Coating Basic Knowledge Encyclopedia

First, the final text of the coating

A general term for a type of liquid or surface material that can form a solid coating film with protection, decoration or special functions (such as absolute line, anti-corrosion, identification, etc.) applied to the surface of an object.

Note: In the name of the specific paint variety, the word "lacquer" can be used to indicate "coating", such as blending paint, thick knee, etc

Second, the role of coatings

l. Protection    2. Decorative role    3. Special functions

Third, the composition of the coating

l. Film-forming substances

It is a substance that can form a continuous film with a certain strength in the lacquer base alone.Film-forming substances can be formed separately or bonded to pigments, fillers and other substances to form a film, it is the main substance that makes the coating rate adhere to the surface of the coated object to form a continuous coating, is the basis of the coating, determines the basic performance of the coating.

2. Pigments and fillers

Pigment: usually a powdery, insoluble medium of colored substances, which are used in coatings by hand because of their optical, protective, decorative and other properties.

Pigment (physique pigment): usually self-colored or slightly colored, a class of pigments with a refractive index of less than l,7, which is used in coatings due to its physical or chemical properties.

The pigment gives the coating color, tinting strength, and shading force, enhances mechanical strength, and has the properties of medium resistance, light resistance, weather resistance, heat resistance, etc.

Fillers or physique pigments generally have poor hiding power and tinting power, which mainly play the role of filling and reinforcing the environment, and also reduce costs.

3. Additives

Refers to any small amount of substance added to a coating to improve or otherwise alter one or more of the properties of the paint.

The amount of additives is very small, but it plays an important role in ensuring the coating and coating performance in the preparation, storage and coating process of modern coatings.

According to the role of additives in different stages of coating production, storage, transportation, construction, etc., it can be divided into:

●Additives to improve the processing performance of coatings: emulsifiers, IIII sprays, dispersants, defoamers, etc.

●Additives to improve the permeability performance of coatings: anti-sedimentation agents, anti-crusting agents, antifreeze agents, etc.

●Additives to improve coating construction and film-forming properties: leveling agents, matting agents, thousands of agents, etc.

●Additives for special functions of coatings: light stabilizers, antifungal agents, flame retardants, etc.

4. Dispersion medium (volatile substances, solvents)

Solvent: volatile under normal dry conditions and can completely dissolve lacquer-based one-component or two-component liquids.

Volatiles: Substances lost by volatilization under specified test conditions.

Dispersion media include organic solvents and water. The main function is to dissolve or disperse the binder into a viscous liquid for the application of the coating. During and after the coating is applied, these organic solvents and water volatilize to dry the film-forming substance.

In addition to considering its compatibility or dispersibility to the binder, the introduction of road agent also needs to pay attention to its volatility, toxicity, internal point and priceWait.

A paint variety can be used with either a single solvent or a mixture of solvents.

5. Commonly used paint terms

Current standards for coating terminology:

GLI/T 5206.1-85 'Paint' and Varnish Glossary Part 1 General Terms

GLI/T 5206, 2-:36 Pigments and varnishes Blend the second part of the material greaseterm

GBf "5206.3-86 Pigment Terms" and Varnish Glossary Part III: Pigment Terms

GL/T 5206, 4-89 color paint' and varnish with the fourth part of the physical and chemical properties of coatings and coating filmsterm

GB/T 5206.5-91 Pigment and varnish vocabulary Part 5: Sick terms for coatings and coating films

Commonly used general terms: coatings, blending paints, magnetic paints, paints, materials, paint bases, film-formers, solvents, pigments, fillers, pigment volume concentrations,Yan Kibi and others.

Commonly used cyanometric terms: hot spot resin, thermosetting resin, emulsion, alkyd tree feat, amino resin, epoxy resin, polyurethane acetate resin, etc.

Commonly used pigment terms: natural inorganic pigments, synthetic organic pigments, color pigments, pearlescent pigments, transparent pigments, titanium dioxide, lead self, group breeding, iron oxide, red powder, hue, brightness, tinting strength, oil absorption, easy dispersion, etc

Commonly used terms for the physical and chemical properties of coatings and coating films: transparency, density, knot, flash point, abrasive composition, speed, contrast ratio, hardness, flexibility, impact resistance, wear resistance, alkali resistance, damp heat resistance, salt resistance, natural aging, artificial aging, etc.

Commonly used pathological terms for coatings and coating films: modulation, anti-coagulation, gelatinization, knotting, pinhole, sagging, loss of gloss, blistering, opening, peeling, re-sticking, rusting, etc.

6. Classification and naming of coatings

Current standard: GB/T 2705-2003 "Classification and Nomenclature of Coating Products", which is a revision of the recommended national standard GB line 2705-92 "Classification, nomenclature and model of coating products". The main technical differences between this standard and the previous version are:

First, two classification methods are proposed: the classification method that takes the use of paint products as the main line and is supplemented by the main film-forming substances (classification method l) is added; The classification method based on the main film-forming substances is supplemented and improved, and the main uses of the product are appropriately supplemented, and the architectural coatings are highlighted (classification method 2).

First, the model of the dematerializing product has been canceled.

 (l) Nomenclature

The full name of a paint is generally composed of the name of the color or pigment plus the name of the film-forming substance, plus the basic name (characteristic or professional use). For pigment-free varnishes, the full name is generally composed of the name of the film-forming substance plus the basic name.

(2) The color name is usually composed of red, yellow, blue, white, black, green, decoration, brown, gray and other colors, sometimes plus dark, medium, light (light) and other words. If the pigment plays a significant role in the performance of the paint film, the name of the pigment can be used instead of the name of the color, such as iron red, zinc pen, red dan, etc.

(3) The name of the film-forming substance can be appropriately simplified, for example, polyurethane is simplified to polyurethane; Epoxy tree brain is simplified to epoxy; Nitrocellulose (cool) is simplified to nitro, etc. When the substrate contains a variety of film-forming substances, a film-forming substance that plays a major role is selected and named. If necessary; Enterprising two or three film-forming substances are named The main film-forming substances are named first, and the secondary film-forming substances are named last, such as red epoxy nitro enamel. The name of the film-forming substance can be found in Table B.2 in the standard attached B.

(4) The basic name indicates the basic variety, characteristics and professional use of the coating, such as varnish, magnetic paint, bottom velocity, hammer paint, canned paint, deck paint, automotive refinish paint, etc., and the basic name of the paint can be found in Appendix C of the standard.

(5) Between the name and the basic name of the film-forming substance, appropriate words can be inserted if necessary to indicate the professional use and characteristics, such as white nitro ball table magnetic paint, green nitro external magnetic paint, red perchloroethylene static electromagnetic paint, etc.

(6) The paint that needs to be baked and dried, and the word "drying" should be in the name (between the name of the film-forming substance and the basic name), such as silver gray amino drying magnetic paint, iron red epoxy polyester dynamic l whole drying insulating paint. If there is no word "drying" in the name, it means that the paint is naturally dry, or natural drying, and it can be baked and dry.

(7) For two-component (multi-component) coatings, the words "(two-component)" or "(three-component)" should be added after the name, such as polyurethane wood paint (two-component).

Note: In addition to diluents, individually packaged products that produce chemical reactions or do not produce chemical reactions after mixing can be considered as one of the paint components.

2. Classification of coatings

Sub-packaging method 1 is mainly based on the use of paint products, supplemented by the classification method of the main film-forming substances. Coatings products are divided into three main categories: architectural coatings, industrial coatings, and general coatings and ancillary materials. See Appendix A of the standard for details.

Classification method 2 In addition to architectural coatings, mainly produced by coatings. The main film-forming material of the product is the main line, and is appropriately supplemented by the classification method of the main use of the product. Coatings products are divided into two main categories: architectural coatings, other coatings and ancillary materials. See Appendix B of the standard for details.

The main items involved in paint performance testing

The coating is a polymer material, but the coating itself is a semi-finished product, and the resulting coating film is a polymer material.

If the polymer materials such as plastic, rubber, and fiber are different, they cannot exist independently, and need to adhere to other coated objects; In order to become a material for decoration protection. Coatings are materials that serve the coated object, so the coating and coating film need to have the required properties of the coated object.  

Performance of the paint in its original state

Coating application performance

The performance of the coating

Appearance and optical properties of the coating film             

Mechanical properties of the coating film

The coating film is resistant to liquid media and corrosion

1. The performance of the original state of the coating mainly includes: appearance and transparency, color, state in the container, density, viscosity, non-emitting content, fineness, storage stability, etc

2. The coating construction performance mainly includes: leveling, fluid control, fast capping force, dry operation time, coating film thickness, grinding property, etc

3. The appearance and optical properties of the coating film mainly include the appearance and color of the chaff film, light float, fog shadow, fresh reflection, etc

4. The mechanical properties of the coating film mainly include: time force, flexibility, impact resistance, and cupping(Recommended Instruments:Cupping Tester), hardness, wear resistance, scrubbing resistance, etc.;

5. The liquid medium resistance and corrosion resistance of the coating mainly include: water resistance, oil resistance, chemical medium resistance, P stain resistance, heat resistance, temperature degeneration resistance, salt spray resistance, damp heat resistance, weather resistance, etc.

11. Characteristics of paint testing

The focus of coating testing is the detection of coating film performance, and the detection of the performance of the coating product itself is mainly to examine the consistency of product quality.

2. Most of the tests on the performance of the coating film are carried out on the corresponding substrate, so the selection of the test substrate, the preparation process and quality of the coating film on the substrate have a significant impact on the test results.

3. There are multiple detection methods for the same test item, and the results obtained are often different, so the more appropriate method should be selected according to the requirements of crystal production performance.

4. Some test items are expressed by visual observation or comparison with the standard state, and the degree of change is expressed, and there are many interference factors in the evaluation of the results, which is easy to cause subjective errors.