DE19917235A1 - Anionic polymer dispersion for use as binder in paint or rendering for external walls has anionic groups neutralized with volatile base and also contains a protonated, non-volatile amine with at least two amino groups - Google Patents

Abstract

Aqueous, anionic polymer dispersions in which the anionic groups are neutralized with a volatile base and the dispersion contains a non-volatile amino compound with at least 2 amino groups, at least 40% of which are protonated, are used as binders for paints and renderings on substrates exposed to weathering. An Independent claim is also included for a process for applying paints or renderings containing these binders to substrates exposed to weathering.

Description

The invention relates to the use of anionically stabilized polymer dispersions as binders for paints or plasters on substrates that are exposed to the weather (briefly outside paints and plasters).

Weather influences must be taken into account when painting and cleaning outside respect, think highly of. The onset of rain shortly after application of the An streaks or plaster will wash out the paint. Ge Therefore, binders are desired that H. already Give waterproof coatings after drying.

Such a binder is known from EP-A-409459. The early one Water resistance becomes anio by adding a polyamine nically stabilized polymer dispersion achieved.

The polymer dispersion contains a volatile base, e.g. B. ammonia, in such amounts that the anionic groups of the polymer are new are tralized and the polyamine is non-ionic. Poly amines, some of which are basic compounds in water protonated form, are added according to EP 409459 deprotonated by ammonia.

This process requires the addition of large amounts of ammonia, what in later processing to impair work leads space and is therefore undesirable.

The use of alkylene polyamines, e.g. B. ethylene polyamines (also Is called polyethyleneimine) in binders for coatings known from JP 51-59928, DE-A-31 21 769 and WO 96/22338.

The object of the present invention were binders which are used in Au exterior painting leads to early water resistance.

Accordingly, the use of aqueous, anionic polymer dispersions as binders for paints and plasters on substrates characterized by the weather net that the anionic groups with a volatile base new tralized and the polymer dispersion is a non-volatile Contains amino compound with at least two amino groups, the Amino groups are at least 40% protonated.  

The polymer dispersed in the aqueous dispersion is generally mean a polymer, which by radical polymerization of ethylenically unsaturated compounds (monomers) is obtained.

The polymer preferably consists of at least 40% by weight, particularly preferably at least 60% by weight, of C ₁ -C ₁₆ alkyl (meth) acrylates, vinyl aromatics with up to 20 C atoms, vinyl esters of carboxylic acids with up to 10 C atoms, olefins or diolefins with up to 10 C atoms or mixtures of these monomers (hereinafter referred to collectively as main monomers).

Preferred (meth) acrylates are C ₁ -C ₈ alkyl (meth) acrylates, in particular methyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate.

Preferred vinyl aromatics are styrene and α-methylstyrene.

Preferred vinyl esters are vinyl acetate and vinyl propionate.

Preferred olefins or diolefins are ethylene, butadiene or Isoprene.

The polymer preferably consists of more than 60% by weight (Meth) acrylates, vinyl aromatics or their mixtures.

In addition to the main monomers, the polymer can contain so-called auxiliary monomers, which are ethylenically unsaturated compounds with functional groups. May be mentioned for. B. Hy droxy compounds, e.g. B. C ₁ -C ₈ hydroxyalkyl (acrylate), amides or nitriles, e.g. B. (meth) arylamide or (meth) acrylonitrile and in particular acids, for. As acrylic acid, methacrylic acid, itaconic acid, Ma linseic acid or fumaric acid. Crosslinking monomers with several ethylenically unsaturated groups can also be used.

A preferred auxiliary monomer are those with a carbonyl group e.g. B. an aldehyde or keto group.

Called at z. B. Diacetone acrylamide.

The polymer contains an auxiliary monomer containing carbonyl groups preferably in amounts of 0.01 to 30 wt .-%, especially before added from 0.05 to 10 wt .-%, based on the polymer.  

The carbonyl group can be dried later with dihydrazi crosslink the, especially carboxylic acid dihydrazides. Called be z. B. dicarboxylic acid dihydrazides, especially carboxylic acid di Crosslink hydrazides.

May be mentioned for. B. dicarboxylic acid dihydrazides, especially adipine acid dihydrazide.

Accordingly, the polymer dispersion preferably contains such term dihydrazides for later crosslinking with carbonyl groups, if auxiliary monomers containing carbonyl groups are present in the polymer are.

The glass transition temperature (T _g ) of the polymer is preferably above -20 ° C, in particular above 0 ° C. Values of 120 ° C are generally not exceeded. The T _g is preferably between -20 and 60 ° C, particularly preferably between 0 and 60 ° C.

The T _{g of} the polymer can be determined using the DSC method (differential scanning colorimeter) in accordance with ASTM 3418/82.

Aqueous dispersions of the polymer can be prepared by preparing the Polymers by emulsion polymerization or z. B. by Disper yaw one by solution or bulk polymerization provided polymers can be obtained in water.

The dispersion stability of the polymer particles is the Emul sion polymerization z. B. by the emulsifiers used or Protective colloids guaranteed.

The emulsifiers or protective colloids can be anionic groups contain which to stabilize the polymer particles in the Contribute to dispersion.

The polymers themselves can also contain anionic groups, which bring about dispersion stability or at least add to it contribute.

Acid groups can be used in polymers e.g. B. by using ethylenically unsaturated acids, especially carboxylic acids, e.g. B. Acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, be included in the polymerization.

In a preferred embodiment, the polymer contains min at least 0.5 wt .-%, based on the polymer, ethylenically un saturated acids, especially carboxylic acids.  

The total amount of anionic groups is preferably (i.e. in the emulsifier, protective colloid and / or polymer) 0.001 to 1, particularly preferably 0.01 to 0.1 and very particularly preferably 0.02 to 0.05 mol per 100 g of polymer.

Preferably at least 50% is particularly preferred at least 80%, very particularly preferably 100% of all anionic groups neutralized with a volatile base.

A volatile base is a base with a boiling point below 100 ° C at 1 bar.

Ammonia, monoethylamine, diethylamine, triethylamine, Monomethylamine, dimethylamine and trimethylamine. Is preferred Ammonia.

A conversion of the acid groups into anionic groups can, for. B. simply by adding the volatile base to the aqueous dispersion respectively.

The volatile base can, of course, based on the acid groups can also be used in excess. However, it is not necessary even more helpful than equimolar amounts of volatile Base, based on the acid groups.

In particular, a depro is within the scope of the present invention toning of the following non-volatile amino compound we the desired still required, so for this reason too dispenses with a corresponding excess of the volatile base and so the stated degree of protonation of the non-volatile amino connection is guaranteed.

Amino compounds with a boiling point above 100 ° C., preferably above 1 bar, are considered to be non-volatile. The weight average molecular weight M _{W of} the non-volatile amino compound is preferably 500 to 5000 g / mol, particularly preferably 500 to 1500 g / mol.

The number average molecular weight M _n is also preferably 500 to 5000, particularly preferably 500 to 1500 (determined by gel permeation chromatography, polyethylene oxide standard).

M _W is determined by measuring the light scatter. The amino compound can contain primary, secondary and / or tertiary amino groups.

Preferred non-volatile amino compounds are alkylene polyamines, preferably C ₂ -C ₄ alkylene polyamines.

Modified alkylene polyamines, i.e. H. Derivatives of alkylene polyamines. Preferably also exist Derivatives of at least 50% by weight, in particular at least 80% by weight of alkylene amine groups. May be mentioned in particular alkoxylated, e.g. B. propoxylated alkylene polyamines.

Ethylene polyamines, also called polyethyleneimines, are particularly preferred. they consist of

Units.

In addition to secondary N atoms of the grouping - (CH ₂ -CH ₂ -NH-), the polyethyleneimines also contain tertiary N atoms in

or terminal primary N atoms - ((CH ₂ -CH ₂ NH ₂ ).

Polyethyleneimines are e.g. B. under the brand name Lupasol® or Polymin® available from BASF. The base strength, expressed in pKb units, the non-volatile amine compound is before preferably 7 to 11, particularly preferably 10 to 11.

The base strength, pKb is preferably larger, in particular mind at least 0.25 than that of the volatile base.

The non-volatile amino compound is in the aqueous polymer dispersion preferably in amounts of 0.1 to 25 parts by weight, be preferably 2 to 20 parts by weight, particularly preferably 3 to 10 parts by weight Parts based on 100 parts by weight of the polymer present.

The non-volatile amino compound can be added to the at any time aqueous polymer dispersion, also long before the later use tion, because the storage stability of the polymer disper sion is not affected.  

The aqueous polymer dispersion is used as a binder for paints or plasters on substrates that are exposed to the weather, (short exterior paints or plasters). Preferred substrates are exterior walls of buildings.

The exterior paints or plasters can be white in addition to the binder tere additives, e.g. B. pigments, fillers, dispersants tel, defoamers, thickeners, leveling agents. The Additives can be added to the polymer dispersion and in be be mixed in a known manner.

The polymer dispersions or the paints and plasters are stored stable. There is little or no coagulum to be observed.

The paints and plasters, which ent the above polymer dispersion ent hold, develop quickly after application to the substrates an early water resistance, so there is a risk of washing out no longer exists or is at least reduced by rain.

The coatings obtained have a high water resistance ness, show hardly any bubbles and show no whitening. Except the coatings show less yellowing, ins especially when using the alkoxylated alkylene polyamines.

Examples clean A) non-volatile amino compound

An ethylene polyamine with a weight-average molecular weight M _W of 800 g / mol was used as the non-volatile amino compound.

B) polymer dispersion

An acrylic ester-styrene copolymer was used as the polymer dispersion used. The acid groups are exactly equimolar Amount of ammonia neutralized.

Manufacturing and testing

Plasters with the following composition were produced:  

Dispersion of an acrylic ester-styrene-acrylic acid copolymer (50%) in water 202 parts by weight Sodium polyphosphate, 25% solution 8 parts by weight MHEC 10,000, 3% solution 32 parts by weight Preservative 3 parts by weight Defoamers, e.g. B. Agitan 280 4 parts by weight White spirit (180-210 ° C) 10 parts by weight Butyl diglycol 10 parts by weight Basophob WDS 6 parts by weight Titanium dioxide rutile, e.g. B. Kronos 2043 70 parts by weight Omyacarb 40 GU 165 parts by weight Omyacarb 130 GU 160 parts by weight Calcilit 0.5-1.0 KA (...) 320 parts by weight water 10 parts by weight           1000 parts by weight         

In the embodiment according to the invention, the plaster was 3 parts by weight (50% in water) ethylene polyamine, based on 100 parts by weight Acrylic ester-styrene copolymer added. The nitrogen atoms of the ethylene polyamine were 40% by weight in the composition cationic form. The pH was 11.

The composition was stable on storage. The formation of coagulum could not be observed.

For comparison, the polymer dispersion was also added without the Ethylene polyamine tested.

To test the water resistance, a circular plaster pattern (diameter 5 cm, thickness 0.5 cm) was drawn onto a mineral fiber board. The distance between the sample and the glass edge was approx. 5 cm. The cleaning pattern was flashed off at 23 ° C, 50% relative humidity. The mineral fiber plate was then placed in a beaker filled with water so that the cleaning pattern was completely wetted by water. As a measure of the water resistance, the time until the start of dispersion from the plaster pattern was measured. The beginning of the outflow is clearly recognizable by the milky-white color of the water. The later the flow begins, the higher the water resistance of the cleaning pattern.

More examples of paintings

Production examples of aqueous resin dispersion mixtures and An Application examples of aqueous coating compositions and comparative examples in which these are used are shown in fol described above. In the examples below are the "Parts" or "percentages", unless expressly stated otherwise stated, always "parts by weight or" weight percent ".

Production Example 1 of an aqueous resin dispersion mixture

Mixture 1 was prepared by mixing 40 parts of what water, 50 parts styrene, 45 parts butyl acrylate, 3 parts acrylic acid and 2 parts of methyl acrylamide with 4 parts of a 35% aqueous solution of a sulfated, esterified sodium salt of Addition product from 20 mol ethylene oxide and p-nonylphenol (after hereinafter referred to as "anionic emulsifier A") and intense Stir until an even emulsion is formed.

Then 40 parts of water and 4 parts of the above anio African emulsifier A in one with temperature controller, anchor stirrer, Inlet vessel, thermometer and nitrogen inlet pipe equipped submitted reaction vessel and the internal temperature of the reak tion vessel increased to 90 ° C.

By mixing 0.5 parts of potassium peroxodisulfate with 16 parts An aqueous solution was prepared separately from water and this referred to as mixture 2 and the above mixture 1 then at constant inside the reaction vessel held at 90 ° C dropwise over 3 hours in the Vessel introduced.

After the dropwise feeding was stopped, the reaction gene continue heating at the same temperature for 1 hour and then by adding 2.5 parts of 28% aqueous ammo niak neutralized. After cooling the reaction mixture 8 parts of Lupasol FC (polyethyleneimine, Solids content: 50%, Mw = 800, manufacturer: BASF) as alkylene po Lyamine derivative added to the aqueous resin dispersion to get mixture 1.  

Production Examples 2 to 7 for aqueous resin dispersion mixture gene

Aqueous resin dispersion mixtures were made according to the above obtained manufacturing example 1, where in the monomer mixtures and the like as shown in Table 1 were put, varied.

Application example 1

An aqueous coating agent was prepared using the in The above-mentioned Production Example 1 aqueous resin dis Persian mix made.

Specifically, 20 parts of water, 1 part of aqueous 10% sodium umpolyphosphate solution, 0.1 part of 28% aqueous ammonia and 60 Parts titanium oxide (Taipake R930, manufacturer: Ishihara Sangyo (KK)) mixed and thoroughly dispersed into a pigment paste. Then 100 parts of the in the corresponding manufacturing game 1 obtained resin dispersion mixture, 7 parts Texanol (Her Steller: Eastman Kodak) (as an aid for film formation), 0.3 parts of 28% aqueous ammonia and 0.2 parts of binder (SN731, manufacturer: Sannopko (KK)) mixed and violently with the pigment paste mentioned above to an aqueous coating agent stirred in the form of an aqueous paint.

The evaluation results for this aqueous coating agent are shown in Table 3.

Application examples 2 to 6 and comparative examples 1 to 3

Various aqueous coating agents were used as in the application Example 1 using the pigment paste obtained there and the other ingredients listed in Table 2 poses.

There were evaluations; their results in Tables 3 and 4 are shown.

Evaluation methods (a) Shelf life

Each aqueous coating agent was stored at 50 ° C and the Viscosity using a stomer viscometer in each case according to ei measured storage periods of 7 days or 28 days, and the change in viscosity was determined.  

(b) drying properties

Each aqueous coating agent was applied to glass plates in a Applied a layer thickness of 150 µm; the plates were at 20 ° C and 65% relative humidity under draft-free conditions dried for 3.8 or 20 minutes and then immediately immersed in water for 5 minutes.

The glass plates were removed from the water and the condition of the color layer remaining on the glass surface was assessed by eye as follows:
○: The paint layer was not washed off.
∆: The paint layer was partially washed off.
x: The paint layer was almost completely washed off.

(c) Water resistance

Each aqueous coating agent was brushed off applied as a layer of 100 g / m on slate slabs; the Plates were kept at 20 ° C and 65% relative humidity dried for 5 days. They were then in for 5 days Submerged in water and then blistered in with the naked eye the layer of paint examined.

The results are shown in Tables 3 and 4. In the column Water resistance of these tables indicates "VS" blistering in the color layer, the number given with the extent the blistering increases. Furthermore, "0" indicates that none Irregularities were seen on the paint layer.

As shown in these tables, all aqueous Be layering agent in the application examples 1 to 6, in which aqueous resin dispersion mixtures of the present invention ver were applied, all in terms of shelf life, fast drying and water resistance excellent properties on.

It should be noted that in each of the tables the following letters ways are used:

Monomer

St: styrene
BA: butyl acrylate
AA: acrylic acid
MA.AM: methacrylamide
MMA: methyl methacrylate
2EHA: 2-ethylhexyl acrylate
DAAM: diacetone acrylamide
MAA: methacrylic acid
IA: itaconic acid
t-BMA: t-butyl methacrylate

Cationic emulsifier A 30% aqueous trimethylammonium lauryl chloride solution

KPS: potassium peroxodisulfate
V50: 2,2'-azobis (2-amidinopropane) hydrochloride
Lupasol HF Mw = 25,000, solids content: 56%, manufacturer: BASF
Lupasol P Mw = 750,000, solids content: 50%, manufacturer: BASF
(*) Emulsifier () + (): The former is the one that is placed in the reaction vessel, the latter is the one that is added to mixture 1.

The present invention provides fast drying aqueous coating compositions with greatly improved drying properties, high water resistance during the initial phase of drying - especially at low temperatures and high air humidity - as well as good storage stability and also provides the aqueous resin dispersion compositions used therefor.

Further examples A to D (with carbonyl-containing poly meren) Manufacturing

40 parts by weight of deionized water and 4 parts by weight of one Emulsifier solution (a) was placed in a reaction vessel.

The following feeds were metered in within 2 hours:
(Emulsifier solution: Na polyethylene glycol (EO = 25) nonylphenolsul fat, 25% by weight in water

Inlet I

2EHA 34 parts by weight MMA 50 parts by weight St 10 parts by weight AA 2 parts by weight water 40 parts by weight Emulsifier solution (a) 4 parts by weight t-dodecyl mercaptan 0.1 parts by weight

Inlet II

water 16 parts by weight Potassium persulfate 0.5 parts by weight

After the feeds had ended, the product was still at 1 hour Kept at 90 ° C. 2.5 parts by weight of ammonia were added and the mixture was cooled.

Then 8 parts by weight of alkylene polyamine (Lupasol FC) were added.

formulation

A pigment paste was made from

deionized water 20 parts by weight 10% napolyphosphate solution 1 part by weight 28% ammonia solution 0.1 parts by weight Titanium dioxide 60 parts by weight

The paint was made by mixing 100 Parts by weight of the polymer dispersion (A-D) with the pigment paste below Add 7 parts by weight of Texanol, 0.3 parts by weight of 28% ammonia solution and 0.2 parts by weight of thickener.

Test methods Water resistance

The water resistance was determined as described above.

evaluation

Numbers 1 to 9: fewer blisters as the number increases
VS: Blister very small
S: small blister
LM: Blister medium
L: big

Whitening

The paints were applied with 180 μm film thickness (wet) to polyacrylic lat plates, dried for 5 days at 20 ° C. and 65% relative air humidity and then treated with water at 20 ° C. and 400 ° C. for one or 2 days. The whitening was determined with a color tester as the color difference (Δ ^L value):

The results are shown in Table 5.

Examples E

Use of a modified alkylene polyamine.

The results are summarized in Table 6.

The coatings show a significantly lower yellowing.

Claims (13)

1. Use of aqueous, anionic polymer dispersions as binders for paints and plasters on substrates which are exposed to the weather, characterized in that the anionic groups are neutralized with a volatile base and the polymer dispersion contains a non-volatile amino compound with at least two amino groups, whose amino groups are at least 40% protonated. 2. Use according to claim 1, characterized in that the weight average molecular weight M _{W of} the amino compound is 500 to 1500 g per mol. 3. Use according to one of claims 1 or 2, characterized ge indicates that the amino compound is an Al kylenpolyamin, in particular an ethylene polyamine. 4. Use according to any one of claims 1 to 3, characterized records that the pKb value of the amino compound at Normalbe conditions (1 bar, 21 ° C) from 7 to 10. 5. Use according to one of claims 1 to 4, characterized records that the polymer dispersion 0.1 to 10 parts by weight of the Contains amino compound based on 100 parts by weight of polymer. 6. Use according to any one of claims 1 to 5, characterized records that the amount of anionic groups 0.001 to Is 1 mole per 100 g of polymer. 7. Use according to one of claims 1 to 6, characterized records that the volatile base is ammonia acts. 8. Use according to one of claims 1 to 7, characterized records that the polymer at least 0.5 wt .-% of a ethylenically unsaturated acid, especially a carbon contains acid. 9. Use according to one of claims 1 to 8, characterized records that the polymer from 0.01 to 30 wt .-% from a ethylenically unsaturated compound with a carbonyl group exists as a structural component.   10. Use according to one of claims 1 to 9 characterized thereby records that it is the non-volatile amino bond is alkoxylated alkylene polyamines. 11. Process for applying paints and plasters to sub strate, which are exposed to the weather, thereby identified records that the paints or plasters as a binder contain aqueous, anionically stabilized polymer dispersion, their anionic groups with a volatile base neutrali are based and the polymer dispersion with an amino compound contains at least two amino groups, the amino groups of at least 40% are protonated. 12. The method according to claim 11, characterized in that the Paint or plaster are applied and then ge be dried, whereby the volatile base escapes. 13. The method according to any one of claims 11 or 12, characterized ge indicates that the paints or plasters on building exterior walls are applied.