Lithium ester is an organic material located at the end of the gel pen and used to seal the neutral ink in the ink tube. Traditional oil-based ballpoint pens do not need to be filled with lithium-based esters, because oil-based ballpoint pen inks are hard to volatile substances, and there is basically no ink thickening or drying up caused by solvent volatilization. The neutral ink filled by the gel pen is mostly a water-lower alcohol suspension of pigments. It is prone to volatilization of the solvent when exposed to dry air for a long time, which causes the ink to become sticky and cannot write normally; in addition, low viscosity The neutral ink will flow back in the ink tube, and the lithium-based ester also plays a role in preventing the ink from flowing back. Lithium-based ester should be incompatible with neutral ink, the interface should be clear, no turbidity, and the bubbles in the ink tube can be easily removed by centrifugation after the pen is installed. Lithium esters are mostly polyorganosiloxane substances, immiscible with water, oily, good high and low temperature stability, no freezing at -20°C, no overflow or evaporation at 80°C, and excellent thixotropic fluidity. The excellent lithium-based ester enables the gel pen to maintain a good moisturizing seal even when the temperature changes greatly, preventing the ink from evaporating or overflowing; when writing quickly, the sealant can follow up at any time and the wall is lighter. Until the ink is completely written.

There are many types of gel pens on the market. According to the pen tip, there are stainless steel, nickel silver, lead brass, etc.; according to the different ball materials, it can be divided into tungsten carbide balls, modified ceramic balls, etc.; according to the pen structure Different, it can be bullet head, gourd head, needle tube head, etc. In recent years, the inner diameter of the gel ink tube has changed a lot, and different ink tubes with inner diameters from 2.0mm to 7.0mm have appeared. The amount of ink filled in the ink tube with a larger inner diameter has increased from 0.5g/piece to 2.0g/ The writing length of a single stick has been increased from 400-500m to nearly 2000m, which puts forward higher requirements on the wear resistance of the pen tip and the storage and follow-up performance of the lithium-based ester.