Classifications

• • 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
  • C09D11/10—Printing inks based on artificial resins
  • C09D11/102—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions other than those only involving unsaturated carbon-to-carbon bonds
  • C09D11/104—Polyesters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/68—Polyesters containing atoms other than carbon, hydrogen and oxygen
  • C08G63/688—Polyesters containing atoms other than carbon, hydrogen and oxygen containing sulfur
  • C08G63/6884—Polyesters containing atoms other than carbon, hydrogen and oxygen containing sulfur derived from polycarboxylic acids and polyhydroxy compounds
  • C08G63/6886—Dicarboxylic acids and dihydroxy compounds

Definitions

• This invention concerns aqueous inks having improved resistance to blocking which contain certain water-dissipatable polyesters .
• U.S. 4,052,368 claims certain water-dispersible hot melt adhesives based on sulfo polyesters that contain from 0 to 10 mol % polyoxyalkylene glycols and/or from 0 to 100 mol % ethylene glycol. This disclosure did not recognize that any of the sulfo polyesters described might have utility in printing inks or overprints.
• U.S. 4,340,519 discloses an aqueous dispersion of at least two sulfo polyesters useful for printing inks . At least one sulfo polyester must be crystalline and at least one sulfo polyester must be non-crystalline. To obtain an aqueous dispersion of the sulfo polyesters from 2 to 66% of a water-soluble organic compound is required because of the low ( ⁇ 10 mol %) sulfo substitution level in the claimed polyesters.
• U.S. Patents 4,704,309 and 4,847,316 disclose printing processes employing water-dispersible inks based on sulfo polyesters containing at least 0.1 mol % of a polyethylene glycol. These patents do not recognize that improved inks or overprints can also be prepared from certain sulfo polyesters containing no polyethylene glycols.
• the present invention is directed to certain ink and overprint compositions that have improved properties, especially block resistance, as compared to prior art compositions .
• the ink compositions of the present invention contain polyesters which have certain levels of sulfomonomer and certain types of glycols.
• composition useful as an ink, overprint, or concentrate thereof comprising:
• (D) 0 to about 5 weight % (based on the weight of total dry wax solids) of an emulsified, dispersed, powdered or micronized wax.
• the advantages of this invention are achieved by incorporating the amorphous water-dispersible polyesters described herein into water-borne ink compositions.
• the term "ink composition” and like terms will be used in its broad sense, that is, to include concentrates thereof, primers, and overprints or overprint varnishes .
• Overprints typically have low levels of colorant or no colorant.
• the polyesters useful in the present invention have the feature of containing certain levels of a sulfomonomer having a sulfonate group attached to an aromatic nucleus and the additional feature of containing no diethylene glycol or higher polyethylene glycol residues in the polymer chain.
• component (A) preferably comprises from about 2 to about 25 weight percent, more preferably from about 5 to about 20 weight percent.
• component (B) preferably comprises 0 to 35 weight percent.
• component (B) preferably comprises about 0.5 to about 50 weight percent, more preferably about 0.5 to about 35 weight percent and most preferably about 5 to about 35 weight percent.
• component (C) preferably comprises about 50 to about 90 weight percent.
• component (D) usually comprises from about 0.01 to about 5 weight percent, preferably about 0.01 to about 3 weight percent, more preferably about 0.1 to about 3 weight percent, and most preferably about 0.2 to about 2 weight percent.
• the wax can be incorporated into inks in either a dry form or non-dry form (e.g., emulsified); however, the amount of wax (i.e., component (D) ) in the ink composition is based on the weight of the dry wax solids .
• the ink composition of the invention is a finished ink or concentrate thereof, such composition will contain at least one colorant. Such compositions have at least about 0.5 weight percent of colorant. More typically, in such ink compositions, at least about 5 weight percent of colorant is present. If the ink composition contains an organic pigment, typically such an organic pigment is present in an amount of about 17.5 weight percent or less of the total composition. If the ink composition contains an inorganic pigment, typically such inorganic pigment is present in an amount of about 50 weight percent or less of the total composition.
• the glycol component of the polyester of the present invention is an aliphatic, alicyclic, or aralkyl glycol. These glycols are distinguishable from the glycols used to prepare certain prior art polyesters in that they do not contain an oxygen atom in the backbone of the molecule (i.e., no ether linkage).
• the glycol i.e., component (A)(4)
• the glycol is an aliphatic glycol containing 2 to 8 carbon atoms, an alicyclic glycol containing 6 to 12 carbon atoms or a mixture thereof.
• Suitable glycols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,3-butanediol, 2,2-dimethyl- 1,3-propanediol, 1,2-cyclohexanedimethanol, 1,4-cyclo- hexanedimethanol, p-xylenediol, or a mixture thereof.
• glycols are 1,4-cyclohexane ⁇ dimethanol; 1,3-cyclohexanedimethanol; 2,2-dimethyl- 1,3-propanediol; p-xylenediol, and ethylene glycol.
• ethylene glycol the polymeriza ⁇ tion mixture must be buffered with, for example, sodium acetate, to help prevent the in situ formation of diethylene glycol and higher polyethylene glycols, which would then be incorporated into the polymer and could result in undesirable properties such as reduced blocking resistance.
• Suitable dicarboxylic acids, or esters thereof (components (A)(1) and (A)(2)), and difunctional sulfo monomers (component (A)(3)) are given in U.S. Patents 3,734,874 and 3,779,993, incorporated herein by reference in their entirety.
• the aromatic dicarboxylic acids (component (A)(1)) preferably contain 8 to 14 carbon atoms and the aliphatic or cycloaliphatic dicarboxylic acids preferably contain 4 to 20 carbon atoms.
• components (A)(1) and (A)(2) do not contain a sulfomonomer.
• component (A)(1) include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalene dicarboxylic acid, or a mixture thereof.
• component (A)(2) include glutaric acid, succinic acid, adipic acid, trimethyladipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,4- ⁇ yclohexanedi ⁇ arboxylic acid, or a mixture thereof.
• dicarboxylic acids are isophthalic acid and terephthalic acid.
• component (A)(3) is a metal or ammonium salt of a sulfoaromatic dicarboxylic acid.
• Examples of the metal of the metal salt include lithium, sodium, potassium, magnesium, calcium, copper, or iron. Preferred are sodium and lithium with sodium being most preferred. It is preferred that the sulfomonomer contains 8 to 14 carbon atoms.
• suitable sulfomonomers include a metal salt of sulfo- terephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7- dicarboxylic acid, 5- (4-sulfophenoxy)isophthalic acid, or a mixture thereof.
• the preferred sulfomonomers are 5-sodiosulfoiso- phthalic acid and 5-lithiosulfoisophthalic acid or the dimethyl esters thereof.
• Preferred polyesters of the present invention are wherein component (A)(2) is isophthalic acid, terephthalic acid, or a mixture thereof, component (A)(2) is not present (i.e., 0 mole %), component (A)(3) is 5-sodiosulfoisophthalic acid, 5-lithiosulfoisophthalic acid, or a mixture thereof, and component (A)(4) is 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 2,2-dimethyl-1,3-propanediol, ethylene glycol, p-xylenediol, or a mixture thereof.
• component (A)(1) is about 35 to 85 mole % isophthalic acid, 0 to about 35 mole % 2,6-naphthalene dicarboxylic acid, and 0 to about 45 mole % terephthalic acid
• component (A)(3) is about 18-22 mole % 5-sodiosulfoisophthalic acid
• component (A)(4) is 0-100 mole %, 1,4-cyclohexane- dimethanol, 0-100 mole % 2,2-dimethyl-1,3-propanediol, and 0-100 mole % ethylene glycol.
• Glass transition temperature (Tg) of the sulfo polyesters is determined by heating a small sample of finely divided polymer to about 130°C (well above the expected Tg) , quenching the sample with liquid nitrogen, then reheating at a rate of 20°C/min in a Du Pont
• the Tg is taken as the mid-point of an abrupt base line shift in a plot of heat flow versus sample temperature.
• the Tg is greater than about 60°C, preferred is greater than about 70°C.
• the ink compositions of the present invention when printed on a substrate do not block below about 100°F (37.78°C); more preferably do not block below about 120° to 220°F (48.89° to 104.44°C), when heated for 5 seconds on a Sentinel Heat Sealer at 40 psi (275.79 kilopas ⁇ al).
• inks of this invention is an increased resistance to blocking of printed matter. Both ink-to-ink and ink-to-paper blocking is reduced. This improvement is especially beneficial when printed matter is exposed to warm humid climates .
• the inks and overprints of this invention are superior to those described by Coney et al (U.S. 4,704,309), in that the sulfo polyesters of this invention contain no diethylene glycol or polyethylene glycol residues. It is not desired to be bound by any particular theory or mechanism; however, it is believed that the presence of these hydrophilic glycols residues in sulfo polyesters increases the tendency of inks prepared therefrom to block as relative humidity increases.
• Waxes i.e., component (D)
• Waxes of many chemical types are preferably incorporated into printing inks and overprint varnishes of the present invention to impart improved properties such as mar-resistance, improved slip and water repellency properties.
• Waxes are normally introduced to inks and overprint varnishes in one of two ways: (1) wax of a controlled fine particle size, i.e., powdered or micronized, is mixed or ground into the ink or overprint along with pigments, if any, or (2) waxes are dispersed, emulsified or dissolved in the ink medium (i.e., in water in the case of the water- borne inks and overprint varnishes of the present invention) and added to the ink or overprint varnish formulation.
• wax of a controlled fine particle size i.e., powdered or micronized
• pigments if any
• waxes are dispersed, emulsified or dissolved in the ink medium (i.e., in water in the case of the water- borne inks and overprint varnishes of the present invention) and added to the ink or overprint varnish formulation.
• waxes are usually divided into three broad classifications: synthetic waxes, petroleum waxes and natural waxes .
• waxes vary in their efficacy in the inks and overprints of this invention, useful examples of waxes are found in all three classifications.
• synthetic waxes such as polyethylene waxes, both as fine powders (micronized form) and as emulsions in water, are preferred.
• polytetrafluoroethylene waxes in powder form are also preferred.
• waxes useful in this invention include Jonwax (trademark) 26 and Jonwax 120 [available from S. C. Johnson and Sons, Inc., Racine, Wisconsin 43403 (U.S.A.)], Vanwax (trademark) 35 [available from Vantage, Garfield, New Jersey 07026 (U.S.A.)] and Epolene (trademark) E waxes [available from Eastman Chemical Products, Inc.,
• the ink compositions can optionally contain up to about 15 weight percent, preferably up to about 3 weight percent of one or more other additives .
• additives include surfactants such as Surfynol (trademark) 104 and Surfonyl 440 (available from Air Products and Chemicals, Allentown, Pennsylvania 18105); modifiers (for example, defoamers) such as Resolv (trademark) (available from Vantage), Foamaster (trademark) 111 (available from Henkel Corporation, Morristown, New Jersey 07960); alcohols such as n-propyl alcohol, isopropyl alcohol, ethanol, methanol or glycol ethers derived from reaction of alcohols or glycols with ethylene oxide and/or propylene oxide such as ethylene glycol, propylene glycol, ethylene glycol monobutyl ether or propylene glycol monobutyl ether; biocides; pH stabilizers; dispersants; thickeners such as A ⁇ rysol (trademark) RM-825 (available from Rohm &
• pH stabilizers it is desirable to add a small amount of one or more pH stabilizers to the ink compositions to keep the pH within a desired range. For example, it is common to add about 0.1 weight percent sodium acetate to an ink or aqueous solution/dispersion of polymer.
• Preferred amounts of an alcohol are about 0.1 to about 10 weight percent, more preferred is about 0.5 to about 8 weight percent.
• the presence of one or more alcohols is particularly advantageous to enhance surface wetting properties.
• the ink composition of the invention is printed onto a substrate selected from metal foil, newsprint, bleached and unbleached kraft paper, clay coated paper, glass, calendered paper, stainless paper, paper board, and films or other substrates of polyester, polycarbonate, cellulose ester, regenerated cellulose, poly(vinylidene chloride), polyamide polypropylene, polyethylene or polystyrene. It is also preferred that after the ink composition is printed, a substantial portion of the initial metal cations of the water solubilizing sulfonate groups of the water-dissipatable polyester material has been replaced with an insolubilizing polyvalent metal cation,
• +3 ++ such as Al , Ca , or the like as disclosed and in the manner described in U.S. Patents 4,145,469, and
• the inherent viscosities (I.V.) of the particular water-dissipatable polyesters useful herein are at least 0.1 dL/g and preferably range from about 0.1 to about 1.0 dL/g, most preferably from about 0.2 to about 0.4 dL/g, determined according to ASTM D2857-70 procedure, in a Wagner Viscometer of Lab Glass, Inc., of Vineland, New Jersey, having a 1/2 L capillary bulb, using a polymer concentration about 0.5% by weight in 60/40 by weight of phenol/tetrachloroethane.
• the procedure is carried out by heating the polymer/solvent system at 120°C for 15 minutes, cooling the solution to 25°C and measuring the time of flow at 25°C.
• the I.V. is calculated from the equation
• inherent viscosity at 25°C at a polymer concentration of 0.5 g/100 mL of solvent
• the ink compositions of this invention can be for any of the typical ink applications such as flexo- graphic, gravure, letterpress, ink-jet, or screen- process printing applications.
• the ink compositions of the present invention have excellent adhesion to a wide variety of substrates including plastic films such as polyester, polyethylene or polypropylene; aluminum foil; glass; and paper.
• the ink compositions of the present invention should have a pH of about 8.2 or lower; preferred is a pH of about 7 to 8. If the pH is higher than about 8.2, there is a danger of the polymer(s) hydrolyzing which may result in gelling of the system.
• the polyesters of this invention can be dispersed in water for ink preparation by the procedure given in U.S. 4,704,309, Col. 3, Line 52 to Col. 4, Line 6.
• the following procedure can be used for dispersing the polyester in water:
• the water should be preheated to about 180°F (82.22°C) to about 200°F (93.33°C) and the polyester in pellet form is added rapidly to the vortex under high shear stirring.
• a Cowles Dissolver, Waring (trademark) blender, or similar equipment may be used. Once the water is heated to the desired temperature, additional heat input is not required.
• dispersion of the pellets should be complete within 15 to 30 minutes stirring. Continued agitation with cooling may be desirable to prevent thickening at the surface due to water evaporation. Viscosities of the dispersions remain low up to polyester levels of 25 percent to 30 percent and viscosities increase sharply above these levels.
• Viscosities of the dispersions will be influenced by the degree of polymer dispersion obtained which is affected by the dispersing temperature, shear, and time.
• the polyester content typically may range from about 15 percent to about 40 percent by weight of the aqueous dispersion with the preferred for most applications being from about 20 percent to about 35 percent.
• the inks, overprints, and primers of this invention can be prepared, for example, as disclosed in U.S. Patents 4,148,779 and 4,704,309, which are incorporated herein by reference in their entirety.
• the printing ink, overprint, or primer may be prepared as follows : The colorant is added to the polymer blend dispersion and, at a properly adjusted viscosity, dispersed thereinto with ball mill, sand mill, high-shear fluid flow mill, Cowles Dissolver, Katy Mill or the like.
• the colorants also may be dispersed directly in the polymer by milling on a heated two-roll mill at about 220° to 360°F (104.44° to 182.22°C) and using processing aids as desired, such as solvents or plasticizers.
• processing aids such as solvents or plasticizers.
• the viscosity and printing characteristics of the ink composition may be modified further by addition of water, solvents, plasticizers, sequestered wax, surfactants and the like to suit the particular printing needs .
• the amounts and nature of these optional additives have been previously described herein.
• the present invention is not limited to any type of dye, pigment, filler, or the like, all of which are hereinafter included in the term "colorant, " and can accommodate any colorant which can be dispersed, milled, mixed, blended or dissolved in any manner in either the polymer blend, water or aqueous polymer system.
• Exemplary useful C.I. pigments for use in the present invention are given in the following table:
• C.I. Pigment Yellow 151 A diazotized aniline derivative coupled with an acetoacetyl derivative of 5-aminobenzimidazolone
• C.I. Pigment Orange 5 2-Naphthalenol, 1- [(2,4-dinitro- phenyl)azo] - Generic Name CA. Index/Chemical Name
• ink compositions disclosed herein may be superior over prior aqueous ink compositions in one or more of such properties as pigment wetting, pigment stability, temperature stability (heat and freeze-thaw) , non- settling for extended periods of time, nonpolluting with respect to odor and volatile organics, non- flocculating, long "open" time in the press fountain, wide viscosity range inks, adhesion to a variety of substrates, hardness, gloss, drying rate on substrates, film-forming properties at low temperatures without organic co-solvents, resistance to grease, water and scuff, compatibility with other water-based inks, wet rub resistance, ink mileage characteristics (consider- able water dilution allowable at the press), ink press stability in general, printability (clean, sharp transfer without “stringing or misting"), trapping, easy clean up, nonplugging of printing plates, flexibility, redispersibility or rewetting, c
• a 500-mL round-bottom flask equipped with an agitator shaft, nitrogen inlet and distillation sidearm is charged with 78.6 g (0.405 mol) of dimethyl isophthalate, 28.1 g (0.0950 mol) of dimethyl 5-sodiosulfoisophthalate, 79.2 g (0.550 mol) 1,4-cyclohexanedimethanol, 0.078 g sodium acetate (buffer) and about 100 ppm (based on final polymer weight) titanium catalyst as titanium tetraisopropoxide.
• the flask is immersed in a Bel ont metal bath at 200°C for two hours with stirring under a nitrogen sweep. Approximately 1.0 mol of methanol, the ester interchange reaction product, is removed through the distillation sidearm. The temperature of the bath is then increased stepwise over a period of about 45 minutes to 285°C
• the reaction flask and sidearm are rigged for operation under vacuum. Pressure in the flask is gradually reduced over a period of about 30 minutes to less than 0.5 torr. During this time the viscosity of the reaction mixture increases as the polymer molecular weight increases .
• the flask is removed from the molten metal bath and dry nitrogen gas is bled into the flask. When cooled to room temperature, the polymer is removed from the flask and ground into a coarse powder.
• the I.V. of the polymer is 0.22 dL/g
• the second cycle Tg of the polymer (after quenching from the melt) is 84°C and the sulfur content of the polymer is 1.93%.
• Example 1 is sifted into 150 g of demineralized water in a 3-necked flask equipped with a stirrer, and a temperature controlled heating mantle. After 15 minutes at room temperature, the temperature of the flask is increased stepwise to 95°C over a period of 30 minutes. The polymer particles became highly swollen and gradually disperse over a period of about 1 hour. The flask is cooled to about 60°C, at which point the dispersion is filtered to remove a small fraction of undispersed particles. The resulting dispersion has a viscosity of 120 cP (Brookfield Viscometer, Model RVT, Spindle No. 3, 100 rpm) and is found to contain 25.2% nonvolatile matter.
• 120 cP Brookfield Viscometer, Model RVT, Spindle No. 3, 100 rpm
• An aqueous ink suitable for printing on paper, film or foil substrates is prepared by blending the following components in a high speed mixer: Ink Formula ispersion from Example 2 (25% solids) thylene glycol monobutyl ether -propanol crylic thickener (Aerysol RM825 from Rohm & Haas)
• Ink viscosity is adjusted to 25 seconds, No. 3 Zahn cup, for printing by addition of water and/or n-propanol as required.
• the pigment is omitted from the formulation.
• This fold is inserted in between the pre-heated (100°F, 37.78°C) platens of a Sentinel Heat Sealer (Packaging Industries, Inc., Hyannis, Mass., Model 12 ASL) .
• the heat sealer is activated to compress the folded paper strip between the heated platens for 5 seconds at 40 psi (275.79 kilopascal) .
• the fold is carefully opened to inspect for ink-to-ink sticking or blocking. If no blocking is detected, the temperature of the platens is increased in 10°F (5.56°C) increments and the test is repeated until blocking occurs .
• the lowest temperature at which ink film sticking results in paper tear is taken as the blocking temperature of the ink. In this way, the blocking temperature of the ink from Example 3 is determined to be 140°F (60°C) .
• Examples 1-4 the water-dispersible polyesters listed in Table 1 were prepared, dispersed, formulated into inks and tested for ink blocking temperature.
• the sulfo polyesters of Examples 5-9 are illustrative of the present invention, i.e., they contain no diethylene glycol or polyethylene glycols. Ink blocking temperature for all of these polyesters is well above 100°F (37.78°C). In contrast, the ink blocking temperature of the sulfo polyester of Example 10 (an example from the prior art) is less than 100°F (37.78°C) .

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• Chemical & Material Sciences (AREA)
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• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
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• Polymers & Plastics (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)

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• 1990
  • 1990-10-26 JP JP51569090A patent/JPH05501428A/ja active Pending
  • 1990-10-26 WO PCT/US1990/006257 patent/WO1991006608A1/en not_active Application Discontinuation
  • 1990-10-26 EP EP19900916860 patent/EP0500677A1/de not_active Ceased
  • 1990-10-26 CA CA 2073016 patent/CA2073016A1/en not_active Abandoned

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