CA2178841A1 - Ink acceptor material - Google Patents

Abstract

An acceptor material (10) for printing by ink-jet printers forms quick-drying, water-soluble resistant, light-stable ink records with aqueous ink jet inks. The material (10) comprises a support (12) such as polyester film and a coated layer (14) containing a water-soluble mordant that forms insoluble compounds with and immobilizes the dyes of the ink jet inks and a hardened water managing polymer, preferably. hardened gelatin, which contains polymeric beads in an uppermost layer. The water-soluble mordants can high molecular quaternary ammonium, amino compounds, phospholipids, or divalent Group II metal ions.

Description

~Vo 95116561 2 ~ 7 8 8 4 I PCTIUS94114501 INK ACCEPTOR MATERIAL

This invention relates to an acceptor material for irlk printing and, more particularly, to a coated acceptor material for forming water-resistant, light-stable ink records with ink jet inks.
BACKGROUND OF THE INVENTION
Ink jet printing is a non-impact means of producing a pattern of ink droplets which can be used to record digital information. To make a hard copy, the droplets are deposited ontû a ~ a,u~ , fr~nel~ Pnf or opaque support such as film, vellum or paper. Ink jet printers have been used for many years to make l~lullocluul~lc hard copy from computers. A rapidly-growing use of ink jet printers is to generate subtractive color images using a three- or four-color process. The resultant hard copy can be viewed by Ll~ulallli~Cd light using an overhead projector (transparent film); bytransmitted light using a diffuse illuminator (translucent film); or by reflected light (opaque support).
In subtractive continuous tone silver halide color ullutu~l~lly, color images are produced by the aU,u~uOa;~iull of three primary continuous-tone color-intensity-graduated recording layers. In non-continuous tone ink jet color printing, use is made of ~ ,lua~,uuic superposed color-separated dots (so-called halftone images) to create an impression to the viewer of an intensity graduated image. The proper hue, size, and degree of ~ and mixing of the primary color dots -- cyan, magenta, yellow and black -- are necessary for the faithful reproduction of color on the recording medium. Accurate ink jet color image recording thus requires a high degree of coopPr:ltil-n between the ink jet color separation pulses, the ink dyestuffs, and the ink acceptor material.
An irlk acceptor material should be capable of accepting the droplets readily amd allowing them to coalesce, yet should achieve color isolation and separation with high chroma and pure hue without image edge distortions due to poor registration, bleeding, ;

2 1 7 8 8 4 1 PCT/llS9~114501 feathering, or other image quality defects. Acceptor materials for colored inks currently available, however, suffer from rapid fading of one or more of the dyestuffs upon exposure to light. Furthermore, currently available ink acceptor materials can be degraded easily by repeated handling or contact with moist objects As a ~,UlI~ ,U~ ,t 5 of such contact, the moist object often becomes stained with the dyestuffs. Also, because the usual aqueous ink jet inks have relatively low volatility, imaged acceptor materials are typically still wet with the aqueous ink vehicle ~hen emergin~ from an ink jet printer. Images are then most vulnerable and can be altered by smudging or blocking as a c.".~ of print stacking.
PROBLEM TO BE SOLVED BY THE INVENTION
An object of this invention is to provide an ink acceptor material capable of rendering ink jet images which dry rapidly, are water-resistant and light stable, can be 15 handled and stacked without damage to the printing or images, and have good layer clarity and good sheet feeding properties in ink jet printers.
SUMMARY OF THE INVENTION
An acceptor material for inks that contain an ionic dye and an aqueous vehicle comprises a support and an ink-accepting cullllJu ~;Liu~ coated on the support, in that the ink-æcepting rr~nnrc~ rln comprises (a) a water-soluble mordant which, when admixed in excess with the ionic dye in aqueous solution at room ~IIlAu~laLulc, forms a water-insoluble precipitate and a clear, ~ colorless ~u,u~ ai~ulL liquid, (b) a water-absorbing solid polymer, wherein the polymer has been rendered insoluble in water at room t~ laiulc by chemical hardening of the polymer at elevated i~.ll,u~ ulc in an aqueous coating solution prior to coating of the eoating solution, and wherein the polymer is non-reactive with and permeable by the ionie dye, and (c) non-porous, clear, substantially spherical, polymer beads dispersed in the water-absorbing polymer in an uppermost layer of the ink-aecepting rrmror~itirn O 95/16561 2 1 7 8 8 4 1 pf~T~S941l450l

- 3 -In another r~ O~ of the invention, an acceptor material for inks that contain am ionic dye and an aqueous vehicle comprises a support and am ink-accepting ''' ''''I'f'`'l;'''' coated on the support, ~.1,-., ~, ;,. ~l in that the ink-accepting ~l.".l,o~:l;....
comprises (a) a water-soluble high molecular weight amino mordant or a water-soluble 5 ~ nl;l.;fl mordant which, when admrxed in excess with the ionic dye in aqueoussolution at room t~ ,u.,laLul~, forms a water-insoluble precipitate and a clear ~1.l.. -'-- ' Iiquid, and (b) a water-absorbing polymer which is non-reactive with and permeable by the ionic dye.
ADVANTAGEOUS EFFECT OF THE INVENTION
The acceptor material of the present invention exhibits the ad~ uu~ effects of high optical clarity, a rapid drying capability, and good sheet feeding properties.
Fu~ lulc~ it accepts aqueous inks to form images of high resolution and excellent I S stability.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure I shows a cross-section of an ink acceptor sheet of the invention in 20 which the support is coated on one side with the ink accepting cnnnro~itinn and on the other side with amtistatic, curl control, or other functional layer.
Figure 2 shows a cross-section of an ink acceptor sheet of the invention in which the support is coated on two sides with ink accepting ~.... ,1...~, l ;....~
Figure 3 shows a cross-section of an acceptor sheet of the invention in which the 25 support is coated on one side with a dye lUUl~lLillg layer, a vehicle-absorbing layer, and am overcoat layer.
Figure 4 shows a cross-section of another plural layer c..lbodl.~.L of the acceptor sheet of the invention.
Figure 5 is a plot of light stability test results for dyes printed on an acceptor 30 material of the invention and on a cullllu~l~,;ally available material.

WO 95/16561 2 1 7 8 8 4 1 PCTIIJS94114!iOI

- 4 -DETAILED DESCRIPTION OF THE INVEN~AION
The acceptor materials of the present invention are useful as receivers for thermal ink jet printing (bubble jet) or for non-thermal printing. In general, they are i useful in any process for recording ;,.r...",-~i,." or images with inks comprising aqueous vehicles and ionic, water-soluble, colored dyes, such as inks disclosed in U.S. Patents Nos. 5,180,4ZS and 5,183,502, which are ;I.c~ ul~t~l herein by refe}ence. ~ith such inks, of which the dyestuffs typically contain anionic groups such as carboxyl and/or sulfonate groups, the acceptor materials of the invention can provide images of high lO quality, which are resistant to smearing and have excellent light stability. The ink acceptor materials of the invention are especially ~ d by rapid drying, a quality of major importance in ink jet printing because of the high liquid content of the ink 1~ and have excellent clarity and sheet feeding properties.
Acceptor materials of the invention function by ;~ 11 of the lS ionic ink jet dyestuffs and the aqueous ink vehicle. A water-soluble mordant reacts with and imml~hili7Pc the dyestuffs by forming a water-insoluble compoumd or coacervate while a hydrophilic, water-absorbing, solid polymer ~;"...11....,,.~1~ wicks away the ink vehicle from the surface of the acceptor material. The mordant thereby controls the dye deposition and directs the dye movement (locus of dots) within the 20 acceptor material to provide dot separation and, ' -registration, thus r the close-packing and ~. of the dyestuffs. The water-absorbent polymer having spherical, non-porous polymer beads dispersed therein controls the large volume of aqueous ink vehicle (for most aqueous inks, 70-90% of the ~..""l.,A,~,I;~,l,) thus causing a rapid dry-to-the-touch response of the acceptor material with minimal dot 25 beading, spreading and no blocking or smudging of the image. The spherical, non-porous polymer beads distributed at or near the irlk-accepting surface of the material and protruding therefrom contribute to rapid drying amd good sheet feeding whileretaining optical clarity of the material. The result is a rapidly dried, fu~l color ink jet image having excellent chroma amd image resolution and stability and desirable surface 30 properties.

_ 5 _ The present invention includes an acceptor material for inks that contain an ionic dye and an aqueous vehicle, wherein the acceptor material includes a support and, coated on the support, an ink-accepting c~mr~ til~n comprising (a) a water-soluble mordant compound which, when admixed in excess with the ionic dye in aqueous S solution at room l~ aLul~ forms a water-insoluble precipitate and a clear ~--h~tSmti~lly colorless s~ Iiquid; (b) a water-absorbing solid polymer, whereinthe polymer has been rendered insoluble in water at room t~ lUlUI~ by chemical hardening at elevated ~tlll~ Lul~ in an aqueous coating . .,1..~ ;.,., prior to coating it on the support, and wherein the polymer is non-reactive with and permeable by the 10 ionic dye; and (c) non-porous, clear, substantially spherical, polymer beads dispersed in the water-absorbing polymer in an uppermost layer of the ink-accepting romro~iti/~n Preferably the beads have a specific gravity no greater than that of the aqueous coating and have diameters from about 3 to l'i ~m; the ~..,....,1.~l;..,. of the beads in the uppermost layer is about 0.5 to 4 weight percent based on the amount of water-l 'i absorbing polymer in the uppermost layer.
The invention also includes an acceptor material ~ ;a;llg a support and an ink-accepting .. 1.~,~;l;.. " coated on the support, .1.,1,, ~ I in that the ink-æcepting i..,,,,l.~.~;l;..,. comprises (a) a water-soluble high molecular weight amino mordant or a water-soluble rl~ mordant which, when admixed in excess with the ionic dye0 in aqueous solution at room ~tlu~ ul~i, forms a water-insoluble precipitate and a clear liquid, and (b) a water-absorbing polymer wnich is non-reactive with and permeable by the ionic dye.
In acc~,llall.,c with the invention, a novel rnmr~itil~n for forming an ink receiving layer on a support comprises water, a water-soluble mordant capable of25 forming a water-insoluble coacervate with ionic dyes, a hydrophilic hardenable polymer, and a hardening agent in an amount sufficient to harden the polymer at elevated t~ UI~ and render it water-insoluble but water-absorbent at room t~ UI~.
Also in accordance with the invention, a novel imaged ink jet acceptor sheet comprises a support and, coated on the support, a layer containing hardened gelatin and, 30 dispersed therein, a water insoluble coacervate of a water-soluble mordant compound and a water-soluble dye compound. In a preferred rl"l,A.,I;",. .,1 suitable for outdoor display, a transparent, water-absorbing layer of hardened gelatin is coated over the layer containing the coacervate.
~urther in accordance with the invention, a method for making an acceptor sheet5 for inks containing an ionic dye comprises:
a) heating an aqueous soluti~m comprising a hardenable polymer, water, and a chemical hardening agent;
b) I~ heating for a time sufficient to react the chemical hardening agent with the hardenable polymer to form a coating I 0 composition;
c) adding to the aqueous solution or to the coating ~ ." (i) a water-soluble mordaAnt which, when admixed in excess with the ionic dye in aqueous solution at room L.~ Lu c, forms a water-insoluble precipitate and a clear, substantially colorless ~ Iiquid, and (ii) non-porous polymer beads of 3 to 15 m diameter and having a specific gravity not ~ h~tAntiAAIIy greater than that of the coating cAmr~ iti~-n; and d) coating the resulting aqueous I~VlllpVi~ iUl~ on a support.
The ink acceptor material of the invention provides diffusion II~ ....11 of the 20 deposited wet ink dots, the dyestuffs therein, and the liquid vehicle of the soluble dyes.
Surprisingly, the applicants have found that polymers, such as those mentioned hereinafter, when subjected to chemical hardening prior to coating perform the role of absorbing the ink droplets and providing a strong, durable, non-tacky, three-,l;,". ..~;III.AI
matrix for the dyestuff immA~hili7in~ component of the material, i.e., the water-soluble 25 mordant. The polymers employed are hydrophilic and easily swellable by the aqueous vehicle of the inks to wick away quickly said vehicle from the surface of the material, whereby the surface of the acceptor material dries rapidly. Said polymers are transparent and can yield, if desired, a finished surface of high gloss. The solid wicking or water-absorbing polymer is rendered insoluble in the ink vehicle below 50C
by chemical hardening of the polymer in an aqueous medium at elevated t~ UUC

~o 95/16561 2 1 7 8 8 4 1 PCTNSg4/14501 prior to coating of the ~..,,.,l,..~;l;..,- on its support. The hardened polymer is, however, soluble in the aqueous medium at elevated h~ LLul~ above 50C and the composition therefore remains coatable.
The ink acceptor materials of the invention are prepared by coating and drying

5 on a transparent, translucent or opaque sheet or web a layer or layers of the a~plulJl;aL., f,""l,n~ In one . ..,l~ol~ an aqueous coating composition is formed which contains the water-absorbing polymer, a hardening agent, the mordant and non-porous polymeric beads. In addition, the ~ preferably contains a coating aid. The coated layer is dried to form a thin layer in which the mordant is uniformly distributed 10 throughout the water-absorbing polymer matrix and the polymeric beads protrude from the surface of the layer. The total thickness of the dried ink-accepting ~ .l. on the support, whether coated as one or a plurality of layers, is preferably in the range from about I to 25 ~Lm, (although greater Ll-i~,L.~ s can be used), and, most preferably, is in the range from about 2 to 18 ~m. The polymeric beads improve sheet 15 handling and, with the water-absorbing polymer, contribute to rapid drying.
The water-absorbing polymers employed in the materials of the invention have no affinity for the water-soluble ink jet dyes and therefore allow rapid diffusion of said dyes into the ink acceptor material, wherein said dyes are very rapidly imm~bili7~d by chemical reaction with a mordant to form a non-diffusing compound or coacervate.20 The mordant can be distributed uniformly tbroughout the water-absorbing polymeric matrix or it can be mixed with a portion of the water-absorbing polymer and coated in a separate layer above or below the water absorbing layer. When the mordant compound is cationic it forms an ionic bond with water-soluble . u~ .t ;~ dye ~."..l.u...,.l~ such as those disclosed in U.S. Patents Nos. 5,180,425 amd 5,183,502 cited 25 above. The high optical density which ~ , . . ;, the images formed by the acceptor materials of the invention appears to result from the high ~ ;.... of mordanted dye or coacervate at the exposed surface of the mordant, regardless of its coated placement relative to the support.
Although the ink jet inks with which the ink accepting materials of the invention 30 provide such . ' ~ results, are aqueous inks, it should be umderstood that, in addition to water, the ink vehicle can also include hydrophilic organic liquids. In general, the water content of the aqueous vehicle of the inks is in the range from about 30 to 99 weight percent, and preferably 70 to 90 weight percent, the rest being hydrophilic organic liquids such as glycols, glycol ethers, pyrrolidones and cllrfA~t~ntc 5 As is known, such hydrophilic liquids can aid in the delivery of the inks by ink jet printers.
Referring to the drawings, Figure I shows a preferred c~ bud;l~ lL 10 of an acceptor material of the invention comprising support 12 and, coated on it, ink-accepting ~ 14. Support 12 is a sheet material which can be transparent, 10 trAnc~ rnt or opaque. Useful transparent or translucent materials include, for example, poly(ethylene terephthalate), cellulose acetate, pOI~ bul.~ polyolefin, polyvinyl chloride, polystyrene, polysulfone, styrene acrylonitrile (also known as SAN), glass amd the like. Useful opaque sheet materials include paper, opaque filled polyester, polyethylene-clad paper, white polypropylene film and the like. Support 12 can be 15 coated with a ~,ullv~llliollal tie or subbing layer (not shown) to enhance adhesion of ink-accepting ~..",l,. ~,l;.." 14 to support 12, as well as one or more backing layers 16 to control conditions such as static, blocking, curl or color.
Ink-accepting rnmr~itinn 14 comprises a water-absorbing polymer, preferably a hardened polymer such as hardened gelatin, wherein the gelatin may be hardened in 20 solution prior to coating by reaction with a hardening agent. Upon being coated and dried, the polymer forms a matrix which is transparent to light, is insoluble in water at room t,.ll~ L~ , and is resistant to abrasion. The polymer, however, retains itshydrophilic character, is easily swollen by water, is easily permeated by the aqueous ink vehicle and by water soluble dyestuffs, and has no chemical affinity for said dyestuffs.
25 The hardened polymers used in the acceptor materials of the invention are water-absorbing polymers that are so easily swollen by water that they are swellable by up to 400/~ when imrnersed in the aqueous ink vehicle. By this is meant that the volume of the polymer increases by at least about 400% when soaked in water.
A highly preferred hardenable polymer is gelatin. Other preferred polymers 30 include chitosan (discussed more fully hereinafter) and 100 percent hydrolyzed 9 _ poly(vinyl alcohol). Hardenable natural polymers other than gelatin and chitosan that can be used in the materials of the invention include starch, agarose, albumen, casein, and gum arabic. Il~d~lldlJlc synthetic materials include, for example, hydroxy propyl cellulose (e.g., Klucel polymer of Hercules Corp.), ~,a~bu~yl~ yl~ . .IC
5 lattices, poly(acrylic acid), poly(lll.,ill.~lYillyl.,il..,l-co-maleic anhydride) e.g., Gamtrez 169 polymer, poly(vinyl alcohol) and poly(N-vinyl-4-pyrrolidone).
Still another ul~llald~ polymer which is useful as the water-absorbing polymer in the ink-accepting materials of the invention is hardened chitosan. Chitosan is partially dl,a~,~,iyl..~,d chitin. Commercially, chitin is extracted from shrimp and crab 10 shells and l..",~r.,l,.l~d to chitosan to obtain a water-soluble product. Chitosan is a linear biopolymer, specifically a pOly~ac~llalidc which comprises two ".,,"..~ 1N-acetyl-D-~ and D-~ linked by ~(1~4) glycosidic bonds.
Commercial chitosans hâve degrees of ~,a~ ylaiivll between 75 and 95 percent. The viscosity range of commercial chitosans is from lO to lO00 mPa s. A chitosan useful lS in preparing the materials of the invention is available from Pronova Biopolymer a.s. of Drammen, Norway. The chitosam is In~ all~llcd, by heating in aqueous solution with a chemical hardening agent as disclosed herein, for use in the materials of the invention.
As discussed in more detail hereinafter, c- ,.,~ . 14 also has dispersed therein, and ,ul.~L7.. ' .lly at the surface thereof, certain non-porous polymeric beads.
20 These beads provide valuable surface properties while cuilLIibuLillg to ink absorption, but retain the desired clarity of the layers of the inlc-accepting material of the invention.
Ink-accepting c.. ~ . 14 further includes a water-soluble mordant or dye-fixing agent, which is capable of bonding ionically or otherwise with the dyestuffs in ink jet inlcs, to form a water-insoluble, immobile or "~uac~,l v " compound in the 25 acceptor matrix without any significant change in the chroma or hue of the original dyestuffs. By water-soluble mordant is meant a Illul~allLi~lg compound capable of dissolving in water at room t~ a~uL~, (20C) to at least a 10 gm/liter c..l.~...1.~;....
Preferably, the mordant is water-soluble to at least 30 gm/liter at room l~,lll,u~,laLuu~.
Different types of water soluble mordants are useful m the practice of the 30 invention. Certain ~ - "l J ~ l~ that are useful mordants in the materials of the invention immobilize or anchor the anionic dyestuffs of ink jet aqueous inks by forming ionic bonds with the dyes Others bond to the dyes by ~ ,,.."~",~ that are not fully understood. They all have in common, however, the fact that, when tested in the screening tests described hereinafter, they rapidly form insoluble l~c~ dLt;a with the S dye when mixed therewith in aqueous solution at room h~ ul~. One useful type of mordant that forms ionic bonds with the anionic dyes is a water-soluble, cationic polymer having quaternary ~mm~nilmn side chains such as, for example, Ll~yl.~ chloride llydlu~y~LIl~l cellulose (available as Celquat L-2û0 and Celquat 11-100 from National Starch and Chemical Company). Both of the latter are 10 cationic cellulosic polymers; Celquat H-100 has a viscosity of .~ J 600 mPa-s (2% solids in wate~; RVF Brookfield Viscometer, #2 Spindle/20 RPM/21C) and Celquat L-200 has a viscosity of ap~ L~ly 100 mPa s. Another useful mordant that forms ionic bonds is a copolymer of dimethyldiallyl chloride (available as FlocAid 19 from National Starch and Chemical Company).
Still another useful mordant in accordance with the invention comprises a metal ion from the el~.L~v~ ;Liv~ side of the periodic table of elements, preferably, ions of Group 11 metals such as divalent barium, strontium, or calcium. The metal ions are il~C~lp~l.,t~ in the materials of the invention by mixing an aqueous solution of a salt of the metal, e.g., BaCI2, SrBr2 or CaCI2, with the wicking material during formulation of 20 the coating ~.l"l..,~;li.", Useful mordant ~.,.,.l).. ~ "I~ which pass the screening tests described hereinafter and anchor the anionic dyestuffs by ,. ~ that are not umderstood include non-ionic and high molecular weight (i.e., at least about 400 m.w.) amino UWllp~/Ull..b.
They cam be primary, secondary or tertiary amines. These include water-soluble, non-25 ionic polymers containing amino groups, for example, poly(4-vi..yl~ylidill~) which is available from Monomer Polymer Company. Other examples include the propylene oxide based triamines of the Jeffamine T series which are available from Texaco, Inc.
They are prepared by the reaction of propylene oxide with an aliphatic triol initiator having up to about 12 carbon atoms, such as trimethylolpropane or glycerine, ~ollowed ~WO 95/16S61 2 1 7 8 ~ 4 1 PCT/USg4/14501 by amination of the terminal hydroxyl groups. These tri-primary amines are by the structure:
/ ( OCH2 CH ) Y--NH2 -(ocH2cH~y--NH2 CHa \ (ocH2cH~ --NH2 wherein A is the initiator moiety. Molecular weights range from about 440 to about 5000, x, y and z are each positive integers, and x + y + z = 3 to about 85. Preferred examples of such tri-primary amines of the Jeffamine T series include Jeffamine T-403, in which the aliphatic triol is L~ ylol~ , the ClplJlU~ ., molecular weight is 440, and x+y+z is 5 or 6; Jeffamine T-3000, in which the aliphatic triol is glycerine, the ~,IV~illl~.L~ molecular weight is 3000, and x+y+z is ~ t~.ly 50; and Jeffamine T-5000, in which the aliphatic triol is glycerine, the ~ molecular weight is ~000, and x+y+z is ~ IJlU~ ,ly 85.
Although tne above-noted water-soluble amino ~ .v , l~ are non-ionic, they form water-insoluble reaction products with the anionic dyes of aqueous ink jet inks and are useful as mordants in accordance with the present mvention.
Other ~ which pass the screening tests and are useful as water-soluble mordants in the materials of the invention are high molecular weight rh..~rhnlirit~ such as lecithin and also the phn~rhnliri~1 EFA, I,I,n~l.l,nl:l,:.l SV and l.~.n~l.l...l;l.;~l PTC, 25 which are available from Mona Industries, Inc. The latter l~ .l.nl;l: l~ have the structure:

I ~
[R--N--CH2CHOH--CH20]~ P(ONa)y + xCle where x plus y = 3. In such pl~va,ullOlipid~ R is a saturated or ~ r(~ long chain (e.g., of 14 to 22 carbon atoms) ~albuAcu~ido-alkyl (e.g., of 2 to 6 alkyl carbon atoms) radical. In l.l.n~ ,f.l;l~ EFA, R is linnl~rniAorropyl; in rhncrhnliriA SV, R isctr~r~miAnrropyl; in ~ n~ A PTC, R is cul,aulli~v,ulv,uYI.
All ûf the described types ûf water-soluble mordants which pass the screerling test A below are suitable for bonding to, and illullob;li~,ill~ in the matrix, the anionic dyestuffs of ink jet inks. The selection of suitable mordants can be facilitated by the simple screening test in which an aqueous solution ûf an anionic dyestuff which is present in the aqueous ink jet ink is added at room i~lll,u~.aLu~ (20C) to an aqueous solution of a molar excess of the mordant. The rapid formation of a coacervate or precipitate, which can be an oil or a solid, and a clear, substantially colorless ~.. l.. ~l-.,l liquid indicates the suitability of the mordant for use in the ink acceptor materials of the invention. The screening procedure is illustrated as follows:
15 Co ~ ' Screerlin~ Test A - Add dvestuff to mordant solution.
Polvmeric Oll~t~rn~rv Ammonium Salt Test:
1000 picoliters of 5% magenta dyestuff in water is added at room ~lll,u~la~uuc to 20 mg of FlocAid 19 polymeric quaternary ~mm~nil~m salt in water. A gelatinous red precipitate forms. The ~ l Iiquid is clear and colorless.
~minn Com~ound Test 1000 picûliters of 5% magenta dyestuff in water is added at room tclll~,la~llc to 20 mg of poly(4-vill~l,uy~;l;ll~) in 2 ml of water. A gelatinous red precipitate forms.
The :~U,UC~ UI~ liquid is clear.
rl.f.~ nl;l.;A Test 1000 picoliters of 5% magenta dyestuff in water is added at room t~ u~"a~Ul~ to 20 mg of l,l,n~ l SV in 2 ml of water. A gelatinous red precipitate forms. The ~ 1... -~- .l liquid is clear.

~VO 9S116561 2 1 7 8 8 4 1 PCT/USg4/14~01 Poly(N-vinyl-4-DYrrolidone~ Test:
In the same manner the magenta dyestuff solution is added to an aqueous solution of poly(N-vinyl-4-pyrrolidone). No precipitate forms and the liquid is colored.
As shown above, the quaternary ornmnnillnn polymer (FlocAid 19), the amino5 compound poly(4-vi..~lL,yl;.liule), and the ,ullu~,ulloli,u;:i compound all pass the screening test A as useful mordants, but poly (N-vinyl-4-,uyl.ulidu.l~) does not.
Test A is the preferred method for selecting and defining the types of compound that are useful as mordants in the acceptor materials of the invention. In this test, the mordant candidate is in a molar excess. The suitability of the mordant is 1 "...,~
by the rapid formation of a precipitate and by the fact that the ~UU.,~IIa~lL liquid remains clear and ellhr~oAtiAlly uncolored, thus showing that c~hstAntiAIly all of the dye has been mordanted or converted to the insoluble precipate or coacervate.
Test B below is another screening test for mordants. In this test, an aqueous solution of the candidate mordant is added to an aqueous solution of the ink jet anionic dyestuff with which images are to be formed. Since the dyestuff is in excess, the ""I" 1 -'- ' liquid is colored. If the mordant candidate is suitable, it either forms a precipitate; ' 'y or at least forms ~ a turbid suspension which can be A~ntrifil~ d to obtain a precipitate. Thus, either Test A or Test B can be used, but Test A is preferred as a method for defining the suitable mordants because Test A
shows that the dye reacts quickly with the mordant, and Cl~hstRntiAAIIy none remains in solution in the ~ ¦ . Iiquid.
Coa,.... ~ ~A ' Test B - Add ~~~ ' ' to d~estuff solution.
Polvmeric Ouaternary Ammoniurn Salt Test:
To one ml of 5% magenta dyestuff aqueous solution is added 1000 picoliters of a 5% aqueous solution of FlocAid 19 polymeric quaternary A ~- --- ;- ~ salt. A heavy precipitate forms ;.. 1; ~. Iy Amino Compound Test To one ml of 5% magenta dyestuffaqueous solution is added 1000 picoliters of a 5% aqueous solution ol: poly(4-villyll,.yl;di,le). A heavy precipitate forms illllllC.~ y.
S PhosPholipid Test To one ml of 5% magenta dyestuff aqueous solution is added IOOO picoliters of a 5% aqueous solution of rhncrholiri~l SV. A heavy precipitate forms immediately.
PolY(N-vinYI-4-~,~1lulidulle) Test:
In the same manner an aqueous solution of poly(N-vinyl-4-pyrrolidone) is added to the aqueous solution of dyestuff. No incnll~hili7sltinn reaction occurs.
Test B shows the rapid formation of a water-insoluble coacervate when a polymeric quaternary ~mmnni.lm salt ( Floc-Aid 19), an amino compoumd (poly-4-villyll,~lidill~), or a rhncrhnliri~l compound is mixed with the water-soluble, anionic magenta dyestuff solution in excess, showing that these cnmrolln~c are-suitable as mordants in the ink-acceptor materials of the invention. Poly(N-vinyl-4-pyrrolidone), however, forms no insoluble coacerYate with the dyestuff and would not be selected as a mordant component of the materials of the invention.
The ink-acceptor materials of the invention, in addition to the l~ d water-absorbing polymer and water-soluble mordant, contain certain surface-modifying polymeric particles which, in cnmhin~tinn with the ~ ud~".,.l polymer and the water-soluble mordant, provide an ink-accepting rnmrnritinrl having a number of 11y superior properties. These properties include, not only rapid water-absorption and dye retention, but also a desired degree of surface roughness, a low coefficient of friction, and a porous surface that contributes to short drying time. These desirable properties are achieved by ill~,ul~ulaLill~ in the coating ~.. I.~.~.I;nl) that forms the surface of the irlk-accepting ~ J~ , clear, non-porous polymer beads, preferably cllhct~ntiS-lly spherical beads, having diameters in the range from about 3 to 15 ,um, preferably 6 to 13 ~Lm. In addition, the beads have a specific gravity not cl~hct~nti:~lly greater than that of the coating .. l,.. ~,l,.. ,. Especially preferred are ~WO 95116561 2 1 7 8 ~ 4 1 PCTIUS94/14501 beads of poly(methyl lL~tll~dcly' ) and poly(dimethylsiloxane) having specific gravities in the range from about 0.4 to 1.2.
Examples of such beads include the clear transparent, spherical polymer beads of- 9-13 ~bm diameter which are available from Esprit Chemical Company as Soken MR13 S beads. The polymer is a crosslinked poly(methyl Ill~ a.,l~' ) of which the monomers are 97 wt. % methyl lll~LLa~ly~ and 3 v~t. % ethylene glycol dilll~lla~ly~ Another example is the GE SR346 bead product of General Electric Company. This product consists of poly(dimethyl siloxane) spherical beads of 7 to 12 ~m diameter.
In accordance with the invention, the applicants have found that the addition of10 such polymer beads to the surface layer containing a IJlclla~ ,d water-absorbing polymer improves the water-absorption of the acceptor material, reduces or eliminates multifeed jams and other problems in the feeding of sheets of the acceptor material in printing apparatus, and reduces or eliminates the blocking and image offset of stacked sheets. Unexpectedly, the illcull~ul~lLiull of the described organic polymer beads in the 15 surface layer of the materials of the invention does not impair the l ~ l clarity of the ink-accepting material. Thus, the materials of the invention are quick drying, form water-resistant and light stable images, and have excellent lln~ clarity and sheet feeding and handling properties.
Although applicants again do not wish to be bound by theoretical PYrlon~tinnc 20 it appears that the orgamic polymeric particles or beads of low specific gravity and of 3 to 15 ~m diameter are IJlclulllillalllly at or near the surface of the coated layer in which they are ill~.ul~l ' Because of their low specific gravity, they do not settle to the lowest level of the coated layer. Being at or near the top of the layer and being of ~,u~lul particle size, the beads, or a substantial portion thereof, protrude from the 25 surface of the layer. This results in the desired surface roughness. Since the particles are c~h~onti:llly spherical, the surfæe also has a low coefficient of friction. In addition, the beads contribute to excellent water àb~ul~Livi~y by the ink-accepting material. Preferably, also the beads are formed of a polymer such as poly(methylIll~,illa~,ly' ) or poly(dimethyl siloxane) that has a refractive index close to that of the hardened water-absorbing polymer; thus the ~ ""~ clarity of the layer is 511het~nti~11y retained.
The surface roughness of the materials of the invention can be expressed in terms of a BEKK cm~othnPee Ill~,~allLCIII~ . This well-known definition of ~
S is measured by means of a BEKK !~mf~othn~ ee and Porosity Tester ~hich is supplied by Buchel-Vamder Korput Nederland BV of Veenendaal, Holland. The lll~aa~Cl~ are expressed in reciprocal seconds. The BEKK em~othn~eC of the materials of the invention is in the range from about S to 60 sec~~ amd, preferably, is in the range from 10 to 40 sec~l. The static coefficient of friction is less than about 0.45 and preferably 10 less than 0.35. The kinetic coeftlcient of friction is less than about 0.350 amd, preferably, is less than about 0.300. ~oefficients of friction are measured with a TMI
coefficient of friction instrument. These levels of roughness and of coefficient of friction can be achieved by ;,.~ in the coating ~OIIIy~a;~iOI~ for the uppermostor surface layer of the material of the invention ..yyl, ~ 'y 0.5 to 4 weight percent 15 on dry basis of sllhct~ntil~lly spherical polymer beads of 3 to 15 ~m diameter.
Preferably, the c~nl~ntr~tir~n of beads in the uppermost layer of the ink-accepting cnmr..-;tinn is in the rarlge from àbout 1.5 to 4 weight percent based on the amount of water-absorbing polymer in the layer.
In one ,".l.o,i;.,...,l of the invention, the BEKK ~ 11--... of the surface is 38 20 sec ~, as compared with > 1000 sec~~ for an otherwise identical control material containing no polymer beads. For that same rll.llfl.1;....,1 the static amd kinetic ~,ucrrlci~,llL~ of friction are 0.328 and 0.282, Ic ~y~Li~ , for the control, these coefficients are >1.0 and 0.560, I~,.y~,~,~i~.,ly.
The effect of the beads on 1 l . .~ . clarity of the materials of the invention,25 expressed as loss of ~ l density compared with an otherwise identical controlwhich contains no beads, is less than about 0.04 density units. Thus, although the non-porous polymeric particles roughen the surface of the material and convert the normally non-porous, smooth surface of the hardened polymer to a porous condition, they do not cllhet~nti~lly impair the 1,,."~",;~;:.", clarity of the layer.

~WO 95/16561 2 1 7 8 8 4 1 PCT/US94114501 T,, .~.",~..". clarity of the materials of the invention can be measured by laminating ten strips of the film with a coating of glycerine on each surface to match the refractive index of the film at the air interfaces and measuring the ~
density. By this test the control having no beads in its surfæe layer measures 0.04 S ~ , density; the material of the invention is cllh~tsnti~lly as clear, i.e., measuring 0.06. Thus, the addition of the polymer beads to the surface layer does not substantially reduce or impair its ~ clarity. As for drying time, the control requires more than two minutes to dry a large area of black ink (I in.2), while the material of the invention with the same area of black ink requires only 45 seconds.
Surface gloss of the acceptor materials of the invention can be controlled by choice of mordant. Applicants have found that use of the polymeric quaternary :lmnnrmil-nn mordant, Celquat L-200, with hardened gelatin as the water-absorbing material, results in a matte surfæe material having low gloss and excellent tooth for manual pencil or ink pen marking. In contrast, acceptor materials of the invention 15 having high gloss (which is desirable for image quality) are obtained when the mordant is a non-ionic amino compound such as poly(4-v;~ ,y.;dil.~), or a ~
compound such as r~ l;l ;A EFA. Surprisingly, the addition of polymer beads to the surface layer does not cllhct~ntislly reduce the gloss of such glossy materials.
The acceptor material of the invention accepts the ink dots cleanly and allows 20 sufficient ~ I time to achieve good dot ~ ,LI~LiU--, yet permits pPnPtr~til-n of the inks to achieve proper hue and chroma without beading. At the moment of contact, the ink vehicle begins to diffuse into the acceptor layer, increasing the ~ " ofdyestuff in the applied droplets on the acceptor material surface. The ionic colored dyes also begin to diffuse into the material where they are captured and bound 25 irreversibly by the mordant as a coacervate which in the single layer ~.~ ' is distributed uniformly throughout the coated layer. This coacervate formation causes each colored dye dot to be fixed in l~tSi,L.~;u.i with good edge defmition onto the mordant functional sites, and the image quality is thus preserved. Also, the high local ~""~ . . ,1".1;. " ~ of dyestuff results in a high chroma (or color saturation) and efficient ~0 packing density ~f the dye dots.

The aqueous vehicle for the ink dyes is wicked away from the porous, uppermost surface rapidly by the hydrophilic, water-absorbing polymer of the acceptor material. In effect, the coated layer appears to perform a "I~ r separation of the ink cnmro~itirln evidently retaining the dyes on the active mordant surface sites 5 while permitting the liquid vehicle to diffuse readily to the unswelled portion of the polymer. This c...,.l.;"~;..,. of actions results in high chroma, good light stability, water fastness, and short drying times. For all but a very large black image area, the inks are dry to the touch as the print emerges from a thermal ink jet printer such as the "500 or 550 C Desk Jet" printer of the Hewlett-Packard Company and the BJC600 Color 10 Bubble Jet printer of Canon Company. Large black areas (50% page coverage) become dry within 45 seconds.
The acceptor materials of the invention are capable of absorbing and wicking away rapidly all the aqueous vehicle of the inks and dispersing the liquid throughout the water-absorbing polymer, leaving the surface of the acceptor material dry to the 15 touch. The water-absorbing polymer swells by up to 400% in so doing, but thenremains water-insoluble at room t~ a~ because of the high degree of hardening pre-treatment.
Figure 2 shows another ....I,i~ ~; ,....1 20 of the invention wherein support 12 is coated on both sides with ink accepting ...",l,r.~ 14 and 15, which can be the same 20 or different and which can be coated to the same or different 11.~ The ~",1,~,1;",. .,l~ of Figures I and 2 can further include one or more protective overcoats in which the polymer beads are dispersed (not shown) on top of ink-accepting ...llC 14 and 1,.
Figure 3 shows still another ~ ,o~ . ." 30 of the invention wherein an image-25 forming layer 32 containing the mordant compoumd and a portion of the water-absorbing polymer is coated on support 12. Coated over layer 32 is transparent water-absorbing polymer layer 34 which is substantially free of said mordant, but contains non-porous polymeric beads (not shown) that roughen the surface of the water-absorbing polymer layer and render it semi-porous. The hardened, transparent polymer 30 of the water-absorbing wicking layer 34 has no affinity for the ionic dyestuffs of the ~Wo 95/16561 2 1 7 8 8 4 1 PCT/US94/14501 ink jet inks, which are captured completely and irreversibly by the mordant material in layer 32. This .,lllVOdilll~.l.i is suitable for outdoor display and for other uses when a high degree of protection for the image-forming layer is desired, since the image layer is well below the upper surface of the film. If desired, the ,lllbvd;lll~lL of Figure 3 can 5 be further protected by a transparent polymeric overcoat 36, in which case the polymeric beads are dispersed in the overcoat 36.
Figure 4 shows still another, ~ ' 40 of the invention wherein an image-forming, mordar~t layer 44 is coated over the water-absorbing polymer of wickinglayer 42. As in .. ,.l,o.l:.. ,l 30, a protective overcoat 46 may or may not be present.
10 F~ . ..l 40 can be useful when the maximum possible image definition is desired, since the dyestuffs are captured near the upper surface of the acceptor material before substantial diffusion of the imaging dots can occur.
An important aspect of the invention is the chemical hardening of the matrix-forming polymer in the making kettle prior to coating. In this way, a higher level of 15 control of hardening is obtained than could be achieved by addition of hardening agent to the coating machine delivery line as is UUIl~ .iUll~l in, for example, the l..^....rn. l.~ c of ~ uy~ l products using gelatin. F~lllll.,l~llulc, no post-hardening or incubation of the coated acceptor material is required.
Kettle l~lc~ll~.l~,ll;l.~ is A~.. l.l;~l.. ;I by adding the hardening agent to the 20 polymer solution at elevated r~ II G, e.g., 49C. (120F.), and then l~
that solution t~ la~ulc umtil all the agent is consumed in cross-linking of the polymer. The reætion is ~ by a . ~ rapid increase in viscosity to a ~lhst~lltiAlly higher but coatable viscosity. The reaction is deemed at ~-qllilihrillrn and therefore complete when no further viscosity increase is seen after holding the 25 c-- .~ o.~ at the indicated elevated t llllJ~ lllC for 15 hours.
The particular hardening agent to be used can vary according to the ~..l.ll.c~
of the polymer to be hardened. For gelatin, a preferred hardener is dimethyl hydantoin.
Various aldehydes, e.g., rvlll. l;lc~yJc~ g' ' ' ' .~lc and ~ h~uu are also useful. Other useful gelatin hardeners are disclosed, m "The Theory of the 30 Pl...l..~ .ll: Process," MæMillan Publishing Co., Inc., New York, Fourth Edition, T.

WO 95/16561 2 t 7 8 8 4 1 PCTIIJS9~114501 H. James, Editor; (see Chapter Ill, pages 77-87, by Burness and Pouradier, entitled "The Hardening of Gelatin and Emulsions"), the disclosure of which is ill~UIIll ' 4 herein by reference. For 100 percent hydrolyzed poly(vinyl alcohol), preferred hardeners are boric acid and urea-formaldehyde resins. Hardening agents for other 5 polymers include, for exarnple, the l,;r", 1;~ aziridine, trimethylolpropane tris(~-aziridinyl) propionate, known as XAMA-7, which is available from Sanncor Co. Theamount of hardening agent in the ~ " of the invention can vary over a f range. In general, however, the amount should be sufficient to render the polymer insoluble in water at ~ lLulc:. below 50C while retaining water solubility 10 at L~ /.ldLUl~a above about 50C, so that the ink-accepting ~...,.I.n~,l;.." of the invention can be coated on a support from an aqueous medium. In general, the desired amount of hardening agent can be determined by the f fl lilihril-m viscosity achieved by adding the agent. Sufficient hardening agent is added to increase the viscosity of the aqueous polymer coating ...,..1.~.l;..,. from about 10 to 200% at a given solids15 ~ . f ~;"" but not so much as to render it uncoatable. Preferred weight ratios of hardening agent to gelatin are in the range from about 1:1 to 1:10, although other ratios are also suitable. Other hardenable polymers can be hardened with similar ratios of hardening agent.
To prepare the irlk-accepting ,.. 1.. ~;l;.. , of the invention for coating as a single 20 layer on a support, preferably the hardenable water-absorbing polymer, the hardening agent, the water soluble mordant, the polymer beads, and water are mixed together in a vessel with stirring and moderate heating. If desired, the polymer and hardener can be mixed before adding the mordant and beads, but it can be ddvallL~,~vu~ to add the mordant before the polymer is hardened. This can have the effect of grafting the25 soluble mordant compound to the wicking polymer. Other desirable ~ of the coating f--mro~ifi-~n such as a coating aid can be added before or after hardening the matrix polymer.
Conventional coating techniques can be used for producing the coated ink acceptor materials of the invention, including, for example, spray coating, bar coating, 30 extrusion die coating, air knife, knife over roll coating, reverse roll, curtain coating, ~'O YS/16561 2 1 7 8 8 4 ~ PCT~Sg4/1450l blade coating, and gravure coating of a continuous web of the support material. The coated web is dried in ~ u~ ll;ulldl manner, e.g., by contact with warm air while passing through a drying chamber. The total thickness of the dried ink-acceptingcomposition on the support, whether coated as one or a plurality of layers, is preferably in the range from about I to 25 ,um, (although greater Ll~;cLl~c~ can be used) and, most preferably, is in the range from about 2 to 18 ILm. The dried coated web can be wound on a take-up roll and later cut to desired sheet siæs.
The coated amount of water-absorbing polymer must be sufficient to absorb the substantial volume of water that is present in the ink jet droplets. In general, an amount of water-absorbing polymer of at least about 2.0 grams per square meter on the support will adequately absorb the water in the ink jet droplets and will provide a quick-drying material. Likewise, the ink accepting . v,.,~ , must contain a sufficient amount of mordant to bind all of the dyestuff in the ink. In general, the amount of mordant should be at least about O.S weight percent and, preferably, at least IS S weight percent of the amount of dry water-absorbing polymer in the ink accepting . ~""l,n~,l;.". The maximum mordant content should not be so high as to impair the desired physical properties of the acceptor material. Preferably, the mordant r~n~ ntr~tion does not exceed about 30 weight percent based on the weight of the~vater-absorbing polymer.
The examples which follow illustrate certain specific ~ ù~ of the invention and describe ,ulllucu~lLive tests with commercially available ink jet acceptor materials.
EYample I - l~ardened Gelatin and Polymeric 1~ .r A Mordant.
A batch of solution was prepared for coating in accordance with the invention.
A vessel fitted with a mixer and a heater was charged with 93 grams of 10%
suspension of gelatin in water (available as T7188 from K-~K Corp.) and S0 grams of distilled water. The mixture was stirred and the t.,~ lu.c was raised to 49C
(120F). After S minutes of stirring, the viscosity was 23 mPa s. Then 1.72 grams of a 55% aqueous solution of dimethyl hydantoin (Damtoin hardener, av~ilable from Lonza wo 9~/16561 2 l 7 8 8 4 1 PCr/US9411450 Co ) was added with continued stirring. After 10 minutes, the viscosity had increased to 35 mPa s, and no further increase was seen. Then was added as the mordant, 2.30 grams of aqueous solution of a polymeric quaternary ammonium compound (FlocAid 19 from National Starch and Chemical Co.) with stirring, followed by 0.23 grams of 5 cross-linked poly(methylmethacrylate) beads, 9-13 ~m in diameter (Soken MR-13Gbeads available from Esprit Chemical Co ) and 2.79 grams of 2% aqueous solution of u~Lyllul~ u~yuolyethoxy-ethanol (Triton X-100 available from Union Carbide) as coating aid. The ~ l,U~ .~Lul~ was reduced to 38C (100F), and the resulting thickened solution was ready for coating.
The thickened solution was coated on transparent 98 ~m thick (3.85-mil) poly(ethylene L~ ' ' ) film and dried to provide a dry coverage of 9 ~ UalC
meter of support, resulting in a dried ink-æcepting layer having a thickness of 9 ~m.
When this film was imaged on a Hewlett-Packard 500C DeskJet ink jet printer using a cartridge of Hewlett-Packard ink containing ionic dyes, the individual ink images 15 emerged drv from the printer. Dot resolution was excellent.
To test water resistance of the printed dyes, a strip of the printed film was immersed in water for two minutes, then removed and dried. Reflection dye densities of immersed and non-immersed strips were measured with an X-Rite Ref~ection D~ ",- " Model 408. The results of these ~ are listed in Table I and 20 .1~ . . " .. ,~ the water-fastness of the ink acceptor film of Example 1:

~WO 95/16561 2 1 7 8 8 4 1 PCTNS94/14501 TABLE I
Water-Fastness Test of E~ample 1 Film S
Density Difference Between Non-Optical Density Optical Density Immersed and Dye Before T After ~ Immersed Films 10 Cyan 1.42 1.54 +.12 Magenta 0.96 1.00 +.04 Yellow 0.86 0.89 +.03 Black 1.60 1.66 +.06 Tne results recorded in Table I show that immersion of the imaged film of the invention in water caused no density loss, thus indicating that essentially none of the mordanted dye was washed from the film. The increases in density shown for certain of the dyes are believed to have resulted from swelling and possible dye l~- .~ lL,..,....
amd repacking. In f,..~ , a ..~ ll~.,;al ink jet acceptor film when printed and 25 subjected to the same water-immersion test showed a magenta dye density change of -0.77.
LiPht ExPosure Testin~ of ExamPle I Film of the Invention and a Commercial Film .
Example 1 film of the invention and a ~,w~ .,;dlly available ink jet recording 30 film that were identically imaged in am ink jet printer were exposed to GE F400W
fluorescent bulbs at 5,000 lux intensity for 72 hours, at the end of which time they were compared to otherwise identical unexposed strips (ASTM F767-82) of the same- imaged films. The reflection densities (indicating dye light stability) are shown in Table II for the Example 1 film and for the commercial film.

Cl~ . of Light Exposure Results of Example 1 Film of the Invention and C~. .h.l Film Density of Density of Density Difference Density Difference Non- Exposed Between Non- Belween Non-Exposed Film Exposed and Exposed and Film of of Exposed Film of Exposed 10Dye Example I Example 1 Example 1 ('~ .; I Film Cyan 1.42 1.27 -0.15 -0.89 Magenta 0.96 0.94 -0.02 -0.02 15Yellow 0.86 0.80 -0.06 -0.17 Black 1.60 1.50 -0.10 -0.38 Example 2 - Hardened Gelatin and Polymeric ~u ~ A Mordant.
In this example the mordant was the polymeric quaternary - ,..".,.,; ~ ..
compound Celquat H100. The mordant and wicking polymer, namely, ~Jl;,llald~
gelatin, were included in the same layer. The coating rnnnr- cition was prepared as in Example I from the ~.. l.. ~ as follows:
20.0 grams 10% gelatin 0.37 grams 55% Dantoin hardening agent

6.0 grams 2.5% Celquat H100 mordant 0.06 grams 2% Triton TX-I00 coating aid 0.05 grams Soken MR-13G poly(metbyl ~ ,;ll~ly' ) beads (9-13 ~m) 73.52 grams Water The solution was coated on a transparent polyester film support at a ~,~.... ,.l".l,"" of 9 ~I~UII:IS~lUa.lC meter and dried. After printing with colored aqueous inks in an ink jet thermal printer the resulting image was tested and compared with a CUIIUII~,IC;~ll film for water-immersion stability arld light stability of the dyes as previously described. After water immersion for two minutes the Exa~nple 2 film of ~VO 95/16561 2 1 7 8 8 4 1 PCT/IJS94/14501 the invention had a nlagenla dye density loss of only -0.03, while the .,~JIIUII.II,;al film decreased in ma~enta density by 0.77 units. The results of the light exposure test are listed in Table Ill.
TABLE III
Comparison of Light Exposure Results of Example2 Film of the Invention and C~ .; I Film Film of Film of Densit~ Difference Density Difference Dye Example 2 Example 2 Between Unexposed Between Unexposed Before After and Exposed Film and Exposed Exposure Exposure of Example 2 Cl .;.. 1 Film Cyan 1.36 1.08 -0.28 -0.59 Magenta 0.94 0.90 -0.04 -0.06 Yellow 0.53 0.51 -0.02 -0.11 Black 1.59 1.46 -0.13 -0.20 As in the other cwll~al~ivc tests, Table III shows superior dye fastness after light exposure for the film of the invention containing the polymeric cationic mordant, especially with regard to cyan dye stability.
20 E~ample 3 - Hardened Gelatin and Barium lon Mordant.
As in Example 1, a heated mixing vessel was charged with 20 g. of a 10%
aqueous suspension of gelatin and the t.l~ la~ul~ was raised to 49C (120F.). To the gelatin suspension was then added 0.38 g of a 55% aqueous solution of dimethyl hydantoin (Dantoin hardener). The mixture was stirred for 5 minutes to increase its 25 viscosity; then was added 0.6 g of a 2% aqueous Triton X-100 coating aid, 0.05 g of 9-13 ~m cross-linked poly(methyl Ill~,~La~,ly;a~.) beads (Soken MR 13G beads) amd 2.0 g of 10% aqueous solution of barium chloride. The resulting ink-acceptor ~
was coated on pol~(ethylene h~lC~ llUL~'C) film and dried to yield a.dried coating of 2 L~ Udl~; meter. The material was then printed with a magenta ink jet aqueous 30 ink and was subjected to the water imrnersion test as previously described. A control WO 95/16561 2 l 7 8 8 41 PCT/US9-S/14501 ~

film material containing no barium chloride was printed and tested in the same manner.
The control showed a magenta dye density change of -0.27. The acceptor material of the invention, containing barium ion as mordant, showed a magenta dye density change of only -0.06, thus ~ g the superior water resistance of a dye printed on the 5 novel ink acceptor material of the invention.
E~ample 4 - Acceptor Material Containing Poly(4-~ ~lp~ ) Mordant.
A vessel fitted with a mixer and a heater was charged with 48.8 grams of 7.5%
suspension of gelatin in water (available as T7188 from K&K Corp.) and 36.6 grams of 10 distilled water. The mixture was stirred and the ~ laLul~; was raised to 49C(120=F). After 5 minutes of stirring, the viscosity was 23 mPa s. Then 4.88 grams of a 55% aqueous solution of dimethyl hydantoin (Dantoin hardener, available from Lonza Co.) was added with continued stirring. After 10 minutes, the viscosity had increased to 35 mPa-s, and no further increase was seen. 8.0 grams of 10% poly(4-15 viu,~l,uy,;.li"e) aqueous solution (available from Monomer-Polymer Corp.), pH adjusted to 4.0 with acetic acid, was added with stirring, followed by 0.122 grams of particulate Malogel starch (available from National Starch and Chemical Co.) as a lUU~ .lg agent and 1.7 grams of 2% aqueous soluvion of o.,lyl~ll..lu,~yluol.~.l.v,.y-ethanol (Triton X-100 available from Union Carbide) as coating aid. The batch was adjusted to pH 8.0 20 by addition of NH40H, the t~lll,U~ UlC was reduced to 38C (100F), and the resulting thickened solution was ready for coating.
The thickened solution was coated on transparent 3.85-mil poly(ethylene t~ ' ) film (Melanex 6093, available from ICI Ltd.) at a dry coverage of 3 ~lla~aulu~ meter of support, resulting in a glossy, dried ink accepting layer 3 ~Im 25 thick. When this film was imaged on a Hewlett-Packard 500C DesWet ink jet printer with a cartridge of Hewlevt-Packard ink containing ionic dyes, the individual ink images emerged dry from the printer. A large area black image did not transfer ink to a cotton ball after 45 seconds of drying time. Dot resolution was excellent.
A strip of the imaged film was immersed in water for two minutes, then 30 removed and dried. Reflection dye densities of immersed and non-immersed strips .

~wo 95116561 2 1 7 8 ~ 4 1 PCTIUSg4/1450 were measured with an X-Rite D~ ...,. , Model 408. The results of these 111~,~1~111~111.~11~ are listed in Table IV and .'- - the water-fastness of the ink acceptor film of Example 1:
TABLE lV
Water-Fastness Test of Example 4 Film Density Difference Between Non-10 Optical Density Optical Density Immersed and Dye Before I After T Immersed Films Cyan 1.50 1.52 +0.02 Magenta 0.87 0.87 0.00 Yellow 0.80 0.91 +0.11 Black 1.70 1.71 +0.01 The results recorded in Table IV show that immersion of the imaged film of the invention in water caused no density loss, thus indicating that essentially none of the mordanted dye was washed from the film. The increases in density shown for certain 25 of the dyes are believed to have resulted from swelling and dye .~- ., .~,..,....1 and packing. In ~ . a C~ ;CII ink jet acceptor film when printed and subjected to the same water-immersion test showed a magenta dye density loss of -0.77.
Although in Example 4 the pH of the batch was adjusted to 8.0 by adding NHIOH, this adjustment was not required. The aqueous coating, ,..,l.c.~ , can be at 30 arl alkaline or acidic pH as .11 .,.. ~l-, .~.. 1 heremafter. The adjustment to an alkaline pH
simply .1---- that the poly(4-v;~ ) need not be protonated to its quaternary ,...", ,......, form in order to function as a mordant for anionic dyestuffs.

wo 951165C1 2 1 7 8 8 4 1 PCT/Us94/l450 I.iQht Exoosure TestinQ of ExamnIe 4 Film of the Invention and a Commercial Film The non-immersed Example 4 film of the invention and a uu~ lly available ink jet recording film which were identically imaged in an ink jet printer were exposed to GE F400W fluorescent bulbs at 5,000 lux intensity for 72 hours, at the end 5 of which time they were compared to otherwise identical unexposed strips (ASTMF767-82) of the sarne imaged films. The reflection densities (indicating dye retention) are shown in Table V for the Example 4 film and in Table VI for the commercial film.
TABLE V
Film of the Invention -- Optical Density Before and After Light Exposure Density Difference Film of Example 4 Film of Example 4 Between Unexposed Dye Before EYposure After Exposure and Exposed Film Cyan 1.50 1.35 -.15 Magenta 0.87 0.81 -.06 20Yellow 0.80 0.78 -.02 Black 1.70 1.56 -.14 TABLE Vl C~ .;.. 1 Film -- Optical Density Before and After Light Exposure 30 C~. .;.d C~ .;.. 1 Density Difference Film Before Filrn After Between Une~posed DyeEYposure Exposure and Exposed Film Cyam 1.50 0.91 -0.59 Magenta 0.99 0.93 -0.06 Yellow 0.88 0.77 . -0.11 Black 1.57 1.37 -0.20 ~WO 95116S61 2 1 7 8 8 4 1 PCT/US94/14501 ~ omr:lriqnn of the density differences in Tables V and VI shows that the light stability of the imaged film of the invention was substantially improved over that of the ~,VIIIIII~ film, especially with regard to cyan dye stability.
Fig. 5 of the drawings also illustrates the superior light stability of the S Example 4 film of the invention as compared with the ~UIIIII~ ;GI film. The cyan dye densities of the two films are plotted in this figure over extended periods of time for high intensity light exposure and for normal room light exposure. Curve A of Fig. 5 shows that the cyan dye density of the film of the invention remained s~lhrf~nti~ y constant over a period of 110 hours of normal room light exposure. In contrast, 10 Curve B shows that the cyan dye density of the ~,vl~ l film decreased linearly from 1.5 to about 1.1 after 110 hours. Curve C plots the cyan density for the film of the invention after exposure and Curve D plots the cyarl density for the commercial film after the same exposure. As Curves C and D illustrate, the Cvllllll~ film decreased much more sharply in cyan density than did the film of the invention.
Example 5 - Acceptor Material Containing Triamine Mordant.
In the same manner as in Example 4, a coating ~ .v~:l;.,., having the following rnmrnr;~inn was prepared:
20.00 g 10% gelatin 0.30 g 55% Darltoin hardener 2.50 g 10% high molecular weight amine (Jeffamine T-403) 0.05 g 20% Triton X-100 coating aid 0.04 g dimethylsiloxane particles (GE SR 346) 77.11 g water This aqueous ~.,I.v :ll" was coated at c,l",ll ly 9.8 ~,I.IIII:J~ Ual~ meter (2.0 Ib/1000 ft2) solids on a poly(ethylene terephthalate) film support and dried; the dried layer had a thickness of about 9 ,um. The resulting ink acceptor material of the invention was printed with colored ink in a thermal ink jet printer and produced image densities as follows: cyan, 1.72; magenta, 1.48; yellow, 1.15; and black, 1.94. A strip 30 of the printed film was subjected to the 2 minute water immersion test. Magenta density before the water test was 1.48 and after the test was 1.42. The density change of only - 0.06 indicates excellent water resistance and marked superiority over the cU~ ,,;al film referred to in Example 4, which suffered a magenta density change of -0.77 in the water-imme-rsion test.
S Example 6 - Acceptor Material Containing Another Triamine Mordant.
An ink acceptor material of the invention was prepared and tested as in Example 5. The cnmrocition differed only in that the mordant compound was the high molecular ~eight triamine, Jeffamine T-S000. Densities of dyes in a printed saml~le of the film were: cyan, 1.74; magenta, 1.54; yellow, 1.21; and black 2.56. A sample10 subjected to the water dip test hâd a magenta density of 1.59 before immersion and 1.65 after immersion; The density difference of +0.06 shows that essentially no dye was lost during water immersion.
Example 7 - Acceptor Material t~ O Poly(4-~ ' -) Mordant and 15 Polymer Beads.
Using the procedure of Example 4, a coating ~ of the following "",l,.",. .,l~ was prepared:
20.0 g 10% gelatin 0.37 g 55% Dantoin hardening agent 200~ g 10% poly(4-vinyl pyridine) mordant 0.60 g 2~o Triton TX-I00 coating aid 0.05 g Soken MR-13G poly(lll~,Lll~yll-l~lll~,~,ly' ) beads, 9-13 ~m diameter 78.73g Water 25 This cnmro~iti--n of the invention was coated on polyester film support and subjected to high intensity fluorescent light exposure as in Example 4. Table VII provides a of the dye densities of the film of the invention and of a ~,ullllll~.~;.d ink jet acceptor film after ~"",p .~I,i,~ exposure.

~vo 95/16561 2 1 7 8 8 4 1 PCT/IJSg4/14501 TABLE VII
Light Fade C~ of Example 7 Film and 1'~ .;.. 1 Film - 5 Film of Film of Density Difference Density Difference Dye Example 7 Example 7 Between Unexposed Between Unexposed Before After and Exposed Film and Exposed E~posure Exposure of Example 7 C~ .;,.1 Film Cyan 1.46 1.31 -0.15 -0.59 Magenta 0.92 0.86 -0.06 -0.06 Yellow 0.83 0.75 -0.08 -0.11 Black 131 1.22 -0.09 -0.20 The results recorded in Table Vll show markedly less density loss for cyan and ~,~"~ ly less density loss for yellow and black in the film of the invention than for 15 the ~,UI~IIII.,.I~;~I film after high intensity light exposure.
The Example 7 film of the invention and the commercial film were also subjected to the 2-minute water immersion test as previously described. The magenta density loss for the commercial film was 0.77, but only 0.02 for the film of theinvention. Thus, even with the lower mordant content, the film of the invention 20 provided superior light stability and water resistance.
Example 8 - Acceptor Material Containing Mordant and Water-Absorbing Polymer in Separate Layers In this example the mordant was poly(~vi~ ,yl;dillG) and the water absorbing 25 material was hardened gelatin. To prepare the ink acceptor material of the invention the following solutions were formed in the manner described in Example 4:

WO 95/16561 2 1 7 8 ~ 4 1 PCTIUS9~14501 Solution A
40.0 grams 10% gelatin 40.0 grams 10% pOIy(4-Vill,~ l;d;.lc) solution 0.4 gram 55% Dantoin hardening agent 0.1 gram 2% Triton TX-I00 coating aid 19.5 grams Water Solution B
98.77 grams 10% gelatin 0.99 grams 55% Dantoin hardening agent 0.15 grams poly(dimethyl siloxame) particles, 7-12 ~Lm diameter (GE SR346 from General Electric) Solution A was coated as a base coat at a solids nnnrl~ntr~tinn of 2.4 ~,IUII15/S~IU~C
15 meter (0.5 lb/1000 f2) on a polyester film support. After drying the base coat, solution B was coated over it at a solids ~...,...,1.,.1;..,. of 4.9 L~ /a~ alc meter (1.0 Ib/1000 ft2) to form the top coat.
Tbe resulting two-layer film was imaged with ink jet colored ink in a thermal ink jet printer and the resulting image was compared v~ith the c~ ,;l film for light 20 stability and water-immersion stability as previously described. For the film of tbe invention, water stability was superior to that of the Cvlllll~ film as in the other examples. Results of the light stability tests, in terms of reflection densities of the mdividual dyes, are listed in Table VIII below.

~Wo 95/16561 2 1 7 8 8 4 1 PCr/US94rl4501 TABLE~
Light Stabilit~ of the Two-Layer Film in Ct . ;~Uli ~ ith Commercial Film Film ûf Film of Densit~ Difference Density Difference Dye Example 8 Example 8 Bet~een Unexposed Betwe n Unexpûsed Before After and Exposed Film and Expûsed Expûsure Exposure of Example 8 (~ h~l Film Cyan 1.87 1.67 -0.20 -0.59 Magenta 1.15 1.15 0 -0.06 10Yellow 1.08 0.98 -0.10 -0.11 Black 1.48 1.33 -0.15 -0.20 Example 9 - Acceptor Material Containing Pt . '-~ ' Mordant and Pob(methyl '' .~lali) Beads.
A solution was prepared for coating in accordance with the invention A vessel fitted with a mixer and a heater was charged with 93 grams of 10% suspension of gelatin T7188 from (K&K Corp.), in water and 40 grams of distilled water. The mixture was stirred and the t~ UIc was raised to 49C (120F). After S minutes of stirring, the viscosity was 23 mPa s. Then 1.72 grams of a 55% aqueous solution of dimethyl hydantoin (Dantoin hardener, available from Lonza Co.) was added with continued stirring. After 10 minutes, t~le viscosity had increased to 35 mPas, and no further increase was seen. Then waS added 3.0 grams of 30% aqueous solution of rh~Crh~.liri-l EFA (Mona Industries, Inc.) with stirring, followed by 0.23 gram of cross-linked poly(methyl lllcLila~,l.ylaLc) beads (Soken MR-13G, 9-13 ~m diameter, available from Esprit Chemical Co.) and 2.79 grams of aqueous solution of o~,~yl,ul.~ y~!olyethoxy-ethanol (Triton X-100 available from Union Carbide) as coating aid. The ~ u~laL~ was reduced to 38C (100F), and the resulting thickened solution was ready for coating.
The thickened solution was coated on transparent 3.85-mil poly(ethylene ~clc~ L'~ ) film (ICI 6138) at a dry coverage of 9 ~ /a~ meter of support, WO 95/16561 2 1 7 8 ~ 4 1 PCT/US94114501 resulting in a glossy, dried ink-accepting layer 9 ILm thick. When this film was imaged on a Hewlett-Packard 500C DeskJet ink jet printer using a cartridge of Hewlett-Packard ink containing ionic dyes, the individual ink images emerged dry from the printer. Dot resolution was excellent.
A strip of the imaged film was immersed in water for two minutes, then removed and dried. Reflection magenta dye densities of imrnersed and non-immersed strips were measured with an X-Rite D~ il.. , Model 408 and compared with those of a similarly printed and water-immersed l,Ullllll~,lV;al ink jet acceptor film. The magenta density change after water immersion for the film of the invention which10 contained the ~ i mordant was only -0.03 but was -0.77 for the ~vllll~ ;
film. This shows that essentially none of the dye was washed from the acceptor material of the invention and ~l..,..."~ its superior water resistance in CUIIIIUCUi:~VII
with the uvlillll.,l.;dl film.
15 Lioht ExPosure Testin of Example 9 Film of the Invention and a Commercial Film The non-immersed Example 9 film of the invention and a vulllll~ ,;dlly available ink jet recording film which were identically printed in an ink jet printer were exposed to GE F400W fluorescent bulbs at 5,00û lux intensity for 72 hours, at the end of which time they were compared to otherwise identical umexposed strips (AST~I
20 F767-82) of the same imaged films. The reflection density differences (indicating dye retention) are shown in Table IX for the Example 9 film and for the Cul~ ,;dl film.

~WO 95/16561 2 1 7 8 8 4 1 PCT/US94/14501 _ TABLE IX
C~ . of Light Exposure Results of Example 9 Film of the Invention and Commercial Film S ._ Density of Density of Density Difference Density Difference Dye Non- Exposed Betveen Non- Betwe~n Non-Exposed Film of Exposed and Exposed and Film of Example 9 Exposed Film of Exposed Example 9 Example 9 C~ .;.. 1 Film Cyan 1.42 1.30 -0.12 -0.59 Magenta 0.82 0.80 -0.02 -0.06 Yellow 0.76 0.73 -0.03 -0.11 Black 1.28 1.20 -0.08 -0.20 The optical density data in Table IX show al~;lfirl~ lly better dye light stability 15 for the film of the invention, especially for the cyan dye.
Example 10 - Acceptor Material 1~ J Mordant and Poly(~ ) Beads In this example the ink acceptor material was prepared c--hct ~l~t~ ly as in Example 9, except that a different water-soluble ~ .l;l,;fi was used ac the mordant compound and the ~ of the coating f...... llf~ ;.. were as followc 20.00 g 10% gelatin 0.37 g 55% Dantoin hardener 25 1.00 g 15.67% pl.~.~l,l.. i;l.. i PTC
0.60 g 2% Triton X-100 coating aid 0.05 g GE SR 346 poly(dimethyl siloxane) beads, 7 to 12 ~Lm diameter (available from General Electric Company) 77.98 g Water 30 After coating on polyester f~lm and drying, the coated film was printed with colored ink jet aqueous ink in a thermal ink jet printer. Dye densities measured for a sample of the WO 95/16561 2 1 7 8 ~ 4 1 PCTIUS94114501 film were: cyan, 1.44; yellow, 0.85; magenta, 0.97; and black, 1.88. A sample of the printed film had a magenta dye density before water immersion of 0.94. After the 2-minute water dip test, its magenta density measured 1.04. The density change of +0.07 indicates essentially no dye loss and excellent water resistance.
S The invention has been described in detail with particular reference to preferred )O.l~ thereof, but it will be understood tnat variations and m~rlifir~inn~ can be effected within the spirit and scope of the invention.

Claims (10)

CLAIMS:

1. An acceptor material for inks that contain an ionic dye and an aqueous vehicle which comprises a support and an ink-accepting composition coated on thesupport, characterized in that said ink-accepting composition comprises (a) a water-soluble mordant which, when admixed in excess with said ionic dye in aqueous solution at room temperature, forms a water-insoluble precipitate and a clear, substantially colorless supernatant liquid, (b) a water-absorbing solid polymer, wherein said polymer has been rendered insoluble in water at room temperature by chemical hardening of said polymer at elevated temperature in an aqueous coating solution prior to coating of said coating solution, and wherein said polymer is non-reactive with and permeable by said ionic dye, and (c) non-porous, clear, substantially spherical, polymer beads dispersed in said water-absorbing polymer in an uppermost layer of said ink-accepting composition.

2. An acceptor material of Claim 1 wherein said water-absorbing polymer is gelatin which has been pre-hardened by chemical reaction with a hardening agent prior to coating.

3. An acceptor material of Claim 1 wherein said mordant comprises a polymeric quaternary ammonium compound or a divalent Group II metal ion.

4. An acceptor material of Claim 1 wherein said mordant comprises poly(4-vinylpyridine) or an amino compound characterized by the formula:

wherein A is the hydrocarbon residue of an aliphatic triol having up to about 12 carbon atoms, x, y and z are each positive integers and x+y+z = 3 to about 85.

5. An acceptor material of Claim 1 wherein said mordant comprises lecithin or a phospholipid compound characterized by the formula:
wherein x and y are each 1 or 2, x + y = 3 and R is a C14 - C22 saturated or aliphatic carboxylic acid amidoalkyl radical, said alkyl having from 2 to 6 carbon atoms.

6. An acceptor material for inks that contain an ionic dye and an aqueous vehicle which comprises a support and an ink-accepting composition coated on thesupport, characterized in that said ink-accepting composition comprises (a) a water-soluble high molecular weight amino mordant which, when admixed in excess with said ionic dye in aqueous solution at room temperature, forms a water-insoluble precipitate and a clear supernatant liquid, and (b) a water-absorbing polymer which is non-reactive with and permeable by said ionic dye.

7. An acceptor material of Claim 6 wherein said mordant comprises poly(4-vinylpyridine) or an amino compound characterized by the formula:
wherein A is the hydrocarbon residue of an aliphatic triol having up to about 12 carbon atoms, x, y and z are each positive integers and x+y+z = 3 to about 85.

8. An acceptor material for inks that contain an ionic dye and an aqueous vehicle which comprises a support and am ink-accepting composition coated on thesupport, characterized in that said ink-accepting composition comprises (a) a water-soluble phospholipid mordant which, when admixed in excess with said ionic dye in aqueous solution at room temperature forms a water-insoluble precipitate and a clear supernatant liquid, and (b) a water-absorbing polymer which is non-reactive with and permeable by said ionic dye.

9. An acceptor material of Claim 8 wherein said mordant comprises lecithin or a phospholipid compound characterized by the formula:
wherein x and y are each 1 or 2, x + y = 3 and R is a C14 - C22 saturated or unsaturated aliphatic carboxylic acid amidoalkyl radical, said alkyl having from 2 to 6 carbon atoms.

10. An acceptor material of Claim 9 wherein R is linoleamidopropyl, stearamidopropyl, or coacamidopropyl.