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Aerosol Paints Excellent Wettability And Dispersibility Of Pigments

Jun 12, 2017

Aerosol Paints NR or synthetic rubber is a highly unsaturated high molecular weight polymer, with high viscosity, slow film forming, and easy aging, not suitable for making paint. Modified by chlorination to reduce its molecular weight and change the unsaturated nature of the molecular structure, a natural rubber derivative-chlorinated rubber or cyclic rubber-is made. Chlorinated rubber is tasteless, non-toxic white powder or fine flake solid, no irritation to human skin, dissolved after a yellowish solution, the formation of the film has good adhesion, chemical corrosion resistance, fast drying, impermeable water and non-flammable. In the last century 60 's chlorinated rubber coating technology gradually matured, soon become a coating industry in a large system, is widely used in architectural coatings, chemical anti-corrosion coatings, Fire coatings, road marking coatings, automotive chassis coating, marine and ocean steel structure anti-corrosion coatings, and at room temperature curing epoxy resin coating and listed as the world's two major anti-corrosion coatings system. In this paper, the characteristics and coating method of chlorinated rubber anticorrosive coatings are summarized.

1.1.2 Modified Resin

Some natural resins or synthetic resins are usually used in the chlorinated rubber coating to improve the performance of the film, such as gloss and light stability, mechanical properties and construction. Resins that can be used with chlorinated rubber resins are: Medium and long oil alkyd resin,Aerosol Paints polyurethane resin, acrylic resin, epoxy resin, phenolic resin, rosin, glycerin rosin ester, etc. It is incompatible with cellulose acetate, ethyl cellulose, nitrocellulose and vinyl acetate copolymer.

The types and dosage of modified resins have a great effect on the performance and cost of chlorinated rubber paint, and the dosage of resin is generally: chlorinated rubber: Modified resin: plasticizer 1:1:0.5.

1.2 Auxiliaries

1.2.1 plasticizers

The chlorinated rubber molecule contains many six-yuan rings, and its individual coating is brittle, so it must be modified by plasticizer. The correct selection and addition of plasticizers is very important to change the performance of paint film, because chlorinated rubber is inert resin, so the requirement for plasticizer is that the plasticizing effect is obvious and can be basically close to the performance of chlorinated rubber (inert) to ensure the stability of the base material. Many plasticizers are compatible with chlorinated rubber, so the selection range is wide, for example: chlorinated paraffin, chlorinated biphenyl, dibutyl phthalate, phthalic acid dioctyl ester, phosphoric acid tri-cresol ester and drying (linseed oil, tung Wood, soybean oil and epoxidized soybean oil) etc. Among them, chlorinated paraffin as the plasticizer of chlorinated rubber is the most suitable, in addition to having the above requirements also have excellent pigment wettability and dispersibility, and other coatings with resin miscibility and excellent chemical resistance. In addition, it is required to use phthalic acid ester as plasticizer in the topcoat with good weathering resistance.

The ratio of chlorinated rubber to chlorinated paraffin has a great influence on the tensile strength, elongation, flexibility, water vapor permeability and adhesion of the coatings. The optimum range of proportions is narrow in order to achieve the best possible balance of performance. Because of the different types and dosage of pigments and fillers, the ratio of plasticizer to chlorinated rubber is also different, so the best proportion of the test test should be done. In general,Aerosol Paints when chlorinated rubber and chlorine content of 42% chlorinated paraffin ratio of around 70:30, the flexibility and adhesion of the film to achieve the best value, and maintain a better resistance to water vapor permeability.

1.2.2 Anti-settling agent

In order to prevent and improve the sedimentation and caking of pigment in chlorinated rubber paint, the appropriate amount of anti settling agent should be added, such as organic bentonite gum,Aerosol Paints gas phase silica and hydrogenated castor oil, in which hydrogenated castor oil has obvious thickening and preventing effect. Amide-Modified hydrogenated castor oil is often used as thixotropic agent in the preparation of thick paste paint.

1.2.3 other Auxiliaries

Chlorinated rubber resin is not good for the dispersion of pigments and fillers, which is usually dispersed with modified resins or chlorinated paraffin wax. In order to improve the pigment dispersion, storage stability and surface state of paint, sometimes a small amount of wetting dispersant, such as Byk-P104, de Disponer904s.

Roller coating construction or high-pressure airless spraying, especially thick slurry type chlorinated rubber paint, paint film easy to produce bubbles, so in the production of paint should be added to the amount of defoaming agent, such as EFKA-2035, Byk-066 and so on.

The chlorinated rubber paint modified by alkyd resin also needs to be added a proper amount of organic acid metal soap driers, that is dry material, to accelerate the drying time of paint oxidation.

Chlorinated rubber is a highly chlorinated polymer, if there are iron ions in the varnish or containing aluminum, copper and other chlorides (except aluminum chloride, copper chloride) and other substances, in the storage process, because of the high temperature, water, and so on, often produces chemical reactions such as ALCL3, FECL3 and other products, Release HCl gas, and in the molecule to form a double bond and crosslinking, releasing heat to promote the paint temperature rise, viscosity increased until the gel,Aerosol Paints In particular the iron red chlorinated rubber paint in the summer prone to this situation. In order to ensure the storage stability of the paint, in addition to adding the necessary dispersant, the paint must be added stabilizer, such as zinc oxide, magnesium oxide, zinc naphthenate solution, low molecular weight epoxy resin, epoxidized soybean oil, phosphite, etc., the dosage is generally about 1% of pigment content.

1 The construction is not limited by the temperature: chlorinated rubber paint can be in the environment of 20-50 Shan construction, not subject to seasonal, temperature restrictions.

2 Easy to use: chlorinated rubber paint is mostly a single tank packaging system, do not need to deploy other parts of the construction site temporarily, that is, open the packaging drum, after mixing evenly, you can use.

3 Dry quickly: chlorinated rubber coating solvent drying of the physical film coating, and solvent release speed, after the coating is quickly dry film, at room temperature interval of 4-6 hours after the second coating.

4 can obtain thicker coating: chlorinated rubber thick slurry coating, if the use of high-pressure airless spraying, each dry film thickness can be up to 55, the highest dry film thickness can reach 120, so less number of coating road, you can get thick coating, construction cycle is short.

5 adhesion is good: chlorinated rubber coatings on steel metal surface, has good adhesion, while coating and coating between the solvent in the film can play a role in infiltration, so that the lower layer of mutual adhesion, thus strengthening the adhesion between the film.

6 Good anti-corrosion: Because chlorinated rubber itself is a chemical inert film, coating on water vapor and oxygen permeability is very low, only 1/10 of the alkyd, but also moisture, salts, acids, alkalis, oxidants, all kinds of corrosive gases, etc. have better resistance.

7 Maintenance Convenience: Repair Without the need to remove a strong old paint film, the new and old paint film because of the permeation of solvents can produce miscible phenomenon, strong adhesion. In some other varieties of paint film can also be coated with chlorinated rubber paint,Aerosol Paints so the maintenance is very convenient.

8 The anti-virus, the fuel-burning property is good: Because the chlorinated rubber coating contains high "chlorine" polymerization, it has the ability to inhibit the germ growth. If the surface of the equipment in case of fire, the film can decompose the chlorine gas, and has a certain effect of the ignition.