DE10233533A1 - Novel polyvinyl acetates and their use - Google Patents

Abstract

The present invention relates to the use of at least one polyvinyl acetal as a binder for aqueous dispersions, the polyvinyl acetal being converted by reacting at least one polymer (A), DOLLAR A or DOLLAR A a.) From 1.0 to 99.9% by weight of structural units of the formula ( 1) DOLLAR F1 DOLLAR A b.) 0 to 99.0% by weight of structural units of the formula (2) DOLLAR F2 DOLLAR A c.) 0 to 70.0% by weight of structural units of the formula (3) DOLLAR F3 DOLLAR A in each case based on the total weight of the polymer (A), DOLLAR A is obtainable with at least one compound (C) of the formula (5) DOLLAR F4 DOLLAR A wherein the polyvinyl acetal, based on the total number of structural units of the formula (1), in the polymer (A) contains between 65 and 99 mol% of structural units of the formula (1). In this context, the DOLLAR AR · 1 ·, R · 2 ·, R · 3 ·, R · 4 ·, R · 5 ·, R · 6 ·, R · 9 · and R · 10 · radicals are defined as described ,

Description

The present invention relates to the use of polyvinyl acetals as binders for aqueous dispersions.

The use of polyvinyl acetals as binders for dispersions, such as lacquers, printing inks and ceramic molding compositions, has long been known. The commonly used products, the production of which is, for example, in EP 0,174,479 and DE 35 26 314 are polyvinyl butyrals which are prepared from fully hydrolyzed polyvinyl alcohols and whose degree of acetalization is above 20%. Because of the degree of acetalization described, the polyvinyl butyrals are water-insoluble.

The areas of application of polyvinyl acetal There are many different types of paint: in addition to car refinish paints, stove enamels, shop primers, wash primers and adhesive varnishes also insulating coatings on tar, nicotine etc., plastic lacquers, nitrocellulose lacquers and paper varnishes with polyvinyl acetals.

Polyvinyl acetal is also used in the production of dispersions such as pigment concentrates, slip and other preparations in which organic or inorganic Solids in a liquid Medium must be dispersed and stabilized.

Printing inks are made according to the specialist known methods. To do this, either the pigments with the possibly solved Binder is ground with the addition of additives or it is Prefabricated pigment pastes are used and with solvent, the other Can contain binders and additives, diluted. Polyvinyl acetals, especially Polyvinyl butyrals are used for used the packaging printing. Because generally polyvinyl butyrals in its composition of recommendation XL of the Federal Institute for Health Consumer protection and veterinary medicine (BgVV) and the FDA § 175.300 can correspond printing inks produced therewith for printing on food packaging be used. Usually become insoluble in printing inks Pigments used with one or more binders and if necessary, additives in a solvent or mixed solvents be dispersed. For special applications such as ink jet inks, also become soluble Dyes used.

The printing inks have good adhesion properties on organic and inorganic substrates and are therefore suitable for printing on polyolefin, Metal, cellulose acetate, polyamide and polystyrene foils. by virtue of These good adhesion properties use polyvinyl acetals for interlayer printing. If necessary, the liability on difficult surfaces Addition of an adhesion promoter can be improved. If necessary plasticizers known to those skilled in the art are also added to the colors to make it more flexible. The printing inks are characterized by low Solvent retention, good flow behavior as well good water and cold resistance out. The polyvinyl butyrals used have good solubility in alcohols and other organic solvents and a wide range compatibility with blending resins and additives.

A general problem with the described Applications is the use of organic solvents. In times aggravating Legislation regarding the emission of volatile organic compounds gain aqueous dispersions, such as Varnishes, printing inks and ceramic molding compounds are becoming increasingly important. Polyvinyl butyrals with a degree of acetalization of over 20% have the disadvantage that they are not water-soluble. So you divorce for the described applications.

The property of water solubility depends on polyvinyl acetals on the molecular weight and on the type of functional groups or of the aldehyde used for the acetalization. Accordingly changes also the degree of limit acetalization, above which a polyvinyl acetal insoluble in water (C.A. Finch, "Polyvinyl alcohol ", John Wiley & Sons, 1992).

As polymers that are soluble in water and which are used as binders and stabilizers for dispersions, can such connections are used that have a sufficient number of polar atomic groups in the polymer chain, so that solubility is achieved in water. These include for example polyvinyl alcohols, cellulose ethers, gelatin and others water-soluble Polymers. A disadvantage of these binders is their poor dispersing effect, what inadequate application properties, such as the defective Gloss and the poor stability of printing inks, expressed comes.

The aim of the present invention was therefore to make better binders for the production of aqueous Dispersions available to ask, especially in comparison with the conventional Binders for aqueous Dispersions have an improved dispersing effect.

The present invention was also the task of specifying binders for aqueous dispersions, which the wetting of the dispersed substances, in particular of Pigments, significantly improve.

An object of the present invention was also to be seen in giving binders for aqueous dispersions, which the stability the dispersion compared to conventional systems. there should the watery Dispersions when setting one if possible slight increase in viscosity and none or one if possible late gelation the dispersion at if possible show high total solids.

It was also an object of the present invention to make aqueous printing inks and varnishes accessible Chen, which have a significantly higher gloss than can be expected using the conventional water-soluble binders.

Another was a task of the present invention to be seen in binders for aqueous slip formulations provide that compared to conventional aqueous Recipes should be easier to process and preferably one should lead to improved wetting of the dispersed substances. Ceramic green foils with increased flexibility were particularly sought after.

These are solved as well as others tasks not explicitly mentioned, but from the ones discussed here cohere are easily derivable or accessible through the use of polyvinyl acetals with all the features of the present claim 1. Appropriate modifications this procedure is referred back to claim 1 dependent claims under protection.

• a.) 1,0 bis 99,9 Gew.-% Struktureinheiten der Formel (1)
  
  worin R¹ Wasserstoff oder Methyl bedeutet,
• b.) 0 bis 99,0 Gew.-% Struktureinheiten der Formel (2)
  
  worin R² Wasserstoff oder einen Alkylrest mit 1 bis 6 Kohlenstoffatomen darstellt,
• c.) 0 bis 70,0 Gew.-% Struktureinheiten der Formel (3)
  
  worin R³, R⁴, R⁵ und R⁶, jeweils unabhängig voneinander Reste mit einem Molekulargewicht im Bereich von 1 bis 500 g/mol sind,

jeweils bezogen auf das Gesamtgewicht des Polymers (A) enthält,
mit mindestens einer Verbindung (C) der Formel (5) erhältlich ist,

worin R⁹ und R¹⁰ jeweils unabhängig voneinander Wasserstoff, COOH, eine Alkylgruppe mit 1 bis 10 Kohlenstoffatomen oder eine gegebenenfalls substituierte Arylgruppe mit 6 bis 12 Kohlenstoffatomen sind,
wobei das Polyvinylacetal bezogen auf die Gesamtzahl an Struktureinheiten der Formel (1) im Polymer (A) zwischen 65 und 99 mol-% Struktureinheiten der Formel (1) enthält, gelingt es auf nicht ohne weiteres vorhersehbare Weise, Bindemittel für wässrige Dispersionen mit einer guter Dispergierwirkung bereitzustellen, die gegenüber den konventionellen, wasserlöslichen Bindemitteln, wie beispielsweise Polyvinylalkohole, deutlich verbessert ist.The fact that at least one polyvinyl acetal is used as a binder for aqueous dispersions, which by reacting at least one polymer (A),
the

• a.) 1.0 to 99.9% by weight of structural units of the formula (1)
  
  where R ^{1 is} hydrogen or methyl,
• b.) 0 to 99.0% by weight of structural units of the formula (2)
  
  in which R ^{2 represents} hydrogen or an alkyl radical having 1 to 6 carbon atoms,
• c.) 0 to 70.0% by weight of structural units of the formula (3)
  
  wherein R ³ , R ⁴ , R ⁵ and R ⁶ , each independently of one another, are residues with a molecular weight in the range from 1 to 500 g / mol,

each based on the total weight of the polymer (A),
is obtainable with at least one compound (C) of the formula (5),

wherein R ⁹ and R ^{10 are} each independently hydrogen, COOH, an alkyl group with 1 to 10 carbon atoms or an optionally substituted aryl group with 6 to 12 carbon atoms,
where the polyvinyl acetal, based on the total number of structural units of the formula (1) in the polymer (A), contains between 65 and 99 mol% of structural units of the formula (1), it is possible to predict binders for aqueous dispersions with a good quality To provide dispersing effect, which is significantly improved over the conventional, water-soluble binders, such as polyvinyl alcohols.

• – Die Benetzung der dispergierten Substanzen, insbesondere von Pigmenten, wird erfindungsgemäß deutlich verbessert.
• – Die Verwendung der vorstehend genannten Polyvinylacetale führt zu wäßrigen Dispersionen mit verbesserter Stabilität gegenüber herkömmlichen Systemen. Diese ist insbesondere bei der Lagerung der wässrigen Dispersionen von Vorteil, da hier nur ein vergleichsweise geringerer Viskositätsanstieg und keine bzw. eine deutlich spätere Gelierung der Dispersion zu beobachten ist. Die resultierenden Druckfarben und Lacke weisen einen deutlich höheren Glanz auf, als dies von bekannten wasserlöslichen Bindemitteln zu erwarten ist.

At the same time, a number of further advantages can be achieved by the procedure according to the invention:

• - The wetting of the dispersed substances, in particular pigments, is significantly improved according to the invention.
• - The use of the above-mentioned polyvinyl acetals leads to aqueous dispersions with improved stability compared to conventional systems. This is particularly advantageous when storing the aqueous dispersions, since only a comparatively small increase in viscosity and no or significantly later gelation of the dispersion can be observed. The resulting printing inks and varnishes have a significantly higher gloss than can be expected from known water-soluble binders.

Furthermore, when using the described polyvinyl acetals in the field of ceramics the flexibility of ceramic green films across from the use of polyvinyl alcohol increased, compared to the processing to other water-based binders considerably easier. The Demand for improved wettability of inorganic or organic powders by aqueous Binder can therefore be met become. The present invention relates to the use at least one polyvinyl acetal, which by reaction at least of a polymer (A) with at least one compound (C) is available.

• a.) 1,0 bis 99,9 Gew.-% Struktureinheiten der Formel (1)
  
• b.) 0 bis 99,0 Gew.-% Struktureinheiten der Formel (2)
  
• c.) 0 bis 70,0 Gew.-%, vorzugsweise 0,01 bis 70,0 Gew.-%, Struktureinheiten der Formel (3)
  

The polymer (A) contains based on its total weight

• a.) 1.0 to 99.9% by weight of structural units of the formula (1)
  
• b.) 0 to 99.0% by weight of structural units of the formula (2)
  
• c.) 0 to 70.0% by weight, preferably 0.01 to 70.0% by weight, structural units of the formula (3)
  

The respective structural units Naturally different from one another, in particular within the scope of the present Invention the structural unit of formula (3) not the structural units of the formula (1) or (2).

The radical R ¹ each independently represents hydrogen or methyl, preferably hydrogen.

The radical R ² denotes hydrogen or an alkyl radical with 1 to 6 carbon atoms, preferably an alkyl radical with 1 to 6 carbon atoms, advantageously a methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl -, tert-butyl, n-pentyl or an n-hexyl group, advantageously a methyl or an ethyl group, in particular a methyl group.

The radicals R ³ , R ⁴ , R ⁵ and R ⁶ are each, independently of one another, radicals with a molecular weight in the range from 1 to 500 g / mol, advantageously hydrogen, an optionally branched, aliphatic or cycloaliphatic radical with 1 to 16 carbon atoms, which, if appropriate may contain one or more carboxylic acid, carboxylic acid anhydride, carboxylic acid ester, carboxylic acid amide and / or sulfonic acid groups.

Particularly preferred structural units of the formula (3) are derived from straight-chain or branched olefins having 2 to 18 carbon atoms, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, (meth) acrylamides and / or ethylene sulfonic acid. Here, olefins, in particular those with a terminal CC double bond, which preferably have 2 to 6 carbon atoms, in particular ethylene, have proven to be very particularly favorable. Furthermore, structural units (3) which are derived from acrylamidopropenylsulfonic acid (AMPS) also lead to very particularly advantageous He according to the invention gebnissen.

The total number of structural units of formula (2) is preferably in the range from 0.1 to 40 mol%, expediently in the range from 0.5 to 25.0 mol%, in particular in the range from 1.0 up to 15.0 mol%, each based on the total number of structural units of the formula (1) and (2). According to a first preferred embodiment of the present invention uses a polymer (A) which is related to the total number of structural units of the formula (1) and (2) Contains 1.0 to 2.0 mol% of structural units of the formula (2). According to one second preferred embodiment In the present invention, a polymer (A) is used which based on the total number of structural units of the formula (1) and (2) contains 3.0 to 7.0 mol% of structural units of the formula (2). According to one third preferred embodiment of the In the present invention, a polymer (A) is used which is related to the total number of structural units of the formula (1) and (2) Contains 10.0 to 15.0 mol% of structural units of the formula (2).

According to another particularly preferred embodiment the present invention includes this Polymer (A), in each case based on its total weight,> 50.0% by weight, advantageously> 60.0% by weight, advantageously> 70.0% by weight, in particular> 80.0% by weight structural units of the formula (1) and / or (2). Particularly advantageous results can be achieved can be achieved with polymers (A) which, based in each case on their total weight, are> 85.0% by weight, expediently> 90.0% by weight, advantageously> 95.0% by weight, in particular> 99.0 % By weight of structural units of the formula (1) and / or (2).

Within the scope of the present invention the polymer (A) can be a syndiotactic, isotactic and / or have atactic chain structure. Furthermore, it can be used both as random as well as block copolymer.

According to the invention, the viscosity of the polymer (A) is of secondary importance Meaning, in principle, can both low molecular weight and high molecular weight polymers (A) are used become. Nevertheless, it has been within the scope of the present invention as very cheap proven that the polymer (A) has a viscosity in the range of 1 to 70 mPas, preferably in the range from 2 to 40 mPas, in particular in the range from 3 to 30 mPas, (measured as a 4% by weight aqueous solution according to Hoppler at 20 ° C, DIN 53015).

The preparation of those to be used according to the invention Polymers (A) can be prepared in a known manner in a two-stage Procedure. In a first step, the corresponding one Vinyl esters in a suitable solvent, usually water or an alcohol, such as methanol, ethanol, propanol and / or Butanol, using a suitable radical initiator, radical polymerized. The polymerization becomes radical in the presence copolymerizable monomers carried out, so you get the corresponding vinyl ester copolymers.

The vinyl ester (co) polymer is then in a second step, usually by transesterification with methanol, saponified, the degree of saponification being determined in a manner known per se, for example by varying the catalyst concentration, the reaction temperature and / or the reaction time can. For further details will be on the common Specialist literature, especially on Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition on CD-Rom Wiley-VCH, 1997, Keyword: Poly (Vinyl Acetals) and referenced references there.

According to the invention, the compound (C) has the formula (5)

The radicals R ⁹ and R ¹⁰ are each independently hydrogen, COOH, an alkyl group with 1 to 10 carbon atoms or an aryl group with 6 to 12 carbon atoms. These alkyl and aryl radicals can be substituted with one or more carboxyl, hydroxyl, sulfonic acid groups and / or halogen atoms, such as fluorine, chlorine, bromine, iodine. The preferred compounds (C) include formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, 2-ethoxybutyraldehyde, paraldehyde, 1,3,5-trioxane, capronaldehyde, 2-ethylhexanal, pelargonaldehyde, 3,5,5- Trimethylhexanal, 2-formylbenzenesulfonic acid, acetone, ethyl methyl ketone, butyl ethyl ketone and / or ethyl hexyl ketone. According to a further preferred embodiment, glyoxylic acid HCO-OOOH is used as compound (C).

According to the invention, the use of aldehydes, ie of compounds of the formula (5) with R ⁹ = hydrogen and R ¹⁰ = hydrogen, a methyl, ethyl, n-propyl or an isopropyl group, preferably formaldehyde and / or n-Butyraldehyde, especially of n-butyraldehyde, has proven particularly useful.

• A.) 50,0 bis 99,99 Gewichtsteilen mindestens eines Polymers (A) und
• B.) 0,01 bis 50,0 Gewichtsteilen mindestens einer Hydroxyverbindung (B) enthalten, wobei die Summe der Gewichtsteile aus A.) und B.) vorzugsweise 100 Gewichtsteile ergibt.

In the context of a particularly preferred embodiment of the present invention, the reaction of the at least one polymer (A) with the at least one compound (C) is carried out in the presence of at least one hydroxy compound (B). The use of mixtures of polymer (A) and hydroxy compound (B) is particularly favorable here

• A.) 50.0 to 99.99 parts by weight of at least one polymer (A) and
• B.) 0.01 to 50.0 parts by weight of at least one hydroxy compound (B), the sum of the parts by weight from A.) and B.) preferably giving 100 parts by weight.

According to this embodiment of the present invention, the hydroxy compound (B) satisfies the formula (4)

The radical R ⁷ denotes hydrogen or an alkyl radical with 1 to 6 carbon atoms, preferably a methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n- Pentyl or an n-hexyl group, especially a methyl group. According to a very particularly preferred embodiment of the present invention, the radical R ^{7 is} hydrogen.

The radicals R ^{7 can} each be selected independently of one another, ie each repeating unit -CHR ⁷ -CH ₂ O- can have a different radical R ⁷ . Consequently, the above definition of the hydroxy compound (B) encompasses both polyethylene glycol (monoether) and polypropylene glycol (monoether) and polyethylene glycol-co-propylene glycol (monoether). The latter can have both a statistical and a block-like structure.

The radical R ⁸ denotes hydrogen or an alkyl radical with 1 to 10 carbon atoms, preferably a methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n- Pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or an n-decyl group, especially a methyl group. According to a very particularly preferred embodiment of the present invention, the radical R ^{8 represents} hydrogen.

n is a number greater than or equal to 2, preferably a number in the range from 2 to 1000, advantageously in Range from 3 to 300 advantageously in the range from 3 and 25, particularly preferably in the range from 3 to 10, in particular in the range from 4 to 6. Furthermore, you can particularly cheap Results are obtained when n is a number in the range from 10 to 20, in particular in the range from 12 to 15.

The structure of polyvinyl acetals according to this particularly preferred embodiment the present invention is not yet available Completely clarified. Nevertheless, the current results suggest that the hydroxy compound (B) is covalently bound to the polymer, as it is - in contrast to conventional Plasticizers - not more from the polymer, for example by means of an extraction (e.g. B. by Soxhlet extraction), isolates. However, it goes without saying that the teaching of the present Invention is not limited to this interpretation.

The polyvinyl acetal to be used according to the invention is characterized in that it is based on the total number Structural units of the formula (1) in the polymer (A) between 65 and 99 mol%, preferably between 70 and 90 mol%, structural units of formula (1) contains. For this purpose, the proportions of the starting compounds (A), (C) and optionally (B) are preferably chosen such that one per mole of hydroxyl groups, the polymer (A) and - if present - the Hydroxy compound (B) contained in total, 0.0005 to 0.35 mol, preferably 0.0005 to 0.26 mol, the compound (C) uses.

In addition, the connections (B) and (C) preferably in a molar ratio of compound (C) / compound (B) greater than or equal to one used.

Implementation of the starting compounds (A), (C) and optionally (B) are preferably carried out in at least an inert solvent, the term “inert Solvent "for such Solvent, which does not follow the course of the under the respective reaction conditions desired Disrupt acetalization reaction or even prevent. A particularly useful solvent in this context is water.

The reaction is also conveniently carried out in the presence of acidic catalysts. Suitable acids include both organic acids, such as acetic acid as well as mineral acids like Hydrochloric acid, sulfuric acid and / or nitric acid, where the use of hydrochloric acid, Sulfuric acid and / or nitric acid especially proven in technology Has. The implementation the reaction is preferably carried out in such a way that a mixture from components (A) and optionally (B) in aqueous solution submitted, the compound (C) enters this solution and then the acid catalyst added dropwise. According to one another preferred embodiment the present invention has also proven to be advantageous the components (A) and optionally (B) in aqueous solution, the acidic Catalyst in this solution stir and subsequently to start the reaction by adding the compound (C).

The reaction temperature can be varied over a wide range, but frequently the temperature is in the range from -20.0 ° C to 100.0 ° C, preferably in the range from 0.0 ° C to 80.0 ° C. The same applies to the pressure at which the implementation is carried out. The reaction can take place both at negative pressure and at Overpressure take place. However, it is preferably carried out at normal pressure. Although the reaction can also take place in air, it has proven advantageous in the context of the present invention to carry out the reaction under a protective gas atmosphere, preferably nitrogen and / or argon.

Alternative manufacturing methods of to be used according to the invention Polymers are obvious to the person skilled in the art. For example, it is possible, Instead of the compound (C) use compounds that are under the selected Reaction conditions Release compounds (C). These include a. cyclic trimers of aldehydes and acetals of aldehydes or Ketones.

Furthermore, it is according to one particularly preferred embodiment the present invention also possible, the polymer (A) first by Partial reaction with a certain amount of compound (C) to acetalize, then admix at least one hydroxy compound (B) and the resulting mixture with another amount of compound (C) implement.

Within the scope of the present invention the polyvinyl acetal described above is used as a binder for aqueous dispersions used. The terms “binder” and “aqueous dispersion” are best for the person skilled in the art known.

Binders are substances combine the same or different types of substances, whereby the setting of the substances by physically drying the aqueous ones Dispersion takes place. For paints and varnishes that are in the frame a particularly preferred embodiment In the foreground of the present invention are binders according to DIN 55945 (12/1988) defines and characterizes the non-volatile person (s) Portions without pigment and filler, but including Plasticizers, drying agents, etc. non-volatile auxiliaries. task the binding agent is the binding of the pigment particles to one another and with the underground.

The term "dispersions" stands according to DIN 53900 (July 1972) for a disperse system of several phases, one of which is continuous (Dispersant) and at least one other is finely divided (dispersed phase, dispersant).

The dispersant is in the present Case a solvent or mixture containing water. Solvents are labeled liquids with a dynamic viscosity especially at 25 ° C and at normal pressure (101325 Pa) in the range of 0.1 to 10 mPa s.

The dispersant can vary depending on the application freely selected become. It includes, for example, colorants (pigments), in particular for printing inks, Corrosion-inhibiting substances, especially for anti-corrosion agents, and clay minerals, especially for slip formulations.

Within the scope of the present invention the dispersant is expedient in the respective amounts used in the dispersant, in particular in water, not completely soluble. The solubility is at 25 ° C preferably less than 1 g per 100 g of dispersant in the dispersant, expediently 0.1 g per 100 g, dispersant. The water solubility is preferably at 25 ° C less than 1.0 g per 100 g water, in particular 0.1 g per 100 g Water.

Furthermore, the dispersant is preferred a solid, i.e. H. it particularly shows at 25 ° C and Normal pressure (101325 Pa) a dynamic viscosity greater than 10 mPa s, expediently greater than 100 kPas s on.

[σ₁ bzw. σ₂ = Oberflächenspannung des Festkörpers bzw. der Flüssigkeiten, γ_{1, 2} = Grenzflächenspannung fest/flüssig, ? = Randwinkel od. Kontaktwinkel) (s. Römpp Lexikon Chemie – Version 2.0, Stuttgart/New York: Georg Thieme Verlag 1999) – Stichwort: Benetzung].According to the invention, the dispersion of the particles to be dispersed is facilitated by the polyvinyl acetals described above by lowering the interfacial tension between the two components, that is to say bringing about wetting. The wetting tendency can be derived from the determination of the contact angle that the liquids form with the solid surface:

[σ ₁ or σ ₂ = surface tension of the solid or liquids, γ _{1, 2} = interfacial tension solid / liquid,? = Contact angle or contact angle) (see Römpp Lexikon Chemie - Version 2.0, Stuttgart / New York: Georg Thieme Verlag 1999) - keyword: wetting].

The composition of the aqueous Dispersion can be used in the context of the present invention depending on the application freely selected if it contains water. Still have watery Dispersions based on their total weight are preferably more than 10% by weight, expediently more than 20% by weight, in particular more than 30% by weight, at least of a solvent included, especially according to the invention proven.

Furthermore, the solvent (mixture) based on the total amount of solvent preferably at least 10% by weight, expediently at least 20 % By weight, in particular at least 30% by weight, of water. Especially beneficial results can achieved according to the invention if the solvent (mixture) based on the total amount of solvent at least 40% by weight, expediently at least 50% by weight, in particular at least 60% by weight, of water is.

The manufacture of the aqueous Dispersion can be carried out in a manner known per se, e.g. B. electrochemically, electrically or mechanically (by grinding, using ultrasound, etc.). It is preferably carried out mechanically.

Although those described above Polyvinyl acetals especially as binders for aqueous dispersions are suitable, it may be appropriate in individual cases, further co-binders to be used, for example, to pigment wetting or dispersing or improve liability. Therefore, under a special preferred embodiment of the present invention at least one further co-binder used. Suitable co-binders include all for aqueous dispersions known binders, preferably organic binders, in particular Polyvinyl alcohols, cellulose ethers, gelatin, polyvinyl pyrrolidones, Polyvinyl sulfates, polyacrylates, polyacrylamides, maleic acid-styrene copolymers and other water soluble Polymers. According to the invention the co-binder a water solubility at 20 ° C of at least 1.0 g co-binder per 100 g of pure water.

The amounts of co-binder can vary arbitrarily chosen after application become. Nevertheless, according to the invention, it has proven to be particularly favorable that the proportion of all co-binders based on the total mass of all binders used in the range from 0.1 to 95.0% by weight , preferably in the range from 0.1 to 80.0% by weight, expediently in the range from 0.1 to 60.0% by weight, in particular in the range from 0.1 to <50.0 % By weight. Particularly advantageous results can be achieved if the proportion of all co-binders is based on the total mass all binders used in the range from 0.1 to 40.0% by weight, preferably in the range from 0.1 to 25.0% by weight, expediently in the range from 0.1 to 10.0% by weight, in particular in the range from 0.1 to 5.0% by weight.

As part of another particularly preferred embodiment The present invention relates to all co-binders on the total mass of all binders used in the range of 50.0 to 95.0% by weight, preferably in the range from 70.0 to 95.0% by weight, expediently in the range from 80.0 to 95.0% by weight, in particular in the range from 90.0 and 95.0% by weight.

In a third particularly preferred embodiment of the present invention includes the aqueous Dispersion no co-binders.

Possible Areas of application of the aqueous Dispersion are for the person skilled in the art on the basis of the present description directly obviously. It is particularly suitable for those applications for aqueous dispersions containing conventional, water-soluble binders, in particular for polyvinyl alcohols, cellulose ethers, Gelatin, polyvinyl pyrrolidones, polyvinyl sulfates, polyacrylates, Polyacrylamides and maleic acid-styrene copolymers, pre-drawn are.

As part of a particularly preferred embodiment The present invention uses the aqueous dispersion for manufacture a printing ink used. Printing inks denote liquid, pasty or powdery colorant preparations, which are used in printing machines. That in different Printing process material to be printed can generally be absorbent or non-absorbent, flat (e.g. paper, cardboard, leather, foils), cylindrical or conical (e.g. cans or other hollow bodies). In terms of the special circumstances of printing on textiles, reference is made to the specialist literature - keyword "textile printing".

• – Farbmitteln (Pigmenten einschließlich Füllstoffen oder Farbstoffen, bei Leuchtdruckfarben auch fluoreszierend), –
• – Bindemitteln (meist (Druck-)Firnisse genannt) und
• – Zusatzstoffen (z.B. Trockenstoffen, Verdünnungsmitteln, Wachsdispersionen, Katalysatoren bzw. Initiatoren für die Strahlungstrocknung).

The printing inks are very finely divided mixtures or solutions that are composed of

• - colorants (pigments including fillers or dyes, also fluorescent in the case of fluorescent printing inks),
• - binders (usually called (printing) varnishes) and
• - additives (e.g. drying agents, diluents, wax dispersions, catalysts or initiators for radiation drying).

The composition of if necessary after The inks prepared using the flushing process are not only from Printing process dependent (High, low, low and Printing), but especially of the substrate and the requirements the print result in terms of appearance (color tone, transparency or opacity, shine, Fluorescence) and physical properties (water, fat, solvent, Abrasion resistance, lamination and overpainting ability, etc.). One again today current point of view is - at Recycling - the to be able to remove the applied ink if necessary (de-inking).

• – Erwin Schulz, "Flexodruck von A bis Z", Polygraph Verlag, Frankfurt am Main, 1987 Nachschlagewerk zum Thema „Flexodruck"
• – The Printing Ink Manual" Chapman & Hall detaillierte Informationen zu den Ausgangsmaterialien und gängigen Formulierungen
• – Chris Williams „Printing Ink Technology" PIRA detaillierte Informationen zur Drucktechnologie

For further details, reference is made to the current specialist literature, in particular to the following publications, the disclosure of which is hereby expressly incorporated by reference:

• - Erwin Schulz, "Flexo printing from A to Z", Polygraph Verlag, Frankfurt am Main, 1987 reference book on "Flexo printing"
• - The Printing Ink Manual "Chapman & Hall detailed information on the starting materials and common formulations
• - Chris Williams "Printing Ink Technology" PIRA detailed information on printing technology

According to a further, particularly preferred embodiment of the present invention, the aqueous dispersion is used to produce an anti-corrosion agent. In this context, anti-corrosion agents are understood to mean all materials suitable for passive anti-corrosion protection (see DIN 50900 Part 1 (April 1982)), with which objects, apparatus, systems, components, etc. are covered (Coatings, protective layers, foils, etc.) can be used to protect them against the attack of corrosive media (corrosion).

Leave solid anti-corrosion agents sticking and wrapping (tapes, Foils), rolling, pressing and the like or by melting (e.g. Enamels for Protective skins) and apply spinal sintering; pasty anti-corrosion agents Spread, liquid or solved Corrosion protection agents by dipping, painting, spraying, spraying, electrophoretic et al electrochemical processes. This way you get up those to be protected surfaces all types of coatings on both the base coats on red lead, zinc dust, zinc chromate, iron oxide, phosphate, Molybdate, borate-based as well as the top coats on oil, alkyd resin, Coumarone resin, chlorinated rubber, phenol formaldehyde resin, vinyl polymer, Nitrocellulose, bitumen and pitch based, still reaction primer or epoxy resin, polyurethane, polyester and acrylic resin based primer as well as protective skins (Film coatings). Many metals become oxide. protective coatings by anod. Oxide. produced or reinforced, chromate or phosphate layers (e.g. on iron) by precipitation generates and protective coatings from foreign metals applied by electrodeposition or electroless processes.

• – A. van Oeteren, "Korrosionsschutz durch Beschichtungsstoffe", Band 1 und 2, Carl Hanser Verlag, München, Wien detaillierte Informationen zu den Beschichtungsstoffen sowie den Applikationsverfahren
• – Hans Kittel, "Lehrbuch der Lacke und Beschichtungen ", Verlag W.A. Colomb, Berlin, Oberschwandorf, 1976 detaillierte Informationen zu gängigen wässrigen Korrosionsschutz-Formulierungen
• – Ulrich Zorll (Hrsg.), "Lehrbuch der Lacktechnologie", Vincentz Verlag, Hannover, 1998 detaillierte Informationen zu den Rohstoffen, gängigen Formulierungen, Herstellverfahren und Applikationsmöglichkeiten

For further details, reference is made to the current specialist literature, in particular to the following publications, the disclosure of which is hereby expressly incorporated by reference:

• - A. van Oeteren, "Corrosion protection through coating materials", Vol. 1 and 2, Carl Hanser Verlag, Munich, Vienna detailed information on the coating materials and the application methods
• - Hans Kittel, "Textbook of paints and coatings", publisher WA Colomb, Berlin, Oberschwandorf, 1976 detailed information on common aqueous corrosion protection formulations
• - Ulrich Zorll (ed.), "Textbook of paint technology", Vincentz Verlag, Hanover, 1998 detailed information on raw materials, common formulations, manufacturing processes and application options

According to a third, particularly preferred embodiment of the present invention, the aqueous dispersion is used to produce a slip formulation. These usually contain dispersed clay minerals, such as clay and / or kaolin, in particular kaolinite [Al ₂ (OH) ₄ (Si ₂ O ₅ ) or Al ₂ O ₃ ⋅2SiO ₂ ⋅2H ₂ O] and / or illite [K _{0, 7} Al ₂ (OH) ₂ (Si _3.3 Al _0.7 O ₁₀ )]. While the kaolins, mostly from primary deposits, have to be freed of coarse fractions before processing by sludge, the clays, which have already been sludged from nature, can often be processed as extracted from the earth.

In addition to the clay minerals included Slip formulations, if appropriate, further additives, such as, for example Lean agent to reduce shrinkage during drying and fire (e.g. quartz, sand, ground fired clay = chamotte), flux to lower the sintering temperature (e.g. feldspar) and, if necessary colorants (Metal oxides, see e.g. Römpp Lexikon Chemie - Version 2.0, Stuttgart / New York: Georg Thieme Verlag 1999 - keyword “ceramic Pigments ") included.

• – Reh (Hrsg.), "Keramiker Jahrbuch 1998", Bauverlag, Wiesbaden, 1997 detaillierte Informationen zum Verarbeiten von Schlicker, insbesondere zum Foliengießen, sowie zum Einsatz von wasserlöslichen Bindemitteln (s. weiterführender Literaturangaben)
• – Adv. Mater. 4 (1992), 73-81 detaillierte Informationen zu den einzelnen Schlickerkomponenten und zum Einsatz von wasserlöslichen Bindemitteln

For further details, reference is made to the current specialist literature, in particular to the following publications, the disclosure of which is hereby expressly incorporated by reference:

• - Reh (ed.), "Keramiker Jahrbuch 1998", Bauverlag, Wiesbaden, 1997 detailed information on the processing of slip, especially for film casting, as well as on the use of water-soluble binders (see further references)
• - Adv. Mater. 4 (1992), 73-81 detailed information on the individual slip components and on the use of water-soluble binders

The following examples and comparative examples serve for explanation the invention, without this being intended to impose a restriction. there the polyvinyl alcohols used are those of the company Kuraray Specialties Europe GmbH (KSE) used nomenclature. The number in the first position in the type designation indicates the viscosity of the 4% aqueous solution at 20 ° C as a relative measure of the degree of polymerization polyvinyl alcohol; the second number indicates the degree of hydrolysis (degree of saponification) of the polyvinyl acetate on which the type is based (partially hydrolyzed and fully hydrolyzed types of polyvinyl alcohol). The rules of the usual Kuraray Specialties Europe GmbH Fluctuations regarding the characteristics, d. that is, the viscosity can fluctuate by ± 0.5 mPa s, the degree of hydrolysis has a fluctuation of ± 1 mol%.

A ) Synthesis of the polymer polymer I

100 kg of polyvinyl alcohol Mowiol ^® 4-97 are dissolved in 400 kg of water. To do this, the solution is heated to 95 ° C. for at least 30 minutes. After stirring for 30 minutes, 10.96 kg of n-butyraldehyde are added. The reaction is started at 20 ° C. by metering in 20% strength by weight hydrochloric acid solution (5.61). After the hydrochloric acid metering has ended, the reaction solution is stirred for a period of 2 hours. It is made alkaline with 10% by weight sodium hydroxide solution; pH 8 (25.1 L). The Höppler viscosity according to DIN 53015 is 4.29 mPa s for a 4% by weight aqueous solution and 16.95 mPa s for an 8% by weight aqueous solution. The cloud point at 4% by weight aqueous solution is at ῀32 ° C, at 8% by weight aqueous solution at ῀33 ° C. The precipitation point at 4% by weight aqueous solution is at ῀34 ° C, at 8% by weight aqueous solution at 35 35 ° C.

Polymer II

100 kg of polyvinyl alcohol Mowiol ^® 4-88 are dissolved in 567 kg of water. To do this, the solution is heated to 95 ° C. for at least 30 minutes. After stirring for 30 minutes, 3.14 kg of n-butyraldehyde are added. The reaction is started at 20 ° C. (5.6 l) by metering in 20% strength by weight hydrochloric acid solution. After the hydrochloric acid metering has ended, the reaction solution is stirred for a period of 2 hours. It is made alkaline with 10% by weight sodium hydroxide solution; pH 8 (25.1 L). The Höppler viscosity according to DIN 53015 is 3.89 mPa s for a 4% by weight aqueous solution and 13.33 mPa s for an 8% by weight aqueous solution. The cloud point at 4% by weight aqueous solution is at ῀68 ° C, at 8% by weight aqueous solution at ῀79 ° C. Precipitation points are not observed.

Polymer III

100 kg of polyvinyl alcohol Mowiol ^® 4-88 are dissolved in 567 kg of water. To do this, the solution is heated to 95 ° C. for at least 30 minutes. At an internal temperature of approx. 50–40 ° C, 5000 g of polyethylene glycol 200 are added. After stirring for 30 minutes, 3.25 kg of n-butyraldehyde are added. The reaction is started at 20 ° C. (5.6 l) by metering in 20% strength by weight hydrochloric acid solution. After the hydrochloric acid metering has ended, the reaction solution is stirred for a period of 2 hours. It is made alkaline with 10% by weight sodium hydroxide solution; pH 8 (25.1 L). The Höppler viscosity according to DIN 53015 is 23.94 mPa s for a 4% by weight aqueous solution and 327.40 mPa s for an 8% by weight aqueous solution. The cloud point at 4% by weight aqueous solution is at ῀70 ° C, at 8% by weight aqueous solution at ῀74 ° C. Precipitation points are not observed.

example 1

263.4 g of polymer I (flow time 20 [s], DIN 53211/4 mm / 23 ° C.) were initially introduced and adjusted to a pH of 8.2 with triethanolamine. 36.3 g of Heliogen Blue D 7099 AQ (pigment from BASF AG) and 0.3 g of Agitan 731 (defoamer; Münzing Chemie GmbH) were then added. The resulting mixture was dispersed in a Lau model DAS 200 disperser, the following settings being selected:
0.5 h dispersion time
Shaking frequency 1 (620 min ^-1 ) 300 g glass beads, diameter 2 mm. After the dispersion, the dispersion was examined for its suitability as a printing ink. The results obtained are summarized in Table 1.

Comparative Example 1

The procedure was as in Example 1, but instead of polymer I the same amount of a 11% aqueous solution from Mowiol 4-97 (Run-out time 20 [s], DIN 53211/4 mm / 23 ° C; Kuraray Specialties Europe GmbH) used, which also with triethanolamine on a pH was adjusted to 8.2.

After the dispersion, the Dispersion also examined for its suitability as a printing ink. The results obtained are also summarized in Table 1.

Table 1: Results

For testing gloss and adhesive strength the printing inks, each previously with 0.6 g Tego Wet KL 245 (substrate network additive from Tego Chemie Service GmbH) with a spiral doctor blade (12 μm wet film) from Erichsen OPP films using a control coater K (speed level 3) applied. The gloss was at an angle of incidence of 60 ° with the Refo 3-D reflectometer from Dr. Long according to DIN 67530 or EN Measured according to ISO 2813. The adhesive strength was after 24 hours Elevation of color determined by tesa film 104 from Beiersdorf over the doctor blade or printed ink surface sticks and presses firmly. After that the Tesa film is peeled off suddenly (see keyword adhesive strength in Erwin Schulz, "Flexographic printing from A to Z ", polygraph Verlag, Frankfurt am Main, 1987. The adhesive strength was assessed with marks rated from 1 to 5, with 1 very good adhesion (there is no printing ink detached from the substrate) and 5 means very poor adhesion (ink peels off completely).

Microscopy Investigation

The dispersions from Example 1 and Comparative Example 1 were applied to a slide and microscoped. 1 shows a comparison of the results obtained. The scale of the figure is 1: 110. One can clearly see the improvement in the dispersing effect by using the binder according to the invention, which is shown in the figure as a more fine-grained structure.

Example 2

261 g of polymer II are mixed with 2.4 g of Disperbyk 190 (dispersant from BYK Chemie GmbH), 1.5 g of Byk 019 (defoamer from BYK Chemie GmbH) and adjusted to a pH of 8.2 with triethanolamine. Then 35.1 g of Heliogen Blue D 7086 (pigment from BASF AG) are added and the resulting mixture is dispersed in a disperser from Lau, model DAS 200, the following settings being selected:
0.5 h dispersion time
Shaking frequency 1 (620 min ^–1 )
300 g glass beads, diameter 2 mm

After the dispersion, the Dispersion examined for its suitability as a printing ink. The results obtained are summarized in Table 2.

Example 3

The procedure was as in Example 2, but instead of polymer II, the same amount of polymer III used, which also with triethanolamine to a pH of 8.2 was set.

After the dispersion, the Dispersion also examined for its suitability as a printing ink. The results obtained are also summarized in Table 2.

Comparative Example 2

The procedure was as in Example 2, but instead of polymer II, the same amount of a 13.5% aqueous solution from Mowiol 4-97 (Run-out time 24 [s], DIN 53211/4 mm / 23 ° C; Kuraray Specialties Europe GmbH) used, which also with triethanolamine on a pH was adjusted to 8.2.

After the dispersion, the Dispersion also examined for its suitability as a printing ink. The results obtained are also summarized in Table 2.

Comparative Example 3

The procedure was as in Example 2, but instead of polymer III the same amount of a 13.5% aqueous solution from Mowiol 4-88 (Run-out time 23 [s], DIN 53211/4 mm / 23 ° C; Kuraray Specialties Europe GmbH) used, which also with triethanolamine on a pH was adjusted to 8.2.

After the dispersion, the Dispersion also examined for its suitability as a printing ink. The results obtained are also summarized in Table 2.

Table 2: Results

For testing gloss and adhesive strength the printing inks, each previously with 0.6 g Tego Wet KL 245 (substrate network additive from Tego Chemie Service GmbH) with a spiral doctor blade (12 μm wet film) from Erichsen OPP films using a control coater K (speed level 3) applied. The gloss was at an angle of incidence of 60 ° with the Refo 3-D reflectometer from Dr. Long according to DIN 67530 or EN Measured according to ISO 2813.

Claims (16)

Use of at least one polyvinyl acetal as a binder for aqueous dispersions, the polyvinyl acetal being obtained by reacting at least one polymer (A) which a.) Contains from 1.0 to 99.9% by weight of structural units of the formula (1)

wherein R ^{1 is} hydrogen or methyl, b) 0 to 99.0% by weight of structural units of the formula (2)

wherein R ^{2 represents} hydrogen or an alkyl radical having 1 to 6 carbon atoms, c.) 0 to 70.0% by weight of structural units of the formula (3)

wherein R ³ , R ⁴ , R ⁵ and R ⁶ , each independently of one another, have residues with a molecular weight in the range from 1 to 500 g / mol, each based on the total weight of the polymer (A), with at least one compound (C) of formula (5) is available

wherein R ⁹ and R ^{10 are} each independently hydrogen, COOH, an alkyl group with 1 to 10 carbon atoms or an optionally substituted aryl group with 6 to 12 carbon atoms, characterized in that the polyvinyl acetal based on the total number of structural units of the formula (1) Polymer (A) contains between 65 and 99 mol% of structural units of the formula (1). Use according to claim 1, characterized in that uses a polymer (A) which is based on the total number Structural units of the formula (1) and (2) 0.1 to 40 mol% of structural units of Contains formula (2). Use according to claim 1 or 2, characterized in that a polymer (A) is used which contains 0.01 to 70% by weight of structural units of formula (3) contains which are derived from olefins having 2 to 18 carbon atoms, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic, Derive (meth) acrylamides and / or ethylene sulfonic acid. Use according to claim 3, characterized in that uses a polymer (A) which has structural units of the formula (3) contains which are derived from ethylene. Use according to at least one of the preceding claims, characterized characterized that formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, 2-ethoxybutyraldehyde, capronaldehyde, 2-ethylhexanal, pelargonaldehyde, 3,5,5-trimethylhexanal, 2-formylbenzenesulfonic acid, acetone, Ethyl methyl ketone, butyl ethyl ketone and / or ethyl hexyl ketone as a compound (C) begins. Use according to at least one of the preceding claims, characterized in that the reaction is carried out in the presence of at least one hydroxy compound (B) of the formula (4),

wherein R ⁷ each independently represents hydrogen or an alkyl radical with 1 to 6 carbon atoms, R ^{8 represents} hydrogen or an alkyl radical with 1 to 10 carbon atoms and n is a number greater than or equal to 2, wherein 50.0 to 99.99 parts by weight of polymer ( A) and 0.01 to 50.0 parts by weight of hydroxy compound (B) (total = 100 parts by weight) and per mol of hydroxyl groups which contain the polymer (A) and the hydroxy compound (B) in total, 0.0005 to 0.5 mol of compound (C). Use according to claim 6, characterized in that one uses a hydroxy compound (B) in which n is a number in Range is 2 and 1000. Use according to claim 6 or 7, characterized in that one uses a hydroxy compound (B) in which R ^{8 is} hydrogen. Use according to at least one of claims 6 to 8, characterized in that that one uses a hydroxy compound (B), in which R 'in each case independently of one another Is hydrogen or methyl. Use according to at least one of claims 6 to 9, characterized in that that compounds (B) and (C) are compounded in a molar ratio (C) / Compound (B) greater than or equal to one starts. Use according to at least one of the preceding claims, characterized characterized in that the reaction in the presence of acidic catalysts performs. Use according to at least one of the preceding claims, characterized characterized that the watery Dispersion based on their total weight more than 10 wt .-%, expediently more than 20% by weight, in particular more than 30% by weight, at least of a solvent contains which is based on the total amount of solvent to at least 10 % By weight, expediently at least 20% by weight, in particular at least 30% by weight, of water is. Use according to at least one of the preceding claims, characterized characterized that the watery Dispersion contains at least one other binder. Use according to at least one of the preceding claims, characterized characterized that the watery Dispersion is used to produce a printing ink. Use according to at least one of the preceding claims, characterized characterized that the watery Dispersion used to produce an anti-corrosion agent becomes. Use according to at least one of the preceding claims, characterized characterized that the watery Dispersion used to produce a slip formulation becomes.