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
  • C09D11/30—Inkjet printing inks
  • C09D11/32—Inkjet printing inks characterised by colouring agents
  • C09D11/328—Inkjet printing inks characterised by colouring agents characterised by dyes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/0023—Digital printing methods characterised by the inks used
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B1/00—Dyes with anthracene nucleus not condensed with any other ring
  • C09B1/16—Amino-anthraquinones
  • C09B1/20—Preparation from starting materials already containing the anthracene nucleus
  • C09B1/26—Dyes with amino groups substituted by hydrocarbon radicals
  • C09B1/28—Dyes with amino groups substituted by hydrocarbon radicals substituted by alkyl, aralkyl or cyclo alkyl groups
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B1/00—Dyes with anthracene nucleus not condensed with any other ring
  • C09B1/16—Amino-anthraquinones
  • C09B1/20—Preparation from starting materials already containing the anthracene nucleus
  • C09B1/26—Dyes with amino groups substituted by hydrocarbon radicals
  • C09B1/32—Dyes with amino groups substituted by hydrocarbon radicals substituted by aryl groups
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B62/00—Reactive dyes, i.e. dyes which form covalent bonds with the substrates or which polymerise with themselves
  • C09B62/002—Reactive dyes, i.e. dyes which form covalent bonds with the substrates or which polymerise with themselves with the linkage of the reactive group being alternatively specified
  • C09B62/0025—Specific dyes not provided for in groups C09B62/004 - C09B62/018
• • 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
  • C09D11/03—Printing inks characterised by features other than the chemical nature of the binder
  • C09D11/037—Printing inks characterised by features other than the chemical nature of the binder characterised by the pigment
• • 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
  • C09D11/101—Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
• • 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
  • C09D11/106—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C09D11/107—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from unsaturated acids or derivatives thereof

Definitions

• the present invention relates to a curable ink composition, in particular a curable inkjet ink composition.
• the ink is for radiation curing, for example, UV curing.
• ink compositions a number of factors must be balanced in order to avoid or reduce the problems associated with ink compositions.
• one or more monomers are present in the ink typically with a
• the curing process involves treating the printed ink composition with UV radiation for example UV light from a
• LED light-emitting diode
• mercury vapour arc lamp mercury vapour arc lamp
• the monomers may be mono-functional or multi-functional (e.g. di-functional or tri-functional) monomers.
• the polymerization initiator is typically a photoinitiator.
• Curable inks such as UV curable inks, provide a number of preferable features compared to other types of inks.
• curable inks can have a low volatile organic chemical content.
• UV-curable inks are usually coloured by the inclusion of pigments.
• Pigments are powdered substances that are relatively insoluble in the ink but can remain suspended within it.
• Soluble dye compounds are not commonly used in UV-curable inks, for example, due to their tendency to degrade under strong UV light sources.
• Pigments are typically more expensive than dyes and they require an extra‘milling’ step in ink manufacture (where the pigment is ground sufficiently finely to be well-suspended within the ink). Pigments can be more susceptible to printer nozzle blocking than dyes.
• One of the most significant challenges for the formulator of a UV-curable ink is how to keep the coloured pigments suspended adequately in the monomeric solvent. In addition to optimisation of the milling conditions, it is necessary to adequately match the desired pigment to the monomers and other additives in the ink, so as to create stable dispersions.
• small-molecule dyes degrade very rapidly when subjected to UV-irradiation such as the UV radiation used during the curing process. Additionally, small-molecule dyes are known to migrate out of the printed deposit, in particular when a solvent is applied.
• the dye In order for dyes to be used in UV curable inks, the dye must have certain properties such as the ability to withstand the UV radiation used to cure the ink, solubility in the ink composition and compatibility with printer hardware. For example, for drop on demand inkjet printing, inks typically need to have a low viscosity to be compatible with the printer hardware.
• an ink to produce a printed deposit that maintains its colouration (i.e. is colour-fast) over time, has good cure properties and good adhesion to the substrate.
• ink compositions that have some of the above desirable characteristics.
• dye compounds that are stable to UV radiation and provide compositions with good cure and colour fastness in the printed deposit.
• the present invention seeks to provide an ink composition which is suitable for curing and has good cure properties and/or good adhesion properties.
• the present invention seeks to provide a curable ink composition for use in drop on demand inkjet printing such as piezoelectric drop on demand inkjet printing.
• the present invention provides a curable ink composition
• a curable ink composition comprising a dye monomer, a carrier monomer and an initiator.
• the dye monomer has a chromophore moiety covalently bonded to at least one polymerizable functional group.
• the dye monomer is present at 1.0 wt % or more based on total weight of the ink composition.
• the carrier monomer has at least one polymerizable functional group and is present in at 50 wt % or more based on total weight of the ink composition.
• the carrier monomer may be a single monomer or may be a combination of two or more monomers.
• the dye moiety is stabilised by being covalently bound into the polymer network during the curing process.
• the present invention provides a printed deposit formed from the curable ink composition of the invention.
• the printed deposit comprises a cured polymer film formed by polymerisation of dye monomer and the carrier monomer.
• the curable ink composition is compatible with the components of a printer, for example an inkjet printer, and more particularly a drop on demand inkjet printer, such as a piezoelectric drop on demand inkjet printer.
• the curable ink composition is suitable for application directly onto products and/or product packaging to achieve high quality images.
• the curable ink composition described herein has a viscosity of about 0.5 to 30 mPa.s, more preferably from 1 to 20 mPa.s and even more preferably from 5 to 20 mPa.s at 25°C.
• the curable ink composition described herein has a viscosity of less than 25 mPa.s, more preferably less than 15 mPa.s at 25°C.
• the curable ink composition described herein has a viscosity of greater than 3 mPa.s, more preferably greater than 5 mPa.s, even more preferably greater than 8 mPa.s at 25°C.
• the viscosity of the composition may be measured using a viscometer such as a Brookfield DV-II+ viscometer.
• the Brookfield DV-II+ viscometer is a rotational viscometer which measures viscosity by measuring the torque required to turn an object in a fluid as a function of the fluid’s viscosity.
• the curable ink composition as described herein has a surface tension of from 20 to 50 mN/m, more preferably from 20 to 40 mN/m at 25°C.
• the surface tension of the composition may be measured using equipment such as a du Nouy ring tensiometer or using the pendant drop method on a KSV Cam 200 optical tensiometer.
• Figure 1 shows a reaction scheme for the synthesis of methacrylate-containing dyes 1a-5a.
• Figure 2 shows a UV-vis spectra of solutions of 1a-5a, dissolved at 0.01 % w/w in THF.
• Figure 3 is a photographs of solutions of compounds 1a-5a, dissolved in THF at 0.01% w/w.
• Figure 4 is a series of photographs showing the colour change of films containing the functionalised dyes.
• (Top Row) 1a-5a(i) methacrylated dye films before curing (Second Row) 1a-5a(ii) Methacrylated dye films after UV curing (Third Row) 1-5 Non-methacrylated dye films before curing (Fourth Row) Non-methacrylated dye films after curing.
• Figure 5 is a graph showing the differences in delta E values for the alcohol-functionalised dyes vs the methacrylate-functionalised dyes.
• Figure 6 is graph to showing the changing delta E values for both methacrylate- and alcohol- functionalised dyes during aging
• Figure 7 shows the effect of solvent soaking on cured films.
• Samples (a)-(d) contain 2% methacrylated dye 4a; the film has been cured for increasing cure times from a to d. For each sample, a photograph of the cured film is shown above a photograph of a vial containing the film soaked in 5 ml acetone for 24h.
• Samples (e)-(h) contain 2% hydroxylated dye 4; each film has been cured for the same time as the corresponding hydroxylated film above.
• Figure 8 shows photographs of (a) a logo printed from a solution containing the
• methacrylated dye 4a (b) the same film as in (a), after UV irradiation.
• the present invention seeks to provide a curable ink composition which is suitable for radiation curing and has good cure properties and/or good adhesion properties.
• the present invention seeks to provide a curable inkjet ink composition for use in drop on demand inkjet printing such as piezoelectric drop on demand inkjet printing.
• the present invention provides a curable ink composition
• a curable ink composition comprising a dye monomer, a carrier monomer and an initiator.
• the dye monomer has a chromophore moiety covalently bonded to at least one polymerizable functional group.
• the dye monomer is present at 1.0 wt % or more based on total weight of the ink composition.
• the carrier monomer has at least one polymerizable functional group and is present in at 50 wt % or more based on total weight of the ink composition.
• the carrier monomer may be a single monomer or may be a combination of two or more monomers.
• the curable ink composition may be curable inkjet ink composition.
• the curable ink composition may be a UV curable ink composition for example a UV curable inkjet ink composition for use in drop on demand inkjet printing.
• the present invention provides a printed deposit formed from the ink composition of the invention.
• the printed deposit comprises a cured polymer film formed by polymerisation of the dye monomer and the carrier monomer.
• the resulting printed ink deposit remains highly coloured after UV curing. It is proposed that the dye moiety is incorporated into the polymer structure of the cured film. In this way, the printed and cured deposit shows increased resistance to light fading compared to an unreacted, small-molecule dye on a surface.
• the dye monomer provides colour to the printed deposit meaning a pigment is no longer required in the ink.
• Pigments significantly increase the viscosity of curable ink compositions and so their addition to such ink compositions must be carefully controlled in order to provide a viscosity which is compatible with printer hardware.
• the present curable ink compositions do not exhibit increased viscosity.
• the inks of the present invention are preferably for use with a piezoelectric inkjet printer such as a piezoelectric drop on demand inkjet printer.
• a piezoelectric inkjet printer such as a piezoelectric drop on demand inkjet printer.
• the viscosity and surface tension of the ink will be dependant up on droplet size ejected by the printer and may be adjusted within the formulation principle disclosed to best suit the properties of the printer.
• ink may be heated to around 40°C to reduce the viscosity and facilitate ejection through the nozzles.
• the viscosity is preferably from 5 to 10 mPa.s at the temperature of application, for example at 40°C.
• the ink of the present invention may be useful for use in high speed printing applications. Such applications require the ejection of droplets at very high frequency from the nozzles of the printer and the residence time under the UV curing equipment is reduced at high speed.
• the inks of the present invention have low viscosities which are required for high speed ejection and exhibit improved cure allowing high speed curing processes.
• the ink should be capable of print speeds up to 50 m/min, more preferably up to 75 m/min and even more preferable up to 100 m/min.
• the curable ink composition of the invention comprises a dye monomer, a carrier monomer and an initiator.
• the dye monomer has a chromophore moiety covalently bonded to at least one polymerizable functional group.
• the dye monomer is present at 1.0 wt % or more based on total weight of the ink composition.
• the carrier monomer has at least one polymerizable functional group and is present in at 50 wt % or more based on total weight of the ink composition.
• the initiator may be a photoinitiator.
• the carrier monomer may be a single monomer or may be a combination of two or more monomers.
• the curable ink composition is preferably a curable inkjet ink composition.
• monomer used in the present application refers to a chemical compound which is capable of undergoing a polymerization either alone or with other monomers to provide a polymer.
• monomer refers to a chemical compound which is capable of undergoing polymerization when subjected to UV radiation in the presence of an initiator.
• the curable ink composition described herein has a viscosity of about 0.5 to 30 mPa.s, more preferably from 1 to 20 mPa.s and even more preferably from 5 to 20 mPa.s at 25°C.
• the curable ink composition described herein has a viscosity of less than 25 mPa.s, more preferably less than 15 mPa.s at 25°C.
• the curable ink composition described herein has a viscosity of greater than 3 mPa.s, more preferably greater than 5 mPa.s, even more preferably greater than 8 mPa.s at 25°C.
• the viscosity of the composition may be measured using a viscometer such as a Brookfield DV-II+ viscometer.
• the Brookfield DV-II+ viscometer is a rotational viscometer which measures viscosity by measuring the torque required to turn an object in a fluid as a function of the fluid’s viscosity.
• the curable ink composition contains a dye monomer having a chromophore moiety covalently bonded to at least one polymerizable functional group.
• Methacrylated anthraquinone dyes have been synthesised in previous studies (see
• the methacrylated anthraquinone dyes are polymerized either using radical initiators or by heating.
• the dyes and the polymerizable compositions are for use as colour stabiliser in paints, photo-resits in semiconductors and for iris implants. Such compositions are not suitable for inks and in particular inkjet printing inks.
• Chromophore containing monomers have also been discussed for use in coating applications (e.g. US 7030244 and US 6870063). In these cases, the chromophore containing monomer is copolymerized to for a coating. As is typical with coating
• compositions before polymerization the composition contains a large amount of a reactive polymer (40 wt%) and a consequently a lower amount of monomers.
• the coating is applied by spreading with a blade and is cured at a slow speed (less than 8 metres/min). As such, these coating compositions are unsuitable for printing techniques and in particular inkjet such as drop on demand inkjet printing.
• sensitising dyes are said to absorb radiation and transfer this energy to the polymerization initiators to initiate
• the sensitising dyes absorb UV light, preferably the sensitising dye have an absorption wavelength in the 350 nm to 450 nm range (see [0032]).
• the preferred absorption pattern in US 2009/0087575 A1 means that the sensitising dyes appear colourless.
• US 2009/0087575 A1 explains that in order to provide a coloured image, the ink composition contains a further colouring agent and this is the case in the examples which include an additional colourant.
• UV-range when present in a composition that is suitable for inkjet printing to allow the curing process to produce a good cure can occur. It is also desirable that the resulting printed deposit absorbs sufficient visible light for strong colouration and is colour-fast.
• the presently claimed curable ink compositions provide these properties.
• chromophore used in this context refers to a chemical group that provides colour to the dye monomer.
• a chromophore provides colour because the chromophore has two separate molecular orbitals the energy difference between which corresponds to the wavelength of light in the visible spectrum.
• the colouration observed is due to light that is not absorbed because the wavelength of this light does not correspond to the energy difference between the molecular orbitals.
• the chromophore moiety provides colour by absorbing light in the visible spectrum.
• the chromophore moiety provides colour by absorbing a majority of light in the visible light spectrum.
• the chromophore may absorb 50 % or more of light in the visible spectrum, preferably 60 % or more and even more preferably 80 % or more.
• the visible light spectrum is generally from about 380 nm to 740 nm.
• Absorbance may be calculated by measuring the transmittance of sample containing 5 ppm of the dye monomer using a spectrophotometer.
• the chromophore moiety may be selected from an anthraquinone, an anthrapyridone, an anthrapyrimidine, an anthrapyrimidine, an anthrapyrimidone, an isothiazoloanthrone, an azo dye, a bis-azo dye, a methine, a bis-methine, a coumarin, a 3-aryl-2,5-dioxypyrroline, a 3- aryl-5-dicyanomethylene-2-oxypyrroline, a perinone, a quinophthalone, a phthalocyanine, a metal phthalocyanine, a nitroarylamine, or a 2,5-diarylaminoterephthalic ester.
• the chromophore moiety is an anthraquinone.
• the anthraquinone may be single anthraquinone moiety or may be a made up of two or more anthraquinone moieties such as a 7,14-dibenzpyrenequinone or indanthrone.
• anthraquinone may be used interchangeably with anthracene-9, 10-dione or 9,10-dioxoanthracene.
• the anthraquinone chromophore moiety may be provided by an anthraquinone dye that is covalently bonded to a polymerizable functional group through a suitable atom of the anthraquinone dye such as a carbon, oxygen, nitrogen or sulphur atoms of the
• Anthraquinone dyes are well known and include disperse blue 14, reactive blue 4,
• Acid Blue 25 Alizarin, Anthrapurpurin, Carminic acid,
• the chromophore is covalently bonded to at least one polymerizable functional group.
• the covalent bond may be present between one or more suitable atoms in the chromophore, for example, by the abstraction of a hydrogen atom from a carbon, nitrogen, oxygen or sulphur atom in the chromophore.
• Each chromophore may be optionally substituted, for example, each chromophore may be optionally substituted with one or more halo, NH2, NHR’, aryl, heteroaryl, -SO3H, -OH, Ci-6alkly, Ci-6haloalkly, Ci-6alkoxy, -COOH, -CN and glucosyl wherein R’ may be Ci-6-alkyl, aryl-NH-heteroaryl, phenyl, tolyl optionally substituted with one or more groups selected from halo, -OH, -SO2H, and -S02CH2CH20S03Na.
• the dye monomer contains a polymerizable functional group.
• the polymerizable functional group may be an alkenyl, alkynyl, acrylate, methacrylate, maleate, fumarate or acrylamide functional group.
• the polymerizable functional group is a methacrylate.
• the R group contains the chromophore moiety. Examples of methacrylate monomers are provided below.
• the R group contains the
• chromophore moiety examples include acrylate monomers.
• the dye monomer may be a mono functional monomer or may be a multifunctional monomer.
• the dye monomer is multifunctional and more preferably di-functional.
• mono-functional monomer used in this context refers to a monomer having exactly one polymerizable functional group, such as radical polymerisation.
• multi-functional monomer used in this context refers to a monomer having two or more (i.e. more than one) polymerizable functional groups, such as radical polymerisation.
• a di-functional monomer is a type of multifunctional monomer having exactly two polymerizable functional groups, such as radical polymerisation.
• the dye monomer is an anthraquinone methacrylate, preferably an anthraquinone dimethacrylate.
• Examples of preferred dye monomers include: 3-[(9,10-dioxoanthracen-1-yl)amino]propyl
• the amount of dye monomer in the curable ink composition is 0.5 wt% or more based on the total weight of the ink composition.
• the dye monomer is present at 1.0 wt % or more based on total weight of the ink composition, preferably 2 wt% or more, and even more preferably 4 wt% or more.
• the dye monomer is present at 30 wt% or less based on total weight of the ink composition, more preferably 20 wt% or less and even more preferably 10 wt% or less.
• the dye monomer may be present in an amount that is in a range with the upper and lower limits selected from the amounts described above.
• the dye monomer may be present at 1.0 to 10 wt % based on total weight of the ink composition.
• the dye monomer has a molecular weight, such as a weight average molecular weight (Mw) greater than 100, more preferably greater than 200 and even more preferably greater than 300.
• the dye monomer has a molecular weight, such as a weight average molecular weight (Mw) less than 2000, more preferably less than 1500, and even more preferably less than 1 ,000.
• Mw weight average molecular weight
• the dye monomer may have a molecular weight, such as a weight average molecular weight (Mw) that is in a range with the upper and lower limits selected from the amounts described above.
• Mw weight average molecular weight
• the dye monomer has a molecular weight, such as a weight average molecular weight (Mw) between 100 and 2000, more preferably between 100 and 2,000, more preferably between 100 and 1 ,000, more preferably between 200 and 1 ,000 and even more preferably between 300 and 1 ,000.
• the curable ink composition contains a carrier monomer.
• the carrier monomer has at least one functional group that can undergo polymerization and is present in at 50 wt % or more based on total weight of the ink composition.
• the carrier monomer may be a single monomer or may be a combination of two or more monomers.
• the carrier monomer is a single monomer.
• the polymerizable functional group of the carrier monomer may be an alkenyl, alkynyl, acrylate, methacrylate, maleate, fumarate, an acrylamide functional group or a mixture thereof.
• the polymerizable functional group is an acrylate.
• the carrier monomer is selected to be compatible with the dye monomer. In this way, the carrier monomer and dye monomer will copolymerise.
• the carrier monomer may be mono functional or may be multifunctional.
• the carrier monomer is multifunctional and more preferably di-functional.
• each monomer is preferably multifunctional and more preferably di-functional.
• Suitable mono-functional monomers include mono-functional acrylates, mono-functional acrylamides, mono-functional vinyl compounds, mono-functional methacrylates, mono-functional allyl ethers, mono-functional maleates, mono-functional fumarates, mono-functional methacrylamides or a mixture thereof.
• Suitable monofunctional acrylates include caprolactone acrylate, cyclic trimethylolpropane formal acrylate, ethoxylated nonyl phenol acrylate, isodecyl acrylate, isooctyl acrylate, octyldecyl acrylate, alkoxylated phenol acrylate, tridecyl acrylate, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isoamylstyl acrylate, isostearyl acrylate, 2-ethylhexyl-diglycol acrylate, 2-hydroxy butyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxye
• Suitable mono-functional acrylamides include acryloyl morpholine, N-isopropyl acrylamide, N-tert-butyl acrylamide, diacetone acrylamide.
• Suitable mono-functional vinyl compounds include vinyl ethers such as ethyl vinyl ether, n- butyl vinyl ether, iso-butyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, or hydroxybutyl vinyl ether and vinyl amides such as N- vinyl caprolactam, N-vinyl pyrrolidone, N-methyl-N-vinyl acetamide, prN-vinyl imidazole.
• vinyl ethers such as ethyl vinyl ether, n- butyl vinyl ether, iso-butyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, or hydroxybutyl vinyl ether and vinyl amides such as N- vinyl caprol
• Suitable multi-functional monomers may have two or more functional groups selected from an alkenyl, alkynyl, acrylate, maleate, fumarate or acrylamide functional group.
• Suitable multi-functional acrylate monomers include hexanediol diacrylate (e.g. 1 ,6- hexanediol diacrylate), 3-methyl-1 ,5-pentanediyl diacrylate, di -trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaeryhtitol tetraacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1 ,4-butanediol diacrylate, 1 ,9-nonanediol diacrylate, neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, bis
• Suitable multi-functional vinyl monomers include 1 ,4-butanediol divinyl ether, diethyleneglycol divinyl ether, triethyleneglycol, divinyl ether, polyethyleneglycol divinyl ether, 1 ,4-cyclohexanedimethanol divinyl ether.
• the carrier monomer is a multi-functional acrylate monomer such as a
• the difunctional acrylate monomer may be dipropylene glycol diacrylate.
• each monomer is preferably a multi-functional acrylate monomer such as a difunctional acrylate monomer.
• the carrier monomer is a difunctional acrylate monomer and the dye monomer is a difunctional methacrylate monomer.
• the chromophore moiety of the dye monomer is an anthraquinone.
• the acrylate carrier monomer provides fast curing rates and is compatible with the methacrylate dye monomer. It is proposed that when acrylates and methacrylates are co-polymerised, the polymer tends to be methacrylate-rich due to the energetic preference for the growing chain-end to be methacrylate-terminated. In this way, most of the relatively small amount of the dye monomer (as compared to the amount of the carrier monomer) can be incorporated whilst maintaining fast curing rates.
• the amount of carrier monomer in the curable ink composition is 50 wt% or more based on the total weight of the ink composition.
• the carrier monomer is present at 50 wt % or more based on total weight of the ink composition, preferably 60 wt% or more, and even more preferably 70 wt% or more.
• the carrier monomer is present at 90 wt% or less based on total weight of the ink composition, more preferably 85 wt% or less and even more preferably 80 wt% or less.
• the carrier monomer may be present in an amount that is in a range with the upper and lower limits selected from the amounts described above.
• the dye monomer may be present at 60 to 80 wt % based on total weight of the ink composition.
• the carrier monomer has a molecular weight, such as a weight average molecular weight (Mw) greater than 30, more preferably greater than 50 and even more preferably greater than 100.
• Mw weight average molecular weight
• the carrier monomer has a molecular weight, such as a weight average molecular weight (Mw) less than 1000, more preferably less than 500, more preferably less than 400, and even more preferably less than 200.
• the carrier monomer may have a molecular weight, such as a weight average molecular weight (Mw) that is in a range with the upper and lower limits selected from the amounts described above.
• the carrier monomer has a molecular weight, such as a weight average molecular weight (Mw) between 30 and 1000, more preferably between 30 and 500, more preferably between 50 and 500, more preferably between 50 and 400 and even more preferably between 100 and 200.
• each monomer preferably has a molecular weight as disclosed above.
• the curable ink composition comprises an initiator.
• the initiator may be a thermal initiator of a photoinitiator, preferably the initiator is a photoinitiator.
• initiator refers to a compound that undergoes a reaction due to an external stimulus producing a reactive species such as a radical.
• the external stimulus may be UV radiation, thermal radiation, actinic radiation or the use of an electron beam.
• the reactive species reacts with one or more of the monomers to initiate the polymerization reaction.
• the initiator may be a photoinitiator.
• photoinitiator refers to a compounds that undergoes a photoreaction on absorption of light, producing reactive species such as a radical.
• the external stimulus may be visible light or UV radiation, preferably the external stimulus is UV radiation.
• the reactive species produced reacts with one or more of the monomers to initiate the polymerization reaction.
• the photoinitiator may provide this function when irradiated with light having a wavelength within the range of 450 to 300 nm (i.e. UV radiation). This may mean that the photoinitiator has light absorption characteristics in the entire wavelength range of 450 to 300 nm.
• the photoinitiaotor may be chosen to absorb light at a frequency that the chromophore does not absorb light.
• phosphine oxides have absorption peak at around 360 to 400 nm. Red anthraquinone chromophores have absorption minima in this range. In this way, the chromophore moiety does not absorb the radiation that is applied to initiate the reaction.
• Photoinitiators are well known in the art.
• the photoinitiator may be selected from benzil ketals, a-hydroxyalkyphenones (such as a-hydroxyacetophenones, for example, difunctional alpha hydroxyl ketone or 2-hydroxy- 1-[4-[[4-(2-hydroxy-2-methyl- propanoyl)phenyl]methyl]phenyl]-2-methyl-propan-1-one, discussed below), a--amino acetophenones, phosphine oxides (such as TPO), benzophenones, ketosulphones, thioxanthones, benzoylformate esters or a mixture thereof.
• the photoinitiator is selected from TPO and benzophenone. More preferably, the photoinitiator is a mixture of TPO and benzophenone.
• the total amount of the photoinitiator is 30 wt % or less based on total weight of the ink composition, more preferably 20 wt % or less and even more preferably 17 wt % or less.
• the total amount of the photoinitiator is 5 wt % or more based on total weight of the ink composition, preferably 8 wt % or more, and even more preferably 10 wt % or more.
• the total amount of the photoinitiator may be an amount that is in a range with the upper and lower limits selected from the amounts described above.
• the total amount of the photoinitiator is 10 to 20 wt % based on total weight of the ink composition.
• the inks of the present invention may comprise a solvent such as an organic solvent.
• the dye monomer may be fully solubilised in the curable ink composition.
• the organic solvent may be selected from dichloromethane (DCM), acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, cyclohexanone, ethanol, isopropanol, n-propanol, isobutanol, n-butanol, sec-butanol, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, n-amyl acetate, isoamyl acetate, isobutyl isobutyrate, ethylene glycol, propylene glycol, 1-methoxy-2- propanol and 1-methoxy-2-propyl acetate, dimethyl carbonate, propylene carbonate, dimethyl succinate, dimethyl glutarate, dimethyl adip
• the solvent may be present in less than 95 wt % based on total weight of the ink composition, more preferably less than 80 wt % and even more preferably less than 60 wt %.
• the solvent is present in greater than 10 wt % based on total weight of the ink composition, preferably greater than 30 wt %, and even more preferably greater than 50 wt %.
• the solvent may be present in an amount that is in a range with the upper and lower limits selected from the amounts described above.
• the inks of the present invention are for CIJ or TIJ printing, the inks have solvent amounts as described above.
• water may be present at 10 wt % or less based on the total weight of the ink composition, and preferably water is present at 5 wt % or less and even more preferably 1 wt% or less based on the total weight of the ink composition.
• inks of the invention are substantially free from volatile organic solvents and water.
• the inks of the invention are for drop on demand inkjet printing such as piezoelectric drop on demand inkjet printing the inks are preferably free from volatile organic solvents and water.
• the solvent may be present at less than 20 wt % based on total weight of the ink
• the solvent is present at greater than 1 wt% based on total weight of the ink composition, preferably greater than 3 wt%, and even more preferably greater than 4 wt%.
• the solvent may be present at an amount that is in a range with the upper and lower limits selected from the amounts described above.
• the inks of the invention are for drop on demand inkjet printing such as piezoelectric drop on demand inkjet printing the inks have solvent amounts as described above.
• the inks of the present invention may further comprise an amine compound.
• the inks of the current formulation may have low viscosity, for example, to increase compatibility with drop on demand printers such as piezoelectric drop on demand printer.
• Low viscosity formulations are particularly susceptible to oxygen inhibition because the oxygen can diffuse more rapidly into the printed film.
• the presence of oxygen interferes with the proper propagation of the free radical reactions so that cure may not be complete, particularly on the surface of the ink after exposure to UV light.
• amines provide a source of abstractable hydrogen atoms to quench reactive oxygen species. It is also proposed that amines recycle the peroxy radicals that are formed as a consequence of reaction with oxygen. This means that the radicals are not lost to the system, but are returned, via the amine, in a form that can support further
• amine compounds in particular oligomeric amine compounds, contribute positively to the toughness and adhesion of the cured ink film.
• the amine compound may be any type of amine containing compound such as a small molecule amine, an amine functional oligomer or an amine functional polymer.
• the amine may be a primary, secondary or tertiary amine.
• a primary amine is an amines having one non-hydrogen substituent (i.e. NRH2); a secondary amine is an amide having two non-hydrogen substituents (i.e. NRR’H); a tertiary amine is an amine having three non-hydrogen substituents (i.e. NRR’R”).
• the amine is a secondary or tertiary amine, more preferably a tertiary amine.
• the amine compound is an amine acrylate or an amine oligomer.
• the amine acrylate is an amine functional acrylate oligomer.
• amine functional acrylates include aminated polyether acrylate oligomers (such as Ebecryl 7100 and Ebecryl LEO10552).
• amine oligomers include Genomer 5695 and Genomer 5275.
• the amine compound has a molecular weight, such as a weight average molecular weight (Mw) between 200 and 10,000, more preferably between 200 and 5,000, more preferably between 500 and 5,000, more preferably between 200 and 1 ,000 and even more preferably between 500 and 1 ,000.
• Mw weight average molecular weight
• the amine compound is present in less than 25 wt% based on total weight of the ink composition, more preferably less than 15 wt% and even more preferably less than 10 wt%.
• the amine compound is present in greater than 1 wt% based on total weight of the ink composition, preferably greater than 2 wt%, and even more preferably greater than 5 wt%.
• the amine compound may be present in an amount that is in a range with the upper and lower limits selected from the amounts described above.
• the ink composition and the printed deposit may comprise a further colourant.
• the further colourant is not particularly limited and any suitable colourant known in the art may be used.
• incorporation of a further colourant may provide additional properties to the ink, for example the incorporation of a white further colourant may provide opaque films.
• the further colourant may be a dye or a pigment.
• the further colourant is a pigment.
• the pigment may be an inorganic or an organic pigment.
• the pigment has an average particle size of less than 1 pm.
• the average particle size referred to here is the Z average particle size calculated using dynamic light scattering. This is the intensity weighted mean hydrodynamic size of the collection of particles.
• the organic pigments may be selected from azo pigments (including azo lake, insoluble azo pigment, condensed azo pigment, and chelate azo pigment), polycyclic pigments (for example, phthalocyanine , perylene, perinone, anthraquinone, quinacridone , dioxazine, thioindigo, isoindolinone, and quinophthalone pigments), dye-type chelate pigment (for example, basic dye-type chelate pigments and acid dye-type chelate pigment), nitro pigments, nitroso pigments, aniline black and carbon black.
• azo pigments including azo lake, insoluble azo pigment, condensed azo pigment, and chelate azo pigment
• polycyclic pigments for example, phthalocyan
• Carbon blacks for use in the ink of the present invention include carbon blacks manufactured by Mitsubishi Chemical Corporation, for example, No. 2300, No. 900, MCF 88, No. 33, No. 40, No. 45, No.52, MA 7, MA 8, MA 100, and No. 2200 B; carbon blacks manufactured by Columbian Carbon Co., Ltd., for example, Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, and Raven 700; carbon blacks manufactured by Cabot Corporation, for example, Regal 400 R, Regal 330 R, Regal 660 R, Mogul L, Mogul E, Monarch 700,
• Color Black S 150 Color Black S 160, Color Black S 170, Printex 35, Printex U, Printex V, Printex 140 U, Special Black 6, Special Black 5, Special Black 4A, and Special Black 4.
• Pigments for yellow inks include C.l. Pigment Yellow 1 , C.l. Pigment Yellow 2, C.l. Pigment Yellow 3, C.l. Pigment Yellow 12, C.l. Pigment Yellow 13, C.l. Pigment Yellow 14, C.l.
• Pigment Yellow 16 C.l. Pigment Yellow 17, C.l. Pigment Yellow 73, C.l. Pigment Yellow 74, C.l. Pigment Yellow 75, C.l. Pigment Yellow 83, C.l. Pigment Yellow 93, C.l. Pigment Yellow 95, C.l. Pigment Yellow 97, C.l. Pigment yellow 98, C.l. Pigment Yellow 109, C.l. Pigment Yellow 110, C.l. Pigment Yellow 114, C.l. Pigment Yellow 128, C.l. Pigment Yellow 129, C.l. Pigment yellow 138, C.l. Pigment Yellow 150, C.l. Pigment Yellow 151 , C.l. Pigment Yellow 154, C.l. Pigment Yellow 155, C.l. Pigment Yellow 180, C.l. Pigment Yellow 185, and C.l. Pigment Yellow 139.
• Pigments for orange inks include C.l. Pigment Orange 64, and C.l. Pigment Orange 73.
• Pigments for magenta inks include C.l. Pigment Red 5, C.l. Pigment Red 7, C.l. Pigment Red 12, C.l. Pigment Red 48 (Ca), C.l. Pigment Red 48 8 (Mn), C.l. Pigment Red 57 (Ca), C.l. Pigment Red 57 : 1 , C.l. pigment Red 112, C.l. Pigment Red 122, C.l. Pigment Red 123, C.l. Pigment Red 168, C.l. Pigment Red 184, C.l. Pigment Red 202, C.l. Pigment Red 176, C.l. Pigment Red 254, C.l. Pigment Red 255, C.l. Pigment Red 272, C.l. Pigment Red 254, C.l Pigment Violet 19.
• Pigments for cyan inks include C.l. Pigment Blue 1 , C.l. Pigment Blue 2, C.l. Pigment Blue 3, C.l. Pigment Blue 15 : 2, C.l. Pigment Blue 15:3, C.l. Pigment Blue 15:4, C.l. Pigment Blue 15 : 34, C.l. Pigment Blue 16, C.l. Pigment Blue 22, C.l. Pigment Blue 60, C.l. Vat Blue 4,
• C.l . Vat Blue 60 Pigments for green inks include C.l. Pigment Green 3 and C.l Pigment Green 7.
• Pigments for violet inks include C.l. Pigment Violet 23 and C.l. Pigment Violet 37.
• Pigments for white inks include C.l. Pigment White 6.
• the organic pigment is selected from C.l. Pigment Yellow 83, C.l. Pigment Yellow 138, C.l. Pigment Yellow 139, C.l. Pigment Yellow 150, C.l. Pigment Yellow 151 , Pigment Yellow 154, C.l. Pigment Yellow 155, C.l. Pigment Yellow 185, C.l. Pigment Orange 43, Pigment Orange 64, C.l. Pigment Orange 73, C.l. Pigment Red 122, C.l. Pigment Red 176, C.l. Pigment Red 254, C.l. Pigment Red 255, C.l. Pigment Red 272, C.l. Pigment Blue 15:3, C.l. Pigment Blue 15:4, C.l. Pigment Green 7, C.l. Pigment Violet 19, C.l. Pigment Violet 23, Pigment Black 7, and carbon black.
• the pigment may be in the form of a dispersion in the composition.
• the pigment dispersion may comprise a dispersant or one or more of the monomer components that is present in the ink.
• the further colorant may be an oil or solvent soluble dye.
• yellow dyes examples include aryl or heteryl azo dyes having a coupling component such as a phenol, a naphthol, an aniline, a pyrazolone, a pyridone, or an open-chain active methylene compound; azomethine dyes having a coupling component such as an open- chain active methylene compound; methine dyes such as benzylidene dyes and
• monomethineoxonol dyes such as naphthoquinone dyes and anthraquinone dyes
• quinone dyes such as naphthoquinone dyes and anthraquinone dyes
• other dye species such as quinophthalone dyes, nitro/nitroso dyes, acridine dyes, and acridinone dyes.
• magenta dyes examples include aryl or heteryl azo dyes having a coupling component such as a phenol, a naphthol, or an aniline; azomethine dyes having a coupling component such as a pyrazolone or a pyrazolotriazole; methine dyes such as arylidene dyes, styryl dyes, merocyanine dyes, and oxonol dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, and xanthene dyes; quinone dyes such as naphthoquinones, anthraquinones, or anthrapyridones; and condensed polycyclic dyes such as dioxazine dyes.
• aryl or heteryl azo dyes having a coupling component such as a phenol, a naphthol, or an aniline
• cyan dyes examples include indoaniline dyes, indophenol dyes, and azomethine dyes having a coupling component such as a pyrrolotriazole; polymethine dyes such as cyanine dyes, oxonol dyes, and merocyanine dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, and xanthene dyes; phthalocyanine dyes; anthraquinone dyes; aryl or heteryl azo dyes having a coupling component such as a phenol, a naphthol, or an aniline; and indigo/thioindigo dyes.
• the further colourant is present in between 1 to 25 wt% based on total weight of the ink composition, more preferably 1.5 to 15 wt%, and most preferably 2 to 8 wt% based on total weight of the ink composition.
• the further colourant is present in less than 25 wt% based on total weight of the ink composition, more preferably less than 15 wt% and even more preferably less than 10 wt%.
• the further colourant is present in greater than 1 wt% based on total weight of the ink composition, preferably greater than 1.5 wt%, and even more preferably greater than 2 wt%.
• the further colourant may be present in an amount that is in a range with the upper and lower limits selected from the amounts described above.
• the curable ink composition of the invention may further comprise an oligomer.
• the oligomer is polymerizable. That is, the oligomer contains functional groups that can undergo polymerization. Preferably, the oligomer is UV curable.
• the cure of the ink may be improved.
• Suitable UV curable oligomers for use in the inks of the invention include urethane acrylates, polyester acrylates, polyether acrylates, epoxy acrylates and acrylic acrylates.
• the oligomer is a polyether acrylate such as an aminated polyether acrylate (e.g. Ebecryl Leo 10552).
• an aminated polyether acrylate e.g. Ebecryl Leo 10552
• animated polyether acrylates the same compounds provides both an oligomer and an amine compound to the ink composition.
• the oligomer has a molecular weight, such as a weight average molecular weight (Mw), of 200 to 50,000, more preferably 300 to 5,000, more preferably 500 to 3,000 and even more preferably 500 to 2,000.
• Mw weight average molecular weight
• the oligomer is present in less than 25 wt% based on total weight of the ink composition, more preferably less than 15 wt% and even more preferably less than 10 wt%.
• the oligomer is present in greater than 1 wt% based on total weight of the ink composition, preferably greater than 2 wt%, and even more preferably greater than 5 wt%.
• the oligomer may be present in an amount that is in a range with the upper and lower limits selected from the amounts described above.
• the present disclosure provides a method for printing markings on a substrate.
• the curable ink compositions of the invention may be printed using an inkjet printer, the method comprising the steps of directing a stream of droplets of the ink composition to a substrate and curing the printed ink composition for example by treating the printed ink composition to UV radiation.
• the ink compositions are formulated by combining the components using methods known in the art.
• the curing process may be carried out by the application of thermal radiation, actinic radiation, by the use of an electron beam or by treating the printed ink composition to UV radiation.
• the curing process is carried out by treating the printed ink composition to UV radiation.
• the inkjet printer may be a thermal inkjet printer (i.e. a TIJ printer), a continuous inkjet printer (i.e. a CIJ printer) or a drop on demand inkjet printer (i.e. a DOD printer).
• a thermal inkjet printer i.e. a TIJ printer
• a continuous inkjet printer i.e. a CIJ printer
• a drop on demand inkjet printer i.e. a DOD printer
• the inkjet printer is a drop on demand inkjet printer, such as a piezo electric drop on demand inkjet printer.
• the inks are applied to the substrate using a high resolution drop on demand printer capable of emitting a range of droplet sizes below 20 pi volume.
• the inks of the current invention are cured.
• the curing process promotes the polymerization of the monomers in the ink composition to provide a printed deposit.
• the curing process is initiated by the initiator.
• the curing process may be a UV curing process.
• the initiator is a UV curing process.
• the UV curing process may comprise a single application of UV radiation or multiple applications of UV radiation. In some cases, the UV curing process comprises two applications of UV radiation.
• the first (or only) application of UV radiation is provided by an LED.
• the LED preferably emits within the range 365 nm and 405 nm.
• the first application of UV radiation provides a dose of 395 nm light delivered at from 20 to 500 mJ/cm 2 , and more preferably at from 50 to 200 mJ/cm 2 (measured as UVA2 using an EIT Power Puck).
• the first application of UV radiation occurs immediately after printing, for example using an LED positioned immediately adjacent to the print head.
• the ink is at least partially cured immediately after printing and further spreading of the ink across the substrate is prevented.
• the first application of UV radiation is sufficient to cure the ink.
• UV radiation In other cases, additional applications of UV radiation are required. This is particularly the case at high printing speeds for example print speed print speeds up to 50 m/min, more preferably 75 m/min.
• the additional application of UV radiation is preferably provided by a mercury arc source.
• the dose of U VA is preferably from 30 to 1000m J/cm 2 and more preferably from 50 to 300m J/cm 2+ (measured with an EIT Power Map).
• printing is carried out using a multi-pass inkjet printer.
• a UV light source preferably an LED, is mounted on the printhead carriage. In this way, the UV light may be applied after each successive row of printing.
• the present disclosure provides a method for printing markings on a substrate. Any suitable substrate may be printed in accordance with the invention.
• suitable substrates include porous substrates such as uncoated paper, semi- porous substrates such as aqueous coated paper, clay coated paper, silica coated paper,
• UV overcoated paper, polymer overcoated paper, and varnish overcoated paper, and non- porous substrates such as hard plastics, polymer films, polymer laminates, metals, metal foil laminates, glass, and ceramics.
• the paper substrates may be thin sheets of paper, rolls of paper, or cardboard.
• Plastics, laminates, metals, glass, and ceramic substrates may be in any suitable form such as in the form of bottles or containers, plates, rods, cylinders, etc.
• the curable ink composition of the present invention is particularly suitable for printing on non-porous material, for example, non-porous materials used for food packaging.
• the substrate will be a plastic film, paper or paperboard.
• plastic films include films comprising polyethylene, polypropylene, polyester, polyamide, PVC, polylactic acid, or cellulosic films.
• the plastic film may be pretreated or coated, for example to improve the adhesion of the inks or to render it more suitable for the application in question.
• Metallic films such as those used for lidding applications, glass and ceramics may also be printed.
• compositions and methods described herein overcomes and/or mitigates at least some of the problems described above, providing an improved quality print.
• the curable ink composition and/or the printed deposit may contain additional components, such as are common in the art (see for example EP2070998 and EP1788045).
• the ink composition and/or the printed deposit may further comprise one or more stabilisers (e.g. photostabilizers), preservatives (e.g. antioxidants, anti-aging agents), humectants, surfactants, conductivity salts, wetting agents, surface treatment agents, adhesion promotion additives, dispersants, tackifiers, biocides, antiseptics, crosslinking promoters,
• stabilisers e.g. photostabilizers
• preservatives e.g. antioxidants, anti-aging agents
• humectants e.g. surfactants, conductivity salts, wetting agents, surface treatment agents, adhesion promotion additives, dispersants, tackifiers, biocides, antiseptics, crosslinking promoters,
• the ink composition further comprises one or more stabilisers (e.g. photostabilizers), conductivity salts or wetting agents.
• stabilisers e.g. photostabilizers
• conductivity salts or wetting agents e.g. photostabilizers
• the ink composition and/or the printed deposit further comprises a stabiliser.
• the jetting performance of an inkjet ink is dependent on its viscosity.
• Undesired free radical polymerisation for example of the acrylate or vinyl ether groups, can lead to a viscosity increase.
• a stabiliser may be used to prevent undesired free radical polymerisation, for example the stabiliser may acts as a polymerisation inhibitor to avoid even low levels of free radical polymerisation in the ink during storage or before use.
• Suitable stabilisers include p-methoxy phenol (MEHQ), butylated hydroxy toluene (BHT), quinone methide, cupferron-AI, and TEMPO.
• a stabiliser is present at from 0.1 to 5 wt % based on total weight of the ink composition.
• the ink composition and/or the printed deposit may further comprise a conductivity additive.
• the conductivity additive may be any organic salt known in the art.
• Conductivity additives for ink compositions are well-known in the art.
• the organic salt is selected from quaternary ammonium or phosphonium salts.
• the organic salt may be selected from tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium acetate, tetrabutylammonium nitrate, tetrabutylammonium
• a conductivity additive is present at from 0.1 to 5 wt % based on total weight of the ink composition.
• the ink composition and/or the printed deposit may further comprise a wetting agent.
• wetting agents for ink compositions are well-known in the art.
• the wetting agent may be a silicone based wetting agent, for example a silicone polyether acrylate wetting agent such as TEGO Rad 2300.
• a wetting agent is present at from 0.1 to 5 wt % based on total weight of the ink composition, more preferably at from 1 to 2 wt% based on the total weight of the ink composition.
• the ink composition and/or the printed deposit may further comprise a humectant.
• Suitable humectants include ethylene glycol, 1 ,3-propanediol, 1 ,4-butanediol,
• the ink composition may comprise approximately a 1 :1 ratio of humectant to solvent.
• the ink composition may comprise up to 30 wt% of humectants in total based on the total weight of the composition. More preferably, the ink composition comprises up to 20wt% of humectants in total based on the total weight of the composition.
• the ink composition and/or the printed deposit may further comprise a preservative.
• the preservative may be an antioxidant or an anti-aging agent.
• Suitable preservatives include sodium benzoate, benzoic acid, sorbic acid, potassium sorbate, calcium sorbate, calcium benzoate, methylparaben and mixtures of two or more thereof.
• the ink composition may comprise up to 2wt% of preservative based on the total weight of the composition. More preferably, the ink composition comprises up to 1wt% of preservative based on the total weight of the composition.
• the ink composition and/or the printed deposit may further comprise a surfactant.
• Suitable surfactants include anionic, cationic or non-ionic surfactants and mixtures of two or more thereof.
• anionic surfactants include alkyl sulphate, alkylaryl sulfonate, dialkyl sulfonate, dialkyl sulphosuccinate, alkyl phosphate and polyoxyethylene alkyl ether sulphate.
• Non-limiting examples of cationic surfactants include alkylamine salt, ammonium salt, alkylpyridinium salt and alkylimidazolium salt.
• Non-limiting examples of non ionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerine fatty acid ester, a fluorine-containing non-ionic surfactant and a silicon-containing non-ionic surfactant. Mixtures of two or more surfactants may be used.
• the ink composition may comprise up to 5wt% of surfactant based on the total weight of the composition. More preferably, the ink composition comprises up to 1 wt% of surfactant based on the total weight of the composition.
• the ink composition and the printed deposit may further comprise a tackifier.
• the tackifier may be a binder; preferably, when the tackifier is a binder it is used in combination with a co-binder.
• the tackifier is a non-film forming polymer.
• the tackifier may be used in combination with other polymers to produce the desired properties.
• Suitable tackifiers include resins such as rosins, terpenes and modified terpenes, aliphatic, cycloaliphatic and aromatic resins, terpene phenolic resins and silicone or mineral oils.
• the tackifiers are a terpene phenolic resin and/or an ester of hydrogenated rosin.
• the ink composition may comprise from 0.3 to 10 wt% of tackifier based on the total weight of the composition. More preferably, the ink composition comprises from 1 to 5 wt% of tackifier based on the total weight of the composition.
• the ink composition and the printed deposit may further comprise an adhesion promoter.
• An adhesion promotor is a substance which acts to promote adhesion of the ink composition to a substrate.
• Suitable adhesion promotors are titanium phosphate complex, titanium acetylacetonate, triethanolamine zirconate, zirconium citrate, zirconium propanoate, organosilicon, polyketones binders, polyesters binders, or a ketone condensation resin.
• the ink composition and the printed deposit may further comprise a pigment dispersant.
• a dispersant is a substance which promotes dispersion of a component of the ink composition, for examples promotes dispersion of a pigment.
• Suitable dispersants include ionic and non-ionic dispersants.
• the dispersant is an acrylic block co-copolymer.
• the dispersant may be pre-mixed with the colourant for example the pigment.
• the dispersant may be selected according to the nature of the colourant.
• the amount of dispersant is preferably from 2 wt% to 200 wt% based on the weight of pigment in the ink composition. Definitions
• the term printed deposit refers to the ink composition after it has been printed onto a suitable substrate and cured. That is the ink composition of the present invention wherein at least some of the monomers present in the ink composition are polymerized to form a film.
• ink composition includes an ink composition suitable for use in any kind of printing, for example in inkjet printing.
• the ink composition is typically in the form of a liquid.
• polymer refers to any substance having a repeat unit.
• 1-chloroanthraquinone, 1 ,5-anthraquinone, and 1 ,8-anthraquinone were purchased from Tokyo Chemical Industry.
• Propanolamine and methacryloyl chloride were purchased from Sigma-Aldrich.
• UV-vis spectroscopy was carried out using a Shimadzu UV-1800 spectrophotometer, using the appropriate solvent as a reference.
• NMR spectra were obtained using a 500 MHz DCH Cryoprobe Spectrometer.
• Viscosity of solutions were measured using a Brookfield DV-E viscometer, at 25°C and with a spindle speed of 60 rpm.
• Curing of acrylate/methacrylate films was carried out by placing the uncured samples on a 2m slide underneath a Robinson iron-doped mercury arc lamp (model CA300) and a Phoseon 20 W/cm 2 LED lamp at 395nm (model FP300 225X20WC395). Standard curing conditions used were 60% Arc lamp and 50% LED, with the slide passing under the lamps once at a speed of 50 m/min. These curing conditions deliver a UVA dose of about 175mJ/cm 2 . Ageing studies were carried out using a Bandol Wheel (Unitronics Vision 120) at 50°C for the times indicated in the text.
• Methacryloyl chloride (1 ml, 10.3 mmol) was added dropwise over 30 min and the mixture stirred for 30 min at 0°C, then overnight at room temperature. The mixture was then taken up into water to precipitate the product, which was separated by filtration and recrystallised from methanol.
• the methacrylate-functionalised dye compounds 1a to 5a were dissolved in a carrier monomer and optionally a further solvent.
• DPGDA Dipropylene Glycol Diacrylate
• Ink solutions of the invention were prepared by combining the stock solution with compounds 1a, 3a, 4a or 5a. These will be referred to as solutions 1a, 3a, 4a and 5a respectively
• Comparative solutions were made using the hydroxylated anthraquinone compounds 1 , 3, 4 and 5 referred to as comparative solution 1 , 3, 4, and 5 respectively.
• Compounds 4 and 5 were dissolved in DPGDA at 5 wt%.
• Compounds 1 and 3 were dissolved in DPGDA at 5 wt% with 5 wt% of dichloromethane.
• a further comparative solution was produced by dissolving Methacrylated anthraquinone 4a in DCM. This solution will be referred to as comparative solution 4-1.
• the composition of the solution was 2 wt% compound 4a, 10 wt% Omnirad TPO, and 5 wt% benzoquinone, dissolved in DCM.
• Films of the solutions 1a, 3a, 4a and 5a produced in Example 2 were prepared on a coated substrate (Sheen card). These films were subsequently irradiated by UV. Curing of films was carried out by placing the uncured samples on a 2m slider underneath a Robinson iron- doped mercury arc lamp (model CA300) and a Phoseon 20 W/cm 2 LED lamp at 395nm (model FP300 225X20WC395). For standard curing conditions the arc lamp was set to 60% and the LED lamp set to 50%, with the slider passing under the lamps once at a speed of 50 m/min. These curing conditions deliver a UVA dose of about 175 mJ/cm 2 .
• the first and second rows of photographs in Figure 4(a) show the colours of these films before and after UV irradiation respectively.
• the methacrylated dyes do change during this curing process, but they remain deeply coloured.
• the third and fourth rows of photographs in Figure 4(a) show films of comparative solution 1 , 3, 4 and 5 before and after UV curing respectively. These films have lost most of their colour, becoming brown in most cases. It is proposed that binding to a polymer network stabilises the dye.
• the results for comparative example 4-1 is shown in Figure 4(b).
• the first row shows films of comparative solution 4-1 before UV curing.
• the second row shows films of comparative solution 4-1 after UV curing.
• the left column shows a film printed on uncoated porous card and the right column shows a film coated on sheen (shiny) card.
• the colour of the film after UV curing is considerably more brown than the films produced using solution 4a after UV curing.
• the film on the sheen card exhibits increased tackiness compared to any of the films produced using solutions 1a, 3a, 4a and 5a.
• the CIELAB space was originally designed to correspond to perceptual uniformity (i.e. a change in the CIELAB co-ordinates is directly correlated to a visually perceived change).
• Each pair,“(i)” and“(ii)”, of values in the table (and in Figure 5) represents the change during irradiation, for solution 1 a, 3a, 4a and 5a and comparative solutions 1 , 3, 4 and 5. It is clear from these data that the change in colour is much larger for the hydroxyl-functionalised dyes (comparative solution 1 , 3, 4 and 5), indicating that these dyes are degrading faster under UV irradiation.
• the cured films were placed in a Bandol Wheel at 50°C; this instrument is designed to accelerate the aging of the samples, by subjecting them to a dose of ultraviolet equivalent to approx. 2x the natural UV from the sun.
• Figure 6 describes the changing DE value for each film as the aging time of the film increases.
• “Line 1a” refers to the films produced using solution 1a
• “line 1” refers to the films produced using comparative solution 1 and so on. In all cases other than 5/5a, the films containing hydroxylated dye continue to increase DE more rapidly than the films containing methacrylated dye.
• the cured films were soaked in solvents in order to test whether the colour leaches out of the cured film.
• An uncoated sheen card was coated with a film produced by curing a solution containing the hydroxylated dye 4 (i.e. comparative solution 4).
• a film produced by curing a solution containing the hydroxylated dye 4 i.e. comparative solution 4
• Four 1cm 2 pieces of this film-coated substrate were cut and cured for the same times as for the methacrylated films (curing time increasing from e-h; film e was passed under the lamps once, film f twice, film g three times, and film h four times). In this case, the colour of the film turns brown during curing.
• Each of the four pieces was soaked in 5 ml acetone for 24h in a separate container.
• the acetone used for soaking became a bright pink colour in each case.
• the methacrylated dye film is relatively stable under UV curing while the hydroxylated dye films quickly become brown.
• the dye leaching out of the hydroxylated dye films remains pink; we suggest that the brown colouration may be a surface degradation effect, leaving enough pink dye in the film for the soaking liquid to be coloured. Similar results were obtained when the soaking liquid was dichloromethane.
• Figure 7 shows the effect of soaking on the two coated substrates. From the images, it can be clearly seen that the colour of the cured film changes significantly more for the hydroxylated films during curing than for the corresponding methacrylated films. Additionally, the dye leaches out of the films containing hydroxylated dye significantly more readily than those containing methacrylated dye. From these results it seems that the methacrylated dye is strongly bound into the cured film.
• the viscosity of the stock solution produced in Example 2 was measured at 11.5 mPa.S at 25°C.
• compositions of the invention were produced by combining 1 wt% and 5 wt% respectively of compound 4a with the stock solution.
• the viscosity of each of the compositions of the invention was measured at 25 °C to be 11.3 mPa.S (1 wt% of 4a) and 11.7 mPa.S (4 wt% of 4a), respectively.
• a Fujifilm Dimatix inkjet (Model number DMP-2831) printer was used to print a logo from a solution containing 2% w/w of 4a dissolved in the stock solution described Example 2.
• Figure 8 (a) is a photograph of the resulting logo, printed on paper;
• Figure 8 (b) shows the same logo after exposure to UV irradiation.
• the image quality and cure of the printed deposit is good.
• the ink did not visibly run when a drop of MEK was applied.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Ink Jet Recording Methods And Recording Media Thereof (AREA)
• Ink Jet (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=66380497

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (1)

Citations (7)

Family Cites Families (17)

• 2019
  • 2019-03-08 GB GB1903147.5A patent/GB2582017B/en active Active
• 2020
  • 2020-03-06 JP JP2021553400A patent/JP7682794B2/ja active Active
  • 2020-03-06 WO PCT/EP2020/055969 patent/WO2020182640A1/en not_active Ceased
  • 2020-03-06 EP EP20709566.2A patent/EP3935111B1/en active Active
  • 2020-03-06 US US17/437,378 patent/US12071556B2/en active Active

Patent Citations (8)

Non-Patent Citations (4)

Also Published As

Similar Documents

Legal Events