WO2005044934A1

WO2005044934A1 - Vegetable oil ester imide as a dispersant of carbon black in oil-based inks

Info

Publication number: WO2005044934A1
Application number: PCT/US2004/035105
Authority: WO
Inventors: Olgierd Wasilewski; Neil Young; Albert A. Kveglis
Original assignee: Sun Chemical Corp
Current assignee: Sun Chemical Corp
Priority date: 2003-10-29
Filing date: 2004-10-25
Publication date: 2005-05-19
Anticipated expiration: 2006-04-29

Abstract

The present invention relates an ink composition containing the reaction product of a maleated vegetable oils with various mono or polyamines. This invention relates to novel carbon black news ink compositions and methods of preparing the same. The better rheological properties of the inks makes them better suited for printing needs. The inks produced exhibit improved pigment wetting and flow as well as reduced viscosity when incorporated into black no-heat news inks. Due to better flow, improved rub-off is achieved.

Description

VEGETABLE OIL ESTER IMIDE AS A DISPERSANT OF CARBON BLACK IN OIL- BASED INKS

BACKGROUND OF THE INVENTION Field of the Invention [0001] This invention relates to oil based inks containing dispersed carbon black. Description of the Related Art [0002]News inks are prepared by mechanically dispersing carbon black in mineral oil. The oil serves as a vehicle for the carbon particles. The properties of the dispersion are very important in the ultimate use of the ink. [0003]Black no-heat news inks are formed from conventional furnace carbon blacks by dispersing the black in ordinary mineral oils to a concentration required for good printing, which usually is in the range of 10 to 20% by weight of the carbon black particles. Carbon blacks tend to chain together to form a dispersion having undesirable properties when conventional furnace carbon blacks are dispersed in ordinary mineral oils to a concentration required for good printing. This can be overcome by adding more oil to the dispersion, but it would ordinarily make the pigmentation too weak. It is customary, instead, to give the ink the required "length" by making use of mineral oil containing resinous compounds or substances, or asphaltic still bottoms rich in polar compounds, which will coat the carbon particles and reduce their tendency to chain together. [0004] One of the problems present in the existing art is that no heat litho inks based on mineral oils exhibit a marked tendency, especially in blacks to rub off on handling newsprint. To produce inks having low rub-off properties it is known in the prior art to add waxes of various types to the inks and the resultant inks will exhibit improved mar-resistance and better slip and water repellency properties. Wax can be mixed or ground into the batch along with pigments or may be introduced during the final blending operations. Alternatively, the wax may be compounded into a "wax media" by dispersing or melting the wax into varnishes and/or solvents and adding these to the ink. [0005]However, the addition of wax to solve the rub-off problem introduces other problems. First, an added wax only provides minimal rub-off reduction in news ink formulations. Second, with the heat and movement imparted by the friction of constant rubbing under pressure, particles of the ink film can ball up and mark unprinted areas. Introducing more wax to improve rub resistance properties only introduces more problems with respect to gloss and hardness characteristics. The addition of wax to ink almost invariably decreases the ink's level of gloss. Accordingly, a compromise must be achieved between the desired level of non-rub properties and gloss. [0006]Another solution is to incorporate hydrocarbon resins. This, however, raises the ink cost to an unacceptable level for this very price-sensitive printing area. [0007]An alternative solution is to disperse the carbon black particles to such a degree that the surface is completely wetted out. The results of optimized dispersion include, at a fixed pigment loading, the following: better color strength, lowered viscosity and increased flow. This increased flow is believed to contribute to reduced rub-off due to increased penetration of the ink into the porous newsprint paper. [0008]U.S. Pat. No. 4,747,964, describes the use of alkenyl succinirnides as components of dispersing additive compositions for lubricating oils. E. S. Forbes and E. L. Newstadter's publication in Tribology, (April 1972, pp. 72-77) elucidates the mechanics of the action of polyisobutylene succinimide in stabilizing the suspension of carbonaceous matter and to prevent the formation of sludge in motor lubricating oils. Polyisobutylene succinimide was therefore described as exhibiting good adsorption affinity towards particulates of carbon black. The rational is that long chains of surfactant extended from the surface of particles sterically hinder flocculation and the formation of agglomerates. [0009] A poly-isobutylene succinimide, such as Lubrizol 2155 available from Lubrizol Corp., has heretofore been employed as a dispersant (i.e., surfactant) for the carbon black particles of an oil-based news ink with good results. Even so, the rub off problem continues to exist in news prints to a undesirable degree.

BRIEF SUMMARY OF THE INVENTION [0010]The present invention addresses the rub-off problems that exist in prior oil- based printing inks by combining the oil with an additive comprising the reaction product of a maleated vegetable oil with various mono or polyamines. The resulting oil based printing ink exhibits improved pigment wetting and flow as well as reduced viscosity when incorporated into black no-heat news inks. Thus, a significant benefit of the current invention is the ability to form a oil-based printing ink that has improved rub-off characteristics. One aspect of the invention relates to an oil based printing ink that exhibits improved pigment wetting and flow as well as reduced viscosity when incorporated into black no-heat news inks. Due to better flow, improved rub-off resistance is achieved. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0011]Figure 1 is a viscosity versus sheer rate profile for oil based ink without any additive and for the ink with each of four different additives. Curve A is that of the ink with wood rosin ester dispersant prepared according to U.S. Patent RE 32,411 as the additive, curve B is that of the ink with polymerized linseed oil ester imide of Example 2 as the additive, curve C is that of the ink with coffee bean oil ester imide of Example 1 as the additive, and c rve D is that of the ink with poly-isobutylene succinimide, commercially available as Lubrizol 2155, as the additive.

DETAILED DESCRIPTION OF THE INVENTION [0012]Ink formulations for news ink generally comprise news ink grade carbon ^"black of from about 12 to about 20 wt.%, an ink base of refined mineral oil or vegetable oil of from about 70 to about 80 wt.%, surfactants, flow aids and/or anti-spray compounds of from about 3 to about 5 wt.% and distillate of from about 3 to about 5 wt.%. The mineral oil may be hydro- refined, solvent treated, naphthenic or a high viscosity specialist mineral oil. The mineral oil can be made up of a combination of viscosity grades ranging from 0.5 to over 100 poise. If as an ink base a vegetable oil is used it may, for example, be refined soya oil used in combination with a phenolic resin cooked in gelled Alkyd resin and soya oil The carbon black is usually rubber grade, intermediate particle-size furnace blacks. The grades of carbon black and of the oils that are suitable for production of no-heat news inks are well known to those of ordinary skill in the art and need no further description. [0013]In news ink formulas as above, a poly-isobutylene succinimide, such as Lubrizol 2155, has heretofore been employed as a dispersant (i.e., surfactant) for the carbon black particles with good results. Although such news inlcs have many desirable properties they still present various flow and rub-off problems. [0014]This invention comprises the discovery of a dispersing agent for the carbon black that may replace the poly-isobutylene succinimide dispersing agent, or may be used in conjunction therewith, to reduce the flow and rub-off problems heretofore experienced. The dispersant so discovered comprises the reaction product of a maleated vegetable oil with various mono or polyamines. This reaction product is believed to be an ester imide derivative of the maleated vegetable oil. [0015]Any vegetable oil that is capable of undergoing a reaction with maleic anhydride may be used in this invention. The vegetable oil is reacted with 3-10 parts maleic anhydride or a derivative thereof per 100 parts vegetable oil, usually at an elevated temperature of about 200° C, for a time sufficient to allow for complete reaction of the maleic anhydride. The maleated vegetable oil is thereafter reacted with a dialkylene amine or a trialkylene tetraamine, in an amount stoichiometric to the formation of the desired vegetable oil-based polymaleimide. This reaction may be carried out at elevated temperatures in the range of 140° to about 200° C for a time sufficient to allow for complete reaction of the amine reagent. [0016] Illustrative of the vegetables oils that may be used are coffee bean oil and the natural drying oils such as linseed oil, soybean oil, safflower oil, rung oil, dehydrated castor oils, polymerized linseed oil, polymerized soyabean oil, polymerized safflower oil an the like. Of these, polymerized linseed oil and coffee bean oil are preferred. Polymerized linseed oil is itself well known and is made by heating pure linseed oil in an airtight oxygen-free environment at about 288° C for about half a day. It is very viscous and is a very bright and clear honey-like substance that has a relatively slow drying time and a low acid content. The preparation of coffee bean oil from coffee grounds is well known. Coffee bean oil comprises about 75% of triglycerides and about 20% of fatty acid monoesters of two diterpene alcohols, namely caffestol and kahweol. [0017]The mono and polyamines that may be used in a practice of this invention may of the following formula:

R- -N- -R or

H₂

wherein each R may be the same or different alkyl group of from one to six carbon atoms, R' and R" are the same or different alkylene group of from one to six carbon atoms and x is a value of 1 to 6. Preferably each R is an ethyl group and each R' and R" is an ethylene group and x is 2. Hence the preferred monoamine is diethylamine and the preferred polyamine is triethylenetetramine. [0018]This additive is added with mixing to the ink composition to the extent of about

0.5 to about 4.0 wt.%, preferably about 1.5 to about 2.5 wt.%, more preferably to the extent of about one part of additive to about each nine parts of carbon black. Example 1 [0019]88.5 parts of refined coffee bean oil was charged into a four-neck round bottom flask and heated to 205° C under a nitrogen blanket. To this, 7.0 parts of maleic anhydride was added. This mixture was then held for 3 hours at 205° C for reaction. Thereafter the mixture was cooled to 145° C. Then 4.5 parts of triethylenetetramine was added and this mixture was held for 1 hour at 145° C. After 1 hour the material was heated to 205° C and held at this temperature for an amine number below 3.0 and an acid number below 7.0. The product of this reaction was then cooled to 100° C and discharged. Example 2 [0020J87.5 parts of a polymerized linseed oil was charged into a four-neck round bottom flask and heated to 200° C under a nitrogen blanket. To this, 4.0 parts of maleic anhydride was added. This mixture was then held for 1 1/2 hours at 200° C for reaction. Thereafter the mixture was cooled to 145° C. Then 8.5 parts of diethylamine was added over 45 minutes and this mixture was held for 1 1/2 hour at 145° C. After this time the material was heated to 200° C and held at this temperature for an amine number of 0. The product of this reaction was then cooled to 100° C and discharged. Example 3 [0021] A cold set news ink based on a high structure carbon black, Elftex 115 from Cabot, asphaltic still bottoms from Ziegler, and 2400 SUS mineral oil from San Joaquin, wasprepared in a conventional manner according to the following formula:

WT.% Mineral Oil 79.5 Asphaltic Still Bottoms 2.5 Carbon Black 18.0 100.0

[0022]With this ink composition a series of materials were tested for their effects on wetting and deflocculation of the carbon black dispersion. 2 wt.% of each of the following materials were mixed in the ink: A. A wood rosin ester dispersant prepared according to U.S. Patent RE 32,411; B. The polymerized linseed oil ester imide of Example 2; C. The coffee bean oil ester imide of Example 1; and D. A poly-isobutylene succinimide, commercially available as Lubrizol 2155 from Lubrizol Corp. [0023]Each test ink was aged for 24 hours after its respective additive was mixed into it. The affect of the additive was then evaluated with a viscosity versus sheer rate profile. The viscosity versus sheer rate profile for the ink without any additive and for the ink with each of the additives identified above is give in Figure 1. In Figure 1 curve 1 is that of the ink without any additive, curve A is that of the ink with wood rosin ester dispersant prepared according to U.S. Patent RE 32,411 as the additive, curve B is that of the ink with polymerized linseed oil ester imide of Example 2 as the additive, curve C is that of the ink with coffee bean oil ester imide of Example 1 as the additive, and curve D is that of the ink with poly-isobutylene succinimide, commercially available as Lubrizol 2155, as the additive. [0024] As can be seen from Figure 1, the polymerized linseed oil ester imide of Example 2 and the coffee bean oil ester imide of Example 1 are powerful wetting compounds for carbon black in a mineral oil system. These materials have a strong affinity for carbon black and produce a strong deflocculating effect which manifest itself in a depressed low shear viscosity. Their use allows the desired dispersion quality to be attained in a shorter period of time and/or a higher pigment concentration to be carried during the dispersion process. [0025] The present invention has been described in detail, including the preferred embodiments thereof. However, it will be appreciated that those skilled in the art, upon consideration of the present disclosure, may make modifications and/or improvements on the invention that fall within the scope and spirit of this invention as set forth in the following claims.

Claims

CLAIMS We claim: 1. An ink composition, comprising: a) an ink base; b) carbon black; and c) an additive which is a product of reaction between a maleated vegetable oil and an amine 2. The ink composition according to claim 1, wherein the ink base comprises mineral oil. 3. The ink composition according to claim 2, wherein the carbon black comprises from about 12 to about 20 wt. % of the ink composition and the additive comprises from about

0.5 to about 4.0 wt. % of the ink composition. 4. The ink composition according to claim 3, wherein the additive is the product of reaction between a maleated polymerized linseed oil and an organic amine. 5. The ink composition according to claim 3, wherein tie additive is the product of reaction between a maleated coffee bean oil and an organic amine 6. The ink composition according to claims 4 and 5, wherein the amine is of the formula:

R- -N- -R or

H₂ N R¹— — N R^1L- T^{N H}2 wherein each R may be the same or different alkyl group of from one to six carbon atoms, R' and R' ' are the same or different allcylene group of from one to six carbon atoms and x is a value of l to β. 7. The ink composition according to claim 4 wherein the amine is diethylamine. 8. The ink composition according to claim 5 wherein the amine is triethylenetetramine . 9. A method for forming carbon black dispersant, comprising: a) combining and reacting an oil and a maleic anhydride or a derivative thereof to form a reaction product; and b) adding an organic amine to the reaction product such that the organic amine and the reaction product form an oil based polymaleimide. 10. The method according to claim 9, further comprising reacting the oil and maleic anhydride while heating under nitrogen. 11. The method according to claim 9, wherein the temperature of the reaction is about 150 °C to about 250 °C. 12. A dispersant for carbon black comprising an oil based polymaleimide. 13. The dispersant for carbon black according to claim 11, wherein the oil is selected from the group consisting of linseed oil and coffee bean oil. 14. The dispersant for carbon black according to claim 12, wherein the polymaleimide is formed from an organic amine is selected from the group consisting of triethylenetetramine and diethylamine.