Tourmaline Whitening Modification Technique And Its Application In Coatings

Contraposing the issue that quality of indoor air has been worsening for many decades, tourmaline functional coating which can produce air anions was made for alleviating the phenomenon in this paper. Many reports about application of tourmaline in coating emerged in these years, tourmaline was treated as padding and put into coating directly in most of them, usually the content of tourmaline in coating was low due to deep color of tourmaline through this way, that’s the reason why anion property of functional coating couldn’t attain requirement of indoor air eventually.Composite powder of tourmaline/coating agent with higher whiteness which contains high mass ratio of tourmaline has been produced in the way of powder coating through learning previous achievement. Phase structure of Fe-dravite with deep color was discussed, meanwhile the influence of heat treatment to properties of tourmaline, relations between each factor and properties of composite powder were researched. Model of coating was established to probe into how each factor influenced composite powder in theory, such as coating agent and stearic acid dosage. The issue that composite powder couldn’t be moistened in coating solvent was solved in a certain extent. Properties of tourmaline functional coating which was made of composite powder are tested to obtain alteration relevance with its content, following conclusions are obtained:1) After being heat-treated at500℃with2hours, pyroelectricity and free energy of Fe-dravite are both enhanced, Fe2+is oxidized into Fe3+in crystal, which causes contraction of unit cell, and enhancement of its whiteness (raised to16.2%from14.5%).2) According to model of coating, optimum volume ratio between coating agent and coupling agent is3.5:1, mass ratio of tourmaline in composite powder is decided by its own granularity, the bigger granularity, the higher mass ratio. But in other hand granularity is reciprocal for surface activity, free energy and pyroelectricity of tourmaline, proper granularity of tourmaline selects10μm through tests analysis. Optimum mass ratio of tourmaline in composite powder decides from quotient of covering power to coating thickness, so it’s got by calculating maximum of product between whiteness of composite powder and itself. Orthogonal tests show optimum in preparation of composite powder:TiO2acts coating agent, mass ratio of tourmaline is 33.6%, heated temperature is66℃, and whiteness of composite powder is76.2%, cladding enthalpy characterized for cladding intensity is3.5KJ/Kg, level of releasing anion is1280ions/cm3,3) The issue that composite powder can’t be moistened directly can be solved by adding OP-40which is surfactant in coating solvent, when its concentration gets1.1g/L, composite powder can be moistened and homodisperse in water-based paint. Putting mixture which was made of36.2portion acrylic resin,35.1portion water,26.8portion pigment and1,9portion auxiliaries into YWS-NQ water-based paint, testing results show when composite powder occupies9.8%in coating, namely tourmaline mass ratio is3.3%, the whiteness of coating is87.1%, and concentration of anion is830ions/cm3in detection box, and its whiteness and concentration are respectively14.2%and190ions/cm3higher than coating which contains the same mass tourmaline, it indicates that cooperativity between TiO2and tourmaline exists.