CA1246270A - Water based resin emulsions - Google Patents

Abstract

WATER BASED RESIN EMULSIONS
ABSTRACT OF THE DISCLOSURE

Water-based silicone resin emulsions are provided comprising an organopolysiloxane resin or mixture of resins which may include a solvent carrier, and a combination of emulsifying agents including hydroxylated or neutralized carboxylated vinyl addition polymer-type and anionic or nonionic surfactant-type emulsifiers as well as an amount of water sufficient for providing a water-based emulsion having a desired viscosity and silicone resin solids content by weight.

Description

12~6Z7~) ~ATER BASED RESIN EMULSION5 BACKGROUND OF T~E INVENTION
This invention relates to water-based emulsions of organopolysiloxane resins which are useful in coating applications where aqueous emulsions are preferable over traditional organic solvent based systems. The present invention provides both water-ba~ed silicone emulsions as well as methods for producing such compositions.
Silicone resins are often selected for applications requiring premium properties. These organopolysiloxane resins are known to offer outstanding endurance to environmental conditions æuch as weathering and extreme heat and cold. Silicone resins have found utility in a variety of applications such as pressure sensitive adhesives and release coatings. Furthermore, they have heen found to be particuarly useful in the paint industry which is continually seeking coating formulations which offer premium properties. Silicone 2a resin solutions have previously been used in the paint coatings industry as vehicles and binders which are a necessary paxt of quality paint formulations.
Heretofore silicone resins were ordinarily supplied to formulators in solutions, that is to say, the resin consisted of so many parts by weight of silicone solids in some organic solvent such as xylene or toluene. However, recently the use of such organic solvents has ~een discouraged due to escalating costs for organic materials and increased concern for ~2~6'~70 environmental considerations. Organic solvent based silicone resins often required the use of costly and cumbersome pollution abatement procedures and equip-ment. Thus there has been a trend in recent years for silicone resin systems which are water-based and therefore not dependent upon organic solvents.
However, such silicone resins which have been found to have particular utility in the art of paints and other coatings have often been immiscible or otherwise incompatible with aqueous coating systems.
The present inyention provides for the first time silicone resins which can be readily dispersed into water-based emulsion compositions thereby providing the beneficial properties of silicone resins without the cumbersome necessity of unduly large amounts of organic solvents.
As noted above, silicone resins are intended as high performance coating vehicles which can ~e used in high temperature-resistant coatings and will generally outperform conyentional organic resins in similar applications. Those skilled in the art will recognize that there are a number of silicone resins which can be utilized in coating applications. Those silicone resins proYided in U.S. Patents 4,Q28,339, issued ~une 7, 1977 25 and 4,a56,492, issued November 1, 1977, both issued to Merrill, are examples of resins which can be made part of the water-based emulsion compositions of the present invention.
Previously known silicone resin emulsions have 3Q ~een succesfully utilized in coating glass fabric, however, such compositions require the use of nonionic emulsifiers, such as alkylphenoxy polyethoxyethanol.
In such a system there is generally required approximately one part e~ulsifier for each nine parts of resin solids.
When this type of emulsion technology is attempted in conjunction with the resin coating formulations 12~627(~

discussed herein, as required by paint formulators, residual emulsifier is entrained in the coating and has a significant deleterious effect on such coatings at elevated temperatures. Also known are silicone resin emulsions based on a combination of nonionic and anionic emulsifiers and these can include "acid thickeners based on a carboxyvinyl polymer of high molecular weight"
see, e.g., U.S. Patent 4,052,331, issued October 1, 1977 to Dumoulin, Col. 6, line 58. Also disclosed are composi-tions containing small amounts of polyvinyl alcohol, of rather high saponification number. Such compositions can be formulated into sun-screens, for example, for applications to human skin, but acid thickeners might not be well tolerated. Use as coatings for unbleached kraft paper is also disclosed.
The present invention, on the other hand, utilizes an emulsion system based upon a combination of nonionic and/or anionic surfactants and certain vinyl addition polymeric emulsification agents having pendent hydroxyl groups or pendent neutralized carboxyl groups or mixtures of such groups. The total emulsifier requirement for the emulsions of the present invention is generally in the range of approximately 0.5 to 50.0 percent based upon the weight of the silicone resin solids. Additionally, it seems that the use of vinyl addition polymer emulsification agents having pendent hydroxyl groups or pendent neutralized carboxyl groups or mixtures of such groups as co-agents enables the water-based compositions to coat out more uniformly as compared to the above-described emulsions utilizing nonionic emulsifiers, which tend to produce "fish-eyes" in the film.
It is therefore a primary object of the present inven-tion to provide water-based emulsions of organopolysiloxane resins which are useful in coating compositions.
It is another object to provide an emulsifier system comprising a combination of nonionic and/or anionic surfactant and polymeric emulsification agent having pendent hydroxyl groups or pendent neutralized carboxyl groups or mixtures of such groups which are effective for dispersing silicone resins in a water-based coating system.
It is another object to provide a process for producing water-based silicon resin emulsions.
These and other objects will become apparent to those skilled in the art upon consideration of the accompanying description and claims.
SUMMARY OF THE INVENTION
The water-based silicone emulsions of the present invention are comprised of (a) 100 parts by weight of at least one organopolysiloxane resin composition consisting approximately of zero to 50 percent by weight of mono-functional units having the general formula R3SiOo 5~ zero to 60 percent by weight difunctional units of the formula R2SiO, zero to 100 percent by weight trifunctional units having the general formula RSiOl 5, and zero to 60 percent by weight tetrafunctional units having the general formula SiO2. In the above formulae R represents a substituted or unsubstituted monovalent hydrocarbon radical which will ordinarily be selected from the group consisting of, independently, methyl and phenyl radicals. The organo-polysiloxane resins utilized in the present invention will ordinarily have an R to Si ratio of, approximately, 1.0 to 1.99 R groups for each silicon atom. It is to be under-stood that the present invention contemplates the use of blends of different organopolysiloxane resins in the present emulsions as well as the use of a single type resin for each emulsion.
A more particular example of organopolysiloxane resins which are useful in the emulsions of the present inventions are those comprised of, approximately, 5 to 40 percent by weight CH3SiO1 5 units, zero to 35 percent (CH3)2SiO units, 15 to 65 percent (C6H5)SiO1 5 units, and zero to 50 percent (C6H5)2SiO units, wherein there is present, approximately, 1~6270 - 5 ~ 60SI 409 1.0 to 1.8 organic radicals for each silicon atom.
It is to be noted that -these organopolysiloxane resins can be emulsified in water through the process described in the present invention. However, it is common in the art of silicone resins that such resins be provided in solutions consisting of some specified weight percent silicone resin solids based upon the weight of said silicone solids and the solvent. For example, the silicone resin may be provided as an approximately 20 to 90 percent by weight silicone resin solution in an organic solvent as toluene or xylene. It is to be noted that this organic solvent, if present, is not a critical component of the present invention nor does it ordinarily detract in any way from the useful properties of these water-based silicone emulsions. Indeed, often the presence of small amounts of organic solvents in such emulsions impart otherwise beneficial properties to such emulsions.
The water-based emulsions of the above-described silicone resins are provided by utilizing a combination of emulsifying agents. The amount of emulsifying agents required to emulsify each 100 parts by weight resin solids will vary widely depending upon process conditions and the selection of the remaining constituent ingredients of the emulsion. Those skilled in the art will be able to produce a variety of water-based silicone resin emulsions according to the method set forth herein, and will be able to ad~ust the amount of emulsifying agents according to individual desires. Without intending to limit the scope of the present invention in any way, it will ordinarily be the case that, approximately, 0.25 to 50 parts by weight of the combination of emulsifying agents will be necessary to produce the water-based silicone resin emulsions of the present invention. It has been discovered by the present invention that a particular combination of 12~6Z70 60SI-409 emulsifying agents is effective for dispersing these silicone resins and thereby providing water-based emulsions. The combination of emulsifying agents is comprised of 5 to 95 percent by weight of an emulsification agent comprising a vinyl addition polymer having pendent hydroxyl groups or pendent neutralized carboxyl groups or mixtures of such groups in combination with 95 to 5 percent by weight of a nonionic or an anionic surfactant or emulsifying agent.
For example, 70 to 75 percent by weight vinyl addition polymer emulsifier and 25 to 30 percent of nonionic and/or anionic surfactant are known to provide satisfactory emulsions in accordance with the present disclosure. Particular examples of each of these types of emulsifiers are given later in the specification.
~hen an effective amount of such combinations of emulsifying agents are combined with the organopoly-siloxane resins in the presence of water, a water-based silicone resin emulsion can be provided through the utilization of well known emulsification techniques such as colloid milling. The amount of water present is not critical and will ordinarily depend upon the application to which the emulsion will be put. The amount of water is merely dependent upon a desire to provide a preselected silicone resins solidscontent by weight in the resulting emulsion. As stated, although the amount of water is not critical there will ordinarily be approximately 50 to 300 parts by weight of this water per lO0 parts of the organopolysiloxane resin.
The process of the present invention provides the above described water based silicone resin emulsion compositions by combining the specified constituent ingredients and then applying well known emulsification techniques.

~2~27() DESCRIPTION OF THE INVENTIO
Sili.cone resins which may be used in the compositions of the present invention may be prepared by a number of well known processes such as, for example, by hydrolyzing an organohalosilane blend wherein the eomposition of the resin can be varied by ehanging the proportions of the eonstituent organohalosilanes to be hydrolyzed. An exernplary resin might start with a blend of about 60 mole percent methyltrichlorosilane, about 35 mole percent of phenyltriehlorosilane and about 5 mole percent of dimethyldichlorosilane in the presence of water, aeetone and a water-immiscible organic solvent. In general, this hydrolysis medium could contain from about 1.7 parts to lO parts of water, 0.2 to 5 parts of acetone and 0.3 to 5 parts of said water-immiscible organic solvent per part by weight of the silane blend.
The organo groups in the organohalosilanes to be hydrolyzed are broadly selected from monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals, preferably not exceeding ten carbon atoms. Accordingly, the organo groups can be selected from alkyl groups of 1 to 10 carbon atoms such as methyl, ethyl, propyl, and alkenyl, substituent groups of 2 to 10 carbon atoms such as vinyl, alkyl, mono-nuelear aromatic radicals such as a phenyl, methylphenyl and so forth;
fluorinated alkyl radicals and more specifically fluorinated alkyl radieals of 1 to lO earbon atoms such as trifluoropropyl. Most preferably, the organo groups in the above organohalosilanes are selected from methyl, ethyl, phenyl, vinyl and trifluoropropyl.
The various components of the hydrolysis mixture can be added concomitantly or separately in any desired order. Generally, the organo-halosilanes are added to the mixture of water, acetone and organie solvent.
Preferably, when this method is used a proportion of Erorn 2 to 6 parts of water, about 0.3 to 2 parts of aeetone, and about 0.6 to about 2 parts of organie solvent, per part of the total weight of organohalosilane blend, is employed. It is preferred that the organohalosilanes are added to the hydrolysis medium, rather than vice versa, as this limits the concentration of hydroehloric acid which is formed during the hydrolysis reaction. A
strong hydrochloric acid solution is undesirable in this example as the hydroehloric acid causes acid polymerization of the acetone forming poly-merization products whieh add undesirable eolor to the produet and have a deleterious effect on the physical properties of the product.

`` 12~6270 A preferred method to prepare organopoly-siloxane resins which may he used in this invention is the dual feed process. The dual feed process comprises feeding the ~lend of organohalosilanes and from a~out 0.9 to 5 parts, preferably 0.9 to 1.2 parts of acetone from separate containers and through separate conduits, then premixing them immediately prior to hydrolysis. It is necessary to limit the contact time if small amounts of water are present in the acetoneor in the atmosphere in contact with the organohalosilanes, as the water present causes hydrolysis of the organohalosilanes generating acid which causes the acetone to polymerize. The initial hydrolysis medium prior to the introduction of the silane blend-acetone mixture contains from about 0 to 4.1 parts of acetone and preferably from 0.9 to 1.2 parts of acetone. The amount of water and organic solvent can be as set forth hereinabove, with preferably from about 3 to 3.5 parts of water and 2Q G.9 to 1.2 parts of organic solvent per part of the total weight of the blend of organohalosilanes.
The temperature of the hydrolysis mixture can be con-trolled by the rate of addition of the reagents, or by external heat or by cooling if desired.
During hydrolysis, a temperature of between about 20C
to about 40C is preferred. After the addition of all the reagents is completed, the mixture is generally agitated for an additional period of time such as 15 to 30 minutes or more to allow for complete hydrolysis of the organohalosilanes. The mixture is then allowed to settle and the acid aqueous ~bottom) layer is drawn off from the organic layer. Depending upon individual desires, the organic layer can then he stripped of solvent to a solids concentration of up to laO%. The organic solvent may ~e stripped under reduced pressure or atmospheric pressure. At this point, the resin may be ~2~70 p ,9"
bodied, i.e.,-build u~ ~ molecular weight, under total refl~lx, by condensing and cross-linking silanol units, with the aid of, for example, a catalyst such as iron octoate or Celite ~ iatomaceous earth~ or mixtures thereof, to a desired viscosity, preferably 5-12 cps.
at 25C at 20% by weight resins solids. Moreover, resin impurities may be removed by filtration, using for example, filtering aids such as Celite 5~5 (Diatomaceous earth, sold by Johns Manville), Fuller's earth (calcium montmorillonitel, and mixtures of the same, or simply ~y centrifugation. The resulting silanol-containing organopolysiloxane resin has an organo radical to silicon ratio of about 1.05 to 1.
Included among the water-immiscible organic solvents used in the above-described process for providing silicone resins are, for example, hydrocarbons such as benzene, toluene, xylene and the like; esters such as butyl acetate, ethyl acetate, ethers such as diethylether and the like. Toluene is most preferred because it is a good solvent and has a low boiling point. In general, however, any water-immiscible organic solvent, which is inert to the hydrolysis reactants during hydrolysis and in which the hydrolyzate is soluble to provide for its separation from the aqueous layer, may be used.
Of course, through the process provided by the present invention it is now possible to disperse these heretofore water-immiscible resins in aqueous media.
One of the classes of emulsifying agents required for the water-based silicone resin emulsions of the present invention are vinyl addition polymer products, e.g., polyvinyl alcohol and/or carboxyvinyl polymers. Such products are available, e.g., from Monsanto Plastics and Resins Co., St. Louis, Missouri, U.S.A., trademark GELYATOL and from B.F. Goodrich 1~6270 Chemical Co., Cleveland, Ohio, U.S.A., under its trademark CARBOPOL , respectively. Polyvinyl alcohol is an item of commerce. It is made by hy-rolyzing, with acid or base, a polyvinyl ester, usually the acetate.
The degree of hydrolysis depends on the conditions.
"Completely hydrolyzed" polyvinyl alcohol usually contains approximately 5% residual pendent acetate groups. For the presentinvention, the extent of residual pendent acetate groups can vary rather widely, e.g., from about 5 to about 80%, but preferably from about 5 to about 60%, meaning that the pendent hydroxyl content will vary from about 20 to about 95% and preferably from about 40 to about 95%. The carboxy-substituted vinyl addition polymers are likewise items of commerce. Such polymers are typically white powders, having a slight acetic acid odor, and when dispersed in water become viscous when neutralized, e.g., with sodium hydroxide, or the other bases mentioned balow. Suitable for purposes of this invention are three materials, CARBOPOL M 934, 940 and 941. When neutralized and made up in 0.2% solutions, these vary in viscosity by virtue of differences in molecular weight. The 934 generally falling in the range of

2,050-5,450 Cp; 940 in the range of 15,000-35,000 Cp;
and 941 in the range of 1,950-7,000 Cp in Brookfield test apparatus run at 20 rpm and 25C by well known procedures. A material of the type known as CARBOPOL
941 seems to be especially suitable for purposes of the invention. Acidity is neutralized by reaction with a base, e.g., an alkali metal or alkaline earth metal hydroxide, carbonate, bicarbonate or a primary, secondary or tertiary amine or ammonia, etc., before use.
The other class of required emulsifying agents which are used in combination with the above-described polymerized vinyl products are the anionic emulsifiers such as sodium lauryl sulfate, sodium linear alkyl benzene sulfonate, triethanol amine linear alkyl benzene sulfonate, sodium alpha olefin sulfonate, ammonium alkyl phenol ethoxylate sulfate, ammonium lauryl ether sulfate, ammonium alkyl ether sulfate, dialkyl ester of sodium sulfosuccinic acid, sodium c~ erJe i c~mcne sulfonate, ammonium xylene sulfonate, and ammonium oleate, morpholinium stearate, dimethyl-ammonium linoleate, and the like.
Illustrative nonionic emulsifiers are well known, and include alkylphenoxypoly CethYlene oxyethanol), trimethylnonylpolyethylene glycol ether, and, in general, any of the n-alkyl monoethers which have been A commercially available for a num~beg5~f~ars -- se~
e.g., the above mentioned U.5. ~,05~ 3~.
The water-based silicone resin emulsions of the present invention can be made by any of several methods. Ordinarily the order of addition of ingredients is not critical. O~e suitable method calls for the dispersîon of the vinyl addition polymer agent 2a in water with agitation and heat until the solids - are dissolved. The water phase of the emulsion products can also be added in two, three or more parts, as desired. Ordinarily, from 0.5 to 10 parts by weight vinyl addition polymer and 0.1 to 50 parts by weight nonionic and/or anionic emulsifier per 100 parts by weight silicone resin solids will be effective for emulsifying such resins in an aqueous system.
Those skilled in the art will be able to vary the proportion of the constituent ingredient in order to 3a provide desirable resin emulsion formulations.
Additionally, optional ingredients such as formalin can be used to these emulsions depending upon a given desired end use without seriously detracting from the properties of the water-based emulsion. ~n example o~ a typical silicone resin ~hich can be used in the emulsions and processes of the present invention is SR-141 w~ich is available from the General Electric 12~270 Company.
The composition to be emulsified will then be blended until uniform whereupon emuls~fication can ~e induced by colloid milling of the composition or by homogenization or blending of the composition.
A colloid mill found useful for producing laboratory quantities of these water-based rein emulsions is Manton-Gaulin Colloid Mill, Model 2A.
Such a mill has a 40 mil gap which i5 adjustable from 1 to 40 mils and can be operated at atmospheric pressure or under a feed pressure of 5 to 40 psig N2.
1~ f course, it is contemplated that those skilled in the art wîll be able to scale up ~ process of the present invention in order to produce commercial quantities of these water-based silicone emulsions.
The viscosity of any resulting emulsion can be controlled ~y varying the amount of water included in the blend. This can best be accomplished by first forming a premix comprised of the vinyl addition polymer and silicone resins along with parts of the water.
This premix can be emulsified by combining it with the nonionic and/or the anionic emulsifier and the remaining water. The accompanying examples demonstrate that the water may also be added in three increments.
The organopolysiloxane resins which are utilized in the following examples are comprised primarily of trifunctional units of the formulae CFI3SiO1 5 (T units) and (C6H51 siol 5 (T' units),; and di-functional units of the formulae (CH3~2SiO (,D units), and (C6H5)2SiO (D' unitsl.
3a In the description of each resin, the term silane (,P.B.W.) refers to parts by weight of the requisite organohalosilane precursor of the resin's functional units. Approximate weight percent silane and mole percent silane values are given for the 35 convenience of those skilled in the art. The weight percent siloxane value is indicative of the approximate number of each type of siloxane units present in an average resin molecule. The R to Si Ratio is an expression used by those skilled in the art to ind~cate the approximate relative number of organo radicals associated ~ith each silicon atom and is a useful measure of the degree of tri- and di-functionality in such silicone resins.
SILICONE RESIN --P.B.W. WT. ~ MOL % WT. %
10 UNITS SILANE SIL~NE SIL~NE SILOXANE
T 149.5 24.2 30 17.7 D 129 14.0 20 13.1 T' 211.5 37.4 30 34.23 D' 253 27.4 20 34.97 R to Si ~atio: 1.40 to 1.

SILICONE RESIN - B
~ , . .

P.B.W. WT. % MOL % WT. %
UNITS SILANE SILANE SILANE SILOXANE
T 149.5 8.1 10 5.51 D 129 27.9 40 24.36 T' 211.5 22.9 20 21.24 D' 253 41.1 30 48.89 R. i~ Si Ratio: 1.7 to 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In order to more fully and clearly describe the present invention, it is intended that the following examples be considered as illustrative rather than limiting the invention disclosed and clai~ed herein.
All parts are by weight.

124~6~70 Example 1 The silicone resin to be emulsified was a solid, bodied resin hydrolysis product comprised, of approximately, 35.1% methyl-trichlorosilane, 15.2% dimethyldichlorosilane, and 49.7% phenyltrichlorosilane, by weight.
To a 2-liter stainless steel beaker equipped with an air stirrer there was added 150 g. of the solid silicone resin, 50 g. of an 85%
aqueous nonionic surfactant [50:50 alkylphenoxypoly-(ethyleneoxyethanoltrimethylnonyl polyethylene glycol ether], 300 g. of water, 100 g. of mineral spirits, 100 g. of xylene and 100 g. of 10% polyvinyl alcohol aqueous solution (Gelvatol 20/90). The premix was blended until uniform, then colloid milled (4 mil gap at atmoc-pheric pressure). The resultant emulsion had a viscosity of 1420 cps., solids content of 24.7% and was uniformly milky white in appearance. When centrifuged for 30 minutes at 3000 RPM, a 40 cc.
sample was found to have no visible separation --top or bottom. Coating the composition on an aluminum panel produced a uniform coating free of the creep noticed when the resin was emulsified with only the nonionic component in the blend of the Example.
Example 2 A blend of 187 g. of dry powdered silicone resin powder as described in Example 1, 60 g. of titanium dioxide, 19 g.

of nonionic emulsifier (Example 1), 85 g. of 10%
polyvinyl alcohol solution, 282 g. of water, 37 g. of perchloroethylene solvent, and 94 g. of N-propoxy-propanol was uniformly mixed. Thus the resin water base premix was changed to 100 g. of 10% polyvinyl alcohol solution and 100 g. of odorless mineral spirits.
Next was added 10 g. of methylphenylsilicone oil and 1/2 g. of iron octoate catalyst.
The premix was blended in a stainless steel beaker with an air-drive stirrer until uniform.
Then it was colloid milled through a mill set at 4 mil gap. The resulting paint containing emulsified silicone resin was found to contain 28.6% solids and have a viscosity of 1034 cps.
When a 40 ml. sample was centrifuged for 30 minutes at 3000 rpm, there was no visible separation, to or bottom. When an aluminum panel was coated with the paint and cured for 1 hour at 105C., a uniform coating, free from voids, was obtained.
Example 3 A carboxylated high molecular weight vinyl addition polymer (B.F. Goodrich Company, Carbopol 941~, 2 g., was dispersed with rapid agitation in 940 g. of deionized water at 50C.
There was then added 2.8 g. of 6-acetoxy-2,4-dimethyl-m-dioxane presservative (Givandan Corp., Clifton, New Jersey, U.S.~., Giv. Gard DXN~
and 8.3 g. of 10~ aqueous sodium hydroxide solution.
Next was added 81 g. of 10% a~ueous sodium hydroxide solution. Next was added 81 g. of the 85%
active nonionic emulsifier blend and 1757 g.
of a solution of silicone resin.

i2'~Ç;270 The silicone resin was an 80% silicone resin solids compositions, VM & P naptha solvent, and was primarily comprised of the hydrolysis products of 8.1%
methyltrichlorosilane; 27.9% dimethyldichlorosilane;
22.~% phenyltrichlorosilane; and 41.4% diphenyldichloro-silane C5ilicone Resin - B, above~.
The mixture was dispersed with highagitation.
Then 80 ~. more of nonionic emulsifier blend (Example 12 and lOQ g. of water wa.s added. The premix lQ wa5 blended and colloid milled through a 5 mil gap at atmospheric pressure. The resulting milky white emulsion had a viscosity of 1573 cps., a soiids content of 51.6% and a pH of 5.8. When a 40 ml.
portion was centrifuged for 3Q min. ~t 3000 rpm, less than 1 ml. of separation was noticed on either top or bottom.
EXAMPLE ~
There were ~lended 0.5 g. of preservative (Giyandan Corp., Giv Gard DXN~, 0.7 g. of car~oxylated 2Q high molecular weight vinyl addition polymer ~Car~opol 941L, 3 g. of 10% aqueous sodium hydroxide solution, and 366.8 g. of water at 60C. for 1 hour, to disperse and neutralize the carhoxy vinyl polymer.
Six hundred grams of silicone resin solution were ~lended with 30 g. of an 85% active nonionic emulsifier solution ~Example 1~.
S;/ ,'co r)e, The -s-i-~it~ resin solution was a 50% resin solids solution in toluene and was primarily comprised of the hydrolysis products of 4a mole ~ of methyltri-3Q chlorosilane, 30 mole percent of phenyltrichlorosilane,2Q mole % of diphenyldichlorosilane (~Silicone Resin - A, aE: oYel -Once the resin solution and the emulsifier were uniformly blended, the neutralized carboxy Yinyl polymer solution was added. The premix was blended and then passed through a colloid mill set at a 5 mil gap 6osI-4Q9 and under atmospheric pressure. The resulting emulsion of silicone resin had a solids content of 33.1%, a pH of 6.0 and a viscosity of 30QQ cps. When a 40 ml. sample was centrifuged for 30 min. at 3000 rpm, no visible separation was noted. The emulsion was aged one month at 50C in an air circulating oven and the shelf stability was found to be excellent.
EXAMPLE ~
~ To 600 g. of the silicone resin solution of Example ~was added lOa g. of polyvinyl alcohol solution (Example l). The premix was blended and a solution containing 5 g. of sodium lauryl sulfate ~anionic surfactant~ in 295 g. of water was charged.
The premix was blended for one hour and then colloid milled at a 6 mil gap, atmospheric pressure. The emulsion was found to have a viscosity of lO00 cps, pH of 7.0, and solids content of 31.8%. When a 40 ml. sample was centrifuged at 3000 rpm for 30 minutes, 2a there was not visihle separation, top or bottom. When a sample of the polyvinyl alcohol-containing emulsified silicone resin was aged in a 50C oven for one month, shelf stability was found to be excellent.
EXAMPLE
To 600 g. of the silicone resin of Example~
was added lO0 g. of the polyvinyl alcohol solution of Example l and the mixture was blended. Then was added a solution of 2 g. of the potassium salt of dodecylbenzene sulfonic acid (anionic) dissolved in 298 g. of water.
The mixture was ~lended for one hour, and the colloid milled at 6 mil gap and atmospheric pressure. The emulsion obtained had a viscosity of 4100 cps, a pH of 6.3 and a solids content of 3.12~. When a 40 ml. sample was centrifuged for 30 min. at 3000 rpm, no visible separation was noted--only surface skinning due to drying.
A sample placed in a 50C. oven for one month, and it aged well.

EXAMPLE-~r To 600 g. of the silicone resin of Example-~was added 14.1 g. of oleic acid and the mixture was well blended. Then a solution was added comprising 0.2 g.
carboxy vinyl polymer (Carbopol 941~, 3 g. of 28~ aqueous ammonium hydroxide and 382.7 g. of water. The premix was stirred for one hour and then colloid milled with a 6 mil gap at atmospheric pressure. The resulting emulsion had a viscosity of 290Q cps, a pH of 8.8 and a solids content of 31.9~. When a 40 ml. sample was centrifuged for 3Q minutes at 30Q0 rpm no visible separation was noticed. A sample was aged at 50~C
for one month and shelf stability was found to be excellent.
Silicone resins of the type used herein are recommended and utilized in the preparation of various paints and coatings. Environmental restrictions are foxcing industry to install either costly solvent recovery systems or switch to less environmentally-sensitïYe solvent systems. Incorporation of resin solut~ons into water based systems are effective solutions to governmental requirements for less pollution. Emulsification of existing silicone resin compositions into water based systems has not been too easily achieved heretofore, but is readily accomplished according to the present invention. The vinyl addition polymers used herein permit formulated emulsions to dry without the formation of "fish eyes" and creeping associated with the use of ætrictly nonionic suxEace actiYe agent systems.
Many variations will suggest themselves to those skilled in the art in light of the ahoye-detailed descxiption. All such o~yious variations are within the full intended scope of the appended claims~

Claims (24)

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

1. A uniformly coatable water-based silicone resin emulsion substantially free of mica and talc comprising:
(a) 100 parts by weight of at least one organopolysiloxane resin composition consisting essentially of up to 50 percent by weight monofunctional units of the formula R3SiO0.5, up to 60 percent by weight difunctional units of the formula R2SiO, up to 100 percent by weight trifunctional units of the formula R SiO1.5, and up to 60 percent by weight tetrafunctional units of the formula SiO2, wherein R is a substituted or unsubstituted monovalent hydrocarbon radical selected from the group consisting of methyl and phenyl radicals and said organopolysiloxane resin has an R to Si ratio of, approximately, 1.0 to 1.99 R groups for each silicon atom, said organopolysiloxane resin being dispersed in up to 500 parts by weight of an organic solvent, per 100 parts by weight of the organo-polysiloxane resin;
(b) 0.25 to 50.0 parts by weight of a combination of emulsifying agents per 100 parts of said organopolysiloxane resin wherein said emulsifying agent combination consists essentially of 5 to 95 percent by weight of an emulsification agent comprising a vinyl addition polymer having pendant hydroxyl groups or pendant neutralized carboxyl groups and 5 to 95 percent by weight of a nonionic or an anionic surfactant, and wherein said combination of emulsifying agents is effective for dispersing said organopolysiloxane resin in a water-based emulsion;
and (c) sufficient water to produce a stable aqueous emulsion.

2. A water-based silicone resin emulsion as in claim 1 wherein said water is present in an amount effective for providing an emulsion having a preselected silicone resin solids content by weight.

3. An emulsion as in claim 2 wherein said water is present in an amount of, approximately, 50 to 300 parts by weight per 100 parts of said organopoly-siloxane resin.

4. An emulsion as in claim 1 wherein said organic solvent is selected from toluene and xylene.

5. An emulsion as in claim 1 wherein said monovalent hydrocarbon radicals are selected from, independently, the group consisting of methyl and phenyl radicals.

6. An emulsion as in claim 1 wherein said organopolysiloxane resin is comprised of, approximately, 5 to 40 percent by weight CH3SiO1.5 units, zero to 35 percent (CH3)2SiO units, 15 to 65 percent (C6H5)2SiO1.5 units, and zero to 50 percent (C6H5)2SiO units, wherein there is present, approximately, 1.0 to 1.8 organic radicals for each silicon atom.

7. An emulsion as in claim 1 wherein said vinyl addition polymer emulsification agent is selected from polyvinyl alcohol and a neutralized carboxyvinyl polymer of high molecular weight and combinations thereof.

8. An emulsion as in claim 1 wherein said anionic surfactant is selected from the group consisting of sodium linear alkyl benzene sulfonate and ammonium oleate.
9. A process for providing a uniformly coatable water-based silicone resin emulsion

Claim 9 continued:
substantially free of mica and talc comprising the steps of:
(I) combining (a) 100 part by weight of at least one organopolysiloxane resin composition consisting essentially of up to 50 percent by weight monofunctional units of the formula R3SiO0.5, up to 60 percent by weight difunctional units of the formula R2SiO, up to 100 percent by weight trifunctional units of the formula R SiO1.5, and up to 60 percent by weight tetrafunctional units of the formula SiO2, wherein R is a substituted or unsubstituted monovalent hydrocarbon radical selected from the group consisting of methyl and phenyl radicals and said organopolysiloxane resin has an R to Si ratio of, approximately, 1.0 to 1.99 R groups for each silicon atom;
(b) an amount up to 500 parts by weight, per 100 parts by weight of said organopolysiloxane resin, of an organic solvent sufficient to disperse the organopolysiloxane resin;
(c) 0.25 to 50.0 parts by weight of a combination of emulsifying agents per 100 parts of said organopolysiloxane resin wherein said emulsifying agent combination consists essentially of 5 to 95 percent by weight of an emulsification agent comprising a vinyl addition polymer having pendant hydroxyl groups or pendant neutralized carboxyl groups, and 95 to 5 percent by weight of a nonionic or an anionic surfactant, and wherein said combination of emulsifying agents is effective for dispersing said organopolysiloxane resin in a water-based emulsion; and (d) sufficient water to provide a stable aqueous emulsion and (II) emulsifying said combination if (a), (b), (c) and (d).

10. A process as in claim 9 wherein said emulsifying step is accomplished by colloid milling.

11. A process as in claim 9 further comprising the step of preblending said combination of emulsifying agents or a portion thereof with a portion of said water prior to combining said emulsifying agents with said organopolysiloxane resin and a remaining portion of water.

12. A process as in claim 9 wherein said water is present in an amount effective for providing an emulsion having a preselected silicone resin solids content by weight.

13. A process as in claim 12 wherein said water is present in an amount of, approximately, 50 to 300 parts by weight per 100 parts of said organopoly-siloxane resin.

14. A process as in claim 9 wherein said organic solvent is selected from toluene and xylene.

15. A process as in claim 9 wherein said monovalent hydrocarbon radicals are selected from, independently, the group consisting of methyl and phenyl radicals.

16. A process as in claim 9 wherein said organopolysiloxane resin is comprised of, approximately, 5 to 40 percent by weight CH3SiO1.5 units, zero to 35 percent (CH3)2SiO units, 15 to 65 percent (C6H5)SiO1.5 units, and zero to 50 percent (C6H5)2SiO units, wherein there is present, approximately, 1.0 to 1.8 organic radicals for each silicon atom.

17. A process as in claim 9 wherein said vinyl addition polymer emulsification agent is selected from polyvinyl alcohol and a neutralized carboxyvinyl polymer of high molecular weight and combinations thereof.

18. A process as in claim 9 wherein said anionic surfactant is selected from the group consisting of sodium linear alkyl benzene sulfonate and ammonium oleate.
19. A storage stable, uniformly coatable silicone resin emulsion substantially free of mica and talc coating composition comprising an aqueous emulsion of (a) 100 parts by weight of at least one organopolysiloxane resin composition consisting essentially of up to 50 percent by weight monofunctional units of the formula R3SiO0.5, up to 60 percent by weight difunctional units of the formula R2SiO, up to 100 percent by weight trifunctional units of the formula R SiO1.5, and up to 60 percent by weight tetrafunctional units of the formula SiO2, wherein R is a substituted or unsubstituted monovalent hydrocarbon radical selected from the group consisting of methyl and phenyl radicals and said organopolysiloxane resin has an R to Si ratio of, approximately, 1.0 to 1.99 R groups for each silicon atom, said organopolysiloxane resin being dispersed in up to 500 parts by weight of an organic solvent, per 100 parts by weight of the organopolysiloxane resin; and (b) 0.25 to 50.0 parts by weight, per 100 parts by weight of said organopolysiloxane resin, of

Claim 19 continued:
an emulsifying agent consisting essentially of (i) 5 to 95 percent by weight of an emulsification agent comprising a vinyl addition polymer having pendent hydroxyl groups or pendent neutralized carboxyl groups, and (ii) 95 to 5 percent by weight of a surfactant or combination of surfactants selected from the group consisting of sodium lauryl sulfate, sodium linear alkyl benzene sulfonates, triethanol amine linear alkyl benzene sulfonates, sodium alpha-olefin sulfonates, ammonium alkyl phenol ethoxylate sulfates, ammonium lauryl ether sulfate, ammonium alkyl ether sulfates, dialkyl ester of sodium sulfosuccinic acid, sodium cumene sulfonate, ammonium xylene sulfonate, ammonium oleate, morpholinium stearate, dimethylammonium linoleate, alkylphenoxy-poly(ethylene oxyethanol), trimethylnonyl-polyethylene glycol ether, and n-alkyl monoethers.

20. The coating composition of claim 19, wherein said emulsification agent (b)(i) is selected from the group consisting of polyvinyl alcohol having from about 20 to about 95 percent pendent hydroxyl groups, and carboxy-substituted vinyl addition polymers wherein the carboxy functionality is neutralized by reaction with a base.

21. A coating composition as defined in claim 20, wherein said emulsifying agent (b) consists of about 70 to 75 percent by weight of an emulsification agent (b)(i) and about 25 to 30 percent by weight of a surfactant (b)(ii).

22. A coating composition as defined in claim 19, wherein said aqueous emulsion is prepared using approximately 50 to 300 parts by weight of water, per 100 parts of the organopolysiloxane resin (a).

23. A coating composition as defined in claim 19, wherein said aqueous emulsion further contains (c) up to 500 parts by weight, per 100 parts by weight or organopolysiloxane resin (a), of an organic solvent selected from toluene and xylene.

24. A coating composition as defined in claim 19, wherein said organopolysiloxane resin is comprised of, approximately, 5 to 40 percent by weight CH3SiO1.5 units, and up to 50 percent (C6H5)2SiO units, wherein there are present, approximately, 1.0 to 1.8 organic radicals for each silicon atom.