~p,ol~ to ~iquid r@~ln blnd~rs wh~h ~ h~r ~p~y c~a~ed ~ paint~d on ~h~ su~vce ~ el~c~ron$c 5 compon~n~.
A b~ undes~tan~ing ~ th~ inv~n~ion c~n b~ had by ~f~r~s~ce ~:o Sh4 ~oll~ing not~ m~tln~
ex~P~pl~ whereirl ~11 propo~on~ expr~ed ~r4 by ~el~ ~nle~ oth~ spe~ d~

A 745 ~r~m~ portl~n of lrorl powd~r h~in~
~vesa~e p~r~ dl~me~r 4 4 to 6 rnlc20n~ tGAF~ ~) w~ nuAlly t~y 'blended ~ um~lln~ wi~h ~ 70 15 porl:i~n of ~i~osil~ h~ n ~v~r~ ro~ e~Dr~
D~ 0~ on~ ~h partl~ no ~r~ r ~h~ ron ~EM~ 209 suppll~ ~mical~ Inc ~ ) . Thi~
p~wd~r il~er 11~ c t~en ~h~k~ mix~d wlgh p~wd~r~d re~lncu~ ~n~ s h~ :114 ~r~æ o @pox~di2~
20 ~ ol Tlo~l~c ~ 98~0 suppl1 ~d by ~g~ y~ t ~0 ~r~m~ o~ p~l~o~ ~oriv~d f~o~ ph~ ld~hyd~
no~ol~ ~RPMC~ ppll~d by ~bE~-G~i~y) ~ 10 ~r~
brom~n~ed b~ph~nol 5~P4A supp~le~ b~ C~-~e~gy), S e~m~ ~nt l~ony ~r4 ox1de, 1.1 ~am~ 2~ethyl~m~d-~5 ~le, 2.5 ~r~m~ no~ly~r~l ~t~a~ ~nd ~ ~r~carn~ w~x. ~ p~wde~d ~ r/bind~ le~
the~ ory ~i~e two~r~ll hotJ~ol~ r.$p m~l~ ~e ~ol~ r~ll wa~ cooled ~t 25~-30~C
c~h~ he ho~ r~l wa~ ~t~ ~o a ~q~mp~
30 75-~8~o ~h~'hæat~d roll ~lt~d ~ in lc~
~f~c~Qn~ wæ t~n~ d~ r~ pAr~
~nd, ~ ! hot; roll ~nn~n~ ~ a ~p~ed ~oe~r ~ch~n tho cold ~oll, produe~ heer mlx$n~ ~ the ~n~r~t~
~nt~ p~s~d b~we@n th~ n~p. ~ f~sm~ on 35 pa3~d ~h~ough th~ r~ c~tinuo~ly un~il homog~
~ou~ly ~ixad, ~hen remo~d ~ ~ sh~t wh~h ~8 201~3~
.
wlo-th~ea~tor coola~ ~o ~m ~mp~r~ure~ Th~ ~ld 0h~
m~e~1~1 w~o then p~s~d ~hr.ough ~ d t~o~roll m~11 ~nd ~s~ound to B unl~onn powcl~ h~v~n~ ~ par~cl~ ~lze o ~ 40 ~ Tylor ~v~ ~erles~, ~h~ pow~ d S ~ceri~ th~n to~ u~th~r u~ in ~he m~
ur~ o~ ~n~ n E~ sul~t~d ~le~ na~
~h~el~d el~ct~on~ co~poT~nts.
~ea~
A~o~in~ ~o ~h~ p~vc~du~ outl~rsd ~n ~xampl~ 1, 7~5 gr~m~ on po~d~ S ~rsma ~lk~m 2q5 ~lic~ d 5 ~r~8 ~um~ ca ~C~bo~ H5 h vlng ~n ~v~ e particl~ d~a~er o~ 0.007 ~cson~
~ dry ~lended ~nd ~ix~d w~th ths ~esin bl~2~d of Ex~l~ 1.
~a~
Accord~n~ ~o ~he lp~O~ Ur@ ou~ ed lrl ~x~mpl~ lc~ o~ ~xaa~pl~ 2 ~n d~ r~nt 20 p~por~ion~ fo~d ~n T~le 1 wa~ ~land~d esld t~s~ed ~ he ~ d r~ ompQsl~on~ o~ ~x~pl~
2 ~n~ 3 w~ c~ in~o 4 ln~h dia~e~e2 ~qu~r~ d~
h~vln~ a ~hickn~ vf 1/8 lnch snd e~ d for ~Jolume ~5 r~ tyl ~urf~e re~ lty ~tld di~le~sl~
g~h. rn~e ~ t~e~l p~o~e~ 2~ n Tabl~ 1~

E~ 3 INGREPIENTB PA$~,T~

R~ ~X 1 ~ z ~X 3_ ~pox4d~ d CrQ~ol ~o~ & (ECN'~ O~ 114 ~14 ~h~aol ~Dr~dohy~e NOY~1~S ~j~PMC~O1~A~ 50 50 50 Br~,~d Pol~l BP4A 10 10 10 ,y ~loxi~o 5 5 5 2~ h~ d~i~ol~ 1~1 1.1 1~,1 Monogl~rol oee~ir~i~ e 2~5 2~5 a. 5 ~32~n~Ub~ AX ~ a 2 FILL~R

Xro~, Powte~ ~ 74g 74S 745 Elka~ ~Og) 70 65 60 c~ ab~ 5 1S~CTRICAL PROP~P~TI~8 __ Dl~lact~lc ~tron~th ~B" V/~l ~i~k 1 4~ 27 1~7 3~ 4.
D~k 3 0 17 -~-Yolu~ R~B1~e1~eY toh~
~l~k 1 a .~%~ 4 l .Q~t~15 1~
D1~ 2 1~7~:1015. 5,~Xlpl4 1.9~10~4 ~l~k of~l~o~vle~ ~oh~

6~ 10~ ,xl013 ~gX~ 4 Dl~k ~ 4V57C1OI3 l~4X1O1~ 3-gX1D13 D~k 3 g.7X1nl~ 6.~XIO~

.~/

2~116366 .

~ 4 A copp~r w~r~ wound ~on core ax~ ad~d el~c~rom~qgnet~ n~u¢~ m~ur~n~ 1~ by ~ cm. 15 pl~d ~nto ~ ~cld ~nd ~ncap~ t~d ~l~h 0.33m~D o~
5 compo~i~ion of Exampl~ 1, th~n h~a~ed un~ll ully cur~d. Th~ per~o~nance of ~h~ duc~or i~ 3l~11ar to that h~n~, ~ convent~on~l pr~s~ed ~ ron ~hi~ld .

Claims (11)

1. A filler blend for making electromagnetic shielding resins which comprises, (a) 8-55 percent by volume of electroconductive particles of spherical cross-sectional dimensions ranging from 0.5-50 microns having a resistivity less than 1 x 102 ohms, and (b) electrically non-conductive particles of spherical cross-sectional dimensions ranging from 0,005-2 microns having a resistivity greater than 1 x 108 ohms.

2. A filler blend of claim 1, which comprises 14-55 percent by volume of electroconductive particles wherein the volume ratio of said non-conductive particles to said electroconductive particles ranges from 0.25-0.72.

3. A blend of claim 1 or 2, wherein said electroconductive particles are selected from the group consisting of iron, iron alloys, copper, aluminum, silver and electromagnetic oxides of iron and chromium.

4. A blend of any one of the preceding claims, wherein said electrically non-conductive particles are selected from the group consisting of silica, mica, quartz, glass, calcium silicate, aluminum silicate, zirconium silicate, alumina, titanium dioxide, barium titanate, calcium carbonate, calcium sulfate, ferric oxide, lithium aluminum sulfate, magnesium silicate, zirconium oxide and insoluble resin beads.

5. A blend of claim 4, wherein said electroconductive particles are carbonyl iron and said non-conductive particles are silica.

6. A blend of claim 5, wherein said particles of iron ranges from 2 to 15 microns and said silica ranges from 0.005-1 microns in cross-section.

7. A blend of claim 6, wherein the volume ratio of silica to carbonyl iron ranges from 0.3-0.4.

8. A molding composition comprising a uniform mixture DET: 1924A-56073 of a filler blend of any one of the preceding claims with an electrically non-conductive binder resin selected from the group consisting of thermoplastic and thermosetting polymers having a volume resistivity of at least 1 x 1010 ohms-centimeters.

9. A composition of claim 8, wherein the volume of said filler ins aid resin is 30-80 percent by weight.

10. A composition of claim 8 or 9, wherein said binder resin is selected from the group consisting of polyepoxides, polyamides, polyimides, polyesters, polyethersulfone, polyetherether ketone, and blends thereof.

11. An electromagnetic indictor having an effective amount of the protective electronic shielding resin coating of a cured molding composition of any one of claims 8-10.