paint remover
The paint remover is a solvent or paste that can dissolve or swell the coating film, and is mainly composed of a solvent with strong dissolving ability, paraffin, cellulose, etc.
In the shipbuilding industry, mechanical methods such as manual shoveling, shot blasting, sandblasting, high-pressure water and abrasive jets are mainly used to remove old coatings. However, for aluminum hulls, mechanical methods are easy to scratch aluminum, so the main Use sandpaper to polish, paint stripper, etc. to remove the old paint film. Compared with sanding, the use of paint remover to remove the old paint film has the advantages of safety, environmental protection and high efficiency.
The advantages of using paint remover are high efficiency, use at room temperature, less corrosion to metal, simple construction, no need to increase equipment, and the disadvantage is that some paint removers are toxic, volatile, flammable, and costly. In recent years, a variety of new paint remover products have emerged, and water-based paint removers have also been produced. The paint removal efficiency has been continuously enhanced, and the environmental protection performance has been continuously improved. Non-toxic, low-toxic, and non-flammable products have gradually occupied the mainstream market of paint removers.
Principle of paint removal and classification of paint remover
1. Principle of paint stripping
The paint remover mainly relies on the organic solvent in the paint remover to dissolve and swell most coating films, so as to achieve the purpose of removing the old coating film on the surface of the substrate. When the paint remover penetrates into the polymer chain gap of the coating polymer, it will cause the polymer to swell, so that the volume of the coating film will continue to increase, and the internal stress generated by the increase in the volume of the coating polymer will weaken and Finally, the adhesion of the coating film to the substrate is destroyed, and the coating film develops from point-like swelling to sheet swelling, causing the coating film to wrinkle, completely destroying the adhesion of the coating film to the substrate, and finally the coating film is bitten off. clear.
2. Classification of paint remover
Paint strippers are divided into two categories according to the different film-forming substances removed: one is formulated with organic solvents such as ketones, benzenes, and ketones, and a volatilization retarder paraffin, commonly known as white lotion, and is mainly used for Remove old paint films such as oil-based, alkyd and nitro-based paints. This type of paint remover is mainly composed of some volatile organic solvents, which have problems such as flammability and toxicity, and are relatively cheap.
The other is a chlorinated hydrocarbon paint remover formulated with dichloromethane, paraffin and cellulose ether as the main components, commonly known as water flush paint remover, mainly used to remove epoxy asphalt, polyurethane, epoxy poly Cured old coating films such as phthalamide or amino alkyd resin. It has high paint removal efficiency, low toxicity and wide application. The paint remover with dichloromethane as the main solvent is also divided into neutral paint remover (pH=7±1), alkaline paint remover (pH>7) and acidic paint remover according to the difference of pH value.