Selection and application of high performance phenolic resin for abrasive cutting disc manufacturing(4)
4 Influence of several important indexes of liquid phenolic resin on the performance of abrasive cutting disc
The liquid phenolic resin in the abrasive cutting disc is a first-order water-soluble resin and is mainly used as a wetting agent. The resin can better wet the abrasive, has low volatile content, suitable viscosity and good dissolution. It is used to coat the surface of the abrasive, and then the powdered phenolic resin in the bonding agent is adhered to the surface of the abrasive. Bonding layer.
The biggest characteristic of liquid phenolic resin is that it can be reacted by heating. When it is cured, it can react by itself or react with powdered phenolic resin.
For liquid phenolic resin, according to the degree of influence on the abrasive cutting disc, the order of product technical index dependence is: solid content, viscosity, gel time, free phenol content, curing time and water ratio (water solubility).
1) Solid content: Generally, the solid content is high. The bonding strength is high when the wet molding is used alone. In order to ensure the strength of the resin wheel and the hardness of the product, the solid content of the liquid phenolic resin should be not less than 70%. The most suitable range is 73 - 78%.
2) Viscosity: Due to the limitation of mixing equipment, the most suitable range of viscosity is 400-1200mPa.s, the viscosity is too low, and the volatile content is large. It will bring many disadvantages to the resin wheel with high density and high binder content. The viscosity is too high, the mixing is not easy to be uniform, and the wettability is lowered, which reduces the stability of the mixture.
3) Free phenol content: According to the status quo of several domestic mixers (single pot countercurrent, double pot countercurrent, double pot center feeding, etc.), the suitable range of free phenol is 10-18%. The free phenol is too high, and the grinding wheel is too hard. At the same time, the free phenol cannot be completely discharged due to the hardening of the grinding wheel, which causes the performance of the grinding wheel to be unstable, and the performance of the grinding wheel is attenuated. The free phenol is too low, the ability to dissolve the powdery resin is lowered, and the mixture is leaked. Powder, unevenness can.
With the successful development of compound dedusting agent, the control and development direction of liquid resin free phenol is to develop low phenol content, mainly to reduce environmental pollution and benefit mankind.