JPS5845962B2 - How to get the best results - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The problem of wet adhesion of dispersion coatings on smooth, non-absorbent substrates has long limited the use of certain dispersion coatings.

Dispersion coatings with low pigment content that dry to form a glossy or slightly dull film on the substrate have poor adhesion to smooth, non-absorbent substrates when rewetted after drying.

Wet adhesion is particularly poor when using new paint that has not yet aged.

If a washable paint coating is desired, a dispersion paint with a low pigment content is chosen.

By increasing the binder content of such coatings, tight and washable films are obtained.

Dispersed coatings that dry to a glossy or slightly dull film are likewise less than 40%, generally from about 10 to
It has a pigment concentration of 25%.

In addition, the dispersion coating may be used in large amounts - from about 3 to
%- of organic solvents.

The gloss, flow and opening time are influenced, for example, by water-miscible polyhydric alcohols having up to 6 C atoms, in particular ethylene and propylene glycols or their monomethyl or monobutyl ethers.

To improve the film strengthening, limited water-soluble solvents are used, such as monoglycol ethers of carboxylic acids and especially esters of carboxylic acids with monoalkyl ethers of glycols or oligo-glycols.

Butyl diglycol-acetate is the most widely used representative of this group.

The combination of low pigment content and high solvent content has a decisive negative effect on the wet adhesion of the dispersion paint coating.

Paints with poor wet adhesion will exhibit poor wet adhesion properties when applied to smooth, non-absorbent substrates, such as old alkyd or oil-based paint coatings, even if they are made to be self-cleanable. no longer have it.

In damp interiors, such as kitchens, bathrooms, or in many industrial rooms where the formation of condensate water must be expected, new coatings may be removed from the substrate if adequate wet adhesion is not provided. Can be peeled off.

Furthermore, poor wet adhesion complicates the painting process.

For example, when applying foundations and the upper half of walls or walls and roofs in different colors, the first coating can be smeared with different paints by brush slips.

Immediately, dirt can be wiped off with a damp cloth.

However, if the wet adhesion is poor, the original paint may be damaged or removed together.

For these reasons, attempts have been made to modify synthetic resin dispersions in such a way that the dispersion coatings produced therewith exhibit the desired wet-adhesion properties.

In particular, according to German Patent Application No. 1,595,501, in the preparation of synthetic resin dispersions by polymerizing suitable monomers in the form of an aqueous emulsion, from 0.2 to 15% by weight of oxirane, based on the total weight of the monomers, is used. It is known to incorporate group-containing compounds as comonomers into polymers and then to act on the copolymers with ammonia or amines at room temperature.

Suitable oxirane compounds are in particular glycidyl esters of acrylic or methacrylic acid, and also allyl glycidyl ether or vinyl glycidyl ether.

Dispersion paints made with synthetic resin dispersions of this type already have really good wet adhesion properties.

However, its wet adhesion is not at all sufficient for many practical applications.

Synthetic resin dispersions having halogen-containing monomers in the polymer and which are generally rendered alkaline with ammonia after cooling are also already known.

However, it has not been investigated whether a dispersion paint produced using this material exhibits wet adhesion.

Wet adhesion cannot be achieved by adjusting to normal alkalinity in the cooled state.

The present inventor has determined that 0.5 to 10% by weight based on the total monomer amount
A synthetic resin dispersion obtained by copolymerizing a nucleophilically substituted α-β-unsaturated halogen compound of 2 equivalents of ammonia or more per equivalent of halogen that can be substituted with p
It has been found that a synthetic resin dispersion can be obtained which imparts extremely good wet adhesion to the dispersion paint made from the synthetic resin dispersion by treating with ammonia to the extent that it exhibits an H-value. Ta.

Ammonia can be added to the finished dispersion in gaseous or liquid or solution form.

It is particularly preferable to add it in the form of a concentrated or diluted aqueous solution.

Ammonia can be added to the dispersion during the post-reaction period, ie between the end of the polymerization and just before cooling.

However, it is particularly expedient to add the ammonia as an aqueous solution immediately after the end of the polymerization and at least 30 minutes to 1 hour before cooling of the reaction mixture.

If there are special reasons, it is also possible to add ammonia to the cooled dispersion and then warm it above 50° C. for 30 minutes to 1 hour.

If the copolymer contains free carboxyl groups, the dispersion should not be aged more than one day in this case.

Preferably, the addition of ammonia is carried out at a temperature of 50-95°C.

It is expedient to choose the temperature at which the polymerization takes place.

If ammonia is added at very high temperatures, such as 95°C or higher, significant amounts of gas and bubbles can be formed.

This can be avoided by operating under pressure and optionally by adding defoamers.

The reaction according to the invention of halogen compounds and ammonia at elevated temperatures already provides comparable wet adhesion properties even with a lower proportion of halogen compounds in the copolymer than if the reaction were carried out at room temperature. .

The dispersions produced according to the invention can furthermore be processed immediately after production into coatings with high wet adhesion;
On the other hand, reaction with ammonia in the cooled state requires long intermediate storage, which naturally slows down production.

The amount of ammonia to be used is determined such that 2 moles of ammonia are used per equivalent of halogen in the copolymer.

If the copolymer has free carboxyl groups, a corresponding additional amount of ammonia is required to neutralize them.

The result of the ammonia addition should be a pH value of above 8, in particular above 9, measured using a glass electrode in the thermal dispersion.

Instead of ammonia, which can be used in gaseous or especially aqueous solution form, it is also possible to use compounds which separate ammonia at temperatures above 50 DEG C., especially urotropin.

In this case, it is necessary to use at least 1 mole of urotropin per equivalent amount of halogen.

Dispersions which are unstable at pH values of approximately 6.5 which can be achieved with urotropin, especially dispersions of acrylate homopolymers, must additionally be made alkaline with ammonia.

The amount of halogen compound can vary in the range from 0.5 to 10% by weight, based on the total amount of monomers used.

At amounts less than 0.5%, the wet adhesion properties are significantly reduced, and at amounts greater than 10%, no substantial improvement can be obtained any longer.

Generally 1 to 3% by weight of halogen compound is sufficient.

However, if this dispersion is to be mixed with a halogen compound-free dispersion, an amount of more than 10% of halogen compound can be used.

When producing the dispersion according to the invention, at least 40%
and when up to 80% of other monomers are polymerized,
It has been found to be expedient to add the halogen compound to the polymerization mixture for the first time.

This results in synthetic resin dispersions with higher wet adhesion properties with lower amounts of halogen compounds than if the halogen compounds were added continuously during the polymerization together with the other monomers.

In this way up to 60% of the nitrogen compounds can be saved.

Halogen compounds which can be used for the dispersions prepared according to the invention include α-β-unsaturated compounds containing at least one nucleophilically substituted halogen, in particular chlorine or bromine. , for example chloro- or bromo-1 deoxyacid-vinyl ester, β-chloroethyl-vinyl ether, β-chloroethyl acrylate or monomethacrylate.

There are no restrictions on the selection of other monomers.

All monomers commonly used for producing synthetic resin dispersions are suitable, which can be combined according to actual requirements.

For example, vinyl esters of organic carboxylic acids having 1 to 30, in particular 1 to 20, C atoms in the carbon skeleton, such as vinyl acetate, vinyl propionate, isononanoic acid vinyl ester, etc. up to 20. Vinyl esters of branched monocarboxylic acids with carbon atoms: acrylic or methacrylic esters with 1 to 30, in particular 1 to 20, carbon atoms in the alcohol residue, such as ethyl acrylate, isopropyl acrylate , butyl acrylate, 2-etherhexyl acrylate, methyl methacrylate, butyl methacrylate; aromatic or aliphatic α-β-unsaturated hydrocarbons, such as ethylene, propylene, styrene, vinyltoluene, etc.; vinyl halides, such as vinyl chloride; unsaturated Nitriles, such as acrylonitrile; diesters of maleic or fumaric acids, such as dibutyl-maleinate or dibutyl fumarate; α-β-unsaturated carboxylic acids, such as acrylic acid, methacrylic acid or crotonic acid, and derivatives thereof, such as acrylamide or meth Acryl-amide and the like are suitable.

When selecting suitable monomers or monomer combinations, the generally known conditions for producing coating dispersions must be taken into account.

For example, it should be noted, in particular, that under the intended drying conditions of the paint, the polymers that form the coating are formed;
The selection of monomers for producing the copolymer should then be made depending on the polymerization parameters in such a way that one can expect the formation of a copolymer with a rogen compound according to the invention.

Some suitable monomer combinations are listed below: vinyl acetate/butyl acrylate/chloro-(from)-acetic acid ester, vinyl acetate/butyl acrylate/β-chloroethyl-vinyl ether, vinyl acetate/butyl acrylate/β-chloroethyl- (meth)-acrylate, vinyl acetate/di-
Butyl-maleinate/chloro-(from>-rh acid vinylnistit, vinyl acetate/di-butyl maleinate/β-chloroethyl-vinyl ether, vinyl acetate/di-butyl fumarate/chloro-(
bromo)-vinyl acetate, vinyl acetate/vinyl isononanoate/chloro-(from-) vinyl acetate, vinyl acetate/vinyl isononanoate/β-chloro-ethyl vinyl ether, vinyl acetate/vinyl isononanoate/β- Chloro-ethyl (-meth-)acrylate, vinyl acetate/2-ethylhexanoic acid vinyl ester/chloro-(from-)acetic acid vinyl ester, vinyl acetate/2-ethylhexanoic acid vinyl ester/β-chloroethyl-vinyl ether, vinyl acetate )/vinyl ester of branched carboxylic acids with 10 carbon atoms/vinyl chloro(-bromo-)acetate, vinyl acetate/vinyl ester of branched carboxylic acids with 10 carbon atoms (10-C vinyl acetate/ethylene/chloro(-from-) acetate vinyl ester, vinyl acetate/ethylene/β-chloroethyl vinyl ether, vinyl acetate/ethylene/vinyl chloride/chloro(- 7'Romo-)acetic acid vinyl ester, vinyl acetate/ethylene/vinyl chloride/β-chloro-ether-vinyl ether.

If the dispersion is intended to be used in coatings with high wet adhesion, the emulsifier content should be as low as possible.

However, some amount of emulsifier is often required to produce a sufficiently stable dispersion.

This is especially necessary if small particle sizes are desired or if the polymerization is carried out in the absence of protective colloids.

Furthermore, emulsifiers are often important to achieve good pigment wetting and dispersibility when producing coatings.

On the other hand, excessive emulsifier content can have a decisive negative effect on important properties, such as water resistance.

The dispersion should contain at most 2% ionic emulsifier and at most 4% nonionic emulsifier, based on the polymer content.

Nonionic emulsifiers include, for example, ethoxylation products of alkyl polyglycol ethers, such as lauryl, oleyl or stearyl alcohol, or mixtures such as coconut alcohol; alkylphenol-
Polyglycol ethers such as ethoxylation products of octyl- or nonyl-phenol, diisopropyl-phenol, triisopropylphenol or di- or tri-tert-butyl-phenol; or ethoxylation products of polypropylene oxide are used. It will be done.

First of all, anionic emulsifiers are suitable as ionic emulsifiers.

In this case, mention may be made of the alkali metal or ammonia salts of alkyl, aryl or alkyl aryl sulfonates, -sulfates, -phesphaates, -phosphonates or other compounds having anionic end groups, with carbonization. An oligo- or polyethylene oxide unit may also be present between the hydrogen residue and the anion group.

゛Typical examples include sodium lauryl sulfate, sodium octylphenol glycol ether sulfate, sodium dodenlebenzene sulfonate, and sodium lauryl diglycol.
sulfate, ammonium-tolyl-tert-butylphenol penta- or -octa-glycol-sulfate.

Protective colloids can optionally be natural substances such as gum arabic, starch, alginates or modified natural substances such as methyl-, ethyl-, hydroxyalkyl- or carboxymethyl-cellulose, or polyvinyl-alcohol, polyvinyl-pyrrolidone. Synthetic materials such as or mixtures of these materials may be used.

Particularly advantageously used are modified cellulose derivatives and synthetic protective colloids.

Oil-soluble and/or especially water-soluble radical formers or redox systems are used to initiate and continue the polymerization.

For example, hydrogen peroxide, potassium ammonium peroxydisulfate, dibenzoyl peroxide, lauryl peroxide, ) 'J 7 3rd
-7'' thyl-peroxide, bis-azodi-inbutyronitrile, etc. alone or with reducing components such as sodium beasulfite, Rongalit.
(trade name), crucose, ascobic acid and other reducing compounds.

Example 1 3 of 21 equipped with a stirrer, reflux condenser, addition funnel and thermometer and placed in a heating bath
In a head flask, a dispersion consisting of the following components is heated with stirring, the polymerization being initiated.

650 parts by weight of water, 12 parts by weight of nonylphenol-polyglycol ether containing about 30 ethylene oxide units, 12 parts by weight of copolymer (90 parts by weight of N-vinyl N-methylacetamide and 10 parts by weight) maleic acid diisooctyl ester), 1.5 parts by weight of sodium acetate, 0.9 parts by weight of sodium vinyl sulfonate, 2.5 parts by weight of ammonia, um peroxydisulfate, 48 parts by weight of vinyl acetate and 12 parts by weight of 10-C-acid monovinyl ester.

When the temperature has risen to 70 DEG C., a mixture of 216 parts by weight of vinyl acetate and 54 parts by weight of 10-C acid vinyl ester is started to be metered in.

The dosing time is approximately 90 minutes.

Immediately following this, 216
parts by weight of vinyl acetate, 54 parts by weight of 10-c acid-
A mixture of vinyl ester and 18 parts by weight of vinyl chloroacetate is metered in.

The total dosing time is approximately 3 hours and the polymerization temperature is 70.degree.

After the monomer addition is complete, a solution of 0.5 parts by weight of ammonium-beroxy disulfate in 15 parts by weight of water is added.

Afterheating for 110 minutes under continuous stirring at the polymerization temperature (70° C.), then slowly adding 23 parts by weight of urotropin in 40 parts by weight of water and stirring for a further 10 minutes at 70° C. After that, cool it down.

The pH value is 6.1 and the solids content is approximately 50%.

Example 2 In an apparatus as described in Example 1, a dispersion consisting of the following composition was heated to 70° C.: 618 parts by weight of water, 18 parts by weight of nonylphenol having about 30 ethylene oxide units. Polyglycol ether, 1.5 parts by weight of sodium acetate, 12 parts by weight of hydroxyethyl cellulose (average degree of polymerization: approx. 40
0 (molecular weight approximately 100,000)), 2.5 parts by weight of ammonium peroxydisulfate, 48 parts by weight of vinyl acetate and 12 parts by weight of dibutyl maleinate, and at this temperature for 90 minutes. A mixture consisting of 216 parts by weight of vinyl acetate and 45 parts by weight of dibutyl maleinate was metered in, followed immediately by the addition of 216 parts by weight of vinyl acetate, 54 parts by weight of dibutyl maleinate and 18 parts by weight over a period of 90 minutes. bromo-vinyl acetate ester is metered in.

After feeding, 0.5 parts by weight of ammonium peroxydisulfate in 15 parts by weight of water are processed and heated after 2 hours.

One hour before cooling, the pH value is adjusted to 9.4 with 40 parts by weight of 25% ammonium.

The solids content is approximately 50%. Example 3 In an apparatus as described in Example 1, the following composition was prepared: 625 parts by weight of water, 18 parts by weight of an oleyl-polyglycol ether having about 25 ethylene oxide units, 0.2 parts by weight of sodium mooddecylbenzene-sulfonate, 12 parts by weight of hydroxyethyl-cellulose (average degree of polymerization 400, molecular weight approximately 100,000), 1.5 parts by weight of sodium acetate, 2.5 parts by weight of ammonium peroxydisulfonate. ate, 63 parts by weight of a monomer mixture taken from a mixture consisting of 450 parts by weight of vinyl acetate, 150 parts by weight of isononanoic acid vinyl ester and 30 parts by weight of vinyl chloroacetate ester. The mixture is heated to 70° C. and at this temperature the remaining monomer mixture (567 parts by weight) is metered in over a period of 3 hours.

After dosing, a solution of 0.5 parts by weight of ammonium peroxydisulphate in 15 parts by weight of water is added and afterheating is carried out for 2 hours.

One hour before cooling, the pH value was adjusted to 9.5 with 40 parts by weight of 25% ammonia.

The solids content is approximately 50%. Examples 4-7 Proceed as described in Example 3, except Example 4: Ammonia is added to the dispersion cooled to room temperature (approximately 25° C.).

Example 5: No ammonia is added to the dispersion.

Example 6: Copolymerization is carried out without chloroacetic acid vinyl ester, ammonia is added to the dispersion at 70° C. 1 hour before cooling.

Example 7: Copolymerization without chloroacetic acid vinyl ester and no ammonia added to the dispersion.

To produce a dispersion coating with high wet adhesion according to the invention, the dispersion obtained according to the above examples is mixed with a pigment dispersion.

Pigment dispersions or pigment pastes of this type are suitable for producing dispersion paints with low pigment content and particularly glossy paints and consist, for example, of titanium dioxide homogeneously dispersed in water.

These generally contain protective colloids such as cellulose derivatives, such as hydroxyethyl-cellulose, and dispersants, such as salts of poly-(meth)-acrylic acid or sodium-poly-phosphate.

Typical ingredients of pigment dispersions also include antimicrobial preservatives, defoamers, pH-stabilizers and fillers.

Particularly suitable titanium dioxide pigments include Rutile
) and Anatas.

For glossy paints, it is important that the average particle diameter of the pigment is near the lower limit of the wavelength of light, ie about 0.4 to 0.2 microns.

In order to produce matte paints with low pigment contents, special silicate pigments with a large surface area can be used together, for example.

Matte paints with high binder content result in coatings that are easily cleaned.

The pigment paste may of course also contain chromatic pigments,
However, the desired color tone can be similarly adjusted by coloring a dispersion coating containing a white pigment.

Pigment dispersions can be prepared by known methods, for example by dispersing the pigment in a Dinrover or by dispersing in a ball or sand mill.

In order for the pigment dispersion to be used in gloss paints, the dispersion must not contain significant amounts of pigment aggregates.

This is because the gloss is impaired.

Auxiliary agents, such as softeners, crosslinkers, buffer substances, thickeners, teixotropic agents, rust inhibitors, alkyd resins or drying oils, can be added either to the dispersion or to the finished dispersion coating.

In this case, softeners include compounds that lower the film-forming temperature and remain in the polymer for a long time, such as dibutyl phthalate, rather than the solvents with temporary action mentioned earlier as film-hardening agents.

The use of the synthetic resin dispersion produced according to the invention as a binder in dispersion coatings with low pigment content and dispersions containing the synthetic resin dispersion produced according to the invention are likewise subject matter of the invention. It is.

To test wet adhesion, a glossy paint is prepared according to the following recipe.

(1) Water 41.0 parts by weight 3% aqueous solution of Tylose H2015,6 (trade name) Calgon N (quotient 0.4μ)
Title) (Solid) Dispersant PA30 Ammonia (25%) Preservative Defoamer Titanium dioxide 175.0 // (Particle size: 0.2~0.4μ) ■・2-Propylene glycol 10.0 weight (2) 710.0 parts by weight of the dispersion (solids content 50%), which is 25% of the 2.0 parts by weight if the pH-value is not above about 7; (mixed with ammonia).

Then, while stirring, gradually (3) Butyl-diglycol acetate 10.0 parts by weight 1,2-propylene glyco-27.0 parts by weight Add a mixture consisting of:

The liquid or soluble components listed in (1) except 1,2-propylene glycol are placed in advance in the order listed in a stirring vessel, and the pigment is dispersed therein using a dissolver.

Next, add 2-2 propylene glycol.

This pigment paste is produced in large quantities in order to ensure the same conditions for mixing with the various dispersions to be tested, for example the same conditions for the dispersion of the pigment.

To produce the individual paints, the corresponding proportions of the pigment paste are taken and mixed with the dispersion, which is about one day old, in the manner mentioned in the above formulation, with slow agitation, and then (3 ) Add the solvents listed in ).

After complete preparation, pass the paint through a sieve.

This glossy paint is allowed to stand for one day and then applied to glass plates and steel sheets.

These root soils were previously sprayed with an air-drying glossy pigmented alkyd resin lacquer and after drying 10 hours after drying.
It was kept at 0°C.

A film applicator with a 200μ door slit diameter is used.

After a 24 hour drying time of the gloss paint, wet-adhesion is tested by two methods described below.

(1) Peeling test A mechanical peeling machine with a travel distance of approximately 1.20 m, as described for example in German Patent Application No. 2 262 956 - Gardner-Wacipilite and Applasion Machine.
sability and abrasion Mac
The prepared glass plate is placed on top of a glass plate in such a way that the applied dispersed paint film lies perpendicular to the direction of movement of the brush.

Due to the long travel distance, approximately 15 types of paint can be tested at the same time.

A boar bristle brush is used which is dampened with distilled water at the beginning of the test.

Distilled water is dripped during the test during the distance traveled by the plan, so that the brushing area is always covered with a film of water.

In the case of insufficient wet adhesion, after several transfers of the brush, the dispersed paint is brushed away from the substrate by the brush and a tear forms at the interface between the wet and dry film.

Wet adhesion is better the longer it takes for the brush to brush off the film.

Optimal wet adhesion is achieved after 3000 brushing steps (
One brush stroke is a round trip) if the film in the wet areas has not yet been brushed away.

(2) Condensation test In this case a rectangular thermostat is used which is half filled with water at 50° C. and in which a fan is installed in the gas chamber above the water level.

The upper opening is covered with a steel sheet - which has a test surface below - and thereby seals the thermostat.

The thermostat is kept in the room maintained at 23°C.

The temperature difference causes water vapor to condense on the underside of the sheet, affecting the glossy paint film.

After an impact time of 15 minutes in each case, the boards are removed and evaluated.

With insufficient wet adhesion, there is the formation of bubbles between the dispersion paint and the alkyd resin lacquer, and the film can be easily pushed away, for example with the tips of the fingers.

With good wet adhesion, the film has bubbles even after 4 hours and cannot be pushed away.

The test results are shown in Table 1.

Table 1 Example Peeling test Ivy in condensation test Number of brush strokes Durability > 3000 > 3000 > 3000 000 00 50 00 > 4 hours > 4 hours > 4 hours 2 hours 25 minutes 2 hours 70 minutes The present invention is claimed However, embodiments include the following.

(1) The method as claimed in the claims, wherein the addition of the halogen compound is started only when at least 40% and at most 80% of the other monomers have been polymerized.

(2) α that can be nucleophilically substituted with a suitable monomer in an aqueous medium in an amount of 0.5 to 10% by weight based on the total monomer amount.
・Copolymerization reaction with β-unsaturated halogen compound and 50
A dispersion paint with a low pigment concentration and a high organic solvent content, characterized in that it contains as a binder a synthetic resin dispersion obtained by the reaction of a halogen compound and ammonia at a temperature higher than °C.

Claims (1)

[Claims] 1 Synthetic resin dispersion obtained by copolymerization of a suitable monomer with a nucleophilically substituted α/β-unsaturated halogen compound in an amount of 0.5 to 10% by weight based on the total amount of monomers in an aqueous medium. is treated at a temperature above 50° C. with 2 equivalents of ammonia per equivalent of the nucleophilically substituted orogen or with such ammonia that the thermal dispersion exhibits a pH value higher than 8. or a dispersion paint, characterized in that the obtained synthetic resin dispersion is reacted at a temperature higher than 50° C. with 1 mol of urotropin per equivalent of rogene, and this is optionally made alkaline with ammonia. A method for producing a synthetic resin dispersion that provides high wet adhesion to.