DE2215267A1 - Printing ink binders - contg salts of carboxylated resins - Google Patents

Abstract

Water-free printing inks, esp. toluene-based inks, contg. salts of COOH-contg. polymeric resins as binder with an av.mol.wt. of 500-5000 and a degree of saponification of 10-370, such that 2-60% of the COOH units are converted into the corresp. salts with cations of gp. (I) metals and/or opt. substd. or quat.- NH4 + ions.

Description

Printing Inks The invention relates to printing inks, in particular Gravure inks.

Printing inks consist essentially of pigment, binder and Solvent. The printing properties of such systems result from the interaction of these components. Basically, the binder fulfills the Task to fix the pigment on the printed surface. In addition, should It makes it easier to disperse the pigment particles during the manufacture of the paint and favor. It is also supposed to keep the pigment particles in suspension and that Adjust the fluidity of the inks to the correct level for the respective printing process permit. Furthermore, the pigment should also be used during the printing process and in printing films wrap well. Dispersion and pigment wetting are enhanced by the chemical Structure of the resins significantly influenced, with a certain affinity between Resin and pigment proves beneficial.

This also includes important properties of the printed color films, such as depth of color, gloss and glaze in connection. These properties will however largely influenced by whether and to what extent the binder enters the pores and capillaries of the absorbent substrate, e.g. paper, migrates and then the Pigment parts can no longer adequately enclose. The following is this behavior of the binder-pigment system marked with the term "Status on the paper", which means that pressure applied to uncoated paper does not bleed through, so that the paper on the back is not visually altered.

After all, the drying process must take place as quickly as possible, i.e. the solvents used must be used as quickly as possible during the printing process and be completely removed. In the intaglio process, in which as a binding agent Solutions of resins in suitable solvents, preferably in toluene, are used this is done in a purely physical way by evaporation of volatile solvents, especially toluene.

Resins for gravure inks have hitherto been predominantly made from rosin through reaction with other components, e.g. phenol-formaldehyde resins, esterification agents et al., manufactured. They meet the requirements mentioned to a large extent, but it becomes more and more difficult to find them because of the increasing shortage of rosin to be provided in sufficient quantities. On the other hand, colors have to be purely synthetic Base on the basis of synthetic resins is generally not yet the most rounded Characteristics of colors based on high quality rosin resins. In particular They do not show a good stand of on non-machine-painted and therefore strong absorbent papers of the type preferred for wide use in gravure printing. Also the dispersibility and thus the gloss and the glaze of the gravure inks are mostly not yet satisfactory with the synthetic gravure printing resins used up to now.

The production of low-grade resins for gravure printing can e.g.

take place by radical polymerization. So is polystyrene in toluene readily soluble, but has the disadvantage that it dries too slowly and only one has low affinity for the pigments.

In contrast, copolymers made from styrene and / or styrene derivatives dry as well as from maleic anhydride and / or acrylic acid or

whose derivatives are built up faster. They also have a bigger one Affinity to the pigments, but show a poor one in oil inks Stand on the paper.

It is known that acidic groups with polyvalent resins are formed by salt formation Metals, especially those of the second group of the periodic table, especially Zinc and / or calcium, especially through resinate formation in products containing colophony, possibly with simultaneous esterification with polyhydric alcohols, for To improve printing inks. In order to achieve particularly good effects, the metals often used in relatively high amounts, which correspond to the acidic groups are equivalent. In this way, the molecular weight and melting point of the resins become increased.

This high proportion of salt groups can have a detrimental effect on the Viscosity and thus affect the further processing of the products. This way of working is also used with those modified petroleum resins that still contain carboxyl or anhydride groups included, carried out, however, according to the examples of a known method in addition, relatively high temperatures of 260 ° C can be used. at . decompose the resins become darker in color, the viscosity being reduced to that of the starting resin or drops even further.

There are also printing inks based on inorganic salts carboxyl group-containing aliphatic α-olefin polymer with monovalent Cations, water and pigments known. The polymers have to go through the Salt formation can be made water-soluble. According to the examples, this is 80 to 90% of the carboxyl groups, which make up 18 to 22 mol% of the Misehpolymerisats, under Salt formation neutralized in order to achieve sufficient solubility.

It was found; that non-aqueous inks, in particular are also suitable for toluene gravure printing, and salts of carboxyl group units as binders polymerisation resins having an average molecular weight of 500 to 5,000 and a saponification number of 10 to 370, included in the Salts 2 to 60 ç of the carboxyl group units with Cations of 1st group of the periodic system and / or with optionally substituted ammonium or quaternary ammonium ions have been reacted with the formation of corresponding salts are, do not have the disadvantages mentioned and have optimal properties.

"Carboxyl group units" here are those containing carboxyl groups or derivatives which form carboxyl groups, such as anhydride, ester, half-ester or amide groups to understand containing compounds. Vicinal carboxyl groups are preferred here, The term "non-aqueous" means that it does not contain water or is not miscible with water Medium to understand.

The polymerization resins are known in a manner known per se, e.g.

a) by polymerization of mono- and optionally diolefins and by subsequent reaction with unsaturated components containing carboxyl groups, e.g. by thermal, high-energy radiation such as electron beams or ultraviolet rays, or radical, see B. brought about by peroxides Addition of unsaturated acids, their anhydrides or esters, and / or b) through copolymerization of mono- and optionally diolefins with unsaturated carboxyl groups Components are manufactured. The preparation a) and b) can, for example, by radical Polymerization take place. Your salts used according to the invention are in non-aqueous organic solvents such as those used for printing inks, such as aromatics, e.g. toluene, but also in aliphatics, such as gasoline, or in mineral oils, sometimes even Soluble in every ratio.

The solution viscosity of those present in the printing inks of the invention Salts should be within certain limits. So you can use for toluene intaglio printing in generally a viscosity of 10 to 2000 cP, preferably 15 to 1000 cP (50 % in toluene / 20 ° C).

This viscosity can be controlled by the degree of salt formation. The softening point of the suitable salts is between 50 ° C and 150 ° C (capillary method).

Printing inks produced with such binders show an improvement the printing properties, in particular with regard to of Stand on absorbent papers as well as an increase in pigment absorption, des Whole and the glaze. This was surprising.

In the known processes involving salt formation with divalent ions and the products thus formed did not stick to the stand on paper at all thought, nor could such a property of these products be derived from it will. Even less was to be expected that an improvement in the printing technology Properties due to salt formation with monovalent ions, which - in contrast to the Salt formation with divalent cations - do not bring about an enlargement of the molecule, is possible, this applies in particular to the monovalent cations according to the invention Far from being in equivalents, but sometimes only in subordinate ones Amounts have been converted to the acid groups. The one made according to the invention Selection of a specific proportion of carboxyl group units that has been saponified is based on the discovery made here that usually by salt formation in high percentages the viscosity is increased too much and the printing technology Properties cannot be improved.

In addition, the carboxyl group units settle more easily Does not deal with group I cations.

The ratio of the converted to the total carboxyl groups present (each including the carboxyl group-containing derivatives) is hereinafter auoh with. 11 Degree of neutralization α ". It is thus defined as Moles of carboxylate groups α =, n (moles of carboxyl group units) where the Represents functionality of the carboxyl group units; at an anhydride group is she 2.

The salts used according to the invention or the underlying poly merisate can still be modified by further operations. As monomers of this Resins are preferably vinyl aromatics, such as styrene and / or its Derivatives such as methyl styrene, vinyl toluene, and aliphatic or cyclic ones Olefins / or diolefins called, such as monoolefins with 2 to q carbon atoms, e.g. propylene, Butylene, isobutylene, octene, butadiene, isoprene, cyclo- or dicyclopentadiene, cyclohexadiene, -heptadiene, vinyl pyridine, vinyl pyrrolidine.

Copolymers of such monomers with unsaturated monomers are preferred Connections that contain one or more of the carboxyl group units or Carboxyl groups, in particular anhydrides with vicinal carboxyl groups, contain. Suitable monomers with carboxyl group units are e.g. acrylic or methacrylic acid, Maleic acid, maleic anhydride or maleic acid half-esters with monohydric alcohols, also fumaric acid, citraoic acid, crotonic acid, tetrahydrophthalic acid or their corresponding saponifiable compound, each individually or as a mixture.

At least 50% of the copolymers used in accordance with the invention present monomers should be aromatic or cycloaliphatic in nature.

The polymers can also be in the form of telomerizates.

Preferably such olefinic, especially styrene-maleic acid anhydride telomers are used, the ratio of which is maleic anhydride: styrene 1: 2 to 1:20, preferably 1: 2 to 1: 8.

The following telomers are examples of suitable starting materials called t 1) those made from maleic anhydride and styrene (molar ratio 1: 2, 1: 3, 1: 5, 1: 8, those made of acrylic acid and styrene (molar ratio 1: 3) and 3) those from Maleic anhydride, styrene and α-methylstyrene (molar ratio lsl: l), the mentioned under 1) are preferably used.

Resins are also suitable which have been prepared by free-radical polymerization of artificial mixtures of the monomers mentioned or petroleum fractions arising from orackung, the component containing carboxyl groups, preferably an unsaturated mono- and / or dicarboxylic acid, either being incorporated as a polymer or subsequently If the basic body of the starting resin is produced in an ionic, for example anicnic or cationic way, by polymerization, the acid component is generally introduced subsequently.

A well-known procedure for subsequent introduction, for example starts with radically or ionisoh polymerized basic bodies with active hydrogen atoms from, and brings the body above 1200C with a mixture of styrene and Maleic anhydride for reaction. This method allows styrene and maleic anhydride to be introduced simultaneously into the starting polymer. Allow other known methods to agitate it to maleic anhydride alone.

e.g.

It is e.g. also possible to introduce carboxy groups in the vicinal position, by reacting the carboxyl group of trimellitic anhydride with ethylene oxide, this reaction product is carefully esterified with acrylic acid and the thus obtained, Unsaturated esters containing anhydride groups by means of interpolymerization incorporated into the resin molecule All of these resins are suitable for the purposes of the invention, provided they only contain at least 50% cycloaliphatic and / or aromatic monomers.

The salt formation takes place through the reaction of the polymerization resins with a reactive compound of a metal from group I of the periodic table or with NH3 or an amine. Some of the free carboxyl groups and / or the carboxyl group-forming derivatives converted into salt form.

Examples of reactive compounds of monovalent cations are preferred However, hydroxides are the acetates, formates, / carbonates and alcoholates of metals of Group I of the Periodic Table, each individually or in a mixture, e.g. from Lithium, sodium and potassium, among the amines used are aliphatic and cycloaliphatic nitrogen compounds, e.g. optionally through at least primary, secondary substituted by an alkyl group or tertiary Amines, and also polyamines, such as ethylenediamine, di-ethylenetriamine, triethylenetetramine or the like, but also called quaternary ammonium bases. The aliphatic remainder These compounds can also contain oxygen in an ethereal bond. In the event of of a cycloaliphatic amine may have the nitrogen atom outside the ring, however also be built into the ring itself. Morpholine is the example of a cycloaliphatic Amine in which the oxygen and amine nitrogen are in the cycloaliphatic ring.

The unsaponified resin does not need to be in solid form before salt formation to be present. So fall resins made by radical telomerization often in aromatic solvents or alcohols. These solutions can then directly with an aqueous or alcoholic solution of the metal, amine or ammonium compound are reacted.

The advantage of a reaction in solution is that it avoids one thermal stress on the resins. The salt formation can also take place in the melt flow, e.g. with salts of volatile carboxylic acids or of carbonic acid. It requires then, however, higher reaction temperatures, with some carbon dioxide being released or carboxylic acid can be withdrawn. However, a thermal depolymerization must be carried out the polymer resins are avoided.

The preferred embodiment of the reaction is the two-phase solution reaction. The unsaponified resin is e.g. in a solvent such as toluene or xylene or a mixture of aromatic solvents, dissolved and for some time) mlt one aqueous solution, the corresponding cation compound treated. After the reaction solvent and water are removed from the saponified resin, e.g., by distillation severed. In the presence of ammonium salts and certain alkylammonium salts is to carry out the drying under gentle conditions in order to form an amide avoid.

In order to increase the molecular weight of the resins used according to the invention, there is the known possibility, the carboxyl groups, if they are not are used for salt formation, too with the help of polyvalent Alcohols such as ethylene glycol, propylene glycol, glycerin, pentaerythritol and the like to esterify. These alcohols - sometimes also monohydric - can be in the system during Eight salt formation are added to each phase, preferably the addition takes place together with the solution of the lye or the salt or amine compound. The amount added varies within wide limits, but in general there will be a shortfall, based on the unreacted carboxyl group units.

The amount of metal compound is chosen so that the degree of neutralization a is between 0.02 and 0.6 after implementation. With unsaponified resins very low viscosity, e.g., from 10 to 50 cP, is the preferred range the degree of neutralization between 0.1 and 0.6. But the starting resin already knows a relatively high viscosity, e.g. over 50 cP (50% in toluene / 20 ° C), then because of the viscosity for toluene printing resins, which increases with the degree of neutralization Degrees of neutralization between 0.02 and 0.3 are preferred.

The starting resin can optionally also be used before the conversion to the salt Rosin has been added. This procedure has the advantage that you can get around unreacted, i.e. monomeric α, β-olefinically unsaturated mono- and / or dicarboxylic acids before salt formation through the known reaction with resin acids with adduct formation can be converted into thermomolecular products. These conversion products can additionally be present in the printing ink or form a mixture with the saponified resins. To achieve a quantitative reaction between rosin and monomeric α, ß-unsaturated To ensure mono- and / or dicarboxylic acid, however, the rosin should before salt formation under the time and temperature conditions required for adduct formation implemented.

The amount of rosin should be at least equivalent to the molar amount Amount of the unreacted free unsaturated acid component of the polymerization resin, but it can also be higher, for example up to a proportion by weight, which corresponds to that of the polymerization resin, since there are no limited quantities experience has shown that converted rosin has the properties of those made from the resin Can improve ink at times.

The resins modified by salt formation used according to the invention stand out compared to resins that do not have any salt groups, by increased or softening points. As a result of the increased softening points, according to the invention the resins used, printing on high-speed printing machines is also possible, wherein the print is dried at an elevated temperature. This is precisely the case with the Use according to the invention of importance. As the comparison tests show, plays The stranding of the carboxyl groups is essential for the state of the art on paper Role, because in most of the comparative tests a strike through was observed. The gloss of the resins used according to the invention is compared with the comparison resins increased by three to four times.

Because of its good viscosity, especially in aromatics, the Use of the resins as binders for printing inks for toluene gravure printing is preferred.

In the following examples, iewells have a yield of 98 until 100 ".

Examples 1) an about 25 to 50 goat solution one by radical Telomerization of styrene and maleic anhydride in a molar ratio of about @: 1 in Presence of cumene as telogen produced telomerizate (softening point 1000C, Viscosity 170 cP, saponification number 101) in xylene is directly linked to that for a degree of neutralization a = 0.1 required amount of 1N sodium hydroxide solution is added and the mixture is refluxed for two hours cooked. The water is passed through a water separator with recirculation of the xylene removed and the remainder of the solvent is distilled off up to 2000C in a water jet vacuum. A clear resin containing salt groups and having a softening point is obtained of 1300C, a viscosity of 490 cP and a degree of neutralization a - 0.1. It is processed as a binder for printing inks, as described below.

2) 150 g of a telomerizate (softening point of 1100 ° C., saponification number 134, viscosity 145 oP), which is produced by the polymerization of styrene, vinyl toluene, a-methylstyrene, Indene and maleic anhydride (molar ratio of the anhydride to the sum of the rest Components = 1: (6-7)) was prepared are dissolved in 150 g of xylene. it will 35.9 ml of 1N potassium hydroxide solution were added and the mixture was heated for two hours. The water is removed with recycling of the xylene and the xylene finally up to 2000C im Distilled off under vacuum. A clear resin with a softening point of 125 ° C. is obtained Viscosity of 400 cP, α is 0.1. Further processing as a printing ink binder takes place as described below.

3) 136.5 g of a styrene-maleic anhydride telomerizate (= 0.3 equivalents) (Molar ratio about 8: 1, softening point 103 ° C., saponification number 123, viscosity 72 cp), 136.5 g of xylene and 3.6 g of 100% sodium hydroxide solution are heated for two hours refluxed. The volatile substances are distilled off and the resin dried at 2050C in vacuo.

The resin has a softening point of 1150C, a viscosity of 710 oP. The degree of neutralization a is 0.3. Its finishing is below described.

4) 300 g of the starting telomerizate according to the example 3 are dissolved in 300 g of xylene. To achieve a degree of neutralization α of 0.1 obtained, 8.1 g of a 32.6% sodium hydroxide solution are added. Additionally be 5 g of propylene glycol were added. After refluxing for two hours, the solution becomes medium distilled off up to 205 ° C in a water jet vacuum. The resin has a softening point from 1120C tmd a viscosity of 118 oP. Its further processing is described below.

5) 136.5 g of the starting telomerizate from Example 3 are in 136.5 8 butanol and 273 g of xylene dissolved. To get a degree of neutralization of 0.1 0.71 8 lithium hydroxide and 25 ml of water are added. After two hours Boiling in the rtioktluß turns water into distillation with recycling of the solvent removed. The solvent is then distilled off up to 20,000 in a water jet vacuum. The resin has the following data: softening point 1060 ° C. and viscosity 78 cP. His Further processing is described below.

6) 200 g of the starting telomerizate from Example 3 are dissolved in 200 g of toluene valid. In order to obtain a degree of neutralization α of 0.1, the cold Solution 3 g of 25% strength aqueous ammonia were added. After careful heating up the boiling point is the water while stirring the solvent by distillation removed. In order to determine the data of the resin, a small part of the resin solution is used carefully dried. A resin is obtained with the following data: Softening point 103 ° C, viscosity 88 cP.

The residue of the toluene solution is used directly for the production of a toluene intaglio printing ink used. Its further processing is described below.

7) 200 g of a styrene-maleic anhydride mixed telomerizate (molar ratio Styrene: maleic anhydride = 8: 1, softening point 113 ° C., viscosity 155 cP, saponification number 125) are dissolved in 200 g of xylene. There are 3.61 g of 33% potassium hydroxide solution and 2.58 g 33% sodium hydroxide solution was added. These added amounts result in a degree of neutralization a u 0.1. After three hours of Koohsn al reflux, the solvent is up to 21000 distilled off in a water jet vacuum. The resulting resin has a softening point of 125 ° C and a viscosity of 543 cP. Its further processing is described below.

8) A telomerizate made from styrene, maleic anhydride, is used as the starting resin and acrylic acid (molar ratio of acid and anhydride: styrene is 1: 8, the molar ratio Acid: anhydride is 3:25. The Telomeriss has a softening point of 990C-, a saponification number of 87 and a viscosity of 157 cP. 350 g of this resin are dissolved in 350 g of xylene and added 54.6 ml of 1N potassium hydroxide solution.

This amount corresponds to a degree of neutralization a of 0.1.

The mixture is treated as described in Example 3. You get a resin with a softening point of 1070 ° C. and a viscosity of 300 cP. Its further processing is described below.

9) A product containing anhydride groups is used as the starting resin, that is brought about by the addition of peroxy at around 1750C Maleic anhydride to a mixed telomerizate produced by free radicals from styrene and vinyl toluene (molar ratio of anhydride to sum of vinyl monomers = 1: about 12) was won. The resin is dissolved in xylene and this solution is distilled with hot Washed water twice to remove the unreacted maleic anhydride. The resin obtained has a softening point of 1180 ° C. and a saponification number of 60 and a viscosity of 55 cP (50% toluene / 20 ° C).

lo) 150 g of the resin from Example 3 together with 30 g of rosin dissolved in 350 g of toluene. When the solution is complete, 120 ml of 1N sodium hydroxide solution are added and the procedure as in Example 3 continued. The resin obtained has the following Data: softening point; 1150C, viscosity 82 cP.

Further processing of the resins To the particular advantages of the invention To show the binders used, these were processed into printing inks that then were checked.

Manufacture of toluene fdrmakfarben From the salt groups containing Resins of Examples 1 to 10 and for comparison of their starting resins is a Toluene solution produced. The solution is allowed to flow for 17 to 20 seconds set in the DIN 4 cup. 14 g of Pigment Red 57 (C.I,) are added to 150 g of this solution a moderately dispersible pigment added. The mixture is 30 minutes long dispersed in a suitable device. To complete the color 'is used with more toluene adjusted to an outflow time of 17 to 20 seconds.

PRINTING TECHNOLOGY TEST The gloss of the resin produced Gravure inks were measured in comparison to the respective starting resins. Observed was also the bleeding through of the colors through the paper.

All printing inks come with drawing spirals in different layer thicknesses applied to 60 g / m2 paper. For the gloss test, a one-off On wear layers obtained with a wet layer thickness of 24 zugeprUtt. the The results are compiled in the following table.

Example Gla n z D u r c h s c h l a g e n modified base resin modified starting resin resin (comparative resin (comparative test) test) 1 22 5 no yes 2 17 5.5 3 18.5 9 4 21.5 8 "5 26 7 6 30 7" "" 7 21 8 "something 8 22 5.5 II yes 9 28.5 6.5 10 21 7

Claims (9)

Claims 1. Non-aqueous printing ink, in particular for toluene gravure printing, with a content of salts of carboxyl group units containing polymerization resins as a binder, which has an average molecular weight of 500 to 5,000 and a saponification number from 10 to 370 and in'denen -a part of the carboxyl group units Salts is implemented, characterized in that 2 to 60 z of the carboxyl groups with cations of Group I of the Periodic System - and / or with optionally substituted ammonium or quaternary ammonium ions with the formation of corresponding ones Salts are implemented. 2. Printing ink according to claim 1, characterized in that the resins a) by polymerization of mono- and optionally diolefins and by subsequent Reaction with components containing carboxyl groups and / or b) through copolymerization of mono- and optionally diolefins with unsaturated carboxyl groups Components have been manufactured. -). Printing ink according to claims 1 or 2, characterized in that the resins a) by subsequent reaction with unsaturated mono- and / or dicarboxylic acids or b) by copolymerization of unsaturated mono- and / or dicarboxylic acids with the olefins. 4. Printing ink according to Claims 1 to 3, characterized in that the resins in the polymerization a) and / or b) have been produced by free radicals, where the monoolefins are preferably vinyl aromatics, 5. Printing color according to claims 1 to 4> characterized in that the resins are salts of vicinal Contain carboxyl group units. 6. Printing ink according to Claims 1 to 5, characterized in that they also have reaction products of Kölophonium with the same unsaturated mono- and / or dicarboxylic acids as incorporated into the resin. 7. Printing ink according to Claims 1 to 6, characterized in that the salts have a viscosity of 10 to 2,000 cP. 8. Printing ink according to Claims 1 to 7, characterized in that the misoh polymerizate by radical copolymerization of a) in steam wrapping produced petroleum fractions or of styrene with b) maleic anhydride has been. 9. Printing ink according to Claims 1 to 8, characterized in that the unsaponified carboxyl group units of the resins at least partially with one or polyhydric alcohols are esterified. lo. Printing ink according to Claims 1 to 9, characterized in that for base resins with a viscosity of 10 to 50 cP the degree of neutralization 0.1 to 0.6 and for starting resins with a viscosity of over 50 cP the degree of neutralization Is 0.02 to 0.3.