Wetting and adhesive coated abrasives with phenolic resin

A wetting mechanism wetting (wetting) refers to the solid surface with a liquid replaced by another immiscible fluid process that is solid interface by the solid - gas interface into a solid - liquid interface phenomenon. Bonding of the two materials ( or materials ) between its first condition is to be able to wet each other. Further, the wetting properties of adhesives and adhesion between the body is the main factor affecting the  quick change disc adhesion strength , good wetting properties can increase the work of adhesion between the two phases , which will help improve the adhesion strength. Phenolic resins are coated abrasive one of several synthetic resin industry to use in fabric treatment, primer , glue complex plays a very important role , with the wetting properties between the substrate and the abrasive directly affects the final product performance wetting phenomena into wet (ashesion), wet (immersions) and spreading (spreading) of three types . Method or process different wettability , ease of wetting and wetting conditions are different . Corresponding to three types of different contact angle spread is an  abrasive paper sheet ideal state . Related to this there are several important concepts, including contact angle , surface tension, surface free energy . The contact angle is judged whether the liquid wetting the most convenient method for a solid surface , the liquid droplets (L) on an ideal plane (S), if one phase is a gas , the contact angle is a gas - liquid interface through the liquid and solid - liquid interface of the clip angle . The minimum contact angle is 0 °, a maximum of 180 °. The smaller the contact angle , the better the wettability .
Surface tension: the role of the liquid surface layer along the surface gravity is not balanced because the molecules produced in either a tension on the line . Molecular force suffered not equal to zero, which together point to a direction perpendicular to the liquid inside , resulting in a liquid surface with automatic narrowing trend , this contraction force called surface tension. Surface tension (surface tension) is a characteristic of the material , the nature of its size and temperature, and the two-phase interface -related substances . Study of the liquid resin interface issues , generally indicated by surface tension . Surface free energy : Under conditions of constant temperature and pressure so that the system unit surface area increases , the outside world must work done on the system . Interface Problem solids , using free energy to be more appropriate. Solid surface can be divided into two types of high-energy surfaces and low energy surfaces . Surface energy refers to the surface of the metal and its oxide , silica, inorganic salts , and the surface free energy is generally between 500 ~ 5000mJ/m2. Hardness and melting point of  cut off wheel such materials is higher, the greater the surface free energy . Refers to a low energy surface organic solid surface, such as paraffin wax and a polymer compound . Their surface free energy of less than 100 mJ/m2. High surface energy to more readily absorb the liquid suction surface tension higher than the low surface energy , because of the lower surface free polyester fabric surfaces are low energy surfaces , and no polar groups, so that its surface is not easy to spread the adhesive and wetting there are two interfaces , one is a solid substrate , one is a liquid resin , mainly a phenolic resin. Bonding two ways to solve the problem to solve. Common approach to solve the problem of solid interface is treated substrate surface , increasing the surface free energy ; improve fabric processing formulations and processes. For a phenolic resin, a method to reduce the surface tension of the resin are mainly modified , an appropriate increase in temperature of the resin , adding a suitable surfactant.