The development of ADHD curing coating adhesion promoter.

0 Introduction . Compared with traditional coatings, UV-cured coatings do not contain any organic solvents or inert thinners, do not need to be heated when curing, with less environmental pollution, low energy consumption, high efficiency, good chemical stability, good applicability and so on, is an energy-efficient and environmentally friendly modern coatings, has been widely used in various fields. With the development and application of various photosensitive coatings, one of the keys to the formulation design of UV-cured coatings is how to improve their adhesion with various substrates, because good adhesion is the prerequisite for coating film to obtain good processing performance, media resistance and outdoor weather resistance.so how to improve the properties of coating film by increasing the adhesion of coatings is a concern for all of us. In general, it is possible to improve adhesion by adding a variety of adhesion promoters. Selecting suitable adhesion promoter to enhance the effective contact between coating film and substrate, using adhesion promoter with active function group and strong chemical bonding on the surface of substrate can obtain good adhesion and comprehensive performance. Because the promoter of this institute is a composite product with C-C single-official and dual-official groups, it can better cope with the problems of volume shrinkage and shrinkage stress when light curing. Because there are few articles in this field reported at home and abroad, this paper has a certain role in theoretical research and practical application.1 test1.1 main raw materials and reagents P2O5, analysis pure, Tianjin chemical reagents six plants; H E M A, H E A, Analysis Pure, Tianjin Bodi Chemical;1.2 Main instruments and equipment four-mouth bottles, super thermostat water bath pot, powerful electric mixer, condensation return tube, acid titration meter, NDJ-79 rotary viscosity meter, infrared spectrometer, ultraviolet curing instrument, electric blow air drying box, electronic analysis balance.1.3 Synthesis process of phosphorus-containing promoter s.5 sadds 0.3 mol heMA and a certain amount of the inhibitor to the toluene to the berrium, stirring well and heating to 55 degrees C, slowly at Add 0.1 m o l P2O5 in batches to heat up the mixing system to 80 to 85 degrees C and continue to react to 2.5 h, i.e. the desired adhesion promoter, the product is a light brown viscous liquid. The degree of reaction is shown according to the tracking test of acid value in the later stage of reaction, and the acid value of the resulting product is about 316.1.4 Product Performance Indicatorsproduct performance indicators synthesized from the above processes can be found in Table 1.1.5 Preparation and testing of the curing filmwith the commercially available primer U V303 as the base material, under the same conditions, the promoter in accordance with the solid composition of 0, 1%, 2%, 3%, 5% added to it stirred evenly. After coating, the coating film is cured into a film under ultraviolet light, the curing speed is 5 m / m i n;2 Results and Discussion 2.1 Product Analysis and Structural SymptomsIn the process of feeding, we determined the quantity ratio of the substance of the reactant n (-OH) : n (P2O5) - 3:1, in order to obtain a single double-official energy of 1:1 mixed product. For example, the theoretical product of a complete reaction based on H E A is as follows:can infer the main group of the product from the reaction type above, using the infrared tester WQ F-410 to confirm the inference. The results of the infrared spectral test are shown in Figure 1.. As can be seen from Figure 1, there is no absorption peak at 3,440 c m -1, indicating that the - OH in HEMA has basically responded completely. 2 959.4 cm-1 is the telescopic vibration peak of methyl and Medyl C-H. The strong absorption peak at 1 720.0c m -1 is alpha, the C O telescopic vibration characteristic peak of beta unsaturated acid and the P-O H characteristic peak, which is strengthened due to the similar position of the absorption peak. The absorption peak at 1 635.6 c m -1 is the characteristic peak of the double key on the pre-cluster structure. The absorption peak at 1 171.7 c m -1 is a hydrogen-bonded P O. The strong absorption peak at 1 032.7 c m -1 is the telescopic vibration characteristic peak of P-O-C, indicating the presence of phosphate groups in the structure. In 960 to 1,000 c m -1 wide absorption peak is also P-O-H characteristic peak.
2.2 The performance of homemade products compared to commercially available adhesion promoters . After a large number of experiments, the relatively good results of the commercial adhesion promoter and homemade products were compared, in which the amount of promoter addition is the percentage of the total quality of the system. Comparison of curing film adhesion properties in Figure 2, Figure 3.As can be seen from Figure 2, Figure 3, the effect of these two promoters in photo-curing coatings is more obvious, and the improvement of adhesion is basically similar, especially in aluminum plate, the effect is better, adhesion can never be added before the 5 levels increased to 0 after the addition, mainly the reactive group in the promoter is easy to react with the active and high price of A l micro-corrosion and co-operation, but overall the performance of homemade products slightly better than marketed products. In order to obvious effect and do not affect the other properties of the coating, the amount of promoter is generally 1% to 2% as good. As can be seen from Figures 2 and 3, this promoter is suitable for polar substrates such as metals. The test also compared heA and HEMA as raw material products, the results show that the effect of the previous product is slightly worse, because H E M A products have more methyl, so in the case of rapid curing of ultraviolet light meth can resist the contraction of internal stress, thereby more effectively improve adhesion. In addition, it has been tested to know that this promoter can be suitable for temperature or heating cured coatings, the effect is also more obvious. 3 Conclusion With HEA, HEMA, P2O5 and so on as raw materials, the adhesion promoter with phosphoric acid group is synthesized by step-by-step feeding method, which has the characteristics of simple operation, low energy consumption and high product yield. This adhesion promoter is particularly suitable for use in UV-cured coatings, because the C C double bond in the promoter and ultraviolet light exposure conditions can be with the two-bond cross-curing film embedded in the coating, and the phosphate group can produce strong chemical bonds with the polar substrate, so the metal, glass, wood and other polar substrates have a very good attachment promoter. Its suitable addition generally accounts for 1% to 2% of the solid content of the coating. .