CA1326591C - Composites of stretch broken aligned fibres of carbon and glass reinforced resin - Google Patents

Abstract

TITLE
Composites of Stretch Broken Aligned Fibers of Carbon and Glass Reinforced Resin ABSTRACT OF THE DISCLOSURE
A coating of a viscous lubricant applied prior to stretch-breaking permits forming slivers of stretch-broken carbon fibers. When an anti-static ingredient is added to the viscous lubricant cohesive slivers of stretch-broken glass fibers can be formed.
Composites of matrix resin reinforced with these slivers exhibit high strength, tensile stiffness, and good formability.

Description

1 326591 ~ ~
TITLE :~
Composites of Stretch Broken Aligned ~ibers ,,~ o~ Carbo~ and Gla~ Reinfor~ed Re~n :~-~; ~ackqround of the Invention ~hi~ invention relate~ to a proces~ ~or ~tretch , breaking carbon and glass filament~ and u~ing the;, stretch broken ~liver~ therefrom to Eorm a co~posite of `, eith~r ~ matrix reinforced with carbon fiber~ or a -j matrix reinforced with glass fiber~.
.,~ 10 Composite ~heet~ of either conti~uous filament .~ carbon ~lber reinforced resin or continuou~ fila~ent glass fiber reinforc~d re~in have been ~ade. One technique i~ to prepare a warp of ~ilament6 as by i wlnding on a ~rame, impregnating them wlth r~in~ ~nd :, 15 hot pres6~ng to form a thin flat ~heet which is cut from the frame. Several such sheets are then cros~ lapped and ~gain hot pres~ed to form the fin~l reinforced co~po~itc product. Such product~ h~ve high ~trength and tif~nes~.
2~ Problems occur when ~ttempts are made to produce deep drawn three dimen~ional article~ by hot pre&6ing continuou~ carbon ~r glass fil~ment containinq . re~in ~heets. ~he article~ in ~any ~nstanc~s ~xhibit uneven areas and wrinkle~. ~he u~e of 6taple carbon or :~ 25 gla6~ f~bers ~ reinforce~ent sub~tant~ally ovorcomes ~;~ the ~bove-stated proble~s but ~t a g~t 6ncrifice to 8trength 2nd stiffne s.
In a 6imilar s~tuation involving P-~ramld fiber6, olution to the aforement~oned problem was the ~ 30 u6e o~ certain stretch broken P-aramld fibers a~ -.l disclo~ed by Fish and ~uterb~ch in U~S. Pat~nt No.
~, 4,5S2,805. However, becau~e carbon a~nd gla~;s i:1aments ~xhibit little or no cohe6ive capability when proce~sed according to known 6tretch-break~ng proce~e~, ~liver~
. ~ 35 of carbon or gla~s ibers have not been able to be formed by the~e known proce~se~.

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. 2 ~: ~ The present invention permits forming cohe6ive livers of ~tretch broken,fila~ent~ of carbon and glass or u~e in forming a composite carbon or gla~ f~ber reinforced resin u~eful for deep dr~wing purpos~g with ~, 5 little 6~crifice of ~trength and ~tif~ne6~.
Summary of the Invention A cohesive sliver o~ ~treteh broken gla6~ or carbon flber~ having a high d~gree of axial alignment ~nd a co~ting of ~ finish compri~ing a viscou~ lubric~nt ;, ~ and an anti-~ta~ic ingredient. Compo~ite6 of ~ matrix , re~in reinforc~d with 6ueh ~liver~ and 6h~p~d structure~
~, for~ed therefrom are al60 encompa~ed.
Brief ~escriPtion of the Drawin~
- Fig. 1 i~ a schematic illu tration of ~
preferred e~bodiment apparatus for u6e with 3 eontinuous proce~ ~n the practice of the pre6ent ~nvention.
Fig. 2 is a schematic illu~tratlon of apparatus : ~or ~pplying ~ini~h to a carbon or glas~ ent yarn.
'. rig. 3 is ~ hematic illu~tration o~ apparatus ~ 2a for 6tretch-breaking a cohesiv~ carbon or 9~ y~rn.
:!, Detailed DescriPtion of the ~referred Embodiment ;~s Referring to Fig. 1, the pre~erred embodim~nt j gener~lly ~n~ludes a ereel 10 for yarn ~upply pacXage~
12, a plurality of yarn tçnsioning bar~ gen~rally designated 14, a finlgh applicator 16 compr$~ed o~ a -l rotatable f~nish roll 18 emer~ed in a pan 20 illed with '~ ~ liquid ini~h 22 a pair of groov~d roller guides 24,26 are l w ated between the flni~h applicator 16 ~nd ~ Turbs7 ;`l S~pler 2B (manufactured by the Turbo Machine ~o., L~n~ale, Pa.). The Turbo-5tapler i~clude~ a p~ir o~
driven nip roll6 30,32 which ~irmly grip th¢ tow band 34 'I that ha~ been eonsolidat2d fro~ the individual y~rns in ~;! guide 29. The nip roll6 30,32 feed tow b~nd 34 ~ a con~tant rate to a pair of front roll~ 36,~8 wh~ch also grip the tow band 34 and withdraw lt from br~ak~r bar~
39 and feed ~t ~s a 61iver to a condens~ng guldQ 40 rom ~ ~ 3 l 326591 which the 61iver i~ fed to a windup (no~ 6hown) for packaging.
~ ~ ~n operation, gla~s or c~rbon yarn 13 rom -. individual packages 12 is fed from cr~el 10 over finish roll 18 where it is coated with fini~h 22. ~he yarn~
are c~n~olidated in guide 29, ten~ioned between rolls 39,32 ~nd front roll6 36,38, then randomly broken by ~harply d~flecting them laterally by the bre~ker b~r~
39. The coating of ~ini6h on the yarn in the ~liver i~
~uff~cient to enable the ~liver to be~ pulled through guide 40 to the windup without di~a~l,oc~tion of the ; ~iber~ ~n the ~liver.
r' While the continuous proce6~ illustrated in :~; Fig. 1 16 preferred, the application of inish o ~ 15 continuou~ ~ilament ca~bon or glas~ iber~ ~nd the 1- ~t~etch-breaking of ~he coated ~ ment~ can be carried out in two ~teps; i.e., separate finish Applica~ion ~nd ;~ ~tretch-bre~king proce~e~, a~cording to Flgs. 2 ~nd 3 . and DS de~cribçd ~ub~equently in Ex~mple 1. More : ~ particularly, ln Fig. 2, glass or carbon yarn 13 from package 12 i~ fed ov2r yarn tensioning bar~ 14' over ~: Pini h roll 18 where it is coated w~kh fini~h 22 and ~ wound onto a bobbin 12' and allswed to dry. The yarn -~( from bobbin~ 12' ~ then ~tretch-broken ~y br~aker b~r6 39 (Fig. 3) in the turbo-~tapler as d~gcribed above in , connec~ion with ~ig. l.
:, The finish u6ed ln thi~ invention i~ ~ material that causefi an interfil~ment viscou~ drag ~ufficiently J, high to permit the handling requlred to ~ake ~
1 30 compo~it~, such as winding and unwind~ng from ~ package.
More particularly, the f in~ ~h used for the carbon fiber ~pplic~tion i~ a ~ixture of ~ one par~ o~ a ~uitable anti6tat and two part6 of ~ non-tacky vi~cou6 lubric~nt of ~ consistency to ~mpart ~o the chopped ~l~v~r ~dequate cohe~ivene6s ~minimum of .01 gram~ p~r denier) without tack~ne6s or without compromislng the l 3 .~, ii ~ . , `:

fib~r-matrix ~dhe6ion in the final compo~ite. The ant~tat p~rt$on of the mixture could be reduced or even liminated $f the reinforcing fibet i~ el~ctrically ~;: conductive (e.g., c~rbon fiber~).
A ~uitable vi~ous lubricant i6 polyethylene glycol (400 ~ol. wt) ~onolaurate and a l~urlc ~m:Lde ; while ~ 6uitable anti6tat i~ mixed ~ono And di-pho~phate e~ter6 of C8-C12 fatty aleohol~ neu~raliz~d with diethanol amine.
PreEerably, the percent fini~h on ~ber i6 in the r~nge of from about 0.3% to ~bout 0.5%.
~;i Formable planar and shaped non-pl~n~r omposite~ are conte~pl2ted by the pre~ent $nvention.
. For the for~able composite~, that i~, tho6e compo~lte~
that c~n be formed into 6haped non-planar thr~e-dimen~ional structure~ at ele~ated t~mperatures (where nece6~ary), matrix resin~ of the thermopl~stic variety or of the not fully cured thermofiet type ~ay be employed. }n the latter case the thermo~ettable-resin ~:~ 20 ~ cured after the composite ha~ been ~hap~d~ Suit~ble thermopla6t$c resins include polyesters (including copolye~ter~)~ e.g., polyethylene terephth~late, Kodar .~ PETG copolyester 6763 (East~an ~odak~; polyamide&, e.g., nylon 6,6; polyolefin~, e.~.~ polypropylen~; al~o ~ncluded are the high temper~ture resin~ su~h ~æ an ~¦ ~morphou~ polyamide copolymer ba~ed upon - bi~para-aminocyclohexy~ thane, a ~eml-cry~talline ~i polyamide homopolymer also ba~ed on bi (para-aminocyclohexyl) methane, and polyetheretherketone. Thermo6etting r~ins tha~ re i u~eful include phenoli~ re~in , epoxy re~in~ ~nd vinyl : ~ e6ter r~sins.
The r~tlo of reinforcement to ~atrix c~n v~ry, but preferably i6 ~etween 40% to 7S~ ~y volume. ~he ~ 35 ~verage fiber ~engths ~160 may v~ry but prefer~bly r~nge : ~ q :

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` 5 ~ 1 3265ql r from about }/2 to about 6 inch@s in length with a random ~ overlap distribution. A~,out 85 percent of ths fibers -: are allgned within ~10 degrees, preferably ~5 degree~ of the axial direction.
The compo6ite ~ay be ~ade by a var~@ty of procedures. Thus, a ~trçtch broken 61~ver ~y b~ wound on ~ frame covered w~th a film of thermoplastic resin to form a w~rp. The warp of ~tretch-broken sliv~r, however, can be made by ~ny technique ~nown to those skilled in the art, e~g., by creeling or bea~ing. A
preform i5 obtained when another ~lm cf thermspla~tic resin i~ placed over the warp ~o for~ a 6andwich which ; ~ heated in a v~cuum bag and then re~ov~d ~rom th~
~rame. Sever~l of such preform6 may be ~tacked while ofset to provide ~ulti-direc~ionality ~nd then the 6t~ck ~ay be heated under pressure to form a compo~ite ~tructure.
~:. Other techniques for applying ~atrix polymer ;~ include ~prinkling of powdered resin on the ~liver warp ~, 20 followed by heating to melt the r~in, flowing liquid re~in over the 61iver warp, in~er~ingl~n~ thermopla~tic fiber with the ~liver warp and then heating ~o m~lt the ~ thermopl~stic fiber thereby fDrming the ~atrix re~in, -~ calendering the warp between layers of ~atr~x fil~, etc.
¦ 25 Te~t Procedures .~ Compo6ite Ten~iie -~ ^ The co~po6ite tensile t~t~ ~ollowed ~he `~ gener~l procedure de~cribed in AS~M Test D 3039-76 :~ enti~led ~Standard Te6t Method for Tensil2 Propertie of Fiber--Re~in Composite~> n Short Beam Shear The short beam she~r test~ ~ollowed the general ; procedure de6cribed in ASTM Method D 2~3qq-76 entitled, "Standard Te~t Method for ~pparent Int;erl~minar Shear ~trength o~ Parallel Fiber Co~po~ite~ by Shor~ Beam ;i : .
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~: ' 1 3265ql Method" with the followin~ except1on, the lo~ding no~e w~s 1/16 ~nch radius in6tead of 1/8 irr~h.
Sliver Cohesion ~ he yarn 'co be te~t~d ~or 61iver cohe~ n wa~
5 placed in the clarap~ of an In6tron*,~en~ile t~tl3ng ~chine ~et to ~ gauge length of 17 lnche~, a cro~head ~; speed of 10 ~nche~ per ~ninute and ~ chart spe~d o~ 12 ~nche~ per ~n~nute. ~he cros~head w,~s ~tarted to apply ten~ion to ~he sample and the fflaxi~um force ~n grams 10 ~ndic~ted on the chart wa~ recorded and divided by the 61iver den~ er to ~ive the 61iver cohe6ion.
Fini~h on Yarn Finish ~n yarn ~ deter~ined in a method . wherein we~ yhed specimen~ ~re extr~cted gravimetrically 15 with pre~;cribed 6olvent~) at room ~e~Dp~rature, the olvent contain~ng dis~olved fini~h and any sther :. ~aterial~ which may w~æh of f ~he speci~en~, i8 ~: trDn~ferred 'co ~ preweighed cont~iner ~nd eY~porated~
:~ i The extr~ct~ble re~idue ~ weigh~d. ~ercen~age 20 extr~c~able6 b~zed on extr~c~able-free ~p~cl~n weight i~ calcul~ted. AerothaneÇD ~171,1-trichlors~l:hane~
u~ed a~ the ~olvent for all fin~h m~terlal6 ~xcept . I glycerine ~nd ~e'chanol 1~ u~e~ aC the ol~n~ ~or tha~
materlal.
27j Hi~h T~perature Tensile I~rawing The 6a~pl~ ~o be ~e6ted wa~ placed ~n the cla~ap~ of ~n ~nstron 'censile testing ~achine ~t to a p~rti~ular gauge length and a crosshead sp~ed dependin~
on the ~a~ple. ~ thermocouple was attach~d the zur~cs 30 o the 6ample midway between the clamp~ and an B irlch long eleotrically heated cylindricDl oven was pl~ced around the sample leaving ~ one in~h 6pZlCe between the bottom of the ~ven and the lower c}aulp, Th~ open ~nd~
o~ the olten were plugg~d with in~ulaltion ~ eri~l to 35 prevent convective he~t 106~; and heatirJg of the slamps.
* denotes trade mark :

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1 3265ql -~- 7 The oven wa~ turned on and ~he ~a~ple heated to reduce its vi~c08ity to permit ~r~wing (temperature determined by the viscosity~ time, temperature d~ta of he ~atrix material. Sampl2~ ~ade with ~hermosetting matrix re6ins ~ust be te~ted ln their uncured state.). ~he ~mple was :~ held at thls temperature for 15 ~inute~ to i~ ure thermal Rguilibr$um. The cro~head wa~ then ~tarted ~nd allowed to run until the hsated section of the sample was drawn 50%. The oven wa6 removed and the ~ample in~pected to determine whether it had broken.
Fiber Orientat$on A photomicrograph of ~he sur~ce o~ the composite ~enlarged 240X~ wa~ prepared. The angle between e~ch fiber ~Xi8 ~nd the ~x~al direction of the : 15 compo6ite was mea~ured with a protr~ctor on the ~ photomicrograph ~nd tabula~ed. ~he percentage of fibers `~ with an ~ngle within + 5 degrees of the ax~l direction ~! was reported.
Example 1 Four bobbins of 2000 denier continuou~
.~ filament carbon fiber (3K AS-i fro~ Nereul~ Inc.) were prepared for stretch-breakin~ by applying a fini~h ~:
compo~ed of two part~ of a lubricant ~poly~thyl~ne -~f glycol monolaurate and a lauric amide~ and one part Df an ~nti~tat (mixed ~ono ~nd d~pho~phate ~terE o~ C8-C12 l fatty alcohol~ n~utralized w~th dieth~nol ~in~). The ~ int~h wa~ applied by running the continuou8 fil~men~
:?~! carbon fiber, one bobbin at a ti~e, at 75 yard~/minute over a finish roll which was wet with a 4% aqueou~
~mul~ion of the lubri~ant-dnti~tat mixture ~Fig 2~. The ~:
four bobbin~ were ~llowed to 6tand overnlght to :1 evaporate ~he water. ~ini~h level ~f~er drying wa~
0.33%.
The four bobbin~ of carbon fiber w~re ~i 35 stretch-broken on a ~urbo-etapler ~Turbo Mach~ne Co., ., ;, 1 3265q 1 Lan&dale, P~) a~ ~hown in Fig 3. The 6urP~ce 6peed of the rolls t30,32) wa~ 35,4 yards/~inute and the ~urf~c~
:: 6peed of the front rolls ~36,38) was .llO y~rd~/minute.
The tip ~peed o the breaker b~r6 (39~ was 71 : 5 yard6/minute. The resulting sliver w~s 2422 ~eniQr and h~d ~ cohe~ion value of O.lB gr~ms/denier which w~
~ 6uffic~ent to allow winding w~thout twist on a ; cylindri~al paper tube u~ing a ~ee60n~*type 959 winder.
~:: The average f~ber length o~ fif~cy ~easure~nts of thi~
sliver was 3.2 inche~ (~hortest 0.7 Inch, longest 5.6 , inches ) .
A warp was prep~red ~ro~ thi~ sliver by winding Z. it rom the paper ~ube, 25 ends ko the inch on ~ 16 inch ~quare metal pl~te. A 2.0 ~il thick film o~
ther~optastic refiin ~Dn amorphou~ polyamide copolymer ba~ed on bi6(p~ra-~minocyclohexyl) raeth~ne) wa~ pl~ced .j on the ~ra~e b~fore win~ing the sliver and another wa~ ~ :
~ ~dded a~ter winding was complete. I~h~ entire ~arldwich ,., w~s vacuum bagged at 2B0C for 15 minute~ after ~,/hich time it W~5 cut from the plate. This product, cnlled a pr~form wa~ now a well-impregn~ted, relat~vely 6tiff matrix/~tretch-broken 61ivsr sandwiGh~ ~n whioh ~ll the .~ gl~ver~ were ~ ned in one direction.
Twel~o o~ the~e prefor~s w~re ~tacked on top of one another with all the flbers in the i;~lll2 direc~ n-h~ s 6tack was heated in ~ ~old ~t 305C ~t 500 pound~
~ per ~quare inch for 35 minutes to malce ~
~i well-con601idated pla~e 93 ~lls thiçk ~nd flber volume fraction of 55%. 5hor~ beam 6he~r ~es~ conducted on 1 30 O.S inch wide 6trip~ cut from hi6 pl~te gave ~ v~lue of 13,700 pound~ per 6quare inch. ~t wa~ concluded that the presence of the finish did not ~dve~6ely affect Sh~
~dhes~on of the f~ber to ths matrix p~lymer.
l A 6econd plzte wa~ made f ro~ t~n of thes~
35 preformfi by ~t~cking th~ so th~t the dlr2ctlon of the ; * denote~ trade mark : .1 .~1 . ~ .
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1 3265q 1 6tretch-broken fibers were off~et by 45 degree~ ~n a clockwi~e direction in s~ccessive layers. The bottom plane of the ~ifth layer wa~ oon~idered ~ reflecting plane and ~he next ~iV2 layer~ were ~tacked ~o ~hat the w~rp directions of the stretch-broken ~liver wers mirror image~ of the top five layers with re~pect to that plane. ~hifi 6andwich was molded a~ above to ~ake a well consolidated plate with a fiber volumle ~ract~on of 55~.
This plate wa~ heated to 322C ~nd molded lnto ~
hemisphere with a radiu~ of 3 inche~. The plate conformed very well to the shape of the ~old hnd it was concluded that the product was deep draw~ble without wr~nkle6.
Example 2 A ~liver of 6tretch-broken glas6 f~ber was prepared by the method in ~xample 1 ~xceyt that 6700 denier continuous filament gl~ fiber wa~ u6ed (T-30 ~
P353B from Owen~-Corning ~iberglas6) ~nd the f~nish was ~:
applied by spraying a 10% ~queous emulsion on the fiber. ~ :
The emul6ion was pumped to the ~pray nozzle at 5 cc. per minut~ and the air pressure u6ed was ~ psi. ~he yarn was pullçd past th~ ~pray head ~t 55 yards per minute by :
a pair o$ nip rolls and wound on a cylindrical paper tube3 After drying, the fini6h level wa6 0.35%~
Str~tch-broken ~liver WD~ prspared from two ~ini~h treated continuou6 filament bobbins and h~d a cohe6ion of 0.09 grams per denier which wa~ adequa~ for winding as in Example 1. Further, the fini~h controlled 6t2tiC
generation in the stretch-breaking proce~s to An acceptllble level. The ~verage fiber length of ~ifty measur~ments o~ ~hi6 61iver wa~ ~.4 inche~ (~horte6t 1.0 inch, longest 10.2 inches).
A unidirectional plate wa~ made rom thil;
sliver ~nd PETG film ~odar~ PETG copolye6te~ 6763, ~5 Ea6tm~n ~odak) by the method of ~xample 1 exe~pt that the 61iver ~pacing was 26 ends per inch, the f~lm .

thickne~s wa6 3.0 mil6 and B layer~ o~ preform were u~ed to 55% fiber volume fraction. Short beam ~hear test~ on 0.5 inch wide ~trips cut from thi~ plate g~v~ ~ result of 5,400 pound~ per ~qu~re inch. It w~ conclud~d that the pre~ence of the flni~h did not ~ff~ct th~ adhesion of the flber to the ~atrix polymer.
xamQle 3 A ~ample of carbon fiber ~liver wa~ prepared using the ~tretch-br~aking process of Example 1 except that fin~sh was no~ pre-appli~d ~o the continuou~ fiber and two bobbins were u~ed ~n~tead o~ four. The two end~
of carbon fib2r were contacted by ~ ~lt pad ~turated with glycerine which was placed between the t~n~on guide and th¢ infeed roll. Glyc~rine level on the ~liver wa 0.5%. The aver~ge fiber length of flfty measurement~ of thi~ sliver wa8 3.2 inches (~horte~t 0.6 inch, longe t 7.9 inch). Cohe~ion w~ ~easur~d as i~
function of ~ime v~. the ~liver from ~xa~p}e 1 with ~he follow~ng result~.
Cohe~ion, qrams per denier Days ~lycerine Example 1 l .SB .15 9 .79 .~q 16 .02 ~5 22 .~2 .25 .Q2 .21 xample 4 Glycerine treated 81~ver Prom ~:xample 3 WAS
~ade ~nto a warp, preforms and a unidir~ctional plate by the nethod of Example 1. Th~ ~nd count w~ 12 per inch, the film wa~ 3.0 mil thick ~ETG (~odar P~TG copolye~ter 6763 from ~astman Roda~ ~nd 6 preform6 were ~t~cked to ~ake the pl~te which wa~ 40% iber volu~e fraction. Th~
plate wa6 cut into 0.5 inch 6trip6, provided with aluminum tab~ and subjected to ten~ t26t6 at B inch guage length with the following re~ult~:

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Ten~ile strength, p~i. 127,400 Modulus, psl. 11,600,000 It wa~ eonoluded that the product had v2ry high strength and modulu6. The unifor~ity of orientation of the iber6 on the surface of thi~ plate were ~ea~ur~d from a photomicrogr~ph ~nd it w~ found that 85% of thQ fiber~
were within ~ 5 degrees o the axial directlon.
Example 5 Continuous ~ r~ent 2000 denier c~rbon fiber 1~ w~ made ~nto a warp, preforms and ~ unidlrectional pl~te. ~he end count was 12 per inch, the f~lr~ w~ 3.0 ~il thick P~G ~Rodar PETB copolyester 6763 from Ea~t~an Rodak) and 16 prefor~s were 6t~cked to make the plate w~ich was 4~% fiber volume fractio~. ~he pl~te was cut ~nto 0.5 inch ~trip~, prov~ded with alumlnu~ :
t~bs ~nd ~ubjected to ten~ile te~ts ~t 8 lnch guage length with the followlng re~ult~:
Ten~ile strength, p~i. 139,800 Modulus, p~i. 11,600,000 It wa~ concluded that the product of Ex~ple 4 ~xhibited the ~trength ~nd stifne~ expected of cont~nuous filament carbon fiber. ~he product o~ Exa~ple 4, although nade of ~tretch~broken di6cont~nuous ~t~ple fiber, c~me within 90% of the ~trength and ~t~ iE nes~ oP
25 the continuou~ fila~ent prsduct. Th~6 ~xcol~nt per~or~ance is believed due to the hlgh deyree o~ order of the stretch-broken fiber~.
Exampl e 6 ~tretch broken gla~ ~liver was prepared by the 3~ ~ethod o~ ~x~mple 2 except that f~ni6h w~ ~ot pre-~ppli~d to the contis~uous ~iber. Inzt~d, the ~iber Ibeing 6upplied to the Turbo-stapler wa~ spr~yed periodi~ally with Jif-Job*antlst~t~c ~pray ~Schafco, Lancaste~, PA). ThQ roll and bre2ker b~r ~p~d6 were one-h~lf the value6 in ~xample 2. ~h~ av~rag~ ~ber * denotes trade mark length of fifty measurements of this 61iver wa~ 3.1 inches (6horte~t 1.0 inch, lonqest 5.8 inch). This 81iver was made into a warp, pr~forms and a unidirectional plate by the method of ~x~mple 1. The end count was 21 per inch, the film wa~ 3.0 mil thick PETG (~odar PETG copolyester 6763 fro~ EA~tman Rodak) ~nd 5 preforms were 6tacked to make the pl~te ~hich was 40% fiber volum~ fraction. The plate was ~ut lnto 0.5 inch strip~, provided with aluminum tab~ and ~ub~eeted to tensile tests at 8 inch guage length with the ollowing result~:
Tensile ~trength, psi. 67,200 Modulu~, psi. 4,950,000 It ws~ concluded that the produc~ had very high 6trength ~nd ~odulu6.
Example 7 Co~tinuous fil~ment 6700 denier gla~s fiber wa6 ~de ~nto a warp, preforms and a unidirectional plate.
The ~nd count wa~ 13 per inch, the fil~ wa~ 3.0 ~
thick PETG ~Kodar~ PETG copolye~ter 6763 ~rom Eastman Rodak~ ~nd 5 preforms were stacked to ~ake the plate which wa~ 40% fiber volume fraction. ~he pla'ce waE cut into 0.5 inch strips, provided with aluminum t~b~ and 8ubject~d to tensile te~t~ ~t B inch gu3ge l~ng~h wi~h the following results:
T~n~ile ~trength, psi. 6~,900 Modulus, psi. 5,460,900 It wa~ concluded that the product of Example 6 exhibited the ~trength and ~tiffnes~ expected o~ continuou~
fil~ment glas fiber. The product of Exa~pl~ 6, ~lthough ~ade of discontinuou~ ~taple fiber, ca~e withi~
90% of the ~trength and stiffne~ of the con~inuou~
~llament product.

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13 1 3265~1 Example ~
A preform of stretch broken carbon fiber 61iver ~n an epoxy resin ~ercule~ 3501-6) wa6 made by the following procedure:
1) The frozen resin wa~ thaw~d at r~om temperature, then heated to 180DF for 15 ~inu~es.
2) ~ film of resin was c~s~ onto relc~6e paper then chilled to 40F to ~top the polymerlzation reaction and the exposed 6urf~ce was covered ~ith polyester ~ilm for prot~ction. ~-3) The paper-re~in-film ~a~dwich wa~ wound on a 7-foot diameter drum and the polyester film removed.
4) 2300 denier yraphite ~liver ~aa2 by the process of ~xample 1 w~s wound on the exposed resin at 9 ends per inch for a total width of 10.5 inches. The average ~iber length of fifty ~easurement~ of thi~
gliver was 3.2 inches ~hortest ~.7 inch, longest 5.6 inche6).
5) ~he polyester film was removed from a ~econd paper-resin-film sandwich and wound over the ~raphite layer on the drum to ~ake a pape~-resin-graph;te-resin-paper sandwich.
6) The ~andwich w~s unwound from ~he drum and vacuum b~gged flat ~t 140F f~r 10 ~inute~ to force the resin into ~he graphite l~yer, then ~rozen for later use. The thickne~s of the resin-gr~phlto part of this sandwich wa~ 7 ~ils.
A unidirectional composite stri2 ~de by ~tacking together ten Iayers of 3/4-inch wide ~nd 14-inch long ~trip~ ~fiber direction parallel to the 14-inch dimension) of the gr~phi~e-r~sin preform was vacuum bagged ~or two minutes. One inch on either end of the ~trip was partially cured by heating it t~ 120DC
~or two hours while keeping the middle 12 lnches of the strip cold with dry ice. At a guage length o~ 11 inche ~ 326591 and ~ cros~head ~peed of 5 inche6 per ~inute, a hiyh temperature ten~ile drawiny test was conducted ~t 124C
on the 14 lnch long by 0 75 inch wlde 6trip wh$ch showed : the composite could be drawn 50% without breaking, 5 predict$ng a high degree of formability.
A composite plate ~as made from 10 layer~ of the ~andwich from ~tep 6 above by removing the release : - :
p~per, cutting the graphite-rç~in preform ~nto 6heet~
~nd 6tacking them so tha~ the direction of ~he str~tch-broken fiber~ were offset by 4S desree6 in clockwise direction in succes6ive layer6. The bottom plane of the fifth layer was con~idered a r@flecting pl~ne and the next five layers were ~tacked ~o th~t the warp directions of the stretch-broken ~liver were ~irror image6 o~ the top five layer~ with re~pect to th~t plane. Thi~ ~andwich was vacuum-b~ged at a~bient temperature for 2 minutes to ~tick the l~y~r~ together.
Thi6 plate wns molded into ~ bemi6phere wlth ~ radiu~ o~
3 ~nche~ and cured in the mold at 175C for 2 hour6.
The pl~te oonformed very well to the 6hape of the mold and it was concluded that the produ~t was.for~able.
Example 9 Four bobbins of 2000 denier continuou~ filament carbon ~$ber (3~ AS-4~from Hercules Inc.3 were 6tretch-broken o~ a Turbo-~t~pl~r (Turbo ~chine Co., Lan6dale, PA) ~et up a~ ~hown in Fig 1. A 10% aqueous ~olution of the f$nifih descr~bed in Ex~mple 1 wa~
applied with a wetted roll. The surf~c~ ~peed of the intermediate rolls wa~ 17.7 yard6/~inu~e ~nd the 6urface 3~ ~peed of the front roll6 was 55 yard6/~inu~e. ~he tip ~peed of the breaker bars was 35~5 yard~/minu~2. ~he resulting ~liver was 2250 denier. The average fiber length of fifty ~ea~urement6 of thi6 61iver was 3.3 inches ~6horte6t O.B inch, longe~t 5.5 ~nche~3.

1 3265~1 A warp was prepared from this ~liver by winding it, 27 ends to the inch qn a lB inch square met~l plate.
A 3.0 mil thick film of thermoplastlc re~in (PETG
copolyester) was placed on the frame bef~re winding the sliver and ~nother was added after winding was complete. The ~ntire ~andwich was vacuu~ b~gged at 220C for 15 minutes ~fter which time it W~6 cut from the fr~me. Thi~ product, called a preform was now a well-impregnated, rel~t~vely stiff matrix/stretch-broken 61iver 6andwich, in which ~11 the ~liYIer~ were aligned in one direction.
Seven of these preforms were stacked on top of one another with all the f~ber~ in the same direc'cion.
This stack w~ heated in a ~old ~t 200C at 400 pounds per square in~h for 30 ~inute~ to ~ak~ 3 well-consolidated plate B2 mils thick and ~iber vol~me fraction of 50%. High temper~ture t2n~ile drawing te~tC
~t a guage length of 10 inches and cros~head 6peed ~f 10 inches per minute conducted at 262C o~ 12 inch long by 2~ 0.75 inch wide strips cut frsm this plate with the fiber direction parallel to the 12 inch dimen~ion showed the compo6ite could be drawn 50% with~ut br~aking, predicting a high degree of formabili~y.
~xample 10 Two bobbins of 1;700 denier continuou~ filament glas~ fiber (T-30 P353~ from Owen~-Cornin~ Fiberglas~) were 6tretch-broken on a Turbo-stapler ~Turbo Machine Co., Lansdale, PA) set up A5 ~hown in ~ig 1. ~ 10%
aqueous ~olution of the fini6h described in ~xample 1 w~s applied with a wetted roll. The ~urface ~peed of the inter~ediate roll6 was 17.7 yards/minute and the surface Gpeed of the front rolls wa6 55 yards/minute.
The tip ~peed of the breaker bar6 was 35.5 yards/minut2.
The resulting 61iver was 4100 denier. Th~ ~Yerage fiber length o fifty measurement~ o~ thi~ ~liv~r was 3.4 inche~ (shortest 0.9 inch, longe6t 8.7 inches).

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A warp was prepared from this 61iver by winding it, 22 ends to the inch pn ~ 1~ inch 6quare metal plate. :
A 3.0 mil thic~ film of thermopl~stic resin (PE~G
copolyester) was pldced on the frame before wlnding the ~liver and another was added after winding wa~ complete.
The ent~re ~andwich w~s vacuum bagged ~t 220~c ~or 15 ~ :
~inu~e6 after which ti~e i~ was cut from t~e frame.
Thi~ product, called ~ preform wa6 nQW a well-impregnated, relatively ~tiff matrix/stretch-broken sliver ~andwich, in which all the ~liv~sr~ were aligned in one dire~tion.
Seven of these preforms were stacked on top of one ~nother with all the fibers in the same direction.
Thi~ ~ta~k was heated in ~ mold ~ 2C0C ~t 400 pounds per square inch for 30 ~inutes to make a w~ consolidated plate 82 mil~ thick ~nd flber volume fr~ction o~ 50%. ~igh temperature tensile drawing te~t~
at ~ guage length of 10 inches and cros6head ~peed of 10 inche per minute conducted at 262C on 12 inch long by 2~ 0.75 inch wide strips cut from thi~ plate with the ~iber ~irection parallsl to the 12 inch dimen~ion showed the co~posite ~ould be dr~wn 50% without breaking, predicting a high degree of ~ormability.
Example 11 Sliver from Example 10 was re-br~ken to reduce the ~iber length by passing it through two set~ of ela~tomer ~oated nip roll~ with a ~eparation of 2.50 inche6 between the nips. The ~urface 6peed of the 6econd 6et of rolls was 10 yard~ per ~inute and the 3~ 6urf~ce 6peed of the fir~t ~et of rolls w~ 7.1 y~rd~
per ~inute giving a draft of 1.4. Denier of this re-broken ~liver was 5371 ~nd the ~verage f~ber length o~ fiity ~ea~urement~ of this sliver wat 1.57 inche~
(6horte~t 0.5 inch, longe6t 3.6 ~nche~).

A 'w~rp' wa6 prepared from this liver by winding it , 17 ends to the lnch on a lB inch 6quare metal plate. A 3.0 mil $hiclc fil~ of th~r~oplastic resin ~PET~ copolyester) was placed on the fr~me before winding the ~liver ~nd ~nother w~6 added ~fter winding was co~plete. The entire sandwich wa~ vacuum bagged at 220C ~or 15 minutes after which ti~e it was cut }rom the fr~me. This product, called a prefor~ was now a well-impregnated, rel~ively stiff ~atrix/stretch-broken ~liver 6andwich, In which all the 611ver~ w~re aligned in one direction.
Seven of these preforms were ~tacked on top of one another with ~11 the fiber6 in the ~me direction;
~hls ~tack was heated in a ~old ~t 200~C ~t 400 pounds per ~guare inch for 30 minute~ to make a well-consolidated pl~te ~0 mils thick and fiber volume ~raction of 50%. High temperature ten6ile drawing te~ts at ~ guage lenqth of 10 inches and cros6h~ad 6peed of 10 inches per minute conducted at 262C on 12 inch long by 0.75 inch wide ~trips cut from thi~ plate with the fiber direction parallel to the 12 inch dimension ~howed the composite could be drawn S0% without bre~k~ng, predict~ng a high degree r~f formability.
Example 12 Sliver from Example 9 was re-broken to reduce the fiber length by passing it through two 6~t~ of elastomer coated nip rolls with ~ separ~ion o~ 2,50 inches ~etween the nips. The surfaGe ~peed of the 6econd set of roll~ was 10 yard6 per ~nute ~nd the 6urf~ce peed of ~he first ~et of roll6 was 7.1 yaras per minute giving a draft of 1.4. Denier of thi~
re-broken sliver was 4623 and the ~verage fiber length of fifty measurement~ of thi~ zliver was 1.33 inches ~6horte6t 0.6 inch, longe~t 3.1 inche~.

lB
A warp was prepared from 'chi~ sllver by winding ~t, 13 ends to the ~nch on an îB inch ~quare metal plate. A 3.0 mil thick Pilm of thermopla~tic resin (PETG copolye6ter) wa6 plaeed on th~ fr~e before winding the 61iver and another w~ add~d ~ft~r winding was complete. Th~ entlre sandwich wa6 vacuu~ bagg@d at 220C for lS minu~es ~fter which ti~ it w~ cut from the frame. ~hi~ product, c~lled a pr~for~ was now a well-impregnated, relatively 6tiff matrix~Gtretch-broken sliver 6andwich, in which ~11 the ~li.ver~ were ~liqned $n one direction.
Seven of the~ preforms wer~! ~tack~d on top of one anoth~r with all the fiber~ ln the ~ame.direction~
Thi6 st~ck was heated in ~ mold ~t 200C ~t 400 pounds per fiquare inch ~or 30 ~inutes to make a well-con601idated plate ~0 mil~ thick and fiber volume r~ction of 50%. ~igh temperatur~ t~n6ile drawin~
tests, ~t a guage length of 10 ~nche6 and a cro6shead ~peed o 10 inche6 per minute, conduct~d, ~t 262C, on 12 inch lony by 0.75 inch wide 6tr;p~ cut from this pl~te with the ~iber direction par~llel to the 12 inch di~en~ion ~howed the ~omposite could be drawn 50 without br~aking, pr~dicting ~ h~gh degree o~
formability.
Example 13 A pre-laminate was prepar~d from glass fiber from Example 2 by a con~nuous proce6~ as follow~:
46 end6 of sliver were ~ed ~rom a creel into a 6 inch wide warp wh~ch w~s ~andwiched between two 1,0 mi} PET
poly(ethylene terephthalat~) film~ to ~ive ~
pre-l~minate of 55% fiber volume fr~ction. ~ release film of gapton* polyimide wa~ pl~ced on each side of thi6 sandwich to prevent ~ticking o~ ~olten P~T to hot sur~ce6. ~hi~ ~andwl~h wa~ then p~6ed a~ 10 ~elet per ~inute through the nip of two ~teel roll6 h~at~d to 27BC to tack the afisembly together.
* denokes trade mark 1~ , .

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:~ A composite plate was ~ade from thi ~; pre-laminate by removing the release film, ~r~mming the excess PET from the edges and placing ~trip~ of :~
pre-laminate in layer~ in a 16 in~h square ~old. Each S layer was ~ade up of 6ide-by 6ide ~trip~ sf pre~lamin~te to reach the required 16 inch ~idth.
A plate was made from 10 layer~ o~ pre la~inate ~:
by arrangin~ them so that the direction of the stretch-brok~n fibers were off~et by 45 degroes in a 10 clockwise direction in ~uccessive layer6. The botto~ plane of the fifth layer w~& con6idered ~
reflecting plane and the next five layer6 were ~tacked ~o th~t the warp directions of the ~tretch-broken sliver . were mirror i~age~ of the ~op five layer~ with respect to that plane. ~his 6a~dwich wa5 ~old~d a~ ~n Example 2 to ~ake a well-consolidated compo6ite pl~te with ~ fiber volu~e fractio~ of 55%. This plate wa6 heated to 280C
~nd molded into a hemi phere with a radiu~ of 3 inches.
The plate conformed ~ery well to the ~hape ~f the mold ~nd it was concluded that the product was formable.
. ~xam~le 14 A plate was ~ade from 1~ }ayer6 of pre-forms ~ade by the method of Example 11 by arranging them in a 16 inch ~quare ~old ~o that the directlon of the ~tretch-broken fibers were off6et by 45 degre2s in ~
clockwi6e direction in ~ucces~ive l~yer6. The bottom plane of the fifth layer was considered ~ reflecting plane and the next five layers were 6tacked so that the warp directions of the 6tretch-broken ~liver w~re mirror ~a~e~ of the top ~ive layer~ with re6pect to that plane. Thi6 sandwich was ~olded as in Example 2 to ~ake well-eon601idated compo~ite plate with a ~iber volume fraction of 55~. This plate was heated to 280DC and ~olded into a hemisphere with a r~dius of 3 ~nches. The plate conormed very well to the ~hape o~ the mold ~nd it wa6 concluded that the product wa~ ormable.

Example 15 ~:~ Continuous fila~ent 2000 denier c~rbon fiber was made into a warp, preforms nd a unidirectional plate by the meth~d of Example l. The end count was 25 per inch, the film was 2.0 mil thick film o~
thermopla~tic resin (an amorphous polyamide copoly~er ba~ed on bi~para-aminocyclohexl) methane)~ Seven preform~ wele stacked to ~ake the plate which was 55 ~ils thick and 55% fiber vol~me fraction. The plate wa~
~ cut into 0.5 ~nch ~trips, pr~vided with aluminum tabs and ~ubjected to tensile tests at 8 inch g~uge length with the ~ollowing re~ults: -Tensile ~trength, p~i. 243,200 Mo~ulu~, psi. 1~,200,000 It w~s concluded that the product bad very high ~trength ~nd modulus.
Example 16 ~ warp was prepared from 61iver from example 9 by winding it, 21 ends to the inch on a 18 inch square 2~ metal plate. ~ 2.0 mil thick film of thermoplastic resin tan amorphous polyamide cQpolymer ba~ed on bis(para-~minocyclohexl) methane) wa- pl~ced on the ~rame before windinq the ~liver and another wa6 add~d ~fter ~inding was complete. The entire ~andwich wa~
vacuum bagged ~t 280C for 20 ~inutes after which time it W~fi cut from the ~rame. This product, call~d a preform was now a well-impregnated, rel~t~vely ~ti~
matrlx/6tretch-broken ~liver 6andwich, ~n which ~ll the 61ive~6 were aligned in one direction.
Seven of these preforms were stac~ed on top of :
one another with all the flbers in the 6~me directi~n. ~ ;
~hi~ ~tack was heated in a mold ~t 305C at 600 pounds ~:
per 6guare inch for 40 minute~ to make a well-consolidated plate 58 mil6 thick and fiber volume fraction of 55~ One h~lf inch strips cut ~rom this 2~

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1 3265q ~

plate were subjected to tensile te~ t 8 inch ~auge length wlth the fo11Owing re~ults:
Tensile strength, p~i 246,000 Modulus, psi 18j800,000 The uniformity o~ orientation of the iber~ on the ~urface of thiG plate were ~ea~ured fro~
photomicrogr~ph and it ~a6 found th~t 92% of the fiber~
were within + 5 degrees of the ~xial direction. ~he product of this example, ~lthQugh made of di6continuous ~t~ple f$ber, was equivalent to the ~trength and ~odulu~
of continuous filament fi~er (~xample lS).
Example 17 Continuous filament 6700 denier glass fiber was made into a warp, preforms an~ a unidirectional pl~te by the m~thod of Example 1. The end count wa~ 15.5 per ~nch, the fil~ was 3.0 ~il th~ck PET (poly(ethylene terephth~late)) and 5 prefsrm~ were ~t~ked to make t;he plate which w~ SS% fiber volume ~ractlon. The plate was cut into 0.5 inch strips, provided with aluminum tab~ and subjected to tensile te~tc at ~ inch g~uge length with the ~ollowing results:
Tensile ~trength, psi. 156,000 Msdulus, psi~ 7,300,000 It was concluded that ~he product of ~xample 17 exhibited the ~trenqth ~nd ~tiffnes~ expected Df continuous fila~ent glass f iber .
Example 18 A unidirectional plate wa~ ~ade from pre-laminate from Example 13 ~y ~tacking 5 layer~ in a mold with all 61iver in the ~ame direction and heat.ing ~n ~ pre~s as in th~ reference example ~o giYe ~ final thickne~s of 103 mils~ One-half lnch ~trips cut frolm thifi plat~ were 6ubjected to ~en~ile te~ts ~t 0 inch gauge length with the following resul~s:
35Tensile Strength, p~i 86,~00 Modulus, psi 5,900,000 ~1 .

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22 l 32659 l It was concluded that ~trength and modulus of the product of this example, although no'c a~ hlgh as those from continuous ~Eilament glas~ (Example 17) were ~ar superior to those of randomly ori~nt~d glas~
5 composites of equival~nt fiber volume ~Eraction reported in the literature ( ref . ~. D. Agarwal, 1.. J. Broutman, "Analysis and Performance of Fiber Compo~ite~n p. 92) which are:
Tensile Strength, psi 23,000 Modulus, p~i 2, 400, 000 - `

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Claims

23 1. In a process for preparing a sliver of stretch broken fibres that includes the steps of feeding a yarn or tow of continuous filaments into a tensioning zone, tensioning said filaments to their breaking tension causing them to randomly break, the improvement comprising: feeding a yarn or tow of glass fibres into said tensioning zone and applying a finish comprising a mixture of one part of the diethanol amine salt of C8-C12 monolaurate and a lauric amide prior to breaking the tensioned filaments.