Based on the determination of heavy metal content, we choose the materials with stable composition, moderate fineness, low heavy metal content and no mercury and its compounds as the pigments and fillers of this coating, so that the product has good coverage, leveling, scrubbing resistance and anti-sedimentation.
In this way, it can be continuously hydrolyzed and condensed to produce [-Ti(Oi-CsH 7) 2O一], a polymer-like product.
The monoisopropoxy titanate coupling agent has the general formula iCaHzOTiXa, where X is a long carbon chain fatty acid ester group, phosphate group, pyrophosphate group, etc. Since there are three long carbon chain X groups on the titanium atom that are not easily hydrolyzed, they can mask the isopropoxy group in space to a certain extent, reduce the reaction activity of the isopropoxy group, and make the hydrolysis reaction difficult. Even if the KR-TTS coupling agent with the worst water resistance [its general formula is i-Cs Hz OTi(OC OR) 3], the water resistance of titanium tetraisopropoxide is much better. Nevertheless, the reactivity of the isopropoxy group still exists. If the monoisopropoxy titanate coupling agent does not pay attention to the drying and sealing wax emulsion composition during the storage period, it will still undergo a hydrolysis and condensation reaction like tetraisopropoxy titanium.
The possible hydrolysis and condensation reaction of KR-TTS coupling agent:
i-CsH, OTi(OC OR) a+Hz O(R COO) ：Ti OH+i-CgH OH
(R COO): Ti OH+i-CsH, OTi(O OCR) —
(R COO): Ti OTi(O OCR) s+i-CsH, OH
R is an aliphatic long carbon chain alkane group. There is no isopropoxy active group in the above-mentioned hydrolysis condensation product, and it cannot have a coupling reaction with inorganic pigments and fillers. Therefore, the monoisopropoxy titanate coupling agent has a shelf life And during use, you must pay attention to sealing and drying to prevent hydrolysis failure.
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