Cure characterization of powder coatings

A combination of techniques (differential scanning calorimetry (DSC) or thermo gravimetry analysis (TGA) and a modified version of DL-TMA) was used to characterize the different stages occurring during the curing of powder coatings. The procedures established enable to clearly define the periods of melting and flow, the gel point and the degree of conversion at gel point, all parameters affecting the visual aspect as well as the durability of a powder coating. A variety of powder coatings, forming a film via addition or condensation reactions, were used in this study.     

Gloss reduction in low temperature curable hybrid powder coatings

This study describes the crucial role played by acrylic resin and curing agents in the gloss reduction of low temperature curable hybrid powder coatings. The incompatibility of the acrylic resin with the primary (epoxy/polyester) resins induces a two-phase morphology and initiates the formation of micro-structured surface. DSC measurements on various mixtures reveal the relative reactivity and the role of curing agents in the gloss reduction. These results indicate that the optimization of relative reactivity and compatibility is required to achieve low gloss coatings at low curing temperature. In addition, the gloss level is strongly affected by extruding conditions. These experimental results give a possibility to develop matt and semi-matt low temperature curable powder coatings.     

Cure monitoring of thermoset coatings

The combination of favorable features of tensile mode dynamic mechanical analysis and torsional braid analysis leads to a useful method for cure monitoring of thermoset coatings. This sensitive technique allows the observation of cure reactions over a wide time and temperature range, thus including gelation and long-term curing in one measurement. Isothermal baking can be simulated realistically, since evaporation of volatile compounds like solvents or blocking agents is not hindered and the sample film is in direct contact with the heating atmosphere. Examples are given showing the cure behavior of automotive clear coats and electro coats depending on parameters like crosslinker type and catalytic agents.     

UV固化粉末涂料

叙述了紫外固化粉末涂料的机理、生产、施工及光引发剂的选择，并给出Uvecoat系列树脂的应用范围。     

抗菌粉末涂料

以无机氧化物包覆银离子抗菌剂制备的抗菌粉末涂料抑菌效果好、时效长。介绍抗菌添加剂 ,抗菌粉末涂料的涂膜性能及抗菌效果。     

Preparation and anticorrosive behavior of epoxy-polysiloxane hybrid coatings modified by polyetheramines

Inorganic/organic hybrid coatings based on epoxy-polysiloxane resin were prepared by using five types of curing agents, including 3-aminopropyltriethoxysilane (APTES) alone (control coating) and the mixtures of four types of polyetheramines (Jeffamine D230, D400, T403, and THF100) along with APTES (modified coatings). The mechanical, adhesion, and corrosion resistance properties of the hybrid coatings cured by different curing agents were studied. The dynamic mechanical thermal analysis results showed that the glass transition temperature and cross-link density of the modified coatings decreased with increasing of the chain length of polyetheramines. The impact resistance height of the modified hybrid coatings was more than one time higher than that of the control coating. The adhesion of the modified hybrid coatings was enhanced compared to the control coating except the coating modified by THF100. Compared with the control coating, comparable hardness and improved wet adhesion were attained for the coatings modified by polyetheramines D230 and T403 with shorter chain length, while the hardness and wet adhesion were decreased for the coatings modified by polyetheramines D400 and THF100 with longer chain length. The corrosion resistance behavior of the hybrid coatings was thoroughly examined by electrochemical impedance spectroscopy and salt spray tests. It was found that the corrosion resistance behavior of the hybrid coatings increased with D230 and T403 due to higher cross-link density and decreased with D400 and THF100 due to lower cross-link density.     

粉末涂料用混合机

主要讨论了在粉末涂料热熔挤出之前的混合,对混合、混合机器、混合机器的选择做了详细的说明,特别对现在比较热门的邦定工艺做了简单的介绍。     

Flamesprayed thermoplastic powder coatings

The effects of flamespray coating conditions on two ethylene-carboxylic acid copolymers (Primacor 1420 and Nucrel 535) and a polyether block amide (Pebax 5533) on crystallinity and mechanical properties were investigated by differential scanning calorimetry (DSC), Gardner impact resistance, and conical mandrel bend tests. Plastic flamespray provides a means to apply thermoplastic powder coatings in the field with a wide range of properties to meet specific application requirements. The flamespray process did not significantly affect the crystallinity in the polymers studied, however, polymers possessing functional groups in the backbone such as the polyether block amide may experience some reduction in physical properties during the flamespray coating process. We have also successfully applied some high temperature thermoplastics (such as liquid crystal polymers) providing for coatings, with outstanding temperature and chemical resistance.     

Cure mechanism and properties of acrylosilane coatings

Acrylosilane resin, a copolymer of trialkoxysilylalkyi methacrylate and other acrylic monomers, was developed for use as a vehicle resin for weather and chemical resistant coatings. This report discusses the crosslinking mechanism, hydrolysis and condensation reactions with two types of hardening catalysts: organotin and organic acid. This report also demonstrates the advantages of its coating properties in weather resistance, acid resistance, stain resistance, and adhesion to anodized aluminum. The coating properties are a function of its crosslinking mechanism.