Wide application of conductive barium sulfate in coatings

1. Features of conductive barium sulfate
Conductive barium sulfate is based on precipitated barium sulfate, using nanotechnology, through surface treatment and semiconductor doping treatment, to form a conductive oxide layer on the surface of the matrix, thereby preparing a new type of electronic conductive functional semiconductor pigment (filler) material . Conductive barium sulfate powder has low oil absorption, low consumption of paint base, good filling, leveling and impermeability, which can increase the hardness and wear resistance of paint film, easy to mix and disperse with other pigments and paints, and can be made into Thick film conductive, antistatic coating. Used in conjunction with other pigments, it can be made into permanent conductive and anti-static products of various colors such as near white. It is especially suitable for anti-static solvent-free epoxy floors and anti-static powder coatings.

Conductive barium sulfate powder is non-toxic, tasteless, acid-resistant, alkali-resistant, salt-resistant, organic solvent-resistant, light-resistant, stable below 800°C, non-oxidizing, non-flammable, and has a flame retardant effect. It is suitable for almost any environment and occasion requiring conductive and anti-static.

2. Technical indicators of conductive barium sulfate

Note: (1) The appearance of the product is generally light gray, and gray-white, gray and other color products can also be provided according to user requirements. The darker the color, the lower the resistivity, but it is not easy to color.

(2) The resistivity was measured under a pressure of 100kg/cm2.

(3) Oil absorption refers to the minimum grams of refined linseed oil absorbed by 100g of conductive powder. Generally speaking, the finer the powder, the greater the oil absorption.

(4) Determination of moisture content is calculated at 105±2°C drying constant weight.

(5) The specific surface area was determined by simple BET method or gas chromatography nitrogen adsorption method.

(6) pH value of aqueous suspension refers to the pH value of 5g powder dispersed in 100ml pH=7.0 water.

3. Suggestions on the use of conductive barium sulfate

The conductive properties of conductive and antistatic materials are related to conductive fillers, basic resins, additives, solvents, and processing and preparation techniques. In the coating system, they are also related to the electrical properties of the coated object. Under normal circumstances, when the amount of conductive barium sulfate added in the solvent coating is ~30% (weight percent PWC), the resistivity of the coating can reach 106-107 Ω·cm. Addition level of ~40% in antistatic powder coatings.

Conductive barium sulfate can be used alone or in combination with other conductive powders such as conductive mica powder. The filling structure of the conductive filler has a direct effect on the conductivity, and the non-uniform structure has better conductivity than the uniform structure, which can be explained from the size of the contact area. As far as the addition amount of conductive powder is concerned, the conductivity of the product increases with the increase of its addition amount. When it reaches a certain amount (called the critical addition amount or critical concentration), the electrical conductivity is the best, and then the electrical performance is more than stable. change or decline.

When conductive barium sulfate is used in a non-polar system, it is best to wet it with a solvent of similar polarity before stirring and dispersing, and then add the wetted slurry to the system for simple dispersion. The dispersion effect can be improved by increasing the stirring speed, adding dispersant, two-roll and three-roll grinding. If a dispersant is used, the dispersion time will be shortened. munzing wax emulsions for paints During the dispersion process, the shear force should not be too large, otherwise the structure of the conductive powder will be damaged. When using ball milling and sand milling for grinding, the fineness should be adjusted, the time should be shortened as much as possible, and the damage to the conductive powder structure should be minimized.

When conductive barium sulfate is used together with conventional pigments (fillers), conventional pigments (fillers) should be pre-dispersed by conventional methods, and then added to conductive powder by simple dispersion. Thixotropic agents (such as hydrogenated castor oil derivatives, organically modified bentonite, ultrafine SiO2, etc.) should be added to the coating to improve the anti-settling properties of the conductive powder. If sedimentation cannot be avoided, flocculants (such as Terrg-P, Anti-rerra-203, Texaphor-963, etc.) can be added to control the sedimentation, and it can be dispersed with simple stirring.