What Are Alkyds?
The preparation method of alkyd resin is made by polycondensation of polyfunctional alcohol, polyacid, and vegetable oil or vegetable oleic acid.The number of double bonds in different types of vegetable oil or fatty acid molecules is different, which can be divided into dry, Semi-dry alkyd resin. Dry alkyd resin is self-drying in the air, and its drying is a process in which macromolecules are cross-linked and cured by oxygen in the air. According to the content of vegetable oil or vegetable oleic acid used, there are short oil, medium oil, long oil, ultra long oil, and ultra short oil alkyd resins. Alkyd resins are produced by melting and solvent methods. The melting method uses polyalcohol, polyacid, vegetable oil or vegetable oleic acid to heat under the protection of inert gas and cool it at high temperature. After the acid value reaches the requirements, it is diluted by adding a solvent. The solvent method is that the reaction raw material is reacted in a solvent xylene, and xylene as a solvent can generate azeotrope with water and accelerate the reaction speed. Compared with the melting method, the solvent method requires a lower reaction temperature, easier control of reaction conditions, and a lighter alkyd resin. The properties of alkyd resins are related to the type of oil. With different molecular weights and structures, the properties are also different. They have a wide range of applications in paints, coatings, and ships.
- Chinese name
- Alkyd resin
- Foreign name
- ALKYD RESIN
- CAS number
- 63148-69-6
- Points for
- Dry, semi-dry and non-dry
- The preparation method of alkyd resin is made by polycondensation of polyfunctional alcohol, polyacid and vegetable oil or vegetable oleic acid.The number of double bonds in different types of vegetable oil or fatty acid molecules is different, so it can be divided into dry, non-dry and Semi-dry alkyd resin. Dry alkyd resin is self-drying in the air, and its drying is a process in which macromolecules are cross-linked and cured by oxygen in the air. According to the content of vegetable oil or vegetable oleic acid used, there are short oil, medium oil, long oil, ultra long oil, and ultra short oil alkyd resins. Alkyd resins are produced by melting and solvent methods. The melting method uses polyalcohol, polyacid, vegetable oil or vegetable oleic acid to heat under the protection of inert gas and cool it at high temperature. After the acid value reaches the requirements, it is diluted by adding a solvent. The solvent method is that the reaction raw material is reacted in a solvent xylene, and xylene as a solvent can generate azeotrope with water and accelerate the reaction speed. Compared with the melting method, the solvent method requires a lower reaction temperature, easier control of reaction conditions, and a lighter alkyd resin. The properties of alkyd resins are related to the type of oil. With different molecular weights and structures, the properties are also different. They have a wide range of applications in paints, coatings, and ships.
Basic introduction of alkyd resin
- alkyd resins.glycerol -phthalic resin.
Classification of alkyd resin
- 1. According to different types of vegetable oils or fatty acids, alkyd resins can be classified into dry, non-drying and semi-drying according to the types of vegetable oils or fatty acids. Alkyd resins synthesized from unsaturated fatty acids or oils are dry oleic alkyd resins, which can be self-dried or dried at low temperatures, and No. 200 solvent oil is used as its solvent. Through the method of oxidative crosslinking, the dry alkyd resin can be self-dried in the air. In a certain principle, the dry alkyd resin is a modified product of the dry oil. The drying principle of this kind of paint film is that the alkyd resin molecules are crosslinked into macromolecules through a series of reactions. Dry oil has a low molecular weight, and the formation of macromolecules requires multiple steps of cross-linking, so it takes a long time for the paint film to dry. After the alkyd resin is synthesized from the dry oil, it is equivalent to increasing the molecular weight of the dry oil, and it requires less cross-linking points to cure into a film.At the same time, the paint film performance of the alkyd resin is significantly better than that of the dry paint film. . Non-drying oleic alkyd resin, which cannot be dried in the air, is often used as a plasticizer and multi-based polymer. Non-drying oleic acid resin contains warp groups, so amino resins can be used together with it to make paints. If a two-component self-drying paint is prepared, it can be formulated with polyisocyanate. The film performance of semi-dry alkyd resin is between dry and non-drying alkyd resin.
- 2. Classified by fatty acid or oil content in alkyd resin. Alkyd resins can be divided into long oil, medium oil, and short oil alkyd resins based on the content of fatty acids in the resin. Oiliness refers to the content of oil or fatty acid in alkyd resin. The oil content or fatty acid content of long oil alkyd resin is 60 ° / 70%, the oil content or fatty acid content of medium oil alkyd resin is 40% to 60%, and the oil content or fatty acid content of short oil alkyd resin is 30% to 40% In addition, there are ultra-long oil (more than 70%) and ultra-short oil (less than 30%). The comprehensive properties of alkyd resin are closely related to the type and oil degree of the oil or fatty acid used. [1]
- Alkyd resin
- Dry short oil alkyd resin
- Dry short oil alkyd resin contains 30% to 40% oil or fatty acid. It is mainly made from linseed oil, some tung oil, soybean oil, castor oil, azalea oil and other dry oils and their fatty acids. Alkyd resins have a viscosity of and require aromatic solvents to dissolve. The alkyd resin paint is sprayed or dip-coated, preferably without brushing. It can be automatically oxidized and dried at room temperature, with good self-drying performance and general flexibility, good gloss, light and color retention, weather resistance, and fast drying speed. Short oil alkyd resin has high hardness, good gloss and abrasion resistance. It is suitable for metal products such as automobiles and machine parts, and can be used as topcoat and primer. Short oil alkyd resin can be used alone as a drying paint, and can also be mixed with atmosphere-based resin, urea-formaldehyde resin and so on.
- Dry medium oil alkyd resin
- Medium oil alkyd resin contains 40% ~ 60% oil or fatty acid.It is most commonly used in alkyd resins. The paint made by it can be sprayed, brushed, and coated. The paint film dries quickly, and has good gloss and weather resistance. Can be dried by itself or mixed with oxy resin. The drying time is shorter, the oil-based alkyd paint is longer, and the gloss retention and color retention are slightly worse. Dry medium oil alkyd resin is used as self-drying varnish, primer, etc. It can also be used as decorative paint, architectural paint, furniture paint, metal primer, etc., and can be applied to metal, wood and other materials.
- Non-drying oil alkyd resin
- The vegetable oil of non-drying oil alkyd resin can be selected from coconut oil, sesame oil, etc. It can also be made from lauric acid and some saturated fatty acids and low- and medium-carbon synthetic fatty acids. The short oil degree alkyd resin has an oil degree of 30% to 40%, is made of the above oil or fatty acid, and uses aromatic warp as a solvent. Non-drying medium-oil alkyd resin is mainly synthesized by castor oil, which has high polarity and uses aromatic hydrocarbons as solvents. Non-drying oil alkyd resin is often used in nitrocellulose paint, amino resin paint, etc.
- Long oil alkyd resin
- Long oil alkyd resin contains 60% ~ 70% oil or fatty acid. Dry long oil alkyd resin has good drying performance, good elasticity of paint film, good light and color retention and weather resistance, but the film hardness and abrasion resistance are worse than medium oil alkyd resin. Long oil alkyd resin is soluble in aliphatic hydrocarbon solvents, has low viscosity, is easy to apply by brushing, and has good leveling performance. It can be used for indoor and outdoor architectural coatings and marine coatings. Oil-based resin paint and latex paint.
- Very long oily alkyd resin
- Very long oily alkyd resin contains more than 70% oil or fatty acid, is soluble in aliphatic hydrocarbon solvents, and is compatible with oil-based resin paints. This alkyd resin dries slowly, but has excellent brushability and weather resistance. Can be used in inks, tinting bases, and outdoor house paints. [1]
Alkyd resin modified by alkyd resin
- After years of research, the mastery of alkyd resin synthesis technology has been relatively thorough. The synthetic raw materials are easy to obtain, the process is simple, and the comprehensive properties of the paint film are good. However, alkyd resins also have defects, such as slow drying of the coating film, low hardness, and unsatisfactory water resistance. The improvement of its performance must be modified. The current methods for modifying alkyd resins include acrylic acid resin modification, organic laurel modification, styrene modification, and nanomaterial modification.
- Acrylic acid modified alkyd resin
- Alkyd resin modified with acrylic acid resin has improved dryness, hardness and weather resistance. Propionic acid modified alkyd resin has two methods: physical mixing and chemical modification. The physical mixing method is to synthesize polyfunctional alcohol and acrylic acid under the premise of adding a polymerization inhibitor and a catalyst, and use benzene as a solvent. As a water-carrying agent, the solvent can accelerate the reaction to obtain a polyhydric alcohol acrylate. Commonly used acrylic acid is pentaerythritol tetrapropionate, trimethylolpropane tripropionate. After blending the polyol and alkyd resin in acrylic acid, the solid content of alkyd resin can be increased, and the drying performance and hardness of the paint film are improved. Yu Zhangqing and others synthesized a composite emulsion of polyacrylic acid and alkyd resin, which uses an emulsion polymerization method. Studies have shown that increasing the temperature of the reaction polymerization and increasing the amount of initiator can improve the stability of the emulsion and increase the alkyd The proportion of resin, mechanical stability and water resistance of the emulsion are also improved. Chemical modification methods include copolymerization and graft copolymerization. The copolymerization method is to first synthesize an alkyd resin, and then add unsaturated monomers for copolymerization. The graft copolymerization method firstly prepares an acrylic acid prepolymer having active groups, and then reacts with an alkyd resin. Glycerol grafting is commonly used in the monoglycerol esterification method. First, a prepolymer containing light-based acrylic acid is synthesized, which is quenched with monoglyceride, and then added with phthalic anhydride and polyol to obtain an alkyd resin. Zhao Zhongyi et al. Prepared an acrylic acid alkyd resin by an alcoholysis method. Studies have shown that the type and oiliness of vegetable oils, the molecular weight of two dilute acid prepolymers, the proportion of acrylic acid resin used, and the extent of the quenching reaction It has an impact on the properties of acrylic acid modified alkyd resin. The modified product combines the excellent properties of acrylic acid and alkyd resin, and the dryness, hardness and water resistance of the paint film are significantly improved. [1]
- Silicone modified alkyd resin
- Silicone-based coatings have excellent electrical insulation properties, high temperature resistance and corrosion resistance. The use of silicone-modified alkyd resins can significantly improve the weatherability and heat resistance of alkyd resins. The alkyd resin modified with silicone by cold spelling method has significantly improved outdoor weathering resistance. The preparation method is to first polymerize the organic cassia to form an oligomer, and at the same time, the resin's warp group can react with the oligomer, so that the organic cassia and the alkyd resin are combined by a chemical bond. During the preparation process, the properties of the modified product are affected by the type of catalyst and the light base content of the alkyd resin. An intermediate of silicone was prepared, and then glycerol and phthalic anhydride were added to make a modified alkyd resin. The results showed that the modified alkyd resin had excellent outdoor weathering resistance and ultraviolet resistance. [1]
- Styrene modified alkyd resin
- The coating film of styrene-modified alkyd resin has the advantages of good dryness, high hardness, and low cost. It can be used as a quick-drying paint and has become an important type of alkyd resin. The process routes of styrene-modified alkyd resin include: styrenation of fatty acids or oils, styrenation of monoglycerides, styrenation of alkyd resins, and quenching. In the esterification method, the post-styrene method is more practical and has been widely used. Studies by Ye Daiyong and others show that when alkyd resin is modified by styrene, its relative molecular weight greatly affects the performance of the product. Therefore, by appropriately changing the relative molecular weight of the modified alkyd resin, a modified alkyd resin with excellent properties can be obtained. Liang Zhigang and others synthesized tung oil-based alkyd resin. The modified product has good performance, significantly shortens the construction period and reduces the construction cost. Studies have shown that the acid value, viscosity and copolymerization methods of tung oil-based alkyd resin can affect the performance of copolymer products. The high-solids self-drying resin made by Chen Qingxiao and others used post-acetophenone smelting method. Compared with general alkyd resins, the paint film has satisfactory performance. This alkyd resin has been widely used in practice. Because styrene contains double bonds, homopolymers will be formed at high temperatures. Therefore, when reacting with alkyd resin, the homopolymer will affect the compatibility of styrene and alkyd resin, and the performance of the final modified resin coating film will be Affected, it is necessary to control the amount of homopolymer formation. [1]
- Nano modified alkyd resin
- The use of nanotechnology in coatings is very beneficial for improving the performance of coating films. Nanomaterials have specific functions. For example, nanoparticles have higher activity and larger specific surface area. Adding nanoparticles to coatings can greatly improve the performance of coatings. Nano-iron dioxide has become a research hotspot because of its small particle size, large specific surface area, strong ultraviolet absorption ability, and high surface activity. Nanoparticles have been used in coatings abroad to make luxury car paints. Studies have shown that the nanoparticles prepared by the uniform precipitation method are added to the alkyd resin at a certain ratio, and the overall performance of the nano-composite alkyd resin coating film is greater than that of the alkyd resin coating film without the nanoparticles. improve. However, due to the high activity of the nanoparticles and the high interfacial tension between the particles, it is easy to agglomerate. Therefore, the addition of a specific dispersant can alleviate the agglomeration problem of the nanoparticles. Even in the presence of the dispersant, high-speed mechanical stirring is required dispersion. It is an emerging issue to use nanoparticle modified alkyd resin to improve the comprehensive properties of alkyd resin and expand the application range of alkyd resin. [1]
Production method of alkyd resin
- Alkyd resin is a polymer that is condensed and acetated.Its synthetic raw materials are polyfunctional alcohols, polyacids, and vegetable oils or fatty acids.The main chain is polyester, the side chain is unsaturated fatty acids, and the residual warp groups or radicals. The molecular weight of the chain is low. Alkyd resin curing is achieved by condensation of side chain unsaturated fatty acids or via other groups with other resins. There are four main methods for preparing alkyd resins, which are alcoholysis, fatty acid, fatty acid-oil method and oil dilution method. [1]
- Alcoholysis
- The alcoholysis method is to add oil, polyhydric alcohol and polybasic acid to the reactor at the same time to heat and esterify. In the quenching process, the quenching of polyfunctional alcohols and acids is easier. The resulting polymer is insoluble in oil, so a heterogeneous system is formed, and gelation occurs at a low degree of reaction. At this time, the oil or fatty acid is not involved. reaction. Monoglycerol is usually used to overcome the incompatibility problem. The alcoholysis method is in the presence of a catalyst, at 220 ~ 240 o C, the oil is subjected to alcoholysis with a polyhydric alcohol, and the fatty acids are redistributed. After the alcoholysis is completed, a dibasic acid such as phthalic anhydride is added to generate a homogeneous resin. When synthesizing alkyd resin, whether the alcoholysis is complete or not has a great influence on the molecular size and structure of the product, which affects the molecular structure and molecular weight distribution of the alkyd resin. The alkyd reaction is similar to the transesterification reaction, forming an equilibrium mixture in the homogeneous phase, including monoglycerides, diglycerides, unalcoholized triglycerides, and free glycerol. The detection of the degree of alcoholysis is to detect the solubility of the alcoholysis in ethanol. The detection method is to take out 1 volume of alcoholysis and add more than 3 volumes of ethanol to it. If the solution is clear and transparent, it indicates that the alcoholysis is complete. At this time, it can react with the polyacid in the polymerization stage. The commonly used alcoholysis catalysts are mainly oxides. The addition of catalyst had no effect on the degree of alcoholysis, and greatly increased the rate of alcoholysis. The content of monoglyceride in the alcoholysis equilibrium system indicates the degree of alcoholysis reaction, and the content of glycerol monoacid and vinegar is not only good alkyd resin transparency, but also narrow molecular weight distribution, coating film has good water resistance, and Ideal hardness. Containing about 25% monoglyceride can obtain a transparent and uniform alkyd resin solution. The advantages of alcoholysis are: lower production cost, less rotten candle to raw materials, and easier control of production process operation. The disadvantages are: the acid value is not easy to fall, the resin is not dry, and the hardness of the coating film is not heard. [1]
- Fatty acid method
- The fatty acid method is to add polyfunctional alcohol, polyacid (anhydride) and fatty acid to the reactor at one time, stir and raise the temperature to 210 ~ 260 o C, esterify until the desired degree of polymerization, dissolve the resin into a solution, filter and purify . However, this one-step esterification method does not take into account the different reactivity and different cool structures between the different positions of the polyol, the fatty acid group, the hepatic acid hepatic group, and the half ester group formed by phthalic anhydride. The transesterification is very slow. The polyfunctional alcohol and phthalic anhydride react with a part of fatty acids to control a lower acid value, and the synthesized main chain has a higher molecular weight; the remaining fatty acids are added to generate an acid value resin, and this part of the fatty acids is a side chain. The alkyd resin prepared by the fatty acid method has a large viscosity and is light in color, ideal in drying performance and chemical resistance. The biggest advantage of this method is the great flexibility of the formulation, which can use a variety of polyols or acids. Selecting different types of fatty acids can change the properties of the desired alkyd resin. Compared with linolenic acid, pure linoleic acid can reduce the yellowing of the coating film. The disadvantages of this method are: fatty acids are obtained from the decomposition of triglycerides, and the use of fatty acids without using oil directly increases the cost and process; it requires the use of anticorrosive candle equipment; the melting point of fatty acids is high, and the It tank must be heated and insulated Equipment to maintain the liquid state of fatty acids. [1]
- Fatty acid-oil method
- In this method, a mixture of fatty acids, vegetable oils, polyols, and dibasic acids is added to the reaction mixture, and the temperature is stirred to 210 ~ 28 (rC, and the esterification is maintained to meet the specified requirements. The ratio of the amount of fatty acids to oil should be to achieve a homogeneous reaction mixed system It is suitable. The method has low cost and can obtain high viscosity alkyd resin.
- Oil dilution method
- The oil dilution method is to first prepare an alkyd resin by fatty acid or alcoholysis method, and then polymerize with a certain amount of mixed oil and maintain it at a high temperature of 20 (rc for a period of time until the mixture is homogeneous. The main purpose of this method is to increase the degree of oil, synthetic Alkyd resin has a good brushing effect, but the hardness of the paint film is not high, and the gloss retention and weather resistance are worse than the alkyd resin prepared by alcoholysis. [1]
Alkyd resin related information
Classification number of alkyd resin
- Flammable liquids, refer to GB3.3 Class 33645, UNNO.1866; IMDG CODE 3278, 3379, Class 3.3.
- Physical and chemical properties: yellow-brown viscous liquid. It is a solution of soybean oil modified pentaerythritol and phthalic anhydride polycondensate in No. 200 gasoline solvent.
- Hazardous characteristics are flammable, flash point is 23 61 . When exposed to high temperatures, open flames, and oxidants, there is a danger of burning. The pyrolysis products of the resin are toxic.
- Identify the type of accident: fire, poisoning, container burst.
Fire protection method of alkyd resin
- Firefighters must wear gas masks and full protective clothing. Use foam, mist water, dry powder, carbon dioxide, 1211 fire extinguishing agent, and sand to extinguish the fire.
- First aid: Patients who inhale pyrolysis gas should be removed from the contaminated area, rested and kept warm. Severe cases were sent to hospital for treatment.
Notes on storage and transportation of alkyd resin
- Dangerous goods.
- Packaging mark: Flammable liquid.
- Packaging method: iron drum.
- Storage and transportation conditions: Store in a cool and ventilated warehouse. Keep away from heat and fire, avoid direct sunlight, and store and transport it away from oxidants.
- Leakage treatment: first cut off all sources of ignition, wear gas masks and gloves, absorb with sand, and bury it in an open area for burial or incinerator. The contaminated ground should be scraped off with a putty knife, and a large area should be surrounded by fog The water curtain suppresses the explosion.