Application of Catalysts in Paint Additives
Paint additives, also known as paint accessories, are auxiliary materials for preparing coatings, which can improve the performance of coatings and promote the formation of coatings. There are many kinds, including drying agent, toughening agent, emulsifier, thickener, pigment dispersant, defoamer, leveling agent, anti skinning agent, matting agent, light stabilizer, mildew inhibitor, antistatic agent (see plastic additives), among which drying agent and toughening agent are used in large amount. At present, the research of paint additives focuses on the additives used in water emulsion paint.
Chinese Name: Paint Additives
Foreign name: Paintadditives
Also called: paint accessories
Used for: auxiliary agent of water emulsion paint
3 Detailed introduction
Paint additives refer to those ingredients added in a small amount to the paint formula, which can control or enhance the performance of the paint. There are about 40 types of coating additives with different functions (emulsifier, dispersant, defoamer, thickener, anti shrinkage agent, drying accelerator, bactericide, etc.), as well as additives with different chemical compositions. Generally, the formulation of coatings will contain a variety of additives. Generally, the total amount of additives used is less than 5% of the total formulation, but in some cases it may be as high as 10% or more. Due to the relatively high value of additives, the amount of additives used will be reduced as much as possible during formula design.
After years of development, there are many kinds of coating additives, which have played different roles in various stages of coating production. The manufacturing stage includes initiator, dispersant and transesterification catalyst; The reaction process includes: defoamer, emulsifier, filter auxiliary, etc; The storage stage includes anti skinning agent, anti precipitation agent, thickener, thixotropic agent, anti floating color and anti gelling agent, etc; The construction stage includes: leveling agent, anti shrinkage agent, anti sagging agent, hammering agent, flow control agent, plasticizer, defoamer, etc; The film forming stage includes: coalescence aids, adhesion promoters (also called adhesion promoters), photoinitiators, light stabilizers, driers, brighteners, skidders, matting, curing, crosslinking, catalysis and other aids; The special functions are: flame retardant, biocide, alga resistant, antistatic, conductive, corrosion inhibition, rust prevention and other additives.
Generally speaking, it includes adhesion promoter, anti adhesion agent, anti shrinkage agent, anti blooming agent, anti floating agent, defoamer, anti foaming agent, anti gelling agent, viscosity stabilizer, antioxidant, anti skinning agent, anti sagging agent, anti precipitation agent, anti-static agent, conductive control agent, mildew inhibitor, preservative, coalescence additive, corrosion inhibitor, rust inhibitor, dispersant, wetting agent, desiccant, flame retardant, Flow control agent, hammering agent, drying agent, matting agent, light stabilizer, photosensitizer, optical brightener, plasticizer, slippery agent, anti scratch agent, thickener, thixotropic agent, anti rat bite agent, and other additives.
In addition to the main film-forming materials, pigments, fillers and solvents, a component added to the coating can significantly improve a specific performance of the coating or film. The dosage in paint formulation is very small. Mainly a variety of inorganic and organic compounds, including polymer.
Most of them are named according to their action characteristics. Wetting agent, dispersant, emulsifier, defoamer, etc. can improve the coating production process. Anti settling agent, anti skinning agent, preservative, freeze-thaw stabilizer, etc. can improve the storage performance and transportation of coatings. Anti sagging agent, leveling agent, anti floating color and anti blooming agent, defoamer, thickener, etc. are used to improve paint application performance and prevent paint film from being ill conditioned. UV absorbers, light stabilizers, flame retardants, antistatic agents, mildew inhibitors, etc. can improve the performance of the film and provide special properties.
Paint additives can also be divided into oily paint additives and water-based paint additives. The development of water-based paint additives has made a leap in line with the increasing attention to environmental protection in the world. There are more and more new environment-friendly additives. The application is more and more extensive. It is the mainstream of the development of coating additives in the future.
A kind of substances that can accelerate the drying of the coating film, and promote the absorption of oxygen and the polymerization of double bonds of the dry oil film. The utility model can shorten the drying time of the oil film from several days to several hours, which is convenient for construction and can prevent the contamination and damage of the wet coating film.
The oxides, salts and soaps of many metals have a drying effect, but the ones with practical value are lead oxide (red lead, yellow lead), manganese dioxide, lead acetate, lead nitrate, manganese sulfate, manganese chloride, manganese borate, manganese acetate, cobalt acetate, cobalt chloride, naphthenic acid soaps of lead, cobalt and manganese, linolenic acid soaps and rosin acid soaps.
Soap driers have good oil solubility, so they have high drying effect. Naphthenic acid soaps are commonly used as driers in modern paint industry. Naphthenic acid soaps are usually produced by double decomposition.
The amount of drier in the oily paint depends on the amount of dry oil or semi dry oil. Take dry linseed oil as an example, the amount of lead drier (calculated by lead) is 0.4~0.5% of the oil quality; The drying ability of cobalt and manganese is stronger than that of lead, and the ratio of cobalt, manganese and lead is about 8:1:40. Two or three metal soaps have synergistic effect when used together. In resin coatings, the amount of drier must be increased.
That is, plasticizer (see plastic additives). The varieties commonly used in the coating industry include diethyl phthalate, dibutyl phthalate, dioctyl phthalate, tributyl phosphate, triphenyl phosphate, trimethyl phenyl phosphate and some special varieties.
A substance that can increase the viscosity of a coating and reduce its fluidity. The important purpose of using thickener is to reduce the flowing phenomenon during finishing. Thickeners for coatings mainly include the following categories: ① white carbon black; ② Bentonite and organic bentonite (bentonite treated with cationic organics); ③ Activated calcium carbonate particles with surface treatment; ④ Hydrogenated castor oil; ⑤ Metal soaps, such as calcium stearate, aluminum stearate, zinc stearate, etc; ⑥ The ester of polymerized vegetable oil, fatty acid dimer and polyol.
Used to prevent pigment from settling or floating. Bentonite, organic bentonite, metal soap, hydrogenated castor oil and other thickeners can act as pigment dispersants. Various surfactants, low molecular weight polyethylene oxide (polyoxirane), low viscosity methyl silicone oil, lecithin and its derivatives are also commonly used.
A substance that helps to form a smooth finish. The materials that can reduce the surface tension of coatings generally have the effect of leveling agent. There are many series of leveling agents used in industry, such as fluorine-containing surfactant, polyacrylate and polyvinyl butyral. Generally, organosilicon leveling agent is used to control short wave leveling and reduce surface tension obviously; Acrylates are used to control long wave leveling and reduce surface tension slightly.
Anti skinning agent
Substances that can prevent oily coatings from skinning in use, such as methyl ethyl ketone oxime and cyclohexanone oxime.