A quick overview of paint performance detection methods!

Raw paint performance testing refers to the quality of the coating packaging, after transport, storage, until use. The main performance is as follows.
in the container:
through visual observation of the paint layering, murky, thickening, collation, skin, precipitation and other phenomena

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(1) layering, precipitation: coating after storage may be layered phenomenon, generally can be checked with a scraper, if the sediment layer is soft, easy to insert with a scraper, precipitation layer is easy to be stirred up and dispersed, paint can continue to be used.
(2) cortical: aolic acid, phenolic, natural oils and other coatings often produce cortical, cortical layer can not be used, it can be removed after the lower layer can continue to use, use should be stirred evenly.
(3) thickening and collification: can be stirred or mixed with a moderate amount of thinner for use;
density:
weight per unit of volume of an object at a specified temperature. The measurement is carried out according to GB/T 6750-1986
fineness:
the degree of the coating solid material. Fineness has a great influence on film quality, paint film gloss, durability and coating storage stability. But it is not the finer the better, too small will affect the adhesion of the paint film. Measured by GB/T 1724-1979 (89).
viscosity:
represents a project of fluid flow and deformation under external force, a measure of the internal resistance of the fluid to the flow, also known as an internal coefficient of friction. The detection methods are:
(1) outflow method: suitable for transparent varnish and low viscosity paint detection. That is, the viscosity of the coating is expressed by the time it flows out of the container with a certain volume.
(2) drop ball method: the use of solid material in the liquid flow rate to determine the viscosity of the liquid.
(3) bubble method: the use of air flow rate in the liquid to determine the viscosity of the coating, only applicable to transparent varnish.
Non-volatile content:
non-volatile content is also known as solid content, is the paint part after construction left to become a dry coating film part, its content on the film quality and the use of the value of the coating has a great relationship. In order to reduce the pollution of organic volatiles to the environment, the production of high solid sub-coatings is one of the directions of the efforts of paint manufacturers. The common method of determination is: the paint at a certain temperature heating and baking, after drying the remaining material and sample quality comparison, expressed as a percentage. The standard is GB/T 9272-1988.
stability: water-based
mainly used as a base for synthetic resin emulsions. If after being frozen and melted several times, the original performance can still be maintained, it has the stability of freezing and melting. It can be measured by GB/T9268-1988.
paint construction performance testing
coatings can only play a role through construction. The construction performance of the coating, including coating on the substrate until the formation of the paint film, the main performance is as follows:
construction:
according to the construction method, the construction is divided into brush coating, spraying, scraping, that is, the paint in the brush, spray, scraping method construction, both easy to construct, but also can get the coating film quickly level, no hanging, wrinkle, shrink edge, seepage bite bottom or turn yellow and other phenomena. The measurement method is based on GB/T 6753.6-1986.
: The drying
coating is divided into different stages according to the change process of coating physical characteristics (mainly viscosity). The habit is divided into three stages: surface drying, actual drying and complete drying.
(1) table drying time: latex paint at 25 degrees C at room temperature, table drying time of 2 hours, commonly used GB/T 1728-1979 (89) in the blow cotton ball method, finger contact method and other detection.
(2) actual drying time: latex paint at 25 degrees C at room temperature, the actual (complete) drying time of 7 days, commonly used GB/T 1728-1979 (89) in the pressure filter paper method, cotton ball method, blade method and thick layer drying method and other tests.
coating rate:
coating rate refers to the unit coating area when the coating area of the unit mass (or volume) reaches the specified coating thickness or scrub resistance under normal construction conditions. The units are 2/kg or m2/L.
leveling:
the coating's ability to expand into a flat, smooth surface after construction. The leveling of the coating film is a combination of gravity, surface stress and shear force. Measured with GB/T 1750-1979 (89).
flowing:
liquid coating coated on the vertical surface of the object, affected by gravity, part of the wet film surface is prone to downward fall, the formation of the upper thinning, the lower thickening or serious formation of hemispherical (teardrop-like), ripple-like phenomenon. The main reason for this is that the flow characteristics of the coating is not suitable, wet film is too thick. The GB/T 9264-1988 mid-stream hanger was used for determination.
coating film thickness:
coating film thickness wet film thickness and dry film thickness, wet film thickness with GB/T 1345.2-1992 wheel gauge and comb gauge determination;
cover force:
paint is evenly applied to the surface of the object, through the film absorption, reflection and scattering of light, so that the substrate color no longer presents the ability to be called the cover force. GB/T1726-1979 (89) and GB/T 9270-1988 can be measured. The minimum coating usage (g/m2) required to cover the unit area is used to indicate the masking force.
use time:
Construction use time for two- or multi-component coatings (i.e. the components can still be used normally after the specified time has been placed after mixing in the container).
Coating performance detection
coating appearance:
in the indoor standard state prepared after the model drying, in natural light for the naked eye observation, check the paint film for defects such as brush marks, particles, foaming, wrinkles, shrink holes and so on and compared with the standard model.
: The
shines on a smooth surface, partly reflected and partly penetrated into the interior to produce refraction. The ratio of the light strength of the reflected light to the light strength of the incoming light is called the reflectivity. The luster of the paint film is the ability of the surface of the paint film to reflect the light shining on it in a certain direction, also known as the specular gloss. The greater the reflectivity, the higher the gloss. China according to GB /T 1743-1979 (89) to determine the gloss.
: The main
is to aircraft, high-class cars, such as the film decorative rating.
:
color is a visual, that is, different wavelengths of light stimulate the human eye, caused by the reflection in the brain. Therefore, the color of the coating film is determined by the light source, the coating itself and the human eye. Due to the limitations of color memory ability and natural conditions, human error is inevitable. It can be carried out according to GB/T 9761-1988 standard.
: The
is the resistance of the paint film to another object with a higher hardness on it. The methods used to determine the hardness of the coating film are swing rod damping hardness, scratch hardness and indentation hardness. Here is the main introduction of scratch hardness method. Scratch hardness method is to use hard object scratch coating film on the surface of the paint film to determine hardness. It is commonly used for pencil hardness. GB/T 6739-1986 specified the use of pencils from 6B to 6H a total of 13 levels, can be operated by hand, can also be tested by instrument.
impact strength:
also known as impact resistance, is to detect the coating film in high-speed gravity under the action of anti-instant deformation without cracking, do not fall off the ability. It reflects the film flexibility and adhesion to the substrate. The impact tester can be used for determination according to GB/T 1732-1979 (88).
flexibility:
when the paint film is bent by external forces, the combined properties of elasticity, plasticity and adhesion are called flexibility. The flexibility assay in GB/T 1731-1993 was used.
adhesion:
of the binding force produced by the coating film on the surface of the substrate. The methods of measurement are the method of rowing, the method of circleing and the method of pulling apart. The rowing method is to cross-cut a grid with a cross-cutting distance of 1mm, the number of grids is 5×5, and then according to GB/T 9286-1988 according to the rating standard classification, 0 is the best, 5 is the worst.
wear resistance:
coating resistance to mechanical wear, is a combination of film hardness, adhesion and cohesion. Mainly used in road sign paint, floor paint detection.
re-painting and paint matching:
re-painting refers to the difficulty and effect of re-painting with the same coating on the surface of the coating. The test is after the dry paint film according to the provisions of polishing, according to the prescribed method to apply the same coating, in the thickness of product requirements, check the ease of coating, after coating the photo-visual coating film conditions, and after the prescribed time drying to check the coating film for defects. Paint matching is the measurement project of primer, and its significance and measurement method are similar to re-painting.
wash resistance:
determines the relative abrasiveness of coatings when they are repeatedly washed to remove contaminants during use. In particular, the inner wall paint, easy to get dirty, need scrubbing, wash resistance is the evaluation index of this performance. The national standard is GB/T 9266-1988.
: The
ability of the coating film to maintain its original color, gloss and other optical properties after exposure to light is called rotary light resistance. It can be detected in such aspects as photoresist, color preservation and yellow degeneration resistance.
(1) Light preservation, color preservation: the preparation of a model cover part, in sunlight or artificial light sources after a certain period of time, comparing the shiny and color of the irradiated part and the unresolve part, you can get its ability to maintain.
(2) Yellow resistance: the sample is applied to the frosted glass, dried and placed in a dryer filled with a solution of potassium sulfate, after a certain period of time, the color of the three stimulus values X, Y, Z, and then calculated the degree of yellowing value D.
calculation formula: D-1.28X-1.06Z/Y
Note: X, Y, Z are three parameters in the C, I, and E coordinate system promulgated by the International Lightness Commission, i.e. the reflectivity of the red filter is X under a fixed light source;
water resistance:
water resistance measurement methods have normal temperature immersion method, boiling water immersion method, 40 degrees C constant temperature flow water immersion method. It is commonly used to immerse water at room temperature. The national standard is GB/T 1733-1993.
:
usually refers to the degree to which dirt on the surface of the coating is scrubbed with a wet towel (or a moderate amount of washing powder in water), also known as contamination resistance.
in addition to salt water resistance, chemical resistance, solvent resistance, moisture resistance, atmospheric aging resistance.
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