CQftTIISJGS CN SuBSTRA-CES

The present invention concerns the field of surface coatings, naπely varnishes, lacquers, enamels and paints based on organic po- lymers and resins. It rrore especially concerns the cαη?ositions for coating Substrates, the prcduction of polymer mater als eπployable 5 for coating or as binders in coating coirpositions and the applica- tion of coatings cn Substrates.

It is nown that the fundamental ingredients of ccπpositicns for applying σn Substrates non-transparent coatings in the fluid Sta¬ te (uncured) and curing after application include a binder (one or I_Q more copolymerizable cnαraers and/or prepolymers) and a load or Char¬ ge of dispersed solid particles (organic or mineral pigments. dilu- ting fillers or extenders, or others) . The object of these particles is mainly to iiηpart to the coating film suitable σpacity, σolor and certain physicc-chemical properties (for instance, resistance to 5 abrasion) . The object of the binder is to adhere the coating to the Substrate, to eπfced and to bind together the solid particles and al¬ so to provide certain properties to the coating, e.g. flexibility, hαncgeneity, good surface appearance and proper resistance to age- ing. 0 ^Ifc is generally advantageous in the coating cαrpositions to incorporate to the binders rather large guantities of particulate charges (to provide more vivid σolors, better ccvering capacity, more econcmical prcduct, etc.) . Bowever, the aπount of particulate Charge to be incorporated into binders is limitsd by the degree of 5 cαipatibility (wettability) of the particles of the Charge with the organic binder. In many cases, the solid particles are organσphobic (e.g. Si0 ₂ , AI2O3, i0 ₂ ) and do not well disperse into the organic materials ( onesners, prepolymers, etc.) which are constituents or precursors of the binders. Consequently, one has scught to a e these 0 particles organophilic by grafting cn the surface thereof radicals or organic chains cαrpatible with the binders mplσyed and allcwi g said particles to beσαme "intimate" with said binders.

Thus the present inventors have recently disclosed a cσmposi-

tion for making photccurable coatings (see International Patent Ap¬ plication _o. PCT EP8200004) coπprising, as binder phase, photopo- lymerizahle -ncnαners and, as Charge, SiO- or AI-O3 particles bear- ing, grafted thereon, hydrocarbon chains. Hie presence of such chains allows very large ratios of mineral charges to be incorporated irt- to the binder without iπpairing the essential properties of the coat¬ ings frαn said cαrpositions (transparency, flexibility) . Moreover, the presence of high levels of mineral charges in the coatings subs- tantially irrproves certain properties such as, for instance, the re- sistance against abrasion.

One has nσw further discσvered that he ay still iπprove the intrinsic properties of coatings ccntaxning charges of dispersed par¬ ticles when the latter are chemically linked to the resins of the binders. Ηius, it has been noted that if sαπe copolymerizable func- ticns grafted to the solid particles of the Charge are made to par- ticipate to the polymerization reactions leading to the noππal for- maticn of the binder of the coating cαrposition, said partides are incorporated to said binder in the form of a quasi-hcmcgeneous pha¬ se which provides particularly favorable ρhysic_κ_-che_nical properties to said coating. Mareover, one has noted that the particles of a graft¬ ed Charge, even the smaliest ones, ought to σarry each a number of copolymerizable functions generaliy exceeding 2 and the use of such grafted particles as co- αiαners does lead to a significant degree of cross-linking in the organic poly er, such σross-linking being intended to ccntribute to the odification and enhancεment of the properties of the coating. Ulis cross-linking cccurs because the copo¬ lymerizable graft functions are indeed chemically cσnnectεd together through the bcdy of the particle.

Hence, in the fi st place the invention concerns a methcd for the prcduction of coatings of cross-linked polymerized resins con- taining a Charge and the deposition thereof on Substrates. Accord- ing to this method, one provides for the inti ate diqoersicn of par¬ ticles of at least one kind ^* of mineral or organic Charge into an or¬ ganic phase ccntaining one or more copolymerizable mcncmers and, op- tionally, other additives such as solvents, stabilizers, polymeri¬ zation catalysts, antioxidants, fungicides, etc., such particles bear- ing, grafted cn the surface thereof, organic chain-like substituents

O PI

- Z -

carrying organic functions capable or σopolymerizing with said mo- nαmers; then one applies a layer of the resulting dispersion on a Substrate and one σauses the hardening of this layer by regul r cur¬ ing and polymerization. 5 By analogy, one can apply this methcd to the prcduction of ho- ogeneous binder-σharge phases eπjploya le in coating co positions. In this case, one also disperses a Charge of particles having graft¬ ed thereon copolymerizable functions in an organic rrcnαneric and/or prepolymeric binder phase and one causes hardening or prehardening

10 (preliminary curing) of the dispersion: then the latter is thereafter incorporated as the base ingredient into a coating cαrposition accord- ing to usual techniques, i.e. with addition of the ingredients nor- ally added to paints and varnishes such as solvents, curing agents, corrosion inhibitors, antioxidants, detergents, fungicides, etc. ,

15 and the resulting cαrcosition is eπployed for making coatings under usual practice.

Preferably, the grafted organic groups or chains discussed here have the foππula:

wherein the curved line sche atically represents a portion of the 25 surface of a particle, R is a linking bifunctional aliphatic or cy- σlcaliphatic radical and A represents the said copolymerizable func- tion to be defined ater. The valencies represented free cn the oxy- gen atαπs can be connected to hydrogen atαms, or to Si ato s of neigh- boring grafted chains, or to atoms of the particle near the surfa- 30 σe thereof, provided that such atoms are bindable, as shown in the foππula, to said chain substituent. For illustration purpose, if the particle is made of silica, the free hydroxy groups of the Silicon atαra of the chain represented in formula I can condense by dehydra- tion with the nearby hydroxylated Si atαrs on the particle to give

-._• ' '

35 a tridimensional network (-Si-O-Si-) . Ulis type of reacticn has been

/ ι detailed in the aforementiσned applicaticn PCT E_P82/00004.

The nature of the linking group R is rather unrestricted, the

OMPI

latter coπprising frora 1 to about 20 carbon atαns (this upper rän¬ ge not being limitative) . R can be straight chained, branched or cy- σlic and it can carry other functions that should not be reactive under conditions when A copolymerizes with copolymerizable mcnomers and/or prepolymers. For instance, amcng others, R can carry inter- mediate functions such as -CC-, -O-, -NR ¹ -, -S-, etc., R' being any hydrocarbon radical.

The function A is a reactive function for participating to the general polymerizaticn reaction scheue leading to the build-up of the coating or of the binder in the coating and its nature is thus related directly to the polymerizable System involved.

For instance, in the case of polyurethane or polyurea resins (ofatained frcm diisccyanates and diols or diamines) , A can be a func¬ tion such as -NCO, -CH, -NH- or -NRH. In the case of polyolefins polymerized thermally or σatalyti- cally, A can be a fuπcticn with unsaturated carbons such as the fol- lcwing functicans: vinyl, allyl, acrylic, butadienyl, etc.

In the case of epoxy-resins, A can be the functions oxirane, -NH^ -NR'H, -CH, -SH. with polyesters or alkyd resins, A can be -CH, -CCH, -CCC1. The species for A is therefor selected as a function of the needs, i.e. depending on the sort of resins and particles used, de- pending cn the rcutes of synthesis for the σoitcounds used for graft¬ ing and depending on the σαππercial availability of the starting matε- rials and end prcducts.

Under usual practice, it is advantageous to carry out the graft¬ ing reaction by means of ccjirpcunds of foππula

(HO) ₂ Si- rA (II)

wherein the Symbols are the saue as in foπmla I, the linkage by graft¬ ing being effected. by the dehydration of one or more of the nearby GH functicns belonging to the particle with corresponding functions of cccπpouiTd II. The preferred oute to prccure coπcound II is meit- tiαneά hereinafter.

The kinds of charges of solid dispersible particles to be used within the scope of this inventiαn are maπy and include most solid

MH

- 3 -

materials known in the fieJLd of paints, varnishes, lacquers, inks, enamels and similar products, provided they carry functions with la¬ bile hydrogen atoms suitable for being grafted; a preferred exaπple of such functions is the -OH group included in mineral bases, alσo- hols, phenols or molecules of water of hydration.

As ncn-limitative exairples of fillers, pig ents and other par¬ ticulate mineral charges, the following can be recited: alumina hy- drate, antimony oxide, a≤bestos, baryu etaborate, basic baryum Sul¬ fate, iron oxide, blanc fixe, cadmium sulfide and other cadmium pig- ments, CaCC , calciu silicate, calcium pluπfaate, calcium olybdate, σhromium yellow, chromium green, C∑ ₂ 0 ₃ , cobalt blue, copper chrαni- te, cuprcus oxide, 3BaS0 ₄ .Al(OH) ₃ ; kaolin, clay, basic lead σarbo- nate, dibasic lead phosphite (2PbOR-HEO ₃ .0,5H ₂ O) , basic lead Sulfa¬ te, lithopone, manganese violet (H ₄ NMn ₂ 0w) , red and yellow ercu- ryσxide, mica, molybdate orange (25P-_C-Ω..4PbMo0 ₄ .PbS0 ₄ ) , nickel anti- cnititanate (NiO.Sb ₂ θ3.2OTi0 ₂ ) Si0 ₂ (novaculite, pumice, silica, aerogel, amorphous silica, etc.), scdio-aluminosilicate, talc, Ti0 ₂ , ultra-marine ^' blue, zinc basic chrαnate, zinc ferrite, ZnO, zinc basic molybdate, zinc phosphate, zinc yellow (4ZnO.K ₂ o.4Cr0 ₃ .3H ₂ 0) , Sn0 ₂ most metals in finely divided form.

As organic pigments, the following non-limitative exanples can be recited: nickel yellcw azo, rouge para, red pigment 6, lithol red, manganese red BON, alizarines, orange 2, azobordeaux.

In addition to the above particulate charges, the invention al- so applies to fibrcus charges such as glass or ceramic fibers. Other examples of charges are found in the following references: "Pigment Handbook", T.C. PAI CN, Wyley-Intersc. Publ. (1973) .

Of course, grafting σannot be dcne directly cn surfaces which are ncn-reactive toward the -Si(0H) ₃ grαup, for instance carbcn black surfaces? in this case, one must first graft hydrophilic chains on the particles of car on black (this technique is disclosed in Patent

Application EP 82 810 295.4) .

To effect grafting leading to particles carrying chain substi¬ tuents like in for ula I, one can advantageously proceed as follcw: cne treats a trialkoxysilane or a trihalogenosilane in aqueous me- diu for hydrolyzing it into a σorresponding trihydrαxysilane. Then one adds the Charge of particles to be grafted to the hydrolysis ms-

OKPI

- β -

dium and one agitates the ixture during a ti e sufficient for bond¬ ing by condensaticn ost of he trihydrσx silane olecules on the sur¬ face of the particles. Then, one separates by usual eans the liquid front the grafted Charge (evaporation of the solvent, filtration, cen- trifugaticn) , and the latter is dried, for instance under vacuum at 50—150°C. Alternatively, Separation and drying can be effected si- ultaneousl , for instance by subjecting the organic or aqueous dis¬ persion of the grafted Charge to spray-drying.

To effect the hydrolysis, one can prcceed, depending on the case, in acidic or alkaline medium. An alkaline raedium is convenient for silanes carrying a -NIL functicn; an acid medium, for instance at pH ccntrolled between 3 and 5, is convenient for other silanes to minimize possible self-condensation into polysi-Lαxanes. When A is an epαxy function, hydrolysis is preferably brought about under neu¬ tral ccnditicns. In case where the cccolymerizable functicn is sen¬ sitive to water (for instance a -NCO group) one can also effect the grafting in anhydrous medium (dioxane, toluene, xylene or EMF) by eπplcying a trialkoxysilane not previously hydrolyzed. After graft¬ ing, the grafted Charge is then di ectly usable for the preparation of the coating cαπpositions as previously stated.

A ong the trialkox silanes which are hydrolyzable into corres- ponding σαmpounds II or which are usable directly as entioned above, one can recite the following ccinpounds: vinyl-triethoxysilane, CE sCHSi(CC^) ₃ ; vinyl-tri ethoxysilane, CH_=CΞSi(CCE,) ₃ ; vinyl-t iφ-πεthαxyethoxy)silane , ₃ ;

2-(trimethoxysily1)e hyl methacrylate,

(C^O)^iC^COCC(CΞ^=CΞ ₂ ;

3-(triethoxysilyl)propyl methacrylate,

(C^O)^iC^CCCCtCH^ -<B_

4-(trichlorosilyl)butyl acrylate; 6-(tricyclohexyloxysilyl)hexyl methacrylate; 11-(trimethσxysilyl)undecyl methacrylate; 18-(triethoxysilyl)cctadecyl acrylate; p-[3-tr__methcκysily--prσpyl]-styrene; glycidoxyprσpyl-trimethoxysilane; trimethoxysilylethyl-3,4-epoxycyclohexane;

N-triethαxysilylprcpyl-αnine; N-tr-__rethoxysilylprσpyl-N(/^aminoethyl)amine; N-tr-lmethoxysilyluiTdecyl-amine; 3-isccyanatopropyl-tri ethcxysilane; -hydroxvethyl-triethoxysilane; Y-mercaptopropyl-trimethcx silane.

A more σo plete list of silane coπpounds usable in the inven- tion is found in ÜSP 4,026,826 cited as a reference. It will be not¬ ed that it has been already disclosed (see ÜSP 3,419,517) that char¬ ges such as Al ₂ 0 ₃ , quartz, silicagel, σarbon black, graphite, metal pcwders, CaCO-, etc. can be treated with silane derivatives such as the aforementicned kinds; then the charges thus treated are incor¬ porated into resins (for instance, polyaraides) as reinforcing agents. When this incorporation is carried out (see col.12 and 13 of the above cited reference) , the reactive groups of the silane cαrpounds are capable of reacting with the foππed polymer chains and providing Che¬ mical bonds therewith. It does not appear to be suggested hcwever in the reference that such reactive groups can copolymerize with the reacting mα ^* _omers as in the present inventicn. Moreover, there are neither suggestions that polymers so reinforced can be used as coat¬ ings on Substrates. On this kind of subject, one can further σite the following references: USP 3,328,339; 3,324,074; 3,328,231, GB 1,110,930; 1,146,085 and NL 69/01148.

Among the resins used generally in the field of industrial coat- ings whose mcnαners and/or prepolymers σonstituants are suitable in the invention, one can recite, as examples, the following products: alkyd resins; mixed phenoplast-alkyd resins; alkyd-chlorinated rub- ber; alkyd-polystyrene; alkyd-diisccyanate; alkyd-.vinyl-epoxy; akyd-amincplast; alkyd-silicone; epoxy-aminσplast resins; vinyl-phe- nolacetal; epcxy-phenoplast; polyesters; polyamides; polyurethanes; polyvinyl acetals; polyester-styrene; epoxy-polyamide; »-iBlaπ-ine-formal- dehyde; phenolformaIdehyde, etc.

The πonαners usable within the scope of the present invention comprise ost of the coπξxxinds which are suitable for the prcduction, by polymerization and ccpolyme izaticn, of resins applicable for coat¬ ing surfaces or as binders in coating coirpositions. Etetailed lists of such mcnαners are availahle fron publications devoted to the field.

e.g. Encyσlcpedia of Polymer Science & Technology. .

For instance, sσne of the most cαiu ily used cnαmers suitable in the field of polyamides, polyesters, polyethers, epoxides, poly- imides, polyurethanes, etc. are listed belcw: Diaeids: σarbon dioxide, oxalic, glutaric, adipic, pi elic, su- beric, azelaic, sebacic, maleic, phthalic, terephthalic, isαphthalic aeids and the like.

Diamines: ethylenediamine, hexamethylenediamine, hydrazine, pipe- razine, and the like. Alcohols and phenols: etfaylene glycol, di- and triethylene-gly- σol, polyalkylene-glycols, polyethylene-glycol, polypropylene-gly- col, neopentyl-^glycol, 1,4-butanediol, cyclchexanedimethanol, bisphe- nol-A, trin-Sthylolpropane and the like.

Diisocyanates: 2,4- and 2,6-toluene-diisccyanate, dipheπylmethar- ne-4,4 ^I -diisccyanate, cyclohexane-diisocyanate, p-phenylenediisceyanate, hexamethylene-diisocyanate, and the like.

Other examples of πcncπiers and prepolymers convenient for the iπventicn are to be feund in the beok: "Encyclopedia of Polymer Science & Technology", WüLEY & SCNS (1972) and also, particularly in regard to olefinic πcnαners and prepolymers, in International Appli¬ cation Sto. PCT/EP82/00004 and in the aforementioned OS Patents listed as references.

Fro the foregoing description, it is seen that the cαrposition of matter usable aecording to the invention mainly consists, in the first place, of one or more polymerizable monomers and/or ccpolymers and in the second place of a Charge of particles bearing, grafted on the surface thereof, organic substituent chains provided with func- tiens that can ccpolymerize with the monαners. In addition, the com- position can coπprise other ingredients ccπirDnly used in coatings, such as polymerization catalysts, adhesion promotors, bacterieides, fungieides, additicnal inert fillers, possible solvents, antioxidants, etc.

In general, the ccrrpositiα is prepared just before use to avoid hardening during storage. This precaution is however not necεssary in the cases where curing is only induced by heat. Hence, depending on the cases and on the kind of polymeric resins used, the manner in which the cαrponents of the ccπposition are used and are present- ϊfRE O PI

ed for sale may be subject to racdifications. For instance, in the case of polyurethane resins, one can cαπmercialiy offer a product σonsisting of, cn one hand, a polyol σαnponent containing a Charge with particles grafted with chain Segments carrying hydrσxy or amine functions and, on the other hand, a polyisocyaπate cαmponent (the possible further additives belonging to one or the other σoπponent) . Both cαηponents are mixed just before use and the resulting ccπpo- sition is used for coating Substrates e.g. bodies of vehicles, cons- tructicn panels, miscellaneous articles and others. Curing of the coating takes place either spcntaneously at ordinary temperature, or it can be accelerated by heat and-moisture. Naturally, it is also possible to offer a similar product using a reversed arrangement, i.e. a polyisocyanate ccπponent containing the Charge particles graft¬ ed with i≤ccyanato-a-Lkyl≤ilanes and a charge-free polyol coπpcnent. Analogcus techniques are suitable in the cases of Systems involving other resins, e.g. alkyd, polyesters, polyamides, epoxy, etc. In the case of polyolefins, polymerizaticn is generally induced by heat or by the effect of catalysts or both. A list of suitable σatalysts is given in <S 1,146,085 page 9. In this case, it is preferrable to first- ly mix the Charge (the particles of which bear, grafted thereon, un- saturated chain segments) with the unsatured monαners of the cαrpo- sition (ingredient a) and to add the σatalyst or curing agent (in- gredient b) just before use. Optional further additives may be in¬ corporated in one or the other of ingredients a and b. With regard to the relative proportions of the ingredients in- σluded in the present coirposition, the following data can be provid¬ ed:

When effecting the grafting Operation on the particles of the Charge with trihydrαxYsilane coπpounds, one can admit grafting levels in the order of 0.1 to 50% by weight, preferably 10 to 40%. It ≤ϊhould be σlear that the high values of this ränge refer to charges with large area per weight (for instance like with pyrcgenic silicas where the specifiσ surface figure is in the order of 30-400 nfi/q) , where- as the lcw values of this ränge refer to low specific surface par- ticles (e.g. Ti0 ₂ with about lOir^/g; blanc fixe with about 4 rr^/g, chrαnium orange about 1 data can be provided: for instance, AERO5IL-2Q0 (a pyrogenic silica)

is in the form of particles of about 10 nm size (surface Λ 3x10-16^2) on each of which one can attach (graft) about 1000 to 2000 siloxane functions (about 300 - 600 x lθlδ substituents/m2; 0.5 - 1 _x Q-5 mole^a ² . Since the specific surface of this silica is 200 mVg, a grafting density corresponding to the high value of the afore ention- ed ränge comes approximately, by weight, to the ränge of 0.1-2 parts of a siloxane (such as tr-hyfrcxya_ιιincpropylsilane or other hydro- xysilanes or corresponding alkoxysilanes) for one part of Charge. It is noted that the degree of ho ogenei y of the binder-charge phase is a function of the grafting level as well as are other properties such as shcck and abrasion resistance, resistance to corrosion, flexi- bility, etc. for a given charge/binder ratio. It is also evident that the technique resulting fron the present invention provides more signi- ficant cαiparative results at high filier levels and with particles with high values of specific surfaces than at low Charge levels. The percent by weight of grafted Charge incorporated into the organic phase of the present conpositions ranges fron about 10 to 52%.

In conclusiαi, the present invention permits, in view of the possibility of increasing the Charge density in the binder of coat- ings and of iπproving the affinity of the charges tcward the orga¬ nic phase, to attain the following objectives: to provide coating ccπpositions with high ratios of mineral charges to organic cαico- nents with still acceptable vi≤cosity; to inprσve the adhesion of coatings on Substrates and their resistance to scratching, σracking and ageing. To iaprove the modulus and flexibility of coatings while decreasing their permeability to moisture and porosity. To iπprove the resistance to wear and tear, to abrasion and to weathering agents. This prσperty is particularly valuable for σoated structures exposed to general out-dcor ccnditicns or to sea-water. The trialkoxysilanes having substituents in the silane chain capable of copoiyme izing with πcnαners for providing binder phases suitable in the present coatings can be obtained by several methcds nown by people skilled in the art and taught in the technical lita- rature. Also, many of the trialkoxysilanes usable in the invention are cαππercially available (e.g. fron the UNION CARBIEE COMPANY) . Other general informaticn on these ccπpounds is found in the publi¬ cation: "Silicone Technology", Applied Polymer Sy posia, _o. 14, P.F.

- -

BRUINS, Interscience Publ. (1970) .

The following examples illustrate the invention: Example 1

Twelve g (2 parts) of trimethoxy-n-prαpanol-silane methacryla¬ te (^-methac-^lQxy-propyl-triinethoxysilane) were added to 300 ml of water acidified at pH 3.6 with acetic acid. After agitating for 20 min at rcαn teπperature, 30 g (5 parts) of silica (AERCSΓL-380, DEGUS- SA) were added under violent stirring; the solvent was removed by evaporation and the Charge was dried overnight at 11Q°CΛ5 T rr. A first lot (A) of grafted silica was thus obtained in 92% yield.

The above preparation was repeated using 12 g of triιnethoxy-3- aπύnoprσpyl-silane as the organosilane cαrpound, the same type of silica (but 48 g in place of 30 g) and a water medium at pH 9 (NaOH) . A second lot (B) of grafted silica was thus obtained in 95% yield.

For testing lots A and B of grafted silica, a two coπponents Polyurethane resin (type VERILSC, Pont d'Ain, France) was used, this material co prising a polyol component (Cü-53-300) and a polyisocya- nate hardener component (DÖ-436) . The polyol σoπpcnent is a 1:1 mix- ture of a monomer and an inert solvent (50 parts by weight of a so¬ lid with 50 parts by weight of a solvent) . To this, one adds 50 parts by weight of the hardener. The application is done by spraying (if dilution is necessary, one uses butyl acetate) . F r the tests, 80 g of the polyol ooπpcnent were used to which were added 16 g of grafted silica (lot A or B) . The σαrponents were mixed for 2 hrs αi a planetary milling device (a device in which the jars also containing milling balls are simultaneously spun and rotated in a circular fashion) , then to 96 g of the dispersion thus obtain- ed were added 40 g of hardener. Coating c rpositions, respectively A and B, were thus obtained.

Coatings with the cαπpositions of thickness about 50-100 -u were applied on Square polished steel plates of about 10 cm on the side and allowed to harden for 1 hr at 60°C. A σcntrol sample (C) was pre- pared identically but using no Charge in the cαπposition.

The coating sairples were subjected to the TABΞR (ASTM) abrasiαi test desσribed in the international application No. PCT/EP82/00004.

O PI

The results after 500 and 1000 abrasion cycles are listed in Table I below and given in terms of mg of coating lost during best.

TABUS I

Results (mg)

Sai le % of silica 500 C 1000 C

A 20 8.7 25.2

B 20 6.8 15.3

C — 7.1 23.0

The results show that the wear rate of saπple B is significant- ly less than that of the control (no silica) and that of saπple A (containing silica grafted with groups which do not co-polymerize with the mcnαners of the resin used in the coating) . This example shcws that even if the incorporation of a mineral Charge in a hydro- phobic resin is facilitated by using particles bearing organophilic groups, marked i-iprovement in the physical properties of the coat- ings are observed only in the case where said organophilic groups can also co-polymerize with the resin monαners and become intrinsi- cally bound to the coating matrix.

Exaπple 2

The sa e general prccedure as for Exaπple 1 was used with the following reagents: Silica: AEROSIL-380 30g; Siloxane: V-glyσidyl- oxypropyl-tr:Lmet-X-«ysilane 12 g; pH of hydrolysis: 3.6.

This grafted silica was incorporated into the first σoirponent (1, epoxy σoπpcnent) of an epoxy-resin labelled SUPER JALTONTT (manu- facturer: JA QT, Switzerland) at a level of 10 g of silica for 40 g of (1) ,i.e. 20 g of a -rcnαner plus 20 g of a solvent. Thai 40 g of a second coirpcnent (2, amine hardener) was added to the ixture (50 g) of silica and the first c nponent. After thoreugh mixing, the co - position was applied on a steel plate as an approximately 50 U layer (saπple E) which was allcwed to harden for 1 hr at 80 ^β C. Another sam¬ ple (D) was prepared identically but for the use of silica grafted

- -

with 3-methacryloxy-propyl-trihydroxysil-_ne already used in the case of saπple A in Exaπple 1. Moreover, a control saπple (F) was also prepared with no silica.

The sanples were subjected to the TABER test like in Exaπple 1 and the results are listed in table II.

ΆET_E II

Saπple % of silica Hesults (2000 C) (mg)

D 20 21

E 20 17

F — 27

The most favorable results are again obtained when using as the

Charge a silica bearing, grafted cn the particles, groups which are copolymerizable with the mcnomer of the resin.

When using a Charge of silica having grafted thereon an a ine carrying chain (the silica used in lot B of Ξxairple 1) and incorpo- rating this Charge to the hardener (2) of the present epoxy resin, results obtained frαm a coating made with this composition were quite coπparable to that fron sample E above.

Ξxaπple 3

The materials used in the following exaπple are defined below: Charges: Si0 ₂ (Aerosil-380 fron DEGUSSA; surface area 390+30 m g average particle size 7 n )

A1 ₂ 0- (Aluminum σxide-C fron CEGUSSA; 100+15 20 nm) Ti0 ₂ (Titaniu dioxide P-25 fron DEGUSSA; 50+15 m ^{2 *} ?. 30 nm)

Grafting coπpounds: Y-MPS ( -rtEthacryloxypr pyl-tr-_methoxysila- ne; ingredient A-174 fron UNION CARBIDE) -EPS ( T-epoxypr opyl- tr ime thcxys ilane ; in¬ gredient A-187 frcm UNICN CARBIDE) Y-APS ( -amincprσpyl-tr ime hoxys ilane; A-1100 frαn UNION CARBIDE)

Preparation of the corresponding trihydroxysilanes:

The hydrolysis of the trialkoxysilanes was perfor ed at 25°C in a stirred 1 liter reactor containing 5.00 ml of hydrolyzing aque¬ ous medium (water + required a ount of acid or base to adjust pH) and to which was added such a quantity of trialkαsysilane to obtain after hydrolysis a 2.5% by weight concentratiαi of the trihydroxy- silane in the medium of hydrolysis. The pH and reaction time were as follows: tf-MPS, 3.5, 40 min; -EPS, 6, 40 min; -APS, U, 3 hrs. Grafting of the charges: Grafting was effected by adding 50 g of the mineral charges to the above 500 ml of aqueous raedium containing the trihydrσxysilane and hαmogeπeizing in a "PRESTO MTT. " homcgenizer for 10 min. The weight ratio of grafting reactant to Charge was 12.5/50 = 1/4. The isolaticn of the grafted Charge was carried out by spray-drying in hot air (160°) with a "MINI SPRAY HO" apparatus. Flow rate 600 r_αrain; teπperature of the spray enclosure 83-86 ^β C.

For testing the effect of incorporating the grafted charges in¬ to organic coating coπpositions, the following lacquer ba≤es were selectεd:

1. ASEOL M-71, a two cαrponent unsaturated polyester type resin for hörne appliances obtained from ASΞX A.G., 3001 Bern, Switzerland. For preparing the coating ccπposition, the raanufacturer recαmends to mix 4 parts of hardener (MESK-P-20, coπpcnent B) with 100 parts of uπpolymerized resin (coπponent A) . Curing ccnditicns, 3 hrs, 80°C. Solvent acetcne. Cperaticns under nitrogen. 2. SUPER ÄLTCNIT, a two cαrpcnent lacquer base epoxy-resin for floor or furniture coverings obtained from JALLUT SA, CH 1030 Bus- signy, Lausanne. Recoπmendations for preparing the coating σoπposi- tions: 1 part of coπpαnent (A) for 1 part of coπpcnent (B) ; curing for 48 hrs at rcom te peratüre. Thinner: JATJJr THINNER. 3. PO-___OREΠ-HANE 53300, a two coπpcnent olyurethane base resin for the autαrotive industry fron VEBIZAC CO, F-01 Pont d'Ain, Fran¬ ce. The coating σoπposition is prepared by ixing 100 parts of the main coπpcnent A with 50 parts of hardener (D_>-436, cαπponent B) and 0 to 5 parts of thinner (D-4064) . Baking: 1 hr at 60°C. 4. A proprietary foπrula for a photosetting ccπpositicn cαrpris- ing as coπpcnent A, 33.3 parts by weight of EBEESYL 220 (an olefinic prepolymer fron UNION CH ϊIQUE BΞLGΞ) and 66.6 parts of diethylene-

glycol diacrylate and as coπponent B, four parts of photoinitiators (DAROCURE 1173, 2 parts - IEGACÜRE 184, 2 parts) . Films of such ccm- position are cured by 15 - 20 see exposure under 80 W/αn UV light in air. Incorporation of the graft charges into coating cαnposition:

For i-ncorporating the graft filier into the test resin cαrpo- sitions, a calculated amount of Charge was selected and mixed with coπponent A (the ain coπponent of the cαrposition) for 4 hrs at rσαπ teπperature in a micrcball mill (size of beads 1.5 - 2 mm) , when cal- culating the amount of Charge, account was taken of the seccnd com- penent of the resin to be subsequently added (see Table III) . When, the dispersion was hαrcgeneous eneugh and the Charge particles re- duced by grinding to a size of about 1-3/u as determined with a ERICΞ- SEN-GAUGE, it was filtered on a 15 u sieve and the beads were wash- ed with a little solvent. The viscosity of the dispersion was measur- ed with a viscometer RHEC3MAT-15, EPPR1-TH-. COMRAVE-S __, Switzerland.

The results are listed in Table III below. In Table III, the follcwing data are also provided: the type of charges used, the graft¬ ing coπponents (nene indicates controls) , the type of resin, the per- cent by weight of grafted Charge incorporated relative to total weight of resin and grafted Charge and the total percent by weight of solids (resin + mineral particles) in the dispersion (when this percent is not 100, it indicates that coπpcnent (A) already σontained solvent; also the presence of solvent may result fron the washing of the beads at the filtration stage) .

TABLE III

Ξxp. Type of Grafting Test Charge in Total solids Viscosity of No. Charge silane resin test resin in dispersion dispersion

(Nö) (% b.w.) (% b.w.) (cP)

1 Siθ2 -MPS 1. .2 64.4 160

2 Tiθ2 .34 64.4 110

3 AI333 .2 48.1 45

4 Si0 ₂ 4. .2 100 410

5 A13D3 It .2 100 350

6 Si02 -E s 2. .33 48.9 40

7 Ti02 .52 68.0 65

8 A1203 .33 49.3 35

9 Si02 <T-APS 3. .33 46.5 250

10 Ti0 ₂ .47 47.8 200

11 A1203 .33 41.2 20

12 Siθ2 none 2. .33 15.8 Ωiixotrop.

13 π

T2O2 .52 45. 11

14 AI2O3 11 .33 15.8 π

15 ncne 1 0 100. 1000

16 ncne 2 0 50. 98

17 none 3 0 50.6 120

18 none 4 0 100. 70

The above results shcw that, due to the grafting of organcccm- patible groups on the Charge particles, it was possible to add rela- tively large proportions of charges or pigments (Ti0 ₂ ) to the resins without experiencing unusually high viscosity coπpared to the unload- ed resins. In the absence of such grafted organic groups, the char¬ ges iπparted thixotropic properties to the resins. Segarding appli- cations in the paint and lacquer industry, it was noted that the sam- ples containing the Ti0 ₂ white pigment had an opacity and covering capacity π ch superior to that of coπparable ccπroercial paints con¬ taining the same pigment whether applied by spraying or coating by hand.

Testing of the cured fil s

The dispersion obtained after hαrcgeneously dispersing the graft charges in coπpcnent A of the resin coπpositions (see prcperties re- corded in Table III) were ccπpleted accordi g to manufacturer's speci- ficaticns by adding coπponent B and mixing vigorously with a stir- rer. In doing so the composition acquired a concentration by weight of mineral Charge relative to the organic remainder of the composi¬ tion of 20% in the case of the Si0 ₂ and l ₂ 0 ₃ charges and 34% in case of the TiO_. The compositions were spread into films by applying on 10 x 10 cm ircn plates with a hand coater. The films were cured ac¬ cording to the manufacture 's directions (see previous sections) and subjected to the TABER abrasiαi test in a TABER Abrader, Madel 505. Details on the test are given in PCT/EP62/00004. To accelerate the test, the rotating wheels were loaded with 1 kg each instead of 0.5 kg as usual.

The results in Table IV below show the weight loss (mg) after a given number of cycles. The sign "d" indicates a destruction of the film under test.

TABLE IV

Exp. kind of kind of loss after _o of cycles

NO resin Charge 25 50 100 150 200 400 600 1000

1 1. ncne — 10.6 18.7 24.8 d

2 II Siθ2 — 6.1 14.1 d

3 II AI - 3 4 9.5 d

4 II Tiθ2 3.9 10 16 d

5 2. ncne — — — — 5.1 10.6 — 28.7

6 Siθ2 — — — — 4 9.3 — 24.3

7 3. none — — — — 9.5 16.1 23.2 33.3

8 Siθ2 — — — — 5.8 12.6 17.1 24.1

9 Al £3 — — — — 5. 6 d

10 Tiθ2 — — — — 8.8 d

11 4. none — — — — 3.3 6.2 — 15.5

12 Si0 ₂ 0.8 3 — 8.2

13 AI 3^3 1.9 4.7 12

O PI

- lβ -

The above results show that in several instances the ineorpo- ration of the grafted Charge brought out significant iπprovements to the properties of the films.

Example 4

As the Charge, i0 ₂ was selected and was reacted with Ϋ-EPS in the same ccnditicns and with the same proportions as in Exaπple 3.

Then a quantity of the grafted TiQ- was added to an amount of SUPER JALTCNIT Resin base under the condition of the previous Ξxaπple to provide a weight ratio of i0 ₂ to TiO _j plus resin defined in Table V below. Two ccntrαl saπples iiicorporating ungrafted TiC were pre- pared under the same ccnditicns. Before applying the resulting coπpo- siticns, solvent (JALLUT T ENNER) was added to provide a viscosity of 47 cP in all three saπples. The percent of solvent used is cal- culable by substracting frcm 100 the values in percent by weight of Ti0 ₂ + resin given also in Table V. The diluted coπpositions were applied as thin films (100/u wet) with a hand coater (V.E.L. , Research Equipment, CO, London) on a sheet of black polyethylene film (load- ed with carbon black) whose diffuse reflecticn density is 1.92. Then the films were cured while solvent evaporated according to manufac- turer's reccππendations for the resin, and the percent reflectance was raeasured with a MACBETH Quanta Log Densitαrεter. The results are shown in Table V. These results show that the quantity of Ti0 ₂ which could be added to the resin to obtain the same viscosity was much greater when using grafted Ti0 ₂ than with ungrafted iO _j . The cort- sequences were that the σptical quality (covering power, external aspect) of the coatings were drastically iπproved σver that contain- ing ungrafted TiO«.

TABLE V

Ccmposition Cured coating

Saπple of Ratio of TiC ^* 2 Total solids External Reflectance Diffuse τiθ2 over Tiθ2 Tiθ2 + polyπer A_=pect (%) reflection

+ resin (% by w.) density

Graf ed 0.518 57.5 shiny 52 0.28

Ungrafted 0.518 34.5 Dull 35 0.45

(control)

Ungrafted 0.416 36.5 Dull 20 0.72

(control)

It was also shown that the dispersion of graft filier was stable with tirte while the dispersion of ungraft filier settled after 48 hrs.