EP0263519B1 - Agent for improving the printability of paper and cardboard - Google Patents

Abstract

An agent for improving the printability of paper and board, essentially comprising 50 to 95% by weight of water, and 5 to 50% by weight of a mixture of I. 1 to 50% by weight of (a) an organic quaternary ammonium salt having at least one C8-C22-alkyl group, (b) a mixture of 50 to 99.5% by weight of an organic quaternary ammonium salt and 0.5 to 50% by weight of a saturated or unsaturated C8-C22 -fatty acid, an oxidized wax or a polyglycol having a molecular weight of greater than 4,000, or (c) a mixture of 50 to 99.5% by weight of an organic amine which has been partly neutralized using a mineral acid or a lower carboxylic acid, and 0.5 to 50% by weight of a saturated or unsaturated C8-C33-fatty acid, an oxidized wax or a polyglycol having a molecular weight of greater than 4,000, and II. 50 to 99% by weight of a water-soluble or water-swellable polymer containing anionic groups. In the case of printing papers which are treated with this agent preferably by coating, a reduction in strike-through and show-through of printing ink becomes especially apparent.

Description

The invention has for its object to treat paper and cardboard so that all types of systems containing an organic solvent, for example the dispersed or dissolved in an organic solvent printing ink, coating material or a varnish, especially a low-viscosity gravure ink as little as possible to punch or punch through the paper or cardboard. The less these colors penetrate, the lower the consumption and the nicer the print gloss of the treated surface. The color depth also increases. This problem of knocking the printing ink into the paper is pronounced in all printing processes, but especially in gravure printing processes, since gravure printing inks have to have a significantly lower viscosity compared to other printing inks (high pressure, offset printing). Gravure printing is one of the most widespread types of printing for all types of mass printing. For economic and postal reasons, there has been a tendency for years to reduce the basis weights of such papers. There are limits to this wish, especially with coated gravure paper, but also with natural gravure paper.

In order to have a good level of gravure ink on the paper surface, the line of the coated varieties must have a minimum thickness of about 6.5 - 7 g / m² and page, for double-sided coated gravure paper this results in a coating at 50 g / m² total weight. Base paper of around 36 g / m². From today's perspective, this is a lower limit, since it is only the fibers of the coating base paper that contribute to the physical strength values of the printing paper.

On the other hand, the uncoated rotogravure papers are neither in the whiteness nor in the gloss of those that can be produced Printed matter equivalent to coated gravure papers. In particular, the consumption of gravure printing ink is about 2 1/2 to 3 times that of the coated paper, because the porosity and thus the absorbency of the gravure printing paper is much greater. As a result, punching through and shining through the print on the back is a particular problem with these papers when the basis weight is further reduced.

From EP-A-016 465 a process for the production of coated paper and cardboard is known, in which an aqueous coating slip with particles of at least one aqueous plastic dispersion and inorganic pigments is applied to the coating paper or cardboard and dried.

This coating slip should only penetrate to a small extent into the paper or the cardboard, thus preventing the coating slip from striking through and ensuring a smooth and trouble-free coating process.

The use of hydratable film-forming colloidal clays described in EP-A-00 17 793 succeeded to a certain extent in closing the surface of the uncoated gravure printing paper somewhat and in improving the printability. The rotogravure papers treated in this way, however, are not yet approximately comparable in color with the coated rotogravure papers. However, the use of the hydrated film-forming clays described in EP-A-00 17 793 in coating formulations or as a surface coating is impossible for rheological reasons.

It has now been found that the printing properties, especially the gravure and web offset printing properties of paper, in particular of thin printing paper, but also of cardboard, can be considerably improved if the paper or the cardboard is treated in the mass or on the surface with a mixture, which consists essentially of an aqueous, optionally pigmented dispersion or suspension of organic quaternary ammonium salts and polymers containing anionic groups.

• I. 1 bis 50 Gew.-%
  • a) eines quartären organischen Ammonium-Salzes mit mindestens einer C₈-C₂₂-Alkyl-Gruppe,
  • b) einer Mischung aus 50 bis 99,5 Gew.-% eines quartären organischen Ammonium-Salzes und 0,5 bis 50 Gew.-% einer gesättigten oder ungesättigten C₈-C₂₂-Fettsäure, eines oxydierten Wachses oder eines Polyglykols mit einem Molgewicht über 4 000, oder
  • c) einer Mischung aus 50 bis 99,5 Gew.-% eines mit einer Mineralsäure oder niederen Carbonsäure teilneutralisierten organischen Amins und 0,5 bis 50 Gew.-% einer gesättigten oder ungesättigten C₈-C₂₂-Fettsäure, eines oxydierten Wachses oder eines Polyglykols mit einem Molgewicht über 4 000 sowie
• II. 50 bis 99 Gew.-% eines anionische Gruppen enthaltenden wasserlöslichen oder wasserquellbaren Polymers, wobei bis zu 70 Gew.-% des Polymeren durch Weißpigmente ersetzt sein können.

The invention relates to a means for improving the printability of paper and cardboard as a result of reducing the wrapping of all systems which contain organic solvents, oils and other low to medium-viscosity organic compounds. This means exists essentially from
50 to 95 wt .-% water and
5 to 50 wt .-% of a mixture of

• I. 1 to 50% by weight
  • a) a quaternary organic ammonium salt with at least one C₈-C₂₂-alkyl group,
  • b) a mixture of 50 to 99.5 wt .-% of a quaternary organic ammonium salt and 0.5 to 50 wt .-% of a saturated or unsaturated C₈-C₂₂ fatty acid, an oxidized wax or a polyglycol with a molecular weight 4,000, or
  • c) a mixture of 50 to 99.5 wt .-% of a partially neutralized with a mineral acid or lower carboxylic acid organic amine and 0.5 to 50 wt .-% of a saturated or unsaturated C₈-C₂₂ fatty acid, an oxidized wax or a polyglycol with a molecular weight of over 4,000 as well
• II. 50 to 99% by weight of a water-soluble or water-swellable polymer containing anionic groups, it being possible for up to 70% by weight of the polymer to be replaced by white pigments.

worin R C₈-C₂₂-Alkyl, C₈-C₂₂-Alkenyl oder eine Gruppe der Formel-(A-O)_y-C₈-C₂₂-Alkyl,R₁ C₁-C₄-Alkyl oder Benzyl, R₂ Wasserstoff, C₁-C₂₂-Alkyl, C₁-C₂₂-Alkenyl oder eine Gruppe der Formel -(A-O)_y-B oder der Formel -(A-O)_y-C₈-C₂₂-Alkyl, R₃ Wasserstoff, C₁-C₄-Alkyl oder eine Gruppe der Formel -(A-O)_y-B, A C₁-C₄-Alkylen, B Wasserstoff oder eine Gruppe der Formel -COR, y eine Zahl von 1 bis 25 und X ein Anion bedeuten;

worin X, R, R₁ und R₂ die oben angegebenen Bedeutungen haben;

worin z jeweils eine Zahl von 1 bis 10 bedeutet und X, R₁, A und B die oben angegebenen Bedeutungen haben;

worin p 1 oder 2 bedeutet und X, R und R₁ die oben angegebenen Bedeutungen haben;

worin die Gruppen R₄ gleich oder verschieden sein können und Wasserstoff C₁-C₄-Alkyl, Benzyl oder eine Gruppe der Formel -(A-O)_z-B, m 2 oder 3 und n 0 oder 1 bedeuten und X, R, R₁, A, B und z die oben angegebenen Bedeutungen haben;

worin R₅ Wasserstoff, C₁-C₄-Alkyl oder Benzyl bedeutet und X, R, R₁ und m die oben angegebenen Bedeutungen haben;

worin R₆ OH, NH₂ oder eine Gruppe der Formeln -OCOR oder -NHCOR bedeutet und X, R und R₁ die oben angegebenen Bedeutungen haben;

worin X, R und R₁ die oben angegebenen Bedeutungen haben.Suitable quaternary organic ammonium salts are, in particular, those of the following formulas (1) to (8)

wherein R is C₈-C₂₂-alkyl, C₈-C₂₂-alkenyl or a group of the formula- (AO) _y -C₈-C₂₂-alkyl, R₁ C₁-C₄-alkyl or benzyl, R₂ is hydrogen, C₁-C₂₂-alkyl, C₁- C₂₂-alkenyl or a group of the formula - (AO) _y -B or the formula - (AO) _y -C₈-C₂₂-alkyl, R₃ is hydrogen, C₁-C₄-alkyl or a group of the formula - (AO) _y -B , A is C₁-C₄ alkylene, B is hydrogen or a group of the formula -COR, y is a number from 1 to 25 and X is an anion;

wherein X, R, R₁ and R₂ have the meanings given above;

wherein z each represents a number from 1 to 10 and X, R₁, A and B have the meanings given above;

wherein p is 1 or 2 and X, R and R₁ have the meanings given above;

in which the groups R können can be identical or different and are hydrogen C₁-C₄-alkyl, benzyl or a group of the formula - (AO) _z -B, m 2 or 3 and n are 0 or 1 and X, R, R₁, A, B and z have the meanings given above;

wherein R₅ is hydrogen, C₁-C₄ alkyl or benzyl and X, R, R₁ and m have the meanings given above;

wherein R₆ is OH, NH₂ or a group of the formulas -OCOR or -NHCOR and X, R and R₁ have the meanings given above;

wherein X, R and R₁ have the meanings given above.

Suitable organic amines for component Ic) are those amines on which the quaternary ammonium salts listed above are based. These amines have the following formulas (1ʹ) to (8ʹ), the individual substituents having the same meaning as in the formulas (1) to (8)

Of all the compounds in component Ia), the compounds of the formula 1 are preferred. Also preferred are the partially neutralized amines of the formula 1ʹ in a mixture with C₁₂-C₁₈ fatty acids as component Ic). The following groups are preferred in the compounds of the formulas 1 to 8 and 1ʹ to 8ʹ: R = C₁₂-C₁₈-alkyl or C₁₂-C₁₈-alkenyl R₁ = methyl or ethyl, R₂ = methyl, ethyl, C₁₂-C₁₈-alkyl or C₁₂- C₁₈-alkenyl, A = C₂H₄ or C₃H₆ and n = 1 or 2. Insofar as substituents consist of C₈-C₂₂-alkyl or C₈-C₂₂-alkenyl groups, there are in particular those groups which differ from natural fatty acids and their Derive mixtures such as tallow fatty acid, coconut fatty acid, oleic acid, palmitic acid, stearic acid. Possible anions are, for example, chloride, bromide, sulfate, methosulfate, dimethophosphate, phosphate or anions of organic acids such as acetic acid, propionic acid, trichloroacetic acid, lactic acid, citric acid, tartaric acid, tartronic acid, oxalic acid, malonic acid.

The agent according to the invention preferably contains 15 to 25% by weight of the sum of the two components I and II. The preferred quantitative ratios of the two components I and II to one another are 5 to 15% by weight for component I and accordingly 85 to 95% by weight .-% for component II. Component Ib) preferably consists of 70% by weight of the quaternary ammonium salt and 30% by weight of the other portion (s). The same ratio is preferred for component Ic). For the partial neutralization of the organic amines according to component Ic), 0.05 to 0.5 mol, preferably 0.1 mol, of an acid per 1 mol of organic amine are used. Suitable acids for this purpose are the customary mineral acids and organic carboxylic acids. For component Ic) it has proven to be advantageous to use a non-ionic emulsifier. Instead of only one of the components Ia, b or c can also be used in various mixtures of these individual components.

Suitable polymers (component II) include, for example, polysaccharide derivatives containing anionic groups, such as e.g. Carboxymethyl cellulose, carboxymethyl starch, carboxymethyl guar, xanthan or polymers containing synthetic anionic or polar groups, e.g. Polyacrylates, anionic polyacrylamides, copolymers of acrylic acid and maleic anhydride, of styrene and maleic anhydride or of styrene and acrylic acid or also polyvinyl alcohols and polyvinyl acetates. However, oxidized starch is preferred. Up to 70% by weight of these polymers can also be replaced by the white pigments commonly used in paper production, such as titanium dioxide, kaolin, calcium carbonate. The claimed agents are produced by simply stirring the base batches of the required components.

The agent according to the invention can be added during the paper production in the mixing plant or material center and in an amount of 2 to 8, preferably 5 to 7% by weight, based on the finished paper. The addition can in particular also take place within the filler slurry by first stirring the polymer into the filler slurry and then adding the quaternary organic ammonium compound. This mixture is then added to the fabric. In addition, it is also possible to apply the agent according to the invention to the paper as part of a coating formulation.

However, the agent according to the invention is preferably applied to the surface of the base paper. This is done with the help of suitable devices before calendering. If the paper machine is designed accordingly, the agent according to the invention can also be applied in the dryer section of the machine. After application to the surface, it is dried. The order quantities for the order on the surface are generally 0.1 to 10 g / m², preferably 0.6 to 3 g / m².

The agent according to the invention is suitable for the treatment of all types of paper, such as are required in gravure printing, web offset printing, sheet-fed offset printing and letterpress printing. The agent according to the invention is particularly interesting for gravure and web offset papers. Essentially, two types of paper are suitable for gravure printing, namely the highly filled, satin-coated, mostly wood-containing gravure printing paper in basis weights between 40 to about 80 g / m² (SC paper) and the coated, wood-containing or wood-free, highly satined gravure printing paper in basis weights between 45 and approximately 135 g / m². Web offset printing is usually wood-containing uncoated or coated, so-called LWC paper with basis weights between 40 and 80 g / m². For sheet-fed offset printing, both wood-containing and wood-free papers with basis weights of 60 g / m 2 and up, which are sized or coated on the surface, are generally used. The compounds according to the invention are also of interest for the treatment of paper for letterpress printing (letterpress printing, newspaper printing). It is particularly important here that papers which are treated with the agent according to the invention require less color when printing.

The organic groups in the quaternary ammonium salts and amines prevent further penetration of the printing ink by adsorption of the organic solvent or mineral oil contained in the printing inks and thus penetration of the back of the paper. At the same time, the affinity of the printing ink for paper is improved. The use of the polymer such as oxidized starch is necessary because the organic quaternary ammonium salts alone exert a softening effect on the paper fibers and thus significantly reduce the tear length of the paper. This undesired effect of the quaternary ammonium compound is prevented by salt formation between the quaternary ammonium compound and the polymer. The softening effect and thus the reduction of the tear length is missing.

The advantages which can be achieved with the agent according to the invention on printing papers can be represented as follows: reduction of bleeding through and translucency, increase in color depth or blackness, reduced ink consumption, increase in gloss, reduction of missing dots, increase in conductivity. Web offset printing also showed an improvement in pick resistance. The reduction in ink consumption also makes it easier to deink a paper treated with an agent according to the invention and then printed. The fiber obtained during deinking has a much better whiteness. The described agent also has advantages for carbonless carbonless papers that work with microcapsules. The problem with all of these capsule papers is that approximately half of the capsule content released is sucked back into the dispensing sheet and does not contribute to the color reaction at all. By treating the paper with the agent according to the invention, this sucking back of the capsule contents is reduced and the transfer factor is increased significantly.

In the case of cardboard, which is often overcoated after printing, the coating consumption is reduced by coating with the agent according to the invention.

Examples

The compounds listed in the following table were stirred together in the amounts stated in the form of their aqueous stock solutions, dispersions or suspensions. The mixtures obtained were pasty and showed a pronounced pseudoplastic flow behavior in the cases where kaolin was present. A natural printing paper (40 g / m²) was coated with these mixtures.

Claims (7)

1. An agent for improving the printability of paper and board, essentially comprising
   50 to 95% by weight of water, and
   5 to 50% by weight of a mixture of

   I. 1 to 50% by weight of

   a) an organic quaternary ammonium salt having at least one C₈-C₂₂-alkyl group,

   b) a mixture of 50 to 99.5% by weight of an organic quaternary ammonium salt and 0.5 to 50% by weight of a saturated or unsaturated C₈-C₂₂-fatty acid, an oxidized wax or a polyglycol having a molecular weight of greater than 4,000 or

   c) a mixture of 50 to 99.5% by weight of an organic amine which has been partly neutralized using a mineral acid or a lower carboxylic acid, and 0.5 to 50% by weight of a saturated or unsaturated C₈-C₂₂-fatty acid, an oxidized wax or a polyglycol having a molecular weight of greater than 4,000 and

   II. 50 to 99% by weight of a water-soluble or water-swellable polymer containing anionic groups, it being possible for up to 70% by weight of the polymer to be replaced by white pigments.
2. An agent as claimed in claim 1, wherein the organic quaternary ammonium salt is a compound of the formula (1) to (8)

   

   in which R denotes C₈-C₂₂-alkyl, C₈-C₂₂-alkenyl or a group of the formula -(A-O)_y-C₈-C₂₂-alkyl, R₁ denotes C₁-C₄-alkyl or benzyl, R₂ denotes hydrogen, C₁-C₂₂-alkyl, alkenyl or a group of the formula -(A-O)_y-B or of the formula -(A-O)_y-C₈-C₂₂-alkyl, R₃ denotes hydrogen, C₁-C₄-alkyl or a group of the formula -(A-O)_y-B, A denotes C₁-C₄-alkylene, B denotes hydrogen or a group of the formula -COR, y denotes a number from 1 to 25, and X denotes an anion;

   

   in which X, R, R₁ and R₂ have the abovementioned meanings;

   

   in which z in each case denotes a number from 1 to 10, and X, R₁, A and B have the abovementioned meanings;

   

   in which p denotes 1 or 2, and X, R and R₁ have the abovementioned meanings;

   

   in which the groups R₄ may be identical or different and denote hydrogen, C₁-C₄-alkyl, benzyl or a group of the formula -(A-O)_z-B, m denotes 2 or 3, and n denotes 0 or 1, and X, R, R₁, A, B and z have the abovementioned meanings;

   

   in which R₆ denotes hydrogen, C₁-C₄-alkyl or benzyl and X, R, R₁ and m have the abovementioned meanings;

   

   in which R₆ denotes OH, NH₂ or a group of the formulae -OCOR or -NHCOR, and X, R and R₁ have the abovementioned meanings;

   

   in which X,R and R₁ have the abovementioned meanings.
3. An agent as claimed in claim 1, wherein the organic amine is a compound of the formulae (1') to (8')

   
4. An agent as claimed in claim 1, wherein component I is distearyldimethylammonium chloride.
5. An agent as claimed in claim 1, wherein component I comprises a mixture of partly neutralized stearylamine and stearic acid.
6. An agent as claimed in claim 1, wherein component II contains up to 70% by weight of titanium dioxide, kaolin and/or calcium carbonate.
7. A process for improving the printability of paper, wherein the agent as claimed in claim 1 is incorporated into the paper material or applied to the surface of the paper.