CA2247003A1 - Water-based coatings - Google Patents
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- CA2247003A1 CA2247003A1 CA 2247003 CA2247003A CA2247003A1 CA 2247003 A1 CA2247003 A1 CA 2247003A1 CA 2247003 CA2247003 CA 2247003 CA 2247003 A CA2247003 A CA 2247003A CA 2247003 A1 CA2247003 A1 CA 2247003A1
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Abstract
The invention relates to novel water-based surface and lamination coating compositions and to their use as surface printing inks for printing onto substrates and in particular for printing or coating onto plastic substrates. The surface printing inks of the present invention are superior in printing aptitude and adhesion.
Description
~ ' ,~
WATER-BASED COATIN'-,S
This invention relates to water-borne coatings, s including inks, their composition and their use as surface and lamination coatings on paper and plastic substrates such as polyolefin, polyester, and poiyamide.
A growing area in the field of printing is known as flexography or flexographic ink printing. Flexographic o ink printing is a branch of rotary typographic printing in which the pr_nting is applied to a print-receiving substrate by use of a flexible relief plate with highly fluid, volat~le inks which dry rapidly by evaporation.
Flexography s widely utilized for printing on plastic films. Another process which is widely utilized for printing on plastic films is the gravure process. In this process the printing image is engraved into a cylinder in the form of cells which become filled with ink. Printing is achieved b~ passing the substrate between the gravure cylinder and an impression roller under pressure.
A flexographic or gravure printing ink generally contains three basic types of ingredients denominated as a solvent, a colorant, and a binder. Minor amounts of other additives also may be employed to provide the desired 2s characteristics (such as rheology, viscosity, printability) for the printing ink ccmposition.
Liquid printing inks dry by solvent evaporation, usually with heat or air blower assistance. Solvent systems may be either water systems which use water as a partial or total solvent, or systems using volatile organic solvents. Primary organic sclvents are usually ~, .
alcohols, thou3h some contain other o~genated solvents.
In recent years, increased emphasis has been placed on the use of water as the solvent, rather than an organic solvent. In keeping with this trend, a wide variety of colorants or pigments have been developed for use in water-based ink formulations.
The binder component of the printing ink composition generally comprises a resin which functions primarily to increase adhesion of the pigment to the o substrate, while also often acting as a dispersing medium and carrier. Specific acrylic polyme:r latexes are commonly employed as binders in -~ater-based printing ink compositions. For example, U.S. Patent 4,980,408 discloses water-based printing i~ks wherein the binder is based on an acrylated rosin modified polyamide resin and a latex resin. U.S. Patent 5,498,661 discloses aqueous inks wherein the binder is prepared by emulsion polymerizing a monomer mixture which contains variou, acrylates.
However, one of the major shortcomings of using water-based inks (relative to the traditional solvent-based alternatives) for printing on plastic film is a lack of adhesion of the ink film. That is, the acrylic binders used in water-based inks do not -eadily adhere to low surface energy plastic substrates. Therefore, the ink films tend to lose their adherence to plastic films, thereby making the ink smear or run. Thus, good adhesion to plastic substrates is a highly desired characteristic because of the handling that many printed packages receive.
Therefore, it would be desira~)le to have aqueous emulsion binders for use in preparing water-based printing inks which, when utilized for printing on plastic films, ~" . ,., ~ ,, , .. , .. ,, .. , " .. ,.,., .. ", .. . .
~ ' ~, .
exhibit increased adhesion. Heretofore/ emulsified polyolefin resins have not been employed in aqueous coatings, including inks, as the binder.
The present invention is directed to novel water-based coating compositions comprising an emulsifiedpolyolefin resin, preferably a substantially linear olefin interpolymer, as the binder. The invention also includes surface printing inks comprising such a binder. The inks and coatings of the present invention are superior in o printing aptitude and adhesion to plastic surfaces.
The aqueous ink of the invention comprises a solvent, a colorant, a binder, and other materials common to ink formulations.
In the aqueous compositions of the invention, the solvent is primarily water, that is, the solvent can be water alone or can be water with mincr amounts of solvent additives such as low molecular weight alcohols, as is well known in the art.
A colorant is any material which gives color to the ink, including, for example, pigmentC and dyes. Colorants are widely available commercially and are well known to those skilled in the art.
The binder resin is an essential ingredient in the ink formulation and promotes pigment binding, good adhesion, clean printing, and excellent film wetting. The binder is employed in an amount sufficient to bind the colorant and provide adhesion to the substrate.
Preferably, the a~ueous ink or coating of the invention comprises from 40 to 80 percent by weight binder based on 30 the solids content of the ink. More preferably, the aqueous ink or coating of the invention comprises from 50 to 70 percent by weight binder based on the solids content of the ink. The solids in the colorant and additives comprise the balance of the solids in the ink or coating composition. The binder may comprise mixtures or blends of polyolefin resins. Preferably, the average particle size of the particles in the binder is not more than 2 microns, more preferably is not more than 1.5 microns and most preferably is not more than 0.5 micron. Preferably, o the average particle size of the particles in the binder is at least 0.3 micron, more preferab]y is at least 0.1 micron and most preferably is at least: 0.05 micron.
The binders of invention comprise at least one homogeneous ethylene/a-olefin interpo:Lymer which is an interpolymer of ethylene and at ;east one C3-C20 a-olefin.
The term "interpolymer" is used herein to indicate a copolymer, or a terpolymer, or a higher order polymer.
That is, at least one other comonomer is polymerized with ethylene to make the interpolymer. The term "substantially linear olefin interpolymerU as used herein means the polymers disclosed in U.S. :?atent 5,665,800 (Lai et al.).
Preferred olefinic polymers include homogeneously branched, linear ethylene/a-olefin copolymers such as TAFMER~ (a trademark of Mitsui PetroChemicals Company Limited) and EXACT~M (a trademark of Exxon Chemical Company), which can be prepared as de,cribed in U.S.
Patent 3,645,992, homogeneously branched, substantially linear ethylene/a-olefin polymers suc:h as AFFINIT~M
polyolefin plastomers (trademark of The Dow Chemical Company) and ENGAGE~ polyolefin elastomers (trademark of DuPont Dow Elastomers) which can be prepared, for example, by a process disclosed in U.S. Patentc 5,~'72,236 and 5,278,272. Substantially linear olef_n interpolymers are more preferred olefinic polymers.
The preferred ethylene/a-olefi~ polymers have a density (measured in accordance with ~,STM D-792) of not less than about 0.850, more preferably not less than about 0.855, and most preferably not less than about 0.860 g/cm3 and not more than about 0.900, more preferably not more than about 0.885, and most preferably not more than about o 0.880 g/cm3; a weight average molecular weight to number average molecular weight ratio (Mw/Mn~ from 1.5 to 3.0, a measured meit index (measured in accordance with ASTM D-1238 (190/2.16!) of not less than about 0.1, more preferably not less than about 0.5, and most preferably not less than about 1 g/10 min, to no- greater than about 1000, more preferably not greater tha~l about 500, and most preferably not greater than 100 g/10 .nin; and an I10/I2 of from 6 to 20, more preferably to abou_ 14 (measured in accordance with ASTM D-1238 (190/10)).
In order to produce an ink composition according to the present in~ention, a binder is f ~st prepared by direct emulsification of the polyolefin resin. The emulsification can be accomplished by methods well known for the emulsification of olefin polyners. Preferably, 2~ the binder emulsion is prepared accor~ling to the method of U.S. Patent 5,539,021 (Pate et al.) or the method of U.S.
Patent 5,574,091 (Walther et al.). The colorant typically is then dispersed in an alkali soluble styrenated acrylic solution resin or other dispersant; alternatively, a predispersed pigment base, such as FLEXIVERSE brand pigment dispersion (commercially available from Sun Chemical, Inc.) can be used. The binder and the colorant are then mixed This is typical;y followed by the addition of other materials common to ink formulations (hereinafter referred to as additives) including, for example, wax, anti-foaming agent, solvent (such as n-propanol or isopropanol), surfactant and further water asthe occasion demands to thereby adjust: such properties as viscosity, color, appearance, and the like. Each additive may be a blend of materials, such as a blend of surfactants. Examples of solution resins or dispersants include copolymers of aromatic monomers, such as styrene, with common comonomers such as acrylic acid and maleic anhydride. MOREZ 101 is an example o: such a resin and is commercially available from Morton International, Inc.
The solids content of the additives ~ypically comprises less than 10 weight percent of t:-e to~al solids of the ink or coating composition. It is also possible to add the additives to the binder.
The inks and coatings of ~he F,resent invention can be applied lo substrates by a variety of techniques including flexography, rotogravure, screen printing, ink jet printing, spray coating and other common printing and coating techniques. The composi-ions of the invention are especially useful as inks and coating, for plastic substrates. Surprisingly, the compositions of the invention do not require corona, flame, or chemical treatment to have good adhesion .o untreated plastic substrates, that is, they have good adhesion to untreated plastic substrates. When used as coatings, the compositions can be employed, for exa~~ple, as overprint varnishes and clearcoats.
The present invention is illustrated further by the following examples which are meant to be illustrative only and are not meant to limit in any manner the scope of the invention as set forth in the following clai~s. All parts and percentages are by weight unless c,therwise specified.
Example 1 A polyolefin dispersion was prepared from a base resin having the following characteristics: a polymer density of 0.855 gicm3 and a melt index of 0.5 g/10 min.
The resultant polyolefin emulsion is 50 percent solids, contains 2 percent sodium dodecyl ben.zene sulfonate 0 anionic surfactant, and had a particle size of 0.90 microns. Inks were made from 100g of this binder dispersion using the procedure listed below and the following materials:
5g of DC51 polydimethylsiloxane additive (commercially available from the Dow Corning Corporation) 10g of deionized water 100g Ot FLEXIVERSE RFD-9587 l-thol rubine red pigment dispersion (commercially available from Sun Chemical, Inc.) 0.2g o SURFYNOL 104H surfactant ~commercially available from Air Products, Inc ).
The DC51 was mixed into a paste with the deionized water. The FLEXIVERSE pigment dispersion was added and the mixture was stirred for 10 minutes using a Cowles high-speed disperser The SURFYNOL 104H surfactant was added with stirring. The polyolefin ~ispersion was added slowly with stirring. The mixture was stirred for an =, , ~
additional 10 minutes following the addition of the polyolefin dispersion.
The ink was stable and coagulum-free. The formulated ink was separated into two batches, each comprising 50 percent of the total ink. Then, 7.5g of n-propanol was added to one of batches. The ink remained stable on the addition of the n-propanol.
The adhesion to various subst:ates was tested using o the following procedure: The ink was applied to untreated LLDPE (linear low density polyethylene) using a #5 Meyer rod, which gave a dry film thickness of less than 3 microns. A hard rubber sheet was us~d to support the substrate while the drawdown was made. The wet ink film was dried in an oven at various temperatures for 30 seconds. Adhesion was tested by applying a 3" strip of #610 SCOTCH brand tape to the printecL film and removing it with a sharp pull. The adhesion was expressed in terms of the percentage of ink film which remained on the substrate.
Temperature (~C)% ~dhesion 4~ 1~
>~5 1~0 This example demonstrates that adhesion improves as the drying temperature is raised.
Example 2 Inks were prepared using the formulation from Example 1, except that the polyolefin dispersion was ,. ., ., , ., ~ . ,,.. . ",.. .. ~ , .
replaced with polyolefin binders with the following characteristics:
InkResin Resin Melt Dispersion Surfactant Density Index Particle Concentration (g/cm3) (g/lOmin) Diameter (% based on (~m) solids) A 0.856 60 1.0 2.0 B 0.870 70 0.7 2.0 s The ink films were applied to an LLDPE substrate in the same manner as Example 1. The adhesion was tested in the same manner as Example 1, giving the following results:
Temperature (~C) % Adhesion - Ink % Adhesion - Ink A B
This example shows that increc~sing ethylene interpolymer resin density requires higher temperature for good adhesion.
Example 3 Ink A from Example 2 was applied to several substrates and the adhesion was tested using the method described in Example 1. The drying temperature was 60~C
and the drying time is 30 seconds.
Substrate % Adhesion Aluminum foil 80 Corona Treated High Slip LDPE 95 Untreated High Slip LDPE 10 Untreated HDPE 90 Untreated LLDPE 100 Example 4 Inks were made using the basic formulation of Example 1 and -he following FLEXIVERSE pigment dispersions: ~ithol rubine red (RFD-9587); phthalo blue (BFD-1121); and diarylide yellow (YFD--1123). All of the inks were stable and coagulum-free.
Example 5 Additives were added to the ink formulation to modify the resolubility of the formu ated ink. The polyolefin dispersion had the following characteristics:
a resin density of 0.870 g/cm3, a mel~ index of 70g/10 min, an average particle diameter of ~.30 microns (measured using a Cou.ter Count.er), a surfactant concentration of 6 percent sodium dodecyl benzene sulfonate (based on polymer solids) and a solids content of ~4 percent. Inks are made with the following formulations:
Ink C Ink D Ink E Ink F
Ingredient pigment CA 02247003 l998-09-09 dispersion MOREZ 101 6.6 16.6 16.6 resin NH~OH (28%) ~.8 Ethanolamine 5.8 5.8 Deionized 10 42 42 42 water SURFYNOL 104H 0.2 ~.2 0.2 0.2 Diethylene 2.7 glycol Polyolefin 100 100 100 100 dispersion The nks were prepared using the following procedure: The neutralizing base (ammonia or ethanolamine~, and (optionally) -he diethylene glycol were added to the deionized water. The MOREZ 101 solution resin was added to this solution. The mixture was heated to 80~C and was stirred gently until the solid resin dissolved. The MOREZ 101 solution was allowed to cool to room temperature.
The FLEXIVERSE pigment d_spersion was added to a 240 ml (8 oz.) glass jar. The reutralized solution resin was added to the FLEXIVERSE with stirring, using a Cowles high-speed disperser. The mixtu-e was stirred for 10 minutes prior to addition of the polyolefin emulsion with stirring. Finally, the SURFYNOL 104H surfactant was added with stirring. The mixture was stirred for an additional 10 minutes following the addition of the polyolefin dispersion.
, Resolubility was determined according to the following procedure: Wet ink films less than 0.10 mm (4 mils) thick were applied to a stainless steel substrate and dried for 15 minutes. A drop of dilute weak base s solution was then placed on the dry film. The dissolution of the dried ink film was then observed. The resolubility was defined to be poor if the ink film did not begin to redisperse within 30 seconds, good if the ink film did not redisperse within 10 seconds, and excellent if the ink o film was redispersed within 3 seconds Ink Resolubility C poor D good E excellent F excellent Example 6 A polyolefin dispersion was prepared from a base resin having the following characteri,tics: a polymer density of 0.863 g/cm3 and a melt index of 0.5 g/10 min.
The resultant polyolefin dispersron was 50 percent solids, contains 2 percent sodium dodecyl benzene sulfonate anionic surfactant, and had an average particle diameter of 1.0 microns.
Formulated coatings are prepared using this polyolefin dispersion according to formulations A and B as shown in Table A below. Styrene/buta~liene and acrylic latexes, formulations C and D respectively, were used as controls.
Table A. Various coating formulations (% w/w dry) Formulation A B C D
Polyolefin Emulsion 100 50 Styrene/Butadiene Emulsion 100 Acrylic Emulsion 100 Calcium Carbonate 39.8 Titanium Dioxide 10 Polyacrylate Thickener 0.2 % Solids 50 58 50 50 Coatings A through D were coated on thermoplastic polyolefin with a 0.15 mm (6 mil) gap bird drawdown bar and were dried in a forced air oven at 100~C for 10 minutes. Adhesion was tested by applying a 7.6 cm strip of #610 SCOTCH brand tape to the coated film and removing it with a sharp pull. The adhesion was expressed in terms of the percentage of ink film remaining on the substrate.
Coating from % Adhesion Formulation C O
This example illustrates ~hat ~learcoats and pigmented coatings can be prepared with polyolefin s binders, and have superior adhes-on to a thermoplastic polyolefin substrate.
Example 7: Ink where colorant is a soluble dye.
0 To 200 gm of toluene was added: 4.9 gm Oil Red O
(CAS 1320-06-5; 50.1 gm of an et:~.ylene/octene copolymer (70 melt index, 0.870 density); ~.0 ~n sodium dodecybenzene sulfonate (Rhodacal~ DS--10, Rhone Poulenc);
and 116.5 gm water.
This was treated to high shear mixing using an IKA~
S25-25G disperser running at about 50l~0 rpm for 15 minutes. The emulsion was rinsed Wit'l water into a stripping flask. Toluene was removed from the emulsion by vacuum stripping at 50QC. The ink emulsion had a solids content of 13.95 percent. To about 5 cc of this ink, one drop of SURFYNOL~ 104 was added. A drop of this formulation was drawn up into a hollow glass fiber, which was used as a pen. Writing was perfonmed upon various plastic film surfaces, including low density polyethylene, polyester, and oriented polypropylene. The resulting indicia were dried in an oven at 65QC, and were found to be substantive to these surfaces, showing good abrasion and handling resistance. This example shows that an ink with excellent adhesion to plastic substrates can be produced with an oil soluble dye as the colorant.
43164 -~5-
WATER-BASED COATIN'-,S
This invention relates to water-borne coatings, s including inks, their composition and their use as surface and lamination coatings on paper and plastic substrates such as polyolefin, polyester, and poiyamide.
A growing area in the field of printing is known as flexography or flexographic ink printing. Flexographic o ink printing is a branch of rotary typographic printing in which the pr_nting is applied to a print-receiving substrate by use of a flexible relief plate with highly fluid, volat~le inks which dry rapidly by evaporation.
Flexography s widely utilized for printing on plastic films. Another process which is widely utilized for printing on plastic films is the gravure process. In this process the printing image is engraved into a cylinder in the form of cells which become filled with ink. Printing is achieved b~ passing the substrate between the gravure cylinder and an impression roller under pressure.
A flexographic or gravure printing ink generally contains three basic types of ingredients denominated as a solvent, a colorant, and a binder. Minor amounts of other additives also may be employed to provide the desired 2s characteristics (such as rheology, viscosity, printability) for the printing ink ccmposition.
Liquid printing inks dry by solvent evaporation, usually with heat or air blower assistance. Solvent systems may be either water systems which use water as a partial or total solvent, or systems using volatile organic solvents. Primary organic sclvents are usually ~, .
alcohols, thou3h some contain other o~genated solvents.
In recent years, increased emphasis has been placed on the use of water as the solvent, rather than an organic solvent. In keeping with this trend, a wide variety of colorants or pigments have been developed for use in water-based ink formulations.
The binder component of the printing ink composition generally comprises a resin which functions primarily to increase adhesion of the pigment to the o substrate, while also often acting as a dispersing medium and carrier. Specific acrylic polyme:r latexes are commonly employed as binders in -~ater-based printing ink compositions. For example, U.S. Patent 4,980,408 discloses water-based printing i~ks wherein the binder is based on an acrylated rosin modified polyamide resin and a latex resin. U.S. Patent 5,498,661 discloses aqueous inks wherein the binder is prepared by emulsion polymerizing a monomer mixture which contains variou, acrylates.
However, one of the major shortcomings of using water-based inks (relative to the traditional solvent-based alternatives) for printing on plastic film is a lack of adhesion of the ink film. That is, the acrylic binders used in water-based inks do not -eadily adhere to low surface energy plastic substrates. Therefore, the ink films tend to lose their adherence to plastic films, thereby making the ink smear or run. Thus, good adhesion to plastic substrates is a highly desired characteristic because of the handling that many printed packages receive.
Therefore, it would be desira~)le to have aqueous emulsion binders for use in preparing water-based printing inks which, when utilized for printing on plastic films, ~" . ,., ~ ,, , .. , .. ,, .. , " .. ,.,., .. ", .. . .
~ ' ~, .
exhibit increased adhesion. Heretofore/ emulsified polyolefin resins have not been employed in aqueous coatings, including inks, as the binder.
The present invention is directed to novel water-based coating compositions comprising an emulsifiedpolyolefin resin, preferably a substantially linear olefin interpolymer, as the binder. The invention also includes surface printing inks comprising such a binder. The inks and coatings of the present invention are superior in o printing aptitude and adhesion to plastic surfaces.
The aqueous ink of the invention comprises a solvent, a colorant, a binder, and other materials common to ink formulations.
In the aqueous compositions of the invention, the solvent is primarily water, that is, the solvent can be water alone or can be water with mincr amounts of solvent additives such as low molecular weight alcohols, as is well known in the art.
A colorant is any material which gives color to the ink, including, for example, pigmentC and dyes. Colorants are widely available commercially and are well known to those skilled in the art.
The binder resin is an essential ingredient in the ink formulation and promotes pigment binding, good adhesion, clean printing, and excellent film wetting. The binder is employed in an amount sufficient to bind the colorant and provide adhesion to the substrate.
Preferably, the a~ueous ink or coating of the invention comprises from 40 to 80 percent by weight binder based on 30 the solids content of the ink. More preferably, the aqueous ink or coating of the invention comprises from 50 to 70 percent by weight binder based on the solids content of the ink. The solids in the colorant and additives comprise the balance of the solids in the ink or coating composition. The binder may comprise mixtures or blends of polyolefin resins. Preferably, the average particle size of the particles in the binder is not more than 2 microns, more preferably is not more than 1.5 microns and most preferably is not more than 0.5 micron. Preferably, o the average particle size of the particles in the binder is at least 0.3 micron, more preferab]y is at least 0.1 micron and most preferably is at least: 0.05 micron.
The binders of invention comprise at least one homogeneous ethylene/a-olefin interpo:Lymer which is an interpolymer of ethylene and at ;east one C3-C20 a-olefin.
The term "interpolymer" is used herein to indicate a copolymer, or a terpolymer, or a higher order polymer.
That is, at least one other comonomer is polymerized with ethylene to make the interpolymer. The term "substantially linear olefin interpolymerU as used herein means the polymers disclosed in U.S. :?atent 5,665,800 (Lai et al.).
Preferred olefinic polymers include homogeneously branched, linear ethylene/a-olefin copolymers such as TAFMER~ (a trademark of Mitsui PetroChemicals Company Limited) and EXACT~M (a trademark of Exxon Chemical Company), which can be prepared as de,cribed in U.S.
Patent 3,645,992, homogeneously branched, substantially linear ethylene/a-olefin polymers suc:h as AFFINIT~M
polyolefin plastomers (trademark of The Dow Chemical Company) and ENGAGE~ polyolefin elastomers (trademark of DuPont Dow Elastomers) which can be prepared, for example, by a process disclosed in U.S. Patentc 5,~'72,236 and 5,278,272. Substantially linear olef_n interpolymers are more preferred olefinic polymers.
The preferred ethylene/a-olefi~ polymers have a density (measured in accordance with ~,STM D-792) of not less than about 0.850, more preferably not less than about 0.855, and most preferably not less than about 0.860 g/cm3 and not more than about 0.900, more preferably not more than about 0.885, and most preferably not more than about o 0.880 g/cm3; a weight average molecular weight to number average molecular weight ratio (Mw/Mn~ from 1.5 to 3.0, a measured meit index (measured in accordance with ASTM D-1238 (190/2.16!) of not less than about 0.1, more preferably not less than about 0.5, and most preferably not less than about 1 g/10 min, to no- greater than about 1000, more preferably not greater tha~l about 500, and most preferably not greater than 100 g/10 .nin; and an I10/I2 of from 6 to 20, more preferably to abou_ 14 (measured in accordance with ASTM D-1238 (190/10)).
In order to produce an ink composition according to the present in~ention, a binder is f ~st prepared by direct emulsification of the polyolefin resin. The emulsification can be accomplished by methods well known for the emulsification of olefin polyners. Preferably, 2~ the binder emulsion is prepared accor~ling to the method of U.S. Patent 5,539,021 (Pate et al.) or the method of U.S.
Patent 5,574,091 (Walther et al.). The colorant typically is then dispersed in an alkali soluble styrenated acrylic solution resin or other dispersant; alternatively, a predispersed pigment base, such as FLEXIVERSE brand pigment dispersion (commercially available from Sun Chemical, Inc.) can be used. The binder and the colorant are then mixed This is typical;y followed by the addition of other materials common to ink formulations (hereinafter referred to as additives) including, for example, wax, anti-foaming agent, solvent (such as n-propanol or isopropanol), surfactant and further water asthe occasion demands to thereby adjust: such properties as viscosity, color, appearance, and the like. Each additive may be a blend of materials, such as a blend of surfactants. Examples of solution resins or dispersants include copolymers of aromatic monomers, such as styrene, with common comonomers such as acrylic acid and maleic anhydride. MOREZ 101 is an example o: such a resin and is commercially available from Morton International, Inc.
The solids content of the additives ~ypically comprises less than 10 weight percent of t:-e to~al solids of the ink or coating composition. It is also possible to add the additives to the binder.
The inks and coatings of ~he F,resent invention can be applied lo substrates by a variety of techniques including flexography, rotogravure, screen printing, ink jet printing, spray coating and other common printing and coating techniques. The composi-ions of the invention are especially useful as inks and coating, for plastic substrates. Surprisingly, the compositions of the invention do not require corona, flame, or chemical treatment to have good adhesion .o untreated plastic substrates, that is, they have good adhesion to untreated plastic substrates. When used as coatings, the compositions can be employed, for exa~~ple, as overprint varnishes and clearcoats.
The present invention is illustrated further by the following examples which are meant to be illustrative only and are not meant to limit in any manner the scope of the invention as set forth in the following clai~s. All parts and percentages are by weight unless c,therwise specified.
Example 1 A polyolefin dispersion was prepared from a base resin having the following characteristics: a polymer density of 0.855 gicm3 and a melt index of 0.5 g/10 min.
The resultant polyolefin emulsion is 50 percent solids, contains 2 percent sodium dodecyl ben.zene sulfonate 0 anionic surfactant, and had a particle size of 0.90 microns. Inks were made from 100g of this binder dispersion using the procedure listed below and the following materials:
5g of DC51 polydimethylsiloxane additive (commercially available from the Dow Corning Corporation) 10g of deionized water 100g Ot FLEXIVERSE RFD-9587 l-thol rubine red pigment dispersion (commercially available from Sun Chemical, Inc.) 0.2g o SURFYNOL 104H surfactant ~commercially available from Air Products, Inc ).
The DC51 was mixed into a paste with the deionized water. The FLEXIVERSE pigment dispersion was added and the mixture was stirred for 10 minutes using a Cowles high-speed disperser The SURFYNOL 104H surfactant was added with stirring. The polyolefin ~ispersion was added slowly with stirring. The mixture was stirred for an =, , ~
additional 10 minutes following the addition of the polyolefin dispersion.
The ink was stable and coagulum-free. The formulated ink was separated into two batches, each comprising 50 percent of the total ink. Then, 7.5g of n-propanol was added to one of batches. The ink remained stable on the addition of the n-propanol.
The adhesion to various subst:ates was tested using o the following procedure: The ink was applied to untreated LLDPE (linear low density polyethylene) using a #5 Meyer rod, which gave a dry film thickness of less than 3 microns. A hard rubber sheet was us~d to support the substrate while the drawdown was made. The wet ink film was dried in an oven at various temperatures for 30 seconds. Adhesion was tested by applying a 3" strip of #610 SCOTCH brand tape to the printecL film and removing it with a sharp pull. The adhesion was expressed in terms of the percentage of ink film which remained on the substrate.
Temperature (~C)% ~dhesion 4~ 1~
>~5 1~0 This example demonstrates that adhesion improves as the drying temperature is raised.
Example 2 Inks were prepared using the formulation from Example 1, except that the polyolefin dispersion was ,. ., ., , ., ~ . ,,.. . ",.. .. ~ , .
replaced with polyolefin binders with the following characteristics:
InkResin Resin Melt Dispersion Surfactant Density Index Particle Concentration (g/cm3) (g/lOmin) Diameter (% based on (~m) solids) A 0.856 60 1.0 2.0 B 0.870 70 0.7 2.0 s The ink films were applied to an LLDPE substrate in the same manner as Example 1. The adhesion was tested in the same manner as Example 1, giving the following results:
Temperature (~C) % Adhesion - Ink % Adhesion - Ink A B
This example shows that increc~sing ethylene interpolymer resin density requires higher temperature for good adhesion.
Example 3 Ink A from Example 2 was applied to several substrates and the adhesion was tested using the method described in Example 1. The drying temperature was 60~C
and the drying time is 30 seconds.
Substrate % Adhesion Aluminum foil 80 Corona Treated High Slip LDPE 95 Untreated High Slip LDPE 10 Untreated HDPE 90 Untreated LLDPE 100 Example 4 Inks were made using the basic formulation of Example 1 and -he following FLEXIVERSE pigment dispersions: ~ithol rubine red (RFD-9587); phthalo blue (BFD-1121); and diarylide yellow (YFD--1123). All of the inks were stable and coagulum-free.
Example 5 Additives were added to the ink formulation to modify the resolubility of the formu ated ink. The polyolefin dispersion had the following characteristics:
a resin density of 0.870 g/cm3, a mel~ index of 70g/10 min, an average particle diameter of ~.30 microns (measured using a Cou.ter Count.er), a surfactant concentration of 6 percent sodium dodecyl benzene sulfonate (based on polymer solids) and a solids content of ~4 percent. Inks are made with the following formulations:
Ink C Ink D Ink E Ink F
Ingredient pigment CA 02247003 l998-09-09 dispersion MOREZ 101 6.6 16.6 16.6 resin NH~OH (28%) ~.8 Ethanolamine 5.8 5.8 Deionized 10 42 42 42 water SURFYNOL 104H 0.2 ~.2 0.2 0.2 Diethylene 2.7 glycol Polyolefin 100 100 100 100 dispersion The nks were prepared using the following procedure: The neutralizing base (ammonia or ethanolamine~, and (optionally) -he diethylene glycol were added to the deionized water. The MOREZ 101 solution resin was added to this solution. The mixture was heated to 80~C and was stirred gently until the solid resin dissolved. The MOREZ 101 solution was allowed to cool to room temperature.
The FLEXIVERSE pigment d_spersion was added to a 240 ml (8 oz.) glass jar. The reutralized solution resin was added to the FLEXIVERSE with stirring, using a Cowles high-speed disperser. The mixtu-e was stirred for 10 minutes prior to addition of the polyolefin emulsion with stirring. Finally, the SURFYNOL 104H surfactant was added with stirring. The mixture was stirred for an additional 10 minutes following the addition of the polyolefin dispersion.
, Resolubility was determined according to the following procedure: Wet ink films less than 0.10 mm (4 mils) thick were applied to a stainless steel substrate and dried for 15 minutes. A drop of dilute weak base s solution was then placed on the dry film. The dissolution of the dried ink film was then observed. The resolubility was defined to be poor if the ink film did not begin to redisperse within 30 seconds, good if the ink film did not redisperse within 10 seconds, and excellent if the ink o film was redispersed within 3 seconds Ink Resolubility C poor D good E excellent F excellent Example 6 A polyolefin dispersion was prepared from a base resin having the following characteri,tics: a polymer density of 0.863 g/cm3 and a melt index of 0.5 g/10 min.
The resultant polyolefin dispersron was 50 percent solids, contains 2 percent sodium dodecyl benzene sulfonate anionic surfactant, and had an average particle diameter of 1.0 microns.
Formulated coatings are prepared using this polyolefin dispersion according to formulations A and B as shown in Table A below. Styrene/buta~liene and acrylic latexes, formulations C and D respectively, were used as controls.
Table A. Various coating formulations (% w/w dry) Formulation A B C D
Polyolefin Emulsion 100 50 Styrene/Butadiene Emulsion 100 Acrylic Emulsion 100 Calcium Carbonate 39.8 Titanium Dioxide 10 Polyacrylate Thickener 0.2 % Solids 50 58 50 50 Coatings A through D were coated on thermoplastic polyolefin with a 0.15 mm (6 mil) gap bird drawdown bar and were dried in a forced air oven at 100~C for 10 minutes. Adhesion was tested by applying a 7.6 cm strip of #610 SCOTCH brand tape to the coated film and removing it with a sharp pull. The adhesion was expressed in terms of the percentage of ink film remaining on the substrate.
Coating from % Adhesion Formulation C O
This example illustrates ~hat ~learcoats and pigmented coatings can be prepared with polyolefin s binders, and have superior adhes-on to a thermoplastic polyolefin substrate.
Example 7: Ink where colorant is a soluble dye.
0 To 200 gm of toluene was added: 4.9 gm Oil Red O
(CAS 1320-06-5; 50.1 gm of an et:~.ylene/octene copolymer (70 melt index, 0.870 density); ~.0 ~n sodium dodecybenzene sulfonate (Rhodacal~ DS--10, Rhone Poulenc);
and 116.5 gm water.
This was treated to high shear mixing using an IKA~
S25-25G disperser running at about 50l~0 rpm for 15 minutes. The emulsion was rinsed Wit'l water into a stripping flask. Toluene was removed from the emulsion by vacuum stripping at 50QC. The ink emulsion had a solids content of 13.95 percent. To about 5 cc of this ink, one drop of SURFYNOL~ 104 was added. A drop of this formulation was drawn up into a hollow glass fiber, which was used as a pen. Writing was perfonmed upon various plastic film surfaces, including low density polyethylene, polyester, and oriented polypropylene. The resulting indicia were dried in an oven at 65QC, and were found to be substantive to these surfaces, showing good abrasion and handling resistance. This example shows that an ink with excellent adhesion to plastic substrates can be produced with an oil soluble dye as the colorant.
43164 -~5-
Claims (10)
1. A water-borne ink composition comprising a binder which comprises of an emulsified polyolefin resin.
2. The composition of Claim 1 wherein the polyolefin resin comprises from 40 to 80 weight percent, based on solids, of the composition.
3. An aqueous printing ink composition comprising a colorant and an aqueous polymer emulsion binder wherein the binder comprises a substantially linear olefin interpolymer.
4. The composition of Claim 1 wherein the polyolefin comprises a substantially linear ethylene/.alpha.-olefin copolymer having a density from 0.850 to 0.890 g/cm3, an Mw/Mn from 1.5 to 3.0, a melt index of 0.1 to 1000 g/10 min, and an I10/I2 of at least about 5.63.
5. The composition of Claim 1 wherein the polyolefin comprises a substantially linear ethylene/.alpha.-olefin copolymer having: (a) a melt index, between 0.1 and 1000 g/10min; (b) a polymer density between 0.850 and 0.890 g/cm3; and (c) a particle diameter of from 0.05 micron to 2 microns.
6. The composition of Claim 1 wherein the polyolefin is an ethylene/1-octene copolymer having a density from 0.850 to 0.880 g/cm3, and a melt index from 0.5 to 100 g/10 min.
7. A water-borne coating composition comprising a binder comprising an emulsified polyolefin resin.
8. The composition of Claim 7 wherein the polyolefin resin comprises from 40 to 100 weight percent, based on solids, of the binder.
9. The composition of Claim 8 wherein the composition comprises up to 60 weight percent, based on solids in the composition, of colorant.
10. The composition of Claim 7 wherein the weight percent solids of the composition is from 50 to about 65.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US5835497P | 1997-09-10 | 1997-09-10 | |
| US60/058,354 | 1997-09-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2247003A1 true CA2247003A1 (en) | 1999-03-10 |
Family
ID=22016314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2247003 Abandoned CA2247003A1 (en) | 1997-09-10 | 1998-09-09 | Water-based coatings |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2247003A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103541235A (en) * | 2013-10-23 | 2014-01-29 | 合肥聚合辐化技术有限公司 | Water emulsion type polyester acrylate printing adhesive and preparation method thereof |
| CN103541233A (en) * | 2013-10-23 | 2014-01-29 | 合肥聚合辐化技术有限公司 | Waterproof flexible printing adhesive and preparation method thereof |
-
1998
- 1998-09-09 CA CA 2247003 patent/CA2247003A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103541235A (en) * | 2013-10-23 | 2014-01-29 | 合肥聚合辐化技术有限公司 | Water emulsion type polyester acrylate printing adhesive and preparation method thereof |
| CN103541233A (en) * | 2013-10-23 | 2014-01-29 | 合肥聚合辐化技术有限公司 | Waterproof flexible printing adhesive and preparation method thereof |
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