CA1121532A - Silicone paper release compositions - Google Patents

Abstract

Abstract of the Disclosure A paper release coating emulsion composition comprising a vinyl-containing polymer of the formula,

Description

Background of the Invention l!
. . , The present invention releates to silicone paper release coating emulsion compositions and more particularlyJ the pxese nt 1' invention relates to paper release silicone coating emulsion compo-1¦ sitions which can be cured either with a tin catalyst or a platinum catalyst.
~¦ Silicone paper coating compositions are well known.
¦I Txaditionally, such systems comprise a silanol terminated diorganol polysiloxane polymer, a hydride polysiloxane cross-linking agent and 0 !j a tin salt of a carboxylic acid as the catalyst. Other additives ~! were added to these ingredients and the total ingredier~ s were then ¦l emulsified with the appropriate emulqifying agents in water to prepare a silicone paper treating emulsion. The resulting emulsion was then applied to paper using various types of equipment so as 1 to apply a coating of silicone of about 1 to 3 mills thick on the paper.
¦ As so treated, such paper had vexy good release properties to pressure sensitive adhesives. Accordingly, such paper could be I applied as release backing over pressure sensitive adhesive tapes !1 and when desired the paper could be easily stripped off from the 1l pressure sensitive adhesive tape. Such pressure sensitive adhesive i1 tapes and the paper release tapes appended to the adhesive tapes j has widespread uses in the horne and industry.
~1 Accordingly, the need for silicones and other materials to !! make paper releaseable to pressure sensitive adhesive tapes is in , great demznd. Silicones are especially sought after as paper !

11;~153Z 605I-176 1l release coatings because they are non-toxic, they are inert to the ¦¦ pressure sensitive adhesives and also provide generally, a good release surface for pressure sensitive adhesives. Accordingly, Il the demand for silicones for this application has increased from 5 1l year to year. In line with such increase in demand of silicones 1, for such application there has developed a continued effort into Il obtaining better and better silicone paper release coatings.
'1 There was several criterion that were developed for the evaluation of silicone paper coating compositions so as to produce lO 11 good paper release coatings. Such criterion was that the silicone il coating should have the proper flow properties so it could be i applied with existing equipment and that the silicone coating should ' be such that the emulsion did not wet out the paper.
l Another desirable property for the silicone coating was that 15 ! it should have some abrasion resistance, that is it would not rub `
Il off when it was rubbed so that it would be maintained on the surface of a paper to act as a paper release coating. Also the coating i had to cure properly in the time allotted for the cure of the coating l within industrial limitations and did not require a po st-balce cure, 20 ~ thus decreasing the time necessary to process the release coated paper. The tin curing composition as mentioned previously, was ~
able to meet many of the above criteria. However, while inexpensive it did require a post cure and in addition, such tin catalyzed l silicone coatings also did not have as good abrasion resi stances 25 1 aa would be desired.

- 2 -1. i 11~153~ 60SI-176 Accordingly, one lmprovement in this area was the development of SiH olefin platinum catalyzed silicone compositions as coating compositions for paper. Such Si~ olefin compositions generally comprised a vinyl-terminated diorganopolysiloxane polymer, a hydride polysiloxane cross-linking agent and a platinum complex catalyst. While such platinum cured paper release coatings were more expensive than the tin catalyzed versions, they had the advantages that they were faster curing and required no post-bake cure. However, it was found that in some cases that such platinum catalyzed paper release coatings did not have as good abrasion resistance as would be desired.
Such platinum catalyzed coatings were formulated in the form of emulsions, since emulsions were easier to apply by traditional equipment.
Presently, there has been developed solventless systems both of the tin catalyzed version and the platinum catalyzed version. As disclosure of such solventless systems is to be found in the commonly assigned United States Patent ~ No. 4,162,356 which issued July 24, 1979. The advantage of such solventless systems is that they eliminate the need of emulsifying agents and solvents to produce the desired emulsions, which solvents and emulsifying agents would evaporate into the atmosphere when the paper release coating was dried, thus possibly creating pollution problems. Accordingly, for the extinyency of where the evaporation of the solvent and emulsifying agent vapors might cause pollution problems in a paper treatiny plant, the solventless systems were developed and have been found Il 60SI-176 ;Zl532 EPK/ jl ¦I satisfactory in this respect. However, such solventless syste~ns have not gained widespread use in the industry as yet, since they require special equipment to apply versus the emulsion systems.
1,l Accordingly, as stated previously, it may be desirable to 1¦ utilize in a paper treating plant two systems for producing paper -release coatings where it is desired to have an inexpensive system ¦~ in which the optimum of adhesive release properties are not that

3 important and one in which a post-bake cure can be utilized.
~ On the other hand, in the same manufacturing plant it may be ¦ desired to treat the paper with the paper release coating which has the optimum of release properties, which requires no post-bake cure, and which has good abrasion resistance. Accordingly, as can be envisioned in the same manufac$uring plant, it is desirable ¦
l at that time to switch from one paper release coating system to 1l another . In such plants it was found that after the tin system had been used, that extra care had to be taken to completely clean the i tin out of the equipment, o$herwise, the tin would poison the platinum if the platinum system was used subsequently. In addition, it was I found that in going from one syslem, the entire ingredients the re 'I
were to be used to treat the paper would have to be changed in i going from a tin catalyzed paper release coating system to platinum catalyzed silicone paper release system. Accor~ingly, it was ', highly desirable to provide or develop a single system which could be cured with either ~ tin catalyst or a platinum catalys$ in which ¦ the system would not be become poisoned by the tin i~ it was 1 decided to subsequently use platinum in the system.

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It was felt that such system could be devised by having the base polymer, a diorganopolysiloxane polymer which was silanol terminated and which had vinyl in the polymer chain.
A system disclosing such a base polymers is that to be found in Moeller U.S. Pat. No., 4,008,346 dated February 15, 1977.
This patent discloses a paper release coating emulsion comprising a vinyl containing base polymer having silanol terminal groups, a hydride cross-linking agent and a platinum catalyst. The distinction in this invention of the prior art is that the base polymer is produced by emulsion polymerization so that it is not necessary to emulsify the base polymer to produce the paper coating emulsion. It was determined by such emulsion poly-merization the viscosity of the base vinyl-containing polymer would have to have a viscosity in the range of 25,000 centipoise to 1 million centipoise at 25C. When it was attempted to cure such a polymer, that is the silanol terminated diorganopolysiloxane polymer of the Moeller Patent having vinyl in the polymer chain, it was found that such a polymer would not cure with a tin catalyst. It would only cure with a platinum catalyst.
As pointed out previously, the reason for the high viscosity of the vinyl-containing base polymer is the emulsion polymerization by which it is produced as disclosed in the foregoing Moeller Patent. Indeed, it was felt it was because of this high viscosity of the polymer that such a polymer did not have a sufficient silanol content such that it could be cured with a tin catalyst.

iS3Z 60 SI-176 i ¦l Accordingly, it was unexpected that a silanol terminated diorganopolysiloxane polymer havina vinyl on the polymer chairl, ' which was not produced by emulsion polymerization, but which was ,, emulsified could be cured with either a tin catalyst or a platinum il catalyst to p r oduce an acceptable paper release coating composition.' It should be noted that while the Moeller coating was an ¦ advantageous type of coating for paper release coating applications, ¦ because it was emulsified in process and it could still not be cured ~ with a tin catalyst and further did not have a very good abrasion ! resistance, that is in many cases, unless the composition was post-cured the coating would smudge or rub off when it was rubbed ¦
with a finger.
Accordingly, it is one object o~ the present invention to provide for a silicone paper release coating composition which can be cured either with a tin catalyst or can be cured with a platinum catalyst.
It is an additional object of the present invention to provide j for a silicone paper release coating composition which, when cured i with a tin catalyst or cured with a platinum catalyst has good abrasion resistance.
It is an additional object of the present invention to provide for a process for producing a silicone paper release coating compoT
sition which can be cured with either a tin catalyst or a platinum catalyst.
~5 ¦ It is yet an additional object of the present invention to ~¦ provide for a process for coating paper with a paper release coating ¦ composition which can be cured with either a tin catalyst of a i !
11'~153Z
, 60SI-176 EPK/ jl ¦ platinum catalyst. These and other objects of the invention are ¦l accomplished by means of the disclosure set forth hereinbelow.
Il , Summary of the Invention ll In accordance with the above objects there is provided by the present invention a paper release coati~g emulsion composition comprising (A) 100 parts by weight of a vinyl-containing polymer ¦ of the formuIa, i ¦ 1 R ' l ~ (1) H - 0~ Si 0 ~Si O~H

¦ where Vi is vinyl R is an aliphatically saturated monovalent l O ~I hydrocarbon radicaL R' is a monovalent hydrocarbon radical and ¦ x and y ~rary such that the polymer has a viscosity varying from I 1, ~)0 to 24, 000 centipoise at 25C; tB) from 1 part per million ¦ to 2 p~arts by weight of a catalyst selected from the class consist-¦ ing o platinum catalyst and tin soaps of carboxylic acids; (C) from ¦ 1 to 30 parts by weight of a hydride polysiloxane cross-linking ¦ agent; (D3 from 50 to 300 parts of water and (E) from 5 to 80 parts by weight of emulsifying agents. Preferably, the vinyl-containing polysi loxane is emulsified in water in an emulsifying l agent such as polyvinylalcohol with or without an organic solvent j such as ~ylene and then the hydride polysiloxane cross-linking agenjt is emulsified itself and then the two emulsions are mixed and applied to form the desired coating.

532 EPK/ jl il It should be noted that both the tin catalyst version and~ or platinum catalyzed version can be cured either at room temperature l or at elevated temperatures. As can be appreciated the cure at 1 elevated teInperatures is much more rapid than the cure at room 1! temperature. It should be noted more specifically that the tin ¦I catalyst is generally utilized at a concentration of .1 to 2 parts ¦~ by weight as tin of the tin salt of the carboxylic acid which tin ¦ salts is preferably dibutyltindilaurate. Another preferred tin catalyst is for instance di(N-octyl) tin S, S'-bis(isooctylmercaptoacetate) The platinum catalyst is utilized at a much lower concentration, ~¦ that is at a total concentration of 1 to ~ 00 parts per million platinurn and is preferably present as a platinum complex of platinum with a hydrocarbon selected from the class consisting of alcohols, aldehydes and ethers. The hydride polysiloxane can 15 ~ be arly of various kinds of cross-linking agents. Thus, the ¦ hydride polysiloxane cross-linking agent can be a hydride contain-¦ ing diorganopolysiloxane polymer of 1 to 250 centipoise viscosity at 25C or it can be a hydride resin composed of monofunctional silox~r units and tetraEunctional siloxy units or can be hydride siloxy resin composed of monofunctional siloxy units, tetrafunctiona L
siloxy units and difunctional siloxy units~ The particular forrn of the hydride cross-linking agent will be celected such there is ¦ obtained optimurn properties for a particular application of the 1 paper releas~ coating. -i 153Z EPK/ jl !-De scription of the Preferred Embodiment ~i .
In the compound of Formula 1 above, R is any aliphaticallysaturated or aromatic monovalent hydrocarbon xadical, thus R
~, can be selected from alkyl radicals such as methyl~ ethyl, propyl~
etc. cycloalkyl radicals such as cyclohexyl, cycloheptyl; mono-nucleax aryl radicals such as phenyL methylphenyl, ethylphenyl, I
e tc. and halogenated alkyl radicals more specifically fluoroalkyl, radicals of from 3 to 8 carbon atoms such as 3, 3, 3 trifluoropropyl~
Most preferably, R is selected from methyL ethyl and phe~yl ¦ radicals. The R' radical can be the same radicals as R and also including aliphatically unsaturated radicals such as vinyl allyl, etc.
Most preferably the Rt radical is a radical selected from alkyl radicals from 1 to 8 carbon atoms and phenyl radicals.
It should be noted that the R' radical can also be a 1uoro-allcyl radical of 3 to 8 carbon atoms such as 3, 3, 3 trifluoropropyl.
Most preferably the R' radical is selected from methyl and phenyl radicals. It should be noted that the fluoroalkyl substitution in the polymer of Formula 1 above would give a polymer which has I solvent resistance. Unless, it was necessary to obtain a paper ~ release coating that has solvent resistance, it would not be necessary ¦ to substitute or ha~e a base polymer in the paper release coating ¦ composition in which the substituent group was a fluoroallcyl radical.
~1 It should be noted that all o the R and R' radicals need ¦I not be 3, 3, 3 trifluoropropyl, it just being necessary ~at there ~ be sufficient amount~: of the trifluoropropyl substituent groups in i~ _ g _ li 1 ~lS~;~

the polymer so as to give the resultant paper release coating composition the desired solvent resistance.
As noted previously in the compounds of Formula 1, x and y will vary such that the polymer has a viscosity varying from 1500 to 24,000 centipoise at 25C and more preferably has a viscosity that varies from 2,000 to 10,000 centipoise at 25C.
It should be noted that viscosities above 24,000 centipoise in the base polymer of Formula 1 are not preferred since the compound will not cure in the presence of a tin catalyst. In order for the polymer to have the appropriate amount of silanol groups so as to cure with a tin catalyst the compound of Formula l should have a silanol content that varies anywhere from generally 650 to 2400 parts per million and preferably has a silanol content that varies anywhere from l,000 to 2400 parts per million. In addition for the same compound to be cured with a platinum complex catalyst, then it is preferred that the polymer have vinyl content which varies anywhere from .l to 2% by weight and more preferably varies from .2 to 1.5% by weight. Such a polymer can then be cured with either a platinum catalyst with the hydride cross-linking agent in an SiH olefin platinum catalyzed reaction or it can be cured with a tin catalyst in a condensation reaction with the silanol group in the compounds of Formula 1 and the hydride to form a paper release coating. The compounds of Formula 1 can be obtained by well-known silicone polymerization techniques. It should be noted that the compound of Formula 1 cannot be obtained through emulsion polymerization since as has been pointed out, - ld -11~153Z 605I- 176 it is not possible to obtain compounds within the scope of Formula l, i1 with as low a viscosity as the compounds of Formula l, through emulsion polymerization. To obtain the compounds of Formula l, ~1 the following procedure can be followed. The appropriate dimethyl-1' dichlorosilanes and methylvinylchlorosilanes are hydroly~ed in water. '~
The resulting hydrolyzate is then taken and there is added to it a sufficient amount of alkali metal hydroxide or an alkali metal hydroxide such as, potassium hydroxide and the resulting rnixture is heated at ¦ elevated temperatures so as to preferentially distill overhead and I obtain cyclotetrasiloxanes. The cyclotetrasiloxanes that would be obtained will depend, of course, on the chlorosilane hydrolyzate that was obtained.
Accordingly, proceeding with the fact that methylvinyldichlorosilane was first hydrolyzed there is obtained methylvinylcylcotetrasiloxane in high yields by heating the hydrolyzate with potassium hydroxide at elevated temperatures. The methylvinylcyclotetrasiloxane may then be taken and mixed with other types of cyclotetrasiloxanes, that is, cyclotetrasiloxanes having other types of substituent groups which ¦ cyclotetrasiloxanes are obtained by the exact same procedure. To such cyclotetrasiloxanes there is added any-vhere from 5 to 500 parts per million of potassium hydroxide and a sufficient amount of water so~
as to obtain the appropriate amount o chain-stopping in the polymer.
¦¦ It should be not~d that since water acts as a chain-stopper in this 11 reaction then the amount of water that is utilized in the reaction I mixture will deterrnine the polymer chain length and, of course, its viscoslty.

53Z 605I-l76 Accordingly, the appropriate amounts of water must be utilized so as to obtain a polymer of Formula l, which has the desired viscosity and the desired amo~mt of silanol content. The resulting mixture is then heated at temperatures above 150C, anywhere from 5 to 24 hours, during which period of time there is formed the compound of Formula 1. At the peak of the equilibration reaction as much of the cyclotetra-siloxanes are breaking up to form the polymer of Formula l, as there is o the resin of the poly~er of Formula l, breaking up the formed cyclotetrasiloxanes. Usually this point is reached when 85% of the c~rclotetrasiloxanes have been converted to the linear polymer.
It should be noted that although the compound of Formula 1 is sub-stantially a linear polymer, that up to 2% by weight of trifunctionality in the polymer can be tolerated. - This usually will result from impurities that may be present in the cyclotetrasiloxanes reactant.
However, it should be noted that a polymer w;thin the scope of Formula 1, can be obtained in which the amount of trifunctionality is con-siderably below 2%. Once the equilibration point is reached, the alkali metal hydroxide in the reactants is neutralized with phosphoric acid or a silyl phosphate, that is, the reaction product of a silo~ane and phosphoric acid, so as to neutralize the base. The unreacted cyclics are vented off or stripped off to yield the desired compound of Formula 1. The foregoing sompound of Formula l, may then be utilized in an SiH-olefin platinum catalyzed reaction or may be cured with a tin soap as w;ll be disclosed below. The resulting compound of Formula l, may then be emulsified in water using as an enlulsifying agent, poly-v-inyI alcohol, to yield an emulsion which may be utilized to form a ,~ 11;~153Z 605:,_ I 7 Il paper release coating. Since the platinum complex catalyst is ! normally incorporated into the compound of Formula l, when it ~! is emulsified,the platinum complex catalyst will first be discussed i, before going into the preparation of the emulsion. Any type of a I solubilized platinum complex catalyst can be utilized in the instant ¦I invention.
Many types of platinum compolmds for this SiH-olefin addition re-actio~ are known and such platinum catalysts may be used also for the reaction of the present case. The preferred platinurn catalysts especially when optical clarity is required are those platinum com-pound catalysts which are soluble in the present reaction mixture.
The platinum compound can be selected from those having the for-¦ mula (PtC12. Olefin)2 and H(PtC13. Olein) as described in U. S. Patent ! No. 3, 159, 601, Ashby. The olefin shown in the previous two for-¦ mulas can be almost any type of olefin but i~ preferably an alkenyleneI
~I having from 2 to 8 carbon atoms, a cycloalkenylene having from 5 to ' j~ 7 carbon atoms or styrene. Specific olefins utilizable in the above formulas are ethylene, propylene, the various isomers of butylene, octyl ene, cyclopentene, cyclohexene, cycloheptene, etc.
2Q A further platinum containing material usable in the composition of the present invention is the platinum chloride, cyclopropane complex I (PtCl2. C3H6~2 described in U.S. Patent No. 3, 159, 662, Ashby.
i Still, further, the patent containing material can be a complex formed ~ from chloroplatinic acid with up to 2 moles per gram of platinum of I I a m~n Iber: elected f rom the clas s c~nsi sting of aIcohols, ethe r s, Il l ~ S32 60ST-176 aldehydes and mixtures of the above as described in U.S.
Patent No. 3,220,972, Lamoreaux dated November 30, 1965.
The preferred platinum compound to be used not only as a platinum catalyst but also as a flame retardant additive is that disclosed in U.S. Patent No.3,775,452, Karstedt dated November 27, 1973. Generally speaking, this type of platinum complex is formed by reacting chloroplatinic acid containing 4 moles of water of hydration with tetravinyltetramethylcyclosiloxane in the presence of sodium bicarbonate in an ethanol solution.
Any of the above platinum complexes can be utilized in the instant invention. However, the most preferred are the Lamoreaux catalysts which is platinum complex formed with platinum and a compound selected from aliphatic alcohols, ethers and aldehydes and is more preferably a platinum complex formed from platinum, metal and an organic aldehyde as disclosed in the foregoing Lamoreaux patent.
The Karstedt catalyst which is also a suitable catalyst can be utilized in the instant case. The Karstedt platinum catalyst is especially desirable since it is a very efficient catalyst for an SiH-olefin platinum catalyzed reaction. Generally, the Karstedt catalyst comprises the reaction product of a platinum halide with vinylpolysiloxane wherein the final platinum complex is substantially free of chemically bound chlorine. It has been found that the Karstedt platinum catalyst is a very efficient catalyst and will allow very rapid reaction to take place between the hydride polysiloxane and a vinyl-containing EPK/ meo ~ 153Z

polysiloxane. However, the Lamoreaux catalyst is also suitable for use to produce a paper release coating within the scope of the !l instant case.
In forming the emulsion of the compound of Formula 1, with the 1 platinum catalyst, there may be added other ingredients to the ~¦ emulsion such as, corrosion inhibitors and bactericides. Accordingly, i! as an example there may be formed an emulsion by taking 40-50% by ¦1 weight of the vinyl fluid of Formula 1, 10 to 20% by weight of an ¦ emulsifying agent such as, polyvinyl alcohol, . 04 parts by weight of so~bic acid, which is a bactericide, . 20 parts of sodium benzoate as a thixotropic to prevent the resulting emulsion that is formed fro~n wetting in too rapidly into the pores of the paper that is treated, . 04% of platinum catalyst and 10-30% by weight of ~,vater.
To prevent bacteria from growing on the paper relea e coating once it has been used to coat paper or during storage f or that matter, I bactericide additives are used.
¦ It should be noted that the bactericides are needed in the silicone i! compositions of the instant case since silicones will traditionally ¦~ support the growth of bacteria. Accordingly, to keep the compo-1 sition as free from bacteria as possible and to prevent color degradations which result from the growth of bacteria on the silicone paper release coating, it becomes necessary to include bactericides in the em~llsion composition. With the above concentration of the !3 ingredients, the emulsion is forrned by charging the platinum catalyst 1l and the vinyl-containing compound of Formula 1, to a premixed tank.
Then the polyvinyl alcohol is added with continued mixing at moderate _ 15 -mixing speeds for 20 to 30 minutes. After the mixing has been , carried out, there is slowly added to the mixture the flrst quantity of water. The rate of addition and agitating should be sufficiently ,, slow to avoid inversion. There i5 continued agitation after the 1, above quantities have been mixed for an additional period of time of thirty minutes at moderate agitation s peeds. After that time then the second quantity of water is charged as well as the bacteri-cides. The second quantity of water and bactericides are then il uniformly mixed in the composition. Then the mixture is passed 10~ 1I through a Manton-Gaulin Colloid Mill at high speed using a 3-inch li rotostater with a clearance of ~ to lZ mills until the milling is ! complete. Then the paste that is formed should be agitated con-tinually in the blend tank at slow speed and for 20 to 30 minutes af~er the milling is complete. The rate of agitation in the blend tanks should be suf~icient to disperse the paste and slow enough to il avoid air entrapped. The resulting emulsion may then be filtered and be ready for use as such to produce a paper release coating l! within the scope of the instant case.

I It should be noted that the foregoing procedure appli es also when ¦ the compound of Formula 1 is to be cured with the tin soap. However, in that case the platinum catalyst is not incorporated in the emNlsifi-¦ cation procedure for preparing the emulsion of the compound of . I Formula 1. When a tin catalyst is prepared then the tin catalyst is ¦¦ ernulsified itself in a third separate emulsion and utilized as such to I form a paper release coating. When a platinum complex catalyst is ¦ u~ilized to cure the system, then as stated above, the platinum 60~I-176 I llZ~532 EPK/ meo complex is incorporated into the compound of Formula 1, when it is emulsified as was discussed above.
It should be noted that ~ith the platinum catalyst there is utilized a 1, platinum catalyst at a concentration of 1 to Z00 parts per million of platinum per 100 parts of the vinyl compound of Formula l. More -preferably, there may be utilized from 1 to 50 parts per million of ¦ platinum, as platinum of the platinum complex catalyst which is ~ based on 100 parts of the vinyl-containing polymer of Formula 1.
¦ Based on 100 parts of the vinyl-containing polymer of Formula 1, ~ there is also utilized as the cross-linking agent from. l to 30 parts ~1 by weight of a hydride polysiloxane as a cross-linking agent. The !! hydride polysiloxane can take various forms and can be any of the ~¦ hydride polysiloxane cross-linking agents which are well known for I SiH-olefin platinum catalyzed reactions. For instance, the hydride ¦ polysiloxane cross-linking agent may be a linear low molecular weight hydride polysiloxane polymer of the formula, (2) E~.~Si 0 ~ ; O L ~ 2 ¦ where R is selected from hydrogen and monovalent hydrocarbon ~ radicals and s and S: vary such that the viscosity of the polymer varies ~ from 1 to 250 centipoise at 25C and more preferably varies from 5 I! to 50 centipoise at 25C. The foregoing R2 radicals in compoun-~ of il Formula 2 above, that is, in the formula of the hydride polysiloxane of Formu1a 2 above, may be any monovalent hydrocarbon radical or - 17 ~

153Z EPK/ meo Il .
j halogenated monovalent hydrocarbon radical such as, for instance, methyl, propyl, phenyl, cyclophenyl, methylphenyl and 3, 3, 3-tri-¦I fluoropropyl. The R2 radical in the compounds of Formula 2 may also be selected from vinyl and allyl radicals. As long as the ¦~ platinum. catalyst is not incorporated in the hydride polysilo~ane Ii ingredient then the hydride polysiloxane of Formula 2 may contain !i aliphatic unsaturation. However, if the platinum catalyst is incor-¦¦ porated in the hydride polysiloxane cross-linking agent component then it could not contain aliphatic unsaturation since if it did, it would ¦
1 cross-link with itself.
It should be noted also that there can be hydrogen atoms on $he terminal silicone atoms in the polym.er chain as well as there can be hydrogen atoms only in the internal silicone atom.s in the polym.er chain. Most preferably, the hydrogen atoms are located only in the ¦¦ polymer chain since it has been found that a better cured product is ! obtained with hydrogen atom.s in the polymer chain. However, a suit-; able paper release coating w;ll be obtained where a hydrogen poly-siloxane of Formula 2 is utilized when the hydrogen atoms are only in the terminal positions of the polymer chain on the hydrogen atoms 1 !¦ or both in the terminal positions of the polymer chain and in the ¦l polymer chain itself. In addition to the definitions given above for the ¦¦ compound of Formula 2, it is necessarythat the compound of Formulal 2 have a hydride content that varies any~vhere from . 3 to 1. 6% by weight in order that * properly cross-link with the com.pounds of Formula 1 Z5 to prepare an appropriate type of release composition. A hydride polysiloxane of Formula Z aboveJ is also obtained by a standard ~,vell-- 18 _ ~! I

lS3~ EPK/ meo l l l known procedure. It is obtained by simply hydrolyzing the appropriate chlorosilanes in water and separating the hydrolyzate ¦l by simply decanting off the water acid layer from the resulting '~ hydride polysiloxane of Formula 1, and the hydrolyzate is then il purified by distillation fractionation techniques. Such distillation techniques also remove unwanted acid frorn the polymer such that it has an acidity below 15 parts per million so that it can be used as I a cross-linking agent in the compositions of the instant case.
¦ The polysiloxanes of Formula 2, must also be emulsified in order to j ¦ be utilized with the emulsion of the compounds of Formula 1, to pre-pare a platinum catalyzed paper release coating composition. Pre-ferred en~ulsifhing agents for such hydride polysiloxane are the alkylphenoxypolyoxyethyleneethanols where the alkyl groups in the compound has from 1 - 15 carbon atoms. Thus, in the emulsion of il the hydride polysiloxane, as an example, there is utilized from 40 -¦ 50 percent by weight of methyl hydrogen polysiloxanes and from 2 to ¦ 5% by weight of the emulsifier given before. There is also used a first quantity of water which varies anywhere from 2 to 4% and a second quantity of water which varies anywhere from 30 to 40% and finally a formaldehyde solution as a bactericide at a concentration of anywhere frorn . 1 to . Z% by weight. To prepare the emulsion, the hydrogen siloxane of l?ormula Z is mixed with the emulsifier and the first quantity of water is thoroughly mixed therewith This ~ mixture i~ passed through the colloidal mill and then the paste is , dissolved in the second quantity of water and formaldehyde sGlution. ~' After agitlation has been carried out for a suffieient tinne and dis-, 60SI-176 53z EPK/ meo !
Il pensing the colloidal mill paste in the second quantity of water, then il the emulsion is ready for use in the instant case.
il To apply the emulsions to form a paper release coating, the ~~ emulsions are simply mixed in the right proportion such that there ~l is from 1 to 30 parts of a hydride polysiloxane per 100 perts of vinyl polymer of Formula 1, in the mixture and the resulting emulsion ¦ mixture is then a~plied by known equipment to a paper so, upon evaporation of the water and with or without the application of heat, there results a silicone paper release coating on the paper. This ¦
system is a two-component system which is platinum catalyzed.
If * is desired to catalyze the system with tin then there is a three-component system comprising the emulsion of the polymer of For-¦I mula 1, the emulsion of the polymer of Formula 2, and finally the emulsion of the tin catalyst. In the three component system, all il three components are mixed and applied as an emulsion mixture to 1~ paper to produce a silicone paper release coating.
¦~ It should be noted that in the eventuality of this three component ¦~ system, that is, the system with a tin soap, then the platinum ¦ catalyst is not added or emulsified with the compound of Formula 1.
¦ It should be noted that preferably the platinum catalyst is not ¦ emulsified with the compound of Formula 1, but is kept separate, ¦ and when it is desired to have a platinum curing system the platinum catalyst is simply added or agitated into the emulsion of the compoundl of Formula 1, that is, the emulsion of the compound of Formula 1 ¦¦ is formed as indicated above but without the addition of the platinum catalyst and the platinum catalyst can be added subsequently at any 1~ i llZlS3Z 605I- 176 time when it is desired to have a platinum catalyst system by simply adding the catalyst and mixing it into the emulsion of the compound of Formula 1.
Another hydride cross-linking agent that might be utilized in the iI invention of the instant case is a hydride polysiloxane composed of H(R )2SiOo 5 units and SiO2 units where the H + R2 to Si ratio varies li from 1. 0 to 2. 7 and R is a monovalent hydrocarbon radical. Again ~¦ in this formula, R has the same defin;tion as given above for the R2 ¦ radical in the hydride polysiloxane of Formula 2. This second cross-linking agent is a hydride silicone resin composed of monofunctional units and tetrafunctional unit~.
~nother type of silicone resin that can be utilized as a hydride cross-linking agent is one composed of H(R2)2SiOo 5 unit~ and SiO2 units and H(R2)SiO units where the ratio of R + H to Si varies from 1. 0 to ¦ 2. 7, and the R is a monovalent hydrocarbon radical as given pre- l ¦
viously for the resin which only had monofunctional units and tetra-functional units and is the same as the R2 radical which definition was given previously for the hydride polysiloxane of Formula 2, that is, 1~ ~n the R2 radical in the hydride silicone resins, can be selected from 1 an allcyl radical of 1 to 8 carbon atoms, phenyl radicals, methyl-phenyl radicals and other mononuclear aryl radicals, cycloah'cyl radicals such as, cyclohexyl, cycloheptyl, cyclooctyl radicals and fluoroalkyl radicals such as, 3, 3, 3-trifluoropropyl.
¦ Again, if the platinum catalyst is not incorporated in the hydride j polysiloxane or the hydride silicone resin or in the emulsion of the ¦ hydride silicone resin, then the R2 radical can also be ~elected frt)m ~,l 60SI- 176 112153Z EPKI meo l !
aliphatically unsaturated radicals such as, vinyl, ally~, etc. Pre-ferably, the R2 radical in the hydride silicone resins as well as in the hydrogen polysiloxane of Formula 2 is selected from methyl, , ethyl and phenyl.
The hydride silicone resin cross-linking agents are obtained by hydrolysis procedure. Such procedure comprises taking, for ¦
instance, a hydrogen diorganochlorosilane and tetrachlorosilane and hydrolyzing it in water with or without an organic solvent present.
The resultant silicone resinous structure that is formed is then ¦
separated and purified by well known techniques. Thus, the resin may be washed with water so as to remove as much acid from the ¦
resin as possible, and finally the silicone resin can be neutralized or approxi~ately neutralized to an acidity of less than 15 parts per million of acid with a mild base such as, sodium bicarbonate. The resulting hydride silicone resin can then be utilized as a cross-linking agent in SiH-olefin platinum catalyzed compositions. The procedure for producing the hydride silicone resin, also containing hydrogen organo difunctional siloxy units is similar to that above for the more simple resin, the only diff erence being that there is utilized as a reactant a hydrogen organodichlorosilane. Irrespective of which hydrolysis technique is used, that is, one with a water immiscible organic solvent or one without a water immiscible organic solvent, there would be obtained to some degree the hydride silicone l j resins disclosed above, which resins can be utilized as a cross-linking agent in the invention of the instant case. The polysiloxane of Formula 2 above is preferred over the hydride silicone resins as i i 11~1532 EPKI meo a cross-linking agent since it is easier to emulsify and reacts much faster to produce the paper release coating. The hydride silicone resins are preferred in that they give more abrasion resistant I' coatings when they are utilized as cross-linking agents for the vinyl-, 1i containing polymer of Formula 1.
I¦ It should be noted that the vinyl-containing fluid of Formula 1 of ¦l the instant case can be cured either with a hydride polysiloxane of l ¦
Formula 2 above or can be cured with a hyd~ide silicone resin l! composed only of monofunctional siloxy units and tetrafunctional ¦ siloxy units or can be cured with a hydride silicone resin composed of monofunctional siloxy units, tetrafunctional siloxy units and difunctional siloxy units. Irrespecti~e o the.hydride cross-linking agent tha~ is utilized, the vinyl-containing polymer of Formula 1, would cure to forrn a good silicone paper release coating. The only difference in the selection of hydride cross-linking agents being in the rate of cure and also in the abrasion resistance of the cure that ¦ is obtained depending on what type of hydride cross-linking agent ¦¦ was used. Hydride silicone resins as was the case for the hydride ¦ polysiloxane of Formula 2, are also emulsified prior to their being ZO ~ rnixed into the emulsion of the polymer of Fo~rnula 1. ¦
As an exam.ple, such an emulsion is prepared by taking anywhere I from 10 to 20% by weight of the hydride silicone resin or 10-20%
¦ of the compound of Forrnula 1, 5-10% by weight of the allcylphenoxy-¦ polyoxyethyleneethanols, . 04~o by weight of acetic acid as a bacteri-2~i cide, 4. 6% of the first quantity of water and 50-70% of a second quantity of water, and .1% of Formalin, that is, a solution of ¦ formaldehyde as a bactericide. It should be noted that as indicated Il above that some of the vinyl-containing polymer of Formula l rnay be incorporated into the emulsion of the hydride polysiloxane silicone resin or the hydrogen polysiloxane emulsion of Formula 2 above, Il that is, some of the vinyl-containing polymer of Formula 1 can be ' incorporated and emulsified with the hydrogen polysiloxane cross-ii linking agent so long as the platinum catalyst is not also present in the same emulsion. As long as the platinum catalyst is not in the same emulsion, then the hydride polysiloxane will not cross-link with I the vinyl-containing pol~mer of l~orrnula 1 to form a cured silicone ¦ coating.
Accordingly, so as to facilitate the mixing of the two emulsions ¦
together, that is, to facilitate the mixing of the hydride polysiloxane I I
emulsion with the vinyl-containing emulsion of Formula 1 so that there w;ll be more quantity of hydride polysiloxane emulsion to work ¦! with some of the vinyl-containing polymer of Formula l may be incorporated and utiliæed in forming the emulsion of the hydride polysiloxane of Formula Z or the hydride polysiloxane silicone 1 ' resins.
¦¦ Accordingly, to prepare the emulsion of the hydride silicone resin ¦¦ there is charged into a premixing kettle the hydride resin and the ¦I vinyl-containing polymer of Forrnula l. The acetic acid and the first j quantity of emulsifying agent is added and the mixture is heated for 30 minutes with slow agitation at 35C. Then the first quantity of water is added at a sufficient rate so as to prevent inversion and the temperature of the mixture is maintained at 35C, and agitation is continued for 30 minutes after the addition of water. Then the second ~ I
quanti of wate:^, acetic acid and formaldehyde is added to the blend .: I . I

11;~1532 60SI- l 76 EPK/ meo and the agitation continuing with the temperature control maintained at 25 to 3GC before passing it through the colloidal mill. The a~Eluent paste on the mill is directed to the blend containing the second quanti~y of water. After the milling is completed the emulsion can I then be stirred for a minimum of 45 minutes at 25 - 30C. Stirring ~
is continued and the temperatures maintained at the above level until j all of the paste has dissolved into the water. Af~er that the emulsion i is allowed to stand for a minimum of 30 minutes and there results the final hydride silicone resin emulsion for use as a cross-linking ~0 I agent with the emulsion of the vinyl-containing polymer of Formula l Accordingly, utilizing the above procedures, there is obtained emulsions of the hydride cross-linking agent and of the base polymer ', of Formula 1 which emulsions can be mixed and applied and cured on paper to form silicone paper release coatings with known techniques f ¦~ and procedures as well as wi~h present equipment u~ilized in paper I release coating plants.
i :E?inally, when it is desired to have a system that is cured by tin, it is ¦ necessary to e~nulsify the tin soap by itself so as to have a three l li i component system, that is, the emulsion of the vinyl-containing polymer I of Formula l, the emulsion of the hydride polysiloxane of Formula 2, or an emulsion of one of the hydride silicone resins as disclosed previously and thirdly, an emulsion of the tin soap. When a tin I catalyst system is being utilized, the three emulsion components are simp1r ~ixed and applied by k~ ~ techniques to coat paper. The ti~

i~ 60SI-176 11~1532 EPK/m.eo salt of a carboxylic acid can be utilized in the instant case. The most preferred tin soap is dibutyl tin dilaurate since * is readily avail-¦' able, inexpensive and is a very efficient tin catalyst. '~
¦', It should be noted that when the tin catalyst or tin system is utilized ,~l~ then the concentration of the tin catalyst must be in the range of . 1 to ,!1 2 parts by weigh~ of a tin salt of a carboxylic acid. The. above ~i concentrations being given in terms of tin metal, per 100 parts of the vinyl-containing polymer of Formula 1. More preferably, the an~ount of tin catalyst that is utilized is a concentration of . 5 to 1. 5 parts of . ¦ tin catalyst as tin, per 100 parts of the vinyl-containing polymer of. ~ Formula 1.
It should also be noted that the presen~ tin system. can either cure at ~ room temperature or cure at elevated temperatures, that is, it has i a prolonged shelf life at room temperature but cures very rapidly at ~ elevated temperatures. To accomplish this with a tin systerr~ it is common to use a mercapto tin salt of a carboxylic acid as the catalyst since such a mercapto tin salt of a carboxylic acid will cure the system very slowly at room temperature but will initiate the cure of the ¦
system at a very rapid rate at elevated tem.peratures, that is, temperature s above 300 F.
Accordingly, a good exa~nple of a rnercapto tin salt of a carboxylic ¦ acid which gives extended work life to the emulsion mixtures of the ¦ instant case, that is, the three component tin system of the instant ¦ case, and yet cures the system at a very rapid rate at elevated ~25 ¦ temperatures is di(N-octyl) tin S, S'-bis(isooctylmercaptoacetate). It 60SI- 176 1 ~
~l~ZlS3Z EPK/ meo , should be noted the same ef~ect can be carried out with the platinum catalyzed system. when it is desired, by simply incorporating an inhibitor in the platinum system such that the system. would have a long 1~ shelf work life at room temperature after the hydride siloxane cross- ' 1. linking agent is mixed with the polysiloxane of Formula l, but will cure at a very rapid rate at elevated temperatures. Examples of j ¦ inhibitors for platinum catalyzed systems that will give them such ! platinum catalyzed system.s extended work life at room temperatur e ¦ but very quick curirlg at elevated temperatures, is, for instance, I acetylenic compounds, hydroperoxy compounds and m.ethylvinylcyclo-! tetrasiloxanes ¦l It should be noted that the m.ethylvinylcyclotetrasiloxanes are mild ¦¦ inhibitors to inhibit 'che platinum catalyzed compositions at room li temperature for 10-20 minutes but allow cure of the system af~er that.
1I However, the systeIn even with any of these inhibitors in it, that is, the platinum catalyzed system with any of these inhibitors, will cure ' in a matter of minutes or even seconds upon being heated at tempera- ¦
tures above 100C. It should also be noted the hydrogen content of the hydride silicone resin, that is, the hydride silicone resins co~nposed of monofunctional siloxy units and tetraunctional siloxy units, may vary anywhere from . 3 to 1. 6% by weight and the hydride content of the ¦ 11 silicone resin composed of monofunctional siloxy units, tetrafunctional I li ~ siloxy units and diunctional siloxy units may ~rary anywhere from. . 3 to ¦ 1. 6% by weight and still f~mction as an effecti~re crcss-linking agent.

11;~1532 EPK/ meo i With respect to the tin salt of a carboxylic acid, this can be emulsified with polyvinyl alcohol such that there can be utilized as ¦, an example frorn 20% by weight of the tin salt of a carboxylic acid such as, dibutyl tin dilaurate, 1. S to 2% of polyvinyl alcohol, and ~l arOt?natic solvent such as, xylene, mineral spirits and polych~orinated solvents up to 30% by weight, glycerin and other non-ionic ¦
emulsifiers can be used up to 2% and then the mixture passed through ' a colloidal mill and adjusted to the appropriate solids with water.
The resulting emulsion of the tin salt may then be used in a three component tin system of the instant case to prepare a paper release ¦
11 coating emulsion composi~ion.
¦¦ The emulsion of the compound of Formula l, not containing the !I platinum catalyst, can be combined with an emulsion of a hydride cross-linking agent which is prepared as indicated previously and It which can be combined with the e~nulsion of the tin salt to prepare I i the emulsion mixture which can then be applied over paper and dried to prepare a paper release coating. The paper release coating can be prepared either at room temperature or at elevated temperatures in accordance with the use of the mercapto tin salt versus the straight ~20 ~ tin salt itself. Irrespective of which system is used, as is evident ¦from the above disclosure, by simply utilizing the vinyl-containing I compound of Formula l above an emulsion of such a compound can be ¦
¦~ cured and applied as a paper release coating either with a platinum ~j system as disclosed above or with a tin system as also disclosed J
above.

ll - 28 -'I

1~ 32 EPK/ rneo The examples below are given for the purpose of illustrating the !¦ present invention. They are not given for any purpose of setting i~ definitions to the scope of the invention of the instant case. All ~parts in the examples are by weight.

¦,EXA.MPLE

I There was prepared an emulsion ~Composition A) comprising a ¦ mixture of 50 parts by weight of a silanol-terminated methylvinyl- , polysiloxane polymer having the viscosity of 2900 centipoise at 25~C. ¦
I To this there was added 15. 9 parts of polyvinyl alcohol, . 04 parts of I sorbic acid, . 20 parts of sodium benzoate, . 04 parts of platinum ¦
I catalyst (as Lamoreaux catalyst as disclosed in the foregoing patent), 8. 56 parts of a first quantity of water, 25.16 parts of a second quantity o water and . 001 parts of formaldehyde. The emulsion was prepared by charging the vinyl fluid and the platinum ~ ;
, catal~st to the premi~ tank. Then there was slowly added to the , mixture, the polyvinyl alcohol and mixing was continued at moderate agitation speed for 20 - 30 minutes. After this, there was slowly j added the first quantity of water, that is, the 8. 56 parts of water ¦ while agitation was continui~g. The rate of addition and agitation was I su~iciently slow to avoid inversion. Then there was continued ', ¦¦ agitation at moderate speeds for 30 minutes. Then there was charged to the mixture the second quantity of water, that is, 25. lo parts of water, and the various bactericides, sorbic acid and sodium benzoate. The resulting mixtures were then milled through a i 1, ~
~ ~1 !
' i 53;~ EPK/ meo .
j,~ Manton-Gaulin colloid mill at high speed using a three-inch rotor and stator and a clearance of 5 - 12 mils. The resulting paste that was 1, obtained was then blended with water at slow speed agitation for Z0 -j, 30 minutes, after the milling was complete. The milled paste was blended in the larger quantity of water and dispersed to form the desired emulsion at 50% silicone solids.
i There was prepared an emulsion ~Composition B) comprising a rnixture ' ¦ of 20 parts by weight of a ~rinyl-terminated methylvinylpolysiloxane ¦ polymer and 20 parts by weight of a resin composed of dimethyl ¦ hydrogen siloxy units, SiO2 units having a viscosity of 600 centipoise j at 25C. To this there was added 5, 2 parts of alkylphenoxypoly-¦ ethoxyethanol (nonionic emulsifier), 4. 6 parts of a first quantity of ¦ water, 50. 66 parts of a second quantity of water, 0.1 parts of Formalin and 0. 04 parts of acetic acid. The emulsion was prepared by charging ! the vinyl fluid and the dimethyl hydrogen resin to the premix vessel.
Next, the alkylphenoxypolyethoxyethanol emulsifiers were blended in the oils. Then there was slowly added the first quantity of water and mixing was continued at 35C uYlder moderate agitation speed for 20 -¦ 30 minutes. The rate of water addition and agitation was sufficiently ¦ slow to avoid inversion. Then there was continued agitation at moderate speed for 30 minutes. To a blend vessel there was added the second I part of water, Formalin, bactericide and acetic acid. The emulsifier, ¦, oil and part one of the water was then milled through a Manton-Gaulin I colloid mill at high speed using three-inch rotor and stator and a I clearance of 5 - 12 mils. The resultant paste that was obtained was I blended with the part two water, bactericide and acetic acid blend ¦1 !
i , - 30 -I I

llZ153Z EPK/ meo contained in the blend vessel. The resultant emulsion was measured , to be 40% silicone solids.
¦ There was then prepared a mixture of the emulsions of the vinyl fluid ¦; as indicated above and of the hydride silicone resins which emulsions I were prepared as indicated above. Accordingly, there was mixed 16 ~ parts of the vinyl fluid emulsion with 1. 6 parts of the hydride silicone j resin emulsion to which ~,vas added 50 parts of water wh ch contained 1% of sodium algenate, a ~.vat er thixotropic, and to this there was ¦
I added additional amounts of 32. 4 parts of water. The above formulatio~
~ was coated on Riegel ~42 bleached Kraft paper at 15 lbs. per ream.
i ~he release value of such a coating, as measured on an Insatron Machine whose jaws open at a rate of 12 inches per minute, was 10 -~! 25 grams per inch. A good value for release of pressure sensitive adhesives. It was also observed in the foregoing test with the above ¦ composition that there was no smear or rub-off when the sa}nples ¦
weretested.
Then there was carried out a Subsequent Adhesion Test. The Subse-¦ quen~ Adhesion Test requires the taking of pressure sens*ive adhesive, ¦ tape which had been stuck to the paper release coated paper and I stripping it from the paper and applying it to a c:lean steel panel. To I the same steel panel there is applied a pressure sensitive adhesive ¦l tape which was not adhered to any paper release coating~ Then the panels were aged for 20 hours at 25C. Rubber weights of 7. 8 lbs. I
I were applîed over the pressure sensitive adhesive tapes stuck to the ~I steel panel. After that the tapes were aged for 1 ho~r at 50% relative, ~, humidity and at 77F, and the pressure sensitive adhesive tapes were I

,1 .

~i - 31 -llZ153Z 6051- 176 pulled from the steel panel and the amount of force necessary to pull from the panel was determined. Then there was determined the Subsequent Adhesion Values, that is, the diference between the initial adhesion of the tape that was not stuck to any paper release coating and the adhesion value for the tape that was stuck to a paper release coating prior to being s tuck to the aluminum panel, and the amount of the di~ference is calculated and divided by the adhesive ¦
value for the pressure sensitive adhesive panel that was not stuck to any paper release coating and the dividend is multiplied by 100.
This gives ~he percentage value of how much the adhesion of the pre- ~ i stuck panel to a paper release coating differ from an adhesive panel which had not been adhered to any paper release coating. This test gives a quantative value or the amount of the cure of the paper release coating. The higher the cure of the paper release coating the less of it will become adhered to the pressure sensitive adhesive panel and thus the higher will be or closer will be the proximity of the pressure sensitive adhes~e panel to the control in terms of forcing it to separate from the steel panel. Utilizing the above test, there was obtained a value for subsequent adhesion of between 90 and ¦
100% with the above composition, indicating that the composition had cured almost completely.

- .

There was taken the ~inyl fluid emulsion of Example 1 and it was cured with two systems in accordance wi~h the ollowing.

~, 1 $32 EPK/ meo ~

There was prepared an emulsion (Composition C) comprising a mixture of 50 parts by weight of a trimethylsiloxane terminated methyl hydrogen polysiloxane polymer having a ~iscosity of greater than lOûO centipoise at 25C. To this there was added 5. 75 parts of aLlcyl-phenoxypolyethoxyethanol (nonionic emulsifier), 5. 75 parts of a first quantity of water, 0. l parts of ~ormalin and 38. 4 parts of a second quantity of water. The emulsion was prepared by charging the methyl hydrogen polysiloxane oil to the premix vessel. Next the j ethanol emulsifier is charged to the ~ressel and blended at 35 - 40C for half an hour under moderate agitation speed. Then there was added s lowly the first quantity of water, mixing was continued at 35 - 40C
under moderate agitation. Once all the first part of water was added the premix was blended an additional hour. The rate of water addition ¦
and agitation was sufficiently slow to avoid inversion. While the pre-mix was being blended, the second part of water and Formalin (bactericide) was charged to a blend vessel, which was to be used to collect paste and blend same. The emulsifier, oil and part one water (premi~) was then milled through a Manton-Gaulin colloid mill at high speed using two-inch rotor and stator and a clearance of 5 mils. The resultant paste that was obtained was blended with the part two water and bactericide in the blend vessel. The resultant emulsion was measured to be 40% silicone solids.
There was prepared a catalyst emulsion (Composition D) comprising a mixture of 33. 3 parts by weight dibutyl tin d;laurate. To this there wa added S parts odorle=s mineral spirit3, 15 parts ~f a 10% poly-3 3 _ i i' ~

j 60SI-176, EPK/ med llZ3 S32 1, vinyl alcohol solution and 46. 7 parts water. The emulsion was pre- s pared by charging the dibutyl tin dilaurate to the premix vessel.
Next the odorless mineral spirits were charged and the vessel was ," stirred with moderate agitation to dispense the dibutyl tin dilaurate. i -The polyvinyl alcohol solution was added and the tin soap solution was i blended for another half hour under moderate agitation. Then there was~ slowly added, the water, and the mixing was continued under moslerate agitation for an additional half hour after all the water was charged. The rate of water addition and agitation was sufficiently I slow to avoid preimersion. The emulsifier, tin soap, mineral spirits s and water were then milled through a Manton-Gaulin colloid mill at high speed using three-inch rotor and stator and a clearance of 5 - ¦
10 mils. The resultant emulsion obtained was then filtered through I cheese cloth prior to measuring the solids. The resultant emulsion ~ was measured to be 35% total solids.
To 16 parts of the emulsion of the vinyl fluid of Example 1 there was j mixed . 8 parts of Composition C with . 8 parts of Compos*ion D. To these emulsions there was added 50 parts of water thickened with 1%
I of sodium algenate, a thixotrope. To the resulting mixture there was ¦
! added an additional amount of 32. 4 parts of water. The resulting forInulation when applied as a paper coating cured to give a release , value at the Insatron Machine opening at the rate of 12 inches per minute of 2Q - 40 grams per inch. Al~hough this value was a little high, it was, nevertheless, a still acceptable paper release -~alue for ¦
i paper release coatings ;n the ind~stry. The above formulation also j i ¦, 60SI-17 EPK/ meo S37~ ' I' ~
j~ required l to 2 hours post-bake cure at room temperature at 50%
!~ relative humidity.
It should be noted that the samples in the present Example were also superior as paper release coatings as were the samples of Example l, in that the samples show no smear Ol rub off thus indicating that the coating had good abrasion resistance. It was also felt that the paper , release values and adhesion ~alues could be lowered by increasing the ¦ post-bake cure period or by increasing the amount of tin catalyst.
¦ In any case, the vinyl fluid of Example 1 was cured with both a ¦ plat~num system and tin system to yield a good paper release coating 1 in each instance, as the data above indicates.
ll I
¦I EXAMPLE 3 There was taken a vinyl fluid emulsion of Example l that was cured I with the methyl hydrogen emulsion of Example 2, and another emulsion ~ catalyst in accordance with the following.
There was prepared a Composition E, comprising a mixture of 20 ¦ parts by weight of di-(N-octyl)tin-S, S'-bis-(isooctyl mercapto acetate).
To this tin soap there was added 20 parts of 10% polyvinyl alcohol ~ solution, 0.1 parts of 6-acetoxy-2, 4-dimethyl-m-dioxane (bactericide)"
I 0. 25 parts sodium lauxylsulfate, 10 parts of a first quantity of water, ¦ and 49. 65 parts of a second quantity of water. The emulsion was pre-¦ pared charging the mercapto tin soap, polyvinyl alcohol solution and ba-tericide to the premi~ vessel and ag*ating 30 - 40 ~3inutes at Ii 1,, ~Z153~ 60SI- 1 76 30 + 5C using moderate agitation speed. Next, the first quantity of water with the sodium laurylsulfate predissolved in the water was added to the premix vessel. Once the first quantity of water con- ~
¦i taining the dissolved sodium laurylsulfate had been added the agitation I
¦ of the premix was continue~ for 60 + 25 minutes. The rate of water addition and agitation was sufficiently slow to avoid preinversion of ¦ the premix. To a blend vessel there was added the second quantity I
¦ of water. The premix containing emulsifier, tin soap, bactericide, l I
I and water was then milled through a Manton-Gaulin colloid mill at ~i ¦ high speed using fhree-inch rotor and stator and a clearance of 3-5 mils. The resultant paste that was obtained was blended with the second quanti~r of water contained in the blend vessel. The paste and water were agitated until uniform. Then the resultant blend was I measured to be 22% total solids.

I E~AMPLE 4 l ll , There was then prepared a mixture of emulsion of the vinyl fluid (Example 1, Composition A) and of the methyl hydrogen polysiloxane fluid which emulsion was prepared as indicated in Example 2, Composition C. Accordingly, there was mixed 16 parts of the vinyl 2~ I fluid emulsion with 4 parts of the methyl hydrogen polysiloxane fluid¦ emulsion to which was added 54 parts of water which contained 1%
I sodium algenate, a water thixotrope, and to this there was added 3. 2 I parts of mercapto tin catalyst emulsion ~Co~npos ition E) and ¦~ additional amounts of 22. 8 parts c,f water. The above formulation l' l .~ I
! . I

11~3L53Z 60SI- 176 ~, was coated on Riegel 7~42 bleached Kraft paper at 0. 5 lbs. per 3000 ' sq. foot ream. The release values of such a coating as measured on an Insatron Machine, ~vhose jaws open at a rate of 12 inches per ~ minute, was 8 - 1~ grams per inch, a good value for release of I pressure sensi~ive adhesives It was also observed in the foregoi.g test with the above composition that there was no smear or rub-off ¦ when the coated paper samples were tested. Laminated samples which contained release coated paper, pressure sensiti~e adhesive and I vinyl sheeting were cut in 11' x 6" strips. These test strips were aged two weeks in a 70C air circulating oven with a one kilogram ¦
(l" x l" x 6") steel weight upon the sarI~ples. The samples were renlo~red from the oven and were conditioned for 1 hour at 50% relative i humidity and at 771?. The pressure sensitive adhesive tapes were I pulled on the Insatron Machine at a rate of 12 per minute. The force 15 ~ necessary to delaminate the test sample was measured to be 38-65 ¦l grams per inch, a good value for aged release of pressure sensitive a dhe siv:: .

, . ~ ~ .
.

Claims (26)

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

1. A paper release coating emulsion composition comprising (A) 100 parts by weight of a vinyl-containing polymer of the formula, where Vi is vinyl, R is an aliphatically saturated monovalent hydrocarbon radical, R' is a monovalent hydrocarbon radical and x and y vary such that the polymer has a viscosity ranging from 1,500 to 24,000 centipoise at 25°C. in which the polymer has a silanol content that varies from 650 to 2,400 parts per million and a vinyl content that varies from 0.1 to 2% by weight;
(B) from 1 part per million to 2 parts by weight of a catalyst selected from the class consisting of platinum catalyst and tin soaps of carboxylic acids; (C) from 1 to 30 parts by weight of a hydride polysiloxane crosslinking agent; (D) from 50 to 300 parts of water, and (E) from 5 to 80 parts by weight of emulsifying agents.

2. The composition of claim 1 wherein the catalyst is a platinum catalyst at a concentration of 1 to 200 parts per million.

3. The composition of claim 2 wherein the platinum catalyst is platinum complexed with hydrocarbon compounds selected from the class consisting of alcohols, aldehydes and ethers.

4. The composition of claim 2 wherein the platinum catalyst is platinum complexed with a vinyl siloxane wherein the platinum complex is substantially free of chemically combined chlorine.

5. The composition of claim 1 wherein the hydride polysiloxane has the formula, where R2 is selected from hydrogen and monovalent hydrocarbon radicals and s, t vary such that the viscosity of the polymer varies from 1 to 250 centipoise at 25°C.

6. The composition of claim 5 wherein the polymer has a viscosity of 5 - 50 centipoise at 25°C, and a hydride content varying from 0.3 to 1.6% by weight.

7. The composition of claim 1 wherein the hydride polysiloxane is composed of H(R2)2SiO0.5 units and SiO2 units, where the H + R to Si ratio varies from 1.0 to 2.7 and R2 is a monovalent hydrocarbon radical.

8. The composition of claim 1 wherein the hydride polysiloxane is composed of H(R2)2SiO0.5 units, SiO2 units, and H(R2)SiO units where the ratio of R2 + H to Si varies from 1.0 to 2.7 and R2 is a monovalent hydrocarbon radical.

9. The composition of claim 1 wherein the emulsifying agent is polyvinyl alcohol.

10. The composition of claim 1 wherein the hydride polysiloxane is first emulsified before it is added to the mixture.

11. The composition of claim 10 wherein the hydride polysiloxane is first emulsified in water and as the emulsifying agent an alkylphenoxypolyoxyethyleneethanol where the alkyl group has from 1 to 15 carbon atoms.

12. The composition of claim 1 wherein the catalyst is a tin soap of a carboxylic acid and is dibutyl tin tilaurate and is present at a concentration of 0.1 to 20 parts by weight as tin.

13. The composition of claim 1 wherein the catalyst is a mercapto tin soap of a carboxylic acid and is di(N-octyl)tin S,S'-bis(iso-octylmercaptoacetate) and is present at a concentration of 0.1 to 2 parts by weight as tin.

14. A process for forming a silicone paper coating comprising (1) emulsifying a mixture of (A) 100 parts by weight of a vinyl-containing polymer of the formula, where Vi is vinyl, R is an aliphatically saturated monovalent hydrocarbon radical, R' is a monovalent hydrocarbon radical and x, y vary such that the polymer has a viscosity varying from 1,500 to 24,000 centipoise at 25°C. in which the polymer has a silanol content that varies from 650 to 2,400 parts per million and a vinyl content that varies from 0.1 to 2% by weight; (B) from 1 part per million to 2 parts by weight of a catalyst selected from the class consisting of platinum catalysts and tin soaps of carboxylic acids; (C) from 50 to 300 parts of water; and (D) from 5 to 80 parts by weight of emulsifying agents, (2) emulsifying a hydride polysiloxane;
(3) adding the emulsion of the hydride polysiloxane to the emulsion of the vinyl-containing polymer such that there is present from 1 to 30 parts by weight of the hydride polysiloxane per 100 parts of the vinyl-containing polymer;
and (4) allowing the composition to cure.

15. The process of claim 14 wherein the catalyst is a platinum catalyst at a concentration of 1 to 200 parts per million.

16. The process of claim 15 wherein the platinum catalyst is a platinum complexed with a hydrocarbon compound selected from the class consisting of alcohols, aldehydes and ethers.

17. The process of claim 15 wherein the platinum catalyst is platinum complexed with a vinyl siloxane wherein the platinum complex is substantially free of chemically combined chlorine.

18. The process of claim 14 wherein the hydride polysiloxane has the formula, where R2 is selected from hydrogen and monovalent hydrocarbon radicals, and s, t vary such that the viscosity of the polymer varies from 1 to 250 centipoise at 25°C.

19. The process of claim 18 wherein the hydride polysiloxane has a viscosity of 5 - 50 centipoise at 25°C, and a hydride content varying from 0.3 to 1.6% by weight.

20. The process of claim 14 wherein the hydride polysiloxane is composed of H(R2)2SiO0.5 units and SiO2 units where the R + H to Si ratio varies from 1.0 to 2.7 and R2 is a monovalent hydrocarbon radical.

21. The process of claim 14 wherein the hydride polysiloxane is composed of H(R2)2SiO0.5 units, SiO2 units, and H(R2)SiO units where the ratio of R + H to Si varies from 1.0 to 2.7 and R2 is a monovalent hydrocarbon radical.

22. The process of claim 14 wherein the emulsifying agent is polyvinyl alcohol.

23. The process of claim 14 wherein the hydride polysiloxane is emulsified in water and as the emulsifying agent there is used an alkylphenoxypolyoxyethyleneethanol where the alkyl group has from 1 to 15 carbon atoms.

24. The process of claim 14 wherein the catalyst is a tin soap of a carboxylic acid and is dibutyl tin dilaurate and is present at a concentration of 0.1 to 2 parts by weight as tin.

25. The process of claim 14 wherein the catalyst is a mercapto tin soap of a carboxylic acid and is di(N-octyl)-tin S,S'-bis-(isooctylmercaptoacetate) and is present at a concentration of 0.1 to 2 parts by weight as tin.

26. A process for coating paper with a silicone paper release coating with excellent release properties to pressure sensitive adhesives comprising (1) emulsifying a mixture of (A) 100 parts by weight of a vinyl-containing polymer of the formula, where Vi is vinyl, R is aliphatically saturated monovalent hydrocarbon radical, R' is a monovalent hydrocarbon radical and x, y vary such that the polymer has a viscosity varying from 1500 to 24,000 centipoise at 25°C; (B) from 1 part per million to 2 parts by weight of a catalyst selected from the class consisting of platinum catalysts and tin soaps of carboxylic acids; (C) from 50 to 300 parts of water; and (D) from 5 to 80 parts by weight of emulsifying agents; (2) emulsifying a hydride polysiloxane; (3) adding the emulsion of the hydride polysiloxane to the emulsion of the vinyl-containing polymer such that there is present from 1 to 30 parts by weight of the hydride poly-siloxane for 100 parts of the vinyl-containing polymer to form an emulsion mixture; (4) applying the emulsion mixture to paper; and (5) allowing the foregoing emulsion mixture to cure.