Colorant with graphite as lead core; Commonly used solvents are water, ethanol, etc. Dioctyl phthalate and triphenyl phosphate are commonly used as plasticizers to reduce the flowing viscosity of resin at high temperature and improve the properties of molded products.
Lead stearate is often used as a stabilizer to prevent resin aging and inhibit oxidation process; Liquid paraffin and low molecular weight polyethylene were used as lubricants to improve the fluidity of resin melt.
The manufacture of resin thin lead core is to form graphitized structure by high temperature roasting and carbonization under the protection of inert gas (such as argon) or under sealed conditions, so that it has high mechanical strength and good writing performance.
Extended data:
I. mechanical pencil Structure
Pulsating motion structure is a basic structural form commonly used in movable pencils, which is mainly composed of pen holder, tip sleeve (nib), centering protection tube (movable damping), chuck (flower), locking hoop, spring and so on.
When the core tube is under pressure (finger pressure), it moves downward against the elastic force of the spring, so that the clamping jaw opens. At the same time, the lead core leaves its original position in the core storage tube under its own gravity and moves along the wall of the core protection tube for a certain length under the control of the damping ring of the braking element.
After the pressing pressure is released, the spring returns to its original position, and the lead core is automatically locked and positioned by the locking hoop and chuck, thus completing a pulsating core jacking process. According to this reciprocating motion, the core can be continuously pulsed.
Second, the classification of mechanical pencil
Mechanical pencil is divided into thick core (above 0.9m) and thin core (below 0.9m) according to the size of pencil diameter. According to the core jacking method, it can be divided into four types: falling core type, rotary type, pulsating type and automatic compensation type, and four types of movable pencils. Core-dropping type automatically discharges lead through the gravity of lead. Rotary conveying lead core. Pulse type (push type) conveys the lead core by pushing, and the structure has a push type, that is, pushing and discharging the lead core once.
Two-push type, the pen mouth is pushed out of the pen holder for the first time and the lead core is pushed out for the second time. Double-head push type, adopting double-head structure, shortens the distance between the chuck and the nib, so that the last remaining 8 ~ 15 mm lead in the movable pencil can be ejected without pushing, and continuous writing can be carried out. Automatic compensation (automatic core jacking) can automatically compensate the lead core and write continuously without rotating or pulsating devices.
Baidu Encyclopedia-mechanical pencil