CS234516B1 - Water dispersed coating composition for surface finish of flexible synthetic band materials - Google Patents

Abstract

BACKGROUND OF THE INVENTION The present invention relates to improving the processing properties of aqueous dispersion coating compositions for poromers and other flexible synthetic sheet materials. The coating composition according to the invention contains 0.3 to 16 wt. a poly acrylate thickener, 0.05 to 0.3 wt. % ammonia, 0.7 to 1.3% by weight of casein, 1.5 to 11% by weight of casein; pigment, 1 to 5% (non-ionic surfactant by weight, two of the non-irradiated polymeric binders, including acrylate-butadiene copolymer, thermoreactive acrylate-styrene copolymer, copolyacrylate and polyurethane, wherein the two polymer binders, in a weight ratio of 1: 4 to 4: 1, optionally, melamine-formaldehyde precondensate, waxes and water The coating composition may comprise casein and pigment preferably in the form of a cassein pigment preparation in which the dry matter is comprised of 9 to 30% % by weight of the casein and 91 to 70% by weight pigment, which is prepared by dispersing and homogenizing pigments and optionally fillers in a colloidal alkaline aqueous solution of casein with additives such that the resulting solution has a concentration of 30-60% by weight.

Description

The present invention relates to aqueous dispersion paints for surface treatment of flexible synthetic sheet materials, in particular polyurethane-based poromers.

Treatment systems for flexible sheet materials can be solvent, but also classic - water-dispersive. · For poromeric synthetic leather, a combination of both types is very often used. The colored base layer of the surface treatment is in this case formed by applying water-dispersive paints in one or more times in multiple coats. The solvent system of the finish paint is applied on it ·

In the continuous production process, in addition to the end-use properties, the processing properties of the treatment systems for the individual coating layers are equally important. The goal of component selection and final formulation of treatment systems must be risk-free, reproducible production.

Aqueous dispersive coatings formulated on the basis of aqueous dispersions of suitable polymeric binders are complicated colloidal systems whose stability is largely sensitive to external conditions, for example · during preparation and processing on coating machines · Most often they are:

- a roll coating machine for applying a major proportion of the weight of the colored paint;

- a spraying machine, which is used to cover frequent defects from cylindrical application - scratches, air bubbles with. - and for the final leveling of the color shade ·

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- vytvořeníTo produce a high-quality color base coat, it is essential that the coating has optimal processing properties. The most important processing properties include:

- perfect mechanical and electrolytic stability

- stability against separation of pigment mixtures

- good flowability

- low foaming

- the possibility of controlling the weight of the coating on the application device.

The processing properties influence the quality of the coating and thus can significantly affect the utility properties of the coating. With regard to the final quality of the color coating and the economy of production, the basic processing properties of the coating material for these types of coating devices are associated with the problem of flow, i.e. creating a continuous smooth, level, layer of wet paint.

The flowability of the paint is an important requirement for achieving leveling and optimum coating weight, especially in continuous production conditions. This quality parameter includes two basic aspects:

and - interfacial properties, i. interactions between the surface of the substrate being treated and the surface of the applied paint layer;

b - flow properties expressed in theological characteristics, which require a more detailed breakdown.

Water dispersion paint systems have the character of non-ionic liquids. They are characterized by a pronounced structural viscosity, which means that the viscosity values depend to a greater or lesser extent on the shear stress or shear rate.

The viscosity value measured at the selected shear stress or shear rate is referred to as the apparent viscosity.

An important theological characteristic of structurally visacous systems is the value of the so-called resting viscosity; it means the viscosity value that the coating system achieves in the zero environment

234,516 shear stress - that is when the system passes through the applicator and is spread over the substrate.

However, in many systems, it can be observed that creep occurs only when a certain shear stress value ^r _Q - is exceeded; this property of the liquid system is called plasticity.

Theological anomalies, which can sometimes significantly influence the course and quality of application, especially the flowability of the Řthree mass, include thixotropy. In this case, the viscosity of the system depends not only on the shear rate, but also on the time-viscosity decreases with the constant shear stress.

When evaluating the parameters of coating systems for coating, the mechanical components must also be considered: elasticity of the liquid system, tensile strength and elongation of the fiber drawn from the liquid system.

The drip resistance is mainly related to the elasticity value of the liquid system. The high elasticity and elongation of the fiber cause the apertures of the application roller to draw the fibers of the coating composition. In this regard, coatings with low resting viscosity values are preferred because they do not allow the formed fibers to be fixed to the substrate.

of relative importance. There are some contradictions between the surface and theological aspects. However, it is generally stated that it is primarily theological aspects that control the application phase in the coating of substrates. E.g. the formation of wet film is influenced by any viscosity value in the region of relatively low shear stresses in any application - roller, knife, spray, brush or combined. The indicator here may be the resting viscosity value. The formation of a wet film, of which good quality is a prerequisite for realizing single-layer top coatings, depends at the same time on the spreading and layering capability and resistance to formation of defects in the wet coating of air bubbles, scoring and other damage.

- 4 ·

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Systems with a pronounced structural viscosity, whether with a tisotropic nature or with high flow limit values, are preferred for application to highly absorbent materials (e.g., textile); after application, their resting viscosity increases to very high values, the system loses its fluidity and thus avoids deep penetration or decorative printing maintains perfect contour sharpness ·

Systems with opposite theological characteristics - β of low structural viscosity, low resting viscosity value, no thixotropic effect and low flow limit values are more suitable for low absorbency substrates and for full-surface deposits, including for the treatment of synthetic leather.

Aqueous component dispersion paints for basic color layers contain a large number of components with specific effects · The basic component here are polymeric binders in the form of aqueous dispersions, most often based on polyacrylates, polyurethanes, copolymers of acrylates with other monomer components such as butadiene, acrylonitrile, styrene. In addition, these coatings comprise inorganic and / or organic pigments, dyes and special auxiliaries for adjusting performance and / or processing properties; they are, for example, surface-active substances, crosslinking agents, defoamers, viscosity regulators, touch-adjusting agents, and, in particular, surfactants.

The coatings for the base color layer of the poromer coatings are therefore complex and sensitive colloidal systems, and their stability decreases as the number of components increases.

Mixtures of two or more polymeric binders are often required to achieve optimum surface finish performance. The coloring components impart a certain amount of surfactants to the system and, moreover, they can sometimes affect the rheological characteristics of the coating. Thickeners are most commonly used in polyacrylate because of their high efficiency - so they do not need to be used in excess, so they do not negatively affect the wicking values and do not increase the stiffness of the polymer film.

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However, rheologically they are usually characterized by extreme structural viscosity and infinite high value of resting viscosity - plasticity. »Other components such as crosslinkers, surfactants, stabilizers, waxes, silicone compounds and others increase the complexity of the system.

Due to the interaction of individual components in such complicated systems, supramolecular structures are formed which influence the properties of the continuous medium: the cohesive strength of the system increases, the rheological characteristic changes. The features of these systems are not additive and cannot be predicted due to the number of components. The mutual behavior of the components may even be anomalous to the extent that the real properties and behavior of the system differ substantially from the theoretical assumptions.

In terms of rheological characteristics, these coatings are systems having:

- a relatively pronounced structure-viscosity character, i.e.. a rapid viscosity gradient with an increase in shear stress, which is expressed by relatively high angle tangent values and flux index values;

- very high resting viscosity values;

- viscoplastic character with limited flowability and flow limit;

- for some formulations, in particular depending on the type of polymeric binder and pigment preparation, thixotropic behavior, in some cases a hint of reopexia;

- relatively high ductility and tensile strength values.

The unfavorable flow properties of these coatings further deteriorate in relation to the quality of the coated substrate or when a particular application method is used. The almost compact, closed polyurethane surface of the untreated poromeric material is characterized by an extremely low surface energy value, sometimes referred to as the critical surface tension of the solid surface, which is about 27 mNm @ -1. For comparison, for polyethylene, which is referred to as a particularly hydrophobic material, this value is about 31 mN.m "

234 516 active substances to achieve such low surface tensions in the liquid system and since the effect of interfacial effects is quite suppressed due to the real consistency of used paints, then the demands on favorable rheological characteristics of paints are justified

The consequences of the adverse flow properties of current water-dispersive coatings for the surface treatment of synthetic poromeric leather are;

For cylindrical application:

- A high resting viscosity value does not allow the defects in the wet coating to heal quickly enough due to either the writing of solid particles or the grooving of the blades. The imperfect quality of this layer requires an additional leveling layer, usually by spraying »

- Relatively low solids content does not allow under the current operating conditions to achieve the weight of the color layer required to form single-coat top coatings »

For application by rotation:

- Paints have a lower dry matter content, but have a relatively higher content of polyacrylate thickener than roller coating. When passing through a spray gun nozzle, the paint is subjected to a high shear stress so that at this stage it has a relatively low apparent viscosity, which is a prerequisite for fine particle dispersion. »During flight, the atomized particle loses some of the liquid phase by evaporation, increasing the dry matter content in the drop;

In the coating composition, the strength of the interaction and hence its structural-viscous character is increased. Upon impact on the substrate, the high shear stress ceases, the viscosity value rises considerably, except for the resting viscosity, so that very unfavorable conditions for droplet flow and their connection into a continuous leveling layer are created.

Particularly unfavorable, anomalous behavior of paints containing blends of certain types of water-dispersed polymer binders has been observed. For example, using a mixture of a polydisperse binder acrylate-butadiene copolymer with a monodisperse copolymer

-> 234,516 acres lát- styrene having a force liable to confusion groups should Ly "bow w ¹ Star-via SLittasJi during spraying so severe that it was impossible to create a level vstvu perfectly. In this case, the flow characteristics were adversely affected most likely by the differences in the geometrical arrangement of the solid phase of the two aqueous dispersions. Although the utility properties of the surface binder of this binder mixture were satisfactory and their use would be more economically advantageous, this mixture could not be realized in the paint due to the unmanageable processing properties »

It has now been found that there are substances which can advantageously alter the processing properties of a liquid colloidal system applied as a coating composition.

The unfavorable processing properties of the hitherto known coatings for the coating of flexible synthetic sheet materials, in particular polyurethane-based poromers, are greatly improved with the water-dispersive coating composition according to the invention.

SUMMARY OF THE INVENTION The present invention relates to a coating composition based on polyacrylates and / or copolymers or mixtures thereof with other acrylates, butadiene and / or styrene, containing pigments, Darviva, thickeners, surfactants, defoamers and other paint additives, containing 0 3 to 16¾ wt. % polyacrylate thickener, 0.05 to 0.3 wt. ammonia, 0.7 to 1.3% by weight of casein,

1.5 to 11 wt.% Of a pigment; 1 to 5 wt. neionogenni. surfactants, two of the group of incompatible polymeric binders comprising acrylate-butadiene copolymer in an amount of

2.3 to 13.8 wt.%, Thermoreactive acrylate-styrene copolymer in an amount of 4.6 to 14 wt.%, Copolyacrylate in an amount of 2 to 10 wt. and polyurethane in an amount of 2 to 3.2% by weight, wherein the selected two polymeric binders are in a weight ratio of 1: 4 to 4: 1, further optionally 0.002 to 0.2% by weight. 0.4 to 0.9% by weight of melamine formaldehyde precondensate and 0.4 to 0.7% by weight of an antifoam; % of the waxes, the remaining proportion of which is up to 100% by weight of the paint is water. The coating composition preferably comprises casein and a pigment in the form of a casein pigment preparation in which the dry matter is comprised of 9 to 30% by weight. casein and 91-70 wt. % of a pigment, and which is prepared by dispersing and homogenizing the pigments and optionally fillers in a colloidal alkaline aqueous casein solution with additives such that the resulting solution has a concentration of 30 to 60 wt.

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The following indicators are used to quantitatively describe the processing properties of the coating composition according to the invention:

The line representing the viscosity (or shear rate) on the shear stress in logarithmic coordinates forms an angle ° ^ with the axis of the shear stress values and the tangent of this angle indicates the rate of decrease of viscosity (or shear speed) with shear stress. .

The resting viscosity value was determined at the indicated logarithmic weight. extrapolation to zero shear stress.

The flow limit - the shear stress value at which the system creeps - was determined from the graphical dependence of the shear rate on the shear stress as the intersection of the ascending linear portion of this dependence with the shear stress axis.

In practice, the structural viscosity of a system is often expressed by the flow index - a ratio of the apparent viscosities measured at lower and higher shear rates, usually at a ratio of 1:10 or 1:20. The apparent viscosities measured by a Brookfield RVT viscometer at 1 and 10 rpm were used to calculate the flow index. min ».“ ¹ measuring spindle.

The thixotropic character was evaluated from the area of the hysteresis loop, which was created when measuring the shear rate dependence on the shear stress from zero to maximum and back in a defined time program.

The ductility and tensile strength values were determined from the mechanical properties of coating systems for coating flat materials. The tensile strength of the liquid column was determined on an Ai Nouy instrument used to measure the surface tension. A circular plate mounted on torsion wire was used to measure the tensile strength. The force required to tear off the plate from the paint level was determined by the weight of the weight needed to balance the plate back to its starting position.

Jansson's principle was used to determine the ductility: a metal plate that was placed exactly on the surface of the test

- 4 234 516 of the paint, was moved evenly by a strong upward pull · A fiber formed between the plate and the paint surface and its length in mm was determined at the moment of breaking ·

When investigating the effect of modifying components on the processing properties of paints, a paint without modification was first prepared. Casein as a modifying component was then added to the paint used for the base color coating of poromer coatings and applied on a roller machine. 673 013) was adjusted to approx. 20 s with a polyacrylic thickener and ammonia water. The following quantities were determined: angle //, resting viscosity value, comparative apparent viscosity and flow index value

1 ^ 0 and flow limit value (2 ^ ·

Table 1 shows the effect of these substances on the observed rheological variables.

Table I

casein content (% wt) £ gnzieten- rheological variables (deg) 7, (mPaS) ^ 0 (mPaS) bo (dyn.cm) - 20.8 74 10880 1,14.10 ⁹ 5.74 47.5 2.5 20.6 38 1860 6,84.10 ³ 2.82 19.5 6.3 20.4 26 920 1,62.10 ^ 1.92 13.5

A comparison of the θ4 values, the resting viscosity / 7, and the 6Γ _θ flux limit indicates that casein has a significant effect on suppressing the pseudoplastic nature of the flux and reducing ^ ₀ values, even at relatively low concentrations in the system (ή!) 234 516

Casein belongs to the group of high-molecular proteins - proteins. The macromolecular chain contains peptide groups on which, by the action of, for example, formaldehyde, or substances containing methylol or N-alkoxymethylol groups, or by the action of other substances, transverse methylene -C 1-6 bonds are formed; this fixes and suppresses the solubility of casein film ·

In an alkaline environment, casein dissolves to form a colloidal solution. · Rapidly undergoes a degrading effect of bacteria, so solutions must be preserved. Organic compounds such as parachlormethacresol, nitrobenzene, phenol, and phenol are most commonly used.

Casein produces relatively hard films; its applicability in coating systems intended for coating flexible sheet materials such as poromeric leather is therefore limited. on the composition of polymeric binders, on the casein content and on the degree of cross-linking - fixation.

It has been found that up to 15% of the casein dry matter, based on the total dry matter of polymeric binders in the coating material, can be added in coatings for surface treatment of flexible sheet materials, depending on the composition of the coating system.

It has further been found that casein can be added in various forms. All are based on an aqueous alkaline colloid casein solution with a preservative. It may contain other auxiliaries such as waxes, emollients, skin glue, surfactants and possibly others. are, for example, barium sulfate or aluminum hydroxide in an aqueous alkaline colloid solution of casein with preservatives and containing the other aforementioned auxiliaries.

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Casein solution with β additives has been used to optimize casein content in the paint. Furthermore, it has been found that casein acts as a modifying component in paints which contain mixtures of polymeric binders of various properties and are used in varying proportions (ratios) so significantly that the processing properties of the modified paints are very close to each other.

In view of the economics of production, the use of casein pigment preparations is particularly advantageous since two technological operations can be combined: the casein pigment preparation both as a coloring agent and as an effective modifier.

The results shown in Table II on the next page show the effectiveness of the pigment preparation for paints with particularly pronounced internal interactions.

Two different blends of polymeric binders were used for the preparation of paints:

Mixture A - butyl * acrylate-acrylonitrile copolymer with acrylate-butadiene copolymer in a weight ratio of 1: 1

Mixture B - thermoreactive acrylate-styrene copolymer with acrylate-butadiene copolymer in a weight ratio of 1: 1 ·

Pigments used:

P - pigment in shade ocher - iron oxides

S - pigment mixture in ocher * brown - iron oxides.

Modification systems used:

KPP - casein pigment preparation

K + P - liquid solution + pigment

KP + P - casein solution with additives ♦ pigment

Modification systems are specified in more detail in individual examples.

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VI (B VI -P * UJ rv H CK 0 Ό what O o (B) ttí ω what 00 5 » t_i. h ax Η · Κ < what <B O Ό H · bi bi ω ω bi bi Φ O c + 1 with MS W MS IV B I.E + T7 O O • tí + bi 1 < Oj bi ffu p. 3 O W 1 / - »<+ fV H IV H H H ω Φ O KO KO O Ό KO 00 3 w 40 40 40 40 40 O N uj IV IV rv O 00 ro H · ω t Okay rv IV rv UJ VI Qj JV UJ -4 O -4 IV (D 40 40 04 / 40 O AND-* O O O O H c + 40 40 40 40 40 «0 04 / 00 vi UJ -4 IV 00 IV IV -in Okay 00 z-> VI H UJ and rv Okay \O VI 4 * · rv 00 4 * O AND O -Ρ » C04 O O O O O O • VI H UJ & TO H UJ KO fd 00 00 -4 -4 • Ρ » O Uf Γ4Ν ok vn Okay Okay 00 WHAT O O O O —4 O vz H IV H UJ φ- H w M 40 <0 w 40 H Ό ko H 00 O H O 00 O IV -4 rv 00 O. UJ H (IN «< O -IN 1 1 IV rv 0 40 40 4 · * O IN/ O O VI O O Q ' (B) v-z O O O bi 40 40 1 1 40 M & H -4 00 KO 0 . O Ό H ~ 4 H she knows O 1 rv KO Okay Okay 00 40 40 1 1 40 «0 tv> O O H (3 _

Table IIi Summary values of properties of unmodified and casein-modified paints

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In the polymeric binder mixture B, stronger interactions can be confirmed between the components, which are expressed by a very high resting viscosity value as well as other mechanical values and rheological characteristics; these are so unfavorable in this case that the coating composition containing this binder mixture cannot be applied, for example, by spraying. The relatively small addition of the casein modifier resulted in a significant suppression of the internal structures and thus an increase in the mobility of the layers, an improvement in flow properties and flowability of the paint after application to the treated substrate. As a modifying additive, casein also has the ability to completely eliminate the thixotropic character and further improve the creep flow in the region of very low shear stresses by suppressing the flow limit. Casein further _<lowers mechanical properties; the liquid fiber loses its elasticity, and in particular in the case of a roll coating, the coating composition is better separated from the application roller and passed on to the coated substrate.

The use of casein in the paint has other beneficial consequences. The dried casein layer has a hydrophilic character; this significantly improves the wettability of this layer and the flowability of other applied coatings. On the Gontact Angle Analyzer, the contact angles Φ of the paint droplets were measured and found to be markedly lower when applied to a casein-coated paint layer than when the same paint was applied to a casein-free color coat.

For multi-layer coatings, the conditions for creating a high-quality color coating of the surface treatment are improved by adjusting the rheological characteristics as well as by improving the inter-surface ratios.

Also important is the contribution of casein to increasing the water vapor permeability values through the polymer film. When evaluating separate polymeric binder films, it has been found that the addition of casein increases the water vapor permeability values of pigmented films by 20-30.

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Addition of casein ▼ above 11% by weightA% significantly increases the wetting values of the polymer film, and this adversely reflects the low wet abrasion resistance of the coating.

It has been found that casein fixation can be carried out simultaneously with crosslinking and tensoreactive polymeric binders by the addition of compounds with, for example, methylol or N-alkoxyethyl groups, optionally containing free, residual formaldehyde. 10% by weight, based on the total dry weight of polymeric binders · The sieving and fixation reactions take place when the material is exposed at temperatures of 130 to 140 ° C for 2 minutes ·

The coating composition according to the invention is prepared by first preparing a thickening salt from water-dispersing thickeners based on polyacrylates and from an inorganic or organic base, preferably from ammonia water; once the viscosity has stabilized, either the pigment preparation and the aqueous alkaline colloid casein solution with a preservative and other excipients such as waxes, emollients, surfactants and others are added to the thickening salt, or a casein pigment preparation can be added (optionally adding The aqueous dispersion of polymeric binders and the necessary auxiliaries such as surfactants, antifoams, sieving agents, and possibly others are mixed in. The optimum viscosity for the selected application method is controlled by the thickening salt content.

The preparation of the coating composition can also be carried out in such a way that the thickening is carried out as a last operation without prior preparation of the thickening salt: inorganic or organic base, preferably ammonia water, and added to the mixture with all the above components the paint had a pH of 7- * 10 «

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The use of the modifying additive according to the invention in coatings for the surface treatment of flexible flat materials, such as poromeric and other synthetic leathers, in a continuous manufacturing process brings significant advantages in the technology and economics of production. Casein modification has a very beneficial effect on the processable properties of paints and allows:

- to realize formulations of paints that contain raw materials which are economically very advantageous, but are not really usable in terms of processing properties. In this way, the field of usable raw materials can be significantly expanded, eg to domestic sources;

- to combine two technological operations and functions - case dyeing and modification - using casein pigment preparations;

- good quality of coatings from modified paint create conditions for simplification of technological process of surface treatment by possible removal of additional leveling of color shade by spraying.

In order to further elucidate the invention, there are some examples of modified paints.

Example 1 - Comparative

Casein-free standard formulations for roller application; it is given to illustrate the effectiveness of the modification process. The consistency of the paint is adjusted using a pre-formed thickening salt.

demineralized water polyacrylate thickener (40 wt.%) antifoam ammonia water (25 wt.

48.00 parts by weight 3.26 nh ₃ )

0,002

The 0.80 thickening salt is left to stand for 1 hour, then the casein-free pigmented preparation (50% homt.) Is added. 15.60 aqueous dispersion of acrylate-butadiene copolymers (46% by weight) 23.30

- 1C 234 516 aqueous dispersion of butyl acrylate-acrylonitrile (40% by weight) 7.80 parts by weight non-ionic surfactant (10% by weight) 1.30 The prepared coating composition is applied to a poromeric substrate on a roller application equipped with an air blade for additional leveling of the coating weight.

After drying, the colored layer shows defects (scratches, air bubbles etc.) - an additional correction spray must be applied. The rheological characteristics of the paint are given in the table; II, row 1.

Example 2

Formulation of modified paint for roller application; In comparison to Example 1, the casein-free pigmented preparation in the coating formulation is replaced by the casein-pigmented preparation in an equivalent amount. The other components are retained as in the formulation of Example 1.

The modified paint has markedly poor processing properties. The favorable change in rsological characteristics induced by the addition of casein is evident from Table II - see No. 2 in comparison and No. 1. The color coating is significantly better, defects occur sporadically. If the color layer is sufficiently opaque, no additional spraying is required.

Example 3 demineralized water 50 parts by weight

polyacrylate thickener defoamer (30% by weight) 2.50 0.20 Ň N W toned blend of opaque, transparent pigments (20 % by weight) 3.00 M N caséine solution (18 % by weight) 5.00 H W an aqueous dispersion of butyl acrylate acrylonitrile copolymer (40 % by weight) 23,00 N H aqueous polyurethane dispersion (40 % by weight) 7.00 H 1 « surfactant (20 % by weight) 5.00 « w wax dispersion (15 % wt.) 3.00 W

234 516 water-soluble melamine pre-condensate (60% w / w) 1.30 parts by weight ammonia water (25% w / w) quantity to adjust to pH 7-8

The modification is carried out by additional casein addition to the preparation of opaque transparent pigments. The coating composition is applied on a roll coating machine; the subsequent leveling of the wet deposit weight is carried out using a suitable spiral blade so that the final deposit weight is in the range of 60 - 80 g. See Table 3 in Table II for rheological characteristics.

Example 4

Formulation of coating material for single layer topcoat

demineralized water polyacrylate thickener (40% by weight) 30.64 parts by weight 2.09 parts by weight defoamer, 0.02 H 99 tinted pigment preparation 17.70 th 99 without casein (36 % wt.) aqueous alkaline colloidal casein solution, preserved with waxes, emollients (20 % wt.) 6.76 19 Dec 99 aqueous dispersion of thermoreactive acrylate-styrene copolymer (46 % wt.) 17.90 99 99 acrylate-butadiene (46 % hmo t o) 17.90 99 99 nonionic, surface active substance (10 % wt.) 1.53 99 »9 water-soluble melamine- formaldehyde precondensate (60 % wt.) 0.75 1 « 99 wax dispersion (15 % wt.) 4.51 « W ammonia water (25 % hm.NHj) quantity k : nasta vení pH 8- Ί0

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The coating composition is applied on a roller machine equipped with an air blade of 60-80 g.m. A high-quality coating with a higher dry matter content (compared to the coating of Example 2) does not require additional correction spray coating. See Table 4 for rheological characteristics. II.

Example 5

Spray paint. It is additionally applied to the colored base layer formed on the roller applicator (see Examples 1, 2).

demineralized water polyacrylate thickener ammonia water thickening salt is allowed to stand, dotted casein pigment preparation thermoreactive acrylate-styrene copolymer acrylate-butadiene copolymer non-ionic surfactant water-soluble melain adds

(40 ^, wt%) (2 ^ 6hmotoNH ₃ ) 57.70 3.70 0.90 hmoto 11 n parts «1 11 (44% by weight) 12.00 n n (46% by weight) 18.00 tt « (46% by weight) 6.00 11 11 (10% by weight) 1.00 11 · » (60% by weight) 0.70 11 11 effect thermal exposure

(130 ^w - 140 ů / 2min.) Simultaneously crosslinking the thermoreactive poles of the specific binder and the casein fixation.

By modifying the coating composition, such an improvement in the flowability of the coating is achieved that the color layer is perfectly homogeneous and color level.

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When applied without the casein modification component, the cohesive forces of this combination of polymeric binders are so high that the fine droplets do not bond and the resulting layer does not significantly fill them in color.

Differences in values of mechanical properties and rheological quantities are apparent from Table II - rows 5, 5a; the modifying additive produces particularly pronounced changes in the structure-viscosity characteristic - the value of the angle tk or případně ^ θ - and the value of the resting viscosity.

The effect of the invention is most pronounced here - in this combination of polymeric binders, the original rheological characteristics are so unfavorable that the coating composition without modification cannot be used for spray application.

Example 6

Formulation of coating material for single layer topcoat

Jl deposit demineralized water polyacrylate thickener (40 wt%) ammonia water tinted pigment preparation with casein (43 wt%) water-dispersed acrylate-butadiene copolymer (46 wt%) water-dispersed thermoreactive acrylate-styrene copolymer (46 wt%) nonionic surfactant aqueous solution of melamine formaldehyde precondensate (60% w / w)

10.0 parts by weight

0.9

0.2

28.1, 28.1

30.1

1,2

1.4

The application is carried out as described in Example 4. The rheological characteristics of the coating composition are shown in Tab. II, No 5.

Claims (2)

Water-dispersive coating material for the treatment of flexible synthetic sheet materials, in particular polyurethane poromers, based on polyacrylates and / or copolymers thereof or mixtures with other acrylates, butadiene and / or styrene, and further comprising pigments, dyes, thickeners, surfactants, defoamers and other paint additives, characterized in that it contains 0.3 to 16 wt. of a polyacrylate thickener, 0.05 to 0.3% hmox. % ammonia, 0.7 to 1.3 wt. % casein, 1.5 to 11 wt. % pigment, 1 to 5 wt. nonionic surfactants, two of the group of incompatible polymeric binders comprising an acrylate-butadiene copolymer in an amount of 2.3 to 13.8% by weight, a thermoreactive acrylate-styrene copolymer in an amount of 4.6 to 14% by weight, a copolyacrylate in 2 to 10 wt. and polyurethane in an amount of 2 to 3.2% by weight, wherein the selected two polymeric binders are in a weight ratio of 1: 4 to 4: 1, further optionally 0.002 to 0.2% by weight. % antifoam, 0.4 to 0.9 wt. % of melamine formaldehyde precondensate and 0.4 to 0.7 wt. % of waxes, the remainder being up to 100 wt. Paints are water. 2. A water-dispersive coating composition as claimed in claim 1, comprising casein and a pigment in the form of a casein pigment preparation in which the dry matter is comprised of 9 to 30% by weight. casein and homogenizing the pigments and optionally fillers in a colloidal alkaline aqueous casein solution with additives. The resulting solution has a concentration of 30 to 60% by weight.