CA1078265A

CA1078265A - Solventless release coating

Info

Publication number: CA1078265A
Application number: CA242,332A
Authority: CA
Inventors: Richard E. Moeller
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1974-12-18
Filing date: 1975-12-18
Publication date: 1980-05-27
Also published as: BE836546A; FR2294765A1; GB1528788A; FR2294765B1; US4216252A; DE2556564A1; JPS5187182A

Abstract

ABSTRACT OF THE DISCLOSURE
.
A novel process is disclosed for the manufacture of a release "paper" which is based on the application of a fluid silicone composition to a paper substrate. The silicone fluid is directly applied without any solvent and without emulsification. The application technique is based on the use of a two-roll offset gravure coating apparatus wherein the substrate to be coated is run at a higher speed than the gravure roll.

Description

~078Z65 Thi~ invention proviaes a nov-l ~ethod for the production of a reloase "paper~ whieh i8 based on the application of a fluid i1ieono eo~po-ition to a sub-trato - without any ~olv-nt ~nd without e~uls$fication of the ilicon- fluid Pr--~ure en-itive adhe~ive~ are widely e~ployed on tape~, label-, carpet til 8 and ~any other rticle-co~only ~ploy d in th ho~e, offic-~ and factori-- On Dany of the-- article~ the adhe~ive ~urfac- i- protected by a relea~- ~papor" which ~ay be a~ily pe-led off i_ o~iately pr~orrto u~e ; It ~hould be undor-tood that a- u~ed herein, the t r~ r-l a-- ~pap~r~ i~ u--d to include not only paper but al-o oth r protective ub-trate~ uch a~ ~ynthetic filas, e.g poly thyl n-, pve, polye~t-r, te whieh requir- relea~e prop rtio~ wben o~ploy d ~ a prot-ctive baeking on adhesive surfac-s Al~o, it i8 po -ible to coat the adho~ive directly ov~r the cur-d ~olventler~ ~ilicona composition and thoroaft r e~ploy a transf-r eoating techniqu- to place that adhe~ive again~t the appropriate fac- ~tock ~urface The releaJe ~paper-~ of the prior art have b en eoated with s$1ioone co~po-ition- th~t have been applied in a olvent or e~ul~ion type of dispersion This coating ~othod has reqyired ~ eurLng cycle which would effect r-~oval of any ~olvont or extr~n~ou~ l$guid that wa~ pr~sent in the ilicon containing di~persion She pre~nce of these oxtraneou~ liquid- re~uired highar energy cost~ for drying and ~lso pollution proble~ were cau~ed by th need to vent the ~olvent Also, if tho solvent wa~ coll-ct-d ~nd recycled, thi~ further add d to the C08t. Recently, olv~nts have been in short supply and this has al~o contributed to pr~duction 5. proi~ r _ I

Thor-fore, a n ed ha- xi-ted for a proc-o~ that could ffici-ntly produce a r-l-as- ~pap r~ without the u~e of a ~olv-nt On- probl ~ ncounter-d in th dir-ct application of oQlYent-fr-e Jilico~e fluid i~ th- difficulty in co~trolling th amount of ~ilicon- fluid that i~ applied to th- ~paper~ ub tr~t ~o that a ~ini~u~ ff-ctive a~ount of ~ilicon ~ay be applied Shi- ~ini u~ amount io ioport nt for ~ -proaucing an ~cc ptablo r-l a e ~p~per~ at econo~ic pplication rat ~
Conventional offo-t gravur- co ting t chniqueo have not bee~ ati-factory for thi~ purpos- a- th application l v-l- hav b n too high to b- cc-pt bl- It has b -~
di~cov red that th application l v l ~ay b reaucea to acc ptable l-v-l~ if th oub-trat-- i- run through th- gravure coat~ng app ratur at a lin ar p- d that $o greater than the ..........
linear .p-.a of th gravure roll Accordingly, it i~ a pri~ary ob~-ct of this inv ntion to providb a ~ethod of manufacturing a r-lease ~paper~ which i- carried out without th aid of a solvent or ~uls~fied -~
y-te-It i8 al80 an ob~ect of thi~ invontion to provide a method for coating a substrate with a ~ini~u~ ffectiv~ ~ount of a ilicone co~position It i- al80 ~n ob~ect of thi- invention to provide a method of ~king a r~leaoe "paper~ with a ~inimu~ u~e of n-rgy and a ~ini~u~ ~ount of pollution of the environ~ent ~h~ inv ntion provlde- a ~novel ~ethod of coating ub-trate with a ~inor a~ount of a ~ilicon~ coDpooition The ~ilicone co~pooition consi-t~ e-s-ntially of (a) a vinyl chain-~topped polysiloxane having the foraulat

- 2 -i 107826S 8S~-1543 R2 f~ 2 ~ a2 CE12 ~ s1~8107 s! ~ a CE~2 wh r-in R a~d Rl r- ~onovalent hydrocarbon radical~ fr-o of aliphatic un~aturation with at lea-t 50 ~ole p rcent of th R nd R group~ b-ing ~ethyl nd n has a valuo ~uffici-nt to provido a fluid ~at rial having a vi~co~ity of fro~ 200-5000 oentipoiJe~ at 25C , pref rably 300-400 cp-~
(b) a platinu~ cataiy ts ~ c) an a~ount of a liquid organohydrogenpoly~iloxanehavi~g th for~ulat (R )a (~)b ~iO ~ a-b ufficie~t to provid fro~ about 0 5 to about 1 0 ~ilicone-bonded hydro~e~ ato~s p r Jilicono-bond d vinyl group in the c qpo~ition, ~h r-ln R i~ a d fi~ed above, a is fro~ 1.00 to 2.10, b i- froa about 0.1 to 1 0 a~d tho u~ of a plu- b is .
froo ~bout 2 00 to 2~67~ th re being at lea~t 2 ilicone bonde~
,.j .
hydrogen ato~ p r ~ol culeJ ~id ~ethod co~pri~ing applying aid ~il$eon co~po~$t$on to a aubstrat~ with a two roll off-et gravure coating ~achin wherein the sub~trate i8 run at a higher pe-d th n th- gravure roll Th ~ub~trat- that 18 coated ~ay bo a prot-ctivo ~ub~trate that is ~ade of paper or ~ynth tic fil~s The cured ~ilicon coat d Jurface ~ay be la~inated to~ an appropriat- face ~tock ~ubstrate that ha~ b~en coat~d with . .
adh -ive or alternatively, the adhe~ive ~ay be coa~ed over tho cured silicone coated urface and th~ la~inated to appropriate fac- ~tock ubstrato Thi~ result~ in the tran~fer of the adhe~ive to th~ fac- stock sub~trate As used herein tho ten~ ~novalent hydrocarl~on radicals free of aliphatic unsaturation i8 u~ed to include alkyl radical~, e g , methyl, ethyl, propyl, butyl, octyl, etc

- 3 -. . , ~` 1078265 radicals aryl radicals, e.g , phenyl, tolyl, xylyl, otc radieal~ cycloalkyl radical~, e.g , cycloh~xyl, cycloheptyl, ; etc ra~ical~, In the preferr-d e~bodi~ent~ of the i~vention R and ~ will be ol ct d fron phenyl and ~thyl radical~
with the e~p-cially pref-rred o~bodi~ent~ being all ~ethyl ~ h~ a~ount of ilicone co~po~ition that i8 applied to the paper substrate should be between about 0.1 and 4 0 ; Ib- per 3000 ft or ~ore prof rably between 0.1 a~d 2 0 lb~ per 3000 ft. The euring operation ~hould be carried out in an oven at a t-~perature of fro4 150-650 F to cure the ~ilicone co~po~itio~.
Tho orga~ohydrog~npoly~iloxane ~ay be linear, cyclic or re~inou- in ~aturo, but preferably i~ ear or re~inou~
One illu~trati~e nat rial i- a lin- r d~ethyl hydrog n chain-~topped di~othylpoly-iloxane ~at~rial containing fro~ 2 to 3 ~ilieon atou- in the ~ol cule. A further ~peeific eo~pound ~ay be a r~ ou~ eopoly~r of di~ethylJiloxane unit~, ~ethyl-hydrogen-siloxa~e unit- and tri~ thyl~iloxan UDit- whieh contain fro~ ~ ~to S or 10 or ~ore ~ilicon ato-- p~r ~olecule Al~o illu-trativ are 1,3,5,7-tetra~ thylcyclot-tra-iloxan s a eopolyaer ¢on~-ining three di~ethylhydrog n ~iloxane unitJ
~nd one ~onon thyl-iloxan unit p r ~ol cul s ~d ~ low vi~co-ity flu~d co~po-ed of di~ethylhydrog-A silox~no units and SiO2 ua~t~ in th- ratio of 2 ~ole~ of th for~ r to 1 Dole of the l-tt r E-pecially w ful i~ a lin-ar ~ethylhydrogen-poly~lox4n flu d or re-inous DethyLhydrog npolysilo~an .
~uch conpon nt~ are w~ o~n to those J~illed in thi~ art and aro de~cribed in U S. P~tent 3,436,366, April 1, 1969 Al80, U S Pat-nt 2,491,843 d - crib B A UBOfUl fa~ily of liaoar tri~ethyl~ilyl chainstopped poly~ilox~no- One i8 ~ade by cobydrolysing 5 parts of (C~3)3- SiCl ~nd g5 p~rts of C83~iC12 ~isco~ity 100 cp~ at 25C The ~i~cosity of .. . ~ ' ~(~78Z65 th organohydrog npoly~iloxane~ ~ay be v ried bst~-n 10 ana 10,000 cp~. Sho pr-ferred range i~ between SOO and SOOO
cp~.
An ~ ntial featur- of th inv-ntion r-l~t 8 to th fact that th- pap r ~u~t b- run at a higher p~ d than th gravur- roll The applicatlon roll ~ay be run at th- ~ a ~p- d a- the gravure roll or it ~ay b- run ~t tho ~e ~p--d a- th paper ~h for~er ~ thod r--ult~ in a ~wiping~ action of th pap r on th- applic~tor roll whil- th latt r ~ethod le r--ult~ in a wipi~g actlon betwo~ th~ applicator roll and .
th- gravur- roll Sh- off-ct of the ~iping~ actlon i~ to lower th- qua~tity of ~licon ¢o-poJition depoDition r~te on the fini hed prod~ct Th ratio of th gra~ur- roll l~n ar ~elocity to the lin~ .p~ a Jhould b- b-twe-n 0.1 and 0 9 Tho coaponent~ of the ~inyl chain-~topp-d poly-iloxano ar- ~ 11 k~ow~ in the art and are do~crlb d in U.S Pat nt 3,436,366 ~h ~particul~r vinyl cha~n--topped poly-iloxan~
~ploy d in thi~ inv-ntion h~v a lo~ r vi-co-ity than th aat rial- di~clo-ed in tho afo¢~ention~d Pato~t a4d ~re r-adily propar-d by thoa- ~kill d in the art. ~he liquid organdhydrogenpoly~ilox*ne~ are al~o dbscrib-d i~ U S 3,436,366.
A- a platinu~ cataly~t, the chloropl~tinic acld co~pound~ of 8peier, U.S 2,823,218,o~n b us-d, g , as olution~ in alcohols, water, glycol~ e~t rs, particul~rly i-opropanol ~n~ th d~ thyleth~r of diethyl-n glycol Al-o uitabl are the platinu~ hydrocarbon cqplexo- of ~y, U.S. Pat nt 3,159,601, whlch are of the g ner~l for~ul~
~Pt C12.olefin) 2 and ~1 (Pt C13.ol-fln) ~ n the ol f~8 ar-alk n 8 of 2 to 8 carbon ato~, cyclo-lkene~ of 5 to 6 carbon ata~, tyr~o, and the like. The-e ca~plexes aro for~ed, e.g., b~ re~cti~g chloroplatinic acla with olefin, o.g., ethylene, ~d they are soluble in hydrocarbon solvent~, e ~ , , ' " ' .

~078Z65 benzene, tolu-ne, mineral ~piritJ, or oxygenated solvents, ~uch a~dLoxane, tetrahydrofuran, and the like Also sui Wble a~ platinu barrier compound~ are the plat$nu~ cyclopropane coqplexe- of Ashby, U S 3,159,662, i~ued Dece~ber 1, 1964, of th gen ral fon~ula (Pt C12 C3H6)2 Tho~e aro ~ade, for ex~plo, by tr-ating tPt C12 C2H4)2 (de~cribed in U~S Patent 3,159,601, dat d Dece~ber 1, 1964) with cyclopropan~ in chlorofor~ and glacial acetic acid, and they are solubl in hydrocarbo~ ~olv-nta, g , benzen-, tolueno, xyl no, ~in-ral ~pirit~, al~ohol~ or ether-, uch a~ octanol or tetr-hydrofur-n Purth~r illu~trativ of suitablQ platinw~ co~pounds are the platinu~ alcoholat- (ethorato, carbonyl) co~pl-xes of L~oureaux, U S P~tent 3,220,972, dated ~ov~Dber 30, 1965 ~he~e are for~ed by reacting chloroplatinic acid with a high r alcohol, g octanol, or an aldehyde, e g , octyl ; aldehyde, or an th r alcohol, g , ~onoethyl eth-r of dl-thyl ne glycol, at 70-75C under a vacuu~ for about , .~
16 hour~
Another fa~ily of platinu~ co~poundb co~prises the platinu~-vinyl ~iloxane co~plexe~ disclosed in K~rstedt, ., .
U S Pat-nt 3,715,334, dated February 6, 1973, and U S
Pat nt 3,775,452, dat-d ~ove~ber 27, 1973, both of which aro a~igned to the a~ignee of the pr-s nt invention Thoy are madb by effocting a reaction betweon a platinu~ halide and an un~aturated 8iloxano, e.g. 1,3-divinyltetra~ethyl disiloxan~, ~nd re~oving availa~lo inorganic halogen fro~ the re~ulting reaction product Bspecially suitable i~ ~ platinum c qpl-x of tetramethyldivinyl diAoloxane which c~n bo ^ prop~red by adding 25 part- of NaHC03 to a ~ixtur~ of 25 parts - 30 o ~odiu~ chloroplatinite, 50 parts of 1,3-divinyltetra-methyldi~iloxane und 125 parts o~ ethyl alcohol, heating for 15 ~inutes at 70-75& thea filteriag, washi~g and stripping ~ .

~he re-idue i8 a pl-tinu~-divi~yltetra~othyldi-iloxane, ub-tantially fr~e of ch-~ic~lly co~bin-d chlorine. It i~
~olubl in ~any inert organic ~olvent~, e.g hydrocarbon~
such a- b nz~ne, tolu-n , xylen , heptan , ~ineral ~pirits, alcohol-, ther- and the like, such a- ethanol, pentanol, t trahydrofuran, d~oxane, etc.
With re-p ct to all of the plati~u~ co~pounds, a uit-able concentratlon of the co~pound in the olv nt will -provid ~ro~ O.~X by weight to 20% or higher by weight a~-ayed a~ platinu~ ~ tal. Pref rably, however, concentrationJ
a--aying a~ platinu~ ~ tal in th rang~ of 0.1 to lg% by weight ay b- u--~. A -olution of th c qpound i~ a hydrocarbon ~olvent, .g , tolu n-, a~-aying for 1~ plati~u~ ~etal, i~
e~p-cially conv niont.
Al~o a t-traalkyl titanate ~ay be added to the ilicone co~po~ition to i~prov- adhe~ion. Gen rally fro~
l-~X, pr-ferably 3% oftetrabutyl titanate may bo ~ploy d.
~o~ev r, th inclu~ion of th tetraalkyl titanat~ h~ a t-~d ncy to r-tard the curo and the curing t~peratur- ~ay ~i 20 hav to b- rai--d to incr-a-- tho r-to of cure.
i A cur- inhibitor such a~ Yinyl acet~te i~ o ploy d at a level of 400 pp~ to prev~nt pre~ature (i.e roo~
te~poratur-)curing of the silicone co~po-ition and provide ext-nded bath lif-. If the inhibitor is not prosent the caqpo8ition will rapidly cure and beco~e unu~eable Oth-r cur- inhibitor~ which ~ay be eqp~oyed include tho--d~clo~ed in the Chalk U.S. Patents 3,188,299 dated June 8, 1965; and 3,188,300, dat d June 8, 1965: and U S 3,344,111, datod Sept~mber 26, 1967. Al~o alkenyl wbstituted i~ocyanurate~ such a~ triallylisacy~nurate, ethylacetoacetate, ~,N-dLmethyl~or~amidb ox ~-ally~ethylcarbon-t- ~Q b u8-d ~ cur- inhibltor-. Th- ilicon- co po~Ltio~-.
~, ~ 1078Z65 usod in the pra¢tice of thi~ invention ~ay be prepared with 80-100 parts by weight of th~ vinyl chain-Jtopped polyJilox~ne and S-lS part- by~eight of the organohydrogenpolysiloxano A tw~ roll off~-t gra~ure coat~ng apparatu~ i8 u~-d in tbe application of the ~ cone co~po~itions~ In ; thi~ appa~atu~, the gravure roll and tho rubber roll are in the 8 _ horizontal plan The gravure roll pick~ up the ~ilicono fro~ the bath and exc--~ fluid i~ re~oved by th doctor blade She fluid in the gravuro cell~ i~ th-n tran-forred fro~ th~ c ll~ to the rubber roll Tho fluid on tho rubber roll is then split, with approxi~ately 50X of it b ing transferr-d to the paper and tbo oth balf ro~aining ; on th- rubb r roll Gravure roll- having 140-340 guadrangular c-ll- p r linear inch ~ay be us-d The u~ of roll~ with fin r line ~pacing~ will re~ult in lowor ~uantities of ilicone ¢oqpo~ition being depo it-d on the r-loa~e paper In on te~t, a coating achino ~anufactured by ~orldwide Converting ~achin-ry wa us-d with a 180 line . .
quadrungular roll with a cell depth of 0 0018 inch The curing ov n wa~ 25 ~ et along with two 12 5 foot zones In th$~ coating head, th line ~peed ~oula be op~ratod indbpendbntly of the coat$ng hoad speed For exaqple, while the coating head speea would be h ld con~tant at 11 ft /~in , the line ~p ed ¢ould be incr-~sed fro~ 11 ft /~in to a~
h$gh a- 100 ft /~in So ~alntain ~ooth oporation, the teol backup roll is run at lino spe d, while the gravur- roll and rubber ~pplicator roll wer- held con~tunt Since thi~
results in a wiping action of the w~b over the applicator roll, a ~ini~u~ a~ount of pres~ure i~ applied by the backup .
roll again~t the paper and th applicator roll Two different papers were coat-*~during the te~ts ~o~t of th~ ~oati~g wa~ done Oh a 42# ~-mibleached Plai~wel ~ , but a 50#
; Ugla~ine like~ Deerfield ~ was also u~ed The felt side was . . .
coated in all ca~e~

.. . .
.. . : .
.. ~ .

88I-15~3 $he ~ilicone co~po~ition co~pri~es 100 part~ by weight of a ~inyl chain--topped polyorgano-ilox n having a visco~ity of 300-400 c-ntipoi-- at 25 C , 10 part- by ~eight of a ethyl hydrog n poly~iloxane containing ¢o~po ition having a vi-co-ity of about 700 c ntipoi--~, a plstinu~ cataly-t a~ prop~r-d in th above ref r~oed L~or-aux patent and a vinyl ac-tat~ inhibitor A~ ~ntioned abov~, th gravurc roll e~ploy d was a 180 lino quadrangul r roll S~nc- th- theoretical dir-ct d po-ition wa~ 4 65 lb~ /re~a (3000 ft 2), the theor-tical d po-ition for a two roll off-et coating co~figuration (on fil~ plit) ~ould b approxi~at ly 2 3 lb~ /r-a~ $hi~
a--u~e~ that th coating head and th w~b ar- ~ynchronized How-v r, i the ~pe d o th w~b i~ incr-ased relativo to th coating beaa (or the ~p- d of th co~ting head rotard d r-lativ to th ~eb p~ d), the a~ount of fluid available to uny ~iv n ~rea of the w~b i- decrea--d Con~equently, the ~llor thi- ratio beco~e~, th lo~r the depo ition on the ~b.
T~bl~ I contain~ a s~ri~- of th~or-tical calculation~
to ~how the diff r-nt depo ition- that could be expected - d pe~ding on the ~el-ctio~ of tho gravur- roll ~h-calculatlon- are ba--d on the as-u ption that tho ~e fil~
plit- and wipi~g actlon~ whi¢h ~re ob~ rved during t}~i8 trial are indop~aent of the ~hoico of gravuro roll. For ex~ple, during the trial a h~ad to line ratio of 0 35 gav a dopo~itioll of 1 45 Lb~./rea~ ~ich i8 31X of the theoretical direct depo~ition Consoqu-Atly, a 200 line quad roll, op-rating in the sa~e ~er, should give a d6po~ition of 0.69 lbs /re~ ~31X of the th-oretical direct depo~ition for that roll) _ g _ -iO7B265 TABLE I

Th-or-tical Calculatod DepoJition- at Different aravur- Dir~ct He~d/lino R~tio~ (lb- /rea~) Roll DePo-ition 1 0 0 58 0 48 0 35 0.11 190 line 2 76 1 38 1 17 0 98 0 73 0 53 guad 200 line 2 21 1 11 0 85 0 79 0 69 0 43 gua~
120 lin 2.12 1.06 0 90 0 76 0 66 0 41 pyru~id 140 lino 1.61 0.81 0.68 0 58 O SO 0 31 pyr~d 165 lin 1 10 0 55 0 47 0 39 0 33 0 21 pyra~id A nu~b r of run- ~ere aad u~ing the sa~e 180 line quadrangular roll r. On run W~J ~adb uJing ~ technigue whor-in th pap r web pa --d over th teol backup roll to apply a ,, ~ki~- coat- T~o control run- wero al~o ~ad u~ing the ~me ilicono for~ulation in olv-nt baJoa y-t- ~ at 10 and 50X
~olid~ Tho r-~ult~ are ~-t forth ~n Tabl IIs , TABL~ II
Co~ting Lin Spood HeadJ Ovons Te-t Sub-tr~to T-chnioue ~Ft/~in) Lino (OF~ Cur-1 Plain~ ll Xi-~ Coat 43 0.58 450/400 OK
2 Plain~ell Off~et 43 0 58 450/77 OK
Gravur~
3 Plainwoll Off~ot 80 0.48 450/550 OK
~ravure

4 Plain~ ll Off--t 25 0 35 500/77 OK
Gravure Plainwell Offs~t 25 0 11 500/77 OK
Gravure 6 De~rfield Off~et 50 0.48 350/350 OK
Gravuro 7~ Plainwell Off~ot 150 0 35 500/500 OK
Gravure 8~ Plainw~112 Offset 30 0.35 500/500 OK
Gravur~
10% ~eptano 250% ~epta~e Control , ~ 8SI-1543 TA~LE II (Conti~u2d) ~e~t DoDo~ition tlb~ /re-n) 7~ 1 16 8~ 0 43 Tho cur- profile of a ~ilicone composltion _ loying 3 parts by weight t-trabutyl titanata wa~ inv-~ti~at-d u~ing cure ti~es fro~ 50 ~oconds at 350F to 3 7 second~ at 625 F The re~ult- are ~how~ on ~abl IIIs ," ' TA~

~e~t Oven $e~porature Line Speed Dwell T~se (F~ Zonel~Zone 2 (Pt ~Min ~ Cure ~SecondbL
'~ ' S~e~r 37 5 S~r 30 ~~= 60 8~ear 25 ;~ 10 400/400 50 OR 30 Sm ar 25 11 450/S00 300 ~ r 5 13* 500/50C~ o S~ ar 10 5 14 600/600 200 O~ 7 5 350 S~oa~ 4 3 450 S~ear 3 3 . -* Control run with l~X add~d hepta~e ,''' , .
. , :

107BZ~;5 Anothor eries of te~ts were rw~ on a two roll offsot gravure coating apparatus ~orein the gravur- roll and the pplicator roll wer- arr nged in a vertical plane In these t -t-, th gravure roll was run at a lower linoar velocity than the applicator roll and con~eguently th- wiping action o~:curred in th~ nip b t~-n the~e t~o roll-. Thu-, the backup roll, - the pap r w b and the applicator roll were run at one speed, whil- the gravuro roll operated at a lower ~p-ed. Sh oven u~-d with th off-et gravure coating head was a v rtical 45 foet (total length) dryer It con-i~t d of two 22 5 feet zone~, with ach zono capable of a maxil ul~ te~per~ture of 400 F
Th- ~ilicone c~po-itions contained 100 parts by weight of a vinyl chain-~topp d polyorganosiloxane having a viscoJity of 300-400 cl~ at 25C, 10 part~ by weight o~ a ~thyl hydrogen poly-iloxaDe fluid having a vi~co ity of 700 c-ntip~e, 400 pp~ of vinyl acet~te as a curo inhibitor, a platinu~
cataly~t and ~h re indicat d 3 part~ by weight of te~trabutyl-tita~ate.
Sh gravur- roll was a 180 line gu~dr~gular roll (i e 180 quadrangular c-~118 per liJ~ear inch) A nu~r of t-~t~ wer~ carried out u~ing the above-de~cri2~d ca~position Tl~ off~et gravure coating apparatus w~- operated ~ith the gravure roller nd applicator roller arrang d in a vertical plano $he deposition ~tudies were carriea out by infra red ~pectroscopy and by foil deposition ~easur_nts $h~ sub~trate~ wer- cured at 350F $he following substrate~ were evaluat-ds A - W y rhaeu~er Supercalendered Xraft B - ~ & 0 Clay Coat Paper C - Polyestor f ill-Tho re~ults of t~el~e te8t8 aro ~u~arized in Tablo IV
i `:
'' '. ~ ' :

8sI-l543 ~CD'78Z65 TAB~e IV

I.ine Speed Hoad/ Depo~ition (IR) Te~t Curoft./~in. LilleSubstrate lb~./ream 16* OK~ 20 1~ 0 A 2.19 17 OX 20 O. 50 A 1.00 18 OK 20 O. 25 A 0. 69 19* OK 20 1. 0 B -------OX 20 O. 50 B ------21 OX 20 O. 25 B ----2222 OK 80 0.125 B ____ 23 OK 60 0 .167 B ~
24 OK 40 1. 0 A --------OR 50 O. 5 A ------26 OK 50 0.25 C ----27 OK 100 1. 0 A -------28 OK 200 1. 0 A -----29 OK 300 1. 0 A ----oXl 50 O. 25 B ____ Test Depo~ition.]b~.~roalo 16~ 1. 75 17 0.~3 18 3.52 19~ 1. 60 -:
1. 22 21 0.70 222 *Control 23 ---- 1-3% tetrabu~yl titanate 24 1 72 2 - could not obtain a uniform 1 13 3 - c!o ting b~th consi~t~d of 100 26 0.65 pa~t~ by woight o~ ~ vinyl chain-27 ____ stopped polyorg~nosiloxallo wi~h a vi-co~ity of 3700 cps, 5 palrts 28 ____ by wa$ght of a ~otffll l~yd~ogen 29 ____ contai~ing poly3110x~n~ with a 0 61 vi~:o~ity of 700 ~p~, and 3 p~rts by w~ight of te~rabutyl titanate.

-- 13 -- , . .

89I-lS43 ~078265 TABLE lV (Continu d) L~ne Spe--d H~ad/ D~po~ition (IR) T--t Cur- ft./~in. in~ Sub~trate lb~./ro~ -31 OR 20 0.18 A 0.47 32 OX 20 0.18 A 0.49 ~t De~o-ition lb~rea~

32 ___ ; The rel-aso prop~rtie~ of ~everal of th r~lea~e pap~r~
w~re v~luat d. The test nu~b-r~ which correspond to th~ te~t ; nu ber of ~ble III indicate that the te~t-d r~lease paper i~
the id ntical pap~r. A Gelva 263 acrylic adh~sive ~as applied to the ~ilicone coated paper at a thicknes- of 7.5 ~il8 ~wet).
After the adh~4iv~ wa~ properly dried, the sh~et- wsre la~inated to supercalendared kraft fac stock. ~h~ la~inato~
~r- cut into 2 ~nch x 9 inch ~trip~ and ag~d for various ti~-~at 770F. and 140F. befor~ relea~e value~ w~r~ det-r~in~d.
R~l aso wa~ aea~ured in gms./2 inch ~t 400 in./~in. ~h~ ro~ult~
' are ~u_ ariz-d in ~able V~
' ~ABIæ V
tion A~qed_t 77F. A~ed at 140F.
T~t ~/rea~ ~ 1 WeQk 3 We~k~ ~ e~ k 7 ~
- 17 1.00 65 125-160 16050-75 150-200 120 18 0.69 100-125 7500 400-500100-125 150-175 140-160 21 0.70 tear tear ---- t~ar te~r ----- 31 0.47 ---- 150-160 90 ---- 75 100-120 3~ 0.49 --- 200-350 150-250 ~ 350-45~ 250-300 `:
1 deter~ined by IR
2 dGtQr~in~d by ~lw~inu~ goil Obviou~ly, oth~r modific~tion~ and variations of the pros~t inventi~n ~ro po~ible in th~ light of th~ ab3v~ toaching.
It is ~her~f~r~ to b~ und~r~tood that chang~ ~ay b~ ~ade in thR
particular e~bod~t~ o~ the inv~ntion de8~ribed which are with-in the full int~nded cope o~ th~ invention a~ defin~d by the ; app~ndod cl2~m8. - 14 -.

Claims

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A method for coating a substrate with a minor amount of a solvent free silicone composition which consists essentially of:
(a) a vinyl chain-stopped polysiloxane having the formula:

wherein R and R1 are monovalent hydrocarbon radicals free of aliphatic unsaturation with at least 50 mole percent of the R and R1 groups being methyl and n has a value sufficient to provide a fluid material having a viscosity of from 200 - 5000 centipoises at 25°C.;
(b) a platinum catalyst;
(c) an amount of a liquid organohydrogenpolysiloxane having the formula:

sufficient to provide from about 0.5 to 1.0 silicon-bonded hydrogen atoms per silicon-bonded vinyl group in the composition, wherein R is as defined above, a is from 1.00 to 2.10, b is from about 0.1 to 1.0 and the sum of a plus b is from about 2.00 to 2.67, there being at least 2 silicon bonded hydrogen atoms per molecule;
said method comprising applying said silicone composition to a substrate with a two roll offset gravure coating machine having an applicator roll and a gravure roll, wherein the substrate is run at a higher speed that the gravure roll, and thereafter heating the coated substrate to cure said silicone composition.

2. The method of claim 1 wherein the substrate is run at a higher speed than the applicator roll.

3. The method of claim 1 wherein the substrate is run at the same speed as the applicator roll.

4. The method of claim 1 wherein the ratio of the gravure roll linear velocity to the line speed is between 0.9 and 0.1.

5. The method of claim 1 wherein less than 2.0 lbs.
of silicone composition is applied per 3000 square feet of paper substrate.

6. The method of claim 1 wherein the coated substrate is heated in an oven at a temperature of 150-650°F. to cure said silicone composition.

7. The method of claim 1 wherein said silicone composition contains 100 parts by weight of a vinyl chain-stopped dimethypolysiloxane having a viscosity of 200-5000 centipoises at 25°.; 10 parts by weight of a methylhydrogen polyorgano-siloxane having a viscosity of 10-10,000 centiposes.

8. The method of claim 1 wherein said composition contains 100 parts by weight of vinyl stopped dimethylpoly-siloxane silicone fluid having a viscosity of 200-5000 centipoises at 25°C.; 5 parts by weight of a vinyl chain-stopped dimethyl-polysiloxane fluid having a viscosity of 200-5000 centipoises and 5 parts by weight of a methylhydrogen polyorganosiloxane having a viscosity of 10-10,000 centipoises.

9. The method of claim 8 wherein said composition includes a minor amount of an adhesion promoter.

10. The method of claim 9 wherein said adhesion promoter is tetrabutyl titanate.

11. A method for coating a paper substrate with a minor amount of a solvent free silicone composition which consists essentially of:
(a) a vinyl chain-stopped polysiloxane having the formula:

wherein R and R1 are monovalent hydrocarbon radicals free of aliphatic unsaturation with at least 50 mole percent of the R
and R1 groups being methyl and n has a value sufficient to provide a fluid material having a viscosity of from 200-5000 centipoises at 25°C.;
(b) a platinum catalyst;
(c) an amount of a liquid organohydrogenpolysiloxane having the formula:

sufficient to provide from about 0.5 to 1.0 silicon bonded hydrogen atoms per silicon bonded vinyl group in the composition, wherein R is as defined above, a is from 1.00 to 2.10, b is from about 0.1 to 1.0 and the sum of a plus b is from about 2.00 to 2.67, there being at least 2 silicon bonded hydrogen atoms per molecule; said method comprising applying said silicon composition to a paper substrate with a two roll offset gravure coating apparatus wherein the gravure roll and the applicator roll are in the same horizontal plane and the paper is run at a higher speed than the gravure roll and thereafter heating the coated paper to cure said silicone composition.

12. A method for coating a paper substrate with a minor amount of a solvent free silicone composition which consists essentially of:

(a) a vinyl chain-stopped polysiloxane having the formula:

wherein R and R1 are monovalent hydrocarbon radicals free of aliphatic unsaturation with at least 50 mole percent of the R
and R1 groups being methyl and n has a value sufficient to provide a fluid material having a viscosity of from 200-5000 centipoises at 25°C.;
(b) a platinum catalyst;
(c) an amount of a liquid organohydrogenpolysiloxane having the formula:

sufficient to provide from about 0.5 to 1.0 silicon-bonded hydrogen atoms per silicon-bonded vinyl group in the composition, wherein R is as defined above, a is from 1.00 to 2.10, b is from about 0.1 to 1.0 and the sum of a plus b is from about 2.00 to 2.67, there being at least 2 silicon bonded hydrogen atoms per molecule;

said method comprising applying said silicone composition to a paper substrate with a two roll offset gravure coating apparatus wherein the gravure roll and the applicator roll are in the same vertical plane and the paper is run at a higher speed than thegravure roll and thereafter heating the coating paper to cure said silicone composition.

13. The method of claim 12 wherein the paper web is contacted with a steel roller that contacts the rubber applicator roller.

14. The method of claim 1 wherein the vinyl chain stopped polysiloxane has a viscosity of from 300-400 centipoises.

15. The method of claim 1 wherein a cure inhibitor is employed in said solvent free composition.

16. The method of claim 15 wherein vinyl acetate is employed as the cure inhibitor.

17. A method for coating a substrate with from 0.1 to 2.0 lbs. per 3000 ft2 of a solvent free silicone composition which consists essentially of:
(a) a vinyl chain-stopped polysiloxane having the formula:

wherein R and R1 are monovalent hydrocarbon radicals free of aliphatic unsaturation with at least 50 mole percent of the R
and R1 groups being methyl and n has a value sufficient to provide a fluid material having a viscosity of from 200-5000 centipoises at 25°C.;
(b) a platinum catalyst;
(c) an amount of a liquid organohydrogenopolysiloxane having the formula:

sufficient to provide from about 0.5 to 1.0 silicon-bonded hydrogen atoms per silicon-bonded vinyl groups in the composition, wherein R is as defined above, a is from 1.00 to 2.10, b is from about 0.1 to 1.0 and the sum of a plus b is from 2.00 to 2.67, there being at least 2 silicon-bonded hydrogen atoms per molecule; and (d) a cure inhibitor which prevents premature curing of the silicone composition; said method comprising applying said silicone composition to a substrate with a two roll offset gravure coating machine having an applicator roll and a gravure roll, wherein the applicator roll is run at the same speed and in the same direction as the substrate and ratio of the gravure roll linear velocity to the substrate speed is between 0.1 and 0.9, and thereafter heating the coated substrate to cure said silicone composition.

18. The method of claim 17 wherein said substrate is paper.