Amine curing agents are the main curing agents for epoxy floor coatings. These curing agents mainly include aliphatic amine, aliphatic amine adduct, aliphatic amine adduct, polyamide, polyamide adduct, Mannich base and so on. Among all kinds of curing agents, aliphatic amine reacts with epoxy resin rapidly, releases heat, has high crosslinking density and good chemical resistance. Aliphatic amine adducts have been greatly improved in irritation, whitening and compatibility with epoxy resins. However, the cross-linking structure of the final coating is similar to that of aliphatic amine. It has high glass transition temperature and brittleness, and is mainly used in solvent-resistant coatings with high chemical resistance. 脂环胺及其加成物的许多性能较脂肪胺及其加成物有较大提高，如色浅、流平性好、光泽高、不泛白、不需诱导期，其玻璃化温度仍较高，主要用作无溶剂环氧地面涂料的固化剂。
Many properties of alicyclic amines and their adducts are better than those of aliphatic amines and their adducts, such as light color, good leveling, high gloss, no whitening and no induction period. Their glass transition temperature is still high, and they are mainly used as solventless curing agents for epoxy floor coatings.
Polyamide curing agent has excellent comprehensive properties. Long chain hydrocarbons in molecule have good plasticizing effect, which makes the film soft and impact resistant. The amide bond provides greater adhesion, wettability, peeling strength and tolerance to wet surface. Chemical resistance decreases compared with other amine curing agents, but still maintains high toughness. It is widely used as curing agent for solvent-based epoxy floor coatings.
The miscibility of polyamide and epoxy is not good, whitening and oiling still occur before construction, while polyamide adduct has good compatibility with epoxy resin, low content of free amine, which is easier to cure than standard polyamide under adverse conditions and can obtain yellow and frost-free coatings. So at present, most epoxy floor coatings use polyamide adduct as curing agent for floor coatings.
Mannich base, also known as phenolic amine, is characterized by the presence of phenolic hydroxyl groups in the molecule, which can promote curing. It is often used in low temperature, humidity and underwater curing coatings. Because the rigidity of benzene ring in molecule makes the film brittle, it is seldom used as solidifying agent of floor coating alone, and mostly used as solidifying agent of middle layer cement and mortar.
Dilutants are organic solvents that dissolve resins. The main function is to reduce the viscosity of the resin glue, but also conducive to the heat release from the resin curing process, which can properly prolong the service life of the glue. Dilutants can be divided into two categories: inactive diluents and active diluents.
1) The inactive diluent itself does not participate in the curing reaction, only achieves the purpose of physical mixing and viscosity reduction. Generally, the amount of resin added is 5% to 15% of the weight of the resin. When the resin is cured, part of the resin will escape, which will increase the shrinkage of the resin, reduce the bonding force, mechanical strength and thermal deformation temperature, and even produce stomata in serious cases. Special attention should be paid to the use of solvent-based epoxy floor coatings.
2) Types and use of active diluents. Active diluent has epoxy group and can participate in epoxy curing reaction of epoxy resin, so it has no evasive disadvantages.
It has little effect on the cured resin, but also plays a toughening role. The amount of toughening agent in the formulation can be reduced or not used. However, when active diluent is added, the amount of curing agent should be increased accordingly.
The film thickness of clean and wear-resistant floor coatings is 0.8-3.0 in one application. In order to prevent the film depression caused by volatilization of non-active solvents, active diluents are mostly selected to prepare solvent-free (volatile) self-leveling coatings. At the same time, it meets the requirements of environmental protection green coatings and further improves the construction conditions.
Excessive dosage of diluent also has a certain effect on the performance. As the diluent itself is a short chain molecule, the carbon chain is shorter than that of epoxy resin, which hinders the formation of the chain and affects the main properties of the film-forming material.
(4) Pigments and fillers
Epoxy floor resin wear-resistant floor coatings belong to thick paste coatings, the amount of coloring pigments can be less than ordinary pigments. On the other hand, the surface drying time of epoxy floor coatings is long, the use of organic pigments is easy to produce float, blossom and other problems, and the chemical resistance of organic pigments has limitations, so most of the inorganic pigments are used, such as drill white powder, chromium oxide green and iron oxide pigments.
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