The latest generation of room temperature curing s

2022-07-31
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A new generation of room temperature curable silicone resin is used in the field of high temperature resistance and corrosion protection

a new generation of room temperature curable silicone resin is used in the field of high temperature resistance and corrosion protection

May 27, 2021

a new generation of room temperature curable silicone resin is used in the field of high temperature resistance and corrosion protection

the traditional silicone resin is a well-known resin structure, such as the silikophen of Evonik ® P series, with excellent anti-corrosion performance, sustained high temperature resistance up to 650 ° C. At present, this kind of coating needs to be cured at high temperature, which limits its application in large components and only applies to small metal parts, such as exhaust pipes, steam valves and ovens

the new generation of silicone resin contains a large number of alkoxy functional groups, which can be combined with specific catalysts to carry out hydrolysis condensation reaction at room temperature. Therefore, it is especially suitable for curing and film forming at room temperature, such as silikophen of Evonik ® AC series coating. Under the condition of continuous high temperature resistance, it can also maintain a certain degree of corrosion resistance

this new resin represents a new technology that enables it to be applied to large industrial components, such as heat exchangers, distillation columns or industrial vessels. There is no need to stop production because of its painting operation

01 chemical structure of silicone resin cured at room temperature

traditional silicone resin has methyl/phenyl functional groups and contains up to 95% siloxane in its skeleton. In typical high temperature cured silicone resins, the content of alkoxy functional groups is very low, and the polymer structure has high molecular weight. A small amount of alkoxy functional groups are crosslinked at about 250 ℃ for 30 minutes, as shown in Figure 1

Figure 1: reaction mechanism of methyl/phenyl silicone resin curing at high temperature

the new room temperature curing silicone resin is different from the previous generation of silicone resin. Ganfeng lithium established a lithium battery team mainly because it has the characteristics of oligomers. This means that they contain low molecular weight siloxane structures and high alkoxy functional groups. This characteristic also makes it have the characteristics of high solid content (up to 100%) and low viscosity (Table 1) in this field

Table 1: room temperature cured silicone resin (silikophen ® AC 1000 and AC 900) and high temperature cured silicone resin (silikophen ® Comparison of p50/x and p80/x)

01 hydrolysis reaction through moisture at room temperature

02 condensation reaction

Figure 2 reaction mechanism of curing methyl/phenyl silicone resin at room temperature

in order to achieve resin polymerization through condensation and crosslinking, these functional groups need to undergo hydrolysis reaction first to form silanol groups. These silanol groups will then react in the form of alcohol condensation. When this reaction is completed, the resin has the characteristics of polysiloxane and releases alcohol reaction by-products, as shown in Figure 2

02 performance characteristics of high heat-resistant anti-corrosion coating formulation based on normal temperature curing silicone resin

when the coating is fully cured, Silicone coatings provide the following properties:

coating performance

excellent corrosion resistance

excellent early chemical resistance (as shown in Figure 3)

permanent oxidation resistance and weather resistance

thermal stability

excellent long-lasting high temperature resistance

maintain high hardness (low thermoplastic) at high temperatures

maintain excellent yellowing resistance at high temperature

both AC series silicone resins can be used to prepare high temperature resistant coatings. However, there are some technical differences between them

silik, in particular, can achieve this kind of performance ophen at a more affordable price than all carbon fiber reinforced materials ® AC 900 has good pigment wettability and good compatibility with other resins. This kind of resin is helpful to prepare coatings with certain flexibility, and has strong advantages in cold and hot cycle testing

SILIKOPHEN ® The wettability of ac1000 to pigment is general, but the pigment has good stability under thermal stress, it is not easy to yellowing, and it shows very low smoke when heated for the first time

Figure 3 xylene wiping high-temperature resistant coating, based on high-temperature curing (I) and normal temperature curing (II)

the key is to learn to think, be good at analysis, and make correct decisions

03 conclusion

compared with the traditional high-temperature curing silicone resin, the normal temperature curing organic silicone resin is a better choice. Its high solid content and low viscosity can significantly reduce the VOC of the coating

in addition, this resin also has the characteristics of low odor and low smoke. When the formula is fully crosslinked and cured, the coating has excellent corrosion resistance, early chemical resistance and long-term high temperature resistance. These properties enable it to be used in chemical plants, power plants, waste incineration equipment and other large industrial facilities, and there is no need to stop production due to coating operations, thus reducing costs

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