Viscosity of acrylic paint din. What is the conditional viscosity of paint and how to determine it? What is the norm

Varnishes and paints for household pneumatic spray guns

According to the factory instructions for the Sturm SG9660 spray gun offered for rental:

"- max. paint viscosity 50 DIN

Nozzle diameter 2.6 mm...

Paints and varnishes suitable for use: water-soluble and other solvent-based paints, varnishes, primers, two-component paints, cleaners, car cleaners, sealants, preservative sealants, stains.

Paint and varnish materials that cannot be used: wall paints (emulsion), etc., alkaline and acid paints. Materials with a flash point below 21 °."

In fact, the factory instructions in one paragraph allow the use of any “water-soluble and other solvent-based” paints, and in the next paragraph prohibits any “wall paints (...) and the like.” One can assume such a contradiction by the subtleties of the work of Chinese translators from English (German) into Russian.

Studying the instructions for similar models of spray guns and the experience of their use gives the following recommendations:

- can be used with a spray gun, enamel and glaze (translucent glazes) paints, primers, oils, impregnations, varnishes on water based, water-dispersed, water-emulsion and solvent-based (white spirit, 646, 647, 450...) with a viscosity of up to 50 DIN, including: alkyd, acrylic (synthetic latex), two-component, antiseptics, stains;

- it is forbidden spray liquids that are aggressive to plastic and have abrasive components that wear out and clog the sprayer channels: gasoline, ammonia, paints with acid and alkaline thinners, polyurethane paints containing lead.

- not suitable for spray gun paints with difficult atomization and drop formation with a viscosity of more than 50 DIN, sparingly soluble, designed for application with a brush, spatula: thick emulsions, thick latex (styrene-butadiene), thick dispersion (glue, PVA), textured, silicate or liquid glass, hammer paint, enamels for metal, rust, wood oils.

Painting

Successful use pneumatic spray gun requires some skill, training and adjustment, preparation for a specific paint. Why take care of a supply of paint and solvent for test painting and washing the spray gun.

Follow the instructions on the packaging of paintwork materials and the tables in the factory instructions for the spray gun on diluting paintwork materials to the required viscosity using a viscometer from the spray gun kit and try painting, evaluate the result and adjust the viscosity, try again. For some paintwork materials, for uniform spraying, additional dilution is contraindicated or unnecessary; others, like some enamels, two-component paints, require additional filtration from large inclusions and undissolved clots. Moreover, filtration of paintwork materials may be required in preparation for painting and after thickening some time later. Assess the need for filtration based on the quality of the test paint surface.

Keep in mind that thinning the paint reduces its hiding power and it may be necessary to apply an additional layer; it is advisable to evaluate it on a test sample.

When working with enamels and glossy paintwork materials common mistake is neglect of filtering the air at the inlet to the compressor and keeping the channels of the spray gun and the air supply hose from the compressor to the gun clean. Regular cleaning of the compressor inlet filter will remove dust particles from the glossy layer.

It is better not to delay washing the spray gun for an hour or two, otherwise the paints will dry in the channels and body of the spray gun and dissolve or wash them off even with a strong solvent for a very long and difficult time. Some synthetic and organic paints and varnishes polymerize irreversibly or are chemically aggressive, eat into plastic and are no longer susceptible to solvents; it is preferable to apply such paints and varnishes with a brush, roller or metal spray gun.

Water-dispersion or water-based paints

Which is correct, water-dispersion or water-emulsion paints?

What is the difference between paint and enamel?

Dispersion is a formation of two or more elements that practically do not mix with each other and do not react with each other chemically. In this case, the first substance (dispersed phase) is finely distributed in the second (dispersion medium).

Emulsion is a dispersion system consisting of microscopic droplets of liquid (dispersion phase) distributed in another liquid (dispersion medium).

Thus, emulsion is one of varieties of coarse systems (in in this case liquid). Natural emulsions include, for example, milk, consisting of butter, casein and water.

Both dispersion and emulsion are a mixture of one small amount of substance with another. It is a mixture, not a solution, since the transition of molecules from one phase to another does not occur.

In the case of water-based paint, the first substance (synthetic polymers) is distributed in the second substance (in aquatic environment). Paint particles are suspended in water and equidistant from each other. When the paint dries, the water evaporates, and the particles come closer together and form a dense film on the surface.

Thus, the phrase “water-based paint” is not entirely correct, since emulsion means a mixture of precisely liquid elements with a liquid medium.

But no one pays attention to these nuances anymore. Just like the fact that, for example, a solution of cement with water and sand cannot be a solution from a chemical point of view, but is a suspension.

Suspension(lat. suspensio, literally - suspension, from lat. suspendo - suspend) - a mixture of substances where solid distributed in the form of tiny particles in a liquid substance in a suspended (unsettled) state.

You can also refer to GOST 28196-89, which applies to water-dispersion paints, which are suspensions of pigments and fillers in aqueous dispersions of synthetic polymers with the addition of various auxiliary substances (emulsifier, stabilizer, etc.).

However, GOST 28246-2006 indicates that water-dispersion paint is “a liquid or paste-like pigmented paint and varnish material that has a paint and varnish medium in the form of a dispersion of an organic film-forming substance in water and forms an opaque paint and varnish coating when applied to the surface to be painted.”

Classification of water-dispersion paints

In addition to pigments and fillers, water-dispersion paints contain a number of different auxiliary additives, but we are more interested in the type or substance (film former) by which all paintwork materials are classified.

Popular the following types water-dispersion paints, according to the nature of the binder:

Acrylic;

Silicone;

Styrene acrylic;

Acrylic silicone;

Vinyl acrylic;

Butadiene-styrene;

Polyvinyl acetate (PVA),

Polyurethane (quite rare and expensive on water, but the most durable and wear-resistant).

Acrylic paints

The binder (base) is polyacrylic (acrylic) latexes (polymers).

Advantages: due to their characteristics - strength, elasticity and durability, they are the most expensive of water-based paints. Acrylic paints are practically not afraid of the sun, water, and temperature fluctuations. Like other water-dispersed paints, they can be diluted with water, and after drying they become resistant to water. Suitable for both internal and external exterior finishing premises. Due to low gas permeability, they protect against corrosion reinforced concrete. Over time, acrylic paint pays for itself due to its durability and long term services. Can be used for outdoor work.

What is the difference between acrylic paints and acrylate paints?

Essentially it's the same thing. Acrylate polymerizes to acrylic. We purchase acrylate paint and apply it to the surface to obtain a coating in the form of an acrylic film. Thus, speaking of acrylic paint, we mean an acrylate binder.

What is the difference between acrylic paints and latex paints?

With the development of paint and varnish products, marketers have to come up with and introduce more and more new expressions into the product description, emphasizing the superiority of the product over competing analogues. Manufacturers often call waterborne paints polymer based latex. If natural latex is juice rubber plants, the synthetic latex used in paints is a dispersion of the polymers that make up the paint base. Therefore, the use of the term “latex” in the names and characteristics of paints is just tricky marketing ploy manufacturers to give their products additional benefits. Naturally, no one added any latex, the phrase “acrylic latex paint“It’s the same as “dairy butter” (although the example is not very good).

So a manufacturer can release 5 types of the same water-dispersion paint onto the market, calling the products, for example, latex, acrylic, acrylic-latex, acrylate, water-based paints(you can also more titles come up with, the main thing is to occupy the shelves in stores). And everything will be sold successfully. And the buyer suffers from the problem of choice. Usually famous brands they will not take such a step, as they value their reputation.

Glazing paints and impregnations

– translucent compositions on organic solvents or on water, interesting for protection and adding color wooden surfaces walls, floors, stairs, furniture. Can be used as a single coating or with additional protection varnish.

The composition of glaze paints includes polycrylate dispersion, water, as well as various chemical additives, natural oils. Consumption is about 100 grams per 1 square meter. Impregnations are sold ready-made colored or transparent, which can be tinted in almost any color according to the manufacturer’s tinting tables or using separately purchased dyes on the same base (aqueous or organic solvent). You can tint either manually yourself or by machine at points of sale. As a percentage, the amount of colorant should not exceed 100% of the total volume of the material, but in fact 3-10% is enough for a wide range of color shades. Colors according to factory tinting tables are obtained by mixing several colorants, but when choosing independently, a beginner only needs to use a colorant of one or two colors, for example, by adding white to lighten the second colorant. Tinting tables for mixing two or more colors yourself can be found on the Internet.

The time for complete drying depends largely on temperature regime and humidity indicators. So when high temperature(above +20 degrees Celsius) and low humidity, setting of the material can occur in just an hour. When working and drying in indoors With compositions containing organic solvents, it is important to create good ventilation.

Gloss level

The degree of gloss is measured as the amount (in %) of light specularly reflected from the surface in the total reflected light flux.

There are six gloss levels of paints and varnishes:
intense matte 1 - 10% gloss
matte 11 - 30% gloss
semi-matte 31 - 50% gloss
semi-gloss (or satin) 51 - 70% gloss
glossy (or bright satin) 71 - 90% gloss
high gloss - over 90% gloss.

To select and evaluate the gloss, you can do a test paint on a sample. For wood, keep in mind that glossy varnishes absorb less and create a thicker film, smoothing out roughness and hiding the texture. Glossy surfaces are more slippery, wash better, and emphasize surface defects or, on the contrary, the degree of evenness.

What is the difference between enamels and paints?

The difference between enamel and paint and what does “enamel paint” mean?

Initially, the term “enamel” meant a thin glassy coating obtained by high-temperature treatment of oxides on the surface of metals.

This is most likely how the term “enamel paint” appeared in the descriptions for compositions that form a strong, smooth film on the surface. Moreover, GOST 28246-2006 already directly indicates that the term “enamel” means “a liquid or paste-like pigmented paint and varnish material that has a paint and varnish medium in the form of a solution of a film-forming substance in organic solvents and forms when applied to the surface to be painted opaque paintwork". In the previous GOST 28246-89, the terms “paint” and “enamel” meant the same thing.

Thus, enamel implies a solution of a film-forming substance, in contrast to ordinary watercolor water or oil paint which do not have such properties and remain simply “paints”.

The difference between enamel paint and enamel covering metal utensils, for example, is obvious - these are completely different technologies.

High-quality painting is not only the result correct application coloring composition, but also a combination of certain characteristics of the material that determine decisions in this direction. When painting and varnishing, the key to success is the selection of such an indicator as paint viscosity in DIN. The table of optimal values ​​presented in this article will help in this matter.

The concept of viscosity itself hardly requires additional explanation. But here are some other characteristics that the conditional viscosity itself can influence:

• If the dye is too viscous, it will be difficult to distribute it evenly over the entire surface. Excessive layer thickness will result in too much drying time. The final strength of the coating, on the contrary, decreases.

The solution, which is thick in consistency, will not fill uneven surfaces. This means the grip gets worse.

• Large layer thickness is the reason for the formation of smudges and other similar defects.
• Finally, an inexpensive spray gun simply cannot cope with materials that have too high a viscosity. Main principle works for pneumatic sprayers - low pressure in the air stream, paint suction from the tank. They help those who are interested in how to determine the viscosity of paint.

If the pressure drop is not enough, the devices will have to be disassembled and then thoroughly washed. Paint diluted with additional effort is also harmful. Increases the number of layers required for high-quality processing. The time spent on this or that work increases, including those involving a spray gun.

Measurement Features

In what units?

For domestic producers It is typical to indicate this parameter in seconds. But imported materials require the use of a different designation - DIN. What meaning lies in these combinations? And how is the characteristic measured?

They are needed only to indicate the time (in seconds) after which the composition passes through holes of a certain diameter, known in advance. If the paint is more liquid, it leaves the container faster. In the case of a thick composition, this takes longer. This does not affect how to use the viscometer.

About methods and tools

Viscometer – special tool, used when measuring liquid, is a small funnel, strictly having a capacity of 100 milliliters. There is also a hole with a diameter of up to 4 millimeters. Instruments with sufficient accuracy for effective application in everyday conditions they cost from 200 to 500 rubles. They are used for routine viscosity measurements. Devices used in laboratories are much more expensive. Sometimes the cost reaches hundreds of thousands of rubles.

The instructions for using this device are extremely simple:

1. First you need to fill the funnel by plugging the inlet hole with your finger.
2. The stopwatch starts as soon as the hole opens.
3. All that remains is to record the time elapsed until the container is completely empty. Individual drops are not taken into account for paint viscosity in DIN, the table confirms this.

The temperature of both the paint itself and the surrounding air should not exceed 18-22 degrees. Any composition will thicken at lower temperatures. And when the indicator is increased, on the contrary, it decreases. Because of this, the experiment on paint viscosity will not be as effective.

On video: how to use a viscometer correctly.

What values ​​are considered optimal?

The manufacturer usually writes on the packaging about what indicator is considered optimal in certain conditions. But information is easy to find on the official website, including for viscous liquids.

If there is no viscometer, then you need to remember one more rule. Most paints are diluted to the consistency of liquid milk, unless the manufacturer himself has written about other conditions. The type of thinner must also correspond to what is written on the packaging. For example, nitro enamels are never diluted with water. For certain material your requirements are introduced.

Additional Information

Two-component dyes deserve a separate discussion. How to dilute these materials to the desired viscosity with your own hands?

• First, the paint is mixed with hardeners. The main thing is to strictly observe the proportions. Both deficiency and excess have a detrimental effect on quality.
• The viscosity level is checked separately. If necessary, use the appropriate solvent , maybe homemade.

If the volume is small, then measuring cups can be used for measurements. Measuring rulers also become indispensable assistants. But such methods will give accurate results only if accompanied by containers cylindrical. Even an ordinary bucket distorts the parameters, since it is made in the shape of a cone. Remember to use a paint sprayer with caution.

How to determine paint viscosity (2 videos)

What can be used (16 photos)

The viscosity of paint most clearly characterizes its suitability for use and its characteristics - color saturation, uniformity of coverage, brightness. The material should spread well, but not run off. This property also determines technical features application. There are several types of viscosity:

1. Newtonian. This type does not depend on shear stress, but on the nature of the substance, its temperature and pressure.
2. Effective plastic. For systems with an internal thixotropic structure.

Viscosity can be absolute (dynamic), relative and conditional.

Viscosity is characteristic property liquid materials resist the movement of one part of them relative to another during flow. Viscosity is one of the distinctive qualities of drying oil.

Depending on the composition and method of application to the surface (brush, roller or spray gun), paints must have a certain consistency, which can be determined using a viscometer. It is a cone-shaped funnel open at the top, pointing downwards, which has a hole at the bottom of a certain diameter.

This device measures the flow time of the amount of test liquid from a vessel with a special, calibrated hole.

The higher the viscosity of the drying oil or paint being tested, the longer the viscometer shows and, accordingly, vice versa.

The process of measuring the viscosity of paints and varnishes

Before checking, it is necessary to add 10-15% water (or solvent, depending on the type of paintwork) to the enamel. Let's dive measuring device into a container with liquid and simultaneously with raising the device, we note the time. The time during which the enamel completely flows out of the vessel through the hole is an indicator. You can use a regular phone or watch as a stopwatch.

The size of the opening of the viscometer used depends on the type of paintwork material. As a rule, it ranges from 2 to 8 millimeters. In total, there are about 40 types of these devices in the world, with different areas, hole sizes, geometries and volumes.

The most common viscometers are Shell, Zahn, B3-234 (they are used both for building enamels, paints or drying oils, and in the printing industry).

Good viscosity of high-quality drying oil and paint is considered at 22-24 seconds, but different types materials, these indicators may differ; this information can be found on the packaging (if not, you can check with the seller). Thus, a viscous drying oil can dry in 12 hours, and a more liquid one in 24.

Viscosity for thicker materials is determined with a ball viscometer (type 83). In this case, the time it takes for the steel ball to travel from mark to mark inside is measured. glass tube, in which the test material is located. This way you can measure the viscosity of old drying oil if it has become very thick.

1. It is better to measure the viscosity of drying oil and paint in a room with an air temperature of 20-23 0C, since in very hot or cold conditions, as well as in high humidity, the material can change its properties.
2. It is necessary to measure several times during painting and, depending on the results, control the consistency (in case of thickening, add solvent, in case of too low viscosity, increase the enamel content).
3. You should not take measurements when the enamel is foamed, as this will not give an accurate result.
4. If it is necessary to use a primer before painting, then the conditional viscosity of the primer is checked using a viscometer (it is better to use a device of the B3-246 series), the diameter of the meter hole in this case should be 4 mm, and satisfactory indicators should be 12-18 seconds.

Deviations from the norm

Any discrepancy with the parameters specified by the manufacturer may cause difficulties in applying the material. If the liquid is too viscous, it will make it difficult for it to pass through the spray gun opening, and the enamel will be applied unevenly to the surface. If the values ​​are too low, the enamel will drain from the surface, and streaks and unpainted areas may appear.

By measuring the viscosity, you can also check the quality of the material - whether any solvent was added to the paint by the manufacturer or distributors or not. Since some dealers may mix paint with a cheap, low-quality solvent, in order to reduce the cost of the material, as a good competitive advantage.

Cocktails are different, and not all of them are intended to be taken “on the chest”. Paints and varnishes that we use for restoration paint coating car - these are, in fact, also cocktails - properly prepared mixtures of several ingredients. And since we strive to ensure that the restored car (fender, door) after repair sparkles brighter than a new one, and the paint lies evenly, then our “paint cocktail” must be prepared competently, carefully and carefully, and not concocted anyhow.

Today you will find out

Ingredients

First of all, let’s decide on the type of our “paint cocktail”: will it be regular acrylic enamel (which is less likely), or metallic or pearlescent paint (most likely).

Regular acrylic enamel is two-component, with a hardener. The “ingredient kit” for such materials consists of three jars. For example, a liter of paint, half a liter of hardener and 100-150 ml of thinner. That is, when buying a liter of paint, you actually get about 1.6-1.7 liters of diluted paint.

In the case of “metallic”, the base paint is necessarily covered with a transparent varnish on top - without it, spectacular coatings look inconspicuous, and the weather resistance of two-layer coatings is much higher. Clear nail polish, just like acrylic enamel - two-component, with a hardener. But the “base” does not need a hardener - it is one-component.

Thus, the “set” for two-layer coatings already consists of five cans. For example, a liter of “base”, 500-700 ml of thinner for it, a liter of transparent topcoat varnish, half a liter of hardener and 100-150 ml of varnish thinner - a total of 3.3 liters! At the same time, the diluted paint itself was no longer there, the same 1.7 liters.

Making a batch

Before filling the gun, you should mix the components of the purchased paint.

For proper mixing of the components, which produces a painting material of the required viscosity, the following conditions must be met.

Dishes

It is important that the container in which we mix is ​​strictly cylindrical in shape (flat bottom and vertical walls). Only in such a container can you mix the components evenly and measure their quantities correctly.

It is better if it is a special measuring container in the form of transparent plastic jar with lid. Such cans are marked with markings that allow mixing materials in the required volume ratio (1:1, 2:1, 3:1, 4:1, 5:1, etc.).

Measuring containers are available in different volumes, ranging from 100 ml to almost half a bucket

Also, for dispensing and mixing paints and varnishes, it is convenient to use a special ruler with marks that determine the volume fractions of the components.

Pour the base into a cylindrical container to a certain division, and then add the hardener (if added) to the required mark, then the solvent. Mix everything with the same ruler - and you're done. Often, a measuring ruler is sold along with a set of paint, and all branded cans indicate the proportions according to these rulers.

It is convenient to measure the required amount of components using a measuring ruler. Then I chatted with the same ruler - and that’s it.

Proportions

Given the abundance that has reigned on the paint and varnish market, it is, as they say, impossible to give one recipe for all occasions by definition. Yes, and you don’t need to do this. There is TDS - you know who the rest is from.

However, it would be useful to provide some general guidelines. In principle, we already talked about them a little higher: up to 50% hardener and 10-20% thinner are usually added to two-component products. The degree of dilution of base enamels usually ranges from 50-80%. Well, look at the exact proportions in the instructions for a specific product: all can varnishes and enamels have instructions in the form of pictograms that inform you in what proportion you need to dilute the paint with the hardener (if the material is two-component) and thinner.

We remind you: only thinner is added to one-component materials (alkyds, base enamels, 1K primers); into two-component materials ( acrylic enamels and varnishes, 2K primers), first a hardener is added, then the mixture is brought to the desired viscosity with a thinner.

If you order paint for selection in a laboratory, then you will be given a set of components (usually ordered as a set), by mixing which you will get a ready-to-use material with a working viscosity - as they say, “for a spray.” Or they will give you paint that has already been diluted (of course, this only applies to the base, since the lifetime of two-component materials after mixing is strictly limited).

Supplements

A description of recipes for preparing paint cocktails would be incomplete without mentioning additives - materials used to change the individual characteristics of enamels, varnishes or primers.

For example, to create a rough surface - very often they are painted this way. plastic bumpers SUVs - there are structural additives of varying degrees of granularity. In general, to prevent paint on plastic from cracking, 20-40% plasticizer must be added to it. There are matting elasticizers designed to reduce the shine and color of plastic parts such as side trims on Mercedes-Benz cars.

When painting with spectacular two-layer coatings, these additives must be mixed with the topcoat varnish (it is recommended to add a plasticizer to the filler primer as well). Read more about additives and their use.

Measuring viscosity

Any painter should be able to control such a vital important indicator, like viscosity. For what? So that it corresponds to the recommended value. Again, why? To evenly apply the material to the surface and obtain a coating required thickness with the intended properties - beautiful and durable.

“Viscosity” (from Latin viscosus - sticky, sticky) is a value characterizing the fluidity of a liquid.

For what?

Filtering

The prepared paint and varnish material must be filtered before filling into the spray gun tank, since it may contain foreign inclusions that got there during the preparation process, clots, etc. Otherwise, guarantee receipt high-quality surface This is not possible, because all this debris may ultimately end up on the surface being painted.

For filtration, it is convenient to use disposable paper funnels with a nylon filter insert (mesh size, usually 190 microns). I inserted the funnel directly into the tank, strained it - ready, you can paint!

We fill the paint tank only using a filter funnel.

Basic mistakes

Achieve consistently High Quality The work performed is possible only if technological recommendations for the use of certain materials are observed. There is simply no other way for those who want to repair modern cars and repair them efficiently.

Meanwhile, ignoring technological requirements remains the main (!) cause of defects and errors. As they say, “...how many times have they told the world”...

But “free morals” have always been and will be: we adjust the spray gun “by ear”, we mix the paint “by eye”, we forget about the strictly defined “lifetimes” of products prepared for use.

For example, in an hour the varnish changes its viscosity by an average of 100%. It's thickening. Before lunch we stirred it, measured the viscosity - 20, went away to eat satisfied, returned 50 minutes later, and it was already at 40! Of course, the material can no longer be used. But how often does anyone consider such “trifles”?

How often does anyone remember that a material into which we have not added enough hardener will no longer be able to properly harden, no matter how dry it is. Acrylic two-component materials are cured in the same way: due to a chemical reaction between the acrylic binder (base) and the substance for cross-linking molecules - polyisocyanate (hardener). And only the paint manufacturer can know what number of -N=C=O units (present in the hardener) is necessary to react with a certain number of OH units (found in the base) and transform the material into a durable polymer film (more on this).

So it turns out that if we do not pour enough hardener, there simply is not enough crosslinking material to properly cure the film. The coating is soft and uncured.

The opposite situation - with an excess of hardener (and, accordingly, an excess of -N=C=O units) has the opposite effect - the coating turns out to be too hard, but at the same time inelastic, highly susceptible to peeling, cracking, and chipping.

So if the can of varnish says to dilute it in a ratio of 2:1, then you need to take the time to measure exactly two parts of varnish and one part of hardener. No more, no less.

Correct polymerization of two-component materials is possible only if the correct mixing proportions with the hardener are observed

Well, what to confirm acrylic materials it is possible only with original hardeners - it is not subject to discussion at all. In acrylic systems, the copolymer and polyisocyanate are carefully selected for each other, and if we take a hardener from another varnish or another manufacturer, we will get a different polymer with completely different properties.

The jar with the remaining hardener must be tightly closed, since the hardener reacts with air moisture, resulting in its cloudiness and loss of crystals, sometimes gelling. To prevent air from entering the partially used can of hardener, it is recommended to turn it over and place it on the lid, and store it in this position.

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