CA1196747A - Ultraviolet light curable acrylic functional silicone compositions - Google Patents

Abstract

ULTRAVIOLET LIGHT CURABLE ACRYLIC
FUNCTIONAL SILICONE COMPOSITIONS
Abstract of the Disclosure Acrylic functional siloxane polymer compositions which are especially useful for ultravoilet curable silicone release coating applications are provided as a reaction product of omega-chloro-l-alkens, dialkylhydrogen chainstopped polydialkylalkylhydrogen siloxane copolymers, catalytic amounts of precious metal complexes and acrylic functional monomers.

Description

;7~L'7 ULTRAVIOLET I,IG~T CURABLE ACRYLIC
FUNCTIONAL SILICONE COMPOSITIONS
Field of the Invention The present invention is related to acrylic functional silicones and polyorganosiloxane copolymeric compositions which are curable or crosslinkable upon exposure to ultraviolet light or radiation, and which are particularly useful in silicone based release coating applications.
Background of the Invention Silicone release compositions, and especially paper release compositions, are widely used as coatings which release pressure-sensitive adhesives for labels, transfer tapes, decorative 1~m; n~tesl and the like. Such silicone products are most commonly sold as dispersions of reactive high molecular weight polysiloxane gums in organic solvents, such as tolueneO A crosslinking or curing catalyst is then added to the dispersed low-solids mixture, the coating blend is applied to the substrate whichis then passed through an oven to evaporate the carrier solvent and cure the silicones to a relatively non-adherent release surface. This process requires a large thermal energy input in order to properly evaporate the solvents and effect the crosslinking reaction at commercially viable rat~s.

3~'7~7

- 2 - 60SI-311 Rising energy costs coupled with stringent environ-mental regulation of solvent emissions have made the use of solvent-borne silicone release agents increasingly uneconomical. While solventless or emulsion-borne silicone compositions can solve the environmental problems, high oven temperatures and expensive energy usage are still required for their proper application.
Radiation-curable silicone release compositions successfully address both the energy and environmental problems inherent in the use of traditional solvent-dispersed silicones. For example, an ultraviolet (UV) radiation-curable solventless silicone release composition eliminates the need for energy-intensive ovens as well as expensive solvent recovery apparatus. Such materials are not unknown; considerable litera-ture in the field of UV-curable silicone compositions has been noted in recent years, although commercial introduction of such products has not yet occurred. Applicant's Canadian Application Serial No. 365,247 filed November 21, 1980, describes epoxy-functional silicone compositions which are curable upon exposure to ultraviolet radiation and which utilize certain bis-aryl halonium salts as photoinitiators.
Several other UV-cure silicone systems have been described. Patents issued to R.V. Viventi (U.S. 3,816,282 issued June 6, 1974), Bokerman et al. (U.S. 4,052,529 issued October 4, 1977), and Colquhoun et al. (4,070,526 issued January 25, 1978) are representative of those compositions wherein omega-mercaptoalkyl substituents attached to polysiloxanes add -to vinyl-functional siloxanes in a free-radical process in the presence of certain photo-sensitizers upon UV irradiation. However, those silicone materials which include mercaptoalkyl func-tional protoactive substituents also posses an o~fensive odor (associated with the mercaptan group) which persists in the cured material.

~;!

The present invention provides newly developed radiation-curable silirone paper release cl _~sitions which do not require scarce or P~r~nqlve inputs. These novel compositions are comprised of acrylic or m~thacrylic-dimethylsilicone fluids which S will cure via well-known free radical processe~ when irradlated with W light in the presenc~ of standard photoinitiators.

Acrylic-functional si~icon~ are ~h~ ~ve~ not a new COI,C~pt. R. ~. Mercker described polymer~ prepared fro~ acryloxy-methyl and methacryloxy~ethyl substituted organosilicone i , u.dsin U.S. 2,956,044 which issued October 11, 1960. Merker's syntheses of acryloxymethyl-substituted sili~on~ r~quired chloro~
methyl-substitu~ed organosiljco~e~ as inputs~ Such 5ilicon~ are themselve~ prepared by h~ tion o~- methyl-substituted sili-I5 cone3 or by reaction o~ h~si~ with Grignard leage~-L~
fol7~ued by hyd~olysis in order to ~oduce the desire~ polymer.
Neither of these processes i~ well-suited to large scale co~mercial production, and chloromethyl-substituted silicone pol~mers and ~. rs are scarce and e~pensive materials Anothes synthetic route to acrylic-sil~y~ne compositions is taught by Nordstrom and Zelek ~.S. 3~50,811 which issued March 3, 1972). The Nordstro~ et al. synthesis involve~ the reaction of ~ g~ hydro~yalkylacrylates or methacrylate~ with silanol-con~a;n;n~ silicon~ in the presence o~ co~n~ation catalys~s such as tetrai-~opLo~yltitanate. In praotice, the resulting acryloxy-substituted poly~ers are severely lLmited ~ince the reactive acrylic group3 are con~i~ed to the ~hain~Lu~er position ~i.e. at the endR of the linear polymer molecule~). The lack of reactive sites on ~he polymer chains cause~ the free-radical crossl in~ing reaction between the acrylic moieties to 7 6osI-3 proceed very 510wly, rendering such co~lpo~itions impractical for high-speed proces~ing operations co~mon in the paper convertin~
industry.

U.S. Patent 4,201,803 - Cully et al, disclose~ paper release compo~itions curable by radiation consis~ing of acrylo~y-group-cont~inin~ silicn~ fluid plu~ polyacrylic-crosglinki~
agent~ and pho~s~n~it$zers a~,needed. Although the Cully et al.
diR¢105Ure i8 related to the composition~ of the present in~en-tion, there are ~ignificant differences bet~een the materials described by Cully et al. and those disclosed in the present application~ Most L~pOrtant~ the Cully et al. disclosure specifies that their coating composition must consist of tw~
parts: the acrylo~y-functional silicon~ fluid plu~ at lsast 10 (with 50~ bsing preferr~d3 of a polyacrylate . - -r such a~
trimethylolpropane triacrylate ~i.e. a non-silicone reactive diluent~ The coating compo~ition~ of the presant invention do not require reactive diluents or crosslinkers while providing useful rates of cure~ Nor are such ma~erials required for good release propertieg. Furthermore, the compositions of the pre~ent invention provide useful release chara~eristics yet consist solely of an ~crylic-functional silicone fluid with photo sensitizers as needed. ~dditionally, although the Cully et al~
disclosure does not specify any particular preferred mod* of manufacture of the acrylic~si l~ne fluids described therein, the examples provided by Cully et al~ appear to suggest that hydrosi-lation addition of allyl(meth)acrylate to hydride ~luids is the synthetio route utilized. Wherea~, on the other hand, a signifi-cant feature of the pre~ent disGlosure is the production of acrylic-Eunctional ~ilicones via consecutive addition o~
tmeth)allYlchloride and acrylic acid to hydride Eluids a~
described herein below.

60S~31 The COmpQSitions of the present invention herein describ~d do no~ su~fer from any of the inherent disadvantages discussed above. All of the inputs for synthesis of these W -curable paper release composltions are inexpensi~e and readily av~ hle. The synthesis itself is an easy stepwise procedure which ca~ be performed in a qingle reaction vessel i~ desired.

It i~ therefore an object of the present in~ention to provide novel acrylic functional ~ilicone composition~ and copoly-mers which are capable o~ being crosslinked upon exposure toultraviolet radiation..

It is another object to provide a~rylic-~unctional polyorganosilox~nes and copolymers of such silo~anes by a proces~
compri~ing the steps of addin~ allylchloride ~na acrylic acid to hydride-can~aining si~ An~

It is another object to pro~ide processes for the synthesis of acrylic functional silicones for use in release coating appll~
cations~

It is another ob~ect to provide ultraviolet light curable acrylic Punctional silicone releas2 coating compo~ition and methods for use.

These and other object~ will b~come apparent to those ~killed in th~ art upon consideration o~ the--following descrip~
tion, e~ample~ and claim~.

Summary of the Invention The present invention provides acrylic functional silicone co~po~itions and silicone release coatings made ~rom such compo-3itions as well a~ processes for providing the same~

An acrylic ~unctional polyorgano~3t~ne composition of the pre~ent invention is comprised of the reaction pLOdU~L of a number of constituent ingredients~ me rela~ive proportions of these components are not at all critical and may be varied over a wide range to provide acrylic-silicone composition~ having varied properties. The ~ethod described below describes a simple and preferred two-Rtep synthesis, bu~ it will be recognized that alterations in the synthetic procedure can ~e ac omplished if desired without detracting fro~ the spirit of the present invention.
The instant acrylic functional polyorganosiloY~ne composi~
tion~ will ha~e a first cl :~n~ comprised of an omega-halo alkene and preferably an omega-chloro-l-alkene such aR allyl cbloridet 4-chloro-1-butene, 10-chloro l-decene, and othes analogou~ unsaturated halogen-containing hydrocarbons.

Of course~ it will be recognized that mixtuses of such omega-halo-alkenes will also be useful. Ordinarily9 from 0.5 to 50 weight percent of such allcenes will be used compared to the 2 5 total weight o~- ~he--- acrylic--functional- silicone- composition reaction prod~ctO

The next ~ nt i5 a dialkylhydrogen chain~to~ed polydialkyl alkylhydrogensi~ e cop~lym~r~ Such a hydrogen ~a~ 7 functional siloxane will ordinarily have the ~eneral formula:
R ~ R ~ ~ R ~ R
t i ~yt ~ ~ z wherein each R represents, independently, a monovalen-t hydrocarbon radical such as methyl, ethyl, phenyl or tri-fluoropropyl, but will ordinarily be a methyl radical, R' represents, independently, the same monovalent hydrocarbon radicals as for R but may additionally represent a hydrogen atom, y plus z is an integer of, approximately 25 to 600 such that the si~oxane fluid has a viscosity of 20 to 5000 centipoise at 25C and preferably 100 to 500 centipoise.
Such hydrogen functional siloxane fluids are primarily linear and will therefore have an R to Si ra-tio of approximately 2 to 1. However, minor and insignificant amounts of mono and trifunc-tional siloxane uni-ts, some of which may also contain hydrogen, might also be included without seriously detracting from the usefulness of such fluids. These siloxane fluids will ordinarily have 0.5 to 50 weight percent hydrogen-siloxy functionality, and are made by processes well known in the art.
The alkene component and the hydrogen functional siloxane component are reacted in a precious metal catalyzed addition cure reaction which is a partial cure or precrosslinking reaction described in detail below. Such catalysts are well known in the silicone art and will ordinarily be a platinum metal complex effec-tive for adding hydrogen to the double bond of the alkene. Ordinarily approxima-tely 50 parts platinum metal per million parts of siloxane will be effective to promote this hydrosilation reaction. Examples are those exemplified in U.S.
Patents 3,220,972; 3,~14,730; 3,775,452 and 3,715,334.

A 1~

i7~

particularly useful are those platinum catalysts derived from chloroplatinic acid which has been treated with tetramethyldivinyldisiloxane, as described in u.s. 3,81a,730.
The final component of the reaction mixture is an acrylic monomer which adds the acrylic functionality to the silicone compositions of the present invention. A
wide variety of acrylic monomers are effective, including acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and other (meth)acrylic acid estexs containing a reactive hydroxyl group, including multifunctional acrylic monomers such as pentaerythritol triacrylate. Ordinarily, approxima-tely 0.2 to 30 weight % of this acrylic material based upon the weight of the total reaction product will be effective for provlding an acrylic-siloxane copolymer having 0.5 to 50% acrylic siloxy functionality.
The acrylic-silicone release coaiing compositions are comprised of the above described acrylic silicone fluid which is further comprised of an amount of Eree radical photoinitiator which is effective for curing a 0.1 to 5.0 mil coating of said composition to a non~adherent film on a substrate such as paper upon exposure to an amount of ultraviolet or electron beam radiation which is effective for curing such coatings.
Approximately 1.0 to 10.0% by weight based upon the entire coating composition will ordinarily be an effective amount of photoinitiator. Among the particularly useful free radical photoinitiators are included diethoxy-acetophenone, benzophene, Michler's ketone, t-butylbenzoin e-ther and certain combinations of amines and aryl ketones well known to -those skilled in the art.

7~7 60S~ 311 _g_ The proce~s for providing the acrylic ~unctional polyorganosiloY~n~ c ~ition~ of the present invention ordinarily comprises the ~tep~ of reacting (A) 1 to 50 parts by weight of an omega-halo-alkene, (~ 50 to 99 parts by weight of a S dialkylhydrogen ch~in topped polydialkyl-alkylhydrogen s~loYAne copolymer; (C) an amount o~ precious metal catalyst e~e~tive for catalysiny a hydro~ilation reaotion bet..een saLd alkene and said S~1~Y~nP copolymer; and ~D~ 0.2 to 30 part~ by weight of an acrylic functional -: effective for providing a si 70~n~
copolymer having 0.5 to 50 weight percent acrylic siloxy unitsO

Description o~ the Invention The symbol - Si is well k~own in the silico~e art and s~ tically depicts the- non-reactive or non-functional portion of a large silicone polymerO Ordina~ily, the major portion o~ a si1i~ molecule (e.g. a dimethylsiloxy chain) does ~ot take part i~curing or `~rossl inking reactions nor in synthese~ ~involving the p~odu Lion of copolymersO ~hus the reactive species (e.g.
hyd~ogen and vinyl, epoxy or acrylic rad;:c~l~) which may be attached to the polymeric backhone are chemically more interesting ~or su~h reactions. Thus _ Si~ represents a large ilicone polymer having at lea~t one reactive or functional hydsogen ~5 attache~ thereto, either on the chain or at its terrin~ Pre-crosslinki~g~ o this int~ !~iate p~lymer can be accomplished by ~Imul~neou~ly reacting a dimethylvinyl-s-o~ped linear dimethyl-~llicons fluid and (meth)allyl' chloride with a polymer con~inin~
one or more alkyl-hydrogen siloxy units or dialkylhydrogen silyl chain-stopping units.

The expression "pre-crosslinking~ represents a partial cure or crosslinkln~ reaction whlch i~ controllably allowed to proceed at an early stag~ in ~he synthe~is o~ th~se si lioo~P materialsO
Thi9 partial cro~linking serves the very usef~l purpose of enab-S ling a ~a~t, tigh~ and complete final cure to take place with relatively very little ene~gy input apon ~Yro~llr~ to a small amount of ultraviol~t lightD Since the silicQ~e material i~ only partially crossl;n~ed, ~.~., rp~ecLo~slinked~ it is ~till work-able a~ a coating ~-~ sition yet qui~e o~r~hl~ of a quick cure ~o a final non-adherent surface such as a release coatins.

In general terms, acrylic functional silicone polymers are provided as follows: first allylchloride is reacted with an - Si~-functional dim2thyl si~icon~ fluid in the presence of a cat~lytic a~un~ of ~ group VIII preeious metal hydrosilatio~
catalyst, thereby yi~ i n~ a- g~mma-chloL~pL~pyl-functional dimethyl.cili~onP copolymer via ~tandard hydroqilation additiond Next the resultant gamma-chlo~op.~yl-methyl silicone fluid i~ trea~ed with acrylic acid, methacrylic acid, or 2-hydroxyethyl acrylate or methacrylate in the pre~ence of a tertiary base such a~ triethylamine ~Et3N) or pyridine to yield an acrylic functional silic~n~ polym~r. Thi~ series of reaction can be depicted.in the following fashion:
Si~ + ClC~2C~ ' C~2~-~iC~2C~2~2 ~2) - SiCH~CH2C~zCl ~ HOOCC~ = C~2 + Et3N ~-i~
-i~ Et3N-HCl~ + SiC~2C~2c~zOocc~ = C~2

3~ The amine hydrochloride salt i8 a solid precipitate which can be easily r~ vcd by ~iltration. Any omega-chloto l~alkene C~D b~

7~'~
60S~-311 utilized in place of allylchloride in step [1] (e.g.~ 4-chloro-1 butene, 10-chloro-1-decene, etc.) but allylchloride is inexpensive and easily obtained and is preferred.

S Persons s~ e~ in the art will rec~gnize that this pLocedure o~fers several advan~age~ over previously described syntheses o~ acrylic-functional 3ilicQ~. Mo~t imp~rtant; this proce~ versatlles acrylic-functional Si7iC~n~S ca~ be prepared with up to lQO~ acrylic ~unc~ n~ y either on the polymer chains or as chainstoppers; also, the polymer may easily be modified by inclusion of other vinyl-functional groups (such as . vinyl-stopped polysil~Y~nes) with allylchloride in the hydro-silation step. m e re~ultant acrylic-functional silicone are hydrolytically ~table, since the acrylic moiety i~ bonded to silicn~ through an alkyl group rather than through an oxygen atom7 Another adYantage i~ tha~ the inte -d;ate g - chloro-propyl-substituted siloxanes need not be isolated; the total amount of acrylic functionality in the product will be determined by the amount and nature of the -- SiH present in the input .Q;lico~ fluid~

C.L. S~hilling and C.S. ~qchhack, XIV Organosilicon SymposiLun, Fort Worth, Texaq? M~rch 28~ 1980, have described important difference~ in reactivity between methallyl or allyl c _~L ` and = Si~-cont~inln~ substances in platin-L~n-catal-yzed add~tion reaction~. It wa reported that methallyl ~ L '~
provide higher yields of hydrosilation products than do the allyl counterpart~ and that these higher yields result fro~ le~s exten-sive side reaction- such as isomeri~ation and el;~;~AtionO

'7~

The above-described two-stage synthesis o~ acrylic-functional ~ilicone pol~mer fluid~ can be repeated with a processin9 difference being the substitu1:ion of methallyl chloride ( 2 ( 3) 2 ) for allyl chloride (C~2 =C~C~2Cl~ in the ~irst ~tep of the syn~he~is. Examples 4 and S below demon~trate the utility of this methallyl c:hloride approach.
These two example~ can be ch~mically represented by this reaction scheme:
(1) ~+C~ ( 3) 2 ~ ~ 2 ( 3) 2 (2)--SiC~2cH(c~3)c~2cl~0cc~ 2 3 ~ Et3N-~c~ 2C~(C~3) 2 It 2 m ese syntheses ~ay be carried out in a single reaction flask~
which simplif ies processiDg . It should also be pointed out that the reagents utili~ed (methallyl chl~ride, acrylic acid, and triethylamine) are all inexpenqive and commercially a~ailable material30 The use o~ methallyl chloride in place of allyl-chloride does not preclude the use of 2-hydro~yethylacrylate or other hydroxy-containing acrylates or methacrylate~ rather than acrylic acid5 also, any tertiary amine hydrogenchloride acceptor may be substituted for triethylamine without affecting the product. It has also been es~hlishe~ that multifunction21 acrylate ~-u ? rs containing Gne or more hydroxyl groups may be u~ed in plac~ of the hydroxyl-con~Ainin~ monofunctional acrylate i~n -r~t heretofore specified as th~ ~ource of reactiv~
photo-crosslinkin~le acrylate functionality~ ~xa~ple 10 below i~
illu~trati~e of this effect~ The reaction of ~ gamma-chloro~

f-~7 ~OS~-311 isopropyl~functional siloxane with pentaerythritoltriacrylate (PET~3 in the presence of an amin~ can be represented in this fashion:

--si ~ Cl + ~o~2C(C~2 ~ C~ 2 3 3 --3D

~--si ~ o ctC~2 ~ C~ = C~2)3 3 wherein each mole of PETA reacting pro~ides 3 moles of acrylate.

In order that those skilled in the ar~ may better practice the te~chings of the present invention, the following e~ampl~3 are yiven for purposes o~ illustrating the inventio~ and are n~t intended to limit the invention. ~nless othe~ise specified~ all s~eights are given by percent., Description of the Pre~erred Emkodiments ~ E~ample l:

35 grams of allylchl~ride were dissolved ia 300 grams he~ne in a 2 liter flask eguipped with overhead ~tirrer, re~lux condenser, and thermometer~ Sufficient platinu~ cataly~t ( 2 6 complexed with tetramethyldivinyldisiloxane~ was added to provide approxi~ately lO par~ platinum per million parts reactant material. Next 300 gram~- o~ -a dimethylhydroge~-stopped linear polydimethylmethylhydrosiloy~ne copoly~es fluid havifig- an approximate visco~ity of 80 centipoise and containing 805~ -~ Si~
functionality (as a perce~t of methylhydrogen s.ilo~y units~ were slowly added to the allylchloride solution~ Following this , 7~7 hnSI 311 addition, the reaction mixture was refluxed at ~9 for 20 hours with co~tinued stirring, at which point infrared analysis detected no ~nreacted ~ Si~ groups~ The hexane and excess allyl cbloride were ~hen removèd b~ s~ripping at 70 and 30 ~m ~g pressure for two hours, leaving ~ hazy fluid product of 100 Cp5~ viscosity.
Next, 150 grams o thi~ fluid pLodUct were dispersed in 150 grams toluene with 0.01 gram hydroquinone. ~ mi~ctur~ of 15 grams a~rylic asid and 21- gr~m3 triethyla~ine were addeds a~d ~h~
complete reaction mix~ure was stirred under a nitrogen purge at loo for 30 minutes~ ~ white precipi~ate was formed during the reaction. Following the reaction, the produc~ was fil~ered and the toluene stripped~ of~, affording a cloudy brown acrylic functional silicone fluid having a viscoslty of 620 centipoise.

~xamPle 2:

30 gram~ allylchlo~ide and24 grams o~ a 150 centipoise dimethylvinyl-stopped linear dimethyl fluid and 0.05 grams of the sa~ platinum catalyst u~ilized in Example 1 were dissolv~d in 1 liter of toluene in a 3 liter flask~ Next, 300 gram~ of a dimethylhydrogen-stopped linear polydimethyl-methylhydrosilo~n~
copolymer, having a viscosity of 12U centipoise and containing 6.2~ Me~ functionality were slowly added to the allyl chloride mixture with ~tirring. F311Owi~g thi~ addition, the ~atalyzed reaction mixture was refluxed at 100 to llO~C for 2 hours, at which point no unreacted -- Si~ wa~ det~cted. The toluene 501~ent was stripped of~ to yield a clear fluid prod~ct. 200 grEms of the above product were d ispe.rsed in 600 grams toluene w~h 15 gra~
acrylic acid and 1 gram ~ydro~uinone~ 17 gram o~ pyridine w~r~
3 510wly added to the stirred solution under N~ atmosphere at roo~
temperat~re. A cryst~ ne white precipitate de~elcped immedi~
ately upon additio~ o~ _he pyridineO After stirring at 25 30 C

~ 7'~ 7 60SI-311 for aR hour under the nitrogen atmosp~lere, the solution was filtered, and the filtra~e wa~ then stripped to remove toluene solvent. A hazy white acrylic Eunctional silicone fluid product was obtained, having a visco~ity of 340 cPntipoi~ev s Exa~ple ~

50 gram~ allylchloride and 40 grams dime~hyl ~inyl-~Lo~d linear dimethyl fluid and . 05 grams of the same pla~in~ catalyst were dis~olved in 1500 gram~ toluene. 500 grams of the --SiM-functional fluid utilized in Example 2 above were slowly added to the stirring mixture; following ~his addition~ the complete reaction mixture was refll~Yed at 95 110 C for 4 hours at which time no unreactPd _ Si~ was detectedO ~nreacted allylchlorid* wa~
then stripped ~ff, and su~icie3lt toluelle ~ai remov~d under ~acuum to increase the solid~; content s:~f the product solution to 509~ by weight. Tnen, 3~8 grams of thi~ solutior~ wer~ transfe~red to a 1 liter flask, and 19 grams o~ 2-hydroxyethylacrylate and ~1 grams hydroquinone were adde~l. 13 grams of pyridin~ were then addedl. to 2 0 . the reaction mixture under a nitrogen purge at 26 C. ~s in the examples above, a cryst~ll ine pre~ipitate for~ed a8 the amine wa~
added~ Following the addition of pyridine, the total reaction mass wa~ filtered, and tol~n~ stripped out o~ the filtrate to furnish a hazy acrylic ~unctional silicone ~luid pr~ucL having a 2 5 viscosity of 500 centipoise.

Example 4-Another acrylic ~unctional polysilo~ne was prepared in a fashion analogous to Example 3, except that 2-hydro~yethyl-methacrylate wa~ substituted in this synthe~i~ for 2 hydroxyethylacrylate in the previous 3ynthQ~i~, yielding a methacrylic-function~l sili~one fluid PL~dUCLO

E~camp.l~ 5O

33û gral~a o~ - the ~Si}~ :Eluild utilized in ~ Le 2 were ~lowly added to a solutlon o~ 33 gram~ allyl chls: ride a~d 26 gram~
of l~h~? vinQl ~luid utilized in ~ 2 and ,.1 gra~ oiE the ~
platinula cataly~3~ in 5f;10 gram5 tc~ïu~n~n Af1:er re~ g 'chis mix~ure a1~ 110C~ fo~ 4 hou~ all rea~tiv~ --Si~ wa~ c~n~
Alt thi~ polnt any e2cc:ess allyl chloride wa~ removed by stirring the rea~:tion mixtuse under 25 m~ }~ vacuum ~or 30 minute3 at 34 C. Next, 25 grams ac~ylis: acid were then added with .05 grams hydr~ui none. 35 gram~ triethylamin~ were slowly adde~d ~o the reac~ion mixture under a nitrog~n pu~ege at 32 pot temperat:ure~, The coloplete mixture Wa8 ~ n-e ~ to Ytir ~o~ 16 hour~ at roo~ te~p~ratur2~, ~hen to~n~n~ wa~s r~ ~_d by va~utam 3trip at loo&- The final PL~;IIICL wa~ ob~ ~9 a~ a clear yellow visco~ls luid a~ter removal of Et3N EIC1 precipitate via filtration.. It should be rloted that the proo~.sing described above ~Ja~3 a one kettle pLOCe:l&~

Ultraviolet evaluation~ described herein were accomplished using a PPG model 1202AN W Proc~sor. The PPG device u~ s 2 0 two ~anovia medium-pr~sure mercury qapor W soul.ces delivering 300 watt~/~quare inch ~c~ powor to irradi~ted surface~.
SalDple3 to be ~xpo~fl to W light are af~ixes~ to a rigid ~arri~r board, then paæ~ed under t~e lamp~ on a cvl ve~x~:r belt whi;:h opeE-ates at vari~ble speedæ from 5 to- 500 ft~miDute resulting in 2 5 expo~ur~ tiMes var3!ing from about 6 to 0. 06 S~CQr~S for any ind~
vidual pa~s u~3er the lamp~.

60SI-31l ~17-The effica~y of these acryli~ or methacrylic-functional ~$1icone fluids as W -curable paper release coatings wa~ deter-mined in the follo~ing fa~hion: lO gram s~nple~ o~ candidate fluid~ were cataly~ed with 0.5 grams of Trigonal 14 ~trademark of Noury Chemical Corporation) W cataly~t. Trigonal 14 is a stand~rd benzoin eth~r-derived fr~e-radic~l photoinitiator.
Catalyzed blends w~re applied a~ 0O5 ~il coating~ to 4~ x 10~
section~ of 40 pound s~percalendered ~ra~ (SCR) ~tock by mean~ of a doctor blade. Samples so coated were loaded onto the moving io conveyer and exposed to the W radiation under inert atmosphere for varyin~ amounts of time dependent on line s~eed.

Following e~po~ure, ~he re~ultant films were evaluated ~or cure and for their potential as relea~e agentQ by qu~litatiYely determ;nin~ the resp~sti~e film~' rub~off, s~ear~ and ~igration characteristic.~, Rub-off occurs when a cured silicone coating will not adhere to a sub3~rate and can b~ rubbed of~ in little ba11s of 29 silicone by u~ing finger pres~ure. Smear i8 defin~d as an incom-p1etely cured coating which displays an ob~ious, permanent streak when a finger is firmly pressed across it. ~igration is detected by the Scotch ~regi-qtered trademark of the ~ Company) cellophane tape test. The coating is considered to be well~cured and migration-free i~ a piece of Scotch tape will stick to itself after having ~ir-~t been firmly pres~ed t~ the coating, then removed and doubled back on itself, If A CoatiDg i~ miyration-free by mean~ o~ the Scotch tape test, it is presumed t~ be a relea~e coating, a~ it ha~ been shown to adhere to the s~b~trate with an adhesive force much greater ~han the adhesive ~or~e betwee~ the cur~d ~ ltion and ~he rsl~a~ed a9~re~sive ~cotch tape adhe~ive.

ll.~Dti747 60SI-311 When catalyzed ~nd coated as de~;cribed above, all of the candidate material3 synthesized irs Examples 1 through 5 ~ere found to cure to non-adherent coatings on SC~ he W exposure times required for cure to smear-, rub-off-, and migra'cion-free surfaces S are noted in the table belows W Activ~ Mini UV ~E~81lr*
Fluid Functionali~r* Pc~r Cure Example 1 ~}~2CH2c~20occ~3=c 2 3.0 sec.
Example 2 -ci~2C~2c~2cc~[2 1. 5 sec, E~cample 2 2 2 2 2 =C~2 lo S sec, ExalDple 4 C:~2C~I2CH20C~ 2Q~c (C~3) ~2 5 ~ O sec Example 5 -C}I2c~2ca20Qct~2 1. 5 secO
Reactive group attached to silicon atoms in the dimethyl silicone fluids.

~y~min~tion of the aforemen~ioned data r~ve31~ that acrylic-functional silicones will cure faster than analogous methacrylic functional silicones under otherwise identical condition~. Also, 'pre-cros~l~nked' acrylic-functional polymer~ lin which a vinyl-stopped dlmethyl fluid wa~ mi~ed with allyohlorid~ in the hydrosilation addition step of t~e synthese~) show significantly faster cure rate~ than strictly linear polymers.

Example 6:

64 ml. o~ methallyl c:hloride (u9ed as furni5h~d by Aldrich Ch~ ical t::o.~ and 0.5 gralo~ of a platinum-oct5rl Al~Qh~)l comple~c (a~
prepared in accordance with the disclosure of 1108~ 3,220~9723 ~hich 3 7f~ ~ 6OSI-3l:L

provides, appro~imately, 20 ppm pLatinum were dissolved in 200 ml.
of toluene in a 1 liter flask. 200 gram~ ~f a 95 centipoise viscosity dimethylhydrogen-chainstopp~d polydimethylmethylhydro-gensiloxane copolymer fluid containing ~.9~ Me~ siloxy uni~s were slowly added to the ~t.irred toluene solution over a 30 minut~
period. Follo~ing thi~ addition the complete reaction mixture was re1uxed at 95-110C for 15 hours; at which point no unreacted Si~ could b~ de~e~ted by inPrared spectsoscopy~ Exce~ m~thallyl chloride was re~oved under ~acuum 2t 50 C. 2~ gram~ o~ acrylic acid were then added to the flask along with 0~01 gra~ hydro-guinone~ 33 grams of triethylamine were slowly dropped into the reaction mixture under a nitrogen atmosphere~ A white precipitate was n~ted a3 svon as tho amine w2s introduced, additionally, a~
exotherm was observed at this time raising th~ flask t~mperature from 25 to 50 C~ Following additio~ of the amine ~he reac~a~s ~ere heated to 113C fos ona hour. Toluene solven~ plu~
unreacte~ acrylic acid and triethylamine were removed by stripping the product mixture in vacu~ at 150 . Filte~ing the fla6k content~ afforded 150 gram~ of a clear~ pale yello~
acrylic-functional silicone ~luid produ~t, ha~ing a viscosity of 217 centi~oise.

Exa~pl~ 7:

51 ml. of methallyl chloride, .05 graMs of th~ platinwm catalyst utili~ed in Example 6 were dispe~sed in lS0 gram~ toluene~
to which solu~ion 287 gram~ of a 150 centipoi~e visc08i~y dimethyl-3C hydrogen-chainstopped polydimethylmethyl hydrogen-s;7O~re ~opoly mer fluid con~ini~ 7.3% ~thylhydrogenslloxy units were qlowly 7 ~
60$I-311 --~0--added. Refluxing this solution at 115 for 16 hours removed all reactive ~ Sl~ fro~ the reaction mixture. After stripping off exces~ methallylchloride, 25 grams acrylic acid, ,01 grams hydroquinone, and 35 gram~ triethylamin~ were added to the ~eaction S fla3k a~ de~cribed in Example 1. F~llowing the ensuing reaction~
the solve~t and e~e~R re ctants were stripped o~f in vacuo, the product filtered to furnish - 240 gra~ of a ha~y yello~
acrylic-functional silicone fluid having a 570 ce~tipoise vi8c08ity.

Cure result~ a~e comparable to those reported for composition~ prepared via allylchloride addition described in previous exa~ple~.

E~ample 8:

Because the Gure mechanism fos acrylic materials free radical initiated, election beam irradiatio~ will also cure these acrylic-silicone release fluids~ Materials prepared in this fashion~ when mixed with effective quantities o~ standard photo-initiators and coated onto paper substrates, will cure to non-adherent surfaces when irradiated with either ultraviolet light or electron beam radiation in an inert atmosphere. For example r 10 gram samples of the acrylic-functional silicone fluids of Exam~les ~5 6 and 7 were each mixed with OA5 grams diethoxyacetophenone (DEAP9 Upjohn Co.) and the mixtur~s were applied to 40 lb9 SCR paper with a doctor blade. These coatings were cured by paqsing them under ~ocused ultraviol.et radiation supplied by two Hano~ia medium pres ure mercury vapor W lamps deli~eri~ 30n watt ~inch radiation housed in a PPG model 1202 AN Pro~esso~D Cure was qualitatively de~ined as formation of a -smear-, mi~ration-~ and ~ 7~ ~0~I-3~1 rub-off free non-adherent surface as described aboveO Quantita-tive measurements o~ the release propertie~ o~ cured film~ of the new co~position~ were al~o ob~ained. After ~be cured ~ilicone coated 5CX sampIes w*re aged at ambien~ conditions for 16 hour~, a 6 mil thick layer uf. an aggres~ive SBR preqsure ~ensitive adhesive obtained from Coate~ P.oaui~t-~, IncO was applied on top o~ the qil1con~ layer, then Gure~ fo~ 10 minut~ at r~o~ temperatur~ ~d 2 IDinUte8 at 150~; ~ second sheet of SC~ .~tQC~ wa~ ~then fir~ly pres3e~ onto the adhesi~e layer. Lamina so prepared were cut int~
2x9 inch strip~ and aged at 75 F for at least one ho~rO Release testing o~ these laminates was then accomplished by pulling the SC~/silicone lamina fro~ the SR/adhesive lamina a~ an angle o~
180 at a rate o 400 inches per minute. Th~ fo~ce required to separat2 the two l~mina wa~ recorded in gram~. Results of a ~V-cure and relea~ te~ting are sum~arized belowo Compo~ition W Cure Time Release Example 6 3.0 sec. 50-70 grams EXam~le 7 1~5 sec. 60-80 grams BcamE~l~ 9:

The following example~ illustrate how air inhibition of acrylic-3ilicone cure ca~ be overcome by proper choice o~ photo-sensitizers. A composition was prepared in fashion analogou~ to Example 7 above resulting in a 549 centipois~ viscoqi~y fluid peo~u~L containing 10 mcle ~ acryloxy-~ub~tituted siloY~ne groups randomly sequenced along the linear chainq of the pol~mer. 10 grams of this material were mixed with 0.4 gra~s o~ a 50% solutio~
o~ b~nzophenone iD. N-vinylpyrrolldin~n~ plu8 0.3 gram~

74~

N-methyldi~thanolamineO Suc~ a combination of photosensitizer~
and photoacti~atorQ is well known to persons ~killed iD the art and their use i~ taught in U.S~ Patent 3,795,807. This coating bath was applied to specimenQ of 40 lb. SCR with a doctor blade, the coated paper wa~ then P~p~se~ to two ~ano~ia medium presRure mercury ultraviolet lamp~ mounted in a PPG Proce~sor a~ described previously, except that an air a; -_~`ere was selected rather tha~
nitrogen. Smear-~ree aDd migration-free non-adherent coatingB
were o~tained upon O.S seconds exposure to W radiation under these conditions. 60 to 100 grams release versus a Coated Products aggressive SBR wet adheei~e was observed for thiQ cured material (release wa~ determined as described previously)~ By way of comparison, when the same composi~ion as found in E~ample 7 was catalyzed with diethoxyacetophenon~, it would ~ot cur~ in an air enviornment.
Example 10:

An acrylic silicone ~relea~e compositi~n was made in the following fashion: 200 grams of a 220 centipois~ viscosity ~5 dimethylhydroge~siloxy-stopped polydimethylmethylhydrogensil~Y~ne copolymer fluid having 8 wt. % methylhydroge~ siloxy units on the polymer chain were weighed into a 1 liter fla3k. A total of approximately 0.27 moles re tive ~ Si~ functionality was present. 20 grams methallylchloride and O . 05 grams of the same platinum catalyst utilized in EXample 1 were then added and the mixture wa~ re~luxed in- 250- gra~s toluene---fo 90 mi-nutesO At the end of ~hi~ reflu~ period le53 than 0.1 wt % unreacted ~Si~
could be detected, and exce~ methallychlorid~ was then removed by distillation of 50 ml of solvent and th~ exces3 ~ethallychloride ~9 '~ ^3 ~ ~ ~ 60SI~311 at atmospheric pressureO Next, 17 grams acrylic acid (0.24 moles) and 9 grams p~taerythritol triacrylate (0.03 moleY) were then added to the reaction flask, th~n 36 gram3 triethylamine wer~
~lowly added to the stirring reaction mixture at a pot temperatur~
of 90 C. An exothermic reaction and a precipita~e of triethyli inehydr~chlsrid~ occurred as ~he amin~ wa~ added to the reaction mixtur~. The pL~Juc~ was then v~-. 3tripped to 1~0 C
and filtered to yi~ld 143 gram~ cf- a cloudy yellow me~hacryli~
silicone fluid prod~ of 525 centipoi~e visco~ity. Cure performance of the acrylic-silicone was tested by blending 10 parts o~ this fluid with 0~5 parts diethoxyacetophenone (DEAP), this mixture ~a~ coated onto 40 lb. SC~ paper with a doctor blade, and the silicone film was exposed to two focu~ed m~dium-pressure mercury Yapor ultraviolet lamp~ ia an inert atmosphere for a period of tlme suf~ici~nt to cure the ~ilicone to a non-adherent rel~a e coating a~ descri~ed pre~iouslyO Exposure times a~ brie.f as 0.15 seconds were sufficient to cure this mat~rial to smear-free and migration-free non-adherent surfaces. Faster cure was possible, but the resultant silicon~ fiLms were then easily 2 0 rubbed-off of the paper substrates.

It should b~ noted that this exampl~ illustrates the use o~
acrylic acid and PETA in an 8~1 molar ratio a~ twin sources o~
reactive acrylic unctionality. I~ principle, it should be 2 5 pos3ible to blend PETA (or similar hydroxy-containing multi-functional - -rs gucb a~ trimethylolpropanediacrylate) with a~rylic acid (or similar monofunctio~al ~1 ~s such a~
beta-hydroxyethylacrylate~ in different molar ratio5~ or to utili~e PETA alone, for the preparation of acrylic-silicone fluids according to the practic~ of this invention.

Claims (17)

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

1. An acrylic functional polyorganosiloxane composition comprising: the reaction product of (A) an omegahaloalkene; (B) a dialkylhydrogen chainstopped polydialkylalkylhydrogensiloxane copolymer; (C) an amount of precious metal catalyst effective for catalyzing a hydrosilation reaction between said alkene and said siloxane copolymer; and (D) an acrylic functional monomer.

2. A composition as in claim 1 wherein said omegahaloalkene is selected from the group consisting of gamma-chloropropene, 4-chloro-1-butene, l0-chloro-1-decene, and 3-chloro-2-methylpropene.

3. A composition as in claim 1 wherein said dialkylhydrogen chainstopped polydialkyl-alkylhydrogen siloxane copolymer has the general formula:

wherein each R represents, independently, a monovalent hydrocarbon radical; R' represents, independently, a hydrogen atom or a monovalent hydrocarbon radical; y plus z is an integer of, approximately, 25 to 600 such that said copolymer has a viscosity of, approximately 20 to 5000 centipoise at 25°C. and a hydrogen content of 0.5 to 50 weight % based on methylhydrogen siloxy unit functionality.

4. A composition as in claim 1 wherein said precious metal catalyst is a complex of chloroplatinic acid and a compound selected from the group consisting of octyl alcohol and divinyltetramethyldisiloxane.

5. A composition as in claim 1 wherein said acrylic functional monomer is selected from the group consisting of acrylic acid, methacrylic acid, 2-hydroxy-ethyl acrylate, 2-hydroxyethyl methacrylate, and pentaery-thritoltriacrylate.

6. A composition as in claim 1 further comprising an amount of free radical photoinitiator effective for curing a 0.1 to 5.0 mil coating of said composition to a non-adherent film upon exposure to an amount of ultraviolet or electron beam radiation effective for curing said coating composition.

7. An article of manufacture comprised of a substrate and a film of 0.1 to 5.0 mils of the composition of claims 1 or 6 coated thereon.

8. An article as in claim 7 wherein said substrate is paper.

9. A process for providing acrylic functional polyorganosiloxane compositions comprising the steps of reacting (A) 1 to 50 parts by weight of an omega-chloro-1-alkene; (B) 50 to 99 parts by weight of a dialkylhydrogen chainstopped polydialkyl-alkylhydrogen siloxane copolymer and; (C) an amount of precious metal catalyst effective for catalysing a hydrosilation reaction between said alkene and said siloxane copolymer; and thereafter further reacting (D) 0.2 to 30 parts by weight of an acrylic functional moiety effective for providing a siloxane copolymer having 0.5 to 50 weight percent acrylic siloxy units.

10. A process as in claim 9 wherein said omega-chloro-1-alkene is selected from the group consisting of gamma-chloropropene, 4-chloro-1-butene, l0-chloro-1-decene, and 3-chloro-2-methylpropene.

11. A process as in claim 9 wherein said dialkylhydrogen chainstopped polydialkyl-alkylhydrogen siloxane copolymer has the general formula:

wherein each R represents, independently, a monovalent hydrogen atom or a monovalent hydrocarbon radical; y plus z is an integer of, approximately, 25 to 600 such that said copolymer has a viscosity of, approximately, 20 to 5000 centipoise at 25°C. and a hydrogen content of 0.5 to 50 weight % based on methylhydrogensiloxy unit functionality.

12. A process as in claim 9 wherein said precious metal catalyst is a complex of chloroplatinic acid and a compound selected from the group consisting of octyl alcohol and divinyltetramethyldisiloxane.

13. A process as in claim 9 wherein said acrylic functional monomer is selected from the group consisting of acrylic acid, methacrylic acid, 2-hydroxy-ethyl acrylate, 2-hydroxyethyl methacrylate, and pentaerythritoltriacrylate.

14. A process as in claim 9 further comprising the steps of adding an amount of free radical photoinitiator effective for curing a 0.5 to 5.0 mil coating of said composition to film having a non-adherent applying exposed surface applying a coating of said composition to a substrate, and exposing said coating to an amount of ultraviolet or electron beam radiation effective for curing said coating.

15. A process as in claim 14 wherein said free radical photoinitiator is selected from the group consisting of alkylbenzoin ethers, benzophenone, diethoxyacetophenone, and Michler's ketone.

16. A process of coating a substrate to provide an article of manufacture comprised of said substrate and a film of 0.5 to 5.0 mils thickness of the composition of claim 1 coated thereon.

17. A process for providing an article as in claim 16 wherein said substrate is paper.