EP1375174B1

EP1375174B1 - Process for the production of a photopaper coating composition

Info

Publication number: EP1375174B1
Application number: EP20030013741
Authority: EP
Inventors: Brian T. Mcaneney; Stephan V. Drappel; Gordon Sisler; Edward G. Zwartz; Guiqin Song; Sandra J. Gardner; Michael S. Hawkins
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 2002-06-19
Filing date: 2003-06-17
Publication date: 2008-05-28
Anticipated expiration: 2023-06-17
Also published as: CA2390901C; CA2390901A1; EP1375174A1; JP2004021263A; DE60321272D1; JP4223332B2

Description

The present invention is directed to papers, and more specifically, to papers for electrography. More specifically, the present invention is directed to coating compositions for application to supporting substrates as a coating, such for use in xerographic engines employing oil-less fusers as well as methods for providing such coating compositions to a substrate.
Certain polyester coated papers are known, reference for example U.S. Pat. Nos. 5,627,128 ; 5,534,479 and 4,692,636 .
There is disclosed in U.S. Pat. No. 4,663,216 a synthetic paper comprised of: (1) a multilayer support, (2) a layer of a transparent film of a thermophotographic resin free from an inorganic fine powder formed on one surface of the support (1), and (3) a primer layer of a specific material. The support (1) comprises (1a) a base layer of a biaxially stretched film of a thermophotographic resin, a surface and a back layer (1b), and (1c) composed of a monoaxially stretched film of a thermophotographic resin containing 8 to 65 percent by weight of an inorganic fine powder.
In U.S. Pat. No. 4,868,581 there is disclosed an opaque paper-based receiving material for ink jet printing which comprises a poly(olefin)coated paper overcoated with an ink-receiving layer which contains a mixture of gelatin and starch. Reportedly, these receiving materials exhibit gloss, good color density and are smudge resistant. Although such receiving materials, when pictorially imaged with an ink jet printing device, may enable images acceptable in appearance and feel, the images thereon are still not believed to be of the same high quality that is customarily expected from and exhibited by photographic prints.
U.S. Pat. No. 6,177,222 and U.S. Patent 6,326,085 disclose a process for forming an image on a substrate, and developing the image with toner. Also disclosed is a coated substrate in which a coating of a polyester which is a poly(propoxylated bisphenol A fumarate) resin, a polyester resin of a terephthalic acid, bisphenol-A-ethylene oxide adduct, cyclohexane dimethanol or a low, from 1,000 to 50,000 molecular weight branched copolyester formed from isophthalic and nonanedioic acids with diols and triols is provided.
While the above materials and processes may be suitable for their intended purposes; a need remains for photographic papers particularly suitable for use in electrophotographic applications utilizing oil-less fusers.
EP-A-0778500 composition and coating discloses a light-transmitting recording material for electrophotography, comprising a light-transmitting base material and a surface layer formed on the base material, wherein said surface layer contains a thermoplastic resin and a release agent having a melting point of from 40°C to 120°C. Suitable release agent include waxes.
US-A-5,968,689 relates to an image-forming material which can be removed easily from an image-receiving paper while maintaining the fixability to the image-receiving paper. The image-forming material comprises a binding resin, such as a polyester resin, and further a releasing agent, such as natural waxes.
US-A-5,437,913 discloses an electrophotographic transfer film comprising a transparent substrate having formed on at least one side thereof an image-receiving layer, which comprises a binder resin and at least one resistivity control agent selected from a conductive metal oxide fine particle and a non-ionic surface active agent. The binder resin may preferably be polyester resin.
EP-A-1124164 discloses an image-receiving sheet comprising a substrate sheet and an image-receiving layer, wherein the image-receiving layer is composed mainly of a polyester resin comprising an acid moiety and a diol moiety of a modified bisphenol A. An additional layer on top of the image-receiving sheet may comprise a particulate lubricant in a resin varnish, wherein the particulate lubricant may include petroleum waxes, polyethylene waxes and montan waxes.
WO-A-03/036392 discloses an electrophotographic recording medium comprising an opaque substrate having a surface coated with a toner-receptive layer. Said layer comprises a polyester resin and a wax having a melting point in the range of about 90°C to about 200°C.
It is a feature of the present invention to provide photographic papers with many of the advantages indicated herein.
The present invention provides a process for the production of a photopaper coating composition, the method comprising:

mixing up to about 40% by weight of a matrix of polyester with wax dispersed therein in a solvent under shear agitation, whereby the polyester dissolves and molecularly disperses within the solvent and the wax forms microparticles of up to 3 µm.

The present invention relates to a novel process for the production of a coating composition for application to photopaper used in oil-less colour engines. The coating composition forms a coating on the photopaper which coating resists sticking and wrapping on oil-less fuser rolls.
Aspects of the present invention relate to a process which comprises making a polyester/wax photopaper coating composition for use on a photopaper substrate suitable for use in an oil-less colour engine.
The present invention relates to a process for the production of a coated photographic paper comprised of a substrate, such as a cellulosic substrate, and a coating thereover of a polyester/wax composition and which coating is preferably thin, for example 1µm to 15 µm thickness, or from 1µm to 10 µm, or more preferably from 2 to 8 µm as measured by a thickness gauge, model MT-12 from Heidenhain, and wherein there is enabled uniform glossy images with such papers. More specifically, there are provided in accordance with the present invention processes for generating high, for example, from 50 to 100 gloss units (GU) as measured with a 75° Glossmeter, Glossgard from Pacific Scientific, and which gloss is uniform, that is it does not significantly vary, or change on the image, or wherein the differential gloss level is reduced or minimized. Furthermore, the coating provides a surface to the photopaper which does not adhere to an oil-less fuser roll.
The coating composition comprises an organic solvent having up to 40% by weight of a polyester and wax. The polyester is molecularly dispersed within the solvent whereas the wax is provided as micron sized particles. More preferably, the coating composition comprises from 10% to 40% by weight of the polyester and wax, and even more preferably is 15% to 25% by weight of the polyester and wax in the composition.
The coating composition is made by mixing solid particles In the form of a powder of a polyester/wax with a suitable organic solvent. The particles of powder comprise a suitable polyester resin and a suitable wax in a ratio of 98:2 to 85:15 by weight and more preferably from 96:4 to 90:10 by weight. The particles are 10 µm to 50 µm in diameter, more preferably 10 µm to 20 µm and most preferably 10 µm in size. It is understood by one of skill in the art that a mixture of sizes of particles of polyester/wax can be provided to make the composition so long as in general, the particle size ranges between 10 µm to 50 µm. The initial particles of polyester and wax added to the organic solvent are a matrix of polyester with the wax dispersed therein. As such, the polyester dissolves and molecularly disperses within the organic solvent under shearing conditions whereas the wax does not dissolve in the organic solvent under shearing conditions but rather forms microparticles of up to 3.0 µm in diameter and more preferably up to 2.0 µm.
The polyester forming part of the micro-particles of the coating composition may comprise a suitable polyester resin or similar polymer or mixtures of such. For example, the polyester may comprise more specifically a poly(propoxylated bisphenol A fumarate) resin, a polyester resin comprised of poly(terephthalic acid bisphenol-A-ethylene oxide adduct), cyclohexane dimethanol or a low, for example from 1,000 to 50,000, and preferably 20,000 M _w , branched copolyester formed from isophthalic and nonanedioic acids with diols and triols, such as resin, is Vitel 58338^™ polyester or Vitel 5833^™ available from the Bostik Company. Preferred diols are 2,2,4,4-tetraalkyl-1,3-cyclobutane diol, 1,4-butane diol, or 1,3-propane diol; and preferred triols are 2-(hydroxy methyl)1,3-propane diol, 1,1,1(trishydroxy methyl)ethane, 1,2,4-butane triol, or 1,2,3-propane triol. Other suitable coatings may be selected, such as known polyesters and mixtures thereof, inclusive of the polyesters of, for example, U.S. Pat. No. 3,590,000 .
Suitable wax for use in the polyester/wax micro-particles of the coating composition may comprise montanic ester waxes, montanic acid waxes, stearamide waxes, carnauba waxes and mixtures thereof. Exemplitive examples of such waxes include but are not limited to: Licowax F^™ (a Montanic Ester wax supplied by the Clariant Corporation), Licowax E^™ (a Montanic Ester wax supplied by the Clariant Corporation), Licowax S^™ (a Montanic Acid wax supplied by the Clariant Corporation), Licowax LP^™ (a Montanic Acid wax supplied by the Clariant Corporation), Kemamide W40^™ (a Stearamide wax supplied by C.K. Witso), Hymicron G270^™ (a Stearamide wax supplied by Chukyo Yushi Company), Hymicron H982^™ (a Carnauba wax supplied by Chukyo Yushi Company) and SL506^™ (a Carnauba wax supplied by Elementis Specialties).
Any suitable substrate can be employed in the invention. The substrates selected may be commercially available photopaper as ink jet, off set or xerographic papers. In one aspect, the substrate is a cellulosic substrate and is comprised of alkaline sized and acid sized blends of hardwood kraft and softwood kraft fibers, which blends contain from 10 percent to 90 percent by weight of softwood and from 90 to 10 percent by weight of hardwood. Examples of hardwood include SeaGUII W dry bleached hardwood kraft, preferably present, for example, in one embodiment in an amount of 70 percent by weight. Examples of softwood include La Toque dry bleached softwood kraft present, for example, in one embodiment in an amount of 30 percent by weight. These sized substrates may also contain pigments in effective amounts of from 1 to 60, and preferably from 1 to 25 percent by weight, such as clay (available from Georgia Kaolin Company, Astro-fil 90 clay, Engelhard Ansilex clay), titanium dioxide (available from Tioxide Company--Anatase grade AHR), calcium silicate CH-427-97-8 , XP-974 (J.M. Huber Corporation), and the like. Also, the sized substrates may contain various effective amounts of sizing chemicals (for example from 0.25 percent to 25 percent by weight of pulp), such as Mon size (available from Monsanto Company), Hercon-76 (available from Hercules Company), Alum (available from Allied Chemicals as Iron free alum), and retention aid (available from Allied Colloids as Percol 292). The sizing values of papers, including the commercial papers that can be selected for the present invention in embodiments thereof, vary between, for example, 0.4 second to 4,685 seconds, and papers in the sizing range of 50 seconds to 300 seconds are preferred, primarily to decrease costs. The porosity values of the substrates, which are preferably porous, vary from 2,54x10^-3 m/minute to 0,032 m/minute (100 to 1,260 mil/minute) and preferably from 2,54x10^-3 m/minute to 0,015 m/minute (100 to 600 mil/minute) to permit, for example, the use of these papers for various printing technologies, such as thermal transfer, liquid toner development, xerography, ink jet processes, and the like.
Illustrative examples of commercially available, internally and externally (surface) sized substrates that may be selected for the present invention, and which are treated with a de-sizing agent dispersed in an optional binder with a substrate thickness of, for example, from 50 µm to 200 µm (50 microns to 200 microns) and preferably of a thickness of from 100 µm to 175 µm (100 microns to 175 microns) include Diazo papers, offset papers such as Great Lakes offset, recycled papers such as Conservatree, office papers such as Automimeo, Eddy liquid toner paper and copy papers from companies such as Nekoosa, Champion, Wiggins Teape, Kymmene, Modo, Domtar, Veitsiluoto and Sanyo with Xerox 4024.TM. papers and sized calcium silicate-clay filled papers being particularly preferred in view of their availability, and low print through.
Any suitable solvent may be used in the composition. Suitable solvents for use in the present invention include but are not limited to toluene, methyl ethyl ketone, isopropanol, dioxolane and mixtures thereof. Preferably, the solvent is selected from the group consisting of toluene and methyl ethyl ketone, toluene and isopropanol; toluene and dioxolane; and methyl ethyl ketone, dioxolane and isopropanol. A preferred solvent system is toluene/methyl ethyl ketone (MEK) with the ratio of toluene to methyl ethyl ketone being in the range of 80:20 to 30:70 by weight and more preferably in the ratio of 70:30 to 50:50 by weight. Other suitable solvent systems may include for example toluene/isopropanol (in a ratio of 80:20 to 30:70 by weight), toluene/dioxolane (in a ratio of 80:20 to 30:70 by weight) and methyl ethyl ketone/dioxolane/isopropanol (in a ratio of 45:45:10 by weight).
In an aspect of the invention, the photopaper coating composition is made by the mixing of up to 40% by weight, more preferably 10 % to 40% by weight, and more preferably 15% to 25% by weight of the polyester/wax 10 µm to 50 µm in diameter particles in a suitable organic solvent under moderate shear agitation. As such, the polyester dissolves into the organic solvent. The wax as presented within the micro-particles of polyester/wax does not dissolve in the organic solvent but rather forms small microparticles during shearing. The coating composition is then filtered through a suitable bag filter such as a 25 µm bag filter and collected.
The coating composition is then applied in a thin layer to a desired substrate using a slot coating head to form a coating on the substrate. The coating composition as applied to the substrate is dried to provide a dry, adherent coating on the substrate having a thickness of up to 10 µm and more preferably 2 µm to 8 µm. Drying is achieved at a temperature and time sufficient that the wax particles move more to the surface of the coating. In this manner, the coating as provided on the substrate adheres well to the selected substrate such that it is not removable therefrom. The resultant coating comprises polyester having particles of wax of up to 2 µm in diameter dispersed throughout. In one embodiment over 90% of the wax particles of the coating are up to 2 µm. More preferably, over 95% of the wax particles of the coating are up to 2 µm. Even more preferably, over 98% of the wax particles of the coating are up to 2 µm and even more preferably, over 99% of the wax particles of the coating are up to 2 µm.
The coating composition as applied to a desired substrate to form a coating and used in a xerographic oil-less fuser, will not stick to the oil-less fuser roll and yet provide images with high uniform gloss. Furthermore, the coated photopapers of the present invention exhibit good qualities of reduced curl upon printing and can be used with a variety of different toners as recited in Applicant's U.S. Patent No. 6,177,222 .
Specific embodiments of the invention will now be described in detail. All parts and percentages are by weight unless otherwise indicated.

EXAMPLES

The variation in gloss level of a xerographic color print can be quantified by using a specially devised differential gloss test target. The test target consists of an 0.2 m by 0.27 m (8 and 1/2 by 11 inch) sheet having nine equally sized squares of 5 centimeter dimension evenly spaced around the area of the sheet.
The nine squares have varying optical density which is achieved by varying the toner coverage on each square as follows: 0 percent coverage (substrate only), 10 percent coverage, 20 percent coverage, 40 percent coverage, 60 percent coverage, 80 percent coverage, 100 percent coverage, the color green (2 layers of toner) and process black (3 layers of toner). A print of this test target is then produced on a xerographic color copier/printer using a given substrate. The gloss level of the nine squares on the resulting xerographic print is measured using a 75° Glossmeter. The variation in gloss level is then defined as the difference in gloss between the highest and lowest gloss values obtained from the nine squares of varying toner coverage.

EXAMPLE 1

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 60% toluene and 40% methyl ethyl ketone under moderate shear agitation for approximately two hours of mixing. The final coating solids were about 25% by weight. The resin used in the coating was Vitel 5856B™, a low molecular weight non-crystalline polyester. The wax was selected from montanic acid waxes and Licowax S™ was specifically used. The ratio of resin to wax was 92:8.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 8 2.4 m/min (fpm). Drying was achieved using two banks of air-impingement dryers both operated at 135°C. Dry coating thickness applied was about 8 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 70 GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).
The fused sheets were further tested in an oil-less prototype unit specifically developed for photo-finishing applications. The unit consisted of a heated, smooth, seamless belt with a cooling zone The prototype unit increased the gloss level of the prints, further reduced differential gloss and eliminated toner contouring. The Faustel coated sheets that were imaged and fused in Xerox DC2006 printer were passed through the prototype unit. The prints released freely from the oil-less prototype belt with no transfer of material. The resulting prints had high absolute gloss (75° gloss = 99GU), extremely low differential gloss (less than 1GU) and no visible toner contouring or image defects.

EXAMPLE 2

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 60% toluene and 40% methyl ethyl ketone under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 30% by weight. The resin used in the coating was Vitel 5856B™, a low molecular weight non-crystalline polyester. The wax was selected from montanic acid waxes and Licowax S™ was used. The ratio of resin to wax was 94:6.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers both operated at 135°C. Dry coating thickness applied was about 6 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 70 GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

EXAMPLE 3

Coating solution was prepared by adding a resin/wax particles to a solvent mixture of 60% toluene and 40% methyl ethyl ketone under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 25% by weight. The resin used in the coating was a 50:50 mixture by weight of Vitel 5856B™ and Vitel 2200™. The wax was selected from montanic acid waxes and Licowax S™ was used. The ratio of resins to wax was 92:8.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers one operating at 50°C and the other at 105°C. Dry coating thickness applied was about 5 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 80 GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

EXAMPLE 4

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 60% toluene and 40% methyl ethyl ketone under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 25% by weight. The resin used in the coating was a 75:25 mixture of Vitel 5856B™ and Vitel 2200™. The wax was selected from montanic acid waxes and Licowax S™ was used. The ratio of resins to wax was 94:6.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers one operating at 50°C and the other at 105°C. Dry coating thickness applied was about 8 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 75 GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

EXAMPLE 5

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 50% toluene and 50% methyl ethyl ketone under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 25% by weight. The resin used in the coating was Vitel 5856B™, a low molecular weight non-crystalline polyester. The wax was selected from carnauba waxes and SlipAyd SL506™ was used. The ratio of resin to wax was 93:7.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers both operated at 135°C. Dry coating thickness applied was about 6 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 85GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

EXAMPLE 6

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 50% toluene and 50% methyl ethyl ketone under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 25% by weight: The resin used in the coating was Vitel 5856B™, a low molecular weight non-crystalline polyester. The wax was selected from montanic ester waxes and Licowax F™ was used. The ratio of resin to wax was 93:7.
The coating was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers both operated at 135°C. Dry coating thickness applied was about 6 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 70GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

EXAMPLE 7

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 60% toluene and 40% methyl ethyl ketone under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 25% by weight. The resin used in the coating was Vitel 5856B™, a low molecular weight non-crystalline polyester. The wax was selected from montanic ester waxes and Licowax E™ was used. The ratio of resin to wax was 94:6.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers one operating at 50°C and the other at 105°C. Dry coating thickness applied was about 9 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 65GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

EXAMPLE 8

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 60% toluene and 40% isopropanol under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 25% by weight. The resin used in the coating was Vitel 5856B™, a low molecular weight non-crystalline polyester. The wax was selected from montanic ester waxes and Licowax KLE™ was used. The ratio of resin to wax was 94:6.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers one operating at 100°C and the other at 135°C. Dry coating thickness applied was about 8 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 65GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

EXAMPLE 9

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 50% toluene and 50% dioxolane under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 25% by weight. The resin used in the coating was Vitel 5856B™, a low molecular weight non-crystalline polyester. The wax was selected from montanic acid waxes and Licowax S™ was used. The ratio of resin to wax was 95:5.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.07x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers both operating at 135°C. Dry coating thickness applied was about 7 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 75GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

EXAMPLE 10

Coating composition was prepared by adding a resin/wax particles to a solvent mixture of 45% methyl ethyl ketone, 45% dioxolane and 10% isopropanol under moderate shear agitation for approximately two hours of mixing. The final coating solids was about 25% by weight. The resin used in the coating was Vitel 5856B™, a low molecular weight non-crystalline polyester. The wax was selected from carnauba waxes and SlipAyd SL503™ was used. The ratio of resin to wax was 96:4.
The coating composition was filtered through a 25 µm bag filter into a stainless steel pressure pot. The coating substrate was a #1 Offset C2S Offset (162 gsm Centure Gloss Cover manufactured by Consolidated Paper Inc.). Coating was applied on a Faustel Model TT coater using a slot coating head. The slot width was 1.02x10^-4 m (4 mil), die gap 7.6x10^-5 m (3 mil), web speed 2.4 m/min (8 fpm). Drying was achieved using two banks of air-impingement dryers both operating at 135°C. Dry coating thickness applied was about 6 µm. The final coating quality was uniform and without defect. The gloss of the final coated sheet was approximately 70GU (60° Gardiner gloss).
The Faustel coated sheets were evaluated in three different oil-less fusers: 1) NICE, which is an oil-less version of fuser used in Xerox DC12 printer, 2) the oil-less fuser used in Xerox DC2006 printer and 3) the oil-less fuser used in Xerox Phaser 7700 printer. The sheets did not stick or wrap on any of the oil-less fusers and there was no transfer of coated material to the fuser rolls. The resulting fused sheets had a high level of gloss (75° gloss>90GU).

Claims

A process for the production of a photopaper coating composition, the method comprising:
- mixing up to about 40% by weight of a matrix of polyester with wax dispersed therein in a solvent under shear agitation, whereby the polyester dissolves and molecularly disperses within the solvent and the wax forms microparticles of up to 3 µm.
The process of claim 1, wherein said polyester matrix comprises polyester/wax particles of 10 µm to 50 µm in diameter.
The process of claim 1 or 2, wherein said composition comprises 98:2 to 85:15 by weight of polyester to wax.
The process of claims 1 or 2, wherein said polyester is a polyester selected from the group consisting of a polyester of poly(propoxylated bisphenol A fumarate), a polyester resin composed of terephthalic acid/bisphenol A ethylene adduct/cyclohexane dimethanol or low molecular weight, branched copolyesters formed from isophthalic and nonanedioic acids with diols and triols and mixtures thereof.
The process of claims 1 or 2, wherein said solvent is selected from the group consisting of toluene, methyl ethyl ketone, isopropanol, dioxolane and mixtures thereof, and/or wherein said wax is selected from the group consisting of montanic ester waxes, montanic acid waxes, stearamide waxes, carnuba waxes and mixtures thereof.
The process of claims 1 or 2, wherein the method comprises the mixing of 15% to 25% by weight of the matrix.