p.1 

OAR Box 1413 

Prepped by Ollie Stewart 

Document Number: 

52) 11-1-52 

Docket Number: 

A-94-52 

Printed 7/9/2008 3:11:22 PM Sheet 52 of 114 
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A 1/A UU U Ufltt/t * w A * / U U 

llll 

United States Patent (i9) 

Seller et aL [45] 

lllllll l l »ui„ 1 U „ «,_,,, n 

US003260006A H 7^""* 

Patent Number: 5,260,006 JJ^J-52 

Date of Patent: Not. 9,1993 

(54] METHOD AND APPARATUS FOR 

CONTINUOUS CASTING OF 

POLYMERIZABLE THERMOSETTING 

MATERIAL 

[75] Inventors: Herbert I. Sefccr, PDtesville; len d S. 

Uagar, Randalhtown; Richard R. 

Badtr, Jr , Annapolis, dl of Md. 

[73) ' Assignee; Nsramar Corporation, Odenton, Md. 

[21] Appl-No J 799,740 

[22] Filed: Nov. 22,1991 

Rdsted US . Appllcstfon Data 

[63] CMuianulaa of Ser. No. 468.921. Jan. 23. 1990*. »Undoned. 

[51] 

[52] 

[58] 

(56] 

Int. CU -

us. a 

».B29C 35/10 

264/2*264/148; 

264/216; 264/236; 264/347; 264/BS; 264/166; 

425/174.4; 425/174.8 * 425/224 

Field of Search J 264/22.25,26. IS, 

264/331.18, 148, 166.216, 236, 347; 425/224, 

174.4.174,8 R 

References Ched 

U.S. PATENT DOCUMENTS 

2.136.422 

2J79.24S 

2,603.141 

2*663.908 

&049.761 

3*091.811 

M8U46 

1521.131 

2J29J2S 

3-mj.a 

3^00.490 

3.801.407 

3.821.337 

11/1938 Fields 

C/194S Muikat. 

7/1952 Seifiietf el sl> .-

12/1953 Maieratl. . 

8/1962 Ytfcobflt. 

6/1963 Hieken. 

1/1970 Daisies. 

9/19X) Duggins . 

9/1970 Duggta*. 

7/1971 Meriu 

8/1971 BMngsleyctaf.. 

4/1974 Qoldswonhyctd 

6/1974 BoncUrkeid. . 

264/331.18 

— 264/347 

264/236 

3,172.197 

3,894.816 

3.90(4168 

3,923,941 

3571.171 

x»njun 

•4^01361 

4/HI*42 

4.133.861 

4,186044 

4.221.253 

4,298.413 

4.314.036 

4.42SJ87 

4,626,117 

4.710.SJ3 

4439.125 

3/1975 

7/1975 

9/1975 

12/1975 

1/1976 

10/1976 

1/1977 

4/1977 

1/1979 

1/1980 

9/1980 

11/1981 

2/1982 

9/1983 

1/1984 

12/1986 

12/1987 

.6/1989 

Katoctil 264/166 

Kato. 

Hanusa . 

Waver. 

OthtaueiaL 

Kato etal . 

MkMuc et »U 

KkaeiaL . 

Kaio. 

Bradley etal. 

Seibeiling • 

Tcare. 

Throne ai d 

Hank. 

Hem etal. . 

Murakami ci aL — 

Ma 

264/347 

-.264/216 

._ 264/216 

FOREIGN PATENT DOCUMENTS 

00368)9 9/1981 European Pat. Off. . 

0246806 11/1987 European Pfeb Off. . 

3943266 6/1986 Fed. lUp-eTOeriMny . 

1491437 7/1967 Franca . 

1497702 9/1967 Fiance . 

4999163 9/1974 Japan. 

53-140362 12/1974 Japan . 

Primary Examiner--Jeffery Thurlow 

Attorney, Agnt, or firm—loots, Day, Reavis ft Rogue 

[«] ABSTRACT 

A method and apparatus for continuous caning of potymernable thermosetting materials oompriam miring die 

materials widi controlled amounts of two er more catalyst groups and pauing said mixture through two or 

more series of heating sages. The initially gelled miv 

ture whieh has not yet undergone excessive shrinkage is 

mechanically isolated from the ungdled mixture. 

19 Claims, 4 Drawing Sheets 
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U.S. Patent Nov, 9,1993 Sheet 1 of 4 5,260,006 

RESIN FILLER 

4 

PIGMENTS 

I 

MONOMERS, 

MODIFIERS, ETC. 

COMPOUND 

MATRIX 

CATALYSTS 

SYSTEM 

1 

^ - U MIXER I 

COMPOUNDING 

SECTION 

CAST UQUID MATRIX ONTO A 

MOVING CARRIER WEB AND 

ESTABUSH LEVEL SURFACE. 

i l CASTING 

SECTION 

HEAT CELLED SHEERS) TO 

HIGHER TEMPERAlllRE. 

I 

(HOLD AT A SECOND7 SOAKINd 

TEMPERATURE THAT IS CLOSE! 

' TP THE PEAK TEMPERATURE 

ATTAINED FROM THE 

AUTOGENIC REACTION UNDER 

ADIABATIC CONDITIONS. 

HEAT MATRIX TO A GELLING 

TEMPERATURE. 

I 

HOLD MATRIX AT A FIRST 

.SOAKING TEMPERATURE EQUAL 

TO THE GELLING TEMPERATURE 

1

 UNTIL THE MATRIX IS GELLED 

BUT NOT LONG ENOUGH FDR 

ITS DENSITY TO CHANGE 

SIGNIFICANTLY 

v CELLING 

f SECTION 

CURE 

SECTION 

»J 

PEEL CARRIER WEB FROM 

BOTTOM OF GELLED MATRIX 

SHEET BEFORE SHRINKAGE 

BEGINS. 

COOL SHEET(S) UNTIL WELL 

BELOW CLASS TRANSITION 

TEMPERATURE (fe m WHILE 

HOLDING THE IIM FLAT. 

COOL 

PHYSICALLY ISOLATE 

DOWNSTREAM CELLED MATRIX 

SHEET FROM UPSTREAM. 

.ISOLATION 

SECTION 

[COOL SHEETS TO ROOM 

TEMPERATURE. 

COOLING 

SECTION 

Ffe.1 

& 
U.S. Patent Nov. 9,1993 

P-4-

Sheet 2 of 4 5,260,006 

v5 
P J 

i D M DI-U i TI U TAIO M ^A1_C^ • 1-i.tL-OU • IJwi U • UXJOIlU^U t 'ITAL\JI *JU 

U.S. Patent Nov. 9,1993 Sheet 3 of 4 5,260,006 

TEMPERATURE OF MOVING 

BELT OR MOLD SURFACE 

/ VTEMPERATURE OF 

' ^ THE MATRIX 

VISCOSITYRELATIVE LONG PERIOD 

OF RAPID SETTUNG OF 

FILLER OR PARTICLES 

— IN MATRIX — 

SETTUNG 

VELOCITY 

TIME 

(OR DISTANCE ALONG BELT) 

h

DURATION 

- OF—• ] 

RADIATION TEMPERATURE 

OF MATRIX l 

VISCOSITY 

RAPID SETTUNG PERIOD OF FILLER 

OR PARTICLES (MUCH SHORTER 

PERIOD WITH RADIO FREQUENCY 

HEATING) 

Rg.4 

TIME *^B> 

4 
TEMPERATURE 

TEMPERATURE RISC DUE TO 

EXOTHERMIC REACTION 

v / l 

CJ 

cn 

so 

ftss 

o 

FIRST 

HEATING 

PERIOD 

1 RRST SOAKING 

(CSJJNG) PERfOO I SECOND 

HEATING 

PERIOD 

SECOND SOAKING 

(CURING) PERIOD 

TIME 

Crt 

sr. 

n> 

• 4 * 

e 

Rg5 

' A - GELLING TEMP. £ FIRST CATALYST ACTIVATION TEMPERATURE 

T B > ACTIVATION TEMP. OF SECOND CATALYSES) 

T c

 ^TM15£) ^ P»K TEMP. ATTAINED 

BY MATRIX REACTING UNDER ADIABATIC CONDITIONS) 

tn 

OS 

o\ 

o 

o 

c 

N 

C 

mm 

i0> 
X c- V\J 

P.7 

l \Jl>J>Jtl.\JsCsU~t mCC JU 

5,260,006 

1 2 

matrix is warm enough io "luck oIT* the polymerizadon 

METHOD AND APFARATXJS FOR CONTINUOUS reaction which then sustains itself by its own heat of 

CASTING OF POLYMERIZABLE reaction ud actually is cooled by dissipating heal back 

THERMOSETTING MATERIAL to thai environment. This process continues until sub* 

i stantially all of the unsamrated bonds of the resin and 

Thb application ia a continuation of application Ser. monomer components nre consumed and the resin is 

Na 07/468,921, filed Jan. 23,1990, now abandoned. cued. The .meld Is then opened niter coding and n 

.ACKORO UK DOFTME D 1 V EOT , O N •X-«^'E3:52tt?2 

I. Reid of the Invention 10 thermodynamic and many other aspects ofthis convenThe present invention relates to » new method ind tonal approach, 

apparatus for continuously easting certain thick, sheet Sueh a batch process has significance shortcomings, 

materials sometimes used ai surface overly, but which It is slow and inefficient requiring n great deal of mate* 

also ean be used, without underlay, such as for a stand- rial handling equipment It presents significant pruibalone restaurant table top. More particularly, the pies- IS lens with controlling the matrUmriformitym the mold, 

ent invention relates to a new method and apparatus for particularly where decorative partides are nsed in the 

continuously casting polynurictbcrinosetting materials matrix. For example, flow patterns and convection 

whieh shrink during polymerization. cunenuinthemstrixcinresaltinnonunifonidtyofd>e 

IL Description of Uie Prior Art decorative pattern. In addition, aueh a batch process 

Thermosetting polymeric materials such as thermo- 20 can present curing problems if the matrix is not healed 

setting rains arv commonly used as surface covering uniformly and, thai, does not polymerize at the same 

materials. Sheets of these materials are oted as decora* sate throughout the mold cavity. The result can be 

tive finishing materials in new boOdmg construction and localized shrinking which may cause cracks or tears in 

remodeling for audi applications as bathroom vanity the final cored material 

tops, kitchen counter tops, furniture components, res- 25 Several prior attempts have been made to develop a 

taurant tables, wall paneling and other uses. The sheets continuous casting technique ea an alternative to the 

een be nude of plain solid colon or can be patterned to batch process for thermosetting "f'Trif1* which shrink 

have tbe appearance of marble, granite or other patterns upon curing. U.S. Pat. Na 3,600490 issued to BQlingsor texture! decoration and often are loaded whh decora- ley etal for example, teaches that if the stmcture cores 

live particles to provide these characteristics. The rain 30 unevenly, ss busil y the case, ocrtnin areas ofthe mass 

composition typtcsDy includes mineral fillers such as will harden and shrink unevenly, distorting the east 

calcium carbonate or aluminum trihydrate. It is pre- product To avoid the problem of wrinkling or tearing 

felted that the pattern in these materials be uniformly an the snrfhee of the matrix during shrinking, Biffings* 

distributed and that the fins) product be flat, smooth ley teaches the use ofa thin film and lubricant to pennb 

and free of warpage. bends or wrinkles. It is also pre- 35 belt of tbe conveyor. Specifically, Billingsley teaches a 

-ferred that n flat surface be obtained with tbe minimum process whereby tbe matrix rests m s layer ofa Am 

of sanding or machining. • which shrinks during besting at the same rate ns the 

The composition ofthese materials typically can be a curing matrix. BOtingsley teaches the use of oil or a 

single thermosetting resin or a mixture ef resins such as similar liquid lubricant between the film layer aad dw 

unsaturated polyesters and acrylic resin precursors. 40 conveyor beh. In this approach, the film shrinks with 

Such resins require a caulyst and/or promoter system the matrix and the thin film does not bang up on the 

to initiate the process of free radical polymerization, conveyor belts as it shrinks. 

Typical resins are characterized by having a significant Another cononuoos casting approach caa be fonnd in 

exothermic reaction during polymerization and a sub- US. Pit. Na 3.9M.098 issued io Kato et al Kato 

stantial increase of density during that process. Thus, n 45 teaches a dual bdt system which uses the force of a 

typical mixture of 65% filler and 35% resin (a "matrix") confined space to control the tendencies ofthe matrix to 

shrinks during the polymerization process so that the distort orseer Itself apart during the polymerixadon 

cured solid composition has a density about 5-7% process. Tbe matrix b passed through a confined space 

higher than the liquid matrix. This shrinkage presents defined by upper and lower belts which force the mstrix 

processing problems related to the present invention SO to maintain a fiat rectangular cross section despite die 

which' are discussed bdow. presence of interns! forces brought about by localized 

A variety of prior methods have been used to achieve curing which would otherwise cause the matrix to pull 

synthetic sheet materials having a decorative pattern, apart, warp or bend. 

One method involves a batch process, hi this process. From the foregoing It can be seen that the prior art 

the matrix is prepared by mixing ibe thermosetting 55 continuous caning processes involve expensive and 

resins whh tbe filler and the desired decorative panicles complicated arrangements lo control ibe curing of tbe 

or coloring materials and a standard quantity of cats- thermosetting material. Prior an casting methods also 

lyst. Tha amount of catalyst typically recommended in pose quaUty problems. In conventional beh casting 

the prior art is one half to two percent based on the equipment the liquid mstrix often is heated by tbe eonHquid resin fraction. This matrix Is then poured or 60 duction of heat through thebdts which are endosed is 

pumped into a large casting mold and sealed in the an environment of heated fluid or gas. With ooavenmold. The mold is then subjected to sufficient heat to tioaal conductive heating, if the mold or belt surface is 

begin decomposition of the catalyst, which initiates too hot, it will cause initiation ofa rapid aooeleruhng 

polymerisation of the rcsin. Because the polymerization reaction before curing la complete. This can cause local 

is an exothermic process, the reaction contributes to the 65 boiling, or at least, irregular cure wim shrinkage 

heat of the system leading to further catalyst decompo- stresses, cracking, ripple, craze layers, etc. If the heating 

sltion and an increased rate of polymerization. Tiiis is done on a single supporting belt (without a top belt), 

follows tbe convective heat environment applied to the tbe bottom of the mstrix layer can polymerize before 

(0 
P.8 

5,260,006 

3 4 

the top, causing severe warp, concave upward. Also. and without transmitting stresses to the softer gel 

excessive temperature differences between the matrix formed during the initial gelling in the firat zone. Acresult in objections] appearance of mottling or streaks. cording to the invention, substantially adiabatic coring 

Thus, the use of convection heal and typical bdl SI'S- oonditiona preferably arc supplied In Ihe second zone, 

terns will result in the need to limit the rate of heating, S The present invention bas the benefit of providing an 

resulting in a long heating time which then requires a efficient uncomplicated method of continuous casting 

higher matrix viscosity, and longer equipment in the Out avoids the creation of intend stresses. It has the 

case of continuous casting. Problems arise because whh benefit ofproviding a means to isolate the curing matrix 

the longer heating time, the viscosity of Ihe matrix is from destructive internal and extemal forces which 

reduced for a longer period of time before It rapidly 10 toad to produce distortion. It abo has the Vrnifh et 

dimbs just prior to gelling. Tills is illustrated in FIO. 1. producing a cured homogeneous matrix with uniform 

Tbe lower viscosity for an extended time permits lhe properties and appearance. It abo h u the benefit of 

mineral filler to settle and also *ny dense panicles used providing individual sheets which shrink uniformly 

to decorative effect may s* ^ resulting in a non- throughout the sheet material thus avoiding warpage, 

homogenous sheet botb m physical properties, and in 15 wjvfaess, or odier signs of irregular ihrinkage during 

appearance at a cut edge. c m even though no externally applied pressure bproSUMMARY OF THE INVENTION -Had. Additional advantages and benefits will be ap-

..-., . parent to thoae skilled ia the an upon reading this dh> 

It is an object of the present invention to provide an closure, 

efficient aad simple method for continuous casting of 20 

tbenaosetting materials which shrink upon curing. It is BRIEF DESCRIPTION OF THE DRAWINGS 

an object to provide a method ^e}^eK***J" FIO. 1 is a schematic flow fflustrstioa which depicts 

problems of particle settlement and surface distortion tk - _-~~« „M «-«««.. *. „-,, —Z^J—.• Jr\tZ 

during the coring process. It u « object to provide a SLEThSSK.^^ ^ to one embodimenl of the 

method which will prevent the creation of internal 15 "TO . 2 fa a diagiamatlc side devational view of ooe 

stresses (and the associated problems of warn, curl and i « Mi^TMTM****. H»«ITHMHI WW wt « n 

whlcbwfilavoythetendeneyorthesbrinkingmatiix J^^?ff^^l^£^t?2jJ ^ 

to detach itsdf due to shrinkage from the Squid matrix ^J? 1* *

 o f

 t " % . * * *J5fiL*fa* ? 

attteenrryeadofthe^m? ^ w matrix prior so the gelling m a ccnvendonal heating 

Addmonal Objects, advantages and novel feamres of "»•?,,TS^^n^SSSL^S , 

the invention wUl be set forthto pan ia the description .r^"'**^3^i^ , T^^z!^. * 

which follows, «,d in pan wfllbecome appaieu to **?**»** "I*-1 £*£ ft "* ?f ^Ti 

those skilled ia the an upon examination ofthe follow. £* • «*••••»*; P 0ttW e b» * • «»P">Y«I ***** «* 

ing or may be learned by practice of the invention. Tbe J$ "epresat invenfitm. 

objecu and advantages ofthe invention may be reahzri , "? • » • • ff* ****** •» «

abo

»

a

*

n <

 jf » • 

and attained by means of the instrumentalities and com* healing sequence according to the present invention, 

binations particularly pointed ont in the appended DETAILED DESCRIPTION OF THE PRESENT 

d

^

W *J .. -. , , , ^ u. A m. . INVENTION 

To achieve the foregoing and other objects and in 40 . ^ . 

accordance whh the purpose of tbe present invention, **•* P*©6*** »*?• «th e present invention are sebethe invention provides a method and apparatus for con- markally illustrated in F1Q. t Aa ahowa in FIO. 1, to 

tinuons casting ofa polymerizablc thermosetting mate* hegin, •""

 m •,,is

,

i ,

 W*** """f • •mixture of resin, 

rial which shrinks upon curing. According 10 the pres-

 fiDer *** opdo*mtf inononiera, modifiers or other tngre^ 

ent invention, the thermosetting composition Is mixed 45 dbnts. The matrix is then prepared for casting with the 

using a controlled amount of a first catalyst having a addWon of pigmentsand catalysts. The decorative sheet 

limited activation temperature and a second catdyst naterial may be made of any thermosetting material 

hsvwg a sufllcitnily higher activation temperature. The *«*•« the desired properties of beet resistance, color 

matrix fa then deposited in a controlM amount on a stability, clarity, domical and stain resistance, aad 

single layer web which is traveling on a conveyor or SO other physical properties snitabk for easy mtchinsbiliiy 

ever a fixed support plate. The matrix, which is fas a and fabrication hs the polymerized (bra. Hie present 

liquid state, is allowed to travel br enough to allow the invention is particularly weU suited lo materials which 

top surftce and edges 10 become level and smooth, shrink upon curing. Such thermosetting materials are 

According lo lhe present invention, the matrix is ibea discussed ia greater detail below. 

heated fat a first zone to a temperature lhat initiates 55 A oatdyst system typically consisting of two or mors 

decomposition ofthe catalyst having tbe limited active- catalyst groups it used. The catalyst groups aro selected 

tion temperature. It hat been found in accordance whh such that one catalyst group has a limited activation 

the present invention Ihal the mstrix esn be made to temperature aad the remaining catdytt group(s) have a 

partianypdymeriie to a rubbery gd quickly in the firat -sufficiently higher activation tenipcistitfc. Typically, 

zone without excessive shrinkage. The gelled matrix fa 60 each of these groups oomp:rfses only a single catalyst but 

then mechanically isolated from the Uquid matrix near can be made of two or more catalyst la a group. It fa 

the entry end. The gelled and isolated matrix is then critical for performance that tbe difference in temperaheated ia a second zone to a higher temperature that ture between ihe lower activation teaperature caulyst 

initiates decomposition of the second caulyst, which group and the next higher activation temperature catabas a sufficiently high activation temperature Accord* 65 lyst group must be si least 10 degrees fthrenhett. The 

ing to the present invention, it has been found that the preferred diflerence is al least 30 degrees and. in the 

isolated gelled matrix can freely shrink in the second preferred embodiment, Ibe difference is at least 50 dezone without causing wrinkles on the bottom surface greet. 

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P.9 

5,260,006 

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The activation temperature of the first catdyst group which take place later in the process. As explained 

should be in the range of 100 to 220 degrees F. The below in greater detdl, this it done in two steps in the 

activation temperature ofthe next higher catdyst group preferred embodiment. First the carrier web is peded 

ahould be in the range of approximately UO to 280 from the bottom ofthe gelled matrix. Next, the gelled 

degrees F. The preferred range for this second group is 5 mstrix n physkdly isolated from tbe upstream matrix. 

ISO to 2B0 degrees F. This may be done by a variety ofmethods such as pinch 

A variation on this method uses s single temperature rollers or, in the preferred embodiment, by cutting the 

activation ofa portion ofthe catalyst (the first catdyst continuous gdled sheet into predetermined lengths 

group), having another portion of the catalyst (the using a traveling saw. 

second catdyst group), to activate at a suffideatly IO The isolated gdled matrix fa theo heated to a second 

higher temperature. For purposes of this discussion, any temperature. The second temperature is sufficient to 

such method which involves caulyst activation at two aeti ^ aMtt mare of tbe remaining eatalystt groups 

or more different staged temperatures will be included sodthei^imtktcanacoeleraiodpol'ymeritaiionraacwithin tbe definition of the caulyst system of the pres- tioo which reaction generates heat to the preferred 

*cnt invention. IS embodiment, the matrix b then held at a second soaking 

Il fa abocritkd that the amount of the catdyst hav. temperature approximately equd to the peak temperaing the lower activation temperature be limited such ture obtained fiom Ibe heat of this second reaction 

thu the lower tempenture catdyst group win bring under adiabatic conditions. The matrix ia held at this 

about a proper amount of partid polymerization ofthe temperature at least until the shrinkage fa substantially 

matrix. The minimum amount of lhe lower temperature 30 complete. In the preferred embodiment, it fa hdd at this 

catdyst group selected is the amount sufficient to cause temperature until the desired polymerisation fa oomthe matrix to polymerise to a rubbery gd before it has ptete. 

reached the point in tiie process where the matrix is Findly, the sheets are hdd fiat and cooled untO wdl 

mechanically isolated from the less polymerized matrix. bdow the glass transition temperature of the matrix 

As on upper limit, the amount ofthe lower temperature 25 materid. In cooling a relatively thick sheet of plastic 

caulyst group should be held below the amount .which composition, unequal shrinkage stress "may occur 

would cause excessive Shrinkage of the matrix before it through the cross-section due to the fact that ihe surfoce 

has leached the point in the process where the matrix is of the sheet must cool before the center. If the cooling 

mechanically isolated from the less polymerized matrix. is slightly asymmetrical from one race to the other, the 

ExcettivesluulugefathataiioumwliicKinthecaseof 30 sheet cast warp or curi during coofing. which warp or 

the given matrix, causes the matrix to form surface curl can be permanent Thus, during the cooling phase 

wrinkles, resided stresses, warp or.ln extreme cases, to it is preferred to hold the sheets flat until wdl bdow the 

tear itself apart Thus, the quantity ofthe lower temper- glass transition temperature, 

ature catdyst group preferably is no more lhan lhat The preferred method of beating is by a radio frowhich fa Just required to bring about a rubbery gd 35 queney field. By this method* the Squid matrix can be 

under the selected first hearing conditions As explained heated very rapidly without local teaperature variamore fully bdow, it has been found that the matrix may tion! that cause objection*) flow pattens. Aha, probe paniaDy polymerized to the point of creating a solid vfded hot spou due to Interference nodes an eUmlrubbery material suitable for further processing in ac- nated. ihe upper temperature limit during gdling ean be 

cordance with the invention before an excessive amount 40 raised without idtiating •K^P**-* premature autogenic 

of shrinkage occurs. The amount ofthe lower tempera- reaction. Thus, a shun heating section* less restrictions 

ture caulyst group, expressed as percent sctive of cau- on matrix viscosity, negligible settling of filler, and 

lyst based oa the liquid approximsldy 0X1010 snd 0.02 exedient healing conlrol dynamics art obtained, 

percent gives a conventiond matrix composition and Oso embodiment ef sn apparatus according to the 

oven parameters. The preferred range is between sp- 45 present invention is shown in FIO. 2. Tbe casting appaproximatdy Q0O13 and OSH. This fa discussed in greater ratusofFI0.2may be divided into two general sections 

detail below. for purposes of dlscusrion, The first iaa aectico in which 

Retunung; toFIG. I, the liquid mstrix with the added tiie mstrix Is cast and initially gdled The second is a 

catdyst system is dispensed in controlled smounu onto section in which the matrix to fully polymerized and 

a moving carrier web aad moved a sufficient distance to 50 cooled. These sections are divided by a means which 

establish a levd surface In the next step of tbe process serves to isolate the transmission of mechsiucal stresses 

depleted in FIGS. 1 and 5, the matrix is quickly poly- resulting from tutrix shrinkage from the gelling stage 

merited to the point where it creates a solid rubbery gd. of the process. 

ln ue'preferred embodiment, this is accomplished by Viewed from left to right, tbe present invention proheating the nutria by radio frequency energy to a first 55 vides an unwind roll 2 which carries s web 4 upon 

tempenture (tbe gelling temperature) and holding the which the matrix is cast In ooe embodiment this web 

matrix at a aoaking temperature equd to thai tempera- oonsUu of a release coated roDoTpsper, but it couJd be 

tore for a -predetermined length of time. The first tem- any manner of travding surface such as a properly 

perature fas temperature sufficient to activate the lower treated conveyer bdt To tbe right ofthe roll 2 there fa 

activation tempenture caulyst group but aot high 60 provided a conveyer platform 6 which runs the entire 

enough to activate tbe second catalyst group. The ma- length of the first section of the apparatus. Tha cootrix is held at this temperatbre until the matrix has be- veyor platform 6. provides a surface aeroaa which web 4 

coma a rubbery solid but has not yet had an excessive fa pulled In the anting process. The conveyor platform 

change in iu density. Activation temperature is the 4 in of a sequence of flat saptempereture at which the catdyst rapidly decomposes 65 port surfaces made of sheet metd or other materid 

in resin and initiates a polymerization reaction. suitable to ihe environment. The portion of the surfoce 

Next, the matrix is manipulated to isolate the gelling in the radio frequency cavities described below namsection from the transmission of shrinkage stresses idly mutt be nude ofa radio wave transparent materid 
^ P.10 

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 r 101-60*1040*'»toi ov 

3,260,006 

7 8 

such as plate glass, polypropylene, glass reinforced tion snd without causing shrinkage that can cause the 

silicon resin and others. carrier web to ripple or wrinkle before it is peeled off by 

At the entrance end of tbe conveyor platform, there rolls 20,22 and 24. 

is provided an apparatus for folding sharply upright the Web 4 then advances through exit interference choke 

edges of the paper web 4 lo form vertical edges of a 5 16 and through isothermal soaking chamber If which is 

predetermined height. This causes web 4 to take the maintained at the same first temperature throughout its 

form of a continuous pan. It wQI be obvious to those length. In this manner, the combination of starting resin, 

skilled in the sn that other means could be used to catdyst, first heating temperature and rate of advance 

provide appropriate edges to the weh to reuin the ma- ofthe web can be adjusted ro provide a firm rubbery gd 

trix. Doumatream ofthe folding apparatus there is pro* 10 exiting tha soaking chamber If which gd has not yet 

vided a eaating head g for the liquid matrix. Down* undergone excessive shrinkage, 

stream from the casting head t there fa provided a con- The geUed matrix sheet 42 carried on the web 4 

vemioad radio wave interference choke 20 which pre- emerges from soaking chamber II into tbe bobdoa 

ventt the radio frequency energy from leaking out Into section. There, the web 4 fa peeled from the bottom of 

the room. The interference choke 10 is attached to a 15 tbe matrix sheet 42. Then trsvding saw 24 whose mafirst heating cavity 12. As mentioned above, in tbe re- chine dircctiond velocity fa carefully aynchronisad 

gion ofthe heating cavity 12 the conveyor platform 6 fa whh the web 4 velocity, makes a transverse cot through 

constructed of a radio wave transparent plate. The the matrix 42. Tbfa separation by cutting is a preferred 

heating cavity 13 is appropriaidy blankatad with mart method of physically isolating tha dalicat-a aad deform*-

gas through inlet 14 to avoid the possibility of igniting 20 able portions of the gelled matrix from shrinkage 

flammable gases due to the potentid electrical arcing. stresses produced in the downstream curing step. Tiiose 

To the exh aids of the heating cavity there is pro- skilled in the srt will recognize that other methods of 

vided sn exh interference choke 16. Adjacent to the exit providing physicd isolation are abo possible.' 

interference choke 16 there fa provided a first bother- In this embodiment, the individud gdled sheets 44 

md soaking chamber 14. Thb b constructed such that 25 are redeposlted on the moving web 4. The web 4, now 

die temperature of Ihe environment surrounding the loosdy supporting flu gdled duett 44, advances into 

matrix is uniform on all sides, including the bottom the second heating, cavity 32. Here the gdled sheet 44 fa 

which hass beating duel below the conveyor platform heated to s second temperature thai activates the re4. mamlngcatdy^ Thb initiatm a reaedoa ofthe partially 

Just beyond the exit end of the first faothermd soak*- 30 pdymaized rcsin which, as described below. Is carried 

ing chamber 14. a aeries of non-driven rollers 20,22 and out approximaidy adiabstically. The polymerization 

24 fa provided beneath the pisiform < In a configuration causes the temperature of the gelled mstrix 44 to rapidly 

which draws the web 4 away from the gelled matrix. In increase to a peakvdue. This peak value depends on the 

the region where the matrix snd web are separated, degree of polymerization when lhe reaction begins, the 

there b provided a traveling saw* 26. 35 concentration of resin m the matrix and the heal capacDownstream of die traveling saw 26, there is pro- hy ofthe matrix, 

vided a second section of conveyor platform 24. Jun The rapidly curing matrix 44, after exiting choke 34, 

beyond the second section of conveyor platform 24, enters the soaking chamber Ml Thb chamber SI fa mainthere fa provided a second radio wave interference tamed at approximaidy the same temperature as tlie 

choke 20 adjacent a second heating chamber 32. Agdn. so expected peak temperature of the exothermic curing 

the heating dumber 22 is appropriately blanketed whh / reaction in order to provide sn adiabatic reaction enviinert gas through inlet 34. At the exit aide ofthe second \ ronment That is, since the surrounding gas and supbeating chamber il there fa provided an exil interfere porting members in the chamber 21 are hdd to the same 

ence choke 36. Adjacent to lhe exil Interference choke temperature as the expected peak of the curing matrix 

24, a second soaking chamber 24 b provided. Down- 45 sheet 44, the matrix effectivdy fa in thermal isolation 

stream of the second soaking chamber 34, there fa a from itt environmetM during ihbsoaltingand.pdym^ 

cooling section. ~ zitfon process. Thb providesE a uniform tereperarure 

In the preferred embodiment, operation of the appa- profile te sD directions, uniform cross-sections! shrinkrates of the present invention proceeds as follows. A age and mhtlmiiation of warps, waviness aad unbalrdease coated paper sheet 4 is pulled from tbe roll 2 and 50 anced stresses. 

threaded through the entire length of ihe equipment Hne The present invention relies, in part, upon eertsin 

to the motorized rewind roll 40. As the web 4 advances, -relationships fat tha shrinkage and polymarizstioa propjust prior to tbe entrance to ihe easting section, ibe erties of thermosetting resin materials and thdr catsedges ofthe web 4 are folded Sharply upright to form a lytu systems dbcovered'io be advantageous in the conmoving trough witb verticd edges. 35 tinueus casting of thermosetting materials. Various msA liquid matrix 42 ss described above b pumped at a teriah were used in the work reported snd tha msteriab 

constant flow rate through the casting head I onto the ofthe present invention are characterised as follows but 

moving web 4. The relationship among the matrix flow are not meant to be limited by the folbwit^ deacriptien. 

rate, the web velodty and tbe web width csublbhes the Those skilled ia the art will recognise tbe various 

sverage thickness of the liquid mstrix 42. The web 4 CO classes cf thermosetting materids which ean be used in 

advances a sufficient length to allow tbe liquid matrix accordance-with the present invention. 

*42toflowtoalevdsurfkee.Theweb4thenentersthe ^ ^ ,_ . 

first heating cavity 12 through the interference choke Polyester Kesu 

10. In that heating cavity 12, the liquid matrix b heated Aa unsaturated polyester easting resin fa prepared by 

to a first temperature selected to activate Ihe lower (5 a condensation reaction of dihydric dcohol snd dibarie 

temperature caulyst group and cause polymerization to adds. The viscous reaction products are then dissolved 

a gd state without causing premature initiation of the in vinyl or acrylic monomers auch as styrene, vinyl 

other caulyst group(s) or a strongly exothermic rcac- toluene or methyl methacrylate (MMA). Tba resins 

9 
PJJ_ 

S.260,006 

9 10 

used contained about 30% styrene monomer, about 50% to 65%, the lower ratio, of course, bring the most 

0-15% MMA monomer and have a viscosity of about difficdt rebtive to heat of reaction. The lower pre500 to ZO00 cp at 20 degrees C. ferred ratio of ATH b approximately the minimum 

These resins typically contain a small amount of in- concentration that still provides good fire-hazard charhibhor, such as hydroquiaone to prevent premature 5 actcristics suitable for building applications, but lower 

gelling during storage. They also typically contain and- ratios could be wed irfireresbunceb or no concern, or 

oxidants and UV absorbers to help contro] aging and if other means are used to provide fire resistance. 

UV degradation ofthe cured parts which cause yellowteg, embrittlement and other physical deterioration. "HI-POINT 90" (Wlteo Chemical Co.) 

The spedfic resins used, are purchased from commer- 10 Methyl ethyl ketone peroxide (MEKP) fa a catdyst 

cid resin suppliers and their exact composition fa pro- typicaOy nsed m initiate free radicdreaetioM in polyesprieury to tbesupplier. However, tiiose found patticu- ter resins. When it b used stone in the resin, it begins to 

Isrly wdl suited to be adapted for use in ihe present decompose st s fairly high temperature above 200* P. 

invention have the following characteristics: (1) They When •$*& n^h • w*m\} **«$** efmrttl mvfll\r,mtt 

can be polymerized td a thermosetting sute by a free 15 or octoate. however, MEKP resets st lower tempersssdicd reaction ndtiated by catdysts; snd (?) The den- rum. Thus, polyester resin containing about 1-2* of 

ally of the cured redn fa substsntidly higher than the MEKP, snd shout OuCH% copper msphihenate hat been 

Squid resin. le , the redn shrinks during curing. Ao- found to gd in shout 30-60 minutes at 80* EF, aad in 

cording to published and measured densities, fhe an- about only 5 minutes at 150* F. It fa auppSed aa a 50% 

filled resin typically can shrink up to about 15% during 20 active mixture dbsdved in dimethyl phthalate. 

polymerization of polyester snd up to about 20% in the 

case of unfilled scryHc resin. The mixtures of resin sad "USP-245" (Witco Chanted Co.) 

fifler med (about 35% resin snd 65% mineral filler) 2^dimethyW,3 bb (2-etbyl-bexanoyl penny hextypically increase in density about 3-8% from tha liquid ene) b a liquid catdyst that decomposes rapidly in pOlymatrix to the find cure. Thus, if the shrinkage occurs 25 ester reste mahout 180* F. It beupphed as s*0« active 

faotropteauy, LC, the same amount in each direction, a mixture, 

volume shrinkage of 7% would be rautrd by linear 

shrinkage of 244%. Lower filfcr rates wiU have corre- "PERCADOX 16" (AKZO Chemicals Inc.) 

spond ^ higher shrinkage. ..... . DH^Jmiyl-cydohexylHieroxy dkarbonate fa a 

In the esse of a mineral-filled retin matrix in which 30 po^e, „ « dj^ ^ h „,„, * ^awne,, .nd dee0m. 

the filler has a substantial heat capacity, much of the p^* ^j y fa the min st about 110* P. It has been 

freemagy change dunngpolymerization results m an f ^ to fftaoee , ^ „„ , ^ ^ ^^g , „ 1Jn. R 

facmsed temperature tf the filler as wdl as the win. and thus Su be used as en alternative to tbe oembins-

* * w , fc^J l,lft ^ . , d ^ ^ t e *

c

^ " : m donofME»andcobdtnuphibenate.ltissuppHedssv^^Idbecu^lemsressonabfysbortperiod 35 mi(»%activelngiedi«t.In^pmemhrvenri^this 

during.which the find cure is conducted in an osen. b , ^^^ lo w .enqwwwe catdyst. 

tiaHy thermally isolsted environment without the inter-

 r 

nd heat of reaction causing enough temperature rise to "TRIGONOX C (AKZO Chemicals Ine.) 

csurethermd degradation of the pdymer. t^tyliwroddcbenzt^ba^uldthatdecooinoses 

Aluminum Trihydnie (ATH) rapidly fo polyester ai about 250'F. It fo supplied as an 

. . . —_-. . ..-„ . . .. „ , .•' 100% active ingredient In the present invention, thb fa ArumhumTrih^ntctATWbsnatu^yoccuntog t preferred h $ tempcreture eitdy*. mineral derived from processing of bauxite ore used In •»- —»— # 

the manufacture of aluminum metal Its molecular for- EXAMPLES 

^fa^0j3bl3HA^fatepure.refteedsute . 45 ^peeu of the present invention are diown by the 

findv"^? ^5ftT£!!3SKl S « I folIowteTex-nplm for purpous of illustration. These 

|fa«y ground form,j^TH hasb^^Wdy used as a ^^^ and embodimentsare not meant WlimH the 

filler fa plastics lo improve fire resistance. It b most fc,v«,Uon fa any way. Those skiDad In she art will rec1 ^ :

^X^^^^^Si ^ " ^^withlntiieHdrit^scopeoftheteveotion. 

tite viscosity of the resin- ATH msuto That is, as the EXAMPLE 1 

ATH particle sta faMred»ced JtsJiighei.surface area ^ A ^ ^ mlxWre h „,,, ^ ^ 

resdis in incressed viscosity of the matrix, making it 

lets suitable in the present invention. At above about 55 

20-50,000 cp, it becomes very difficult to process, pump 

aad pour the -matrix. With a desired mixture of 65% 

ATH, 35% redn. this vbeoslty range occur* with ATH 

particle sine of about 10-20 microns depending on the 

processing conditions and the particular brand of ATH. 60 

The high practical limb of particle aze would be determined by its settling rate and thus b dependent on the 

concentration in the resin and tbe gd time of the matrix. 

For 65% ATH. 35*%" redn mixtures, it is preferable in The resin, the MMA monomer conuinlng the cobah 

the present invention that particle size not exceed shout 65 promoter and tha ATH are mixed under vacuum to 

30 microns. obtain a uniform mixture of about 6-12,000 cp. free ef 

The preferred filler ratios are from about 40% to sir bubbles. The fast two catalysts are added and sdrred 

about 15%, snd the more preferred ratio is from about until uniformly dispersed. A silicon resin-coated paper 

UMiiurutd poiycjicr min 

Cobalt aaphdicMit PIMBMW 

<U« aaive) 

MahyiMdMcfybitartavMr 

ATH pewter 

Moby! ethyl ktioit |nwilde 

caitlya (SMI Kth*) 

-USM45" auJya O M active) 

304 *awtk 

O.I puts 

44 rem 

610 puo 

141 put. 

OJS parts 

10 
Tfcnw^/^t^ 7~, W?W ^ 

*JI_.- ' i u » UT7^7777I^73II7 . ,-ir35'T' ,

l 0 :23 : ,

;

 - 19199410234:327/50 

5,260,006 

11 12 

is folded into the shape of s tray about 8" x8"x I" high, surface badly wrinkled, as b the carrier paper when it is 

with the comers taped together and with the release peeled from the cured plastic sheet. It is observed tbst 

surface inside the pan. The paper tray is placed in a the resin b shrunk with the mstrix still adhered 10 the 

polypropylene pan ofa size that provides support to the crier web, resulting in a badly wrinkled bottom surupfolded edges of the psper tray. The mstrix b poured 5 face. It is obseived that the ftabhed sheet that emerged . 

into ihe paper tray to form s byer about I" duck. The flom the end of the second heating zone it badly 

matrixiRiled trey snd support pan are then placed ma warped and conldns crsclu and lean, mostly oriented 

WO^microwaveoven. • . . • . ia themschine direction. 

The oven is energized for a long enough time so that 

the matrix temperature rb« after several intnutes to ISO io EXAMPLE 4 

about 5 minute, the temnvatiirc ef the cdlad matrix Example J is repeated except that ihe microwave 

exc«d,250-F,c.uscdbythe«oihcrmicreactlcn.The ^S^SiX l ^S£?^ S ££!?2i5?? I 

matrix is dlowed to cure far 35 minutes and then re- v^^j'J^A^1^^^Tf!±c^

b

t 

moved from thepspertray. It uobscrvid that thecwed JJ about 150 degrees F. It is observed thu the materid 

part is smaller than the origind size ef tbe tray. The

 emer

»

i n

« •*•• * e first cavity fa slightly soft to tbe 

bottom surface of the cured matrix and the bottom «ow*butsolid enough to handle. As the paper is peeled 

l^per surface of the paper tny are both severdy wrin- from the bottom ofthe rubbery matrix sheet, it fa obkled due to shrinkage of the matrix while adhering to served to be relstivdy smooth and free of wrinkles. Just 

tbe paper. 20

 after

 ** W ** Pee*

ted fron ** gdled matrix sheet, 

' the sheet b cross-cat by the traveling MW, sad flie reEX AMPLE 2 suhmgsectfonitredepositedonthemovfagpaper.lt 

Experiment I b repeated except that the microwave then travds through the second heating cavity, the 

oven is turned offat a time when the matrix temperature curing oven snd through s cooling zone. In the second 

reaches about 140-ISO degrees F. After about 7 minutes 25 heating cavity, the plastic sheet is heated to about 250 

it is found that the matrix fa gelled sufficiently to be degrees F. 

handled snd can be pulled from the paper. It is immedi- The finished cooled plastic sheet is observed to have 

ately'returned rothe paper, placed back in the oven and a smooth bottom surface. It dsob dso observed to have 

heated to above 120 degrees F to complete -the cute, a series of lengthwise parelld peaks and valleys on the 

agafa b about 35 mmutes. This cured, shrunken part is 30 upper surface, witb dm peaks as snuch as about 6O>70 

removed from tbe trey. It fa found to have a smooth tnifa higher than the troughs. Abo. lhe finished sheet fa 

bottom surface, free of wrinkles. The paper tray dso fa subsuotially curled fa dtecross-mschfae direction, indifree of wrinkles. Little or no machining or sanding b csting lhat the sheet developed stresses during curing. 

required to provide a flit, smooth surface- The cress«achlne direction apadng of the ridgea fa 

EXAMPLE 3 ** obsen«dto*coiitipoi»dtoTiot^oti"inilieflriiheat-

* * u~.u . 1 1 _ «. J «.« frf ctvHy» *Wd» locally heat the liquid matrix to a 

A. A liquid mairixmlxture fa prepared as follows: te^tnr e above IgO degrees F, ile a ibough the 

avenge temperature is only about 150 degrees F. These 

localized temperatures are observed to be above tbe 

rapid decomposition point of tbe higher temperature 

caulyst 

EXAMPLES 

The above mixture fa mixed at high shear under vac- Meul paneb hinged at their lop are hung about 2" 

num until a uniform mixture b obtdned free of ab bub-

 5 away from each vertical wall ofthe microwave cavity 

bles and has a viscosity of about 10,000 cp. The mixture and parelld to each corresponding wall. Means are 

fa pumped at a steady rate of 22^#/rdnute uto a con- provided to swing the bottom.of esch pand back snd 

tfouous mixer to which Is introduced ai7l#/minuteof forth m an are about 4" long. When the panels srs fa 

a caulyst mixture: motion, the radio wave nodes caused by multiple faterad reflections sre caused m move fats random pattern. 

•yggf -.-- The formulation and running conditions of Example 

-LUPERSOL w nj * 4 are repeated, cmca with the pands still and onco witb 

-TJSMSS" u.t*9 the paneb moving, fo each case, across-machine direcg tion temperature profile ofthe gelled matrix n recorded 

Thb provides a concentration of caulyst in the resin «** «"* « *** * • *?*&••? * P e T - - *•* * 

fraction of the matrix of about 2.1%. Thb mixture fo after eeoltog, sre exsnuiied for the ridges described fa 

east from a dot onto a moving paper web, as described Example 4. 

above fa connection with HO. 2, whh folded edges 32 Wtt the panels not moving; ihe crou-meekine diree 

bi. apart and moving at 2.0 ft/minute. Thb resulu fa a 60 tion temperature profile Is observed to have peaks and 

liquid layer having an average thickness of about 0-50 *a*aejfa whh an amplitude of about 70 degrees F. Tbe 

inches. cured sheets contain severe ridges about the same as fa 

The energy output of the first microwave heating Example 4. When the paneb are caused to reciprocate 

cavity fo set at about 32 KW. The matrix temperature at a* me of about 15-20 times/minute, (he amplitude of 

exceeds 110 degrees F at the end of the first heating 65 the temperature profile is about 15 degrees F, and the 

cavity—a temperature which exceeds tbe activation severity of the ridges fa the cured sheets b sharply 

temperature ofthe "USP-245* catdyst The hardened diminished. However, the theeu still have substantia) 

sheet emerges from the first cavity with the bottom curl in the cress machine direction. 

/I 

UwaturMrd pelytSlfr Ntb 

Cobalt maphtbeniir promoter 

ATH pcrdtr 

JS.S 

as 

JUL. 

ns 
P.13 

^i_i >i ui - wo i i v inii_Mi oni_i_o I ~lii"c»VJ i3iaaiiu^4:»20/:»u 

13 

EXAMPLE 6 

5,260,006 

A matrix b prepared using tbe formulation of Example 2, but with a caulyst mixture as follows: 

209b TERCADOX-16- S 

1% "TRIGANOX-C* 

89% Styrene 

When thb catdyst mixture b added et a rate of 0.263% 

"PERCADOX" fraction on the resin fraction of the 

Squid matrix, the low-temperature caulyst "PERCA- 10 

DOX-16" pmvidea a gd lime of about 30 minutes at 

130degrees F, 7-1 minutes at 150 degrees Fund iboui 

2-3 minutes at 170 degrees F. The TRIGANOX-C' b 

a higher temperature catelysl thst does not rapidly decompose until about 250 degrees F. 15 

When tbe matrix formula of Example 3 is cast using 

thb caulyst system, the. following dau b obtained. 

Tcarpcntw* Hiting Bra ratio M0 degree* P. • . 

•rave cavfcy *"' 

fesotham tempera-are rite at cad 60 degrees F. 

of «MUS | ov a 

Uatwritrinkafcaf piled nitrix OT9 

Ju( prior to peeEns off piper 

carter end ihe avr. . 

The finbhed sheet fa observed to be smooth oo the 

bottom. 

Further experimenu are conducted to observe the 

changes ta shrinkage and the resulting product. The 30 

concentration of the "PERCADOX-16" fa varied in 

atept as shown in the following uble: 

14 

EXAMPLE 7 

In tht previous examples, the ambient temperature of 

the second cavity is set such that itt temperature is equd 

to the temperature of the sheet as it emerges from tbe 

second heating cavity. For example, if the energy output ofthe second heating cavity, plus the heal of reaction ofthe polymerization initiated fa the second cavity, 

causes the curing sheet to peek at 250* F, the g n temperature aad the walb of the second caviiy sro set at 

250* F. Widi lids eoadition, aad using the gd zone 

conditions ef Example 6, tbe cured sheet is essentially 

flat and free of significant stresses sfter coding. 

In example 7, the bottom base plate of the cure, oven 

is raised about 50* above the peak adiabatic tempenture 

of the sheet b thb condition, the cured sheet has a 

pronounced curl toward the upward fisee. Next, the 

bottom base plate of the cure oven fa lowered about SV 

bdow the peak adiabatic temperature. In thb condition, 

the cured sheet bu a pronounced curt toward the bottom face. 

The foregoing description ofa prefened embodiment 

alternate embodimeatt snd examples of the invention 

have been presented for purposes ef illustration and 

description. Tbe description b not bunded to be exhaustive or to limit the invention to the precise form 

disclosed. Obvlosdy, many modifications and variations are possible in light of tbe above teaching. The 

embodimems and examples presented above were 

chosen and described in order to best explain tlie principles of the invention and iu practicd application to 

thereby enable others skilled fa the an to bei utilize the 

TERCAD0X.14-.O. BASED 

ONUQLtDltEStN 

FRACTION OP MATRIX 

PERCENT ACTIVE OXYGEN 

OF CATALYST BASED ON 

UQUID KBSM FHACTJON 

OF MATMX 

SHRINKAGE 9 LINEAR 

DIMENSION. JUST 

MUORTOTHESAV 0ELTEMF.T. 

cuss 

aim 

aust 

otttt 

ao»« 

OOM 

OOM 

aosz 

aaosi 

moot! 

MOM 

OttOSI 

0.0020 

UD1? 

W»» 

unto 

ass 

atso 

e« 

030 

OLO 

OJ 

OtO 

Oil 

M 

I K 

I N 

ra 

in 

in 

m 

i» 

110 

119 

As the "PERCADOX-16" is reduced, it b necessary to 

mcrease the energy output of the first heating cavity to *° 

ensure that the matrix gela before emerging from the 

soaking oven. The following data is obtained using 

about 0i04% on the redn; 

55 

Tcapcraiwc eablni radio wave 

cwfcy 

Eulbcia tenpeiMWc rise at 

end of toaUag ovca 

Sheer ahrialiage of gdled auuli 

Just prior 10 pesSos off 

r carrier 

170 degrees P. 

120 degrees F. 

0 * 

CO 

The matrix emerging from the gd oven has a rubbery 

consistency and very lillle surface ripple. It b observed 

that the rubbery gelled matrix is free of significant 65 

shrinkage and tough enough to be peded from the carrying web snd cut into pieces before further curing and 

shrinkage. 

Invention in various embodiments and whh various 

modifications as are suited to the particular use contemplated. 

What fa claimed fa 

L.* A method of continuous casting of a polymerizable 

materid which shrinks upon curing, comprising the 

steps of: 

'(a) mixing said materid with a first catalyst group 

having a tower activation temperature sad a second catdyst group having a higher activation temperature to form a mixture; 

(b) depositing st least one liquid layer of sdd mixture 

oa aa entry end of an 

termined need to provide a moving layer of said 

mixture; 

(c) heating said moving mixture fa a firat region to a 

first temperature at least equd to uid lower activation temperature whereby sdd moving mixture 

partblly polymerizea to a first noa-Jiquid state 

. without excessive shrinkage; 

(d) providing conditions fbr sdd moving layer of sdd 

mixture to increase in temperature in a second 

tt 
rf?:VJA*'*#**?>-ti%, 10100. 1 U^-J-i • it4010V 

IB 

5,260,006 

16 

region lo a second temperature above said higher 

activation temperature whereby shrinkage occurs 

substantially uniformly in all directions in sdd mixture; and 

(e) Manipulating said layer of mid mixture to prevent 

dirinkage paralld to said web movement from 

transmission to the portion of said mixture resting 

en said web fa the vicinity of said first region, 

thereby preventing said shrinkage from damaging 

said materiaL 

2. Tbe method according to claim 1 further comprising the step of detaching mid non-liquid mixture from 

said web after said step of heating said mixture to a first 

temperature. 

2. The method according to chim 1 wherein add step 

or providing temperature increase conditions comprises 

the steps of heating to a second temperature above said 

higher activation temperature and holding said mixture 

at approximately said temperature until shrinkage b 

substantially complete. 

4. The method according to dshn 2 wherein ssid step 

or providing temperature increase conditions comprises 

the sups of besting to s second temperature above sdd 

higher activation temperature snd holding said mixture 

at approximately sdd temperamre until shrinkage is 

substantially complete. 

5. The method according to claims 1, 2, 2 or 4 

wherein said higher activation temperature fa ai least 10 

degrees fahrenheit greater than sdd lower activation 

temperature. 

«. The method according to claims L 2, 3 or 4 

wherein sdd step of providing temperature increase 

conditions comprises the steps of heating to a second 

temperature sbove ssid higher activation temperamre 33 

and holding said mixture al approximately ssid second 

temperature at least until shrinkage of said materid fa 

substantially complete. 

7. The method according to daim 4 wherein sdd 

second temperature is approximately the peak tempera- 40 

ture generated under adiabatic conditions by the polymerization reaction during said second heating. 

2. The methed according to daim 4 wherein the 

quantity of said first catdyst group b an amount suffident to polymerize said materid to a gd before h bas 45 

reached the location of sdd shrinkage transmission prevention step but leu than the amount which wifi produce excessive shrinkage before sdd location. 

10 

15 

20 

25 

30 

11. The method according to claim S wherein said 

second catolysl group has an activation temperature in 

the range of approximaidy 110 to 280 degrees F. 

12. The method according to claim 1 wherein said 

heating b applied subsuntidly uniformly throughout 

rhe cross-section of uid mixture whereby a substantially uniform temperature gradient Is mdnuined fa said 

mixture. 

13. The mediod according to efaim 12 wherein said 

heating comprises irradfating said mixture with radio 

frequency energy. 

14. Tbe method sccording to dsim 12 wherein said 

radio fluency energy fa projected fa a uniform pattern 

whereby energy concentrations are substantially dispersed. 

15. The methed aocording to daim 5 wherein said 

first caulyst group and said second catalyst group competit e same caulyst type and said first caulyst group 

further includes a promoter. 

16. An apparatus for oontfauous casting ofa polymerizahle materid which shrinks upon curing, comprising: 

(a) a mixer suitable to combine ssid materid wiA a 

first catdyst group having a lower activation temperature and a second catdyst group having a 

higher activation temperature; 

(b) a casting head adapted to deposit at least oae 

liquid layer of said mixture on aa entry end of an 

open web moving st a 'predetermined need to 

provide a moving layer of sdd mixture; 

(c) a heater suitable to beat laid moving mixture to a 

fint temperature at least equd to said lower activation temperature whereby said moving mixture 

polymerizes to a fint non-liquid Sttte without excessive shrinkage; 

(d) a dumber adapted to increase the temperature of 

said moving mixture to s second tempenture st 

least equd to sdd higher sctivstioa temperature 

whereby shrinkage occurs substantially uniformly 

in all directions ta said mixture; and 

(e) s mechanical isolator adapted to substantially 

prevent shrinkage paralld 10 said web movement 

from transmission to the mixture resting on the web 

in the vicinity of said first heater, thereby preventing ssid shrinkage from damaging sdd materid. 

17. An apparatus according to daim IC further comprising means for detaching add nonJiauld mixture 

from uid web after sdd heating of said mixture. 

is. An spparatus sccording to claim 14 wherein said 

f. The method according to daim I wherein sdd first heater comprises a means for irradiating said mixture 

catdyst group comprises, as a percent active oxygen of 50 with radio frequency energy, 

catdyst. about 0.0010*94 to about 0.02% .of the liquid IP. An apparatus according to daim It wherein said 

resin fraction of uid materiaL radio frequency energy b projected ta a uniform pattern 

10. Tbe method according to claim S wherein said whereby energy concentrations are substantially disfirst caulyst group has an activation temperature fa the persed. 

range of approximately IOO to 220 degrees fahrenhdt 55 • • • • • 

65 

iy 
OOV I OI-U J I I U IftlUV I OALC i • i-i4-o<J • iO-40 

_ _ P.15 

LOi 00*1V40* • n-ttLI vJU 

5,183,600 

1 3

 14 

(b) heating said mixture substantially uniformly (c) ineans for bolatmg shrinkage forces that occur in 

throughout iu cross section by radio frequency

 u* "Jj -

* rwiher^wnstream **»«* * beating 

v .. energy downturnTM of raid depositing step at least ^ J for'SdnuS Sd'S£ » thereafter fa 

to a temperature sufficient to mitute polymeriza- 5 mbstantld tbennd isolation such that substantially 

tion; adiabatic polymerisation and farther shrinkage 

• (c) providing conditions which isolate shrinksge occurs. 

forees'that occur is sdd mixture farther down- * *> •»«• » according to daim 4 wherein said 

stream from said heating point from transmhrioo .„ »* o frequency energy bprqiected in a unifompanera 

airam uv n MM owin g pownrwn umiwmww. w yfa^, ^^g y epoe^nifoas gre gShstsatiaDy 

upstream; and avoided, 

(d) nuintsinisg ssid isolated mixture during further 4. An apparatus for continuous casting ofa polymershrinkage in substantial ihermd isolation such that (cable materid which contains: a particulate filler aad 

polymerization occurs in a substantially adubatic whIA shrinb upon esBrinft comprising: 

L. M .,J«. M H^' M ,.^^U. 15 (a) a web baviMm upstream direction aad a downmaanCTandauppnr^byadnglebdt. stream dlre^aad^uitable to movant a predeterwhereby a sheet is provided free of substantid waip. . mined need; 

4. An apparatus for continuous casting ofa polymer- (b) B depositing member adjacent to said web adapted. 

izable materid which contains a particulate, filler and- • to deposit a controlled smount of a mixture eenwhich shrinks upoa curing, comprising: * ' ufafag said pblyiaerizabk materid ea sdd web; 

(a) means for depositing a controlled amount of s HV^*fo^i^*j^»?ld * * ",d 

atixure oohutaing sdd material on a web having (^T^kZ^dZ^D of sdd 

an upstream direction and a downstream direction heater ahd surrounding a portion of said mixture* 

aad moving st a predetermined speed to provide a 25 adapted ro maintain add mixture for a time free of 

moving mixture ef controlled thickness; substantid constraining forces and fa aubstantid 

(b) means fcr heating aaid mixture'substantially uni- . thermal fa°fatfan^^ • 

foraly throughout iu cross section by radio fie-' ..

lm

 ** •W^^M"TMo««««hB«fteiI>ercomprbiBnujr inaogawi » cn» www ^m w pp ^ t mechanied isolation device adapted lo prevent 

queney energy downstream of said depositing step M 9 ]ujn]Uge forca which devdop in said mixture downat least to a icmperature sufficient to Initiate poly- atream from add healer from transmission upstream, 

merizatioa; . a • • a a 

•a 

15 

45 

SO 

55 

SS 

IV