WO2000063307A1 - A water-in-oil emulsion digital duplicating ink - Google Patents

A water-in-oil emulsion digital duplicating ink Download PDF

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Publication number
WO2000063307A1
WO2000063307A1 PCT/GB2000/001519 GB0001519W WO0063307A1 WO 2000063307 A1 WO2000063307 A1 WO 2000063307A1 GB 0001519 W GB0001519 W GB 0001519W WO 0063307 A1 WO0063307 A1 WO 0063307A1
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WIPO (PCT)
Prior art keywords
ink
oil
water
phase
weight
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PCT/GB2000/001519
Other languages
French (fr)
Inventor
Wan Kang Zou
Clement N. Onyenemezu
Xiaomang Wang
Original Assignee
Marconi Data Systems Inc.
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Publication date
Application filed by Marconi Data Systems Inc. filed Critical Marconi Data Systems Inc.
Priority to AU41307/00A priority Critical patent/AU4130700A/en
Publication of WO2000063307A1 publication Critical patent/WO2000063307A1/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/02—Printing inks
    • C09D11/023—Emulsion inks
    • C09D11/0235—Duplicating inks, e.g. for stencil printing

Definitions

  • the present invention relates to water-in-oil emulsion duplicating inks used in digital
  • Emulsion inks are generally used in digital duplicating processes. In those processes, the ink is introduced into a cylinder having a plurality of small holes. The circumferential wall of the cylinder is formed with such holes, and a stencil is wrapped around the cylinder. During the printing process, the ink penetrates through the holes in the cylinder and the selectively formed image openings in the stencil onto the surface of a paper. The paper is held in contact with the cylinder and stencil by means of a platen roller.
  • Emulsion inks are formulated with an oil phase and an aqueous phase.
  • the oil phase generally contains drying oils.
  • the colorant is dispersed either in the oil phase or in the water phase.
  • the fibers of the paper have numerous small pores, which act to break down the two phases in the ink as the ink is absorbed into the paper.
  • the water in the aqueous phase diffuses through the paper leaving behind the carbon black on the surface.
  • the drying oils of the oil phase dry and form a film on the carbon black and immobilize the carbon black on the paper to produce a permanent image.
  • the ink of US-5,622,548 is well suited for its intended purpose, it has certain drawbacks when used in certain specific applications.
  • the ink of US-5,622,548 is not particularly well suited for use in a Risograph digital duplicator.
  • the inks of US-5,622,548 do not exhibit any significant gel structure, typically having a yield stress of about 950- 1 ,200 dynes/cm 2 and a consistency index of about 60,000-82,000.
  • the ink tends to leak out from the tail of the stencil.
  • the low ink gel structure also causes the Risograph duplicator to lay down too much ink onto the paper, causing setoff, showthrough, rub off, slow dry time, and low printing yield.
  • a particular goal of the present invention was to provide an ink that would exhibit good emulsion stability and ink shelf life, and provide printed images with good rub resistance and image quality when used in a Risograph digital duplicator.
  • a water-in-oil emulsion ink for use in digital duplicators comprising an oil phase and a water phase, the oil phase comprising a colorant and optionally a film-forming component, and the water phase comprising water.
  • the ink of the present invention comprises one or more additional components selected from the group consisting of (1) phenolic modified esters of rosin, (2) gelled oils, (3) co-emulsifiers, and (4) a non- drying oil or a combination comprising a non-drying vegetable oil and petroleum distillate.
  • the ink formulations of the present invention exhibit higher yield stress (ink gel structure), a higher plastic viscosity, a higher consistency index and a lower flow index than the ink of US-5,622,548.
  • the inks of the present invention exhibit a yield stress of about 2,000 to about 8,000 dynes/cm 2 , a consistency index of about 100,000 to about 500,000 and a flow index of about 0.20 to about 0.40.
  • the plastic viscosity will be from about 6,000 to about 20,000
  • the present invention also provides an improved digital duplicating process for producing images having high color strength, high image density, good image resolution, low set-off, low "bleed through”, excellent runnability, and better environmental stability, wherein the improvement comprises using an ink comprising an oil phase and a water phase, the oil phase comprising a colorant and optionally a film-forming component, and the water phase comprising water.
  • the ink of the present invention comprises one or more additional components selected from the group consisting of (1) phenolic modified esters of rosin, (2) gelled oils, (3) co-emulsifiers, and (4) non-drying oils or combinations comprising a non-drying vegetable oil and petroleum distillate. Preferred embodiments of the present invention will now be described.
  • the present invention provides water-in-oil emulsion ink formulations suitable for use in digital duplicators that offer high color strength, high image density, good image resolution, low set- off, low "bleed through”, excellent runnability, and good environmental stability.
  • the water-in-oil emulsion ink formulation of the present invention comprises an oil phase and a water phase, the oil phase comprising a colorant, which may be an encapsulated colorant, and the water phase comprising water.
  • the water-in-oil ink emulsions of the present invention exhibit physical characteristics that make them more suited to use in a Risograph digital duplicator. These improved physical characteristics are achieved by use of one or more of the following components: (1) phenolic modified esters of rosin, (2) gelled oils, (3) co-emulsifiers, and (4) a non-drying oil or a combination comprising a non-drying oil and petroleum distillate.
  • the gel structure of the present water-in-oil emulsion ink is achieved through the use of gelling and/or thickening agents in the oil phase; preferably there is sufficient gelling and/or thickening agent in the oil phase to result in an ink having a yield stress of about 2,000 to about 8,000 dynes/cm 2 and a consistency index of about 100,000 to about 500,000.
  • the water phase is substantially free of gelling and thickening agents.
  • the gel structure of the water-in-oil emulsion results from the components in the oil phase as opposed to components of the water phase.
  • Any phenolic modified ester of rosin can be used.
  • suitable phenolic modified esters of rosin include Filtrez 625N, Filtrez 623, Filtrez 686, Filtrez 681, and Filtrez 657, available from AKZO NOBEL Resin and Vehicle, Matteson, IL., and Ultra-RezTM 135, Ultra-RezTM 150,
  • Ultra-Rez 165 and Ultra-Rez 175, available from Lawter International, Inc., Northbrook, IL.
  • Filtrez 681 which has a softening point of 160°C to 170°C, is preferred.
  • Filtrez 681 is a phenolic modified rosin pentaerythritol ester.
  • the phenolic modified ester of rosin improves the ink setting time, the drying time, setoff, showthrough, rub resistance and high speed printing performance.
  • the phenolic modified ester of rosin is usually present in an amount from about 0 to about 8 percent, based on the total weight of the ink emulsion.
  • the phenolic modified ester of rosin will be present in an amount of about 2 to about 5 percent.
  • any gelled oil can be used.
  • suitable gelled oil include gelled petroleum oil, gelled hydrotreated petroleum oil, gelled paraffinic oil, gelled naphthenic oil, gelled paraffinic process oil, gelled naphthenic process oil, and gelled vegetable oil.
  • Gelled technical grade white oil such as Extac 52, Extac 47 or Extac 60 are preferred.
  • the gelled oil helps to build the gel structure of the ink and is usually present in an amount from about 0 to about 15 percent, based on the total weight of the ink. Preferably, the gelled oil will be present in an amount of about 2 to about 8 percent.
  • Any emulsifiers can be used as a co-surface active agent to improve the ink stability and shelf life.
  • One such suitable co-surface active agent is lecithin. Any grade and supplier of lecithin may be used. Actiflo 68UB, which has an acid value of 23, and Centrol 2FUB, which has an acid value of 28, are preferred.
  • the lecithin improves the ink stability and shelf life and is usually present in an amount from about 0 to about 8 percent, based on the total weight of the ink.
  • the co-surface active agent will be present in an amount of about 1 to about 5 percent.
  • non-drying oils or non-drying oil combination can be used.
  • suitable non- drying oils include petroleum distillate, hydrotreated petroleum oil, paraffinic oil, naphthenic oil, paraffinic process oil, naphthenic process oil, technical grade white oil, and non-drying vegetable oil.
  • One or a combination of oils can be employed.
  • the vegetable oil is preferably Agrisolv H
  • the petroleum distillate is preferably selected from the Sunpar series, mineral seal oil or Isopar series, such as Sunpar 115, Sunpar 120, Sunpar 130, Sunmpar 150, and Isopar L.
  • the non-drying oils or a combination of oils improves open time, dry time for the ink and assists in optimizing ink rheology.
  • the oils may be used in various ratios, and are usually present in an amount from about 0 to about 60 percent, based on the total weight of the ink.
  • the non-drying oil or non- drying oil combination will be present in an amount of about 5 to about 35 percent.
  • the colorant may be a dye or a pigment.
  • the colorant may be organic or inorganic.
  • suitable colorants which optionally may be encapsulated and used in accordance with the present invention include C.I. Blue 15:3, available as Process Blue Pigment 249-2083 from Sun Chemical Corp., and the C.I. Green 7, available as Green Pigment 264- 8142 from Sun Chemical Corp., C.I. Violet 1, which is a Rhodamine B PTMA type pigment and available from Magruder Color Company in Elizabeth, New Jersey, as MM 0107-DC, and carbon black.
  • the types of carbon black include Channel black, furnace black, and lamp black.
  • any suitable carbon black can be used in the preparation of the ink and the encapsulated colorant of the present invention.
  • the carbon black has a BET surface area of from about 20 square meters per gram to about 600 square meters per gram, and a dibutylphthalate (DBP) oil absorption of from about 20 cc/100 gm to about 200 cc/100 gm.
  • DBP dibutylphthalate
  • MONARCHTM 120, MONARCH 280, REGALTM 250R, and REGAL 350R from Cabot Corporation are examples of preferred carbon black colorants.
  • MONARCH 120 is a lamp type carbon black having a particle size of 0.075 microns, a BET surface area of 25 square meters per gm, and a DBP oil absorption of 64 cc/100 gm.
  • MONARCH 280 is a lamp type carbon black having a particle size of 0.045 microns, a BET surface area of 42 square meters per gm, and a DBP oil absorption of 121 cc/100 gm.
  • REGAL 250R has a particle size of 0.035 microns, a BET surface area of 50 square meters per gm, and a DBP oil absorption of 46 cc/100 gm.
  • REGAL 35 OR is a blue-toned carbon black. More examples of preferred carbon black colorants include Printex 300, Printex 25, and special black 250 from Degussa Corporation.
  • suitable colorants also include commercial available pigment dispersions (Flush), such as sheet-fed black base SFK-135, SFK-218, SW-6100, SW-6300, SW-6500, SW-6800, and RFK-236 quality forms black base available from Continental Dispersions, Inc., West Chicago, Illinois, Q.S. Black #7187, Q.S. Black QB-6807S, and Q.S. Black QB-6824 available from ACRO, Inc., Fennville, Michigan, and 40 Plus Base Black and 40 Plus "EZ" Base Black available from Kerly Ink, Broadview, Illinois. More examples of suitable colorants also include aforedescribed colorant alone. These colorants can be directly used in the oil phase to prepare the water-in-oil
  • Suitable colorants include metallized azo reds such as Red 49:1 (barium salt), Red 49:2 (calcium salt), Red 63:1 (calcium salt), toluidine reds, naphthol reds, pyrazalones, rhodamines, quinacridones such as Red B, Red Y, Magenta B, Magenta and Violet, phthalocyanine blues, phthalocyanine greens, carbazole yellow, monoarylide yellow, diarylide yellow, chrome yellow, red lake C, lithol reds such as calcium and barium salts, lithol rubine, bon maroon, perylene pigments, Red 2B pigments including the calcium, barium and magnesium salts, chrome yellow, chrome orange, molybdate orange, lead chromes, lead silicochromates, zinc chromes, barium chromate, strontium chromate, titanium nickel yellow, liminites, haematite, magnetite, micaceous oxides of iron, siderite, iron metall
  • Any suitable amount of the aforedescribed colorant can be used in the preparation of the ink.
  • the ink is typically used in an amount of from about 3% by weight to about 35% by weight of the ink, and preferably in an amount of from about 4% by weight to about 20% by weight of the ink. Excessive use of the colorant will adversely affect the image quality, for instance, the image resolution will decrease and image set-off will increase.
  • the encapsulated colorant preferably comprises a colorant having a particle size of from about 0.01 microns to about 25 microns, preferably having a particle size of from about 0.01 microns to about 5 microns, an adhesion promoter, and at least one binder resin usually selected from the group consisting of a hydrocarbon modified rosin ester and a phenol modified hydrocarbon resin.
  • the encapsulated colorant can be prepared by any suitable method. It is preferably prepared in accordance with the method of U.S. Patent No. 5,622,548. In accordance with that method a suitable colorant is combined with an oil component, a binder resin component, and preferably an adhesion promoter and a disperser vehicle. The components of the encapsulated colorant are combined sequentially and mixed in a suitable mixer or blender until a uniformly mixed encapsulated colorant is produced. A detailed discussion of the various components of the encapsulated colorant is set forth in U.S. Patent No. 5,622,548.
  • the oil phase comprises one or more oils. Any suitable oil, including saturated and unsaturated, can be used.
  • the oil may be used to prepare the encapsulated colorants or optionally may be directly used in the oil phase of the ink when the dispersed colorant or colorant alone are used.
  • the saturated oil preferably has a boiling point of from about 280°C to about 420°C and a viscosity of from about 300 Saybolt Universal Standard (SUS) to about 2400 SUS at 100°F.
  • suitable saturated oils include aromatic, naphthenic, and paraffinic oils.
  • suitable aromatic oils include FLEXONTM 340 and FLEXON on 391, SUNDEXTM 790 and SUNDEX 8600T, and TUFFLOTM 491.
  • naphthenic oils examples include CIRCOSOLTM 450, CIRCOSOL 4240, CIRCOSOL 5600, SUNTHANETM 450, SUNTHANE 4240, FLEXON 676, FLEXON 766, TUFFLO 500, TUFFLO 750, TUFFLO 2000, TUFFLO 6024, and examples of paraffinic hydrocarbon include SUNPAR 150, SUNPAR 2280, FLEXON 815, FLEXON 865, TUFFLO 60 and TUFFLO 80.
  • a preferred oil is TUFFLO 2000, which has a viscosity of 2117 SUS at 100°F, boiling point of 320°C, an acid number of 0.05 mg KOH/g, and a color index of 2.5.
  • TUFFLO brand oils are available from EMCO Chemical Distributors, Inc. in Northbrook, 111.
  • CIRCOSOL, SUNTHANE, SUNPAR, and SUNDEX brand oils are available from Sun Oil Co., in
  • suitable unsaturated oils include ground nut, cashew nut, castor, chia, corn (maize), cotton seed, hemp, linseed, lumbang, niger seed, oiticia, perilla, poppy, po-yok, safflower, soya, stillingia, sunflower, tobacco seed, tung, and walnut oils, and combination thereof, with the soybean oil and linseed oil being examples of preferred oils.
  • the oil may be used in any suitable amount. It is typically used in an amount of from about 10% by weight to about 60% by weight of the encapsulated colorant, and preferably in an amount of from about 20% by weight to about 45% by weight of the encapsulated colorant. Excessive use of the oil will increase drying times undesirably.
  • the oil component may also include one or more of viscosity adjusting agents such as low viscosity aliphatic oils, naphthenic oils, and tall oil fatty esters.
  • the viscosity adjusting agents preferably have a viscosity of from about 3.0 CST @ 104°F (or 36 SUS @ 100°F) to about 4.0 CST @ 104°F (or 39 SUS @ 100°F), and more preferably a viscosity of from about 3.4 to about 3.6 CST @ 104°F.
  • Mineral seal oil a preferred viscosity adjusting agent and available from EMCO Chemical Distributors, Inc., is an aliphatic oil having a boiling point of 250°C, an acid number of 0.01 mg KOH/g, and a viscosity of 3.53 CST @ 104°F.
  • higher boiling viscosity adjusting agents may be utilized.
  • tall oil fatty acid esters such as CrC 8 alkyl and mono-, di- and trialkylene glycol esters of tall oil fatty acids, can be used as the viscosity adjusting agents.
  • tall oil fatty acid esters are commercially available. For example, NIREZTM brand tall oil fatty acid esters are available from Arizona Chemical Company Co. in Panama City, Fla.
  • NIREZ 9011 which is a methyl ester of tall oil fatty acid and has a Brookfield viscosity of 7 centipoises (cps), an acid number of 5 mg KOH/g, an iodine value of 105 minutes (Wijs), and a EPA-24 volatiles content of 8%
  • NIREZ 9012 which is a butyl ester of tall oil fatty acid and has a Brookfield viscosity of 7 cps, an acid number of 2 mg KOH/g, an iodine value of 110 minutes, and a EPA-24 volatiles content of 2%
  • NIREZ 9015 which is a butyl ester of tall oil fatty acid and has a Brookfield viscosity of 8 cps, an acid number of 14 mg KOH/g, an iodine value of 112 minutes, and a EPA-24 volatiles content of 2%
  • NIREZ 9007 which is a 2-ethyl ester of tall oil fatty acid and
  • the viscosity adjusting agent may be used in any suitable amount in the preparation of the encapsulated colorant.
  • the viscosity adjusting agent is generally used in an amount of from above 0% by weight to about 25% by weight, and preferably in an amount of from about 8% by weight to about 12% by weight of the encapsulated colorant. Excessive use of the viscosity adjusting agent will result in too low of a viscosity and a yield value of the ink that produces a poor image resolution and poor runnability.
  • the oil phase may preferably include a suitable surface active agent to facilitate and stabilize the emulsion.
  • the surface active agent may also reduce the surface tension energy of the oil phase, thereby increasing the drying rate of the ink.
  • Any suitable surface active agent may be used, including anionic, cationic, nonionic, amphoteric surface active agents, and combinations thereof. Nonionic surface active agents are preferred.
  • nonionic surface active agents include fatty acid esters of sorbitan such as sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan sesquioleate, sorbitan trioleate, sorbitan monoolaurate, sorbitan dilaurate, sorbitan trilaurate, and fatty acid triglycerides such as oleic acid monoglyceride, oleic acid diglyceride, polyethylene oxide adducts of fatty acids such as polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, and ethylene oxide adducts of alkyl phenols and higher alcohols.
  • sorbitan monooleate such as sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan sesquioleate, sorbitan
  • the surface active agent can be used in any suitable amount. It is typically used in the oil phase in an amount of from about 0.5% by weight to about 8% by weight of the ink, and preferably in an amount of from about 1% by weight to about 3% by weight of the ink. Excessive use of the surface active agent is to be avoided because the excess surface active agent will diffuse through the paper and make it transparent, and destabilize the emulsion.
  • the oil phase preferably comprises a film-forming component.
  • the film-forming component rapidly forms a tough and durable film on the colorant particle, immobilizes the colorant on the paper, and helps produce images of high color strength and good image resolution.
  • Any suitable film-forming component compatible with the oil phase oils may be used as the film-forming component.
  • suitable film-forming components are hydrocarbon resins such as polyolefin resins and terpene resins, polyester resins such as alkyd resins, and unsaturated polyester resins such as the resins prepared from the condensation polymerization of a glycol such as 1 :2- propylene glycol or 1 :3-butylene glycol with an unsaturated acid such as maleic acid.
  • Suitable terpene resins include those having a number average molecular weight (Mn) of from about 500 to 5,000, and preferably those having an Mn of from about 600 to about 1000. It is further preferred that the terpene resin has a melting point or softening point of from about 80°C to about 150°C, and it is further preferred that the terpene resin has a melting point or softening point of from about 100°C to about 140°C. Examples of suitable terpene resins include PICCOL YTETM 115 and PICCOL YTE 135, which are available from Hercules, Inc. in Wilmington, Delaware.
  • PICCOL YTE 115 has a softening point of 115°C (Ring and Ball or R&B), a glass transition temperature of 59°C (onset), a Mn of 625, a Mw/Mn of 1.8, and an acid number of 0.0 mg KOH/g.
  • PICCOLYTE 135 has an R&B softening point of 131 °C, a glass transition temperature of 81°C (onset), a Mn of 750, and a Mw/Mn of 1.6.
  • Alkyd resins are fatty acid esters of drying oils such as the unsaturated oils obtained from ground nut, cashew nut, castor, chia, com (maize), cotton seed, hemp, linseed, lumbang, niger seed, oiticia, perilla, poppy, po-yok, safflower, soya, stillingia, sunflower, tobacco seed, tung, and walnut.
  • unsaturated fatty acids present in the aforesaid drying oils include linolenic acid, linoleic acid, oleic acid, and ricinoleic acid.
  • the alkyd resins can be prepared by any method known to those of ordinary skill in the art including, for example, by esterification or ester interchange reaction of a mixture of the fatty acid, a polybasic acid, and a polyhydric alcohol.
  • suitable polybasic acids include the compounds having 2 to 4 carboxyl groups or methyl carboxylate groups per molecule such as phthalic acid or anhydride, isophthalic acid, terephthalic acid, maleic acid or anhydride, fumaric acid or anhydride, pyromellitic acid or anhydride, trimellitic acid or anhydride, benzene tetracarboxylic dianhydride, succinic acid or anhydride, sebacic acid, azelaic acid, dodecanedicarboxylic acid, dimethyl isophthalate, dimethyl terephthalate, and the like, and combinations thereof.
  • suitable polyhydric alcohols include ethylene glycol, propylene glycol, propane triol, glycerol, neopentyl glycol, 1 ,6-hexanediol, trimethylolpropane, sorbitol, tricyclodecanedimethanol, and
  • suitable amounts of phthalic anhydride and glycerol are heated to 180°C to the "first stage" syrup having residual or free hydroxyl groups, and molten fatty acids are added to esterify the free hydroxyl groups. Heating is continued at 180°C to 220°C until the desired acid number and solubility characteristics are reached.
  • the three raw materials, phthalic anhydride, glycerol, and fatty acid are placed in a reaction vessel together with a small quantity of xylol.
  • the vessel is fitted with a condenser to which is attached a water separator of the Dean Stark type.
  • the water produced is carried off with the xylol and is separated.
  • the condensing xylol serves to flush the sublimed phthalic anhydride back into the reaction vessel.
  • the amount of water collected is an indication of the progress of esterification, but samples of the resin are removed from time to time and for acid number and viscosity checks.
  • the reaction vessels are generally of stainless steel fitted with stirrer, charge hole, condensing system, and pipes for passing inert gas over the charge.
  • the latter serves to reduce discoloration.
  • Heating can be provided by any known means including by immersion heaters, and by passing hot fluids such as hot liquid or gas through a jacket surrounding the vessel.
  • An example of a hot liquid is a hot oil.
  • the necessity of isolating the fatty acids can be avoided in the preparation of glycerol type resins by the use of monoglycerides which are then further esterified with phthalic anhydride.
  • the monoglycerides are formed by heating the drying oil with the necessary amount of glycerol to about 250°C to about 280°C when the fatty acid triglyceride undergoes alcoholysis to form the monoglyceride.
  • the phthalic anhydride is added and the reaction completed at about 180°C to about
  • a preferred alkyd resin is a modified tall oil fatty acid ester that is capable of forming a fast- forming film on the encapsulated colorant during the duplicating process and provides a film that is tough and durable.
  • Tall oil fatty acid is essentially linoleic acid, and is derived from wood-pulp. It is preferred that the tall oil is virtually free of rosin acids so that the tall oil fatty acid can be used to produce a resin which is non-yellowing and exhibits excellent gloss.
  • the modification comprises an aromatic polycarboxylic acid. It is believed that the aromatic moiety imparts toughness and durability to the film.
  • aromatic polycarboxylic acids include aromatic compounds having 2 to 4 carboxyl groups in the free acid, anhydride, or lower alkyl ester form per molecule, such as phthalic acid, phthalic anhydride, or alkyl phthalate ester, isophthalic acid, terephthalic acid, pyromellitic acid or anhydride, trimellitic acid or anhydride, and benzene tetracarboxylic dianhydride.
  • An example of a preferred aromatic polycarboxylic acid is isophthalic acid.
  • the aromatic polycarboxylic acid content of the modified alkyd resin is preferably in an amount of from about 1% by weight to about 20% by weight of the alkyd resin, and is more preferably in an amount of from about 5% by weight to about 15% by weight, and most preferably in an amount of from about 9% by weight to about 12% by weight of the alkyd resin.
  • An example of a preferred alkyd resin is G-4495-100TM, an isophthalic modified resin made from tall oil fatty acids, available from Ranbar Technology, Inc. in Glenshaw, Pennsylvania.
  • the G-4495-100 resin has an isophthalic acid content of about 11% and an acid number of 8 mg KOH/g maximum.
  • the film-forming component can be used in any suitable amount.
  • the film-forming component will increase the viscosity of the ink undesirably, which in turn will adversely affect the image quality, for instance, the colorant strength may decrease and the ink drying time may increase.
  • the oil phase may advantageously contain one or more additives for improving the performance of the ink composition.
  • the oil phase may contain additives such as a rheological additive and an antiskinning agent.
  • the rheological additive is used to provide several advantages including high gelling efficiency, yield, and viscosity, to prevent pigment agglomeration and settling, and to allow better control of tack and viscosity.
  • the rheological additive also reduces ink misting, improves hiding, and reduces water pick up .
  • Any suitable rheological additive can be used.
  • suitable rheological additive include organically modified clays such as organically modified kaolinite, montmorillonite, illinite, attapulgite, allophane, and halloysite clays. Any suitable organically modified clay can be used.
  • Organically modified montmorillonite is a preferred organically modified clay.
  • Any suitable organically modified montmorillonite clay can be used.
  • the suitable organically modified montmorillonite clay preferably has a specific gravity of from about 1.5 to about 1.7 g/cc.
  • An example of a suitable organically modified montmorillonite clay is CLAYTONETM HY, available from Southern Clay Products, Inc. in Gonzales, Texas.
  • CLAYTONE HY is a finely divided powder having a specific gravity of 1.6 g/cc, a dry particle size of -450 mesh, a moisture content of 2% by weight, and a weight loss of 43% at 1000°C.
  • the organically modified clay plays several key roles in improving the performance of the ink.
  • the organically modified clay swells in the oil phase oil and holds the oil in place and thus prevents "bleed through” of the ink. It also prolongs the drying time of the wet printed image. This prolonged drying time allows sufficient time for the thermographic powder to be applied to the wet image, and for the subsequent passing of the image through the drying oven at 350°F where the image is permanently set.
  • the organically modified clay and the cellulose derivative present in the water phase work together to provide a stable gel structure to the ink composition of the present invention, which allows excellent printer runnability, environmental storage stability, and provides low ink "bleed through", and high color development and image density.
  • the organically modified clay also provides thixotropy, i.e., shear thinning property, to the ink composition.
  • the organically modified clay can be used in any suitable amount. It is advantageously used in an amount of from about 0.1% by weight to about 5% by weight of the ink, preferably in an amount of from about 1% by weight to about 3% by weight of the ink, and more preferably in an amount of from about 2% by weight to about 3% by weight of the ink. Excessive use of the organically modified clay may undesirably increase the viscosity and the drying time of the ink, which in turn can adversely affect the image quality such as rub resistance or smudge resistance.
  • the oil phase of the ink of the present invention may include an antiskinning agent.
  • the antiskinning agent is used to prevent premature film formation by accidental exposure of the ink to the atmosphere, which film would contaminate the ink.
  • the antiskinning agent works by complexing the active drier materials, thereby temporarily blocking the crosslinking until oven drying. Any suitable antiskinning agent can be used.
  • suitable antiskinning agents include oximes such as aldoximes and ketoximes. Oxime antiskinning agents are commercially available from Huls America, Inc. in Piscataway, New Jersey, as EXKINTM 1 and EXKIN 2.
  • EXKIN 1 is butyraldoxime
  • EXKIN 2 is methylethylketoxime.
  • EXKIN 2 is a preferred antiskinning
  • the antiskinning agent can be used in any suitable amount. It is advantageously used in an amount of from about 0.01% by weight to about 1% by weight of the ink, preferably in an amount of from about 0.1% by weight to about 0.3% by weight of the ink, and more preferably in an amount of from about 0.15% by weight to about 0.25% by weight of the ink.
  • the water phase of the ink composition may optionally comprise certain ingredients such as thickening agents, biocides, and humectants.
  • Deionized water is preferably used in the preparation of the water phase of the ink composition, to avoid salt build up in the equipment due to drying of the ink.
  • Water is used in an amount of from about 20% by weight to about 85% by weight, preferably in an amount of from about 25% by weight to about 80% by weight, and more preferably in an amount of from about 45% by weight to about 65% by weight of the ink of the present invention. Excessive use of the water may adversely affect the density of the image.
  • the water phase may preferably contain a suitable biocide to prevent growth of bacteria, mould or fungus in the ink.
  • a suitable biocide to prevent growth of bacteria, mould or fungus in the ink.
  • Methyl p-hydroxybenzoate (METHYL PARABEN) and 6-acetoxy-2,2- dimethyl-l,3-dioxane available as GIV GARD DXNTM from Givaudam Corp.
  • 2,6-dimethyl-m- dioxan-4-ol acetate available as bioban DXN from Angus Chemical Company
  • the biocide can be present in the ink of the present invention in an amount sufficient to prevent the attack by bacteria, mould, and fungus, which amount can be in the range of about 0.05% by weight to about 0.5% by weight, preferably in an amount of about 0.1% by weight of the ink.
  • the water phase may optionally contain a thickening agent.
  • the thickening agent provides enhanced stability to the ink composition by forming a gel structure in association with certain components of the oil phase such as the rheological additive.
  • the enhanced stability offers several advantages such as excellent printer runnability and long term storage stability. It also helps in obtaining high image density and color development of the printed image.
  • the thickening agent also provides freeze-thaw stability to the water phase and to the ink composition.
  • any suitable thickening agent can be used.
  • suitable thickening agents include cellulose derivatives such as hydroxyalkylcellulose and alkyl hydroxyalkylcellulose, wherein the alkyl group has 1-6 carbon atoms, and preferably 2 carbon atoms.
  • the hydroxyalkylcellulose and alkyl hydroxyalkylcellulose can have any suitable hydroxyalkyl content.
  • the hydroxyalkyl content is typically in the range of from about 1.5 to 2.6 moles per mole of the anhydroglucose unit, and preferably in the range of from about 1.9 to about 2.3 moles per mole of the anhydroglucose unit.
  • the "alkyl” hydroxylalkylcellulose derivative can have any suitable "alkyl” content.
  • the "alkyl” content of the alkyl hydroxylalkylcellulose derivative is typically in the range of from about 0.5 to about 1.0 mole per anhydroglucose unit, and preferably in the range of from about 0.7 to 0.9 mole per anhydroglucose unit. It is to be understood that the maximum content of alkyl and hydroxyalkyl together cannot exceed 3.0 moles per mole of anhydroglucose units.
  • HEC Hydroxyethylcellulose
  • EHEC ethyl hydroxyethylcellulose
  • HECs and EHECs suitable for use in the ink composition of the present invention typically have a Brookfield viscosity (Type LV) of from about 200 mPa.s to about 100,000 mPa.s, when measured as a 2% solution in water at 20°C, and preferably in the range of from about 4,000 mPa.s to about 80,000 mPa.s, when measured as a 2% solution in water at 20°C.
  • Type LV Brookfield viscosity
  • HEC Suitable examples include the CELLOSIZETM brand HECs available from H ⁇ ls America, Inc. in Piscataway, New Jersey. Thus, CELLOSIZE brand QP 4400, QP 15,000, QP 30,000, QP 52,000, and QP 100,000 are examples of commercially available HECs, with QP 30,000 being a preferred HEC.
  • EHEC Suitable examples include the BERMOCOLLTM E brand EHECs, available from Bero Nobel AB in Stennungsund, Sweden.
  • BERMOCOLL brand E230, E270, E320, E351, E411, E431, E451, and E481 are examples of suitable EHECs.
  • E230, E270, and E320 have an ethyl content of 0.8 mole per anhydroglucose unit and a hydroxyethyl content of 0.8 mole per anhydroglucose unit.
  • E230, E270, and E320 have a Brookfield viscosity (Type LV) of respectively, 300 ⁇ 60, 700+ 150, and 2,200 ⁇ 450 mPa.s, when measured as a 2% solution in water at 20°C, at spindle speeds, respectively of 1-12, 2-12, and 3-12.
  • E351, E411, E431, E451, and E481 have an ethyl content of 0.8 mole per anhydroglucose unit and a hydroxyethyl content of 2.1 mole per anhydroglucose unit.
  • E351 has a Brookfield viscosity (Type LV) of 5,000 ⁇ 1,000 when measured as a 2% solution in water at 20°C, at a spindle speed of 3-12.
  • E411, E431, E451, and E481 have a Brookfield viscosity (Type LV) of respectively, 1,000 ⁇ 200, when measured as a 1% solution in water at 20°C, at a spindle speed of 2-12, and 2,000 ⁇ 400, 3,000 ⁇ 600, and 5,000 ⁇ 1,000, when measured as a 1% solution in water at 20°C, at a spindle speed of 3-12.
  • Any suitable amount of the thickening agent can be used in the preparation of the ink. It is typically used in an amount of from about 0.5% by weight to about 3% by weight of the ink, and preferably in an amount of from about 1% by weight to about 3% by weight of the ink. Excessive use of the thickening agent will have adverse consequences such as instability of the ink.
  • the water phase of the present inventive ink may preferably comprise a humectant which prevents the loss of water from the ink by evaporation.
  • the humectant may also serve as an antifreeze agent. Any suitable humectant known to those of ordinary skill in the art can be used.
  • humectant component use can be made of aliphatic polyols, and preferably glycerin and alkylene glycols in which the alkylene group preferably contains 2-6 carbon atoms, as represented by ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, and the polyalkylene glycols as represented by diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, and tetraethylene glycol. It is also possible to employ as humectant commercially available polyalkylene glycols such as Carbowax 200 or Carbowax 400, which are polyethylene glycols having average molecular weights of bout 200 and 400, respectively.
  • humectant polyalkylene glycols such as Carbowax 200 or Carbowax 400, which are polyethylene glycols having average molecular weights of bout 200 and 400, respectively.
  • polyalkylene glycols In general, it is preferred, when using polyalkylene glycols, to use those materials having an average molecular weight less than 600 since higher molecular weight polyalkylene glycols frequently serve to undesirably increase the viscosity of the ink composition.
  • any suitable amount of the humectant can be used in the preparation of the ink. It is typically used in an amount of from about 1% by weight to about 10% by weight of the ink, and preferably in an amount of from about 2% by weight to 7% by weight of the ink. Excessive use of the humectant will increase the viscosity of the ink undesirably.
  • the ink composition of the present invention can have any suitable proportions of the oil and water phases.
  • the ink composition typically contains the oil phase in a proportion of from about
  • Example 1 This example illustrates the preparation of an encapsulated colorant.
  • the encapsulated colorant was prepared as follows. TUFFLO 2000, RESINALL 514, and LX 2000 were combined in a HIDROBAT-10 mixer, and stirred for one hour at 160°C when the resins completely dissolved. The temperature was then reduced to 130°C and AC 656 was added and mixed for about 20 minutes. PRIMEX SSF was then added and mixed for about 10 minutes. The temperature was then reduced to 110°C, the mineral seal oil was added and mixed, and MONARCH 120 was added slowly over a period of about 10 to about 20 minutes. The mixing was continued for about 1 hour after the addition of carbon black to obtain the encapsulated colorant. Examples 2-8
  • the ink of the example 2 had a plastic viscosity of 13,355 cP (or mPa-s) and a yield stress of 3,608 dynes/cm 2 (or N/m 2 ), with a Confidence of Fit of 98.3%.
  • the ink also had a consistency index of 235,965 cP (or mPa-s) and a flow index of 0.33 with a Confidence of Fit of 98.6%.
  • the amount of ink used for the measurement was 2.2 gm and the measurements were done at a temperature of 20°C.
  • the Filtrez 681 resin was pre-dissolved in hot (170°C) Agrisolv H oil, the ingredients of the oil phase were combined and blended in a suitable mixer, blended and passed through a three-roll mill. The milled materials were then mixed in a suitable mixer or blender. The pre-prepared water phase was then added slowly to form a water-in-oil emulsion ink. The mixing was continued until a uniform smooth emulsion ink was obtained.
  • Example 5 The Oil Phase
  • the oil phase was prepared as following. Tufflo Process Naphthenic oil 2000 oil, Agrisolv H oil, Resinall 514, and Filtrez 681 were combined in a suitable mixer and stirred at 170°C until the resins were completely dissolved. The temperature was then reduced to 110°C, the Primex SSF was then added and mixed for about 10 minutes, and Monarch 120 was added slowly with mixing. The mixing was continued for about two hours after the addition of carbon black, and then passed through a three-roll mill. The milled materials were then mixed with sorbitan monooleate, Actiflo 68 UB, Extac 52, and mineral seal oil in a suitable mixer or blender. The pre-prepared water phase was added slowly with mixing to form a water-in-oil emulsion ink. The mixing was continued until a uniform smooth emulsion ink was obtained.
  • the oil phase was prepared as following. Varnish C-135, Tufflo Process Naphthenic oil
  • the oil phase was prepared as following. Resin Filtrez 681 was dissolved in the mixture oils of Sunpar 150 oil and Agrisolv H oil at about 170°C to obtain a varnish. This varnish was then mixed well with Converse SW-6500 black base in a suitable mixer, and were then passed through a three-roll mill. The milled materials were then mixed with sorbitan monooleate, Actiflo 68 UB, Extac 52, and mineral seal oil in a suitable mixer or blender to obtain the oil phase. The water-in-oil emulsion was prepared following the procedure set forth in examples 2-4. In each example, the ink had suitable physical properties and was tested on the commercially available RISOGRAPH® GR 1700 Digital Duplicator. Good printed imaging density, imaging rub resistance, and ink dry time, ink show-through, ink stability, and set-off free were obtained.

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Abstract

The present invention provides a water-in-oil emulsion ink comprising an oil phase and a water phase, the oil phase comprising a colorant or an encapsulated colorant, said ink having high gel structures, making them especially suited for use in Risograph type digital duplicators.

Description

A WATER-IN-OIL EMULSION DIGITAL DUPLICATING INK
The present invention relates to water-in-oil emulsion duplicating inks used in digital
duplicators. Emulsion inks are generally used in digital duplicating processes. In those processes, the ink is introduced into a cylinder having a plurality of small holes. The circumferential wall of the cylinder is formed with such holes, and a stencil is wrapped around the cylinder. During the printing process, the ink penetrates through the holes in the cylinder and the selectively formed image openings in the stencil onto the surface of a paper. The paper is held in contact with the cylinder and stencil by means of a platen roller.
Emulsion inks are formulated with an oil phase and an aqueous phase. The oil phase generally contains drying oils. The colorant is dispersed either in the oil phase or in the water phase.
Several ink formulations having carbon black colorant dispersed in the aqueous phase are disclosed in U.S. Patents 2,839,412, 3,421,910, and 3,823,020. U.S. Patent 5,378,739 discloses an ink formulation having carbon black dispersed in the oil phase.
The fibers of the paper have numerous small pores, which act to break down the two phases in the ink as the ink is absorbed into the paper. The water in the aqueous phase diffuses through the paper leaving behind the carbon black on the surface. The drying oils of the oil phase dry and form a film on the carbon black and immobilize the carbon black on the paper to produce a permanent image.
Certain problems have been experienced in using ink formulations having the colorant dispersed in the aqueous phase, particularly the "bleed through" problem. The water from the water phase that diffuses through the pores of the paper carries the colorant along with it. This "bleed through" results in the colorant being deposited on the back side of the paper. The colorant deposited on the back side becomes visible and the quality of the printed image thus becomes poor. In U.S. Patent No. 5,622,548, there is disclosed a water-in-oil emulsion ink comprising an oil phase and a water phase, the oil phase comprising an encapsulated colorant, an oil phase oil, a surface active agent, and a film-forming component, and the water phase comprising water. The encapsulated colorant comprises a colorant, at least one binder resin, a saturated oil, a viscosity adjusting agent, and an adhesion promoter.
Although the ink of US-5,622,548 is well suited for its intended purpose, it has certain drawbacks when used in certain specific applications. For example, the ink of US-5,622,548 is not particularly well suited for use in a Risograph digital duplicator. The inks of US-5,622,548 do not exhibit any significant gel structure, typically having a yield stress of about 950- 1 ,200 dynes/cm2 and a consistency index of about 60,000-82,000. When such inks -ire used in a Risograph digital duplicator, the ink tends to leak out from the tail of the stencil. The low ink gel structure also causes the Risograph duplicator to lay down too much ink onto the paper, causing setoff, showthrough, rub off, slow dry time, and low printing yield. A particular goal of the present invention was to provide an ink that would exhibit good emulsion stability and ink shelf life, and provide printed images with good rub resistance and image quality when used in a Risograph digital duplicator.
According to the present invention there is provided a water-in-oil emulsion ink for use in digital duplicators comprising an oil phase and a water phase, the oil phase comprising a colorant and optionally a film-forming component, and the water phase comprising water. In particular, the ink of the present invention comprises one or more additional components selected from the group consisting of (1) phenolic modified esters of rosin, (2) gelled oils, (3) co-emulsifiers, and (4) a non- drying oil or a combination comprising a non-drying vegetable oil and petroleum distillate.
The ink formulations of the present invention exhibit higher yield stress (ink gel structure), a higher plastic viscosity, a higher consistency index and a lower flow index than the ink of US-5,622,548. In particular, the inks of the present invention exhibit a yield stress of about 2,000 to about 8,000 dynes/cm2, a consistency index of about 100,000 to about 500,000 and a flow index of about 0.20 to about 0.40. Typically, the plastic viscosity will be from about 6,000 to about 20,000
cp (or mPas).
The present invention also provides an improved digital duplicating process for producing images having high color strength, high image density, good image resolution, low set-off, low "bleed through", excellent runnability, and better environmental stability, wherein the improvement comprises using an ink comprising an oil phase and a water phase, the oil phase comprising a colorant and optionally a film-forming component, and the water phase comprising water. In particular, the ink of the present invention comprises one or more additional components selected from the group consisting of (1) phenolic modified esters of rosin, (2) gelled oils, (3) co-emulsifiers, and (4) non-drying oils or combinations comprising a non-drying vegetable oil and petroleum distillate. Preferred embodiments of the present invention will now be described.
The present invention provides water-in-oil emulsion ink formulations suitable for use in digital duplicators that offer high color strength, high image density, good image resolution, low set- off, low "bleed through", excellent runnability, and good environmental stability.
The water-in-oil emulsion ink formulation of the present invention comprises an oil phase and a water phase, the oil phase comprising a colorant, which may be an encapsulated colorant, and the water phase comprising water.
The water-in-oil ink emulsions of the present invention exhibit physical characteristics that make them more suited to use in a Risograph digital duplicator. These improved physical characteristics are achieved by use of one or more of the following components: (1) phenolic modified esters of rosin, (2) gelled oils, (3) co-emulsifiers, and (4) a non-drying oil or a combination comprising a non-drying oil and petroleum distillate.
In one aspect of the present invention, the gel structure of the present water-in-oil emulsion ink is achieved through the use of gelling and/or thickening agents in the oil phase; preferably there is sufficient gelling and/or thickening agent in the oil phase to result in an ink having a yield stress of about 2,000 to about 8,000 dynes/cm2 and a consistency index of about 100,000 to about 500,000.
In a preferred aspect of the present invention the water phase is substantially free of gelling and thickening agents. In such an embodiment the gel structure of the water-in-oil emulsion results from the components in the oil phase as opposed to components of the water phase. Although the goals of the present invention are best achieved by use of an encapsulated colorant, the benefit of the present invention may also be achieved through use of a colorant alone or dispersed pigment.
PHENOLIC MODIFIED ESTERS OF ROSIN Any phenolic modified ester of rosin can be used. Examples of suitable phenolic modified esters of rosin include Filtrez 625N, Filtrez 623, Filtrez 686, Filtrez 681, and Filtrez 657, available from AKZO NOBEL Resin and Vehicle, Matteson, IL., and Ultra-Rez™ 135, Ultra-Rez™ 150,
Ultra-Rez 165, and Ultra-Rez 175, available from Lawter International, Inc., Northbrook, IL.
Filtrez 681, which has a softening point of 160°C to 170°C, is preferred. Filtrez 681 is a phenolic modified rosin pentaerythritol ester.
The phenolic modified ester of rosin improves the ink setting time, the drying time, setoff, showthrough, rub resistance and high speed printing performance. The phenolic modified ester of rosin is usually present in an amount from about 0 to about 8 percent, based on the total weight of the ink emulsion. Preferably, the phenolic modified ester of rosin will be present in an amount of about 2 to about 5 percent.
GELLED OILS
Any gelled oil can be used. Examples of a suitable gelled oil include gelled petroleum oil, gelled hydrotreated petroleum oil, gelled paraffinic oil, gelled naphthenic oil, gelled paraffinic process oil, gelled naphthenic process oil, and gelled vegetable oil. Gelled technical grade white oil such as Extac 52, Extac 47 or Extac 60 are preferred. The gelled oil helps to build the gel structure of the ink and is usually present in an amount from about 0 to about 15 percent, based on the total weight of the ink. Preferably, the gelled oil will be present in an amount of about 2 to about 8 percent.
CO-SURFACE ACTIVE AGENT
Any emulsifiers can be used as a co-surface active agent to improve the ink stability and shelf life. One such suitable co-surface active agent is lecithin. Any grade and supplier of lecithin may be used. Actiflo 68UB, which has an acid value of 23, and Centrol 2FUB, which has an acid value of 28, are preferred. The lecithin improves the ink stability and shelf life and is usually present in an amount from about 0 to about 8 percent, based on the total weight of the ink. Preferably, the co-surface active agent will be present in an amount of about 1 to about 5 percent.
NON-DRYING OIL OR NON-DRYING OIL COMBINATION
Any non-drying oils or non-drying oil combination can be used. Examples of suitable non- drying oils include petroleum distillate, hydrotreated petroleum oil, paraffinic oil, naphthenic oil, paraffinic process oil, naphthenic process oil, technical grade white oil, and non-drying vegetable oil. One or a combination of oils can be employed. The vegetable oil is preferably Agrisolv H, and the petroleum distillate is preferably selected from the Sunpar series, mineral seal oil or Isopar series, such as Sunpar 115, Sunpar 120, Sunpar 130, Sunmpar 150, and Isopar L. The non-drying oils or a combination of oils improves open time, dry time for the ink and assists in optimizing ink rheology. The oils may be used in various ratios, and are usually present in an amount from about 0 to about 60 percent, based on the total weight of the ink. Preferably, the non-drying oil or non- drying oil combination will be present in an amount of about 5 to about 35 percent.
COLORANTS
Any colorant can be used. The colorant may be a dye or a pigment. The colorant may be organic or inorganic. Examples of suitable colorants, which optionally may be encapsulated and used in accordance with the present invention include C.I. Blue 15:3, available as Process Blue Pigment 249-2083 from Sun Chemical Corp., and the C.I. Green 7, available as Green Pigment 264- 8142 from Sun Chemical Corp., C.I. Violet 1, which is a Rhodamine B PTMA type pigment and available from Magruder Color Company in Elizabeth, New Jersey, as MM 0107-DC, and carbon black. The types of carbon black include Channel black, furnace black, and lamp black. Any suitable carbon black can be used in the preparation of the ink and the encapsulated colorant of the present invention. Preferably, the carbon black has a BET surface area of from about 20 square meters per gram to about 600 square meters per gram, and a dibutylphthalate (DBP) oil absorption of from about 20 cc/100 gm to about 200 cc/100 gm. MONARCH™ 120, MONARCH 280, REGAL™ 250R, and REGAL 350R from Cabot Corporation are examples of preferred carbon black colorants. MONARCH 120 is a lamp type carbon black having a particle size of 0.075 microns, a BET surface area of 25 square meters per gm, and a DBP oil absorption of 64 cc/100 gm. MONARCH 280 is a lamp type carbon black having a particle size of 0.045 microns, a BET surface area of 42 square meters per gm, and a DBP oil absorption of 121 cc/100 gm. REGAL 250R has a particle size of 0.035 microns, a BET surface area of 50 square meters per gm, and a DBP oil absorption of 46 cc/100 gm. REGAL 35 OR is a blue-toned carbon black. More examples of preferred carbon black colorants include Printex 300, Printex 25, and special black 250 from Degussa Corporation.
Examples of suitable colorants also include commercial available pigment dispersions (Flush), such as sheet-fed black base SFK-135, SFK-218, SW-6100, SW-6300, SW-6500, SW-6800, and RFK-236 quality forms black base available from Continental Dispersions, Inc., West Chicago, Illinois, Q.S. Black #7187, Q.S. Black QB-6807S, and Q.S. Black QB-6824 available from ACRO, Inc., Fennville, Michigan, and 40 Plus Base Black and 40 Plus "EZ" Base Black available from Kerly Ink, Broadview, Illinois. More examples of suitable colorants also include aforedescribed colorant alone. These colorants can be directly used in the oil phase to prepare the water-in-oil
emulsion ink.
Examples of other suitable colorants include metallized azo reds such as Red 49:1 (barium salt), Red 49:2 (calcium salt), Red 63:1 (calcium salt), toluidine reds, naphthol reds, pyrazalones, rhodamines, quinacridones such as Red B, Red Y, Magenta B, Magenta and Violet, phthalocyanine blues, phthalocyanine greens, carbazole yellow, monoarylide yellow, diarylide yellow, chrome yellow, red lake C, lithol reds such as calcium and barium salts, lithol rubine, bon maroon, perylene pigments, Red 2B pigments including the calcium, barium and magnesium salts, chrome yellow, chrome orange, molybdate orange, lead chromes, lead silicochromates, zinc chromes, barium chromate, strontium chromate, titanium nickel yellow, liminites, haematite, magnetite, micaceous oxides of iron, siderite, iron pyrites, ferrite yellow, red oxide, prussian blue, Orange 36, diarylide orange, dianisidine orange, tolyl orange, and dinitraniline orange.
Any suitable amount of the aforedescribed colorant can be used in the preparation of the ink.
It is typically used in an amount of from about 3% by weight to about 35% by weight of the ink, and preferably in an amount of from about 4% by weight to about 20% by weight of the ink. Excessive use of the colorant will adversely affect the image quality, for instance, the image resolution will decrease and image set-off will increase.
ENCAPSULATED COLORANT The encapsulated colorant preferably comprises a colorant having a particle size of from about 0.01 microns to about 25 microns, preferably having a particle size of from about 0.01 microns to about 5 microns, an adhesion promoter, and at least one binder resin usually selected from the group consisting of a hydrocarbon modified rosin ester and a phenol modified hydrocarbon resin.
The encapsulated colorant can be prepared by any suitable method. It is preferably prepared in accordance with the method of U.S. Patent No. 5,622,548. In accordance with that method a suitable colorant is combined with an oil component, a binder resin component, and preferably an adhesion promoter and a disperser vehicle. The components of the encapsulated colorant are combined sequentially and mixed in a suitable mixer or blender until a uniformly mixed encapsulated colorant is produced. A detailed discussion of the various components of the encapsulated colorant is set forth in U.S. Patent No. 5,622,548.
The oil phase comprises one or more oils. Any suitable oil, including saturated and unsaturated, can be used. The oil may be used to prepare the encapsulated colorants or optionally may be directly used in the oil phase of the ink when the dispersed colorant or colorant alone are used. The saturated oil preferably has a boiling point of from about 280°C to about 420°C and a viscosity of from about 300 Saybolt Universal Standard (SUS) to about 2400 SUS at 100°F. Examples of suitable saturated oils include aromatic, naphthenic, and paraffinic oils. Examples of suitable aromatic oils include FLEXON™ 340 and FLEXON on 391, SUNDEX™ 790 and SUNDEX 8600T, and TUFFLO™ 491. Examples of naphthenic oils include CIRCOSOL™ 450, CIRCOSOL 4240, CIRCOSOL 5600, SUNTHANE™ 450, SUNTHANE 4240, FLEXON 676, FLEXON 766, TUFFLO 500, TUFFLO 750, TUFFLO 2000, TUFFLO 6024, and examples of paraffinic hydrocarbon include SUNPAR 150, SUNPAR 2280, FLEXON 815, FLEXON 865, TUFFLO 60 and TUFFLO 80. A preferred oil is TUFFLO 2000, which has a viscosity of 2117 SUS at 100°F, boiling point of 320°C, an acid number of 0.05 mg KOH/g, and a color index of 2.5. TUFFLO brand oils are available from EMCO Chemical Distributors, Inc. in Northbrook, 111., CIRCOSOL, SUNTHANE, SUNPAR, and SUNDEX brand oils are available from Sun Oil Co., in
Amelia, Ohio.
Examples of suitable unsaturated oils include ground nut, cashew nut, castor, chia, corn (maize), cotton seed, hemp, linseed, lumbang, niger seed, oiticia, perilla, poppy, po-yok, safflower, soya, stillingia, sunflower, tobacco seed, tung, and walnut oils, and combination thereof, with the soybean oil and linseed oil being examples of preferred oils.
The oil may be used in any suitable amount. It is typically used in an amount of from about 10% by weight to about 60% by weight of the encapsulated colorant, and preferably in an amount of from about 20% by weight to about 45% by weight of the encapsulated colorant. Excessive use of the oil will increase drying times undesirably.
The oil component may also include one or more of viscosity adjusting agents such as low viscosity aliphatic oils, naphthenic oils, and tall oil fatty esters. The viscosity adjusting agents preferably have a viscosity of from about 3.0 CST @ 104°F (or 36 SUS @ 100°F) to about 4.0 CST @ 104°F (or 39 SUS @ 100°F), and more preferably a viscosity of from about 3.4 to about 3.6 CST @ 104°F. Mineral seal oil, a preferred viscosity adjusting agent and available from EMCO Chemical Distributors, Inc., is an aliphatic oil having a boiling point of 250°C, an acid number of 0.01 mg KOH/g, and a viscosity of 3.53 CST @ 104°F.
If a zero-VOC ink formulation is desired, higher boiling viscosity adjusting agents may be utilized. For instance, tall oil fatty acid esters such as CrC8 alkyl and mono-, di- and trialkylene glycol esters of tall oil fatty acids, can be used as the viscosity adjusting agents. Several tall oil fatty acid esters are commercially available. For example, NIREZ™ brand tall oil fatty acid esters are available from Arizona Chemical Company Co. in Panama City, Fla. Suitable NIREZ brand tall oil esters include NIREZ 9011, which is a methyl ester of tall oil fatty acid and has a Brookfield viscosity of 7 centipoises (cps), an acid number of 5 mg KOH/g, an iodine value of 105 minutes (Wijs), and a EPA-24 volatiles content of 8% NIREZ 9012, which is a butyl ester of tall oil fatty acid and has a Brookfield viscosity of 7 cps, an acid number of 2 mg KOH/g, an iodine value of 110 minutes, and a EPA-24 volatiles content of 2%, NIREZ 9015, which is a butyl ester of tall oil fatty acid and has a Brookfield viscosity of 8 cps, an acid number of 14 mg KOH/g, an iodine value of 112 minutes, and a EPA-24 volatiles content of 2%, NIREZ 9007, which is a 2-ethylhexyl ester of tall oil fatty acid and has a Brookfield viscosity of 14 cps, an acid number of less than 1 mg KOH/g, an iodine value of 97 minutes, and a EPA-24 volatiles content of less than 1% NIREZ 9017, which is a diethylene glycol ester of tall oil fatty acid and has a Brookfield viscosity of 37 cps, an acid number of 8 mg KOH/g, an iodine value of 110 minutes, and a EPA-24 volatiles content of less than 1 %, NIREZ 9014, which is a methyl ester of tall oil fatty acid and has a Brookfield viscosity of 15 cps, an acid number of 5 mg KOH/g, an iodine value of 73 minutes, and a EPA-24 volatiles content of 8%. NIREZ 9012 is a preferred tall oil fatty acid ester.
The viscosity adjusting agent may be used in any suitable amount in the preparation of the encapsulated colorant. When used, the viscosity adjusting agent is generally used in an amount of from above 0% by weight to about 25% by weight, and preferably in an amount of from about 8% by weight to about 12% by weight of the encapsulated colorant. Excessive use of the viscosity adjusting agent will result in too low of a viscosity and a yield value of the ink that produces a poor image resolution and poor runnability. SURFACE ACTIVE AGENT
The oil phase may preferably include a suitable surface active agent to facilitate and stabilize the emulsion. The surface active agent may also reduce the surface tension energy of the oil phase, thereby increasing the drying rate of the ink. Any suitable surface active agent may be used, including anionic, cationic, nonionic, amphoteric surface active agents, and combinations thereof. Nonionic surface active agents are preferred. Examples of suitable nonionic surface active agents include fatty acid esters of sorbitan such as sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan sesquioleate, sorbitan trioleate, sorbitan monoolaurate, sorbitan dilaurate, sorbitan trilaurate, and fatty acid triglycerides such as oleic acid monoglyceride, oleic acid diglyceride, polyethylene oxide adducts of fatty acids such as polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, and ethylene oxide adducts of alkyl phenols and higher alcohols. Several of the surface active agents are available from common chemicals suppliers, including Aldrich Chemical Co. in Milwaukee, Wisconsin. Sorbitan monooleate, a preferred surface active agent, is also available from EMCO Chemical Distributors, Inc.
The surface active agent can be used in any suitable amount. It is typically used in the oil phase in an amount of from about 0.5% by weight to about 8% by weight of the ink, and preferably in an amount of from about 1% by weight to about 3% by weight of the ink. Excessive use of the surface active agent is to be avoided because the excess surface active agent will diffuse through the paper and make it transparent, and destabilize the emulsion.
FILM-FORMING COMPONENT
The oil phase preferably comprises a film-forming component. The film-forming component rapidly forms a tough and durable film on the colorant particle, immobilizes the colorant on the paper, and helps produce images of high color strength and good image resolution. Any suitable film-forming component compatible with the oil phase oils may be used as the film-forming component. Examples of suitable film-forming components are hydrocarbon resins such as polyolefin resins and terpene resins, polyester resins such as alkyd resins, and unsaturated polyester resins such as the resins prepared from the condensation polymerization of a glycol such as 1 :2- propylene glycol or 1 :3-butylene glycol with an unsaturated acid such as maleic acid.
Any suitable terpene resin can be used. Suitable terpene resins include those having a number average molecular weight (Mn) of from about 500 to 5,000, and preferably those having an Mn of from about 600 to about 1000. It is further preferred that the terpene resin has a melting point or softening point of from about 80°C to about 150°C, and it is further preferred that the terpene resin has a melting point or softening point of from about 100°C to about 140°C. Examples of suitable terpene resins include PICCOL YTE™ 115 and PICCOL YTE 135, which are available from Hercules, Inc. in Wilmington, Delaware. PICCOL YTE 115 has a softening point of 115°C (Ring and Ball or R&B), a glass transition temperature of 59°C (onset), a Mn of 625, a Mw/Mn of 1.8, and an acid number of 0.0 mg KOH/g. PICCOLYTE 135 has an R&B softening point of 131 °C, a glass transition temperature of 81°C (onset), a Mn of 750, and a Mw/Mn of 1.6.
Alkyd resins are fatty acid esters of drying oils such as the unsaturated oils obtained from ground nut, cashew nut, castor, chia, com (maize), cotton seed, hemp, linseed, lumbang, niger seed, oiticia, perilla, poppy, po-yok, safflower, soya, stillingia, sunflower, tobacco seed, tung, and walnut. It is known to those of ordinary skill in the art that unsaturated fatty acids present in the aforesaid drying oils include linolenic acid, linoleic acid, oleic acid, and ricinoleic acid.
The alkyd resins can be prepared by any method known to those of ordinary skill in the art including, for example, by esterification or ester interchange reaction of a mixture of the fatty acid, a polybasic acid, and a polyhydric alcohol. Examples of suitable polybasic acids include the compounds having 2 to 4 carboxyl groups or methyl carboxylate groups per molecule such as phthalic acid or anhydride, isophthalic acid, terephthalic acid, maleic acid or anhydride, fumaric acid or anhydride, pyromellitic acid or anhydride, trimellitic acid or anhydride, benzene tetracarboxylic dianhydride, succinic acid or anhydride, sebacic acid, azelaic acid, dodecanedicarboxylic acid, dimethyl isophthalate, dimethyl terephthalate, and the like, and combinations thereof. Examples of suitable polyhydric alcohols include ethylene glycol, propylene glycol, propane triol, glycerol, neopentyl glycol, 1 ,6-hexanediol, trimethylolpropane, sorbitol, tricyclodecanedimethanol, and
pentaerythritol.
By way of illustration, suitable amounts of phthalic anhydride and glycerol are heated to 180°C to the "first stage" syrup having residual or free hydroxyl groups, and molten fatty acids are added to esterify the free hydroxyl groups. Heating is continued at 180°C to 220°C until the desired acid number and solubility characteristics are reached.
In an alternative method, the three raw materials, phthalic anhydride, glycerol, and fatty acid are placed in a reaction vessel together with a small quantity of xylol. The vessel is fitted with a condenser to which is attached a water separator of the Dean Stark type. On heating, the water produced is carried off with the xylol and is separated. The condensing xylol serves to flush the sublimed phthalic anhydride back into the reaction vessel. The amount of water collected is an indication of the progress of esterification, but samples of the resin are removed from time to time and for acid number and viscosity checks. The reaction vessels are generally of stainless steel fitted with stirrer, charge hole, condensing system, and pipes for passing inert gas over the charge. The latter serves to reduce discoloration. Heating can be provided by any known means including by immersion heaters, and by passing hot fluids such as hot liquid or gas through a jacket surrounding the vessel. An example of a hot liquid is a hot oil. The necessity of isolating the fatty acids can be avoided in the preparation of glycerol type resins by the use of monoglycerides which are then further esterified with phthalic anhydride. The monoglycerides are formed by heating the drying oil with the necessary amount of glycerol to about 250°C to about 280°C when the fatty acid triglyceride undergoes alcoholysis to form the monoglyceride. The phthalic anhydride is added and the reaction completed at about 180°C to about
250°C.
A preferred alkyd resin is a modified tall oil fatty acid ester that is capable of forming a fast- forming film on the encapsulated colorant during the duplicating process and provides a film that is tough and durable. Tall oil fatty acid is essentially linoleic acid, and is derived from wood-pulp. It is preferred that the tall oil is virtually free of rosin acids so that the tall oil fatty acid can be used to produce a resin which is non-yellowing and exhibits excellent gloss. It is further preferred that the modification comprises an aromatic polycarboxylic acid. It is believed that the aromatic moiety imparts toughness and durability to the film. Examples of suitable aromatic polycarboxylic acids include aromatic compounds having 2 to 4 carboxyl groups in the free acid, anhydride, or lower alkyl ester form per molecule, such as phthalic acid, phthalic anhydride, or alkyl phthalate ester, isophthalic acid, terephthalic acid, pyromellitic acid or anhydride, trimellitic acid or anhydride, and benzene tetracarboxylic dianhydride. An example of a preferred aromatic polycarboxylic acid is isophthalic acid. The aromatic polycarboxylic acid content of the modified alkyd resin is preferably in an amount of from about 1% by weight to about 20% by weight of the alkyd resin, and is more preferably in an amount of from about 5% by weight to about 15% by weight, and most preferably in an amount of from about 9% by weight to about 12% by weight of the alkyd resin. An example of a preferred alkyd resin is G-4495-100™, an isophthalic modified resin made from tall oil fatty acids, available from Ranbar Technology, Inc. in Glenshaw, Pennsylvania. The G-4495-100 resin has an isophthalic acid content of about 11% and an acid number of 8 mg KOH/g maximum. The film-forming component can be used in any suitable amount. It is typically used in an amount of from about 2% by weight to about 16% by weight of the ink, preferably in an amount of from about 3% by weight to about 10% by weight of the ink, and more preferably in an amount of from about 4% by weight to about 8% by weight of the ink. Excessive use of the film-forming component will increase the viscosity of the ink undesirably, which in turn will adversely affect the image quality, for instance, the colorant strength may decrease and the ink drying time may increase.
OTHER ADDITIVES
In addition to the various components discussed above, the oil phase may advantageously contain one or more additives for improving the performance of the ink composition. Thus, the oil phase may contain additives such as a rheological additive and an antiskinning agent.
The rheological additive is used to provide several advantages including high gelling efficiency, yield, and viscosity, to prevent pigment agglomeration and settling, and to allow better control of tack and viscosity. The rheological additive also reduces ink misting, improves hiding, and reduces water pick up .
Any suitable rheological additive can be used. Examples of suitable rheological additive include organically modified clays such as organically modified kaolinite, montmorillonite, illinite, attapulgite, allophane, and halloysite clays. Any suitable organically modified clay can be used. Organically modified montmorillonite is a preferred organically modified clay. Any suitable organically modified montmorillonite clay can be used. The suitable organically modified montmorillonite clay preferably has a specific gravity of from about 1.5 to about 1.7 g/cc. An example of a suitable organically modified montmorillonite clay is CLAYTONE™ HY, available from Southern Clay Products, Inc. in Gonzales, Texas. CLAYTONE HY is a finely divided powder having a specific gravity of 1.6 g/cc, a dry particle size of -450 mesh, a moisture content of 2% by weight, and a weight loss of 43% at 1000°C.
The organically modified clay plays several key roles in improving the performance of the ink. Thus, the organically modified clay swells in the oil phase oil and holds the oil in place and thus prevents "bleed through" of the ink. It also prolongs the drying time of the wet printed image. This prolonged drying time allows sufficient time for the thermographic powder to be applied to the wet image, and for the subsequent passing of the image through the drying oven at 350°F where the image is permanently set. Further, the organically modified clay and the cellulose derivative present in the water phase work together to provide a stable gel structure to the ink composition of the present invention, which allows excellent printer runnability, environmental storage stability, and provides low ink "bleed through", and high color development and image density. In addition, the organically modified clay also provides thixotropy, i.e., shear thinning property, to the ink composition.
The organically modified clay can be used in any suitable amount. It is advantageously used in an amount of from about 0.1% by weight to about 5% by weight of the ink, preferably in an amount of from about 1% by weight to about 3% by weight of the ink, and more preferably in an amount of from about 2% by weight to about 3% by weight of the ink. Excessive use of the organically modified clay may undesirably increase the viscosity and the drying time of the ink, which in turn can adversely affect the image quality such as rub resistance or smudge resistance.
The oil phase of the ink of the present invention may include an antiskinning agent. The antiskinning agent is used to prevent premature film formation by accidental exposure of the ink to the atmosphere, which film would contaminate the ink. The antiskinning agent works by complexing the active drier materials, thereby temporarily blocking the crosslinking until oven drying. Any suitable antiskinning agent can be used. Examples of suitable antiskinning agents include oximes such as aldoximes and ketoximes. Oxime antiskinning agents are commercially available from Huls America, Inc. in Piscataway, New Jersey, as EXKIN™ 1 and EXKIN 2. EXKIN 1 is butyraldoxime and EXKIN 2 is methylethylketoxime. EXKIN 2 is a preferred antiskinning
agent.
The antiskinning agent can be used in any suitable amount. It is advantageously used in an amount of from about 0.01% by weight to about 1% by weight of the ink, preferably in an amount of from about 0.1% by weight to about 0.3% by weight of the ink, and more preferably in an amount of from about 0.15% by weight to about 0.25% by weight of the ink.
THE WATER PHASE The water phase of the ink composition may optionally comprise certain ingredients such as thickening agents, biocides, and humectants.
WATER
Deionized water is preferably used in the preparation of the water phase of the ink composition, to avoid salt build up in the equipment due to drying of the ink. Water is used in an amount of from about 20% by weight to about 85% by weight, preferably in an amount of from about 25% by weight to about 80% by weight, and more preferably in an amount of from about 45% by weight to about 65% by weight of the ink of the present invention. Excessive use of the water may adversely affect the density of the image.
BIOCIDE
The water phase may preferably contain a suitable biocide to prevent growth of bacteria, mould or fungus in the ink. Methyl p-hydroxybenzoate (METHYL PARABEN) and 6-acetoxy-2,2- dimethyl-l,3-dioxane (available as GIV GARD DXN™ from Givaudam Corp.) and 2,6-dimethyl-m- dioxan-4-ol acetate (available as bioban DXN from Angus Chemical Company) are suitable biocides, with the latter being a preferred biocide. The biocide can be present in the ink of the present invention in an amount sufficient to prevent the attack by bacteria, mould, and fungus, which amount can be in the range of about 0.05% by weight to about 0.5% by weight, preferably in an amount of about 0.1% by weight of the ink.
THICKENING AGENT
The water phase may optionally contain a thickening agent. The thickening agent provides enhanced stability to the ink composition by forming a gel structure in association with certain components of the oil phase such as the rheological additive. The enhanced stability offers several advantages such as excellent printer runnability and long term storage stability. It also helps in obtaining high image density and color development of the printed image. In addition, the thickening agent also provides freeze-thaw stability to the water phase and to the ink composition.
Any suitable thickening agent can be used. Examples of suitable thickening agents include cellulose derivatives such as hydroxyalkylcellulose and alkyl hydroxyalkylcellulose, wherein the alkyl group has 1-6 carbon atoms, and preferably 2 carbon atoms.
The hydroxyalkylcellulose and alkyl hydroxyalkylcellulose can have any suitable hydroxyalkyl content. The hydroxyalkyl content is typically in the range of from about 1.5 to 2.6 moles per mole of the anhydroglucose unit, and preferably in the range of from about 1.9 to about 2.3 moles per mole of the anhydroglucose unit.
The "alkyl" hydroxylalkylcellulose derivative can have any suitable "alkyl" content. The "alkyl" content of the alkyl hydroxylalkylcellulose derivative is typically in the range of from about 0.5 to about 1.0 mole per anhydroglucose unit, and preferably in the range of from about 0.7 to 0.9 mole per anhydroglucose unit. It is to be understood that the maximum content of alkyl and hydroxyalkyl together cannot exceed 3.0 moles per mole of anhydroglucose units.
Hydroxyethylcellulose (HEC) and ethyl hydroxyethylcellulose (EHEC) are preferred
examples of cellulose derivatives. Any suitable HEC or EHEC can be used. HECs and EHECs suitable for use in the ink composition of the present invention typically have a Brookfield viscosity (Type LV) of from about 200 mPa.s to about 100,000 mPa.s, when measured as a 2% solution in water at 20°C, and preferably in the range of from about 4,000 mPa.s to about 80,000 mPa.s, when measured as a 2% solution in water at 20°C.
Suitable examples of HEC include the CELLOSIZE™ brand HECs available from Hϋls America, Inc. in Piscataway, New Jersey. Thus, CELLOSIZE brand QP 4400, QP 15,000, QP 30,000, QP 52,000, and QP 100,000 are examples of commercially available HECs, with QP 30,000 being a preferred HEC.
Suitable examples of EHEC include the BERMOCOLL™ E brand EHECs, available from Bero Nobel AB in Stennungsund, Sweden. Thus, BERMOCOLL brand E230, E270, E320, E351, E411, E431, E451, and E481 are examples of suitable EHECs. E230, E270, and E320 have an ethyl content of 0.8 mole per anhydroglucose unit and a hydroxyethyl content of 0.8 mole per anhydroglucose unit. E230, E270, and E320 have a Brookfield viscosity (Type LV) of respectively, 300±60, 700+ 150, and 2,200±450 mPa.s, when measured as a 2% solution in water at 20°C, at spindle speeds, respectively of 1-12, 2-12, and 3-12. E351, E411, E431, E451, and E481 have an ethyl content of 0.8 mole per anhydroglucose unit and a hydroxyethyl content of 2.1 mole per anhydroglucose unit. E351 has a Brookfield viscosity (Type LV) of 5,000 ± 1,000 when measured as a 2% solution in water at 20°C, at a spindle speed of 3-12. E411, E431, E451, and E481 have a Brookfield viscosity (Type LV) of respectively, 1,000 ±200, when measured as a 1% solution in water at 20°C, at a spindle speed of 2-12, and 2,000±400, 3,000±600, and 5,000± 1,000, when measured as a 1% solution in water at 20°C, at a spindle speed of 3-12. Any suitable amount of the thickening agent can be used in the preparation of the ink. It is typically used in an amount of from about 0.5% by weight to about 3% by weight of the ink, and preferably in an amount of from about 1% by weight to about 3% by weight of the ink. Excessive use of the thickening agent will have adverse consequences such as instability of the ink.
HUMECTANTS
The water phase of the present inventive ink may preferably comprise a humectant which prevents the loss of water from the ink by evaporation. The humectant may also serve as an antifreeze agent. Any suitable humectant known to those of ordinary skill in the art can be used. As the humectant component, use can be made of aliphatic polyols, and preferably glycerin and alkylene glycols in which the alkylene group preferably contains 2-6 carbon atoms, as represented by ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, and the polyalkylene glycols as represented by diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, and tetraethylene glycol. It is also possible to employ as humectant commercially available polyalkylene glycols such as Carbowax 200 or Carbowax 400, which are polyethylene glycols having average molecular weights of bout 200 and 400, respectively. In general, it is preferred, when using polyalkylene glycols, to use those materials having an average molecular weight less than 600 since higher molecular weight polyalkylene glycols frequently serve to undesirably increase the viscosity of the ink composition.
Any suitable amount of the humectant can be used in the preparation of the ink. It is typically used in an amount of from about 1% by weight to about 10% by weight of the ink, and preferably in an amount of from about 2% by weight to 7% by weight of the ink. Excessive use of the humectant will increase the viscosity of the ink undesirably. GENERAL
The ink composition of the present invention can have any suitable proportions of the oil and water phases. The ink composition typically contains the oil phase in a proportion of from about
15% by weight to about 80% by weight of the composition, preferably in a proportion of from about 20% by weight to about 50% by weight of the ink composition, and more preferably in a proportion of from about 25% by weight to about 40% by weight of the ink composition.
The following examples further illustrate the present invention.
Example 1 This example illustrates the preparation of an encapsulated colorant.
The following ingredients were used.
Wt.%
TUFFLO 2000 oil 30.0
Mineral seal oil 10.0 RESINALL 514 Resin 6.0
LX 2000 Resin (phenol modified hydrocarbon Resin) 4.0
AC 656 oxidized polyethylene 2.0
PRIMEX SSF disperser vehicle 8.0 MONARCH 120 carbon black 40.0
The encapsulated colorant was prepared as follows. TUFFLO 2000, RESINALL 514, and LX 2000 were combined in a HIDROBAT-10 mixer, and stirred for one hour at 160°C when the resins completely dissolved. The temperature was then reduced to 130°C and AC 656 was added and mixed for about 20 minutes. PRIMEX SSF was then added and mixed for about 10 minutes. The temperature was then reduced to 110°C, the mineral seal oil was added and mixed, and MONARCH 120 was added slowly over a period of about 10 to about 20 minutes. The mixing was continued for about 1 hour after the addition of carbon black to obtain the encapsulated colorant. Examples 2-8
These examples illustrate the preparation and performance of water-in-oil emulsion inks of the present invention. The following ingredients were used as set forth below for each of the examples.
Example 2 The Oil Phase
Figure imgf000024_0001
The Water Phase
Figure imgf000024_0002
The ink of the example 2 had a plastic viscosity of 13,355 cP (or mPa-s) and a yield stress of 3,608 dynes/cm2 (or N/m2), with a Confidence of Fit of 98.3%. The ink also had a consistency index of 235,965 cP (or mPa-s) and a flow index of 0.33 with a Confidence of Fit of 98.6%. The amount of ink used for the measurement was 2.2 gm and the measurements were done at a temperature of 20°C. Example 3
The Oil Phase
Figure imgf000025_0001
The Water Phase
Figure imgf000025_0002
Example 4
The Oil Phase
Figure imgf000026_0001
The Water Phase
Figure imgf000026_0002
For each example (example 2-4), the Filtrez 681 resin was pre-dissolved in hot (170°C) Agrisolv H oil, the ingredients of the oil phase were combined and blended in a suitable mixer, blended and passed through a three-roll mill. The milled materials were then mixed in a suitable mixer or blender. The pre-prepared water phase was then added slowly to form a water-in-oil emulsion ink. The mixing was continued until a uniform smooth emulsion ink was obtained. Example 5 The Oil Phase
Figure imgf000027_0001
The Water Phase
Figure imgf000027_0002
Example 6 The Oil Phase
Figure imgf000028_0001
The oil phase was prepared as following. Tufflo Process Naphthenic oil 2000 oil, Agrisolv H oil, Resinall 514, and Filtrez 681 were combined in a suitable mixer and stirred at 170°C until the resins were completely dissolved. The temperature was then reduced to 110°C, the Primex SSF was then added and mixed for about 10 minutes, and Monarch 120 was added slowly with mixing. The mixing was continued for about two hours after the addition of carbon black, and then passed through a three-roll mill. The milled materials were then mixed with sorbitan monooleate, Actiflo 68 UB, Extac 52, and mineral seal oil in a suitable mixer or blender. The pre-prepared water phase was added slowly with mixing to form a water-in-oil emulsion ink. The mixing was continued until a uniform smooth emulsion ink was obtained.
Example 7 The Oil Phase
Figure imgf000029_0001
The Water Phase
Figure imgf000029_0002
The oil phase was prepared as following. Varnish C-135, Tufflo Process Naphthenic oil
2000 and 40 Plus Base Black were mixed well in a suitable mixer, and were then passed through a three-roll mill. The milled materials were then mixed with sorbitan monooleate, Actiflo 68 UB, Extac 52, and mineral seal oil in a suitable mixer or blender to obtain the oil phase. The water-in-oil emulsion ink was prepared following the procedure set forth in examples 2-4. Example 8 The Oil Phase
Figure imgf000030_0001
The Water Phase
Figure imgf000030_0002
The oil phase was prepared as following. Resin Filtrez 681 was dissolved in the mixture oils of Sunpar 150 oil and Agrisolv H oil at about 170°C to obtain a varnish. This varnish was then mixed well with Converse SW-6500 black base in a suitable mixer, and were then passed through a three-roll mill. The milled materials were then mixed with sorbitan monooleate, Actiflo 68 UB, Extac 52, and mineral seal oil in a suitable mixer or blender to obtain the oil phase. The water-in-oil emulsion was prepared following the procedure set forth in examples 2-4. In each example, the ink had suitable physical properties and was tested on the commercially available RISOGRAPH® GR 1700 Digital Duplicator. Good printed imaging density, imaging rub resistance, and ink dry time, ink show-through, ink stability, and set-off free were obtained.
The ink's physical properties are measured using a Brookfield Cone Plate Rheometer, Model
HBDV-III CP with CP-52 cone spindle, at a measuring temperature of 20°C. See, Operating
Instruction, Manual No. M/91-210-D493, from Brookfield Engineering Laboratories, Inc. The Plastic Viscosity (cP or mPa-s) and the Yield Stress (Dynes/cm2 or N/m2) of the water-in-oil emulsion ink were obtained from the Bingham Plastic Analysis Math model with Confidence of Fit of 95% or above. The Consistency Index (cP or mPa-s) and Flow Index of the water-in-oil emulsion ink were obtained from the Power Law Analysis Math model with Confidence of Fit of 95% or above. The program used for both models is as follows: Speed increment: 2.5 RPM
Speed Ramp Interval: 00:30 second
Set Speed: 2.5 RPM
Wait for Speed: 15.0 RPM
Ink sample for Brookfield measurement: 2.0-2.5 grams, and 24 hours after manufacture.
Reference for the measurement: Brookfield Rheocalc for Windows, Operating Instructions, Manual No. M/95-2211.

Claims

CLAIMS:
1. A water-in-oil emulsion ink for use in digital duplicators comprising an oil phase and a water phase, said oil phase comprising a colorant and sufficient gelling and/or thickening agent to result in an ink having a yield stress of about 2,000 to about 8,000 dynes/cm2.
2. A water-in-oil emulsion ink for use in digital duplicators comprising an oil phase and a water phase, said oil phase comprising a colorant and sufficient gelling and/or thickening agent to result in an ink having a consistency index of about 100,000 to about 500,000.
3. A water-in-oil emulsion ink for use in digital duplicators comprising an oil phase and a water phase, said oil phase comprising an encapsulated colorant, said ink having a yield stress of about 2,000 to about 8,000 dynes/cm2.
4. A water-in-oil emulsion ink for use in digital duplicators comprising an oil phase and a water phase, said oil phase comprising an encapsulated colorant, said ink having a consistency index of about 100,000 to about 500,000.
5. An ink according to any one of the preceding claims wherein the ink also comprises in the oil phase one or more additional components selected from the group consisting of (1) phenolic modified esters of rosin, (2) gelled oils, (3) co-emulsifier, and (4) a non-drying oil or a combination comprising a non-drying vegetable oil and petroleum distillate.
6. An ink according to any one of the preceding claims having a plastic viscosity from about 6,000 to about 20,000 cp.
7. A water-in-oil emulsion ink for use in digital duplicators comprising an oil phase and a water phase, said oil phase comprising an encapsulated colorant and one or more additional components selected from the group consisting of (1) phenolic modified esters of rosin, (2) gelled oils, (3) co-emulsifier, and (4) a non-drying oil or a combination comprising a non-drying vegetable oil and petroleum distillate.
8. An ink according to any one of the preceding claims wherein the water phase is substantially free of thickening and gelling agents.
9. A digital duplicating process comprising using as the duplicating ink a water-in-oil emulsion ink according to any one of the preceding claims.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008103695A1 (en) * 2007-02-21 2008-08-28 Sanford, L.P. Permanent ink compositions and writing instruments containing same
US7843943B2 (en) 2007-11-21 2010-11-30 Nokia Corporation Differentiation for bandwidth request contention
US8430475B2 (en) 2008-06-25 2013-04-30 Hewlett-Packard Development Company, L.P. Inkjet ink and method of making the same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996036672A1 (en) * 1995-05-19 1996-11-21 Videojet Systems International, Inc. Duplicating inks for digital duplicators
EP0846737A1 (en) * 1996-12-06 1998-06-10 Riso Kagaku Corporation Emulsion ink for stencil printing

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996036672A1 (en) * 1995-05-19 1996-11-21 Videojet Systems International, Inc. Duplicating inks for digital duplicators
US5622548A (en) * 1995-05-19 1997-04-22 Micap Technology Corp. Duplicating inks for digital duplicators
EP0846737A1 (en) * 1996-12-06 1998-06-10 Riso Kagaku Corporation Emulsion ink for stencil printing

Cited By (7)

* Cited by examiner, † Cited by third party
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WO2008103695A1 (en) * 2007-02-21 2008-08-28 Sanford, L.P. Permanent ink compositions and writing instruments containing same
GB2456726A (en) * 2007-02-21 2009-07-29 Sanford Lp Permanent ink compositions and writing instruments containing same
JP2010519391A (en) * 2007-02-21 2010-06-03 サンフォード エル．ピー． Permanent ink composition and writing instrument containing the composition
GB2456726B (en) * 2007-02-21 2011-11-02 Sanford Lp Permanent ink compositions and writing instruments containing same
US8741039B2 (en) 2007-02-21 2014-06-03 Sanford, L.P. Permanent ink compositions and writing instruments containing same
US7843943B2 (en) 2007-11-21 2010-11-30 Nokia Corporation Differentiation for bandwidth request contention
US8430475B2 (en) 2008-06-25 2013-04-30 Hewlett-Packard Development Company, L.P. Inkjet ink and method of making the same

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