AU603908B2 - Subbing layers for photographic elements and photographic elements incorporating such layers - Google Patents

Description

V

S F Ref: 648l16 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICAT16W 08

(ORIGINAL)

FOR OFFICE USE: Class Int Class 0.

00 o .01 o Ia a Complete Specification Lodged: Accepted: Published: Priority: Related Art: a., of Applicant: Address for Service: Minnesota Mining and Manufacturing Company 3V Center Saint Paul Minnesota 55144-1000 UNITED STATES OF AMIERICA Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 3' Market Street Sydney, New South Wales, 2000, Australia Complete Specification -for the invention entitled: e-~xx OCk, r, 0 I~ U U LI If1~l~UP~ The following statement is a full description of this invention, including the best method of performing it known to me/us 4

ALIA

4:i X- i-Y. 1 r 1 SUBBING LAYERS FOR PHOTOGRAPHIC ELEMENTS AND PHOTOGRAPHIC ELEMENTS INCORPORATING SUCH LAYERS BACKGROUND OF Tij INVENTION 1. Field of the Invention The present invention relates to subbing layers for photographic elements and to photographic emulsions on substrates having such subbing or priming layers thereon, 2. Background of the Art The construction of silver halide photographic elements has become an art that is an amalgum of many different sciences and technologies. Such varied disciplines as polymer chemistry, crystallography, physics, electrostatics, dye chemistry, coating technologies, and the like have to come into focus to produce what is to the consumer a simple snapshot.

Two complex problems that have traditionally been of concern to the o, 15 photographic industry are adherence of the photographic emulsions to the substrates of choice polymeric substrates such as polyester, O 0 S' polyolefin, or cellulosic ester bases and polymer coated paper bases such as white pigment filled polyolefin or polyvinylidene chloride coated paper). Another problem, particularly in high image content film which is 20 processed mechanically is the development of static or triboelectric charges in the film which create spurious images.

Many different compositions, combinations of layers, and treatment of substrates have been proposed to effect better adhesion between emulsion layers and sLastrates as is evidenced by the number of patents in this 5 technical area. A sampling of these patents include U.S. Patent Nos.

3,271,345, 2,943,937, 4,424,273, 3,791,831 and the like. A great amount of 6 P work has also been directed in -2the photographic sciences to the elimination of electrostatic charges on photographic film. Examples of thq diverse work done in this area includes U.S. Patents 4,582,782, 3,884,699, 3,573,049 and the like.

Assorted handling problems adhering of layers) are often addressed by the use of particulate matting agents in backside coatings or surfaue layers of photographic elements. Also sensitometric effects lightscatterin~j) are achieved by the use of particle-containing layers in photographic elements. These uses of particulate containing layers shown in U.S. Patents 4,343,873, 4,144,064, 3,507,678, 4,022,622 and the like.

0 0 0 Typical photographic supports comprise a base o "Q 0 0material polyester, cellulose triacetate, or paper) 015 with a subbing layer on at least one surface to assist in 00 the adherence of the gelatin layers, including the emulsion a 0 0 0020 0 00 over a substratenwheneetheosubstate hs t leoogasthon 00 polymeric surface to which is adhered a layer compilsing a gelled or hydrolyzed network of inorganic particles, pre- 0 00.ferably inorganic oxide particles, containing an ambifunctional silane.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to photographic elements. These elements comprise a substrate having at least one silver halide emulsion layer on a surface thereof.

A surface with an emulsion thereon is hereinaftier referred as a major surface of the substrate. The silver halide emulsion generally comprises silver halide grains (also -3referred to as crystals or particles) carried in a waterpenetrable binder medium of a hydrophilic colloid. It has been recently found that the use of a gelled or hydrolyzed network of inorganic particles, preferably oxides, as a layer on a polymeric surface provides an excellent subbed (or primed) substrate for photographic emulsions It was found that this gelled particulate layer is capable of providing one or more excellent properties to the photographic element including, but not limited to antistatic properties, ease of coatability of the particulate layer, photoinertness (harmless to the photographic emulsion and 00 ooo°°oooits properties), adhesion (both wet and dry, to both the substrate and the emulsion layers), and reduction in 15 spec~alar reflectance antihalation properties).

However, it has been determined that wet adhesion can be o0 ooo weak during development processing. It has been hypothesized that the bond between the gelled network and the gelatin is an acid/base bond. During the elevated pH 20 conditions of development, this bond is sufficiently a 00 00o weakened so that other materials in the emulsion will como0 o 0 pete with the gelatin for reaction with sites on the sol-gel coating. This can weaken the bond between the gelatin 01o olayer and gelled network layer. Lifting or separation of 0 &a the layers can result.

It has been found according to the practice of the present invention that the addition of an ambifunctional silane into or onto the gelled network will produce a strong chemical bond between the inorganic particles and the gelatin.

The term ambifunctional silane means that the compound has reactive silanes on one end of the molecule and a different reactive species capable of reacting with a photographic hardener for gelatin or directly with gelatin.

This second functionality enables the compound to react with the inorganic particle (through the silane group) and also -4react with the gelatin (reacting with the gelatin harhinwhich also reacts with the gelatin). Amongst the preferred second functional groups on the compound are amino grou and epoxy glycidyl) groups. The second functionality may be present as a single functional moiety or may be present as a multiple number of such groups.

A formula that may be used to represent many of the ambifunctional silanes of the present invention is (Q)-R-Si(OR 1 )3 wherein R' is alkyl or aryl, R is an organic group with external bonds or valences, S 15 n is 0, 1 or 2, and Q is a moiety reactive with photographic hardeners or directly with gelatin alpha-amino acids).

Preferably RI is alkyl of 1 to 10 carbon atoms and most preferably 1 to 4 carbon atoms. R is preferably an aliphatic or aromatic bridging group such as alkylene, arylene, alkarylene, or aralkylene which may be interrupted with ether linkages (oxygen or thioethers), nitrogen linkages, or other relatively inert moieties. more preferably R is alkylene of 1 to 12 carbon atoms, preferably 2 to 8 carbon atoms, with n equal to 1. Q is preferably epoxy, or amino, primary or secondary, more preferably primary amino.

Where previously indicated that the second functional group may be present as a multiple number of such groups it is meant that the moiety may include moieties such as N,2 -(CH 2

)-NH-(CH

2 2 -NH-(CH 2 )3 2 NM-(C11 2 (NH 2 zC-C 2

-C

(N

2

)--CHI

(NH -CH/ and the like.

The substrates of the invention may comprise any material having at least one polymeric surface which is to be used as the major surface of the substrate.

The silver halide photographic emulsions which are used in the present invention, as protective colloids, in addition to gelatin, include acylated gelatins such as phthalated gelatin and malonated gelatin, and may also contain cellulose compounds such as hydroxyethyl cellulose and carboxymethyl cellulose, soluble starch such as dextrin, 0 0 15 hydrophilic polymers such as polyviyl alcohol, polyvinyl pyrrolidone, and polyacrylamide, plasticizers for 0 0o dimensional stabilization, latex polymers, and matting 0 agents can be added. The finished emulsion is coated on a 0 0 suitable support.

Supports which can be used include films of syn- 00,. thetic polymers such a polyalkyl acrylate or methaccylate, polystyrene, polyvinyl chloride, partial formalation polyvinyl alcohol, polycarbonate, polyesters such as polyethylene terephthalate, and polyamides, films of cellulose derivatives such as cellulose nitrate, cellulose acetate, cellulose triacetate, and cellulose acetate butyrate, paper covered with x-olefin polymers or gelatin (a natural polymer), for example, and synthetic papers made of polystyrene; that is, any of transparent or opaque support commonly used in photographic elements can be used. Primed polymeric substrates are also useful, including, but not limited to, gelatin-primed polymers gelatin on poly(ethylene terephthalate)), and poly(vinylidene chloride) copolymers on polyester. Other primeLs such as aziridines, acrylates, and melamine-formaldehyde are also known. This includes polymeric materials loaded with pigments and particulates such as titania to improve the white background of the image and to provide antihalation or other nsit metric effects.

The substrates of the invention may be used with any type of photographic silver halides including, but not limited to silver chloride, silver bromide, silver chlorobromide, silver iodochlorobromide, silver bromoiodidL aid silver chloroiodide grains, which may be in any of the many available crystal forms or habits including, but not limited to cubic, tetrahedral, lamellar, tabular, orthorhombic grains, etc.

Soluble silver salts and soluble halides can be reacted by methods such as a single jet process, a double °o jet process, and a combination thereof. In addition, a SOO procedure can be employed in which silver halide grains are g1 formed under the presence of an excess of silver ions (a so-called reverse mixing process), A so-called controlled o 0Q double jet process can also be employed in which the pAg of the liquid phase wherein the silver halide is formed is kept constant. Two or more silver halide emulsions which have been prepared independently may be used in combination with oo 0 each other.

O Soluble salts are usually removed from the silver halide emulsion after the precipitate formation or physical ripening of the silver halide emulsion. For this purpose, a noodle water-washing method can be employed in which the soluble salts are removed by gelling the emulsions. A flocculation method utilizing inorganic salts containing polyvalent anions, anionic surface active agents, anionic polymers or gelatin derivatives can also be used.

Although so-called primitive emulsions which are not chemically sensitized can be used as the silver halide emulsions, the silver halide emulsions are usually chemically sensitized. This chemical sensitization can bo carried out, for example, by the methods as described in H.

SFrieser ed., Die Grundlagen der Photoqraphischen Prozesse mit Silverhalogeniden, Akademische Verlagsgesellschafti pp.

675-734 (1968).

I.

That is, a sulfur snsitization mtw suJ..ur-containing compounds capable of reacting with al: gelatins and silver (e g, thiosulfates thiourea s, fit: ca t~o compounds, and rhodanines) a reduction sensitization methcd using reducing substances s tannous salts amines, hydrazinQ derivatives, formamidinesulfinic acid, and silane compounds), a noble metal sensitization method using noble metal compounds gold complex salts, and metal complex salts of Group VIII metals, such as platinum, rhodium, iridium, and palladium, of the Periodic Table), and so forth can be used singly or in combination with each other.

The sulfur sensitization method is describe-d in detail, for ex<ample, in U.S. Patent Nos. 1,574,944, 2,410,689, 2,278,947, 2,728,668 and 3,656,955; the reduction sensitization method, in U.S. Patent Nos. 2,983,609, 2,419,974 and 4,054,458; and the noble metal sensiti2zation method, in U.S. Patent 1,os. 2,399,083, 2,448,060 and British patent No. 618,061.

In photographic emulsions which arc. usedl in the present invention may be incorporated various compounds for the purpose of, preventing the formation of fog during the production, storage or photographic processing of the light-sensitive material, or stabilizing photographic performance. That is, many compounds, known as antifoggantr, or stabilizers, such as azoles benzothiazolium salts, nitroimidazoles, nitrobenzimidazoles, chlorobennimidazoloo, bromobenzimidazoles, mercaptothiazoles, mercaptobonnothiaaoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, and 3 0 mercaptotetrazoles, (particularly oole), mercaptopyrimidines, mercaptotriazines, thioketo compounds oxazolinethione), azaindenes triazaindenes, tetraazaindenes (particularly d.-hydraxysubs ti tuted- 3, 3a, 7) tetraa" aindenes) and poenta- 3 5 azaindenes), benzenethiosulfonic acid, benz.enesulfinic cid, and benzenesulfonic acid amide can be added.

Typical examples of such compounrls; anl mpth,,rA C'fr utsing them are described, for example, in UJ.S, Patent Ns 3,954,474, 3,982,947 and Japanese Patent Publiciaticon o 28660/77.

The photographic emulsion layers of the ligjhtsensitive material of the present invention may contain polyalkylene oxide or its derivatives ethers, ooters and amines) thioether compounds, thiomorpholines, quaternary ammonium salt compounds, urethane derivativeo, urea derivatives, imidazole derivatives, 3-pyrazoZ~idcneo, hydroquinono or its derivatives, and the live for the Vurpose of increasing sensitivity or contrast, or accelerating development. For example, compounds as described in U.S.

Patent Nos. 2,400,532, 2,423,549, 2,716,052, 3,617,280, 3,722,021, 3,808,003 and L3ritish Patent No. L,488,991 can be 9 0 0 s binders or protective colloids to be utsedl in 9 99 sensitive m'aterial of the present invention,~ it is advantageoos to use gelatino. In addition, other hydrophilic 090colloids can be used. For example, proteins such asgelatin 00.09,derivativeG, graft polymers of gelatin and other polymers, albumin, and casein, sugar derivatives such as cellulose derivatives hydroxyothyl cell.ulose, carboxymethyL cellulose, and cellulose sulfate), sodium alginzata and starch derivatives, and various synthetic hydrophilic polymeric substances, homopolymers or copolymers, sC'z'h asG polyvinyl alcohol, polyvinyl alcohol partial acotal, poly (N-vinyl )pyr rol idono, polyacrylic acid, polymotliacryLic 38 acid, polyzacrylamide, polyvinyl imidaoole, and polvinyl pyrazole can be used.

The light-.sensitivo material o~f thn 1tresei~nt inuvfntion is particularly effectively used as a black-and-white reflection light-sensitivo material which Li, to) bt subjoctcd rapid processing. Zn addition, it (.an b e used as, an X-ray recording light-sensitive material, rh t,")mehan ic,process light-sensitive material a 'light-.sensitive materiaT c be e 4n a facsimile system, etc. and further, as a multilayer, multicoior photographic light-sensitive material having at least two different spectral sensitivities.

S The multilayer, multicolor photographic material usuallCy Comp'IseL)C a support, and at least one red-sensitive emulsion layer, at least one green-sensitive emulsion layer and at least one blue-sensitive emulsic~q B ayer onl the support, The order In which the above layers are arranged can bechse aprpiately, Usually the red-sensitive emllsionl -ae cc-tins cyan dye forming couplers, the green-sensitive emu1Llsion layer contains miagenta dye forming couplers, and the blue-sensitive emul slon layev contains yellow dye forming Couplers, In some case: other cornbina iocns can be employed, Even in tile Case Of thle MUltilayer, miltclcfcr photographic material the effects of thle present lnverLtlnn are exhibted significantly in a reflection light-sensitive matericil s niSpectral sensitizing dyes may be used in one or3v s~rl~ver h AWiE? emulsions useful on the subbed substrates of thle present inventlcor T hes o sensti ng dyes are well known in the art to Increase the sens it1:.atton of c silv Pr halide grains to Various portions of thle electromagnetic such as thle ultraviolet, blue. green, yelliow, orange, red, near infrared,, and infrared. These dyes may be used singly or in combinatio:n with other dyes to sensitize the emulsionz.

The substrate of most preferred form ot" the Inventicon bear:- a comprising a continuous gelled network of inorganic metal oxide particles, the network containing an ambifUnctional silane. The parttcles prefpebl have an average primary particle size of less than about 500 or IM) A. As used herein, the term "continuous"~ refers to covering thle surface of th e substrate with virtually no straight-line penetrable discontinuities or gaps In the ireas where the gelled network Is applied. However, the layer may be and m~ally io porous, without ognIflcant stratht-ltne V;ores or gaps 04 RLF/l lG2h in~ the layer. The t'etm ljull-l se Lw'vk t e fe rs a.

aggregation of colloidal partirdes linked together to EOLM I~ Porous three-dimensionalI n et wo rk. Generally all of or thp majority of linkages are fr:om thu material of the particler.

each other and to the silano, bnt some binder such as ut, to abouit 5'z by wegtotemtl oxide of gelatin may aln-1 Le present, The term "porous" refers to the presence of voids between the inorga- nic metal oxide particles created Ithe packing off the metal Oxide particles. The term "primav par1ticle se"refers to the average si-n f unagglomeratedi single particles of inorganic, metaloid.Tetr Caparticle" includes spherical, non-spherical, and fibrillair Kp)a-rticvulate arrangements. Zff the ambifunctional silanre i3 added to an aqueous metal oxido sol before 3oa ting, then th ailane will. lie hydrolyzead iat,' the positions, described as JOR at page line ~,subst tuting hydro;:y groups 1,-v th~o WARI groups. For example, a triothoxysilane will -,Ime trihydroxysilanp. In solittiron with the metal o xirlf particles, the hydrolyze'd silafue molecuiles, may asoci.-ato ,0 %ith the metal oxide particles by "ofxano" 1)onding i reversble fshion j SiOI-1 11OI(partileiO1pricel Az the solution ia dried into a coated layer, it it, expected that most of the hydrolyzeId silano molecules wilbecome associated with metal oxido particles throucth ixnc a~bonding susch that they cannot be washed <zt tth by a simple water wash, The presence (if tho nilano~ molecules does not prevent the gelled particleI netw,,rk from gaining cohesive strength, although the tine r' to gain cohesive strength may bo ineceaseod.

coating should be, thicker thana a ne aro0 pa rt icl Ies Preferably the coating c7ompvi,.Lun a hrns egual to or greater than three oIverager- partiJt amu., and mere p refEnvably equaL, to or jeoter than &c 'rIl diametern.

The nrilsc h nvn~ op<c which may be transparent. tratislucent, or opaique vioiblo light having at least one polymeric ourfface, anl tcwe rmcl theceon a coating ini the iuzLm ufo~niuospi~ of inorganic oxide particles with an adhesion promotine4o effective amount of an ambifunctional silane. When the coating is applied to transparent substrates to achieve Sincreased light transmissivity, the coated article preferably exhibits a total average increase in transmissivity of: normal incident light of at least two percent and up to as much as ten percent or more, when compared to an uncoated substrate, depending on the substrate coated, over a ranie 16 of wavelengths extending tit least between 400 to 900 nin. nn increase in light transmission of two percent or: mozre is generally visually apparent and is sufficient to producu a measurable increase in energy transmissivity when the ,;ted 0 11 1.substrate is used. Anr increase in transmissivity ic -o peset a wavlenthsinto the infrarod porctiqn o.f the spectrum.

The gelled nn~o~is a poruus cai, voids between the inorganic oxide particles. If thki porosity is too small, the anticef lectance may be ro~dQ.

~gif the porosity is too largQ, the coating iG weakened andw may have reduced adhesion to the substrate. Generally, theo a 0 t'colloidal solution from which the gelled network is obtained 00 io -Apb le of providing porosity of about 25 to 79 voltime petuonf;, preferably about 30 to 60 volume percent vhea 0 $a 5, dried. The porosity can be, determined by drying a suiffcient amount of the colloidal solution to provide a dIried p)roduct sample of about 50 to 100 mg and analyL-ingj the sample using a "Quantasorb' t surface aroa analv,;of i~piab-,! grom Quantachrome Corp., Syosott, 'N.

The voids of the porous coaatiaU pcu-vid4 n~ nultLplicity of subwavelength intersticuo between tho inorQ a n 1'c particles where the index: of reafraction abruptly.. from that of air to that of the coating material. TIhense 3tibwavelength intovs ticen,fwhich aro present throu~ihout ('h (coatin layer, Provide "oatingj whialh may have lult index of refraction of from about 1.15 to 1.40, preferably 1.20 to 1.30 dependin~j on the porosity ot the coiatinj.

When the porosity of -the coatingj is hirfli o.3 about volume percent or more, lower values for th- -Are obtained. when the porosity of the coating volume percent or less, higher values for: the RI q-tre obtained.

The average primary particle size of thr colloidal inorganic metal oxide particles is preferably lesos than about 200 A. The average primary particle size oif the colloidal inorganic metal oxide particles is morn preferably less than about 70 A, When the average particle cz becomes too large, the resulting dried coatinq sracei less efficient as an anti reflection Qoating.

The average thickness of the dried cctiis preferably from about 300 to 10,000 A, more prefecabl.y 800 to 5000 A and most preferably between 900 and 2000 A.Such coatngsproidegood antistatic properties. When the coain thickness is too great, the coating liar; redlucnd adhesion and flexibility and may readily flake offE (1 f'orm powder under mechanical stress.

Articles such as transparent sheet or fi2'_ 00 0materials may be coated on a aingle side or on bolt!,; to ~ncrease light transmissivity, the greatestinrs 3eg achieved by coating both sides.

The process of coating the layer of the 2 invention comprises coating a substrate with a solutIn colloidal inorganic metal ox~ide particles (and prefr-vab!,: the silane at this point~j the solution preferably containing at least 02 or 0.5 to 15 weight perrent tl.

particles, the particles preferably having an avornqp.

primary particle size less than about 500 or 200 r, u preferably less than about 7 0 A, an d dr y in j t le ewn ti I u temperature less than that which degrades thQ stib sttr-tt,' preferably less than about 200"C, more preferably i4: range of 80 to 120 0 C. Tho .oating prKAwides th ,us~V withan average reduction In speculav vofl Ptwior least two perc~ent ovter wav0Fnqths, E 4030 mn 1 -13- Coating may be carried out by standard coating techniques such as bar coating, roll coating, knife coating curtain coating, rotogravure coating, spraying and dipping.

The substrate may be treated prior to coating to obtain a uniform coating using techniques such as corona discharge, flame treatment, and electron beam. Generally, no pretreatment is required. The ambifunctional silane may be added before, during or after coating. It is preferred to add the silane to the coating mixture before coating. If the silane is added after the "gelled network" has been coated and dried, it should be added from a water-containing solution, so that the silane will be in its hydrolyzed form.

The colloidal inorganic oxide solution, a hydrosol or organosol, is applied to the substrate of the article to be coated and dried at a moderately low temperature, generally less than about 200°C, preferably 0 80-120 0 C, to remove the water or organic liquid medium. The coating may also be dried at .oom temperature, provided thu drying time is sufficient to permit the coating to dry S 20 completely. The drying temperature should be less thaa at which the substrate degrades. The resulting coating if; hygroscopic in that it is capable of absorbing and/or rehydrating water, for example, in an amount of up to about to 20 weight percent, depending ,n ambient tempornatur and humidity conditions.

The colloidal inorganic: oxide solution utilized is the present invention comprises finely divided solid inorganic metal oxide particles in a liquid. The oatru "solution" as used herein includes dispersions or tuspensions of finely divided particles of ultramicroscopic ;i; in a liquid medium. The solutions used in the practic this invention are clear to milky in appearance. naorganui metal oxides particularly suitable for use in the uresnt invention are those in which the metal oxide part~fcle:' r negatively charged, which includes tin oxide ;sno, titania, antimony oxide (Sb,0 silica, and alumina-coatueis silica as well as other inorganic metal oxides of 1roups

I

14 IV of the Periodic Table and mixtures thereof. The selection of the inorganic metal oxide is dependent upon the ultimate balance of properties desired. Inorganics such as silicon nitride, silicon carbide, and magnesium fluoride when provided in sol form are also useful in less preferred forms of the invention.

The colloidal coating solution preferably contains about 0.2 to weight percent, more preferably about 0.5 to 8 weight percent, colloidal inorganic metal oxide particles. At particle concentrations about weight percent, the resulting coating may have reduced uniformity in thickness and exhibit reduced adhesion to the substrate surface.

Difficulties in obtaining a sufficiently thin coating to achieve increased light transmissivity and reduced reflection may also be encountered at concentrations above about 15 weight percent. At concentrations below 0.2 weight percent, process inefficiencies result due to the large amount of liquid which must be removed and antireflection properties may be reduced.

S °The thickness of the applied wet coating solution is dependent on the concentration of inorganic metal oxide particles in the coating solution S and the desired thickness of the dried coating. The thirness of the wet coating solution is preferably such that the resulting dried coating thickness Pi from about 80 to 500 nr thick, more preferably about 90 to 200 nm thick.

The coating solution may also optionally contain a surfactant to improve wettability of the solution on the substrate, bu" inclusion of an excessive amount of surfactant may reduce the adhesion of the coating to 5 the substrate. Examples of suitable surfactants include "Tergitol" TMN-6 (Unlon Carbide Corp.) and "Triton" X-100 (Rohm and Haas Generally the surfactant can be used in amounts of up to about 0.5 weight percent of the solution.

The coating solution may optionally contain a very small amount of polymeric binder, particularly a hydrophilli polymer binder, to improve scratch resistance, or to reduce formaton of part 'cu late dust d"uring subsequent use of the RLF/1 coated substrate. Useful polymeric binders include polyvinyl alcohol, polyvinyl acetate, gelatin, polyesters, polyamides, polyvinyl pyrrolidone, copolyesters, copolymers of acrylic acid and/or methacrylic acid, and copolymers of styrene. The coating solution can contain up to about weight percent of the polymeric binder based on the weight of the inorganic metal oxide particles. Useful amounts of polymeric binder are generally in the range of about 0.1 to weight percent to reduce particulate dust. These binders can reduce some of the beneficial properties antistatic properties) of the coatings if used in larger amounts, so that they are not most preferred.

The ambifunctional silane is generally present as 0o at least 0.1% by weight of the solids content of the gelled o oov 15 particulate layer. Preferably the ambifunctional silane is 00 o present as from 1 to 20% by weight of the solids content of °o o o0 the particulaLe layer. More preferably the silane is 0o°0 present as 0.2 to 10% by weight of the solids content of the o0 particulate layer.

o o S20 The following procedures were used in making all samples used in the following Examples.

0 0 0 0 0 0 00 0 00 EXAMPLES 0 00 o o Experimental Method: Each sample described in the attached 25 table is prepared as follows: The sol as received from the manufacturer is diluted with water to the desired percent solids. Then the 00 0 specified coupling agent is added to the diluted so!. The 0 0 0 0 amount of coupling agent is calculated according to the o o000 3 percent weight to metal oxide solids. After addition of coupling agent the mixture is vigorously shaken for 30 sec.

to dissolve the coupling agent. Then, 0.05-.l% wt. of Triton X-100 surfactant is added as a coating aid. This mixture is coated onto an appropriate substrate film by: 1) a 10 cm :X 20 cm sheet of film is placed on a flat surface; 2) a bead of the mixture is drawn across tho te of, the sheet (about 1 milliliter); 3) the mixtuve is oGpead -16across the sheet by means of a #4 stainless steel wire-wound rod; 4) the coated sheet is dried in an oven for about two minutes at 100 0 C. The dried coated sheets are allowed to stand at room temperature for one day or more before further use.

Next, a standard x-ray photographic emulsion is prepared and coated onto the above sheets by: 1) the temperature of the emulsion mixture is adjusted to about 401C; 2) a bead of the emulsion (approx. 2 ml) is drawn across the top of a sol-coated sheet; 3) the emulsion is spread across the sheet by means of a #24 stainless steel wire-wound rod; 4) the emulsion coated sheet is dried at 0 C for about two hours.

0 0 0 9 0 000 15 Adhesion Test Methods: The following method was used to 0 0 test all of the experimental samples for emulsion adhesion.

00 Following the tests described below, each samr .e is given a o oo ograde between zero and 10, according to the approximate percentage of emulsion remaining on the sample. Thus if (of -the emulsion remains the grade is if all of the emulsion remains, the grade is "110".

0 The test method is: 1) a 5 cm x 10 cm portion of the x-ray emulsion coated material from above is immersed in x-ray developer at room temperature for two minutes; 2) the is removed from the developer and, while still wiet with developer, scribed in a cross-hatch pattern with the corner of a razor blade, and rubbed with firm pressure in a circular motion for 24 cycles with a rubber glove-tipped index finger; 3) the sample is washed in cold water and dried; 4) a 2.5 cm x 5 cm portion of 3M #610 tape is affixted over the cz.: .,s-hatched area of the test material and pulled off with a vigorous snap; 5) the sample is graded as described above for emulsion adhesion.

The substrate film used in the examle was 4-,il primed with about 0.04 microns of a poly (vinyl idone chloride) containing terpolymer.

0 -17- 0.50g of a 10% wt. solution of Triton-X-100/H' 2 0 was added to each sol mixture to aid in coating.

Example 1 Four test samples were prepared according to the above method using the following silica/silane coupling agent coating solutions: APS is 3-aminopropyl t r iethoxysi lanle A. 17.2g Nalco 2326 colloidal silica, 82.6g E1 2 0, 0.25g APS silica) B. 17.2g Nalco 2326 colloidal silica, 82.7g 1120, 0.125g APS C. 27.6g Nalco 2326 colloidal silica, 72.Og 2 0,4g APS 150 silica) .0 5D. 55.2g Nalco 2326 colloidal silica, 44.Og 1120, 0.Gg APS silica) Eacoh fully prepared sample was tested for adhesion according 0 0to the described method. The adhesion test results for A, C, and D were all "10" (no failure), the grade for B was o Example 2 00..0 Three test samples similar to the samples A, C, 0 00 and D of Example 1 were prepared, except that no silane 0002 coupling agent (APS) was added.

0 2 A. 17.2g Nalco 2326 colloidal silica, 82.8g H~2 0 B. 27.6g Nalco 2326 colloidal silica, 72.4g 1 2 0 C. 55.2g Nalco 2323 colloidal silica, 44.8g H, 2 0 The adhesion test results for A, B and C were all "O0, (complete failure).

Three further samples were prepared in order to test various types of silane coupling agents. The samples 3swere formulated as follows: A. 27.6g Nalco 2326 colloidal silica, ?2.Og Z120, 0.40g y-glycidoxypropyltrimethoxysilane -18- B. 27.6g Nalco 2326 colloidal silica, 72.Og 0.40g methacryloxypropyltrimethoxysilane C. 27.6g Nalco 2326 colloidal silica, 72.0g 0.40g 3-chioropropyltriethoxysilane The adhesion test results were: Sample A, Sample B, Sample C, These results are in agreement with the expected reactivity of the functional groups with gelatin.

Example 4 Two samples were prepared in order to test the usefulness of organotitanate coupling agents: A. 27.6g Nalco 2326 colloidal silica, 72.Og 0.40g isopropyltri(n-ethylaminoethylamino)titanate B. 27.6g Nalco 2326 colloidal silica, 72.0g oo 15 0.40g di-(dioctylpyrophosphato)ethylenetitanate o The adhesion test result for Sample A was for Sample B, 00 0 0 Exam le 0 0 Three samples were prepared in order to illustrate the use of different sizes/types of colloidal silica: o00 0 A. 16.7g Nalco 1115 colloidal silica, 83.1g H20, 0.26g APS 0o B. 5.0g Nalco 1060 colloidal silica, 94.8g H 2 0, 0.25g APS o0 C. 8.33g Nalco 1034A colloidal silica, 91.Sg ,201 0.25g APS The adhesion test results for Samples A, B and C were all Exampe 6 Three samples similar to those of Example 5 were prepared, except that no APS was used. The adhesion test results wele all Example 7 Twelve samples wore prepared with colloidal retal oxides other than silica: GPS is y-glycidoxypropyltrimethoxysilane.

I

-19- A. 21.4g 0.25g B. 8.33g 91.5g C. 11.4g 0.25g D. 25.Og 0.25g E. 10.Og .0 0.25g F. 17.9g G. 10.4g 0.25g H. 12.5g .5 0.25g I. 11.6g

APS

J. 8.33g Nalco TX-2588 colloidal titania, 78.4g 2 80,

APS

Nalco 1SJ-612 colloidal silica/alumina, H20, 0.25g APS Nalco 1SJ-613 colloidal alumina, 88.4g H 2 0,

APS

Nalco 1SJ-614 colloidal alumina, 74.8g H,0,

APS

Nyacol SN-20 colloidal stannic oxide, 89.8g H 2 0,

APS

Nyacol colloidal yttria, 81.9g H20, 0.25g APS Nyacol colloidal zirconia silicate, 89.4g

APS

Nyacol colloidal zirconia acetate, 87.3g

APS

Nyaco lloidl oo ceric nitrate, 88.2g H20, 0.25g Nalco ISJ-612 colloidal silica/alumina, 91.5g 00 0o o 0 00 00 0 0o o 0 0 0 0 0 0 0 0 0 o at 0 00 HO 0.25g GPS The adhesion test results for Samples A and E were for Samples B, C, D, F, G, H, I and J the results were It is noted that in Samples A and E the colloidal particles are anionic, whereas in all the other samples the particles are cationic.

Example 8 Twelve samples similar to those of xample 7, except that no APS or GPS was used, were prepared. The adhesion test results were all E2mple A siliae-coated sample was prepared using the coating mixture 2B and the above-described preparative method. This sample was dipped into a solution of 0.10% APS in ethanol for 15 seconds and air dried. This was then emulsion coated and tested according to the above procedures. The adhesion test result was "lO".

Example Four silica-coated samples were prepared using the coating mixture 2B and the above-described preparative method. These samples were coated with x-ray emulsion modified as follows: A. 100g x-ray emulsion, 0.05g APS B. 100g x-ray emulsion, 0.10g APS C. 100g x-ray emulsion, 0.20g APS D. 100g x-ray emulsion, 0.40g APS The adhesion test results were: Samples C and D, Sample B, Sample A, Example 11 0o A silica-coated sample was prepared using the o o.O coating mixture IC, except that 0.56g of K&K #1312 gelatin was dissolved in the mixture. This was emulsion coated and oo tested according to the above procedures. The adhesion test oo result was Furthermore the conductive and optical 0 properties of the silica-coated sample were comparable to 0 0 those of silica-coated sample prepared with mixture 1C.

The terms sol-gel and gelation, as they apply to the use of inorganic dispersions of particles in the formation of layers, are well understood in the art. Sol-gels, as Spreviously described, comprise a rigidized dispersion of a :is 25 colloid in a liquid, that is the gelled network previously described. Gelation is the process of rigidizing the solgel. This is often accompanied by extraction of the liquid. Gelation, as opposed to pyrolysis, does not necessarily require the addition of heat as room temperatures and normal humidity conditions will allow gelation to occur. These temperatures and humidity conditions will eventually remove sufficient amounts of the liquid for the colloidal particles to become mroe sol.id.

Heat of course can be useful in speeding up the .liquid extraction process as would jgas flow directed againot or parallel to the sol-gel coating.

I -21- The liquid extracted sol-gel coating (which will generally retain some significant amounts of liquid, e.g., at least 0.1% by weight up to 10% or 15% or more by weight in some cases) can be described in a number of various physical terms which distinguish it from other particulate constructions such as sintered, adhesively bound, or thermally fused particles. The association of the particles in a sol-gel system is a continuous sol-gel network which is known to mean in the art that the particles form an inorganic polymer network at the intersection of the particle as with silica sol-gels), or an inorganic salt system. Bonding forces such as van der Waals forces and hydrogen bonding can form °o an important part of the mechanism of particle association.

0 one ono 15 These characterizations of sol-gel compositions are quite distinct from the use of polymer binders which form a o binding medium to keep particles associated and where the 0 00 0oo° particles themselves do not exert direct bonding forces on 00000 one another.

0 0 As previously noted, the size of the colloid particles in the sol-gel is important. Processes where o 0"4 particulates are ball-milled generally produce particles of o0 no less than about 1 micron. Unless a chemical process is 0 a used to form the particles of smaller size, which agglomer- 25 ate to effectively form large particles which are then ball-milled to break up the agglomeration, the particle size limit of about 1 micron from physical pcocessing tends to hold true.

I| Larger particles also cannot be used in -o~cel I: 30 compositions to form an integral layer by only golation processes. The large particles do not bond with uffici b on strength to withstand any significant abraaion.

Claims (12)

1. A radiation sensitive photographic element comprising a substrate with at least one polymeric surface and at least one photographic silver halide emulsion over said at least one polymeric surface, said element being characterized by the fact that said at least one polymeric surface has adhered thereto a continuous gelled network (as defined herein) of inorganic metal oxide particles containing an adhesion promoting effective amount of an ambifunctional silane (as defined herein), said continuous gelled network and said silane forming a coating thicker than a monolayer of said particles.

2. The element of claim 1 wherein said gelled network of inorganic metal oxide particles comprises a layer having an average thickness of between 300 and 10,000 Angstroms.

3. The element of claim 1 wherein said gelled network of inorganic metal oxide particles comprises a layer having an average thickness of between 800 and 5,000 Angstroms.

4. The element of claim 1 wherein said gelled network of inorganic metal oxide particles comprises a layer having an average thickness of between 900 and 2,000 Angstroms. The element of any one of claims 1 to 4 wherein said inorganic metal oxide particles are selected from the class consisting of silica, titania, tin oxide and mixtures thereof.

6. The element of any one of the preceding claims wherein said ambifunctional silane is represented by the formula: R-Si)0Q 1 n 3 wherein R is alkyl or aryl, R is a bridging moiety selected from the group consisting of alkylene, arylene, alkarylene, and aralkylene of up to 10 carbon ato.is, n is 1, or 2, and Q is a moiety reactive with gelatin hardeners or gelatn.

7. The element of claim 4 wherein said alrbifunctional silano is represented by the formula: (Q)n-R-Si) OR -I -23 wheeinR Iis alkyl or aryl, R is a bridging moiety selected from the group consisting of alkylene, arylene, alkarylene, and aralkylene of up to 10 carbon atoms, n is I1, or 2, and Q is a moiety reactive with gelatin hardeners or golatin. G. The element of claim 7 where R is alkyl of 1 to 4 carbon atoms, a bridging moiety selected from the group consisting of alkylene, arylene, alkarylene, and aralkylene of up to 10 carbon atoms, n is 1, and Q is amino or epoxy.

9. The element of clain, 7 where R I is alkyl of I to 4 carbon atoms, R is a bridging moiety selected frcm the group consistinn of alkylene, arylene, alkarylene, and aralkylene of up to 10 arbon atoms, n is 1, and Q is amino or epoxy. Tho element of clainm 0 wThoroin R is alkylono and Q is primary am n 11. The element of any once of cl(ais 1, 2 or 5 wherein s ,Id- Sub(Strate iS a Polymeric film selecteW from the group consisting of polyester, and primed polyester.

12. The element of clair. 4 Wherein said subs.trate is a polym-eric filn selected from the group consisting of polyester, and lined pciyestor.

13. A polymeric film having on at least one surface thereof La continuous gelled network (as defined herein) of inorganic Metal oxide particles containing an adhesion promoting amount of an ambifunlctlenal,, silane (as defined herein), said contilIuOUS gelled network anl surld silano forming a coating thicker than a mionolayer of said particlLhs. 14, The film of claim 13 wherein said gelled network cf in r ganic P-etal oxide particles comprises a layer. havingk an avelrage tcktoss of 4etween 800 and 5,000 Angstrozr. I~ Thle f ilma of ClIa i n, I I o% 14 whu'-Bm i R(.id C (':6tc e:) Part IclIe s are selIected f rolm the G~C"U'I co'nz i Stl ng of t ilica, titan~c, tinl oxide and mixtures thereof. M~ Thle film of cleir TS cv 'L14 ywjere,,i cat,( Liratca ~aei vepresented by the fornuL a, 4 rR~>O RUK~ -24 wherain RIis alkyl or aryl, R is a bridging moiety selected from -tile group consisting Of alkylene, arylene, alkarylene, and aralkylene of up -to 10 carbon atc n is 1, or 2, and Q is a moiety reactive with gelatin hardeners or gelatin.

17. The film of claim 15 wherein satad armbifumctional silae is represented by the formula: wherein is alkyl or aryl, R is a bridging moiety s ectejd fr t (wr2.Ap c ri~o alkyleno, arylene, alkarylene, and catkylenc, of to 3 ,4carv-c [itcx-s, n is I. or 2, and Q is a moiety reactive will-h gelatin haderter,"c .rla-

18. The film of claim 15 whereIni R i alivl olf l to 4 atens, R I s a bri dgi ng moi ety Gel ected friom the group cons Isti ng -f' alkylene, arylene, alkarylene, aNd Larali-yene cf' ct, tco, 10O 7 o n iis I and Q s amino or epoxy'*"

19. The film of claicr T-V werein IU aIli Lo'I 4 XtL atu-s, R tes a bridging moiety selected from the group ostngf ckylene, arylene, alkaryiee tn ariYin c' ptCl O T !s 1, and tcI amino vr ep 2C A p)hotog rap h i L oei-en r, ci med in i (in. ati jL, tt cor LJuscri bed herei n wi i e-enrp t "nr ne 0 tk.he Fxampltv fw Comparative examplen. polymeric ftim iic defined i ,afir and usani7 defi ned herein with teeec m ~m~e t~ 4Cumpaat.vf, ex 00r. IATEL~ this Tv NT,'TVL[Ih hvw AtUGUS' M'innesota Mining and Manufacturing Compan," Patent Attorneys for the Applicant SPRUSON FERGUSQ4 R4}'I J62h